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diff --git a/fs/nilfs2/the_nilfs.h b/fs/nilfs2/the_nilfs.h
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+/*
+ * 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 */