Patch "NFS: Avoid unnecessary rescanning of the per-server delegation list" has been added to the 5.15-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

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

    NFS: Avoid unnecessary rescanning of the per-server delegation list

to the 5.15-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:
     nfs-avoid-unnecessary-rescanning-of-the-per-server-d.patch
and it can be found in the queue-5.15 subdirectory.

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



commit 3d30d05f10cfb5dd8f79c9d5e1c380da9a6497fd
Author: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
Date:   Wed Aug 21 14:05:02 2024 -0400

    NFS: Avoid unnecessary rescanning of the per-server delegation list
    
    [ Upstream commit f92214e4c312f6ea9d78650cc6291d200f17abb6 ]
    
    If the call to nfs_delegation_grab_inode() fails, we will not have
    dropped any locks that require us to rescan the list.
    
    Signed-off-by: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
    Reviewed-by: Jeff Layton <jlayton@xxxxxxxxxx>
    Signed-off-by: Anna Schumaker <Anna.Schumaker@xxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/fs/nfs/delegation.c b/fs/nfs/delegation.c
index 6a3ba306c321..8124d4f8b29a 100644
--- a/fs/nfs/delegation.c
+++ b/fs/nfs/delegation.c
@@ -627,6 +627,9 @@ static int nfs_server_return_marked_delegations(struct nfs_server *server,
 				prev = delegation;
 			continue;
 		}
+		inode = nfs_delegation_grab_inode(delegation);
+		if (inode == NULL)
+			continue;
 
 		if (prev) {
 			struct inode *tmp = nfs_delegation_grab_inode(prev);
@@ -637,12 +640,6 @@ static int nfs_server_return_marked_delegations(struct nfs_server *server,
 			}
 		}
 
-		inode = nfs_delegation_grab_inode(delegation);
-		if (inode == NULL) {
-			rcu_read_unlock();
-			iput(to_put);
-			goto restart;
-		}
 		delegation = nfs_start_delegation_return_locked(NFS_I(inode));
 		rcu_read_unlock();
 
@@ -1164,7 +1161,6 @@ static int nfs_server_reap_unclaimed_delegations(struct nfs_server *server,
 	struct inode *inode;
 restart:
 	rcu_read_lock();
-restart_locked:
 	list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
 		if (test_bit(NFS_DELEGATION_INODE_FREEING,
 					&delegation->flags) ||
@@ -1175,7 +1171,7 @@ static int nfs_server_reap_unclaimed_delegations(struct nfs_server *server,
 			continue;
 		inode = nfs_delegation_grab_inode(delegation);
 		if (inode == NULL)
-			goto restart_locked;
+			continue;
 		delegation = nfs_start_delegation_return_locked(NFS_I(inode));
 		rcu_read_unlock();
 		if (delegation != NULL) {
@@ -1296,7 +1292,6 @@ static int nfs_server_reap_expired_delegations(struct nfs_server *server,
 	nfs4_stateid stateid;
 restart:
 	rcu_read_lock();
-restart_locked:
 	list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
 		if (test_bit(NFS_DELEGATION_INODE_FREEING,
 					&delegation->flags) ||
@@ -1307,7 +1302,7 @@ static int nfs_server_reap_expired_delegations(struct nfs_server *server,
 			continue;
 		inode = nfs_delegation_grab_inode(delegation);
 		if (inode == NULL)
-			goto restart_locked;
+			continue;
 		spin_lock(&delegation->lock);
 		cred = get_cred_rcu(delegation->cred);
 		nfs4_stateid_copy(&stateid, &delegation->stateid);