v4.19.13 snapshot.
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
new file mode 100644
index 0000000..8ad1458
--- /dev/null
+++ b/fs/btrfs/super.c
@@ -0,0 +1,2513 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2007 Oracle. All rights reserved.
+ */
+
+#include <linux/blkdev.h>
+#include <linux/module.h>
+#include <linux/fs.h>
+#include <linux/pagemap.h>
+#include <linux/highmem.h>
+#include <linux/time.h>
+#include <linux/init.h>
+#include <linux/seq_file.h>
+#include <linux/string.h>
+#include <linux/backing-dev.h>
+#include <linux/mount.h>
+#include <linux/writeback.h>
+#include <linux/statfs.h>
+#include <linux/compat.h>
+#include <linux/parser.h>
+#include <linux/ctype.h>
+#include <linux/namei.h>
+#include <linux/miscdevice.h>
+#include <linux/magic.h>
+#include <linux/slab.h>
+#include <linux/cleancache.h>
+#include <linux/ratelimit.h>
+#include <linux/crc32c.h>
+#include <linux/btrfs.h>
+#include "delayed-inode.h"
+#include "ctree.h"
+#include "disk-io.h"
+#include "transaction.h"
+#include "btrfs_inode.h"
+#include "print-tree.h"
+#include "props.h"
+#include "xattr.h"
+#include "volumes.h"
+#include "export.h"
+#include "compression.h"
+#include "rcu-string.h"
+#include "dev-replace.h"
+#include "free-space-cache.h"
+#include "backref.h"
+#include "tests/btrfs-tests.h"
+
+#include "qgroup.h"
+#define CREATE_TRACE_POINTS
+#include <trace/events/btrfs.h>
+
+static const struct super_operations btrfs_super_ops;
+
+/*
+ * Types for mounting the default subvolume and a subvolume explicitly
+ * requested by subvol=/path. That way the callchain is straightforward and we
+ * don't have to play tricks with the mount options and recursive calls to
+ * btrfs_mount.
+ *
+ * The new btrfs_root_fs_type also servers as a tag for the bdev_holder.
+ */
+static struct file_system_type btrfs_fs_type;
+static struct file_system_type btrfs_root_fs_type;
+
+static int btrfs_remount(struct super_block *sb, int *flags, char *data);
+
+const char *btrfs_decode_error(int errno)
+{
+ char *errstr = "unknown";
+
+ switch (errno) {
+ case -EIO:
+ errstr = "IO failure";
+ break;
+ case -ENOMEM:
+ errstr = "Out of memory";
+ break;
+ case -EROFS:
+ errstr = "Readonly filesystem";
+ break;
+ case -EEXIST:
+ errstr = "Object already exists";
+ break;
+ case -ENOSPC:
+ errstr = "No space left";
+ break;
+ case -ENOENT:
+ errstr = "No such entry";
+ break;
+ }
+
+ return errstr;
+}
+
+/*
+ * __btrfs_handle_fs_error decodes expected errors from the caller and
+ * invokes the approciate error response.
+ */
+__cold
+void __btrfs_handle_fs_error(struct btrfs_fs_info *fs_info, const char *function,
+ unsigned int line, int errno, const char *fmt, ...)
+{
+ struct super_block *sb = fs_info->sb;
+#ifdef CONFIG_PRINTK
+ const char *errstr;
+#endif
+
+ /*
+ * Special case: if the error is EROFS, and we're already
+ * under SB_RDONLY, then it is safe here.
+ */
+ if (errno == -EROFS && sb_rdonly(sb))
+ return;
+
+#ifdef CONFIG_PRINTK
+ errstr = btrfs_decode_error(errno);
+ if (fmt) {
+ struct va_format vaf;
+ va_list args;
+
+ va_start(args, fmt);
+ vaf.fmt = fmt;
+ vaf.va = &args;
+
+ pr_crit("BTRFS: error (device %s) in %s:%d: errno=%d %s (%pV)\n",
+ sb->s_id, function, line, errno, errstr, &vaf);
+ va_end(args);
+ } else {
+ pr_crit("BTRFS: error (device %s) in %s:%d: errno=%d %s\n",
+ sb->s_id, function, line, errno, errstr);
+ }
+#endif
+
+ /*
+ * Today we only save the error info to memory. Long term we'll
+ * also send it down to the disk
+ */
+ set_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state);
+
+ /* Don't go through full error handling during mount */
+ if (!(sb->s_flags & SB_BORN))
+ return;
+
+ if (sb_rdonly(sb))
+ return;
+
+ /* btrfs handle error by forcing the filesystem readonly */
+ sb->s_flags |= SB_RDONLY;
+ btrfs_info(fs_info, "forced readonly");
+ /*
+ * Note that a running device replace operation is not canceled here
+ * although there is no way to update the progress. It would add the
+ * risk of a deadlock, therefore the canceling is omitted. The only
+ * penalty is that some I/O remains active until the procedure
+ * completes. The next time when the filesystem is mounted writeable
+ * again, the device replace operation continues.
+ */
+}
+
+#ifdef CONFIG_PRINTK
+static const char * const logtypes[] = {
+ "emergency",
+ "alert",
+ "critical",
+ "error",
+ "warning",
+ "notice",
+ "info",
+ "debug",
+};
+
+
+/*
+ * Use one ratelimit state per log level so that a flood of less important
+ * messages doesn't cause more important ones to be dropped.
+ */
+static struct ratelimit_state printk_limits[] = {
+ RATELIMIT_STATE_INIT(printk_limits[0], DEFAULT_RATELIMIT_INTERVAL, 100),
+ RATELIMIT_STATE_INIT(printk_limits[1], DEFAULT_RATELIMIT_INTERVAL, 100),
+ RATELIMIT_STATE_INIT(printk_limits[2], DEFAULT_RATELIMIT_INTERVAL, 100),
+ RATELIMIT_STATE_INIT(printk_limits[3], DEFAULT_RATELIMIT_INTERVAL, 100),
+ RATELIMIT_STATE_INIT(printk_limits[4], DEFAULT_RATELIMIT_INTERVAL, 100),
+ RATELIMIT_STATE_INIT(printk_limits[5], DEFAULT_RATELIMIT_INTERVAL, 100),
+ RATELIMIT_STATE_INIT(printk_limits[6], DEFAULT_RATELIMIT_INTERVAL, 100),
+ RATELIMIT_STATE_INIT(printk_limits[7], DEFAULT_RATELIMIT_INTERVAL, 100),
+};
+
+void btrfs_printk(const struct btrfs_fs_info *fs_info, const char *fmt, ...)
+{
+ char lvl[PRINTK_MAX_SINGLE_HEADER_LEN + 1] = "\0";
+ struct va_format vaf;
+ va_list args;
+ int kern_level;
+ const char *type = logtypes[4];
+ struct ratelimit_state *ratelimit = &printk_limits[4];
+
+ va_start(args, fmt);
+
+ while ((kern_level = printk_get_level(fmt)) != 0) {
+ size_t size = printk_skip_level(fmt) - fmt;
+
+ if (kern_level >= '0' && kern_level <= '7') {
+ memcpy(lvl, fmt, size);
+ lvl[size] = '\0';
+ type = logtypes[kern_level - '0'];
+ ratelimit = &printk_limits[kern_level - '0'];
+ }
+ fmt += size;
+ }
+
+ vaf.fmt = fmt;
+ vaf.va = &args;
+
+ if (__ratelimit(ratelimit))
+ printk("%sBTRFS %s (device %s): %pV\n", lvl, type,
+ fs_info ? fs_info->sb->s_id : "<unknown>", &vaf);
+
+ va_end(args);
+}
+#endif
+
+/*
+ * We only mark the transaction aborted and then set the file system read-only.
+ * This will prevent new transactions from starting or trying to join this
+ * one.
+ *
+ * This means that error recovery at the call site is limited to freeing
+ * any local memory allocations and passing the error code up without
+ * further cleanup. The transaction should complete as it normally would
+ * in the call path but will return -EIO.
+ *
+ * We'll complete the cleanup in btrfs_end_transaction and
+ * btrfs_commit_transaction.
+ */
+__cold
+void __btrfs_abort_transaction(struct btrfs_trans_handle *trans,
+ const char *function,
+ unsigned int line, int errno)
+{
+ struct btrfs_fs_info *fs_info = trans->fs_info;
+
+ trans->aborted = errno;
+ /* Nothing used. The other threads that have joined this
+ * transaction may be able to continue. */
+ if (!trans->dirty && list_empty(&trans->new_bgs)) {
+ const char *errstr;
+
+ errstr = btrfs_decode_error(errno);
+ btrfs_warn(fs_info,
+ "%s:%d: Aborting unused transaction(%s).",
+ function, line, errstr);
+ return;
+ }
+ WRITE_ONCE(trans->transaction->aborted, errno);
+ /* Wake up anybody who may be waiting on this transaction */
+ wake_up(&fs_info->transaction_wait);
+ wake_up(&fs_info->transaction_blocked_wait);
+ __btrfs_handle_fs_error(fs_info, function, line, errno, NULL);
+}
+/*
+ * __btrfs_panic decodes unexpected, fatal errors from the caller,
+ * issues an alert, and either panics or BUGs, depending on mount options.
+ */
+__cold
+void __btrfs_panic(struct btrfs_fs_info *fs_info, const char *function,
+ unsigned int line, int errno, const char *fmt, ...)
+{
+ char *s_id = "<unknown>";
+ const char *errstr;
+ struct va_format vaf = { .fmt = fmt };
+ va_list args;
+
+ if (fs_info)
+ s_id = fs_info->sb->s_id;
+
+ va_start(args, fmt);
+ vaf.va = &args;
+
+ errstr = btrfs_decode_error(errno);
+ if (fs_info && (btrfs_test_opt(fs_info, PANIC_ON_FATAL_ERROR)))
+ panic(KERN_CRIT "BTRFS panic (device %s) in %s:%d: %pV (errno=%d %s)\n",
+ s_id, function, line, &vaf, errno, errstr);
+
+ btrfs_crit(fs_info, "panic in %s:%d: %pV (errno=%d %s)",
+ function, line, &vaf, errno, errstr);
+ va_end(args);
+ /* Caller calls BUG() */
+}
+
+static void btrfs_put_super(struct super_block *sb)
+{
+ close_ctree(btrfs_sb(sb));
+}
+
+enum {
+ Opt_acl, Opt_noacl,
+ Opt_clear_cache,
+ Opt_commit_interval,
+ Opt_compress,
+ Opt_compress_force,
+ Opt_compress_force_type,
+ Opt_compress_type,
+ Opt_degraded,
+ Opt_device,
+ Opt_fatal_errors,
+ Opt_flushoncommit, Opt_noflushoncommit,
+ Opt_inode_cache, Opt_noinode_cache,
+ Opt_max_inline,
+ Opt_barrier, Opt_nobarrier,
+ Opt_datacow, Opt_nodatacow,
+ Opt_datasum, Opt_nodatasum,
+ Opt_defrag, Opt_nodefrag,
+ Opt_discard, Opt_nodiscard,
+ Opt_nologreplay,
+ Opt_norecovery,
+ Opt_ratio,
+ Opt_rescan_uuid_tree,
+ Opt_skip_balance,
+ Opt_space_cache, Opt_no_space_cache,
+ Opt_space_cache_version,
+ Opt_ssd, Opt_nossd,
+ Opt_ssd_spread, Opt_nossd_spread,
+ Opt_subvol,
+ Opt_subvol_empty,
+ Opt_subvolid,
+ Opt_thread_pool,
+ Opt_treelog, Opt_notreelog,
+ Opt_usebackuproot,
+ Opt_user_subvol_rm_allowed,
+
+ /* Deprecated options */
+ Opt_alloc_start,
+ Opt_recovery,
+ Opt_subvolrootid,
+
+ /* Debugging options */
+ Opt_check_integrity,
+ Opt_check_integrity_including_extent_data,
+ Opt_check_integrity_print_mask,
+ Opt_enospc_debug, Opt_noenospc_debug,
+#ifdef CONFIG_BTRFS_DEBUG
+ Opt_fragment_data, Opt_fragment_metadata, Opt_fragment_all,
+#endif
+#ifdef CONFIG_BTRFS_FS_REF_VERIFY
+ Opt_ref_verify,
+#endif
+ Opt_err,
+};
+
+static const match_table_t tokens = {
+ {Opt_acl, "acl"},
+ {Opt_noacl, "noacl"},
+ {Opt_clear_cache, "clear_cache"},
+ {Opt_commit_interval, "commit=%u"},
+ {Opt_compress, "compress"},
+ {Opt_compress_type, "compress=%s"},
+ {Opt_compress_force, "compress-force"},
+ {Opt_compress_force_type, "compress-force=%s"},
+ {Opt_degraded, "degraded"},
+ {Opt_device, "device=%s"},
+ {Opt_fatal_errors, "fatal_errors=%s"},
+ {Opt_flushoncommit, "flushoncommit"},
+ {Opt_noflushoncommit, "noflushoncommit"},
+ {Opt_inode_cache, "inode_cache"},
+ {Opt_noinode_cache, "noinode_cache"},
+ {Opt_max_inline, "max_inline=%s"},
+ {Opt_barrier, "barrier"},
+ {Opt_nobarrier, "nobarrier"},
+ {Opt_datacow, "datacow"},
+ {Opt_nodatacow, "nodatacow"},
+ {Opt_datasum, "datasum"},
+ {Opt_nodatasum, "nodatasum"},
+ {Opt_defrag, "autodefrag"},
+ {Opt_nodefrag, "noautodefrag"},
+ {Opt_discard, "discard"},
+ {Opt_nodiscard, "nodiscard"},
+ {Opt_nologreplay, "nologreplay"},
+ {Opt_norecovery, "norecovery"},
+ {Opt_ratio, "metadata_ratio=%u"},
+ {Opt_rescan_uuid_tree, "rescan_uuid_tree"},
+ {Opt_skip_balance, "skip_balance"},
+ {Opt_space_cache, "space_cache"},
+ {Opt_no_space_cache, "nospace_cache"},
+ {Opt_space_cache_version, "space_cache=%s"},
+ {Opt_ssd, "ssd"},
+ {Opt_nossd, "nossd"},
+ {Opt_ssd_spread, "ssd_spread"},
+ {Opt_nossd_spread, "nossd_spread"},
+ {Opt_subvol, "subvol=%s"},
+ {Opt_subvol_empty, "subvol="},
+ {Opt_subvolid, "subvolid=%s"},
+ {Opt_thread_pool, "thread_pool=%u"},
+ {Opt_treelog, "treelog"},
+ {Opt_notreelog, "notreelog"},
+ {Opt_usebackuproot, "usebackuproot"},
+ {Opt_user_subvol_rm_allowed, "user_subvol_rm_allowed"},
+
+ /* Deprecated options */
+ {Opt_alloc_start, "alloc_start=%s"},
+ {Opt_recovery, "recovery"},
+ {Opt_subvolrootid, "subvolrootid=%d"},
+
+ /* Debugging options */
+ {Opt_check_integrity, "check_int"},
+ {Opt_check_integrity_including_extent_data, "check_int_data"},
+ {Opt_check_integrity_print_mask, "check_int_print_mask=%u"},
+ {Opt_enospc_debug, "enospc_debug"},
+ {Opt_noenospc_debug, "noenospc_debug"},
+#ifdef CONFIG_BTRFS_DEBUG
+ {Opt_fragment_data, "fragment=data"},
+ {Opt_fragment_metadata, "fragment=metadata"},
+ {Opt_fragment_all, "fragment=all"},
+#endif
+#ifdef CONFIG_BTRFS_FS_REF_VERIFY
+ {Opt_ref_verify, "ref_verify"},
+#endif
+ {Opt_err, NULL},
+};
+
+/*
+ * Regular mount options parser. Everything that is needed only when
+ * reading in a new superblock is parsed here.
+ * XXX JDM: This needs to be cleaned up for remount.
+ */
+int btrfs_parse_options(struct btrfs_fs_info *info, char *options,
+ unsigned long new_flags)
+{
+ substring_t args[MAX_OPT_ARGS];
+ char *p, *num;
+ u64 cache_gen;
+ int intarg;
+ int ret = 0;
+ char *compress_type;
+ bool compress_force = false;
+ enum btrfs_compression_type saved_compress_type;
+ bool saved_compress_force;
+ int no_compress = 0;
+
+ cache_gen = btrfs_super_cache_generation(info->super_copy);
+ if (btrfs_fs_compat_ro(info, FREE_SPACE_TREE))
+ btrfs_set_opt(info->mount_opt, FREE_SPACE_TREE);
+ else if (cache_gen)
+ btrfs_set_opt(info->mount_opt, SPACE_CACHE);
+
+ /*
+ * Even the options are empty, we still need to do extra check
+ * against new flags
+ */
+ if (!options)
+ goto check;
+
+ while ((p = strsep(&options, ",")) != NULL) {
+ int token;
+ if (!*p)
+ continue;
+
+ token = match_token(p, tokens, args);
+ switch (token) {
+ case Opt_degraded:
+ btrfs_info(info, "allowing degraded mounts");
+ btrfs_set_opt(info->mount_opt, DEGRADED);
+ break;
+ case Opt_subvol:
+ case Opt_subvol_empty:
+ case Opt_subvolid:
+ case Opt_subvolrootid:
+ case Opt_device:
+ /*
+ * These are parsed by btrfs_parse_subvol_options or
+ * btrfs_parse_device_options and can be ignored here.
+ */
+ break;
+ case Opt_nodatasum:
+ btrfs_set_and_info(info, NODATASUM,
+ "setting nodatasum");
+ break;
+ case Opt_datasum:
+ if (btrfs_test_opt(info, NODATASUM)) {
+ if (btrfs_test_opt(info, NODATACOW))
+ btrfs_info(info,
+ "setting datasum, datacow enabled");
+ else
+ btrfs_info(info, "setting datasum");
+ }
+ btrfs_clear_opt(info->mount_opt, NODATACOW);
+ btrfs_clear_opt(info->mount_opt, NODATASUM);
+ break;
+ case Opt_nodatacow:
+ if (!btrfs_test_opt(info, NODATACOW)) {
+ if (!btrfs_test_opt(info, COMPRESS) ||
+ !btrfs_test_opt(info, FORCE_COMPRESS)) {
+ btrfs_info(info,
+ "setting nodatacow, compression disabled");
+ } else {
+ btrfs_info(info, "setting nodatacow");
+ }
+ }
+ btrfs_clear_opt(info->mount_opt, COMPRESS);
+ btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
+ btrfs_set_opt(info->mount_opt, NODATACOW);
+ btrfs_set_opt(info->mount_opt, NODATASUM);
+ break;
+ case Opt_datacow:
+ btrfs_clear_and_info(info, NODATACOW,
+ "setting datacow");
+ break;
+ case Opt_compress_force:
+ case Opt_compress_force_type:
+ compress_force = true;
+ /* Fallthrough */
+ case Opt_compress:
+ case Opt_compress_type:
+ saved_compress_type = btrfs_test_opt(info,
+ COMPRESS) ?
+ info->compress_type : BTRFS_COMPRESS_NONE;
+ saved_compress_force =
+ btrfs_test_opt(info, FORCE_COMPRESS);
+ if (token == Opt_compress ||
+ token == Opt_compress_force ||
+ strncmp(args[0].from, "zlib", 4) == 0) {
+ compress_type = "zlib";
+
+ info->compress_type = BTRFS_COMPRESS_ZLIB;
+ info->compress_level = BTRFS_ZLIB_DEFAULT_LEVEL;
+ /*
+ * args[0] contains uninitialized data since
+ * for these tokens we don't expect any
+ * parameter.
+ */
+ if (token != Opt_compress &&
+ token != Opt_compress_force)
+ info->compress_level =
+ btrfs_compress_str2level(args[0].from);
+ btrfs_set_opt(info->mount_opt, COMPRESS);
+ btrfs_clear_opt(info->mount_opt, NODATACOW);
+ btrfs_clear_opt(info->mount_opt, NODATASUM);
+ no_compress = 0;
+ } else if (strncmp(args[0].from, "lzo", 3) == 0) {
+ compress_type = "lzo";
+ info->compress_type = BTRFS_COMPRESS_LZO;
+ btrfs_set_opt(info->mount_opt, COMPRESS);
+ btrfs_clear_opt(info->mount_opt, NODATACOW);
+ btrfs_clear_opt(info->mount_opt, NODATASUM);
+ btrfs_set_fs_incompat(info, COMPRESS_LZO);
+ no_compress = 0;
+ } else if (strcmp(args[0].from, "zstd") == 0) {
+ compress_type = "zstd";
+ info->compress_type = BTRFS_COMPRESS_ZSTD;
+ btrfs_set_opt(info->mount_opt, COMPRESS);
+ btrfs_clear_opt(info->mount_opt, NODATACOW);
+ btrfs_clear_opt(info->mount_opt, NODATASUM);
+ btrfs_set_fs_incompat(info, COMPRESS_ZSTD);
+ no_compress = 0;
+ } else if (strncmp(args[0].from, "no", 2) == 0) {
+ compress_type = "no";
+ btrfs_clear_opt(info->mount_opt, COMPRESS);
+ btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
+ compress_force = false;
+ no_compress++;
+ } else {
+ ret = -EINVAL;
+ goto out;
+ }
+
+ if (compress_force) {
+ btrfs_set_opt(info->mount_opt, FORCE_COMPRESS);
+ } else {
+ /*
+ * If we remount from compress-force=xxx to
+ * compress=xxx, we need clear FORCE_COMPRESS
+ * flag, otherwise, there is no way for users
+ * to disable forcible compression separately.
+ */
+ btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
+ }
+ if ((btrfs_test_opt(info, COMPRESS) &&
+ (info->compress_type != saved_compress_type ||
+ compress_force != saved_compress_force)) ||
+ (!btrfs_test_opt(info, COMPRESS) &&
+ no_compress == 1)) {
+ btrfs_info(info, "%s %s compression, level %d",
+ (compress_force) ? "force" : "use",
+ compress_type, info->compress_level);
+ }
+ compress_force = false;
+ break;
+ case Opt_ssd:
+ btrfs_set_and_info(info, SSD,
+ "enabling ssd optimizations");
+ btrfs_clear_opt(info->mount_opt, NOSSD);
+ break;
+ case Opt_ssd_spread:
+ btrfs_set_and_info(info, SSD,
+ "enabling ssd optimizations");
+ btrfs_set_and_info(info, SSD_SPREAD,
+ "using spread ssd allocation scheme");
+ btrfs_clear_opt(info->mount_opt, NOSSD);
+ break;
+ case Opt_nossd:
+ btrfs_set_opt(info->mount_opt, NOSSD);
+ btrfs_clear_and_info(info, SSD,
+ "not using ssd optimizations");
+ /* Fallthrough */
+ case Opt_nossd_spread:
+ btrfs_clear_and_info(info, SSD_SPREAD,
+ "not using spread ssd allocation scheme");
+ break;
+ case Opt_barrier:
+ btrfs_clear_and_info(info, NOBARRIER,
+ "turning on barriers");
+ break;
+ case Opt_nobarrier:
+ btrfs_set_and_info(info, NOBARRIER,
+ "turning off barriers");
+ break;
+ case Opt_thread_pool:
+ ret = match_int(&args[0], &intarg);
+ if (ret) {
+ goto out;
+ } else if (intarg == 0) {
+ ret = -EINVAL;
+ goto out;
+ }
+ info->thread_pool_size = intarg;
+ break;
+ case Opt_max_inline:
+ num = match_strdup(&args[0]);
+ if (num) {
+ info->max_inline = memparse(num, NULL);
+ kfree(num);
+
+ if (info->max_inline) {
+ info->max_inline = min_t(u64,
+ info->max_inline,
+ info->sectorsize);
+ }
+ btrfs_info(info, "max_inline at %llu",
+ info->max_inline);
+ } else {
+ ret = -ENOMEM;
+ goto out;
+ }
+ break;
+ case Opt_alloc_start:
+ btrfs_info(info,
+ "option alloc_start is obsolete, ignored");
+ break;
+ case Opt_acl:
+#ifdef CONFIG_BTRFS_FS_POSIX_ACL
+ info->sb->s_flags |= SB_POSIXACL;
+ break;
+#else
+ btrfs_err(info, "support for ACL not compiled in!");
+ ret = -EINVAL;
+ goto out;
+#endif
+ case Opt_noacl:
+ info->sb->s_flags &= ~SB_POSIXACL;
+ break;
+ case Opt_notreelog:
+ btrfs_set_and_info(info, NOTREELOG,
+ "disabling tree log");
+ break;
+ case Opt_treelog:
+ btrfs_clear_and_info(info, NOTREELOG,
+ "enabling tree log");
+ break;
+ case Opt_norecovery:
+ case Opt_nologreplay:
+ btrfs_set_and_info(info, NOLOGREPLAY,
+ "disabling log replay at mount time");
+ break;
+ case Opt_flushoncommit:
+ btrfs_set_and_info(info, FLUSHONCOMMIT,
+ "turning on flush-on-commit");
+ break;
+ case Opt_noflushoncommit:
+ btrfs_clear_and_info(info, FLUSHONCOMMIT,
+ "turning off flush-on-commit");
+ break;
+ case Opt_ratio:
+ ret = match_int(&args[0], &intarg);
+ if (ret)
+ goto out;
+ info->metadata_ratio = intarg;
+ btrfs_info(info, "metadata ratio %u",
+ info->metadata_ratio);
+ break;
+ case Opt_discard:
+ btrfs_set_and_info(info, DISCARD,
+ "turning on discard");
+ break;
+ case Opt_nodiscard:
+ btrfs_clear_and_info(info, DISCARD,
+ "turning off discard");
+ break;
+ case Opt_space_cache:
+ case Opt_space_cache_version:
+ if (token == Opt_space_cache ||
+ strcmp(args[0].from, "v1") == 0) {
+ btrfs_clear_opt(info->mount_opt,
+ FREE_SPACE_TREE);
+ btrfs_set_and_info(info, SPACE_CACHE,
+ "enabling disk space caching");
+ } else if (strcmp(args[0].from, "v2") == 0) {
+ btrfs_clear_opt(info->mount_opt,
+ SPACE_CACHE);
+ btrfs_set_and_info(info, FREE_SPACE_TREE,
+ "enabling free space tree");
+ } else {
+ ret = -EINVAL;
+ goto out;
+ }
+ break;
+ case Opt_rescan_uuid_tree:
+ btrfs_set_opt(info->mount_opt, RESCAN_UUID_TREE);
+ break;
+ case Opt_no_space_cache:
+ if (btrfs_test_opt(info, SPACE_CACHE)) {
+ btrfs_clear_and_info(info, SPACE_CACHE,
+ "disabling disk space caching");
+ }
+ if (btrfs_test_opt(info, FREE_SPACE_TREE)) {
+ btrfs_clear_and_info(info, FREE_SPACE_TREE,
+ "disabling free space tree");
+ }
+ break;
+ case Opt_inode_cache:
+ btrfs_set_pending_and_info(info, INODE_MAP_CACHE,
+ "enabling inode map caching");
+ break;
+ case Opt_noinode_cache:
+ btrfs_clear_pending_and_info(info, INODE_MAP_CACHE,
+ "disabling inode map caching");
+ break;
+ case Opt_clear_cache:
+ btrfs_set_and_info(info, CLEAR_CACHE,
+ "force clearing of disk cache");
+ break;
+ case Opt_user_subvol_rm_allowed:
+ btrfs_set_opt(info->mount_opt, USER_SUBVOL_RM_ALLOWED);
+ break;
+ case Opt_enospc_debug:
+ btrfs_set_opt(info->mount_opt, ENOSPC_DEBUG);
+ break;
+ case Opt_noenospc_debug:
+ btrfs_clear_opt(info->mount_opt, ENOSPC_DEBUG);
+ break;
+ case Opt_defrag:
+ btrfs_set_and_info(info, AUTO_DEFRAG,
+ "enabling auto defrag");
+ break;
+ case Opt_nodefrag:
+ btrfs_clear_and_info(info, AUTO_DEFRAG,
+ "disabling auto defrag");
+ break;
+ case Opt_recovery:
+ btrfs_warn(info,
+ "'recovery' is deprecated, use 'usebackuproot' instead");
+ /* fall through */
+ case Opt_usebackuproot:
+ btrfs_info(info,
+ "trying to use backup root at mount time");
+ btrfs_set_opt(info->mount_opt, USEBACKUPROOT);
+ break;
+ case Opt_skip_balance:
+ btrfs_set_opt(info->mount_opt, SKIP_BALANCE);
+ break;
+#ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
+ case Opt_check_integrity_including_extent_data:
+ btrfs_info(info,
+ "enabling check integrity including extent data");
+ btrfs_set_opt(info->mount_opt,
+ CHECK_INTEGRITY_INCLUDING_EXTENT_DATA);
+ btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY);
+ break;
+ case Opt_check_integrity:
+ btrfs_info(info, "enabling check integrity");
+ btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY);
+ break;
+ case Opt_check_integrity_print_mask:
+ ret = match_int(&args[0], &intarg);
+ if (ret)
+ goto out;
+ info->check_integrity_print_mask = intarg;
+ btrfs_info(info, "check_integrity_print_mask 0x%x",
+ info->check_integrity_print_mask);
+ break;
+#else
+ case Opt_check_integrity_including_extent_data:
+ case Opt_check_integrity:
+ case Opt_check_integrity_print_mask:
+ btrfs_err(info,
+ "support for check_integrity* not compiled in!");
+ ret = -EINVAL;
+ goto out;
+#endif
+ case Opt_fatal_errors:
+ if (strcmp(args[0].from, "panic") == 0)
+ btrfs_set_opt(info->mount_opt,
+ PANIC_ON_FATAL_ERROR);
+ else if (strcmp(args[0].from, "bug") == 0)
+ btrfs_clear_opt(info->mount_opt,
+ PANIC_ON_FATAL_ERROR);
+ else {
+ ret = -EINVAL;
+ goto out;
+ }
+ break;
+ case Opt_commit_interval:
+ intarg = 0;
+ ret = match_int(&args[0], &intarg);
+ if (ret)
+ goto out;
+ if (intarg == 0) {
+ btrfs_info(info,
+ "using default commit interval %us",
+ BTRFS_DEFAULT_COMMIT_INTERVAL);
+ intarg = BTRFS_DEFAULT_COMMIT_INTERVAL;
+ } else if (intarg > 300) {
+ btrfs_warn(info, "excessive commit interval %d",
+ intarg);
+ }
+ info->commit_interval = intarg;
+ break;
+#ifdef CONFIG_BTRFS_DEBUG
+ case Opt_fragment_all:
+ btrfs_info(info, "fragmenting all space");
+ btrfs_set_opt(info->mount_opt, FRAGMENT_DATA);
+ btrfs_set_opt(info->mount_opt, FRAGMENT_METADATA);
+ break;
+ case Opt_fragment_metadata:
+ btrfs_info(info, "fragmenting metadata");
+ btrfs_set_opt(info->mount_opt,
+ FRAGMENT_METADATA);
+ break;
+ case Opt_fragment_data:
+ btrfs_info(info, "fragmenting data");
+ btrfs_set_opt(info->mount_opt, FRAGMENT_DATA);
+ break;
+#endif
+#ifdef CONFIG_BTRFS_FS_REF_VERIFY
+ case Opt_ref_verify:
+ btrfs_info(info, "doing ref verification");
+ btrfs_set_opt(info->mount_opt, REF_VERIFY);
+ break;
+#endif
+ case Opt_err:
+ btrfs_info(info, "unrecognized mount option '%s'", p);
+ ret = -EINVAL;
+ goto out;
+ default:
+ break;
+ }
+ }
+check:
+ /*
+ * Extra check for current option against current flag
+ */
+ if (btrfs_test_opt(info, NOLOGREPLAY) && !(new_flags & SB_RDONLY)) {
+ btrfs_err(info,
+ "nologreplay must be used with ro mount option");
+ ret = -EINVAL;
+ }
+out:
+ if (btrfs_fs_compat_ro(info, FREE_SPACE_TREE) &&
+ !btrfs_test_opt(info, FREE_SPACE_TREE) &&
+ !btrfs_test_opt(info, CLEAR_CACHE)) {
+ btrfs_err(info, "cannot disable free space tree");
+ ret = -EINVAL;
+
+ }
+ if (!ret && btrfs_test_opt(info, SPACE_CACHE))
+ btrfs_info(info, "disk space caching is enabled");
+ if (!ret && btrfs_test_opt(info, FREE_SPACE_TREE))
+ btrfs_info(info, "using free space tree");
+ return ret;
+}
+
+/*
+ * Parse mount options that are required early in the mount process.
+ *
+ * All other options will be parsed on much later in the mount process and
+ * only when we need to allocate a new super block.
+ */
+static int btrfs_parse_device_options(const char *options, fmode_t flags,
+ void *holder)
+{
+ substring_t args[MAX_OPT_ARGS];
+ char *device_name, *opts, *orig, *p;
+ struct btrfs_device *device = NULL;
+ int error = 0;
+
+ lockdep_assert_held(&uuid_mutex);
+
+ if (!options)
+ return 0;
+
+ /*
+ * strsep changes the string, duplicate it because btrfs_parse_options
+ * gets called later
+ */
+ opts = kstrdup(options, GFP_KERNEL);
+ if (!opts)
+ return -ENOMEM;
+ orig = opts;
+
+ while ((p = strsep(&opts, ",")) != NULL) {
+ int token;
+
+ if (!*p)
+ continue;
+
+ token = match_token(p, tokens, args);
+ if (token == Opt_device) {
+ device_name = match_strdup(&args[0]);
+ if (!device_name) {
+ error = -ENOMEM;
+ goto out;
+ }
+ device = btrfs_scan_one_device(device_name, flags,
+ holder);
+ kfree(device_name);
+ if (IS_ERR(device)) {
+ error = PTR_ERR(device);
+ goto out;
+ }
+ }
+ }
+
+out:
+ kfree(orig);
+ return error;
+}
+
+/*
+ * Parse mount options that are related to subvolume id
+ *
+ * The value is later passed to mount_subvol()
+ */
+static int btrfs_parse_subvol_options(const char *options, char **subvol_name,
+ u64 *subvol_objectid)
+{
+ substring_t args[MAX_OPT_ARGS];
+ char *opts, *orig, *p;
+ int error = 0;
+ u64 subvolid;
+
+ if (!options)
+ return 0;
+
+ /*
+ * strsep changes the string, duplicate it because
+ * btrfs_parse_device_options gets called later
+ */
+ opts = kstrdup(options, GFP_KERNEL);
+ if (!opts)
+ return -ENOMEM;
+ orig = opts;
+
+ while ((p = strsep(&opts, ",")) != NULL) {
+ int token;
+ if (!*p)
+ continue;
+
+ token = match_token(p, tokens, args);
+ switch (token) {
+ case Opt_subvol:
+ kfree(*subvol_name);
+ *subvol_name = match_strdup(&args[0]);
+ if (!*subvol_name) {
+ error = -ENOMEM;
+ goto out;
+ }
+ break;
+ case Opt_subvolid:
+ error = match_u64(&args[0], &subvolid);
+ if (error)
+ goto out;
+
+ /* we want the original fs_tree */
+ if (subvolid == 0)
+ subvolid = BTRFS_FS_TREE_OBJECTID;
+
+ *subvol_objectid = subvolid;
+ break;
+ case Opt_subvolrootid:
+ pr_warn("BTRFS: 'subvolrootid' mount option is deprecated and has no effect\n");
+ break;
+ default:
+ break;
+ }
+ }
+
+out:
+ kfree(orig);
+ return error;
+}
+
+static char *get_subvol_name_from_objectid(struct btrfs_fs_info *fs_info,
+ u64 subvol_objectid)
+{
+ struct btrfs_root *root = fs_info->tree_root;
+ struct btrfs_root *fs_root;
+ struct btrfs_root_ref *root_ref;
+ struct btrfs_inode_ref *inode_ref;
+ struct btrfs_key key;
+ struct btrfs_path *path = NULL;
+ char *name = NULL, *ptr;
+ u64 dirid;
+ int len;
+ int ret;
+
+ path = btrfs_alloc_path();
+ if (!path) {
+ ret = -ENOMEM;
+ goto err;
+ }
+ path->leave_spinning = 1;
+
+ name = kmalloc(PATH_MAX, GFP_KERNEL);
+ if (!name) {
+ ret = -ENOMEM;
+ goto err;
+ }
+ ptr = name + PATH_MAX - 1;
+ ptr[0] = '\0';
+
+ /*
+ * Walk up the subvolume trees in the tree of tree roots by root
+ * backrefs until we hit the top-level subvolume.
+ */
+ while (subvol_objectid != BTRFS_FS_TREE_OBJECTID) {
+ key.objectid = subvol_objectid;
+ key.type = BTRFS_ROOT_BACKREF_KEY;
+ key.offset = (u64)-1;
+
+ ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
+ if (ret < 0) {
+ goto err;
+ } else if (ret > 0) {
+ ret = btrfs_previous_item(root, path, subvol_objectid,
+ BTRFS_ROOT_BACKREF_KEY);
+ if (ret < 0) {
+ goto err;
+ } else if (ret > 0) {
+ ret = -ENOENT;
+ goto err;
+ }
+ }
+
+ btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
+ subvol_objectid = key.offset;
+
+ root_ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
+ struct btrfs_root_ref);
+ len = btrfs_root_ref_name_len(path->nodes[0], root_ref);
+ ptr -= len + 1;
+ if (ptr < name) {
+ ret = -ENAMETOOLONG;
+ goto err;
+ }
+ read_extent_buffer(path->nodes[0], ptr + 1,
+ (unsigned long)(root_ref + 1), len);
+ ptr[0] = '/';
+ dirid = btrfs_root_ref_dirid(path->nodes[0], root_ref);
+ btrfs_release_path(path);
+
+ key.objectid = subvol_objectid;
+ key.type = BTRFS_ROOT_ITEM_KEY;
+ key.offset = (u64)-1;
+ fs_root = btrfs_read_fs_root_no_name(fs_info, &key);
+ if (IS_ERR(fs_root)) {
+ ret = PTR_ERR(fs_root);
+ goto err;
+ }
+
+ /*
+ * Walk up the filesystem tree by inode refs until we hit the
+ * root directory.
+ */
+ while (dirid != BTRFS_FIRST_FREE_OBJECTID) {
+ key.objectid = dirid;
+ key.type = BTRFS_INODE_REF_KEY;
+ key.offset = (u64)-1;
+
+ ret = btrfs_search_slot(NULL, fs_root, &key, path, 0, 0);
+ if (ret < 0) {
+ goto err;
+ } else if (ret > 0) {
+ ret = btrfs_previous_item(fs_root, path, dirid,
+ BTRFS_INODE_REF_KEY);
+ if (ret < 0) {
+ goto err;
+ } else if (ret > 0) {
+ ret = -ENOENT;
+ goto err;
+ }
+ }
+
+ btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
+ dirid = key.offset;
+
+ inode_ref = btrfs_item_ptr(path->nodes[0],
+ path->slots[0],
+ struct btrfs_inode_ref);
+ len = btrfs_inode_ref_name_len(path->nodes[0],
+ inode_ref);
+ ptr -= len + 1;
+ if (ptr < name) {
+ ret = -ENAMETOOLONG;
+ goto err;
+ }
+ read_extent_buffer(path->nodes[0], ptr + 1,
+ (unsigned long)(inode_ref + 1), len);
+ ptr[0] = '/';
+ btrfs_release_path(path);
+ }
+ }
+
+ btrfs_free_path(path);
+ if (ptr == name + PATH_MAX - 1) {
+ name[0] = '/';
+ name[1] = '\0';
+ } else {
+ memmove(name, ptr, name + PATH_MAX - ptr);
+ }
+ return name;
+
+err:
+ btrfs_free_path(path);
+ kfree(name);
+ return ERR_PTR(ret);
+}
+
+static int get_default_subvol_objectid(struct btrfs_fs_info *fs_info, u64 *objectid)
+{
+ struct btrfs_root *root = fs_info->tree_root;
+ struct btrfs_dir_item *di;
+ struct btrfs_path *path;
+ struct btrfs_key location;
+ u64 dir_id;
+
+ path = btrfs_alloc_path();
+ if (!path)
+ return -ENOMEM;
+ path->leave_spinning = 1;
+
+ /*
+ * Find the "default" dir item which points to the root item that we
+ * will mount by default if we haven't been given a specific subvolume
+ * to mount.
+ */
+ dir_id = btrfs_super_root_dir(fs_info->super_copy);
+ di = btrfs_lookup_dir_item(NULL, root, path, dir_id, "default", 7, 0);
+ if (IS_ERR(di)) {
+ btrfs_free_path(path);
+ return PTR_ERR(di);
+ }
+ if (!di) {
+ /*
+ * Ok the default dir item isn't there. This is weird since
+ * it's always been there, but don't freak out, just try and
+ * mount the top-level subvolume.
+ */
+ btrfs_free_path(path);
+ *objectid = BTRFS_FS_TREE_OBJECTID;
+ return 0;
+ }
+
+ btrfs_dir_item_key_to_cpu(path->nodes[0], di, &location);
+ btrfs_free_path(path);
+ *objectid = location.objectid;
+ return 0;
+}
+
+static int btrfs_fill_super(struct super_block *sb,
+ struct btrfs_fs_devices *fs_devices,
+ void *data)
+{
+ struct inode *inode;
+ struct btrfs_fs_info *fs_info = btrfs_sb(sb);
+ struct btrfs_key key;
+ int err;
+
+ sb->s_maxbytes = MAX_LFS_FILESIZE;
+ sb->s_magic = BTRFS_SUPER_MAGIC;
+ sb->s_op = &btrfs_super_ops;
+ sb->s_d_op = &btrfs_dentry_operations;
+ sb->s_export_op = &btrfs_export_ops;
+ sb->s_xattr = btrfs_xattr_handlers;
+ sb->s_time_gran = 1;
+#ifdef CONFIG_BTRFS_FS_POSIX_ACL
+ sb->s_flags |= SB_POSIXACL;
+#endif
+ sb->s_flags |= SB_I_VERSION;
+ sb->s_iflags |= SB_I_CGROUPWB;
+
+ err = super_setup_bdi(sb);
+ if (err) {
+ btrfs_err(fs_info, "super_setup_bdi failed");
+ return err;
+ }
+
+ err = open_ctree(sb, fs_devices, (char *)data);
+ if (err) {
+ btrfs_err(fs_info, "open_ctree failed");
+ return err;
+ }
+
+ key.objectid = BTRFS_FIRST_FREE_OBJECTID;
+ key.type = BTRFS_INODE_ITEM_KEY;
+ key.offset = 0;
+ inode = btrfs_iget(sb, &key, fs_info->fs_root, NULL);
+ if (IS_ERR(inode)) {
+ err = PTR_ERR(inode);
+ goto fail_close;
+ }
+
+ sb->s_root = d_make_root(inode);
+ if (!sb->s_root) {
+ err = -ENOMEM;
+ goto fail_close;
+ }
+
+ cleancache_init_fs(sb);
+ sb->s_flags |= SB_ACTIVE;
+ return 0;
+
+fail_close:
+ close_ctree(fs_info);
+ return err;
+}
+
+int btrfs_sync_fs(struct super_block *sb, int wait)
+{
+ struct btrfs_trans_handle *trans;
+ struct btrfs_fs_info *fs_info = btrfs_sb(sb);
+ struct btrfs_root *root = fs_info->tree_root;
+
+ trace_btrfs_sync_fs(fs_info, wait);
+
+ if (!wait) {
+ filemap_flush(fs_info->btree_inode->i_mapping);
+ return 0;
+ }
+
+ btrfs_wait_ordered_roots(fs_info, U64_MAX, 0, (u64)-1);
+
+ trans = btrfs_attach_transaction_barrier(root);
+ if (IS_ERR(trans)) {
+ /* no transaction, don't bother */
+ if (PTR_ERR(trans) == -ENOENT) {
+ /*
+ * Exit unless we have some pending changes
+ * that need to go through commit
+ */
+ if (fs_info->pending_changes == 0)
+ return 0;
+ /*
+ * A non-blocking test if the fs is frozen. We must not
+ * start a new transaction here otherwise a deadlock
+ * happens. The pending operations are delayed to the
+ * next commit after thawing.
+ */
+ if (sb_start_write_trylock(sb))
+ sb_end_write(sb);
+ else
+ return 0;
+ trans = btrfs_start_transaction(root, 0);
+ }
+ if (IS_ERR(trans))
+ return PTR_ERR(trans);
+ }
+ return btrfs_commit_transaction(trans);
+}
+
+static int btrfs_show_options(struct seq_file *seq, struct dentry *dentry)
+{
+ struct btrfs_fs_info *info = btrfs_sb(dentry->d_sb);
+ const char *compress_type;
+
+ if (btrfs_test_opt(info, DEGRADED))
+ seq_puts(seq, ",degraded");
+ if (btrfs_test_opt(info, NODATASUM))
+ seq_puts(seq, ",nodatasum");
+ if (btrfs_test_opt(info, NODATACOW))
+ seq_puts(seq, ",nodatacow");
+ if (btrfs_test_opt(info, NOBARRIER))
+ seq_puts(seq, ",nobarrier");
+ if (info->max_inline != BTRFS_DEFAULT_MAX_INLINE)
+ seq_printf(seq, ",max_inline=%llu", info->max_inline);
+ if (info->thread_pool_size != min_t(unsigned long,
+ num_online_cpus() + 2, 8))
+ seq_printf(seq, ",thread_pool=%u", info->thread_pool_size);
+ if (btrfs_test_opt(info, COMPRESS)) {
+ compress_type = btrfs_compress_type2str(info->compress_type);
+ if (btrfs_test_opt(info, FORCE_COMPRESS))
+ seq_printf(seq, ",compress-force=%s", compress_type);
+ else
+ seq_printf(seq, ",compress=%s", compress_type);
+ if (info->compress_level)
+ seq_printf(seq, ":%d", info->compress_level);
+ }
+ if (btrfs_test_opt(info, NOSSD))
+ seq_puts(seq, ",nossd");
+ if (btrfs_test_opt(info, SSD_SPREAD))
+ seq_puts(seq, ",ssd_spread");
+ else if (btrfs_test_opt(info, SSD))
+ seq_puts(seq, ",ssd");
+ if (btrfs_test_opt(info, NOTREELOG))
+ seq_puts(seq, ",notreelog");
+ if (btrfs_test_opt(info, NOLOGREPLAY))
+ seq_puts(seq, ",nologreplay");
+ if (btrfs_test_opt(info, FLUSHONCOMMIT))
+ seq_puts(seq, ",flushoncommit");
+ if (btrfs_test_opt(info, DISCARD))
+ seq_puts(seq, ",discard");
+ if (!(info->sb->s_flags & SB_POSIXACL))
+ seq_puts(seq, ",noacl");
+ if (btrfs_test_opt(info, SPACE_CACHE))
+ seq_puts(seq, ",space_cache");
+ else if (btrfs_test_opt(info, FREE_SPACE_TREE))
+ seq_puts(seq, ",space_cache=v2");
+ else
+ seq_puts(seq, ",nospace_cache");
+ if (btrfs_test_opt(info, RESCAN_UUID_TREE))
+ seq_puts(seq, ",rescan_uuid_tree");
+ if (btrfs_test_opt(info, CLEAR_CACHE))
+ seq_puts(seq, ",clear_cache");
+ if (btrfs_test_opt(info, USER_SUBVOL_RM_ALLOWED))
+ seq_puts(seq, ",user_subvol_rm_allowed");
+ if (btrfs_test_opt(info, ENOSPC_DEBUG))
+ seq_puts(seq, ",enospc_debug");
+ if (btrfs_test_opt(info, AUTO_DEFRAG))
+ seq_puts(seq, ",autodefrag");
+ if (btrfs_test_opt(info, INODE_MAP_CACHE))
+ seq_puts(seq, ",inode_cache");
+ if (btrfs_test_opt(info, SKIP_BALANCE))
+ seq_puts(seq, ",skip_balance");
+#ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
+ if (btrfs_test_opt(info, CHECK_INTEGRITY_INCLUDING_EXTENT_DATA))
+ seq_puts(seq, ",check_int_data");
+ else if (btrfs_test_opt(info, CHECK_INTEGRITY))
+ seq_puts(seq, ",check_int");
+ if (info->check_integrity_print_mask)
+ seq_printf(seq, ",check_int_print_mask=%d",
+ info->check_integrity_print_mask);
+#endif
+ if (info->metadata_ratio)
+ seq_printf(seq, ",metadata_ratio=%u", info->metadata_ratio);
+ if (btrfs_test_opt(info, PANIC_ON_FATAL_ERROR))
+ seq_puts(seq, ",fatal_errors=panic");
+ if (info->commit_interval != BTRFS_DEFAULT_COMMIT_INTERVAL)
+ seq_printf(seq, ",commit=%u", info->commit_interval);
+#ifdef CONFIG_BTRFS_DEBUG
+ if (btrfs_test_opt(info, FRAGMENT_DATA))
+ seq_puts(seq, ",fragment=data");
+ if (btrfs_test_opt(info, FRAGMENT_METADATA))
+ seq_puts(seq, ",fragment=metadata");
+#endif
+ if (btrfs_test_opt(info, REF_VERIFY))
+ seq_puts(seq, ",ref_verify");
+ seq_printf(seq, ",subvolid=%llu",
+ BTRFS_I(d_inode(dentry))->root->root_key.objectid);
+ seq_puts(seq, ",subvol=");
+ seq_dentry(seq, dentry, " \t\n\\");
+ return 0;
+}
+
+static int btrfs_test_super(struct super_block *s, void *data)
+{
+ struct btrfs_fs_info *p = data;
+ struct btrfs_fs_info *fs_info = btrfs_sb(s);
+
+ return fs_info->fs_devices == p->fs_devices;
+}
+
+static int btrfs_set_super(struct super_block *s, void *data)
+{
+ int err = set_anon_super(s, data);
+ if (!err)
+ s->s_fs_info = data;
+ return err;
+}
+
+/*
+ * subvolumes are identified by ino 256
+ */
+static inline int is_subvolume_inode(struct inode *inode)
+{
+ if (inode && inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)
+ return 1;
+ return 0;
+}
+
+static struct dentry *mount_subvol(const char *subvol_name, u64 subvol_objectid,
+ const char *device_name, struct vfsmount *mnt)
+{
+ struct dentry *root;
+ int ret;
+
+ if (!subvol_name) {
+ if (!subvol_objectid) {
+ ret = get_default_subvol_objectid(btrfs_sb(mnt->mnt_sb),
+ &subvol_objectid);
+ if (ret) {
+ root = ERR_PTR(ret);
+ goto out;
+ }
+ }
+ subvol_name = get_subvol_name_from_objectid(btrfs_sb(mnt->mnt_sb),
+ subvol_objectid);
+ if (IS_ERR(subvol_name)) {
+ root = ERR_CAST(subvol_name);
+ subvol_name = NULL;
+ goto out;
+ }
+
+ }
+
+ root = mount_subtree(mnt, subvol_name);
+ /* mount_subtree() drops our reference on the vfsmount. */
+ mnt = NULL;
+
+ if (!IS_ERR(root)) {
+ struct super_block *s = root->d_sb;
+ struct btrfs_fs_info *fs_info = btrfs_sb(s);
+ struct inode *root_inode = d_inode(root);
+ u64 root_objectid = BTRFS_I(root_inode)->root->root_key.objectid;
+
+ ret = 0;
+ if (!is_subvolume_inode(root_inode)) {
+ btrfs_err(fs_info, "'%s' is not a valid subvolume",
+ subvol_name);
+ ret = -EINVAL;
+ }
+ if (subvol_objectid && root_objectid != subvol_objectid) {
+ /*
+ * This will also catch a race condition where a
+ * subvolume which was passed by ID is renamed and
+ * another subvolume is renamed over the old location.
+ */
+ btrfs_err(fs_info,
+ "subvol '%s' does not match subvolid %llu",
+ subvol_name, subvol_objectid);
+ ret = -EINVAL;
+ }
+ if (ret) {
+ dput(root);
+ root = ERR_PTR(ret);
+ deactivate_locked_super(s);
+ }
+ }
+
+out:
+ mntput(mnt);
+ kfree(subvol_name);
+ return root;
+}
+
+static int parse_security_options(char *orig_opts,
+ struct security_mnt_opts *sec_opts)
+{
+ char *secdata = NULL;
+ int ret = 0;
+
+ secdata = alloc_secdata();
+ if (!secdata)
+ return -ENOMEM;
+ ret = security_sb_copy_data(orig_opts, secdata);
+ if (ret) {
+ free_secdata(secdata);
+ return ret;
+ }
+ ret = security_sb_parse_opts_str(secdata, sec_opts);
+ free_secdata(secdata);
+ return ret;
+}
+
+static int setup_security_options(struct btrfs_fs_info *fs_info,
+ struct super_block *sb,
+ struct security_mnt_opts *sec_opts)
+{
+ int ret = 0;
+
+ /*
+ * Call security_sb_set_mnt_opts() to check whether new sec_opts
+ * is valid.
+ */
+ ret = security_sb_set_mnt_opts(sb, sec_opts, 0, NULL);
+ if (ret)
+ return ret;
+
+#ifdef CONFIG_SECURITY
+ if (!fs_info->security_opts.num_mnt_opts) {
+ /* first time security setup, copy sec_opts to fs_info */
+ memcpy(&fs_info->security_opts, sec_opts, sizeof(*sec_opts));
+ } else {
+ /*
+ * Since SELinux (the only one supporting security_mnt_opts)
+ * does NOT support changing context during remount/mount of
+ * the same sb, this must be the same or part of the same
+ * security options, just free it.
+ */
+ security_free_mnt_opts(sec_opts);
+ }
+#endif
+ return ret;
+}
+
+/*
+ * Find a superblock for the given device / mount point.
+ *
+ * Note: This is based on mount_bdev from fs/super.c with a few additions
+ * for multiple device setup. Make sure to keep it in sync.
+ */
+static struct dentry *btrfs_mount_root(struct file_system_type *fs_type,
+ int flags, const char *device_name, void *data)
+{
+ struct block_device *bdev = NULL;
+ struct super_block *s;
+ struct btrfs_device *device = NULL;
+ struct btrfs_fs_devices *fs_devices = NULL;
+ struct btrfs_fs_info *fs_info = NULL;
+ struct security_mnt_opts new_sec_opts;
+ fmode_t mode = FMODE_READ;
+ int error = 0;
+
+ if (!(flags & SB_RDONLY))
+ mode |= FMODE_WRITE;
+
+ security_init_mnt_opts(&new_sec_opts);
+ if (data) {
+ error = parse_security_options(data, &new_sec_opts);
+ if (error)
+ return ERR_PTR(error);
+ }
+
+ /*
+ * Setup a dummy root and fs_info for test/set super. This is because
+ * we don't actually fill this stuff out until open_ctree, but we need
+ * it for searching for existing supers, so this lets us do that and
+ * then open_ctree will properly initialize everything later.
+ */
+ fs_info = kvzalloc(sizeof(struct btrfs_fs_info), GFP_KERNEL);
+ if (!fs_info) {
+ error = -ENOMEM;
+ goto error_sec_opts;
+ }
+
+ fs_info->super_copy = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_KERNEL);
+ fs_info->super_for_commit = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_KERNEL);
+ security_init_mnt_opts(&fs_info->security_opts);
+ if (!fs_info->super_copy || !fs_info->super_for_commit) {
+ error = -ENOMEM;
+ goto error_fs_info;
+ }
+
+ mutex_lock(&uuid_mutex);
+ error = btrfs_parse_device_options(data, mode, fs_type);
+ if (error) {
+ mutex_unlock(&uuid_mutex);
+ goto error_fs_info;
+ }
+
+ device = btrfs_scan_one_device(device_name, mode, fs_type);
+ if (IS_ERR(device)) {
+ mutex_unlock(&uuid_mutex);
+ error = PTR_ERR(device);
+ goto error_fs_info;
+ }
+
+ fs_devices = device->fs_devices;
+ fs_info->fs_devices = fs_devices;
+
+ error = btrfs_open_devices(fs_devices, mode, fs_type);
+ mutex_unlock(&uuid_mutex);
+ if (error)
+ goto error_fs_info;
+
+ if (!(flags & SB_RDONLY) && fs_devices->rw_devices == 0) {
+ error = -EACCES;
+ goto error_close_devices;
+ }
+
+ bdev = fs_devices->latest_bdev;
+ s = sget(fs_type, btrfs_test_super, btrfs_set_super, flags | SB_NOSEC,
+ fs_info);
+ if (IS_ERR(s)) {
+ error = PTR_ERR(s);
+ goto error_close_devices;
+ }
+
+ if (s->s_root) {
+ btrfs_close_devices(fs_devices);
+ free_fs_info(fs_info);
+ if ((flags ^ s->s_flags) & SB_RDONLY)
+ error = -EBUSY;
+ } else {
+ snprintf(s->s_id, sizeof(s->s_id), "%pg", bdev);
+ btrfs_sb(s)->bdev_holder = fs_type;
+ error = btrfs_fill_super(s, fs_devices, data);
+ }
+ if (error) {
+ deactivate_locked_super(s);
+ goto error_sec_opts;
+ }
+
+ fs_info = btrfs_sb(s);
+ error = setup_security_options(fs_info, s, &new_sec_opts);
+ if (error) {
+ deactivate_locked_super(s);
+ goto error_sec_opts;
+ }
+
+ return dget(s->s_root);
+
+error_close_devices:
+ btrfs_close_devices(fs_devices);
+error_fs_info:
+ free_fs_info(fs_info);
+error_sec_opts:
+ security_free_mnt_opts(&new_sec_opts);
+ return ERR_PTR(error);
+}
+
+/*
+ * Mount function which is called by VFS layer.
+ *
+ * In order to allow mounting a subvolume directly, btrfs uses mount_subtree()
+ * which needs vfsmount* of device's root (/). This means device's root has to
+ * be mounted internally in any case.
+ *
+ * Operation flow:
+ * 1. Parse subvol id related options for later use in mount_subvol().
+ *
+ * 2. Mount device's root (/) by calling vfs_kern_mount().
+ *
+ * NOTE: vfs_kern_mount() is used by VFS to call btrfs_mount() in the
+ * first place. In order to avoid calling btrfs_mount() again, we use
+ * different file_system_type which is not registered to VFS by
+ * register_filesystem() (btrfs_root_fs_type). As a result,
+ * btrfs_mount_root() is called. The return value will be used by
+ * mount_subtree() in mount_subvol().
+ *
+ * 3. Call mount_subvol() to get the dentry of subvolume. Since there is
+ * "btrfs subvolume set-default", mount_subvol() is called always.
+ */
+static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags,
+ const char *device_name, void *data)
+{
+ struct vfsmount *mnt_root;
+ struct dentry *root;
+ fmode_t mode = FMODE_READ;
+ char *subvol_name = NULL;
+ u64 subvol_objectid = 0;
+ int error = 0;
+
+ if (!(flags & SB_RDONLY))
+ mode |= FMODE_WRITE;
+
+ error = btrfs_parse_subvol_options(data, &subvol_name,
+ &subvol_objectid);
+ if (error) {
+ kfree(subvol_name);
+ return ERR_PTR(error);
+ }
+
+ /* mount device's root (/) */
+ mnt_root = vfs_kern_mount(&btrfs_root_fs_type, flags, device_name, data);
+ if (PTR_ERR_OR_ZERO(mnt_root) == -EBUSY) {
+ if (flags & SB_RDONLY) {
+ mnt_root = vfs_kern_mount(&btrfs_root_fs_type,
+ flags & ~SB_RDONLY, device_name, data);
+ } else {
+ mnt_root = vfs_kern_mount(&btrfs_root_fs_type,
+ flags | SB_RDONLY, device_name, data);
+ if (IS_ERR(mnt_root)) {
+ root = ERR_CAST(mnt_root);
+ goto out;
+ }
+
+ down_write(&mnt_root->mnt_sb->s_umount);
+ error = btrfs_remount(mnt_root->mnt_sb, &flags, NULL);
+ up_write(&mnt_root->mnt_sb->s_umount);
+ if (error < 0) {
+ root = ERR_PTR(error);
+ mntput(mnt_root);
+ goto out;
+ }
+ }
+ }
+ if (IS_ERR(mnt_root)) {
+ root = ERR_CAST(mnt_root);
+ goto out;
+ }
+
+ /* mount_subvol() will free subvol_name and mnt_root */
+ root = mount_subvol(subvol_name, subvol_objectid, device_name, mnt_root);
+
+out:
+ return root;
+}
+
+static void btrfs_resize_thread_pool(struct btrfs_fs_info *fs_info,
+ u32 new_pool_size, u32 old_pool_size)
+{
+ if (new_pool_size == old_pool_size)
+ return;
+
+ fs_info->thread_pool_size = new_pool_size;
+
+ btrfs_info(fs_info, "resize thread pool %d -> %d",
+ old_pool_size, new_pool_size);
+
+ btrfs_workqueue_set_max(fs_info->workers, new_pool_size);
+ btrfs_workqueue_set_max(fs_info->delalloc_workers, new_pool_size);
+ btrfs_workqueue_set_max(fs_info->submit_workers, new_pool_size);
+ btrfs_workqueue_set_max(fs_info->caching_workers, new_pool_size);
+ btrfs_workqueue_set_max(fs_info->endio_workers, new_pool_size);
+ btrfs_workqueue_set_max(fs_info->endio_meta_workers, new_pool_size);
+ btrfs_workqueue_set_max(fs_info->endio_meta_write_workers,
+ new_pool_size);
+ btrfs_workqueue_set_max(fs_info->endio_write_workers, new_pool_size);
+ btrfs_workqueue_set_max(fs_info->endio_freespace_worker, new_pool_size);
+ btrfs_workqueue_set_max(fs_info->delayed_workers, new_pool_size);
+ btrfs_workqueue_set_max(fs_info->readahead_workers, new_pool_size);
+ btrfs_workqueue_set_max(fs_info->scrub_wr_completion_workers,
+ new_pool_size);
+}
+
+static inline void btrfs_remount_prepare(struct btrfs_fs_info *fs_info)
+{
+ set_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
+}
+
+static inline void btrfs_remount_begin(struct btrfs_fs_info *fs_info,
+ unsigned long old_opts, int flags)
+{
+ if (btrfs_raw_test_opt(old_opts, AUTO_DEFRAG) &&
+ (!btrfs_raw_test_opt(fs_info->mount_opt, AUTO_DEFRAG) ||
+ (flags & SB_RDONLY))) {
+ /* wait for any defraggers to finish */
+ wait_event(fs_info->transaction_wait,
+ (atomic_read(&fs_info->defrag_running) == 0));
+ if (flags & SB_RDONLY)
+ sync_filesystem(fs_info->sb);
+ }
+}
+
+static inline void btrfs_remount_cleanup(struct btrfs_fs_info *fs_info,
+ unsigned long old_opts)
+{
+ /*
+ * We need to cleanup all defragable inodes if the autodefragment is
+ * close or the filesystem is read only.
+ */
+ if (btrfs_raw_test_opt(old_opts, AUTO_DEFRAG) &&
+ (!btrfs_raw_test_opt(fs_info->mount_opt, AUTO_DEFRAG) || sb_rdonly(fs_info->sb))) {
+ btrfs_cleanup_defrag_inodes(fs_info);
+ }
+
+ clear_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
+}
+
+static int btrfs_remount(struct super_block *sb, int *flags, char *data)
+{
+ struct btrfs_fs_info *fs_info = btrfs_sb(sb);
+ struct btrfs_root *root = fs_info->tree_root;
+ unsigned old_flags = sb->s_flags;
+ unsigned long old_opts = fs_info->mount_opt;
+ unsigned long old_compress_type = fs_info->compress_type;
+ u64 old_max_inline = fs_info->max_inline;
+ u32 old_thread_pool_size = fs_info->thread_pool_size;
+ u32 old_metadata_ratio = fs_info->metadata_ratio;
+ int ret;
+
+ sync_filesystem(sb);
+ btrfs_remount_prepare(fs_info);
+
+ if (data) {
+ struct security_mnt_opts new_sec_opts;
+
+ security_init_mnt_opts(&new_sec_opts);
+ ret = parse_security_options(data, &new_sec_opts);
+ if (ret)
+ goto restore;
+ ret = setup_security_options(fs_info, sb,
+ &new_sec_opts);
+ if (ret) {
+ security_free_mnt_opts(&new_sec_opts);
+ goto restore;
+ }
+ }
+
+ ret = btrfs_parse_options(fs_info, data, *flags);
+ if (ret)
+ goto restore;
+
+ btrfs_remount_begin(fs_info, old_opts, *flags);
+ btrfs_resize_thread_pool(fs_info,
+ fs_info->thread_pool_size, old_thread_pool_size);
+
+ if ((bool)(*flags & SB_RDONLY) == sb_rdonly(sb))
+ goto out;
+
+ if (*flags & SB_RDONLY) {
+ /*
+ * this also happens on 'umount -rf' or on shutdown, when
+ * the filesystem is busy.
+ */
+ cancel_work_sync(&fs_info->async_reclaim_work);
+
+ /* wait for the uuid_scan task to finish */
+ down(&fs_info->uuid_tree_rescan_sem);
+ /* avoid complains from lockdep et al. */
+ up(&fs_info->uuid_tree_rescan_sem);
+
+ sb->s_flags |= SB_RDONLY;
+
+ /*
+ * Setting SB_RDONLY will put the cleaner thread to
+ * sleep at the next loop if it's already active.
+ * If it's already asleep, we'll leave unused block
+ * groups on disk until we're mounted read-write again
+ * unless we clean them up here.
+ */
+ btrfs_delete_unused_bgs(fs_info);
+
+ btrfs_dev_replace_suspend_for_unmount(fs_info);
+ btrfs_scrub_cancel(fs_info);
+ btrfs_pause_balance(fs_info);
+
+ ret = btrfs_commit_super(fs_info);
+ if (ret)
+ goto restore;
+ } else {
+ if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state)) {
+ btrfs_err(fs_info,
+ "Remounting read-write after error is not allowed");
+ ret = -EINVAL;
+ goto restore;
+ }
+ if (fs_info->fs_devices->rw_devices == 0) {
+ ret = -EACCES;
+ goto restore;
+ }
+
+ if (!btrfs_check_rw_degradable(fs_info, NULL)) {
+ btrfs_warn(fs_info,
+ "too many missing devices, writeable remount is not allowed");
+ ret = -EACCES;
+ goto restore;
+ }
+
+ if (btrfs_super_log_root(fs_info->super_copy) != 0) {
+ ret = -EINVAL;
+ goto restore;
+ }
+
+ ret = btrfs_cleanup_fs_roots(fs_info);
+ if (ret)
+ goto restore;
+
+ /* recover relocation */
+ mutex_lock(&fs_info->cleaner_mutex);
+ ret = btrfs_recover_relocation(root);
+ mutex_unlock(&fs_info->cleaner_mutex);
+ if (ret)
+ goto restore;
+
+ ret = btrfs_resume_balance_async(fs_info);
+ if (ret)
+ goto restore;
+
+ ret = btrfs_resume_dev_replace_async(fs_info);
+ if (ret) {
+ btrfs_warn(fs_info, "failed to resume dev_replace");
+ goto restore;
+ }
+
+ btrfs_qgroup_rescan_resume(fs_info);
+
+ if (!fs_info->uuid_root) {
+ btrfs_info(fs_info, "creating UUID tree");
+ ret = btrfs_create_uuid_tree(fs_info);
+ if (ret) {
+ btrfs_warn(fs_info,
+ "failed to create the UUID tree %d",
+ ret);
+ goto restore;
+ }
+ }
+ sb->s_flags &= ~SB_RDONLY;
+
+ set_bit(BTRFS_FS_OPEN, &fs_info->flags);
+ }
+out:
+ wake_up_process(fs_info->transaction_kthread);
+ btrfs_remount_cleanup(fs_info, old_opts);
+ return 0;
+
+restore:
+ /* We've hit an error - don't reset SB_RDONLY */
+ if (sb_rdonly(sb))
+ old_flags |= SB_RDONLY;
+ sb->s_flags = old_flags;
+ fs_info->mount_opt = old_opts;
+ fs_info->compress_type = old_compress_type;
+ fs_info->max_inline = old_max_inline;
+ btrfs_resize_thread_pool(fs_info,
+ old_thread_pool_size, fs_info->thread_pool_size);
+ fs_info->metadata_ratio = old_metadata_ratio;
+ btrfs_remount_cleanup(fs_info, old_opts);
+ return ret;
+}
+
+/* Used to sort the devices by max_avail(descending sort) */
+static int btrfs_cmp_device_free_bytes(const void *dev_info1,
+ const void *dev_info2)
+{
+ if (((struct btrfs_device_info *)dev_info1)->max_avail >
+ ((struct btrfs_device_info *)dev_info2)->max_avail)
+ return -1;
+ else if (((struct btrfs_device_info *)dev_info1)->max_avail <
+ ((struct btrfs_device_info *)dev_info2)->max_avail)
+ return 1;
+ else
+ return 0;
+}
+
+/*
+ * sort the devices by max_avail, in which max free extent size of each device
+ * is stored.(Descending Sort)
+ */
+static inline void btrfs_descending_sort_devices(
+ struct btrfs_device_info *devices,
+ size_t nr_devices)
+{
+ sort(devices, nr_devices, sizeof(struct btrfs_device_info),
+ btrfs_cmp_device_free_bytes, NULL);
+}
+
+/*
+ * The helper to calc the free space on the devices that can be used to store
+ * file data.
+ */
+static int btrfs_calc_avail_data_space(struct btrfs_fs_info *fs_info,
+ u64 *free_bytes)
+{
+ struct btrfs_device_info *devices_info;
+ struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
+ struct btrfs_device *device;
+ u64 skip_space;
+ u64 type;
+ u64 avail_space;
+ u64 min_stripe_size;
+ int min_stripes = 1, num_stripes = 1;
+ int i = 0, nr_devices;
+
+ /*
+ * We aren't under the device list lock, so this is racy-ish, but good
+ * enough for our purposes.
+ */
+ nr_devices = fs_info->fs_devices->open_devices;
+ if (!nr_devices) {
+ smp_mb();
+ nr_devices = fs_info->fs_devices->open_devices;
+ ASSERT(nr_devices);
+ if (!nr_devices) {
+ *free_bytes = 0;
+ return 0;
+ }
+ }
+
+ devices_info = kmalloc_array(nr_devices, sizeof(*devices_info),
+ GFP_KERNEL);
+ if (!devices_info)
+ return -ENOMEM;
+
+ /* calc min stripe number for data space allocation */
+ type = btrfs_data_alloc_profile(fs_info);
+ if (type & BTRFS_BLOCK_GROUP_RAID0) {
+ min_stripes = 2;
+ num_stripes = nr_devices;
+ } else if (type & BTRFS_BLOCK_GROUP_RAID1) {
+ min_stripes = 2;
+ num_stripes = 2;
+ } else if (type & BTRFS_BLOCK_GROUP_RAID10) {
+ min_stripes = 4;
+ num_stripes = 4;
+ }
+
+ if (type & BTRFS_BLOCK_GROUP_DUP)
+ min_stripe_size = 2 * BTRFS_STRIPE_LEN;
+ else
+ min_stripe_size = BTRFS_STRIPE_LEN;
+
+ rcu_read_lock();
+ list_for_each_entry_rcu(device, &fs_devices->devices, dev_list) {
+ if (!test_bit(BTRFS_DEV_STATE_IN_FS_METADATA,
+ &device->dev_state) ||
+ !device->bdev ||
+ test_bit(BTRFS_DEV_STATE_REPLACE_TGT, &device->dev_state))
+ continue;
+
+ if (i >= nr_devices)
+ break;
+
+ avail_space = device->total_bytes - device->bytes_used;
+
+ /* align with stripe_len */
+ avail_space = div_u64(avail_space, BTRFS_STRIPE_LEN);
+ avail_space *= BTRFS_STRIPE_LEN;
+
+ /*
+ * In order to avoid overwriting the superblock on the drive,
+ * btrfs starts at an offset of at least 1MB when doing chunk
+ * allocation.
+ */
+ skip_space = SZ_1M;
+
+ /*
+ * we can use the free space in [0, skip_space - 1], subtract
+ * it from the total.
+ */
+ if (avail_space && avail_space >= skip_space)
+ avail_space -= skip_space;
+ else
+ avail_space = 0;
+
+ if (avail_space < min_stripe_size)
+ continue;
+
+ devices_info[i].dev = device;
+ devices_info[i].max_avail = avail_space;
+
+ i++;
+ }
+ rcu_read_unlock();
+
+ nr_devices = i;
+
+ btrfs_descending_sort_devices(devices_info, nr_devices);
+
+ i = nr_devices - 1;
+ avail_space = 0;
+ while (nr_devices >= min_stripes) {
+ if (num_stripes > nr_devices)
+ num_stripes = nr_devices;
+
+ if (devices_info[i].max_avail >= min_stripe_size) {
+ int j;
+ u64 alloc_size;
+
+ avail_space += devices_info[i].max_avail * num_stripes;
+ alloc_size = devices_info[i].max_avail;
+ for (j = i + 1 - num_stripes; j <= i; j++)
+ devices_info[j].max_avail -= alloc_size;
+ }
+ i--;
+ nr_devices--;
+ }
+
+ kfree(devices_info);
+ *free_bytes = avail_space;
+ return 0;
+}
+
+/*
+ * Calculate numbers for 'df', pessimistic in case of mixed raid profiles.
+ *
+ * If there's a redundant raid level at DATA block groups, use the respective
+ * multiplier to scale the sizes.
+ *
+ * Unused device space usage is based on simulating the chunk allocator
+ * algorithm that respects the device sizes and order of allocations. This is
+ * a close approximation of the actual use but there are other factors that may
+ * change the result (like a new metadata chunk).
+ *
+ * If metadata is exhausted, f_bavail will be 0.
+ */
+static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf)
+{
+ struct btrfs_fs_info *fs_info = btrfs_sb(dentry->d_sb);
+ struct btrfs_super_block *disk_super = fs_info->super_copy;
+ struct list_head *head = &fs_info->space_info;
+ struct btrfs_space_info *found;
+ u64 total_used = 0;
+ u64 total_free_data = 0;
+ u64 total_free_meta = 0;
+ int bits = dentry->d_sb->s_blocksize_bits;
+ __be32 *fsid = (__be32 *)fs_info->fsid;
+ unsigned factor = 1;
+ struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
+ int ret;
+ u64 thresh = 0;
+ int mixed = 0;
+
+ rcu_read_lock();
+ list_for_each_entry_rcu(found, head, list) {
+ if (found->flags & BTRFS_BLOCK_GROUP_DATA) {
+ int i;
+
+ total_free_data += found->disk_total - found->disk_used;
+ total_free_data -=
+ btrfs_account_ro_block_groups_free_space(found);
+
+ for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) {
+ if (!list_empty(&found->block_groups[i]))
+ factor = btrfs_bg_type_to_factor(
+ btrfs_raid_array[i].bg_flag);
+ }
+ }
+
+ /*
+ * Metadata in mixed block goup profiles are accounted in data
+ */
+ if (!mixed && found->flags & BTRFS_BLOCK_GROUP_METADATA) {
+ if (found->flags & BTRFS_BLOCK_GROUP_DATA)
+ mixed = 1;
+ else
+ total_free_meta += found->disk_total -
+ found->disk_used;
+ }
+
+ total_used += found->disk_used;
+ }
+
+ rcu_read_unlock();
+
+ buf->f_blocks = div_u64(btrfs_super_total_bytes(disk_super), factor);
+ buf->f_blocks >>= bits;
+ buf->f_bfree = buf->f_blocks - (div_u64(total_used, factor) >> bits);
+
+ /* Account global block reserve as used, it's in logical size already */
+ spin_lock(&block_rsv->lock);
+ /* Mixed block groups accounting is not byte-accurate, avoid overflow */
+ if (buf->f_bfree >= block_rsv->size >> bits)
+ buf->f_bfree -= block_rsv->size >> bits;
+ else
+ buf->f_bfree = 0;
+ spin_unlock(&block_rsv->lock);
+
+ buf->f_bavail = div_u64(total_free_data, factor);
+ ret = btrfs_calc_avail_data_space(fs_info, &total_free_data);
+ if (ret)
+ return ret;
+ buf->f_bavail += div_u64(total_free_data, factor);
+ buf->f_bavail = buf->f_bavail >> bits;
+
+ /*
+ * We calculate the remaining metadata space minus global reserve. If
+ * this is (supposedly) smaller than zero, there's no space. But this
+ * does not hold in practice, the exhausted state happens where's still
+ * some positive delta. So we apply some guesswork and compare the
+ * delta to a 4M threshold. (Practically observed delta was ~2M.)
+ *
+ * We probably cannot calculate the exact threshold value because this
+ * depends on the internal reservations requested by various
+ * operations, so some operations that consume a few metadata will
+ * succeed even if the Avail is zero. But this is better than the other
+ * way around.
+ */
+ thresh = SZ_4M;
+
+ if (!mixed && total_free_meta - thresh < block_rsv->size)
+ buf->f_bavail = 0;
+
+ buf->f_type = BTRFS_SUPER_MAGIC;
+ buf->f_bsize = dentry->d_sb->s_blocksize;
+ buf->f_namelen = BTRFS_NAME_LEN;
+
+ /* We treat it as constant endianness (it doesn't matter _which_)
+ because we want the fsid to come out the same whether mounted
+ on a big-endian or little-endian host */
+ buf->f_fsid.val[0] = be32_to_cpu(fsid[0]) ^ be32_to_cpu(fsid[2]);
+ buf->f_fsid.val[1] = be32_to_cpu(fsid[1]) ^ be32_to_cpu(fsid[3]);
+ /* Mask in the root object ID too, to disambiguate subvols */
+ buf->f_fsid.val[0] ^= BTRFS_I(d_inode(dentry))->root->objectid >> 32;
+ buf->f_fsid.val[1] ^= BTRFS_I(d_inode(dentry))->root->objectid;
+
+ return 0;
+}
+
+static void btrfs_kill_super(struct super_block *sb)
+{
+ struct btrfs_fs_info *fs_info = btrfs_sb(sb);
+ kill_anon_super(sb);
+ free_fs_info(fs_info);
+}
+
+static struct file_system_type btrfs_fs_type = {
+ .owner = THIS_MODULE,
+ .name = "btrfs",
+ .mount = btrfs_mount,
+ .kill_sb = btrfs_kill_super,
+ .fs_flags = FS_REQUIRES_DEV | FS_BINARY_MOUNTDATA,
+};
+
+static struct file_system_type btrfs_root_fs_type = {
+ .owner = THIS_MODULE,
+ .name = "btrfs",
+ .mount = btrfs_mount_root,
+ .kill_sb = btrfs_kill_super,
+ .fs_flags = FS_REQUIRES_DEV | FS_BINARY_MOUNTDATA,
+};
+
+MODULE_ALIAS_FS("btrfs");
+
+static int btrfs_control_open(struct inode *inode, struct file *file)
+{
+ /*
+ * The control file's private_data is used to hold the
+ * transaction when it is started and is used to keep
+ * track of whether a transaction is already in progress.
+ */
+ file->private_data = NULL;
+ return 0;
+}
+
+/*
+ * used by btrfsctl to scan devices when no FS is mounted
+ */
+static long btrfs_control_ioctl(struct file *file, unsigned int cmd,
+ unsigned long arg)
+{
+ struct btrfs_ioctl_vol_args *vol;
+ struct btrfs_device *device = NULL;
+ int ret = -ENOTTY;
+
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
+
+ vol = memdup_user((void __user *)arg, sizeof(*vol));
+ if (IS_ERR(vol))
+ return PTR_ERR(vol);
+ vol->name[BTRFS_PATH_NAME_MAX] = '\0';
+
+ switch (cmd) {
+ case BTRFS_IOC_SCAN_DEV:
+ mutex_lock(&uuid_mutex);
+ device = btrfs_scan_one_device(vol->name, FMODE_READ,
+ &btrfs_root_fs_type);
+ ret = PTR_ERR_OR_ZERO(device);
+ mutex_unlock(&uuid_mutex);
+ break;
+ case BTRFS_IOC_DEVICES_READY:
+ mutex_lock(&uuid_mutex);
+ device = btrfs_scan_one_device(vol->name, FMODE_READ,
+ &btrfs_root_fs_type);
+ if (IS_ERR(device)) {
+ mutex_unlock(&uuid_mutex);
+ ret = PTR_ERR(device);
+ break;
+ }
+ ret = !(device->fs_devices->num_devices ==
+ device->fs_devices->total_devices);
+ mutex_unlock(&uuid_mutex);
+ break;
+ case BTRFS_IOC_GET_SUPPORTED_FEATURES:
+ ret = btrfs_ioctl_get_supported_features((void __user*)arg);
+ break;
+ }
+
+ kfree(vol);
+ return ret;
+}
+
+static int btrfs_freeze(struct super_block *sb)
+{
+ struct btrfs_trans_handle *trans;
+ struct btrfs_fs_info *fs_info = btrfs_sb(sb);
+ struct btrfs_root *root = fs_info->tree_root;
+
+ set_bit(BTRFS_FS_FROZEN, &fs_info->flags);
+ /*
+ * We don't need a barrier here, we'll wait for any transaction that
+ * could be in progress on other threads (and do delayed iputs that
+ * we want to avoid on a frozen filesystem), or do the commit
+ * ourselves.
+ */
+ trans = btrfs_attach_transaction_barrier(root);
+ if (IS_ERR(trans)) {
+ /* no transaction, don't bother */
+ if (PTR_ERR(trans) == -ENOENT)
+ return 0;
+ return PTR_ERR(trans);
+ }
+ return btrfs_commit_transaction(trans);
+}
+
+static int btrfs_unfreeze(struct super_block *sb)
+{
+ struct btrfs_fs_info *fs_info = btrfs_sb(sb);
+
+ clear_bit(BTRFS_FS_FROZEN, &fs_info->flags);
+ return 0;
+}
+
+static int btrfs_show_devname(struct seq_file *m, struct dentry *root)
+{
+ struct btrfs_fs_info *fs_info = btrfs_sb(root->d_sb);
+ struct btrfs_fs_devices *cur_devices;
+ struct btrfs_device *dev, *first_dev = NULL;
+ struct list_head *head;
+
+ /*
+ * Lightweight locking of the devices. We should not need
+ * device_list_mutex here as we only read the device data and the list
+ * is protected by RCU. Even if a device is deleted during the list
+ * traversals, we'll get valid data, the freeing callback will wait at
+ * least until until the rcu_read_unlock.
+ */
+ rcu_read_lock();
+ cur_devices = fs_info->fs_devices;
+ while (cur_devices) {
+ head = &cur_devices->devices;
+ list_for_each_entry_rcu(dev, head, dev_list) {
+ if (test_bit(BTRFS_DEV_STATE_MISSING, &dev->dev_state))
+ continue;
+ if (!dev->name)
+ continue;
+ if (!first_dev || dev->devid < first_dev->devid)
+ first_dev = dev;
+ }
+ cur_devices = cur_devices->seed;
+ }
+
+ if (first_dev)
+ seq_escape(m, rcu_str_deref(first_dev->name), " \t\n\\");
+ else
+ WARN_ON(1);
+ rcu_read_unlock();
+ return 0;
+}
+
+static const struct super_operations btrfs_super_ops = {
+ .drop_inode = btrfs_drop_inode,
+ .evict_inode = btrfs_evict_inode,
+ .put_super = btrfs_put_super,
+ .sync_fs = btrfs_sync_fs,
+ .show_options = btrfs_show_options,
+ .show_devname = btrfs_show_devname,
+ .alloc_inode = btrfs_alloc_inode,
+ .destroy_inode = btrfs_destroy_inode,
+ .statfs = btrfs_statfs,
+ .remount_fs = btrfs_remount,
+ .freeze_fs = btrfs_freeze,
+ .unfreeze_fs = btrfs_unfreeze,
+};
+
+static const struct file_operations btrfs_ctl_fops = {
+ .open = btrfs_control_open,
+ .unlocked_ioctl = btrfs_control_ioctl,
+ .compat_ioctl = btrfs_control_ioctl,
+ .owner = THIS_MODULE,
+ .llseek = noop_llseek,
+};
+
+static struct miscdevice btrfs_misc = {
+ .minor = BTRFS_MINOR,
+ .name = "btrfs-control",
+ .fops = &btrfs_ctl_fops
+};
+
+MODULE_ALIAS_MISCDEV(BTRFS_MINOR);
+MODULE_ALIAS("devname:btrfs-control");
+
+static int __init btrfs_interface_init(void)
+{
+ return misc_register(&btrfs_misc);
+}
+
+static __cold void btrfs_interface_exit(void)
+{
+ misc_deregister(&btrfs_misc);
+}
+
+static void __init btrfs_print_mod_info(void)
+{
+ static const char options[] = ""
+#ifdef CONFIG_BTRFS_DEBUG
+ ", debug=on"
+#endif
+#ifdef CONFIG_BTRFS_ASSERT
+ ", assert=on"
+#endif
+#ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
+ ", integrity-checker=on"
+#endif
+#ifdef CONFIG_BTRFS_FS_REF_VERIFY
+ ", ref-verify=on"
+#endif
+ ;
+ pr_info("Btrfs loaded, crc32c=%s%s\n", crc32c_impl(), options);
+}
+
+static int __init init_btrfs_fs(void)
+{
+ int err;
+
+ btrfs_props_init();
+
+ err = btrfs_init_sysfs();
+ if (err)
+ return err;
+
+ btrfs_init_compress();
+
+ err = btrfs_init_cachep();
+ if (err)
+ goto free_compress;
+
+ err = extent_io_init();
+ if (err)
+ goto free_cachep;
+
+ err = extent_map_init();
+ if (err)
+ goto free_extent_io;
+
+ err = ordered_data_init();
+ if (err)
+ goto free_extent_map;
+
+ err = btrfs_delayed_inode_init();
+ if (err)
+ goto free_ordered_data;
+
+ err = btrfs_auto_defrag_init();
+ if (err)
+ goto free_delayed_inode;
+
+ err = btrfs_delayed_ref_init();
+ if (err)
+ goto free_auto_defrag;
+
+ err = btrfs_prelim_ref_init();
+ if (err)
+ goto free_delayed_ref;
+
+ err = btrfs_end_io_wq_init();
+ if (err)
+ goto free_prelim_ref;
+
+ err = btrfs_interface_init();
+ if (err)
+ goto free_end_io_wq;
+
+ btrfs_init_lockdep();
+
+ btrfs_print_mod_info();
+
+ err = btrfs_run_sanity_tests();
+ if (err)
+ goto unregister_ioctl;
+
+ err = register_filesystem(&btrfs_fs_type);
+ if (err)
+ goto unregister_ioctl;
+
+ return 0;
+
+unregister_ioctl:
+ btrfs_interface_exit();
+free_end_io_wq:
+ btrfs_end_io_wq_exit();
+free_prelim_ref:
+ btrfs_prelim_ref_exit();
+free_delayed_ref:
+ btrfs_delayed_ref_exit();
+free_auto_defrag:
+ btrfs_auto_defrag_exit();
+free_delayed_inode:
+ btrfs_delayed_inode_exit();
+free_ordered_data:
+ ordered_data_exit();
+free_extent_map:
+ extent_map_exit();
+free_extent_io:
+ extent_io_exit();
+free_cachep:
+ btrfs_destroy_cachep();
+free_compress:
+ btrfs_exit_compress();
+ btrfs_exit_sysfs();
+
+ return err;
+}
+
+static void __exit exit_btrfs_fs(void)
+{
+ btrfs_destroy_cachep();
+ btrfs_delayed_ref_exit();
+ btrfs_auto_defrag_exit();
+ btrfs_delayed_inode_exit();
+ btrfs_prelim_ref_exit();
+ ordered_data_exit();
+ extent_map_exit();
+ extent_io_exit();
+ btrfs_interface_exit();
+ btrfs_end_io_wq_exit();
+ unregister_filesystem(&btrfs_fs_type);
+ btrfs_exit_sysfs();
+ btrfs_cleanup_fs_uuids();
+ btrfs_exit_compress();
+}
+
+late_initcall(init_btrfs_fs);
+module_exit(exit_btrfs_fs)
+
+MODULE_LICENSE("GPL");