From: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
To: akpm@linux-foundation.org
Cc: linux-kernel@vger.kernel.org, hirofumi@mail.parknet.co.jp
Subject: [PATCH 20/21] fat: ->i_pos race fix
Date: Wed, 15 Oct 2008 22:58:01 +0900 [thread overview]
Message-ID: <ed5d0b893e848f5f6e92022369.ps@mail.parknet.co.jp> (raw)
In-Reply-To: <01d62c0f3e848f5f6e91922369.ps@mail.parknet.co.jp>
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>
---
fs/fat/inode.c | 21 +++++++++++++++++++--
1 file changed, 19 insertions(+), 2 deletions(-)
diff -puN fs/fat/inode.c~fat_i_pos-race-fix fs/fat/inode.c
--- linux-2.6/fs/fat/inode.c~fat_i_pos-race-fix 2008-09-29 19:04:03.000000000 +0900
+++ linux-2.6-hirofumi/fs/fat/inode.c 2008-09-29 19:04:03.000000000 +0900
@@ -542,6 +542,20 @@ static int fat_statfs(struct dentry *den
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
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);
_
next prev parent reply other threads:[~2008-10-15 14:06 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-10-15 13:57 [PATCH 01/21] fat: document additional vfat mount options OGAWA Hirofumi
2008-10-15 13:57 ` [PATCH 02/21] fat: move fs/vfat/* and fs/msdos/* to fs/fat OGAWA Hirofumi
2008-10-15 13:57 ` [PATCH 03/21] fat: split include/msdos_fs.h OGAWA Hirofumi
2008-10-15 13:57 ` [PATCH 04/21] fat: Fix and cleanup timestamp conversion OGAWA Hirofumi
2008-10-15 13:57 ` [PATCH 05/21] fat: use generic_file_llseek() for directory OGAWA Hirofumi
2008-10-15 13:57 ` [PATCH 06/21] fat: cleanup fat_parse_long() error handling OGAWA Hirofumi
2008-10-15 13:57 ` [PATCH 07/21] fat: improve fat_hash() OGAWA Hirofumi
2008-10-15 13:57 ` [PATCH 08/21] fat: Fix fat_ent_update_ptr() for FAT12 OGAWA Hirofumi
2008-10-15 13:57 ` [PATCH 09/21] fat: use fat_detach() in fat_clear_inode() OGAWA Hirofumi
2008-10-15 13:57 ` [PATCH 10/21] vfat: Fix vfat_find() error path in vfat_lookup() OGAWA Hirofumi
2008-10-15 13:57 ` [PATCH 11/21] fat: Fix/Cleanup dcache handling for vfat OGAWA Hirofumi
2008-10-15 13:57 ` [PATCH 12/21] fat: Kill d_invalidate() in vfat_lookup() OGAWA Hirofumi
2008-10-15 13:57 ` [PATCH 13/21] fat: Cleanup msdos_lookup() OGAWA Hirofumi
2008-10-15 13:58 ` [PATCH 14/21] fat: Cleanup FAT attribute stuff OGAWA Hirofumi
2008-10-15 13:58 ` [PATCH 15/21] fat: Fix ATTR_RO in the case of (~umask & S_WUGO) == 0 OGAWA Hirofumi
2008-10-15 13:58 ` [PATCH 16/21] fat: Fix ATTR_RO for directory OGAWA Hirofumi
2008-10-15 13:58 ` [PATCH 17/21] fat: Fix _fat_bmap() race OGAWA Hirofumi
2008-10-15 13:58 ` [PATCH 18/21] fat: Add printf attribute to fat_fs_panic() OGAWA Hirofumi
2008-10-15 13:58 ` [PATCH 19/21] fat: mmu_private race fix OGAWA Hirofumi
2008-10-15 13:58 ` OGAWA Hirofumi [this message]
2008-10-15 13:58 ` [PATCH 21/21] fat: i_blocks warning fix OGAWA Hirofumi
2009-03-17 23:33 ` [PATCH 02/21] fat: move fs/vfat/* and fs/msdos/* to fs/fat Pozsar Balazs
2008-10-15 22:07 ` [PATCH 01/21] fat: document additional vfat mount options Andrew Morton
2008-10-15 23:04 ` OGAWA Hirofumi
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