diff options
Diffstat (limited to 'fs/nilfs2')
| -rw-r--r-- | fs/nilfs2/cpfile.c | 6 | ||||
| -rw-r--r-- | fs/nilfs2/sb.h | 1 | ||||
| -rw-r--r-- | fs/nilfs2/super.c | 256 | ||||
| -rw-r--r-- | fs/nilfs2/the_nilfs.c | 113 | ||||
| -rw-r--r-- | fs/nilfs2/the_nilfs.h | 23 |
5 files changed, 226 insertions, 173 deletions
diff --git a/fs/nilfs2/cpfile.c b/fs/nilfs2/cpfile.c index 300f1cdfa86..cadd36b14d0 100644 --- a/fs/nilfs2/cpfile.c +++ b/fs/nilfs2/cpfile.c @@ -864,11 +864,11 @@ int nilfs_cpfile_change_cpmode(struct inode *cpfile, __u64 cno, int mode) case NILFS_CHECKPOINT: /* * Check for protecting existing snapshot mounts: - * bd_mount_sem is used to make this operation atomic and + * ns_mount_mutex is used to make this operation atomic and * exclusive with a new mount job. Though it doesn't cover * umount, it's enough for the purpose. */ - down(&nilfs->ns_bdev->bd_mount_sem); + mutex_lock(&nilfs->ns_mount_mutex); if (nilfs_checkpoint_is_mounted(nilfs, cno, 1)) { /* Current implementation does not have to protect plain read-only mounts since they are exclusive @@ -877,7 +877,7 @@ int nilfs_cpfile_change_cpmode(struct inode *cpfile, __u64 cno, int mode) ret = -EBUSY; } else ret = nilfs_cpfile_clear_snapshot(cpfile, cno); - up(&nilfs->ns_bdev->bd_mount_sem); + mutex_unlock(&nilfs->ns_mount_mutex); return ret; case NILFS_SNAPSHOT: return nilfs_cpfile_set_snapshot(cpfile, cno); diff --git a/fs/nilfs2/sb.h b/fs/nilfs2/sb.h index adccd4fc654..0776ccc2504 100644 --- a/fs/nilfs2/sb.h +++ b/fs/nilfs2/sb.h @@ -60,6 +60,7 @@ struct nilfs_sb_info { struct super_block *s_super; /* reverse pointer to super_block */ struct the_nilfs *s_nilfs; struct list_head s_list; /* list head for nilfs->ns_supers */ + atomic_t s_count; /* reference count */ /* Segment constructor */ struct list_head s_dirty_files; /* dirty files list */ diff --git a/fs/nilfs2/super.c b/fs/nilfs2/super.c index 6989b03e97a..1777a3467bd 100644 --- a/fs/nilfs2/super.c +++ b/fs/nilfs2/super.c @@ -65,9 +65,8 @@ MODULE_DESCRIPTION("A New Implementation of the Log-structured Filesystem " "(NILFS)"); MODULE_LICENSE("GPL"); +static void nilfs_write_super(struct super_block *sb); static int nilfs_remount(struct super_block *sb, int *flags, char *data); -static int test_exclusive_mount(struct file_system_type *fs_type, - struct block_device *bdev, int flags); /** * nilfs_error() - report failure condition on a filesystem @@ -315,6 +314,11 @@ static void nilfs_put_super(struct super_block *sb) struct nilfs_sb_info *sbi = NILFS_SB(sb); struct the_nilfs *nilfs = sbi->s_nilfs; + lock_kernel(); + + if (sb->s_dirt) + nilfs_write_super(sb); + nilfs_detach_segment_constructor(sbi); if (!(sb->s_flags & MS_RDONLY)) { @@ -323,12 +327,18 @@ static void nilfs_put_super(struct super_block *sb) nilfs_commit_super(sbi, 1); up_write(&nilfs->ns_sem); } + down_write(&nilfs->ns_super_sem); + if (nilfs->ns_current == sbi) + nilfs->ns_current = NULL; + up_write(&nilfs->ns_super_sem); nilfs_detach_checkpoint(sbi); put_nilfs(sbi->s_nilfs); sbi->s_super = NULL; sb->s_fs_info = NULL; - kfree(sbi); + nilfs_put_sbinfo(sbi); + + unlock_kernel(); } /** @@ -383,6 +393,8 @@ static int nilfs_sync_fs(struct super_block *sb, int wait) { int err = 0; + nilfs_write_super(sb); + /* This function is called when super block should be written back */ if (wait) err = nilfs_construct_segment(sb); @@ -396,9 +408,9 @@ int nilfs_attach_checkpoint(struct nilfs_sb_info *sbi, __u64 cno) struct buffer_head *bh_cp; int err; - down_write(&nilfs->ns_sem); + down_write(&nilfs->ns_super_sem); list_add(&sbi->s_list, &nilfs->ns_supers); - up_write(&nilfs->ns_sem); + up_write(&nilfs->ns_super_sem); sbi->s_ifile = nilfs_mdt_new( nilfs, sbi->s_super, NILFS_IFILE_INO, NILFS_IFILE_GFP); @@ -436,9 +448,9 @@ int nilfs_attach_checkpoint(struct nilfs_sb_info *sbi, __u64 cno) nilfs_mdt_destroy(sbi->s_ifile); sbi->s_ifile = NULL; - down_write(&nilfs->ns_sem); + down_write(&nilfs->ns_super_sem); list_del_init(&sbi->s_list); - up_write(&nilfs->ns_sem); + up_write(&nilfs->ns_super_sem); return err; } @@ -450,9 +462,9 @@ void nilfs_detach_checkpoint(struct nilfs_sb_info *sbi) nilfs_mdt_clear(sbi->s_ifile); nilfs_mdt_destroy(sbi->s_ifile); sbi->s_ifile = NULL; - down_write(&nilfs->ns_sem); + down_write(&nilfs->ns_super_sem); list_del_init(&sbi->s_list); - up_write(&nilfs->ns_sem); + up_write(&nilfs->ns_super_sem); } static int nilfs_mark_recovery_complete(struct nilfs_sb_info *sbi) @@ -752,7 +764,7 @@ int nilfs_store_magic_and_option(struct super_block *sb, * @silent: silent mode flag * @nilfs: the_nilfs struct * - * This function is called exclusively by bd_mount_mutex. + * This function is called exclusively by nilfs->ns_mount_mutex. * So, the recovery process is protected from other simultaneous mounts. */ static int @@ -773,6 +785,7 @@ nilfs_fill_super(struct super_block *sb, void *data, int silent, get_nilfs(nilfs); sbi->s_nilfs = nilfs; sbi->s_super = sb; + atomic_set(&sbi->s_count, 1); err = init_nilfs(nilfs, sbi, (char *)data); if (err) @@ -870,6 +883,11 @@ nilfs_fill_super(struct super_block *sb, void *data, int silent, goto failed_root; } + down_write(&nilfs->ns_super_sem); + if (!nilfs_test_opt(sbi, SNAPSHOT)) + nilfs->ns_current = sbi; + up_write(&nilfs->ns_super_sem); + return 0; failed_root: @@ -885,7 +903,7 @@ nilfs_fill_super(struct super_block *sb, void *data, int silent, failed_sbi: put_nilfs(nilfs); sb->s_fs_info = NULL; - kfree(sbi); + nilfs_put_sbinfo(sbi); return err; } @@ -898,6 +916,9 @@ static int nilfs_remount(struct super_block *sb, int *flags, char *data) struct nilfs_mount_options old_opts; int err; + lock_kernel(); + + down_write(&nilfs->ns_super_sem); old_sb_flags = sb->s_flags; old_opts.mount_opt = sbi->s_mount_opt; old_opts.snapshot_cno = sbi->s_snapshot_cno; @@ -945,14 +966,12 @@ static int nilfs_remount(struct super_block *sb, int *flags, char *data) * store the current valid flag. (It may have been changed * by fsck since we originally mounted the partition.) */ - down(&sb->s_bdev->bd_mount_sem); - /* Check existing RW-mount */ - if (test_exclusive_mount(sb->s_type, sb->s_bdev, 0)) { + if (nilfs->ns_current && nilfs->ns_current != sbi) { printk(KERN_WARNING "NILFS (device %s): couldn't " - "remount because a RW-mount exists.\n", + "remount because an RW-mount exists.\n", sb->s_id); err = -EBUSY; - goto rw_remount_failed; + goto restore_opts; } if (sbi->s_snapshot_cno != nilfs_last_cno(nilfs)) { printk(KERN_WARNING "NILFS (device %s): couldn't " @@ -960,7 +979,7 @@ static int nilfs_remount(struct super_block *sb, int *flags, char *data) "the latest one.\n", sb->s_id); err = -EINVAL; - goto rw_remount_failed; + goto restore_opts; } sb->s_flags &= ~MS_RDONLY; nilfs_clear_opt(sbi, SNAPSHOT); @@ -968,28 +987,31 @@ static int nilfs_remount(struct super_block *sb, int *flags, char *data) err = nilfs_attach_segment_constructor(sbi); if (err) - goto rw_remount_failed; + goto restore_opts; down_write(&nilfs->ns_sem); nilfs_setup_super(sbi); up_write(&nilfs->ns_sem); - up(&sb->s_bdev->bd_mount_sem); + nilfs->ns_current = sbi; } out: + up_write(&nilfs->ns_super_sem); + unlock_kernel(); return 0; - rw_remount_failed: - up(&sb->s_bdev->bd_mount_sem); restore_opts: sb->s_flags = old_sb_flags; sbi->s_mount_opt = old_opts.mount_opt; sbi->s_snapshot_cno = old_opts.snapshot_cno; + up_write(&nilfs->ns_super_sem); + unlock_kernel(); return err; } struct nilfs_super_data { struct block_device *bdev; + struct nilfs_sb_info *sbi; __u64 cno; int flags; }; @@ -1048,33 +1070,7 @@ static int nilfs_test_bdev_super(struct super_block *s, void *data) { struct nilfs_super_data *sd = data; - return s->s_bdev == sd->bdev; -} - -static int nilfs_test_bdev_super2(struct super_block *s, void *data) -{ - struct nilfs_super_data *sd = data; - int ret; - - if (s->s_bdev != sd->bdev) - return 0; - - if (!((s->s_flags | sd->flags) & MS_RDONLY)) - return 1; /* Reuse an old R/W-mode super_block */ - - if (s->s_flags & sd->flags & MS_RDONLY) { - if (down_read_trylock(&s->s_umount)) { - ret = s->s_root && - (sd->cno == NILFS_SB(s)->s_snapshot_cno); - up_read(&s->s_umount); - /* - * This path is locked with sb_lock by sget(). - * So, drop_super() causes deadlock. - */ - return ret; - } - } - return 0; + return sd->sbi && s->s_fs_info == (void *)sd->sbi; } static int @@ -1082,8 +1078,8 @@ nilfs_get_sb(struct file_system_type *fs_type, int flags, const char *dev_name, void *data, struct vfsmount *mnt) { struct nilfs_super_data sd; - struct super_block *s, *s2; - struct the_nilfs *nilfs = NULL; + struct super_block *s; + struct the_nilfs *nilfs; int err, need_to_close = 1; sd.bdev = open_bdev_exclusive(dev_name, flags, fs_type); @@ -1095,7 +1091,6 @@ nilfs_get_sb(struct file_system_type *fs_type, int flags, * much more information than normal filesystems to identify mount * instance. For snapshot mounts, not only a mount type (ro-mount * or rw-mount) but also a checkpoint number is required. - * The results are passed in sget() using nilfs_super_data. */ sd.cno = 0; sd.flags = flags; @@ -1104,64 +1099,59 @@ nilfs_get_sb(struct file_system_type *fs_type, int flags, goto failed; } - /* - * once the super is inserted into the list by sget, s_umount - * will protect the lockfs code from trying to start a snapshot - * while we are mounting - */ - down(&sd.bdev->bd_mount_sem); - if (!sd.cno && - (err = test_exclusive_mount(fs_type, sd.bdev, flags ^ MS_RDONLY))) { - err = (err < 0) ? : -EBUSY; - goto failed_unlock; + nilfs = find_or_create_nilfs(sd.bdev); + if (!nilfs) { + err = -ENOMEM; + goto failed; } - /* - * Phase-1: search any existent instance and get the_nilfs - */ - s = sget(fs_type, nilfs_test_bdev_super, nilfs_set_bdev_super, &sd); - if (IS_ERR(s)) - goto error_s; - - if (!s->s_root) { - err = -ENOMEM; - nilfs = alloc_nilfs(sd.bdev); - if (!nilfs) - goto cancel_new; - } else { - struct nilfs_sb_info *sbi = NILFS_SB(s); + mutex_lock(&nilfs->ns_mount_mutex); + if (!sd.cno) { /* - * s_umount protects super_block from unmount process; - * It covers pointers of nilfs_sb_info and the_nilfs. + * Check if an exclusive mount exists or not. + * Snapshot mounts coexist with a current mount + * (i.e. rw-mount or ro-mount), whereas rw-mount and + * ro-mount are mutually exclusive. */ - nilfs = sbi->s_nilfs; - get_nilfs(nilfs); - up_write(&s->s_umount); + down_read(&nilfs->ns_super_sem); + if (nilfs->ns_current && + ((nilfs->ns_current->s_super->s_flags ^ flags) + & MS_RDONLY)) { + up_read(&nilfs->ns_super_sem); + err = -EBUSY; + goto failed_unlock; + } + up_read(&nilfs->ns_super_sem); + } - /* - * Phase-2: search specified snapshot or R/W mode super_block - */ - if (!sd.cno) - /* trying to get the latest checkpoint. */ - sd.cno = nilfs_last_cno(nilfs); + /* + * Find existing nilfs_sb_info struct + */ + sd.sbi = nilfs_find_sbinfo(nilfs, !(flags & MS_RDONLY), sd.cno); - s2 = sget(fs_type, nilfs_test_bdev_super2, - nilfs_set_bdev_super, &sd); - deactivate_super(s); - /* - * Although deactivate_super() invokes close_bdev_exclusive() at - * kill_block_super(). Here, s is an existent mount; we need - * one more close_bdev_exclusive() call. - */ - s = s2; - if (IS_ERR(s)) - goto error_s; + if (!sd.cno) + /* trying to get the latest checkpoint. */ + sd.cno = nilfs_last_cno(nilfs); + + /* + * Get super block instance holding the nilfs_sb_info struct. + * A new instance is allocated if no existing mount is present or + * existing instance has been unmounted. + */ + s = sget(fs_type, nilfs_test_bdev_super, nilfs_set_bdev_super, &sd); + if (sd.sbi) + nilfs_put_sbinfo(sd.sbi); + + if (IS_ERR(s)) { + err = PTR_ERR(s); + goto failed_unlock; } if (!s->s_root) { char b[BDEVNAME_SIZE]; + /* New superblock instance created */ s->s_flags = flags; strlcpy(s->s_id, bdevname(sd.bdev, b), sizeof(s->s_id)); sb_set_blocksize(s, block_size(sd.bdev)); @@ -1172,26 +1162,18 @@ nilfs_get_sb(struct file_system_type *fs_type, int flags, s->s_flags |= MS_ACTIVE; need_to_close = 0; - } else if (!(s->s_flags & MS_RDONLY)) { - err = -EBUSY; } - up(&sd.bdev->bd_mount_sem); + mutex_unlock(&nilfs->ns_mount_mutex); put_nilfs(nilfs); if (need_to_close) close_bdev_exclusive(sd.bdev, flags); simple_set_mnt(mnt, s); return 0; - error_s: - up(&sd.bdev->bd_mount_sem); - if (nilfs) - put_nilfs(nilfs); - close_bdev_exclusive(sd.bdev, flags); - return PTR_ERR(s); - failed_unlock: - up(&sd.bdev->bd_mount_sem); + mutex_unlock(&nilfs->ns_mount_mutex); + put_nilfs(nilfs); failed: close_bdev_exclusive(sd.bdev, flags); @@ -1199,70 +1181,18 @@ nilfs_get_sb(struct file_system_type *fs_type, int flags, cancel_new: /* Abandoning the newly allocated superblock */ - up(&sd.bdev->bd_mount_sem); - if (nilfs) - put_nilfs(nilfs); + mutex_unlock(&nilfs->ns_mount_mutex); + put_nilfs(nilfs); up_write(&s->s_umount); deactivate_super(s); /* * deactivate_super() invokes close_bdev_exclusive(). * We must finish all post-cleaning before this call; - * put_nilfs() and unlocking bd_mount_sem need the block device. + * put_nilfs() needs the block device. */ return err; } -static int nilfs_test_bdev_super3(struct super_block *s, void *data) -{ - struct nilfs_super_data *sd = data; - int ret; - - if (s->s_bdev != sd->bdev) - return 0; - if (down_read_trylock(&s->s_umount)) { - ret = (s->s_flags & MS_RDONLY) && s->s_root && - nilfs_test_opt(NILFS_SB(s), SNAPSHOT); - up_read(&s->s_umount); - if (ret) - return 0; /* ignore snapshot mounts */ - } - return !((sd->flags ^ s->s_flags) & MS_RDONLY); -} - -static int __false_bdev_super(struct super_block *s, void *data) -{ -#if 0 /* XXX: workaround for lock debug. This is not good idea */ - up_write(&s->s_umount); -#endif - return -EFAULT; -} - -/** - * test_exclusive_mount - check whether an exclusive RW/RO mount exists or not. - * fs_type: filesystem type - * bdev: block device - * flag: 0 (check rw-mount) or MS_RDONLY (check ro-mount) - * res: pointer to an integer to store result - * - * This function must be called within a section protected by bd_mount_mutex. - */ -static int test_exclusive_mount(struct file_system_type *fs_type, - struct block_device *bdev, int flags) -{ - struct super_block *s; - struct nilfs_super_data sd = { .flags = flags, .bdev = bdev }; - - s = sget(fs_type, nilfs_test_bdev_super3, __false_bdev_super, &sd); - if (IS_ERR(s)) { - if (PTR_ERR(s) != -EFAULT) - return PTR_ERR(s); - return 0; /* Not found */ - } - up_write(&s->s_umount); - deactivate_super(s); - return 1; /* Found */ -} - struct file_system_type nilfs_fs_type = { .owner = THIS_MODULE, .name = "nilfs2", diff --git a/fs/nilfs2/the_nilfs.c b/fs/nilfs2/the_nilfs.c index a91f15b8673..e4e5c78bcc9 100644 --- a/fs/nilfs2/the_nilfs.c +++ b/fs/nilfs2/the_nilfs.c @@ -35,6 +35,10 @@ #include "seglist.h" #include "segbuf.h" + +static LIST_HEAD(nilfs_objects); +static DEFINE_SPINLOCK(nilfs_lock); + void nilfs_set_last_segment(struct the_nilfs *nilfs, sector_t start_blocknr, u64 seq, __u64 cno) { @@ -55,7 +59,7 @@ void nilfs_set_last_segment(struct the_nilfs *nilfs, * Return Value: On success, pointer to the_nilfs is returned. * On error, NULL is returned. */ -struct the_nilfs *alloc_nilfs(struct block_device *bdev) +static struct the_nilfs *alloc_nilfs(struct block_device *bdev) { struct the_nilfs *nilfs; @@ -68,7 +72,10 @@ struct the_nilfs *alloc_nilfs(struct block_device *bdev) atomic_set(&nilfs->ns_writer_refcount, -1); atomic_set(&nilfs->ns_ndirtyblks, 0); init_rwsem(&nilfs->ns_sem); + init_rwsem(&nilfs->ns_super_sem); + mutex_init(&nilfs->ns_mount_mutex); mutex_init(&nilfs->ns_writer_mutex); + INIT_LIST_HEAD(&nilfs->ns_list); INIT_LIST_HEAD(&nilfs->ns_supers); spin_lock_init(&nilfs->ns_last_segment_lock); nilfs->ns_gc_inodes_h = NULL; @@ -78,6 +85,45 @@ struct the_nilfs *alloc_nilfs(struct block_device *bdev) } /** + * find_or_create_nilfs - find or create nilfs object + * @bdev: block device to which the_nilfs is related + * + * find_nilfs() looks up an existent nilfs object created on the + * device and gets the reference count of the object. If no nilfs object + * is found on the device, a new nilfs object is allocated. + * + * Return Value: On success, pointer to the nilfs object is returned. + * On error, NULL is returned. + */ +struct the_nilfs *find_or_create_nilfs(struct block_device *bdev) +{ + struct the_nilfs *nilfs, *new = NULL; + + retry: + spin_lock(&nilfs_lock); + list_for_each_entry(nilfs, &nilfs_objects, ns_list) { + if (nilfs->ns_bdev == bdev) { + get_nilfs(nilfs); + spin_unlock(&nilfs_lock); + if (new) + put_nilfs(new); + return nilfs; /* existing object */ + } + } + if (new) { + list_add_tail(&new->ns_list, &nilfs_objects); + spin_unlock(&nilfs_lock); + return new; /* new object */ + } + spin_unlock(&nilfs_lock); + + new = alloc_nilfs(bdev); + if (new) + goto retry; + return NULL; /* insufficient memory */ +} + +/** * put_nilfs - release a reference to the_nilfs * @nilfs: the_nilfs structure to be released * @@ -86,13 +132,20 @@ struct the_nilfs *alloc_nilfs(struct block_device *bdev) */ void put_nilfs(struct the_nilfs *nilfs) { - if (!atomic_dec_and_test(&nilfs->ns_count)) + spin_lock(&nilfs_lock); + if (!atomic_dec_and_test(&nilfs->ns_count)) { + spin_unlock(&nilfs_lock); return; + } + list_del_init(&nilfs->ns_list); + spin_unlock(&nilfs_lock); + /* - * Increment of ns_count never occur below because the caller + * Increment of ns_count never occurs below because the caller * of get_nilfs() holds at least one reference to the_nilfs. * Thus its exclusion control is not required here. */ + might_sleep(); if (nilfs_loaded(nilfs)) { nilfs_mdt_clear(nilfs->ns_sufile); @@ -613,13 +666,63 @@ int nilfs_near_disk_full(struct the_nilfs *nilfs) return ret; } +/** + * nilfs_find_sbinfo - find existing nilfs_sb_info structure + * @nilfs: nilfs object + * @rw_mount: mount type (non-zero value for read/write mount) + * @cno: checkpoint number (zero for read-only mount) + * + * nilfs_find_sbinfo() returns the nilfs_sb_info structure which + * @rw_mount and @cno (in case of snapshots) matched. If no instance + * was found, NULL is returned. Although the super block instance can + * be unmounted after this function returns, the nilfs_sb_info struct + * is kept on memory until nilfs_put_sbinfo() is called. + */ +struct nilfs_sb_info *nilfs_find_sbinfo(struct the_nilfs *nilfs, + int rw_mount, __u64 cno) +{ + struct nilfs_sb_info *sbi; + + down_read(&nilfs->ns_super_sem); + /* + * The SNAPSHOT flag and sb->s_flags are supposed to be + * protected with nilfs->ns_super_sem. + */ + sbi = nilfs->ns_current; + if (rw_mount) { + if (sbi && !(sbi->s_super->s_flags & MS_RDONLY)) + goto found; /* read/write mount */ + else + goto out; + } else if (cno == 0) { + if (sbi && (sbi->s_super->s_flags & MS_RDONLY)) + goto found; /* read-only mount */ + else + goto out; + } + + list_for_each_entry(sbi, &nilfs->ns_supers, s_list) { + if (nilfs_test_opt(sbi, SNAPSHOT) && + sbi->s_snapshot_cno == cno) + goto found; /* snapshot mount */ + } + out: + up_read(&nilfs->ns_super_sem); + return NULL; + + found: + atomic_inc(&sbi->s_count); + up_read(&nilfs->ns_super_sem); + return sbi; +} + int nilfs_checkpoint_is_mounted(struct the_nilfs *nilfs, __u64 cno, int snapshot_mount) { struct nilfs_sb_info *sbi; int ret = 0; - down_read(&nilfs->ns_sem); + down_read(&nilfs->ns_super_sem); if (cno == 0 || cno > nilfs->ns_cno) goto out_unlock; @@ -636,6 +739,6 @@ int nilfs_checkpoint_is_mounted(struct the_nilfs *nilfs, __u64 cno, ret++; out_unlock: - up_read(&nilfs->ns_sem); + up_read(&nilfs->ns_super_sem); return ret; } diff --git a/fs/nilfs2/the_nilfs.h b/fs/nilfs2/the_nilfs.h index 30fe58778d0..e8adbffc626 100644 --- a/fs/nilfs2/the_nilfs.h +++ b/fs/nilfs2/the_nilfs.h @@ -43,12 +43,16 @@ enum { * struct the_nilfs - struct to supervise multiple nilfs mount points * @ns_flags: flags * @ns_count: reference count + * @ns_list: list head for nilfs_list * @ns_bdev: block device * @ns_bdi: backing dev info * @ns_writer: back pointer to writable nilfs_sb_info * @ns_sem: semaphore for shared states + * @ns_super_sem: semaphore for global operations across super block instances + * @ns_mount_mutex: mutex protecting mount process of nilfs * @ns_writer_mutex: mutex protecting ns_writer attach/detach * @ns_writer_refcount: number of referrers on ns_writer + * @ns_current: back pointer to current mount * @ns_sbh: buffer heads of on-disk super blocks * @ns_sbp: pointers to super block data * @ns_sbwtime: previous write time of super blocks @@ -88,15 +92,24 @@ enum { struct the_nilfs { unsigned long ns_flags; atomic_t ns_count; + struct list_head ns_list; struct block_device *ns_bdev; struct backing_dev_info *ns_bdi; struct nilfs_sb_info *ns_writer; struct rw_semaphore ns_sem; + struct rw_semaphore ns_super_sem; + struct mutex ns_mount_mutex; struct mutex ns_writer_mutex; atomic_t ns_writer_refcount; /* + * components protected by ns_super_sem + */ + struct nilfs_sb_info *ns_current; + struct list_head ns_supers; + + /* * used for * - loading the latest checkpoint exclusively. * - allocating a new full segment. @@ -108,7 +121,6 @@ struct the_nilfs { time_t ns_sbwtime[2]; unsigned ns_sbsize; unsigned ns_mount_state; - struct list_head ns_supers; /* * Following fields are dedicated to a writable FS-instance. @@ -191,11 +203,12 @@ THE_NILFS_FNS(DISCONTINUED, discontinued) #define NILFS_ALTSB_FREQ 60 /* spare superblock */ void nilfs_set_last_segment(struct the_nilfs *, sector_t, u64, __u64); -struct the_nilfs *alloc_nilfs(struct block_device *); +struct the_nilfs *find_or_create_nilfs(struct block_device *); void put_nilfs(struct the_nilfs *); int init_nilfs(struct the_nilfs *, struct nilfs_sb_info *, char *); int load_nilfs(struct the_nilfs *, struct nilfs_sb_info *); int nilfs_count_free_blocks(struct the_nilfs *, sector_t *); +struct nilfs_sb_info *nilfs_find_sbinfo(struct the_nilfs *, int, __u64); int nilfs_checkpoint_is_mounted(struct the_nilfs *, __u64, int); int nilfs_near_disk_full(struct the_nilfs *); void nilfs_fall_back_super_block(struct the_nilfs *); @@ -238,6 +251,12 @@ nilfs_detach_writer(struct the_nilfs *nilfs, struct nilfs_sb_info *sbi) mutex_unlock(&nilfs->ns_writer_mutex); } +static inline void nilfs_put_sbinfo(struct nilfs_sb_info *sbi) +{ + if (!atomic_dec_and_test(&sbi->s_count)) + kfree(sbi); +} + static inline void nilfs_get_segment_range(struct the_nilfs *nilfs, __u64 segnum, sector_t *seg_start, sector_t *seg_end) |