This is a note to let you know that I've just added the patch titled pNFS/filelayout: Fix coalescing test for single DS to the 4.19-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: pnfs-filelayout-fix-coalescing-test-for-single-ds.patch and it can be found in the queue-4.19 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit ef7213b7afbb7a186d06ef515baf52a6540a5332 Author: Olga Kornievskaia <olga.kornievskaia@xxxxxxxxx> Date: Tue Dec 20 12:31:29 2022 -0500 pNFS/filelayout: Fix coalescing test for single DS [ Upstream commit a6b9d2fa0024e7e399c26facd0fb466b7396e2b9 ] 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@xxxxxxxxxx> Signed-off-by: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/fs/nfs/filelayout/filelayout.c b/fs/nfs/filelayout/filelayout.c index e8e825497cbd..015d39ac2c8f 100644 --- a/fs/nfs/filelayout/filelayout.c +++ b/fs/nfs/filelayout/filelayout.c @@ -837,6 +837,12 @@ 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() * @@ -857,6 +863,8 @@ 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) {