fuse: don't WARN when nlink is zero

drop_nlink() warns if nlink is already zero.  This is triggerable by a buggy
userspace filesystem.  The cure, I think, is worse than the disease so disable
the warning.

Reported-by: Tero Roponen <tero.roponen@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>

diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c
index dc5e64893375ffcf2caa1dba652d0ac0fb66863c..2b112d978e9f53676e1ab684dc9ab5d9fed9f269 100644 (file)
--- a/fs/fuse/dir.c
+++ b/fs/fuse/dir.c
@@ -705,7 +705,14 @@ static int fuse_unlink(struct inode *dir, struct dentry *entry)
 
                spin_lock(&fc->lock);
                fi->attr_version = ++fc->attr_version;
-               drop_nlink(inode);
+               /*
+                * If i_nlink == 0 then unlink doesn't make sense, yet this can
+                * happen if userspace filesystem is careless.  It would be
+                * difficult to enforce correct nlink usage so just ignore this
+                * condition here
+                */
+               if (inode->i_nlink > 0)
+                       drop_nlink(inode);
                spin_unlock(&fc->lock);
                fuse_invalidate_attr(inode);
                fuse_invalidate_attr(dir);