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dm thin metadata: make dm_thin_find_mapped_range() atomic

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Refactor dm_thin_find_mapped_range() so that it takes the read lock on
the metadata's lock; rather than relying on finer grained locking that
is pushed down inside dm_thin_find_next_mapped_block() and
dm_thin_find_block().

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
This commit is contained in:
Joe Thornber 2015-12-07 14:48:04 +00:00 committed by Mike Snitzer
parent 3d5f67332a
commit 086fbbbda9
1 changed files with 44 additions and 22 deletions
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66
drivers/md/dm-thin-metadata.c
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@ -1408,8 +1408,8 @@ static void unpack_lookup_result(struct dm_thin_device *td, __le64 value,
result->shared = __snapshotted_since(td, exception_time);
}
int dm_thin_find_block(struct dm_thin_device *td, dm_block_t block,
int can_issue_io, struct dm_thin_lookup_result *result)
static int __find_block(struct dm_thin_device *td, dm_block_t block,
int can_issue_io, struct dm_thin_lookup_result *result)
{
int r;
__le64 value;
@ -1417,12 +1417,6 @@ int dm_thin_find_block(struct dm_thin_device *td, dm_block_t block,
dm_block_t keys[2] = { td->id, block };
struct dm_btree_info *info;
down_read(&pmd->root_lock);
if (pmd->fail_io) {
up_read(&pmd->root_lock);
return -EINVAL;
}
if (can_issue_io) {
info = &pmd->info;
} else
@ -1432,11 +1426,28 @@ int dm_thin_find_block(struct dm_thin_device *td, dm_block_t block,
if (!r)
unpack_lookup_result(td, value, result);
return r;
}
int dm_thin_find_block(struct dm_thin_device *td, dm_block_t block,
int can_issue_io, struct dm_thin_lookup_result *result)
{
int r;
struct dm_pool_metadata *pmd = td->pmd;
down_read(&pmd->root_lock);
if (pmd->fail_io) {
up_read(&pmd->root_lock);
return -EINVAL;
}
r = __find_block(td, block, can_issue_io, result);
up_read(&pmd->root_lock);
return r;
}
static int dm_thin_find_next_mapped_block(struct dm_thin_device *td, dm_block_t block,
static int __find_next_mapped_block(struct dm_thin_device *td, dm_block_t block,
dm_block_t *vblock,
struct dm_thin_lookup_result *result)
{
@ -1445,24 +1456,17 @@ static int dm_thin_find_next_mapped_block(struct dm_thin_device *td, dm_block_t
struct dm_pool_metadata *pmd = td->pmd;
dm_block_t keys[2] = { td->id, block };
down_read(&pmd->root_lock);
if (pmd->fail_io) {
up_read(&pmd->root_lock);
return -EINVAL;
}
r = dm_btree_lookup_next(&pmd->info, pmd->root, keys, vblock, &value);
if (!r)
unpack_lookup_result(td, value, result);
up_read(&pmd->root_lock);
return r;
}
int dm_thin_find_mapped_range(struct dm_thin_device *td,
dm_block_t begin, dm_block_t end,
dm_block_t *thin_begin, dm_block_t *thin_end,
dm_block_t *pool_begin, bool *maybe_shared)
static int __find_mapped_range(struct dm_thin_device *td,
dm_block_t begin, dm_block_t end,
dm_block_t *thin_begin, dm_block_t *thin_end,
dm_block_t *pool_begin, bool *maybe_shared)
{
int r;
dm_block_t pool_end;
@ -1471,7 +1475,7 @@ int dm_thin_find_mapped_range(struct dm_thin_device *td,
if (end < begin)
return -ENODATA;
r = dm_thin_find_next_mapped_block(td, begin, &begin, &lookup);
r = __find_next_mapped_block(td, begin, &begin, &lookup);
if (r)
return r;
@ -1485,7 +1489,7 @@ int dm_thin_find_mapped_range(struct dm_thin_device *td,
begin++;
pool_end = *pool_begin + 1;
while (begin != end) {
r = dm_thin_find_block(td, begin, true, &lookup);
r = __find_block(td, begin, true, &lookup);
if (r) {
if (r == -ENODATA)
break;
@ -1505,6 +1509,24 @@ int dm_thin_find_mapped_range(struct dm_thin_device *td,
return 0;
}
int dm_thin_find_mapped_range(struct dm_thin_device *td,
dm_block_t begin, dm_block_t end,
dm_block_t *thin_begin, dm_block_t *thin_end,
dm_block_t *pool_begin, bool *maybe_shared)
{
int r = -EINVAL;
struct dm_pool_metadata *pmd = td->pmd;
down_read(&pmd->root_lock);
if (!pmd->fail_io) {
r = __find_mapped_range(td, begin, end, thin_begin, thin_end,
pool_begin, maybe_shared);
}
up_read(&pmd->root_lock);
return r;
}
static int __insert(struct dm_thin_device *td, dm_block_t block,
dm_block_t data_block)
{