Re: [PATCH] btrfs-progs: Enhance read_tree_block to avoid memory corruption.

[Qu Wenruo <quwenruo@cn.fujitsu.com>]

-------- Original Message  --------
Subject: Re: [PATCH] btrfs-progs: Enhance read_tree_block to avoid 
memory corruption.
From: David Sterba <dsterba@suse.cz>
To: David Sterba <dsterba@suse.cz>
Date: 2015年05月21日 23:04

> On Thu, May 21, 2015 at 04:52:49PM +0200, David Sterba wrote:
>> The test 001-bad-file-extent-bytenr fails with this patch (and passes
>> otherwise). Can you please have a look?
>
> First check expectedly finds problems and fails, then repair is supposed
> to fix it, but the final check still finds problems because of the
> enhancements you've added:
>
> # output from the final check:
> checking extents
> invalid nr_items: 0
> Errors found in extent allocation tree or chunk allocation
> checking free space cache
> checking fs roots
> root 5 inode 257 errors 1000, some csum missing
> Checking filesystem on .../001-bad-file-extent-bytenr/default_case.img.restored
> UUID: 17442351-31aa-45fa-9503-90fd48874c3e
> cache and super generation don't match, space cache will be invalidated
> found 1081346 bytes used err is 1
> total csum bytes: 1024
> total tree bytes: 24576
> total fs tree bytes: 4096
> total extent tree bytes: 4096
> btree space waste bytes: 16507
> file data blocks allocated: 1310720
>   referenced 1310720
> btrfs-progs v4.0.1-2-gb7cf7c5c181d
> failed: .../btrfs check .../001-bad-file-extent-bytenr/default_case.img.restored
>
> It's "invalid nr_items: 0", while in the unpatched test there's
>
> Device extent[1, 29360128, 8388608] didn't find the relative chunk.
> Device extent[1, 1111490560, 1073741824] didn't find the relative chunk.
> Dev extent's total-byte(2185232384) is not equal to byte-used(1103101952) in dev[1, 216, 1]
>
Oh... I forgot the fact that empty tree is allowed to exist...
I'll update the patch soon.

Thanks
Qu