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author | Max Reitz <mreitz@redhat.com> | 2020-04-29 16:11:23 +0200 |
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committer | Kevin Wolf <kwolf@redhat.com> | 2020-05-18 19:05:25 +0200 |
commit | 6f7a3b535f0d48d138e43cadf13323f083bfb547 (patch) | |
tree | a29836b6ac0b907aa5dd7609fdceca23bde047bb /block.c | |
parent | 19b7868eff865c01985a5d37f1c9c0c8691b0001 (diff) | |
download | qemu-6f7a3b535f0d48d138e43cadf13323f083bfb547.zip qemu-6f7a3b535f0d48d138e43cadf13323f083bfb547.tar.gz qemu-6f7a3b535f0d48d138e43cadf13323f083bfb547.tar.bz2 |
block: Add bdrv_make_empty()
Right now, all users of bdrv_make_empty() call the BlockDriver method
directly. That is not only bad style, it is also wrong, unless the
caller has a BdrvChild with a WRITE or WRITE_UNCHANGED permission.
(WRITE_UNCHANGED suffices, because callers generally use this function
to clear a node with a backing file after a commit operation.)
Introduce bdrv_make_empty() that verifies that it does.
Signed-off-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20200429141126.85159-2-mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Diffstat (limited to 'block.c')
-rw-r--r-- | block.c | 23 |
1 files changed, 23 insertions, 0 deletions
@@ -6764,3 +6764,26 @@ void bdrv_del_child(BlockDriverState *parent_bs, BdrvChild *child, Error **errp) parent_bs->drv->bdrv_del_child(parent_bs, child, errp); } + +int bdrv_make_empty(BdrvChild *c, Error **errp) +{ + BlockDriver *drv = c->bs->drv; + int ret; + + assert(c->perm & (BLK_PERM_WRITE | BLK_PERM_WRITE_UNCHANGED)); + + if (!drv->bdrv_make_empty) { + error_setg(errp, "%s does not support emptying nodes", + drv->format_name); + return -ENOTSUP; + } + + ret = drv->bdrv_make_empty(c->bs); + if (ret < 0) { + error_setg_errno(errp, -ret, "Failed to empty %s", + c->bs->filename); + return ret; + } + + return 0; +} |