dm cache metadata: fix cmd_read_lock() acquiring write lock

asamy · snitm · commit 6545b60baaf8 · 2016-04-17T11:24:46.000-04:00
Commit 9567366 ("dm cache metadata: fix READ_LOCK macros and cleanup WRITE_LOCK macros") uses down_write() instead of down_read() in cmd_read_lock(), yet up_read() is used to release the lock in READ_UNLOCK(). Fix it. Fixes: 9567366 ("dm cache metadata: fix READ_LOCK macros and cleanup WRITE_LOCK macros") Cc: stable@vger.kernel.org Signed-off-by: Ahmed Samy <f.fallen45@gmail.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
diff --git a/drivers/md/dm-cache-metadata.c b/drivers/md/dm-cache-metadata.c
@@ -894,9 +894,9 @@ static bool cmd_write_lock(struct dm_cache_metadata *cmd)
 
 static bool cmd_read_lock(struct dm_cache_metadata *cmd)
 {
-	down_write(&cmd->root_lock);
+	down_read(&cmd->root_lock);
 	if (cmd->fail_io) {
-		up_write(&cmd->root_lock);
+		up_read(&cmd->root_lock);
 		return false;
 	}
 	return true;

Original file line number	Diff line number	Diff line change
`@@ -894,9 +894,9 @@ static bool cmd_write_lock(struct dm_cache_metadata *cmd)`
`894`	`894`
`895`	`895`	`static bool cmd_read_lock(struct dm_cache_metadata *cmd)`
`896`	`896`	`{`
`897`		`- down_write(&cmd->root_lock);`
	`897`	`+ down_read(&cmd->root_lock);`
`898`	`898`	`if (cmd->fail_io) {`
`899`		`- up_write(&cmd->root_lock);`
	`899`	`+ up_read(&cmd->root_lock);`
`900`	`900`	`return false;`
`901`	`901`	`}`
`902`	`902`	`return true;`