forked from Minki/linux
cece552074
will reduce some lines of segment constructor. Previously, the state was complexly controlled through a list of segments in order to keep consistency in meta data of usage state of segments. Instead, this presents ``calculated'' active flags to userland cleaner program and stop maintaining its real flag on disk. Only by this fake flag, the cleaner cannot exactly know if each segment is reclaimable or not. However, the recent extension of nilfs_sustat ioctl struct (nilfs2-extend-nilfs_sustat-ioctl-struct.patch) can prevent the cleaner from reclaiming in-use segment wrongly. So, now I can apply this for simplification. Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
289 lines
9.0 KiB
C
289 lines
9.0 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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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*
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* Written by Ryusuke Konishi <ryusuke@osrg.net>
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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/fs.h>
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#include <linux/blkdev.h>
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#include <linux/backing-dev.h>
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#include "sb.h"
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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_LOADED, /* Roll-back/roll-forward has done and
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the latest checkpoint was loaded */
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THE_NILFS_DISCONTINUED, /* 'next' pointer chain has broken */
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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_count: reference count
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* @ns_bdev: block device
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* @ns_bdi: backing dev info
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* @ns_writer: back pointer to writable nilfs_sb_info
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* @ns_sem: semaphore for shared states
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* @ns_writer_mutex: mutex protecting ns_writer attach/detach
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* @ns_writer_refcount: number of referrers on ns_writer
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* @ns_sbh: buffer head of the on-disk super block
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* @ns_sbp: pointer to the super block data
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* @ns_supers: list of nilfs super block structs
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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_free_segments_count: counter of free segments
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* @ns_segctor_sem: segment constructor semaphore
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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_gc_dat: shadow inode of the DAT file inode for GC
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* @ns_gc_inodes: dummy inodes to keep live blocks
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* @ns_gc_inodes_h: hash list to keep dummy inode holding live blocks
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* @ns_blocksize_bits: bit length of 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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*/
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struct the_nilfs {
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unsigned long ns_flags;
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atomic_t ns_count;
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struct block_device *ns_bdev;
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struct backing_dev_info *ns_bdi;
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struct nilfs_sb_info *ns_writer;
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struct rw_semaphore ns_sem;
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struct mutex ns_writer_mutex;
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atomic_t ns_writer_refcount;
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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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* - protecting s_dirt in the super_block struct
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* (see nilfs_write_super) and the following fields.
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*/
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struct buffer_head *ns_sbh;
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struct nilfs_super_block *ns_sbp;
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unsigned ns_mount_state;
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struct list_head ns_supers;
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/*
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* Following fields are dedicated to a writable FS-instance.
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* Except for the period seeking checkpoint, code outside the segment
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* constructor must lock a segment semaphore while accessing these
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* fields.
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* The writable FS-instance is sole during a lifetime of the_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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unsigned long ns_free_segments_count;
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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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struct inode *ns_gc_dat;
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/* GC inode list and hash table head */
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struct list_head ns_gc_inodes;
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struct hlist_head *ns_gc_inodes_h;
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/* Disk layout information (static) */
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unsigned int ns_blocksize_bits;
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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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};
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#define NILFS_GCINODE_HASH_BITS 8
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#define NILFS_GCINODE_HASH_SIZE (1<<NILFS_GCINODE_HASH_BITS)
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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(LOADED, loaded)
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THE_NILFS_FNS(DISCONTINUED, discontinued)
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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 block_device *);
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void put_nilfs(struct the_nilfs *);
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int init_nilfs(struct the_nilfs *, struct nilfs_sb_info *, char *);
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int load_nilfs(struct the_nilfs *, struct nilfs_sb_info *);
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int nilfs_count_free_blocks(struct the_nilfs *, sector_t *);
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int nilfs_checkpoint_is_mounted(struct the_nilfs *, __u64, int);
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int nilfs_near_disk_full(struct the_nilfs *);
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static inline void get_nilfs(struct the_nilfs *nilfs)
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{
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/* Caller must have at least one reference of the_nilfs. */
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atomic_inc(&nilfs->ns_count);
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}
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static inline struct nilfs_sb_info *nilfs_get_writer(struct the_nilfs *nilfs)
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{
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if (atomic_inc_and_test(&nilfs->ns_writer_refcount))
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mutex_lock(&nilfs->ns_writer_mutex);
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return nilfs->ns_writer;
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}
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static inline void nilfs_put_writer(struct the_nilfs *nilfs)
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{
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if (atomic_add_negative(-1, &nilfs->ns_writer_refcount))
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mutex_unlock(&nilfs->ns_writer_mutex);
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}
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static inline void
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nilfs_attach_writer(struct the_nilfs *nilfs, struct nilfs_sb_info *sbi)
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{
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mutex_lock(&nilfs->ns_writer_mutex);
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nilfs->ns_writer = sbi;
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mutex_unlock(&nilfs->ns_writer_mutex);
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}
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static inline void
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nilfs_detach_writer(struct the_nilfs *nilfs, struct nilfs_sb_info *sbi)
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{
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mutex_lock(&nilfs->ns_writer_mutex);
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if (sbi == nilfs->ns_writer)
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nilfs->ns_writer = NULL;
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mutex_unlock(&nilfs->ns_writer_mutex);
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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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#endif /* _THE_NILFS_H */
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