Fwd: [PATCH] Btrfs: fix a warning when iput a file

[Shilong Wang <wangshilong1991@gmail.com>]

CC:linux-btrfs

---------- Forwarded message ----------
From: Shilong Wang <wangshilong1991@gmail.com>
Date: 2013/12/14
Subject: Re: [PATCH] Btrfs: fix a warning when iput a file
To: bo.li.liu@oracle.com


Hello Liu

2013/12/14 Liu Bo <bo.li.liu@oracle.com>:
> On Sat, Dec 14, 2013 at 03:27:31PM +0800, Wang Shilong wrote:
>> See the warning below:
>>
>> [ 1209.102076]  [<ffffffffa04721b9>] remove_extent_mapping+0x69/0x70 [btrfs]
>> [ 1209.102084]  [<ffffffffa0466b06>] btrfs_evict_inode+0x96/0x4d0 [btrfs]
>> [ 1209.102089]  [<ffffffff81073010>] ? wake_atomic_t_function+0x40/0x40
>> [ 1209.102092]  [<ffffffff8118ab2e>] evict+0x9e/0x190
>> [ 1209.102094]  [<ffffffff8118b313>] iput+0xf3/0x180
>> [ 1209.102101]  [<ffffffffa0461fd1>] btrfs_run_delayed_iputs+0xb1/0xd0 [btrfs]
>> [ 1209.102107]  [<ffffffffa045d358>] __btrfs_end_transaction+0x268/0x350 [btrfs]
>>
>> clear extent bit here to avoid triggering WARN_ON() in remove_extent_mapping()
>
> Why PINNED and LOGGING isn't unset as usual?
>

Flippe sent an improved patch regarding evict inode:
https://patchwork.kernel.org/patch/3204281/

In btrfs_invalidatepages(), if we are evicting an inode, we will skip
usual operation that is operated page by page.

Rather than we do it more effectively, that we operate extent_map and
extent_state structure, this will be faster!

So for now code , after calling truncate_inode_pages(), PINNED and
LOGGED won't be unset
as usual(Maybe a better solution is to move remove_extent_mappin after
we clear extent state).

Correct me if i am wrong here.

Thanks,
Wang

> -liubo
>
>>
>> Signed-off-by: Wang Shilong <wangsl.fnst@cn.fujitsu.com>
>> ---
>>  fs/btrfs/inode.c | 2 ++
>>  1 file changed, 2 insertions(+)
>>
>> diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
>> index e889779..c0f0f9d 100644
>> --- a/fs/btrfs/inode.c
>> +++ b/fs/btrfs/inode.c
>> @@ -4515,6 +4515,8 @@ static void evict_inode_truncate_pages(struct inode *inode)
>>
>>               node = rb_first(&map_tree->map);
>>               em = rb_entry(node, struct extent_map, rb_node);
>> +             clear_bit(EXTENT_FLAG_PINNED, &em->flags);
>> +             clear_bit(EXTENT_FLAG_LOGGING, &em->flags);
>>               remove_extent_mapping(map_tree, em);
>>               free_extent_map(em);
>>       }
>> --
>> 1.8.3.1
>>
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