On 2017年09月19日 17:48, Su Yue wrote:
On 09/19/2017 04:48 PM, Qu Wenruo wrote:
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.
Thanks for review. I'll add test case in next version.
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.
I was confused how to fix the bug(new checker or little changes
in this patch).
The reason why I fix it in this way is that most callers do
check type before calling btrfs_extent_inline_ref_size().
Since you prefer the former, I'm going to do it.
Current version looks good enough as a fix.
Just saying we'd better using an integrated solution later.
Thanks,
Qu
Thanks
Su
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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