394 строки
12 KiB
C
394 строки
12 KiB
C
/*
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* the_nilfs.h - the_nilfs shared structure.
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*
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* Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* Written by Ryusuke Konishi.
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*
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*/
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#ifndef _THE_NILFS_H
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#define _THE_NILFS_H
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#include <linux/types.h>
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#include <linux/buffer_head.h>
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#include <linux/rbtree.h>
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#include <linux/fs.h>
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#include <linux/blkdev.h>
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#include <linux/backing-dev.h>
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#include <linux/slab.h>
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#include <linux/refcount.h>
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struct nilfs_sc_info;
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struct nilfs_sysfs_dev_subgroups;
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/* the_nilfs struct */
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enum {
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THE_NILFS_INIT = 0, /* Information from super_block is set */
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THE_NILFS_DISCONTINUED, /* 'next' pointer chain has broken */
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THE_NILFS_GC_RUNNING, /* gc process is running */
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THE_NILFS_SB_DIRTY, /* super block is dirty */
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};
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/**
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* struct the_nilfs - struct to supervise multiple nilfs mount points
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* @ns_flags: flags
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* @ns_flushed_device: flag indicating if all volatile data was flushed
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* @ns_sb: back pointer to super block instance
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* @ns_bdev: block device
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* @ns_sem: semaphore for shared states
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* @ns_snapshot_mount_mutex: mutex to protect snapshot mounts
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* @ns_sbh: buffer heads of on-disk super blocks
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* @ns_sbp: pointers to super block data
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* @ns_sbwtime: previous write time of super block
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* @ns_sbwcount: write count of super block
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* @ns_sbsize: size of valid data in super block
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* @ns_mount_state: file system state
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* @ns_sb_update_freq: interval of periodical update of superblocks (in seconds)
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* @ns_seg_seq: segment sequence counter
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* @ns_segnum: index number of the latest full segment.
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* @ns_nextnum: index number of the full segment index to be used next
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* @ns_pseg_offset: offset of next partial segment in the current full segment
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* @ns_cno: next checkpoint number
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* @ns_ctime: write time of the last segment
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* @ns_nongc_ctime: write time of the last segment not for cleaner operation
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* @ns_ndirtyblks: Number of dirty data blocks
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* @ns_last_segment_lock: lock protecting fields for the latest segment
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* @ns_last_pseg: start block number of the latest segment
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* @ns_last_seq: sequence value of the latest segment
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* @ns_last_cno: checkpoint number of the latest segment
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* @ns_prot_seq: least sequence number of segments which must not be reclaimed
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* @ns_prev_seq: base sequence number used to decide if advance log cursor
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* @ns_writer: log writer
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* @ns_segctor_sem: semaphore protecting log write
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* @ns_dat: DAT file inode
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* @ns_cpfile: checkpoint file inode
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* @ns_sufile: segusage file inode
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* @ns_cptree: rb-tree of all mounted checkpoints (nilfs_root)
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* @ns_cptree_lock: lock protecting @ns_cptree
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* @ns_dirty_files: list of dirty files
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* @ns_inode_lock: lock protecting @ns_dirty_files
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* @ns_gc_inodes: dummy inodes to keep live blocks
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* @ns_next_generation: next generation number for inodes
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* @ns_next_gen_lock: lock protecting @ns_next_generation
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* @ns_mount_opt: mount options
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* @ns_resuid: uid for reserved blocks
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* @ns_resgid: gid for reserved blocks
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* @ns_interval: checkpoint creation interval
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* @ns_watermark: watermark for the number of dirty buffers
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* @ns_blocksize_bits: bit length of block size
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* @ns_blocksize: block size
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* @ns_nsegments: number of segments in filesystem
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* @ns_blocks_per_segment: number of blocks per segment
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* @ns_r_segments_percentage: reserved segments percentage
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* @ns_nrsvsegs: number of reserved segments
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* @ns_first_data_block: block number of first data block
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* @ns_inode_size: size of on-disk inode
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* @ns_first_ino: first not-special inode number
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* @ns_crc_seed: seed value of CRC32 calculation
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* @ns_dev_kobj: /sys/fs/<nilfs>/<device>
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* @ns_dev_kobj_unregister: completion state
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* @ns_dev_subgroups: <device> subgroups pointer
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*/
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struct the_nilfs {
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unsigned long ns_flags;
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int ns_flushed_device;
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struct super_block *ns_sb;
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struct block_device *ns_bdev;
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struct rw_semaphore ns_sem;
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struct mutex ns_snapshot_mount_mutex;
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/*
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* used for
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* - loading the latest checkpoint exclusively.
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* - allocating a new full segment.
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*/
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struct buffer_head *ns_sbh[2];
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struct nilfs_super_block *ns_sbp[2];
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time_t ns_sbwtime;
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unsigned int ns_sbwcount;
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unsigned int ns_sbsize;
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unsigned int ns_mount_state;
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unsigned int ns_sb_update_freq;
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/*
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* The following fields are updated by a writable FS-instance.
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* These fields are protected by ns_segctor_sem outside load_nilfs().
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*/
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u64 ns_seg_seq;
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__u64 ns_segnum;
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__u64 ns_nextnum;
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unsigned long ns_pseg_offset;
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__u64 ns_cno;
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time_t ns_ctime;
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time_t ns_nongc_ctime;
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atomic_t ns_ndirtyblks;
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/*
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* The following fields hold information on the latest partial segment
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* written to disk with a super root. These fields are protected by
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* ns_last_segment_lock.
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*/
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spinlock_t ns_last_segment_lock;
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sector_t ns_last_pseg;
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u64 ns_last_seq;
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__u64 ns_last_cno;
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u64 ns_prot_seq;
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u64 ns_prev_seq;
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struct nilfs_sc_info *ns_writer;
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struct rw_semaphore ns_segctor_sem;
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/*
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* Following fields are lock free except for the period before
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* the_nilfs is initialized.
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*/
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struct inode *ns_dat;
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struct inode *ns_cpfile;
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struct inode *ns_sufile;
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/* Checkpoint tree */
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struct rb_root ns_cptree;
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spinlock_t ns_cptree_lock;
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/* Dirty inode list */
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struct list_head ns_dirty_files;
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spinlock_t ns_inode_lock;
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/* GC inode list */
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struct list_head ns_gc_inodes;
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/* Inode allocator */
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u32 ns_next_generation;
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spinlock_t ns_next_gen_lock;
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/* Mount options */
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unsigned long ns_mount_opt;
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uid_t ns_resuid;
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gid_t ns_resgid;
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unsigned long ns_interval;
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unsigned long ns_watermark;
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/* Disk layout information (static) */
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unsigned int ns_blocksize_bits;
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unsigned int ns_blocksize;
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unsigned long ns_nsegments;
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unsigned long ns_blocks_per_segment;
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unsigned long ns_r_segments_percentage;
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unsigned long ns_nrsvsegs;
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unsigned long ns_first_data_block;
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int ns_inode_size;
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int ns_first_ino;
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u32 ns_crc_seed;
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/* /sys/fs/<nilfs>/<device> */
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struct kobject ns_dev_kobj;
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struct completion ns_dev_kobj_unregister;
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struct nilfs_sysfs_dev_subgroups *ns_dev_subgroups;
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};
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#define THE_NILFS_FNS(bit, name) \
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static inline void set_nilfs_##name(struct the_nilfs *nilfs) \
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{ \
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set_bit(THE_NILFS_##bit, &(nilfs)->ns_flags); \
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} \
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static inline void clear_nilfs_##name(struct the_nilfs *nilfs) \
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{ \
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clear_bit(THE_NILFS_##bit, &(nilfs)->ns_flags); \
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} \
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static inline int nilfs_##name(struct the_nilfs *nilfs) \
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{ \
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return test_bit(THE_NILFS_##bit, &(nilfs)->ns_flags); \
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}
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THE_NILFS_FNS(INIT, init)
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THE_NILFS_FNS(DISCONTINUED, discontinued)
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THE_NILFS_FNS(GC_RUNNING, gc_running)
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THE_NILFS_FNS(SB_DIRTY, sb_dirty)
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/*
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* Mount option operations
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*/
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#define nilfs_clear_opt(nilfs, opt) \
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((nilfs)->ns_mount_opt &= ~NILFS_MOUNT_##opt)
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#define nilfs_set_opt(nilfs, opt) \
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((nilfs)->ns_mount_opt |= NILFS_MOUNT_##opt)
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#define nilfs_test_opt(nilfs, opt) ((nilfs)->ns_mount_opt & NILFS_MOUNT_##opt)
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#define nilfs_write_opt(nilfs, mask, opt) \
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((nilfs)->ns_mount_opt = \
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(((nilfs)->ns_mount_opt & ~NILFS_MOUNT_##mask) | \
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NILFS_MOUNT_##opt)) \
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/**
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* struct nilfs_root - nilfs root object
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* @cno: checkpoint number
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* @rb_node: red-black tree node
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* @count: refcount of this structure
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* @nilfs: nilfs object
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* @ifile: inode file
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* @inodes_count: number of inodes
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* @blocks_count: number of blocks
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* @snapshot_kobj: /sys/fs/<nilfs>/<device>/mounted_snapshots/<snapshot>
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* @snapshot_kobj_unregister: completion state for kernel object
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*/
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struct nilfs_root {
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__u64 cno;
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struct rb_node rb_node;
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refcount_t count;
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struct the_nilfs *nilfs;
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struct inode *ifile;
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atomic64_t inodes_count;
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atomic64_t blocks_count;
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/* /sys/fs/<nilfs>/<device>/mounted_snapshots/<snapshot> */
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struct kobject snapshot_kobj;
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struct completion snapshot_kobj_unregister;
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};
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/* Special checkpoint number */
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#define NILFS_CPTREE_CURRENT_CNO 0
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/* Minimum interval of periodical update of superblocks (in seconds) */
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#define NILFS_SB_FREQ 10
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static inline int nilfs_sb_need_update(struct the_nilfs *nilfs)
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{
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u64 t = get_seconds();
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return t < nilfs->ns_sbwtime ||
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t > nilfs->ns_sbwtime + nilfs->ns_sb_update_freq;
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}
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static inline int nilfs_sb_will_flip(struct the_nilfs *nilfs)
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{
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int flip_bits = nilfs->ns_sbwcount & 0x0FL;
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return (flip_bits != 0x08 && flip_bits != 0x0F);
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}
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void nilfs_set_last_segment(struct the_nilfs *, sector_t, u64, __u64);
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struct the_nilfs *alloc_nilfs(struct super_block *sb);
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void destroy_nilfs(struct the_nilfs *nilfs);
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int init_nilfs(struct the_nilfs *nilfs, struct super_block *sb, char *data);
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int load_nilfs(struct the_nilfs *nilfs, struct super_block *sb);
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unsigned long nilfs_nrsvsegs(struct the_nilfs *nilfs, unsigned long nsegs);
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void nilfs_set_nsegments(struct the_nilfs *nilfs, unsigned long nsegs);
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int nilfs_discard_segments(struct the_nilfs *, __u64 *, size_t);
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int nilfs_count_free_blocks(struct the_nilfs *, sector_t *);
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struct nilfs_root *nilfs_lookup_root(struct the_nilfs *nilfs, __u64 cno);
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struct nilfs_root *nilfs_find_or_create_root(struct the_nilfs *nilfs,
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__u64 cno);
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void nilfs_put_root(struct nilfs_root *root);
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int nilfs_near_disk_full(struct the_nilfs *);
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void nilfs_fall_back_super_block(struct the_nilfs *);
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void nilfs_swap_super_block(struct the_nilfs *);
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static inline void nilfs_get_root(struct nilfs_root *root)
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{
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refcount_inc(&root->count);
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}
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static inline int nilfs_valid_fs(struct the_nilfs *nilfs)
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{
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unsigned int valid_fs;
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down_read(&nilfs->ns_sem);
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valid_fs = (nilfs->ns_mount_state & NILFS_VALID_FS);
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up_read(&nilfs->ns_sem);
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return valid_fs;
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}
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static inline void
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nilfs_get_segment_range(struct the_nilfs *nilfs, __u64 segnum,
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sector_t *seg_start, sector_t *seg_end)
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{
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*seg_start = (sector_t)nilfs->ns_blocks_per_segment * segnum;
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*seg_end = *seg_start + nilfs->ns_blocks_per_segment - 1;
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if (segnum == 0)
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*seg_start = nilfs->ns_first_data_block;
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}
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static inline sector_t
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nilfs_get_segment_start_blocknr(struct the_nilfs *nilfs, __u64 segnum)
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{
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return (segnum == 0) ? nilfs->ns_first_data_block :
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(sector_t)nilfs->ns_blocks_per_segment * segnum;
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}
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static inline __u64
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nilfs_get_segnum_of_block(struct the_nilfs *nilfs, sector_t blocknr)
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{
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sector_t segnum = blocknr;
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sector_div(segnum, nilfs->ns_blocks_per_segment);
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return segnum;
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}
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static inline void
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nilfs_terminate_segment(struct the_nilfs *nilfs, sector_t seg_start,
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sector_t seg_end)
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{
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/* terminate the current full segment (used in case of I/O-error) */
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nilfs->ns_pseg_offset = seg_end - seg_start + 1;
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}
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static inline void nilfs_shift_to_next_segment(struct the_nilfs *nilfs)
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{
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/* move forward with a full segment */
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nilfs->ns_segnum = nilfs->ns_nextnum;
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nilfs->ns_pseg_offset = 0;
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nilfs->ns_seg_seq++;
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}
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static inline __u64 nilfs_last_cno(struct the_nilfs *nilfs)
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{
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__u64 cno;
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spin_lock(&nilfs->ns_last_segment_lock);
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cno = nilfs->ns_last_cno;
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spin_unlock(&nilfs->ns_last_segment_lock);
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return cno;
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}
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static inline int nilfs_segment_is_active(struct the_nilfs *nilfs, __u64 n)
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{
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return n == nilfs->ns_segnum || n == nilfs->ns_nextnum;
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}
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static inline int nilfs_flush_device(struct the_nilfs *nilfs)
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{
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int err;
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if (!nilfs_test_opt(nilfs, BARRIER) || nilfs->ns_flushed_device)
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return 0;
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nilfs->ns_flushed_device = 1;
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/*
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* the store to ns_flushed_device must not be reordered after
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* blkdev_issue_flush().
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*/
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smp_wmb();
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err = blkdev_issue_flush(nilfs->ns_bdev, GFP_KERNEL, NULL);
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if (err != -EIO)
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err = 0;
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return err;
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}
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#endif /* _THE_NILFS_H */
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