From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg1-f193.google.com ([209.85.215.193]:43644 "EHLO mail-pg1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726944AbeHIUb7 (ORCPT ); Thu, 9 Aug 2018 16:31:59 -0400 From: Naohiro Aota To: David Sterba , linux-btrfs@vger.kernel.org Cc: Chris Mason , Josef Bacik , linux-kernel@vger.kernel.org, Hannes Reinecke , Damien Le Moal , Bart Van Assche , Matias Bjorling , Naohiro Aota Subject: [RFC PATCH 05/17] btrfs: disable fallocate in HMZONED mode Date: Fri, 10 Aug 2018 03:04:38 +0900 Message-Id: <20180809180450.5091-6-naota@elisp.net> In-Reply-To: <20180809180450.5091-1-naota@elisp.net> References: <20180809180450.5091-1-naota@elisp.net> Sender: linux-btrfs-owner@vger.kernel.org List-ID: fallocate() is implemented by reserving actual extent instead of reservations. This can result in exposing the sequential write constraint of host-managed zoned block devices to the application, which would break the POSIX semantic for the fallocated file. To avoid this, report fallocate() as not supported when in HMZONED mode. Signed-off-by: Naohiro Aota --- fs/btrfs/file.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c index 095f0bb86bb7..6f4546ccb57d 100644 --- a/fs/btrfs/file.c +++ b/fs/btrfs/file.c @@ -2993,6 +2993,10 @@ static long btrfs_fallocate(struct file *file, int mode, alloc_end = round_up(offset + len, blocksize); cur_offset = alloc_start; + /* Do not allow fallocate in HMZONED mode */ + if (btrfs_fs_incompat(btrfs_sb(inode->i_sb), HMZONED)) + return -EOPNOTSUPP; + /* Make sure we aren't being give some crap mode */ if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE | FALLOC_FL_ZERO_RANGE)) -- 2.18.0