5.10-stable patches

added patches:
	nfsd-fix-verifier-returned-in-stable-writes.patch

diff --git a/queue-5.10/nfsd-fix-verifier-returned-in-stable-writes.patch b/queue-5.10/nfsd-fix-verifier-returned-in-stable-writes.patch
new file mode 100644 (file)
index 0000000..1d08037
--- /dev/null
+++ b/queue-5.10/nfsd-fix-verifier-returned-in-stable-writes.patch
@@ -0,0 +1,73 @@
+From f11ad7aa653130b71e2e89bed207f387718216d5 Mon Sep 17 00:00:00 2001
+From: Chuck Lever <chuck.lever@oracle.com>
+Date: Tue, 28 Dec 2021 12:35:43 -0500
+Subject: NFSD: Fix verifier returned in stable WRITEs
+
+From: Chuck Lever <chuck.lever@oracle.com>
+
+commit f11ad7aa653130b71e2e89bed207f387718216d5 upstream.
+
+RFC 8881 explains the purpose of the write verifier this way:
+
+> The final portion of the result is the field writeverf. This field
+> is the write verifier and is a cookie that the client can use to
+> determine whether a server has changed instance state (e.g., server
+> restart) between a call to WRITE and a subsequent call to either
+> WRITE or COMMIT.
+
+But then it says:
+
+> This cookie MUST be unchanged during a single instance of the
+> NFSv4.1 server and MUST be unique between instances of the NFSv4.1
+> server. If the cookie changes, then the client MUST assume that
+> any data written with an UNSTABLE4 value for committed and an old
+> writeverf in the reply has been lost and will need to be
+> recovered.
+
+RFC 1813 has similar language for NFSv3. NFSv2 does not have a write
+verifier since it doesn't implement the COMMIT procedure.
+
+Since commit 19e0663ff9bc ("nfsd: Ensure sampling of the write
+verifier is atomic with the write"), the Linux NFS server has
+returned a boot-time-based verifier for UNSTABLE WRITEs, but a zero
+verifier for FILE_SYNC and DATA_SYNC WRITEs. FILE_SYNC and DATA_SYNC
+WRITEs are not followed up with a COMMIT, so there's no need for
+clients to compare verifiers for stable writes.
+
+However, by returning a different verifier for stable and unstable
+writes, the above commit puts the Linux NFS server a step farther
+out of compliance with the first MUST above. At least one NFS client
+(FreeBSD) noticed the difference, making this a potential
+regression.
+
+[Removed down_write to fix the conflict in the cherry-pick. The
+down_write functionality was no longer needed there. Upstream commit
+555dbf1a9aac6d3150c8b52fa35f768a692f4eeb titled nfsd: Replace use of
+rwsem with errseq_t removed those and replace it with new functionality
+that was more scalable. This commit is already backported onto 5.10 and
+so removing down_write ensures consistency with that change. Tested by
+compiling and booting successfully. - kochera]
+
+Reported-by: Rick Macklem <rmacklem@uoguelph.ca>
+Link: https://lore.kernel.org/linux-nfs/YQXPR0101MB096857EEACF04A6DF1FC6D9BDD749@YQXPR0101MB0968.CANPRD01.PROD.OUTLOOK.COM/T/
+Fixes: 19e0663ff9bc ("nfsd: Ensure sampling of the write verifier is atomic with the write")
+Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
+Signed-off-by: Michael Kochera <kochera@google.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ fs/nfsd/vfs.c |    4 ++++
+ 1 file changed, 4 insertions(+)
+
+--- a/fs/nfsd/vfs.c
++++ b/fs/nfsd/vfs.c
+@@ -1014,6 +1014,10 @@ nfsd_vfs_write(struct svc_rqst *rqstp, s
+       iov_iter_kvec(&iter, WRITE, vec, vlen, *cnt);
+       since = READ_ONCE(file->f_wb_err);
+       if (flags & RWF_SYNC) {
++              if (verf)
++                      nfsd_copy_boot_verifier(verf,
++                                      net_generic(SVC_NET(rqstp),
++                                      nfsd_net_id));
+               host_err = vfs_iter_write(file, &iter, &pos, flags);
+               if (host_err < 0)
+                       nfsd_reset_boot_verifier(net_generic(SVC_NET(rqstp),

diff --git a/queue-5.10/series b/queue-5.10/series
new file mode 100644 (file)
index 0000000..65009bd
--- /dev/null
+++ b/queue-5.10/series
@@ -0,0 +1 @@
+nfsd-fix-verifier-returned-in-stable-writes.patch