On wed, 08 Dec 2010 08:53:55 +0900, Tsutomu Itoh wrote:
>>> 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...
Several months ago, some one posted a patch to get the allocated size of the
compressed file,
http://marc.info/?l=linux-btrfs&m=128109745012238&w=2
this patch may help you to implement what you need.
Regards
Miao
>>
>>>
>>> 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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