From cfd80bb2aa4da829288dfbaff1cfbd39fa10e8d2 Mon Sep 17 00:00:00 2001 From: Josef Bacik Date: Fri, 14 Feb 2020 15:22:06 -0500 Subject: [PATCH] btrfs: set update the uuid generation as soon as possible BugLink: https://bugs.launchpad.net/bugs/1874502 commit 75ec1db8717a8f0a9d9c8d033e542fdaa7b73898 upstream. In my EIO stress testing I noticed I was getting forced to rescan the uuid tree pretty often, which was weird. This is because my error injection stuff would sometimes inject an error after log replay but before we loaded the UUID tree. If log replay committed the transaction it wouldn't have updated the uuid tree generation, but the tree was valid and didn't change, so there's no reason to not update the generation here. Fix this by setting the BTRFS_FS_UPDATE_UUID_TREE_GEN bit immediately after reading all the fs roots if the uuid tree generation matches the fs generation. Then any transaction commits that happen during mount won't screw up our uuid tree state, forcing us to do needless uuid rescans. Fixes: 70f801754728 ("Btrfs: check UUID tree during mount if required") CC: stable@vger.kernel.org # 4.19+ Signed-off-by: Josef Bacik Reviewed-by: David Sterba Signed-off-by: David Sterba Signed-off-by: Greg Kroah-Hartman Signed-off-by: Kamal Mostafa Signed-off-by: Kelsey Skunberg --- fs/btrfs/disk-io.c | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-) diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c index 830240a21d9a..654618d7ca0a 100644 --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -2795,6 +2795,18 @@ retry_root_backup: fs_info->generation = generation; fs_info->last_trans_committed = generation; + /* + * If we have a uuid root and we're not being told to rescan we need to + * check the generation here so we can set the + * BTRFS_FS_UPDATE_UUID_TREE_GEN bit. Otherwise we could commit the + * transaction during a balance or the log replay without updating the + * uuid generation, and then if we crash we would rescan the uuid tree, + * even though it was perfectly fine. + */ + if (fs_info->uuid_root && !btrfs_test_opt(fs_info, RESCAN_UUID_TREE) && + fs_info->generation == btrfs_super_uuid_tree_generation(disk_super)) + set_bit(BTRFS_FS_UPDATE_UUID_TREE_GEN, &fs_info->flags); + ret = btrfs_recover_balance(fs_info); if (ret) { btrfs_err(fs_info, "failed to recover balance: %d", ret); @@ -3017,8 +3029,6 @@ retry_root_backup: close_ctree(fs_info); return ret; } - } else { - set_bit(BTRFS_FS_UPDATE_UUID_TREE_GEN, &fs_info->flags); } set_bit(BTRFS_FS_OPEN, &fs_info->flags); -- 2.39.5