block: Avoid bs->blk in bdrv_next()

We need to introduce a separate BdrvNextIterator struct that can keep
more state than just the current BDS in order to avoid using the bs->blk
pointer.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
This commit is contained in:
Kevin Wolf 2016-03-22 18:58:50 +01:00
parent dde33812a8
commit 7c8eece45b
10 changed files with 103 additions and 76 deletions

40
block.c
View File

@ -2870,25 +2870,6 @@ BlockDriverState *bdrv_next_node(BlockDriverState *bs)
return QTAILQ_NEXT(bs, node_list);
}
/* Iterates over all top-level BlockDriverStates, i.e. BDSs that are owned by
* the monitor or attached to a BlockBackend */
BlockDriverState *bdrv_next(BlockDriverState *bs)
{
if (!bs || bs->blk) {
bs = blk_next_root_bs(bs);
if (bs) {
return bs;
}
}
/* Ignore all BDSs that are attached to a BlockBackend here; they have been
* handled by the above block already */
do {
bs = bdrv_next_monitor_owned(bs);
} while (bs && bs->blk);
return bs;
}
const char *bdrv_get_node_name(const BlockDriverState *bs)
{
return bs->node_name;
@ -3220,10 +3201,11 @@ void bdrv_invalidate_cache(BlockDriverState *bs, Error **errp)
void bdrv_invalidate_cache_all(Error **errp)
{
BlockDriverState *bs = NULL;
BlockDriverState *bs;
Error *local_err = NULL;
BdrvNextIterator *it = NULL;
while ((bs = bdrv_next(bs)) != NULL) {
while ((it = bdrv_next(it, &bs)) != NULL) {
AioContext *aio_context = bdrv_get_aio_context(bs);
aio_context_acquire(aio_context);
@ -3265,10 +3247,11 @@ static int bdrv_inactivate_recurse(BlockDriverState *bs,
int bdrv_inactivate_all(void)
{
BlockDriverState *bs = NULL;
BdrvNextIterator *it = NULL;
int ret = 0;
int pass;
while ((bs = bdrv_next(bs)) != NULL) {
while ((it = bdrv_next(it, &bs)) != NULL) {
aio_context_acquire(bdrv_get_aio_context(bs));
}
@ -3277,8 +3260,8 @@ int bdrv_inactivate_all(void)
* the second pass sets the BDRV_O_INACTIVE flag so that no further write
* is allowed. */
for (pass = 0; pass < 2; pass++) {
bs = NULL;
while ((bs = bdrv_next(bs)) != NULL) {
it = NULL;
while ((it = bdrv_next(it, &bs)) != NULL) {
ret = bdrv_inactivate_recurse(bs, pass);
if (ret < 0) {
goto out;
@ -3287,8 +3270,8 @@ int bdrv_inactivate_all(void)
}
out:
bs = NULL;
while ((bs = bdrv_next(bs)) != NULL) {
it = NULL;
while ((it = bdrv_next(it, &bs)) != NULL) {
aio_context_release(bdrv_get_aio_context(bs));
}
@ -3781,10 +3764,11 @@ bool bdrv_recurse_is_first_non_filter(BlockDriverState *bs,
*/
bool bdrv_is_first_non_filter(BlockDriverState *candidate)
{
BlockDriverState *bs = NULL;
BlockDriverState *bs;
BdrvNextIterator *it = NULL;
/* walk down the bs forest recursively */
while ((bs = bdrv_next(bs)) != NULL) {
while ((it = bdrv_next(it, &bs)) != NULL) {
bool perm;
/* try to recurse in this top level bs */

View File

@ -75,6 +75,7 @@ static const AIOCBInfo block_backend_aiocb_info = {
};
static void drive_info_del(DriveInfo *dinfo);
static BlockBackend *bdrv_first_blk(BlockDriverState *bs);
/* All BlockBackends */
static QTAILQ_HEAD(, BlockBackend) block_backends =
@ -286,28 +287,50 @@ BlockBackend *blk_next(BlockBackend *blk)
: QTAILQ_FIRST(&monitor_block_backends);
}
/*
* Iterates over all BlockDriverStates which are attached to a BlockBackend.
* This function is for use by bdrv_next().
*
* @bs must be NULL or a BDS that is attached to a BB.
*/
BlockDriverState *blk_next_root_bs(BlockDriverState *bs)
{
struct BdrvNextIterator {
enum {
BDRV_NEXT_BACKEND_ROOTS,
BDRV_NEXT_MONITOR_OWNED,
} phase;
BlockBackend *blk;
BlockDriverState *bs;
};
if (bs) {
assert(bs->blk);
blk = bs->blk;
} else {
blk = NULL;
/* Iterates over all top-level BlockDriverStates, i.e. BDSs that are owned by
* the monitor or attached to a BlockBackend */
BdrvNextIterator *bdrv_next(BdrvNextIterator *it, BlockDriverState **bs)
{
if (!it) {
it = g_new(BdrvNextIterator, 1);
*it = (BdrvNextIterator) {
.phase = BDRV_NEXT_BACKEND_ROOTS,
};
}
do {
blk = blk_all_next(blk);
} while (blk && !blk->root);
/* First, return all root nodes of BlockBackends. In order to avoid
* returning a BDS twice when multiple BBs refer to it, we only return it
* if the BB is the first one in the parent list of the BDS. */
if (it->phase == BDRV_NEXT_BACKEND_ROOTS) {
do {
it->blk = blk_all_next(it->blk);
*bs = it->blk ? blk_bs(it->blk) : NULL;
} while (it->blk && (*bs == NULL || bdrv_first_blk(*bs) != it->blk));
return blk ? blk->root->bs : NULL;
if (*bs) {
return it;
}
it->phase = BDRV_NEXT_MONITOR_OWNED;
}
/* Then return the monitor-owned BDSes without a BB attached. Ignore all
* BDSes that are attached to a BlockBackend here; they have been handled
* by the above block already */
do {
it->bs = bdrv_next_monitor_owned(it->bs);
*bs = it->bs;
} while (*bs && bdrv_has_blk(*bs));
return *bs ? it : NULL;
}
/*
@ -394,21 +417,26 @@ BlockDriverState *blk_bs(BlockBackend *blk)
return blk->root ? blk->root->bs : NULL;
}
/*
* Returns true if @bs has an associated BlockBackend.
*/
bool bdrv_has_blk(BlockDriverState *bs)
static BlockBackend *bdrv_first_blk(BlockDriverState *bs)
{
BdrvChild *child;
QLIST_FOREACH(child, &bs->parents, next_parent) {
if (child->role == &child_root) {
assert(bs->blk);
return true;
return child->opaque;
}
}
assert(!bs->blk);
return false;
return NULL;
}
/*
* Returns true if @bs has an associated BlockBackend.
*/
bool bdrv_has_blk(BlockDriverState *bs)
{
return bdrv_first_blk(bs) != NULL;
}
/*

View File

@ -270,10 +270,11 @@ void bdrv_drain_all(void)
{
/* Always run first iteration so any pending completion BHs run */
bool busy = true;
BlockDriverState *bs = NULL;
BlockDriverState *bs;
BdrvNextIterator *it = NULL;
GSList *aio_ctxs = NULL, *ctx;
while ((bs = bdrv_next(bs))) {
while ((it = bdrv_next(it, &bs))) {
AioContext *aio_context = bdrv_get_aio_context(bs);
aio_context_acquire(aio_context);
@ -301,10 +302,10 @@ void bdrv_drain_all(void)
for (ctx = aio_ctxs; ctx != NULL; ctx = ctx->next) {
AioContext *aio_context = ctx->data;
bs = NULL;
it = NULL;
aio_context_acquire(aio_context);
while ((bs = bdrv_next(bs))) {
while ((it = bdrv_next(it, &bs))) {
if (aio_context == bdrv_get_aio_context(bs)) {
if (bdrv_requests_pending(bs)) {
busy = true;
@ -317,8 +318,8 @@ void bdrv_drain_all(void)
}
}
bs = NULL;
while ((bs = bdrv_next(bs))) {
it = NULL;
while ((it = bdrv_next(it, &bs))) {
AioContext *aio_context = bdrv_get_aio_context(bs);
aio_context_acquire(aio_context);

View File

@ -373,9 +373,10 @@ int bdrv_snapshot_load_tmp_by_id_or_name(BlockDriverState *bs,
bool bdrv_all_can_snapshot(BlockDriverState **first_bad_bs)
{
bool ok = true;
BlockDriverState *bs = NULL;
BlockDriverState *bs;
BdrvNextIterator *it = NULL;
while (ok && (bs = bdrv_next(bs))) {
while (ok && (it = bdrv_next(it, &bs))) {
AioContext *ctx = bdrv_get_aio_context(bs);
aio_context_acquire(ctx);
@ -393,10 +394,11 @@ int bdrv_all_delete_snapshot(const char *name, BlockDriverState **first_bad_bs,
Error **err)
{
int ret = 0;
BlockDriverState *bs = NULL;
BlockDriverState *bs;
BdrvNextIterator *it = NULL;
QEMUSnapshotInfo sn1, *snapshot = &sn1;
while (ret == 0 && (bs = bdrv_next(bs))) {
while (ret == 0 && (it = bdrv_next(it, &bs))) {
AioContext *ctx = bdrv_get_aio_context(bs);
aio_context_acquire(ctx);
@ -415,9 +417,10 @@ int bdrv_all_delete_snapshot(const char *name, BlockDriverState **first_bad_bs,
int bdrv_all_goto_snapshot(const char *name, BlockDriverState **first_bad_bs)
{
int err = 0;
BlockDriverState *bs = NULL;
BlockDriverState *bs;
BdrvNextIterator *it = NULL;
while (err == 0 && (bs = bdrv_next(bs))) {
while (err == 0 && (it = bdrv_next(it, &bs))) {
AioContext *ctx = bdrv_get_aio_context(bs);
aio_context_acquire(ctx);
@ -435,9 +438,10 @@ int bdrv_all_find_snapshot(const char *name, BlockDriverState **first_bad_bs)
{
QEMUSnapshotInfo sn;
int err = 0;
BlockDriverState *bs = NULL;
BlockDriverState *bs;
BdrvNextIterator *it = NULL;
while (err == 0 && (bs = bdrv_next(bs))) {
while (err == 0 && (it = bdrv_next(it, &bs))) {
AioContext *ctx = bdrv_get_aio_context(bs);
aio_context_acquire(ctx);
@ -457,9 +461,10 @@ int bdrv_all_create_snapshot(QEMUSnapshotInfo *sn,
BlockDriverState **first_bad_bs)
{
int err = 0;
BlockDriverState *bs = NULL;
BlockDriverState *bs;
BdrvNextIterator *it = NULL;
while (err == 0 && (bs = bdrv_next(bs))) {
while (err == 0 && (it = bdrv_next(it, &bs))) {
AioContext *ctx = bdrv_get_aio_context(bs);
aio_context_acquire(ctx);
@ -480,9 +485,10 @@ int bdrv_all_create_snapshot(QEMUSnapshotInfo *sn,
BlockDriverState *bdrv_all_find_vmstate_bs(void)
{
bool not_found = true;
BlockDriverState *bs = NULL;
BlockDriverState *bs;
BdrvNextIterator *it = NULL;
while (not_found && (bs = bdrv_next(bs))) {
while (not_found && (it = bdrv_next(it, &bs))) {
AioContext *ctx = bdrv_get_aio_context(bs);
aio_context_acquire(ctx);

View File

@ -4135,8 +4135,9 @@ BlockJobInfoList *qmp_query_block_jobs(Error **errp)
{
BlockJobInfoList *head = NULL, **p_next = &head;
BlockDriverState *bs;
BdrvNextIterator *it = NULL;
for (bs = bdrv_next(NULL); bs; bs = bdrv_next(bs)) {
while ((it = bdrv_next(it, &bs))) {
AioContext *aio_context = bdrv_get_aio_context(bs);
aio_context_acquire(aio_context);

View File

@ -17,6 +17,7 @@ typedef struct BlockJob BlockJob;
typedef struct BdrvChild BdrvChild;
typedef struct BdrvChildRole BdrvChildRole;
typedef struct BlockJobTxn BlockJobTxn;
typedef struct BdrvNextIterator BdrvNextIterator;
typedef struct BlockDriverInfo {
/* in bytes, 0 if irrelevant */
@ -401,7 +402,7 @@ BlockDriverState *bdrv_lookup_bs(const char *device,
Error **errp);
bool bdrv_chain_contains(BlockDriverState *top, BlockDriverState *base);
BlockDriverState *bdrv_next_node(BlockDriverState *bs);
BlockDriverState *bdrv_next(BlockDriverState *bs);
BdrvNextIterator *bdrv_next(BdrvNextIterator *it, BlockDriverState **bs);
BlockDriverState *bdrv_next_monitor_owned(BlockDriverState *bs);
int bdrv_is_encrypted(BlockDriverState *bs);
int bdrv_key_required(BlockDriverState *bs);

View File

@ -89,7 +89,6 @@ void blk_remove_all_bs(void);
const char *blk_name(BlockBackend *blk);
BlockBackend *blk_by_name(const char *name);
BlockBackend *blk_next(BlockBackend *blk);
BlockDriverState *blk_next_root_bs(BlockDriverState *bs);
bool monitor_add_blk(BlockBackend *blk, const char *name, Error **errp);
void monitor_remove_blk(BlockBackend *blk);

View File

@ -383,6 +383,7 @@ static void init_blk_migration(QEMUFile *f)
BlockDriverState *bs;
BlkMigDevState *bmds;
int64_t sectors;
BdrvNextIterator *it = NULL;
block_mig_state.submitted = 0;
block_mig_state.read_done = 0;
@ -392,7 +393,8 @@ static void init_blk_migration(QEMUFile *f)
block_mig_state.bulk_completed = 0;
block_mig_state.zero_blocks = migrate_zero_blocks();
for (bs = bdrv_next(NULL); bs; bs = bdrv_next(bs)) {
while ((it = bdrv_next(it, &bs))) {
if (bdrv_is_read_only(bs)) {
continue;
}

View File

@ -3427,11 +3427,13 @@ void host_net_remove_completion(ReadLineState *rs, int nb_args, const char *str)
static void vm_completion(ReadLineState *rs, const char *str)
{
size_t len;
BlockDriverState *bs = NULL;
BlockDriverState *bs;
BdrvNextIterator *it = NULL;
len = strlen(str);
readline_set_completion_index(rs, len);
while ((bs = bdrv_next(bs))) {
while ((it = bdrv_next(it, &bs))) {
SnapshotInfoList *snapshots, *snapshot;
AioContext *ctx = bdrv_get_aio_context(bs);
bool ok = false;

5
qmp.c
View File

@ -181,6 +181,7 @@ void qmp_cont(Error **errp)
Error *local_err = NULL;
BlockBackend *blk;
BlockDriverState *bs;
BdrvNextIterator *it;
/* if there is a dump in background, we should wait until the dump
* finished */
@ -199,7 +200,9 @@ void qmp_cont(Error **errp)
for (blk = blk_next(NULL); blk; blk = blk_next(blk)) {
blk_iostatus_reset(blk);
}
for (bs = bdrv_next(NULL); bs; bs = bdrv_next(bs)) {
it = NULL;
while ((it = bdrv_next(it, &bs))) {
bdrv_add_key(bs, NULL, &local_err);
if (local_err) {
error_propagate(errp, local_err);