block/ssh: Set bdrv_has_zero_init according to the file type.
If the remote is a regular file, set it to true (ie. reads of
uninitialized areas in a newly created file will return zeroes).
If we can't prove that, return false (a safe default).
Tested by adding a debugging print statement [not part of this commit]
and creating a remote file and a remote block device:
$ ./qemu-img create ssh://localhost/tmp/new 100M
Formatting 'ssh://localhost/tmp/new', fmt=raw size=104857600
filename ssh://localhost/tmp/new: has_zero_init = 1
$ sudo lvcreate -L 1G -n tmp /dev/fedora
Logical volume "tmp" created
$ ./qemu-img create ssh://localhost/dev/fedora/tmp 1G
Formatting 'ssh://localhost/dev/fedora/tmp', fmt=raw size=1073741824
filename ssh://localhost/dev/fedora/tmp: has_zero_init = 0
Cc: Kevin Wolf <kwolf@redhat.com>
Cc: qemu-stable@nongnu.org
Signed-off-by: Richard W.M. Jones <rjones@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
diff --git a/block/ssh.c b/block/ssh.c
index 246a70d..d7e7bf8 100644
--- a/block/ssh.c
+++ b/block/ssh.c
@@ -716,6 +716,21 @@
ssh_state_free(s);
}
+static int ssh_has_zero_init(BlockDriverState *bs)
+{
+ BDRVSSHState *s = bs->opaque;
+ /* Assume false, unless we can positively prove it's true. */
+ int has_zero_init = 0;
+
+ if (s->attrs.flags & LIBSSH2_SFTP_ATTR_PERMISSIONS) {
+ if (s->attrs.permissions & LIBSSH2_SFTP_S_IFREG) {
+ has_zero_init = 1;
+ }
+ }
+
+ return has_zero_init;
+}
+
static void restart_coroutine(void *opaque)
{
Coroutine *co = opaque;
@@ -1037,6 +1052,7 @@
.bdrv_file_open = ssh_file_open,
.bdrv_create = ssh_create,
.bdrv_close = ssh_close,
+ .bdrv_has_zero_init = ssh_has_zero_init,
.bdrv_co_readv = ssh_co_readv,
.bdrv_co_writev = ssh_co_writev,
.bdrv_getlength = ssh_getlength,
