On 09/15/2010 11:06 AM, Juan Quintela wrote:
Anthony Liguori<aligu...@us.ibm.com> wrote:
The use of protocols in backing_files is currently broken because of some
checks for adjusting relative pathnames.
Additionally, there's a spurious read when using an nbd protocol that can be
quite destructive when using copy-on-read. Potentially, this can lead to
probing an image file over top of NBD but this is completely wrong as NBD
devices are not growable.
Signed-off-by: Anthony Liguori<aligu...@us.ibm.com>
---
NB: this is absolutely not ideal. A more elegant suggestion would be
appreciated. I don't think NBD cleanly fits the model of a protocol as it
stands today.
Bad, bad boy, you fixed two things in a single patch.
You're not supposed to notice that :-) It was an RFC series, I was
really just looking to start a conversation.
@@ -603,10 +610,16 @@ int bdrv_open(BlockDriverState *bs, const char *filename,
int flags,
BlockDriver *back_drv = NULL;
bs->backing_hd = bdrv_new("");
- path_combine(backing_filename, sizeof(backing_filename),
- filename, bs->backing_file);
- if (bs->backing_format[0] != '\0')
- back_drv = bdrv_find_format(bs->backing_format);
+ back_drv = bdrv_find_protocol(bs->backing_file);
+ if (!back_drv) {
+ path_combine(backing_filename, sizeof(backing_filename),
+ filename, bs->backing_file);
+ if (bs->backing_format[0] != '\0')
+ back_drv = bdrv_find_format(bs->backing_format);
+ } else {
+ pstrcpy(backing_filename, sizeof(backing_filename),
+ bs->backing_file);
+ }
/* backing files always opened read-only */
back_flags =
But this one breaks my setup, I have to backout this patch to be able to
launch guests with qcow2 file images.
Kevin, do you have an opinion about the best way to resolve this?
The relative/absolute path is broken for non-file URIs. I think we
could mark a protocol as having a file URI type or we could push the
absolute/relative conversion down to the file/phys_dev protocol.
I think the former approach is probably the least invasive.
Regards,
Anthony LIguori
Later, Juan.
