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linux/fs/nilfs2/the_nilfs.h
Ryusuke Konishi 9860f43405 nilfs2: eliminate the shared counter and spinlock for i_generation 
Use get_random_u32() as the source for inode->i_generation for new inodes,
and eliminate the original source, the shared counter ns_next_generation
along with its exclusive access spinlock ns_next_gen_lock.

Link: https://lkml.kernel.org/r/20240826174116.5008-5-konishi.ryusuke@gmail.com
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Cc: Huang Xiaojia <huangxiaojia2@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-09-01 20:43:43 -07:00

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/* SPDX-License-Identifier: GPL-2.0+ */
/*
* the_nilfs shared structure.
*
* Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
*
* 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>
#include <linux/refcount.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 */
THE_NILFS_PURGING, /* disposing dirty files for cleanup */
};
/**
* 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_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];
time64_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;
time64_t ns_ctime;
time64_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;
/* 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;
unsigned 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)
THE_NILFS_FNS(PURGING, purging)
/*
* 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)
/**
* 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;
refcount_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 = ktime_get_real_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 super_block *sb);
void destroy_nilfs(struct the_nilfs *nilfs);
int init_nilfs(struct the_nilfs *nilfs, struct super_block *sb);
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)
{
refcount_inc(&root->count);
}
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;
}
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);
if (err != -EIO)
err = 0;
return err;
}
#endif /* _THE_NILFS_H */
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