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dm btree: add ref counting ops for the leaves of top level btrees 

When using nested btrees, the top leaves of the top levels contain
block addresses for the root of the next tree down.  If we shadow a
shared leaf node the leaf values (sub tree roots) should be incremented
accordingly.

This is only an issue if there is metadata sharing in the top levels.
Which only occurs if metadata snapshots are being used (as is possible
with dm-thinp).  And could result in a block from the thinp metadata
snap being reused early, thus corrupting the thinp metadata snap.

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 2015-08-12 15:12:09 +01:00 committed by Mike Snitzer
parent 7f518ad0a2
commit b0dc3c8bc1
4 changed files with 50 additions and 16 deletions
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6
drivers/md/persistent-data/dm-btree-internal.h
View File

@ -138,4 +138,10 @@ int lower_bound(struct btree_node *n, uint64_t key);
extern struct dm_block_validator btree_node_validator;
/*
* Value type for upper levels of multi-level btrees.
*/
extern void init_le64_type(struct dm_transaction_manager *tm,
struct dm_btree_value_type *vt);
#endif /* DM_BTREE_INTERNAL_H */

16
drivers/md/persistent-data/dm-btree-remove.c
View File

@ -544,14 +544,6 @@ static int remove_raw(struct shadow_spine *s, struct dm_btree_info *info,
return r;
}
static struct dm_btree_value_type le64_type = {
.context = NULL,
.size = sizeof(__le64),
.inc = NULL,
.dec = NULL,
.equal = NULL
};
int dm_btree_remove(struct dm_btree_info *info, dm_block_t root,
uint64_t *keys, dm_block_t *new_root)
{
@ -559,12 +551,14 @@ int dm_btree_remove(struct dm_btree_info *info, dm_block_t root,
int index = 0, r = 0;
struct shadow_spine spine;
struct btree_node *n;
struct dm_btree_value_type le64_vt;
init_le64_type(info->tm, &le64_vt);
init_shadow_spine(&spine, info);
for (level = 0; level < info->levels; level++) {
r = remove_raw(&spine, info,
(level == last_level ?
&info->value_type : &le64_type),
&info->value_type : &le64_vt),
root, keys[level], (unsigned *)&index);
if (r < 0)
break;
@ -654,11 +648,13 @@ static int remove_one(struct dm_btree_info *info, dm_block_t root,
int index = 0, r = 0;
struct shadow_spine spine;
struct btree_node *n;
struct dm_btree_value_type le64_vt;
uint64_t k;
init_le64_type(info->tm, &le64_vt);
init_shadow_spine(&spine, info);
for (level = 0; level < last_level; level++) {
r = remove_raw(&spine, info, &le64_type,
r = remove_raw(&spine, info, &le64_vt,
root, keys[level], (unsigned *) &index);
if (r < 0)
goto out;

37
drivers/md/persistent-data/dm-btree-spine.c
View File

@ -249,3 +249,40 @@ int shadow_root(struct shadow_spine *s)
{
return s->root;
}
static void le64_inc(void *context, const void *value_le)
{
struct dm_transaction_manager *tm = context;
__le64 v_le;
memcpy(&v_le, value_le, sizeof(v_le));
dm_tm_inc(tm, le64_to_cpu(v_le));
}
static void le64_dec(void *context, const void *value_le)
{
struct dm_transaction_manager *tm = context;
__le64 v_le;
memcpy(&v_le, value_le, sizeof(v_le));
dm_tm_dec(tm, le64_to_cpu(v_le));
}
static int le64_equal(void *context, const void *value1_le, const void *value2_le)
{
__le64 v1_le, v2_le;
memcpy(&v1_le, value1_le, sizeof(v1_le));
memcpy(&v2_le, value2_le, sizeof(v2_le));
return v1_le == v2_le;
}
void init_le64_type(struct dm_transaction_manager *tm,
struct dm_btree_value_type *vt)
{
vt->context = tm;
vt->size = sizeof(__le64);
vt->inc = le64_inc;
vt->dec = le64_dec;
vt->equal = le64_equal;
}

7
drivers/md/persistent-data/dm-btree.c
View File

@ -667,12 +667,7 @@ static int insert(struct dm_btree_info *info, dm_block_t root,
struct btree_node *n;
struct dm_btree_value_type le64_type;
le64_type.context = NULL;
le64_type.size = sizeof(__le64);
le64_type.inc = NULL;
le64_type.dec = NULL;
le64_type.equal = NULL;
init_le64_type(info->tm, &le64_type);
init_shadow_spine(&spine, info);
for (level = 0; level < (info->levels - 1); level++) {