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: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
---
fs/nfs/direct.c | 7 +++++++
fs/nfs/flexfilelayout/flexfilelayout.c | 8 ++++++++
fs/nfs/pagelist.c | 14 +++++++++++++-
fs/nfs/write.c | 5 +++++
include/linux/nfs_page.h | 4 +++-
5 files changed, 36 insertions(+), 2 deletions(-)
diff --git a/fs/nfs/direct.c b/fs/nfs/direct.c
index 2d301a1a73e2..2436bd92bc00 100644
--- a/fs/nfs/direct.c
+++ b/fs/nfs/direct.c
@@ -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
diff --git a/fs/nfs/flexfilelayout/flexfilelayout.c b/fs/nfs/flexfilelayout/flexfilelayout.c
index 6673d4ff5a2a..9fdbcfd3e39d 100644
--- a/fs/nfs/flexfilelayout/flexfilelayout.c
+++ b/fs/nfs/flexfilelayout/flexfilelayout.c
@@ -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 @@ ff_layout_pg_init_read(struct nfs_pageio_descriptor *pgio,
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 @@ ff_layout_pg_init_write(struct nfs_pageio_descriptor *pgio,
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. ");
diff --git a/fs/nfs/pagelist.c b/fs/nfs/pagelist.c
index b8301c40dd78..4a31284f411e 100644
--- a/fs/nfs/pagelist.c
+++ b/fs/nfs/pagelist.c
@@ -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);
diff --git a/fs/nfs/write.c b/fs/nfs/write.c
index 0712d886ff08..908b166d635d 100644
--- a/fs/nfs/write.c
+++ b/fs/nfs/write.c
@@ -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);
diff --git a/include/linux/nfs_page.h b/include/linux/nfs_page.h
index b7d0f15615c2..8b36800d342d 100644
--- a/include/linux/nfs_page.h
+++ b/include/linux/nfs_page.h
@@ -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 */
--
2.20.1
