Commit 33ad5d54 authored Oct 29, 2014 by Bob Peterson Committed by Steven Whitehouse Nov 03, 2014

GFS2: Only increase rs_sizehint

If an application does a sequence of (1) big write, (2) little write
we don't necessarily want to reset the size hint based on the smaller
size. The fact that they did any big writes implies they may do more,
and therefore we should try to allocate bigger block reservations, even
if the last few were small writes. Therefore this patch changes function
gfs2_size_hint so that the size hint can only grow; it cannot shrink.
This is especially important where there are multiple writers.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

parent 0e27c18c

fs/gfs2/file.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -337,6 +337,7 @@ static void gfs2_size_hint(struct file *filep, loff_t offset, size_t size)
		size_t blks = (size + sdp->sd_sb.sb_bsize - 1) >> sdp->sd_sb.sb_bsize_shift;
		int hint = min_t(size_t, INT_MAX, blks);

		if (hint > atomic_read(&ip->i_res->rs_sizehint))
		atomic_set(&ip->i_res->rs_sizehint, hint);
		}

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