fat: mmu_private race fix
mmu_private is 64bits value, hence it's not atomic to update.
So, the access rule for mmu_private is we must hold ->i_mutex. But,
fat_get_block() path doesn't follow the rule on non-allocation path.
This fixes by using i_size instead if non-allocation path.
Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/fat/fat.h b/fs/fat/fat.h
index a69f7f9..4efc503 100644
--- a/fs/fat/fat.h
+++ b/fs/fat/fat.h
@@ -91,7 +91,9 @@
/* for avoiding the race between fat_free() and fat_get_cluster() */
unsigned int cache_valid_id;
- loff_t mmu_private;
+ /* 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 */
@@ -222,7 +224,7 @@
extern int fat_get_cluster(struct inode *inode, int cluster,
int *fclus, int *dclus);
extern int fat_bmap(struct inode *inode, sector_t sector, sector_t *phys,
- unsigned long *mapped_blocks);
+ unsigned long *mapped_blocks, int create);
/* fat/dir.c */
extern const struct file_operations fat_dir_operations;