From 4ded4f639533ed5f02a0f0ab20d43bb9659c91f8 Mon Sep 17 00:00:00 2001 From: Stefan Behrens Date: Wed, 14 Nov 2012 18:57:29 +0000 Subject: [PATCH] Btrfs: fix BUG() in scrub when first superblock reading gives EIO This fixes a very special case that can be reproduced by just disconnecting a disk at runtime, and without unmounting the filesystem first, start scrub on the filesystem with the disconnected disk. All read and write EIOs are handled correctly, only the first superblock is an exception and gives a BUG() in a subfunction. The BUG() is correct, it would crash later otherwise. The subfunction must not be called for superblocks and this is what the fix changes. Reported-by: Joeri Vanthienen Signed-off-by: Stefan Behrens Signed-off-by: Chris Mason --- fs/btrfs/scrub.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c index 8db6a6413a5f..bdbb94f245c9 100644 --- a/fs/btrfs/scrub.c +++ b/fs/btrfs/scrub.c @@ -785,6 +785,17 @@ static int scrub_handle_errored_block(struct scrub_block *sblock_to_check) BUG_ON(sblock_to_check->page_count < 1); fs_info = sctx->dev_root->fs_info; + if (sblock_to_check->pagev[0]->flags & BTRFS_EXTENT_FLAG_SUPER) { + /* + * if we find an error in a super block, we just report it. + * They will get written with the next transaction commit + * anyway + */ + spin_lock(&sctx->stat_lock); + ++sctx->stat.super_errors; + spin_unlock(&sctx->stat_lock); + return 0; + } length = sblock_to_check->page_count * PAGE_SIZE; logical = sblock_to_check->pagev[0]->logical; generation = sblock_to_check->pagev[0]->generation;