summaryrefslogtreecommitdiff
path: root/fs/sync.c
diff options
context:
space:
mode:
authorJan Kara <jack@suse.cz>2009-04-27 18:43:48 +0400
committerAl Viro <viro@zeniv.linux.org.uk>2009-06-12 05:36:03 +0400
commit5a3e5cb8e08bd876e2542c1451c9a93dab1b0e39 (patch)
tree3b792d21246f1001adeca8b67df24ca71593dd3f /fs/sync.c
parent876a9f76abbcb775f8d21cbc99fa161f9e5937f1 (diff)
downloadlinux-5a3e5cb8e08bd876e2542c1451c9a93dab1b0e39.tar.xz
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/sync.c')
-rw-r--r--fs/sync.c4
1 files changed, 3 insertions, 1 deletions
diff --git a/fs/sync.c b/fs/sync.c
index 7abc65fbf21d..631fd5aece78 100644
--- a/fs/sync.c
+++ b/fs/sync.c
@@ -13,6 +13,7 @@
#include <linux/pagemap.h>
#include <linux/quotaops.h>
#include <linux/buffer_head.h>
+#include "internal.h"
#define VALID_FLAGS (SYNC_FILE_RANGE_WAIT_BEFORE|SYNC_FILE_RANGE_WRITE| \
SYNC_FILE_RANGE_WAIT_AFTER)
@@ -26,10 +27,11 @@ static void do_sync(unsigned long wait)
wakeup_pdflush(0);
sync_inodes(0); /* All mappings, inodes and their blockdevs */
vfs_dq_sync(NULL);
+ sync_inodes(wait); /* Mappings, inodes and blockdevs, again. */
sync_supers(); /* Write the superblocks */
sync_filesystems(0); /* Start syncing the filesystems */
sync_filesystems(wait); /* Waitingly sync the filesystems */
- sync_inodes(wait); /* Mappings, inodes and blockdevs, again. */
+ sync_blockdevs();
if (!wait)
printk("Emergency Sync complete\n");
if (unlikely(laptop_mode))