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dm space map metadata: fix ref counting bug when bootstrapping a new space map

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When applying block operations (BOPs) do not remove them from the
uncommitted BOP ring-buffer until after they've been applied -- in case
we recurse.

Also, perform BOP_INC operation, in dm_sm_metadata_create() and
sm_metadata_extend(), in terms of the uncommitted BOP ring-buffer rather
than using direct calls to sm_ll_inc().

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org
This commit is contained in:
Joe Thornber 2015-12-09 16:38:12 +00:00 committed by Mike Snitzer
parent 49e99fc717
commit 50dd842ad8
1 changed files with 22 additions and 10 deletions
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32
drivers/md/persistent-data/dm-space-map-metadata.c
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@ -136,7 +136,7 @@ static int brb_push(struct bop_ring_buffer *brb,
return 0;
}
static int brb_pop(struct bop_ring_buffer *brb, struct block_op *result)
static int brb_peek(struct bop_ring_buffer *brb, struct block_op *result)
{
struct block_op *bop;
@ -147,6 +147,17 @@ static int brb_pop(struct bop_ring_buffer *brb, struct block_op *result)
result->type = bop->type;
result->block = bop->block;
return 0;
}
static int brb_pop(struct bop_ring_buffer *brb)
{
struct block_op *bop;
if (brb_empty(brb))
return -ENODATA;
bop = brb->bops + brb->begin;
brb->begin = brb_next(brb, brb->begin);
return 0;
@ -211,7 +222,7 @@ static int apply_bops(struct sm_metadata *smm)
while (!brb_empty(&smm->uncommitted)) {
struct block_op bop;
r = brb_pop(&smm->uncommitted, &bop);
r = brb_peek(&smm->uncommitted, &bop);
if (r) {
DMERR("bug in bop ring buffer");
break;
@ -220,6 +231,8 @@ static int apply_bops(struct sm_metadata *smm)
r = commit_bop(smm, &bop);
if (r)
break;
brb_pop(&smm->uncommitted);
}
return r;
@ -683,7 +696,6 @@ static struct dm_space_map bootstrap_ops = {
static int sm_metadata_extend(struct dm_space_map *sm, dm_block_t extra_blocks)
{
int r, i;
enum allocation_event ev;
struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
dm_block_t old_len = smm->ll.nr_blocks;
@ -705,11 +717,12 @@ static int sm_metadata_extend(struct dm_space_map *sm, dm_block_t extra_blocks)
* allocate any new blocks.
*/
do {
for (i = old_len; !r && i < smm->begin; i++) {
r = sm_ll_inc(&smm->ll, i, &ev);
if (r)
goto out;
}
for (i = old_len; !r && i < smm->begin; i++)
r = add_bop(smm, BOP_INC, i);
if (r)
goto out;
old_len = smm->begin;
r = apply_bops(smm);
@ -754,7 +767,6 @@ int dm_sm_metadata_create(struct dm_space_map *sm,
{
int r;
dm_block_t i;
enum allocation_event ev;
struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
smm->begin = superblock + 1;
@ -782,7 +794,7 @@ int dm_sm_metadata_create(struct dm_space_map *sm,
* allocated blocks that they were built from.
*/
for (i = superblock; !r && i < smm->begin; i++)
r = sm_ll_inc(&smm->ll, i, &ev);
r = add_bop(smm, BOP_INC, i);
if (r)
return r;