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fat: mmu_private race fix

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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>
This commit is contained in:
OGAWA Hirofumi
2008-11-06 12:53:57 -08:00
committed by Linus Torvalds
parent 0e75f5da06
commit 2bdf67eb16
4 changed files with 25 additions and 10 deletions
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4
fs/fat/inode.c
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@@ -64,7 +64,7 @@ static inline int __fat_get_block(struct inode *inode, sector_t iblock,
sector_t phys;
int err, offset;
err = fat_bmap(inode, iblock, &phys, &mapped_blocks);
err = fat_bmap(inode, iblock, &phys, &mapped_blocks, create);
if (err)
return err;
if (phys) {
@@ -94,7 +94,7 @@ static inline int __fat_get_block(struct inode *inode, sector_t iblock,
*max_blocks = min(mapped_blocks, *max_blocks);
MSDOS_I(inode)->mmu_private += *max_blocks << sb->s_blocksize_bits;
err = fat_bmap(inode, iblock, &phys, &mapped_blocks);
err = fat_bmap(inode, iblock, &phys, &mapped_blocks, create);
if (err)
return err;