-/*
- * lock the group_info alloc_sem of all the groups
- * belonging to the same buddy cache page. This
- * make sure other parallel operation on the buddy
- * cache doesn't happen whild holding the buddy cache
- * lock
- */
-int ext4_mb_get_buddy_cache_lock(struct super_block *sb, ext4_group_t group)
-{
- int i;
- int block, pnum;
- int blocks_per_page;
- int groups_per_page;
- ext4_group_t ngroups = ext4_get_groups_count(sb);
- ext4_group_t first_group;
- struct ext4_group_info *grp;
-
- blocks_per_page = PAGE_CACHE_SIZE / sb->s_blocksize;
- /*
- * the buddy cache inode stores the block bitmap
- * and buddy information in consecutive blocks.
- * So for each group we need two blocks.
- */
- block = group * 2;
- pnum = block / blocks_per_page;
- first_group = pnum * blocks_per_page / 2;
-
- groups_per_page = blocks_per_page >> 1;
- if (groups_per_page == 0)
- groups_per_page = 1;
- /* read all groups the page covers into the cache */
- for (i = 0; i < groups_per_page; i++) {
-
- if ((first_group + i) >= ngroups)
- break;
- grp = ext4_get_group_info(sb, first_group + i);
- /* take all groups write allocation
- * semaphore. This make sure there is
- * no block allocation going on in any
- * of that groups
- */
- down_write_nested(&grp->alloc_sem, i);
- }
- return i;
-}
-
-void ext4_mb_put_buddy_cache_lock(struct super_block *sb,
- ext4_group_t group, int locked_group)
-{
- int i;
- int block, pnum;
- int blocks_per_page;
- ext4_group_t first_group;
- struct ext4_group_info *grp;
-
- blocks_per_page = PAGE_CACHE_SIZE / sb->s_blocksize;
- /*
- * the buddy cache inode stores the block bitmap
- * and buddy information in consecutive blocks.
- * So for each group we need two blocks.
- */
- block = group * 2;
- pnum = block / blocks_per_page;
- first_group = pnum * blocks_per_page / 2;
- /* release locks on all the groups */
- for (i = 0; i < locked_group; i++) {
-
- grp = ext4_get_group_info(sb, first_group + i);
- /* take all groups write allocation
- * semaphore. This make sure there is
- * no block allocation going on in any
- * of that groups
- */
- up_write(&grp->alloc_sem);
- }
-
-}
-