diff options
| -rw-r--r-- | fs/nilfs2/sb.h | 1 | ||||
| -rw-r--r-- | fs/nilfs2/super.c | 42 | ||||
| -rw-r--r-- | fs/nilfs2/the_nilfs.c | 50 | ||||
| -rw-r--r-- | fs/nilfs2/the_nilfs.h | 7 |
4 files changed, 75 insertions, 25 deletions
diff --git a/fs/nilfs2/sb.h b/fs/nilfs2/sb.h index adccd4fc654e..0776ccc2504a 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 5a8c5e4731b3..1d1b6e125159 100644 --- a/fs/nilfs2/super.c +++ b/fs/nilfs2/super.c @@ -336,7 +336,7 @@ static void nilfs_put_super(struct super_block *sb) put_nilfs(sbi->s_nilfs); sbi->s_super = NULL; sb->s_fs_info = NULL; - kfree(sbi); + nilfs_put_sbinfo(sbi); unlock_kernel(); } @@ -785,6 +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) @@ -902,7 +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; } @@ -1014,6 +1015,7 @@ static int nilfs_remount(struct super_block *sb, int *flags, char *data) struct nilfs_super_data { struct block_device *bdev; + struct nilfs_sb_info *sbi; __u64 cno; int flags; }; @@ -1071,27 +1073,8 @@ static int nilfs_set_bdev_super(struct super_block *s, void *data) static int nilfs_test_bdev_super(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 @@ -1112,7 +1095,6 @@ 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; @@ -1148,13 +1130,23 @@ nilfs_get_sb(struct file_system_type *fs_type, int flags, } /* - * Search specified snapshot or R/W mode super_block + * Find existing nilfs_sb_info struct */ + sd.sbi = nilfs_find_sbinfo(nilfs, !(flags & MS_RDONLY), sd.cno); + 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; diff --git a/fs/nilfs2/the_nilfs.c b/fs/nilfs2/the_nilfs.c index 45dbf6a61744..221953bfc859 100644 --- a/fs/nilfs2/the_nilfs.c +++ b/fs/nilfs2/the_nilfs.c @@ -664,6 +664,56 @@ 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_sem); + /* + * The SNAPSHOT flag and sb->s_flags are supposed to be + * protected with nilfs->ns_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_sem); + return NULL; + + found: + atomic_inc(&sbi->s_count); + up_read(&nilfs->ns_sem); + return sbi; +} + int nilfs_checkpoint_is_mounted(struct the_nilfs *nilfs, __u64 cno, int snapshot_mount) { diff --git a/fs/nilfs2/the_nilfs.h b/fs/nilfs2/the_nilfs.h index 99f7e29a5335..be4c040fd629 100644 --- a/fs/nilfs2/the_nilfs.h +++ b/fs/nilfs2/the_nilfs.h @@ -201,6 +201,7 @@ 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 *); @@ -243,6 +244,12 @@ 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) |