From 835d974fabfa9bff4d173ad03c054ac2f673263f Mon Sep 17 00:00:00 2001 From: Josef Bacik Date: Tue, 19 Mar 2013 12:13:25 -0400 Subject: Btrfs: handle a bogus chunk tree nicely If you restore a btrfs-image file system and try to mount that file system we'll panic. That's because btrfs-image restores and just makes one big chunk to envelope the whole disk, since they are really only meant to be messed with by our btrfs-progs. So fix up btrfs_rmap_block and the callers of it for mount so that we no longer panic but instead just return an error and fail to mount. Thanks, Signed-off-by: Josef Bacik Signed-off-by: Chris Mason --- fs/btrfs/volumes.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) (limited to 'fs/btrfs/volumes.c') diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index 5989a92236f..2854c824ab6 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -4935,7 +4935,18 @@ int btrfs_rmap_block(struct btrfs_mapping_tree *map_tree, em = lookup_extent_mapping(em_tree, chunk_start, 1); read_unlock(&em_tree->lock); - BUG_ON(!em || em->start != chunk_start); + if (!em) { + printk(KERN_ERR "btrfs: couldn't find em for chunk %Lu\n", + chunk_start); + return -EIO; + } + + if (em->start != chunk_start) { + printk(KERN_ERR "btrfs: bad chunk start, em=%Lu, wanted=%Lu\n", + em->start, chunk_start); + free_extent_map(em); + return -EIO; + } map = (struct map_lookup *)em->bdev; length = em->len; -- cgit v1.2.3-18-g5258