On Mon, Dec 09, 2019 at 04:00:17PM -0600, Eric Sandeen wrote:
> On 11/28/19 12:21 AM, Pavel Reichl wrote:
> > Some users are not happy about the BLKDISCARD taking too long and at the same
> > time not being informed about that - so they think that the command actually
> > hung.
> >
> > This commit changes code so that progress reporting is possible and also typing
> > the ^C will cancel the ongoing BLKDISCARD.
>
> Ok I'm going to nitpick this just a little bit more...
>
> > Signed-off-by: Pavel Reichl <preichl@xxxxxxxxxx>
> > ---
> > mkfs/xfs_mkfs.c | 50 ++++++++++++++++++++++++++++++++++++-------------
> > 1 file changed, 37 insertions(+), 13 deletions(-)
> >
> > diff --git a/mkfs/xfs_mkfs.c b/mkfs/xfs_mkfs.c
> > index 18338a61..0defadb2 100644
> > --- a/mkfs/xfs_mkfs.c
> > +++ b/mkfs/xfs_mkfs.c
> > @@ -1240,17 +1240,40 @@ done:
> > }
> >
> > static void
> > -discard_blocks(dev_t dev, uint64_t nsectors)
> > +discard_blocks(dev_t dev, uint64_t nsectors, int quiet)
> > {
> > - int fd;
> > + int fd;
> > + uint64_t offset = 0;
> > + /* Discard the device 2G at a time */
> > + const uint64_t step = 2ULL << 30;
> > + const uint64_t count = BBTOB(nsectors);
> >
> > - /*
> > - * We intentionally ignore errors from the discard ioctl. It is
> > - * not necessary for the mkfs functionality but just an optimization.
> > - */
> > fd = libxfs_device_to_fd(dev);
> > - if (fd > 0)
> > - platform_discard_blocks(fd, 0, nsectors << 9);
> > + if (fd <= 0)
> > + return;
> > + if (!quiet) {
> > + printf("Discarding blocks...\n");
> > + printf("...\n");
> > + }
>
> Let's change this output so that it prints only a single line, i.e.
>
> + if (!quiet) {
> + printf("Discarding blocks... ");
This needs fflush(stdout); here to force the message out of stdio output
buffering.
--D
>
> ...
>
> + if (!quiet)
> + printf("Done.\n");
>
> Then in xfstests there's only one line to filter.
>
> I think there was a suggestion to test isatty() to see if we're on a terminal,
> but I have some concern that a hung script will lead to confusion as well if
> there's no status message. We can add terminal testing in a later patch if that
> really seems like the right way to go.
>
> If you're ok with the above, I can make the change on commit to save another
> patch round trip, and
>
> Reviewed-by: Eric Sandeen <sandeen@xxxxxxxxxx>
>
> > +
> > + /* The block discarding happens in smaller batches so it can be
> > + * interrupted prematurely
> > + */
> > + while (offset < count) {
> > + uint64_t tmp_step = min(step, count - offset);
> > +
> > + /*
> > + * We intentionally ignore errors from the discard ioctl. It is
> > + * not necessary for the mkfs functionality but just an
> > + * optimization. However we should stop on error.
> > + */
> > + if (platform_discard_blocks(fd, offset, tmp_step))
> > + return;
> > +
> > + offset += tmp_step;
> > + }
> > + if (!quiet)
> > + printf("Done.\n");
> > }
> >
> > static __attribute__((noreturn)) void
> > @@ -2507,18 +2530,19 @@ open_devices(
> >
> > static void
> > discard_devices(
> > - struct libxfs_xinit *xi)
> > + struct libxfs_xinit *xi,
> > + int quiet)
> > {
> > /*
> > * This function has to be called after libxfs has been initialized.
> > */
> >
> > if (!xi->disfile)
> > - discard_blocks(xi->ddev, xi->dsize);
> > + discard_blocks(xi->ddev, xi->dsize, quiet);
> > if (xi->rtdev && !xi->risfile)
> > - discard_blocks(xi->rtdev, xi->rtsize);
> > + discard_blocks(xi->rtdev, xi->rtsize, quiet);
> > if (xi->logdev && xi->logdev != xi->ddev && !xi->lisfile)
> > - discard_blocks(xi->logdev, xi->logBBsize);
> > + discard_blocks(xi->logdev, xi->logBBsize, quiet);
> > }
> >
> > static void
> > @@ -3749,7 +3773,7 @@ main(
> > * All values have been validated, discard the old device layout.
> > */
> > if (discard && !dry_run)
> > - discard_devices(&xi);
> > + discard_devices(&xi, quiet);
> >
> > /*
> > * we need the libxfs buffer cache from here on in.
> >
