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From: Tsutomu Itoh <t-itoh@jp.fujitsu.com>
To: Li Zefan <lizf@cn.fujitsu.com>
Cc: Linux Btrfs <linux-btrfs@vger.kernel.org>
Subject: Re: The value displayed by 'ls -s' command is strange.
Date: Wed, 08 Dec 2010 08:53:55 +0900	[thread overview]
Message-ID: <4CFEC913.4020703@jp.fujitsu.com> (raw)
In-Reply-To: <4CFDFD92.9090208@cn.fujitsu.com>


(2010/12/07 18:25), Li Zefan wrote:
> Tsutomu Itoh wrote:
>> Hi,
>>
>> I think that the disk allocation size of each file becomes a monotone increase
>> when the file is made.
>> But, it sometimes return to 0.  Is it correct?
>>
> 
> The # of blocks is:
> 
>         stat->blocks = (inode_get_bytes(inode) +
>                         BTRFS_I(inode)->delalloc_bytes) >> 9;
> 
> So I think after sub(delalloc_bytes) and before inode_add_bytes(), you may
> see 0 value.

Yes, I also think so.
But, I think that such a state is too long for only the update timing...

> 
>>
>> The result of the test at 2.6.37-rc4 is shown below. 
>> (see inode no. 291)
>>
>>     # df -T /test14
>>     Filesystem    Type   1K-blocks      Used Available Use% Mounted on
>>     /dev/sdd14   btrfs     4162560      8736   3709440   1% /test14
>>     # dd if=/dev/zero of=/test14/dir/as001.26603 bs=1M count=100
>>     # dd if=/dev/zero of=/test14/dir/as002.26603 bs=1M count=200
>>     # dd if=/dev/zero of=/test14/dir/sy001.26603 bs=1M count=300 oflag=direct
>>     # dd if=/dev/zero of=/test14/dir/as003.26603 bs=1M count=400
>>     # ls -lis /test14/dir
>>     total 406528
>>     288      0 -rw-r--r-- 1 root root 104857600 Dec  7 15:07 as001.26603
>>     289      0 -rw-r--r-- 1 root root 209715200 Dec  7 15:07 as002.26603
>>  -> 291  99328 -rw-r--r-- 1 root root 419430400 Dec  7 15:08 as003.26603
>>     290 307200 -rw-r--r-- 1 root root 314572800 Dec  7 15:08 sy001.26603
>>     # sleep 3
>>     # ls -lis /test14/dir
>>     total 406528
>>     288      0 -rw-r--r-- 1 root root 104857600 Dec  7 15:07 as001.26603
>>     289      0 -rw-r--r-- 1 root root 209715200 Dec  7 15:07 as002.26603
>>  -> 291  99328 -rw-r--r-- 1 root root 419430400 Dec  7 15:08 as003.26603
>>     290 307200 -rw-r--r-- 1 root root 314572800 Dec  7 15:08 sy001.26603
>>     # sleep 3
>>     # ls -lis /test14/dir
>>     total 307200
>>     288      0 -rw-r--r-- 1 root root 104857600 Dec  7 15:07 as001.26603
>>     289      0 -rw-r--r-- 1 root root 209715200 Dec  7 15:07 as002.26603
>>  -> 291      0 -rw-r--r-- 1 root root 419430400 Dec  7 15:08 as003.26603
>>     290 307200 -rw-r--r-- 1 root root 314572800 Dec  7 15:08 sy001.26603
>>     # sleep 3
>>     # ls -lis /test14/dir
>>     total 409600
>>     288 102400 -rw-r--r-- 1 root root 104857600 Dec  7 15:07 as001.26603
>>     289      0 -rw-r--r-- 1 root root 209715200 Dec  7 15:07 as002.26603
>>  -> 291      0 -rw-r--r-- 1 root root 419430400 Dec  7 15:08 as003.26603
>>     290 307200 -rw-r--r-- 1 root root 314572800 Dec  7 15:08 sy001.26603
>>     # sync
>>     # ls -lis /test14/dir
>>     total 1024000
>>     288 102400 -rw-r--r-- 1 root root 104857600 Dec  7 15:07 as001.26603
>>     289 204800 -rw-r--r-- 1 root root 209715200 Dec  7 15:07 as002.26603
>>  -> 291 409600 -rw-r--r-- 1 root root 419430400 Dec  7 15:08 as003.26603
>>     290 307200 -rw-r--r-- 1 root root 314572800 Dec  7 15:08 sy001.26603
>>
>> The trace result of btrfs_getattr() is shown below. 
>>
>>  Dec  7 15:08:03 luna kernel: ino:291 blocks:198656 i_blocks:0 i_bytes:0 delalloc_bytes:101711872
>>  Dec  7 15:08:06 luna kernel: ino:291 blocks:198656 i_blocks:0 i_bytes:0 delalloc_bytes:101711872
>>  Dec  7 15:08:09 luna kernel: ino:291 blocks:0 i_blocks:0 i_bytes:0 delalloc_bytes:0
>>  Dec  7 15:08:12 luna kernel: ino:291 blocks:0 i_blocks:0 i_bytes:0 delalloc_bytes:0
>>  Dec  7 15:08:18 luna kernel: ino:291 blocks:819200 i_blocks:819200 i_bytes:0 delalloc_bytes:0
>>
>>
>> Regards,
>> Itoh
>>
> --
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> 


  reply	other threads:[~2010-12-07 23:53 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-12-07  7:59 The value displayed by 'ls -s' command is strange Tsutomu Itoh
2010-12-07  9:25 ` Li Zefan
2010-12-07 23:53   ` Tsutomu Itoh [this message]
2010-12-09 10:42     ` Miao Xie
2010-12-07 18:44 ` Chris Mason
2010-12-07 19:16   ` Mike Fedyk
2010-12-07 19:29     ` Chris Mason
2010-12-07 20:07       ` Mike Fedyk
2010-12-07 20:15         ` Chris Mason
2010-12-07 22:06           ` Mike Fedyk
2010-12-08  0:15           ` Tsutomu Itoh

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