Re: [PATCH] block/file-posix: Fix return value translation for AIO discards.

[Stefan Hajnoczi <stefanha@redhat.com>]

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On Tue, Oct 19, 2021 at 05:40:13AM +0200, Philippe Mathieu-Daudé wrote:
> +Stefan
> 
> On 10/18/21 20:07, Ari Sundholm wrote:
> > AIO discards regressed as a result of the following commit:
> > 	0dfc7af2 block/file-posix: Optimize for macOS
> > 
> > When trying to run blkdiscard within a Linux guest, the request would
> > fail, with some errors in dmesg:
> > 
> > ---- [ snip ] ----
> > [    4.010070] sd 2:0:0:0: [sda] tag#0 FAILED Result: hostbyte=DID_OK
> > driverbyte=DRIVER_SENSE
> > [    4.011061] sd 2:0:0:0: [sda] tag#0 Sense Key : Aborted Command
> > [current]
> > [    4.011061] sd 2:0:0:0: [sda] tag#0 Add. Sense: I/O process
> > terminated
> > [    4.011061] sd 2:0:0:0: [sda] tag#0 CDB: Unmap/Read sub-channel 42
> > 00 00 00 00 00 00 00 18 00
> > [    4.011061] blk_update_request: I/O error, dev sda, sector 0
> > ---- [ snip ] ----
> > 
> > This turns out to be a result of a flaw in changes to the error value
> > translation logic in handle_aiocb_discard(). The default return value
> > may be left untranslated in some configurations, and the wrong variable
> > is used in one translation.
> > 
> > Fix both issues.
> 
> Worth including:
> 
> Cc: qemu-stable@nongnu.org
> Fixes: 0dfc7af2b28 ("block/file-posix: Optimize for macOS")
> 
> > Signed-off-by: Ari Sundholm <ari@tuxera.com>
> > Signed-off-by: Emil Karlson <jkarlson@tuxera.com>
> > ---
> >  block/file-posix.c | 4 ++--
> >  1 file changed, 2 insertions(+), 2 deletions(-)
> > 
> > diff --git a/block/file-posix.c b/block/file-posix.c
> > index 53be0bdc1b..6def2a4cba 100644
> > --- a/block/file-posix.c
> > +++ b/block/file-posix.c
> > @@ -1807,7 +1807,7 @@ static int handle_aiocb_copy_range(void *opaque)
> >  static int handle_aiocb_discard(void *opaque)
> >  {
> >      RawPosixAIOData *aiocb = opaque;
> > -    int ret = -EOPNOTSUPP;
> > +    int ret = -ENOTSUP;
> >      BDRVRawState *s = aiocb->bs->opaque;
> >  
> >      if (!s->has_discard) {
> > @@ -1829,7 +1829,7 @@ static int handle_aiocb_discard(void *opaque)
> >  #ifdef CONFIG_FALLOCATE_PUNCH_HOLE
> >          ret = do_fallocate(s->fd, FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE,
> >                             aiocb->aio_offset, aiocb->aio_nbytes);
> > -        ret = translate_err(-errno);
> > +        ret = translate_err(ret);
> >  #elif defined(__APPLE__) && (__MACH__)
> >          fpunchhole_t fpunchhole;
> >          fpunchhole.fp_flags = 0;
> > 
> 

Thanks for the fix!

Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>

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