From 086fbbbda9b743b149b0294e0feec257e2c311d5 Mon Sep 17 00:00:00 2001 From: Joe Thornber Date: Mon, 7 Dec 2015 14:48:04 +0000 Subject: dm thin metadata: make dm_thin_find_mapped_range() atomic 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 Signed-off-by: Mike Snitzer --- drivers/md/dm-thin-metadata.c | 64 +++++++++++++++++++++++++++++-------------- 1 file changed, 43 insertions(+), 21 deletions(-) (limited to 'drivers/md/dm-thin-metadata.c') diff --git a/drivers/md/dm-thin-metadata.c b/drivers/md/dm-thin-metadata.c index 7547315ff18a..f962d6453afd 100644 --- a/drivers/md/dm-thin-metadata.c +++ b/drivers/md/dm-thin-metadata.c @@ -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 @@ -1432,18 +1426,14 @@ int dm_thin_find_block(struct dm_thin_device *td, dm_block_t block, if (!r) unpack_lookup_result(td, value, 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, - dm_block_t *vblock, - struct dm_thin_lookup_result *result) +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; - __le64 value; struct dm_pool_metadata *pmd = td->pmd; - dm_block_t keys[2] = { td->id, block }; down_read(&pmd->root_lock); if (pmd->fail_io) { @@ -1451,18 +1441,32 @@ static int dm_thin_find_next_mapped_block(struct dm_thin_device *td, dm_block_t return -EINVAL; } + r = __find_block(td, block, can_issue_io, result); + + up_read(&pmd->root_lock); + return r; +} + +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) +{ + int r; + __le64 value; + struct dm_pool_metadata *pmd = td->pmd; + dm_block_t keys[2] = { td->id, block }; + 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) { -- cgit v1.2.3