From 64294b08f9d27f83cbb0975250614864fa733bda Mon Sep 17 00:00:00 2001 From: Trond Myklebust Date: Thu, 2 Feb 2017 12:26:38 -0500 Subject: pNFS: Don't send LAYOUTGET on OPEN for read, if we already have cached data If we're only opening the file for reading, and the file is empty and/or we already have cached data, then heuristically optimise away the LAYOUTGET. Signed-off-by: Trond Myklebust --- fs/nfs/pnfs.c | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'fs') diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c index d5dc97f72b30..717cd95a0306 100644 --- a/fs/nfs/pnfs.c +++ b/fs/nfs/pnfs.c @@ -2046,6 +2046,11 @@ static void _lgopen_prepare_attached(struct nfs4_opendata *data, struct nfs4_layoutget *lgp; struct pnfs_layout_hdr *lo; + /* Heuristic: don't send layoutget if we have cached data */ + if (rng.iomode == IOMODE_READ && + (i_size_read(ino) == 0 || ino->i_mapping->nrpages != 0)) + return; + lo = _pnfs_grab_empty_layout(ino, ctx); if (!lo) return; -- cgit v1.2.3-59-g8ed1b