diff options
| author | Jan Kara <jack@suse.cz> | 2009-04-27 16:43:48 +0200 |
|---|---|---|
| committer | Al Viro <viro@zeniv.linux.org.uk> | 2009-06-11 21:36:03 -0400 |
| commit | 5a3e5cb8e08bd876e2542c1451c9a93dab1b0e39 (patch) | |
| tree | 3b792d21246f1001adeca8b67df24ca71593dd3f /fs/internal.h | |
| parent | 876a9f76abbcb775f8d21cbc99fa161f9e5937f1 (diff) | |
| download | linux-5a3e5cb8e08bd876e2542c1451c9a93dab1b0e39.tar.bz2 | |
vfs: Fix sys_sync() and fsync_super() reliability (version 4)
So far, do_sync() called:
sync_inodes(0);
sync_supers();
sync_filesystems(0);
sync_filesystems(1);
sync_inodes(1);
This ordering makes it kind of hard for filesystems as sync_inodes(0) need not
submit all the IO (for example it skips inodes with I_SYNC set) so e.g. forcing
transaction to disk in ->sync_fs() is not really enough. Therefore sys_sync has
not been completely reliable on some filesystems (ext3, ext4, reiserfs, ocfs2
and others are hit by this) when racing e.g. with background writeback. A
similar problem hits also other filesystems (e.g. ext2) because of
write_supers() being called before the sync_inodes(1).
Change the ordering of calls in do_sync() - this requires a new function
sync_blockdevs() to preserve the property that block devices are always synced
after write_super() / sync_fs() call.
The same issue is fixed in __fsync_super() function used on umount /
remount read-only.
[AV: build fixes]
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'fs/internal.h')
| -rw-r--r-- | fs/internal.h | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/fs/internal.h b/fs/internal.h index 6d4ef208ef65..343a537ab809 100644 --- a/fs/internal.h +++ b/fs/internal.h @@ -71,3 +71,12 @@ extern void chroot_fs_refs(struct path *, struct path *); * file_table.c */ extern void mark_files_ro(struct super_block *); + +/* + * super.c + */ +#ifdef CONFIG_BLOCK +extern void sync_blockdevs(void); +#else +static inline void sync_blockdevs(void) { } +#endif |