Commit 3e9fd94f authored by Chris Mason's avatar Chris Mason
Browse files

Btrfs: Avoid fragmentation from parallel delalloc filling 



Signed-off-by: default avatarChris Mason <chris.mason@oracle.com>
parent 2f4cbe64

fs/btrfs/extent_map.c

+49 −34
Original line number Diff line number Diff line
@@ -1033,11 +1033,11 @@ int find_first_extent_bit(struct extent_map_tree *tree, u64 start, 
EXPORT_SYMBOL(find_first_extent_bit);



u64 find_lock_delalloc_range(struct extent_map_tree *tree,

			     u64 start, u64 lock_start, u64 *end, u64 max_bytes)

			     u64 *start, u64 *end, u64 max_bytes)

{

	struct rb_node *node;

	struct extent_state *state;

	u64 cur_start = start;

	u64 cur_start = *start;

	u64 found = 0;

	u64 total_bytes = 0;
@@ -1054,13 +1054,28 @@ u64 find_lock_delalloc_range(struct extent_map_tree *tree, 


	while(1) {

		state = rb_entry(node, struct extent_state, rb_node);

		if (state->start != cur_start) {

		if (found && state->start != cur_start) {

			goto out;

		}

		if (!(state->state & EXTENT_DELALLOC)) {

			goto out;

		}

		if (state->start >= lock_start) {

		if (!found) {

			struct extent_state *prev_state;

			struct rb_node *prev_node = node;

			while(1) {

				prev_node = rb_prev(prev_node);

				if (!prev_node)

					break;

				prev_state = rb_entry(prev_node,

						      struct extent_state,

						      rb_node);

				if (!(prev_state->state & EXTENT_DELALLOC))

					break;

				state = prev_state;

				node = prev_node;

			}

		}

		if (state->state & EXTENT_LOCKED) {

			DEFINE_WAIT(wait);

			atomic_inc(&state->refs);
@@ -1074,7 +1089,8 @@ u64 find_lock_delalloc_range(struct extent_map_tree *tree, 
			goto search_again;

		}

		state->state |= EXTENT_LOCKED;

		}

		if (!found)

			*start = state->start;

		found++;

		*end = state->end;

		cur_start = state->end + 1;
@@ -1695,6 +1711,7 @@ static int __extent_writepage(struct page *page, struct writeback_control *wbc, 
	struct extent_page_data *epd = data;

	struct extent_map_tree *tree = epd->tree;

	u64 start = (u64)page->index << PAGE_CACHE_SHIFT;

	u64 delalloc_start;

	u64 page_end = start + PAGE_CACHE_SIZE - 1;

	u64 end;

	u64 cur = start;
@@ -1729,25 +1746,23 @@ static int __extent_writepage(struct page *page, struct writeback_control *wbc, 


	set_page_extent_mapped(page);



	lock_extent(tree, start, page_end, GFP_NOFS);

	nr_delalloc = find_lock_delalloc_range(tree, start, page_end + 1,

	delalloc_start = start;

	delalloc_end = 0;

	while(delalloc_end < page_end) {

		nr_delalloc = find_lock_delalloc_range(tree, &delalloc_start,

						       &delalloc_end,

						       128 * 1024 * 1024);

	if (nr_delalloc) {

		tree->ops->fill_delalloc(inode, start, delalloc_end);

		if (delalloc_end >= page_end + 1) {

			clear_extent_bit(tree, page_end + 1, delalloc_end,

		if (nr_delalloc <= 0)

			break;

		tree->ops->fill_delalloc(inode, delalloc_start,

					 delalloc_end);

		clear_extent_bit(tree, delalloc_start,

				 delalloc_end,

				 EXTENT_LOCKED | EXTENT_DELALLOC,

				 1, 0, GFP_NOFS);

		delalloc_start = delalloc_end + 1;

	}

		clear_extent_bit(tree, start, page_end, EXTENT_DELALLOC,

				 0, 0, GFP_NOFS);

		if (test_range_bit(tree, start, page_end, EXTENT_DELALLOC, 0)) {

			printk("found delalloc bits after clear extent_bit\n");

		}

	} else if (test_range_bit(tree, start, page_end, EXTENT_DELALLOC, 0)) {

		printk("found delalloc bits after find_delalloc_range returns 0\n");

	}

	lock_extent(tree, start, page_end, GFP_NOFS);



	end = page_end;

	if (test_range_bit(tree, start, page_end, EXTENT_DELALLOC, 0)) {