diff options
| author | David Sterba <dsterba@suse.com> | 2018-04-05 01:41:06 +0200 |
|---|---|---|
| committer | David Sterba <dsterba@suse.com> | 2018-12-17 14:51:45 +0100 |
| commit | 53176dde0acd8fa49c6c2e6097283acc6241480f (patch) | |
| tree | fe42e45af2f699762556d58619b8365091ea445e /fs/btrfs/volumes.c | |
| parent | btrfs: dev-replace: swich locking to rw semaphore (diff) | |
| download | linux-53176dde0acd8fa49c6c2e6097283acc6241480f.tar.xz linux-53176dde0acd8fa49c6c2e6097283acc6241480f.zip | |
btrfs: dev-replace: remove custom read/write blocking scheme
After the rw semaphore has been added, the custom blocking using
::blocking_readers and ::read_lock_wq is redundant.
The blocking logic in __btrfs_map_block is replaced by extending the
time the semaphore is held, that has the same blocking effect on writes
as the previous custom scheme that waited until ::blocking_readers was
zero.
Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'fs/btrfs/volumes.c')
| -rw-r--r-- | fs/btrfs/volumes.c | 13 |
1 files changed, 6 insertions, 7 deletions
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index 6c806808b6a1..57174d00f74b 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -6145,10 +6145,12 @@ static int __btrfs_map_block(struct btrfs_fs_info *fs_info, btrfs_dev_replace_read_lock(dev_replace); dev_replace_is_ongoing = btrfs_dev_replace_is_ongoing(dev_replace); + /* + * Hold the semaphore for read during the whole operation, write is + * requested at commit time but must wait. + */ if (!dev_replace_is_ongoing) btrfs_dev_replace_read_unlock(dev_replace); - else - btrfs_dev_replace_set_lock_blocking(dev_replace); if (dev_replace_is_ongoing && mirror_num == map->num_stripes + 1 && !need_full_stripe(op) && dev_replace->tgtdev != NULL) { @@ -6343,11 +6345,8 @@ static int __btrfs_map_block(struct btrfs_fs_info *fs_info, } out: if (dev_replace_is_ongoing) { - ASSERT(atomic_read(&dev_replace->blocking_readers) > 0); - btrfs_dev_replace_read_lock(dev_replace); - /* Barrier implied by atomic_dec_and_test */ - if (atomic_dec_and_test(&dev_replace->blocking_readers)) - cond_wake_up_nomb(&dev_replace->read_lock_wq); + lockdep_assert_held(&dev_replace->rwsem); + /* Unlock and let waiting writers proceed */ btrfs_dev_replace_read_unlock(dev_replace); } free_extent_map(em); |