Re: [PATCH 2/2] btrfs: tree-checker: check item_size for dev_item

[Su Yue <l@damenly.su>]

On Sat 05 Feb 2022 at 22:49, Wang Yugui <wangyugui@e16-tech.com> 
wrote:

> Hi,
>
>> >>>> A btrfs filesystem failed to boot with this patch.
>> >>>>
>> >>>> corrupt leaf: root=3 block=1081344 slot=0 devid=1 invalid 
>> >>>> item
>> >>>> size: has 0 expect 98
>> >>>>
>> >>>> Any way to fix it online?
>> >>>
>> >>> This btrfs filesystem is created by centos 7.9 installer 
>> >>> (btrfs
>> >>> 4.9?)
>> >>> about 1 years ago.  and then mainly writen by kernel
>> >>> 5.4/5.10/5.15.
>> >>>
>> >> Yes, btrfs-progs v4.9 and v3.10 based kernel.
>> >> I created a btrfs and it looks fine.
>> >> Could please provide output of
>> >> btrfs inspect-internal dump-tree $device -t 3
>> >> ?
>> >> You can trim it if the content is too long only leaf 1081344 
>> >> is needed.
>> >
>> > Hi,
>> >
>> > # btrfs filesystem show /
>> > Label: 'OS_T640'  uuid: 73dcce98-8f6b-4ec8-bfac-fa7c7c87409d
>> >          Total devices 10 FS bytes used 5.53TiB
>> >          devid    1 size 799.00GiB used 332.01GiB path 
>> >          /dev/sda2
>> >          devid    2 size 1.75TiB used 741.00GiB path 
>> >          /dev/sdg1
>> >          devid    3 size 1.75TiB used 745.00GiB path 
>> >          /dev/sdj1
>> >          devid    4 size 1.75TiB used 740.00GiB path 
>> >          /dev/sdi1
>> >          devid    5 size 1.75TiB used 745.00GiB path 
>> >          /dev/sdd1
>> >          devid    6 size 1.75TiB used 480.00GiB path 
>> >          /dev/sde1
>> >          devid    7 size 1.75TiB used 480.00GiB path 
>> >          /dev/sdh1
>> >          devid    8 size 1.75TiB used 479.00GiB path 
>> >          /dev/sdc1
>> >          devid    9 size 1.75TiB used 480.00GiB path 
>> >          /dev/sdb1
>> >          devid   10 size 1.75TiB used 479.00GiB path 
>> >          /dev/sdf1
>> >
>> > #btrfs inspect-internal dump-tree /dev/sda2 -t 3 > 3.txt
>> >
>> > and then 3.txt is zipped as  this attachment file(3.zip)
>>
>> Full dmesg of the boot failure please.
>>
>> The dump-tree shows the device item is completely sane, it has 
>> size 98,
>> not the value (0) reported from tree-checker.
>>
>> Thus I don't know why tree-checker is reporting this problem.
>>
>
> This (attachment file boot.dmesg.txt.zip ) is the full dmesg 
> output
>
As Qu suggested to me, would you plase provide output after
apply of the following diff? (It may crash the kernel if there is 
*real*
one invalid dev_item).

diff --git a/fs/btrfs/tree-checker.c b/fs/btrfs/tree-checker.c
index 9fd145f1c4bc..5fb981b4b42a 100644
--- a/fs/btrfs/tree-checker.c
+++ b/fs/btrfs/tree-checker.c
@@ -25,6 +25,7 @@
 #include "volumes.h"
 #include "misc.h"
 #include "btrfs_inode.h"
+#include "print-tree.h"

 /*
  * Error message should follow the following format:
@@ -977,6 +978,7 @@ static int check_dev_item(struct extent_buffer 
*leaf,
        if (unlikely(item_size != sizeof(*ditem))) {
                dev_item_err(leaf, slot, "invalid item size: has 
                %u expect %zu",
                             item_size, sizeof(*ditem));
+               btrfs_print_leaf(leaf);
                return -EUCLEAN;
        }


--
Su
> Best Regards
> Wang Yugui (wangyugui@e16-tech.com)
> 2022/02/05
>
> [2. application/x-zip-compressed; boot.dmesg.txt.zip]...