dm: split dm_suspend io_lock hold into two

Change io_locking to allow processing flush in separate thread. Because we have DMF_BLOCK_IO already set, any possible new ios are queued in dm_requests now. In the case of interrupting previous wait there can be more ios queued (we unlocked io_lock for a while) but this is safe. Signed-off-by: Milan Broz <[email protected]> Signed-off-by: Alasdair G Kergon <[email protected]>
mrcsosa · Feb 8, 2008 · 94d6351 · 94d6351
1 parent 73d410c
commit 94d6351
Showing 1 changed file with 2 additions and 1 deletion.
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
@@ -1434,17 +1434,18 @@ int dm_suspend(struct mapped_device *md, unsigned suspend_flags)
 
 	if (noflush)
 		__merge_pushback_list(md);
+	up_write(&md->io_lock);
 
 	/* were we interrupted ? */
 	if (pending) {
+		down_write(&md->io_lock);
 		__flush_deferred_io(md);
 		up_write(&md->io_lock);
 
 		unlock_fs(md);
 		r = -EINTR;
 		goto out; /* pushback list is already flushed, so skip flush */
 	}
-	up_write(&md->io_lock);
 
 	dm_table_postsuspend_targets(map);