Commit 33344e0f authored by Trond Myklebust's avatar Trond Myklebust Committed by Anna Schumaker
Browse files

pNFS: Add tracking to limit the number of pNFS retries 



When the client is reading or writing using pNFS, and hits an error
on the DS, then it typically sends a LAYOUTERROR and/or LAYOUTRETURN
to the MDS, before redirtying the failed pages, and going for a new
round of reads/writebacks. The problem is that if the server has no
way to fix the DS, then we may need a way to interrupt this loop
after a set number of attempts have been made.
This patch adds an optional module parameter that allows the admin
to specify how many times to retry the read/writeback process before
failing with a fatal error.
The default behaviour is to retry forever.

Signed-off-by: default avatarTrond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: default avatarAnna Schumaker <Anna.Schumaker@Netapp.com>
parent 28b1d3f5

fs/nfs/direct.c

+7 −0
Original line number Diff line number Diff line
@@ -663,6 +663,8 @@ static void nfs_direct_write_reschedule(struct nfs_direct_req *dreq) 
	}



	list_for_each_entry_safe(req, tmp, &reqs, wb_list) {

		/* Bump the transmission count */

		req->wb_nio++;

		if (!nfs_pageio_add_request(&desc, req)) {

			nfs_list_move_request(req, &failed);

			spin_lock(&cinfo.inode->i_lock);
@@ -703,6 +705,11 @@ static void nfs_direct_commit_complete(struct nfs_commit_data *data) 
		req = nfs_list_entry(data->pages.next);

		nfs_list_remove_request(req);

		if (dreq->flags == NFS_ODIRECT_RESCHED_WRITES) {

			/*

			 * Despite the reboot, the write was successful,

			 * so reset wb_nio.

			 */

			req->wb_nio = 0;

			/* Note the rewrite will go through mds */

			nfs_mark_request_commit(req, NULL, &cinfo, 0);

		} else

fs/nfs/flexfilelayout/flexfilelayout.c

+8 −0
Original line number Diff line number Diff line
@@ -28,6 +28,8 @@ 
#define FF_LAYOUT_POLL_RETRY_MAX     (15*HZ)

#define FF_LAYOUTRETURN_MAXERR 20



static unsigned short io_maxretrans;



static void ff_layout_read_record_layoutstats_done(struct rpc_task *task,

		struct nfs_pgio_header *hdr);

static int ff_layout_mirror_prepare_stats(struct pnfs_layout_hdr *lo,
@@ -925,6 +927,7 @@ retry: 
	pgm = &pgio->pg_mirrors[0];

	pgm->pg_bsize = mirror->mirror_ds->ds_versions[0].rsize;



	pgio->pg_maxretrans = io_maxretrans;

	return;

out_nolseg:

	if (pgio->pg_error < 0)
@@ -992,6 +995,7 @@ retry: 
		pgm->pg_bsize = mirror->mirror_ds->ds_versions[0].wsize;

	}



	pgio->pg_maxretrans = io_maxretrans;

	return;



out_mds:
@@ -2515,3 +2519,7 @@ MODULE_DESCRIPTION("The NFSv4 flexfile layout driver"); 


module_init(nfs4flexfilelayout_init);

module_exit(nfs4flexfilelayout_exit);



module_param(io_maxretrans, ushort, 0644);

MODULE_PARM_DESC(io_maxretrans, "The  number of times the NFSv4.1 client "

			"retries an I/O request before returning an error. ");

fs/nfs/pagelist.c

+13 −1
Original line number Diff line number Diff line
@@ -16,8 +16,8 @@ 
#include <linux/nfs.h>

#include <linux/nfs3.h>

#include <linux/nfs4.h>

#include <linux/nfs_page.h>

#include <linux/nfs_fs.h>

#include <linux/nfs_page.h>

#include <linux/nfs_mount.h>

#include <linux/export.h>
@@ -327,6 +327,7 @@ __nfs_create_request(struct nfs_lock_context *l_ctx, struct page *page, 
	req->wb_bytes   = count;

	req->wb_context = get_nfs_open_context(ctx);

	kref_init(&req->wb_kref);

	req->wb_nio = 0;

	return req;

}
@@ -370,6 +371,7 @@ nfs_create_subreq(struct nfs_page *req, struct nfs_page *last, 
		nfs_lock_request(ret);

		ret->wb_index = req->wb_index;

		nfs_page_group_init(ret, last);

		ret->wb_nio = req->wb_nio;

	}

	return ret;

}
@@ -724,6 +726,7 @@ void nfs_pageio_init(struct nfs_pageio_descriptor *desc, 
	desc->pg_mirrors_dynamic = NULL;

	desc->pg_mirrors = desc->pg_mirrors_static;

	nfs_pageio_mirror_init(&desc->pg_mirrors[0], bsize);

	desc->pg_maxretrans = 0;

}



/**
@@ -983,6 +986,15 @@ static int nfs_pageio_do_add_request(struct nfs_pageio_descriptor *desc, 
			return 0;

		mirror->pg_base = req->wb_pgbase;

	}



	if (desc->pg_maxretrans && req->wb_nio > desc->pg_maxretrans) {

		if (NFS_SERVER(desc->pg_inode)->flags & NFS_MOUNT_SOFTERR)

			desc->pg_error = -ETIMEDOUT;

		else

			desc->pg_error = -EIO;

		return 0;

	}



	if (!nfs_can_coalesce_requests(prev, req, desc))

		return 0;

	nfs_list_move_request(req, &mirror->pg_list);

fs/nfs/write.c

+5 −0
Original line number Diff line number Diff line
@@ -1009,6 +1009,8 @@ static void nfs_write_completion(struct nfs_pgio_header *hdr) 
			goto remove_req;

		}

		if (nfs_write_need_commit(hdr)) {

			/* Reset wb_nio, since the write was successful. */

			req->wb_nio = 0;

			memcpy(&req->wb_verf, &hdr->verf.verifier, sizeof(req->wb_verf));

			nfs_mark_request_commit(req, hdr->lseg, &cinfo,

				hdr->pgio_mirror_idx);
@@ -1142,6 +1144,7 @@ static struct nfs_page *nfs_try_to_update_request(struct inode *inode, 
		req->wb_bytes = end - req->wb_offset;

	else

		req->wb_bytes = rqend - req->wb_offset;

	req->wb_nio = 0;

	return req;

out_flushme:

	/*
@@ -1416,6 +1419,8 @@ static void nfs_initiate_write(struct nfs_pgio_header *hdr, 
 */

static void nfs_redirty_request(struct nfs_page *req)

{

	/* Bump the transmission count */

	req->wb_nio++;

	nfs_mark_request_dirty(req);

	set_bit(NFS_CONTEXT_RESEND_WRITES, &req->wb_context->flags);

	nfs_end_page_writeback(req);

include/linux/nfs_page.h

+3 −1
Original line number Diff line number Diff line
@@ -53,6 +53,7 @@ struct nfs_page { 
	struct nfs_write_verifier	wb_verf;	/* Commit cookie */

	struct nfs_page		*wb_this_page;  /* list of reqs for this page */

	struct nfs_page		*wb_head;       /* head pointer for req list */

	unsigned short		wb_nio;		/* Number of I/O attempts */

};



struct nfs_pageio_descriptor;
@@ -87,7 +88,6 @@ struct nfs_pgio_mirror { 
};



struct nfs_pageio_descriptor {

	unsigned char		pg_moreio : 1;

	struct inode		*pg_inode;

	const struct nfs_pageio_ops *pg_ops;

	const struct nfs_rw_ops *pg_rw_ops;
@@ -105,6 +105,8 @@ struct nfs_pageio_descriptor { 
	struct nfs_pgio_mirror	pg_mirrors_static[1];

	struct nfs_pgio_mirror	*pg_mirrors_dynamic;

	u32			pg_mirror_idx;	/* current mirror */

	unsigned short		pg_maxretrans;

	unsigned char		pg_moreio : 1;

};



/* arbitrarily selected limit to number of mirrors */

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