* Format of a leaf node is not specified. Generic iam code accesses leaf
* nodes through ->id_leaf methods in struct iam_descr.
*
+ * The IAM root block is a special node, which contains the IAM descriptor.
+ * It is on disk format:
+ *
+ * +---------+-------+--------+---------+-------+------+-------+------------+
+ * |IAM desc | count | idle | | | | | |
+ * |(fix/var)| / | blocks | padding | entry | .... | entry | free space |
+ * | | limit | | | | | | |
+ * +---------+-------+--------+---------+-------+------+-------+------------+
+ *
+ * The padding length is calculated with the parameters in the IAM descriptor.
+ *
+ * The field "idle_blocks" is used to record empty leaf nodes, which have not
+ * been released but all contained entries in them have been removed. Usually,
+ * the idle blocks in the IAM should be reused when need to allocate new leaf
+ * nodes for new entries, it depends on the IAM hash functions to map the new
+ * entries to these idle blocks. Unfortunately, it is not easy to design some
+ * hash functions for such clever mapping, especially considering the insert/
+ * lookup performance.
+ *
+ * So the IAM recycles the empty leaf nodes, and put them into a per-file based
+ * idle blocks pool. If need some new leaf node, it will try to take idle block
+ * from such pool with priority, in spite of how the IAM hash functions to map
+ * the entry.
+ *
+ * The idle blocks pool is organized as a series of tables, and each table
+ * can be described as following (on-disk format):
+ *
+ * +---------+---------+---------+---------+------+---------+-------+
+ * | magic | count | next | logic | | logic | free |
+ * |(16 bits)|(16 bits)| table | blk # | .... | blk # | space |
+ * | | |(32 bits)|(32 bits)| |(32 bits)| |
+ * +---------+---------+---------+---------+------+---------+-------+
+ *
+ * The logic blk# for the first table is stored in the root node "idle_blocks".
+ *
*/
#include <linux/module.h>
}
EXPORT_SYMBOL(iam_format_register);
+static struct buffer_head *
+iam_load_idle_blocks(struct iam_container *c, iam_ptr_t blk)
+{
+ struct inode *inode = c->ic_object;
+ struct iam_idle_head *head;
+ struct buffer_head *bh;
+ int err;
+
+ LASSERT_SEM_LOCKED(&c->ic_idle_sem);
+
+ if (blk == 0)
+ return NULL;
+
+ bh = ldiskfs_bread(NULL, inode, blk, 0, &err);
+ if (bh == NULL) {
+ CERROR("%.16s: cannot load idle blocks, blk = %u, err = %d\n",
+ LDISKFS_SB(inode->i_sb)->s_es->s_volume_name, blk, err);
+ c->ic_idle_failed = 1;
+ return ERR_PTR(err);
+ }
+
+ head = (struct iam_idle_head *)(bh->b_data);
+ if (le16_to_cpu(head->iih_magic) != IAM_IDLE_HEADER_MAGIC) {
+ CERROR("%.16s: invalid idle block head, blk = %u, magic = %d\n",
+ LDISKFS_SB(inode->i_sb)->s_es->s_volume_name, blk,
+ le16_to_cpu(head->iih_magic));
+ brelse(bh);
+ c->ic_idle_failed = 1;
+ return ERR_PTR(-EBADF);
+ }
+
+ return bh;
+}
+
/*
* Determine format of given container. This is done by scanning list of
* registered formats and calling ->if_guess() method of each in turn.
if (result == 0)
break;
}
- return result;
+
+ if (result == 0) {
+ struct buffer_head *bh;
+ __u32 *idle_blocks;
+
+ LASSERT(c->ic_root_bh != NULL);
+
+ idle_blocks = (__u32 *)(c->ic_root_bh->b_data +
+ c->ic_descr->id_root_gap +
+ sizeof(struct dx_countlimit));
+ cfs_down(&c->ic_idle_sem);
+ bh = iam_load_idle_blocks(c, le32_to_cpu(*idle_blocks));
+ if (bh != NULL && IS_ERR(bh))
+ result = PTR_ERR(bh);
+ else
+ c->ic_idle_bh = bh;
+ cfs_up(&c->ic_idle_sem);
+ }
+
+ return result;
}
/*
* Initialize container @c.
*/
int iam_container_init(struct iam_container *c,
- struct iam_descr *descr, struct inode *inode)
+ struct iam_descr *descr, struct inode *inode)
{
- memset(c, 0, sizeof *c);
- c->ic_descr = descr;
- c->ic_object = inode;
- cfs_init_rwsem(&c->ic_sem);
+ memset(c, 0, sizeof *c);
+ c->ic_descr = descr;
+ c->ic_object = inode;
+ cfs_init_rwsem(&c->ic_sem);
dynlock_init(&c->ic_tree_lock);
- return 0;
+ cfs_sema_init(&c->ic_idle_sem, 1);
+ return 0;
}
EXPORT_SYMBOL(iam_container_init);
*/
void iam_container_fini(struct iam_container *c)
{
- brelse(c->ic_root_bh);
- c->ic_root_bh = NULL;
+ brelse(c->ic_idle_bh);
+ c->ic_idle_bh = NULL;
+ brelse(c->ic_root_bh);
+ c->ic_root_bh = NULL;
}
EXPORT_SYMBOL(iam_container_fini);
iam_leaf_ops(l)->split(l, bh, nr);
}
+static inline int iam_leaf_empty(struct iam_leaf *l)
+{
+ return iam_leaf_ops(l)->leaf_empty(l);
+}
+
int iam_leaf_can_add(const struct iam_leaf *l,
const struct iam_key *k, const struct iam_rec *r)
{
while (1) {
do_corr(schedule());
iam_lock_bh(p->bh);
- p->at = iam_entry_shift(path, p->at, +1);
+ if (p->at_shifted)
+ p->at_shifted = 0;
+ else
+ p->at = iam_entry_shift(path, p->at, +1);
if (p->at < iam_entry_shift(path, p->entries,
dx_get_count(p->entries))) {
p->leaf = dx_get_block(path, p->at);
}
EXPORT_SYMBOL(iam_it_key_size);
+struct buffer_head *
+iam_new_node(handle_t *h, struct iam_container *c, iam_ptr_t *b, int *e)
+{
+ struct inode *inode = c->ic_object;
+ struct buffer_head *bh = NULL;
+ struct iam_idle_head *head;
+ struct buffer_head *idle;
+ __u32 *idle_blocks;
+ __u16 count;
+
+ if (c->ic_idle_bh == NULL)
+ goto newblock;
+
+ cfs_down(&c->ic_idle_sem);
+ if (unlikely(c->ic_idle_failed || c->ic_idle_bh == NULL)) {
+ cfs_up(&c->ic_idle_sem);
+ goto newblock;
+ }
+
+ head = (struct iam_idle_head *)(c->ic_idle_bh->b_data);
+ count = le16_to_cpu(head->iih_count);
+ if (count > 0) {
+ *e = ldiskfs_journal_get_write_access(h, c->ic_idle_bh);
+ if (*e != 0)
+ goto fail;
+
+ --count;
+ *b = le32_to_cpu(head->iih_blks[count]);
+ head->iih_count = cpu_to_le16(count);
+ *e = ldiskfs_journal_dirty_metadata(h, c->ic_idle_bh);
+ if (*e != 0)
+ goto fail;
+
+ cfs_up(&c->ic_idle_sem);
+ bh = ldiskfs_bread(NULL, inode, *b, 0, e);
+ if (bh == NULL)
+ return NULL;
+ goto got;
+ }
+
+ /* The block itself which contains the iam_idle_head is
+ * also an idle block, and can be used as the new node. */
+ idle_blocks = (__u32 *)(c->ic_root_bh->b_data +
+ c->ic_descr->id_root_gap +
+ sizeof(struct dx_countlimit));
+ *e = ldiskfs_journal_get_write_access(h, c->ic_root_bh);
+ if (*e != 0)
+ goto fail;
+
+ *b = le32_to_cpu(*idle_blocks);
+ iam_lock_bh(c->ic_root_bh);
+ *idle_blocks = head->iih_next;
+ iam_unlock_bh(c->ic_root_bh);
+ *e = ldiskfs_journal_dirty_metadata(h, c->ic_root_bh);
+ if (*e != 0) {
+ iam_lock_bh(c->ic_root_bh);
+ *idle_blocks = cpu_to_le32(*b);
+ iam_unlock_bh(c->ic_root_bh);
+ goto fail;
+ }
+
+ bh = c->ic_idle_bh;
+ idle = iam_load_idle_blocks(c, le32_to_cpu(*idle_blocks));
+ if (idle != NULL && IS_ERR(idle)) {
+ *e = PTR_ERR(idle);
+ c->ic_idle_bh = NULL;
+ brelse(bh);
+ goto fail;
+ }
+
+ c->ic_idle_bh = idle;
+ cfs_up(&c->ic_idle_sem);
+
+got:
+ /* get write access for the found buffer head */
+ *e = ldiskfs_journal_get_write_access(h, bh);
+ if (*e != 0) {
+ brelse(bh);
+ bh = NULL;
+ ldiskfs_std_error(inode->i_sb, *e);
+ }
+ return bh;
+
+newblock:
+ bh = ldiskfs_append(h, inode, b, e);
+ return bh;
+
+fail:
+ cfs_up(&c->ic_idle_sem);
+ ldiskfs_std_error(inode->i_sb, *e);
+ return NULL;
+}
+
/*
* Insertion of new record. Interaction with jbd during non-trivial case (when
* split happens) is as following:
*
- * - new leaf node is involved into transaction by ldiskfs_append();
+ * - new leaf node is involved into transaction by iam_new_node();
*
* - old leaf node is involved into transaction by iam_add_rec();
*
path = leaf->il_path;
obj = c->ic_object;
- new_leaf = ldiskfs_append(handle, obj, (__u32 *)&blknr, &err);
+ new_leaf = iam_new_node(handle, c, &blknr, &err);
do_corr(schedule());
if (new_leaf != NULL) {
struct dynlock_handle *lh;
/* Go back down, allocating blocks, locking them, and adding into
* transaction... */
for (frame = safe + 1, i = 0; i < nr_splet; ++i, ++frame) {
- bh_new[i] = ldiskfs_append (handle, dir, &newblock[i], &err);
+ bh_new[i] = iam_new_node(handle, path->ip_container,
+ &newblock[i], &err);
do_corr(schedule());
if (!bh_new[i] ||
descr->id_ops->id_node_init(path->ip_container,
}
EXPORT_SYMBOL(iam_it_rec_insert);
+static inline int iam_idle_blocks_limit(struct inode *inode)
+{
+ return (inode->i_sb->s_blocksize - sizeof(struct iam_idle_head)) >> 2;
+}
+
+/*
+ * If the leaf cannnot be recycled, we will lose one block for reusing.
+ * It is not a serious issue because it almost the same of non-recycle.
+ */
+static iam_ptr_t iam_index_shrink(handle_t *h, struct iam_path *p,
+ struct iam_leaf *l, struct buffer_head **bh)
+{
+ struct iam_container *c = p->ip_container;
+ struct inode *inode = c->ic_object;
+ struct iam_frame *frame = p->ip_frame;
+ struct iam_entry *entries;
+ struct dynlock_handle *lh;
+ int count;
+ int rc;
+
+ if (c->ic_idle_failed)
+ return 0;
+
+ if (unlikely(frame == NULL))
+ return 0;
+
+ if (!iam_leaf_empty(l))
+ return 0;
+
+ lh = iam_lock_htree(c, frame->curidx, DLT_WRITE);
+ if (lh == NULL) {
+ CWARN("%.16s: No memory to recycle idle blocks\n",
+ LDISKFS_SB(inode->i_sb)->s_es->s_volume_name);
+ return 0;
+ }
+
+ rc = iam_txn_add(h, p, frame->bh);
+ if (rc != 0) {
+ iam_unlock_htree(c, lh);
+ return 0;
+ }
+
+ iam_lock_bh(frame->bh);
+ entries = frame->entries;
+ count = dx_get_count(entries);
+ if (frame->at < iam_entry_shift(p, entries, count - 1)) {
+ struct iam_entry *n = iam_entry_shift(p, frame->at, 1);
+
+ memmove(frame->at, n,
+ (char *)iam_entry_shift(p, entries, count) - (char *)n);
+ frame->at_shifted = 1;
+ }
+ dx_set_count(entries, count - 1);
+ rc = iam_txn_dirty(h, p, frame->bh);
+ iam_unlock_bh(frame->bh);
+ iam_unlock_htree(c, lh);
+ if (rc != 0)
+ return 0;
+
+ get_bh(l->il_bh);
+ *bh = l->il_bh;
+ return frame->leaf;
+}
+
+static int
+iam_install_idle_blocks(handle_t *h, struct iam_path *p, struct buffer_head *bh,
+ __u32 *idle_blocks, iam_ptr_t blk)
+{
+ struct iam_container *c = p->ip_container;
+ struct buffer_head *old = c->ic_idle_bh;
+ struct iam_idle_head *head;
+ int rc;
+
+ rc = iam_txn_add(h, p, bh);
+ if (rc != 0)
+ return rc;
+
+ head = (struct iam_idle_head *)(bh->b_data);
+ head->iih_magic = cpu_to_le16(IAM_IDLE_HEADER_MAGIC);
+ head->iih_count = 0;
+ head->iih_next = *idle_blocks;
+ rc = iam_txn_dirty(h, p, bh);
+ if (rc != 0)
+ return rc;
+
+ rc = iam_txn_add(h, p, c->ic_root_bh);
+ if (rc != 0)
+ return rc;
+
+ iam_lock_bh(c->ic_root_bh);
+ *idle_blocks = cpu_to_le32(blk);
+ iam_unlock_bh(c->ic_root_bh);
+ rc = iam_txn_dirty(h, p, c->ic_root_bh);
+ if (rc == 0) {
+ /* NOT release old before new assigned. */
+ get_bh(bh);
+ c->ic_idle_bh = bh;
+ brelse(old);
+ } else {
+ iam_lock_bh(c->ic_root_bh);
+ *idle_blocks = head->iih_next;
+ iam_unlock_bh(c->ic_root_bh);
+ }
+ return rc;
+}
+
+/*
+ * If the leaf cannnot be recycled, we will lose one block for reusing.
+ * It is not a serious issue because it almost the same of non-recycle.
+ */
+static void iam_recycle_leaf(handle_t *h, struct iam_path *p,
+ struct buffer_head *bh, iam_ptr_t blk)
+{
+ struct iam_container *c = p->ip_container;
+ struct inode *inode = c->ic_object;
+ struct iam_idle_head *head;
+ __u32 *idle_blocks;
+ int count;
+ int rc;
+
+ cfs_down(&c->ic_idle_sem);
+ if (unlikely(c->ic_idle_failed)) {
+ rc = -EFAULT;
+ goto unlock;
+ }
+
+ idle_blocks = (__u32 *)(c->ic_root_bh->b_data +
+ c->ic_descr->id_root_gap +
+ sizeof(struct dx_countlimit));
+ /* It is the first idle block. */
+ if (c->ic_idle_bh == NULL) {
+ rc = iam_install_idle_blocks(h, p, bh, idle_blocks, blk);
+ goto unlock;
+ }
+
+ head = (struct iam_idle_head *)(c->ic_idle_bh->b_data);
+ count = le16_to_cpu(head->iih_count);
+ /* Current ic_idle_bh is full, to be replaced by the leaf. */
+ if (count == iam_idle_blocks_limit(inode)) {
+ rc = iam_install_idle_blocks(h, p, bh, idle_blocks, blk);
+ goto unlock;
+ }
+
+ /* Just add to ic_idle_bh. */
+ rc = iam_txn_add(h, p, c->ic_idle_bh);
+ if (rc != 0)
+ goto unlock;
+
+ head->iih_blks[count] = cpu_to_le32(blk);
+ head->iih_count = cpu_to_le16(count + 1);
+ rc = iam_txn_dirty(h, p, c->ic_idle_bh);
+
+unlock:
+ cfs_up(&c->ic_idle_sem);
+ if (rc != 0)
+ CWARN("%.16s: idle blocks failed, will lose the blk %u\n",
+ LDISKFS_SB(inode->i_sb)->s_es->s_volume_name, blk);
+}
+
/*
* Delete record under iterator.
*
if (result == 0) {
iam_rec_del(leaf, it->ii_flags&IAM_IT_MOVE);
result = iam_txn_dirty(h, path, leaf->il_bh);
- if (result == 0 && iam_leaf_at_end(leaf) &&
- it->ii_flags&IAM_IT_MOVE) {
- result = iam_it_next(it);
- if (result > 0)
- result = 0;
- }
+ if (result == 0 && iam_leaf_at_end(leaf)) {
+ struct buffer_head *bh = NULL;
+ iam_ptr_t blk;
+
+ blk = iam_index_shrink(h, path, leaf, &bh);
+ if (it->ii_flags & IAM_IT_MOVE) {
+ result = iam_it_next(it);
+ if (result > 0)
+ result = 0;
+ }
+
+ if (bh != NULL) {
+ iam_recycle_leaf(h, path, bh, blk);
+ brelse(bh);
+ }
+ }
}
assert_inv(iam_leaf_check(leaf));
assert_inv(iam_path_check(path));
git://git.whamcloud.com / fs / lustre-release.git / commitdiff