fs/nilfs2/alloc.h

   1 /*
   2  * alloc.h - persistent object (dat entry/disk inode) allocator/deallocator
   3  *
   4  * Copyright (C) 2006-2008 Nippon Telegraph and Telephone Corporation.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  19  *
  20  * Original code was written by Koji Sato <koji@osrg.net>.
  21  * Two allocators were unified by Ryusuke Konishi <ryusuke@osrg.net>,
  22  *                                Amagai Yoshiji <amagai@osrg.net>.
  23  */
  24
  25 #ifndef _NILFS_ALLOC_H
  26 #define _NILFS_ALLOC_H
  27
  28 #include <linux/types.h>
  29 #include <linux/buffer_head.h>
  30 #include <linux/fs.h>
  31
  32 /**
  33  * nilfs_palloc_entries_per_group - get the number of entries per group
  34  * @inode: inode of metadata file using this allocator
  35  *
  36  * The number of entries per group is defined by the number of bits
  37  * that a bitmap block can maintain.
  38  */
  39 static inline unsigned long
  40 nilfs_palloc_entries_per_group(const struct inode *inode)
  41 {
  42         return 1UL << (inode->i_blkbits + 3 /* log2(8 = CHAR_BITS) */);
  43 }
  44
  45 int nilfs_palloc_init_blockgroup(struct inode *, unsigned);
  46 int nilfs_palloc_get_entry_block(struct inode *, __u64, int,
  47                                  struct buffer_head **);
  48 void *nilfs_palloc_block_get_entry(const struct inode *, __u64,
  49                                    const struct buffer_head *, void *);
  50
  51 /**
  52  * nilfs_palloc_req - persistent allocator request and reply
  53  * @pr_entry_nr: entry number (vblocknr or inode number)
  54  * @pr_desc_bh: buffer head of the buffer containing block group descriptors
  55  * @pr_bitmap_bh: buffer head of the buffer containing a block group bitmap
  56  * @pr_entry_bh: buffer head of the buffer containing translation entries
  57  */
  58 struct nilfs_palloc_req {
  59         __u64 pr_entry_nr;
  60         struct buffer_head *pr_desc_bh;
  61         struct buffer_head *pr_bitmap_bh;
  62         struct buffer_head *pr_entry_bh;
  63 };
  64
  65 int nilfs_palloc_prepare_alloc_entry(struct inode *,
  66                                      struct nilfs_palloc_req *);
  67 void nilfs_palloc_commit_alloc_entry(struct inode *,
  68                                      struct nilfs_palloc_req *);
  69 void nilfs_palloc_abort_alloc_entry(struct inode *, struct nilfs_palloc_req *);
  70 void nilfs_palloc_commit_free_entry(struct inode *, struct nilfs_palloc_req *);
  71 int nilfs_palloc_prepare_free_entry(struct inode *, struct nilfs_palloc_req *);
  72 void nilfs_palloc_abort_free_entry(struct inode *, struct nilfs_palloc_req *);
  73 int nilfs_palloc_freev(struct inode *, __u64 *, size_t);
  74
  75 #define nilfs_set_bit_atomic            ext2_set_bit_atomic
  76 #define nilfs_clear_bit_atomic          ext2_clear_bit_atomic
  77 #define nilfs_find_next_zero_bit        ext2_find_next_zero_bit
  78
  79 /*
  80  * persistent object allocator cache
  81  */
  82
  83 struct nilfs_bh_assoc {
  84         unsigned long blkoff;
  85         struct buffer_head *bh;
  86 };
  87
  88 struct nilfs_palloc_cache {
  89         spinlock_t lock;
  90         struct nilfs_bh_assoc prev_desc;
  91         struct nilfs_bh_assoc prev_bitmap;
  92         struct nilfs_bh_assoc prev_entry;
  93 };
  94
  95 void nilfs_palloc_setup_cache(struct inode *inode,
  96                               struct nilfs_palloc_cache *cache);
  97 void nilfs_palloc_clear_cache(struct inode *inode);
  98 void nilfs_palloc_destroy_cache(struct inode *inode);
  99
 100 #endif  /* _NILFS_ALLOC_H */