mirror of
https://gitlab.com/qemu-project/qemu
synced 2024-09-06 18:05:37 +00:00
block: move has_variable_length to BlockLimits
At the protocol level, has_variable_length only needs to be true in the very special case of host CD-ROM drives, so that they do not need an explicit monitor command to read the new size when a disc is loaded in the tray. However, at the format level has_variable_length has to be true for all raw blockdevs and for all filters, even though in practice the length depends on the underlying file and thus will not change except in the case of host CD-ROM drives. As a first step towards computing an accurate value of has_variable_length, add the value into the BlockLimits structure and initialize the field from the BlockDriver. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Message-Id: <20230407153303.391121-2-pbonzini@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
parent
2b1f8fcb84
commit
160a29e2f8
2
block.c
2
block.c
|
@ -5849,7 +5849,7 @@ int64_t coroutine_fn bdrv_co_nb_sectors(BlockDriverState *bs)
|
||||||
if (!drv)
|
if (!drv)
|
||||||
return -ENOMEDIUM;
|
return -ENOMEDIUM;
|
||||||
|
|
||||||
if (drv->has_variable_length) {
|
if (bs->bl.has_variable_length) {
|
||||||
int ret = bdrv_co_refresh_total_sectors(bs, bs->total_sectors);
|
int ret = bdrv_co_refresh_total_sectors(bs, bs->total_sectors);
|
||||||
if (ret < 0) {
|
if (ret < 0) {
|
||||||
return ret;
|
return ret;
|
||||||
|
|
|
@ -182,6 +182,8 @@ void bdrv_refresh_limits(BlockDriverState *bs, Transaction *tran, Error **errp)
|
||||||
drv->bdrv_aio_preadv ||
|
drv->bdrv_aio_preadv ||
|
||||||
drv->bdrv_co_preadv_part) ? 1 : 512;
|
drv->bdrv_co_preadv_part) ? 1 : 512;
|
||||||
|
|
||||||
|
bs->bl.has_variable_length = drv->has_variable_length;
|
||||||
|
|
||||||
/* Take some limits from the children as a default */
|
/* Take some limits from the children as a default */
|
||||||
have_limits = false;
|
have_limits = false;
|
||||||
QLIST_FOREACH(c, &bs->children, next) {
|
QLIST_FOREACH(c, &bs->children, next) {
|
||||||
|
@ -190,6 +192,10 @@ void bdrv_refresh_limits(BlockDriverState *bs, Transaction *tran, Error **errp)
|
||||||
bdrv_merge_limits(&bs->bl, &c->bs->bl);
|
bdrv_merge_limits(&bs->bl, &c->bs->bl);
|
||||||
have_limits = true;
|
have_limits = true;
|
||||||
}
|
}
|
||||||
|
|
||||||
|
if (c->role & BDRV_CHILD_FILTERED) {
|
||||||
|
bs->bl.has_variable_length |= c->bs->bl.has_variable_length;
|
||||||
|
}
|
||||||
}
|
}
|
||||||
|
|
||||||
if (!have_limits) {
|
if (!have_limits) {
|
||||||
|
|
|
@ -855,6 +855,14 @@ typedef struct BlockLimits {
|
||||||
|
|
||||||
/* maximum number of iovec elements */
|
/* maximum number of iovec elements */
|
||||||
int max_iov;
|
int max_iov;
|
||||||
|
|
||||||
|
/*
|
||||||
|
* true if the length of the underlying file can change, and QEMU
|
||||||
|
* is expected to adjust automatically. Mostly for CD-ROM drives,
|
||||||
|
* whose length is zero when the tray is empty (they don't need
|
||||||
|
* an explicit monitor command to load the disk inside the guest).
|
||||||
|
*/
|
||||||
|
bool has_variable_length;
|
||||||
} BlockLimits;
|
} BlockLimits;
|
||||||
|
|
||||||
typedef struct BdrvOpBlocker BdrvOpBlocker;
|
typedef struct BdrvOpBlocker BdrvOpBlocker;
|
||||||
|
|
Loading…
Reference in a new issue