On 2018-02-14 22:11, Eric Blake wrote:
> On 02/14/2018 02:49 PM, Max Reitz wrote:
>> At runtime (that is, during a future ssh_truncate()), the SSH session is
>> non-blocking. However, ssh_truncate() (or rather, bdrv_truncate() in
>> general) is not a coroutine, so this resize operation needs to block.
>>
>> For ssh_create(), that is fine, too; the session is never set to
>> non-blocking anyway.
>>
>> Signed-off-by: Max Reitz <mre...@redhat.com>
>> ---
>> block/ssh.c | 7 +++++++
>> 1 file changed, 7 insertions(+)
>>
>> diff --git a/block/ssh.c b/block/ssh.c
>> index 964e55f7fe..ff8576f21e 100644
>> --- a/block/ssh.c
>> +++ b/block/ssh.c
>> @@ -803,17 +803,24 @@ static int ssh_file_open(BlockDriverState *bs,
>> QDict *options, int bdrv_flags,
>> return ret;
>> }
>> +/* Note: This is a blocking operation */
>> static int ssh_grow_file(BDRVSSHState *s, int64_t offset, Error **errp)
>> {
>> ssize_t ret;
>> char c[1] = { '\0' };
>> + int was_blocking = libssh2_session_get_blocking(s->session);
>> /* offset must be strictly greater than the current size so we do
>> * not overwrite anything */
>> assert(offset > 0 && offset > s->attrs.filesize);
>> + libssh2_session_set_blocking(s->session, 1);
>> +
>> libssh2_sftp_seek64(s->sftp_handle, offset - 1);
>> ret = libssh2_sftp_write(s->sftp_handle, c, 1);
>> +
>> + libssh2_session_set_blocking(s->session, was_blocking);
>
> Is it worth skipping the two libssh2_session_set_blocking() calls if
> was_blocking is 1? But that's a micro-optimization that probably won't
> be noticeable, so I'm also fine with unconditional.I was hoping libssh2 is clever enough for that itself. :-) > Reviewed-by: Eric Blake <ebl...@redhat.com> Thanks! Max
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