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| author | OGAWA Hirofumi <hirofumi@mail.parknet.co.jp> | 2008-11-06 12:53:57 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2008-11-06 15:41:21 -0800 |
| commit | 9ca59f4c3d28df14a1545a1e2832f34a0a50e3ed (patch) | |
| tree | 4a9d307e2a3541765cf194f27d873c6d06e5d960 /fs/fat | |
| parent | 2bdf67eb1631f30e2f3f5d49e4007c76e88877a8 (diff) | |
| download | lwn-9ca59f4c3d28df14a1545a1e2832f34a0a50e3ed.tar.gz lwn-9ca59f4c3d28df14a1545a1e2832f34a0a50e3ed.zip | |
fat: ->i_pos race fix
i_pos is 64bits value, hence it's not atomic to update.
Important place is fat_write_inode() only, other places without lock
are just for printk().
This adds lock for "BITS_PER_LONG == 32" kernel.
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>
Diffstat (limited to 'fs/fat')
| -rw-r--r-- | fs/fat/inode.c | 21 |
1 files changed, 19 insertions, 2 deletions
diff --git a/fs/fat/inode.c b/fs/fat/inode.c index 9e37ad93c730..bdd8fb7be2ca 100644 --- a/fs/fat/inode.c +++ b/fs/fat/inode.c @@ -542,6 +542,20 @@ static int fat_statfs(struct dentry *dentry, struct kstatfs *buf) return 0; } +static inline loff_t fat_i_pos_read(struct msdos_sb_info *sbi, + struct inode *inode) +{ + loff_t i_pos; +#if BITS_PER_LONG == 32 + spin_lock(&sbi->inode_hash_lock); +#endif + i_pos = MSDOS_I(inode)->i_pos; +#if BITS_PER_LONG == 32 + spin_unlock(&sbi->inode_hash_lock); +#endif + return i_pos; +} + static int fat_write_inode(struct inode *inode, int wait) { struct super_block *sb = inode->i_sb; @@ -551,9 +565,12 @@ static int fat_write_inode(struct inode *inode, int wait) loff_t i_pos; int err; + if (inode->i_ino == MSDOS_ROOT_INO) + return 0; + retry: - i_pos = MSDOS_I(inode)->i_pos; - if (inode->i_ino == MSDOS_ROOT_INO || !i_pos) + i_pos = fat_i_pos_read(sbi, inode); + if (!i_pos) return 0; bh = sb_bread(sb, i_pos >> sbi->dir_per_block_bits); |