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authorJoe Thornber <ejt@redhat.com>2014-10-06 15:24:55 +0100
committerMike Snitzer <snitzer@redhat.com>2014-11-10 15:25:26 -0500
commite5cfc69a513cdc9d9e753c5ce07f0cc6b496bfd3 (patch)
tree720c80d4d1cda8be53296d215bcfed7c404cf45b /drivers/md/dm-thin-metadata.c
parenta195db2d29a47c2c3a61386009bd400df18c86cf (diff)
dm thin metadata: change dm_thin_find_block to allow blocking, but not issuing, IO
This change is a prerequisite for allowing metadata to be prefetched. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Diffstat (limited to 'drivers/md/dm-thin-metadata.c')
-rw-r--r--drivers/md/dm-thin-metadata.c30
1 files changed, 13 insertions, 17 deletions
diff --git a/drivers/md/dm-thin-metadata.c b/drivers/md/dm-thin-metadata.c
index e9d33ad59df5..ee42d1c52387 100644
--- a/drivers/md/dm-thin-metadata.c
+++ b/drivers/md/dm-thin-metadata.c
@@ -1384,42 +1384,38 @@ static bool __snapshotted_since(struct dm_thin_device *td, uint32_t time)
}
int dm_thin_find_block(struct dm_thin_device *td, dm_block_t block,
- int can_block, struct dm_thin_lookup_result *result)
+ int can_issue_io, struct dm_thin_lookup_result *result)
{
- int r = -EINVAL;
- uint64_t block_time = 0;
+ int r;
__le64 value;
struct dm_pool_metadata *pmd = td->pmd;
dm_block_t keys[2] = { td->id, block };
struct dm_btree_info *info;
- if (can_block) {
- down_read(&pmd->root_lock);
- info = &pmd->info;
- } else if (down_read_trylock(&pmd->root_lock))
- info = &pmd->nb_info;
- else
- return -EWOULDBLOCK;
-
if (pmd->fail_io)
- goto out;
+ return -EINVAL;
- r = dm_btree_lookup(info, pmd->root, keys, &value);
- if (!r)
- block_time = le64_to_cpu(value);
+ down_read(&pmd->root_lock);
-out:
- up_read(&pmd->root_lock);
+ if (can_issue_io) {
+ info = &pmd->info;
+ } else
+ info = &pmd->nb_info;
+ r = dm_btree_lookup(info, pmd->root, keys, &value);
if (!r) {
+ uint64_t block_time = 0;
dm_block_t exception_block;
uint32_t exception_time;
+
+ block_time = le64_to_cpu(value);
unpack_block_time(block_time, &exception_block,
&exception_time);
result->block = exception_block;
result->shared = __snapshotted_since(td, exception_time);
}
+ up_read(&pmd->root_lock);
return r;
}