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Commit 76c66905 authored by Trond Myklebust's avatar Trond Myklebust
Browse files

NFS/flexfiles: Speed up read failover when DSes are down 



If we notice that a DS may be down, we should attempt to read from the
other mirrors first before we go back to retry the dead DS.

Signed-off-by: default avatarTrond Myklebust <trond.myklebust@hammerspace.com>
parent 17aaec81

fs/nfs/flexfilelayout/flexfilelayout.c

+62 −12
Original line number Diff line number Diff line
@@ -788,10 +788,28 @@ ff_layout_alloc_commit_info(struct pnfs_layout_segment *lseg, 
	}

}



static void

ff_layout_mark_ds_unreachable(struct pnfs_layout_segment *lseg, int idx)

{

	struct nfs4_deviceid_node *devid = FF_LAYOUT_DEVID_NODE(lseg, idx);



	if (devid)

		nfs4_mark_deviceid_unavailable(devid);

}



static void

ff_layout_mark_ds_reachable(struct pnfs_layout_segment *lseg, int idx)

{

	struct nfs4_deviceid_node *devid = FF_LAYOUT_DEVID_NODE(lseg, idx);



	if (devid)

		nfs4_mark_deviceid_available(devid);

}



static struct nfs4_pnfs_ds *

ff_layout_choose_best_ds_for_read(struct pnfs_layout_segment *lseg,

				  int start_idx,

				  int *best_idx)

ff_layout_choose_ds_for_read(struct pnfs_layout_segment *lseg,

			     int start_idx, int *best_idx,

			     bool check_device)

{

	struct nfs4_ff_layout_segment *fls = FF_LAYOUT_LSEG(lseg);

	struct nfs4_ff_layout_mirror *mirror;
@@ -799,25 +817,53 @@ ff_layout_choose_best_ds_for_read(struct pnfs_layout_segment *lseg, 
	bool fail_return = false;

	int idx;



	/* mirrors are sorted by efficiency */

	/* mirrors are initially sorted by efficiency */

	for (idx = start_idx; idx < fls->mirror_array_cnt; idx++) {

		if (idx+1 == fls->mirror_array_cnt)

			fail_return = true;

			fail_return = !check_device;



		mirror = FF_LAYOUT_COMP(lseg, idx);

		if (ff_layout_test_devid_unavailable(&mirror->mirror_ds->id_node))

		ds = nfs4_ff_layout_prepare_ds(lseg, mirror, fail_return);

		if (!ds)

			continue;



		if (check_device &&

		    nfs4_test_deviceid_unavailable(&mirror->mirror_ds->id_node))

			continue;



		ds = nfs4_ff_layout_prepare_ds(lseg, mirror, fail_return);

		if (ds) {

		*best_idx = idx;

		return ds;

	}

	}



	return NULL;

}



static struct nfs4_pnfs_ds *

ff_layout_choose_any_ds_for_read(struct pnfs_layout_segment *lseg,

				 int start_idx, int *best_idx)

{

	return ff_layout_choose_ds_for_read(lseg, start_idx, best_idx, false);

}



static struct nfs4_pnfs_ds *

ff_layout_choose_valid_ds_for_read(struct pnfs_layout_segment *lseg,

				   int start_idx, int *best_idx)

{

	return ff_layout_choose_ds_for_read(lseg, start_idx, best_idx, true);

}



static struct nfs4_pnfs_ds *

ff_layout_choose_best_ds_for_read(struct pnfs_layout_segment *lseg,

				  int start_idx, int *best_idx)

{

	struct nfs4_pnfs_ds *ds;



	ds = ff_layout_choose_valid_ds_for_read(lseg, start_idx, best_idx);

	if (ds)

		return ds;

	return ff_layout_choose_any_ds_for_read(lseg, start_idx, best_idx);

}



static void

ff_layout_pg_get_read(struct nfs_pageio_descriptor *pgio,

		      struct nfs_page *req,
@@ -1167,8 +1213,10 @@ static int ff_layout_async_handle_error(struct rpc_task *task, 
{

	int vers = clp->cl_nfs_mod->rpc_vers->number;



	if (task->tk_status >= 0)

	if (task->tk_status >= 0) {

		ff_layout_mark_ds_reachable(lseg, idx);

		return 0;

	}



	/* Handle the case of an invalid layout segment */

	if (!pnfs_is_valid_lseg(lseg))
@@ -1231,6 +1279,8 @@ static void ff_layout_io_track_ds_error(struct pnfs_layout_segment *lseg, 
	err = ff_layout_track_ds_error(FF_LAYOUT_FROM_HDR(lseg->pls_layout),

				       mirror, offset, length, status, opnum,

				       GFP_NOIO);

	if (status == NFS4ERR_NXIO)

		ff_layout_mark_ds_unreachable(lseg, idx);

	pnfs_error_mark_layout_for_return(lseg->pls_layout->plh_inode, lseg);

	dprintk("%s: err %d op %d status %u\n", __func__, err, opnum, status);

}

fs/nfs/pnfs.h

+1 −0
Original line number Diff line number Diff line
@@ -350,6 +350,7 @@ void nfs4_delete_deviceid(const struct pnfs_layoutdriver_type *, const struct nf 
void nfs4_init_deviceid_node(struct nfs4_deviceid_node *, struct nfs_server *,

			     const struct nfs4_deviceid *);

bool nfs4_put_deviceid_node(struct nfs4_deviceid_node *);

void nfs4_mark_deviceid_available(struct nfs4_deviceid_node *node);

void nfs4_mark_deviceid_unavailable(struct nfs4_deviceid_node *node);

bool nfs4_test_deviceid_unavailable(struct nfs4_deviceid_node *node);

void nfs4_deviceid_purge_client(const struct nfs_client *);

fs/nfs/pnfs_dev.c

+10 −0
Original line number Diff line number Diff line
@@ -283,6 +283,16 @@ nfs4_put_deviceid_node(struct nfs4_deviceid_node *d) 
}

EXPORT_SYMBOL_GPL(nfs4_put_deviceid_node);



void

nfs4_mark_deviceid_available(struct nfs4_deviceid_node *node)

{

	if (test_bit(NFS_DEVICEID_UNAVAILABLE, &node->flags)) {

		clear_bit(NFS_DEVICEID_UNAVAILABLE, &node->flags);

		smp_mb__after_atomic();

	}

}

EXPORT_SYMBOL_GPL(nfs4_mark_deviceid_available);



void

nfs4_mark_deviceid_unavailable(struct nfs4_deviceid_node *node)

{