btrfs: change test_range_bit to scan the whole range

The semantics of test_range_bit() with filled == 0 is now in it's own
helper so test_range_bit will check the whole range unconditionally.
The detection logic is flipped and assumes success by default and
catches exceptions.

Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/extent-io-tree.c

@@ -1671,15 +1671,15 @@ bool test_range_bit_exists(struct extent_io_tree *tree, u64 start, u64 end, u32
 }
 
 /*
- * 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
- * is returned if any bit in the range is found set.
+ * Check if the whole range [@start,@end) contains the single @bit set.
  */
-int test_range_bit(struct extent_io_tree *tree, u64 start, u64 end,
-		   u32 bits, int filled, struct extent_state *cached)
+bool test_range_bit(struct extent_io_tree *tree, u64 start, u64 end, u32 bit,
+		    struct extent_state *cached)
 {
 	struct extent_state *state = NULL;
-	int bitset = 0;
+	bool bitset = true;
+
+	ASSERT(is_power_of_2(bit));
 
 	spin_lock(&tree->lock);
 	if (cached && extent_state_in_tree(cached) && cached->start <= start &&
@@ -1688,35 +1688,35 @@ int test_range_bit(struct extent_io_tree *tree, u64 start, u64 end,
 	else
 		state = tree_search(tree, start);
 	while (state && start <= end) {
-		if (filled && state->start > start) {
-			bitset = 0;
+		if (state->start > start) {
+			bitset = false;
 			break;
 		}
 
 		if (state->start > end)
 			break;
 
-		if (state->state & bits) {
-			bitset = 1;
-			if (!filled)
-				break;
-		} else if (filled) {
-			bitset = 0;
+		if ((state->state & bit) == 0) {
+			bitset = false;
 			break;
 		}
 
 		if (state->end == (u64)-1)
 			break;
 
+		/*
+		 * Last entry (if state->end is (u64)-1 and overflow happens),
+		 * or next entry starts after the range.
+		 */
 		start = state->end + 1;
-		if (start > end)
+		if (start > end || start == 0)
 			break;
 		state = next_state(state);
 	}
 
 	/* We ran out of states and were still inside of our range. */
-	if (filled && !state)
-		bitset = 0;
+	if (!state)
+		bitset = false;
 	spin_unlock(&tree->lock);
 	return bitset;
 }

fs/btrfs/extent-io-tree.h

@@ -131,8 +131,8 @@ u64 count_range_bits(struct extent_io_tree *tree,
 		     struct extent_state **cached_state);
 
 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(struct extent_io_tree *tree, u64 start, u64 end, u32 bit,
+		    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);

fs/btrfs/extent_io.c

@@ -394,7 +394,7 @@ again:
 
 	/* then test to make sure it is all still delalloc */
 	ret = test_range_bit(tree, delalloc_start, delalloc_end,
-			     EXTENT_DELALLOC, 1, cached_state);
+			     EXTENT_DELALLOC, cached_state);
 	if (!ret) {
 		unlock_extent(tree, delalloc_start, delalloc_end,
 			      &cached_state);

fs/btrfs/inode.c

@@ -3290,7 +3290,7 @@ bool btrfs_data_csum_ok(struct btrfs_bio *bbio, struct btrfs_device *dev,
 
 	if (btrfs_is_data_reloc_root(inode->root) &&
 	    test_range_bit(&inode->io_tree, file_offset, end, EXTENT_NODATASUM,
-			   1, NULL)) {
+			   NULL)) {
 		/* Skip the range without csum for data reloc inode */
 		clear_extent_bits(&inode->io_tree, file_offset, end,
 				  EXTENT_NODATASUM);

fs/btrfs/relocation.c

@@ -2631,7 +2631,7 @@ static int tree_block_processed(u64 bytenr, struct reloc_control *rc)
 	u32 blocksize = rc->extent_root->fs_info->nodesize;
 
 	if (test_range_bit(&rc->processed_blocks, bytenr,
-			   bytenr + blocksize - 1, EXTENT_DIRTY, 1, NULL))
+			   bytenr + blocksize - 1, EXTENT_DIRTY, NULL))
 		return 1;
 	return 0;
 }