On 2017年09月19日 16:32, Su Yue wrote:
Lowmem check does not skip invalid type in extent_inline_ref then
calls btrfs_extent_inline_ref_size(type) which causes crash.
Example:
$ ./btrfs-corrupt-block -e -l 20971520 /tmp/data_small
corrupting extent record: key 20971520 169 0
$ btrfs check --mode=lowmem /tmp/data_small
Checking filesystem on /tmp/data_small
UUID: ee205d69-8724-4aa2-a4f5-bc8558a62169
checking extents
ERROR: extent[20971520 16384] backref type mismatch, missing bit: 2
ERROR: extent[20971520 16384] backref generation mismatch,
wanted: 7, have: 0
ERROR: extent[20971520 16384] is referred by other roots than 3
ctree.h:1754: btrfs_extent_inline_ref_size: BUG_ON `1` triggered,
value 1
btrfs(+0x543db)[0x55fabc2ab3db]
btrfs(+0x587f7)[0x55fabc2af7f7]
btrfs(+0x5fa44)[0x55fabc2b6a44]
btrfs(cmd_check+0x194a)[0x55fabc2bd717]
btrfs(main+0x88)[0x55fabc2682e0]
/usr/lib/libc.so.6(__libc_start_main+0xea)[0x7f021c3824ca]
btrfs(_start+0x2a)[0x55fabc267e7a]
[1] 5188 abort (core dumped) btrfs check --mode=lowmem /tmp/data_small
Fix it by checking type before obtaining inline_ref size.
Signed-off-by: Su Yue <suy.f...@cn.fujitsu.com>
Code itself looks good.
And test case please.
Reviewed-by: Qu Wenruo <quwenruo.bt...@gmx.com>
However, such whac-a-mole fix will finally be a nightmare to maintain.
What about integrating all of such validation checkers into one place?
So fsck part will only need to check their cross reference without
bothering such corruption.
Just like the kernel patch I submitted some times ago.
https://www.spinics.net/lists/linux-btrfs/msg68498.html
Thanks,
Qu
---
cmds-check.c | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/cmds-check.c b/cmds-check.c
index 4e0b0fe4..74c10c75 100644
--- a/cmds-check.c
+++ b/cmds-check.c
@@ -11565,6 +11565,10 @@ static int check_tree_block_ref(struct btrfs_root
*root,
offset, level + 1, owner,
NULL);
}
+ } else {
+ error("extent[%llu %u %llu] has unknown ref type: %d",
+ key.objectid, key.type, key.offset, type);
+ break;
}
if (found_ref)
@@ -11831,6 +11835,11 @@ static int check_extent_data_item(struct btrfs_root
*root,
found_dbackref = !check_tree_block_ref(root, NULL,
btrfs_extent_inline_ref_offset(leaf, iref),
0, owner, NULL);
+ } else {
+ error("extent[%llu %u %llu] has unknown ref type: %d",
+ disk_bytenr, BTRFS_EXTENT_DATA_KEY,
+ disk_num_bytes, type);
+ break;
}
if (found_dbackref)
--
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