Re: [PATCH] block: allocate aligned write buffer for 'truncate -m full'

[Vladimir Sementsov-Ogievskiy]

On 11.12.23 13:55, Andrey Drobyshev wrote:

In case we're truncating an image opened with O_DIRECT, we might get
-EINVAL on write with unaligned buffer.  In particular, when running
iotests/298 with '-nocache' we get:

qemu-io: Failed to resize underlying file: Could not write zeros for
preallocation: Invalid argument

Let's just allocate the buffer using qemu_blockalign0() instead.

Signed-off-by: Andrey Drobyshev <andrey.drobys...@virtuozzo.com>

Reviewed-by: Vladimir Sementsov-Ogievskiy <vsement...@yandex-team.ru>

I also suggest to use QEMU_AUTO_VFREE (keep my r-b if you do).

---
  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 b862406c71..cee8de510b 100644
--- a/block/file-posix.c
+++ b/block/file-posix.c
@@ -2354,7 +2354,7 @@ static int handle_aiocb_truncate(void *opaque)
              goto out;
          }

- buf = g_malloc0(65536);

+        buf = qemu_blockalign0(aiocb->bs, 65536);

seek_result = lseek(fd, current_length, SEEK_SET);

          if (seek_result < 0) {
@@ -2413,7 +2413,7 @@ out:
          }
      }

- g_free(buf);

+    qemu_vfree(buf);
      return result;
  }

--
Best regards,
Vladimir