[PATCH 1/3] pNFS/flexfiles: Fix list corruption if the mirror count changes

[PATCH 1/3] pNFS/flexfiles: Fix list corruption if the mirror count changes

[trondmy]

From: Trond Myklebust <trond.myklebust@hammerspace.com>

If the mirror count changes in the new layout we pick up inside
ff_layout_pg_init_write(), then we can end up adding the
request to the wrong mirror and corrupting the mirror->pg_list.

Fixes: d600ad1f2bdb ("NFS41: pop some layoutget errors to application")
Cc: stable@vger.kernel.org
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
---
 fs/nfs/flexfilelayout/flexfilelayout.c | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/fs/nfs/flexfilelayout/flexfilelayout.c b/fs/nfs/flexfilelayout/flexfilelayout.c
index 7d399f72ebbb..de03e440b7ee 100644
--- a/fs/nfs/flexfilelayout/flexfilelayout.c
+++ b/fs/nfs/flexfilelayout/flexfilelayout.c
@@ -907,9 +907,8 @@ ff_layout_pg_init_write(struct nfs_pageio_descriptor *pgio,
 		goto out_mds;
 
 	/* Use a direct mapping of ds_idx to pgio mirror_idx */
-	if (WARN_ON_ONCE(pgio->pg_mirror_count !=
-	    FF_LAYOUT_MIRROR_COUNT(pgio->pg_lseg)))
-		goto out_mds;
+	if (pgio->pg_mirror_count != FF_LAYOUT_MIRROR_COUNT(pgio->pg_lseg))
+		goto out_eagain;
 
 	for (i = 0; i < pgio->pg_mirror_count; i++) {
 		mirror = FF_LAYOUT_COMP(pgio->pg_lseg, i);
@@ -931,7 +930,10 @@ ff_layout_pg_init_write(struct nfs_pageio_descriptor *pgio,
 			(NFS_MOUNT_SOFT|NFS_MOUNT_SOFTERR))
 		pgio->pg_maxretrans = io_maxretrans;
 	return;
-
+out_eagain:
+	pnfs_generic_pg_cleanup(pgio);
+	pgio->pg_error = -EAGAIN;
+	return;
 out_mds:
 	trace_pnfs_mds_fallback_pg_init_write(pgio->pg_inode,
 			0, NFS4_MAX_UINT64, IOMODE_RW,
@@ -941,6 +943,7 @@ ff_layout_pg_init_write(struct nfs_pageio_descriptor *pgio,
 	pgio->pg_lseg = NULL;
 	pgio->pg_maxretrans = 0;
 	nfs_pageio_reset_write_mds(pgio);
+	pgio->pg_error = -EAGAIN;
 }
 
 static unsigned int
-- 
2.26.2

[PATCH 2/3] pNFS/flexfiles: Clean up redundant calls to pnfs_put_lseg()

[trondmy]

From: Trond Myklebust <trond.myklebust@hammerspace.com>

Both nfs_pageio_reset_read_mds() and nfs_pageio_reset_write_mds()
do call pnfs_generic_pg_cleanup() for us.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
---
 fs/nfs/flexfilelayout/flexfilelayout.c | 10 ++--------
 1 file changed, 2 insertions(+), 8 deletions(-)

diff --git a/fs/nfs/flexfilelayout/flexfilelayout.c b/fs/nfs/flexfilelayout/flexfilelayout.c
index de03e440b7ee..b3ec12e5fde1 100644
--- a/fs/nfs/flexfilelayout/flexfilelayout.c
+++ b/fs/nfs/flexfilelayout/flexfilelayout.c
@@ -844,8 +844,7 @@ ff_layout_pg_init_read(struct nfs_pageio_descriptor *pgio,
 	if (!ds) {
 		if (!ff_layout_no_fallback_to_mds(pgio->pg_lseg))
 			goto out_mds;
-		pnfs_put_lseg(pgio->pg_lseg);
-		pgio->pg_lseg = NULL;
+		pnfs_generic_pg_cleanup(pgio);
 		/* Sleep for 1 second before retrying */
 		ssleep(1);
 		goto retry;
@@ -871,8 +870,6 @@ ff_layout_pg_init_read(struct nfs_pageio_descriptor *pgio,
 			0, NFS4_MAX_UINT64, IOMODE_READ,
 			NFS_I(pgio->pg_inode)->layout,
 			pgio->pg_lseg);
-	pnfs_put_lseg(pgio->pg_lseg);
-	pgio->pg_lseg = NULL;
 	pgio->pg_maxretrans = 0;
 	nfs_pageio_reset_read_mds(pgio);
 }
@@ -916,8 +913,7 @@ ff_layout_pg_init_write(struct nfs_pageio_descriptor *pgio,
 		if (!ds) {
 			if (!ff_layout_no_fallback_to_mds(pgio->pg_lseg))
 				goto out_mds;
-			pnfs_put_lseg(pgio->pg_lseg);
-			pgio->pg_lseg = NULL;
+			pnfs_generic_pg_cleanup(pgio);
 			/* Sleep for 1 second before retrying */
 			ssleep(1);
 			goto retry;
@@ -939,8 +935,6 @@ ff_layout_pg_init_write(struct nfs_pageio_descriptor *pgio,
 			0, NFS4_MAX_UINT64, IOMODE_RW,
 			NFS_I(pgio->pg_inode)->layout,
 			pgio->pg_lseg);
-	pnfs_put_lseg(pgio->pg_lseg);
-	pgio->pg_lseg = NULL;
 	pgio->pg_maxretrans = 0;
 	nfs_pageio_reset_write_mds(pgio);
 	pgio->pg_error = -EAGAIN;
-- 
2.26.2

[PATCH 3/3] pNFS/flexfiles: The mirror count could depend on the layout segment range

[trondmy]

From: Trond Myklebust <trond.myklebust@hammerspace.com>

Make sure we specify the layout segment range when calculating the
mirror count. In theory, that number could depend on the range to
which we're writing.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
---
 fs/nfs/flexfilelayout/flexfilelayout.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/fs/nfs/flexfilelayout/flexfilelayout.c b/fs/nfs/flexfilelayout/flexfilelayout.c
index b3ec12e5fde1..b26173d72735 100644
--- a/fs/nfs/flexfilelayout/flexfilelayout.c
+++ b/fs/nfs/flexfilelayout/flexfilelayout.c
@@ -947,8 +947,8 @@ ff_layout_pg_get_mirror_count_write(struct nfs_pageio_descriptor *pgio,
 	if (!pgio->pg_lseg) {
 		pgio->pg_lseg = pnfs_update_layout(pgio->pg_inode,
 						   nfs_req_openctx(req),
-						   0,
-						   NFS4_MAX_UINT64,
+						   req_offset(req),
+						   req->wb_bytes,
 						   IOMODE_RW,
 						   false,
 						   GFP_NOFS);
-- 
2.26.2