On 09/26/2012 11:56 AM, Paolo Bonzini wrote:
> Mirroring runs without the backing file so that it can be copied outside
> QEMU. However, we need to add it at the time the job is completed and
> QEMU switches to the target. Factor out the common bits of opening an
> image and completing a mirroring operation.
>
> The new function does not assume that the file is closed immediately after
> it returns failure, so it keeps the BDRV_O_NO_BACKING flag up-to-date.
>
> Signed-off-by: Paolo Bonzini <pbonz...@redhat.com>
> ---
> v1->v2: do not close bs if the function fails (brain fart).
>
> block.c | 62 ++++++++++++++++++++++++++++++++++++++++++++------------------
> block.h | 1 +
> 2 file modificati, 45 inserzioni(+), 18 rimozioni(-)
>
> diff --git a/block.c b/block.c
> index 703261d..6ee7052 100644
> --- a/block.c
> +++ b/block.c
> @@ -734,6 +734,48 @@ int bdrv_file_open(BlockDriverState **pbs, const char
> *filename, int flags)
> return 0;
> }
>
> +int bdrv_open_backing_file(BlockDriverState *bs)
> +{
> + char backing_filename[PATH_MAX];
> + int back_flags, ret;
> + BlockDriver *back_drv = NULL;
> +
> + if (bs->backing_hd != NULL) {
> + return 0;
> + }
> +
> + bs->open_flags &= ~BDRV_O_NO_BACKING;
> + if (bs->backing_file[0] == '\0') {
> + return 0;
> + }
> +
> + bs->backing_hd = bdrv_new("");
> + bdrv_get_full_backing_filename(bs, backing_filename,
> + sizeof(backing_filename));
> +
> + if (bs->backing_format[0] != '\0') {
> + back_drv = bdrv_find_format(bs->backing_format);
> + }
> +
> + /* backing files always opened read-only */
> + back_flags = bs->open_flags & ~(BDRV_O_RDWR | BDRV_O_SNAPSHOT);
> +
> + ret = bdrv_open(bs->backing_hd, backing_filename, back_flags, back_drv);
> + if (ret < 0) {
> + bdrv_delete(bs->backing_hd);
> + bs->backing_hd = NULL;
> + bs->open_flags |= BDRV_O_NO_BACKING;
> + return ret;
> + }
> + if (bs->is_temporary) {
> + bs->backing_hd->keep_read_only = !(bs->open_flags & BDRV_O_RDWR);
> + } else {
> + /* base images use the same setting as leaf */
> + bs->backing_hd->keep_read_only = bs->keep_read_only;
> + }
The bs->keep_read_only flag no longer exists. I think you can safely delete
the above 6 lines... BDRV_O_ALLOW_RDWR is now used instead, and will be
pulled in from bs->open_flags. (see commit be028ad and dc1c13d).
> + return 0;
> +}
> +
> /*
> * Opens a disk image (raw, qcow2, vmdk, ...)
> */
> @@ -821,24 +863,8 @@ int bdrv_open(BlockDriverState *bs, const char
> *filename, int flags,
> }
>
> /* If there is a backing file, use it */
> - if ((flags & BDRV_O_NO_BACKING) == 0 && bs->backing_file[0] != '\0') {
> - char backing_filename[PATH_MAX];
> - int back_flags;
> - BlockDriver *back_drv = NULL;
> -
> - bs->backing_hd = bdrv_new("");
> - bdrv_get_full_backing_filename(bs, backing_filename,
> - sizeof(backing_filename));
> -
> - if (bs->backing_format[0] != '\0') {
> - back_drv = bdrv_find_format(bs->backing_format);
> - }
> -
> - /* backing files always opened read-only */
> - back_flags =
> - flags & ~(BDRV_O_RDWR | BDRV_O_SNAPSHOT | BDRV_O_NO_BACKING);
> -
> - ret = bdrv_open(bs->backing_hd, backing_filename, back_flags,
> back_drv);
> + if ((flags & BDRV_O_NO_BACKING) == 0) {
> + ret = bdrv_open_backing_file(bs);
> if (ret < 0) {
> bdrv_close(bs);
> return ret;
> diff --git a/block.h b/block.h
> index aa1121a..08479e1 100644
> --- a/block.h
> +++ b/block.h
> @@ -133,6 +133,7 @@ void bdrv_append(BlockDriverState *bs_new,
> BlockDriverState *bs_top);
> void bdrv_delete(BlockDriverState *bs);
> int bdrv_parse_cache_flags(const char *mode, int *flags);
> int bdrv_file_open(BlockDriverState **pbs, const char *filename, int flags);
> +int bdrv_open_backing_file(BlockDriverState *bs);
> int bdrv_open(BlockDriverState *bs, const char *filename, int flags,
> BlockDriver *drv);
> BlockReopenQueue *bdrv_reopen_queue(BlockReopenQueue *bs_queue,
>
