From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qt0-f196.google.com ([209.85.216.196]:37166 "EHLO mail-qt0-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728184AbeIKW6z (ORCPT ); Tue, 11 Sep 2018 18:58:55 -0400 Received: by mail-qt0-f196.google.com with SMTP id n6-v6so29178164qtl.4 for ; Tue, 11 Sep 2018 10:58:29 -0700 (PDT) From: Josef Bacik To: kernel-team@fb.com, linux-btrfs@vger.kernel.org Subject: [PATCH 10/36] btrfs: protect space cache inode alloc with nofs Date: Tue, 11 Sep 2018 13:57:41 -0400 Message-Id: <20180911175807.26181-11-josef@toxicpanda.com> In-Reply-To: <20180911175807.26181-1-josef@toxicpanda.com> References: <20180911175807.26181-1-josef@toxicpanda.com> Sender: linux-btrfs-owner@vger.kernel.org List-ID: If we're allocating a new space cache inode it's likely going to be under a transaction handle, so we need to use memalloc_nofs_save() in order to avoid deadlocks, and more importantly lockdep messages that make xfstests fail. Reviewed-by: Omar Sandoval Signed-off-by: Josef Bacik --- fs/btrfs/free-space-cache.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c index c3888c113d81..e077ad3b4549 100644 --- a/fs/btrfs/free-space-cache.c +++ b/fs/btrfs/free-space-cache.c @@ -10,6 +10,7 @@ #include #include #include +#include #include "ctree.h" #include "free-space-cache.h" #include "transaction.h" @@ -47,6 +48,7 @@ static struct inode *__lookup_free_space_inode(struct btrfs_root *root, struct btrfs_free_space_header *header; struct extent_buffer *leaf; struct inode *inode = NULL; + unsigned nofs_flag; int ret; key.objectid = BTRFS_FREE_SPACE_OBJECTID; @@ -68,7 +70,13 @@ static struct inode *__lookup_free_space_inode(struct btrfs_root *root, btrfs_disk_key_to_cpu(&location, &disk_key); btrfs_release_path(path); + /* + * We are often under a trans handle at this point, so we need to make + * sure NOFS is set to keep us from deadlocking. + */ + nofs_flag = memalloc_nofs_save(); inode = btrfs_iget(fs_info->sb, &location, root, NULL); + memalloc_nofs_restore(nofs_flag); if (IS_ERR(inode)) return inode; -- 2.14.3