From: Christoph Hellwig <hch@infradead.org>
To: Dave Chinner <david@fromorbit.com>
Cc: Jerome Glisse <jglisse@redhat.com>,
lsf-pc@lists.linux-foundation.org, linux-mm@kvack.org,
linux-fsdevel@vger.kernel.org, linux-block@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [LSF/MM TOPIC] Direct block mapping through fs for device
Date: Fri, 26 Apr 2019 05:45:53 -0700 [thread overview]
Message-ID: <20190426124553.GB12339@infradead.org> (raw)
In-Reply-To: <20190426062816.GG1454@dread.disaster.area>
On Fri, Apr 26, 2019 at 04:28:16PM +1000, Dave Chinner wrote:
> i.e. go look at how xfs_pnfs.c works to hand out block mappings to
> remote pNFS clients so they can directly access the underlying
> storage. Basically, anyone wanting to map blocks needs a file layout
> lease and then to manage the filesystem state over that range via
> these methods in the struct export_operations:
>
> int (*get_uuid)(struct super_block *sb, u8 *buf, u32 *len, u64 *offset);
> int (*map_blocks)(struct inode *inode, loff_t offset,
> u64 len, struct iomap *iomap,
> bool write, u32 *device_generation);
> int (*commit_blocks)(struct inode *inode, struct iomap *iomaps,
> int nr_iomaps, struct iattr *iattr);
Nipick: get_uuid isn't needed for the least itself, it just works
around the fact that the original pNFS/block protocol is braindead.
The pNFS/SCSI prototocol already switches to a device UUID, and other
users that work locally shouldn't need it either.
next prev parent reply other threads:[~2019-04-26 12:45 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-26 1:38 [LSF/MM TOPIC] Direct block mapping through fs for device Jerome Glisse
2019-04-26 6:28 ` Dave Chinner
2019-04-26 12:45 ` Christoph Hellwig [this message]
2019-04-26 14:45 ` Darrick J. Wong
2019-04-26 14:47 ` Christoph Hellwig
2019-04-26 15:20 ` Jerome Glisse
2019-04-27 1:25 ` Dave Chinner
2019-04-29 13:26 ` Jerome Glisse
2019-05-01 23:47 ` Dave Chinner
2019-05-02 1:52 ` Matthew Wilcox
2019-04-26 20:28 ` Adam Manzanares
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