Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/fs/fat/inode.c b/fs/fat/inode.c
index d6b81e3..5f04c5c 100644
--- a/fs/fat/inode.c
+++ b/fs/fat/inode.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  *  linux/fs/fat/inode.c
  *
@@ -30,6 +31,11 @@
 
 #define KB_IN_SECTORS 2
 
+/* DOS dates from 1980/1/1 through 2107/12/31 */
+#define FAT_DATE_MIN (0<<9 | 1<<5 | 1)
+#define FAT_DATE_MAX (127<<9 | 12<<5 | 31)
+#define FAT_TIME_MAX (23<<11 | 59<<5 | 29)
+
 /*
  * A deserialized copy of the on-disk structure laid out in struct
  * fat_boot_sector.
@@ -244,7 +250,7 @@
 	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);
+		fat_truncate_time(inode, NULL, S_CTIME|S_MTIME);
 		MSDOS_I(inode)->i_attrs |= ATTR_ARCH;
 		mark_inode_dirty(inode);
 	}
@@ -564,7 +570,7 @@
 				  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;
+		fat_truncate_time(inode, &inode->i_mtime, S_ATIME|S_CTIME);
 
 	return 0;
 }
@@ -686,7 +692,7 @@
 
 	b = (struct fat_boot_sector *) bh->b_data;
 
-	if (sbi->fat_bits == 32) {
+	if (is_fat32(sbi)) {
 		if (set)
 			b->fat32.state |= FAT_STATE_DIRTY;
 		else
@@ -746,17 +752,11 @@
 	return &ei->vfs_inode;
 }
 
-static void fat_i_callback(struct rcu_head *head)
+static void fat_free_inode(struct inode *inode)
 {
-	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;
@@ -920,7 +920,7 @@
 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,
+	.free_inode	= fat_free_inode,
 	.write_inode	= fat_write_inode,
 	.evict_inode	= fat_evict_inode,
 	.put_super	= fat_put_super,
@@ -1396,7 +1396,7 @@
 	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) {
+	if (is_fat32(sbi)) {
 		MSDOS_I(inode)->i_start = sbi->root_cluster;
 		error = fat_calc_dir_size(inode);
 		if (error < 0)
@@ -1423,7 +1423,7 @@
 	struct msdos_sb_info *sbi = MSDOS_SB(sb);
 
 	/* Divide first to avoid overflow */
-	if (sbi->fat_bits != 12) {
+	if (!is_fat12(sbi)) {
 		unsigned long ent_per_sec = sb->s_blocksize * 8 / sbi->fat_bits;
 		return ent_per_sec * sbi->fat_length;
 	}
@@ -1610,6 +1610,7 @@
 	int debug;
 	long error;
 	char buf[50];
+	struct timespec64 ts;
 
 	/*
 	 * GFP_KERNEL is ok here, because while we do hold the
@@ -1626,6 +1627,11 @@
 	sb->s_magic = MSDOS_SUPER_MAGIC;
 	sb->s_op = &fat_sops;
 	sb->s_export_op = &fat_export_ops;
+	/*
+	 * fat timestamps are complex and truncated by fat itself, so
+	 * we set 1 here to be fast
+	 */
+	sb->s_time_gran = 1;
 	mutex_init(&sbi->nfs_build_inode_lock);
 	ratelimit_state_init(&sbi->ratelimit, DEFAULT_RATELIMIT_INTERVAL,
 			     DEFAULT_RATELIMIT_BURST);
@@ -1698,6 +1704,12 @@
 	sbi->free_clus_valid = 0;
 	sbi->prev_free = FAT_START_ENT;
 	sb->s_maxbytes = 0xffffffff;
+	fat_time_fat2unix(sbi, &ts, 0, cpu_to_le16(FAT_DATE_MIN), 0);
+	sb->s_time_min = ts.tv_sec;
+
+	fat_time_fat2unix(sbi, &ts, cpu_to_le16(FAT_TIME_MAX),
+			  cpu_to_le16(FAT_DATE_MAX), 0);
+	sb->s_time_max = ts.tv_sec;
 
 	if (!sbi->fat_length && bpb.fat32_length) {
 		struct fat_boot_fsinfo *fsinfo;
@@ -1738,7 +1750,7 @@
 	}
 
 	/* interpret volume ID as a little endian 32 bit integer */
-	if (sbi->fat_bits == 32)
+	if (is_fat32(sbi))
 		sbi->vol_id = bpb.fat32_vol_id;
 	else /* fat 16 or 12 */
 		sbi->vol_id = bpb.fat16_vol_id;
@@ -1764,11 +1776,11 @@
 
 	total_clusters = (total_sectors - sbi->data_start) / sbi->sec_per_clus;
 
-	if (sbi->fat_bits != 32)
+	if (!is_fat32(sbi))
 		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)
+	if (is_fat32(sbi))
 		sbi->dirty = bpb.fat32_state & FAT_STATE_DIRTY;
 	else /* fat 16 or 12 */
 		sbi->dirty = bpb.fat16_state & FAT_STATE_DIRTY;
@@ -1776,7 +1788,7 @@
 	/* 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 (total_clusters > max_fat(sb)) {
 		if (!silent)
 			fat_msg(sb, KERN_ERR, "count of clusters too big (%u)",
 			       total_clusters);
@@ -1798,11 +1810,15 @@
 	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.
+	 * The low byte of the first FAT entry must have the same value as
+	 * the media field of the boot sector. But in real world, too many
+	 * devices are writing wrong values. So, removed that validity check.
 	 *
-	 * if (FAT_FIRST_ENT(sb, media) != first)
+	 * The removed check compared the first FAT entry to a value dependent
+	 * on the media field like this:
+	 * == (0x0F00 | media), for FAT12
+	 * == (0XFF00 | media), for FAT16
+	 * == (0x0FFFFF | media), for FAT32
 	 */
 
 	error = -EINVAL;