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Btrfs: Avoid fragmentation from parallel delalloc filling 

Signed-off-by: Chris Mason <chris.mason@oracle.com>
This commit is contained in:
Chris Mason 2007-11-20 10:47:25 -05:00
parent 2f4cbe6442
commit 3e9fd94ff0
1 changed files with 49 additions and 34 deletions
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83
fs/btrfs/extent_map.c
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@ -1033,11 +1033,11 @@ out:
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;
@ -1054,27 +1054,43 @@ search_again:
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 (state->state & EXTENT_LOCKED) {
DEFINE_WAIT(wait);
atomic_inc(&state->refs);
prepare_to_wait(&state->wq, &wait,
TASK_UNINTERRUPTIBLE);
write_unlock_irq(&tree->lock);
schedule();
write_lock_irq(&tree->lock);
finish_wait(&state->wq, &wait);
free_extent_state(state);
goto search_again;
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;
}
state->state |= EXTENT_LOCKED;
}
if (state->state & EXTENT_LOCKED) {
DEFINE_WAIT(wait);
atomic_inc(&state->refs);
prepare_to_wait(&state->wq, &wait,
TASK_UNINTERRUPTIBLE);
write_unlock_irq(&tree->lock);
schedule();
write_lock_irq(&tree->lock);
finish_wait(&state->wq, &wait);
free_extent_state(state);
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_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,
EXTENT_LOCKED | EXTENT_DELALLOC,
1, 0, GFP_NOFS);
}
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");
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 <= 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;
}
lock_extent(tree, start, page_end, GFP_NOFS);
end = page_end;
if (test_range_bit(tree, start, page_end, EXTENT_DELALLOC, 0)) {