GFS2: Post-VFS scale update for RCU path walk

We can allow a few more cases to use RCU path walking than
originally allowed. It should be possible to also enable
RCU path walking when the glock is already cached. Thats
a bit more complicated though, so left for a future patch.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Cc: Nick Piggin <npiggin@gmail.com>

1 files changed, 5 insertions, 2 deletions

diff --git a/fs/gfs2/acl.c b/fs/gfs2/acl.c
index 7118f1a780a9..cbc07155b1a0 100644
--- a/fs/gfs2/acl.c
+++ b/fs/gfs2/acl.c
@@ -80,8 +80,11 @@ int gfs2_check_acl(struct inode *inode, int mask, unsigned int flags)
         struct posix_acl *acl;
         int error;
 
-        if (flags & IPERM_FLAG_RCU)
-                return -ECHILD;
+        if (flags & IPERM_FLAG_RCU) {
+                if (!negative_cached_acl(inode, ACL_TYPE_ACCESS))
+                        return -ECHILD;
+                return -EAGAIN;
+        }
 
         acl = gfs2_acl_get(GFS2_I(inode), ACL_TYPE_ACCESS);
         if (IS_ERR(acl))