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authorJan Kara <jack@suse.cz>2009-04-27 16:43:48 +0200
committerAl Viro <viro@zeniv.linux.org.uk>2009-06-11 21:36:03 -0400
commit5a3e5cb8e08bd876e2542c1451c9a93dab1b0e39 (patch)
tree3b792d21246f1001adeca8b67df24ca71593dd3f /fs/internal.h
parent876a9f76abbcb775f8d21cbc99fa161f9e5937f1 (diff)
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.h9
1 files changed, 9 insertions, 0 deletions
diff --git a/fs/internal.h b/fs/internal.h
index 6d4ef208ef6..343a537ab80 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