Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 260074cd authored by Trond Myklebust's avatar Trond Myklebust
Browse files

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: default avatarTrond Myklebust <trond.myklebust@primarydata.com>
parent 13544412

fs/nfs/flexfilelayout/flexfilelayout.c

+16 −2
Original line number Diff line number Diff line
@@ -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)

{

fs/nfs/flexfilelayout/flexfilelayout.h

+7 −0
Original line number Diff line number Diff line
@@ -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)

{