/* * the_nilfs.h - the_nilfs shared structure. * * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation. * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA * * Written by Ryusuke Konishi <ryusuke@osrg.net> * */ #ifndef _THE_NILFS_H #define _THE_NILFS_H #include <linux/types.h> #include <linux/buffer_head.h> #include <linux/fs.h> #include <linux/blkdev.h> #include <linux/backing-dev.h> #include "sb.h" /* the_nilfs struct */ enum { THE_NILFS_INIT = 0, /* Information from super_block is set */ THE_NILFS_LOADED, /* Roll-back/roll-forward has done and the latest checkpoint was loaded */ THE_NILFS_DISCONTINUED, /* 'next' pointer chain has broken */ THE_NILFS_GC_RUNNING, /* gc process is running */ }; /** * struct the_nilfs - struct to supervise multiple nilfs mount points * @ns_flags: flags * @ns_count: reference count * @ns_list: list head for nilfs_list * @ns_bdev: block device * @ns_bdi: backing dev info * @ns_writer: back pointer to writable nilfs_sb_info * @ns_sem: semaphore for shared states * @ns_super_sem: semaphore for global operations across super block instances * @ns_mount_mutex: mutex protecting mount process of nilfs * @ns_writer_sem: semaphore protecting ns_writer attach/detach * @ns_current: back pointer to current mount * @ns_sbh: buffer heads of on-disk super blocks * @ns_sbp: pointers to super block data * @ns_sbwtime: previous write time of super blocks * @ns_sbsize: size of valid data in super block * @ns_supers: list of nilfs super block structs * @ns_seg_seq: segment sequence counter * @ns_segnum: index number of the latest full segment. * @ns_nextnum: index number of the full segment index to be used next * @ns_pseg_offset: offset of next partial segment in the current full segment * @ns_cno: next checkpoint number * @ns_ctime: write time of the last segment * @ns_nongc_ctime: write time of the last segment not for cleaner operation * @ns_ndirtyblks: Number of dirty data blocks * @ns_last_segment_lock: lock protecting fields for the latest segment * @ns_last_pseg: start block number of the latest segment * @ns_last_seq: sequence value of the latest segment * @ns_last_cno: checkpoint number of the latest segment * @ns_prot_seq: least sequence number of segments which must not be reclaimed * @ns_free_segments_count: counter of free segments * @ns_segctor_sem: segment constructor semaphore * @ns_dat: DAT file inode * @ns_cpfile: checkpoint file inode * @ns_sufile: segusage file inode * @ns_gc_dat: shadow inode of the DAT file inode for GC * @ns_gc_inodes: dummy inodes to keep live blocks * @ns_gc_inodes_h: hash list to keep dummy inode holding live blocks * @ns_blocksize_bits: bit length of block size * @ns_nsegments: number of segments in filesystem * @ns_blocks_per_segment: number of blocks per segment * @ns_r_segments_percentage: reserved segments percentage * @ns_nrsvsegs: number of reserved segments * @ns_first_data_block: block number of first data block * @ns_inode_size: size of on-disk inode * @ns_first_ino: first not-special inode number * @ns_crc_seed: seed value of CRC32 calculation */ struct the_nilfs { unsigned long ns_flags; atomic_t ns_count; struct list_head ns_list; struct block_device *ns_bdev; struct backing_dev_info *ns_bdi; struct nilfs_sb_info *ns_writer; struct rw_semaphore ns_sem; struct rw_semaphore ns_super_sem; struct mutex ns_mount_mutex; struct rw_semaphore ns_writer_sem; /* * components protected by ns_super_sem */ struct nilfs_sb_info *ns_current; struct list_head ns_supers; /* * used for * - loading the latest checkpoint exclusively. * - allocating a new full segment. * - protecting s_dirt in the super_block struct * (see nilfs_write_super) and the following fields. */ struct buffer_head *ns_sbh[2]; struct nilfs_super_block *ns_sbp[2]; time_t ns_sbwtime[2]; unsigned ns_sbsize; unsigned ns_mount_state; /* * Following fields are dedicated to a writable FS-instance. * Except for the period seeking checkpoint, code outside the segment * constructor must lock a segment semaphore while accessing these * fields. * The writable FS-instance is sole during a lifetime of the_nilfs. */ u64 ns_seg_seq; __u64 ns_segnum; __u64 ns_nextnum; unsigned long ns_pseg_offset; __u64 ns_cno; time_t ns_ctime; time_t ns_nongc_ctime; atomic_t ns_ndirtyblks; /* * The following fields hold information on the latest partial segment * written to disk with a super root. These fields are protected by * ns_last_segment_lock. */ spinlock_t ns_last_segment_lock; sector_t ns_last_pseg; u64 ns_last_seq; __u64 ns_last_cno; u64 ns_prot_seq; unsigned long ns_free_segments_count; struct rw_semaphore ns_segctor_sem; /* * Following fields are lock free except for the period before * the_nilfs is initialized. */ struct inode *ns_dat; struct inode *ns_cpfile; struct inode *ns_sufile; struct inode *ns_gc_dat; /* GC inode list and hash table head */ struct list_head ns_gc_inodes; struct hlist_head *ns_gc_inodes_h; /* Disk layout information (static) */ unsigned int ns_blocksize_bits; unsigned long ns_nsegments; unsigned long ns_blocks_per_segment; unsigned long ns_r_segments_percentage; unsigned long ns_nrsvsegs; unsigned long ns_first_data_block; int ns_inode_size; int ns_first_ino; u32 ns_crc_seed; }; #define NILFS_GCINODE_HASH_BITS 8 #define NILFS_GCINODE_HASH_SIZE (1<<NILFS_GCINODE_HASH_BITS) #define THE_NILFS_FNS(bit, name) \ static inline void set_nilfs_##name(struct the_nilfs *nilfs) \ { \ set_bit(THE_NILFS_##bit, &(nilfs)->ns_flags); \ } \ static inline void clear_nilfs_##name(struct the_nilfs *nilfs) \ { \ clear_bit(THE_NILFS_##bit, &(nilfs)->ns_flags); \ } \ static inline int nilfs_##name(struct the_nilfs *nilfs) \ { \ return test_bit(THE_NILFS_##bit, &(nilfs)->ns_flags); \ } THE_NILFS_FNS(INIT, init) THE_NILFS_FNS(LOADED, loaded) THE_NILFS_FNS(DISCONTINUED, discontinued) THE_NILFS_FNS(GC_RUNNING, gc_running) /* Minimum interval of periodical update of superblocks (in seconds) */ #define NILFS_SB_FREQ 10 #define NILFS_ALTSB_FREQ 60 /* spare superblock */ static inline int nilfs_sb_need_update(struct the_nilfs *nilfs) { u64 t = get_seconds(); return t < nilfs->ns_sbwtime[0] || t > nilfs->ns_sbwtime[0] + NILFS_SB_FREQ; } static inline int nilfs_altsb_need_update(struct the_nilfs *nilfs) { u64 t = get_seconds(); struct nilfs_super_block **sbp = nilfs->ns_sbp; return sbp[1] && t > nilfs->ns_sbwtime[1] + NILFS_ALTSB_FREQ; } void nilfs_set_last_segment(struct the_nilfs *, sector_t, u64, __u64); struct the_nilfs *find_or_create_nilfs(struct block_device *); void put_nilfs(struct the_nilfs *); int init_nilfs(struct the_nilfs *, struct nilfs_sb_info *, char *); int load_nilfs(struct the_nilfs *, struct nilfs_sb_info *); int nilfs_count_free_blocks(struct the_nilfs *, sector_t *); struct nilfs_sb_info *nilfs_find_sbinfo(struct the_nilfs *, int, __u64); int nilfs_checkpoint_is_mounted(struct the_nilfs *, __u64, int); int nilfs_near_disk_full(struct the_nilfs *); void nilfs_fall_back_super_block(struct the_nilfs *); void nilfs_swap_super_block(struct the_nilfs *); static inline void get_nilfs(struct the_nilfs *nilfs) { /* Caller must have at least one reference of the_nilfs. */ atomic_inc(&nilfs->ns_count); } static inline void nilfs_attach_writer(struct the_nilfs *nilfs, struct nilfs_sb_info *sbi) { down_write(&nilfs->ns_writer_sem); nilfs->ns_writer = sbi; up_write(&nilfs->ns_writer_sem); } static inline void nilfs_detach_writer(struct the_nilfs *nilfs, struct nilfs_sb_info *sbi) { down_write(&nilfs->ns_writer_sem); if (sbi == nilfs->ns_writer) nilfs->ns_writer = NULL; up_write(&nilfs->ns_writer_sem); } static inline void nilfs_put_sbinfo(struct nilfs_sb_info *sbi) { if (atomic_dec_and_test(&sbi->s_count)) kfree(sbi); } static inline int nilfs_valid_fs(struct the_nilfs *nilfs) { unsigned valid_fs; down_read(&nilfs->ns_sem); valid_fs = (nilfs->ns_mount_state & NILFS_VALID_FS); up_read(&nilfs->ns_sem); return valid_fs; } static inline void nilfs_get_segment_range(struct the_nilfs *nilfs, __u64 segnum, sector_t *seg_start, sector_t *seg_end) { *seg_start = (sector_t)nilfs->ns_blocks_per_segment * segnum; *seg_end = *seg_start + nilfs->ns_blocks_per_segment - 1; if (segnum == 0) *seg_start = nilfs->ns_first_data_block; } static inline sector_t nilfs_get_segment_start_blocknr(struct the_nilfs *nilfs, __u64 segnum) { return (segnum == 0) ? nilfs->ns_first_data_block : (sector_t)nilfs->ns_blocks_per_segment * segnum; } static inline __u64 nilfs_get_segnum_of_block(struct the_nilfs *nilfs, sector_t blocknr) { sector_t segnum = blocknr; sector_div(segnum, nilfs->ns_blocks_per_segment); return segnum; } static inline void nilfs_terminate_segment(struct the_nilfs *nilfs, sector_t seg_start, sector_t seg_end) { /* terminate the current full segment (used in case of I/O-error) */ nilfs->ns_pseg_offset = seg_end - seg_start + 1; } static inline void nilfs_shift_to_next_segment(struct the_nilfs *nilfs) { /* move forward with a full segment */ nilfs->ns_segnum = nilfs->ns_nextnum; nilfs->ns_pseg_offset = 0; nilfs->ns_seg_seq++; } static inline __u64 nilfs_last_cno(struct the_nilfs *nilfs) { __u64 cno; spin_lock(&nilfs->ns_last_segment_lock); cno = nilfs->ns_last_cno; spin_unlock(&nilfs->ns_last_segment_lock); return cno; } static inline int nilfs_segment_is_active(struct the_nilfs *nilfs, __u64 n) { return n == nilfs->ns_segnum || n == nilfs->ns_nextnum; } #endif /* _THE_NILFS_H */