block: Add bdrv_set_backing_hd()

This is the common but non-trivial steps to assign or change the
backing_hd of BDS.

Signed-off-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Jeff Cody <jcody@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
This commit is contained in:
Fam Zheng 2014-05-23 21:29:45 +08:00 committed by Stefan Hajnoczi
parent 628ff68303
commit 8d24cce1e3
2 changed files with 24 additions and 13 deletions

36
block.c
View File

@ -1094,6 +1094,21 @@ fail:
return ret;
}
void bdrv_set_backing_hd(BlockDriverState *bs, BlockDriverState *backing_hd)
{
bs->backing_hd = backing_hd;
if (!backing_hd) {
goto out;
}
bs->open_flags &= ~BDRV_O_NO_BACKING;
pstrcpy(bs->backing_file, sizeof(bs->backing_file), backing_hd->filename);
pstrcpy(bs->backing_format, sizeof(bs->backing_format),
backing_hd->drv ? backing_hd->drv->format_name : "");
out:
bdrv_refresh_limits(bs);
}
/*
* Opens the backing file for a BlockDriverState if not yet open
*
@ -1107,6 +1122,7 @@ int bdrv_open_backing_file(BlockDriverState *bs, QDict *options, Error **errp)
char *backing_filename = g_malloc0(PATH_MAX);
int ret = 0;
BlockDriver *back_drv = NULL;
BlockDriverState *backing_hd;
Error *local_err = NULL;
if (bs->backing_hd != NULL) {
@ -1129,27 +1145,26 @@ int bdrv_open_backing_file(BlockDriverState *bs, QDict *options, Error **errp)
bdrv_get_full_backing_filename(bs, backing_filename, PATH_MAX);
}
backing_hd = bdrv_new("", errp);
if (bs->backing_format[0] != '\0') {
back_drv = bdrv_find_format(bs->backing_format);
}
assert(bs->backing_hd == NULL);
ret = bdrv_open(&bs->backing_hd,
ret = bdrv_open(&backing_hd,
*backing_filename ? backing_filename : NULL, NULL, options,
bdrv_backing_flags(bs->open_flags), back_drv, &local_err);
if (ret < 0) {
bs->backing_hd = NULL;
bdrv_unref(backing_hd);
backing_hd = NULL;
bs->open_flags |= BDRV_O_NO_BACKING;
error_setg(errp, "Could not open backing file: %s",
error_get_pretty(local_err));
error_free(local_err);
goto free_exit;
}
if (bs->backing_hd->file) {
pstrcpy(bs->backing_file, sizeof(bs->backing_file),
bs->backing_hd->file->filename);
}
bdrv_set_backing_hd(bs, backing_hd);
/* Recalculate the BlockLimits with the backing file */
bdrv_refresh_limits(bs);
@ -2043,12 +2058,7 @@ void bdrv_append(BlockDriverState *bs_new, BlockDriverState *bs_top)
/* The contents of 'tmp' will become bs_top, as we are
* swapping bs_new and bs_top contents. */
bs_top->backing_hd = bs_new;
bs_top->open_flags &= ~BDRV_O_NO_BACKING;
pstrcpy(bs_top->backing_file, sizeof(bs_top->backing_file),
bs_new->filename);
pstrcpy(bs_top->backing_format, sizeof(bs_top->backing_format),
bs_new->drv ? bs_new->drv->format_name : "");
bdrv_set_backing_hd(bs_top, bs_new);
}
static void bdrv_delete(BlockDriverState *bs)

View File

@ -216,6 +216,7 @@ int bdrv_parse_discard_flags(const char *mode, int *flags);
int bdrv_open_image(BlockDriverState **pbs, const char *filename,
QDict *options, const char *bdref_key, int flags,
bool allow_none, Error **errp);
void bdrv_set_backing_hd(BlockDriverState *bs, BlockDriverState *backing_hd);
int bdrv_open_backing_file(BlockDriverState *bs, QDict *options, Error **errp);
void bdrv_append_temp_snapshot(BlockDriverState *bs, int flags, Error **errp);
int bdrv_open(BlockDriverState **pbs, const char *filename,