From e073b6e14f6a0dcffa7a6204a7593a4b7ea9edb3 Mon Sep 17 00:00:00 2001 From: Qu Wenruo Date: Wed, 18 Dec 2019 09:19:42 +0800 Subject: [PATCH] btrfs-progs: fix superblock range exclusion check [BUG] For certain btrfs images, a BUG_ON() can be triggered at open_ctree() time: Opening filesystem to check... extent_io.c:158: insert_state: BUG_ON `end < start` triggered, value 1 btrfs(+0x2de57)[0x560c4d7cfe57] btrfs(+0x2e210)[0x560c4d7d0210] btrfs(set_extent_bits+0x254)[0x560c4d7d0854] btrfs(exclude_super_stripes+0xbf)[0x560c4d7c65ff] btrfs(btrfs_read_block_groups+0x29d)[0x560c4d7c698d] btrfs(btrfs_setup_all_roots+0x3f3)[0x560c4d7c0b23] btrfs(+0x1ef53)[0x560c4d7c0f53] btrfs(open_ctree_fs_info+0x90)[0x560c4d7c11a0] btrfs(+0x6d3f9)[0x560c4d80f3f9] btrfs(main+0x94)[0x560c4d7b60c4] /usr/lib/libc.so.6(__libc_start_main+0xf3)[0x7fd189773ee3] btrfs(_start+0x2e)[0x560c4d7b635e] [CAUSE] This is caused by passing @len == 0 to add_excluded_extent(), which means one reverse mapped range is just out of the block group range, normally means a by-one error. [FIX] Fix the boundary check on the reserve mapped range against block group range. If a reverse mapped super block starts at the end of the block group, it doesn't cover so we don't need to bother the case. Issue: #210 Signed-off-by: Qu Wenruo Signed-off-by: David Sterba --- extent-tree.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/extent-tree.c b/extent-tree.c index 6288c8a3..7ba80375 100644 --- a/extent-tree.c +++ b/extent-tree.c @@ -3640,7 +3640,7 @@ int exclude_super_stripes(struct btrfs_fs_info *fs_info, while (nr--) { u64 start, len; - if (logical[nr] > cache->key.objectid + + if (logical[nr] >= cache->key.objectid + cache->key.offset) continue;