fs/9p: fix error reporting in v9fs_dir_release

Checking the p9_fid_put value allows us to pass back errors
involved if we end up clunking the fid as part of dir_release.

This can help with more graceful response to errors in writeback
among other things.
Signed-off-by: Eric Van Hensbergen <ericvh@kernel.org>
Reviewed-by: Dominique Martinet <asmadeus@codewreck.org>

fs/9p/vfs_dir.c

@@ -197,7 +197,7 @@ static int v9fs_dir_readdir_dotl(struct file *file, struct dir_context *ctx)
 
 
 /**
- * v9fs_dir_release - close a directory
+ * v9fs_dir_release - called on a close of a file or directory
  * @inode: inode of the directory
  * @filp: file pointer to a directory
  *
@@ -209,6 +209,7 @@ int v9fs_dir_release(struct inode *inode, struct file *filp)
 	struct p9_fid *fid;
 	__le32 version;
 	loff_t i_size;
+	int retval = 0;
 
 	fid = filp->private_data;
 	p9_debug(P9_DEBUG_VFS, "inode: %p filp: %p fid: %d\n",
@@ -217,7 +218,7 @@ int v9fs_dir_release(struct inode *inode, struct file *filp)
 		spin_lock(&inode->i_lock);
 		hlist_del(&fid->ilist);
 		spin_unlock(&inode->i_lock);
-		p9_fid_put(fid);
+		retval = p9_fid_put(fid);
 	}
 
 	if ((filp->f_mode & FMODE_WRITE)) {
@@ -228,7 +229,7 @@ int v9fs_dir_release(struct inode *inode, struct file *filp)
 	} else {
 		fscache_unuse_cookie(v9fs_inode_cookie(v9inode), NULL, NULL);
 	}
-	return 0;
+	return retval;
 }
 
 const struct file_operations v9fs_dir_operations = {