Btrfs: deal with bad mappings in btrfs_map_block (9bb91873) · Commits · 戴 / test

Martin Steigerwald reported a BUG_ON() in btrfs_map_block where we didn't find a chunk for a particular block we were trying to map. This happened because the block was bogus. We shouldn't be BUG_ON()'ing in this case, just print a message and return an error. This came from reada_add_block and it appears to deal with an error fine so we should be good there. Thanks, Reported-by:

Martin Steigerwald <Martin@lichtvoll.de> Signed-off-by:

Josef Bacik <jbacik@fusionio.com>

fs/btrfs/volumes.c

+8 −2

Original line number	Diff line number	Diff line
		@@ -4406,10 +4406,16 @@ static int __btrfs_map_block(struct btrfs_fs_info *fs_info, int rw,
		btrfs_crit(fs_info, "unable to find logical %llu len %llu",
		(unsigned long long)logical,
		(unsigned long long)*length);
		BUG();
		return -EINVAL;
		}

		if (em->start > logical \|\| em->start + em->len < logical) {
		btrfs_crit(fs_info, "found a bad mapping, wanted %Lu, "
		"found %Lu-%Lu\n", logical, em->start,
		em->start + em->len);
		return -EINVAL;
		}

		BUG_ON(em->start > logical \|\| em->start + em->len < logical);
		map = (struct map_lookup *)em->bdev;
		offset = logical - em->start;

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