On 10/10/17 5:58 AM, Goldwyn Rodrigues wrote:
> From: Goldwyn Rodrigues <rgoldwyn@xxxxxxxx>
>
> This allows to make pwritev2() calls with RWF_NOWAIT,
> which would fail in case the call blocks.
>
> Signed-off-by: Goldwyn Rodrigues <rgoldwyn@xxxxxxxx>
>
> Changes since v2:
> - ifdef around -N which set RWF_NOWAIT
> ---
> io/pwrite.c | 10 +++++++++-
> man/man8/xfs_io.8 | 6 ++++++
> 2 files changed, 15 insertions(+), 1 deletion(-)
>
> diff --git a/io/pwrite.c b/io/pwrite.c
> index 5ceb26c7..e06dfb46 100644
> --- a/io/pwrite.c
> +++ b/io/pwrite.c
> @@ -53,6 +53,9 @@ pwrite_help(void)
> #ifdef HAVE_PWRITEV
> " -V N -- use vectored IO with N iovecs of blocksize each (pwritev)\n"
> #endif
> +#ifdef HAVE_PWRITEV2
> +" -N -- Perform the pwritev2() with RWF_NOWAIT\n"
> +#endif
> "\n"));
> }
This "-N" option didn't get added to the short help:
void
pwrite_init(void)
{
pwrite_cmd.name = "pwrite";
pwrite_cmd.altname = "w";
pwrite_cmd.cfunc = pwrite_f;
pwrite_cmd.argmin = 2;
pwrite_cmd.argmax = -1;
pwrite_cmd.flags = CMD_NOMAP_OK | CMD_FOREIGN_OK;
pwrite_cmd.args =
_("[-i infile [-d] [-s skip]] [-b bs] [-S seed] [-wW] [-FBR [-Z N]] [-V N] off len");
Is there any clean way to do that conditionally on the #ifdef as is done for long
help? Otherwise just more #ifdefs I guess.
> @@ -279,7 +282,7 @@ pwrite_f(
> init_cvtnum(&fsblocksize, &fssectsize);
> bsize = fsblocksize;
>
> - while ((c = getopt(argc, argv, "b:BCdf:Fi:qRs:S:uV:wWZ:")) != EOF) {
> + while ((c = getopt(argc, argv, "b:BCdf:Fi:NqRs:S:uV:wWZ:")) != EOF) {
> switch (c) {
> case 'b':
> tmp = cvtnum(fsblocksize, fssectsize, optarg);
> @@ -308,6 +311,11 @@ pwrite_f(
> case 'i':
> infile = optarg;
> break;
> +#ifdef HAVE_PWRITEV2
> + case 'N':
> + pwritev2_flags |= RWF_NOWAIT;
> + break;
> +#endif
If pwritev2 isn't present at build time, specifying -N gives somewhat unexpected behavior:
xfs_io> pwrite -N 0 1k
pwrite [-i infile [-d] [-s skip]] [-b bs] [-S seed] [-wW] [-FBR [-Z N]] [-V N] off len -- writes a number of bytes at a specified offset
xfs_io>
vs a wholly unknown option:
xfs_io> pwrite -K 0 1k
pwrite: invalid option -- 'K'
xfs_io>
because you have 'N' in the getopt string. I wonder if there's a better
way to handle it besides moar ifdefs ... I guess this wouldn't be
terrible:
+ case 'N':
+#ifdef HAVE_PWRITEV2
+ pwritev2_flags |= RWF_NOWAIT;
+#else
+ printf(_("Not built with pwritev2 functionality\n"));
+#endif
+ break;
> case 's':
> skip = cvtnum(fsblocksize, fssectsize, optarg);
> if (skip < 0) {
> diff --git a/man/man8/xfs_io.8 b/man/man8/xfs_io.8
> index 0fd9b951..9c58914f 100644
> --- a/man/man8/xfs_io.8
> +++ b/man/man8/xfs_io.8
> @@ -282,6 +282,12 @@ Use the vectored IO write syscall
> with a number of blocksize length iovecs. The number of iovecs is set by the
> .I vectors
> parameter.
> +.TP
> +.B \-N
> +Perform the
> +.BR pwritev2 (2)
> +call with
> +.I RWF_NOWAIT.
I guess maybe this should say something about "if it's built w/ pwritev2 functionality?"
I'm less worried about this, tbh, especially if -N gives the explanation above
if xfs_io doesn't have the support.
-Eric
> .RE
> .PD
> .TP
>
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