NFS: Fix wakeup of __nfs_lookup_revalidate() in unblock_revalidate()

JIRA: https://issues.redhat.com/browse/RHEL-117497

commit 1db3a48
Author: Trond Myklebust <trond.myklebust@hammerspace.com>
Date:   Fri Jul 18 16:15:27 2025 -0700

    NFS: Fix wakeup of __nfs_lookup_revalidate() in unblock_revalidate()

    Use store_release_wake_up() to add the appropriate memory barrier before
    calling wake_up_var(&dentry->d_fsdata).

    Reported-by: Lukáš Hejtmánek<xhejtman@ics.muni.cz>
    Suggested-by: Santosh Pradhan <santosh.pradhan@gmail.com>
    Link: https://lore.kernel.org/all/18945D18-3EDB-4771-B019-0335CE671077@ics.muni.cz/
    Fixes: 99bc9f2 ("NFS: add barriers when testing for NFS_FSDATA_BLOCKED")
    Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Signed-off-by: Benjamin Coddington <bcodding@redhat.com>

Author: bcodding-rh

fs/nfs/dir.c

@@ -1840,9 +1840,7 @@ static void block_revalidate(struct dentry *dentry)
 
 static void unblock_revalidate(struct dentry *dentry)
 {
-	/* store_release ensures wait_var_event() sees the update */
-	smp_store_release(&dentry->d_fsdata, NULL);
-	wake_up_var(&dentry->d_fsdata);
+	store_release_wake_up(&dentry->d_fsdata, NULL);
 }
 
 /*