Commit 99be1a66 authored by David Sterba's avatar David Sterba
Browse files

btrfs: add specific helper for range bit test exists 



The existing helper test_range_bit works in two ways, checks if the whole
range contains all the bits, or stop on the first occurrence.  By adding
a specific helper for the latter case, the inner loop can be simplified
and contains fewer conditionals, making it a bit faster.

There's no caller that uses the cached state pointer so this reduces the
argument count further.

Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent 6422b4cd

fs/btrfs/defrag.c

+2 −2
Original line number Diff line number Diff line
@@ -1035,8 +1035,8 @@ static int defrag_collect_targets(struct btrfs_inode *inode, 
		 *    very likely resulting in a larger extent after writeback is

		 *    triggered (except in a case of free space fragmentation).

		 */

		if (test_range_bit(&inode->io_tree, cur, cur + range_len - 1,

				   EXTENT_DELALLOC, 0, NULL))

		if (test_range_bit_exists(&inode->io_tree, cur, cur + range_len - 1,

					  EXTENT_DELALLOC))

			goto next;



		/*

fs/btrfs/extent-io-tree.c

+31 −0
Original line number Diff line number Diff line
@@ -1639,6 +1639,37 @@ u64 count_range_bits(struct extent_io_tree *tree, 
	return total_bytes;

}



/*

 * Check if the single @bit exists in the given range.

 */

bool test_range_bit_exists(struct extent_io_tree *tree, u64 start, u64 end, u32 bit)

{

	struct extent_state *state = NULL;

	bool bitset = false;



	ASSERT(is_power_of_2(bit));



	spin_lock(&tree->lock);

	state = tree_search(tree, start);

	while (state && start <= end) {

		if (state->start > end)

			break;



		if (state->state & bit) {

			bitset = true;

			break;

		}



		/* If state->end is (u64)-1, start will overflow to 0 */

		start = state->end + 1;

		if (start > end || start == 0)

			break;

		state = next_state(state);

	}

	spin_unlock(&tree->lock);

	return bitset;

}



/*

 * Search a range in the state tree for a given mask.  If 'filled' == 1, this

 * returns 1 only if every extent in the tree has the bits set.  Otherwise, 1

fs/btrfs/extent-io-tree.h

+1 −0
Original line number Diff line number Diff line
@@ -133,6 +133,7 @@ u64 count_range_bits(struct extent_io_tree *tree, 
void free_extent_state(struct extent_state *state);

int test_range_bit(struct extent_io_tree *tree, u64 start, u64 end,

		   u32 bits, int filled, struct extent_state *cached_state);

bool test_range_bit_exists(struct extent_io_tree *tree, u64 start, u64 end, u32 bit);

int clear_record_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,

			     u32 bits, struct extent_changeset *changeset);

int __clear_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,

fs/btrfs/extent_io.c

+4 −4
Original line number Diff line number Diff line
@@ -2293,7 +2293,7 @@ static int try_release_extent_state(struct extent_io_tree *tree, 
	u64 end = start + PAGE_SIZE - 1;

	int ret = 1;



	if (test_range_bit(tree, start, end, EXTENT_LOCKED, 0, NULL)) {

	if (test_range_bit_exists(tree, start, end, EXTENT_LOCKED)) {

		ret = 0;

	} else {

		u32 clear_bits = ~(EXTENT_LOCKED | EXTENT_NODATASUM |
@@ -2352,9 +2352,9 @@ int try_release_extent_mapping(struct page *page, gfp_t mask) 
				free_extent_map(em);

				break;

			}

			if (test_range_bit(tree, em->start,

			if (test_range_bit_exists(tree, em->start,

						  extent_map_end(em) - 1,

					   EXTENT_LOCKED, 0, NULL))

						  EXTENT_LOCKED))

				goto next;

			/*

			 * If it's not in the list of modified extents, used

fs/btrfs/inode.c

+2 −4
Original line number Diff line number Diff line
@@ -2239,8 +2239,7 @@ static bool should_nocow(struct btrfs_inode *inode, u64 start, u64 end) 
{

	if (inode->flags & (BTRFS_INODE_NODATACOW | BTRFS_INODE_PREALLOC)) {

		if (inode->defrag_bytes &&

		    test_range_bit(&inode->io_tree, start, end, EXTENT_DEFRAG,

				   0, NULL))

		    test_range_bit_exists(&inode->io_tree, start, end, EXTENT_DEFRAG))

			return false;

		return true;

	}
@@ -7111,8 +7110,7 @@ noinline int can_nocow_extent(struct inode *inode, u64 offset, u64 *len, 


		range_end = round_up(offset + nocow_args.num_bytes,

				     root->fs_info->sectorsize) - 1;

		ret = test_range_bit(io_tree, offset, range_end,

				     EXTENT_DELALLOC, 0, NULL);

		ret = test_range_bit_exists(io_tree, offset, range_end, EXTENT_DELALLOC);

		if (ret) {

			ret = -EAGAIN;

			goto out;