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block: Allow reopen rw without BDRV_O_ALLOW_RDWR

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BDRV_O_ALLOW_RDWR is a flag that tells whether qemu can internally
reopen a node read-write temporarily because the user requested
read-write for the top-level image, but qemu decided that read-only is
enough for this node (a backing file).

bdrv_reopen() is different, it is also used for cases where the user
changed their mind and wants to update the options. There is no reason
to forbid making a node read-write in that case.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Jeff Cody <jcody@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
This commit is contained in:
Kevin Wolf 2017-08-03 17:02:58 +02:00
parent 8aecf1d1bd
commit 54a32bfec1
2 changed files with 9 additions and 5 deletions
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11
block.c
View File

@ -246,7 +246,8 @@ bool bdrv_is_writable(BlockDriverState *bs)
return !bdrv_is_read_only(bs) && !(bs->open_flags & BDRV_O_INACTIVE);
}
int bdrv_can_set_read_only(BlockDriverState *bs, bool read_only, Error **errp)
int bdrv_can_set_read_only(BlockDriverState *bs, bool read_only,
bool ignore_allow_rdw, Error **errp)
{
/* Do not set read_only if copy_on_read is enabled */
if (bs->copy_on_read && read_only) {
@ -256,7 +257,9 @@ int bdrv_can_set_read_only(BlockDriverState *bs, bool read_only, Error **errp)
}
/* Do not clear read_only if it is prohibited */
if (!read_only && !(bs->open_flags & BDRV_O_ALLOW_RDWR)) {
if (!read_only && !(bs->open_flags & BDRV_O_ALLOW_RDWR) &&
!ignore_allow_rdw)
{
error_setg(errp, "Node '%s' is read only",
bdrv_get_device_or_node_name(bs));
return -EPERM;
@ -269,7 +272,7 @@ int bdrv_set_read_only(BlockDriverState *bs, bool read_only, Error **errp)
{
int ret = 0;
ret = bdrv_can_set_read_only(bs, read_only, errp);
ret = bdrv_can_set_read_only(bs, read_only, false, errp);
if (ret < 0) {
return ret;
}
@ -2907,7 +2910,7 @@ int bdrv_reopen_prepare(BDRVReopenState *reopen_state, BlockReopenQueue *queue,
* to r/w. Attempting to set to r/w may fail if either BDRV_O_ALLOW_RDWR is
* not set, or if the BDS still has copy_on_read enabled */
read_only = !(reopen_state->flags & BDRV_O_RDWR);
ret = bdrv_can_set_read_only(reopen_state->bs, read_only, &local_err);
ret = bdrv_can_set_read_only(reopen_state->bs, read_only, true, &local_err);
if (local_err) {
error_propagate(errp, local_err);
goto error;

3
include/block/block.h
View File

@ -436,7 +436,8 @@ int bdrv_is_allocated_above(BlockDriverState *top, BlockDriverState *base,
bool bdrv_is_read_only(BlockDriverState *bs);
bool bdrv_is_writable(BlockDriverState *bs);
int bdrv_can_set_read_only(BlockDriverState *bs, bool read_only, Error **errp);
int bdrv_can_set_read_only(BlockDriverState *bs, bool read_only,
bool ignore_allow_rdw, Error **errp);
int bdrv_set_read_only(BlockDriverState *bs, bool read_only, Error **errp);
bool bdrv_is_sg(BlockDriverState *bs);
bool bdrv_is_inserted(BlockDriverState *bs);