Commit ca664626 authored by Chris Mason's avatar Chris Mason
Browse files

Btrfs: Add efficient dirty accounting to the extent_map tree 



Signed-off-by: default avatarChris Mason <chris.mason@oracle.com>
parent 448d640b

fs/btrfs/disk-io.c

+6 −1
Original line number Diff line number Diff line
@@ -210,7 +210,7 @@ static int btree_writepages(struct address_space *mapping, 
{

	struct extent_map_tree *tree;

	tree = &BTRFS_I(mapping->host)->extent_tree;

	if (wbc->sync_mode == WB_SYNC_NONE && current_is_pdflush()) {

	if (wbc->sync_mode == WB_SYNC_NONE) {

		u64 num_dirty;

		u64 start = 0;

		unsigned long thresh = 96 * 1024 * 1024;
@@ -218,6 +218,11 @@ static int btree_writepages(struct address_space *mapping, 
		if (wbc->for_kupdate)

			return 0;



		if (current_is_pdflush()) {

			thresh = 96 * 1024 * 1024;

		} else {

			thresh = 8 * 1024 * 1024;

		}

		num_dirty = count_range_bits(tree, &start, thresh, EXTENT_DIRTY);

		if (num_dirty < thresh) {

			return 0;

fs/btrfs/extent_map.c

+29 −3
Original line number Diff line number Diff line
@@ -42,6 +42,7 @@ struct extent_page_data { 
	struct extent_map_tree *tree;

	get_extent_t *get_extent;

};



int __init extent_map_init(void)

{

	extent_map_cache = btrfs_cache_create("extent_map",
@@ -94,6 +95,7 @@ void extent_map_tree_init(struct extent_map_tree *tree, 
	tree->map.rb_node = NULL;

	tree->state.rb_node = NULL;

	tree->ops = NULL;

	tree->dirty_bytes = 0;

	rwlock_init(&tree->lock);

	spin_lock_init(&tree->lru_lock);

	tree->mapping = mapping;
@@ -414,6 +416,8 @@ static int insert_state(struct extent_map_tree *tree, 
		printk("end < start %Lu %Lu\n", end, start);

		WARN_ON(1);

	}

	if (bits & EXTENT_DIRTY)

		tree->dirty_bytes += end - start + 1;

	state->state |= bits;

	state->start = start;

	state->end = end;
@@ -476,6 +480,12 @@ static int clear_state_bit(struct extent_map_tree *tree, 
			    int delete)

{

	int ret = state->state & bits;



	if ((bits & EXTENT_DIRTY) && (state->state & EXTENT_DIRTY)) {

		u64 range = state->end - state->start + 1;

		WARN_ON(range > tree->dirty_bytes);

		tree->dirty_bytes -= range;

	}

	state->state &= ~bits;

	if (wake)

		wake_up(&state->wq);
@@ -668,6 +678,17 @@ int wait_extent_bit(struct extent_map_tree *tree, u64 start, u64 end, int bits) 
}

EXPORT_SYMBOL(wait_extent_bit);



static void set_state_bits(struct extent_map_tree *tree,

			   struct extent_state *state,

			   int bits)

{

	if ((bits & EXTENT_DIRTY) && !(state->state & EXTENT_DIRTY)) {

		u64 range = state->end - state->start + 1;

		tree->dirty_bytes += range;

	}

	state->state |= bits;

}



/*

 * set some bits on a range in the tree.  This may require allocations

 * or sleeping, so the gfp mask is used to indicate what is allowed.
@@ -727,7 +748,7 @@ int set_extent_bit(struct extent_map_tree *tree, u64 start, u64 end, int bits, 
			err = -EEXIST;

			goto out;

		}

		state->state |= bits;

		set_state_bits(tree, state, bits);

		start = state->end + 1;

		merge_state(tree, state);

		goto search_again;
@@ -762,7 +783,7 @@ int set_extent_bit(struct extent_map_tree *tree, u64 start, u64 end, int bits, 
		if (err)

			goto out;

		if (state->end <= end) {

			state->state |= bits;

			set_state_bits(tree, state, bits);

			start = state->end + 1;

			merge_state(tree, state);

		} else {
@@ -808,7 +829,7 @@ int set_extent_bit(struct extent_map_tree *tree, u64 start, u64 end, int bits, 
		err = split_state(tree, state, prealloc, end + 1);

		BUG_ON(err == -EEXIST);



		prealloc->state |= bits;

		set_state_bits(tree, prealloc, bits);

		merge_state(tree, prealloc);

		prealloc = NULL;

		goto out;
@@ -1116,6 +1137,11 @@ u64 count_range_bits(struct extent_map_tree *tree, 
	int found = 0;



	write_lock_irq(&tree->lock);

	if (bits == EXTENT_DIRTY) {

		*start = 0;

		total_bytes = tree->dirty_bytes;

		goto out;

	}

	/*

	 * this search will find all the extents that end after

	 * our range starts.

fs/btrfs/extent_map.h

+1 −0
Original line number Diff line number Diff line
@@ -40,6 +40,7 @@ struct extent_map_tree { 
	struct rb_root map;

	struct rb_root state;

	struct address_space *mapping;

	u64 dirty_bytes;

	rwlock_t lock;

	struct extent_map_ops *ops;

	spinlock_t lru_lock;