[v5] block: file-posix queue

[PATCH 11/11] file-posix: handle EINTR during ioctl

Posted by Paolo Bonzini 4 years, 7 months ago

Similar to other handle_aiocb_* functions, handle_aiocb_ioctl needs to cater
for the possibility that ioctl is interrupted by a signal.  Otherwise, the
I/O is incorrectly reported as a failure to the guest.

Reported-by: Gordon Watson <gwatson@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 block/file-posix.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/block/file-posix.c b/block/file-posix.c
index 74b8216077..a26eab0ac3 100644
--- a/block/file-posix.c
+++ b/block/file-posix.c
@@ -1347,7 +1347,9 @@ static int handle_aiocb_ioctl(void *opaque)
     RawPosixAIOData *aiocb = opaque;
     int ret;
 
-    ret = ioctl(aiocb->aio_fildes, aiocb->ioctl.cmd, aiocb->ioctl.buf);
+    do {
+        ret = ioctl(aiocb->aio_fildes, aiocb->ioctl.cmd, aiocb->ioctl.buf);
+    } while (ret == -1 && errno == EINTR);
     if (ret == -1) {
         return -errno;
     }
-- 
2.31.1

Re: [PATCH 11/11] file-posix: handle EINTR during ioctl

Posted by Philippe Mathieu-Daudé 4 years, 7 months ago

On 6/24/21 8:04 PM, Paolo Bonzini wrote:
> Similar to other handle_aiocb_* functions, handle_aiocb_ioctl needs to cater
> for the possibility that ioctl is interrupted by a signal.  Otherwise, the
> I/O is incorrectly reported as a failure to the guest.
> 
> Reported-by: Gordon Watson <gwatson@redhat.com>
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> ---
>  block/file-posix.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/block/file-posix.c b/block/file-posix.c
> index 74b8216077..a26eab0ac3 100644
> --- a/block/file-posix.c
> +++ b/block/file-posix.c
> @@ -1347,7 +1347,9 @@ static int handle_aiocb_ioctl(void *opaque)
>      RawPosixAIOData *aiocb = opaque;
>      int ret;
>  
> -    ret = ioctl(aiocb->aio_fildes, aiocb->ioctl.cmd, aiocb->ioctl.buf);
> +    do {
> +        ret = ioctl(aiocb->aio_fildes, aiocb->ioctl.cmd, aiocb->ioctl.buf);
> +    } while (ret == -1 && errno == EINTR);

Shouldn't this use the TFR macro instead?

>      if (ret == -1) {
>          return -errno;
>      }
>

Re: [PATCH 11/11] file-posix: handle EINTR during ioctl

Posted by Max Reitz 4 years, 7 months ago

On 24.06.21 20:04, Paolo Bonzini wrote:
> Similar to other handle_aiocb_* functions, handle_aiocb_ioctl needs to cater
> for the possibility that ioctl is interrupted by a signal.  Otherwise, the
> I/O is incorrectly reported as a failure to the guest.
>
> Reported-by: Gordon Watson <gwatson@redhat.com>
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> ---
>   block/file-posix.c | 4 +++-
>   1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/block/file-posix.c b/block/file-posix.c
> index 74b8216077..a26eab0ac3 100644
> --- a/block/file-posix.c
> +++ b/block/file-posix.c
> @@ -1347,7 +1347,9 @@ static int handle_aiocb_ioctl(void *opaque)
>       RawPosixAIOData *aiocb = opaque;
>       int ret;
>   
> -    ret = ioctl(aiocb->aio_fildes, aiocb->ioctl.cmd, aiocb->ioctl.buf);
> +    do {
> +        ret = ioctl(aiocb->aio_fildes, aiocb->ioctl.cmd, aiocb->ioctl.buf);
> +    } while (ret == -1 && errno == EINTR);
>       if (ret == -1) {
>           return -errno;
>       }

I think the macro TFR() from qemu-common.h could be applied here, 
probably like `TFR(ret = ioctl(...));`.

No matter:

Reviewed-by: Max Reitz <mreitz@redhat.com>