Commit 64294b08 authored by Trond Myklebust's avatar Trond Myklebust Committed by Trond Myklebust

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: default avatarTrond Myklebust <trond.myklebust@hammerspace.com>
parent 8dc96566
...@@ -2046,6 +2046,11 @@ static void _lgopen_prepare_attached(struct nfs4_opendata *data, ...@@ -2046,6 +2046,11 @@ static void _lgopen_prepare_attached(struct nfs4_opendata *data,
struct nfs4_layoutget *lgp; struct nfs4_layoutget *lgp;
struct pnfs_layout_hdr *lo; 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); lo = _pnfs_grab_empty_layout(ino, ctx);
if (!lo) if (!lo)
return; return;
......
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