The uuid_tree_rescan_sem is used as a mutex (initialized with value 1 and with at most one active user), no reason to obscure that as a semaphore.
Signed-off-by: David Sterba <[email protected]> --- fs/btrfs/ctree.h | 6 +++++- fs/btrfs/disk-io.c | 6 +++--- fs/btrfs/super.c | 4 ++-- fs/btrfs/volumes.c | 12 ++++++------ 4 files changed, 16 insertions(+), 12 deletions(-) diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h index cab2f3607040..a643ff0fa0f0 100644 --- a/fs/btrfs/ctree.h +++ b/fs/btrfs/ctree.h @@ -1073,7 +1073,11 @@ struct btrfs_fs_info { struct percpu_counter bio_counter; wait_queue_head_t replace_wait; - struct semaphore uuid_tree_rescan_sem; + /* + * Protect updating of uuid_tree, can be used to wait for the task + * completion + */ + struct mutex uuid_tree_mutex; /* Used to reclaim the metadata space in the background. */ struct work_struct async_reclaim_work; diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c index 53c9145a56e9..8330226234f2 100644 --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -2542,10 +2542,10 @@ int open_ctree(struct super_block *sb, mutex_init(&fs_info->cleaner_mutex); mutex_init(&fs_info->volume_mutex); mutex_init(&fs_info->ro_block_group_mutex); + mutex_init(&fs_info->uuid_tree_mutex); init_rwsem(&fs_info->commit_root_sem); init_rwsem(&fs_info->cleanup_work_sem); init_rwsem(&fs_info->subvol_sem); - sema_init(&fs_info->uuid_tree_rescan_sem, 1); btrfs_init_dev_replace_locks(fs_info); btrfs_init_qgroup(fs_info); @@ -3696,9 +3696,9 @@ void close_ctree(struct btrfs_fs_info *fs_info) btrfs_qgroup_wait_for_completion(fs_info, false); /* wait for the uuid_scan task to finish */ - down(&fs_info->uuid_tree_rescan_sem); + mutex_lock(&fs_info->uuid_tree_mutex); /* avoid complains from lockdep et al., set sem back to initial state */ - up(&fs_info->uuid_tree_rescan_sem); + mutex_unlock(&fs_info->uuid_tree_mutex); /* pause restriper - we want to resume on mount */ btrfs_pause_balance(fs_info); diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c index 713f899bae81..5d0686c18bad 100644 --- a/fs/btrfs/super.c +++ b/fs/btrfs/super.c @@ -1777,9 +1777,9 @@ static int btrfs_remount(struct super_block *sb, int *flags, char *data) cancel_work_sync(&fs_info->async_reclaim_work); /* wait for the uuid_scan task to finish */ - down(&fs_info->uuid_tree_rescan_sem); + mutex_lock(&fs_info->uuid_tree_mutex); /* avoid complains from lockdep et al. */ - up(&fs_info->uuid_tree_rescan_sem); + mutex_unlock(&fs_info->uuid_tree_mutex); sb->s_flags |= MS_RDONLY; diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index 1b43f762906f..b2949232ba52 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -4202,7 +4202,7 @@ static int btrfs_uuid_scan_kthread(void *data) btrfs_warn(fs_info, "btrfs_uuid_scan_kthread failed %d", ret); else set_bit(BTRFS_FS_UPDATE_UUID_TREE_GEN, &fs_info->flags); - up(&fs_info->uuid_tree_rescan_sem); + mutex_unlock(&fs_info->uuid_tree_mutex); return 0; } @@ -4264,7 +4264,7 @@ static int btrfs_uuid_rescan_kthread(void *data) ret = btrfs_uuid_tree_iterate(fs_info, btrfs_check_uuid_tree_entry); if (ret < 0) { btrfs_warn(fs_info, "iterating uuid_tree failed %d", ret); - up(&fs_info->uuid_tree_rescan_sem); + mutex_unlock(&fs_info->uuid_tree_mutex); return ret; } return btrfs_uuid_scan_kthread(data); @@ -4301,12 +4301,12 @@ int btrfs_create_uuid_tree(struct btrfs_fs_info *fs_info) if (ret) return ret; - down(&fs_info->uuid_tree_rescan_sem); + mutex_lock(&fs_info->uuid_tree_mutex); task = kthread_run(btrfs_uuid_scan_kthread, fs_info, "btrfs-uuid"); if (IS_ERR(task)) { /* fs_info->update_uuid_tree_gen remains 0 in all error case */ btrfs_warn(fs_info, "failed to start uuid_scan task"); - up(&fs_info->uuid_tree_rescan_sem); + mutex_unlock(&fs_info->uuid_tree_mutex); return PTR_ERR(task); } @@ -4317,12 +4317,12 @@ int btrfs_check_uuid_tree(struct btrfs_fs_info *fs_info) { struct task_struct *task; - down(&fs_info->uuid_tree_rescan_sem); + mutex_lock(&fs_info->uuid_tree_mutex); task = kthread_run(btrfs_uuid_rescan_kthread, fs_info, "btrfs-uuid"); if (IS_ERR(task)) { /* fs_info->update_uuid_tree_gen remains 0 in all error case */ btrfs_warn(fs_info, "failed to start uuid_rescan task"); - up(&fs_info->uuid_tree_rescan_sem); + mutex_unlock(&fs_info->uuid_tree_mutex); return PTR_ERR(task); } -- 2.14.3 -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
