From 8d24cce1e325c4bd47a8b1984d6db599f5a7a8e9 Mon Sep 17 00:00:00 2001 From: Fam Zheng Date: Fri, 23 May 2014 21:29:45 +0800 Subject: 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 Reviewed-by: Stefan Hajnoczi Reviewed-by: Jeff Cody Signed-off-by: Stefan Hajnoczi --- block.c | 36 +++++++++++++++++++++++------------- 1 file changed, 23 insertions(+), 13 deletions(-) (limited to 'block.c') diff --git a/block.c b/block.c index 64c48a54a1..911ba6816e 100644 --- a/block.c +++ b/block.c @@ -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) -- cgit v1.2.3