From: Wang Sheng-Hui <shhuiw@gmail.com>
To: Allison Henderson <achender@linux.vnet.ibm.com>,
Lukas Czerner <lczerner@redhat.com>,
Theodore Ts'o <tytso@mit.edu>,
linux-ext4@vger.kernel.org
Subject: One question about ext4_fallocate
Date: Thu, 19 Jul 2012 22:51:40 +0800 [thread overview]
Message-ID: <50081EFC.5060601@gmail.com> (raw)
Dear all,
I have one question about ext4_fallocate:
For its parameters, offset & len, it will preallocate
one space with length >= len, right?
>From the code:
map.m_lblk = offset >> blkbits;
/*
* We can't just convert len to max_blocks because
* If blocksize = 4096 offset = 3072 and len = 2048
*/
max_blocks = (EXT4_BLOCK_ALIGN(len + offset, blkbits) >> blkbits)
- map.m_lblk;
We can see that the target space is enlarged to the (floor, ceiling) of
(offset, offset+len). Right?
If I'm wrong, please correct me.
Regards,
next reply other threads:[~2012-07-19 14:51 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-07-19 14:51 Wang Sheng-Hui [this message]
2012-07-19 15:42 ` One question about ext4_fallocate Andreas Dilger
2012-07-20 6:39 ` Wang Sheng-Hui
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