From ba65ae4729bf81c58d9fc847f67d57eec525b042 Mon Sep 17 00:00:00 2001 From: Ryusuke Konishi Date: Sat, 14 Aug 2010 12:59:15 +0900 Subject: nilfs2: add checkpoint tree to nilfs object To hold multiple versions of a filesystem in one sb instance, a new on-memory structure is necessary to handle one or more checkpoints. This adds a red-black tree of checkpoints to nilfs object, and adds lookup and create functions for them. Each checkpoint is represented by "nilfs_root" structure, and this structure has rb_node to configure the rb-tree. The nilfs_root object is identified with a checkpoint number. For each snapshot, a nilfs_root object is allocated and the checkpoint number of snapshot is assigned to it. For a regular mount (i.e. current mode mount), NILFS_CPTREE_CURRENT_CNO constant is assigned to the corresponding nilfs_root object. Each nilfs_root object has an ifile inode and some counters. These items will displace those of nilfs_sb_info structure in successive patches. Signed-off-by: Ryusuke Konishi --- fs/nilfs2/the_nilfs.h | 42 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 42 insertions(+) (limited to 'fs/nilfs2/the_nilfs.h') diff --git a/fs/nilfs2/the_nilfs.h b/fs/nilfs2/the_nilfs.h index c7ecd0c623a..0afede68a9e 100644 --- a/fs/nilfs2/the_nilfs.h +++ b/fs/nilfs2/the_nilfs.h @@ -26,6 +26,7 @@ #include #include +#include #include #include #include @@ -80,6 +81,8 @@ enum { * @ns_cpfile: checkpoint file inode * @ns_sufile: segusage file inode * @ns_gc_dat: shadow inode of the DAT file inode for GC + * @ns_cptree: rb-tree of all mounted checkpoints (nilfs_root) + * @ns_cptree_lock: lock protecting @ns_cptree * @ns_gc_inodes: dummy inodes to keep live blocks * @ns_blocksize_bits: bit length of block size * @ns_blocksize: block size @@ -164,6 +167,10 @@ struct the_nilfs { struct inode *ns_sufile; struct inode *ns_gc_dat; + /* Checkpoint tree */ + struct rb_root ns_cptree; + spinlock_t ns_cptree_lock; + /* GC inode list */ struct list_head ns_gc_inodes; @@ -200,6 +207,32 @@ THE_NILFS_FNS(DISCONTINUED, discontinued) THE_NILFS_FNS(GC_RUNNING, gc_running) THE_NILFS_FNS(SB_DIRTY, sb_dirty) +/** + * 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 + * @root: root inode + * @inodes_count: number of inodes + * @blocks_count: number of blocks (Reserved) + */ +struct nilfs_root { + __u64 cno; + struct rb_node rb_node; + + atomic_t count; + struct the_nilfs *nilfs; + struct inode *ifile; + + atomic_t inodes_count; + atomic_t blocks_count; +}; + +/* Special checkpoint number */ +#define NILFS_CPTREE_CURRENT_CNO 0 + /* Minimum interval of periodical update of superblocks (in seconds) */ #define NILFS_SB_FREQ 10 @@ -222,6 +255,10 @@ int init_nilfs(struct the_nilfs *, struct nilfs_sb_info *, char *); int load_nilfs(struct the_nilfs *, struct nilfs_sb_info *); 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); 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 *); @@ -235,6 +272,11 @@ static inline void get_nilfs(struct the_nilfs *nilfs) atomic_inc(&nilfs->ns_count); } +static inline void nilfs_get_root(struct nilfs_root *root) +{ + atomic_inc(&root->count); +} + static inline void nilfs_attach_writer(struct the_nilfs *nilfs, struct nilfs_sb_info *sbi) { -- cgit v1.2.3