From: Olga Kornievskaia <olga.kornievskaia@gmail.com>
Date: Tue, 20 Dec 2022 17:31:29 +0000 (-0500)
Subject: pNFS/filelayout: Fix coalescing test for single DS
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=a6b9d2fa0024e7e399c26facd0fb466b7396e2b9;p=linux.git

pNFS/filelayout: Fix coalescing test for single DS

When there is a single DS no striping constraints need to be placed on
the IO. When such constraint is applied then buffered reads don't
coalesce to the DS's rsize.

Signed-off-by: Olga Kornievskaia <kolga@netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
---

diff --git a/fs/nfs/filelayout/filelayout.c b/fs/nfs/filelayout/filelayout.c
index ad34a33b0737c..4974cd18ca468 100644
--- a/fs/nfs/filelayout/filelayout.c
+++ b/fs/nfs/filelayout/filelayout.c
@@ -783,6 +783,12 @@ filelayout_alloc_lseg(struct pnfs_layout_hdr *layoutid,
 	return &fl->generic_hdr;
 }
 
+static bool
+filelayout_lseg_is_striped(const struct nfs4_filelayout_segment *flseg)
+{
+	return flseg->num_fh > 1;
+}
+
 /*
  * filelayout_pg_test(). Called by nfs_can_coalesce_requests()
  *
@@ -803,6 +809,8 @@ filelayout_pg_test(struct nfs_pageio_descriptor *pgio, struct nfs_page *prev,
 	size = pnfs_generic_pg_test(pgio, prev, req);
 	if (!size)
 		return 0;
+	else if (!filelayout_lseg_is_striped(FILELAYOUT_LSEG(pgio->pg_lseg)))
+		return size;
 
 	/* see if req and prev are in the same stripe */
 	if (prev) {