1 /* 2 * segbuf.h - NILFS Segment buffer prototypes and definitions 3 * 4 * Copyright (C) 2005-2008 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 * Written by Ryusuke Konishi <ryusuke@osrg.net> 21 * 22 */ 23 #ifndef _NILFS_SEGBUF_H 24 #define _NILFS_SEGBUF_H 25 26 #include <linux/fs.h> 27 #include <linux/buffer_head.h> 28 #include <linux/bio.h> 29 #include <linux/completion.h> 30 31 /** 32 * struct nilfs_segsum_info - On-memory segment summary 33 * @flags: Flags 34 * @nfinfo: Number of file information structures 35 * @nblocks: Number of blocks included in the partial segment 36 * @nsumblk: Number of summary blocks 37 * @sumbytes: Byte count of segment summary 38 * @nfileblk: Total number of file blocks 39 * @seg_seq: Segment sequence number 40 * @cno: Checkpoint number 41 * @ctime: Creation time 42 * @next: Block number of the next full segment 43 */ 44 struct nilfs_segsum_info { 45 unsigned int flags; 46 unsigned long nfinfo; 47 unsigned long nblocks; 48 unsigned long nsumblk; 49 unsigned long sumbytes; 50 unsigned long nfileblk; 51 u64 seg_seq; 52 __u64 cno; 53 time_t ctime; 54 sector_t next; 55 }; 56 57 /** 58 * struct nilfs_segment_buffer - Segment buffer 59 * @sb_super: back pointer to a superblock struct 60 * @sb_list: List head to chain this structure 61 * @sb_sum: On-memory segment summary 62 * @sb_segnum: Index number of the full segment 63 * @sb_nextnum: Index number of the next full segment 64 * @sb_fseg_start: Start block number of the full segment 65 * @sb_fseg_end: End block number of the full segment 66 * @sb_pseg_start: Disk block number of partial segment 67 * @sb_rest_blocks: Number of residual blocks in the current segment 68 * @sb_segsum_buffers: List of buffers for segment summaries 69 * @sb_payload_buffers: List of buffers for segment payload 70 * @sb_super_root: Pointer to buffer storing a super root block (if exists) 71 * @sb_nbio: Number of flying bio requests 72 * @sb_err: I/O error status 73 * @sb_bio_event: Completion event of log writing 74 */ 75 struct nilfs_segment_buffer { 76 struct super_block *sb_super; 77 struct list_head sb_list; 78 79 /* Segment information */ 80 struct nilfs_segsum_info sb_sum; 81 __u64 sb_segnum; 82 __u64 sb_nextnum; 83 sector_t sb_fseg_start, sb_fseg_end; 84 sector_t sb_pseg_start; 85 unsigned sb_rest_blocks; 86 87 /* Buffers */ 88 struct list_head sb_segsum_buffers; 89 struct list_head sb_payload_buffers; /* including super root */ 90 struct buffer_head *sb_super_root; 91 92 /* io status */ 93 int sb_nbio; 94 atomic_t sb_err; 95 struct completion sb_bio_event; 96 }; 97 98 #define NILFS_LIST_SEGBUF(head) \ 99 list_entry((head), struct nilfs_segment_buffer, sb_list) 100 #define NILFS_NEXT_SEGBUF(segbuf) NILFS_LIST_SEGBUF((segbuf)->sb_list.next) 101 #define NILFS_PREV_SEGBUF(segbuf) NILFS_LIST_SEGBUF((segbuf)->sb_list.prev) 102 #define NILFS_LAST_SEGBUF(head) NILFS_LIST_SEGBUF((head)->prev) 103 #define NILFS_FIRST_SEGBUF(head) NILFS_LIST_SEGBUF((head)->next) 104 #define NILFS_SEGBUF_IS_LAST(segbuf, head) ((segbuf)->sb_list.next == (head)) 105 106 #define nilfs_for_each_segbuf_before(s, t, h) \ 107 for ((s) = NILFS_FIRST_SEGBUF(h); (s) != (t); \ 108 (s) = NILFS_NEXT_SEGBUF(s)) 109 110 #define NILFS_SEGBUF_FIRST_BH(head) \ 111 (list_entry((head)->next, struct buffer_head, b_assoc_buffers)) 112 #define NILFS_SEGBUF_NEXT_BH(bh) \ 113 (list_entry((bh)->b_assoc_buffers.next, struct buffer_head, \ 114 b_assoc_buffers)) 115 #define NILFS_SEGBUF_BH_IS_LAST(bh, head) ((bh)->b_assoc_buffers.next == head) 116 117 extern struct kmem_cache *nilfs_segbuf_cachep; 118 119 struct nilfs_segment_buffer *nilfs_segbuf_new(struct super_block *); 120 void nilfs_segbuf_free(struct nilfs_segment_buffer *); 121 void nilfs_segbuf_map(struct nilfs_segment_buffer *, __u64, unsigned long, 122 struct the_nilfs *); 123 void nilfs_segbuf_map_cont(struct nilfs_segment_buffer *segbuf, 124 struct nilfs_segment_buffer *prev); 125 void nilfs_segbuf_set_next_segnum(struct nilfs_segment_buffer *, __u64, 126 struct the_nilfs *); 127 int nilfs_segbuf_reset(struct nilfs_segment_buffer *, unsigned, time_t, __u64); 128 int nilfs_segbuf_extend_segsum(struct nilfs_segment_buffer *); 129 int nilfs_segbuf_extend_payload(struct nilfs_segment_buffer *, 130 struct buffer_head **); 131 void nilfs_segbuf_fill_in_segsum(struct nilfs_segment_buffer *); 132 133 static inline int nilfs_segbuf_simplex(struct nilfs_segment_buffer *segbuf) 134 { 135 unsigned int flags = segbuf->sb_sum.flags; 136 137 return (flags & (NILFS_SS_LOGBGN | NILFS_SS_LOGEND)) == 138 (NILFS_SS_LOGBGN | NILFS_SS_LOGEND); 139 } 140 141 static inline int nilfs_segbuf_empty(struct nilfs_segment_buffer *segbuf) 142 { 143 return segbuf->sb_sum.nblocks == segbuf->sb_sum.nsumblk; 144 } 145 146 static inline void 147 nilfs_segbuf_add_segsum_buffer(struct nilfs_segment_buffer *segbuf, 148 struct buffer_head *bh) 149 { 150 list_add_tail(&bh->b_assoc_buffers, &segbuf->sb_segsum_buffers); 151 segbuf->sb_sum.nblocks++; 152 segbuf->sb_sum.nsumblk++; 153 } 154 155 static inline void 156 nilfs_segbuf_add_payload_buffer(struct nilfs_segment_buffer *segbuf, 157 struct buffer_head *bh) 158 { 159 list_add_tail(&bh->b_assoc_buffers, &segbuf->sb_payload_buffers); 160 segbuf->sb_sum.nblocks++; 161 } 162 163 static inline void 164 nilfs_segbuf_add_file_buffer(struct nilfs_segment_buffer *segbuf, 165 struct buffer_head *bh) 166 { 167 get_bh(bh); 168 nilfs_segbuf_add_payload_buffer(segbuf, bh); 169 segbuf->sb_sum.nfileblk++; 170 } 171 172 void nilfs_clear_logs(struct list_head *logs); 173 void nilfs_truncate_logs(struct list_head *logs, 174 struct nilfs_segment_buffer *last); 175 int nilfs_write_logs(struct list_head *logs, struct the_nilfs *nilfs); 176 int nilfs_wait_on_logs(struct list_head *logs); 177 void nilfs_add_checksums_on_logs(struct list_head *logs, u32 seed); 178 179 static inline void nilfs_destroy_logs(struct list_head *logs) 180 { 181 nilfs_truncate_logs(logs, NULL); 182 } 183 184 #endif /* _NILFS_SEGBUF_H */ 185