Patch "NFSD: fix leaked reference count of nfsd4_ssc_umount_item" 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

    NFSD: fix leaked reference count of nfsd4_ssc_umount_item

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:
     nfsd-fix-leaked-reference-count-of-nfsd4_ssc_umount_.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 15d5aad60bb8e804d6d6aaccdb94ae6c5904f8f7
Author: Dai Ngo <dai.ngo@xxxxxxxxxx>
Date:   Mon Jan 23 21:34:13 2023 -0800

    NFSD: fix leaked reference count of nfsd4_ssc_umount_item
    
    [ Upstream commit 34e8f9ec4c9ac235f917747b23a200a5e0ec857b ]
    
    The reference count of nfsd4_ssc_umount_item is not decremented
    on error conditions. This prevents the laundromat from unmounting
    the vfsmount of the source file.
    
    This patch decrements the reference count of nfsd4_ssc_umount_item
    on error.
    
    Fixes: f4e44b393389 ("NFSD: delay unmount source's export after inter-server copy completed.")
    Signed-off-by: Dai Ngo <dai.ngo@xxxxxxxxxx>
    Reviewed-by: Jeff Layton <jlayton@xxxxxxxxxx>
    Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>

diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
index ada46ef5a093d..c95e7ec5fb530 100644
--- a/fs/nfsd/nfs4proc.c
+++ b/fs/nfsd/nfs4proc.c
@@ -1813,13 +1813,17 @@ nfsd4_copy(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
 	release_copy_files(copy);
 	return status;
 out_err:
+	if (nfsd4_ssc_is_inter(copy)) {
+		/*
+		 * Source's vfsmount of inter-copy will be unmounted
+		 * by the laundromat. Use copy instead of async_copy
+		 * since async_copy->ss_nsui might not be set yet.
+		 */
+		refcount_dec(&copy->ss_nsui->nsui_refcnt);
+	}
 	if (async_copy)
 		cleanup_async_copy(async_copy);
 	status = nfserrno(-ENOMEM);
-	/*
-	 * source's vfsmount of inter-copy will be unmounted
-	 * by the laundromat
-	 */
 	goto out;
 }