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block: Fix bdrv_next() memory leak

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The bdrv_next() users all leaked the BdrvNextIterator after completing
the iteration. Simply changing bdrv_next() to free the iterator before
returning NULL at the end of list doesn't work because some callers exit
the loop before looking at all BDSes.

This patch moves the BdrvNextIterator from the heap to the stack of
the caller and switches to a bdrv_first()/bdrv_next() interface for
initialising the iterator.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
This commit is contained in:
Kevin Wolf 2016-05-20 18:49:07 +02:00
parent 287db79df8
commit 88be7b4be4
9 changed files with 92 additions and 64 deletions
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55
block/snapshot.c
View file

@ -374,9 +374,9 @@ bool bdrv_all_can_snapshot(BlockDriverState **first_bad_bs)
{
bool ok = true;
BlockDriverState *bs;
BdrvNextIterator *it = NULL;
BdrvNextIterator it;
while (ok && (it = bdrv_next(it, &bs))) {
for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) {
AioContext *ctx = bdrv_get_aio_context(bs);
aio_context_acquire(ctx);
@ -384,8 +384,12 @@ bool bdrv_all_can_snapshot(BlockDriverState **first_bad_bs)
ok = bdrv_can_snapshot(bs);
}
aio_context_release(ctx);
if (!ok) {
goto fail;
}
}
fail:
*first_bad_bs = bs;
return ok;
}
@ -395,20 +399,27 @@ int bdrv_all_delete_snapshot(const char *name, BlockDriverState **first_bad_bs,
{
int ret = 0;
BlockDriverState *bs;
BdrvNextIterator *it = NULL;
BdrvNextIterator it;
QEMUSnapshotInfo sn1, *snapshot = &sn1;
while (ret == 0 && (it = bdrv_next(it, &bs))) {
for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) {
AioContext *ctx = bdrv_get_aio_context(bs);
aio_context_acquire(ctx);
if (bdrv_can_snapshot(bs) &&
bdrv_snapshot_find(bs, snapshot, name) >= 0) {
ret = bdrv_snapshot_delete_by_id_or_name(bs, name, err);
if (ret < 0) {
goto fail;
}
}
aio_context_release(ctx);
if (ret < 0) {
goto fail;
}
}
fail:
*first_bad_bs = bs;
return ret;
}
@ -418,9 +429,9 @@ int bdrv_all_goto_snapshot(const char *name, BlockDriverState **first_bad_bs)
{
int err = 0;
BlockDriverState *bs;
BdrvNextIterator *it = NULL;
BdrvNextIterator it;
while (err == 0 && (it = bdrv_next(it, &bs))) {
for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) {
AioContext *ctx = bdrv_get_aio_context(bs);
aio_context_acquire(ctx);
@ -428,8 +439,12 @@ int bdrv_all_goto_snapshot(const char *name, BlockDriverState **first_bad_bs)
err = bdrv_snapshot_goto(bs, name);
}
aio_context_release(ctx);
if (err < 0) {
goto fail;
}
}
fail:
*first_bad_bs = bs;
return err;
}
@ -439,9 +454,9 @@ int bdrv_all_find_snapshot(const char *name, BlockDriverState **first_bad_bs)
QEMUSnapshotInfo sn;
int err = 0;
BlockDriverState *bs;
BdrvNextIterator *it = NULL;
BdrvNextIterator it;
while (err == 0 && (it = bdrv_next(it, &bs))) {
for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) {
AioContext *ctx = bdrv_get_aio_context(bs);
aio_context_acquire(ctx);
@ -449,8 +464,12 @@ int bdrv_all_find_snapshot(const char *name, BlockDriverState **first_bad_bs)
err = bdrv_snapshot_find(bs, &sn, name);
}
aio_context_release(ctx);
if (err < 0) {
goto fail;
}
}
fail:
*first_bad_bs = bs;
return err;
}
@ -462,9 +481,9 @@ int bdrv_all_create_snapshot(QEMUSnapshotInfo *sn,
{
int err = 0;
BlockDriverState *bs;
BdrvNextIterator *it = NULL;
BdrvNextIterator it;
while (err == 0 && (it = bdrv_next(it, &bs))) {
for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) {
AioContext *ctx = bdrv_get_aio_context(bs);
aio_context_acquire(ctx);
@ -476,24 +495,32 @@ int bdrv_all_create_snapshot(QEMUSnapshotInfo *sn,
err = bdrv_snapshot_create(bs, sn);
}
aio_context_release(ctx);
if (err < 0) {
goto fail;
}
}
fail:
*first_bad_bs = bs;
return err;
}
BlockDriverState *bdrv_all_find_vmstate_bs(void)
{
bool not_found = true;
BlockDriverState *bs;
BdrvNextIterator *it = NULL;
BdrvNextIterator it;
while (not_found && (it = bdrv_next(it, &bs))) {
for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) {
AioContext *ctx = bdrv_get_aio_context(bs);
bool found;
aio_context_acquire(ctx);
not_found = !bdrv_can_snapshot(bs);
found = bdrv_can_snapshot(bs);
aio_context_release(ctx);
if (found) {
break;
}
}
return bs;
}