FAILED: patch "[PATCH] nfsd: reset write verifier on deferred writeback errors" failed to apply to 6.1-stable tree

FAILED: patch "[PATCH] nfsd: reset write verifier on deferred writeback errors" failed to apply to 6.1-stable tree

[gregkh]

The patch below does not apply to the 6.1-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.1.y
git checkout FETCH_HEAD
git cherry-pick -x 2090b05803faab8a9fa62fbff871007862cac1b7
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2026070204-congress-elope-c3c1@gregkh' --subject-prefix 'PATCH 6.1.y' 'HEAD^..'

Possible dependencies:



thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 2090b05803faab8a9fa62fbff871007862cac1b7 Mon Sep 17 00:00:00 2001
From: Jeff Layton <jlayton@kernel.org>
Date: Fri, 22 May 2026 12:44:19 -0400
Subject: [PATCH] nfsd: reset write verifier on deferred writeback errors
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

nfsd_vfs_write() and nfsd_commit() both call filemap_check_wb_err() to
detect deferred writeback errors, but neither rotates the server's write
verifier (nn->writeverf) when this check fails. Every other
durable-storage-failure path in these functions calls
commit_reset_write_verifier() before returning an error.

The missing rotation means clients holding UNSTABLE write data under the
current verifier will COMMIT, receive the unchanged verifier back, and
conclude their data is durable — silently dropping data that failed
writeback. This violates the UNSTABLE+COMMIT durability contract
(RFC 1813 §3.3.7, RFC 8881 §18.32).

Add commit_reset_write_verifier() calls at both filemap_check_wb_err()
error sites, matching the pattern used by adjacent error paths in the
same functions. The helper already filters -EAGAIN and -ESTALE
internally, so the calls are unconditionally safe.

Reported-by: Chris Mason <clm@meta.com>
Fixes: 555dbf1a9aac ("nfsd: Replace use of rwsem with errseq_t")
Cc: stable@vger.kernel.org
Assisted-by: kres:claude-opus-4-6
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
index cba473969429..7e6468bdc723 100644
--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -1513,8 +1513,10 @@ nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp,
 	nfsd_stats_io_write_add(nn, exp, *cnt);
 	fsnotify_modify(file);
 	host_err = filemap_check_wb_err(file->f_mapping, since);
-	if (host_err < 0)
+	if (host_err < 0) {
+		commit_reset_write_verifier(nn, rqstp, host_err);
 		goto out_nfserr;
+	}
 
 	if (stable && fhp->fh_use_wgather) {
 		host_err = wait_for_concurrent_writes(file);
@@ -1694,6 +1696,8 @@ nfsd_commit(struct svc_rqst *rqstp, struct svc_fh *fhp, struct nfsd_file *nf,
 			nfsd_copy_write_verifier(verf, nn);
 			err2 = filemap_check_wb_err(nf->nf_file->f_mapping,
 						    since);
+			if (err2 < 0)
+				commit_reset_write_verifier(nn, rqstp, err2);
 			err = nfserrno(err2);
 			break;
 		case -EINVAL:

[PATCH 6.1.y 1/2] nfsd: Don't reset the write verifier on a commit EAGAIN

[Sasha Levin]

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

[ Upstream commit 1b2021bdeeca12364ad0fa7aac9ddba5cae964f3 ]

If fsync() is returning EAGAIN, then we can assume that the filesystem
being exported is something like NFS with the 'softerr' mount option
enabled, and that it is just asking us to replay the fsync() operation
at a later date.

If we see an ESTALE, then ditto: the file is gone, so there is no danger
of losing the error.

For those cases, do not reset the write verifier. A write verifier
change has a global effect, causing retransmission by all clients of
all uncommitted unstable writes for all files, so it is worth
mitigating where possible.

Link: https://lore.kernel.org/linux-nfs/20230911184357.11739-1-trond.myklebust@hammerspace.com/
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Stable-dep-of: 2090b05803fa ("nfsd: reset write verifier on deferred writeback errors")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/nfsd/vfs.c | 33 +++++++++++++++++++++++----------
 1 file changed, 23 insertions(+), 10 deletions(-)

diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
index 87a596fc6654dd..11eebaf49c24a4 100644
--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -334,6 +334,24 @@ nfsd_lookup(struct svc_rqst *rqstp, struct svc_fh *fhp, const char *name,
 	return err;
 }
 
+static void
+commit_reset_write_verifier(struct nfsd_net *nn, struct svc_rqst *rqstp,
+			    int err)
+{
+	switch (err) {
+	case -EAGAIN:
+	case -ESTALE:
+		/*
+		 * Neither of these are the result of a problem with
+		 * durable storage, so avoid a write verifier reset.
+		 */
+		break;
+	default:
+		nfsd_reset_write_verifier(nn);
+		trace_nfsd_writeverf_reset(nn, rqstp, err);
+	}
+}
+
 /*
  * Commit metadata changes to stable storage.
  */
@@ -646,8 +664,7 @@ __be32 nfsd4_clone_file_range(struct svc_rqst *rqstp,
 					&nfsd4_get_cstate(rqstp)->current_fh,
 					dst_pos,
 					count, status);
-			nfsd_reset_write_verifier(nn);
-			trace_nfsd_writeverf_reset(nn, rqstp, status);
+			commit_reset_write_verifier(nn, rqstp, status);
 			ret = nfserrno(status);
 		}
 	}
@@ -1126,8 +1143,7 @@ nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct nfsd_file *nf,
 	host_err = vfs_iter_write(file, &iter, &pos, flags);
 	file_end_write(file);
 	if (host_err < 0) {
-		nfsd_reset_write_verifier(nn);
-		trace_nfsd_writeverf_reset(nn, rqstp, host_err);
+		commit_reset_write_verifier(nn, rqstp, host_err);
 		goto out_nfserr;
 	}
 	*cnt = host_err;
@@ -1139,10 +1155,8 @@ nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct nfsd_file *nf,
 
 	if (stable && use_wgather) {
 		host_err = wait_for_concurrent_writes(file);
-		if (host_err < 0) {
-			nfsd_reset_write_verifier(nn);
-			trace_nfsd_writeverf_reset(nn, rqstp, host_err);
-		}
+		if (host_err < 0)
+			commit_reset_write_verifier(nn, rqstp, host_err);
 	}
 
 out_nfserr:
@@ -1277,8 +1291,7 @@ nfsd_commit(struct svc_rqst *rqstp, struct svc_fh *fhp, struct nfsd_file *nf,
 			err = nfserr_notsupp;
 			break;
 		default:
-			nfsd_reset_write_verifier(nn);
-			trace_nfsd_writeverf_reset(nn, rqstp, err2);
+			commit_reset_write_verifier(nn, rqstp, err2);
 			err = nfserrno(err2);
 		}
 	} else
-- 
2.53.0

[PATCH 6.1.y 2/2] nfsd: reset write verifier on deferred writeback errors

[Sasha Levin]

From: Jeff Layton <jlayton@kernel.org>

[ Upstream commit 2090b05803faab8a9fa62fbff871007862cac1b7 ]

nfsd_vfs_write() and nfsd_commit() both call filemap_check_wb_err() to
detect deferred writeback errors, but neither rotates the server's write
verifier (nn->writeverf) when this check fails. Every other
durable-storage-failure path in these functions calls
commit_reset_write_verifier() before returning an error.

The missing rotation means clients holding UNSTABLE write data under the
current verifier will COMMIT, receive the unchanged verifier back, and
conclude their data is durable — silently dropping data that failed
writeback. This violates the UNSTABLE+COMMIT durability contract
(RFC 1813 §3.3.7, RFC 8881 §18.32).

Add commit_reset_write_verifier() calls at both filemap_check_wb_err()
error sites, matching the pattern used by adjacent error paths in the
same functions. The helper already filters -EAGAIN and -ESTALE
internally, so the calls are unconditionally safe.

Reported-by: Chris Mason <clm@meta.com>
Fixes: 555dbf1a9aac ("nfsd: Replace use of rwsem with errseq_t")
Cc: stable@vger.kernel.org
Assisted-by: kres:claude-opus-4-6
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/nfsd/vfs.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
index 11eebaf49c24a4..ed5c9d075cca4f 100644
--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -1150,8 +1150,10 @@ nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct nfsd_file *nf,
 	nfsd_stats_io_write_add(nn, exp, *cnt);
 	fsnotify_modify(file);
 	host_err = filemap_check_wb_err(file->f_mapping, since);
-	if (host_err < 0)
+	if (host_err < 0) {
+		commit_reset_write_verifier(nn, rqstp, host_err);
 		goto out_nfserr;
+	}
 
 	if (stable && use_wgather) {
 		host_err = wait_for_concurrent_writes(file);
@@ -1285,6 +1287,8 @@ nfsd_commit(struct svc_rqst *rqstp, struct svc_fh *fhp, struct nfsd_file *nf,
 			nfsd_copy_write_verifier(verf, nn);
 			err2 = filemap_check_wb_err(nf->nf_file->f_mapping,
 						    since);
+			if (err2 < 0)
+				commit_reset_write_verifier(nn, rqstp, err2);
 			err = nfserrno(err2);
 			break;
 		case -EINVAL:
-- 
2.53.0

[PATCH 6.1.y 1/2] nfsd: release layout stid on setlease failure

[Chuck Lever]

From: Chris Mason <clm@meta.com>

commit 30d55c8aabb261bc3f427d6b9aae7ef6206063f9 upstream.

nfs4_alloc_stid() publishes the new stid into cl->cl_stateids via
idr_alloc_cyclic() under cl_lock before returning to
nfsd4_alloc_layout_stateid(). When nfsd4_layout_setlease() then
fails, the error path frees the layout stateid directly with
kmem_cache_free() without ever calling idr_remove(), leaving the
IDR slot pointing at freed slab memory. Any subsequent IDR walker
(states_show, client teardown) dereferences the dangling pointer.

The correct teardown for an IDR-published stid is nfs4_put_stid(),
which removes the IDR slot under cl_lock, dispatches sc_free
(nfsd4_free_layout_stateid) to release ls->ls_file via
nfsd4_close_layout(), and drops the nfs4_file reference in its
tail.

A second issue blocks that switch: nfsd4_free_layout_stateid()
unconditionally inspects ls->ls_fence_work via
delayed_work_pending() under ls_lock, but
INIT_DELAYED_WORK(&ls->ls_fence_work, ...) currently runs only
after the setlease call. On the setlease-failure path the
destructor would touch an uninitialized delayed_work.

    nfsd4_alloc_layout_stateid()
      nfs4_alloc_stid()           /* idr_alloc_cyclic under cl_lock */
      nfsd4_layout_setlease()     /* fails */
        nfs4_put_stid()
          nfsd4_free_layout_stateid()
            delayed_work_pending(&ls->ls_fence_work)  /* needs INIT */
            nfsd4_close_layout()  /* nfsd_file_put(ls->ls_file) */
          put_nfs4_file()

Fix by hoisting the ls_fenced / ls_fence_delay / INIT_DELAYED_WORK
initialization above the nfsd4_layout_setlease() call, and replace
the manual nfsd_file_put + put_nfs4_file + kmem_cache_free cleanup
with a single nfs4_put_stid(stp).

Fixes: c5c707f96fc9 ("nfsd: implement pNFS layout recalls")
Cc: stable@vger.kernel.org
Assisted-by: kres (claude-opus-4-7)
Signed-off-by: Chris Mason <clm@meta.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
[ cel: no ls_fence_work in 6.1.y; dropped INIT_DELAYED_WORK hunk ]
Signed-off-by: Chuck Lever <cel@kernel.org>
---
 fs/nfsd/nfs4layouts.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/fs/nfsd/nfs4layouts.c b/fs/nfsd/nfs4layouts.c
index 308214378fd3..84bb200e24ad 100644
--- a/fs/nfsd/nfs4layouts.c
+++ b/fs/nfsd/nfs4layouts.c
@@ -242,9 +242,7 @@ nfsd4_alloc_layout_stateid(struct nfsd4_compound_state *cstate,
 	BUG_ON(!ls->ls_file);
 
 	if (nfsd4_layout_setlease(ls)) {
-		nfsd_file_put(ls->ls_file);
-		put_nfs4_file(fp);
-		kmem_cache_free(nfs4_layout_stateid_cache, ls);
+		nfs4_put_stid(stp);
 		return NULL;
 	}
 
-- 
2.54.0

[PATCH 6.1.y 2/2] nfsd: reset write verifier on deferred writeback errors

[Chuck Lever]

From: Jeff Layton <jlayton@kernel.org>

commit 2090b05803faab8a9fa62fbff871007862cac1b7 upstream.

nfsd_vfs_write() and nfsd_commit() both call filemap_check_wb_err() to
detect deferred writeback errors, but neither rotates the server's write
verifier (nn->writeverf) when this check fails. Every other
durable-storage-failure path in these functions calls
commit_reset_write_verifier() before returning an error.

The missing rotation means clients holding UNSTABLE write data under the
current verifier will COMMIT, receive the unchanged verifier back, and
conclude their data is durable — silently dropping data that failed
writeback. This violates the UNSTABLE+COMMIT durability contract
(RFC 1813 §3.3.7, RFC 8881 §18.32).

Add commit_reset_write_verifier() calls at both filemap_check_wb_err()
error sites, matching the pattern used by adjacent error paths in the
same functions. The helper already filters -EAGAIN and -ESTALE
internally, so the calls are unconditionally safe.

Reported-by: Chris Mason <clm@meta.com>
Fixes: 555dbf1a9aac ("nfsd: Replace use of rwsem with errseq_t")
Cc: stable@vger.kernel.org
Assisted-by: kres:claude-opus-4-6
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
[ cel: open-code the reset; commit_reset_write_verifier() is v6.7 ]
Signed-off-by: Chuck Lever <cel@kernel.org>
---
 fs/nfsd/vfs.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
index 87a596fc6654..c40b2a706691 100644
--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -1134,8 +1134,11 @@ nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct nfsd_file *nf,
 	nfsd_stats_io_write_add(nn, exp, *cnt);
 	fsnotify_modify(file);
 	host_err = filemap_check_wb_err(file->f_mapping, since);
-	if (host_err < 0)
+	if (host_err < 0) {
+		nfsd_reset_write_verifier(nn);
+		trace_nfsd_writeverf_reset(nn, rqstp, host_err);
 		goto out_nfserr;
+	}
 
 	if (stable && use_wgather) {
 		host_err = wait_for_concurrent_writes(file);
@@ -1271,6 +1274,10 @@ nfsd_commit(struct svc_rqst *rqstp, struct svc_fh *fhp, struct nfsd_file *nf,
 			nfsd_copy_write_verifier(verf, nn);
 			err2 = filemap_check_wb_err(nf->nf_file->f_mapping,
 						    since);
+			if (err2 < 0) {
+				nfsd_reset_write_verifier(nn);
+				trace_nfsd_writeverf_reset(nn, rqstp, err2);
+			}
 			err = nfserrno(err2);
 			break;
 		case -EINVAL:
-- 
2.54.0