spin_lock_init(&root->list_lock);
mutex_init(&root->objectid_mutex);
mutex_init(&root->log_mutex);
+ init_waitqueue_head(&root->log_writer_wait);
+ init_waitqueue_head(&root->log_commit_wait[0]);
+ init_waitqueue_head(&root->log_commit_wait[1]);
+ atomic_set(&root->log_commit[0], 0);
+ atomic_set(&root->log_commit[1], 0);
+ atomic_set(&root->log_writers, 0);
+ root->log_batch = 0;
+ root->log_transid = 0;
extent_io_tree_init(&root->dirty_log_pages,
fs_info->btree_inode->i_mapping, GFP_NOFS);
return 0;
}
-int btrfs_init_log_root_tree(struct btrfs_trans_handle *trans,
- struct btrfs_fs_info *fs_info)
+static struct btrfs_root *alloc_log_tree(struct btrfs_trans_handle *trans,
+ struct btrfs_fs_info *fs_info)
{
struct btrfs_root *root;
struct btrfs_root *tree_root = fs_info->tree_root;
+ struct extent_buffer *leaf;
root = kzalloc(sizeof(*root), GFP_NOFS);
if (!root)
- return -ENOMEM;
+ return ERR_PTR(-ENOMEM);
__setup_root(tree_root->nodesize, tree_root->leafsize,
tree_root->sectorsize, tree_root->stripesize,
root->root_key.objectid = BTRFS_TREE_LOG_OBJECTID;
root->root_key.type = BTRFS_ROOT_ITEM_KEY;
root->root_key.offset = BTRFS_TREE_LOG_OBJECTID;
+ /*
+ * log trees do not get reference counted because they go away
+ * before a real commit is actually done. They do store pointers
+ * to file data extents, and those reference counts still get
+ * updated (along with back refs to the log tree).
+ */
root->ref_cows = 0;
- root->node = btrfs_alloc_free_block(trans, root, root->leafsize,
- 0, BTRFS_TREE_LOG_OBJECTID,
- trans->transid, 0, 0, 0);
+ leaf = btrfs_alloc_free_block(trans, root, root->leafsize,
+ 0, BTRFS_TREE_LOG_OBJECTID,
+ trans->transid, 0, 0, 0);
+ if (IS_ERR(leaf)) {
+ kfree(root);
+ return ERR_CAST(leaf);
+ }
+ root->node = leaf;
btrfs_set_header_nritems(root->node, 0);
btrfs_set_header_level(root->node, 0);
btrfs_set_header_bytenr(root->node, root->node->start);
BTRFS_FSID_SIZE);
btrfs_mark_buffer_dirty(root->node);
btrfs_tree_unlock(root->node);
- fs_info->log_root_tree = root;
+ return root;
+}
+
+int btrfs_init_log_root_tree(struct btrfs_trans_handle *trans,
+ struct btrfs_fs_info *fs_info)
+{
+ struct btrfs_root *log_root;
+
+ log_root = alloc_log_tree(trans, fs_info);
+ if (IS_ERR(log_root))
+ return PTR_ERR(log_root);
+ WARN_ON(fs_info->log_root_tree);
+ fs_info->log_root_tree = log_root;
+ return 0;
+}
+
+int btrfs_add_log_tree(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root)
+{
+ struct btrfs_root *log_root;
+ struct btrfs_inode_item *inode_item;
+
+ log_root = alloc_log_tree(trans, root->fs_info);
+ if (IS_ERR(log_root))
+ return PTR_ERR(log_root);
+
+ log_root->last_trans = trans->transid;
+ log_root->root_key.offset = root->root_key.objectid;
+
+ inode_item = &log_root->root_item.inode;
+ inode_item->generation = cpu_to_le64(1);
+ inode_item->size = cpu_to_le64(3);
+ inode_item->nlink = cpu_to_le32(1);
+ inode_item->nbytes = cpu_to_le64(root->leafsize);
+ inode_item->mode = cpu_to_le32(S_IFDIR | 0755);
+
+ btrfs_set_root_bytenr(&log_root->root_item, log_root->node->start);
+ btrfs_set_root_generation(&log_root->root_item, trans->transid);
+
+ WARN_ON(root->log_root);
+ root->log_root = log_root;
+ root->log_transid = 0;
return 0;
}
init_waitqueue_head(&fs_info->transaction_throttle);
init_waitqueue_head(&fs_info->transaction_wait);
init_waitqueue_head(&fs_info->async_submit_wait);
- init_waitqueue_head(&fs_info->tree_log_wait);
- atomic_set(&fs_info->tree_log_commit, 0);
- atomic_set(&fs_info->tree_log_writers, 0);
- fs_info->tree_log_transid = 0;
__setup_root(4096, 4096, 4096, 4096, tree_root,
fs_info, BTRFS_ROOT_TREE_OBJECTID);
*/
/*
- * btrfs_add_log_tree adds a new per-subvolume log tree into the
- * tree of log tree roots. This must be called with a tree log transaction
- * running (see start_log_trans).
- */
-static int btrfs_add_log_tree(struct btrfs_trans_handle *trans,
- struct btrfs_root *root)
-{
- struct btrfs_key key;
- struct btrfs_root_item root_item;
- struct btrfs_inode_item *inode_item;
- struct extent_buffer *leaf;
- struct btrfs_root *new_root = root;
- int ret;
- u64 objectid = root->root_key.objectid;
-
- leaf = btrfs_alloc_free_block(trans, root, root->leafsize, 0,
- BTRFS_TREE_LOG_OBJECTID,
- trans->transid, 0, 0, 0);
- if (IS_ERR(leaf)) {
- ret = PTR_ERR(leaf);
- return ret;
- }
-
- btrfs_set_header_nritems(leaf, 0);
- btrfs_set_header_level(leaf, 0);
- btrfs_set_header_bytenr(leaf, leaf->start);
- btrfs_set_header_generation(leaf, trans->transid);
- btrfs_set_header_owner(leaf, BTRFS_TREE_LOG_OBJECTID);
-
- write_extent_buffer(leaf, root->fs_info->fsid,
- (unsigned long)btrfs_header_fsid(leaf),
- BTRFS_FSID_SIZE);
- btrfs_mark_buffer_dirty(leaf);
-
- inode_item = &root_item.inode;
- memset(inode_item, 0, sizeof(*inode_item));
- inode_item->generation = cpu_to_le64(1);
- inode_item->size = cpu_to_le64(3);
- inode_item->nlink = cpu_to_le32(1);
- inode_item->nbytes = cpu_to_le64(root->leafsize);
- inode_item->mode = cpu_to_le32(S_IFDIR | 0755);
-
- btrfs_set_root_bytenr(&root_item, leaf->start);
- btrfs_set_root_generation(&root_item, trans->transid);
- btrfs_set_root_level(&root_item, 0);
- btrfs_set_root_refs(&root_item, 0);
- btrfs_set_root_used(&root_item, 0);
-
- memset(&root_item.drop_progress, 0, sizeof(root_item.drop_progress));
- root_item.drop_level = 0;
-
- btrfs_tree_unlock(leaf);
- free_extent_buffer(leaf);
- leaf = NULL;
-
- btrfs_set_root_dirid(&root_item, 0);
-
- key.objectid = BTRFS_TREE_LOG_OBJECTID;
- key.offset = objectid;
- btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY);
- ret = btrfs_insert_root(trans, root->fs_info->log_root_tree, &key,
- &root_item);
- if (ret)
- goto fail;
-
- new_root = btrfs_read_fs_root_no_radix(root->fs_info->log_root_tree,
- &key);
- BUG_ON(!new_root);
-
- WARN_ON(root->log_root);
- root->log_root = new_root;
-
- /*
- * log trees do not get reference counted because they go away
- * before a real commit is actually done. They do store pointers
- * to file data extents, and those reference counts still get
- * updated (along with back refs to the log tree).
- */
- new_root->ref_cows = 0;
- new_root->last_trans = trans->transid;
-
- /*
- * we need to make sure the root block for this new tree
- * is marked as dirty in the dirty_log_pages tree. This
- * is how it gets flushed down to disk at tree log commit time.
- *
- * the tree logging mutex keeps others from coming in and changing
- * the new_root->node, so we can safely access it here
- */
- set_extent_dirty(&new_root->dirty_log_pages, new_root->node->start,
- new_root->node->start + new_root->node->len - 1,
- GFP_NOFS);
-
-fail:
- return ret;
-}
-
-/*
* start a sub transaction and setup the log tree
* this increments the log tree writer count to make the people
* syncing the tree wait for us to finish
struct btrfs_root *root)
{
int ret;
+
+ mutex_lock(&root->log_mutex);
+ if (root->log_root) {
+ root->log_batch++;
+ atomic_inc(&root->log_writers);
+ mutex_unlock(&root->log_mutex);
+ return 0;
+ }
mutex_lock(&root->fs_info->tree_log_mutex);
if (!root->fs_info->log_root_tree) {
ret = btrfs_init_log_root_tree(trans, root->fs_info);
ret = btrfs_add_log_tree(trans, root);
BUG_ON(ret);
}
- atomic_inc(&root->fs_info->tree_log_writers);
- root->fs_info->tree_log_batch++;
mutex_unlock(&root->fs_info->tree_log_mutex);
+ root->log_batch++;
+ atomic_inc(&root->log_writers);
+ mutex_unlock(&root->log_mutex);
return 0;
}
if (!root->log_root)
return -ENOENT;
- mutex_lock(&root->fs_info->tree_log_mutex);
+ mutex_lock(&root->log_mutex);
if (root->log_root) {
ret = 0;
- atomic_inc(&root->fs_info->tree_log_writers);
- root->fs_info->tree_log_batch++;
+ atomic_inc(&root->log_writers);
}
- mutex_unlock(&root->fs_info->tree_log_mutex);
+ mutex_unlock(&root->log_mutex);
return ret;
}
*/
static int end_log_trans(struct btrfs_root *root)
{
- atomic_dec(&root->fs_info->tree_log_writers);
- smp_mb();
- if (waitqueue_active(&root->fs_info->tree_log_wait))
- wake_up(&root->fs_info->tree_log_wait);
+ if (atomic_dec_and_test(&root->log_writers)) {
+ smp_mb();
+ if (waitqueue_active(&root->log_writer_wait))
+ wake_up(&root->log_writer_wait);
+ }
return 0;
}
}
}
btrfs_free_path(path);
- if (wc->free)
- free_extent_buffer(log->node);
return ret;
}
-static int wait_log_commit(struct btrfs_root *log)
+/*
+ * helper function to update the item for a given subvolumes log root
+ * in the tree of log roots
+ */
+static int update_log_root(struct btrfs_trans_handle *trans,
+ struct btrfs_root *log)
+{
+ int ret;
+
+ if (log->log_transid == 1) {
+ /* insert root item on the first sync */
+ ret = btrfs_insert_root(trans, log->fs_info->log_root_tree,
+ &log->root_key, &log->root_item);
+ } else {
+ ret = btrfs_update_root(trans, log->fs_info->log_root_tree,
+ &log->root_key, &log->root_item);
+ }
+ return ret;
+}
+
+static int wait_log_commit(struct btrfs_root *root, unsigned long transid)
{
DEFINE_WAIT(wait);
- u64 transid = log->fs_info->tree_log_transid;
+ int index = transid % 2;
+ /*
+ * we only allow two pending log transactions at a time,
+ * so we know that if ours is more than 2 older than the
+ * current transaction, we're done
+ */
do {
- prepare_to_wait(&log->fs_info->tree_log_wait, &wait,
- TASK_UNINTERRUPTIBLE);
- mutex_unlock(&log->fs_info->tree_log_mutex);
- if (atomic_read(&log->fs_info->tree_log_commit))
+ prepare_to_wait(&root->log_commit_wait[index],
+ &wait, TASK_UNINTERRUPTIBLE);
+ mutex_unlock(&root->log_mutex);
+ if (root->log_transid < transid + 2 &&
+ atomic_read(&root->log_commit[index]))
schedule();
- finish_wait(&log->fs_info->tree_log_wait, &wait);
- mutex_lock(&log->fs_info->tree_log_mutex);
- } while (transid == log->fs_info->tree_log_transid &&
- atomic_read(&log->fs_info->tree_log_commit));
+ finish_wait(&root->log_commit_wait[index], &wait);
+ mutex_lock(&root->log_mutex);
+ } while (root->log_transid < transid + 2 &&
+ atomic_read(&root->log_commit[index]));
+ return 0;
+}
+
+static int wait_for_writer(struct btrfs_root *root)
+{
+ DEFINE_WAIT(wait);
+ while (atomic_read(&root->log_writers)) {
+ prepare_to_wait(&root->log_writer_wait,
+ &wait, TASK_UNINTERRUPTIBLE);
+ mutex_unlock(&root->log_mutex);
+ if (atomic_read(&root->log_writers))
+ schedule();
+ mutex_lock(&root->log_mutex);
+ finish_wait(&root->log_writer_wait, &wait);
+ }
return 0;
}
int btrfs_sync_log(struct btrfs_trans_handle *trans,
struct btrfs_root *root)
{
+ int index1;
+ int index2;
int ret;
- unsigned long batch;
struct btrfs_root *log = root->log_root;
+ struct btrfs_root *log_root_tree = root->fs_info->log_root_tree;
- mutex_lock(&log->fs_info->tree_log_mutex);
- if (atomic_read(&log->fs_info->tree_log_commit)) {
- wait_log_commit(log);
- goto out;
+ mutex_lock(&root->log_mutex);
+ index1 = root->log_transid % 2;
+ if (atomic_read(&root->log_commit[index1])) {
+ wait_log_commit(root, root->log_transid);
+ mutex_unlock(&root->log_mutex);
+ return 0;
}
- atomic_set(&log->fs_info->tree_log_commit, 1);
+ atomic_set(&root->log_commit[index1], 1);
+
+ /* wait for previous tree log sync to complete */
+ if (atomic_read(&root->log_commit[(index1 + 1) % 2]))
+ wait_log_commit(root, root->log_transid - 1);
while (1) {
- batch = log->fs_info->tree_log_batch;
- mutex_unlock(&log->fs_info->tree_log_mutex);
+ unsigned long batch = root->log_batch;
+ mutex_unlock(&root->log_mutex);
schedule_timeout_uninterruptible(1);
- mutex_lock(&log->fs_info->tree_log_mutex);
-
- while (atomic_read(&log->fs_info->tree_log_writers)) {
- DEFINE_WAIT(wait);
- prepare_to_wait(&log->fs_info->tree_log_wait, &wait,
- TASK_UNINTERRUPTIBLE);
- mutex_unlock(&log->fs_info->tree_log_mutex);
- if (atomic_read(&log->fs_info->tree_log_writers))
- schedule();
- mutex_lock(&log->fs_info->tree_log_mutex);
- finish_wait(&log->fs_info->tree_log_wait, &wait);
- }
- if (batch == log->fs_info->tree_log_batch)
+ mutex_lock(&root->log_mutex);
+ wait_for_writer(root);
+ if (batch == root->log_batch)
break;
}
ret = btrfs_write_and_wait_marked_extents(log, &log->dirty_log_pages);
BUG_ON(ret);
- ret = btrfs_write_and_wait_marked_extents(root->fs_info->log_root_tree,
- &root->fs_info->log_root_tree->dirty_log_pages);
+
+ btrfs_set_root_bytenr(&log->root_item, log->node->start);
+ btrfs_set_root_generation(&log->root_item, trans->transid);
+ btrfs_set_root_level(&log->root_item, btrfs_header_level(log->node));
+
+ root->log_batch = 0;
+ root->log_transid++;
+ log->log_transid = root->log_transid;
+ smp_mb();
+ /*
+ * log tree has been flushed to disk, new modifications of
+ * the log will be written to new positions. so it's safe to
+ * allow log writers to go in.
+ */
+ mutex_unlock(&root->log_mutex);
+
+ mutex_lock(&log_root_tree->log_mutex);
+ log_root_tree->log_batch++;
+ atomic_inc(&log_root_tree->log_writers);
+ mutex_unlock(&log_root_tree->log_mutex);
+
+ ret = update_log_root(trans, log);
+ BUG_ON(ret);
+
+ mutex_lock(&log_root_tree->log_mutex);
+ if (atomic_dec_and_test(&log_root_tree->log_writers)) {
+ smp_mb();
+ if (waitqueue_active(&log_root_tree->log_writer_wait))
+ wake_up(&log_root_tree->log_writer_wait);
+ }
+
+ index2 = log_root_tree->log_transid % 2;
+ if (atomic_read(&log_root_tree->log_commit[index2])) {
+ wait_log_commit(log_root_tree, log_root_tree->log_transid);
+ mutex_unlock(&log_root_tree->log_mutex);
+ goto out;
+ }
+ atomic_set(&log_root_tree->log_commit[index2], 1);
+
+ if (atomic_read(&log_root_tree->log_commit[(index2 + 1) % 2]))
+ wait_log_commit(log_root_tree, log_root_tree->log_transid - 1);
+
+ wait_for_writer(log_root_tree);
+
+ ret = btrfs_write_and_wait_marked_extents(log_root_tree,
+ &log_root_tree->dirty_log_pages);
BUG_ON(ret);
btrfs_set_super_log_root(&root->fs_info->super_for_commit,
- log->fs_info->log_root_tree->node->start);
+ log_root_tree->node->start);
btrfs_set_super_log_root_level(&root->fs_info->super_for_commit,
- btrfs_header_level(log->fs_info->log_root_tree->node));
+ btrfs_header_level(log_root_tree->node));
+
+ log_root_tree->log_batch = 0;
+ log_root_tree->log_transid++;
+ smp_mb();
+
+ mutex_unlock(&log_root_tree->log_mutex);
+
+ /*
+ * nobody else is going to jump in and write the the ctree
+ * super here because the log_commit atomic below is protecting
+ * us. We must be called with a transaction handle pinning
+ * the running transaction open, so a full commit can't hop
+ * in and cause problems either.
+ */
+ write_ctree_super(trans, root->fs_info->tree_root, 2);
- write_ctree_super(trans, log->fs_info->tree_root, 2);
- log->fs_info->tree_log_transid++;
- log->fs_info->tree_log_batch = 0;
- atomic_set(&log->fs_info->tree_log_commit, 0);
+ atomic_set(&log_root_tree->log_commit[index2], 0);
smp_mb();
- if (waitqueue_active(&log->fs_info->tree_log_wait))
- wake_up(&log->fs_info->tree_log_wait);
+ if (waitqueue_active(&log_root_tree->log_commit_wait[index2]))
+ wake_up(&log_root_tree->log_commit_wait[index2]);
out:
- mutex_unlock(&log->fs_info->tree_log_mutex);
+ atomic_set(&root->log_commit[index1], 0);
+ smp_mb();
+ if (waitqueue_active(&root->log_commit_wait[index1]))
+ wake_up(&root->log_commit_wait[index1]);
return 0;
}
start, end, GFP_NOFS);
}
- log = root->log_root;
- ret = btrfs_del_root(trans, root->fs_info->log_root_tree,
- &log->root_key);
- BUG_ON(ret);
+ if (log->log_transid > 0) {
+ ret = btrfs_del_root(trans, root->fs_info->log_root_tree,
+ &log->root_key);
+ BUG_ON(ret);
+ }
root->log_root = NULL;
- kfree(root->log_root);
+ free_extent_buffer(log->node);
+ kfree(log);
return 0;
}
/*
- * helper function to update the item for a given subvolumes log root
- * in the tree of log roots
- */
-static int update_log_root(struct btrfs_trans_handle *trans,
- struct btrfs_root *log)
-{
- u64 bytenr = btrfs_root_bytenr(&log->root_item);
- int ret;
-
- if (log->node->start == bytenr)
- return 0;
-
- btrfs_set_root_bytenr(&log->root_item, log->node->start);
- btrfs_set_root_generation(&log->root_item, trans->transid);
- btrfs_set_root_level(&log->root_item, btrfs_header_level(log->node));
- ret = btrfs_update_root(trans, log->fs_info->log_root_tree,
- &log->root_key, &log->root_item);
- BUG_ON(ret);
- return ret;
-}
-
-/*
* If both a file and directory are logged, and unlinks or renames are
* mixed in, we have a few interesting corners:
*
btrfs_free_path(path);
btrfs_free_path(dst_path);
-
- mutex_lock(&root->fs_info->tree_log_mutex);
- ret = update_log_root(trans, log);
- BUG_ON(ret);
- mutex_unlock(&root->fs_info->tree_log_mutex);
out:
return 0;
}
git://ftp.safe.ca / safe / jmp / linux-2.6 / commitdiff