Commit 9b011adf authored by Wang Shilong's avatar Wang Shilong Committed by Chris Mason
Browse files

Btrfs: remove scrub_super_lock holding in btrfs_sync_log() 



Originally, we introduced scrub_super_lock to synchronize
tree log code with scrubbing super.

However we can replace scrub_super_lock with device_list_mutex,
because writing super will hold this mutex, this will reduce an extra
lock holding when writing supers in sync log code.

Signed-off-by: default avatarWang Shilong <wangsl.fnst@cn.fujitsu.com>
Signed-off-by: default avatarJosef Bacik <jbacik@fusionio.com>
Signed-off-by: default avatarChris Mason <chris.mason@fusionio.com>
parent 7fdf4b60

fs/btrfs/ctree.h

+0 −3
Original line number Diff line number Diff line
@@ -1586,7 +1586,6 @@ struct btrfs_fs_info { 
	atomic_t scrubs_paused;

	atomic_t scrub_cancel_req;

	wait_queue_head_t scrub_pause_wait;

	struct rw_semaphore scrub_super_lock;

	int scrub_workers_refcnt;

	struct btrfs_workers scrub_workers;

	struct btrfs_workers scrub_wr_completion_workers;
@@ -3950,9 +3949,7 @@ int btrfs_scrub_dev(struct btrfs_fs_info *fs_info, u64 devid, u64 start, 
		    u64 end, struct btrfs_scrub_progress *progress,

		    int readonly, int is_dev_replace);

void btrfs_scrub_pause(struct btrfs_root *root);

void btrfs_scrub_pause_super(struct btrfs_root *root);

void btrfs_scrub_continue(struct btrfs_root *root);

void btrfs_scrub_continue_super(struct btrfs_root *root);

int btrfs_scrub_cancel(struct btrfs_fs_info *info);

int btrfs_scrub_cancel_dev(struct btrfs_fs_info *info,

			   struct btrfs_device *dev);

fs/btrfs/disk-io.c

+0 −1
Original line number Diff line number Diff line
@@ -2250,7 +2250,6 @@ int open_ctree(struct super_block *sb, 
	atomic_set(&fs_info->scrubs_paused, 0);

	atomic_set(&fs_info->scrub_cancel_req, 0);

	init_waitqueue_head(&fs_info->scrub_pause_wait);

	init_rwsem(&fs_info->scrub_super_lock);

	fs_info->scrub_workers_refcnt = 0;

#ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY

	fs_info->check_integrity_print_mask = 0;

fs/btrfs/scrub.c

+5 −13
Original line number Diff line number Diff line
@@ -2932,13 +2932,15 @@ int btrfs_scrub_dev(struct btrfs_fs_info *fs_info, u64 devid, u64 start, 


	atomic_inc(&fs_info->scrubs_running);

	mutex_unlock(&fs_info->scrub_lock);

	mutex_unlock(&fs_info->fs_devices->device_list_mutex);



	if (!is_dev_replace) {

		down_read(&fs_info->scrub_super_lock);

		/*

		 * by holding device list mutex, we can

		 * kick off writing super in log tree sync.

		 */

		ret = scrub_supers(sctx, dev);

		up_read(&fs_info->scrub_super_lock);

	}

	mutex_unlock(&fs_info->fs_devices->device_list_mutex);



	if (!ret)

		ret = scrub_enumerate_chunks(sctx, dev, start, end,
@@ -2988,16 +2990,6 @@ void btrfs_scrub_continue(struct btrfs_root *root) 
	wake_up(&fs_info->scrub_pause_wait);

}



void btrfs_scrub_pause_super(struct btrfs_root *root)

{

	down_write(&root->fs_info->scrub_super_lock);

}



void btrfs_scrub_continue_super(struct btrfs_root *root)

{

	up_write(&root->fs_info->scrub_super_lock);

}



int btrfs_scrub_cancel(struct btrfs_fs_info *fs_info)

{

	mutex_lock(&fs_info->scrub_lock);

fs/btrfs/tree-log.c

+0 −2
Original line number Diff line number Diff line
@@ -2586,9 +2586,7 @@ int btrfs_sync_log(struct btrfs_trans_handle *trans, 
	 * the running transaction open, so a full commit can't hop

	 * in and cause problems either.

	 */

	btrfs_scrub_pause_super(root);

	ret = write_ctree_super(trans, root->fs_info->tree_root, 1);

	btrfs_scrub_continue_super(root);

	if (ret) {

		btrfs_abort_transaction(trans, root, ret);

		goto out_wake_log_root;

fs/btrfs/volumes.h

+3 −1
Original line number Diff line number Diff line
@@ -132,7 +132,9 @@ struct btrfs_fs_devices { 


	/* all of the devices in the FS, protected by a mutex

	 * so we can safely walk it to write out the supers without

	 * worrying about add/remove by the multi-device code

	 * worrying about add/remove by the multi-device code.

	 * Scrubbing super can kick off supers writing by holding

	 * this mutex lock.

	 */

	struct mutex device_list_mutex;

	struct list_head devices;

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