From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-yw1-f66.google.com ([209.85.161.66]:43567 "EHLO mail-yw1-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725846AbeIAEYw (ORCPT ); Sat, 1 Sep 2018 00:24:52 -0400 Received: by mail-yw1-f66.google.com with SMTP id l189-v6so5641234ywb.10 for ; Fri, 31 Aug 2018 17:14:57 -0700 (PDT) Date: Fri, 31 Aug 2018 17:14:52 -0700 From: Omar Sandoval To: Josef Bacik Cc: linux-btrfs@vger.kernel.org Subject: Re: [PATCH 09/35] btrfs: protect space cache inode alloc with nofs Message-ID: <20180901001452.GC29370@vader> References: <20180830174225.2200-1-josef@toxicpanda.com> <20180830174225.2200-10-josef@toxicpanda.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <20180830174225.2200-10-josef@toxicpanda.com> Sender: linux-btrfs-owner@vger.kernel.org List-ID: On Thu, Aug 30, 2018 at 01:41:59PM -0400, Josef Bacik wrote: > 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. Could use a comment where we call memalloc_nofs_save(). Otherwise, Reviewed-by: Omar Sandoval > Signed-off-by: Josef Bacik > --- > fs/btrfs/free-space-cache.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c > index c3888c113d81..db93a5f035a0 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 +70,9 @@ static struct inode *__lookup_free_space_inode(struct btrfs_root *root, > btrfs_disk_key_to_cpu(&location, &disk_key); > btrfs_release_path(path); > > + 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 >