Commit 7b13b7b1 authored by Chris Mason's avatar Chris Mason
Browse files

Btrfs: Don't drop extent_map cache during releasepage on the btree inode 



The btree inode should only have a single extent_map in the cache,
it doesn't make sense to ever drop it.

Signed-off-by: default avatarChris Mason <chris.mason@oracle.com>
parent 7ae9c09d

fs/btrfs/disk-io.c

+14 −9
Original line number Diff line number Diff line
@@ -76,13 +76,12 @@ struct extent_map *btree_get_extent(struct inode *inode, struct page *page, 
	struct extent_map *em;

	int ret;



again:

	spin_lock(&em_tree->lock);

	em = lookup_extent_mapping(em_tree, start, len);

	spin_unlock(&em_tree->lock);

	if (em) {

	if (em)

		goto out;

	}



	em = alloc_extent_map(GFP_NOFS);

	if (!em) {

		em = ERR_PTR(-ENOMEM);
@@ -95,15 +94,21 @@ struct extent_map *btree_get_extent(struct inode *inode, struct page *page, 


	spin_lock(&em_tree->lock);

	ret = add_extent_mapping(em_tree, em);

	spin_unlock(&em_tree->lock);



	if (ret == -EEXIST) {

		free_extent_map(em);

		em = NULL;

		goto again;

		em = lookup_extent_mapping(em_tree, start, len);

		if (em)

			ret = 0;

		else

			ret = -EIO;

	} else if (ret) {

		em = ERR_PTR(ret);

		free_extent_map(em);

		em = NULL;

	}

	spin_unlock(&em_tree->lock);



	if (ret)

		em = ERR_PTR(ret);

out:

	return em;

}
@@ -496,7 +501,7 @@ static int btree_releasepage(struct page *page, gfp_t gfp_flags) 
	}

	tree = &BTRFS_I(page->mapping->host)->io_tree;

	map = &BTRFS_I(page->mapping->host)->extent_tree;

	ret = try_release_extent_mapping(map, tree, page, gfp_flags);

	ret = try_release_extent_state(map, tree, page, gfp_flags);

	if (ret == 1) {

		invalidate_extent_lru(tree, page_offset(page), PAGE_CACHE_SIZE);

		ClearPagePrivate(page);

fs/btrfs/extent_io.c

+27 −11
Original line number Diff line number Diff line
@@ -2463,6 +2463,31 @@ int extent_prepare_write(struct extent_io_tree *tree, 
}

EXPORT_SYMBOL(extent_prepare_write);



/*

 * a helper for releasepage, this tests for areas of the page that

 * are locked or under IO and drops the related state bits if it is safe

 * to drop the page.

 */

int try_release_extent_state(struct extent_map_tree *map,

			     struct extent_io_tree *tree, struct page *page,

			     gfp_t mask)

{

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

	u64 end = start + PAGE_CACHE_SIZE - 1;

	int ret = 1;



	if (test_range_bit(tree, start, end, EXTENT_IOBITS, 0))

		ret = 0;

	else {

		if ((mask & GFP_NOFS) == GFP_NOFS)

			mask = GFP_NOFS;

		clear_extent_bit(tree, start, end, EXTENT_UPTODATE,

				 1, 1, mask);

	}

	return ret;

}

EXPORT_SYMBOL(try_release_extent_state);



/*

 * a helper for releasepage.  As long as there are no locked extents

 * in the range corresponding to the page, both state records and extent
@@ -2475,8 +2500,7 @@ int try_release_extent_mapping(struct extent_map_tree *map, 
	struct extent_map *em;

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

	u64 end = start + PAGE_CACHE_SIZE - 1;

	u64 orig_start = start;

	int ret = 1;



	if ((mask & __GFP_WAIT) &&

	    page->mapping->host->i_size > 16 * 1024 * 1024) {

		u64 len;
@@ -2507,15 +2531,7 @@ int try_release_extent_mapping(struct extent_map_tree *map, 
			free_extent_map(em);

		}

	}

	if (test_range_bit(tree, orig_start, end, EXTENT_IOBITS, 0))

		ret = 0;

	else {

		if ((mask & GFP_NOFS) == GFP_NOFS)

			mask = GFP_NOFS;

		clear_extent_bit(tree, orig_start, end, EXTENT_UPTODATE,

				 1, 1, mask);

	}

	return ret;

	return try_release_extent_state(map, tree, page, mask);

}

EXPORT_SYMBOL(try_release_extent_mapping);

fs/btrfs/extent_io.h

+3 −0
Original line number Diff line number Diff line
@@ -110,6 +110,9 @@ void extent_io_tree_empty_lru(struct extent_io_tree *tree); 
int try_release_extent_mapping(struct extent_map_tree *map,

			       struct extent_io_tree *tree, struct page *page,

			       gfp_t mask);

int try_release_extent_state(struct extent_map_tree *map,

			     struct extent_io_tree *tree, struct page *page,

			     gfp_t mask);

int lock_extent(struct extent_io_tree *tree, u64 start, u64 end, gfp_t mask);

int unlock_extent(struct extent_io_tree *tree, u64 start, u64 end, gfp_t mask);

int extent_read_full_page(struct extent_io_tree *tree, struct page *page,