From b1f11aff04cc86daa0757ada5deb669a92a8f0fb Mon Sep 17 00:00:00 2001 From: Joe Thornber Date: Thu, 11 Jun 2015 17:11:48 +0100 Subject: [PATCH] dm thin metadata: fix a race when entering fail mode In dm_thin_find_block() the ->fail_io flag was checked outside the metadata device's root_lock, causing dm_thin_find_block() to race with the setting of this flag. Signed-off-by: Joe Thornber Signed-off-by: Mike Snitzer --- drivers/md/dm-thin-metadata.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/drivers/md/dm-thin-metadata.c b/drivers/md/dm-thin-metadata.c index 8b521e3e1e1b..48dfe3c4d6aa 100644 --- a/drivers/md/dm-thin-metadata.c +++ b/drivers/md/dm-thin-metadata.c @@ -1390,10 +1390,11 @@ int dm_thin_find_block(struct dm_thin_device *td, dm_block_t block, dm_block_t keys[2] = { td->id, block }; struct dm_btree_info *info; - if (pmd->fail_io) - return -EINVAL; - down_read(&pmd->root_lock); + if (pmd->fail_io) { + up_read(&pmd->root_lock); + return -EINVAL; + } if (can_issue_io) { info = &pmd->info; -- 2.20.1