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Diffstat (limited to 'fs/nilfs2/the_nilfs.h')
| -rw-r--r-- | fs/nilfs2/the_nilfs.h | 396 |
1 files changed, 396 insertions, 0 deletions
diff --git a/fs/nilfs2/the_nilfs.h b/fs/nilfs2/the_nilfs.h new file mode 100644 index 000000000..23778d385 --- /dev/null +++ b/fs/nilfs2/the_nilfs.h @@ -0,0 +1,396 @@ +/* + * 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/rbtree.h> +#include <linux/fs.h> +#include <linux/blkdev.h> +#include <linux/backing-dev.h> +#include <linux/slab.h> + +struct nilfs_sc_info; +struct nilfs_sysfs_dev_subgroups; + +/* the_nilfs struct */ +enum { + THE_NILFS_INIT = 0, /* Information from super_block is set */ + THE_NILFS_DISCONTINUED, /* 'next' pointer chain has broken */ + THE_NILFS_GC_RUNNING, /* gc process is running */ + THE_NILFS_SB_DIRTY, /* super block is dirty */ +}; + +/** + * struct the_nilfs - struct to supervise multiple nilfs mount points + * @ns_flags: flags + * @ns_flushed_device: flag indicating if all volatile data was flushed + * @ns_bdev: block device + * @ns_sem: semaphore for shared states + * @ns_snapshot_mount_mutex: mutex to protect snapshot mounts + * @ns_sbh: buffer heads of on-disk super blocks + * @ns_sbp: pointers to super block data + * @ns_sbwtime: previous write time of super block + * @ns_sbwcount: write count of super block + * @ns_sbsize: size of valid data in super block + * @ns_mount_state: file system state + * @ns_sb_update_freq: interval of periodical update of superblocks (in seconds) + * @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_prev_seq: base sequence number used to decide if advance log cursor + * @ns_writer: log writer + * @ns_segctor_sem: semaphore protecting log write + * @ns_dat: DAT file inode + * @ns_cpfile: checkpoint file inode + * @ns_sufile: segusage file inode + * @ns_cptree: rb-tree of all mounted checkpoints (nilfs_root) + * @ns_cptree_lock: lock protecting @ns_cptree + * @ns_dirty_files: list of dirty files + * @ns_inode_lock: lock protecting @ns_dirty_files + * @ns_gc_inodes: dummy inodes to keep live blocks + * @ns_next_generation: next generation number for inodes + * @ns_next_gen_lock: lock protecting @ns_next_generation + * @ns_mount_opt: mount options + * @ns_resuid: uid for reserved blocks + * @ns_resgid: gid for reserved blocks + * @ns_interval: checkpoint creation interval + * @ns_watermark: watermark for the number of dirty buffers + * @ns_blocksize_bits: bit length of block size + * @ns_blocksize: 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 + * @ns_dev_kobj: /sys/fs/<nilfs>/<device> + * @ns_dev_kobj_unregister: completion state + * @ns_dev_subgroups: <device> subgroups pointer + */ +struct the_nilfs { + unsigned long ns_flags; + int ns_flushed_device; + + struct block_device *ns_bdev; + struct rw_semaphore ns_sem; + struct mutex ns_snapshot_mount_mutex; + + /* + * used for + * - loading the latest checkpoint exclusively. + * - allocating a new full segment. + */ + struct buffer_head *ns_sbh[2]; + struct nilfs_super_block *ns_sbp[2]; + time_t ns_sbwtime; + unsigned ns_sbwcount; + unsigned ns_sbsize; + unsigned ns_mount_state; + unsigned ns_sb_update_freq; + + /* + * 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; + u64 ns_prev_seq; + + struct nilfs_sc_info *ns_writer; + 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; + + /* Checkpoint tree */ + struct rb_root ns_cptree; + spinlock_t ns_cptree_lock; + + /* Dirty inode list */ + struct list_head ns_dirty_files; + spinlock_t ns_inode_lock; + + /* GC inode list */ + struct list_head ns_gc_inodes; + + /* Inode allocator */ + u32 ns_next_generation; + spinlock_t ns_next_gen_lock; + + /* Mount options */ + unsigned long ns_mount_opt; + + uid_t ns_resuid; + gid_t ns_resgid; + unsigned long ns_interval; + unsigned long ns_watermark; + + /* Disk layout information (static) */ + unsigned int ns_blocksize_bits; + unsigned int ns_blocksize; + 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; + + /* /sys/fs/<nilfs>/<device> */ + struct kobject ns_dev_kobj; + struct completion ns_dev_kobj_unregister; + struct nilfs_sysfs_dev_subgroups *ns_dev_subgroups; +}; + +#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(DISCONTINUED, discontinued) +THE_NILFS_FNS(GC_RUNNING, gc_running) +THE_NILFS_FNS(SB_DIRTY, sb_dirty) + +/* + * Mount option operations + */ +#define nilfs_clear_opt(nilfs, opt) \ + do { (nilfs)->ns_mount_opt &= ~NILFS_MOUNT_##opt; } while (0) +#define nilfs_set_opt(nilfs, opt) \ + do { (nilfs)->ns_mount_opt |= NILFS_MOUNT_##opt; } while (0) +#define nilfs_test_opt(nilfs, opt) ((nilfs)->ns_mount_opt & NILFS_MOUNT_##opt) +#define nilfs_write_opt(nilfs, mask, opt) \ + do { (nilfs)->ns_mount_opt = \ + (((nilfs)->ns_mount_opt & ~NILFS_MOUNT_##mask) | \ + NILFS_MOUNT_##opt); \ + } while (0) + +/** + * struct nilfs_root - nilfs root object + * @cno: checkpoint number + * @rb_node: red-black tree node + * @count: refcount of this structure + * @nilfs: nilfs object + * @ifile: inode file + * @inodes_count: number of inodes + * @blocks_count: number of blocks + * @snapshot_kobj: /sys/fs/<nilfs>/<device>/mounted_snapshots/<snapshot> + * @snapshot_kobj_unregister: completion state for kernel object + */ +struct nilfs_root { + __u64 cno; + struct rb_node rb_node; + + atomic_t count; + struct the_nilfs *nilfs; + struct inode *ifile; + + atomic64_t inodes_count; + atomic64_t blocks_count; + + /* /sys/fs/<nilfs>/<device>/mounted_snapshots/<snapshot> */ + struct kobject snapshot_kobj; + struct completion snapshot_kobj_unregister; +}; + +/* Special checkpoint number */ +#define NILFS_CPTREE_CURRENT_CNO 0 + +/* Minimum interval of periodical update of superblocks (in seconds) */ +#define NILFS_SB_FREQ 10 + +static inline int nilfs_sb_need_update(struct the_nilfs *nilfs) +{ + u64 t = get_seconds(); + return t < nilfs->ns_sbwtime || + t > nilfs->ns_sbwtime + nilfs->ns_sb_update_freq; +} + +static inline int nilfs_sb_will_flip(struct the_nilfs *nilfs) +{ + int flip_bits = nilfs->ns_sbwcount & 0x0FL; + return (flip_bits != 0x08 && flip_bits != 0x0F); +} + +void nilfs_set_last_segment(struct the_nilfs *, sector_t, u64, __u64); +struct the_nilfs *alloc_nilfs(struct block_device *bdev); +void destroy_nilfs(struct the_nilfs *nilfs); +int init_nilfs(struct the_nilfs *nilfs, struct super_block *sb, char *data); +int load_nilfs(struct the_nilfs *nilfs, struct super_block *sb); +unsigned long nilfs_nrsvsegs(struct the_nilfs *nilfs, unsigned long nsegs); +void nilfs_set_nsegments(struct the_nilfs *nilfs, unsigned long nsegs); +int nilfs_discard_segments(struct the_nilfs *, __u64 *, size_t); +int nilfs_count_free_blocks(struct the_nilfs *, sector_t *); +struct nilfs_root *nilfs_lookup_root(struct the_nilfs *nilfs, __u64 cno); +struct nilfs_root *nilfs_find_or_create_root(struct the_nilfs *nilfs, + __u64 cno); +void nilfs_put_root(struct nilfs_root *root); +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 nilfs_get_root(struct nilfs_root *root) +{ + atomic_inc(&root->count); +} + +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; +} + +static inline int nilfs_flush_device(struct the_nilfs *nilfs) +{ + int err; + + if (!nilfs_test_opt(nilfs, BARRIER) || nilfs->ns_flushed_device) + return 0; + + nilfs->ns_flushed_device = 1; + /* + * the store to ns_flushed_device must not be reordered after + * blkdev_issue_flush(). + */ + smp_wmb(); + + err = blkdev_issue_flush(nilfs->ns_bdev, GFP_KERNEL, NULL); + if (err != -EIO) + err = 0; + return err; +} + +#endif /* _THE_NILFS_H */ |