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

[Philippe Mathieu-Daudé]

+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;
>