This is a note to let you know that I've just added the patch titled
dm thin metadata: use pool locking at end of dm_pool_metadata_close
to the 5.5-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
dm-thin-metadata-use-pool-locking-at-end-of-dm_pool_metadata_close.patch
and it can be found in the queue-5.5 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 44d8ebf436399a40fcd10dd31b29d37823d62fcc Mon Sep 17 00:00:00 2001
From: Mike Snitzer <snitzer@xxxxxxxxxx>
Date: Mon, 13 Jan 2020 11:18:51 -0500
Subject: dm thin metadata: use pool locking at end of dm_pool_metadata_close
From: Mike Snitzer <snitzer@xxxxxxxxxx>
commit 44d8ebf436399a40fcd10dd31b29d37823d62fcc upstream.
Ensure that the pool is locked during calls to __commit_transaction and
__destroy_persistent_data_objects. Just being consistent with locking,
but reality is dm_pool_metadata_close is called once pool is being
destroyed so access to pool shouldn't be contended.
Also, use pmd_write_lock_in_core rather than __pmd_write_lock in
dm_pool_commit_metadata and rename __pmd_write_lock to
pmd_write_lock_in_core -- there was no need for the alias.
In addition, verify that the pool is locked in __commit_transaction().
Fixes: 873f258becca ("dm thin metadata: do not write metadata if no changes occurred")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Mike Snitzer <snitzer@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/md/dm-thin-metadata.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)
--- a/drivers/md/dm-thin-metadata.c
+++ b/drivers/md/dm-thin-metadata.c
@@ -387,16 +387,15 @@ static int subtree_equal(void *context,
* Variant that is used for in-core only changes or code that
* shouldn't put the pool in service on its own (e.g. commit).
*/
-static inline void __pmd_write_lock(struct dm_pool_metadata *pmd)
+static inline void pmd_write_lock_in_core(struct dm_pool_metadata *pmd)
__acquires(pmd->root_lock)
{
down_write(&pmd->root_lock);
}
-#define pmd_write_lock_in_core(pmd) __pmd_write_lock((pmd))
static inline void pmd_write_lock(struct dm_pool_metadata *pmd)
{
- __pmd_write_lock(pmd);
+ pmd_write_lock_in_core(pmd);
if (unlikely(!pmd->in_service))
pmd->in_service = true;
}
@@ -831,6 +830,7 @@ static int __commit_transaction(struct d
* We need to know if the thin_disk_superblock exceeds a 512-byte sector.
*/
BUILD_BUG_ON(sizeof(struct thin_disk_superblock) > 512);
+ BUG_ON(!rwsem_is_locked(&pmd->root_lock));
if (unlikely(!pmd->in_service))
return 0;
@@ -953,6 +953,7 @@ int dm_pool_metadata_close(struct dm_poo
return -EBUSY;
}
+ pmd_write_lock_in_core(pmd);
if (!dm_bm_is_read_only(pmd->bm) && !pmd->fail_io) {
r = __commit_transaction(pmd);
if (r < 0)
@@ -961,6 +962,7 @@ int dm_pool_metadata_close(struct dm_poo
}
if (!pmd->fail_io)
__destroy_persistent_data_objects(pmd);
+ pmd_write_unlock(pmd);
kfree(pmd);
return 0;
@@ -1841,7 +1843,7 @@ int dm_pool_commit_metadata(struct dm_po
* Care is taken to not have commit be what
* triggers putting the thin-pool in-service.
*/
- __pmd_write_lock(pmd);
+ pmd_write_lock_in_core(pmd);
if (pmd->fail_io)
goto out;
Patches currently in stable-queue which might be from snitzer@xxxxxxxxxx are
queue-5.5/dm-crypt-fix-benbi-iv-constructor-crash-if-used-in-authenticated-mode.patch
queue-5.5/dm-fix-potential-for-q-make_request_fn-null-pointer.patch
queue-5.5/dm-crypt-fix-gfp-flags-passed-to-skcipher_request_alloc.patch
queue-5.5/dm-writecache-fix-incorrect-flush-sequence-when-doing-ssd-mode-commit.patch
queue-5.5/dm-thin-metadata-use-pool-locking-at-end-of-dm_pool_metadata_close.patch
queue-5.5/dm-thin-fix-use-after-free-in-metadata_pre_commit_callback.patch
queue-5.5/dm-zoned-support-zone-sizes-smaller-than-128mib.patch
queue-5.5/dm-space-map-common-fix-to-ensure-new-block-isn-t-already-in-use.patch
