Patch "nfsd: Retry once in nfsd_open on an -EOPENSTALE return" has been added to the 5.10-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    nfsd: Retry once in nfsd_open on an -EOPENSTALE return

to the 5.10-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     nfsd-retry-once-in-nfsd_open-on-an-eopenstale-return.patch
and it can be found in the queue-5.10 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit b2e7882026e462c6a2fe7f2ab2e60fa25eebea01
Author: Jeff Layton <jeff.layton@xxxxxxxxxxxxxxx>
Date:   Sat Dec 18 20:37:56 2021 -0500

    nfsd: Retry once in nfsd_open on an -EOPENSTALE return
    
    [ Upstream commit 12bcbd40fd931472c7fc9cf3bfe66799ece93ed8 ]
    
    If we get back -EOPENSTALE from an NFSv4 open, then we either got some
    unhandled error or the inode we got back was not the same as the one
    associated with the dentry.
    
    We really have no recourse in that situation other than to retry the
    open, and if it fails to just return nfserr_stale back to the client.
    
    Signed-off-by: Jeff Layton <jeff.layton@xxxxxxxxxxxxxxx>
    Signed-off-by: Lance Shelton <lance.shelton@xxxxxxxxxxxxxxx>
    Signed-off-by: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
    Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/fs/nfsd/nfsproc.c b/fs/nfsd/nfsproc.c
index 6ed13754290a2..b8ddf21e70ea0 100644
--- a/fs/nfsd/nfsproc.c
+++ b/fs/nfsd/nfsproc.c
@@ -875,6 +875,7 @@ nfserrno (int errno)
 		{ nfserr_serverfault, -ESERVERFAULT },
 		{ nfserr_serverfault, -ENFILE },
 		{ nfserr_io, -EREMOTEIO },
+		{ nfserr_stale, -EOPENSTALE },
 		{ nfserr_io, -EUCLEAN },
 		{ nfserr_perm, -ENOKEY },
 		{ nfserr_no_grace, -ENOGRACE},
diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
index deaf4a50550d5..b343677b01efa 100644
--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -805,6 +805,7 @@ nfsd_open(struct svc_rqst *rqstp, struct svc_fh *fhp, umode_t type,
 		int may_flags, struct file **filp)
 {
 	__be32 err;
+	bool retried = false;
 
 	validate_process_creds();
 	/*
@@ -820,9 +821,16 @@ nfsd_open(struct svc_rqst *rqstp, struct svc_fh *fhp, umode_t type,
 	 */
 	if (type == S_IFREG)
 		may_flags |= NFSD_MAY_OWNER_OVERRIDE;
+retry:
 	err = fh_verify(rqstp, fhp, type, may_flags);
-	if (!err)
+	if (!err) {
 		err = __nfsd_open(rqstp, fhp, type, may_flags, filp);
+		if (err == nfserr_stale && !retried) {
+			retried = true;
+			fh_put(fhp);
+			goto retry;
+		}
+	}
 	validate_process_creds();
 	return err;
 }