From 260074cd8413489903d4484058e61649d6e08580 Mon Sep 17 00:00:00 2001 From: Trond Myklebust Date: Mon, 2 Nov 2015 09:59:00 -0500 Subject: [PATCH] pNFS/flexfiles: Add support for FF_FLAGS_NO_IO_THRU_MDS For loosely coupled pNFS/flexfiles systems, there is often no advantage at all in going through the MDS for I/O, since the MDS is subject to the same limitations as all other clients when talking to DSes. If a DS is unresponsive, I/O through the MDS will fail. For such systems, the only scalable solution is to have the pNFS clients retry doing pNFS, and so the protocol now provides a flag that allows the pNFS server to signal this. If LAYOUTGET returns FF_FLAGS_NO_IO_THRU_MDS, then we should assume that the MDS wants the client to retry using these devices, even if they were previously marked as being unavailable. To do so, we add a helper, ff_layout_mark_devices_valid() that will be called from layoutget. Signed-off-by: Trond Myklebust --- fs/nfs/flexfilelayout/flexfilelayout.c | 18 ++++++++++++++++-- fs/nfs/flexfilelayout/flexfilelayout.h | 7 +++++++ 2 files changed, 23 insertions(+), 2 deletions(-) diff --git a/fs/nfs/flexfilelayout/flexfilelayout.c b/fs/nfs/flexfilelayout/flexfilelayout.c index 7fc14b90886e..03516c80855a 100644 --- a/fs/nfs/flexfilelayout/flexfilelayout.c +++ b/fs/nfs/flexfilelayout/flexfilelayout.c @@ -339,6 +339,19 @@ static void ff_layout_sort_mirrors(struct nfs4_ff_layout_segment *fls) } } +static void ff_layout_mark_devices_valid(struct nfs4_ff_layout_segment *fls) +{ + struct nfs4_deviceid_node *node; + int i; + + if (!(fls->flags & FF_FLAGS_NO_IO_THRU_MDS)) + return; + for (i = 0; i < fls->mirror_array_cnt; i++) { + node = &fls->mirror_array[i]->mirror_ds->id_node; + clear_bit(NFS_DEVICEID_UNAVAILABLE, &node->flags); + } +} + static struct pnfs_layout_segment * ff_layout_alloc_lseg(struct pnfs_layout_hdr *lh, struct nfs4_layoutget_res *lgr, @@ -499,6 +512,7 @@ ff_layout_alloc_lseg(struct pnfs_layout_hdr *lh, rc = ff_layout_check_layout(lgr); if (rc) goto out_err_free; + ff_layout_mark_devices_valid(fls); ret = &fls->generic_hdr; dprintk("<-- %s (success)\n", __func__); @@ -1035,7 +1049,8 @@ static int ff_layout_async_handle_error_v4(struct rpc_task *task, rpc_wake_up(&tbl->slot_tbl_waitq); /* fall through */ default: - if (ff_layout_has_available_ds(lseg)) + if (ff_layout_no_fallback_to_mds(lseg) || + ff_layout_has_available_ds(lseg)) return -NFS4ERR_RESET_TO_PNFS; reset: dprintk("%s Retry through MDS. Error %d\n", __func__, @@ -1153,7 +1168,6 @@ static void ff_layout_io_track_ds_error(struct pnfs_layout_segment *lseg, } /* NFS_PROTO call done callback routines */ - static int ff_layout_read_done_cb(struct rpc_task *task, struct nfs_pgio_header *hdr) { diff --git a/fs/nfs/flexfilelayout/flexfilelayout.h b/fs/nfs/flexfilelayout/flexfilelayout.h index 68cc0d9828f9..2bb08bc6aaf0 100644 --- a/fs/nfs/flexfilelayout/flexfilelayout.h +++ b/fs/nfs/flexfilelayout/flexfilelayout.h @@ -10,6 +10,7 @@ #define FS_NFS_NFS4FLEXFILELAYOUT_H #define FF_FLAGS_NO_LAYOUTCOMMIT 1 +#define FF_FLAGS_NO_IO_THRU_MDS 2 #include "../pnfs.h" @@ -145,6 +146,12 @@ FF_LAYOUT_MIRROR_COUNT(struct pnfs_layout_segment *lseg) return FF_LAYOUT_LSEG(lseg)->mirror_array_cnt; } +static inline bool +ff_layout_no_fallback_to_mds(struct pnfs_layout_segment *lseg) +{ + return FF_LAYOUT_LSEG(lseg)->flags & FF_FLAGS_NO_IO_THRU_MDS; +} + static inline bool ff_layout_test_devid_unavailable(struct nfs4_deviceid_node *node) { -- 2.39.2