Commit 03509b78 authored by Qu Wenruo's avatar Qu Wenruo Committed by David Sterba
Browse files

btrfs: update the comment for find_first_extent_bit 



The pitfall here is, if the parameter @bits has multiple bits set, we
will return the first range which just has one of the specified bits
set.

This is a little tricky if we want an exact match.  Anyway, update the
comment to make that clear.

Signed-off-by: default avatarQu Wenruo <wqu@suse.com>
Reviewed-by: default avatarDavid Sterba <dsterba@suse.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent a3efb2f0

fs/btrfs/extent_io.c

+5 −4
Original line number Diff line number Diff line
@@ -1554,11 +1554,12 @@ find_first_extent_bit_state(struct extent_io_tree *tree, 
}



/*

 * find the first offset in the io tree with 'bits' set. zero is

 * returned if we find something, and *start_ret and *end_ret are

 * set to reflect the state struct that was found.

 * Find the first offset in the io tree with one or more @bits set.

 *

 * If nothing was found, 1 is returned. If found something, return 0.

 * Note: If there are multiple bits set in @bits, any of them will match.

 *

 * Return 0 if we find something, and update @start_ret and @end_ret.

 * Return 1 if we found nothing.

 */

int find_first_extent_bit(struct extent_io_tree *tree, u64 start,

			  u64 *start_ret, u64 *end_ret, unsigned bits,