v4.19.13 snapshot.
diff --git a/fs/fat/Kconfig b/fs/fat/Kconfig
new file mode 100644
index 0000000..3ff1772
--- /dev/null
+++ b/fs/fat/Kconfig
@@ -0,0 +1,116 @@
+config FAT_FS
+ tristate
+ select NLS
+ help
+ If you want to use one of the FAT-based file systems (the MS-DOS and
+ VFAT (Windows 95) file systems), then you must say Y or M here
+ to include FAT support. You will then be able to mount partitions or
+ diskettes with FAT-based file systems and transparently access the
+ files on them, i.e. MSDOS files will look and behave just like all
+ other Unix files.
+
+ This FAT support is not a file system in itself, it only provides
+ the foundation for the other file systems. You will have to say Y or
+ M to at least one of "MSDOS fs support" or "VFAT fs support" in
+ order to make use of it.
+
+ Another way to read and write MSDOS floppies and hard drive
+ partitions from within Linux (but not transparently) is with the
+ mtools ("man mtools") program suite. You don't need to say Y here in
+ order to do that.
+
+ If you need to move large files on floppies between a DOS and a
+ Linux box, say Y here, mount the floppy under Linux with an MSDOS
+ file system and use GNU tar's M option. GNU tar is a program
+ available for Unix and DOS ("man tar" or "info tar").
+
+ The FAT support will enlarge your kernel by about 37 KB. If unsure,
+ say Y.
+
+ To compile this as a module, choose M here: the module will be called
+ fat. Note that if you compile the FAT support as a module, you
+ cannot compile any of the FAT-based file systems into the kernel
+ -- they will have to be modules as well.
+
+config MSDOS_FS
+ tristate "MSDOS fs support"
+ select FAT_FS
+ help
+ This allows you to mount MSDOS partitions of your hard drive (unless
+ they are compressed; to access compressed MSDOS partitions under
+ Linux, you can either use the DOS emulator DOSEMU, described in the
+ DOSEMU-HOWTO, available from
+ <http://www.tldp.org/docs.html#howto>, or try dmsdosfs in
+ <ftp://ibiblio.org/pub/Linux/system/filesystems/dosfs/>. If you
+ intend to use dosemu with a non-compressed MSDOS partition, say Y
+ here) and MSDOS floppies. This means that file access becomes
+ transparent, i.e. the MSDOS files look and behave just like all
+ other Unix files.
+
+ If you have Windows 95 or Windows NT installed on your MSDOS
+ partitions, you should use the VFAT file system (say Y to "VFAT fs
+ support" below), or you will not be able to see the long filenames
+ generated by Windows 95 / Windows NT.
+
+ This option will enlarge your kernel by about 7 KB. If unsure,
+ answer Y. This will only work if you said Y to "DOS FAT fs support"
+ as well. To compile this as a module, choose M here: the module will
+ be called msdos.
+
+config VFAT_FS
+ tristate "VFAT (Windows-95) fs support"
+ select FAT_FS
+ help
+ This option provides support for normal Windows file systems with
+ long filenames. That includes non-compressed FAT-based file systems
+ used by Windows 95, Windows 98, Windows NT 4.0, and the Unix
+ programs from the mtools package.
+
+ The VFAT support enlarges your kernel by about 10 KB and it only
+ works if you said Y to the "DOS FAT fs support" above. Please read
+ the file <file:Documentation/filesystems/vfat.txt> for details. If
+ unsure, say Y.
+
+ To compile this as a module, choose M here: the module will be called
+ vfat.
+
+config FAT_DEFAULT_CODEPAGE
+ int "Default codepage for FAT"
+ depends on MSDOS_FS || VFAT_FS
+ default 437
+ help
+ This option should be set to the codepage of your FAT filesystems.
+ It can be overridden with the "codepage" mount option.
+ See <file:Documentation/filesystems/vfat.txt> for more information.
+
+config FAT_DEFAULT_IOCHARSET
+ string "Default iocharset for FAT"
+ depends on VFAT_FS
+ default "iso8859-1"
+ help
+ Set this to the default input/output character set you'd
+ like FAT to use. It should probably match the character set
+ that most of your FAT filesystems use, and can be overridden
+ with the "iocharset" mount option for FAT filesystems.
+ Note that "utf8" is not recommended for FAT filesystems.
+ If unsure, you shouldn't set "utf8" here - select the next option
+ instead if you would like to use UTF-8 encoded file names by default.
+ See <file:Documentation/filesystems/vfat.txt> for more information.
+
+ Enable any character sets you need in File Systems/Native Language
+ Support.
+
+config FAT_DEFAULT_UTF8
+ bool "Enable FAT UTF-8 option by default"
+ depends on VFAT_FS
+ default n
+ help
+ Set this if you would like to have "utf8" mount option set
+ by default when mounting FAT filesystems.
+
+ Even if you say Y here can always disable UTF-8 for
+ particular mount by adding "utf8=0" to mount options.
+
+ Say Y if you use UTF-8 encoding for file names, N otherwise.
+
+ See <file:Documentation/filesystems/vfat.txt> for more information.
diff --git a/fs/fat/Makefile b/fs/fat/Makefile
new file mode 100644
index 0000000..70645ce
--- /dev/null
+++ b/fs/fat/Makefile
@@ -0,0 +1,12 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Makefile for the Linux fat filesystem support.
+#
+
+obj-$(CONFIG_FAT_FS) += fat.o
+obj-$(CONFIG_VFAT_FS) += vfat.o
+obj-$(CONFIG_MSDOS_FS) += msdos.o
+
+fat-y := cache.o dir.o fatent.o file.o inode.o misc.o nfs.o
+vfat-y := namei_vfat.o
+msdos-y := namei_msdos.o
diff --git a/fs/fat/cache.c b/fs/fat/cache.c
new file mode 100644
index 0000000..78d501c
--- /dev/null
+++ b/fs/fat/cache.c
@@ -0,0 +1,386 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * linux/fs/fat/cache.c
+ *
+ * Written 1992,1993 by Werner Almesberger
+ *
+ * Mar 1999. AV. Changed cache, so that it uses the starting cluster instead
+ * of inode number.
+ * May 1999. AV. Fixed the bogosity with FAT32 (read "FAT28"). Fscking lusers.
+ */
+
+#include <linux/slab.h>
+#include "fat.h"
+
+/* this must be > 0. */
+#define FAT_MAX_CACHE 8
+
+struct fat_cache {
+ struct list_head cache_list;
+ int nr_contig; /* number of contiguous clusters */
+ int fcluster; /* cluster number in the file. */
+ int dcluster; /* cluster number on disk. */
+};
+
+struct fat_cache_id {
+ unsigned int id;
+ int nr_contig;
+ int fcluster;
+ int dcluster;
+};
+
+static inline int fat_max_cache(struct inode *inode)
+{
+ return FAT_MAX_CACHE;
+}
+
+static struct kmem_cache *fat_cache_cachep;
+
+static void init_once(void *foo)
+{
+ struct fat_cache *cache = (struct fat_cache *)foo;
+
+ INIT_LIST_HEAD(&cache->cache_list);
+}
+
+int __init fat_cache_init(void)
+{
+ fat_cache_cachep = kmem_cache_create("fat_cache",
+ sizeof(struct fat_cache),
+ 0, SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD,
+ init_once);
+ if (fat_cache_cachep == NULL)
+ return -ENOMEM;
+ return 0;
+}
+
+void fat_cache_destroy(void)
+{
+ kmem_cache_destroy(fat_cache_cachep);
+}
+
+static inline struct fat_cache *fat_cache_alloc(struct inode *inode)
+{
+ return kmem_cache_alloc(fat_cache_cachep, GFP_NOFS);
+}
+
+static inline void fat_cache_free(struct fat_cache *cache)
+{
+ BUG_ON(!list_empty(&cache->cache_list));
+ kmem_cache_free(fat_cache_cachep, cache);
+}
+
+static inline void fat_cache_update_lru(struct inode *inode,
+ struct fat_cache *cache)
+{
+ if (MSDOS_I(inode)->cache_lru.next != &cache->cache_list)
+ list_move(&cache->cache_list, &MSDOS_I(inode)->cache_lru);
+}
+
+static int fat_cache_lookup(struct inode *inode, int fclus,
+ struct fat_cache_id *cid,
+ int *cached_fclus, int *cached_dclus)
+{
+ static struct fat_cache nohit = { .fcluster = 0, };
+
+ struct fat_cache *hit = &nohit, *p;
+ int offset = -1;
+
+ spin_lock(&MSDOS_I(inode)->cache_lru_lock);
+ list_for_each_entry(p, &MSDOS_I(inode)->cache_lru, cache_list) {
+ /* Find the cache of "fclus" or nearest cache. */
+ if (p->fcluster <= fclus && hit->fcluster < p->fcluster) {
+ hit = p;
+ if ((hit->fcluster + hit->nr_contig) < fclus) {
+ offset = hit->nr_contig;
+ } else {
+ offset = fclus - hit->fcluster;
+ break;
+ }
+ }
+ }
+ if (hit != &nohit) {
+ fat_cache_update_lru(inode, hit);
+
+ cid->id = MSDOS_I(inode)->cache_valid_id;
+ cid->nr_contig = hit->nr_contig;
+ cid->fcluster = hit->fcluster;
+ cid->dcluster = hit->dcluster;
+ *cached_fclus = cid->fcluster + offset;
+ *cached_dclus = cid->dcluster + offset;
+ }
+ spin_unlock(&MSDOS_I(inode)->cache_lru_lock);
+
+ return offset;
+}
+
+static struct fat_cache *fat_cache_merge(struct inode *inode,
+ struct fat_cache_id *new)
+{
+ struct fat_cache *p;
+
+ list_for_each_entry(p, &MSDOS_I(inode)->cache_lru, cache_list) {
+ /* Find the same part as "new" in cluster-chain. */
+ if (p->fcluster == new->fcluster) {
+ BUG_ON(p->dcluster != new->dcluster);
+ if (new->nr_contig > p->nr_contig)
+ p->nr_contig = new->nr_contig;
+ return p;
+ }
+ }
+ return NULL;
+}
+
+static void fat_cache_add(struct inode *inode, struct fat_cache_id *new)
+{
+ struct fat_cache *cache, *tmp;
+
+ if (new->fcluster == -1) /* dummy cache */
+ return;
+
+ spin_lock(&MSDOS_I(inode)->cache_lru_lock);
+ if (new->id != FAT_CACHE_VALID &&
+ new->id != MSDOS_I(inode)->cache_valid_id)
+ goto out; /* this cache was invalidated */
+
+ cache = fat_cache_merge(inode, new);
+ if (cache == NULL) {
+ if (MSDOS_I(inode)->nr_caches < fat_max_cache(inode)) {
+ MSDOS_I(inode)->nr_caches++;
+ spin_unlock(&MSDOS_I(inode)->cache_lru_lock);
+
+ tmp = fat_cache_alloc(inode);
+ if (!tmp) {
+ spin_lock(&MSDOS_I(inode)->cache_lru_lock);
+ MSDOS_I(inode)->nr_caches--;
+ spin_unlock(&MSDOS_I(inode)->cache_lru_lock);
+ return;
+ }
+
+ spin_lock(&MSDOS_I(inode)->cache_lru_lock);
+ cache = fat_cache_merge(inode, new);
+ if (cache != NULL) {
+ MSDOS_I(inode)->nr_caches--;
+ fat_cache_free(tmp);
+ goto out_update_lru;
+ }
+ cache = tmp;
+ } else {
+ struct list_head *p = MSDOS_I(inode)->cache_lru.prev;
+ cache = list_entry(p, struct fat_cache, cache_list);
+ }
+ cache->fcluster = new->fcluster;
+ cache->dcluster = new->dcluster;
+ cache->nr_contig = new->nr_contig;
+ }
+out_update_lru:
+ fat_cache_update_lru(inode, cache);
+out:
+ spin_unlock(&MSDOS_I(inode)->cache_lru_lock);
+}
+
+/*
+ * Cache invalidation occurs rarely, thus the LRU chain is not updated. It
+ * fixes itself after a while.
+ */
+static void __fat_cache_inval_inode(struct inode *inode)
+{
+ struct msdos_inode_info *i = MSDOS_I(inode);
+ struct fat_cache *cache;
+
+ while (!list_empty(&i->cache_lru)) {
+ cache = list_entry(i->cache_lru.next,
+ struct fat_cache, cache_list);
+ list_del_init(&cache->cache_list);
+ i->nr_caches--;
+ fat_cache_free(cache);
+ }
+ /* Update. The copy of caches before this id is discarded. */
+ i->cache_valid_id++;
+ if (i->cache_valid_id == FAT_CACHE_VALID)
+ i->cache_valid_id++;
+}
+
+void fat_cache_inval_inode(struct inode *inode)
+{
+ spin_lock(&MSDOS_I(inode)->cache_lru_lock);
+ __fat_cache_inval_inode(inode);
+ spin_unlock(&MSDOS_I(inode)->cache_lru_lock);
+}
+
+static inline int cache_contiguous(struct fat_cache_id *cid, int dclus)
+{
+ cid->nr_contig++;
+ return ((cid->dcluster + cid->nr_contig) == dclus);
+}
+
+static inline void cache_init(struct fat_cache_id *cid, int fclus, int dclus)
+{
+ cid->id = FAT_CACHE_VALID;
+ cid->fcluster = fclus;
+ cid->dcluster = dclus;
+ cid->nr_contig = 0;
+}
+
+int fat_get_cluster(struct inode *inode, int cluster, int *fclus, int *dclus)
+{
+ struct super_block *sb = inode->i_sb;
+ struct msdos_sb_info *sbi = MSDOS_SB(sb);
+ const int limit = sb->s_maxbytes >> sbi->cluster_bits;
+ struct fat_entry fatent;
+ struct fat_cache_id cid;
+ int nr;
+
+ BUG_ON(MSDOS_I(inode)->i_start == 0);
+
+ *fclus = 0;
+ *dclus = MSDOS_I(inode)->i_start;
+ if (!fat_valid_entry(sbi, *dclus)) {
+ fat_fs_error_ratelimit(sb,
+ "%s: invalid start cluster (i_pos %lld, start %08x)",
+ __func__, MSDOS_I(inode)->i_pos, *dclus);
+ return -EIO;
+ }
+ if (cluster == 0)
+ return 0;
+
+ if (fat_cache_lookup(inode, cluster, &cid, fclus, dclus) < 0) {
+ /*
+ * dummy, always not contiguous
+ * This is reinitialized by cache_init(), later.
+ */
+ cache_init(&cid, -1, -1);
+ }
+
+ fatent_init(&fatent);
+ while (*fclus < cluster) {
+ /* prevent the infinite loop of cluster chain */
+ if (*fclus > limit) {
+ fat_fs_error_ratelimit(sb,
+ "%s: detected the cluster chain loop (i_pos %lld)",
+ __func__, MSDOS_I(inode)->i_pos);
+ nr = -EIO;
+ goto out;
+ }
+
+ nr = fat_ent_read(inode, &fatent, *dclus);
+ if (nr < 0)
+ goto out;
+ else if (nr == FAT_ENT_FREE) {
+ fat_fs_error_ratelimit(sb,
+ "%s: invalid cluster chain (i_pos %lld)",
+ __func__, MSDOS_I(inode)->i_pos);
+ nr = -EIO;
+ goto out;
+ } else if (nr == FAT_ENT_EOF) {
+ fat_cache_add(inode, &cid);
+ goto out;
+ }
+ (*fclus)++;
+ *dclus = nr;
+ if (!cache_contiguous(&cid, *dclus))
+ cache_init(&cid, *fclus, *dclus);
+ }
+ nr = 0;
+ fat_cache_add(inode, &cid);
+out:
+ fatent_brelse(&fatent);
+ return nr;
+}
+
+static int fat_bmap_cluster(struct inode *inode, int cluster)
+{
+ struct super_block *sb = inode->i_sb;
+ int ret, fclus, dclus;
+
+ if (MSDOS_I(inode)->i_start == 0)
+ return 0;
+
+ ret = fat_get_cluster(inode, cluster, &fclus, &dclus);
+ if (ret < 0)
+ return ret;
+ else if (ret == FAT_ENT_EOF) {
+ fat_fs_error(sb, "%s: request beyond EOF (i_pos %lld)",
+ __func__, MSDOS_I(inode)->i_pos);
+ return -EIO;
+ }
+ return dclus;
+}
+
+int fat_get_mapped_cluster(struct inode *inode, sector_t sector,
+ sector_t last_block,
+ unsigned long *mapped_blocks, sector_t *bmap)
+{
+ struct super_block *sb = inode->i_sb;
+ struct msdos_sb_info *sbi = MSDOS_SB(sb);
+ int cluster, offset;
+
+ cluster = sector >> (sbi->cluster_bits - sb->s_blocksize_bits);
+ offset = sector & (sbi->sec_per_clus - 1);
+ cluster = fat_bmap_cluster(inode, cluster);
+ if (cluster < 0)
+ return cluster;
+ else if (cluster) {
+ *bmap = fat_clus_to_blknr(sbi, cluster) + offset;
+ *mapped_blocks = sbi->sec_per_clus - offset;
+ if (*mapped_blocks > last_block - sector)
+ *mapped_blocks = last_block - sector;
+ }
+
+ return 0;
+}
+
+static int is_exceed_eof(struct inode *inode, sector_t sector,
+ sector_t *last_block, int create)
+{
+ struct super_block *sb = inode->i_sb;
+ const unsigned long blocksize = sb->s_blocksize;
+ const unsigned char blocksize_bits = sb->s_blocksize_bits;
+
+ *last_block = (i_size_read(inode) + (blocksize - 1)) >> blocksize_bits;
+ if (sector >= *last_block) {
+ if (!create)
+ return 1;
+
+ /*
+ * ->mmu_private can access on only allocation path.
+ * (caller must hold ->i_mutex)
+ */
+ *last_block = (MSDOS_I(inode)->mmu_private + (blocksize - 1))
+ >> blocksize_bits;
+ if (sector >= *last_block)
+ return 1;
+ }
+
+ return 0;
+}
+
+int fat_bmap(struct inode *inode, sector_t sector, sector_t *phys,
+ unsigned long *mapped_blocks, int create, bool from_bmap)
+{
+ struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
+ sector_t last_block;
+
+ *phys = 0;
+ *mapped_blocks = 0;
+ if ((sbi->fat_bits != 32) && (inode->i_ino == MSDOS_ROOT_INO)) {
+ if (sector < (sbi->dir_entries >> sbi->dir_per_block_bits)) {
+ *phys = sector + sbi->dir_start;
+ *mapped_blocks = 1;
+ }
+ return 0;
+ }
+
+ if (!from_bmap) {
+ if (is_exceed_eof(inode, sector, &last_block, create))
+ return 0;
+ } else {
+ last_block = inode->i_blocks >>
+ (inode->i_sb->s_blocksize_bits - 9);
+ if (sector >= last_block)
+ return 0;
+ }
+
+ return fat_get_mapped_cluster(inode, sector, last_block, mapped_blocks,
+ phys);
+}
diff --git a/fs/fat/dir.c b/fs/fat/dir.c
new file mode 100644
index 0000000..7f5f369
--- /dev/null
+++ b/fs/fat/dir.c
@@ -0,0 +1,1408 @@
+/*
+ * linux/fs/fat/dir.c
+ *
+ * directory handling functions for fat-based filesystems
+ *
+ * Written 1992,1993 by Werner Almesberger
+ *
+ * Hidden files 1995 by Albert Cahalan <albert@ccs.neu.edu> <adc@coe.neu.edu>
+ *
+ * VFAT extensions by Gordon Chaffee <chaffee@plateau.cs.berkeley.edu>
+ * Merged with msdos fs by Henrik Storner <storner@osiris.ping.dk>
+ * Rewritten for constant inumbers. Plugged buffer overrun in readdir(). AV
+ * Short name translation 1999, 2001 by Wolfram Pienkoss <wp@bszh.de>
+ */
+
+#include <linux/slab.h>
+#include <linux/compat.h>
+#include <linux/uaccess.h>
+#include <linux/iversion.h>
+#include "fat.h"
+
+/*
+ * Maximum buffer size of short name.
+ * [(MSDOS_NAME + '.') * max one char + nul]
+ * For msdos style, ['.' (hidden) + MSDOS_NAME + '.' + nul]
+ */
+#define FAT_MAX_SHORT_SIZE ((MSDOS_NAME + 1) * NLS_MAX_CHARSET_SIZE + 1)
+/*
+ * Maximum buffer size of unicode chars from slots.
+ * [(max longname slots * 13 (size in a slot) + nul) * sizeof(wchar_t)]
+ */
+#define FAT_MAX_UNI_CHARS ((MSDOS_SLOTS - 1) * 13 + 1)
+#define FAT_MAX_UNI_SIZE (FAT_MAX_UNI_CHARS * sizeof(wchar_t))
+
+static inline unsigned char fat_tolower(unsigned char c)
+{
+ return ((c >= 'A') && (c <= 'Z')) ? c+32 : c;
+}
+
+static inline loff_t fat_make_i_pos(struct super_block *sb,
+ struct buffer_head *bh,
+ struct msdos_dir_entry *de)
+{
+ return ((loff_t)bh->b_blocknr << MSDOS_SB(sb)->dir_per_block_bits)
+ | (de - (struct msdos_dir_entry *)bh->b_data);
+}
+
+static inline void fat_dir_readahead(struct inode *dir, sector_t iblock,
+ sector_t phys)
+{
+ struct super_block *sb = dir->i_sb;
+ struct msdos_sb_info *sbi = MSDOS_SB(sb);
+ struct buffer_head *bh;
+ int sec;
+
+ /* This is not a first sector of cluster, or sec_per_clus == 1 */
+ if ((iblock & (sbi->sec_per_clus - 1)) || sbi->sec_per_clus == 1)
+ return;
+ /* root dir of FAT12/FAT16 */
+ if ((sbi->fat_bits != 32) && (dir->i_ino == MSDOS_ROOT_INO))
+ return;
+
+ bh = sb_find_get_block(sb, phys);
+ if (bh == NULL || !buffer_uptodate(bh)) {
+ for (sec = 0; sec < sbi->sec_per_clus; sec++)
+ sb_breadahead(sb, phys + sec);
+ }
+ brelse(bh);
+}
+
+/* Returns the inode number of the directory entry at offset pos. If bh is
+ non-NULL, it is brelse'd before. Pos is incremented. The buffer header is
+ returned in bh.
+ AV. Most often we do it item-by-item. Makes sense to optimize.
+ AV. OK, there we go: if both bh and de are non-NULL we assume that we just
+ AV. want the next entry (took one explicit de=NULL in vfat/namei.c).
+ AV. It's done in fat_get_entry() (inlined), here the slow case lives.
+ AV. Additionally, when we return -1 (i.e. reached the end of directory)
+ AV. we make bh NULL.
+ */
+static int fat__get_entry(struct inode *dir, loff_t *pos,
+ struct buffer_head **bh, struct msdos_dir_entry **de)
+{
+ struct super_block *sb = dir->i_sb;
+ sector_t phys, iblock;
+ unsigned long mapped_blocks;
+ int err, offset;
+
+next:
+ if (*bh)
+ brelse(*bh);
+
+ *bh = NULL;
+ iblock = *pos >> sb->s_blocksize_bits;
+ err = fat_bmap(dir, iblock, &phys, &mapped_blocks, 0, false);
+ if (err || !phys)
+ return -1; /* beyond EOF or error */
+
+ fat_dir_readahead(dir, iblock, phys);
+
+ *bh = sb_bread(sb, phys);
+ if (*bh == NULL) {
+ fat_msg_ratelimit(sb, KERN_ERR,
+ "Directory bread(block %llu) failed", (llu)phys);
+ /* skip this block */
+ *pos = (iblock + 1) << sb->s_blocksize_bits;
+ goto next;
+ }
+
+ offset = *pos & (sb->s_blocksize - 1);
+ *pos += sizeof(struct msdos_dir_entry);
+ *de = (struct msdos_dir_entry *)((*bh)->b_data + offset);
+
+ return 0;
+}
+
+static inline int fat_get_entry(struct inode *dir, loff_t *pos,
+ struct buffer_head **bh,
+ struct msdos_dir_entry **de)
+{
+ /* Fast stuff first */
+ if (*bh && *de &&
+ (*de - (struct msdos_dir_entry *)(*bh)->b_data) <
+ MSDOS_SB(dir->i_sb)->dir_per_block - 1) {
+ *pos += sizeof(struct msdos_dir_entry);
+ (*de)++;
+ return 0;
+ }
+ return fat__get_entry(dir, pos, bh, de);
+}
+
+/*
+ * Convert Unicode 16 to UTF-8, translated Unicode, or ASCII.
+ * If uni_xlate is enabled and we can't get a 1:1 conversion, use a
+ * colon as an escape character since it is normally invalid on the vfat
+ * filesystem. The following four characters are the hexadecimal digits
+ * of Unicode value. This lets us do a full dump and restore of Unicode
+ * filenames. We could get into some trouble with long Unicode names,
+ * but ignore that right now.
+ * Ahem... Stack smashing in ring 0 isn't fun. Fixed.
+ */
+static int uni16_to_x8(struct super_block *sb, unsigned char *ascii,
+ const wchar_t *uni, int len, struct nls_table *nls)
+{
+ int uni_xlate = MSDOS_SB(sb)->options.unicode_xlate;
+ const wchar_t *ip;
+ wchar_t ec;
+ unsigned char *op;
+ int charlen;
+
+ ip = uni;
+ op = ascii;
+
+ while (*ip && ((len - NLS_MAX_CHARSET_SIZE) > 0)) {
+ ec = *ip++;
+ charlen = nls->uni2char(ec, op, NLS_MAX_CHARSET_SIZE);
+ if (charlen > 0) {
+ op += charlen;
+ len -= charlen;
+ } else {
+ if (uni_xlate == 1) {
+ *op++ = ':';
+ op = hex_byte_pack(op, ec >> 8);
+ op = hex_byte_pack(op, ec);
+ len -= 5;
+ } else {
+ *op++ = '?';
+ len--;
+ }
+ }
+ }
+
+ if (unlikely(*ip)) {
+ fat_msg(sb, KERN_WARNING,
+ "filename was truncated while converting.");
+ }
+
+ *op = 0;
+ return op - ascii;
+}
+
+static inline int fat_uni_to_x8(struct super_block *sb, const wchar_t *uni,
+ unsigned char *buf, int size)
+{
+ struct msdos_sb_info *sbi = MSDOS_SB(sb);
+ if (sbi->options.utf8)
+ return utf16s_to_utf8s(uni, FAT_MAX_UNI_CHARS,
+ UTF16_HOST_ENDIAN, buf, size);
+ else
+ return uni16_to_x8(sb, buf, uni, size, sbi->nls_io);
+}
+
+static inline int
+fat_short2uni(struct nls_table *t, unsigned char *c, int clen, wchar_t *uni)
+{
+ int charlen;
+
+ charlen = t->char2uni(c, clen, uni);
+ if (charlen < 0) {
+ *uni = 0x003f; /* a question mark */
+ charlen = 1;
+ }
+ return charlen;
+}
+
+static inline int
+fat_short2lower_uni(struct nls_table *t, unsigned char *c,
+ int clen, wchar_t *uni)
+{
+ int charlen;
+ wchar_t wc;
+
+ charlen = t->char2uni(c, clen, &wc);
+ if (charlen < 0) {
+ *uni = 0x003f; /* a question mark */
+ charlen = 1;
+ } else if (charlen <= 1) {
+ unsigned char nc = t->charset2lower[*c];
+
+ if (!nc)
+ nc = *c;
+
+ charlen = t->char2uni(&nc, 1, uni);
+ if (charlen < 0) {
+ *uni = 0x003f; /* a question mark */
+ charlen = 1;
+ }
+ } else
+ *uni = wc;
+
+ return charlen;
+}
+
+static inline int
+fat_shortname2uni(struct nls_table *nls, unsigned char *buf, int buf_size,
+ wchar_t *uni_buf, unsigned short opt, int lower)
+{
+ int len = 0;
+
+ if (opt & VFAT_SFN_DISPLAY_LOWER)
+ len = fat_short2lower_uni(nls, buf, buf_size, uni_buf);
+ else if (opt & VFAT_SFN_DISPLAY_WIN95)
+ len = fat_short2uni(nls, buf, buf_size, uni_buf);
+ else if (opt & VFAT_SFN_DISPLAY_WINNT) {
+ if (lower)
+ len = fat_short2lower_uni(nls, buf, buf_size, uni_buf);
+ else
+ len = fat_short2uni(nls, buf, buf_size, uni_buf);
+ } else
+ len = fat_short2uni(nls, buf, buf_size, uni_buf);
+
+ return len;
+}
+
+static inline int fat_name_match(struct msdos_sb_info *sbi,
+ const unsigned char *a, int a_len,
+ const unsigned char *b, int b_len)
+{
+ if (a_len != b_len)
+ return 0;
+
+ if (sbi->options.name_check != 's')
+ return !nls_strnicmp(sbi->nls_io, a, b, a_len);
+ else
+ return !memcmp(a, b, a_len);
+}
+
+enum { PARSE_INVALID = 1, PARSE_NOT_LONGNAME, PARSE_EOF, };
+
+/**
+ * fat_parse_long - Parse extended directory entry.
+ *
+ * This function returns zero on success, negative value on error, or one of
+ * the following:
+ *
+ * %PARSE_INVALID - Directory entry is invalid.
+ * %PARSE_NOT_LONGNAME - Directory entry does not contain longname.
+ * %PARSE_EOF - Directory has no more entries.
+ */
+static int fat_parse_long(struct inode *dir, loff_t *pos,
+ struct buffer_head **bh, struct msdos_dir_entry **de,
+ wchar_t **unicode, unsigned char *nr_slots)
+{
+ struct msdos_dir_slot *ds;
+ unsigned char id, slot, slots, alias_checksum;
+
+ if (!*unicode) {
+ *unicode = __getname();
+ if (!*unicode) {
+ brelse(*bh);
+ return -ENOMEM;
+ }
+ }
+parse_long:
+ ds = (struct msdos_dir_slot *)*de;
+ id = ds->id;
+ if (!(id & 0x40))
+ return PARSE_INVALID;
+ slots = id & ~0x40;
+ if (slots > 20 || !slots) /* ceil(256 * 2 / 26) */
+ return PARSE_INVALID;
+ *nr_slots = slots;
+ alias_checksum = ds->alias_checksum;
+
+ slot = slots;
+ while (1) {
+ int offset;
+
+ slot--;
+ offset = slot * 13;
+ fat16_towchar(*unicode + offset, ds->name0_4, 5);
+ fat16_towchar(*unicode + offset + 5, ds->name5_10, 6);
+ fat16_towchar(*unicode + offset + 11, ds->name11_12, 2);
+
+ if (ds->id & 0x40)
+ (*unicode)[offset + 13] = 0;
+ if (fat_get_entry(dir, pos, bh, de) < 0)
+ return PARSE_EOF;
+ if (slot == 0)
+ break;
+ ds = (struct msdos_dir_slot *)*de;
+ if (ds->attr != ATTR_EXT)
+ return PARSE_NOT_LONGNAME;
+ if ((ds->id & ~0x40) != slot)
+ goto parse_long;
+ if (ds->alias_checksum != alias_checksum)
+ goto parse_long;
+ }
+ if ((*de)->name[0] == DELETED_FLAG)
+ return PARSE_INVALID;
+ if ((*de)->attr == ATTR_EXT)
+ goto parse_long;
+ if (IS_FREE((*de)->name) || ((*de)->attr & ATTR_VOLUME))
+ return PARSE_INVALID;
+ if (fat_checksum((*de)->name) != alias_checksum)
+ *nr_slots = 0;
+
+ return 0;
+}
+
+/**
+ * fat_parse_short - Parse MS-DOS (short) directory entry.
+ * @sb: superblock
+ * @de: directory entry to parse
+ * @name: FAT_MAX_SHORT_SIZE array in which to place extracted name
+ * @dot_hidden: Nonzero == prepend '.' to names with ATTR_HIDDEN
+ *
+ * Returns the number of characters extracted into 'name'.
+ */
+static int fat_parse_short(struct super_block *sb,
+ const struct msdos_dir_entry *de,
+ unsigned char *name, int dot_hidden)
+{
+ const struct msdos_sb_info *sbi = MSDOS_SB(sb);
+ int isvfat = sbi->options.isvfat;
+ int nocase = sbi->options.nocase;
+ unsigned short opt_shortname = sbi->options.shortname;
+ struct nls_table *nls_disk = sbi->nls_disk;
+ wchar_t uni_name[14];
+ unsigned char c, work[MSDOS_NAME];
+ unsigned char *ptname = name;
+ int chi, chl, i, j, k;
+ int dotoffset = 0;
+ int name_len = 0, uni_len = 0;
+
+ if (!isvfat && dot_hidden && (de->attr & ATTR_HIDDEN)) {
+ *ptname++ = '.';
+ dotoffset = 1;
+ }
+
+ memcpy(work, de->name, sizeof(work));
+ /* see namei.c, msdos_format_name */
+ if (work[0] == 0x05)
+ work[0] = 0xE5;
+
+ /* Filename */
+ for (i = 0, j = 0; i < 8;) {
+ c = work[i];
+ if (!c)
+ break;
+ chl = fat_shortname2uni(nls_disk, &work[i], 8 - i,
+ &uni_name[j++], opt_shortname,
+ de->lcase & CASE_LOWER_BASE);
+ if (chl <= 1) {
+ if (!isvfat)
+ ptname[i] = nocase ? c : fat_tolower(c);
+ i++;
+ if (c != ' ') {
+ name_len = i;
+ uni_len = j;
+ }
+ } else {
+ uni_len = j;
+ if (isvfat)
+ i += min(chl, 8-i);
+ else {
+ for (chi = 0; chi < chl && i < 8; chi++, i++)
+ ptname[i] = work[i];
+ }
+ if (chl)
+ name_len = i;
+ }
+ }
+
+ i = name_len;
+ j = uni_len;
+ fat_short2uni(nls_disk, ".", 1, &uni_name[j++]);
+ if (!isvfat)
+ ptname[i] = '.';
+ i++;
+
+ /* Extension */
+ for (k = 8; k < MSDOS_NAME;) {
+ c = work[k];
+ if (!c)
+ break;
+ chl = fat_shortname2uni(nls_disk, &work[k], MSDOS_NAME - k,
+ &uni_name[j++], opt_shortname,
+ de->lcase & CASE_LOWER_EXT);
+ if (chl <= 1) {
+ k++;
+ if (!isvfat)
+ ptname[i] = nocase ? c : fat_tolower(c);
+ i++;
+ if (c != ' ') {
+ name_len = i;
+ uni_len = j;
+ }
+ } else {
+ uni_len = j;
+ if (isvfat) {
+ int offset = min(chl, MSDOS_NAME-k);
+ k += offset;
+ i += offset;
+ } else {
+ for (chi = 0; chi < chl && k < MSDOS_NAME;
+ chi++, i++, k++) {
+ ptname[i] = work[k];
+ }
+ }
+ if (chl)
+ name_len = i;
+ }
+ }
+
+ if (name_len > 0) {
+ name_len += dotoffset;
+
+ if (sbi->options.isvfat) {
+ uni_name[uni_len] = 0x0000;
+ name_len = fat_uni_to_x8(sb, uni_name, name,
+ FAT_MAX_SHORT_SIZE);
+ }
+ }
+
+ return name_len;
+}
+
+/*
+ * Return values: negative -> error/not found, 0 -> found.
+ */
+int fat_search_long(struct inode *inode, const unsigned char *name,
+ int name_len, struct fat_slot_info *sinfo)
+{
+ struct super_block *sb = inode->i_sb;
+ struct msdos_sb_info *sbi = MSDOS_SB(sb);
+ struct buffer_head *bh = NULL;
+ struct msdos_dir_entry *de;
+ unsigned char nr_slots;
+ wchar_t *unicode = NULL;
+ unsigned char bufname[FAT_MAX_SHORT_SIZE];
+ loff_t cpos = 0;
+ int err, len;
+
+ err = -ENOENT;
+ while (1) {
+ if (fat_get_entry(inode, &cpos, &bh, &de) == -1)
+ goto end_of_dir;
+parse_record:
+ nr_slots = 0;
+ if (de->name[0] == DELETED_FLAG)
+ continue;
+ if (de->attr != ATTR_EXT && (de->attr & ATTR_VOLUME))
+ continue;
+ if (de->attr != ATTR_EXT && IS_FREE(de->name))
+ continue;
+ if (de->attr == ATTR_EXT) {
+ int status = fat_parse_long(inode, &cpos, &bh, &de,
+ &unicode, &nr_slots);
+ if (status < 0) {
+ err = status;
+ goto end_of_dir;
+ } else if (status == PARSE_INVALID)
+ continue;
+ else if (status == PARSE_NOT_LONGNAME)
+ goto parse_record;
+ else if (status == PARSE_EOF)
+ goto end_of_dir;
+ }
+
+ /* Never prepend '.' to hidden files here.
+ * That is done only for msdos mounts (and only when
+ * 'dotsOK=yes'); if we are executing here, it is in the
+ * context of a vfat mount.
+ */
+ len = fat_parse_short(sb, de, bufname, 0);
+ if (len == 0)
+ continue;
+
+ /* Compare shortname */
+ if (fat_name_match(sbi, name, name_len, bufname, len))
+ goto found;
+
+ if (nr_slots) {
+ void *longname = unicode + FAT_MAX_UNI_CHARS;
+ int size = PATH_MAX - FAT_MAX_UNI_SIZE;
+
+ /* Compare longname */
+ len = fat_uni_to_x8(sb, unicode, longname, size);
+ if (fat_name_match(sbi, name, name_len, longname, len))
+ goto found;
+ }
+ }
+
+found:
+ nr_slots++; /* include the de */
+ sinfo->slot_off = cpos - nr_slots * sizeof(*de);
+ sinfo->nr_slots = nr_slots;
+ sinfo->de = de;
+ sinfo->bh = bh;
+ sinfo->i_pos = fat_make_i_pos(sb, sinfo->bh, sinfo->de);
+ err = 0;
+end_of_dir:
+ if (unicode)
+ __putname(unicode);
+
+ return err;
+}
+EXPORT_SYMBOL_GPL(fat_search_long);
+
+struct fat_ioctl_filldir_callback {
+ struct dir_context ctx;
+ void __user *dirent;
+ int result;
+ /* for dir ioctl */
+ const char *longname;
+ int long_len;
+ const char *shortname;
+ int short_len;
+};
+
+static int __fat_readdir(struct inode *inode, struct file *file,
+ struct dir_context *ctx, int short_only,
+ struct fat_ioctl_filldir_callback *both)
+{
+ struct super_block *sb = inode->i_sb;
+ struct msdos_sb_info *sbi = MSDOS_SB(sb);
+ struct buffer_head *bh;
+ struct msdos_dir_entry *de;
+ unsigned char nr_slots;
+ wchar_t *unicode = NULL;
+ unsigned char bufname[FAT_MAX_SHORT_SIZE];
+ int isvfat = sbi->options.isvfat;
+ const char *fill_name = NULL;
+ int fake_offset = 0;
+ loff_t cpos;
+ int short_len = 0, fill_len = 0;
+ int ret = 0;
+
+ mutex_lock(&sbi->s_lock);
+
+ cpos = ctx->pos;
+ /* Fake . and .. for the root directory. */
+ if (inode->i_ino == MSDOS_ROOT_INO) {
+ if (!dir_emit_dots(file, ctx))
+ goto out;
+ if (ctx->pos == 2) {
+ fake_offset = 1;
+ cpos = 0;
+ }
+ }
+ if (cpos & (sizeof(struct msdos_dir_entry) - 1)) {
+ ret = -ENOENT;
+ goto out;
+ }
+
+ bh = NULL;
+get_new:
+ if (fat_get_entry(inode, &cpos, &bh, &de) == -1)
+ goto end_of_dir;
+parse_record:
+ nr_slots = 0;
+ /*
+ * Check for long filename entry, but if short_only, we don't
+ * need to parse long filename.
+ */
+ if (isvfat && !short_only) {
+ if (de->name[0] == DELETED_FLAG)
+ goto record_end;
+ if (de->attr != ATTR_EXT && (de->attr & ATTR_VOLUME))
+ goto record_end;
+ if (de->attr != ATTR_EXT && IS_FREE(de->name))
+ goto record_end;
+ } else {
+ if ((de->attr & ATTR_VOLUME) || IS_FREE(de->name))
+ goto record_end;
+ }
+
+ if (isvfat && de->attr == ATTR_EXT) {
+ int status = fat_parse_long(inode, &cpos, &bh, &de,
+ &unicode, &nr_slots);
+ if (status < 0) {
+ bh = NULL;
+ ret = status;
+ goto end_of_dir;
+ } else if (status == PARSE_INVALID)
+ goto record_end;
+ else if (status == PARSE_NOT_LONGNAME)
+ goto parse_record;
+ else if (status == PARSE_EOF)
+ goto end_of_dir;
+
+ if (nr_slots) {
+ void *longname = unicode + FAT_MAX_UNI_CHARS;
+ int size = PATH_MAX - FAT_MAX_UNI_SIZE;
+ int len = fat_uni_to_x8(sb, unicode, longname, size);
+
+ fill_name = longname;
+ fill_len = len;
+ /* !both && !short_only, so we don't need shortname. */
+ if (!both)
+ goto start_filldir;
+
+ short_len = fat_parse_short(sb, de, bufname,
+ sbi->options.dotsOK);
+ if (short_len == 0)
+ goto record_end;
+ /* hack for fat_ioctl_filldir() */
+ both->longname = fill_name;
+ both->long_len = fill_len;
+ both->shortname = bufname;
+ both->short_len = short_len;
+ fill_name = NULL;
+ fill_len = 0;
+ goto start_filldir;
+ }
+ }
+
+ short_len = fat_parse_short(sb, de, bufname, sbi->options.dotsOK);
+ if (short_len == 0)
+ goto record_end;
+
+ fill_name = bufname;
+ fill_len = short_len;
+
+start_filldir:
+ ctx->pos = cpos - (nr_slots + 1) * sizeof(struct msdos_dir_entry);
+ if (fake_offset && ctx->pos < 2)
+ ctx->pos = 2;
+
+ if (!memcmp(de->name, MSDOS_DOT, MSDOS_NAME)) {
+ if (!dir_emit_dot(file, ctx))
+ goto fill_failed;
+ } else if (!memcmp(de->name, MSDOS_DOTDOT, MSDOS_NAME)) {
+ if (!dir_emit_dotdot(file, ctx))
+ goto fill_failed;
+ } else {
+ unsigned long inum;
+ loff_t i_pos = fat_make_i_pos(sb, bh, de);
+ struct inode *tmp = fat_iget(sb, i_pos);
+ if (tmp) {
+ inum = tmp->i_ino;
+ iput(tmp);
+ } else
+ inum = iunique(sb, MSDOS_ROOT_INO);
+ if (!dir_emit(ctx, fill_name, fill_len, inum,
+ (de->attr & ATTR_DIR) ? DT_DIR : DT_REG))
+ goto fill_failed;
+ }
+
+record_end:
+ fake_offset = 0;
+ ctx->pos = cpos;
+ goto get_new;
+
+end_of_dir:
+ if (fake_offset && cpos < 2)
+ ctx->pos = 2;
+ else
+ ctx->pos = cpos;
+fill_failed:
+ brelse(bh);
+ if (unicode)
+ __putname(unicode);
+out:
+ mutex_unlock(&sbi->s_lock);
+
+ return ret;
+}
+
+static int fat_readdir(struct file *file, struct dir_context *ctx)
+{
+ return __fat_readdir(file_inode(file), file, ctx, 0, NULL);
+}
+
+#define FAT_IOCTL_FILLDIR_FUNC(func, dirent_type) \
+static int func(struct dir_context *ctx, const char *name, int name_len, \
+ loff_t offset, u64 ino, unsigned int d_type) \
+{ \
+ struct fat_ioctl_filldir_callback *buf = \
+ container_of(ctx, struct fat_ioctl_filldir_callback, ctx); \
+ struct dirent_type __user *d1 = buf->dirent; \
+ struct dirent_type __user *d2 = d1 + 1; \
+ \
+ if (buf->result) \
+ return -EINVAL; \
+ buf->result++; \
+ \
+ if (name != NULL) { \
+ /* dirent has only short name */ \
+ if (name_len >= sizeof(d1->d_name)) \
+ name_len = sizeof(d1->d_name) - 1; \
+ \
+ if (put_user(0, d2->d_name) || \
+ put_user(0, &d2->d_reclen) || \
+ copy_to_user(d1->d_name, name, name_len) || \
+ put_user(0, d1->d_name + name_len) || \
+ put_user(name_len, &d1->d_reclen)) \
+ goto efault; \
+ } else { \
+ /* dirent has short and long name */ \
+ const char *longname = buf->longname; \
+ int long_len = buf->long_len; \
+ const char *shortname = buf->shortname; \
+ int short_len = buf->short_len; \
+ \
+ if (long_len >= sizeof(d1->d_name)) \
+ long_len = sizeof(d1->d_name) - 1; \
+ if (short_len >= sizeof(d1->d_name)) \
+ short_len = sizeof(d1->d_name) - 1; \
+ \
+ if (copy_to_user(d2->d_name, longname, long_len) || \
+ put_user(0, d2->d_name + long_len) || \
+ put_user(long_len, &d2->d_reclen) || \
+ put_user(ino, &d2->d_ino) || \
+ put_user(offset, &d2->d_off) || \
+ copy_to_user(d1->d_name, shortname, short_len) || \
+ put_user(0, d1->d_name + short_len) || \
+ put_user(short_len, &d1->d_reclen)) \
+ goto efault; \
+ } \
+ return 0; \
+efault: \
+ buf->result = -EFAULT; \
+ return -EFAULT; \
+}
+
+FAT_IOCTL_FILLDIR_FUNC(fat_ioctl_filldir, __fat_dirent)
+
+static int fat_ioctl_readdir(struct inode *inode, struct file *file,
+ void __user *dirent, filldir_t filldir,
+ int short_only, int both)
+{
+ struct fat_ioctl_filldir_callback buf = {
+ .ctx.actor = filldir,
+ .dirent = dirent
+ };
+ int ret;
+
+ buf.dirent = dirent;
+ buf.result = 0;
+ inode_lock_shared(inode);
+ buf.ctx.pos = file->f_pos;
+ ret = -ENOENT;
+ if (!IS_DEADDIR(inode)) {
+ ret = __fat_readdir(inode, file, &buf.ctx,
+ short_only, both ? &buf : NULL);
+ file->f_pos = buf.ctx.pos;
+ }
+ inode_unlock_shared(inode);
+ if (ret >= 0)
+ ret = buf.result;
+ return ret;
+}
+
+static long fat_dir_ioctl(struct file *filp, unsigned int cmd,
+ unsigned long arg)
+{
+ struct inode *inode = file_inode(filp);
+ struct __fat_dirent __user *d1 = (struct __fat_dirent __user *)arg;
+ int short_only, both;
+
+ switch (cmd) {
+ case VFAT_IOCTL_READDIR_SHORT:
+ short_only = 1;
+ both = 0;
+ break;
+ case VFAT_IOCTL_READDIR_BOTH:
+ short_only = 0;
+ both = 1;
+ break;
+ default:
+ return fat_generic_ioctl(filp, cmd, arg);
+ }
+
+ if (!access_ok(VERIFY_WRITE, d1, sizeof(struct __fat_dirent[2])))
+ return -EFAULT;
+ /*
+ * Yes, we don't need this put_user() absolutely. However old
+ * code didn't return the right value. So, app use this value,
+ * in order to check whether it is EOF.
+ */
+ if (put_user(0, &d1->d_reclen))
+ return -EFAULT;
+
+ return fat_ioctl_readdir(inode, filp, d1, fat_ioctl_filldir,
+ short_only, both);
+}
+
+#ifdef CONFIG_COMPAT
+#define VFAT_IOCTL_READDIR_BOTH32 _IOR('r', 1, struct compat_dirent[2])
+#define VFAT_IOCTL_READDIR_SHORT32 _IOR('r', 2, struct compat_dirent[2])
+
+FAT_IOCTL_FILLDIR_FUNC(fat_compat_ioctl_filldir, compat_dirent)
+
+static long fat_compat_dir_ioctl(struct file *filp, unsigned cmd,
+ unsigned long arg)
+{
+ struct inode *inode = file_inode(filp);
+ struct compat_dirent __user *d1 = compat_ptr(arg);
+ int short_only, both;
+
+ switch (cmd) {
+ case VFAT_IOCTL_READDIR_SHORT32:
+ short_only = 1;
+ both = 0;
+ break;
+ case VFAT_IOCTL_READDIR_BOTH32:
+ short_only = 0;
+ both = 1;
+ break;
+ default:
+ return fat_generic_ioctl(filp, cmd, (unsigned long)arg);
+ }
+
+ if (!access_ok(VERIFY_WRITE, d1, sizeof(struct compat_dirent[2])))
+ return -EFAULT;
+ /*
+ * Yes, we don't need this put_user() absolutely. However old
+ * code didn't return the right value. So, app use this value,
+ * in order to check whether it is EOF.
+ */
+ if (put_user(0, &d1->d_reclen))
+ return -EFAULT;
+
+ return fat_ioctl_readdir(inode, filp, d1, fat_compat_ioctl_filldir,
+ short_only, both);
+}
+#endif /* CONFIG_COMPAT */
+
+const struct file_operations fat_dir_operations = {
+ .llseek = generic_file_llseek,
+ .read = generic_read_dir,
+ .iterate_shared = fat_readdir,
+ .unlocked_ioctl = fat_dir_ioctl,
+#ifdef CONFIG_COMPAT
+ .compat_ioctl = fat_compat_dir_ioctl,
+#endif
+ .fsync = fat_file_fsync,
+};
+
+static int fat_get_short_entry(struct inode *dir, loff_t *pos,
+ struct buffer_head **bh,
+ struct msdos_dir_entry **de)
+{
+ while (fat_get_entry(dir, pos, bh, de) >= 0) {
+ /* free entry or long name entry or volume label */
+ if (!IS_FREE((*de)->name) && !((*de)->attr & ATTR_VOLUME))
+ return 0;
+ }
+ return -ENOENT;
+}
+
+/*
+ * The ".." entry can not provide the "struct fat_slot_info" information
+ * for inode, nor a usable i_pos. So, this function provides some information
+ * only.
+ *
+ * Since this function walks through the on-disk inodes within a directory,
+ * callers are responsible for taking any locks necessary to prevent the
+ * directory from changing.
+ */
+int fat_get_dotdot_entry(struct inode *dir, struct buffer_head **bh,
+ struct msdos_dir_entry **de)
+{
+ loff_t offset = 0;
+
+ *de = NULL;
+ while (fat_get_short_entry(dir, &offset, bh, de) >= 0) {
+ if (!strncmp((*de)->name, MSDOS_DOTDOT, MSDOS_NAME))
+ return 0;
+ }
+ return -ENOENT;
+}
+EXPORT_SYMBOL_GPL(fat_get_dotdot_entry);
+
+/* See if directory is empty */
+int fat_dir_empty(struct inode *dir)
+{
+ struct buffer_head *bh;
+ struct msdos_dir_entry *de;
+ loff_t cpos;
+ int result = 0;
+
+ bh = NULL;
+ cpos = 0;
+ while (fat_get_short_entry(dir, &cpos, &bh, &de) >= 0) {
+ if (strncmp(de->name, MSDOS_DOT , MSDOS_NAME) &&
+ strncmp(de->name, MSDOS_DOTDOT, MSDOS_NAME)) {
+ result = -ENOTEMPTY;
+ break;
+ }
+ }
+ brelse(bh);
+ return result;
+}
+EXPORT_SYMBOL_GPL(fat_dir_empty);
+
+/*
+ * fat_subdirs counts the number of sub-directories of dir. It can be run
+ * on directories being created.
+ */
+int fat_subdirs(struct inode *dir)
+{
+ struct buffer_head *bh;
+ struct msdos_dir_entry *de;
+ loff_t cpos;
+ int count = 0;
+
+ bh = NULL;
+ cpos = 0;
+ while (fat_get_short_entry(dir, &cpos, &bh, &de) >= 0) {
+ if (de->attr & ATTR_DIR)
+ count++;
+ }
+ brelse(bh);
+ return count;
+}
+
+/*
+ * Scans a directory for a given file (name points to its formatted name).
+ * Returns an error code or zero.
+ */
+int fat_scan(struct inode *dir, const unsigned char *name,
+ struct fat_slot_info *sinfo)
+{
+ struct super_block *sb = dir->i_sb;
+
+ sinfo->slot_off = 0;
+ sinfo->bh = NULL;
+ while (fat_get_short_entry(dir, &sinfo->slot_off, &sinfo->bh,
+ &sinfo->de) >= 0) {
+ if (!strncmp(sinfo->de->name, name, MSDOS_NAME)) {
+ sinfo->slot_off -= sizeof(*sinfo->de);
+ sinfo->nr_slots = 1;
+ sinfo->i_pos = fat_make_i_pos(sb, sinfo->bh, sinfo->de);
+ return 0;
+ }
+ }
+ return -ENOENT;
+}
+EXPORT_SYMBOL_GPL(fat_scan);
+
+/*
+ * Scans a directory for a given logstart.
+ * Returns an error code or zero.
+ */
+int fat_scan_logstart(struct inode *dir, int i_logstart,
+ struct fat_slot_info *sinfo)
+{
+ struct super_block *sb = dir->i_sb;
+
+ sinfo->slot_off = 0;
+ sinfo->bh = NULL;
+ while (fat_get_short_entry(dir, &sinfo->slot_off, &sinfo->bh,
+ &sinfo->de) >= 0) {
+ if (fat_get_start(MSDOS_SB(sb), sinfo->de) == i_logstart) {
+ sinfo->slot_off -= sizeof(*sinfo->de);
+ sinfo->nr_slots = 1;
+ sinfo->i_pos = fat_make_i_pos(sb, sinfo->bh, sinfo->de);
+ return 0;
+ }
+ }
+ return -ENOENT;
+}
+
+static int __fat_remove_entries(struct inode *dir, loff_t pos, int nr_slots)
+{
+ struct super_block *sb = dir->i_sb;
+ struct buffer_head *bh;
+ struct msdos_dir_entry *de, *endp;
+ int err = 0, orig_slots;
+
+ while (nr_slots) {
+ bh = NULL;
+ if (fat_get_entry(dir, &pos, &bh, &de) < 0) {
+ err = -EIO;
+ break;
+ }
+
+ orig_slots = nr_slots;
+ endp = (struct msdos_dir_entry *)(bh->b_data + sb->s_blocksize);
+ while (nr_slots && de < endp) {
+ de->name[0] = DELETED_FLAG;
+ de++;
+ nr_slots--;
+ }
+ mark_buffer_dirty_inode(bh, dir);
+ if (IS_DIRSYNC(dir))
+ err = sync_dirty_buffer(bh);
+ brelse(bh);
+ if (err)
+ break;
+
+ /* pos is *next* de's position, so this does `- sizeof(de)' */
+ pos += ((orig_slots - nr_slots) * sizeof(*de)) - sizeof(*de);
+ }
+
+ return err;
+}
+
+int fat_remove_entries(struct inode *dir, struct fat_slot_info *sinfo)
+{
+ struct super_block *sb = dir->i_sb;
+ struct msdos_dir_entry *de;
+ struct buffer_head *bh;
+ int err = 0, nr_slots;
+
+ /*
+ * First stage: Remove the shortname. By this, the directory
+ * entry is removed.
+ */
+ nr_slots = sinfo->nr_slots;
+ de = sinfo->de;
+ sinfo->de = NULL;
+ bh = sinfo->bh;
+ sinfo->bh = NULL;
+ while (nr_slots && de >= (struct msdos_dir_entry *)bh->b_data) {
+ de->name[0] = DELETED_FLAG;
+ de--;
+ nr_slots--;
+ }
+ mark_buffer_dirty_inode(bh, dir);
+ if (IS_DIRSYNC(dir))
+ err = sync_dirty_buffer(bh);
+ brelse(bh);
+ if (err)
+ return err;
+ inode_inc_iversion(dir);
+
+ if (nr_slots) {
+ /*
+ * Second stage: remove the remaining longname slots.
+ * (This directory entry is already removed, and so return
+ * the success)
+ */
+ err = __fat_remove_entries(dir, sinfo->slot_off, nr_slots);
+ if (err) {
+ fat_msg(sb, KERN_WARNING,
+ "Couldn't remove the long name slots");
+ }
+ }
+
+ dir->i_mtime = dir->i_atime = current_time(dir);
+ if (IS_DIRSYNC(dir))
+ (void)fat_sync_inode(dir);
+ else
+ mark_inode_dirty(dir);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(fat_remove_entries);
+
+static int fat_zeroed_cluster(struct inode *dir, sector_t blknr, int nr_used,
+ struct buffer_head **bhs, int nr_bhs)
+{
+ struct super_block *sb = dir->i_sb;
+ sector_t last_blknr = blknr + MSDOS_SB(sb)->sec_per_clus;
+ int err, i, n;
+
+ /* Zeroing the unused blocks on this cluster */
+ blknr += nr_used;
+ n = nr_used;
+ while (blknr < last_blknr) {
+ bhs[n] = sb_getblk(sb, blknr);
+ if (!bhs[n]) {
+ err = -ENOMEM;
+ goto error;
+ }
+ memset(bhs[n]->b_data, 0, sb->s_blocksize);
+ set_buffer_uptodate(bhs[n]);
+ mark_buffer_dirty_inode(bhs[n], dir);
+
+ n++;
+ blknr++;
+ if (n == nr_bhs) {
+ if (IS_DIRSYNC(dir)) {
+ err = fat_sync_bhs(bhs, n);
+ if (err)
+ goto error;
+ }
+ for (i = 0; i < n; i++)
+ brelse(bhs[i]);
+ n = 0;
+ }
+ }
+ if (IS_DIRSYNC(dir)) {
+ err = fat_sync_bhs(bhs, n);
+ if (err)
+ goto error;
+ }
+ for (i = 0; i < n; i++)
+ brelse(bhs[i]);
+
+ return 0;
+
+error:
+ for (i = 0; i < n; i++)
+ bforget(bhs[i]);
+ return err;
+}
+
+int fat_alloc_new_dir(struct inode *dir, struct timespec64 *ts)
+{
+ struct super_block *sb = dir->i_sb;
+ struct msdos_sb_info *sbi = MSDOS_SB(sb);
+ struct buffer_head *bhs[MAX_BUF_PER_PAGE];
+ struct msdos_dir_entry *de;
+ sector_t blknr;
+ __le16 date, time;
+ u8 time_cs;
+ int err, cluster;
+
+ err = fat_alloc_clusters(dir, &cluster, 1);
+ if (err)
+ goto error;
+
+ blknr = fat_clus_to_blknr(sbi, cluster);
+ bhs[0] = sb_getblk(sb, blknr);
+ if (!bhs[0]) {
+ err = -ENOMEM;
+ goto error_free;
+ }
+
+ fat_time_unix2fat(sbi, ts, &time, &date, &time_cs);
+
+ de = (struct msdos_dir_entry *)bhs[0]->b_data;
+ /* filling the new directory slots ("." and ".." entries) */
+ memcpy(de[0].name, MSDOS_DOT, MSDOS_NAME);
+ memcpy(de[1].name, MSDOS_DOTDOT, MSDOS_NAME);
+ de->attr = de[1].attr = ATTR_DIR;
+ de[0].lcase = de[1].lcase = 0;
+ de[0].time = de[1].time = time;
+ de[0].date = de[1].date = date;
+ if (sbi->options.isvfat) {
+ /* extra timestamps */
+ de[0].ctime = de[1].ctime = time;
+ de[0].ctime_cs = de[1].ctime_cs = time_cs;
+ de[0].adate = de[0].cdate = de[1].adate = de[1].cdate = date;
+ } else {
+ de[0].ctime = de[1].ctime = 0;
+ de[0].ctime_cs = de[1].ctime_cs = 0;
+ de[0].adate = de[0].cdate = de[1].adate = de[1].cdate = 0;
+ }
+ fat_set_start(&de[0], cluster);
+ fat_set_start(&de[1], MSDOS_I(dir)->i_logstart);
+ de[0].size = de[1].size = 0;
+ memset(de + 2, 0, sb->s_blocksize - 2 * sizeof(*de));
+ set_buffer_uptodate(bhs[0]);
+ mark_buffer_dirty_inode(bhs[0], dir);
+
+ err = fat_zeroed_cluster(dir, blknr, 1, bhs, MAX_BUF_PER_PAGE);
+ if (err)
+ goto error_free;
+
+ return cluster;
+
+error_free:
+ fat_free_clusters(dir, cluster);
+error:
+ return err;
+}
+EXPORT_SYMBOL_GPL(fat_alloc_new_dir);
+
+static int fat_add_new_entries(struct inode *dir, void *slots, int nr_slots,
+ int *nr_cluster, struct msdos_dir_entry **de,
+ struct buffer_head **bh, loff_t *i_pos)
+{
+ struct super_block *sb = dir->i_sb;
+ struct msdos_sb_info *sbi = MSDOS_SB(sb);
+ struct buffer_head *bhs[MAX_BUF_PER_PAGE];
+ sector_t blknr, start_blknr, last_blknr;
+ unsigned long size, copy;
+ int err, i, n, offset, cluster[2];
+
+ /*
+ * The minimum cluster size is 512bytes, and maximum entry
+ * size is 32*slots (672bytes). So, iff the cluster size is
+ * 512bytes, we may need two clusters.
+ */
+ size = nr_slots * sizeof(struct msdos_dir_entry);
+ *nr_cluster = (size + (sbi->cluster_size - 1)) >> sbi->cluster_bits;
+ BUG_ON(*nr_cluster > 2);
+
+ err = fat_alloc_clusters(dir, cluster, *nr_cluster);
+ if (err)
+ goto error;
+
+ /*
+ * First stage: Fill the directory entry. NOTE: This cluster
+ * is not referenced from any inode yet, so updates order is
+ * not important.
+ */
+ i = n = copy = 0;
+ do {
+ start_blknr = blknr = fat_clus_to_blknr(sbi, cluster[i]);
+ last_blknr = start_blknr + sbi->sec_per_clus;
+ while (blknr < last_blknr) {
+ bhs[n] = sb_getblk(sb, blknr);
+ if (!bhs[n]) {
+ err = -ENOMEM;
+ goto error_nomem;
+ }
+
+ /* fill the directory entry */
+ copy = min(size, sb->s_blocksize);
+ memcpy(bhs[n]->b_data, slots, copy);
+ slots += copy;
+ size -= copy;
+ set_buffer_uptodate(bhs[n]);
+ mark_buffer_dirty_inode(bhs[n], dir);
+ if (!size)
+ break;
+ n++;
+ blknr++;
+ }
+ } while (++i < *nr_cluster);
+
+ memset(bhs[n]->b_data + copy, 0, sb->s_blocksize - copy);
+ offset = copy - sizeof(struct msdos_dir_entry);
+ get_bh(bhs[n]);
+ *bh = bhs[n];
+ *de = (struct msdos_dir_entry *)((*bh)->b_data + offset);
+ *i_pos = fat_make_i_pos(sb, *bh, *de);
+
+ /* Second stage: clear the rest of cluster, and write outs */
+ err = fat_zeroed_cluster(dir, start_blknr, ++n, bhs, MAX_BUF_PER_PAGE);
+ if (err)
+ goto error_free;
+
+ return cluster[0];
+
+error_free:
+ brelse(*bh);
+ *bh = NULL;
+ n = 0;
+error_nomem:
+ for (i = 0; i < n; i++)
+ bforget(bhs[i]);
+ fat_free_clusters(dir, cluster[0]);
+error:
+ return err;
+}
+
+int fat_add_entries(struct inode *dir, void *slots, int nr_slots,
+ struct fat_slot_info *sinfo)
+{
+ struct super_block *sb = dir->i_sb;
+ struct msdos_sb_info *sbi = MSDOS_SB(sb);
+ struct buffer_head *bh, *prev, *bhs[3]; /* 32*slots (672bytes) */
+ struct msdos_dir_entry *uninitialized_var(de);
+ int err, free_slots, i, nr_bhs;
+ loff_t pos, i_pos;
+
+ sinfo->nr_slots = nr_slots;
+
+ /* First stage: search free directory entries */
+ free_slots = nr_bhs = 0;
+ bh = prev = NULL;
+ pos = 0;
+ err = -ENOSPC;
+ while (fat_get_entry(dir, &pos, &bh, &de) > -1) {
+ /* check the maximum size of directory */
+ if (pos >= FAT_MAX_DIR_SIZE)
+ goto error;
+
+ if (IS_FREE(de->name)) {
+ if (prev != bh) {
+ get_bh(bh);
+ bhs[nr_bhs] = prev = bh;
+ nr_bhs++;
+ }
+ free_slots++;
+ if (free_slots == nr_slots)
+ goto found;
+ } else {
+ for (i = 0; i < nr_bhs; i++)
+ brelse(bhs[i]);
+ prev = NULL;
+ free_slots = nr_bhs = 0;
+ }
+ }
+ if (dir->i_ino == MSDOS_ROOT_INO) {
+ if (sbi->fat_bits != 32)
+ goto error;
+ } else if (MSDOS_I(dir)->i_start == 0) {
+ fat_msg(sb, KERN_ERR, "Corrupted directory (i_pos %lld)",
+ MSDOS_I(dir)->i_pos);
+ err = -EIO;
+ goto error;
+ }
+
+found:
+ err = 0;
+ pos -= free_slots * sizeof(*de);
+ nr_slots -= free_slots;
+ if (free_slots) {
+ /*
+ * Second stage: filling the free entries with new entries.
+ * NOTE: If this slots has shortname, first, we write
+ * the long name slots, then write the short name.
+ */
+ int size = free_slots * sizeof(*de);
+ int offset = pos & (sb->s_blocksize - 1);
+ int long_bhs = nr_bhs - (nr_slots == 0);
+
+ /* Fill the long name slots. */
+ for (i = 0; i < long_bhs; i++) {
+ int copy = min_t(int, sb->s_blocksize - offset, size);
+ memcpy(bhs[i]->b_data + offset, slots, copy);
+ mark_buffer_dirty_inode(bhs[i], dir);
+ offset = 0;
+ slots += copy;
+ size -= copy;
+ }
+ if (long_bhs && IS_DIRSYNC(dir))
+ err = fat_sync_bhs(bhs, long_bhs);
+ if (!err && i < nr_bhs) {
+ /* Fill the short name slot. */
+ int copy = min_t(int, sb->s_blocksize - offset, size);
+ memcpy(bhs[i]->b_data + offset, slots, copy);
+ mark_buffer_dirty_inode(bhs[i], dir);
+ if (IS_DIRSYNC(dir))
+ err = sync_dirty_buffer(bhs[i]);
+ }
+ for (i = 0; i < nr_bhs; i++)
+ brelse(bhs[i]);
+ if (err)
+ goto error_remove;
+ }
+
+ if (nr_slots) {
+ int cluster, nr_cluster;
+
+ /*
+ * Third stage: allocate the cluster for new entries.
+ * And initialize the cluster with new entries, then
+ * add the cluster to dir.
+ */
+ cluster = fat_add_new_entries(dir, slots, nr_slots, &nr_cluster,
+ &de, &bh, &i_pos);
+ if (cluster < 0) {
+ err = cluster;
+ goto error_remove;
+ }
+ err = fat_chain_add(dir, cluster, nr_cluster);
+ if (err) {
+ fat_free_clusters(dir, cluster);
+ goto error_remove;
+ }
+ if (dir->i_size & (sbi->cluster_size - 1)) {
+ fat_fs_error(sb, "Odd directory size");
+ dir->i_size = (dir->i_size + sbi->cluster_size - 1)
+ & ~((loff_t)sbi->cluster_size - 1);
+ }
+ dir->i_size += nr_cluster << sbi->cluster_bits;
+ MSDOS_I(dir)->mmu_private += nr_cluster << sbi->cluster_bits;
+ }
+ sinfo->slot_off = pos;
+ sinfo->de = de;
+ sinfo->bh = bh;
+ sinfo->i_pos = fat_make_i_pos(sb, sinfo->bh, sinfo->de);
+
+ return 0;
+
+error:
+ brelse(bh);
+ for (i = 0; i < nr_bhs; i++)
+ brelse(bhs[i]);
+ return err;
+
+error_remove:
+ brelse(bh);
+ if (free_slots)
+ __fat_remove_entries(dir, pos, free_slots);
+ return err;
+}
+EXPORT_SYMBOL_GPL(fat_add_entries);
diff --git a/fs/fat/fat.h b/fs/fat/fat.h
new file mode 100644
index 0000000..9d7d2d5
--- /dev/null
+++ b/fs/fat/fat.h
@@ -0,0 +1,431 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _FAT_H
+#define _FAT_H
+
+#include <linux/buffer_head.h>
+#include <linux/nls.h>
+#include <linux/hash.h>
+#include <linux/ratelimit.h>
+#include <linux/msdos_fs.h>
+
+/*
+ * vfat shortname flags
+ */
+#define VFAT_SFN_DISPLAY_LOWER 0x0001 /* convert to lowercase for display */
+#define VFAT_SFN_DISPLAY_WIN95 0x0002 /* emulate win95 rule for display */
+#define VFAT_SFN_DISPLAY_WINNT 0x0004 /* emulate winnt rule for display */
+#define VFAT_SFN_CREATE_WIN95 0x0100 /* emulate win95 rule for create */
+#define VFAT_SFN_CREATE_WINNT 0x0200 /* emulate winnt rule for create */
+
+#define FAT_ERRORS_CONT 1 /* ignore error and continue */
+#define FAT_ERRORS_PANIC 2 /* panic on error */
+#define FAT_ERRORS_RO 3 /* remount r/o on error */
+
+#define FAT_NFS_STALE_RW 1 /* NFS RW support, can cause ESTALE */
+#define FAT_NFS_NOSTALE_RO 2 /* NFS RO support, no ESTALE issue */
+
+struct fat_mount_options {
+ kuid_t fs_uid;
+ kgid_t fs_gid;
+ unsigned short fs_fmask;
+ unsigned short fs_dmask;
+ unsigned short codepage; /* Codepage for shortname conversions */
+ int time_offset; /* Offset of timestamps from UTC (in minutes) */
+ char *iocharset; /* Charset used for filename input/display */
+ unsigned short shortname; /* flags for shortname display/create rule */
+ unsigned char name_check; /* r = relaxed, n = normal, s = strict */
+ unsigned char errors; /* On error: continue, panic, remount-ro */
+ unsigned char nfs; /* NFS support: nostale_ro, stale_rw */
+ unsigned short allow_utime;/* permission for setting the [am]time */
+ unsigned quiet:1, /* set = fake successful chmods and chowns */
+ showexec:1, /* set = only set x bit for com/exe/bat */
+ sys_immutable:1, /* set = system files are immutable */
+ dotsOK:1, /* set = hidden and system files are named '.filename' */
+ isvfat:1, /* 0=no vfat long filename support, 1=vfat support */
+ utf8:1, /* Use of UTF-8 character set (Default) */
+ unicode_xlate:1, /* create escape sequences for unhandled Unicode */
+ numtail:1, /* Does first alias have a numeric '~1' type tail? */
+ flush:1, /* write things quickly */
+ nocase:1, /* Does this need case conversion? 0=need case conversion*/
+ usefree:1, /* Use free_clusters for FAT32 */
+ tz_set:1, /* Filesystem timestamps' offset set */
+ rodir:1, /* allow ATTR_RO for directory */
+ discard:1, /* Issue discard requests on deletions */
+ dos1xfloppy:1; /* Assume default BPB for DOS 1.x floppies */
+};
+
+#define FAT_HASH_BITS 8
+#define FAT_HASH_SIZE (1UL << FAT_HASH_BITS)
+
+/*
+ * MS-DOS file system in-core superblock data
+ */
+struct msdos_sb_info {
+ unsigned short sec_per_clus; /* sectors/cluster */
+ unsigned short cluster_bits; /* log2(cluster_size) */
+ unsigned int cluster_size; /* cluster size */
+ unsigned char fats, fat_bits; /* number of FATs, FAT bits (12,16 or 32) */
+ unsigned short fat_start;
+ unsigned long fat_length; /* FAT start & length (sec.) */
+ unsigned long dir_start;
+ unsigned short dir_entries; /* root dir start & entries */
+ unsigned long data_start; /* first data sector */
+ unsigned long max_cluster; /* maximum cluster number */
+ unsigned long root_cluster; /* first cluster of the root directory */
+ unsigned long fsinfo_sector; /* sector number of FAT32 fsinfo */
+ struct mutex fat_lock;
+ struct mutex nfs_build_inode_lock;
+ struct mutex s_lock;
+ unsigned int prev_free; /* previously allocated cluster number */
+ unsigned int free_clusters; /* -1 if undefined */
+ unsigned int free_clus_valid; /* is free_clusters valid? */
+ struct fat_mount_options options;
+ struct nls_table *nls_disk; /* Codepage used on disk */
+ struct nls_table *nls_io; /* Charset used for input and display */
+ const void *dir_ops; /* Opaque; default directory operations */
+ int dir_per_block; /* dir entries per block */
+ int dir_per_block_bits; /* log2(dir_per_block) */
+ unsigned int vol_id; /*volume ID*/
+
+ int fatent_shift;
+ const struct fatent_operations *fatent_ops;
+ struct inode *fat_inode;
+ struct inode *fsinfo_inode;
+
+ struct ratelimit_state ratelimit;
+
+ spinlock_t inode_hash_lock;
+ struct hlist_head inode_hashtable[FAT_HASH_SIZE];
+
+ spinlock_t dir_hash_lock;
+ struct hlist_head dir_hashtable[FAT_HASH_SIZE];
+
+ unsigned int dirty; /* fs state before mount */
+ struct rcu_head rcu;
+};
+
+#define FAT_CACHE_VALID 0 /* special case for valid cache */
+
+/*
+ * MS-DOS file system inode data in memory
+ */
+struct msdos_inode_info {
+ spinlock_t cache_lru_lock;
+ struct list_head cache_lru;
+ int nr_caches;
+ /* for avoiding the race between fat_free() and fat_get_cluster() */
+ unsigned int cache_valid_id;
+
+ /* NOTE: mmu_private is 64bits, so must hold ->i_mutex to access */
+ loff_t mmu_private; /* physically allocated size */
+
+ int i_start; /* first cluster or 0 */
+ int i_logstart; /* logical first cluster */
+ int i_attrs; /* unused attribute bits */
+ loff_t i_pos; /* on-disk position of directory entry or 0 */
+ struct hlist_node i_fat_hash; /* hash by i_location */
+ struct hlist_node i_dir_hash; /* hash by i_logstart */
+ struct rw_semaphore truncate_lock; /* protect bmap against truncate */
+ struct inode vfs_inode;
+};
+
+struct fat_slot_info {
+ loff_t i_pos; /* on-disk position of directory entry */
+ loff_t slot_off; /* offset for slot or de start */
+ int nr_slots; /* number of slots + 1(de) in filename */
+ struct msdos_dir_entry *de;
+ struct buffer_head *bh;
+};
+
+static inline struct msdos_sb_info *MSDOS_SB(struct super_block *sb)
+{
+ return sb->s_fs_info;
+}
+
+static inline struct msdos_inode_info *MSDOS_I(struct inode *inode)
+{
+ return container_of(inode, struct msdos_inode_info, vfs_inode);
+}
+
+/*
+ * If ->i_mode can't hold S_IWUGO (i.e. ATTR_RO), we use ->i_attrs to
+ * save ATTR_RO instead of ->i_mode.
+ *
+ * If it's directory and !sbi->options.rodir, ATTR_RO isn't read-only
+ * bit, it's just used as flag for app.
+ */
+static inline int fat_mode_can_hold_ro(struct inode *inode)
+{
+ struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
+ umode_t mask;
+
+ if (S_ISDIR(inode->i_mode)) {
+ if (!sbi->options.rodir)
+ return 0;
+ mask = ~sbi->options.fs_dmask;
+ } else
+ mask = ~sbi->options.fs_fmask;
+
+ if (!(mask & S_IWUGO))
+ return 0;
+ return 1;
+}
+
+/* Convert attribute bits and a mask to the UNIX mode. */
+static inline umode_t fat_make_mode(struct msdos_sb_info *sbi,
+ u8 attrs, umode_t mode)
+{
+ if (attrs & ATTR_RO && !((attrs & ATTR_DIR) && !sbi->options.rodir))
+ mode &= ~S_IWUGO;
+
+ if (attrs & ATTR_DIR)
+ return (mode & ~sbi->options.fs_dmask) | S_IFDIR;
+ else
+ return (mode & ~sbi->options.fs_fmask) | S_IFREG;
+}
+
+/* Return the FAT attribute byte for this inode */
+static inline u8 fat_make_attrs(struct inode *inode)
+{
+ u8 attrs = MSDOS_I(inode)->i_attrs;
+ if (S_ISDIR(inode->i_mode))
+ attrs |= ATTR_DIR;
+ if (fat_mode_can_hold_ro(inode) && !(inode->i_mode & S_IWUGO))
+ attrs |= ATTR_RO;
+ return attrs;
+}
+
+static inline void fat_save_attrs(struct inode *inode, u8 attrs)
+{
+ if (fat_mode_can_hold_ro(inode))
+ MSDOS_I(inode)->i_attrs = attrs & ATTR_UNUSED;
+ else
+ MSDOS_I(inode)->i_attrs = attrs & (ATTR_UNUSED | ATTR_RO);
+}
+
+static inline unsigned char fat_checksum(const __u8 *name)
+{
+ unsigned char s = name[0];
+ s = (s<<7) + (s>>1) + name[1]; s = (s<<7) + (s>>1) + name[2];
+ s = (s<<7) + (s>>1) + name[3]; s = (s<<7) + (s>>1) + name[4];
+ s = (s<<7) + (s>>1) + name[5]; s = (s<<7) + (s>>1) + name[6];
+ s = (s<<7) + (s>>1) + name[7]; s = (s<<7) + (s>>1) + name[8];
+ s = (s<<7) + (s>>1) + name[9]; s = (s<<7) + (s>>1) + name[10];
+ return s;
+}
+
+static inline sector_t fat_clus_to_blknr(struct msdos_sb_info *sbi, int clus)
+{
+ return ((sector_t)clus - FAT_START_ENT) * sbi->sec_per_clus
+ + sbi->data_start;
+}
+
+static inline void fat_get_blknr_offset(struct msdos_sb_info *sbi,
+ loff_t i_pos, sector_t *blknr, int *offset)
+{
+ *blknr = i_pos >> sbi->dir_per_block_bits;
+ *offset = i_pos & (sbi->dir_per_block - 1);
+}
+
+static inline loff_t fat_i_pos_read(struct msdos_sb_info *sbi,
+ struct inode *inode)
+{
+ loff_t i_pos;
+#if BITS_PER_LONG == 32
+ spin_lock(&sbi->inode_hash_lock);
+#endif
+ i_pos = MSDOS_I(inode)->i_pos;
+#if BITS_PER_LONG == 32
+ spin_unlock(&sbi->inode_hash_lock);
+#endif
+ return i_pos;
+}
+
+static inline void fat16_towchar(wchar_t *dst, const __u8 *src, size_t len)
+{
+#ifdef __BIG_ENDIAN
+ while (len--) {
+ *dst++ = src[0] | (src[1] << 8);
+ src += 2;
+ }
+#else
+ memcpy(dst, src, len * 2);
+#endif
+}
+
+static inline int fat_get_start(const struct msdos_sb_info *sbi,
+ const struct msdos_dir_entry *de)
+{
+ int cluster = le16_to_cpu(de->start);
+ if (sbi->fat_bits == 32)
+ cluster |= (le16_to_cpu(de->starthi) << 16);
+ return cluster;
+}
+
+static inline void fat_set_start(struct msdos_dir_entry *de, int cluster)
+{
+ de->start = cpu_to_le16(cluster);
+ de->starthi = cpu_to_le16(cluster >> 16);
+}
+
+static inline void fatwchar_to16(__u8 *dst, const wchar_t *src, size_t len)
+{
+#ifdef __BIG_ENDIAN
+ while (len--) {
+ dst[0] = *src & 0x00FF;
+ dst[1] = (*src & 0xFF00) >> 8;
+ dst += 2;
+ src++;
+ }
+#else
+ memcpy(dst, src, len * 2);
+#endif
+}
+
+/* fat/cache.c */
+extern void fat_cache_inval_inode(struct inode *inode);
+extern int fat_get_cluster(struct inode *inode, int cluster,
+ int *fclus, int *dclus);
+extern int fat_get_mapped_cluster(struct inode *inode, sector_t sector,
+ sector_t last_block,
+ unsigned long *mapped_blocks, sector_t *bmap);
+extern int fat_bmap(struct inode *inode, sector_t sector, sector_t *phys,
+ unsigned long *mapped_blocks, int create, bool from_bmap);
+
+/* fat/dir.c */
+extern const struct file_operations fat_dir_operations;
+extern int fat_search_long(struct inode *inode, const unsigned char *name,
+ int name_len, struct fat_slot_info *sinfo);
+extern int fat_dir_empty(struct inode *dir);
+extern int fat_subdirs(struct inode *dir);
+extern int fat_scan(struct inode *dir, const unsigned char *name,
+ struct fat_slot_info *sinfo);
+extern int fat_scan_logstart(struct inode *dir, int i_logstart,
+ struct fat_slot_info *sinfo);
+extern int fat_get_dotdot_entry(struct inode *dir, struct buffer_head **bh,
+ struct msdos_dir_entry **de);
+extern int fat_alloc_new_dir(struct inode *dir, struct timespec64 *ts);
+extern int fat_add_entries(struct inode *dir, void *slots, int nr_slots,
+ struct fat_slot_info *sinfo);
+extern int fat_remove_entries(struct inode *dir, struct fat_slot_info *sinfo);
+
+/* fat/fatent.c */
+struct fat_entry {
+ int entry;
+ union {
+ u8 *ent12_p[2];
+ __le16 *ent16_p;
+ __le32 *ent32_p;
+ } u;
+ int nr_bhs;
+ struct buffer_head *bhs[2];
+ struct inode *fat_inode;
+};
+
+static inline void fatent_init(struct fat_entry *fatent)
+{
+ fatent->nr_bhs = 0;
+ fatent->entry = 0;
+ fatent->u.ent32_p = NULL;
+ fatent->bhs[0] = fatent->bhs[1] = NULL;
+ fatent->fat_inode = NULL;
+}
+
+static inline void fatent_set_entry(struct fat_entry *fatent, int entry)
+{
+ fatent->entry = entry;
+ fatent->u.ent32_p = NULL;
+}
+
+static inline void fatent_brelse(struct fat_entry *fatent)
+{
+ int i;
+ fatent->u.ent32_p = NULL;
+ for (i = 0; i < fatent->nr_bhs; i++)
+ brelse(fatent->bhs[i]);
+ fatent->nr_bhs = 0;
+ fatent->bhs[0] = fatent->bhs[1] = NULL;
+ fatent->fat_inode = NULL;
+}
+
+static inline bool fat_valid_entry(struct msdos_sb_info *sbi, int entry)
+{
+ return FAT_START_ENT <= entry && entry < sbi->max_cluster;
+}
+
+extern void fat_ent_access_init(struct super_block *sb);
+extern int fat_ent_read(struct inode *inode, struct fat_entry *fatent,
+ int entry);
+extern int fat_ent_write(struct inode *inode, struct fat_entry *fatent,
+ int new, int wait);
+extern int fat_alloc_clusters(struct inode *inode, int *cluster,
+ int nr_cluster);
+extern int fat_free_clusters(struct inode *inode, int cluster);
+extern int fat_count_free_clusters(struct super_block *sb);
+extern int fat_trim_fs(struct inode *inode, struct fstrim_range *range);
+
+/* fat/file.c */
+extern long fat_generic_ioctl(struct file *filp, unsigned int cmd,
+ unsigned long arg);
+extern const struct file_operations fat_file_operations;
+extern const struct inode_operations fat_file_inode_operations;
+extern int fat_setattr(struct dentry *dentry, struct iattr *attr);
+extern void fat_truncate_blocks(struct inode *inode, loff_t offset);
+extern int fat_getattr(const struct path *path, struct kstat *stat,
+ u32 request_mask, unsigned int flags);
+extern int fat_file_fsync(struct file *file, loff_t start, loff_t end,
+ int datasync);
+
+/* fat/inode.c */
+extern int fat_block_truncate_page(struct inode *inode, loff_t from);
+extern void fat_attach(struct inode *inode, loff_t i_pos);
+extern void fat_detach(struct inode *inode);
+extern struct inode *fat_iget(struct super_block *sb, loff_t i_pos);
+extern struct inode *fat_build_inode(struct super_block *sb,
+ struct msdos_dir_entry *de, loff_t i_pos);
+extern int fat_sync_inode(struct inode *inode);
+extern int fat_fill_super(struct super_block *sb, void *data, int silent,
+ int isvfat, void (*setup)(struct super_block *));
+extern int fat_fill_inode(struct inode *inode, struct msdos_dir_entry *de);
+
+extern int fat_flush_inodes(struct super_block *sb, struct inode *i1,
+ struct inode *i2);
+static inline unsigned long fat_dir_hash(int logstart)
+{
+ return hash_32(logstart, FAT_HASH_BITS);
+}
+extern int fat_add_cluster(struct inode *inode);
+
+/* fat/misc.c */
+extern __printf(3, 4) __cold
+void __fat_fs_error(struct super_block *sb, int report, const char *fmt, ...);
+#define fat_fs_error(sb, fmt, args...) \
+ __fat_fs_error(sb, 1, fmt , ## args)
+#define fat_fs_error_ratelimit(sb, fmt, args...) \
+ __fat_fs_error(sb, __ratelimit(&MSDOS_SB(sb)->ratelimit), fmt , ## args)
+__printf(3, 4) __cold
+void fat_msg(struct super_block *sb, const char *level, const char *fmt, ...);
+#define fat_msg_ratelimit(sb, level, fmt, args...) \
+ do { \
+ if (__ratelimit(&MSDOS_SB(sb)->ratelimit)) \
+ fat_msg(sb, level, fmt, ## args); \
+ } while (0)
+extern int fat_clusters_flush(struct super_block *sb);
+extern int fat_chain_add(struct inode *inode, int new_dclus, int nr_cluster);
+extern void fat_time_fat2unix(struct msdos_sb_info *sbi, struct timespec64 *ts,
+ __le16 __time, __le16 __date, u8 time_cs);
+extern void fat_time_unix2fat(struct msdos_sb_info *sbi, struct timespec64 *ts,
+ __le16 *time, __le16 *date, u8 *time_cs);
+extern int fat_sync_bhs(struct buffer_head **bhs, int nr_bhs);
+
+int fat_cache_init(void);
+void fat_cache_destroy(void);
+
+/* fat/nfs.c */
+extern const struct export_operations fat_export_ops;
+extern const struct export_operations fat_export_ops_nostale;
+
+/* helper for printk */
+typedef unsigned long long llu;
+
+#endif /* !_FAT_H */
diff --git a/fs/fat/fatent.c b/fs/fat/fatent.c
new file mode 100644
index 0000000..f58c0ca
--- /dev/null
+++ b/fs/fat/fatent.c
@@ -0,0 +1,795 @@
+/*
+ * Copyright (C) 2004, OGAWA Hirofumi
+ * Released under GPL v2.
+ */
+
+#include <linux/blkdev.h>
+#include <linux/sched/signal.h>
+#include "fat.h"
+
+struct fatent_operations {
+ void (*ent_blocknr)(struct super_block *, int, int *, sector_t *);
+ void (*ent_set_ptr)(struct fat_entry *, int);
+ int (*ent_bread)(struct super_block *, struct fat_entry *,
+ int, sector_t);
+ int (*ent_get)(struct fat_entry *);
+ void (*ent_put)(struct fat_entry *, int);
+ int (*ent_next)(struct fat_entry *);
+};
+
+static DEFINE_SPINLOCK(fat12_entry_lock);
+
+static void fat12_ent_blocknr(struct super_block *sb, int entry,
+ int *offset, sector_t *blocknr)
+{
+ struct msdos_sb_info *sbi = MSDOS_SB(sb);
+ int bytes = entry + (entry >> 1);
+ WARN_ON(!fat_valid_entry(sbi, entry));
+ *offset = bytes & (sb->s_blocksize - 1);
+ *blocknr = sbi->fat_start + (bytes >> sb->s_blocksize_bits);
+}
+
+static void fat_ent_blocknr(struct super_block *sb, int entry,
+ int *offset, sector_t *blocknr)
+{
+ struct msdos_sb_info *sbi = MSDOS_SB(sb);
+ int bytes = (entry << sbi->fatent_shift);
+ WARN_ON(!fat_valid_entry(sbi, entry));
+ *offset = bytes & (sb->s_blocksize - 1);
+ *blocknr = sbi->fat_start + (bytes >> sb->s_blocksize_bits);
+}
+
+static void fat12_ent_set_ptr(struct fat_entry *fatent, int offset)
+{
+ struct buffer_head **bhs = fatent->bhs;
+ if (fatent->nr_bhs == 1) {
+ WARN_ON(offset >= (bhs[0]->b_size - 1));
+ fatent->u.ent12_p[0] = bhs[0]->b_data + offset;
+ fatent->u.ent12_p[1] = bhs[0]->b_data + (offset + 1);
+ } else {
+ WARN_ON(offset != (bhs[0]->b_size - 1));
+ fatent->u.ent12_p[0] = bhs[0]->b_data + offset;
+ fatent->u.ent12_p[1] = bhs[1]->b_data;
+ }
+}
+
+static void fat16_ent_set_ptr(struct fat_entry *fatent, int offset)
+{
+ WARN_ON(offset & (2 - 1));
+ fatent->u.ent16_p = (__le16 *)(fatent->bhs[0]->b_data + offset);
+}
+
+static void fat32_ent_set_ptr(struct fat_entry *fatent, int offset)
+{
+ WARN_ON(offset & (4 - 1));
+ fatent->u.ent32_p = (__le32 *)(fatent->bhs[0]->b_data + offset);
+}
+
+static int fat12_ent_bread(struct super_block *sb, struct fat_entry *fatent,
+ int offset, sector_t blocknr)
+{
+ struct buffer_head **bhs = fatent->bhs;
+
+ WARN_ON(blocknr < MSDOS_SB(sb)->fat_start);
+ fatent->fat_inode = MSDOS_SB(sb)->fat_inode;
+
+ bhs[0] = sb_bread(sb, blocknr);
+ if (!bhs[0])
+ goto err;
+
+ if ((offset + 1) < sb->s_blocksize)
+ fatent->nr_bhs = 1;
+ else {
+ /* This entry is block boundary, it needs the next block */
+ blocknr++;
+ bhs[1] = sb_bread(sb, blocknr);
+ if (!bhs[1])
+ goto err_brelse;
+ fatent->nr_bhs = 2;
+ }
+ fat12_ent_set_ptr(fatent, offset);
+ return 0;
+
+err_brelse:
+ brelse(bhs[0]);
+err:
+ fat_msg(sb, KERN_ERR, "FAT read failed (blocknr %llu)", (llu)blocknr);
+ return -EIO;
+}
+
+static int fat_ent_bread(struct super_block *sb, struct fat_entry *fatent,
+ int offset, sector_t blocknr)
+{
+ const struct fatent_operations *ops = MSDOS_SB(sb)->fatent_ops;
+
+ WARN_ON(blocknr < MSDOS_SB(sb)->fat_start);
+ fatent->fat_inode = MSDOS_SB(sb)->fat_inode;
+ fatent->bhs[0] = sb_bread(sb, blocknr);
+ if (!fatent->bhs[0]) {
+ fat_msg(sb, KERN_ERR, "FAT read failed (blocknr %llu)",
+ (llu)blocknr);
+ return -EIO;
+ }
+ fatent->nr_bhs = 1;
+ ops->ent_set_ptr(fatent, offset);
+ return 0;
+}
+
+static int fat12_ent_get(struct fat_entry *fatent)
+{
+ u8 **ent12_p = fatent->u.ent12_p;
+ int next;
+
+ spin_lock(&fat12_entry_lock);
+ if (fatent->entry & 1)
+ next = (*ent12_p[0] >> 4) | (*ent12_p[1] << 4);
+ else
+ next = (*ent12_p[1] << 8) | *ent12_p[0];
+ spin_unlock(&fat12_entry_lock);
+
+ next &= 0x0fff;
+ if (next >= BAD_FAT12)
+ next = FAT_ENT_EOF;
+ return next;
+}
+
+static int fat16_ent_get(struct fat_entry *fatent)
+{
+ int next = le16_to_cpu(*fatent->u.ent16_p);
+ WARN_ON((unsigned long)fatent->u.ent16_p & (2 - 1));
+ if (next >= BAD_FAT16)
+ next = FAT_ENT_EOF;
+ return next;
+}
+
+static int fat32_ent_get(struct fat_entry *fatent)
+{
+ int next = le32_to_cpu(*fatent->u.ent32_p) & 0x0fffffff;
+ WARN_ON((unsigned long)fatent->u.ent32_p & (4 - 1));
+ if (next >= BAD_FAT32)
+ next = FAT_ENT_EOF;
+ return next;
+}
+
+static void fat12_ent_put(struct fat_entry *fatent, int new)
+{
+ u8 **ent12_p = fatent->u.ent12_p;
+
+ if (new == FAT_ENT_EOF)
+ new = EOF_FAT12;
+
+ spin_lock(&fat12_entry_lock);
+ if (fatent->entry & 1) {
+ *ent12_p[0] = (new << 4) | (*ent12_p[0] & 0x0f);
+ *ent12_p[1] = new >> 4;
+ } else {
+ *ent12_p[0] = new & 0xff;
+ *ent12_p[1] = (*ent12_p[1] & 0xf0) | (new >> 8);
+ }
+ spin_unlock(&fat12_entry_lock);
+
+ mark_buffer_dirty_inode(fatent->bhs[0], fatent->fat_inode);
+ if (fatent->nr_bhs == 2)
+ mark_buffer_dirty_inode(fatent->bhs[1], fatent->fat_inode);
+}
+
+static void fat16_ent_put(struct fat_entry *fatent, int new)
+{
+ if (new == FAT_ENT_EOF)
+ new = EOF_FAT16;
+
+ *fatent->u.ent16_p = cpu_to_le16(new);
+ mark_buffer_dirty_inode(fatent->bhs[0], fatent->fat_inode);
+}
+
+static void fat32_ent_put(struct fat_entry *fatent, int new)
+{
+ WARN_ON(new & 0xf0000000);
+ new |= le32_to_cpu(*fatent->u.ent32_p) & ~0x0fffffff;
+ *fatent->u.ent32_p = cpu_to_le32(new);
+ mark_buffer_dirty_inode(fatent->bhs[0], fatent->fat_inode);
+}
+
+static int fat12_ent_next(struct fat_entry *fatent)
+{
+ u8 **ent12_p = fatent->u.ent12_p;
+ struct buffer_head **bhs = fatent->bhs;
+ u8 *nextp = ent12_p[1] + 1 + (fatent->entry & 1);
+
+ fatent->entry++;
+ if (fatent->nr_bhs == 1) {
+ WARN_ON(ent12_p[0] > (u8 *)(bhs[0]->b_data +
+ (bhs[0]->b_size - 2)));
+ WARN_ON(ent12_p[1] > (u8 *)(bhs[0]->b_data +
+ (bhs[0]->b_size - 1)));
+ if (nextp < (u8 *)(bhs[0]->b_data + (bhs[0]->b_size - 1))) {
+ ent12_p[0] = nextp - 1;
+ ent12_p[1] = nextp;
+ return 1;
+ }
+ } else {
+ WARN_ON(ent12_p[0] != (u8 *)(bhs[0]->b_data +
+ (bhs[0]->b_size - 1)));
+ WARN_ON(ent12_p[1] != (u8 *)bhs[1]->b_data);
+ ent12_p[0] = nextp - 1;
+ ent12_p[1] = nextp;
+ brelse(bhs[0]);
+ bhs[0] = bhs[1];
+ fatent->nr_bhs = 1;
+ return 1;
+ }
+ ent12_p[0] = NULL;
+ ent12_p[1] = NULL;
+ return 0;
+}
+
+static int fat16_ent_next(struct fat_entry *fatent)
+{
+ const struct buffer_head *bh = fatent->bhs[0];
+ fatent->entry++;
+ if (fatent->u.ent16_p < (__le16 *)(bh->b_data + (bh->b_size - 2))) {
+ fatent->u.ent16_p++;
+ return 1;
+ }
+ fatent->u.ent16_p = NULL;
+ return 0;
+}
+
+static int fat32_ent_next(struct fat_entry *fatent)
+{
+ const struct buffer_head *bh = fatent->bhs[0];
+ fatent->entry++;
+ if (fatent->u.ent32_p < (__le32 *)(bh->b_data + (bh->b_size - 4))) {
+ fatent->u.ent32_p++;
+ return 1;
+ }
+ fatent->u.ent32_p = NULL;
+ return 0;
+}
+
+static const struct fatent_operations fat12_ops = {
+ .ent_blocknr = fat12_ent_blocknr,
+ .ent_set_ptr = fat12_ent_set_ptr,
+ .ent_bread = fat12_ent_bread,
+ .ent_get = fat12_ent_get,
+ .ent_put = fat12_ent_put,
+ .ent_next = fat12_ent_next,
+};
+
+static const struct fatent_operations fat16_ops = {
+ .ent_blocknr = fat_ent_blocknr,
+ .ent_set_ptr = fat16_ent_set_ptr,
+ .ent_bread = fat_ent_bread,
+ .ent_get = fat16_ent_get,
+ .ent_put = fat16_ent_put,
+ .ent_next = fat16_ent_next,
+};
+
+static const struct fatent_operations fat32_ops = {
+ .ent_blocknr = fat_ent_blocknr,
+ .ent_set_ptr = fat32_ent_set_ptr,
+ .ent_bread = fat_ent_bread,
+ .ent_get = fat32_ent_get,
+ .ent_put = fat32_ent_put,
+ .ent_next = fat32_ent_next,
+};
+
+static inline void lock_fat(struct msdos_sb_info *sbi)
+{
+ mutex_lock(&sbi->fat_lock);
+}
+
+static inline void unlock_fat(struct msdos_sb_info *sbi)
+{
+ mutex_unlock(&sbi->fat_lock);
+}
+
+void fat_ent_access_init(struct super_block *sb)
+{
+ struct msdos_sb_info *sbi = MSDOS_SB(sb);
+
+ mutex_init(&sbi->fat_lock);
+
+ switch (sbi->fat_bits) {
+ case 32:
+ sbi->fatent_shift = 2;
+ sbi->fatent_ops = &fat32_ops;
+ break;
+ case 16:
+ sbi->fatent_shift = 1;
+ sbi->fatent_ops = &fat16_ops;
+ break;
+ case 12:
+ sbi->fatent_shift = -1;
+ sbi->fatent_ops = &fat12_ops;
+ break;
+ }
+}
+
+static void mark_fsinfo_dirty(struct super_block *sb)
+{
+ struct msdos_sb_info *sbi = MSDOS_SB(sb);
+
+ if (sb_rdonly(sb) || sbi->fat_bits != 32)
+ return;
+
+ __mark_inode_dirty(sbi->fsinfo_inode, I_DIRTY_SYNC);
+}
+
+static inline int fat_ent_update_ptr(struct super_block *sb,
+ struct fat_entry *fatent,
+ int offset, sector_t blocknr)
+{
+ struct msdos_sb_info *sbi = MSDOS_SB(sb);
+ const struct fatent_operations *ops = sbi->fatent_ops;
+ struct buffer_head **bhs = fatent->bhs;
+
+ /* Is this fatent's blocks including this entry? */
+ if (!fatent->nr_bhs || bhs[0]->b_blocknr != blocknr)
+ return 0;
+ if (sbi->fat_bits == 12) {
+ if ((offset + 1) < sb->s_blocksize) {
+ /* This entry is on bhs[0]. */
+ if (fatent->nr_bhs == 2) {
+ brelse(bhs[1]);
+ fatent->nr_bhs = 1;
+ }
+ } else {
+ /* This entry needs the next block. */
+ if (fatent->nr_bhs != 2)
+ return 0;
+ if (bhs[1]->b_blocknr != (blocknr + 1))
+ return 0;
+ }
+ }
+ ops->ent_set_ptr(fatent, offset);
+ return 1;
+}
+
+int fat_ent_read(struct inode *inode, struct fat_entry *fatent, int entry)
+{
+ struct super_block *sb = inode->i_sb;
+ struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
+ const struct fatent_operations *ops = sbi->fatent_ops;
+ int err, offset;
+ sector_t blocknr;
+
+ if (!fat_valid_entry(sbi, entry)) {
+ fatent_brelse(fatent);
+ fat_fs_error(sb, "invalid access to FAT (entry 0x%08x)", entry);
+ return -EIO;
+ }
+
+ fatent_set_entry(fatent, entry);
+ ops->ent_blocknr(sb, entry, &offset, &blocknr);
+
+ if (!fat_ent_update_ptr(sb, fatent, offset, blocknr)) {
+ fatent_brelse(fatent);
+ err = ops->ent_bread(sb, fatent, offset, blocknr);
+ if (err)
+ return err;
+ }
+ return ops->ent_get(fatent);
+}
+
+/* FIXME: We can write the blocks as more big chunk. */
+static int fat_mirror_bhs(struct super_block *sb, struct buffer_head **bhs,
+ int nr_bhs)
+{
+ struct msdos_sb_info *sbi = MSDOS_SB(sb);
+ struct buffer_head *c_bh;
+ int err, n, copy;
+
+ err = 0;
+ for (copy = 1; copy < sbi->fats; copy++) {
+ sector_t backup_fat = sbi->fat_length * copy;
+
+ for (n = 0; n < nr_bhs; n++) {
+ c_bh = sb_getblk(sb, backup_fat + bhs[n]->b_blocknr);
+ if (!c_bh) {
+ err = -ENOMEM;
+ goto error;
+ }
+ memcpy(c_bh->b_data, bhs[n]->b_data, sb->s_blocksize);
+ set_buffer_uptodate(c_bh);
+ mark_buffer_dirty_inode(c_bh, sbi->fat_inode);
+ if (sb->s_flags & SB_SYNCHRONOUS)
+ err = sync_dirty_buffer(c_bh);
+ brelse(c_bh);
+ if (err)
+ goto error;
+ }
+ }
+error:
+ return err;
+}
+
+int fat_ent_write(struct inode *inode, struct fat_entry *fatent,
+ int new, int wait)
+{
+ struct super_block *sb = inode->i_sb;
+ const struct fatent_operations *ops = MSDOS_SB(sb)->fatent_ops;
+ int err;
+
+ ops->ent_put(fatent, new);
+ if (wait) {
+ err = fat_sync_bhs(fatent->bhs, fatent->nr_bhs);
+ if (err)
+ return err;
+ }
+ return fat_mirror_bhs(sb, fatent->bhs, fatent->nr_bhs);
+}
+
+static inline int fat_ent_next(struct msdos_sb_info *sbi,
+ struct fat_entry *fatent)
+{
+ if (sbi->fatent_ops->ent_next(fatent)) {
+ if (fatent->entry < sbi->max_cluster)
+ return 1;
+ }
+ return 0;
+}
+
+static inline int fat_ent_read_block(struct super_block *sb,
+ struct fat_entry *fatent)
+{
+ const struct fatent_operations *ops = MSDOS_SB(sb)->fatent_ops;
+ sector_t blocknr;
+ int offset;
+
+ fatent_brelse(fatent);
+ ops->ent_blocknr(sb, fatent->entry, &offset, &blocknr);
+ return ops->ent_bread(sb, fatent, offset, blocknr);
+}
+
+static void fat_collect_bhs(struct buffer_head **bhs, int *nr_bhs,
+ struct fat_entry *fatent)
+{
+ int n, i;
+
+ for (n = 0; n < fatent->nr_bhs; n++) {
+ for (i = 0; i < *nr_bhs; i++) {
+ if (fatent->bhs[n] == bhs[i])
+ break;
+ }
+ if (i == *nr_bhs) {
+ get_bh(fatent->bhs[n]);
+ bhs[i] = fatent->bhs[n];
+ (*nr_bhs)++;
+ }
+ }
+}
+
+int fat_alloc_clusters(struct inode *inode, int *cluster, int nr_cluster)
+{
+ struct super_block *sb = inode->i_sb;
+ struct msdos_sb_info *sbi = MSDOS_SB(sb);
+ const struct fatent_operations *ops = sbi->fatent_ops;
+ struct fat_entry fatent, prev_ent;
+ struct buffer_head *bhs[MAX_BUF_PER_PAGE];
+ int i, count, err, nr_bhs, idx_clus;
+
+ BUG_ON(nr_cluster > (MAX_BUF_PER_PAGE / 2)); /* fixed limit */
+
+ lock_fat(sbi);
+ if (sbi->free_clusters != -1 && sbi->free_clus_valid &&
+ sbi->free_clusters < nr_cluster) {
+ unlock_fat(sbi);
+ return -ENOSPC;
+ }
+
+ err = nr_bhs = idx_clus = 0;
+ count = FAT_START_ENT;
+ fatent_init(&prev_ent);
+ fatent_init(&fatent);
+ fatent_set_entry(&fatent, sbi->prev_free + 1);
+ while (count < sbi->max_cluster) {
+ if (fatent.entry >= sbi->max_cluster)
+ fatent.entry = FAT_START_ENT;
+ fatent_set_entry(&fatent, fatent.entry);
+ err = fat_ent_read_block(sb, &fatent);
+ if (err)
+ goto out;
+
+ /* Find the free entries in a block */
+ do {
+ if (ops->ent_get(&fatent) == FAT_ENT_FREE) {
+ int entry = fatent.entry;
+
+ /* make the cluster chain */
+ ops->ent_put(&fatent, FAT_ENT_EOF);
+ if (prev_ent.nr_bhs)
+ ops->ent_put(&prev_ent, entry);
+
+ fat_collect_bhs(bhs, &nr_bhs, &fatent);
+
+ sbi->prev_free = entry;
+ if (sbi->free_clusters != -1)
+ sbi->free_clusters--;
+
+ cluster[idx_clus] = entry;
+ idx_clus++;
+ if (idx_clus == nr_cluster)
+ goto out;
+
+ /*
+ * fat_collect_bhs() gets ref-count of bhs,
+ * so we can still use the prev_ent.
+ */
+ prev_ent = fatent;
+ }
+ count++;
+ if (count == sbi->max_cluster)
+ break;
+ } while (fat_ent_next(sbi, &fatent));
+ }
+
+ /* Couldn't allocate the free entries */
+ sbi->free_clusters = 0;
+ sbi->free_clus_valid = 1;
+ err = -ENOSPC;
+
+out:
+ unlock_fat(sbi);
+ mark_fsinfo_dirty(sb);
+ fatent_brelse(&fatent);
+ if (!err) {
+ if (inode_needs_sync(inode))
+ err = fat_sync_bhs(bhs, nr_bhs);
+ if (!err)
+ err = fat_mirror_bhs(sb, bhs, nr_bhs);
+ }
+ for (i = 0; i < nr_bhs; i++)
+ brelse(bhs[i]);
+
+ if (err && idx_clus)
+ fat_free_clusters(inode, cluster[0]);
+
+ return err;
+}
+
+int fat_free_clusters(struct inode *inode, int cluster)
+{
+ struct super_block *sb = inode->i_sb;
+ struct msdos_sb_info *sbi = MSDOS_SB(sb);
+ const struct fatent_operations *ops = sbi->fatent_ops;
+ struct fat_entry fatent;
+ struct buffer_head *bhs[MAX_BUF_PER_PAGE];
+ int i, err, nr_bhs;
+ int first_cl = cluster, dirty_fsinfo = 0;
+
+ nr_bhs = 0;
+ fatent_init(&fatent);
+ lock_fat(sbi);
+ do {
+ cluster = fat_ent_read(inode, &fatent, cluster);
+ if (cluster < 0) {
+ err = cluster;
+ goto error;
+ } else if (cluster == FAT_ENT_FREE) {
+ fat_fs_error(sb, "%s: deleting FAT entry beyond EOF",
+ __func__);
+ err = -EIO;
+ goto error;
+ }
+
+ if (sbi->options.discard) {
+ /*
+ * Issue discard for the sectors we no longer
+ * care about, batching contiguous clusters
+ * into one request
+ */
+ if (cluster != fatent.entry + 1) {
+ int nr_clus = fatent.entry - first_cl + 1;
+
+ sb_issue_discard(sb,
+ fat_clus_to_blknr(sbi, first_cl),
+ nr_clus * sbi->sec_per_clus,
+ GFP_NOFS, 0);
+
+ first_cl = cluster;
+ }
+ }
+
+ ops->ent_put(&fatent, FAT_ENT_FREE);
+ if (sbi->free_clusters != -1) {
+ sbi->free_clusters++;
+ dirty_fsinfo = 1;
+ }
+
+ if (nr_bhs + fatent.nr_bhs > MAX_BUF_PER_PAGE) {
+ if (sb->s_flags & SB_SYNCHRONOUS) {
+ err = fat_sync_bhs(bhs, nr_bhs);
+ if (err)
+ goto error;
+ }
+ err = fat_mirror_bhs(sb, bhs, nr_bhs);
+ if (err)
+ goto error;
+ for (i = 0; i < nr_bhs; i++)
+ brelse(bhs[i]);
+ nr_bhs = 0;
+ }
+ fat_collect_bhs(bhs, &nr_bhs, &fatent);
+ } while (cluster != FAT_ENT_EOF);
+
+ if (sb->s_flags & SB_SYNCHRONOUS) {
+ err = fat_sync_bhs(bhs, nr_bhs);
+ if (err)
+ goto error;
+ }
+ err = fat_mirror_bhs(sb, bhs, nr_bhs);
+error:
+ fatent_brelse(&fatent);
+ for (i = 0; i < nr_bhs; i++)
+ brelse(bhs[i]);
+ unlock_fat(sbi);
+ if (dirty_fsinfo)
+ mark_fsinfo_dirty(sb);
+
+ return err;
+}
+EXPORT_SYMBOL_GPL(fat_free_clusters);
+
+/* 128kb is the whole sectors for FAT12 and FAT16 */
+#define FAT_READA_SIZE (128 * 1024)
+
+static void fat_ent_reada(struct super_block *sb, struct fat_entry *fatent,
+ unsigned long reada_blocks)
+{
+ const struct fatent_operations *ops = MSDOS_SB(sb)->fatent_ops;
+ sector_t blocknr;
+ int i, offset;
+
+ ops->ent_blocknr(sb, fatent->entry, &offset, &blocknr);
+
+ for (i = 0; i < reada_blocks; i++)
+ sb_breadahead(sb, blocknr + i);
+}
+
+int fat_count_free_clusters(struct super_block *sb)
+{
+ struct msdos_sb_info *sbi = MSDOS_SB(sb);
+ const struct fatent_operations *ops = sbi->fatent_ops;
+ struct fat_entry fatent;
+ unsigned long reada_blocks, reada_mask, cur_block;
+ int err = 0, free;
+
+ lock_fat(sbi);
+ if (sbi->free_clusters != -1 && sbi->free_clus_valid)
+ goto out;
+
+ reada_blocks = FAT_READA_SIZE >> sb->s_blocksize_bits;
+ reada_mask = reada_blocks - 1;
+ cur_block = 0;
+
+ free = 0;
+ fatent_init(&fatent);
+ fatent_set_entry(&fatent, FAT_START_ENT);
+ while (fatent.entry < sbi->max_cluster) {
+ /* readahead of fat blocks */
+ if ((cur_block & reada_mask) == 0) {
+ unsigned long rest = sbi->fat_length - cur_block;
+ fat_ent_reada(sb, &fatent, min(reada_blocks, rest));
+ }
+ cur_block++;
+
+ err = fat_ent_read_block(sb, &fatent);
+ if (err)
+ goto out;
+
+ do {
+ if (ops->ent_get(&fatent) == FAT_ENT_FREE)
+ free++;
+ } while (fat_ent_next(sbi, &fatent));
+ cond_resched();
+ }
+ sbi->free_clusters = free;
+ sbi->free_clus_valid = 1;
+ mark_fsinfo_dirty(sb);
+ fatent_brelse(&fatent);
+out:
+ unlock_fat(sbi);
+ return err;
+}
+
+static int fat_trim_clusters(struct super_block *sb, u32 clus, u32 nr_clus)
+{
+ struct msdos_sb_info *sbi = MSDOS_SB(sb);
+ return sb_issue_discard(sb, fat_clus_to_blknr(sbi, clus),
+ nr_clus * sbi->sec_per_clus, GFP_NOFS, 0);
+}
+
+int fat_trim_fs(struct inode *inode, struct fstrim_range *range)
+{
+ struct super_block *sb = inode->i_sb;
+ struct msdos_sb_info *sbi = MSDOS_SB(sb);
+ const struct fatent_operations *ops = sbi->fatent_ops;
+ struct fat_entry fatent;
+ u64 ent_start, ent_end, minlen, trimmed = 0;
+ u32 free = 0;
+ unsigned long reada_blocks, reada_mask, cur_block = 0;
+ int err = 0;
+
+ /*
+ * FAT data is organized as clusters, trim at the granulary of cluster.
+ *
+ * fstrim_range is in byte, convert vaules to cluster index.
+ * Treat sectors before data region as all used, not to trim them.
+ */
+ ent_start = max_t(u64, range->start>>sbi->cluster_bits, FAT_START_ENT);
+ ent_end = ent_start + (range->len >> sbi->cluster_bits) - 1;
+ minlen = range->minlen >> sbi->cluster_bits;
+
+ if (ent_start >= sbi->max_cluster || range->len < sbi->cluster_size)
+ return -EINVAL;
+ if (ent_end >= sbi->max_cluster)
+ ent_end = sbi->max_cluster - 1;
+
+ reada_blocks = FAT_READA_SIZE >> sb->s_blocksize_bits;
+ reada_mask = reada_blocks - 1;
+
+ fatent_init(&fatent);
+ lock_fat(sbi);
+ fatent_set_entry(&fatent, ent_start);
+ while (fatent.entry <= ent_end) {
+ /* readahead of fat blocks */
+ if ((cur_block & reada_mask) == 0) {
+ unsigned long rest = sbi->fat_length - cur_block;
+ fat_ent_reada(sb, &fatent, min(reada_blocks, rest));
+ }
+ cur_block++;
+
+ err = fat_ent_read_block(sb, &fatent);
+ if (err)
+ goto error;
+ do {
+ if (ops->ent_get(&fatent) == FAT_ENT_FREE) {
+ free++;
+ } else if (free) {
+ if (free >= minlen) {
+ u32 clus = fatent.entry - free;
+
+ err = fat_trim_clusters(sb, clus, free);
+ if (err && err != -EOPNOTSUPP)
+ goto error;
+ if (!err)
+ trimmed += free;
+ err = 0;
+ }
+ free = 0;
+ }
+ } while (fat_ent_next(sbi, &fatent) && fatent.entry <= ent_end);
+
+ if (fatal_signal_pending(current)) {
+ err = -ERESTARTSYS;
+ goto error;
+ }
+
+ if (need_resched()) {
+ fatent_brelse(&fatent);
+ unlock_fat(sbi);
+ cond_resched();
+ lock_fat(sbi);
+ }
+ }
+ /* handle scenario when tail entries are all free */
+ if (free && free >= minlen) {
+ u32 clus = fatent.entry - free;
+
+ err = fat_trim_clusters(sb, clus, free);
+ if (err && err != -EOPNOTSUPP)
+ goto error;
+ if (!err)
+ trimmed += free;
+ err = 0;
+ }
+
+error:
+ fatent_brelse(&fatent);
+ unlock_fat(sbi);
+
+ range->len = trimmed << sbi->cluster_bits;
+
+ return err;
+}
diff --git a/fs/fat/file.c b/fs/fat/file.c
new file mode 100644
index 0000000..4f3d72f
--- /dev/null
+++ b/fs/fat/file.c
@@ -0,0 +1,555 @@
+/*
+ * linux/fs/fat/file.c
+ *
+ * Written 1992,1993 by Werner Almesberger
+ *
+ * regular file handling primitives for fat-based filesystems
+ */
+
+#include <linux/capability.h>
+#include <linux/module.h>
+#include <linux/compat.h>
+#include <linux/mount.h>
+#include <linux/blkdev.h>
+#include <linux/backing-dev.h>
+#include <linux/fsnotify.h>
+#include <linux/security.h>
+#include <linux/falloc.h>
+#include "fat.h"
+
+static long fat_fallocate(struct file *file, int mode,
+ loff_t offset, loff_t len);
+
+static int fat_ioctl_get_attributes(struct inode *inode, u32 __user *user_attr)
+{
+ u32 attr;
+
+ inode_lock(inode);
+ attr = fat_make_attrs(inode);
+ inode_unlock(inode);
+
+ return put_user(attr, user_attr);
+}
+
+static int fat_ioctl_set_attributes(struct file *file, u32 __user *user_attr)
+{
+ struct inode *inode = file_inode(file);
+ struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
+ int is_dir = S_ISDIR(inode->i_mode);
+ u32 attr, oldattr;
+ struct iattr ia;
+ int err;
+
+ err = get_user(attr, user_attr);
+ if (err)
+ goto out;
+
+ err = mnt_want_write_file(file);
+ if (err)
+ goto out;
+ inode_lock(inode);
+
+ /*
+ * ATTR_VOLUME and ATTR_DIR cannot be changed; this also
+ * prevents the user from turning us into a VFAT
+ * longname entry. Also, we obviously can't set
+ * any of the NTFS attributes in the high 24 bits.
+ */
+ attr &= 0xff & ~(ATTR_VOLUME | ATTR_DIR);
+ /* Merge in ATTR_VOLUME and ATTR_DIR */
+ attr |= (MSDOS_I(inode)->i_attrs & ATTR_VOLUME) |
+ (is_dir ? ATTR_DIR : 0);
+ oldattr = fat_make_attrs(inode);
+
+ /* Equivalent to a chmod() */
+ ia.ia_valid = ATTR_MODE | ATTR_CTIME;
+ ia.ia_ctime = current_time(inode);
+ if (is_dir)
+ ia.ia_mode = fat_make_mode(sbi, attr, S_IRWXUGO);
+ else {
+ ia.ia_mode = fat_make_mode(sbi, attr,
+ S_IRUGO | S_IWUGO | (inode->i_mode & S_IXUGO));
+ }
+
+ /* The root directory has no attributes */
+ if (inode->i_ino == MSDOS_ROOT_INO && attr != ATTR_DIR) {
+ err = -EINVAL;
+ goto out_unlock_inode;
+ }
+
+ if (sbi->options.sys_immutable &&
+ ((attr | oldattr) & ATTR_SYS) &&
+ !capable(CAP_LINUX_IMMUTABLE)) {
+ err = -EPERM;
+ goto out_unlock_inode;
+ }
+
+ /*
+ * The security check is questionable... We single
+ * out the RO attribute for checking by the security
+ * module, just because it maps to a file mode.
+ */
+ err = security_inode_setattr(file->f_path.dentry, &ia);
+ if (err)
+ goto out_unlock_inode;
+
+ /* This MUST be done before doing anything irreversible... */
+ err = fat_setattr(file->f_path.dentry, &ia);
+ if (err)
+ goto out_unlock_inode;
+
+ fsnotify_change(file->f_path.dentry, ia.ia_valid);
+ if (sbi->options.sys_immutable) {
+ if (attr & ATTR_SYS)
+ inode->i_flags |= S_IMMUTABLE;
+ else
+ inode->i_flags &= ~S_IMMUTABLE;
+ }
+
+ fat_save_attrs(inode, attr);
+ mark_inode_dirty(inode);
+out_unlock_inode:
+ inode_unlock(inode);
+ mnt_drop_write_file(file);
+out:
+ return err;
+}
+
+static int fat_ioctl_get_volume_id(struct inode *inode, u32 __user *user_attr)
+{
+ struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
+ return put_user(sbi->vol_id, user_attr);
+}
+
+static int fat_ioctl_fitrim(struct inode *inode, unsigned long arg)
+{
+ struct super_block *sb = inode->i_sb;
+ struct fstrim_range __user *user_range;
+ struct fstrim_range range;
+ struct request_queue *q = bdev_get_queue(sb->s_bdev);
+ int err;
+
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
+
+ if (!blk_queue_discard(q))
+ return -EOPNOTSUPP;
+
+ user_range = (struct fstrim_range __user *)arg;
+ if (copy_from_user(&range, user_range, sizeof(range)))
+ return -EFAULT;
+
+ range.minlen = max_t(unsigned int, range.minlen,
+ q->limits.discard_granularity);
+
+ err = fat_trim_fs(inode, &range);
+ if (err < 0)
+ return err;
+
+ if (copy_to_user(user_range, &range, sizeof(range)))
+ return -EFAULT;
+
+ return 0;
+}
+
+long fat_generic_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
+{
+ struct inode *inode = file_inode(filp);
+ u32 __user *user_attr = (u32 __user *)arg;
+
+ switch (cmd) {
+ case FAT_IOCTL_GET_ATTRIBUTES:
+ return fat_ioctl_get_attributes(inode, user_attr);
+ case FAT_IOCTL_SET_ATTRIBUTES:
+ return fat_ioctl_set_attributes(filp, user_attr);
+ case FAT_IOCTL_GET_VOLUME_ID:
+ return fat_ioctl_get_volume_id(inode, user_attr);
+ case FITRIM:
+ return fat_ioctl_fitrim(inode, arg);
+ default:
+ return -ENOTTY; /* Inappropriate ioctl for device */
+ }
+}
+
+#ifdef CONFIG_COMPAT
+static long fat_generic_compat_ioctl(struct file *filp, unsigned int cmd,
+ unsigned long arg)
+
+{
+ return fat_generic_ioctl(filp, cmd, (unsigned long)compat_ptr(arg));
+}
+#endif
+
+static int fat_file_release(struct inode *inode, struct file *filp)
+{
+ if ((filp->f_mode & FMODE_WRITE) &&
+ MSDOS_SB(inode->i_sb)->options.flush) {
+ fat_flush_inodes(inode->i_sb, inode, NULL);
+ congestion_wait(BLK_RW_ASYNC, HZ/10);
+ }
+ return 0;
+}
+
+int fat_file_fsync(struct file *filp, loff_t start, loff_t end, int datasync)
+{
+ struct inode *inode = filp->f_mapping->host;
+ int res, err;
+
+ res = generic_file_fsync(filp, start, end, datasync);
+ err = sync_mapping_buffers(MSDOS_SB(inode->i_sb)->fat_inode->i_mapping);
+
+ return res ? res : err;
+}
+
+
+const struct file_operations fat_file_operations = {
+ .llseek = generic_file_llseek,
+ .read_iter = generic_file_read_iter,
+ .write_iter = generic_file_write_iter,
+ .mmap = generic_file_mmap,
+ .release = fat_file_release,
+ .unlocked_ioctl = fat_generic_ioctl,
+#ifdef CONFIG_COMPAT
+ .compat_ioctl = fat_generic_compat_ioctl,
+#endif
+ .fsync = fat_file_fsync,
+ .splice_read = generic_file_splice_read,
+ .fallocate = fat_fallocate,
+};
+
+static int fat_cont_expand(struct inode *inode, loff_t size)
+{
+ struct address_space *mapping = inode->i_mapping;
+ loff_t start = inode->i_size, count = size - inode->i_size;
+ int err;
+
+ err = generic_cont_expand_simple(inode, size);
+ if (err)
+ goto out;
+
+ inode->i_ctime = inode->i_mtime = current_time(inode);
+ mark_inode_dirty(inode);
+ if (IS_SYNC(inode)) {
+ int err2;
+
+ /*
+ * Opencode syncing since we don't have a file open to use
+ * standard fsync path.
+ */
+ err = filemap_fdatawrite_range(mapping, start,
+ start + count - 1);
+ err2 = sync_mapping_buffers(mapping);
+ if (!err)
+ err = err2;
+ err2 = write_inode_now(inode, 1);
+ if (!err)
+ err = err2;
+ if (!err) {
+ err = filemap_fdatawait_range(mapping, start,
+ start + count - 1);
+ }
+ }
+out:
+ return err;
+}
+
+/*
+ * Preallocate space for a file. This implements fat's fallocate file
+ * operation, which gets called from sys_fallocate system call. User
+ * space requests len bytes at offset. If FALLOC_FL_KEEP_SIZE is set
+ * we just allocate clusters without zeroing them out. Otherwise we
+ * allocate and zero out clusters via an expanding truncate.
+ */
+static long fat_fallocate(struct file *file, int mode,
+ loff_t offset, loff_t len)
+{
+ int nr_cluster; /* Number of clusters to be allocated */
+ loff_t mm_bytes; /* Number of bytes to be allocated for file */
+ loff_t ondisksize; /* block aligned on-disk size in bytes*/
+ struct inode *inode = file->f_mapping->host;
+ struct super_block *sb = inode->i_sb;
+ struct msdos_sb_info *sbi = MSDOS_SB(sb);
+ int err = 0;
+
+ /* No support for hole punch or other fallocate flags. */
+ if (mode & ~FALLOC_FL_KEEP_SIZE)
+ return -EOPNOTSUPP;
+
+ /* No support for dir */
+ if (!S_ISREG(inode->i_mode))
+ return -EOPNOTSUPP;
+
+ inode_lock(inode);
+ if (mode & FALLOC_FL_KEEP_SIZE) {
+ ondisksize = inode->i_blocks << 9;
+ if ((offset + len) <= ondisksize)
+ goto error;
+
+ /* First compute the number of clusters to be allocated */
+ mm_bytes = offset + len - ondisksize;
+ nr_cluster = (mm_bytes + (sbi->cluster_size - 1)) >>
+ sbi->cluster_bits;
+
+ /* Start the allocation.We are not zeroing out the clusters */
+ while (nr_cluster-- > 0) {
+ err = fat_add_cluster(inode);
+ if (err)
+ goto error;
+ }
+ } else {
+ if ((offset + len) <= i_size_read(inode))
+ goto error;
+
+ /* This is just an expanding truncate */
+ err = fat_cont_expand(inode, (offset + len));
+ }
+
+error:
+ inode_unlock(inode);
+ return err;
+}
+
+/* Free all clusters after the skip'th cluster. */
+static int fat_free(struct inode *inode, int skip)
+{
+ struct super_block *sb = inode->i_sb;
+ int err, wait, free_start, i_start, i_logstart;
+
+ if (MSDOS_I(inode)->i_start == 0)
+ return 0;
+
+ fat_cache_inval_inode(inode);
+
+ wait = IS_DIRSYNC(inode);
+ i_start = free_start = MSDOS_I(inode)->i_start;
+ i_logstart = MSDOS_I(inode)->i_logstart;
+
+ /* First, we write the new file size. */
+ if (!skip) {
+ MSDOS_I(inode)->i_start = 0;
+ MSDOS_I(inode)->i_logstart = 0;
+ }
+ MSDOS_I(inode)->i_attrs |= ATTR_ARCH;
+ inode->i_ctime = inode->i_mtime = current_time(inode);
+ if (wait) {
+ err = fat_sync_inode(inode);
+ if (err) {
+ MSDOS_I(inode)->i_start = i_start;
+ MSDOS_I(inode)->i_logstart = i_logstart;
+ return err;
+ }
+ } else
+ mark_inode_dirty(inode);
+
+ /* Write a new EOF, and get the remaining cluster chain for freeing. */
+ if (skip) {
+ struct fat_entry fatent;
+ int ret, fclus, dclus;
+
+ ret = fat_get_cluster(inode, skip - 1, &fclus, &dclus);
+ if (ret < 0)
+ return ret;
+ else if (ret == FAT_ENT_EOF)
+ return 0;
+
+ fatent_init(&fatent);
+ ret = fat_ent_read(inode, &fatent, dclus);
+ if (ret == FAT_ENT_EOF) {
+ fatent_brelse(&fatent);
+ return 0;
+ } else if (ret == FAT_ENT_FREE) {
+ fat_fs_error(sb,
+ "%s: invalid cluster chain (i_pos %lld)",
+ __func__, MSDOS_I(inode)->i_pos);
+ ret = -EIO;
+ } else if (ret > 0) {
+ err = fat_ent_write(inode, &fatent, FAT_ENT_EOF, wait);
+ if (err)
+ ret = err;
+ }
+ fatent_brelse(&fatent);
+ if (ret < 0)
+ return ret;
+
+ free_start = ret;
+ }
+ inode->i_blocks = skip << (MSDOS_SB(sb)->cluster_bits - 9);
+
+ /* Freeing the remained cluster chain */
+ return fat_free_clusters(inode, free_start);
+}
+
+void fat_truncate_blocks(struct inode *inode, loff_t offset)
+{
+ struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
+ const unsigned int cluster_size = sbi->cluster_size;
+ int nr_clusters;
+
+ /*
+ * This protects against truncating a file bigger than it was then
+ * trying to write into the hole.
+ */
+ if (MSDOS_I(inode)->mmu_private > offset)
+ MSDOS_I(inode)->mmu_private = offset;
+
+ nr_clusters = (offset + (cluster_size - 1)) >> sbi->cluster_bits;
+
+ fat_free(inode, nr_clusters);
+ fat_flush_inodes(inode->i_sb, inode, NULL);
+}
+
+int fat_getattr(const struct path *path, struct kstat *stat,
+ u32 request_mask, unsigned int flags)
+{
+ struct inode *inode = d_inode(path->dentry);
+ generic_fillattr(inode, stat);
+ stat->blksize = MSDOS_SB(inode->i_sb)->cluster_size;
+
+ if (MSDOS_SB(inode->i_sb)->options.nfs == FAT_NFS_NOSTALE_RO) {
+ /* Use i_pos for ino. This is used as fileid of nfs. */
+ stat->ino = fat_i_pos_read(MSDOS_SB(inode->i_sb), inode);
+ }
+ return 0;
+}
+EXPORT_SYMBOL_GPL(fat_getattr);
+
+static int fat_sanitize_mode(const struct msdos_sb_info *sbi,
+ struct inode *inode, umode_t *mode_ptr)
+{
+ umode_t mask, perm;
+
+ /*
+ * Note, the basic check is already done by a caller of
+ * (attr->ia_mode & ~FAT_VALID_MODE)
+ */
+
+ if (S_ISREG(inode->i_mode))
+ mask = sbi->options.fs_fmask;
+ else
+ mask = sbi->options.fs_dmask;
+
+ perm = *mode_ptr & ~(S_IFMT | mask);
+
+ /*
+ * Of the r and x bits, all (subject to umask) must be present. Of the
+ * w bits, either all (subject to umask) or none must be present.
+ *
+ * If fat_mode_can_hold_ro(inode) is false, can't change w bits.
+ */
+ if ((perm & (S_IRUGO | S_IXUGO)) != (inode->i_mode & (S_IRUGO|S_IXUGO)))
+ return -EPERM;
+ if (fat_mode_can_hold_ro(inode)) {
+ if ((perm & S_IWUGO) && ((perm & S_IWUGO) != (S_IWUGO & ~mask)))
+ return -EPERM;
+ } else {
+ if ((perm & S_IWUGO) != (S_IWUGO & ~mask))
+ return -EPERM;
+ }
+
+ *mode_ptr &= S_IFMT | perm;
+
+ return 0;
+}
+
+static int fat_allow_set_time(struct msdos_sb_info *sbi, struct inode *inode)
+{
+ umode_t allow_utime = sbi->options.allow_utime;
+
+ if (!uid_eq(current_fsuid(), inode->i_uid)) {
+ if (in_group_p(inode->i_gid))
+ allow_utime >>= 3;
+ if (allow_utime & MAY_WRITE)
+ return 1;
+ }
+
+ /* use a default check */
+ return 0;
+}
+
+#define TIMES_SET_FLAGS (ATTR_MTIME_SET | ATTR_ATIME_SET | ATTR_TIMES_SET)
+/* valid file mode bits */
+#define FAT_VALID_MODE (S_IFREG | S_IFDIR | S_IRWXUGO)
+
+int fat_setattr(struct dentry *dentry, struct iattr *attr)
+{
+ struct msdos_sb_info *sbi = MSDOS_SB(dentry->d_sb);
+ struct inode *inode = d_inode(dentry);
+ unsigned int ia_valid;
+ int error;
+
+ /* Check for setting the inode time. */
+ ia_valid = attr->ia_valid;
+ if (ia_valid & TIMES_SET_FLAGS) {
+ if (fat_allow_set_time(sbi, inode))
+ attr->ia_valid &= ~TIMES_SET_FLAGS;
+ }
+
+ error = setattr_prepare(dentry, attr);
+ attr->ia_valid = ia_valid;
+ if (error) {
+ if (sbi->options.quiet)
+ error = 0;
+ goto out;
+ }
+
+ /*
+ * Expand the file. Since inode_setattr() updates ->i_size
+ * before calling the ->truncate(), but FAT needs to fill the
+ * hole before it. XXX: this is no longer true with new truncate
+ * sequence.
+ */
+ if (attr->ia_valid & ATTR_SIZE) {
+ inode_dio_wait(inode);
+
+ if (attr->ia_size > inode->i_size) {
+ error = fat_cont_expand(inode, attr->ia_size);
+ if (error || attr->ia_valid == ATTR_SIZE)
+ goto out;
+ attr->ia_valid &= ~ATTR_SIZE;
+ }
+ }
+
+ if (((attr->ia_valid & ATTR_UID) &&
+ (!uid_eq(attr->ia_uid, sbi->options.fs_uid))) ||
+ ((attr->ia_valid & ATTR_GID) &&
+ (!gid_eq(attr->ia_gid, sbi->options.fs_gid))) ||
+ ((attr->ia_valid & ATTR_MODE) &&
+ (attr->ia_mode & ~FAT_VALID_MODE)))
+ error = -EPERM;
+
+ if (error) {
+ if (sbi->options.quiet)
+ error = 0;
+ goto out;
+ }
+
+ /*
+ * We don't return -EPERM here. Yes, strange, but this is too
+ * old behavior.
+ */
+ if (attr->ia_valid & ATTR_MODE) {
+ if (fat_sanitize_mode(sbi, inode, &attr->ia_mode) < 0)
+ attr->ia_valid &= ~ATTR_MODE;
+ }
+
+ if (attr->ia_valid & ATTR_SIZE) {
+ error = fat_block_truncate_page(inode, attr->ia_size);
+ if (error)
+ goto out;
+ down_write(&MSDOS_I(inode)->truncate_lock);
+ truncate_setsize(inode, attr->ia_size);
+ fat_truncate_blocks(inode, attr->ia_size);
+ up_write(&MSDOS_I(inode)->truncate_lock);
+ }
+
+ setattr_copy(inode, attr);
+ mark_inode_dirty(inode);
+out:
+ return error;
+}
+EXPORT_SYMBOL_GPL(fat_setattr);
+
+const struct inode_operations fat_file_inode_operations = {
+ .setattr = fat_setattr,
+ .getattr = fat_getattr,
+};
diff --git a/fs/fat/inode.c b/fs/fat/inode.c
new file mode 100644
index 0000000..d6b81e3
--- /dev/null
+++ b/fs/fat/inode.c
@@ -0,0 +1,1965 @@
+/*
+ * linux/fs/fat/inode.c
+ *
+ * Written 1992,1993 by Werner Almesberger
+ * VFAT extensions by Gordon Chaffee, merged with msdos fs by Henrik Storner
+ * Rewritten for the constant inumbers support by Al Viro
+ *
+ * Fixes:
+ *
+ * Max Cohan: Fixed invalid FSINFO offset when info_sector is 0
+ */
+
+#include <linux/module.h>
+#include <linux/pagemap.h>
+#include <linux/mpage.h>
+#include <linux/vfs.h>
+#include <linux/seq_file.h>
+#include <linux/parser.h>
+#include <linux/uio.h>
+#include <linux/blkdev.h>
+#include <linux/backing-dev.h>
+#include <asm/unaligned.h>
+#include <linux/iversion.h>
+#include "fat.h"
+
+#ifndef CONFIG_FAT_DEFAULT_IOCHARSET
+/* if user don't select VFAT, this is undefined. */
+#define CONFIG_FAT_DEFAULT_IOCHARSET ""
+#endif
+
+#define KB_IN_SECTORS 2
+
+/*
+ * A deserialized copy of the on-disk structure laid out in struct
+ * fat_boot_sector.
+ */
+struct fat_bios_param_block {
+ u16 fat_sector_size;
+ u8 fat_sec_per_clus;
+ u16 fat_reserved;
+ u8 fat_fats;
+ u16 fat_dir_entries;
+ u16 fat_sectors;
+ u16 fat_fat_length;
+ u32 fat_total_sect;
+
+ u8 fat16_state;
+ u32 fat16_vol_id;
+
+ u32 fat32_length;
+ u32 fat32_root_cluster;
+ u16 fat32_info_sector;
+ u8 fat32_state;
+ u32 fat32_vol_id;
+};
+
+static int fat_default_codepage = CONFIG_FAT_DEFAULT_CODEPAGE;
+static char fat_default_iocharset[] = CONFIG_FAT_DEFAULT_IOCHARSET;
+
+static struct fat_floppy_defaults {
+ unsigned nr_sectors;
+ unsigned sec_per_clus;
+ unsigned dir_entries;
+ unsigned media;
+ unsigned fat_length;
+} floppy_defaults[] = {
+{
+ .nr_sectors = 160 * KB_IN_SECTORS,
+ .sec_per_clus = 1,
+ .dir_entries = 64,
+ .media = 0xFE,
+ .fat_length = 1,
+},
+{
+ .nr_sectors = 180 * KB_IN_SECTORS,
+ .sec_per_clus = 1,
+ .dir_entries = 64,
+ .media = 0xFC,
+ .fat_length = 2,
+},
+{
+ .nr_sectors = 320 * KB_IN_SECTORS,
+ .sec_per_clus = 2,
+ .dir_entries = 112,
+ .media = 0xFF,
+ .fat_length = 1,
+},
+{
+ .nr_sectors = 360 * KB_IN_SECTORS,
+ .sec_per_clus = 2,
+ .dir_entries = 112,
+ .media = 0xFD,
+ .fat_length = 2,
+},
+};
+
+int fat_add_cluster(struct inode *inode)
+{
+ int err, cluster;
+
+ err = fat_alloc_clusters(inode, &cluster, 1);
+ if (err)
+ return err;
+ /* FIXME: this cluster should be added after data of this
+ * cluster is writed */
+ err = fat_chain_add(inode, cluster, 1);
+ if (err)
+ fat_free_clusters(inode, cluster);
+ return err;
+}
+
+static inline int __fat_get_block(struct inode *inode, sector_t iblock,
+ unsigned long *max_blocks,
+ struct buffer_head *bh_result, int create)
+{
+ struct super_block *sb = inode->i_sb;
+ struct msdos_sb_info *sbi = MSDOS_SB(sb);
+ unsigned long mapped_blocks;
+ sector_t phys, last_block;
+ int err, offset;
+
+ err = fat_bmap(inode, iblock, &phys, &mapped_blocks, create, false);
+ if (err)
+ return err;
+ if (phys) {
+ map_bh(bh_result, sb, phys);
+ *max_blocks = min(mapped_blocks, *max_blocks);
+ return 0;
+ }
+ if (!create)
+ return 0;
+
+ if (iblock != MSDOS_I(inode)->mmu_private >> sb->s_blocksize_bits) {
+ fat_fs_error(sb, "corrupted file size (i_pos %lld, %lld)",
+ MSDOS_I(inode)->i_pos, MSDOS_I(inode)->mmu_private);
+ return -EIO;
+ }
+
+ last_block = inode->i_blocks >> (sb->s_blocksize_bits - 9);
+ offset = (unsigned long)iblock & (sbi->sec_per_clus - 1);
+ /*
+ * allocate a cluster according to the following.
+ * 1) no more available blocks
+ * 2) not part of fallocate region
+ */
+ if (!offset && !(iblock < last_block)) {
+ /* TODO: multiple cluster allocation would be desirable. */
+ err = fat_add_cluster(inode);
+ if (err)
+ return err;
+ }
+ /* available blocks on this cluster */
+ mapped_blocks = sbi->sec_per_clus - offset;
+
+ *max_blocks = min(mapped_blocks, *max_blocks);
+ MSDOS_I(inode)->mmu_private += *max_blocks << sb->s_blocksize_bits;
+
+ err = fat_bmap(inode, iblock, &phys, &mapped_blocks, create, false);
+ if (err)
+ return err;
+ if (!phys) {
+ fat_fs_error(sb,
+ "invalid FAT chain (i_pos %lld, last_block %llu)",
+ MSDOS_I(inode)->i_pos,
+ (unsigned long long)last_block);
+ return -EIO;
+ }
+
+ BUG_ON(*max_blocks != mapped_blocks);
+ set_buffer_new(bh_result);
+ map_bh(bh_result, sb, phys);
+
+ return 0;
+}
+
+static int fat_get_block(struct inode *inode, sector_t iblock,
+ struct buffer_head *bh_result, int create)
+{
+ struct super_block *sb = inode->i_sb;
+ unsigned long max_blocks = bh_result->b_size >> inode->i_blkbits;
+ int err;
+
+ err = __fat_get_block(inode, iblock, &max_blocks, bh_result, create);
+ if (err)
+ return err;
+ bh_result->b_size = max_blocks << sb->s_blocksize_bits;
+ return 0;
+}
+
+static int fat_writepage(struct page *page, struct writeback_control *wbc)
+{
+ return block_write_full_page(page, fat_get_block, wbc);
+}
+
+static int fat_writepages(struct address_space *mapping,
+ struct writeback_control *wbc)
+{
+ return mpage_writepages(mapping, wbc, fat_get_block);
+}
+
+static int fat_readpage(struct file *file, struct page *page)
+{
+ return mpage_readpage(page, fat_get_block);
+}
+
+static int fat_readpages(struct file *file, struct address_space *mapping,
+ struct list_head *pages, unsigned nr_pages)
+{
+ return mpage_readpages(mapping, pages, nr_pages, fat_get_block);
+}
+
+static void fat_write_failed(struct address_space *mapping, loff_t to)
+{
+ struct inode *inode = mapping->host;
+
+ if (to > inode->i_size) {
+ truncate_pagecache(inode, inode->i_size);
+ fat_truncate_blocks(inode, inode->i_size);
+ }
+}
+
+static int fat_write_begin(struct file *file, struct address_space *mapping,
+ loff_t pos, unsigned len, unsigned flags,
+ struct page **pagep, void **fsdata)
+{
+ int err;
+
+ *pagep = NULL;
+ err = cont_write_begin(file, mapping, pos, len, flags,
+ pagep, fsdata, fat_get_block,
+ &MSDOS_I(mapping->host)->mmu_private);
+ if (err < 0)
+ fat_write_failed(mapping, pos + len);
+ return err;
+}
+
+static int fat_write_end(struct file *file, struct address_space *mapping,
+ loff_t pos, unsigned len, unsigned copied,
+ struct page *pagep, void *fsdata)
+{
+ struct inode *inode = mapping->host;
+ int err;
+ err = generic_write_end(file, mapping, pos, len, copied, pagep, fsdata);
+ if (err < len)
+ fat_write_failed(mapping, pos + len);
+ if (!(err < 0) && !(MSDOS_I(inode)->i_attrs & ATTR_ARCH)) {
+ inode->i_mtime = inode->i_ctime = current_time(inode);
+ MSDOS_I(inode)->i_attrs |= ATTR_ARCH;
+ mark_inode_dirty(inode);
+ }
+ return err;
+}
+
+static ssize_t fat_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
+{
+ struct file *file = iocb->ki_filp;
+ struct address_space *mapping = file->f_mapping;
+ struct inode *inode = mapping->host;
+ size_t count = iov_iter_count(iter);
+ loff_t offset = iocb->ki_pos;
+ ssize_t ret;
+
+ if (iov_iter_rw(iter) == WRITE) {
+ /*
+ * FIXME: blockdev_direct_IO() doesn't use ->write_begin(),
+ * so we need to update the ->mmu_private to block boundary.
+ *
+ * But we must fill the remaining area or hole by nul for
+ * updating ->mmu_private.
+ *
+ * Return 0, and fallback to normal buffered write.
+ */
+ loff_t size = offset + count;
+ if (MSDOS_I(inode)->mmu_private < size)
+ return 0;
+ }
+
+ /*
+ * FAT need to use the DIO_LOCKING for avoiding the race
+ * condition of fat_get_block() and ->truncate().
+ */
+ ret = blockdev_direct_IO(iocb, inode, iter, fat_get_block);
+ if (ret < 0 && iov_iter_rw(iter) == WRITE)
+ fat_write_failed(mapping, offset + count);
+
+ return ret;
+}
+
+static int fat_get_block_bmap(struct inode *inode, sector_t iblock,
+ struct buffer_head *bh_result, int create)
+{
+ struct super_block *sb = inode->i_sb;
+ unsigned long max_blocks = bh_result->b_size >> inode->i_blkbits;
+ int err;
+ sector_t bmap;
+ unsigned long mapped_blocks;
+
+ BUG_ON(create != 0);
+
+ err = fat_bmap(inode, iblock, &bmap, &mapped_blocks, create, true);
+ if (err)
+ return err;
+
+ if (bmap) {
+ map_bh(bh_result, sb, bmap);
+ max_blocks = min(mapped_blocks, max_blocks);
+ }
+
+ bh_result->b_size = max_blocks << sb->s_blocksize_bits;
+
+ return 0;
+}
+
+static sector_t _fat_bmap(struct address_space *mapping, sector_t block)
+{
+ sector_t blocknr;
+
+ /* fat_get_cluster() assumes the requested blocknr isn't truncated. */
+ down_read(&MSDOS_I(mapping->host)->truncate_lock);
+ blocknr = generic_block_bmap(mapping, block, fat_get_block_bmap);
+ up_read(&MSDOS_I(mapping->host)->truncate_lock);
+
+ return blocknr;
+}
+
+/*
+ * fat_block_truncate_page() zeroes out a mapping from file offset `from'
+ * up to the end of the block which corresponds to `from'.
+ * This is required during truncate to physically zeroout the tail end
+ * of that block so it doesn't yield old data if the file is later grown.
+ * Also, avoid causing failure from fsx for cases of "data past EOF"
+ */
+int fat_block_truncate_page(struct inode *inode, loff_t from)
+{
+ return block_truncate_page(inode->i_mapping, from, fat_get_block);
+}
+
+static const struct address_space_operations fat_aops = {
+ .readpage = fat_readpage,
+ .readpages = fat_readpages,
+ .writepage = fat_writepage,
+ .writepages = fat_writepages,
+ .write_begin = fat_write_begin,
+ .write_end = fat_write_end,
+ .direct_IO = fat_direct_IO,
+ .bmap = _fat_bmap
+};
+
+/*
+ * New FAT inode stuff. We do the following:
+ * a) i_ino is constant and has nothing with on-disk location.
+ * b) FAT manages its own cache of directory entries.
+ * c) *This* cache is indexed by on-disk location.
+ * d) inode has an associated directory entry, all right, but
+ * it may be unhashed.
+ * e) currently entries are stored within struct inode. That should
+ * change.
+ * f) we deal with races in the following way:
+ * 1. readdir() and lookup() do FAT-dir-cache lookup.
+ * 2. rename() unhashes the F-d-c entry and rehashes it in
+ * a new place.
+ * 3. unlink() and rmdir() unhash F-d-c entry.
+ * 4. fat_write_inode() checks whether the thing is unhashed.
+ * If it is we silently return. If it isn't we do bread(),
+ * check if the location is still valid and retry if it
+ * isn't. Otherwise we do changes.
+ * 5. Spinlock is used to protect hash/unhash/location check/lookup
+ * 6. fat_evict_inode() unhashes the F-d-c entry.
+ * 7. lookup() and readdir() do igrab() if they find a F-d-c entry
+ * and consider negative result as cache miss.
+ */
+
+static void fat_hash_init(struct super_block *sb)
+{
+ struct msdos_sb_info *sbi = MSDOS_SB(sb);
+ int i;
+
+ spin_lock_init(&sbi->inode_hash_lock);
+ for (i = 0; i < FAT_HASH_SIZE; i++)
+ INIT_HLIST_HEAD(&sbi->inode_hashtable[i]);
+}
+
+static inline unsigned long fat_hash(loff_t i_pos)
+{
+ return hash_32(i_pos, FAT_HASH_BITS);
+}
+
+static void dir_hash_init(struct super_block *sb)
+{
+ struct msdos_sb_info *sbi = MSDOS_SB(sb);
+ int i;
+
+ spin_lock_init(&sbi->dir_hash_lock);
+ for (i = 0; i < FAT_HASH_SIZE; i++)
+ INIT_HLIST_HEAD(&sbi->dir_hashtable[i]);
+}
+
+void fat_attach(struct inode *inode, loff_t i_pos)
+{
+ struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
+
+ if (inode->i_ino != MSDOS_ROOT_INO) {
+ struct hlist_head *head = sbi->inode_hashtable
+ + fat_hash(i_pos);
+
+ spin_lock(&sbi->inode_hash_lock);
+ MSDOS_I(inode)->i_pos = i_pos;
+ hlist_add_head(&MSDOS_I(inode)->i_fat_hash, head);
+ spin_unlock(&sbi->inode_hash_lock);
+ }
+
+ /* If NFS support is enabled, cache the mapping of start cluster
+ * to directory inode. This is used during reconnection of
+ * dentries to the filesystem root.
+ */
+ if (S_ISDIR(inode->i_mode) && sbi->options.nfs) {
+ struct hlist_head *d_head = sbi->dir_hashtable;
+ d_head += fat_dir_hash(MSDOS_I(inode)->i_logstart);
+
+ spin_lock(&sbi->dir_hash_lock);
+ hlist_add_head(&MSDOS_I(inode)->i_dir_hash, d_head);
+ spin_unlock(&sbi->dir_hash_lock);
+ }
+}
+EXPORT_SYMBOL_GPL(fat_attach);
+
+void fat_detach(struct inode *inode)
+{
+ struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
+ spin_lock(&sbi->inode_hash_lock);
+ MSDOS_I(inode)->i_pos = 0;
+ hlist_del_init(&MSDOS_I(inode)->i_fat_hash);
+ spin_unlock(&sbi->inode_hash_lock);
+
+ if (S_ISDIR(inode->i_mode) && sbi->options.nfs) {
+ spin_lock(&sbi->dir_hash_lock);
+ hlist_del_init(&MSDOS_I(inode)->i_dir_hash);
+ spin_unlock(&sbi->dir_hash_lock);
+ }
+}
+EXPORT_SYMBOL_GPL(fat_detach);
+
+struct inode *fat_iget(struct super_block *sb, loff_t i_pos)
+{
+ struct msdos_sb_info *sbi = MSDOS_SB(sb);
+ struct hlist_head *head = sbi->inode_hashtable + fat_hash(i_pos);
+ struct msdos_inode_info *i;
+ struct inode *inode = NULL;
+
+ spin_lock(&sbi->inode_hash_lock);
+ hlist_for_each_entry(i, head, i_fat_hash) {
+ BUG_ON(i->vfs_inode.i_sb != sb);
+ if (i->i_pos != i_pos)
+ continue;
+ inode = igrab(&i->vfs_inode);
+ if (inode)
+ break;
+ }
+ spin_unlock(&sbi->inode_hash_lock);
+ return inode;
+}
+
+static int is_exec(unsigned char *extension)
+{
+ unsigned char exe_extensions[] = "EXECOMBAT", *walk;
+
+ for (walk = exe_extensions; *walk; walk += 3)
+ if (!strncmp(extension, walk, 3))
+ return 1;
+ return 0;
+}
+
+static int fat_calc_dir_size(struct inode *inode)
+{
+ struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
+ int ret, fclus, dclus;
+
+ inode->i_size = 0;
+ if (MSDOS_I(inode)->i_start == 0)
+ return 0;
+
+ ret = fat_get_cluster(inode, FAT_ENT_EOF, &fclus, &dclus);
+ if (ret < 0)
+ return ret;
+ inode->i_size = (fclus + 1) << sbi->cluster_bits;
+
+ return 0;
+}
+
+static int fat_validate_dir(struct inode *dir)
+{
+ struct super_block *sb = dir->i_sb;
+
+ if (dir->i_nlink < 2) {
+ /* Directory should have "."/".." entries at least. */
+ fat_fs_error(sb, "corrupted directory (invalid entries)");
+ return -EIO;
+ }
+ if (MSDOS_I(dir)->i_start == 0 ||
+ MSDOS_I(dir)->i_start == MSDOS_SB(sb)->root_cluster) {
+ /* Directory should point valid cluster. */
+ fat_fs_error(sb, "corrupted directory (invalid i_start)");
+ return -EIO;
+ }
+ return 0;
+}
+
+/* doesn't deal with root inode */
+int fat_fill_inode(struct inode *inode, struct msdos_dir_entry *de)
+{
+ struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
+ int error;
+
+ MSDOS_I(inode)->i_pos = 0;
+ inode->i_uid = sbi->options.fs_uid;
+ inode->i_gid = sbi->options.fs_gid;
+ inode_inc_iversion(inode);
+ inode->i_generation = get_seconds();
+
+ if ((de->attr & ATTR_DIR) && !IS_FREE(de->name)) {
+ inode->i_generation &= ~1;
+ inode->i_mode = fat_make_mode(sbi, de->attr, S_IRWXUGO);
+ inode->i_op = sbi->dir_ops;
+ inode->i_fop = &fat_dir_operations;
+
+ MSDOS_I(inode)->i_start = fat_get_start(sbi, de);
+ MSDOS_I(inode)->i_logstart = MSDOS_I(inode)->i_start;
+ error = fat_calc_dir_size(inode);
+ if (error < 0)
+ return error;
+ MSDOS_I(inode)->mmu_private = inode->i_size;
+
+ set_nlink(inode, fat_subdirs(inode));
+
+ error = fat_validate_dir(inode);
+ if (error < 0)
+ return error;
+ } else { /* not a directory */
+ inode->i_generation |= 1;
+ inode->i_mode = fat_make_mode(sbi, de->attr,
+ ((sbi->options.showexec && !is_exec(de->name + 8))
+ ? S_IRUGO|S_IWUGO : S_IRWXUGO));
+ MSDOS_I(inode)->i_start = fat_get_start(sbi, de);
+
+ MSDOS_I(inode)->i_logstart = MSDOS_I(inode)->i_start;
+ inode->i_size = le32_to_cpu(de->size);
+ inode->i_op = &fat_file_inode_operations;
+ inode->i_fop = &fat_file_operations;
+ inode->i_mapping->a_ops = &fat_aops;
+ MSDOS_I(inode)->mmu_private = inode->i_size;
+ }
+ if (de->attr & ATTR_SYS) {
+ if (sbi->options.sys_immutable)
+ inode->i_flags |= S_IMMUTABLE;
+ }
+ fat_save_attrs(inode, de->attr);
+
+ inode->i_blocks = ((inode->i_size + (sbi->cluster_size - 1))
+ & ~((loff_t)sbi->cluster_size - 1)) >> 9;
+
+ fat_time_fat2unix(sbi, &inode->i_mtime, de->time, de->date, 0);
+ if (sbi->options.isvfat) {
+ fat_time_fat2unix(sbi, &inode->i_ctime, de->ctime,
+ de->cdate, de->ctime_cs);
+ fat_time_fat2unix(sbi, &inode->i_atime, 0, de->adate, 0);
+ } else
+ inode->i_ctime = inode->i_atime = inode->i_mtime;
+
+ return 0;
+}
+
+static inline void fat_lock_build_inode(struct msdos_sb_info *sbi)
+{
+ if (sbi->options.nfs == FAT_NFS_NOSTALE_RO)
+ mutex_lock(&sbi->nfs_build_inode_lock);
+}
+
+static inline void fat_unlock_build_inode(struct msdos_sb_info *sbi)
+{
+ if (sbi->options.nfs == FAT_NFS_NOSTALE_RO)
+ mutex_unlock(&sbi->nfs_build_inode_lock);
+}
+
+struct inode *fat_build_inode(struct super_block *sb,
+ struct msdos_dir_entry *de, loff_t i_pos)
+{
+ struct inode *inode;
+ int err;
+
+ fat_lock_build_inode(MSDOS_SB(sb));
+ inode = fat_iget(sb, i_pos);
+ if (inode)
+ goto out;
+ inode = new_inode(sb);
+ if (!inode) {
+ inode = ERR_PTR(-ENOMEM);
+ goto out;
+ }
+ inode->i_ino = iunique(sb, MSDOS_ROOT_INO);
+ inode_set_iversion(inode, 1);
+ err = fat_fill_inode(inode, de);
+ if (err) {
+ iput(inode);
+ inode = ERR_PTR(err);
+ goto out;
+ }
+ fat_attach(inode, i_pos);
+ insert_inode_hash(inode);
+out:
+ fat_unlock_build_inode(MSDOS_SB(sb));
+ return inode;
+}
+
+EXPORT_SYMBOL_GPL(fat_build_inode);
+
+static int __fat_write_inode(struct inode *inode, int wait);
+
+static void fat_free_eofblocks(struct inode *inode)
+{
+ /* Release unwritten fallocated blocks on inode eviction. */
+ if ((inode->i_blocks << 9) >
+ round_up(MSDOS_I(inode)->mmu_private,
+ MSDOS_SB(inode->i_sb)->cluster_size)) {
+ int err;
+
+ fat_truncate_blocks(inode, MSDOS_I(inode)->mmu_private);
+ /* Fallocate results in updating the i_start/iogstart
+ * for the zero byte file. So, make it return to
+ * original state during evict and commit it to avoid
+ * any corruption on the next access to the cluster
+ * chain for the file.
+ */
+ err = __fat_write_inode(inode, inode_needs_sync(inode));
+ if (err) {
+ fat_msg(inode->i_sb, KERN_WARNING, "Failed to "
+ "update on disk inode for unused "
+ "fallocated blocks, inode could be "
+ "corrupted. Please run fsck");
+ }
+
+ }
+}
+
+static void fat_evict_inode(struct inode *inode)
+{
+ truncate_inode_pages_final(&inode->i_data);
+ if (!inode->i_nlink) {
+ inode->i_size = 0;
+ fat_truncate_blocks(inode, 0);
+ } else
+ fat_free_eofblocks(inode);
+
+ invalidate_inode_buffers(inode);
+ clear_inode(inode);
+ fat_cache_inval_inode(inode);
+ fat_detach(inode);
+}
+
+static void fat_set_state(struct super_block *sb,
+ unsigned int set, unsigned int force)
+{
+ struct buffer_head *bh;
+ struct fat_boot_sector *b;
+ struct msdos_sb_info *sbi = MSDOS_SB(sb);
+
+ /* do not change any thing if mounted read only */
+ if (sb_rdonly(sb) && !force)
+ return;
+
+ /* do not change state if fs was dirty */
+ if (sbi->dirty) {
+ /* warn only on set (mount). */
+ if (set)
+ fat_msg(sb, KERN_WARNING, "Volume was not properly "
+ "unmounted. Some data may be corrupt. "
+ "Please run fsck.");
+ return;
+ }
+
+ bh = sb_bread(sb, 0);
+ if (bh == NULL) {
+ fat_msg(sb, KERN_ERR, "unable to read boot sector "
+ "to mark fs as dirty");
+ return;
+ }
+
+ b = (struct fat_boot_sector *) bh->b_data;
+
+ if (sbi->fat_bits == 32) {
+ if (set)
+ b->fat32.state |= FAT_STATE_DIRTY;
+ else
+ b->fat32.state &= ~FAT_STATE_DIRTY;
+ } else /* fat 16 and 12 */ {
+ if (set)
+ b->fat16.state |= FAT_STATE_DIRTY;
+ else
+ b->fat16.state &= ~FAT_STATE_DIRTY;
+ }
+
+ mark_buffer_dirty(bh);
+ sync_dirty_buffer(bh);
+ brelse(bh);
+}
+
+static void fat_reset_iocharset(struct fat_mount_options *opts)
+{
+ if (opts->iocharset != fat_default_iocharset) {
+ /* Note: opts->iocharset can be NULL here */
+ kfree(opts->iocharset);
+ opts->iocharset = fat_default_iocharset;
+ }
+}
+
+static void delayed_free(struct rcu_head *p)
+{
+ struct msdos_sb_info *sbi = container_of(p, struct msdos_sb_info, rcu);
+ unload_nls(sbi->nls_disk);
+ unload_nls(sbi->nls_io);
+ fat_reset_iocharset(&sbi->options);
+ kfree(sbi);
+}
+
+static void fat_put_super(struct super_block *sb)
+{
+ struct msdos_sb_info *sbi = MSDOS_SB(sb);
+
+ fat_set_state(sb, 0, 0);
+
+ iput(sbi->fsinfo_inode);
+ iput(sbi->fat_inode);
+
+ call_rcu(&sbi->rcu, delayed_free);
+}
+
+static struct kmem_cache *fat_inode_cachep;
+
+static struct inode *fat_alloc_inode(struct super_block *sb)
+{
+ struct msdos_inode_info *ei;
+ ei = kmem_cache_alloc(fat_inode_cachep, GFP_NOFS);
+ if (!ei)
+ return NULL;
+
+ init_rwsem(&ei->truncate_lock);
+ return &ei->vfs_inode;
+}
+
+static void fat_i_callback(struct rcu_head *head)
+{
+ struct inode *inode = container_of(head, struct inode, i_rcu);
+ kmem_cache_free(fat_inode_cachep, MSDOS_I(inode));
+}
+
+static void fat_destroy_inode(struct inode *inode)
+{
+ call_rcu(&inode->i_rcu, fat_i_callback);
+}
+
+static void init_once(void *foo)
+{
+ struct msdos_inode_info *ei = (struct msdos_inode_info *)foo;
+
+ spin_lock_init(&ei->cache_lru_lock);
+ ei->nr_caches = 0;
+ ei->cache_valid_id = FAT_CACHE_VALID + 1;
+ INIT_LIST_HEAD(&ei->cache_lru);
+ INIT_HLIST_NODE(&ei->i_fat_hash);
+ INIT_HLIST_NODE(&ei->i_dir_hash);
+ inode_init_once(&ei->vfs_inode);
+}
+
+static int __init fat_init_inodecache(void)
+{
+ fat_inode_cachep = kmem_cache_create("fat_inode_cache",
+ sizeof(struct msdos_inode_info),
+ 0, (SLAB_RECLAIM_ACCOUNT|
+ SLAB_MEM_SPREAD|SLAB_ACCOUNT),
+ init_once);
+ if (fat_inode_cachep == NULL)
+ return -ENOMEM;
+ return 0;
+}
+
+static void __exit fat_destroy_inodecache(void)
+{
+ /*
+ * Make sure all delayed rcu free inodes are flushed before we
+ * destroy cache.
+ */
+ rcu_barrier();
+ kmem_cache_destroy(fat_inode_cachep);
+}
+
+static int fat_remount(struct super_block *sb, int *flags, char *data)
+{
+ bool new_rdonly;
+ struct msdos_sb_info *sbi = MSDOS_SB(sb);
+ *flags |= SB_NODIRATIME | (sbi->options.isvfat ? 0 : SB_NOATIME);
+
+ sync_filesystem(sb);
+
+ /* make sure we update state on remount. */
+ new_rdonly = *flags & SB_RDONLY;
+ if (new_rdonly != sb_rdonly(sb)) {
+ if (new_rdonly)
+ fat_set_state(sb, 0, 0);
+ else
+ fat_set_state(sb, 1, 1);
+ }
+ return 0;
+}
+
+static int fat_statfs(struct dentry *dentry, struct kstatfs *buf)
+{
+ struct super_block *sb = dentry->d_sb;
+ struct msdos_sb_info *sbi = MSDOS_SB(sb);
+ u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
+
+ /* If the count of free cluster is still unknown, counts it here. */
+ if (sbi->free_clusters == -1 || !sbi->free_clus_valid) {
+ int err = fat_count_free_clusters(dentry->d_sb);
+ if (err)
+ return err;
+ }
+
+ buf->f_type = dentry->d_sb->s_magic;
+ buf->f_bsize = sbi->cluster_size;
+ buf->f_blocks = sbi->max_cluster - FAT_START_ENT;
+ buf->f_bfree = sbi->free_clusters;
+ buf->f_bavail = sbi->free_clusters;
+ buf->f_fsid.val[0] = (u32)id;
+ buf->f_fsid.val[1] = (u32)(id >> 32);
+ buf->f_namelen =
+ (sbi->options.isvfat ? FAT_LFN_LEN : 12) * NLS_MAX_CHARSET_SIZE;
+
+ return 0;
+}
+
+static int __fat_write_inode(struct inode *inode, int wait)
+{
+ struct super_block *sb = inode->i_sb;
+ struct msdos_sb_info *sbi = MSDOS_SB(sb);
+ struct buffer_head *bh;
+ struct msdos_dir_entry *raw_entry;
+ loff_t i_pos;
+ sector_t blocknr;
+ int err, offset;
+
+ if (inode->i_ino == MSDOS_ROOT_INO)
+ return 0;
+
+retry:
+ i_pos = fat_i_pos_read(sbi, inode);
+ if (!i_pos)
+ return 0;
+
+ fat_get_blknr_offset(sbi, i_pos, &blocknr, &offset);
+ bh = sb_bread(sb, blocknr);
+ if (!bh) {
+ fat_msg(sb, KERN_ERR, "unable to read inode block "
+ "for updating (i_pos %lld)", i_pos);
+ return -EIO;
+ }
+ spin_lock(&sbi->inode_hash_lock);
+ if (i_pos != MSDOS_I(inode)->i_pos) {
+ spin_unlock(&sbi->inode_hash_lock);
+ brelse(bh);
+ goto retry;
+ }
+
+ raw_entry = &((struct msdos_dir_entry *) (bh->b_data))[offset];
+ if (S_ISDIR(inode->i_mode))
+ raw_entry->size = 0;
+ else
+ raw_entry->size = cpu_to_le32(inode->i_size);
+ raw_entry->attr = fat_make_attrs(inode);
+ fat_set_start(raw_entry, MSDOS_I(inode)->i_logstart);
+ fat_time_unix2fat(sbi, &inode->i_mtime, &raw_entry->time,
+ &raw_entry->date, NULL);
+ if (sbi->options.isvfat) {
+ __le16 atime;
+ fat_time_unix2fat(sbi, &inode->i_ctime, &raw_entry->ctime,
+ &raw_entry->cdate, &raw_entry->ctime_cs);
+ fat_time_unix2fat(sbi, &inode->i_atime, &atime,
+ &raw_entry->adate, NULL);
+ }
+ spin_unlock(&sbi->inode_hash_lock);
+ mark_buffer_dirty(bh);
+ err = 0;
+ if (wait)
+ err = sync_dirty_buffer(bh);
+ brelse(bh);
+ return err;
+}
+
+static int fat_write_inode(struct inode *inode, struct writeback_control *wbc)
+{
+ int err;
+
+ if (inode->i_ino == MSDOS_FSINFO_INO) {
+ struct super_block *sb = inode->i_sb;
+
+ mutex_lock(&MSDOS_SB(sb)->s_lock);
+ err = fat_clusters_flush(sb);
+ mutex_unlock(&MSDOS_SB(sb)->s_lock);
+ } else
+ err = __fat_write_inode(inode, wbc->sync_mode == WB_SYNC_ALL);
+
+ return err;
+}
+
+int fat_sync_inode(struct inode *inode)
+{
+ return __fat_write_inode(inode, 1);
+}
+
+EXPORT_SYMBOL_GPL(fat_sync_inode);
+
+static int fat_show_options(struct seq_file *m, struct dentry *root);
+static const struct super_operations fat_sops = {
+ .alloc_inode = fat_alloc_inode,
+ .destroy_inode = fat_destroy_inode,
+ .write_inode = fat_write_inode,
+ .evict_inode = fat_evict_inode,
+ .put_super = fat_put_super,
+ .statfs = fat_statfs,
+ .remount_fs = fat_remount,
+
+ .show_options = fat_show_options,
+};
+
+static int fat_show_options(struct seq_file *m, struct dentry *root)
+{
+ struct msdos_sb_info *sbi = MSDOS_SB(root->d_sb);
+ struct fat_mount_options *opts = &sbi->options;
+ int isvfat = opts->isvfat;
+
+ if (!uid_eq(opts->fs_uid, GLOBAL_ROOT_UID))
+ seq_printf(m, ",uid=%u",
+ from_kuid_munged(&init_user_ns, opts->fs_uid));
+ if (!gid_eq(opts->fs_gid, GLOBAL_ROOT_GID))
+ seq_printf(m, ",gid=%u",
+ from_kgid_munged(&init_user_ns, opts->fs_gid));
+ seq_printf(m, ",fmask=%04o", opts->fs_fmask);
+ seq_printf(m, ",dmask=%04o", opts->fs_dmask);
+ if (opts->allow_utime)
+ seq_printf(m, ",allow_utime=%04o", opts->allow_utime);
+ if (sbi->nls_disk)
+ /* strip "cp" prefix from displayed option */
+ seq_printf(m, ",codepage=%s", &sbi->nls_disk->charset[2]);
+ if (isvfat) {
+ if (sbi->nls_io)
+ seq_printf(m, ",iocharset=%s", sbi->nls_io->charset);
+
+ switch (opts->shortname) {
+ case VFAT_SFN_DISPLAY_WIN95 | VFAT_SFN_CREATE_WIN95:
+ seq_puts(m, ",shortname=win95");
+ break;
+ case VFAT_SFN_DISPLAY_WINNT | VFAT_SFN_CREATE_WINNT:
+ seq_puts(m, ",shortname=winnt");
+ break;
+ case VFAT_SFN_DISPLAY_WINNT | VFAT_SFN_CREATE_WIN95:
+ seq_puts(m, ",shortname=mixed");
+ break;
+ case VFAT_SFN_DISPLAY_LOWER | VFAT_SFN_CREATE_WIN95:
+ seq_puts(m, ",shortname=lower");
+ break;
+ default:
+ seq_puts(m, ",shortname=unknown");
+ break;
+ }
+ }
+ if (opts->name_check != 'n')
+ seq_printf(m, ",check=%c", opts->name_check);
+ if (opts->usefree)
+ seq_puts(m, ",usefree");
+ if (opts->quiet)
+ seq_puts(m, ",quiet");
+ if (opts->showexec)
+ seq_puts(m, ",showexec");
+ if (opts->sys_immutable)
+ seq_puts(m, ",sys_immutable");
+ if (!isvfat) {
+ if (opts->dotsOK)
+ seq_puts(m, ",dotsOK=yes");
+ if (opts->nocase)
+ seq_puts(m, ",nocase");
+ } else {
+ if (opts->utf8)
+ seq_puts(m, ",utf8");
+ if (opts->unicode_xlate)
+ seq_puts(m, ",uni_xlate");
+ if (!opts->numtail)
+ seq_puts(m, ",nonumtail");
+ if (opts->rodir)
+ seq_puts(m, ",rodir");
+ }
+ if (opts->flush)
+ seq_puts(m, ",flush");
+ if (opts->tz_set) {
+ if (opts->time_offset)
+ seq_printf(m, ",time_offset=%d", opts->time_offset);
+ else
+ seq_puts(m, ",tz=UTC");
+ }
+ if (opts->errors == FAT_ERRORS_CONT)
+ seq_puts(m, ",errors=continue");
+ else if (opts->errors == FAT_ERRORS_PANIC)
+ seq_puts(m, ",errors=panic");
+ else
+ seq_puts(m, ",errors=remount-ro");
+ if (opts->nfs == FAT_NFS_NOSTALE_RO)
+ seq_puts(m, ",nfs=nostale_ro");
+ else if (opts->nfs)
+ seq_puts(m, ",nfs=stale_rw");
+ if (opts->discard)
+ seq_puts(m, ",discard");
+ if (opts->dos1xfloppy)
+ seq_puts(m, ",dos1xfloppy");
+
+ return 0;
+}
+
+enum {
+ Opt_check_n, Opt_check_r, Opt_check_s, Opt_uid, Opt_gid,
+ Opt_umask, Opt_dmask, Opt_fmask, Opt_allow_utime, Opt_codepage,
+ Opt_usefree, Opt_nocase, Opt_quiet, Opt_showexec, Opt_debug,
+ Opt_immutable, Opt_dots, Opt_nodots,
+ Opt_charset, Opt_shortname_lower, Opt_shortname_win95,
+ Opt_shortname_winnt, Opt_shortname_mixed, Opt_utf8_no, Opt_utf8_yes,
+ Opt_uni_xl_no, Opt_uni_xl_yes, Opt_nonumtail_no, Opt_nonumtail_yes,
+ Opt_obsolete, Opt_flush, Opt_tz_utc, Opt_rodir, Opt_err_cont,
+ Opt_err_panic, Opt_err_ro, Opt_discard, Opt_nfs, Opt_time_offset,
+ Opt_nfs_stale_rw, Opt_nfs_nostale_ro, Opt_err, Opt_dos1xfloppy,
+};
+
+static const match_table_t fat_tokens = {
+ {Opt_check_r, "check=relaxed"},
+ {Opt_check_s, "check=strict"},
+ {Opt_check_n, "check=normal"},
+ {Opt_check_r, "check=r"},
+ {Opt_check_s, "check=s"},
+ {Opt_check_n, "check=n"},
+ {Opt_uid, "uid=%u"},
+ {Opt_gid, "gid=%u"},
+ {Opt_umask, "umask=%o"},
+ {Opt_dmask, "dmask=%o"},
+ {Opt_fmask, "fmask=%o"},
+ {Opt_allow_utime, "allow_utime=%o"},
+ {Opt_codepage, "codepage=%u"},
+ {Opt_usefree, "usefree"},
+ {Opt_nocase, "nocase"},
+ {Opt_quiet, "quiet"},
+ {Opt_showexec, "showexec"},
+ {Opt_debug, "debug"},
+ {Opt_immutable, "sys_immutable"},
+ {Opt_flush, "flush"},
+ {Opt_tz_utc, "tz=UTC"},
+ {Opt_time_offset, "time_offset=%d"},
+ {Opt_err_cont, "errors=continue"},
+ {Opt_err_panic, "errors=panic"},
+ {Opt_err_ro, "errors=remount-ro"},
+ {Opt_discard, "discard"},
+ {Opt_nfs_stale_rw, "nfs"},
+ {Opt_nfs_stale_rw, "nfs=stale_rw"},
+ {Opt_nfs_nostale_ro, "nfs=nostale_ro"},
+ {Opt_dos1xfloppy, "dos1xfloppy"},
+ {Opt_obsolete, "conv=binary"},
+ {Opt_obsolete, "conv=text"},
+ {Opt_obsolete, "conv=auto"},
+ {Opt_obsolete, "conv=b"},
+ {Opt_obsolete, "conv=t"},
+ {Opt_obsolete, "conv=a"},
+ {Opt_obsolete, "fat=%u"},
+ {Opt_obsolete, "blocksize=%u"},
+ {Opt_obsolete, "cvf_format=%20s"},
+ {Opt_obsolete, "cvf_options=%100s"},
+ {Opt_obsolete, "posix"},
+ {Opt_err, NULL},
+};
+static const match_table_t msdos_tokens = {
+ {Opt_nodots, "nodots"},
+ {Opt_nodots, "dotsOK=no"},
+ {Opt_dots, "dots"},
+ {Opt_dots, "dotsOK=yes"},
+ {Opt_err, NULL}
+};
+static const match_table_t vfat_tokens = {
+ {Opt_charset, "iocharset=%s"},
+ {Opt_shortname_lower, "shortname=lower"},
+ {Opt_shortname_win95, "shortname=win95"},
+ {Opt_shortname_winnt, "shortname=winnt"},
+ {Opt_shortname_mixed, "shortname=mixed"},
+ {Opt_utf8_no, "utf8=0"}, /* 0 or no or false */
+ {Opt_utf8_no, "utf8=no"},
+ {Opt_utf8_no, "utf8=false"},
+ {Opt_utf8_yes, "utf8=1"}, /* empty or 1 or yes or true */
+ {Opt_utf8_yes, "utf8=yes"},
+ {Opt_utf8_yes, "utf8=true"},
+ {Opt_utf8_yes, "utf8"},
+ {Opt_uni_xl_no, "uni_xlate=0"}, /* 0 or no or false */
+ {Opt_uni_xl_no, "uni_xlate=no"},
+ {Opt_uni_xl_no, "uni_xlate=false"},
+ {Opt_uni_xl_yes, "uni_xlate=1"}, /* empty or 1 or yes or true */
+ {Opt_uni_xl_yes, "uni_xlate=yes"},
+ {Opt_uni_xl_yes, "uni_xlate=true"},
+ {Opt_uni_xl_yes, "uni_xlate"},
+ {Opt_nonumtail_no, "nonumtail=0"}, /* 0 or no or false */
+ {Opt_nonumtail_no, "nonumtail=no"},
+ {Opt_nonumtail_no, "nonumtail=false"},
+ {Opt_nonumtail_yes, "nonumtail=1"}, /* empty or 1 or yes or true */
+ {Opt_nonumtail_yes, "nonumtail=yes"},
+ {Opt_nonumtail_yes, "nonumtail=true"},
+ {Opt_nonumtail_yes, "nonumtail"},
+ {Opt_rodir, "rodir"},
+ {Opt_err, NULL}
+};
+
+static int parse_options(struct super_block *sb, char *options, int is_vfat,
+ int silent, int *debug, struct fat_mount_options *opts)
+{
+ char *p;
+ substring_t args[MAX_OPT_ARGS];
+ int option;
+ char *iocharset;
+
+ opts->isvfat = is_vfat;
+
+ opts->fs_uid = current_uid();
+ opts->fs_gid = current_gid();
+ opts->fs_fmask = opts->fs_dmask = current_umask();
+ opts->allow_utime = -1;
+ opts->codepage = fat_default_codepage;
+ fat_reset_iocharset(opts);
+ if (is_vfat) {
+ opts->shortname = VFAT_SFN_DISPLAY_WINNT|VFAT_SFN_CREATE_WIN95;
+ opts->rodir = 0;
+ } else {
+ opts->shortname = 0;
+ opts->rodir = 1;
+ }
+ opts->name_check = 'n';
+ opts->quiet = opts->showexec = opts->sys_immutable = opts->dotsOK = 0;
+ opts->unicode_xlate = 0;
+ opts->numtail = 1;
+ opts->usefree = opts->nocase = 0;
+ opts->tz_set = 0;
+ opts->nfs = 0;
+ opts->errors = FAT_ERRORS_RO;
+ *debug = 0;
+
+ opts->utf8 = IS_ENABLED(CONFIG_FAT_DEFAULT_UTF8) && is_vfat;
+
+ if (!options)
+ goto out;
+
+ while ((p = strsep(&options, ",")) != NULL) {
+ int token;
+ if (!*p)
+ continue;
+
+ token = match_token(p, fat_tokens, args);
+ if (token == Opt_err) {
+ if (is_vfat)
+ token = match_token(p, vfat_tokens, args);
+ else
+ token = match_token(p, msdos_tokens, args);
+ }
+ switch (token) {
+ case Opt_check_s:
+ opts->name_check = 's';
+ break;
+ case Opt_check_r:
+ opts->name_check = 'r';
+ break;
+ case Opt_check_n:
+ opts->name_check = 'n';
+ break;
+ case Opt_usefree:
+ opts->usefree = 1;
+ break;
+ case Opt_nocase:
+ if (!is_vfat)
+ opts->nocase = 1;
+ else {
+ /* for backward compatibility */
+ opts->shortname = VFAT_SFN_DISPLAY_WIN95
+ | VFAT_SFN_CREATE_WIN95;
+ }
+ break;
+ case Opt_quiet:
+ opts->quiet = 1;
+ break;
+ case Opt_showexec:
+ opts->showexec = 1;
+ break;
+ case Opt_debug:
+ *debug = 1;
+ break;
+ case Opt_immutable:
+ opts->sys_immutable = 1;
+ break;
+ case Opt_uid:
+ if (match_int(&args[0], &option))
+ return -EINVAL;
+ opts->fs_uid = make_kuid(current_user_ns(), option);
+ if (!uid_valid(opts->fs_uid))
+ return -EINVAL;
+ break;
+ case Opt_gid:
+ if (match_int(&args[0], &option))
+ return -EINVAL;
+ opts->fs_gid = make_kgid(current_user_ns(), option);
+ if (!gid_valid(opts->fs_gid))
+ return -EINVAL;
+ break;
+ case Opt_umask:
+ if (match_octal(&args[0], &option))
+ return -EINVAL;
+ opts->fs_fmask = opts->fs_dmask = option;
+ break;
+ case Opt_dmask:
+ if (match_octal(&args[0], &option))
+ return -EINVAL;
+ opts->fs_dmask = option;
+ break;
+ case Opt_fmask:
+ if (match_octal(&args[0], &option))
+ return -EINVAL;
+ opts->fs_fmask = option;
+ break;
+ case Opt_allow_utime:
+ if (match_octal(&args[0], &option))
+ return -EINVAL;
+ opts->allow_utime = option & (S_IWGRP | S_IWOTH);
+ break;
+ case Opt_codepage:
+ if (match_int(&args[0], &option))
+ return -EINVAL;
+ opts->codepage = option;
+ break;
+ case Opt_flush:
+ opts->flush = 1;
+ break;
+ case Opt_time_offset:
+ if (match_int(&args[0], &option))
+ return -EINVAL;
+ /*
+ * GMT+-12 zones may have DST corrections so at least
+ * 13 hours difference is needed. Make the limit 24
+ * just in case someone invents something unusual.
+ */
+ if (option < -24 * 60 || option > 24 * 60)
+ return -EINVAL;
+ opts->tz_set = 1;
+ opts->time_offset = option;
+ break;
+ case Opt_tz_utc:
+ opts->tz_set = 1;
+ opts->time_offset = 0;
+ break;
+ case Opt_err_cont:
+ opts->errors = FAT_ERRORS_CONT;
+ break;
+ case Opt_err_panic:
+ opts->errors = FAT_ERRORS_PANIC;
+ break;
+ case Opt_err_ro:
+ opts->errors = FAT_ERRORS_RO;
+ break;
+ case Opt_nfs_stale_rw:
+ opts->nfs = FAT_NFS_STALE_RW;
+ break;
+ case Opt_nfs_nostale_ro:
+ opts->nfs = FAT_NFS_NOSTALE_RO;
+ break;
+ case Opt_dos1xfloppy:
+ opts->dos1xfloppy = 1;
+ break;
+
+ /* msdos specific */
+ case Opt_dots:
+ opts->dotsOK = 1;
+ break;
+ case Opt_nodots:
+ opts->dotsOK = 0;
+ break;
+
+ /* vfat specific */
+ case Opt_charset:
+ fat_reset_iocharset(opts);
+ iocharset = match_strdup(&args[0]);
+ if (!iocharset)
+ return -ENOMEM;
+ opts->iocharset = iocharset;
+ break;
+ case Opt_shortname_lower:
+ opts->shortname = VFAT_SFN_DISPLAY_LOWER
+ | VFAT_SFN_CREATE_WIN95;
+ break;
+ case Opt_shortname_win95:
+ opts->shortname = VFAT_SFN_DISPLAY_WIN95
+ | VFAT_SFN_CREATE_WIN95;
+ break;
+ case Opt_shortname_winnt:
+ opts->shortname = VFAT_SFN_DISPLAY_WINNT
+ | VFAT_SFN_CREATE_WINNT;
+ break;
+ case Opt_shortname_mixed:
+ opts->shortname = VFAT_SFN_DISPLAY_WINNT
+ | VFAT_SFN_CREATE_WIN95;
+ break;
+ case Opt_utf8_no: /* 0 or no or false */
+ opts->utf8 = 0;
+ break;
+ case Opt_utf8_yes: /* empty or 1 or yes or true */
+ opts->utf8 = 1;
+ break;
+ case Opt_uni_xl_no: /* 0 or no or false */
+ opts->unicode_xlate = 0;
+ break;
+ case Opt_uni_xl_yes: /* empty or 1 or yes or true */
+ opts->unicode_xlate = 1;
+ break;
+ case Opt_nonumtail_no: /* 0 or no or false */
+ opts->numtail = 1; /* negated option */
+ break;
+ case Opt_nonumtail_yes: /* empty or 1 or yes or true */
+ opts->numtail = 0; /* negated option */
+ break;
+ case Opt_rodir:
+ opts->rodir = 1;
+ break;
+ case Opt_discard:
+ opts->discard = 1;
+ break;
+
+ /* obsolete mount options */
+ case Opt_obsolete:
+ fat_msg(sb, KERN_INFO, "\"%s\" option is obsolete, "
+ "not supported now", p);
+ break;
+ /* unknown option */
+ default:
+ if (!silent) {
+ fat_msg(sb, KERN_ERR,
+ "Unrecognized mount option \"%s\" "
+ "or missing value", p);
+ }
+ return -EINVAL;
+ }
+ }
+
+out:
+ /* UTF-8 doesn't provide FAT semantics */
+ if (!strcmp(opts->iocharset, "utf8")) {
+ fat_msg(sb, KERN_WARNING, "utf8 is not a recommended IO charset"
+ " for FAT filesystems, filesystem will be "
+ "case sensitive!");
+ }
+
+ /* If user doesn't specify allow_utime, it's initialized from dmask. */
+ if (opts->allow_utime == (unsigned short)-1)
+ opts->allow_utime = ~opts->fs_dmask & (S_IWGRP | S_IWOTH);
+ if (opts->unicode_xlate)
+ opts->utf8 = 0;
+ if (opts->nfs == FAT_NFS_NOSTALE_RO) {
+ sb->s_flags |= SB_RDONLY;
+ sb->s_export_op = &fat_export_ops_nostale;
+ }
+
+ return 0;
+}
+
+static void fat_dummy_inode_init(struct inode *inode)
+{
+ /* Initialize this dummy inode to work as no-op. */
+ MSDOS_I(inode)->mmu_private = 0;
+ MSDOS_I(inode)->i_start = 0;
+ MSDOS_I(inode)->i_logstart = 0;
+ MSDOS_I(inode)->i_attrs = 0;
+ MSDOS_I(inode)->i_pos = 0;
+}
+
+static int fat_read_root(struct inode *inode)
+{
+ struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
+ int error;
+
+ MSDOS_I(inode)->i_pos = MSDOS_ROOT_INO;
+ inode->i_uid = sbi->options.fs_uid;
+ inode->i_gid = sbi->options.fs_gid;
+ inode_inc_iversion(inode);
+ inode->i_generation = 0;
+ inode->i_mode = fat_make_mode(sbi, ATTR_DIR, S_IRWXUGO);
+ inode->i_op = sbi->dir_ops;
+ inode->i_fop = &fat_dir_operations;
+ if (sbi->fat_bits == 32) {
+ MSDOS_I(inode)->i_start = sbi->root_cluster;
+ error = fat_calc_dir_size(inode);
+ if (error < 0)
+ return error;
+ } else {
+ MSDOS_I(inode)->i_start = 0;
+ inode->i_size = sbi->dir_entries * sizeof(struct msdos_dir_entry);
+ }
+ inode->i_blocks = ((inode->i_size + (sbi->cluster_size - 1))
+ & ~((loff_t)sbi->cluster_size - 1)) >> 9;
+ MSDOS_I(inode)->i_logstart = 0;
+ MSDOS_I(inode)->mmu_private = inode->i_size;
+
+ fat_save_attrs(inode, ATTR_DIR);
+ inode->i_mtime.tv_sec = inode->i_atime.tv_sec = inode->i_ctime.tv_sec = 0;
+ inode->i_mtime.tv_nsec = inode->i_atime.tv_nsec = inode->i_ctime.tv_nsec = 0;
+ set_nlink(inode, fat_subdirs(inode)+2);
+
+ return 0;
+}
+
+static unsigned long calc_fat_clusters(struct super_block *sb)
+{
+ struct msdos_sb_info *sbi = MSDOS_SB(sb);
+
+ /* Divide first to avoid overflow */
+ if (sbi->fat_bits != 12) {
+ unsigned long ent_per_sec = sb->s_blocksize * 8 / sbi->fat_bits;
+ return ent_per_sec * sbi->fat_length;
+ }
+
+ return sbi->fat_length * sb->s_blocksize * 8 / sbi->fat_bits;
+}
+
+static bool fat_bpb_is_zero(struct fat_boot_sector *b)
+{
+ if (get_unaligned_le16(&b->sector_size))
+ return false;
+ if (b->sec_per_clus)
+ return false;
+ if (b->reserved)
+ return false;
+ if (b->fats)
+ return false;
+ if (get_unaligned_le16(&b->dir_entries))
+ return false;
+ if (get_unaligned_le16(&b->sectors))
+ return false;
+ if (b->media)
+ return false;
+ if (b->fat_length)
+ return false;
+ if (b->secs_track)
+ return false;
+ if (b->heads)
+ return false;
+ return true;
+}
+
+static int fat_read_bpb(struct super_block *sb, struct fat_boot_sector *b,
+ int silent, struct fat_bios_param_block *bpb)
+{
+ int error = -EINVAL;
+
+ /* Read in BPB ... */
+ memset(bpb, 0, sizeof(*bpb));
+ bpb->fat_sector_size = get_unaligned_le16(&b->sector_size);
+ bpb->fat_sec_per_clus = b->sec_per_clus;
+ bpb->fat_reserved = le16_to_cpu(b->reserved);
+ bpb->fat_fats = b->fats;
+ bpb->fat_dir_entries = get_unaligned_le16(&b->dir_entries);
+ bpb->fat_sectors = get_unaligned_le16(&b->sectors);
+ bpb->fat_fat_length = le16_to_cpu(b->fat_length);
+ bpb->fat_total_sect = le32_to_cpu(b->total_sect);
+
+ bpb->fat16_state = b->fat16.state;
+ bpb->fat16_vol_id = get_unaligned_le32(b->fat16.vol_id);
+
+ bpb->fat32_length = le32_to_cpu(b->fat32.length);
+ bpb->fat32_root_cluster = le32_to_cpu(b->fat32.root_cluster);
+ bpb->fat32_info_sector = le16_to_cpu(b->fat32.info_sector);
+ bpb->fat32_state = b->fat32.state;
+ bpb->fat32_vol_id = get_unaligned_le32(b->fat32.vol_id);
+
+ /* Validate this looks like a FAT filesystem BPB */
+ if (!bpb->fat_reserved) {
+ if (!silent)
+ fat_msg(sb, KERN_ERR,
+ "bogus number of reserved sectors");
+ goto out;
+ }
+ if (!bpb->fat_fats) {
+ if (!silent)
+ fat_msg(sb, KERN_ERR, "bogus number of FAT structure");
+ goto out;
+ }
+
+ /*
+ * Earlier we checked here that b->secs_track and b->head are nonzero,
+ * but it turns out valid FAT filesystems can have zero there.
+ */
+
+ if (!fat_valid_media(b->media)) {
+ if (!silent)
+ fat_msg(sb, KERN_ERR, "invalid media value (0x%02x)",
+ (unsigned)b->media);
+ goto out;
+ }
+
+ if (!is_power_of_2(bpb->fat_sector_size)
+ || (bpb->fat_sector_size < 512)
+ || (bpb->fat_sector_size > 4096)) {
+ if (!silent)
+ fat_msg(sb, KERN_ERR, "bogus logical sector size %u",
+ (unsigned)bpb->fat_sector_size);
+ goto out;
+ }
+
+ if (!is_power_of_2(bpb->fat_sec_per_clus)) {
+ if (!silent)
+ fat_msg(sb, KERN_ERR, "bogus sectors per cluster %u",
+ (unsigned)bpb->fat_sec_per_clus);
+ goto out;
+ }
+
+ error = 0;
+
+out:
+ return error;
+}
+
+static int fat_read_static_bpb(struct super_block *sb,
+ struct fat_boot_sector *b, int silent,
+ struct fat_bios_param_block *bpb)
+{
+ static const char *notdos1x = "This doesn't look like a DOS 1.x volume";
+
+ struct fat_floppy_defaults *fdefaults = NULL;
+ int error = -EINVAL;
+ sector_t bd_sects;
+ unsigned i;
+
+ bd_sects = i_size_read(sb->s_bdev->bd_inode) / SECTOR_SIZE;
+
+ /* 16-bit DOS 1.x reliably wrote bootstrap short-jmp code */
+ if (b->ignored[0] != 0xeb || b->ignored[2] != 0x90) {
+ if (!silent)
+ fat_msg(sb, KERN_ERR,
+ "%s; no bootstrapping code", notdos1x);
+ goto out;
+ }
+
+ /*
+ * If any value in this region is non-zero, it isn't archaic
+ * DOS.
+ */
+ if (!fat_bpb_is_zero(b)) {
+ if (!silent)
+ fat_msg(sb, KERN_ERR,
+ "%s; DOS 2.x BPB is non-zero", notdos1x);
+ goto out;
+ }
+
+ for (i = 0; i < ARRAY_SIZE(floppy_defaults); i++) {
+ if (floppy_defaults[i].nr_sectors == bd_sects) {
+ fdefaults = &floppy_defaults[i];
+ break;
+ }
+ }
+
+ if (fdefaults == NULL) {
+ if (!silent)
+ fat_msg(sb, KERN_WARNING,
+ "This looks like a DOS 1.x volume, but isn't a recognized floppy size (%llu sectors)",
+ (u64)bd_sects);
+ goto out;
+ }
+
+ if (!silent)
+ fat_msg(sb, KERN_INFO,
+ "This looks like a DOS 1.x volume; assuming default BPB values");
+
+ memset(bpb, 0, sizeof(*bpb));
+ bpb->fat_sector_size = SECTOR_SIZE;
+ bpb->fat_sec_per_clus = fdefaults->sec_per_clus;
+ bpb->fat_reserved = 1;
+ bpb->fat_fats = 2;
+ bpb->fat_dir_entries = fdefaults->dir_entries;
+ bpb->fat_sectors = fdefaults->nr_sectors;
+ bpb->fat_fat_length = fdefaults->fat_length;
+
+ error = 0;
+
+out:
+ return error;
+}
+
+/*
+ * Read the super block of an MS-DOS FS.
+ */
+int fat_fill_super(struct super_block *sb, void *data, int silent, int isvfat,
+ void (*setup)(struct super_block *))
+{
+ struct inode *root_inode = NULL, *fat_inode = NULL;
+ struct inode *fsinfo_inode = NULL;
+ struct buffer_head *bh;
+ struct fat_bios_param_block bpb;
+ struct msdos_sb_info *sbi;
+ u16 logical_sector_size;
+ u32 total_sectors, total_clusters, fat_clusters, rootdir_sectors;
+ int debug;
+ long error;
+ char buf[50];
+
+ /*
+ * GFP_KERNEL is ok here, because while we do hold the
+ * superblock lock, memory pressure can't call back into
+ * the filesystem, since we're only just about to mount
+ * it and have no inodes etc active!
+ */
+ sbi = kzalloc(sizeof(struct msdos_sb_info), GFP_KERNEL);
+ if (!sbi)
+ return -ENOMEM;
+ sb->s_fs_info = sbi;
+
+ sb->s_flags |= SB_NODIRATIME;
+ sb->s_magic = MSDOS_SUPER_MAGIC;
+ sb->s_op = &fat_sops;
+ sb->s_export_op = &fat_export_ops;
+ mutex_init(&sbi->nfs_build_inode_lock);
+ ratelimit_state_init(&sbi->ratelimit, DEFAULT_RATELIMIT_INTERVAL,
+ DEFAULT_RATELIMIT_BURST);
+
+ error = parse_options(sb, data, isvfat, silent, &debug, &sbi->options);
+ if (error)
+ goto out_fail;
+
+ setup(sb); /* flavour-specific stuff that needs options */
+
+ error = -EIO;
+ sb_min_blocksize(sb, 512);
+ bh = sb_bread(sb, 0);
+ if (bh == NULL) {
+ fat_msg(sb, KERN_ERR, "unable to read boot sector");
+ goto out_fail;
+ }
+
+ error = fat_read_bpb(sb, (struct fat_boot_sector *)bh->b_data, silent,
+ &bpb);
+ if (error == -EINVAL && sbi->options.dos1xfloppy)
+ error = fat_read_static_bpb(sb,
+ (struct fat_boot_sector *)bh->b_data, silent, &bpb);
+ brelse(bh);
+
+ if (error == -EINVAL)
+ goto out_invalid;
+ else if (error)
+ goto out_fail;
+
+ logical_sector_size = bpb.fat_sector_size;
+ sbi->sec_per_clus = bpb.fat_sec_per_clus;
+
+ error = -EIO;
+ if (logical_sector_size < sb->s_blocksize) {
+ fat_msg(sb, KERN_ERR, "logical sector size too small for device"
+ " (logical sector size = %u)", logical_sector_size);
+ goto out_fail;
+ }
+
+ if (logical_sector_size > sb->s_blocksize) {
+ struct buffer_head *bh_resize;
+
+ if (!sb_set_blocksize(sb, logical_sector_size)) {
+ fat_msg(sb, KERN_ERR, "unable to set blocksize %u",
+ logical_sector_size);
+ goto out_fail;
+ }
+
+ /* Verify that the larger boot sector is fully readable */
+ bh_resize = sb_bread(sb, 0);
+ if (bh_resize == NULL) {
+ fat_msg(sb, KERN_ERR, "unable to read boot sector"
+ " (logical sector size = %lu)",
+ sb->s_blocksize);
+ goto out_fail;
+ }
+ brelse(bh_resize);
+ }
+
+ mutex_init(&sbi->s_lock);
+ sbi->cluster_size = sb->s_blocksize * sbi->sec_per_clus;
+ sbi->cluster_bits = ffs(sbi->cluster_size) - 1;
+ sbi->fats = bpb.fat_fats;
+ sbi->fat_bits = 0; /* Don't know yet */
+ sbi->fat_start = bpb.fat_reserved;
+ sbi->fat_length = bpb.fat_fat_length;
+ sbi->root_cluster = 0;
+ sbi->free_clusters = -1; /* Don't know yet */
+ sbi->free_clus_valid = 0;
+ sbi->prev_free = FAT_START_ENT;
+ sb->s_maxbytes = 0xffffffff;
+
+ if (!sbi->fat_length && bpb.fat32_length) {
+ struct fat_boot_fsinfo *fsinfo;
+ struct buffer_head *fsinfo_bh;
+
+ /* Must be FAT32 */
+ sbi->fat_bits = 32;
+ sbi->fat_length = bpb.fat32_length;
+ sbi->root_cluster = bpb.fat32_root_cluster;
+
+ /* MC - if info_sector is 0, don't multiply by 0 */
+ sbi->fsinfo_sector = bpb.fat32_info_sector;
+ if (sbi->fsinfo_sector == 0)
+ sbi->fsinfo_sector = 1;
+
+ fsinfo_bh = sb_bread(sb, sbi->fsinfo_sector);
+ if (fsinfo_bh == NULL) {
+ fat_msg(sb, KERN_ERR, "bread failed, FSINFO block"
+ " (sector = %lu)", sbi->fsinfo_sector);
+ goto out_fail;
+ }
+
+ fsinfo = (struct fat_boot_fsinfo *)fsinfo_bh->b_data;
+ if (!IS_FSINFO(fsinfo)) {
+ fat_msg(sb, KERN_WARNING, "Invalid FSINFO signature: "
+ "0x%08x, 0x%08x (sector = %lu)",
+ le32_to_cpu(fsinfo->signature1),
+ le32_to_cpu(fsinfo->signature2),
+ sbi->fsinfo_sector);
+ } else {
+ if (sbi->options.usefree)
+ sbi->free_clus_valid = 1;
+ sbi->free_clusters = le32_to_cpu(fsinfo->free_clusters);
+ sbi->prev_free = le32_to_cpu(fsinfo->next_cluster);
+ }
+
+ brelse(fsinfo_bh);
+ }
+
+ /* interpret volume ID as a little endian 32 bit integer */
+ if (sbi->fat_bits == 32)
+ sbi->vol_id = bpb.fat32_vol_id;
+ else /* fat 16 or 12 */
+ sbi->vol_id = bpb.fat16_vol_id;
+
+ sbi->dir_per_block = sb->s_blocksize / sizeof(struct msdos_dir_entry);
+ sbi->dir_per_block_bits = ffs(sbi->dir_per_block) - 1;
+
+ sbi->dir_start = sbi->fat_start + sbi->fats * sbi->fat_length;
+ sbi->dir_entries = bpb.fat_dir_entries;
+ if (sbi->dir_entries & (sbi->dir_per_block - 1)) {
+ if (!silent)
+ fat_msg(sb, KERN_ERR, "bogus number of directory entries"
+ " (%u)", sbi->dir_entries);
+ goto out_invalid;
+ }
+
+ rootdir_sectors = sbi->dir_entries
+ * sizeof(struct msdos_dir_entry) / sb->s_blocksize;
+ sbi->data_start = sbi->dir_start + rootdir_sectors;
+ total_sectors = bpb.fat_sectors;
+ if (total_sectors == 0)
+ total_sectors = bpb.fat_total_sect;
+
+ total_clusters = (total_sectors - sbi->data_start) / sbi->sec_per_clus;
+
+ if (sbi->fat_bits != 32)
+ sbi->fat_bits = (total_clusters > MAX_FAT12) ? 16 : 12;
+
+ /* some OSes set FAT_STATE_DIRTY and clean it on unmount. */
+ if (sbi->fat_bits == 32)
+ sbi->dirty = bpb.fat32_state & FAT_STATE_DIRTY;
+ else /* fat 16 or 12 */
+ sbi->dirty = bpb.fat16_state & FAT_STATE_DIRTY;
+
+ /* check that FAT table does not overflow */
+ fat_clusters = calc_fat_clusters(sb);
+ total_clusters = min(total_clusters, fat_clusters - FAT_START_ENT);
+ if (total_clusters > MAX_FAT(sb)) {
+ if (!silent)
+ fat_msg(sb, KERN_ERR, "count of clusters too big (%u)",
+ total_clusters);
+ goto out_invalid;
+ }
+
+ sbi->max_cluster = total_clusters + FAT_START_ENT;
+ /* check the free_clusters, it's not necessarily correct */
+ if (sbi->free_clusters != -1 && sbi->free_clusters > total_clusters)
+ sbi->free_clusters = -1;
+ /* check the prev_free, it's not necessarily correct */
+ sbi->prev_free %= sbi->max_cluster;
+ if (sbi->prev_free < FAT_START_ENT)
+ sbi->prev_free = FAT_START_ENT;
+
+ /* set up enough so that it can read an inode */
+ fat_hash_init(sb);
+ dir_hash_init(sb);
+ fat_ent_access_init(sb);
+
+ /*
+ * The low byte of FAT's first entry must have same value with
+ * media-field. But in real world, too many devices is
+ * writing wrong value. So, removed that validity check.
+ *
+ * if (FAT_FIRST_ENT(sb, media) != first)
+ */
+
+ error = -EINVAL;
+ sprintf(buf, "cp%d", sbi->options.codepage);
+ sbi->nls_disk = load_nls(buf);
+ if (!sbi->nls_disk) {
+ fat_msg(sb, KERN_ERR, "codepage %s not found", buf);
+ goto out_fail;
+ }
+
+ /* FIXME: utf8 is using iocharset for upper/lower conversion */
+ if (sbi->options.isvfat) {
+ sbi->nls_io = load_nls(sbi->options.iocharset);
+ if (!sbi->nls_io) {
+ fat_msg(sb, KERN_ERR, "IO charset %s not found",
+ sbi->options.iocharset);
+ goto out_fail;
+ }
+ }
+
+ error = -ENOMEM;
+ fat_inode = new_inode(sb);
+ if (!fat_inode)
+ goto out_fail;
+ fat_dummy_inode_init(fat_inode);
+ sbi->fat_inode = fat_inode;
+
+ fsinfo_inode = new_inode(sb);
+ if (!fsinfo_inode)
+ goto out_fail;
+ fat_dummy_inode_init(fsinfo_inode);
+ fsinfo_inode->i_ino = MSDOS_FSINFO_INO;
+ sbi->fsinfo_inode = fsinfo_inode;
+ insert_inode_hash(fsinfo_inode);
+
+ root_inode = new_inode(sb);
+ if (!root_inode)
+ goto out_fail;
+ root_inode->i_ino = MSDOS_ROOT_INO;
+ inode_set_iversion(root_inode, 1);
+ error = fat_read_root(root_inode);
+ if (error < 0) {
+ iput(root_inode);
+ goto out_fail;
+ }
+ error = -ENOMEM;
+ insert_inode_hash(root_inode);
+ fat_attach(root_inode, 0);
+ sb->s_root = d_make_root(root_inode);
+ if (!sb->s_root) {
+ fat_msg(sb, KERN_ERR, "get root inode failed");
+ goto out_fail;
+ }
+
+ if (sbi->options.discard) {
+ struct request_queue *q = bdev_get_queue(sb->s_bdev);
+ if (!blk_queue_discard(q))
+ fat_msg(sb, KERN_WARNING,
+ "mounting with \"discard\" option, but "
+ "the device does not support discard");
+ }
+
+ fat_set_state(sb, 1, 0);
+ return 0;
+
+out_invalid:
+ error = -EINVAL;
+ if (!silent)
+ fat_msg(sb, KERN_INFO, "Can't find a valid FAT filesystem");
+
+out_fail:
+ if (fsinfo_inode)
+ iput(fsinfo_inode);
+ if (fat_inode)
+ iput(fat_inode);
+ unload_nls(sbi->nls_io);
+ unload_nls(sbi->nls_disk);
+ fat_reset_iocharset(&sbi->options);
+ sb->s_fs_info = NULL;
+ kfree(sbi);
+ return error;
+}
+
+EXPORT_SYMBOL_GPL(fat_fill_super);
+
+/*
+ * helper function for fat_flush_inodes. This writes both the inode
+ * and the file data blocks, waiting for in flight data blocks before
+ * the start of the call. It does not wait for any io started
+ * during the call
+ */
+static int writeback_inode(struct inode *inode)
+{
+
+ int ret;
+
+ /* if we used wait=1, sync_inode_metadata waits for the io for the
+ * inode to finish. So wait=0 is sent down to sync_inode_metadata
+ * and filemap_fdatawrite is used for the data blocks
+ */
+ ret = sync_inode_metadata(inode, 0);
+ if (!ret)
+ ret = filemap_fdatawrite(inode->i_mapping);
+ return ret;
+}
+
+/*
+ * write data and metadata corresponding to i1 and i2. The io is
+ * started but we do not wait for any of it to finish.
+ *
+ * filemap_flush is used for the block device, so if there is a dirty
+ * page for a block already in flight, we will not wait and start the
+ * io over again
+ */
+int fat_flush_inodes(struct super_block *sb, struct inode *i1, struct inode *i2)
+{
+ int ret = 0;
+ if (!MSDOS_SB(sb)->options.flush)
+ return 0;
+ if (i1)
+ ret = writeback_inode(i1);
+ if (!ret && i2)
+ ret = writeback_inode(i2);
+ if (!ret) {
+ struct address_space *mapping = sb->s_bdev->bd_inode->i_mapping;
+ ret = filemap_flush(mapping);
+ }
+ return ret;
+}
+EXPORT_SYMBOL_GPL(fat_flush_inodes);
+
+static int __init init_fat_fs(void)
+{
+ int err;
+
+ err = fat_cache_init();
+ if (err)
+ return err;
+
+ err = fat_init_inodecache();
+ if (err)
+ goto failed;
+
+ return 0;
+
+failed:
+ fat_cache_destroy();
+ return err;
+}
+
+static void __exit exit_fat_fs(void)
+{
+ fat_cache_destroy();
+ fat_destroy_inodecache();
+}
+
+module_init(init_fat_fs)
+module_exit(exit_fat_fs)
+
+MODULE_LICENSE("GPL");
diff --git a/fs/fat/misc.c b/fs/fat/misc.c
new file mode 100644
index 0000000..573836d
--- /dev/null
+++ b/fs/fat/misc.c
@@ -0,0 +1,279 @@
+/*
+ * linux/fs/fat/misc.c
+ *
+ * Written 1992,1993 by Werner Almesberger
+ * 22/11/2000 - Fixed fat_date_unix2dos for dates earlier than 01/01/1980
+ * and date_dos2unix for date==0 by Igor Zhbanov(bsg@uniyar.ac.ru)
+ */
+
+#include "fat.h"
+
+/*
+ * fat_fs_error reports a file system problem that might indicate fa data
+ * corruption/inconsistency. Depending on 'errors' mount option the
+ * panic() is called, or error message is printed FAT and nothing is done,
+ * or filesystem is remounted read-only (default behavior).
+ * In case the file system is remounted read-only, it can be made writable
+ * again by remounting it.
+ */
+void __fat_fs_error(struct super_block *sb, int report, const char *fmt, ...)
+{
+ struct fat_mount_options *opts = &MSDOS_SB(sb)->options;
+ va_list args;
+ struct va_format vaf;
+
+ if (report) {
+ va_start(args, fmt);
+ vaf.fmt = fmt;
+ vaf.va = &args;
+ fat_msg(sb, KERN_ERR, "error, %pV", &vaf);
+ va_end(args);
+ }
+
+ if (opts->errors == FAT_ERRORS_PANIC)
+ panic("FAT-fs (%s): fs panic from previous error\n", sb->s_id);
+ else if (opts->errors == FAT_ERRORS_RO && !sb_rdonly(sb)) {
+ sb->s_flags |= SB_RDONLY;
+ fat_msg(sb, KERN_ERR, "Filesystem has been set read-only");
+ }
+}
+EXPORT_SYMBOL_GPL(__fat_fs_error);
+
+/**
+ * fat_msg() - print preformated FAT specific messages. Every thing what is
+ * not fat_fs_error() should be fat_msg().
+ */
+void fat_msg(struct super_block *sb, const char *level, const char *fmt, ...)
+{
+ struct va_format vaf;
+ va_list args;
+
+ va_start(args, fmt);
+ vaf.fmt = fmt;
+ vaf.va = &args;
+ printk("%sFAT-fs (%s): %pV\n", level, sb->s_id, &vaf);
+ va_end(args);
+}
+
+/* Flushes the number of free clusters on FAT32 */
+/* XXX: Need to write one per FSINFO block. Currently only writes 1 */
+int fat_clusters_flush(struct super_block *sb)
+{
+ struct msdos_sb_info *sbi = MSDOS_SB(sb);
+ struct buffer_head *bh;
+ struct fat_boot_fsinfo *fsinfo;
+
+ if (sbi->fat_bits != 32)
+ return 0;
+
+ bh = sb_bread(sb, sbi->fsinfo_sector);
+ if (bh == NULL) {
+ fat_msg(sb, KERN_ERR, "bread failed in fat_clusters_flush");
+ return -EIO;
+ }
+
+ fsinfo = (struct fat_boot_fsinfo *)bh->b_data;
+ /* Sanity check */
+ if (!IS_FSINFO(fsinfo)) {
+ fat_msg(sb, KERN_ERR, "Invalid FSINFO signature: "
+ "0x%08x, 0x%08x (sector = %lu)",
+ le32_to_cpu(fsinfo->signature1),
+ le32_to_cpu(fsinfo->signature2),
+ sbi->fsinfo_sector);
+ } else {
+ if (sbi->free_clusters != -1)
+ fsinfo->free_clusters = cpu_to_le32(sbi->free_clusters);
+ if (sbi->prev_free != -1)
+ fsinfo->next_cluster = cpu_to_le32(sbi->prev_free);
+ mark_buffer_dirty(bh);
+ }
+ brelse(bh);
+
+ return 0;
+}
+
+/*
+ * fat_chain_add() adds a new cluster to the chain of clusters represented
+ * by inode.
+ */
+int fat_chain_add(struct inode *inode, int new_dclus, int nr_cluster)
+{
+ struct super_block *sb = inode->i_sb;
+ struct msdos_sb_info *sbi = MSDOS_SB(sb);
+ int ret, new_fclus, last;
+
+ /*
+ * We must locate the last cluster of the file to add this new
+ * one (new_dclus) to the end of the link list (the FAT).
+ */
+ last = new_fclus = 0;
+ if (MSDOS_I(inode)->i_start) {
+ int fclus, dclus;
+
+ ret = fat_get_cluster(inode, FAT_ENT_EOF, &fclus, &dclus);
+ if (ret < 0)
+ return ret;
+ new_fclus = fclus + 1;
+ last = dclus;
+ }
+
+ /* add new one to the last of the cluster chain */
+ if (last) {
+ struct fat_entry fatent;
+
+ fatent_init(&fatent);
+ ret = fat_ent_read(inode, &fatent, last);
+ if (ret >= 0) {
+ int wait = inode_needs_sync(inode);
+ ret = fat_ent_write(inode, &fatent, new_dclus, wait);
+ fatent_brelse(&fatent);
+ }
+ if (ret < 0)
+ return ret;
+ /*
+ * FIXME:Although we can add this cache, fat_cache_add() is
+ * assuming to be called after linear search with fat_cache_id.
+ */
+// fat_cache_add(inode, new_fclus, new_dclus);
+ } else {
+ MSDOS_I(inode)->i_start = new_dclus;
+ MSDOS_I(inode)->i_logstart = new_dclus;
+ /*
+ * Since generic_write_sync() synchronizes regular files later,
+ * we sync here only directories.
+ */
+ if (S_ISDIR(inode->i_mode) && IS_DIRSYNC(inode)) {
+ ret = fat_sync_inode(inode);
+ if (ret)
+ return ret;
+ } else
+ mark_inode_dirty(inode);
+ }
+ if (new_fclus != (inode->i_blocks >> (sbi->cluster_bits - 9))) {
+ fat_fs_error(sb, "clusters badly computed (%d != %llu)",
+ new_fclus,
+ (llu)(inode->i_blocks >> (sbi->cluster_bits - 9)));
+ fat_cache_inval_inode(inode);
+ }
+ inode->i_blocks += nr_cluster << (sbi->cluster_bits - 9);
+
+ return 0;
+}
+
+/*
+ * The epoch of FAT timestamp is 1980.
+ * : bits : value
+ * date: 0 - 4: day (1 - 31)
+ * date: 5 - 8: month (1 - 12)
+ * date: 9 - 15: year (0 - 127) from 1980
+ * time: 0 - 4: sec (0 - 29) 2sec counts
+ * time: 5 - 10: min (0 - 59)
+ * time: 11 - 15: hour (0 - 23)
+ */
+#define SECS_PER_MIN 60
+#define SECS_PER_HOUR (60 * 60)
+#define SECS_PER_DAY (SECS_PER_HOUR * 24)
+/* days between 1.1.70 and 1.1.80 (2 leap days) */
+#define DAYS_DELTA (365 * 10 + 2)
+/* 120 (2100 - 1980) isn't leap year */
+#define YEAR_2100 120
+#define IS_LEAP_YEAR(y) (!((y) & 3) && (y) != YEAR_2100)
+
+/* Linear day numbers of the respective 1sts in non-leap years. */
+static long days_in_year[] = {
+ /* Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec */
+ 0, 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 0, 0, 0,
+};
+
+/* Convert a FAT time/date pair to a UNIX date (seconds since 1 1 70). */
+void fat_time_fat2unix(struct msdos_sb_info *sbi, struct timespec64 *ts,
+ __le16 __time, __le16 __date, u8 time_cs)
+{
+ u16 time = le16_to_cpu(__time), date = le16_to_cpu(__date);
+ time64_t second;
+ long day, leap_day, month, year;
+
+ year = date >> 9;
+ month = max(1, (date >> 5) & 0xf);
+ day = max(1, date & 0x1f) - 1;
+
+ leap_day = (year + 3) / 4;
+ if (year > YEAR_2100) /* 2100 isn't leap year */
+ leap_day--;
+ if (IS_LEAP_YEAR(year) && month > 2)
+ leap_day++;
+
+ second = (time & 0x1f) << 1;
+ second += ((time >> 5) & 0x3f) * SECS_PER_MIN;
+ second += (time >> 11) * SECS_PER_HOUR;
+ second += (time64_t)(year * 365 + leap_day
+ + days_in_year[month] + day
+ + DAYS_DELTA) * SECS_PER_DAY;
+
+ if (!sbi->options.tz_set)
+ second += sys_tz.tz_minuteswest * SECS_PER_MIN;
+ else
+ second -= sbi->options.time_offset * SECS_PER_MIN;
+
+ if (time_cs) {
+ ts->tv_sec = second + (time_cs / 100);
+ ts->tv_nsec = (time_cs % 100) * 10000000;
+ } else {
+ ts->tv_sec = second;
+ ts->tv_nsec = 0;
+ }
+}
+
+/* Convert linear UNIX date to a FAT time/date pair. */
+void fat_time_unix2fat(struct msdos_sb_info *sbi, struct timespec64 *ts,
+ __le16 *time, __le16 *date, u8 *time_cs)
+{
+ struct tm tm;
+ time64_to_tm(ts->tv_sec,
+ (sbi->options.tz_set ? sbi->options.time_offset :
+ -sys_tz.tz_minuteswest) * SECS_PER_MIN, &tm);
+
+ /* FAT can only support year between 1980 to 2107 */
+ if (tm.tm_year < 1980 - 1900) {
+ *time = 0;
+ *date = cpu_to_le16((0 << 9) | (1 << 5) | 1);
+ if (time_cs)
+ *time_cs = 0;
+ return;
+ }
+ if (tm.tm_year > 2107 - 1900) {
+ *time = cpu_to_le16((23 << 11) | (59 << 5) | 29);
+ *date = cpu_to_le16((127 << 9) | (12 << 5) | 31);
+ if (time_cs)
+ *time_cs = 199;
+ return;
+ }
+
+ /* from 1900 -> from 1980 */
+ tm.tm_year -= 80;
+ /* 0~11 -> 1~12 */
+ tm.tm_mon++;
+ /* 0~59 -> 0~29(2sec counts) */
+ tm.tm_sec >>= 1;
+
+ *time = cpu_to_le16(tm.tm_hour << 11 | tm.tm_min << 5 | tm.tm_sec);
+ *date = cpu_to_le16(tm.tm_year << 9 | tm.tm_mon << 5 | tm.tm_mday);
+ if (time_cs)
+ *time_cs = (ts->tv_sec & 1) * 100 + ts->tv_nsec / 10000000;
+}
+EXPORT_SYMBOL_GPL(fat_time_unix2fat);
+
+int fat_sync_bhs(struct buffer_head **bhs, int nr_bhs)
+{
+ int i, err = 0;
+
+ for (i = 0; i < nr_bhs; i++)
+ write_dirty_buffer(bhs[i], 0);
+
+ for (i = 0; i < nr_bhs; i++) {
+ wait_on_buffer(bhs[i]);
+ if (!err && !buffer_uptodate(bhs[i]))
+ err = -EIO;
+ }
+ return err;
+}
diff --git a/fs/fat/namei_msdos.c b/fs/fat/namei_msdos.c
new file mode 100644
index 0000000..efb8c40
--- /dev/null
+++ b/fs/fat/namei_msdos.c
@@ -0,0 +1,685 @@
+/*
+ * linux/fs/msdos/namei.c
+ *
+ * Written 1992,1993 by Werner Almesberger
+ * Hidden files 1995 by Albert Cahalan <albert@ccs.neu.edu> <adc@coe.neu.edu>
+ * Rewritten for constant inumbers 1999 by Al Viro
+ */
+
+#include <linux/module.h>
+#include <linux/iversion.h>
+#include "fat.h"
+
+/* Characters that are undesirable in an MS-DOS file name */
+static unsigned char bad_chars[] = "*?<>|\"";
+static unsigned char bad_if_strict[] = "+=,; ";
+
+/***** Formats an MS-DOS file name. Rejects invalid names. */
+static int msdos_format_name(const unsigned char *name, int len,
+ unsigned char *res, struct fat_mount_options *opts)
+ /*
+ * name is the proposed name, len is its length, res is
+ * the resulting name, opts->name_check is either (r)elaxed,
+ * (n)ormal or (s)trict, opts->dotsOK allows dots at the
+ * beginning of name (for hidden files)
+ */
+{
+ unsigned char *walk;
+ unsigned char c;
+ int space;
+
+ if (name[0] == '.') { /* dotfile because . and .. already done */
+ if (opts->dotsOK) {
+ /* Get rid of dot - test for it elsewhere */
+ name++;
+ len--;
+ } else
+ return -EINVAL;
+ }
+ /*
+ * disallow names that _really_ start with a dot
+ */
+ space = 1;
+ c = 0;
+ for (walk = res; len && walk - res < 8; walk++) {
+ c = *name++;
+ len--;
+ if (opts->name_check != 'r' && strchr(bad_chars, c))
+ return -EINVAL;
+ if (opts->name_check == 's' && strchr(bad_if_strict, c))
+ return -EINVAL;
+ if (c >= 'A' && c <= 'Z' && opts->name_check == 's')
+ return -EINVAL;
+ if (c < ' ' || c == ':' || c == '\\')
+ return -EINVAL;
+ /*
+ * 0xE5 is legal as a first character, but we must substitute
+ * 0x05 because 0xE5 marks deleted files. Yes, DOS really
+ * does this.
+ * It seems that Microsoft hacked DOS to support non-US
+ * characters after the 0xE5 character was already in use to
+ * mark deleted files.
+ */
+ if ((res == walk) && (c == 0xE5))
+ c = 0x05;
+ if (c == '.')
+ break;
+ space = (c == ' ');
+ *walk = (!opts->nocase && c >= 'a' && c <= 'z') ? c - 32 : c;
+ }
+ if (space)
+ return -EINVAL;
+ if (opts->name_check == 's' && len && c != '.') {
+ c = *name++;
+ len--;
+ if (c != '.')
+ return -EINVAL;
+ }
+ while (c != '.' && len--)
+ c = *name++;
+ if (c == '.') {
+ while (walk - res < 8)
+ *walk++ = ' ';
+ while (len > 0 && walk - res < MSDOS_NAME) {
+ c = *name++;
+ len--;
+ if (opts->name_check != 'r' && strchr(bad_chars, c))
+ return -EINVAL;
+ if (opts->name_check == 's' &&
+ strchr(bad_if_strict, c))
+ return -EINVAL;
+ if (c < ' ' || c == ':' || c == '\\')
+ return -EINVAL;
+ if (c == '.') {
+ if (opts->name_check == 's')
+ return -EINVAL;
+ break;
+ }
+ if (c >= 'A' && c <= 'Z' && opts->name_check == 's')
+ return -EINVAL;
+ space = c == ' ';
+ if (!opts->nocase && c >= 'a' && c <= 'z')
+ *walk++ = c - 32;
+ else
+ *walk++ = c;
+ }
+ if (space)
+ return -EINVAL;
+ if (opts->name_check == 's' && len)
+ return -EINVAL;
+ }
+ while (walk - res < MSDOS_NAME)
+ *walk++ = ' ';
+
+ return 0;
+}
+
+/***** Locates a directory entry. Uses unformatted name. */
+static int msdos_find(struct inode *dir, const unsigned char *name, int len,
+ struct fat_slot_info *sinfo)
+{
+ struct msdos_sb_info *sbi = MSDOS_SB(dir->i_sb);
+ unsigned char msdos_name[MSDOS_NAME];
+ int err;
+
+ err = msdos_format_name(name, len, msdos_name, &sbi->options);
+ if (err)
+ return -ENOENT;
+
+ err = fat_scan(dir, msdos_name, sinfo);
+ if (!err && sbi->options.dotsOK) {
+ if (name[0] == '.') {
+ if (!(sinfo->de->attr & ATTR_HIDDEN))
+ err = -ENOENT;
+ } else {
+ if (sinfo->de->attr & ATTR_HIDDEN)
+ err = -ENOENT;
+ }
+ if (err)
+ brelse(sinfo->bh);
+ }
+ return err;
+}
+
+/*
+ * Compute the hash for the msdos name corresponding to the dentry.
+ * Note: if the name is invalid, we leave the hash code unchanged so
+ * that the existing dentry can be used. The msdos fs routines will
+ * return ENOENT or EINVAL as appropriate.
+ */
+static int msdos_hash(const struct dentry *dentry, struct qstr *qstr)
+{
+ struct fat_mount_options *options = &MSDOS_SB(dentry->d_sb)->options;
+ unsigned char msdos_name[MSDOS_NAME];
+ int error;
+
+ error = msdos_format_name(qstr->name, qstr->len, msdos_name, options);
+ if (!error)
+ qstr->hash = full_name_hash(dentry, msdos_name, MSDOS_NAME);
+ return 0;
+}
+
+/*
+ * Compare two msdos names. If either of the names are invalid,
+ * we fall back to doing the standard name comparison.
+ */
+static int msdos_cmp(const struct dentry *dentry,
+ unsigned int len, const char *str, const struct qstr *name)
+{
+ struct fat_mount_options *options = &MSDOS_SB(dentry->d_sb)->options;
+ unsigned char a_msdos_name[MSDOS_NAME], b_msdos_name[MSDOS_NAME];
+ int error;
+
+ error = msdos_format_name(name->name, name->len, a_msdos_name, options);
+ if (error)
+ goto old_compare;
+ error = msdos_format_name(str, len, b_msdos_name, options);
+ if (error)
+ goto old_compare;
+ error = memcmp(a_msdos_name, b_msdos_name, MSDOS_NAME);
+out:
+ return error;
+
+old_compare:
+ error = 1;
+ if (name->len == len)
+ error = memcmp(name->name, str, len);
+ goto out;
+}
+
+static const struct dentry_operations msdos_dentry_operations = {
+ .d_hash = msdos_hash,
+ .d_compare = msdos_cmp,
+};
+
+/*
+ * AV. Wrappers for FAT sb operations. Is it wise?
+ */
+
+/***** Get inode using directory and name */
+static struct dentry *msdos_lookup(struct inode *dir, struct dentry *dentry,
+ unsigned int flags)
+{
+ struct super_block *sb = dir->i_sb;
+ struct fat_slot_info sinfo;
+ struct inode *inode;
+ int err;
+
+ mutex_lock(&MSDOS_SB(sb)->s_lock);
+ err = msdos_find(dir, dentry->d_name.name, dentry->d_name.len, &sinfo);
+ switch (err) {
+ case -ENOENT:
+ inode = NULL;
+ break;
+ case 0:
+ inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
+ brelse(sinfo.bh);
+ break;
+ default:
+ inode = ERR_PTR(err);
+ }
+ mutex_unlock(&MSDOS_SB(sb)->s_lock);
+ return d_splice_alias(inode, dentry);
+}
+
+/***** Creates a directory entry (name is already formatted). */
+static int msdos_add_entry(struct inode *dir, const unsigned char *name,
+ int is_dir, int is_hid, int cluster,
+ struct timespec64 *ts, struct fat_slot_info *sinfo)
+{
+ struct msdos_sb_info *sbi = MSDOS_SB(dir->i_sb);
+ struct msdos_dir_entry de;
+ __le16 time, date;
+ int err;
+
+ memcpy(de.name, name, MSDOS_NAME);
+ de.attr = is_dir ? ATTR_DIR : ATTR_ARCH;
+ if (is_hid)
+ de.attr |= ATTR_HIDDEN;
+ de.lcase = 0;
+ fat_time_unix2fat(sbi, ts, &time, &date, NULL);
+ de.cdate = de.adate = 0;
+ de.ctime = 0;
+ de.ctime_cs = 0;
+ de.time = time;
+ de.date = date;
+ fat_set_start(&de, cluster);
+ de.size = 0;
+
+ err = fat_add_entries(dir, &de, 1, sinfo);
+ if (err)
+ return err;
+
+ dir->i_ctime = dir->i_mtime = *ts;
+ if (IS_DIRSYNC(dir))
+ (void)fat_sync_inode(dir);
+ else
+ mark_inode_dirty(dir);
+
+ return 0;
+}
+
+/***** Create a file */
+static int msdos_create(struct inode *dir, struct dentry *dentry, umode_t mode,
+ bool excl)
+{
+ struct super_block *sb = dir->i_sb;
+ struct inode *inode = NULL;
+ struct fat_slot_info sinfo;
+ struct timespec64 ts;
+ unsigned char msdos_name[MSDOS_NAME];
+ int err, is_hid;
+
+ mutex_lock(&MSDOS_SB(sb)->s_lock);
+
+ err = msdos_format_name(dentry->d_name.name, dentry->d_name.len,
+ msdos_name, &MSDOS_SB(sb)->options);
+ if (err)
+ goto out;
+ is_hid = (dentry->d_name.name[0] == '.') && (msdos_name[0] != '.');
+ /* Have to do it due to foo vs. .foo conflicts */
+ if (!fat_scan(dir, msdos_name, &sinfo)) {
+ brelse(sinfo.bh);
+ err = -EINVAL;
+ goto out;
+ }
+
+ ts = current_time(dir);
+ err = msdos_add_entry(dir, msdos_name, 0, is_hid, 0, &ts, &sinfo);
+ if (err)
+ goto out;
+ inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
+ brelse(sinfo.bh);
+ if (IS_ERR(inode)) {
+ err = PTR_ERR(inode);
+ goto out;
+ }
+ inode->i_mtime = inode->i_atime = inode->i_ctime = ts;
+ /* timestamp is already written, so mark_inode_dirty() is unneeded. */
+
+ d_instantiate(dentry, inode);
+out:
+ mutex_unlock(&MSDOS_SB(sb)->s_lock);
+ if (!err)
+ err = fat_flush_inodes(sb, dir, inode);
+ return err;
+}
+
+/***** Remove a directory */
+static int msdos_rmdir(struct inode *dir, struct dentry *dentry)
+{
+ struct super_block *sb = dir->i_sb;
+ struct inode *inode = d_inode(dentry);
+ struct fat_slot_info sinfo;
+ int err;
+
+ mutex_lock(&MSDOS_SB(sb)->s_lock);
+ err = fat_dir_empty(inode);
+ if (err)
+ goto out;
+ err = msdos_find(dir, dentry->d_name.name, dentry->d_name.len, &sinfo);
+ if (err)
+ goto out;
+
+ err = fat_remove_entries(dir, &sinfo); /* and releases bh */
+ if (err)
+ goto out;
+ drop_nlink(dir);
+
+ clear_nlink(inode);
+ inode->i_ctime = current_time(inode);
+ fat_detach(inode);
+out:
+ mutex_unlock(&MSDOS_SB(sb)->s_lock);
+ if (!err)
+ err = fat_flush_inodes(sb, dir, inode);
+
+ return err;
+}
+
+/***** Make a directory */
+static int msdos_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
+{
+ struct super_block *sb = dir->i_sb;
+ struct fat_slot_info sinfo;
+ struct inode *inode;
+ unsigned char msdos_name[MSDOS_NAME];
+ struct timespec64 ts;
+ int err, is_hid, cluster;
+
+ mutex_lock(&MSDOS_SB(sb)->s_lock);
+
+ err = msdos_format_name(dentry->d_name.name, dentry->d_name.len,
+ msdos_name, &MSDOS_SB(sb)->options);
+ if (err)
+ goto out;
+ is_hid = (dentry->d_name.name[0] == '.') && (msdos_name[0] != '.');
+ /* foo vs .foo situation */
+ if (!fat_scan(dir, msdos_name, &sinfo)) {
+ brelse(sinfo.bh);
+ err = -EINVAL;
+ goto out;
+ }
+
+ ts = current_time(dir);
+ cluster = fat_alloc_new_dir(dir, &ts);
+ if (cluster < 0) {
+ err = cluster;
+ goto out;
+ }
+ err = msdos_add_entry(dir, msdos_name, 1, is_hid, cluster, &ts, &sinfo);
+ if (err)
+ goto out_free;
+ inc_nlink(dir);
+
+ inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
+ brelse(sinfo.bh);
+ if (IS_ERR(inode)) {
+ err = PTR_ERR(inode);
+ /* the directory was completed, just return a error */
+ goto out;
+ }
+ set_nlink(inode, 2);
+ inode->i_mtime = inode->i_atime = inode->i_ctime = ts;
+ /* timestamp is already written, so mark_inode_dirty() is unneeded. */
+
+ d_instantiate(dentry, inode);
+
+ mutex_unlock(&MSDOS_SB(sb)->s_lock);
+ fat_flush_inodes(sb, dir, inode);
+ return 0;
+
+out_free:
+ fat_free_clusters(dir, cluster);
+out:
+ mutex_unlock(&MSDOS_SB(sb)->s_lock);
+ return err;
+}
+
+/***** Unlink a file */
+static int msdos_unlink(struct inode *dir, struct dentry *dentry)
+{
+ struct inode *inode = d_inode(dentry);
+ struct super_block *sb = inode->i_sb;
+ struct fat_slot_info sinfo;
+ int err;
+
+ mutex_lock(&MSDOS_SB(sb)->s_lock);
+ err = msdos_find(dir, dentry->d_name.name, dentry->d_name.len, &sinfo);
+ if (err)
+ goto out;
+
+ err = fat_remove_entries(dir, &sinfo); /* and releases bh */
+ if (err)
+ goto out;
+ clear_nlink(inode);
+ inode->i_ctime = current_time(inode);
+ fat_detach(inode);
+out:
+ mutex_unlock(&MSDOS_SB(sb)->s_lock);
+ if (!err)
+ err = fat_flush_inodes(sb, dir, inode);
+
+ return err;
+}
+
+static int do_msdos_rename(struct inode *old_dir, unsigned char *old_name,
+ struct dentry *old_dentry,
+ struct inode *new_dir, unsigned char *new_name,
+ struct dentry *new_dentry, int is_hid)
+{
+ struct buffer_head *dotdot_bh;
+ struct msdos_dir_entry *dotdot_de;
+ struct inode *old_inode, *new_inode;
+ struct fat_slot_info old_sinfo, sinfo;
+ struct timespec64 ts;
+ loff_t new_i_pos;
+ int err, old_attrs, is_dir, update_dotdot, corrupt = 0;
+
+ old_sinfo.bh = sinfo.bh = dotdot_bh = NULL;
+ old_inode = d_inode(old_dentry);
+ new_inode = d_inode(new_dentry);
+
+ err = fat_scan(old_dir, old_name, &old_sinfo);
+ if (err) {
+ err = -EIO;
+ goto out;
+ }
+
+ is_dir = S_ISDIR(old_inode->i_mode);
+ update_dotdot = (is_dir && old_dir != new_dir);
+ if (update_dotdot) {
+ if (fat_get_dotdot_entry(old_inode, &dotdot_bh, &dotdot_de)) {
+ err = -EIO;
+ goto out;
+ }
+ }
+
+ old_attrs = MSDOS_I(old_inode)->i_attrs;
+ err = fat_scan(new_dir, new_name, &sinfo);
+ if (!err) {
+ if (!new_inode) {
+ /* "foo" -> ".foo" case. just change the ATTR_HIDDEN */
+ if (sinfo.de != old_sinfo.de) {
+ err = -EINVAL;
+ goto out;
+ }
+ if (is_hid)
+ MSDOS_I(old_inode)->i_attrs |= ATTR_HIDDEN;
+ else
+ MSDOS_I(old_inode)->i_attrs &= ~ATTR_HIDDEN;
+ if (IS_DIRSYNC(old_dir)) {
+ err = fat_sync_inode(old_inode);
+ if (err) {
+ MSDOS_I(old_inode)->i_attrs = old_attrs;
+ goto out;
+ }
+ } else
+ mark_inode_dirty(old_inode);
+
+ inode_inc_iversion(old_dir);
+ old_dir->i_ctime = old_dir->i_mtime = current_time(old_dir);
+ if (IS_DIRSYNC(old_dir))
+ (void)fat_sync_inode(old_dir);
+ else
+ mark_inode_dirty(old_dir);
+ goto out;
+ }
+ }
+
+ ts = current_time(old_inode);
+ if (new_inode) {
+ if (err)
+ goto out;
+ if (is_dir) {
+ err = fat_dir_empty(new_inode);
+ if (err)
+ goto out;
+ }
+ new_i_pos = MSDOS_I(new_inode)->i_pos;
+ fat_detach(new_inode);
+ } else {
+ err = msdos_add_entry(new_dir, new_name, is_dir, is_hid, 0,
+ &ts, &sinfo);
+ if (err)
+ goto out;
+ new_i_pos = sinfo.i_pos;
+ }
+ inode_inc_iversion(new_dir);
+
+ fat_detach(old_inode);
+ fat_attach(old_inode, new_i_pos);
+ if (is_hid)
+ MSDOS_I(old_inode)->i_attrs |= ATTR_HIDDEN;
+ else
+ MSDOS_I(old_inode)->i_attrs &= ~ATTR_HIDDEN;
+ if (IS_DIRSYNC(new_dir)) {
+ err = fat_sync_inode(old_inode);
+ if (err)
+ goto error_inode;
+ } else
+ mark_inode_dirty(old_inode);
+
+ if (update_dotdot) {
+ fat_set_start(dotdot_de, MSDOS_I(new_dir)->i_logstart);
+ mark_buffer_dirty_inode(dotdot_bh, old_inode);
+ if (IS_DIRSYNC(new_dir)) {
+ err = sync_dirty_buffer(dotdot_bh);
+ if (err)
+ goto error_dotdot;
+ }
+ drop_nlink(old_dir);
+ if (!new_inode)
+ inc_nlink(new_dir);
+ }
+
+ err = fat_remove_entries(old_dir, &old_sinfo); /* and releases bh */
+ old_sinfo.bh = NULL;
+ if (err)
+ goto error_dotdot;
+ inode_inc_iversion(old_dir);
+ old_dir->i_ctime = old_dir->i_mtime = ts;
+ if (IS_DIRSYNC(old_dir))
+ (void)fat_sync_inode(old_dir);
+ else
+ mark_inode_dirty(old_dir);
+
+ if (new_inode) {
+ drop_nlink(new_inode);
+ if (is_dir)
+ drop_nlink(new_inode);
+ new_inode->i_ctime = ts;
+ }
+out:
+ brelse(sinfo.bh);
+ brelse(dotdot_bh);
+ brelse(old_sinfo.bh);
+ return err;
+
+error_dotdot:
+ /* data cluster is shared, serious corruption */
+ corrupt = 1;
+
+ if (update_dotdot) {
+ fat_set_start(dotdot_de, MSDOS_I(old_dir)->i_logstart);
+ mark_buffer_dirty_inode(dotdot_bh, old_inode);
+ corrupt |= sync_dirty_buffer(dotdot_bh);
+ }
+error_inode:
+ fat_detach(old_inode);
+ fat_attach(old_inode, old_sinfo.i_pos);
+ MSDOS_I(old_inode)->i_attrs = old_attrs;
+ if (new_inode) {
+ fat_attach(new_inode, new_i_pos);
+ if (corrupt)
+ corrupt |= fat_sync_inode(new_inode);
+ } else {
+ /*
+ * If new entry was not sharing the data cluster, it
+ * shouldn't be serious corruption.
+ */
+ int err2 = fat_remove_entries(new_dir, &sinfo);
+ if (corrupt)
+ corrupt |= err2;
+ sinfo.bh = NULL;
+ }
+ if (corrupt < 0) {
+ fat_fs_error(new_dir->i_sb,
+ "%s: Filesystem corrupted (i_pos %lld)",
+ __func__, sinfo.i_pos);
+ }
+ goto out;
+}
+
+/***** Rename, a wrapper for rename_same_dir & rename_diff_dir */
+static int msdos_rename(struct inode *old_dir, struct dentry *old_dentry,
+ struct inode *new_dir, struct dentry *new_dentry,
+ unsigned int flags)
+{
+ struct super_block *sb = old_dir->i_sb;
+ unsigned char old_msdos_name[MSDOS_NAME], new_msdos_name[MSDOS_NAME];
+ int err, is_hid;
+
+ if (flags & ~RENAME_NOREPLACE)
+ return -EINVAL;
+
+ mutex_lock(&MSDOS_SB(sb)->s_lock);
+
+ err = msdos_format_name(old_dentry->d_name.name,
+ old_dentry->d_name.len, old_msdos_name,
+ &MSDOS_SB(old_dir->i_sb)->options);
+ if (err)
+ goto out;
+ err = msdos_format_name(new_dentry->d_name.name,
+ new_dentry->d_name.len, new_msdos_name,
+ &MSDOS_SB(new_dir->i_sb)->options);
+ if (err)
+ goto out;
+
+ is_hid =
+ (new_dentry->d_name.name[0] == '.') && (new_msdos_name[0] != '.');
+
+ err = do_msdos_rename(old_dir, old_msdos_name, old_dentry,
+ new_dir, new_msdos_name, new_dentry, is_hid);
+out:
+ mutex_unlock(&MSDOS_SB(sb)->s_lock);
+ if (!err)
+ err = fat_flush_inodes(sb, old_dir, new_dir);
+ return err;
+}
+
+static const struct inode_operations msdos_dir_inode_operations = {
+ .create = msdos_create,
+ .lookup = msdos_lookup,
+ .unlink = msdos_unlink,
+ .mkdir = msdos_mkdir,
+ .rmdir = msdos_rmdir,
+ .rename = msdos_rename,
+ .setattr = fat_setattr,
+ .getattr = fat_getattr,
+};
+
+static void setup(struct super_block *sb)
+{
+ MSDOS_SB(sb)->dir_ops = &msdos_dir_inode_operations;
+ sb->s_d_op = &msdos_dentry_operations;
+ sb->s_flags |= SB_NOATIME;
+}
+
+static int msdos_fill_super(struct super_block *sb, void *data, int silent)
+{
+ return fat_fill_super(sb, data, silent, 0, setup);
+}
+
+static struct dentry *msdos_mount(struct file_system_type *fs_type,
+ int flags, const char *dev_name,
+ void *data)
+{
+ return mount_bdev(fs_type, flags, dev_name, data, msdos_fill_super);
+}
+
+static struct file_system_type msdos_fs_type = {
+ .owner = THIS_MODULE,
+ .name = "msdos",
+ .mount = msdos_mount,
+ .kill_sb = kill_block_super,
+ .fs_flags = FS_REQUIRES_DEV,
+};
+MODULE_ALIAS_FS("msdos");
+
+static int __init init_msdos_fs(void)
+{
+ return register_filesystem(&msdos_fs_type);
+}
+
+static void __exit exit_msdos_fs(void)
+{
+ unregister_filesystem(&msdos_fs_type);
+}
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Werner Almesberger");
+MODULE_DESCRIPTION("MS-DOS filesystem support");
+
+module_init(init_msdos_fs)
+module_exit(exit_msdos_fs)
diff --git a/fs/fat/namei_vfat.c b/fs/fat/namei_vfat.c
new file mode 100644
index 0000000..82cd1e6
--- /dev/null
+++ b/fs/fat/namei_vfat.c
@@ -0,0 +1,1082 @@
+/*
+ * linux/fs/vfat/namei.c
+ *
+ * Written 1992,1993 by Werner Almesberger
+ *
+ * Windows95/Windows NT compatible extended MSDOS filesystem
+ * by Gordon Chaffee Copyright (C) 1995. Send bug reports for the
+ * VFAT filesystem to <chaffee@cs.berkeley.edu>. Specify
+ * what file operation caused you trouble and if you can duplicate
+ * the problem, send a script that demonstrates it.
+ *
+ * Short name translation 1999, 2001 by Wolfram Pienkoss <wp@bszh.de>
+ *
+ * Support Multibyte characters and cleanup by
+ * OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
+ */
+
+#include <linux/module.h>
+#include <linux/ctype.h>
+#include <linux/slab.h>
+#include <linux/namei.h>
+#include <linux/kernel.h>
+#include <linux/iversion.h>
+#include "fat.h"
+
+static inline unsigned long vfat_d_version(struct dentry *dentry)
+{
+ return (unsigned long) dentry->d_fsdata;
+}
+
+static inline void vfat_d_version_set(struct dentry *dentry,
+ unsigned long version)
+{
+ dentry->d_fsdata = (void *) version;
+}
+
+/*
+ * If new entry was created in the parent, it could create the 8.3
+ * alias (the shortname of logname). So, the parent may have the
+ * negative-dentry which matches the created 8.3 alias.
+ *
+ * If it happened, the negative dentry isn't actually negative
+ * anymore. So, drop it.
+ */
+static int vfat_revalidate_shortname(struct dentry *dentry)
+{
+ int ret = 1;
+ spin_lock(&dentry->d_lock);
+ if (!inode_eq_iversion(d_inode(dentry->d_parent), vfat_d_version(dentry)))
+ ret = 0;
+ spin_unlock(&dentry->d_lock);
+ return ret;
+}
+
+static int vfat_revalidate(struct dentry *dentry, unsigned int flags)
+{
+ if (flags & LOOKUP_RCU)
+ return -ECHILD;
+
+ /* This is not negative dentry. Always valid. */
+ if (d_really_is_positive(dentry))
+ return 1;
+ return vfat_revalidate_shortname(dentry);
+}
+
+static int vfat_revalidate_ci(struct dentry *dentry, unsigned int flags)
+{
+ if (flags & LOOKUP_RCU)
+ return -ECHILD;
+
+ /*
+ * This is not negative dentry. Always valid.
+ *
+ * Note, rename() to existing directory entry will have ->d_inode,
+ * and will use existing name which isn't specified name by user.
+ *
+ * We may be able to drop this positive dentry here. But dropping
+ * positive dentry isn't good idea. So it's unsupported like
+ * rename("filename", "FILENAME") for now.
+ */
+ if (d_really_is_positive(dentry))
+ return 1;
+
+ /*
+ * This may be nfsd (or something), anyway, we can't see the
+ * intent of this. So, since this can be for creation, drop it.
+ */
+ if (!flags)
+ return 0;
+
+ /*
+ * Drop the negative dentry, in order to make sure to use the
+ * case sensitive name which is specified by user if this is
+ * for creation.
+ */
+ if (flags & (LOOKUP_CREATE | LOOKUP_RENAME_TARGET))
+ return 0;
+
+ return vfat_revalidate_shortname(dentry);
+}
+
+/* returns the length of a struct qstr, ignoring trailing dots */
+static unsigned int __vfat_striptail_len(unsigned int len, const char *name)
+{
+ while (len && name[len - 1] == '.')
+ len--;
+ return len;
+}
+
+static unsigned int vfat_striptail_len(const struct qstr *qstr)
+{
+ return __vfat_striptail_len(qstr->len, qstr->name);
+}
+
+/*
+ * Compute the hash for the vfat name corresponding to the dentry.
+ * Note: if the name is invalid, we leave the hash code unchanged so
+ * that the existing dentry can be used. The vfat fs routines will
+ * return ENOENT or EINVAL as appropriate.
+ */
+static int vfat_hash(const struct dentry *dentry, struct qstr *qstr)
+{
+ qstr->hash = full_name_hash(dentry, qstr->name, vfat_striptail_len(qstr));
+ return 0;
+}
+
+/*
+ * Compute the hash for the vfat name corresponding to the dentry.
+ * Note: if the name is invalid, we leave the hash code unchanged so
+ * that the existing dentry can be used. The vfat fs routines will
+ * return ENOENT or EINVAL as appropriate.
+ */
+static int vfat_hashi(const struct dentry *dentry, struct qstr *qstr)
+{
+ struct nls_table *t = MSDOS_SB(dentry->d_sb)->nls_io;
+ const unsigned char *name;
+ unsigned int len;
+ unsigned long hash;
+
+ name = qstr->name;
+ len = vfat_striptail_len(qstr);
+
+ hash = init_name_hash(dentry);
+ while (len--)
+ hash = partial_name_hash(nls_tolower(t, *name++), hash);
+ qstr->hash = end_name_hash(hash);
+
+ return 0;
+}
+
+/*
+ * Case insensitive compare of two vfat names.
+ */
+static int vfat_cmpi(const struct dentry *dentry,
+ unsigned int len, const char *str, const struct qstr *name)
+{
+ struct nls_table *t = MSDOS_SB(dentry->d_sb)->nls_io;
+ unsigned int alen, blen;
+
+ /* A filename cannot end in '.' or we treat it like it has none */
+ alen = vfat_striptail_len(name);
+ blen = __vfat_striptail_len(len, str);
+ if (alen == blen) {
+ if (nls_strnicmp(t, name->name, str, alen) == 0)
+ return 0;
+ }
+ return 1;
+}
+
+/*
+ * Case sensitive compare of two vfat names.
+ */
+static int vfat_cmp(const struct dentry *dentry,
+ unsigned int len, const char *str, const struct qstr *name)
+{
+ unsigned int alen, blen;
+
+ /* A filename cannot end in '.' or we treat it like it has none */
+ alen = vfat_striptail_len(name);
+ blen = __vfat_striptail_len(len, str);
+ if (alen == blen) {
+ if (strncmp(name->name, str, alen) == 0)
+ return 0;
+ }
+ return 1;
+}
+
+static const struct dentry_operations vfat_ci_dentry_ops = {
+ .d_revalidate = vfat_revalidate_ci,
+ .d_hash = vfat_hashi,
+ .d_compare = vfat_cmpi,
+};
+
+static const struct dentry_operations vfat_dentry_ops = {
+ .d_revalidate = vfat_revalidate,
+ .d_hash = vfat_hash,
+ .d_compare = vfat_cmp,
+};
+
+/* Characters that are undesirable in an MS-DOS file name */
+
+static inline wchar_t vfat_bad_char(wchar_t w)
+{
+ return (w < 0x0020)
+ || (w == '*') || (w == '?') || (w == '<') || (w == '>')
+ || (w == '|') || (w == '"') || (w == ':') || (w == '/')
+ || (w == '\\');
+}
+
+static inline wchar_t vfat_replace_char(wchar_t w)
+{
+ return (w == '[') || (w == ']') || (w == ';') || (w == ',')
+ || (w == '+') || (w == '=');
+}
+
+static wchar_t vfat_skip_char(wchar_t w)
+{
+ return (w == '.') || (w == ' ');
+}
+
+static inline int vfat_is_used_badchars(const wchar_t *s, int len)
+{
+ int i;
+
+ for (i = 0; i < len; i++)
+ if (vfat_bad_char(s[i]))
+ return -EINVAL;
+
+ if (s[i - 1] == ' ') /* last character cannot be space */
+ return -EINVAL;
+
+ return 0;
+}
+
+static int vfat_find_form(struct inode *dir, unsigned char *name)
+{
+ struct fat_slot_info sinfo;
+ int err = fat_scan(dir, name, &sinfo);
+ if (err)
+ return -ENOENT;
+ brelse(sinfo.bh);
+ return 0;
+}
+
+/*
+ * 1) Valid characters for the 8.3 format alias are any combination of
+ * letters, uppercase alphabets, digits, any of the
+ * following special characters:
+ * $ % ' ` - @ { } ~ ! # ( ) & _ ^
+ * In this case Longfilename is not stored in disk.
+ *
+ * WinNT's Extension:
+ * File name and extension name is contain uppercase/lowercase
+ * only. And it is expressed by CASE_LOWER_BASE and CASE_LOWER_EXT.
+ *
+ * 2) File name is 8.3 format, but it contain the uppercase and
+ * lowercase char, muliti bytes char, etc. In this case numtail is not
+ * added, but Longfilename is stored.
+ *
+ * 3) When the one except for the above, or the following special
+ * character are contained:
+ * . [ ] ; , + =
+ * numtail is added, and Longfilename must be stored in disk .
+ */
+struct shortname_info {
+ unsigned char lower:1,
+ upper:1,
+ valid:1;
+};
+#define INIT_SHORTNAME_INFO(x) do { \
+ (x)->lower = 1; \
+ (x)->upper = 1; \
+ (x)->valid = 1; \
+} while (0)
+
+static inline int to_shortname_char(struct nls_table *nls,
+ unsigned char *buf, int buf_size,
+ wchar_t *src, struct shortname_info *info)
+{
+ int len;
+
+ if (vfat_skip_char(*src)) {
+ info->valid = 0;
+ return 0;
+ }
+ if (vfat_replace_char(*src)) {
+ info->valid = 0;
+ buf[0] = '_';
+ return 1;
+ }
+
+ len = nls->uni2char(*src, buf, buf_size);
+ if (len <= 0) {
+ info->valid = 0;
+ buf[0] = '_';
+ len = 1;
+ } else if (len == 1) {
+ unsigned char prev = buf[0];
+
+ if (buf[0] >= 0x7F) {
+ info->lower = 0;
+ info->upper = 0;
+ }
+
+ buf[0] = nls_toupper(nls, buf[0]);
+ if (isalpha(buf[0])) {
+ if (buf[0] == prev)
+ info->lower = 0;
+ else
+ info->upper = 0;
+ }
+ } else {
+ info->lower = 0;
+ info->upper = 0;
+ }
+
+ return len;
+}
+
+/*
+ * Given a valid longname, create a unique shortname. Make sure the
+ * shortname does not exist
+ * Returns negative number on error, 0 for a normal
+ * return, and 1 for valid shortname
+ */
+static int vfat_create_shortname(struct inode *dir, struct nls_table *nls,
+ wchar_t *uname, int ulen,
+ unsigned char *name_res, unsigned char *lcase)
+{
+ struct fat_mount_options *opts = &MSDOS_SB(dir->i_sb)->options;
+ wchar_t *ip, *ext_start, *end, *name_start;
+ unsigned char base[9], ext[4], buf[5], *p;
+ unsigned char charbuf[NLS_MAX_CHARSET_SIZE];
+ int chl, chi;
+ int sz = 0, extlen, baselen, i, numtail_baselen, numtail2_baselen;
+ int is_shortname;
+ struct shortname_info base_info, ext_info;
+
+ is_shortname = 1;
+ INIT_SHORTNAME_INFO(&base_info);
+ INIT_SHORTNAME_INFO(&ext_info);
+
+ /* Now, we need to create a shortname from the long name */
+ ext_start = end = &uname[ulen];
+ while (--ext_start >= uname) {
+ if (*ext_start == 0x002E) { /* is `.' */
+ if (ext_start == end - 1) {
+ sz = ulen;
+ ext_start = NULL;
+ }
+ break;
+ }
+ }
+
+ if (ext_start == uname - 1) {
+ sz = ulen;
+ ext_start = NULL;
+ } else if (ext_start) {
+ /*
+ * Names which start with a dot could be just
+ * an extension eg. "...test". In this case Win95
+ * uses the extension as the name and sets no extension.
+ */
+ name_start = &uname[0];
+ while (name_start < ext_start) {
+ if (!vfat_skip_char(*name_start))
+ break;
+ name_start++;
+ }
+ if (name_start != ext_start) {
+ sz = ext_start - uname;
+ ext_start++;
+ } else {
+ sz = ulen;
+ ext_start = NULL;
+ }
+ }
+
+ numtail_baselen = 6;
+ numtail2_baselen = 2;
+ for (baselen = i = 0, p = base, ip = uname; i < sz; i++, ip++) {
+ chl = to_shortname_char(nls, charbuf, sizeof(charbuf),
+ ip, &base_info);
+ if (chl == 0)
+ continue;
+
+ if (baselen < 2 && (baselen + chl) > 2)
+ numtail2_baselen = baselen;
+ if (baselen < 6 && (baselen + chl) > 6)
+ numtail_baselen = baselen;
+ for (chi = 0; chi < chl; chi++) {
+ *p++ = charbuf[chi];
+ baselen++;
+ if (baselen >= 8)
+ break;
+ }
+ if (baselen >= 8) {
+ if ((chi < chl - 1) || (ip + 1) - uname < sz)
+ is_shortname = 0;
+ break;
+ }
+ }
+ if (baselen == 0) {
+ return -EINVAL;
+ }
+
+ extlen = 0;
+ if (ext_start) {
+ for (p = ext, ip = ext_start; extlen < 3 && ip < end; ip++) {
+ chl = to_shortname_char(nls, charbuf, sizeof(charbuf),
+ ip, &ext_info);
+ if (chl == 0)
+ continue;
+
+ if ((extlen + chl) > 3) {
+ is_shortname = 0;
+ break;
+ }
+ for (chi = 0; chi < chl; chi++) {
+ *p++ = charbuf[chi];
+ extlen++;
+ }
+ if (extlen >= 3) {
+ if (ip + 1 != end)
+ is_shortname = 0;
+ break;
+ }
+ }
+ }
+ ext[extlen] = '\0';
+ base[baselen] = '\0';
+
+ /* Yes, it can happen. ".\xe5" would do it. */
+ if (base[0] == DELETED_FLAG)
+ base[0] = 0x05;
+
+ /* OK, at this point we know that base is not longer than 8 symbols,
+ * ext is not longer than 3, base is nonempty, both don't contain
+ * any bad symbols (lowercase transformed to uppercase).
+ */
+
+ memset(name_res, ' ', MSDOS_NAME);
+ memcpy(name_res, base, baselen);
+ memcpy(name_res + 8, ext, extlen);
+ *lcase = 0;
+ if (is_shortname && base_info.valid && ext_info.valid) {
+ if (vfat_find_form(dir, name_res) == 0)
+ return -EEXIST;
+
+ if (opts->shortname & VFAT_SFN_CREATE_WIN95) {
+ return (base_info.upper && ext_info.upper);
+ } else if (opts->shortname & VFAT_SFN_CREATE_WINNT) {
+ if ((base_info.upper || base_info.lower) &&
+ (ext_info.upper || ext_info.lower)) {
+ if (!base_info.upper && base_info.lower)
+ *lcase |= CASE_LOWER_BASE;
+ if (!ext_info.upper && ext_info.lower)
+ *lcase |= CASE_LOWER_EXT;
+ return 1;
+ }
+ return 0;
+ } else {
+ BUG();
+ }
+ }
+
+ if (opts->numtail == 0)
+ if (vfat_find_form(dir, name_res) < 0)
+ return 0;
+
+ /*
+ * Try to find a unique extension. This used to
+ * iterate through all possibilities sequentially,
+ * but that gave extremely bad performance. Windows
+ * only tries a few cases before using random
+ * values for part of the base.
+ */
+
+ if (baselen > 6) {
+ baselen = numtail_baselen;
+ name_res[7] = ' ';
+ }
+ name_res[baselen] = '~';
+ for (i = 1; i < 10; i++) {
+ name_res[baselen + 1] = i + '0';
+ if (vfat_find_form(dir, name_res) < 0)
+ return 0;
+ }
+
+ i = jiffies;
+ sz = (jiffies >> 16) & 0x7;
+ if (baselen > 2) {
+ baselen = numtail2_baselen;
+ name_res[7] = ' ';
+ }
+ name_res[baselen + 4] = '~';
+ name_res[baselen + 5] = '1' + sz;
+ while (1) {
+ snprintf(buf, sizeof(buf), "%04X", i & 0xffff);
+ memcpy(&name_res[baselen], buf, 4);
+ if (vfat_find_form(dir, name_res) < 0)
+ break;
+ i -= 11;
+ }
+ return 0;
+}
+
+/* Translate a string, including coded sequences into Unicode */
+static int
+xlate_to_uni(const unsigned char *name, int len, unsigned char *outname,
+ int *longlen, int *outlen, int escape, int utf8,
+ struct nls_table *nls)
+{
+ const unsigned char *ip;
+ unsigned char *op;
+ int i, fill;
+ int charlen;
+
+ if (utf8) {
+ *outlen = utf8s_to_utf16s(name, len, UTF16_HOST_ENDIAN,
+ (wchar_t *) outname, FAT_LFN_LEN + 2);
+ if (*outlen < 0)
+ return *outlen;
+ else if (*outlen > FAT_LFN_LEN)
+ return -ENAMETOOLONG;
+
+ op = &outname[*outlen * sizeof(wchar_t)];
+ } else {
+ for (i = 0, ip = name, op = outname, *outlen = 0;
+ i < len && *outlen < FAT_LFN_LEN;
+ *outlen += 1) {
+ if (escape && (*ip == ':')) {
+ u8 uc[2];
+
+ if (i > len - 5)
+ return -EINVAL;
+
+ if (hex2bin(uc, ip + 1, 2) < 0)
+ return -EINVAL;
+
+ *(wchar_t *)op = uc[0] << 8 | uc[1];
+
+ op += 2;
+ ip += 5;
+ i += 5;
+ } else {
+ charlen = nls->char2uni(ip, len - i,
+ (wchar_t *)op);
+ if (charlen < 0)
+ return -EINVAL;
+ ip += charlen;
+ i += charlen;
+ op += 2;
+ }
+ }
+ if (i < len)
+ return -ENAMETOOLONG;
+ }
+
+ *longlen = *outlen;
+ if (*outlen % 13) {
+ *op++ = 0;
+ *op++ = 0;
+ *outlen += 1;
+ if (*outlen % 13) {
+ fill = 13 - (*outlen % 13);
+ for (i = 0; i < fill; i++) {
+ *op++ = 0xff;
+ *op++ = 0xff;
+ }
+ *outlen += fill;
+ }
+ }
+
+ return 0;
+}
+
+static int vfat_build_slots(struct inode *dir, const unsigned char *name,
+ int len, int is_dir, int cluster,
+ struct timespec64 *ts,
+ struct msdos_dir_slot *slots, int *nr_slots)
+{
+ struct msdos_sb_info *sbi = MSDOS_SB(dir->i_sb);
+ struct fat_mount_options *opts = &sbi->options;
+ struct msdos_dir_slot *ps;
+ struct msdos_dir_entry *de;
+ unsigned char cksum, lcase;
+ unsigned char msdos_name[MSDOS_NAME];
+ wchar_t *uname;
+ __le16 time, date;
+ u8 time_cs;
+ int err, ulen, usize, i;
+ loff_t offset;
+
+ *nr_slots = 0;
+
+ uname = __getname();
+ if (!uname)
+ return -ENOMEM;
+
+ err = xlate_to_uni(name, len, (unsigned char *)uname, &ulen, &usize,
+ opts->unicode_xlate, opts->utf8, sbi->nls_io);
+ if (err)
+ goto out_free;
+
+ err = vfat_is_used_badchars(uname, ulen);
+ if (err)
+ goto out_free;
+
+ err = vfat_create_shortname(dir, sbi->nls_disk, uname, ulen,
+ msdos_name, &lcase);
+ if (err < 0)
+ goto out_free;
+ else if (err == 1) {
+ de = (struct msdos_dir_entry *)slots;
+ err = 0;
+ goto shortname;
+ }
+
+ /* build the entry of long file name */
+ cksum = fat_checksum(msdos_name);
+
+ *nr_slots = usize / 13;
+ for (ps = slots, i = *nr_slots; i > 0; i--, ps++) {
+ ps->id = i;
+ ps->attr = ATTR_EXT;
+ ps->reserved = 0;
+ ps->alias_checksum = cksum;
+ ps->start = 0;
+ offset = (i - 1) * 13;
+ fatwchar_to16(ps->name0_4, uname + offset, 5);
+ fatwchar_to16(ps->name5_10, uname + offset + 5, 6);
+ fatwchar_to16(ps->name11_12, uname + offset + 11, 2);
+ }
+ slots[0].id |= 0x40;
+ de = (struct msdos_dir_entry *)ps;
+
+shortname:
+ /* build the entry of 8.3 alias name */
+ (*nr_slots)++;
+ memcpy(de->name, msdos_name, MSDOS_NAME);
+ de->attr = is_dir ? ATTR_DIR : ATTR_ARCH;
+ de->lcase = lcase;
+ fat_time_unix2fat(sbi, ts, &time, &date, &time_cs);
+ de->time = de->ctime = time;
+ de->date = de->cdate = de->adate = date;
+ de->ctime_cs = time_cs;
+ fat_set_start(de, cluster);
+ de->size = 0;
+out_free:
+ __putname(uname);
+ return err;
+}
+
+static int vfat_add_entry(struct inode *dir, const struct qstr *qname,
+ int is_dir, int cluster, struct timespec64 *ts,
+ struct fat_slot_info *sinfo)
+{
+ struct msdos_dir_slot *slots;
+ unsigned int len;
+ int err, nr_slots;
+
+ len = vfat_striptail_len(qname);
+ if (len == 0)
+ return -ENOENT;
+
+ slots = kmalloc_array(MSDOS_SLOTS, sizeof(*slots), GFP_NOFS);
+ if (slots == NULL)
+ return -ENOMEM;
+
+ err = vfat_build_slots(dir, qname->name, len, is_dir, cluster, ts,
+ slots, &nr_slots);
+ if (err)
+ goto cleanup;
+
+ err = fat_add_entries(dir, slots, nr_slots, sinfo);
+ if (err)
+ goto cleanup;
+
+ /* update timestamp */
+ dir->i_ctime = dir->i_mtime = dir->i_atime = *ts;
+ if (IS_DIRSYNC(dir))
+ (void)fat_sync_inode(dir);
+ else
+ mark_inode_dirty(dir);
+cleanup:
+ kfree(slots);
+ return err;
+}
+
+static int vfat_find(struct inode *dir, const struct qstr *qname,
+ struct fat_slot_info *sinfo)
+{
+ unsigned int len = vfat_striptail_len(qname);
+ if (len == 0)
+ return -ENOENT;
+ return fat_search_long(dir, qname->name, len, sinfo);
+}
+
+static struct dentry *vfat_lookup(struct inode *dir, struct dentry *dentry,
+ unsigned int flags)
+{
+ struct super_block *sb = dir->i_sb;
+ struct fat_slot_info sinfo;
+ struct inode *inode;
+ struct dentry *alias;
+ int err;
+
+ mutex_lock(&MSDOS_SB(sb)->s_lock);
+
+ err = vfat_find(dir, &dentry->d_name, &sinfo);
+ if (err) {
+ if (err == -ENOENT) {
+ inode = NULL;
+ goto out;
+ }
+ goto error;
+ }
+
+ inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
+ brelse(sinfo.bh);
+ if (IS_ERR(inode)) {
+ err = PTR_ERR(inode);
+ goto error;
+ }
+
+ alias = d_find_alias(inode);
+ /*
+ * Checking "alias->d_parent == dentry->d_parent" to make sure
+ * FS is not corrupted (especially double linked dir).
+ */
+ if (alias && alias->d_parent == dentry->d_parent) {
+ /*
+ * This inode has non anonymous-DCACHE_DISCONNECTED
+ * dentry. This means, the user did ->lookup() by an
+ * another name (longname vs 8.3 alias of it) in past.
+ *
+ * Switch to new one for reason of locality if possible.
+ */
+ if (!S_ISDIR(inode->i_mode))
+ d_move(alias, dentry);
+ iput(inode);
+ mutex_unlock(&MSDOS_SB(sb)->s_lock);
+ return alias;
+ } else
+ dput(alias);
+
+out:
+ mutex_unlock(&MSDOS_SB(sb)->s_lock);
+ if (!inode)
+ vfat_d_version_set(dentry, inode_query_iversion(dir));
+ return d_splice_alias(inode, dentry);
+error:
+ mutex_unlock(&MSDOS_SB(sb)->s_lock);
+ return ERR_PTR(err);
+}
+
+static int vfat_create(struct inode *dir, struct dentry *dentry, umode_t mode,
+ bool excl)
+{
+ struct super_block *sb = dir->i_sb;
+ struct inode *inode;
+ struct fat_slot_info sinfo;
+ struct timespec64 ts;
+ int err;
+
+ mutex_lock(&MSDOS_SB(sb)->s_lock);
+
+ ts = current_time(dir);
+ err = vfat_add_entry(dir, &dentry->d_name, 0, 0, &ts, &sinfo);
+ if (err)
+ goto out;
+ inode_inc_iversion(dir);
+
+ inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
+ brelse(sinfo.bh);
+ if (IS_ERR(inode)) {
+ err = PTR_ERR(inode);
+ goto out;
+ }
+ inode_inc_iversion(inode);
+ inode->i_mtime = inode->i_atime = inode->i_ctime = ts;
+ /* timestamp is already written, so mark_inode_dirty() is unneeded. */
+
+ d_instantiate(dentry, inode);
+out:
+ mutex_unlock(&MSDOS_SB(sb)->s_lock);
+ return err;
+}
+
+static int vfat_rmdir(struct inode *dir, struct dentry *dentry)
+{
+ struct inode *inode = d_inode(dentry);
+ struct super_block *sb = dir->i_sb;
+ struct fat_slot_info sinfo;
+ int err;
+
+ mutex_lock(&MSDOS_SB(sb)->s_lock);
+
+ err = fat_dir_empty(inode);
+ if (err)
+ goto out;
+ err = vfat_find(dir, &dentry->d_name, &sinfo);
+ if (err)
+ goto out;
+
+ err = fat_remove_entries(dir, &sinfo); /* and releases bh */
+ if (err)
+ goto out;
+ drop_nlink(dir);
+
+ clear_nlink(inode);
+ inode->i_mtime = inode->i_atime = current_time(inode);
+ fat_detach(inode);
+ vfat_d_version_set(dentry, inode_query_iversion(dir));
+out:
+ mutex_unlock(&MSDOS_SB(sb)->s_lock);
+
+ return err;
+}
+
+static int vfat_unlink(struct inode *dir, struct dentry *dentry)
+{
+ struct inode *inode = d_inode(dentry);
+ struct super_block *sb = dir->i_sb;
+ struct fat_slot_info sinfo;
+ int err;
+
+ mutex_lock(&MSDOS_SB(sb)->s_lock);
+
+ err = vfat_find(dir, &dentry->d_name, &sinfo);
+ if (err)
+ goto out;
+
+ err = fat_remove_entries(dir, &sinfo); /* and releases bh */
+ if (err)
+ goto out;
+ clear_nlink(inode);
+ inode->i_mtime = inode->i_atime = current_time(inode);
+ fat_detach(inode);
+ vfat_d_version_set(dentry, inode_query_iversion(dir));
+out:
+ mutex_unlock(&MSDOS_SB(sb)->s_lock);
+
+ return err;
+}
+
+static int vfat_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
+{
+ struct super_block *sb = dir->i_sb;
+ struct inode *inode;
+ struct fat_slot_info sinfo;
+ struct timespec64 ts;
+ int err, cluster;
+
+ mutex_lock(&MSDOS_SB(sb)->s_lock);
+
+ ts = current_time(dir);
+ cluster = fat_alloc_new_dir(dir, &ts);
+ if (cluster < 0) {
+ err = cluster;
+ goto out;
+ }
+ err = vfat_add_entry(dir, &dentry->d_name, 1, cluster, &ts, &sinfo);
+ if (err)
+ goto out_free;
+ inode_inc_iversion(dir);
+ inc_nlink(dir);
+
+ inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
+ brelse(sinfo.bh);
+ if (IS_ERR(inode)) {
+ err = PTR_ERR(inode);
+ /* the directory was completed, just return a error */
+ goto out;
+ }
+ inode_inc_iversion(inode);
+ set_nlink(inode, 2);
+ inode->i_mtime = inode->i_atime = inode->i_ctime = ts;
+ /* timestamp is already written, so mark_inode_dirty() is unneeded. */
+
+ d_instantiate(dentry, inode);
+
+ mutex_unlock(&MSDOS_SB(sb)->s_lock);
+ return 0;
+
+out_free:
+ fat_free_clusters(dir, cluster);
+out:
+ mutex_unlock(&MSDOS_SB(sb)->s_lock);
+ return err;
+}
+
+static int vfat_rename(struct inode *old_dir, struct dentry *old_dentry,
+ struct inode *new_dir, struct dentry *new_dentry,
+ unsigned int flags)
+{
+ struct buffer_head *dotdot_bh;
+ struct msdos_dir_entry *dotdot_de;
+ struct inode *old_inode, *new_inode;
+ struct fat_slot_info old_sinfo, sinfo;
+ struct timespec64 ts;
+ loff_t new_i_pos;
+ int err, is_dir, update_dotdot, corrupt = 0;
+ struct super_block *sb = old_dir->i_sb;
+
+ if (flags & ~RENAME_NOREPLACE)
+ return -EINVAL;
+
+ old_sinfo.bh = sinfo.bh = dotdot_bh = NULL;
+ old_inode = d_inode(old_dentry);
+ new_inode = d_inode(new_dentry);
+ mutex_lock(&MSDOS_SB(sb)->s_lock);
+ err = vfat_find(old_dir, &old_dentry->d_name, &old_sinfo);
+ if (err)
+ goto out;
+
+ is_dir = S_ISDIR(old_inode->i_mode);
+ update_dotdot = (is_dir && old_dir != new_dir);
+ if (update_dotdot) {
+ if (fat_get_dotdot_entry(old_inode, &dotdot_bh, &dotdot_de)) {
+ err = -EIO;
+ goto out;
+ }
+ }
+
+ ts = current_time(old_dir);
+ if (new_inode) {
+ if (is_dir) {
+ err = fat_dir_empty(new_inode);
+ if (err)
+ goto out;
+ }
+ new_i_pos = MSDOS_I(new_inode)->i_pos;
+ fat_detach(new_inode);
+ } else {
+ err = vfat_add_entry(new_dir, &new_dentry->d_name, is_dir, 0,
+ &ts, &sinfo);
+ if (err)
+ goto out;
+ new_i_pos = sinfo.i_pos;
+ }
+ inode_inc_iversion(new_dir);
+
+ fat_detach(old_inode);
+ fat_attach(old_inode, new_i_pos);
+ if (IS_DIRSYNC(new_dir)) {
+ err = fat_sync_inode(old_inode);
+ if (err)
+ goto error_inode;
+ } else
+ mark_inode_dirty(old_inode);
+
+ if (update_dotdot) {
+ fat_set_start(dotdot_de, MSDOS_I(new_dir)->i_logstart);
+ mark_buffer_dirty_inode(dotdot_bh, old_inode);
+ if (IS_DIRSYNC(new_dir)) {
+ err = sync_dirty_buffer(dotdot_bh);
+ if (err)
+ goto error_dotdot;
+ }
+ drop_nlink(old_dir);
+ if (!new_inode)
+ inc_nlink(new_dir);
+ }
+
+ err = fat_remove_entries(old_dir, &old_sinfo); /* and releases bh */
+ old_sinfo.bh = NULL;
+ if (err)
+ goto error_dotdot;
+ inode_inc_iversion(old_dir);
+ old_dir->i_ctime = old_dir->i_mtime = ts;
+ if (IS_DIRSYNC(old_dir))
+ (void)fat_sync_inode(old_dir);
+ else
+ mark_inode_dirty(old_dir);
+
+ if (new_inode) {
+ drop_nlink(new_inode);
+ if (is_dir)
+ drop_nlink(new_inode);
+ new_inode->i_ctime = ts;
+ }
+out:
+ brelse(sinfo.bh);
+ brelse(dotdot_bh);
+ brelse(old_sinfo.bh);
+ mutex_unlock(&MSDOS_SB(sb)->s_lock);
+
+ return err;
+
+error_dotdot:
+ /* data cluster is shared, serious corruption */
+ corrupt = 1;
+
+ if (update_dotdot) {
+ fat_set_start(dotdot_de, MSDOS_I(old_dir)->i_logstart);
+ mark_buffer_dirty_inode(dotdot_bh, old_inode);
+ corrupt |= sync_dirty_buffer(dotdot_bh);
+ }
+error_inode:
+ fat_detach(old_inode);
+ fat_attach(old_inode, old_sinfo.i_pos);
+ if (new_inode) {
+ fat_attach(new_inode, new_i_pos);
+ if (corrupt)
+ corrupt |= fat_sync_inode(new_inode);
+ } else {
+ /*
+ * If new entry was not sharing the data cluster, it
+ * shouldn't be serious corruption.
+ */
+ int err2 = fat_remove_entries(new_dir, &sinfo);
+ if (corrupt)
+ corrupt |= err2;
+ sinfo.bh = NULL;
+ }
+ if (corrupt < 0) {
+ fat_fs_error(new_dir->i_sb,
+ "%s: Filesystem corrupted (i_pos %lld)",
+ __func__, sinfo.i_pos);
+ }
+ goto out;
+}
+
+static const struct inode_operations vfat_dir_inode_operations = {
+ .create = vfat_create,
+ .lookup = vfat_lookup,
+ .unlink = vfat_unlink,
+ .mkdir = vfat_mkdir,
+ .rmdir = vfat_rmdir,
+ .rename = vfat_rename,
+ .setattr = fat_setattr,
+ .getattr = fat_getattr,
+};
+
+static void setup(struct super_block *sb)
+{
+ MSDOS_SB(sb)->dir_ops = &vfat_dir_inode_operations;
+ if (MSDOS_SB(sb)->options.name_check != 's')
+ sb->s_d_op = &vfat_ci_dentry_ops;
+ else
+ sb->s_d_op = &vfat_dentry_ops;
+}
+
+static int vfat_fill_super(struct super_block *sb, void *data, int silent)
+{
+ return fat_fill_super(sb, data, silent, 1, setup);
+}
+
+static struct dentry *vfat_mount(struct file_system_type *fs_type,
+ int flags, const char *dev_name,
+ void *data)
+{
+ return mount_bdev(fs_type, flags, dev_name, data, vfat_fill_super);
+}
+
+static struct file_system_type vfat_fs_type = {
+ .owner = THIS_MODULE,
+ .name = "vfat",
+ .mount = vfat_mount,
+ .kill_sb = kill_block_super,
+ .fs_flags = FS_REQUIRES_DEV,
+};
+MODULE_ALIAS_FS("vfat");
+
+static int __init init_vfat_fs(void)
+{
+ return register_filesystem(&vfat_fs_type);
+}
+
+static void __exit exit_vfat_fs(void)
+{
+ unregister_filesystem(&vfat_fs_type);
+}
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("VFAT filesystem support");
+MODULE_AUTHOR("Gordon Chaffee");
+
+module_init(init_vfat_fs)
+module_exit(exit_vfat_fs)
diff --git a/fs/fat/nfs.c b/fs/fat/nfs.c
new file mode 100644
index 0000000..eb19265
--- /dev/null
+++ b/fs/fat/nfs.c
@@ -0,0 +1,301 @@
+/* fs/fat/nfs.c
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#include <linux/exportfs.h>
+#include "fat.h"
+
+struct fat_fid {
+ u32 i_gen;
+ u32 i_pos_low;
+ u16 i_pos_hi;
+ u16 parent_i_pos_hi;
+ u32 parent_i_pos_low;
+ u32 parent_i_gen;
+};
+
+#define FAT_FID_SIZE_WITHOUT_PARENT 3
+#define FAT_FID_SIZE_WITH_PARENT (sizeof(struct fat_fid)/sizeof(u32))
+
+/**
+ * Look up a directory inode given its starting cluster.
+ */
+static struct inode *fat_dget(struct super_block *sb, int i_logstart)
+{
+ struct msdos_sb_info *sbi = MSDOS_SB(sb);
+ struct hlist_head *head;
+ struct msdos_inode_info *i;
+ struct inode *inode = NULL;
+
+ head = sbi->dir_hashtable + fat_dir_hash(i_logstart);
+ spin_lock(&sbi->dir_hash_lock);
+ hlist_for_each_entry(i, head, i_dir_hash) {
+ BUG_ON(i->vfs_inode.i_sb != sb);
+ if (i->i_logstart != i_logstart)
+ continue;
+ inode = igrab(&i->vfs_inode);
+ if (inode)
+ break;
+ }
+ spin_unlock(&sbi->dir_hash_lock);
+ return inode;
+}
+
+static struct inode *fat_ilookup(struct super_block *sb, u64 ino, loff_t i_pos)
+{
+ if (MSDOS_SB(sb)->options.nfs == FAT_NFS_NOSTALE_RO)
+ return fat_iget(sb, i_pos);
+
+ else {
+ if ((ino < MSDOS_ROOT_INO) || (ino == MSDOS_FSINFO_INO))
+ return NULL;
+ return ilookup(sb, ino);
+ }
+}
+
+static struct inode *__fat_nfs_get_inode(struct super_block *sb,
+ u64 ino, u32 generation, loff_t i_pos)
+{
+ struct inode *inode = fat_ilookup(sb, ino, i_pos);
+
+ if (inode && generation && (inode->i_generation != generation)) {
+ iput(inode);
+ inode = NULL;
+ }
+ if (inode == NULL && MSDOS_SB(sb)->options.nfs == FAT_NFS_NOSTALE_RO) {
+ struct buffer_head *bh = NULL;
+ struct msdos_dir_entry *de ;
+ sector_t blocknr;
+ int offset;
+ fat_get_blknr_offset(MSDOS_SB(sb), i_pos, &blocknr, &offset);
+ bh = sb_bread(sb, blocknr);
+ if (!bh) {
+ fat_msg(sb, KERN_ERR,
+ "unable to read block(%llu) for building NFS inode",
+ (llu)blocknr);
+ return inode;
+ }
+ de = (struct msdos_dir_entry *)bh->b_data;
+ /* If a file is deleted on server and client is not updated
+ * yet, we must not build the inode upon a lookup call.
+ */
+ if (IS_FREE(de[offset].name))
+ inode = NULL;
+ else
+ inode = fat_build_inode(sb, &de[offset], i_pos);
+ brelse(bh);
+ }
+
+ return inode;
+}
+
+static struct inode *fat_nfs_get_inode(struct super_block *sb,
+ u64 ino, u32 generation)
+{
+
+ return __fat_nfs_get_inode(sb, ino, generation, 0);
+}
+
+static int
+fat_encode_fh_nostale(struct inode *inode, __u32 *fh, int *lenp,
+ struct inode *parent)
+{
+ int len = *lenp;
+ struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
+ struct fat_fid *fid = (struct fat_fid *) fh;
+ loff_t i_pos;
+ int type = FILEID_FAT_WITHOUT_PARENT;
+
+ if (parent) {
+ if (len < FAT_FID_SIZE_WITH_PARENT) {
+ *lenp = FAT_FID_SIZE_WITH_PARENT;
+ return FILEID_INVALID;
+ }
+ } else {
+ if (len < FAT_FID_SIZE_WITHOUT_PARENT) {
+ *lenp = FAT_FID_SIZE_WITHOUT_PARENT;
+ return FILEID_INVALID;
+ }
+ }
+
+ i_pos = fat_i_pos_read(sbi, inode);
+ *lenp = FAT_FID_SIZE_WITHOUT_PARENT;
+ fid->i_gen = inode->i_generation;
+ fid->i_pos_low = i_pos & 0xFFFFFFFF;
+ fid->i_pos_hi = (i_pos >> 32) & 0xFFFF;
+ if (parent) {
+ i_pos = fat_i_pos_read(sbi, parent);
+ fid->parent_i_pos_hi = (i_pos >> 32) & 0xFFFF;
+ fid->parent_i_pos_low = i_pos & 0xFFFFFFFF;
+ fid->parent_i_gen = parent->i_generation;
+ type = FILEID_FAT_WITH_PARENT;
+ *lenp = FAT_FID_SIZE_WITH_PARENT;
+ }
+
+ return type;
+}
+
+/**
+ * Map a NFS file handle to a corresponding dentry.
+ * The dentry may or may not be connected to the filesystem root.
+ */
+static struct dentry *fat_fh_to_dentry(struct super_block *sb, struct fid *fid,
+ int fh_len, int fh_type)
+{
+ return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
+ fat_nfs_get_inode);
+}
+
+static struct dentry *fat_fh_to_dentry_nostale(struct super_block *sb,
+ struct fid *fh, int fh_len,
+ int fh_type)
+{
+ struct inode *inode = NULL;
+ struct fat_fid *fid = (struct fat_fid *)fh;
+ loff_t i_pos;
+
+ switch (fh_type) {
+ case FILEID_FAT_WITHOUT_PARENT:
+ if (fh_len < FAT_FID_SIZE_WITHOUT_PARENT)
+ return NULL;
+ break;
+ case FILEID_FAT_WITH_PARENT:
+ if (fh_len < FAT_FID_SIZE_WITH_PARENT)
+ return NULL;
+ break;
+ default:
+ return NULL;
+ }
+ i_pos = fid->i_pos_hi;
+ i_pos = (i_pos << 32) | (fid->i_pos_low);
+ inode = __fat_nfs_get_inode(sb, 0, fid->i_gen, i_pos);
+
+ return d_obtain_alias(inode);
+}
+
+/*
+ * Find the parent for a file specified by NFS handle.
+ * This requires that the handle contain the i_ino of the parent.
+ */
+static struct dentry *fat_fh_to_parent(struct super_block *sb, struct fid *fid,
+ int fh_len, int fh_type)
+{
+ return generic_fh_to_parent(sb, fid, fh_len, fh_type,
+ fat_nfs_get_inode);
+}
+
+static struct dentry *fat_fh_to_parent_nostale(struct super_block *sb,
+ struct fid *fh, int fh_len,
+ int fh_type)
+{
+ struct inode *inode = NULL;
+ struct fat_fid *fid = (struct fat_fid *)fh;
+ loff_t i_pos;
+
+ if (fh_len < FAT_FID_SIZE_WITH_PARENT)
+ return NULL;
+
+ switch (fh_type) {
+ case FILEID_FAT_WITH_PARENT:
+ i_pos = fid->parent_i_pos_hi;
+ i_pos = (i_pos << 32) | (fid->parent_i_pos_low);
+ inode = __fat_nfs_get_inode(sb, 0, fid->parent_i_gen, i_pos);
+ break;
+ }
+
+ return d_obtain_alias(inode);
+}
+
+/*
+ * Rebuild the parent for a directory that is not connected
+ * to the filesystem root
+ */
+static
+struct inode *fat_rebuild_parent(struct super_block *sb, int parent_logstart)
+{
+ int search_clus, clus_to_match;
+ struct msdos_dir_entry *de;
+ struct inode *parent = NULL;
+ struct inode *dummy_grand_parent = NULL;
+ struct fat_slot_info sinfo;
+ struct msdos_sb_info *sbi = MSDOS_SB(sb);
+ sector_t blknr = fat_clus_to_blknr(sbi, parent_logstart);
+ struct buffer_head *parent_bh = sb_bread(sb, blknr);
+ if (!parent_bh) {
+ fat_msg(sb, KERN_ERR,
+ "unable to read cluster of parent directory");
+ return NULL;
+ }
+
+ de = (struct msdos_dir_entry *) parent_bh->b_data;
+ clus_to_match = fat_get_start(sbi, &de[0]);
+ search_clus = fat_get_start(sbi, &de[1]);
+
+ dummy_grand_parent = fat_dget(sb, search_clus);
+ if (!dummy_grand_parent) {
+ dummy_grand_parent = new_inode(sb);
+ if (!dummy_grand_parent) {
+ brelse(parent_bh);
+ return parent;
+ }
+
+ dummy_grand_parent->i_ino = iunique(sb, MSDOS_ROOT_INO);
+ fat_fill_inode(dummy_grand_parent, &de[1]);
+ MSDOS_I(dummy_grand_parent)->i_pos = -1;
+ }
+
+ if (!fat_scan_logstart(dummy_grand_parent, clus_to_match, &sinfo))
+ parent = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
+
+ brelse(parent_bh);
+ iput(dummy_grand_parent);
+
+ return parent;
+}
+
+/*
+ * Find the parent for a directory that is not currently connected to
+ * the filesystem root.
+ *
+ * On entry, the caller holds d_inode(child_dir)->i_mutex.
+ */
+static struct dentry *fat_get_parent(struct dentry *child_dir)
+{
+ struct super_block *sb = child_dir->d_sb;
+ struct buffer_head *bh = NULL;
+ struct msdos_dir_entry *de;
+ struct inode *parent_inode = NULL;
+ struct msdos_sb_info *sbi = MSDOS_SB(sb);
+
+ if (!fat_get_dotdot_entry(d_inode(child_dir), &bh, &de)) {
+ int parent_logstart = fat_get_start(sbi, de);
+ parent_inode = fat_dget(sb, parent_logstart);
+ if (!parent_inode && sbi->options.nfs == FAT_NFS_NOSTALE_RO)
+ parent_inode = fat_rebuild_parent(sb, parent_logstart);
+ }
+ brelse(bh);
+
+ return d_obtain_alias(parent_inode);
+}
+
+const struct export_operations fat_export_ops = {
+ .fh_to_dentry = fat_fh_to_dentry,
+ .fh_to_parent = fat_fh_to_parent,
+ .get_parent = fat_get_parent,
+};
+
+const struct export_operations fat_export_ops_nostale = {
+ .encode_fh = fat_encode_fh_nostale,
+ .fh_to_dentry = fat_fh_to_dentry_nostale,
+ .fh_to_parent = fat_fh_to_parent_nostale,
+ .get_parent = fat_get_parent,
+};