Patch "NFSD: Refactor nfsd_setattr()" 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: Refactor nfsd_setattr()

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-refactor-nfsd_setattr.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 56ef4b9ae70f84e4dced1f5b74db75587bdc86a8
Author: Chuck Lever <chuck.lever@xxxxxxxxxx>
Date:   Thu Sep 8 18:14:07 2022 -0400

    NFSD: Refactor nfsd_setattr()
    
    [ Upstream commit c0aa1913db57219e91a0a8832363cbafb3a9cf8f ]
    
    Move code that will be retried (in a subsequent patch) into a helper
    function.
    
    Reviewed-by: Jeff Layton <jlayton@xxxxxxxxxx>
    [ cel: backported to 5.10.y, prior to idmapped mounts ]
    Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
index 5ec1119a87859..e32b0c807ea9d 100644
--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -356,8 +356,61 @@ nfsd_get_write_access(struct svc_rqst *rqstp, struct svc_fh *fhp,
 	return nfserrno(host_err);
 }
 
-/*
- * Set various file attributes.  After this call fhp needs an fh_put.
+static int __nfsd_setattr(struct dentry *dentry, struct iattr *iap)
+{
+	int host_err;
+
+	if (iap->ia_valid & ATTR_SIZE) {
+		/*
+		 * RFC5661, Section 18.30.4:
+		 *   Changing the size of a file with SETATTR indirectly
+		 *   changes the time_modify and change attributes.
+		 *
+		 * (and similar for the older RFCs)
+		 */
+		struct iattr size_attr = {
+			.ia_valid	= ATTR_SIZE | ATTR_CTIME | ATTR_MTIME,
+			.ia_size	= iap->ia_size,
+		};
+
+		if (iap->ia_size < 0)
+			return -EFBIG;
+
+		host_err = notify_change(dentry, &size_attr, NULL);
+		if (host_err)
+			return host_err;
+		iap->ia_valid &= ~ATTR_SIZE;
+
+		/*
+		 * Avoid the additional setattr call below if the only other
+		 * attribute that the client sends is the mtime, as we update
+		 * it as part of the size change above.
+		 */
+		if ((iap->ia_valid & ~ATTR_MTIME) == 0)
+			return 0;
+	}
+
+	if (!iap->ia_valid)
+		return 0;
+
+	iap->ia_valid |= ATTR_CTIME;
+	return notify_change(dentry, iap, NULL);
+}
+
+/**
+ * nfsd_setattr - Set various file attributes.
+ * @rqstp: controlling RPC transaction
+ * @fhp: filehandle of target
+ * @attr: attributes to set
+ * @check_guard: set to 1 if guardtime is a valid timestamp
+ * @guardtime: do not act if ctime.tv_sec does not match this timestamp
+ *
+ * This call may adjust the contents of @attr (in particular, this
+ * call may change the bits in the na_iattr.ia_valid field).
+ *
+ * Returns nfs_ok on success, otherwise an NFS status code is
+ * returned. Caller must release @fhp by calling fh_put in either
+ * case.
  */
 __be32
 nfsd_setattr(struct svc_rqst *rqstp, struct svc_fh *fhp,
@@ -370,7 +423,7 @@ nfsd_setattr(struct svc_rqst *rqstp, struct svc_fh *fhp,
 	int		accmode = NFSD_MAY_SATTR;
 	umode_t		ftype = 0;
 	__be32		err;
-	int		host_err = 0;
+	int		host_err;
 	bool		get_write_count;
 	bool		size_change = (iap->ia_valid & ATTR_SIZE);
 
@@ -427,43 +480,7 @@ nfsd_setattr(struct svc_rqst *rqstp, struct svc_fh *fhp,
 	}
 
 	inode_lock(inode);
-	if (size_change) {
-		/*
-		 * RFC5661, Section 18.30.4:
-		 *   Changing the size of a file with SETATTR indirectly
-		 *   changes the time_modify and change attributes.
-		 *
-		 * (and similar for the older RFCs)
-		 */
-		struct iattr size_attr = {
-			.ia_valid	= ATTR_SIZE | ATTR_CTIME | ATTR_MTIME,
-			.ia_size	= iap->ia_size,
-		};
-
-		host_err = -EFBIG;
-		if (iap->ia_size < 0)
-			goto out_unlock;
-
-		host_err = notify_change(dentry, &size_attr, NULL);
-		if (host_err)
-			goto out_unlock;
-		iap->ia_valid &= ~ATTR_SIZE;
-
-		/*
-		 * Avoid the additional setattr call below if the only other
-		 * attribute that the client sends is the mtime, as we update
-		 * it as part of the size change above.
-		 */
-		if ((iap->ia_valid & ~ATTR_MTIME) == 0)
-			goto out_unlock;
-	}
-
-	if (iap->ia_valid) {
-		iap->ia_valid |= ATTR_CTIME;
-		host_err = notify_change(dentry, iap, NULL);
-	}
-
-out_unlock:
+	host_err = __nfsd_setattr(dentry, iap);
 	if (attr->na_seclabel && attr->na_seclabel->len)
 		attr->na_labelerr = security_inode_setsecctx(dentry,
 			attr->na_seclabel->data, attr->na_seclabel->len);