From: Andreas Dilger <adilger@dilger.ca>
To: Kazuya Mio <k-mio@sx.jp.nec.com>
Cc: ext4 <linux-ext4@vger.kernel.org>, Theodore Tso <tytso@mit.edu>,
linux-fsdevel@vger.kernel.org
Subject: Re: [RFC][PATCH V3 1/4] ext4: add EXT4_IOC_CONTROL_PA to create/discard inode PA
Date: Wed, 1 Dec 2010 03:14:20 -0700 [thread overview]
Message-ID: <62E660B4-8AF6-4B94-B3C0-1557ACA136DB@dilger.ca> (raw)
In-Reply-To: <4CF5E5F2.9080007@sx.jp.nec.com>
On 2010-11-30, at 23:06, Kazuya Mio wrote:
> EXT4_IOC_CONTROL_PA allows to create new inode PA based on the specified
> range, or to discard all inode PAs in the target inode.
>
> INTERFACE
> -----------
>
> #define EXT4_IOC_CONTROL_PA _IOWR('f', 16, struct ext4_prealloc_info)
>
> struct ext4_prealloc_info {
> __u64 pi_pstart; /* physical offset for the start of the PA from
> * the beginning of the file (in/out) */
> __u32 pi_lstart; /* logical offset for the start of the PA from
> * the beginning of the disk (in/out) */
Is the comment here wrong, or do I misunderstand that there is a 64-bit offset for the file, and only a 32-bit offset for the disk? It doesn't make sense to create a new API that only has a 32-bit offset for the disk, since ext4 is nearly supporting 64-bit filesystem blocks.
Looking at the patch, it seems that pi_pstart is indeed the physical offset, so it should be 64-bit, and it just appears that the comment is incorrect.
Cheers, Andreas
next prev parent reply other threads:[~2010-12-01 10:14 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-12-01 6:06 [RFC][PATCH V3 1/4] ext4: add EXT4_IOC_CONTROL_PA to create/discard inode PA Kazuya Mio
2010-12-01 10:14 ` Andreas Dilger [this message]
2010-12-02 6:07 ` Kazuya Mio
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