Return-Path: Received: from mail-ig0-f175.google.com ([209.85.213.175]:37975 "EHLO mail-ig0-f175.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753964AbbKBShU (ORCPT ); Mon, 2 Nov 2015 13:37:20 -0500 Received: by igbdj2 with SMTP id dj2so59882699igb.1 for ; Mon, 02 Nov 2015 10:37:20 -0800 (PST) From: Trond Myklebust Message-ID: <1446489215.30323.0.camel@primarydata.com> Mime-Version: 1.0 Subject: [PATCH 1/2] pNFS/flexfiles: When mirrored, retry failed reads by switching mirrors Date: Mon, 02 Nov 2015 13:37:07 -0500 Sender: linux-nfs-owner@vger.kernel.org List-ID: To: unlisted-recipients:; (no To-header on input)@mail.corp.redhat.com If the pNFS/flexfiles file is mirrored, and a read to one mirror fails, then we should bump the mirror index, so that we retry to a different mirror. Once we've iterated through all mirrors and all failed, we can return the layout and issue a new LAYOUTGET. Signed-off-by: Trond Myklebust --- fs/nfs/flexfilelayout/flexfilelayout.c | 22 ++++++++++++++-------- 1 file changed, 14 insertions(+), 8 deletions(-) diff --git a/fs/nfs/flexfilelayout/flexfilelayout.c b/fs/nfs/flexfilelayout= /flexfilelayout.c index fbc5a56de875..7fc14b90886e 100644 --- a/fs/nfs/flexfilelayout/flexfilelayout.c +++ b/fs/nfs/flexfilelayout/flexfilelayout.c @@ -741,17 +741,17 @@ ff_layout_alloc_commit_info(struct pnfs_layout_segmen= t *lseg, } =20 static struct nfs4_pnfs_ds * -ff_layout_choose_best_ds_for_read(struct nfs_pageio_descriptor *pgio, +ff_layout_choose_best_ds_for_read(struct pnfs_layout_segment *lseg, + int start_idx, int *best_idx) { - struct nfs4_ff_layout_segment *fls; + struct nfs4_ff_layout_segment *fls =3D FF_LAYOUT_LSEG(lseg); struct nfs4_pnfs_ds *ds; int idx; =20 - fls =3D FF_LAYOUT_LSEG(pgio->pg_lseg); /* mirrors are sorted by efficiency */ - for (idx =3D 0; idx < fls->mirror_array_cnt; idx++) { - ds =3D nfs4_ff_layout_prepare_ds(pgio->pg_lseg, idx, false); + for (idx =3D start_idx; idx < fls->mirror_array_cnt; idx++) { + ds =3D nfs4_ff_layout_prepare_ds(lseg, idx, false); if (ds) { *best_idx =3D idx; return ds; @@ -782,7 +782,7 @@ ff_layout_pg_init_read(struct nfs_pageio_descriptor *pg= io, if (pgio->pg_lseg =3D=3D NULL) goto out_mds; =20 - ds =3D ff_layout_choose_best_ds_for_read(pgio, &ds_idx); + ds =3D ff_layout_choose_best_ds_for_read(pgio->pg_lseg, 0, &ds_idx); if (!ds) goto out_mds; mirror =3D FF_LAYOUT_COMP(pgio->pg_lseg, ds_idx); @@ -1171,6 +1171,10 @@ static int ff_layout_read_done_cb(struct rpc_task *t= ask, =20 switch (err) { case -NFS4ERR_RESET_TO_PNFS: + if (ff_layout_choose_best_ds_for_read(hdr->lseg, + hdr->pgio_mirror_idx + 1, + &hdr->pgio_mirror_idx)) + goto out_eagain; set_bit(NFS_LAYOUT_RETURN_BEFORE_CLOSE, &hdr->lseg->pls_layout->plh_flags); pnfs_read_resend_pnfs(hdr); @@ -1179,11 +1183,13 @@ static int ff_layout_read_done_cb(struct rpc_task *= task, ff_layout_reset_read(hdr); return task->tk_status; case -EAGAIN: - rpc_restart_call_prepare(task); - return -EAGAIN; + goto out_eagain; } =20 return 0; +out_eagain: + rpc_restart_call_prepare(task); + return -EAGAIN; } =20 static bool --=20 2.5.0