From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Yang Shi To: mgorman@techsingularity.net, tytso@mit.edu, adilger.kernel@dilger.ca, darrick.wong@oracle.com, dchinner@redhat.com, akpm@linux-foundation.org Cc: yang.shi@linux.alibaba.com, linux-ext4@vger.kernel.org, linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: [PATCH 2/2] fs: xfs: use BUG_ON if writepage call comes from direct reclaim Date: Tue, 3 Jul 2018 12:11:19 +0800 Message-Id: <1530591079-33813-2-git-send-email-yang.shi@linux.alibaba.com> In-Reply-To: <1530591079-33813-1-git-send-email-yang.shi@linux.alibaba.com> References: <1530591079-33813-1-git-send-email-yang.shi@linux.alibaba.com> Sender: owner-linux-mm@kvack.org List-ID: direct reclaim doesn't write out filesystem page, only kswapd could do this. So, if it is called from direct relaim, it is definitely a bug. And, Mel Gorman mentioned "Ultimately, this will be a BUG_ON." in commit 94054fa3fca1fd78db02cb3d68d5627120f0a1d4 ("xfs: warn if direct reclaim tries to writeback pages"), It has been many years since that commit, so it should be safe to elevate WARN_ON to BUG_ON now. Cc: Mel Gorman Cc: Darrick J. Wong Cc: Dave Chinner Signed-off-by: Yang Shi --- fs/xfs/xfs_aops.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c index 8eb3ba3..7efc2d2 100644 --- a/fs/xfs/xfs_aops.c +++ b/fs/xfs/xfs_aops.c @@ -1080,11 +1080,9 @@ static inline int xfs_bio_add_buffer(struct bio *bio, struct buffer_head *bh) * allow reclaim from kswapd as the stack usage there is relatively low. * * This should never happen except in the case of a VM regression so - * warn about it. + * BUG about it. */ - if (WARN_ON_ONCE((current->flags & (PF_MEMALLOC|PF_KSWAPD)) == - PF_MEMALLOC)) - goto redirty; + BUG_ON((current->flags & (PF_MEMALLOC|PF_KSWAPD)) == PF_MEMALLOC); /* * Given that we do not allow direct reclaim to call us, we should -- 1.8.3.1