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Commit 22905f77 authored by Andrew Morton's avatar Andrew Morton Committed by Trond Myklebust
Browse files

identify multipage ->writepages() calls 



 NFS needs to be able to distinguish between single-page ->writepage() calls and
 multipage ->writepages() calls.

 For the single-page writepage calls NFS can kick off the I/O within the
 context of ->writepage().

 For multipage ->writepages calls, nfs_writepage() will leave the I/O pending
 and nfs_writepages() will kick off the I/O when it all has been queued up
 within NFS.

 Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
 Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
 Signed-off-by: default avatarTrond Myklebust <Trond.Myklebust@netapp.com>
parent d99cf9d6

include/linux/writeback.h

+5 −4
Original line number Diff line number Diff line
@@ -57,6 +57,7 @@ struct writeback_control { 
	unsigned encountered_congestion:1; /* An output: a queue is full */

	unsigned for_kupdate:1;		/* A kupdate writeback */

	unsigned for_reclaim:1;		/* Invoked from the page allocator */

	unsigned for_writepages:1;	/* This is a writepages() call */

};



/*

mm/page-writeback.c

+8 −2
Original line number Diff line number Diff line
@@ -550,11 +550,17 @@ void __init page_writeback_init(void) 


int do_writepages(struct address_space *mapping, struct writeback_control *wbc)

{

	int ret;



	if (wbc->nr_to_write <= 0)

		return 0;

	wbc->for_writepages = 1;

	if (mapping->a_ops->writepages)

		return mapping->a_ops->writepages(mapping, wbc);

	return generic_writepages(mapping, wbc);

		ret =  mapping->a_ops->writepages(mapping, wbc);

	else

		ret = generic_writepages(mapping, wbc);

	wbc->for_writepages = 0;

	return ret;

}



/**