cregit-Linux how code gets into the kernel

Release 4.10 fs/nilfs2/the_nilfs.h

Directory: fs/nilfs2
/*
 * 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.
 *
 * Written by Ryusuke Konishi.
 *
 */

#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_sb: back pointer to super block instance
 * @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 super_block     *ns_sb;
	
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 int		ns_sbwcount;
	
unsigned int		ns_sbsize;
	
unsigned int		ns_mount_state;
	
unsigned int		ns_sb_update_freq;

	/*
         * The following fields are updated by a writable FS-instance.
         * These fields are protected by ns_segctor_sem outside load_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)  \
	((nilfs)->ns_mount_opt &= ~NILFS_MOUNT_##opt)

#define nilfs_set_opt(nilfs, opt)  \
	((nilfs)->ns_mount_opt |= NILFS_MOUNT_##opt)

#define nilfs_test_opt(nilfs, opt) ((nilfs)->ns_mount_opt & NILFS_MOUNT_##opt)

#define nilfs_write_opt(nilfs, mask, opt)				\
	((nilfs)->ns_mount_opt =                                        \
                (((nilfs)->ns_mount_opt & ~NILFS_MOUNT_##mask) |        \
                 NILFS_MOUNT_##opt))					\

/**
 * 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; }

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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); }

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void nilfs_set_last_segment(struct the_nilfs *, sector_t, u64, __u64); struct the_nilfs *alloc_nilfs(struct super_block *sb); 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); }

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static inline int nilfs_valid_fs(struct the_nilfs *nilfs) { unsigned int valid_fs; down_read(&nilfs->ns_sem); valid_fs = (nilfs->ns_mount_state & NILFS_VALID_FS); up_read(&nilfs->ns_sem); return valid_fs; }

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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; }

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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; }

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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; }

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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; }

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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++; }

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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; }

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static inline int nilfs_segment_is_active(struct the_nilfs *nilfs, __u64 n) { return n == nilfs->ns_segnum || n == nilfs->ns_nextnum; }

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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; }

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#endif /* _THE_NILFS_H */

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vyacheslav dubeykovyacheslav dubeyko353.32%411.11%
artem bityutskiyartem bityutskiy10.09%12.78%
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Directory: fs/nilfs2
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