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* [Qemu-devel] [PATCH] block: workaround for unaligned byte range in fallocate()
@ 2019-08-22 18:31 Andrey Shinkevich
  2019-08-22 18:55 ` Vladimir Sementsov-Ogievskiy
  2019-08-22 21:09 ` Eric Blake
  0 siblings, 2 replies; 8+ messages in thread
From: Andrey Shinkevich @ 2019-08-22 18:31 UTC (permalink / raw)
  To: qemu-devel, qemu-block
  Cc: kwolf, fam, vsementsov, mreitz, stefanha, andrey.shinkevich, den

Revert the commit 118f99442d 'block/io.c: fix for the allocation failure'
and make better error handling for the file systems that do not support
fallocate() for the unaligned byte range. Allow falling back to pwrite
in case fallocate() returns EINVAL.

Suggested-by: Kevin Wolf <kwolf@redhat.com>
Suggested-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com>
---
Discussed in email thread with the message ID
<1554474244-553661-1-git-send-email-andrey.shinkevich@virtuozzo.com>

 block/file-posix.c | 7 +++++++
 block/io.c         | 2 +-
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/block/file-posix.c b/block/file-posix.c
index fbeb006..2c254ff 100644
--- a/block/file-posix.c
+++ b/block/file-posix.c
@@ -1588,6 +1588,13 @@ static int handle_aiocb_write_zeroes(void *opaque)
     if (s->has_write_zeroes) {
         int ret = do_fallocate(s->fd, FALLOC_FL_ZERO_RANGE,
                                aiocb->aio_offset, aiocb->aio_nbytes);
+        if (ret == -EINVAL) {
+            /*
+             * Allow falling back to pwrite for file systems that
+             * do not support fallocate() for unaligned byte range.
+             */
+            return -ENOTSUP;
+        }
         if (ret == 0 || ret != -ENOTSUP) {
             return ret;
         }
diff --git a/block/io.c b/block/io.c
index 56bbf19..58f08cd 100644
--- a/block/io.c
+++ b/block/io.c
@@ -1558,7 +1558,7 @@ static int coroutine_fn bdrv_co_do_pwrite_zeroes(BlockDriverState *bs,
             assert(!bs->supported_zero_flags);
         }
 
-        if (ret < 0 && !(flags & BDRV_REQ_NO_FALLBACK)) {
+        if (ret == -ENOTSUP && !(flags & BDRV_REQ_NO_FALLBACK)) {
             /* Fall back to bounce buffer if write zeroes is unsupported */
             BdrvRequestFlags write_flags = flags & ~BDRV_REQ_ZERO_WRITE;
 
-- 
1.8.3.1



^ permalink raw reply related	[flat|nested] 8+ messages in thread

end of thread, other threads:[~2019-08-27 13:51 UTC | newest]

Thread overview: 8+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2019-08-22 18:31 [Qemu-devel] [PATCH] block: workaround for unaligned byte range in fallocate() Andrey Shinkevich
2019-08-22 18:55 ` Vladimir Sementsov-Ogievskiy
2019-08-22 19:10   ` Vladimir Sementsov-Ogievskiy
2019-08-22 21:09 ` Eric Blake
2019-08-23 12:07   ` Andrey Shinkevich
2019-08-27 12:35   ` Denis V. Lunev
2019-08-27 12:39   ` Andrey Shinkevich
2019-08-27 13:50     ` Eric Blake

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