}
/**
- * 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,
}
/**
- * 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,
projects / linux-2.6-microblaze.git / blobdiff