Commit cb7ab021 authored by Wang Shilong's avatar Wang Shilong Committed by Chris Mason
Browse files

Btrfs: wrap repeated code into scrub_blocked_if_needed() 



Just wrap same code into one function scrub_blocked_if_needed().

This make a change that we will move waiting (@workers_pending = 0)
before we can wake up commiting transaction(atomic_inc(@scrub_paused)),
we must take carefully to not deadlock here.

Thread 1			Thread 2
				|->btrfs_commit_transaction()
					|->set trans type(COMMIT_DOING)
					|->btrfs_scrub_paused()(blocked)
|->join_transaction(blocked)

Move btrfs_scrub_paused() before setting trans type which means we can
still join a transaction when commiting_transaction is blocked.

Signed-off-by: default avatarWang Shilong <wangsl.fnst@cn.fujitsu.com>
Suggested-by: default avatarMiao Xie <miaox@cn.fujitsu.com>
Signed-off-by: default avatarJosef Bacik <jbacik@fb.com>
Signed-off-by: default avatarChris Mason <clm@fb.com>
parent 3cb0929a

fs/btrfs/scrub.c

+17 −26
Original line number Diff line number Diff line
@@ -256,6 +256,7 @@ static int copy_nocow_pages_for_inode(u64 inum, u64 offset, u64 root, 
static int copy_nocow_pages(struct scrub_ctx *sctx, u64 logical, u64 len,

			    int mirror_num, u64 physical_for_dev_replace);

static void copy_nocow_pages_worker(struct btrfs_work *work);

static void __scrub_blocked_if_needed(struct btrfs_fs_info *fs_info);

static void scrub_blocked_if_needed(struct btrfs_fs_info *fs_info);
@@ -270,7 +271,7 @@ static void scrub_pending_bio_dec(struct scrub_ctx *sctx) 
	wake_up(&sctx->list_wait);

}



static void scrub_blocked_if_needed(struct btrfs_fs_info *fs_info)

static void __scrub_blocked_if_needed(struct btrfs_fs_info *fs_info)

{

	while (atomic_read(&fs_info->scrub_pause_req)) {

		mutex_unlock(&fs_info->scrub_lock);
@@ -280,6 +281,19 @@ static void scrub_blocked_if_needed(struct btrfs_fs_info *fs_info) 
	}

}



static void scrub_blocked_if_needed(struct btrfs_fs_info *fs_info)

{

	atomic_inc(&fs_info->scrubs_paused);

	wake_up(&fs_info->scrub_pause_wait);



	mutex_lock(&fs_info->scrub_lock);

	__scrub_blocked_if_needed(fs_info);

	atomic_dec(&fs_info->scrubs_paused);

	mutex_unlock(&fs_info->scrub_lock);



	wake_up(&fs_info->scrub_pause_wait);

}



/*

 * used for workers that require transaction commits (i.e., for the

 * NOCOW case)
@@ -2295,8 +2309,7 @@ static noinline_for_stack int scrub_stripe(struct scrub_ctx *sctx, 


	wait_event(sctx->list_wait,

		   atomic_read(&sctx->bios_in_flight) == 0);

	atomic_inc(&fs_info->scrubs_paused);

	wake_up(&fs_info->scrub_pause_wait);

	scrub_blocked_if_needed(fs_info);



	/* FIXME it might be better to start readahead at commit root */

	key_start.objectid = logical;
@@ -2320,12 +2333,6 @@ static noinline_for_stack int scrub_stripe(struct scrub_ctx *sctx, 
	if (!IS_ERR(reada2))

		btrfs_reada_wait(reada2);



	mutex_lock(&fs_info->scrub_lock);

	scrub_blocked_if_needed(fs_info);

	atomic_dec(&fs_info->scrubs_paused);

	mutex_unlock(&fs_info->scrub_lock);



	wake_up(&fs_info->scrub_pause_wait);



	/*

	 * collect all data csums for the stripe to avoid seeking during
@@ -2362,15 +2369,7 @@ static noinline_for_stack int scrub_stripe(struct scrub_ctx *sctx, 
			wait_event(sctx->list_wait,

				   atomic_read(&sctx->bios_in_flight) == 0);

			atomic_set(&sctx->wr_ctx.flush_all_writes, 0);

			atomic_inc(&fs_info->scrubs_paused);

			wake_up(&fs_info->scrub_pause_wait);



			mutex_lock(&fs_info->scrub_lock);

			scrub_blocked_if_needed(fs_info);

			atomic_dec(&fs_info->scrubs_paused);

			mutex_unlock(&fs_info->scrub_lock);



			wake_up(&fs_info->scrub_pause_wait);

		}



		key.objectid = logical;
@@ -2685,17 +2684,9 @@ int scrub_enumerate_chunks(struct scrub_ctx *sctx, 
		wait_event(sctx->list_wait,

			   atomic_read(&sctx->bios_in_flight) == 0);

		atomic_set(&sctx->wr_ctx.flush_all_writes, 0);

		atomic_inc(&fs_info->scrubs_paused);

		wake_up(&fs_info->scrub_pause_wait);

		wait_event(sctx->list_wait,

			   atomic_read(&sctx->workers_pending) == 0);



		mutex_lock(&fs_info->scrub_lock);

		scrub_blocked_if_needed(fs_info);

		atomic_dec(&fs_info->scrubs_paused);

		mutex_unlock(&fs_info->scrub_lock);



		wake_up(&fs_info->scrub_pause_wait);



		btrfs_put_block_group(cache);

		if (ret)
@@ -2912,7 +2903,7 @@ int btrfs_scrub_dev(struct btrfs_fs_info *fs_info, u64 devid, u64 start, 
	 * checking @scrub_pause_req here, we can avoid

	 * race between committing transaction and scrubbing.

	 */

	scrub_blocked_if_needed(fs_info);

	__scrub_blocked_if_needed(fs_info);

	atomic_inc(&fs_info->scrubs_running);

	mutex_unlock(&fs_info->scrub_lock);

fs/btrfs/transaction.c

+2 −1
Original line number Diff line number Diff line
@@ -1748,6 +1748,8 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans, 
		goto cleanup_transaction;



	btrfs_wait_delalloc_flush(root->fs_info);



	btrfs_scrub_pause(root);

	/*

	 * Ok now we need to make sure to block out any other joins while we

	 * commit the transaction.  We could have started a join before setting
@@ -1812,7 +1814,6 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans, 


	WARN_ON(cur_trans != trans->transaction);



	btrfs_scrub_pause(root);

	/* btrfs_commit_tree_roots is responsible for getting the

	 * various roots consistent with each other.  Every pointer

	 * in the tree of tree roots has to point to the most up to date

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