diff options
Diffstat (limited to 'fs/ext2/balloc.c')
| -rw-r--r-- | fs/ext2/balloc.c | 101 |
1 files changed, 46 insertions, 55 deletions
diff --git a/fs/ext2/balloc.c b/fs/ext2/balloc.c index 2f48d25170f7..27377a0faa6f 100644 --- a/fs/ext2/balloc.c +++ b/fs/ext2/balloc.c @@ -718,36 +718,34 @@ fail_access: } /** - * find_next_reservable_window(): - * find a reservable space within the given range. - * It does not allocate the reservation window for now: - * alloc_new_reservation() will do the work later. + * find_next_reservable_window - Find a reservable space within the given range. + * @search_head: The list to search. + * @my_rsv: The reservation we're currently using. + * @sb: The super block. + * @start_block: The first block we consider to start the real search from + * @last_block: The maximum block number that our goal reservable space + * could start from. * - * @search_head: the head of the searching list; - * This is not necessarily the list head of the whole filesystem + * It does not allocate the reservation window: alloc_new_reservation() + * will do the work later. * - * We have both head and start_block to assist the search - * for the reservable space. The list starts from head, - * but we will shift to the place where start_block is, - * then start from there, when looking for a reservable space. + * We search the given range, rather than the whole reservation double + * linked list, (start_block, last_block) to find a free region that is + * of my size and has not been reserved. * - * @sb: the super block. + * @search_head is not necessarily the list head of the whole filesystem. + * We have both head and @start_block to assist the search for the + * reservable space. The list starts from head, but we will shift to + * the place where start_block is, then start from there, when looking + * for a reservable space. * - * @start_block: the first block we consider to start the real search from - * - * @last_block: - * the maximum block number that our goal reservable space - * could start from. This is normally the last block in this - * group. The search will end when we found the start of next - * possible reservable space is out of this boundary. - * This could handle the cross boundary reservation window - * request. - * - * basically we search from the given range, rather than the whole - * reservation double linked list, (start_block, last_block) - * to find a free region that is of my size and has not - * been reserved. + * @last_block is normally the last block in this group. The search will end + * when we found the start of next possible reservable space is out + * of this boundary. This could handle the cross boundary reservation + * window request. * + * Return: -1 if we could not find a range of sufficient size. If we could, + * return 0 and fill in @my_rsv with the range information. */ static int find_next_reservable_window( struct ext2_reserve_window_node *search_head, @@ -835,41 +833,34 @@ static int find_next_reservable_window( } /** - * alloc_new_reservation()--allocate a new reservation window - * - * To make a new reservation, we search part of the filesystem - * reservation list (the list that inside the group). We try to - * allocate a new reservation window near the allocation goal, - * or the beginning of the group, if there is no goal. - * - * We first find a reservable space after the goal, then from - * there, we check the bitmap for the first free block after - * it. If there is no free block until the end of group, then the - * whole group is full, we failed. Otherwise, check if the free - * block is inside the expected reservable space, if so, we - * succeed. - * If the first free block is outside the reservable space, then - * start from the first free block, we search for next available - * space, and go on. - * - * on succeed, a new reservation will be found and inserted into the list - * It contains at least one free block, and it does not overlap with other - * reservation windows. + * alloc_new_reservation - Allocate a new reservation window. + * @my_rsv: The reservation we're currently using. + * @grp_goal: The goal block relative to the start of the group. + * @sb: The super block. + * @group: The group we are trying to allocate in. + * @bitmap_bh: The block group block bitmap. * - * failed: we failed to find a reservation window in this group + * To make a new reservation, we search part of the filesystem reservation + * list (the list inside the group). We try to allocate a new + * reservation window near @grp_goal, or the beginning of the + * group, if @grp_goal is negative. * - * @my_rsv: the reservation + * We first find a reservable space after the goal, then from there, + * we check the bitmap for the first free block after it. If there is + * no free block until the end of group, then the whole group is full, + * we failed. Otherwise, check if the free block is inside the expected + * reservable space, if so, we succeed. * - * @grp_goal: The goal (group-relative). It is where the search for a - * free reservable space should start from. - * if we have a goal(goal >0 ), then start from there, - * no goal(goal = -1), we start from the first block - * of the group. + * If the first free block is outside the reservable space, then start + * from the first free block, we search for next available space, and + * go on. * - * @sb: the super block - * @group: the group we are trying to allocate in - * @bitmap_bh: the block group block bitmap + * on succeed, a new reservation will be found and inserted into the + * list. It contains at least one free block, and it does not overlap + * with other reservation windows. * + * Return: 0 on success, -1 if we failed to find a reservation window + * in this group */ static int alloc_new_reservation(struct ext2_reserve_window_node *my_rsv, ext2_grpblk_t grp_goal, struct super_block *sb, |