[Ocfs2-devel] [PATCH 07/41] ocfs2: Add refcount tree lock mechanism.
Tao Ma
tao.ma at oracle.com
Mon Aug 17 23:19:08 PDT 2009
Create a tree lock named ocfs2_refcount_tree. It protects
all the read/write operation to the refcount tree. Also
it has its only caching_info so that we can protect our
own buffer_head among multiple nodes.
User must call ocfs2_lock_refcount_tree before his operation
on the tree and unlock it after that.
This tree is only indicated by the root refcount block number.
So create a rb-tree for it and store the root in ocfs2_super.
Signed-off-by: Tao Ma <tao.ma at oracle.com>
---
fs/ocfs2/ocfs2.h | 4 +
fs/ocfs2/refcounttree.c | 359 +++++++++++++++++++++++++++++++++++++++++++++++
fs/ocfs2/refcounttree.h | 7 +
fs/ocfs2/super.c | 5 +
4 files changed, 375 insertions(+), 0 deletions(-)
diff --git a/fs/ocfs2/ocfs2.h b/fs/ocfs2/ocfs2.h
index 6688d19..bb53573 100644
--- a/fs/ocfs2/ocfs2.h
+++ b/fs/ocfs2/ocfs2.h
@@ -408,6 +408,10 @@ struct ocfs2_super
/* the group we used to allocate inodes. */
u64 osb_inode_alloc_group;
+
+ /* rb tree root for refcount lock. */
+ struct rb_root osb_rf_lock_tree;
+ struct ocfs2_refcount_tree *osb_ref_tree_lru;
};
#define OCFS2_SB(sb) ((struct ocfs2_super *)(sb)->s_fs_info)
diff --git a/fs/ocfs2/refcounttree.c b/fs/ocfs2/refcounttree.c
index eb0f4a0..b6d356b 100644
--- a/fs/ocfs2/refcounttree.c
+++ b/fs/ocfs2/refcounttree.c
@@ -27,6 +27,7 @@
#include "buffer_head_io.h"
#include "blockcheck.h"
#include "refcounttree.h"
+#include "dlmglue.h"
static inline struct ocfs2_refcount_tree *
cache_info_to_refcount(struct ocfs2_caching_info *ci)
@@ -156,3 +157,361 @@ static const struct ocfs2_caching_operations ocfs2_refcount_caching_ops = {
.co_io_lock = ocfs2_refcount_cache_io_lock,
.co_io_unlock = ocfs2_refcount_cache_io_unlock,
};
+
+static struct ocfs2_refcount_tree *
+ocfs2_find_refcount_tree(struct ocfs2_super *osb, u64 blkno)
+{
+ struct rb_node *n = osb->osb_rf_lock_tree.rb_node;
+ struct ocfs2_refcount_tree *tree = NULL;
+
+ while (n) {
+ tree = rb_entry(n, struct ocfs2_refcount_tree, rf_node);
+
+ if (blkno < tree->rf_blkno)
+ n = n->rb_left;
+ else if (blkno > tree->rf_blkno)
+ n = n->rb_right;
+ else
+ return tree;
+ }
+
+ return NULL;
+}
+
+/* osb_lock is already locked. */
+static void ocfs2_insert_refcount_tree(struct ocfs2_super *osb,
+ struct ocfs2_refcount_tree *new)
+{
+ u64 rf_blkno = new->rf_blkno;
+ struct rb_node *parent = NULL;
+ struct rb_node **p = &osb->osb_rf_lock_tree.rb_node;
+ struct ocfs2_refcount_tree *tmp;
+
+ while (*p) {
+ parent = *p;
+
+ tmp = rb_entry(parent, struct ocfs2_refcount_tree,
+ rf_node);
+
+ if (rf_blkno < tmp->rf_blkno)
+ p = &(*p)->rb_left;
+ else if (rf_blkno > tmp->rf_blkno)
+ p = &(*p)->rb_right;
+ else {
+ /* This should never happen! */
+ mlog(ML_ERROR, "Duplicate refcount block %llu found!\n",
+ (unsigned long long)rf_blkno);
+ BUG();
+ }
+ }
+
+ rb_link_node(&new->rf_node, parent, p);
+ rb_insert_color(&new->rf_node, &osb->osb_rf_lock_tree);
+}
+
+static void ocfs2_free_refcount_tree(struct ocfs2_refcount_tree *tree)
+{
+ ocfs2_metadata_cache_exit(&tree->rf_ci);
+ ocfs2_simple_drop_lockres(OCFS2_SB(tree->rf_sb), &tree->rf_lockres);
+ ocfs2_lock_res_free(&tree->rf_lockres);
+ kfree(tree);
+}
+
+static inline void
+ocfs2_erase_refcount_tree_from_list_no_lock(struct ocfs2_super *osb,
+ struct ocfs2_refcount_tree *tree)
+{
+ rb_erase(&tree->rf_node, &osb->osb_rf_lock_tree);
+ if (osb->osb_ref_tree_lru && osb->osb_ref_tree_lru == tree)
+ osb->osb_ref_tree_lru = NULL;
+}
+
+static void ocfs2_erase_refcount_tree_from_list(struct ocfs2_super *osb,
+ struct ocfs2_refcount_tree *tree)
+{
+ spin_lock(&osb->osb_lock);
+ ocfs2_erase_refcount_tree_from_list_no_lock(osb, tree);
+ spin_unlock(&osb->osb_lock);
+}
+
+void ocfs2_kref_remove_refcount_tree(struct kref *kref)
+{
+ struct ocfs2_refcount_tree *tree =
+ container_of(kref, struct ocfs2_refcount_tree, rf_getcnt);
+
+ ocfs2_free_refcount_tree(tree);
+}
+
+static inline void
+ocfs2_refcount_tree_get(struct ocfs2_refcount_tree *tree)
+{
+ kref_get(&tree->rf_getcnt);
+}
+
+static inline void
+ocfs2_refcount_tree_put(struct ocfs2_refcount_tree *tree)
+{
+ kref_put(&tree->rf_getcnt, ocfs2_kref_remove_refcount_tree);
+}
+
+static inline void ocfs2_init_refcount_tree_ci(struct ocfs2_refcount_tree *new,
+ struct super_block *sb)
+{
+ ocfs2_metadata_cache_init(&new->rf_ci, &ocfs2_refcount_caching_ops);
+ mutex_init(&new->rf_io_mutex);
+ new->rf_sb = sb;
+ spin_lock_init(&new->rf_lock);
+}
+
+static inline void ocfs2_init_refcount_tree_lock(struct ocfs2_super *osb,
+ struct ocfs2_refcount_tree *new,
+ u64 rf_blkno, u32 generation)
+{
+ init_rwsem(&new->rf_sem);
+ ocfs2_refcount_lock_res_init(&new->rf_lockres, osb,
+ rf_blkno, generation);
+}
+
+static int ocfs2_get_refcount_tree(struct ocfs2_super *osb, u64 rf_blkno,
+ struct ocfs2_refcount_tree **ret_tree)
+{
+ int ret = 0;
+ struct ocfs2_refcount_tree *tree, *new = NULL;
+ struct buffer_head *ref_root_bh = NULL;
+ struct ocfs2_refcount_block *ref_rb;
+
+ spin_lock(&osb->osb_lock);
+ if (osb->osb_ref_tree_lru &&
+ osb->osb_ref_tree_lru->rf_blkno == rf_blkno)
+ tree = osb->osb_ref_tree_lru;
+ else
+ tree = ocfs2_find_refcount_tree(osb, rf_blkno);
+ if (tree)
+ goto out;
+
+ spin_unlock(&osb->osb_lock);
+
+ new = kzalloc(sizeof(struct ocfs2_refcount_tree), GFP_NOFS);
+ if (!new) {
+ ret = -ENOMEM;
+ return ret;
+ }
+
+ new->rf_blkno = rf_blkno;
+ kref_init(&new->rf_getcnt);
+ ocfs2_init_refcount_tree_ci(new, osb->sb);
+
+ /*
+ * We need the generation to create the refcount tree lock and since
+ * it isn't changed during the tree modification, we are safe here to
+ * read without protection.
+ * We also have to purge the cache after we create the lock since the
+ * refcount block may have the stale data. It can only be trusted when
+ * we hold the refcount lock.
+ */
+ ret = ocfs2_read_refcount_block(&new->rf_ci, rf_blkno, &ref_root_bh);
+ if (ret) {
+ mlog_errno(ret);
+ ocfs2_metadata_cache_exit(&new->rf_ci);
+ kfree(new);
+ return ret;
+ }
+
+ ref_rb = (struct ocfs2_refcount_block *)ref_root_bh->b_data;
+ new->rf_generation = le32_to_cpu(ref_rb->rf_generation);
+ ocfs2_init_refcount_tree_lock(osb, new, rf_blkno,
+ new->rf_generation);
+ ocfs2_metadata_cache_purge(&new->rf_ci);
+
+ spin_lock(&osb->osb_lock);
+ tree = ocfs2_find_refcount_tree(osb, rf_blkno);
+ if (tree)
+ goto out;
+
+ ocfs2_insert_refcount_tree(osb, new);
+
+ tree = new;
+ new = NULL;
+
+out:
+ *ret_tree = tree;
+
+ osb->osb_ref_tree_lru = tree;
+
+ spin_unlock(&osb->osb_lock);
+
+ if (new)
+ ocfs2_free_refcount_tree(new);
+
+ brelse(ref_root_bh);
+ return ret;
+}
+
+static int ocfs2_get_refcount_block(struct inode *inode, u64 *ref_blkno)
+{
+ int ret;
+ struct buffer_head *di_bh = NULL;
+ struct ocfs2_dinode *di;
+
+ ret = ocfs2_read_inode_block(inode, &di_bh);
+ if (ret) {
+ mlog_errno(ret);
+ goto out;
+ }
+
+ BUG_ON(!(OCFS2_I(inode)->ip_dyn_features & OCFS2_HAS_REFCOUNT_FL));
+
+ di = (struct ocfs2_dinode *)di_bh->b_data;
+ *ref_blkno = le64_to_cpu(di->i_refcount_loc);
+ brelse(di_bh);
+out:
+ return ret;
+}
+
+static int __ocfs2_lock_refcount_tree(struct ocfs2_super *osb,
+ struct ocfs2_refcount_tree *tree, int rw)
+{
+ int ret;
+
+ ret = ocfs2_refcount_lock(tree, rw);
+ if (ret) {
+ mlog_errno(ret);
+ goto out;
+ }
+
+ if (rw)
+ down_write(&tree->rf_sem);
+ else
+ down_read(&tree->rf_sem);
+
+out:
+ return ret;
+}
+
+/*
+ * Lock the refcount tree pointed by ref_blkno and return the tree.
+ * In most case, we lock the tree and read the refcount block.
+ * So read it here if the caller really need it.
+ *
+ * If the tree has been re-created by other node, it will free the
+ * old one and re-create it.
+ */
+int ocfs2_lock_refcount_tree(struct ocfs2_super *osb,
+ u64 ref_blkno, int rw,
+ struct ocfs2_refcount_tree **ret_tree,
+ struct buffer_head **ref_bh)
+{
+ int ret, delete_tree = 0;
+ struct ocfs2_refcount_tree *tree = NULL;
+ struct buffer_head *ref_root_bh = NULL;
+ struct ocfs2_refcount_block *rb;
+
+again:
+ ret = ocfs2_get_refcount_tree(osb, ref_blkno, &tree);
+ if (ret) {
+ mlog_errno(ret);
+ return ret;
+ }
+
+ ocfs2_refcount_tree_get(tree);
+
+ ret = __ocfs2_lock_refcount_tree(osb, tree, rw);
+ if (ret) {
+ mlog_errno(ret);
+ ocfs2_refcount_tree_put(tree);
+ goto out;
+ }
+
+ ret = ocfs2_read_refcount_block(&tree->rf_ci, tree->rf_blkno,
+ &ref_root_bh);
+ if (ret) {
+ mlog_errno(ret);
+ ocfs2_unlock_refcount_tree(osb, tree, rw);
+ ocfs2_refcount_tree_put(tree);
+ goto out;
+ }
+
+ rb = (struct ocfs2_refcount_block *)ref_root_bh->b_data;
+ /*
+ * If the refcount block has been freed and re-created, we may need
+ * to recreate the refcount tree also.
+ *
+ * Here we just remove the tree from the rb-tree, and the last
+ * kref holder will unlock and delete this refcount_tree.
+ * Then we goto "again" and ocfs2_get_refcount_tree will create
+ * the new refcount tree for us.
+ */
+ if (tree->rf_generation != le32_to_cpu(rb->rf_generation)) {
+ if (!tree->rf_removed) {
+ ocfs2_erase_refcount_tree_from_list(osb, tree);
+ tree->rf_removed = 1;
+ delete_tree = 1;
+ }
+
+ ocfs2_unlock_refcount_tree(osb, tree, rw);
+ /*
+ * We get an extra reference when we create the refcount
+ * tree, so another put will destroy it.
+ */
+ if (delete_tree)
+ ocfs2_refcount_tree_put(tree);
+ brelse(ref_root_bh);
+ ref_root_bh = NULL;
+ goto again;
+ }
+
+ *ret_tree = tree;
+ if (ref_bh) {
+ *ref_bh = ref_root_bh;
+ ref_root_bh = NULL;
+ }
+out:
+ brelse(ref_root_bh);
+ return ret;
+}
+
+int ocfs2_lock_refcount_tree_by_inode(struct inode *inode, int rw,
+ struct ocfs2_refcount_tree **ret_tree,
+ struct buffer_head **ref_bh)
+{
+ int ret;
+ u64 ref_blkno;
+
+ ret = ocfs2_get_refcount_block(inode, &ref_blkno);
+ if (ret) {
+ mlog_errno(ret);
+ return ret;
+ }
+
+ return ocfs2_lock_refcount_tree(OCFS2_SB(inode->i_sb), ref_blkno,
+ rw, ret_tree, ref_bh);
+}
+
+void ocfs2_unlock_refcount_tree(struct ocfs2_super *osb,
+ struct ocfs2_refcount_tree *tree, int rw)
+{
+ if (rw)
+ up_write(&tree->rf_sem);
+ else
+ up_read(&tree->rf_sem);
+
+ ocfs2_refcount_unlock(tree, rw);
+ ocfs2_refcount_tree_put(tree);
+}
+
+void ocfs2_purge_refcount_tree(struct ocfs2_super *osb)
+{
+ struct rb_node *node;
+ struct ocfs2_refcount_tree *tree;
+ struct rb_root *root = &osb->osb_rf_lock_tree;
+
+ while ((node = rb_last(root)) != NULL) {
+ tree = rb_entry(node, struct ocfs2_refcount_tree, rf_node);
+
+ mlog(0, "Purge tree %llu\n",
+ (unsigned long long) tree->rf_blkno);
+
+ rb_erase(&tree->rf_node, root);
+ ocfs2_free_refcount_tree(tree);
+ }
+}
diff --git a/fs/ocfs2/refcounttree.h b/fs/ocfs2/refcounttree.h
index 9a3695c..3c38bbd 100644
--- a/fs/ocfs2/refcounttree.h
+++ b/fs/ocfs2/refcounttree.h
@@ -33,4 +33,11 @@ struct ocfs2_refcount_tree {
struct super_block *rf_sb;
};
+void ocfs2_purge_refcount_tree(struct ocfs2_super *osb);
+int ocfs2_lock_refcount_tree(struct ocfs2_super *osb, u64 ref_blkno, int rw,
+ struct ocfs2_refcount_tree **tree,
+ struct buffer_head **ref_bh);
+void ocfs2_unlock_refcount_tree(struct ocfs2_super *osb,
+ struct ocfs2_refcount_tree *tree,
+ int rw);
#endif /* OCFS2_REFCOUNTTREE_H */
diff --git a/fs/ocfs2/super.c b/fs/ocfs2/super.c
index e35a505..4edc298 100644
--- a/fs/ocfs2/super.c
+++ b/fs/ocfs2/super.c
@@ -69,6 +69,7 @@
#include "ver.h"
#include "xattr.h"
#include "quota.h"
+#include "refcounttree.h"
#include "buffer_head_io.h"
@@ -1858,6 +1859,8 @@ static void ocfs2_dismount_volume(struct super_block *sb, int mnt_err)
ocfs2_sync_blockdev(sb);
+ ocfs2_purge_refcount_tree(osb);
+
/* No cluster connection means we've failed during mount, so skip
* all the steps which depended on that to complete. */
if (osb->cconn) {
@@ -2064,6 +2067,8 @@ static int ocfs2_initialize_super(struct super_block *sb,
goto bail;
}
+ osb->osb_rf_lock_tree = RB_ROOT;
+
osb->s_feature_compat =
le32_to_cpu(OCFS2_RAW_SB(di)->s_feature_compat);
osb->s_feature_ro_compat =
--
1.6.2.rc2.16.gf474c
More information about the Ocfs2-devel
mailing list