Re: [PATCH] Writeback page range hint

[Dave Jones <davej@redhat.com>]

On Mon, Aug 23, 2004 at 07:59:27PM +0000, Linux Kernel wrote:
 > ChangeSet 1.2034, 2004/08/23 12:59:27-07:00, akpm@osdl.org
 > 
 > 	[PATCH] Writeback page range hint
 > 	
 > 	Modify mpage_writepages to optionally only write back dirty pages within a
 > 	specified range in a file (as in the case of O_SYNC).  Cheat a little to avoid
 > 	changes to prototypes of aops - just put the <start, end> hint into the
 > 	writeback_control struct instead.  If <start, end> are not set, then default
 > 	to writing back all the mapping's dirty pages.

FYI, this chunk...

 >  	long pages_skipped;		/* Pages which were not written */
 > -	int nonblocking;		/* Don't get stuck on request queues */
 > -	int encountered_congestion;	/* An output: a queue is full */
 > -	int for_kupdate;		/* A kupdate writeback */
 > -	int for_reclaim;		/* Invoked from the page allocator */
 > +
 > +	/*
 > +	 * For a_ops->writepages(): is start or end are non-zero then this is
 > +	 * a hint that the filesystem need only write out the pages inside that
 > +	 * byterange.  The byte at `end' is included in the writeout request.
 > +	 */
 > +	loff_t start;
 > +	loff_t end;
 > +
 > +	int nonblocking:1;		/* Don't get stuck on request queues */
 > +	int encountered_congestion:1;	/* An output: a queue is full */
 > +	int for_kupdate:1;		/* A kupdate writeback */
 > +	int for_reclaim:1;		/* Invoked from the page allocator */

Causes sparse spew..

include/linux/writeback.h:54:19: warning: dubious one-bit signed bitfield
include/linux/writeback.h:55:30: warning: dubious one-bit signed bitfield
include/linux/writeback.h:56:19: warning: dubious one-bit signed bitfield
include/linux/writeback.h:57:19: warning: dubious one-bit signed bitfield

		Dave