Re: [PATCH v1] xfs_io: add RWF_ATOMIC support to pwrite

[John Garry <john.g.garry@oracle.com>]

On 02/10/2024 02:01, Darrick J. Wong wrote:
> On Tue, Oct 01, 2024 at 11:28:49AM -0700, Catherine Hoang wrote:
>> Enable testing write behavior with the per-io RWF_ATOMIC flag.
>>
>> Signed-off-by: Catherine Hoang <catherine.hoang@oracle.com>
> 
> Looks ok, though are there testcases for us to look at as well?

Since we are now decoupling forcealign from atomic writes, those test 
cases will require some rewriting.

> Reviewed-by: Darrick J. Wong <djwong@kernel.org>

Reviewed-by: John Garry <john.g.garry@oracle.com>

> 
> --D
> 
>> ---
>>   include/linux.h   | 5 +++++
>>   io/pwrite.c       | 8 ++++++--
>>   man/man8/xfs_io.8 | 8 +++++++-
>>   3 files changed, 18 insertions(+), 3 deletions(-)
>>
>> diff --git a/include/linux.h b/include/linux.h
>> index a13072d2..e9eb7bfb 100644
>> --- a/include/linux.h
>> +++ b/include/linux.h
>> @@ -231,6 +231,11 @@ struct fsxattr {
>>   #define FS_XFLAG_COWEXTSIZE	0x00010000	/* CoW extent size allocator hint */
>>   #endif
>>   
>> +/* Atomic Write */
>> +#ifndef RWF_ATOMIC
>> +#define RWF_ATOMIC	((__kernel_rwf_t)0x00000040)
>> +#endif
>> +
>>   /*
>>    * Reminder: anything added to this file will be compiled into downstream
>>    * userspace projects!
>> diff --git a/io/pwrite.c b/io/pwrite.c
>> index a88cecc7..fab59be4 100644
>> --- a/io/pwrite.c
>> +++ b/io/pwrite.c
>> @@ -44,6 +44,7 @@ pwrite_help(void)
>>   #ifdef HAVE_PWRITEV2
>>   " -N   -- Perform the pwritev2() with RWF_NOWAIT\n"
>>   " -D   -- Perform the pwritev2() with RWF_DSYNC\n"
>> +" -A   -- Perform the pwritev2() with RWF_ATOMIC\n"
>>   #endif
>>   "\n"));
>>   }
>> @@ -284,7 +285,7 @@ pwrite_f(
>>   	init_cvtnum(&fsblocksize, &fssectsize);
>>   	bsize = fsblocksize;
>>   
>> -	while ((c = getopt(argc, argv, "b:BCdDf:Fi:NqRs:OS:uV:wWZ:")) != EOF) {
>> +	while ((c = getopt(argc, argv, "Ab:BCdDf:Fi:NqRs:OS:uV:wWZ:")) != EOF) {
>>   		switch (c) {
>>   		case 'b':
>>   			tmp = cvtnum(fsblocksize, fssectsize, optarg);
>> @@ -324,6 +325,9 @@ pwrite_f(
>>   		case 'D':
>>   			pwritev2_flags |= RWF_DSYNC;
>>   			break;
>> +		case 'A':
>> +			pwritev2_flags |= RWF_ATOMIC;
>> +			break;
>>   #endif
>>   		case 's':
>>   			skip = cvtnum(fsblocksize, fssectsize, optarg);
>> @@ -476,7 +480,7 @@ pwrite_init(void)
>>   	pwrite_cmd.argmax = -1;
>>   	pwrite_cmd.flags = CMD_NOMAP_OK | CMD_FOREIGN_OK;
>>   	pwrite_cmd.args =
>> -_("[-i infile [-qdDwNOW] [-s skip]] [-b bs] [-S seed] [-FBR [-Z N]] [-V N] off len");
>> +_("[-i infile [-qAdDwNOW] [-s skip]] [-b bs] [-S seed] [-FBR [-Z N]] [-V N] off len");
>>   	pwrite_cmd.oneline =
>>   		_("writes a number of bytes at a specified offset");
>>   	pwrite_cmd.help = pwrite_help;
>> diff --git a/man/man8/xfs_io.8 b/man/man8/xfs_io.8
>> index 303c6447..1e790139 100644
>> --- a/man/man8/xfs_io.8
>> +++ b/man/man8/xfs_io.8
>> @@ -244,7 +244,7 @@ See the
>>   .B pread
>>   command.
>>   .TP
>> -.BI "pwrite [ \-i " file " ] [ \-qdDwNOW ] [ \-s " skip " ] [ \-b " size " ] [ \-S " seed " ] [ \-FBR [ \-Z " zeed " ] ] [ \-V " vectors " ] " "offset length"
>> +.BI "pwrite [ \-i " file " ] [ \-qAdDwNOW ] [ \-s " skip " ] [ \-b " size " ] [ \-S " seed " ] [ \-FBR [ \-Z " zeed " ] ] [ \-V " vectors " ] " "offset length"
>>   Writes a range of bytes in a specified blocksize from the given
>>   .IR offset .
>>   The bytes written can be either a set pattern or read in from another
>> @@ -281,6 +281,12 @@ Perform the
>>   call with
>>   .IR RWF_DSYNC .
>>   .TP
>> +.B \-A
>> +Perform the
>> +.BR pwritev2 (2)
>> +call with
>> +.IR RWF_ATOMIC .
>> +.TP
>>   .B \-O
>>   perform pwrite once and return the (maybe partial) bytes written.
>>   .TP
>> -- 
>> 2.34.1
>>
>>