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dm thin metadata: fix bug in dm_thin_remove_range()

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dm_btree_remove_leaves() only unmaps a contiguous region so we need a
loop, in __remove_range(), to handle ranges that contain multiple
regions.

A new btree function, dm_btree_lookup_next(), is introduced which is
more efficiently able to skip over regions of the thin device which
aren't mapped.  __remove_range() uses dm_btree_lookup_next() for each
iteration of __remove_range()'s loop.

Also, improve description of dm_btree_remove_leaves().

Fixes: 6550f075 ("dm thin metadata: add dm_thin_remove_range()")
Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org # 4.1+
This commit is contained in:
Joe Thornber
2015-12-02 12:24:39 +00:00
committed by Mike Snitzer
parent 30ce6e1cc5
commit 993ceab919
3 changed files with 115 additions and 8 deletions
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81
drivers/md/persistent-data/dm-btree.c
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@@ -63,6 +63,11 @@ int lower_bound(struct btree_node *n, uint64_t key)
return bsearch(n, key, 0);
}
static int upper_bound(struct btree_node *n, uint64_t key)
{
return bsearch(n, key, 1);
}
void inc_children(struct dm_transaction_manager *tm, struct btree_node *n,
struct dm_btree_value_type *vt)
{
@@ -392,6 +397,82 @@ int dm_btree_lookup(struct dm_btree_info *info, dm_block_t root,
}
EXPORT_SYMBOL_GPL(dm_btree_lookup);
static int dm_btree_lookup_next_single(struct dm_btree_info *info, dm_block_t root,
uint64_t key, uint64_t *rkey, void *value_le)
{
int r, i;
uint32_t flags, nr_entries;
struct dm_block *node;
struct btree_node *n;
r = bn_read_lock(info, root, &node);
if (r)
return r;
n = dm_block_data(node);
flags = le32_to_cpu(n->header.flags);
nr_entries = le32_to_cpu(n->header.nr_entries);
if (flags & INTERNAL_NODE) {
i = lower_bound(n, key);
if (i < 0 || i >= nr_entries) {
r = -ENODATA;
goto out;
}
r = dm_btree_lookup_next_single(info, value64(n, i), key, rkey, value_le);
if (r == -ENODATA && i < (nr_entries - 1)) {
i++;
r = dm_btree_lookup_next_single(info, value64(n, i), key, rkey, value_le);
}
} else {
i = upper_bound(n, key);
if (i < 0 || i >= nr_entries) {
r = -ENODATA;
goto out;
}
*rkey = le64_to_cpu(n->keys[i]);
memcpy(value_le, value_ptr(n, i), info->value_type.size);
}
out:
dm_tm_unlock(info->tm, node);
return r;
}
int dm_btree_lookup_next(struct dm_btree_info *info, dm_block_t root,
uint64_t *keys, uint64_t *rkey, void *value_le)
{
unsigned level;
int r = -ENODATA;
__le64 internal_value_le;
struct ro_spine spine;
init_ro_spine(&spine, info);
for (level = 0; level < info->levels - 1u; level++) {
r = btree_lookup_raw(&spine, root, keys[level],
lower_bound, rkey,
&internal_value_le, sizeof(uint64_t));
if (r)
goto out;
if (*rkey != keys[level]) {
r = -ENODATA;
goto out;
}
root = le64_to_cpu(internal_value_le);
}
r = dm_btree_lookup_next_single(info, root, keys[level], rkey, value_le);
out:
exit_ro_spine(&spine);
return r;
}
EXPORT_SYMBOL_GPL(dm_btree_lookup_next);
/*
* Splits a node by creating a sibling node and shifting half the nodes
* contents across. Assumes there is a parent node, and it has room for