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Diffstat (limited to 'fs/nilfs2/the_nilfs.h')
| -rw-r--r-- | fs/nilfs2/the_nilfs.h | 298 |
1 files changed, 298 insertions, 0 deletions
diff --git a/fs/nilfs2/the_nilfs.h b/fs/nilfs2/the_nilfs.h new file mode 100644 index 00000000000..30fe58778d0 --- /dev/null +++ b/fs/nilfs2/the_nilfs.h @@ -0,0 +1,298 @@ +/* + * 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 */ +}; + +/** + * struct the_nilfs - struct to supervise multiple nilfs mount points + * @ns_flags: flags + * @ns_count: reference count + * @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_writer_mutex: mutex protecting ns_writer attach/detach + * @ns_writer_refcount: number of referrers on ns_writer + * @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 block_device *ns_bdev; + struct backing_dev_info *ns_bdi; + struct nilfs_sb_info *ns_writer; + struct rw_semaphore ns_sem; + struct mutex ns_writer_mutex; + atomic_t ns_writer_refcount; + + /* + * 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; + struct list_head ns_supers; + + /* + * 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) + +/* Minimum interval of periodical update of superblocks (in seconds) */ +#define NILFS_SB_FREQ 10 +#define NILFS_ALTSB_FREQ 60 /* spare superblock */ + +void nilfs_set_last_segment(struct the_nilfs *, sector_t, u64, __u64); +struct the_nilfs *alloc_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 *); +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 struct nilfs_sb_info *nilfs_get_writer(struct the_nilfs *nilfs) +{ + if (atomic_inc_and_test(&nilfs->ns_writer_refcount)) + mutex_lock(&nilfs->ns_writer_mutex); + return nilfs->ns_writer; +} + +static inline void nilfs_put_writer(struct the_nilfs *nilfs) +{ + if (atomic_add_negative(-1, &nilfs->ns_writer_refcount)) + mutex_unlock(&nilfs->ns_writer_mutex); +} + +static inline void +nilfs_attach_writer(struct the_nilfs *nilfs, struct nilfs_sb_info *sbi) +{ + mutex_lock(&nilfs->ns_writer_mutex); + nilfs->ns_writer = sbi; + mutex_unlock(&nilfs->ns_writer_mutex); +} + +static inline void +nilfs_detach_writer(struct the_nilfs *nilfs, struct nilfs_sb_info *sbi) +{ + mutex_lock(&nilfs->ns_writer_mutex); + if (sbi == nilfs->ns_writer) + nilfs->ns_writer = NULL; + mutex_unlock(&nilfs->ns_writer_mutex); +} + +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 */ |