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author | Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp> | 2010-08-14 05:59:15 +0200 |
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committer | Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp> | 2010-10-23 02:24:34 +0200 |
commit | ba65ae4729bf81c58d9fc847f67d57eec525b042 (patch) | |
tree | 6b2a4499a1e67bf858ce55cfe2e806b24c3697e7 /fs/nilfs2/the_nilfs.c | |
parent | nilfs2: remove own inode hash used for GC (diff) | |
download | linux-ba65ae4729bf81c58d9fc847f67d57eec525b042.tar.xz linux-ba65ae4729bf81c58d9fc847f67d57eec525b042.zip |
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 <konishi.ryusuke@lab.ntt.co.jp>
Diffstat (limited to 'fs/nilfs2/the_nilfs.c')
-rw-r--r-- | fs/nilfs2/the_nilfs.c | 92 |
1 files changed, 92 insertions, 0 deletions
diff --git a/fs/nilfs2/the_nilfs.c b/fs/nilfs2/the_nilfs.c index 6a012b9e1b31..f1d599273d9e 100644 --- a/fs/nilfs2/the_nilfs.c +++ b/fs/nilfs2/the_nilfs.c @@ -89,6 +89,8 @@ static struct the_nilfs *alloc_nilfs(struct block_device *bdev) INIT_LIST_HEAD(&nilfs->ns_supers); INIT_LIST_HEAD(&nilfs->ns_gc_inodes); spin_lock_init(&nilfs->ns_last_segment_lock); + nilfs->ns_cptree = RB_ROOT; + spin_lock_init(&nilfs->ns_cptree_lock); init_rwsem(&nilfs->ns_segctor_sem); return nilfs; @@ -809,6 +811,96 @@ int nilfs_near_disk_full(struct the_nilfs *nilfs) return ncleansegs <= nilfs->ns_nrsvsegs + nincsegs; } +struct nilfs_root *nilfs_lookup_root(struct the_nilfs *nilfs, __u64 cno) +{ + struct rb_node *n; + struct nilfs_root *root; + + spin_lock(&nilfs->ns_cptree_lock); + n = nilfs->ns_cptree.rb_node; + while (n) { + root = rb_entry(n, struct nilfs_root, rb_node); + + if (cno < root->cno) { + n = n->rb_left; + } else if (cno > root->cno) { + n = n->rb_right; + } else { + atomic_inc(&root->count); + spin_unlock(&nilfs->ns_cptree_lock); + return root; + } + } + spin_unlock(&nilfs->ns_cptree_lock); + + return NULL; +} + +struct nilfs_root * +nilfs_find_or_create_root(struct the_nilfs *nilfs, __u64 cno) +{ + struct rb_node **p, *parent; + struct nilfs_root *root, *new; + + root = nilfs_lookup_root(nilfs, cno); + if (root) + return root; + + new = kmalloc(sizeof(*root), GFP_KERNEL); + if (!new) + return NULL; + + spin_lock(&nilfs->ns_cptree_lock); + + p = &nilfs->ns_cptree.rb_node; + parent = NULL; + + while (*p) { + parent = *p; + root = rb_entry(parent, struct nilfs_root, rb_node); + + if (cno < root->cno) { + p = &(*p)->rb_left; + } else if (cno > root->cno) { + p = &(*p)->rb_right; + } else { + atomic_inc(&root->count); + spin_unlock(&nilfs->ns_cptree_lock); + kfree(new); + return root; + } + } + + new->cno = cno; + new->ifile = NULL; + new->nilfs = nilfs; + atomic_set(&new->count, 1); + atomic_set(&new->inodes_count, 0); + atomic_set(&new->blocks_count, 0); + + rb_link_node(&new->rb_node, parent, p); + rb_insert_color(&new->rb_node, &nilfs->ns_cptree); + + spin_unlock(&nilfs->ns_cptree_lock); + + return new; +} + +void nilfs_put_root(struct nilfs_root *root) +{ + if (atomic_dec_and_test(&root->count)) { + struct the_nilfs *nilfs = root->nilfs; + + spin_lock(&nilfs->ns_cptree_lock); + rb_erase(&root->rb_node, &nilfs->ns_cptree); + spin_unlock(&nilfs->ns_cptree_lock); + if (root->ifile) + nilfs_mdt_destroy(root->ifile); + + kfree(root); + } +} + /** * nilfs_find_sbinfo - find existing nilfs_sb_info structure * @nilfs: nilfs object |