From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx0b-00082601.pphosted.com ([67.231.153.30]:46266 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751556AbdCTEeP (ORCPT ); Mon, 20 Mar 2017 00:34:15 -0400 Subject: Re: [PATCH][PROGS] xfs_io: Allow setting multiple mode flags for fallocate() References: <20170318065554.GX17542@dastard> From: Calvin Owens Message-ID: <8dc5334b-a7b9-d455-25b5-5d651a3b918d@fb.com> Date: Sun, 19 Mar 2017 21:33:50 -0700 MIME-Version: 1.0 In-Reply-To: <20170318065554.GX17542@dastard> Content-Type: text/plain; charset="windows-1252"; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-xfs-owner@vger.kernel.org List-ID: List-Id: xfs To: Dave Chinner Cc: linux-xfs@vger.kernel.org, kernel-team@fb.com, calvinowens On 03/17/2017 11:55 PM, Dave Chinner wrote: > On Fri, Mar 17, 2017 at 06:26:09PM -0700, Calvin Owens wrote: >> This allows testing FALLOC_FL_PUNCH_HOLE|FALLOC_FL_KEEP_SIZE. > > Which is normally done through the "fpunch" command, which explains > why nobody has noticed this. Ah okay, I was assuming parity with syscalls in the commands and picked the first one I saw ;) >> Signed-off-by: Calvin Owens >> --- >> io/prealloc.c | 10 +++++----- >> 1 file changed, 5 insertions(+), 5 deletions(-) >> >> diff --git a/io/prealloc.c b/io/prealloc.c >> index a9d66cc..2a4bcdc 100644 >> --- a/io/prealloc.c >> +++ b/io/prealloc.c >> @@ -201,19 +201,19 @@ fallocate_f( >> while ((c = getopt(argc, argv, "cikpu")) != EOF) { >> switch (c) { >> case 'c': >> - mode = FALLOC_FL_COLLAPSE_RANGE; >> + mode |= FALLOC_FL_COLLAPSE_RANGE; >> break; >> case 'i': >> - mode = FALLOC_FL_INSERT_RANGE; >> + mode |= FALLOC_FL_INSERT_RANGE; >> break; >> case 'k': >> - mode = FALLOC_FL_KEEP_SIZE; >> + mode |= FALLOC_FL_KEEP_SIZE; >> break; >> case 'p': >> - mode = FALLOC_FL_PUNCH_HOLE; >> + mode |= FALLOC_FL_PUNCH_HOLE; >> break; >> case 'u': >> - mode = FALLOC_FL_UNSHARE_RANGE; >> + mode |= FALLOC_FL_UNSHARE_RANGE; >> break; > > NACK. We should not allow users to set invalid combinations > of commands such as 'falloc -cipu ...' - this would set the flags > (FALLOC_FL_COLLAPSE_RANGE | FALLOC_FL_INSERT_RANGE | > FALLOC_FL_PUNCH_HOLE | FALLOC_FL_UNSHARE_RANGE) and will always > error out. Isn't it potentially useful to test invalid behavior? > The use of FALLOC_FL_KEEP_SIZE for the FALLOC_FL_PUNCH_HOLE command > is essentially for documentation purposes - it does not do > truncation, hence the FALLOC_FL_KEEP_SIZE flag was added to it to > ensure developers understand that it does not truncate the file and > change EOF. > > IOWs, the fix needed to make the 'falloc -p' command work is really > just this: > > - mode = FALLOC_FL_PUNCH_HOLE; > + mode = FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE; My thinking was just "allow full exercising of the syscall", fpunch works for my testcase so if you'd prefer not to do that we can just drop this :) It might be worth cleaning up 'falloc' though: '-k' doesn't really make sense on its own right? Maybe remove "-k" and make "-p" OR in KEEP_SIZE like you suggest? Thanks, Calvin > Cheers, > > Dave. >