vfs: Make sys_sync() use fsync_super() (version 4)
It is unnecessarily fragile to have two places (fsync_super() and do_sync())
doing data integrity sync of the filesystem. Alter __fsync_super() to
accommodate needs of both callers and use it. So after this patch
__fsync_super() is the only place where we gather all the calls needed to
properly send all data on a filesystem to disk.
Nice bonus is that we get a complete livelock avoidance and write_supers()
is now only used for periodic writeback of superblocks.
sync_blockdevs() introduced a couple of patches ago is gone now.
[build fixes folded]
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/sync.c b/fs/sync.c
index 631fd5a..be0798c 100644
--- a/fs/sync.c
+++ b/fs/sync.c
@@ -18,35 +18,24 @@
#define VALID_FLAGS (SYNC_FILE_RANGE_WAIT_BEFORE|SYNC_FILE_RANGE_WRITE| \
SYNC_FILE_RANGE_WAIT_AFTER)
-/*
- * sync everything. Start out by waking pdflush, because that writes back
- * all queues in parallel.
- */
-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_blockdevs();
- if (!wait)
- printk("Emergency Sync complete\n");
- if (unlikely(laptop_mode))
- laptop_sync_completion();
-}
-
SYSCALL_DEFINE0(sync)
{
- do_sync(1);
+ sync_filesystems(0);
+ sync_filesystems(1);
+ if (unlikely(laptop_mode))
+ laptop_sync_completion();
return 0;
}
static void do_sync_work(struct work_struct *work)
{
- do_sync(0);
+ /*
+ * Sync twice to reduce the possibility we skipped some inodes / pages
+ * because they were temporarily locked
+ */
+ sync_filesystems(0);
+ sync_filesystems(0);
+ printk("Emergency Sync complete\n");
kfree(work);
}