Commit 5634622bcb ("file-posix: allow BLKZEROOUT with -t writeback")
enables the BLKZEROOUT ioctl when using 'writeback' cache, regressing
certain 'qemu-img convert' invocations, because of a pre-existing
issue. Namely, the BLKZEROOUT ioctl might fail with errno EINVAL when
the request is shorter than the block size of the block device.
Fallback to the bounce buffer, similar to when the ioctl is not
supported at all, rather than treating such an error as fatal.Resolves: https://gitlab.com/qemu-project/qemu/-/issues/3257 Resolves: https://bugzilla.proxmox.com/show_bug.cgi?id=7197 Cc: [email protected] Signed-off-by: Fiona Ebner <[email protected]> --- block/io.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/block/io.c b/block/io.c index cace297f22..e37d9d2417 100644 --- a/block/io.c +++ b/block/io.c @@ -1917,7 +1917,8 @@ bdrv_co_do_pwrite_zeroes(BlockDriverState *bs, int64_t offset, int64_t bytes, assert(!bs->supported_zero_flags); } - if (ret == -ENOTSUP && !(flags & BDRV_REQ_NO_FALLBACK)) { + if ((ret == -ENOTSUP || (ret == -EINVAL && num < alignment)) && + !(flags & BDRV_REQ_NO_FALLBACK)) { /* Fall back to bounce buffer if write zeroes is unsupported */ BdrvRequestFlags write_flags = flags & ~BDRV_REQ_ZERO_WRITE; -- 2.47.3
