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-rw-r--r--fs/fat/cache.c23
1 files changed, 18 insertions, 5 deletions
diff --git a/fs/fat/cache.c b/fs/fat/cache.c
index 589edde9053c..b42602298087 100644
--- a/fs/fat/cache.c
+++ b/fs/fat/cache.c
@@ -293,10 +293,12 @@ static int fat_bmap_cluster(struct inode *inode, int cluster)
}
int fat_bmap(struct inode *inode, sector_t sector, sector_t *phys,
- unsigned long *mapped_blocks)
+ unsigned long *mapped_blocks, int create)
{
struct super_block *sb = inode->i_sb;
struct msdos_sb_info *sbi = MSDOS_SB(sb);
+ const unsigned long blocksize = sb->s_blocksize;
+ const unsigned char blocksize_bits = sb->s_blocksize_bits;
sector_t last_block;
int cluster, offset;
@@ -309,10 +311,21 @@ int fat_bmap(struct inode *inode, sector_t sector, sector_t *phys,
}
return 0;
}
- last_block = (MSDOS_I(inode)->mmu_private + (sb->s_blocksize - 1))
- >> sb->s_blocksize_bits;
- if (sector >= last_block)
- return 0;
+
+ last_block = (i_size_read(inode) + (blocksize - 1)) >> blocksize_bits;
+ if (sector >= last_block) {
+ if (!create)
+ return 0;
+
+ /*
+ * ->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 0;
+ }
cluster = sector >> (sbi->cluster_bits - sb->s_blocksize_bits);
offset = sector & (sbi->sec_per_clus - 1);
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