From: "Denis V. Lunev" <d...@openvz.org>
Original idea beyond the code in question was the following: we have failed
to write zeroes with fallocate(FALLOC_FL_ZERO_RANGE) as the simplest
approach and via fallocate(FALLOC_FL_PUNCH_HOLE)/fallocate(0). We have the
only chance now: if the request comes beyond end of the file. Thus we
should calculate file length and respect the error code from that op.
Signed-off-by: Denis V. Lunev <d...@openvz.org>
CC: Markus Armbruster <arm...@redhat.com>
CC: Kevin Wolf <kw...@redhat.com>
CC: Max Reitz <mre...@redhat.com>
CC: Stefan Hajnoczi <stefa...@redhat.com>
Signed-off-by: Kevin Wolf <kw...@redhat.com>
Reviewed-by: Eric Blake <ebl...@redhat.com>
---
block/file-posix.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/block/file-posix.c b/block/file-posix.c
index cfbb236f6f..f4de022ae0 100644
--- a/block/file-posix.c
+++ b/block/file-posix.c
@@ -1339,6 +1339,9 @@ static ssize_t handle_aiocb_write_zeroes(RawPosixAIOData
*aiocb)
#if defined(CONFIG_FALLOCATE) || defined(CONFIG_XFS)
BDRVRawState *s = aiocb->bs->opaque;
#endif
+#ifdef CONFIG_FALLOCATE
+ int64_t len;
+#endif
if (aiocb->aio_type & QEMU_AIO_BLKDEV) {
return handle_aiocb_write_zeroes_block(aiocb);
@@ -1381,7 +1384,10 @@ static ssize_t handle_aiocb_write_zeroes(RawPosixAIOData
*aiocb)
#endif
#ifdef CONFIG_FALLOCATE
- if (s->has_fallocate && aiocb->aio_offset >= bdrv_getlength(aiocb->bs)) {
+ /* Last resort: we are trying to extend the file with zeroed data. This
+ * can be done via fallocate(fd, 0) */
+ len = bdrv_getlength(aiocb->bs);
+ if (s->has_fallocate && len >= 0 && aiocb->aio_offset >= len) {
int ret = do_fallocate(s->fd, 0, aiocb->aio_offset, aiocb->aio_nbytes);
if (ret == 0 || ret != -ENOTSUP) {
return ret;
--
2.13.4
