fuse: make fuse_dentry_revalidate() RCU aware

Only bail out of fuse_dentry_revalidate() on LOOKUP_RCU when blocking
is actually necessary.

CC: Nick Piggin <npiggin@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>

diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c
index 3b84b91..c6ba49b 100644 (file)
--- a/fs/fuse/dir.c
+++ b/fs/fuse/dir.c
@@ -158,10 +158,7 @@ static int fuse_dentry_revalidate(struct dentry *entry, struct nameidata *nd)
 {
        struct inode *inode;
 
-       if (nd && nd->flags & LOOKUP_RCU)
-               return -ECHILD;
-
-       inode = entry->d_inode;
+       inode = ACCESS_ONCE(entry->d_inode);
        if (inode && is_bad_inode(inode))
                return 0;
        else if (fuse_dentry_time(entry) < get_jiffies_64()) {
@@ -177,6 +174,9 @@ static int fuse_dentry_revalidate(struct dentry *entry, struct nameidata *nd)
                if (!inode)
                        return 0;
 
+               if (nd->flags & LOOKUP_RCU)
+                       return -ECHILD;
+
                fc = get_fuse_conn(inode);
                req = fuse_get_req(fc);
                if (IS_ERR(req))