btrfs: remove btrfs_dev_replace::read_locks

This member seems to be copied from the extent_buffer locking scheme and
is at least used to assert that the read lock/unlock is properly nested.
In some way. While the _inc/_dec are called inside the read lock
section, the asserts are both inside and outside, so the ordering is not
guaranteed and we can see read/inc/dec ordered in any way
(theoretically).

A missing call of btrfs_dev_replace_clear_lock_blocking could cause
unexpected read_locks count, so this at least looks like a valid
assertion, but this will become unnecessary with later updates.

Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>

1 files changed, 0 insertions, 5 deletions

diff --git a/fs/btrfs/dev-replace.c b/fs/btrfs/dev-replace.c
index ff01740158aa..702fe6a65075 100644
--- a/fs/btrfs/dev-replace.c
+++ b/fs/btrfs/dev-replace.c
@@ -964,13 +964,10 @@ int btrfs_dev_replace_is_ongoing(struct btrfs_dev_replace *dev_replace)
 void btrfs_dev_replace_read_lock(struct btrfs_dev_replace *dev_replace)
 {
         read_lock(&dev_replace->lock);
-        atomic_inc(&dev_replace->read_locks);
 }
 
 void btrfs_dev_replace_read_unlock(struct btrfs_dev_replace *dev_replace)
 {
-        ASSERT(atomic_read(&dev_replace->read_locks) > 0);
-        atomic_dec(&dev_replace->read_locks);
         read_unlock(&dev_replace->lock);
 }
 
@@ -997,7 +994,6 @@ void btrfs_dev_replace_set_lock_blocking(
                                         struct btrfs_dev_replace *dev_replace)
 {
         /* only set blocking for read lock */
-        ASSERT(atomic_read(&dev_replace->read_locks) > 0);
         atomic_inc(&dev_replace->blocking_readers);
         read_unlock(&dev_replace->lock);
 }
@@ -1007,7 +1003,6 @@ void btrfs_dev_replace_clear_lock_blocking(
                                         struct btrfs_dev_replace *dev_replace)
 {
         /* only set blocking for read lock */
-        ASSERT(atomic_read(&dev_replace->read_locks) > 0);
         ASSERT(atomic_read(&dev_replace->blocking_readers) > 0);
         read_lock(&dev_replace->lock);
         /* Barrier implied by atomic_dec_and_test */