Re: How to fix/remove "csum failed ino" error

[Anatol Pomozov <anatol.pomozov@gmail.com>]

Hi, Frank

Thanks for your answer.

On Thu, Nov 7, 2013 at 8:41 AM, Frank Holton <fholton@gmail.com> wrote:
> Hey Anatol,
>
> I just checked and on my filesystem inode number 362 corresponds to
> part of the free space cache. You can check this yourself by running
> (as root)
>
> btrfs-debug-tree /dev/sdb | grep "(362 " -A 3 -B 1
>
> where /dev/sdb is one of the devices from your filesystem.
>
> It printed the following for me, note the location key (362
> INODE_ITEM) under the FREE_SPACE key. Yours might be different but if
> you see FREE_SPACE that points to the free space cache.
>
> item 100 key (362 INODE_ITEM 0) itemoff 21857 itemsize 160
>                 inode generation 2004 transid 2004 size 262144 block
> group 0 mode 100600 links 1
>         item 101 key (362 EXTENT_DATA 0) itemoff 21804 itemsize 53
>                 extent data disk byte 41903296512 nr 262144
>                 extent data offset 0 nr 262144 ram 262144
>                 extent compression 0
> --
>         item 148 key (FREE_SPACE UNTYPED 113845993472) itemoff 23807 itemsize 41
>                 location key (362 INODE_ITEM 0)
>                 cache generation 2004 entries 2 bitmaps 0


Indeed my case similar to yours

# btrfs-debug-tree /dev/sda3 | grep "(309 " -A 3 -B 1

item 1 key (309 INODE_ITEM 0) itemoff 3675 itemsize 160
    inode generation 190480 transid 190647 size 0 block group 0 mode
100600 links 1
item 51 key (FREE_SPACE UNTYPED 56937676800) itemoff 1863 itemsize 41
    location key (309 INODE_ITEM 0)

So I mounted my filesystem with 'clear_cache' flag:

# mount -o clear_cache /dev/sda3 mydata/

mount says:
/dev/sdc1 on /root/mydata type btrfs (rw,relatime,space_cache,clear_cache)

dmesg also mentions the cache:

[  634.991845] device fsid 25e6a6fa-fe1f-4be5-a638-eeac948f8c21 devid
9 transid 190479 /dev/sda3
[  634.993431] btrfs: force clearing of disk cache
[  634.993435] btrfs: disk space caching is enabled
[  635.046803] btrfs: bdev /dev/sda3 errs: wr 0, rd 0, flush 0,
corrupt 58481, gen 0


The I started raid1 rebalance but the error still presents:

[ 1571.787664] BTRFS info (device sda3): csum failed ino 309 off
4993024 csum 1283121890 private 3720296651
[ 1571.791027] BTRFS info (device sda3): csum failed ino 309 off
5242880 csum 857237386 private 2562492866
[ 1571.793998] BTRFS info (device sda3): csum failed ino 309 off
5767168 csum 645194099 private 3149624654
[ 1571.794389] BTRFS info (device sda3): csum failed ino 309 off
4993024 csum 1283121890 private 3720296651


So my problem still exists. How to fix the block with wrong csum?