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-rw-r--r--fs/fat/fat.h2
-rw-r--r--fs/fat/inode.c66
-rw-r--r--include/uapi/linux/msdos_fs.h2
3 files changed, 70 insertions, 0 deletions
diff --git a/fs/fat/fat.h b/fs/fat/fat.h
index 12701a567752..e9cc3f0d58e2 100644
--- a/fs/fat/fat.h
+++ b/fs/fat/fat.h
@@ -95,6 +95,8 @@ struct msdos_sb_info {
spinlock_t dir_hash_lock;
struct hlist_head dir_hashtable[FAT_HASH_SIZE];
+
+ unsigned int dirty; /* fs state before mount */
};
#define FAT_CACHE_VALID 0 /* special case for valid cache */
diff --git a/fs/fat/inode.c b/fs/fat/inode.c
index 4b4d4ef910f3..780e20806346 100644
--- a/fs/fat/inode.c
+++ b/fs/fat/inode.c
@@ -488,10 +488,59 @@ static void fat_evict_inode(struct 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 = sb->s_fs_info;
+
+ /* do not change any thing if mounted read only */
+ if ((sb->s_flags & MS_RDONLY) && !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_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);
@@ -566,8 +615,18 @@ static void __exit fat_destroy_inodecache(void)
static int fat_remount(struct super_block *sb, int *flags, char *data)
{
+ int new_rdonly;
struct msdos_sb_info *sbi = MSDOS_SB(sb);
*flags |= MS_NODIRATIME | (sbi->options.isvfat ? 0 : MS_NOATIME);
+
+ /* make sure we update state on remount. */
+ new_rdonly = *flags & MS_RDONLY;
+ if (new_rdonly != (sb->s_flags & MS_RDONLY)) {
+ if (new_rdonly)
+ fat_set_state(sb, 0, 0);
+ else
+ fat_set_state(sb, 1, 1);
+ }
return 0;
}
@@ -1362,6 +1421,12 @@ int fat_fill_super(struct super_block *sb, void *data, int silent, int isvfat,
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 = b->fat32.state & FAT_STATE_DIRTY;
+ else /* fat 16 or 12 */
+ sbi->dirty = b->fat16.state & FAT_STATE_DIRTY;
+
/* check that FAT table does not overflow */
fat_clusters = sbi->fat_length * sb->s_blocksize * 8 / sbi->fat_bits;
total_clusters = min(total_clusters, fat_clusters - FAT_START_ENT);
@@ -1456,6 +1521,7 @@ int fat_fill_super(struct super_block *sb, void *data, int silent, int isvfat,
"the device does not support discard");
}
+ fat_set_state(sb, 1, 0);
return 0;
out_invalid:
diff --git a/include/uapi/linux/msdos_fs.h b/include/uapi/linux/msdos_fs.h
index b9f12450efe8..f055e58b3147 100644
--- a/include/uapi/linux/msdos_fs.h
+++ b/include/uapi/linux/msdos_fs.h
@@ -87,6 +87,8 @@
#define IS_FSINFO(x) (le32_to_cpu((x)->signature1) == FAT_FSINFO_SIG1 \
&& le32_to_cpu((x)->signature2) == FAT_FSINFO_SIG2)
+#define FAT_STATE_DIRTY 0x01
+
struct __fat_dirent {
long d_ino;
__kernel_off_t d_off;