Re: [PATCH 22/43] CacheFiles: Add a hook to write a single page ofdata to an inode [ver #46]

From: Christoph Hellwig
Date: Thu Apr 02 2009 - 12:37:36 EST


On Fri, Apr 03, 2009 at 02:32:58AM +1100, Nick Piggin wrote:
> Hmm, I guess not all filesystems define write_begin/write_end. But if you
> only need to use ones that do define them?

No. write_begin/write_end are simply callbacks for the write helpers,
and locking for them is entirely filesystem-defined. E.g. xfs and the
cluster filesystems require additional locks taken first, and some
network filesystems require inode revalidations first.

They really should be taken out of the address_space_operations and
passed as callbacks to generic_file_aio_write & co.

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