diff options
Diffstat (limited to 'fs/btrfs/transaction.c')
| -rw-r--r-- | fs/btrfs/transaction.c | 1023 |
1 files changed, 1023 insertions, 0 deletions
diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c new file mode 100644 index 000000000000..5ecc24d634a2 --- /dev/null +++ b/fs/btrfs/transaction.c @@ -0,0 +1,1023 @@ +/* + * Copyright (C) 2007 Oracle. All rights reserved. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public + * License v2 as published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + * + * You should have received a copy of the GNU General Public + * License along with this program; if not, write to the + * Free Software Foundation, Inc., 59 Temple Place - Suite 330, + * Boston, MA 021110-1307, USA. + */ + +#include <linux/fs.h> +#include <linux/sched.h> +#include <linux/writeback.h> +#include <linux/pagemap.h> +#include "ctree.h" +#include "disk-io.h" +#include "transaction.h" +#include "locking.h" +#include "ref-cache.h" +#include "tree-log.h" + +static int total_trans = 0; +extern struct kmem_cache *btrfs_trans_handle_cachep; +extern struct kmem_cache *btrfs_transaction_cachep; + +#define BTRFS_ROOT_TRANS_TAG 0 + +static noinline void put_transaction(struct btrfs_transaction *transaction) +{ + WARN_ON(transaction->use_count == 0); + transaction->use_count--; + if (transaction->use_count == 0) { + WARN_ON(total_trans == 0); + total_trans--; + list_del_init(&transaction->list); + memset(transaction, 0, sizeof(*transaction)); + kmem_cache_free(btrfs_transaction_cachep, transaction); + } +} + +/* + * either allocate a new transaction or hop into the existing one + */ +static noinline int join_transaction(struct btrfs_root *root) +{ + struct btrfs_transaction *cur_trans; + cur_trans = root->fs_info->running_transaction; + if (!cur_trans) { + cur_trans = kmem_cache_alloc(btrfs_transaction_cachep, + GFP_NOFS); + total_trans++; + BUG_ON(!cur_trans); + root->fs_info->generation++; + root->fs_info->last_alloc = 0; + root->fs_info->last_data_alloc = 0; + cur_trans->num_writers = 1; + cur_trans->num_joined = 0; + cur_trans->transid = root->fs_info->generation; + init_waitqueue_head(&cur_trans->writer_wait); + init_waitqueue_head(&cur_trans->commit_wait); + cur_trans->in_commit = 0; + cur_trans->blocked = 0; + cur_trans->use_count = 1; + cur_trans->commit_done = 0; + cur_trans->start_time = get_seconds(); + INIT_LIST_HEAD(&cur_trans->pending_snapshots); + list_add_tail(&cur_trans->list, &root->fs_info->trans_list); + extent_io_tree_init(&cur_trans->dirty_pages, + root->fs_info->btree_inode->i_mapping, + GFP_NOFS); + spin_lock(&root->fs_info->new_trans_lock); + root->fs_info->running_transaction = cur_trans; + spin_unlock(&root->fs_info->new_trans_lock); + } else { + cur_trans->num_writers++; + cur_trans->num_joined++; + } + + return 0; +} + +/* + * this does all the record keeping required to make sure that a + * reference counted root is properly recorded in a given transaction. + * This is required to make sure the old root from before we joined the transaction + * is deleted when the transaction commits + */ +noinline int btrfs_record_root_in_trans(struct btrfs_root *root) +{ + struct btrfs_dirty_root *dirty; + u64 running_trans_id = root->fs_info->running_transaction->transid; + if (root->ref_cows && root->last_trans < running_trans_id) { + WARN_ON(root == root->fs_info->extent_root); + if (root->root_item.refs != 0) { + radix_tree_tag_set(&root->fs_info->fs_roots_radix, + (unsigned long)root->root_key.objectid, + BTRFS_ROOT_TRANS_TAG); + + dirty = kmalloc(sizeof(*dirty), GFP_NOFS); + BUG_ON(!dirty); + dirty->root = kmalloc(sizeof(*dirty->root), GFP_NOFS); + BUG_ON(!dirty->root); + dirty->latest_root = root; + INIT_LIST_HEAD(&dirty->list); + + root->commit_root = btrfs_root_node(root); + + memcpy(dirty->root, root, sizeof(*root)); + spin_lock_init(&dirty->root->node_lock); + spin_lock_init(&dirty->root->list_lock); + mutex_init(&dirty->root->objectid_mutex); + mutex_init(&dirty->root->log_mutex); + INIT_LIST_HEAD(&dirty->root->dead_list); + dirty->root->node = root->commit_root; + dirty->root->commit_root = NULL; + + spin_lock(&root->list_lock); + list_add(&dirty->root->dead_list, &root->dead_list); + spin_unlock(&root->list_lock); + + root->dirty_root = dirty; + } else { + WARN_ON(1); + } + root->last_trans = running_trans_id; + } + return 0; +} + +/* wait for commit against the current transaction to become unblocked + * when this is done, it is safe to start a new transaction, but the current + * transaction might not be fully on disk. + */ +static void wait_current_trans(struct btrfs_root *root) +{ + struct btrfs_transaction *cur_trans; + + cur_trans = root->fs_info->running_transaction; + if (cur_trans && cur_trans->blocked) { + DEFINE_WAIT(wait); + cur_trans->use_count++; + while(1) { + prepare_to_wait(&root->fs_info->transaction_wait, &wait, + TASK_UNINTERRUPTIBLE); + if (cur_trans->blocked) { + mutex_unlock(&root->fs_info->trans_mutex); + schedule(); + mutex_lock(&root->fs_info->trans_mutex); + finish_wait(&root->fs_info->transaction_wait, + &wait); + } else { + finish_wait(&root->fs_info->transaction_wait, + &wait); + break; + } + } + put_transaction(cur_trans); + } +} + +static struct btrfs_trans_handle *start_transaction(struct btrfs_root *root, + int num_blocks, int wait) +{ + struct btrfs_trans_handle *h = + kmem_cache_alloc(btrfs_trans_handle_cachep, GFP_NOFS); + int ret; + + mutex_lock(&root->fs_info->trans_mutex); + if (!root->fs_info->log_root_recovering && + ((wait == 1 && !root->fs_info->open_ioctl_trans) || wait == 2)) + wait_current_trans(root); + ret = join_transaction(root); + BUG_ON(ret); + + btrfs_record_root_in_trans(root); + h->transid = root->fs_info->running_transaction->transid; + h->transaction = root->fs_info->running_transaction; + h->blocks_reserved = num_blocks; + h->blocks_used = 0; + h->block_group = NULL; + h->alloc_exclude_nr = 0; + h->alloc_exclude_start = 0; + root->fs_info->running_transaction->use_count++; + mutex_unlock(&root->fs_info->trans_mutex); + return h; +} + +struct btrfs_trans_handle *btrfs_start_transaction(struct btrfs_root *root, + int num_blocks) +{ + return start_transaction(root, num_blocks, 1); +} +struct btrfs_trans_handle *btrfs_join_transaction(struct btrfs_root *root, + int num_blocks) +{ + return start_transaction(root, num_blocks, 0); +} + +struct btrfs_trans_handle *btrfs_start_ioctl_transaction(struct btrfs_root *r, + int num_blocks) +{ + return start_transaction(r, num_blocks, 2); +} + +/* wait for a transaction commit to be fully complete */ +static noinline int wait_for_commit(struct btrfs_root *root, + struct btrfs_transaction *commit) +{ + DEFINE_WAIT(wait); + mutex_lock(&root->fs_info->trans_mutex); + while(!commit->commit_done) { + prepare_to_wait(&commit->commit_wait, &wait, + TASK_UNINTERRUPTIBLE); + if (commit->commit_done) + break; + mutex_unlock(&root->fs_info->trans_mutex); + schedule(); + mutex_lock(&root->fs_info->trans_mutex); + } + mutex_unlock(&root->fs_info->trans_mutex); + finish_wait(&commit->commit_wait, &wait); + return 0; +} + +/* + * rate limit against the drop_snapshot code. This helps to slow down new operations + * if the drop_snapshot code isn't able to keep up. + */ +static void throttle_on_drops(struct btrfs_root *root) +{ + struct btrfs_fs_info *info = root->fs_info; + int harder_count = 0; + +harder: + if (atomic_read(&info->throttles)) { + DEFINE_WAIT(wait); + int thr; + thr = atomic_read(&info->throttle_gen); + + do { + prepare_to_wait(&info->transaction_throttle, + &wait, TASK_UNINTERRUPTIBLE); + if (!atomic_read(&info->throttles)) { + finish_wait(&info->transaction_throttle, &wait); + break; + } + schedule(); + finish_wait(&info->transaction_throttle, &wait); + } while (thr == atomic_read(&info->throttle_gen)); + harder_count++; + + if (root->fs_info->total_ref_cache_size > 1 * 1024 * 1024 && + harder_count < 2) + goto harder; + + if (root->fs_info->total_ref_cache_size > 5 * 1024 * 1024 && + harder_count < 10) + goto harder; + + if (root->fs_info->total_ref_cache_size > 10 * 1024 * 1024 && + harder_count < 20) + goto harder; + } +} + +void btrfs_throttle(struct btrfs_root *root) +{ + mutex_lock(&root->fs_info->trans_mutex); + if (!root->fs_info->open_ioctl_trans) + wait_current_trans(root); + mutex_unlock(&root->fs_info->trans_mutex); + + throttle_on_drops(root); +} + +static int __btrfs_end_transaction(struct btrfs_trans_handle *trans, + struct btrfs_root *root, int throttle) +{ + struct btrfs_transaction *cur_trans; + struct btrfs_fs_info *info = root->fs_info; + + mutex_lock(&info->trans_mutex); + cur_trans = info->running_transaction; + WARN_ON(cur_trans != trans->transaction); + WARN_ON(cur_trans->num_writers < 1); + cur_trans->num_writers--; + + if (waitqueue_active(&cur_trans->writer_wait)) + wake_up(&cur_trans->writer_wait); + put_transaction(cur_trans); + mutex_unlock(&info->trans_mutex); + memset(trans, 0, sizeof(*trans)); + kmem_cache_free(btrfs_trans_handle_cachep, trans); + + if (throttle) + throttle_on_drops(root); + + return 0; +} + +int btrfs_end_transaction(struct btrfs_trans_handle *trans, + struct btrfs_root *root) +{ + return __btrfs_end_transaction(trans, root, 0); +} + +int btrfs_end_transaction_throttle(struct btrfs_trans_handle *trans, + struct btrfs_root *root) +{ + return __btrfs_end_transaction(trans, root, 1); +} + +/* + * when btree blocks are allocated, they have some corresponding bits set for + * them in one of two extent_io trees. This is used to make sure all of + * those extents are on disk for transaction or log commit + */ +int btrfs_write_and_wait_marked_extents(struct btrfs_root *root, + struct extent_io_tree *dirty_pages) +{ + int ret; + int err = 0; + int werr = 0; + struct page *page; + struct inode *btree_inode = root->fs_info->btree_inode; + u64 start = 0; + u64 end; + unsigned long index; + + while(1) { + ret = find_first_extent_bit(dirty_pages, start, &start, &end, + EXTENT_DIRTY); + if (ret) + break; + while(start <= end) { + cond_resched(); + + index = start >> PAGE_CACHE_SHIFT; + start = (u64)(index + 1) << PAGE_CACHE_SHIFT; + page = find_get_page(btree_inode->i_mapping, index); + if (!page) + continue; + + btree_lock_page_hook(page); + if (!page->mapping) { + unlock_page(page); + page_cache_release(page); + continue; + } + + if (PageWriteback(page)) { + if (PageDirty(page)) + wait_on_page_writeback(page); + else { + unlock_page(page); + page_cache_release(page); + continue; + } + } + err = write_one_page(page, 0); + if (err) + werr = err; + page_cache_release(page); + } + } + while(1) { + ret = find_first_extent_bit(dirty_pages, 0, &start, &end, + EXTENT_DIRTY); + if (ret) + break; + + clear_extent_dirty(dirty_pages, start, end, GFP_NOFS); + while(start <= end) { + index = start >> PAGE_CACHE_SHIFT; + start = (u64)(index + 1) << PAGE_CACHE_SHIFT; + page = find_get_page(btree_inode->i_mapping, index); + if (!page) + continue; + if (PageDirty(page)) { + btree_lock_page_hook(page); + wait_on_page_writeback(page); + err = write_one_page(page, 0); + if (err) + werr = err; + } + wait_on_page_writeback(page); + page_cache_release(page); + cond_resched(); + } + } + if (err) + werr = err; + return werr; +} + +int btrfs_write_and_wait_transaction(struct btrfs_trans_handle *trans, + struct btrfs_root *root) +{ + if (!trans || !trans->transaction) { + struct inode *btree_inode; + btree_inode = root->fs_info->btree_inode; + return filemap_write_and_wait(btree_inode->i_mapping); + } + return btrfs_write_and_wait_marked_extents(root, + &trans->transaction->dirty_pages); +} + +/* + * this is used to update the root pointer in the tree of tree roots. + * + * But, in the case of the extent allocation tree, updating the root + * pointer may allocate blocks which may change the root of the extent + * allocation tree. + * + * So, this loops and repeats and makes sure the cowonly root didn't + * change while the root pointer was being updated in the metadata. + */ +static int update_cowonly_root(struct btrfs_trans_handle *trans, + struct btrfs_root *root) +{ + int ret; + u64 old_root_bytenr; + struct btrfs_root *tree_root = root->fs_info->tree_root; + + btrfs_write_dirty_block_groups(trans, root); + while(1) { + old_root_bytenr = btrfs_root_bytenr(&root->root_item); + if (old_root_bytenr == root->node->start) + break; + btrfs_set_root_bytenr(&root->root_item, + root->node->start); + btrfs_set_root_level(&root->root_item, + btrfs_header_level(root->node)); + ret = btrfs_update_root(trans, tree_root, + &root->root_key, + &root->root_item); + BUG_ON(ret); + btrfs_write_dirty_block_groups(trans, root); + } + return 0; +} + +/* + * update all the cowonly tree roots on disk + */ +int btrfs_commit_tree_roots(struct btrfs_trans_handle *trans, + struct btrfs_root *root) +{ + struct btrfs_fs_info *fs_info = root->fs_info; + struct list_head *next; + + while(!list_empty(&fs_info->dirty_cowonly_roots)) { + next = fs_info->dirty_cowonly_roots.next; + list_del_init(next); + root = list_entry(next, struct btrfs_root, dirty_list); + update_cowonly_root(trans, root); + } + return 0; +} + +/* + * dead roots are old snapshots that need to be deleted. This allocates + * a dirty root struct and adds it into the list of dead roots that need to + * be deleted + */ +int btrfs_add_dead_root(struct btrfs_root *root, struct btrfs_root *latest) +{ + struct btrfs_dirty_root *dirty; + + dirty = kmalloc(sizeof(*dirty), GFP_NOFS); + if (!dirty) + return -ENOMEM; + dirty->root = root; + dirty->latest_root = latest; + + mutex_lock(&root->fs_info->trans_mutex); + list_add(&dirty->list, &latest->fs_info->dead_roots); + mutex_unlock(&root->fs_info->trans_mutex); + return 0; +} + +/* + * at transaction commit time we need to schedule the old roots for + * deletion via btrfs_drop_snapshot. This runs through all the + * reference counted roots that were modified in the current + * transaction and puts them into the drop list + */ +static noinline int add_dirty_roots(struct btrfs_trans_handle *trans, + struct radix_tree_root *radix, + struct list_head *list) +{ + struct btrfs_dirty_root *dirty; + struct btrfs_root *gang[8]; + struct btrfs_root *root; + int i; + int ret; + int err = 0; + u32 refs; + + while(1) { + ret = radix_tree_gang_lookup_tag(radix, (void **)gang, 0, + ARRAY_SIZE(gang), + BTRFS_ROOT_TRANS_TAG); + if (ret == 0) + break; + for (i = 0; i < ret; i++) { + root = gang[i]; + radix_tree_tag_clear(radix, + (unsigned long)root->root_key.objectid, + BTRFS_ROOT_TRANS_TAG); + + BUG_ON(!root->ref_tree); + dirty = root->dirty_root; + + btrfs_free_log(trans, root); + btrfs_free_reloc_root(root); + + if (root->commit_root == root->node) { + WARN_ON(root->node->start != + btrfs_root_bytenr(&root->root_item)); + + free_extent_buffer(root->commit_root); + root->commit_root = NULL; + root->dirty_root = NULL; + + spin_lock(&root->list_lock); + list_del_init(&dirty->root->dead_list); + spin_unlock(&root->list_lock); + + kfree(dirty->root); + kfree(dirty); + + /* make sure to update the root on disk + * so we get any updates to the block used + * counts + */ + err = btrfs_update_root(trans, + root->fs_info->tree_root, + &root->root_key, + &root->root_item); + continue; + } + + memset(&root->root_item.drop_progress, 0, + sizeof(struct btrfs_disk_key)); + root->root_item.drop_level = 0; + root->commit_root = NULL; + root->dirty_root = NULL; + root->root_key.offset = root->fs_info->generation; + btrfs_set_root_bytenr(&root->root_item, + root->node->start); + btrfs_set_root_level(&root->root_item, + btrfs_header_level(root->node)); + err = btrfs_insert_root(trans, root->fs_info->tree_root, + &root->root_key, + &root->root_item); + if (err) + break; + + refs = btrfs_root_refs(&dirty->root->root_item); + btrfs_set_root_refs(&dirty->root->root_item, refs - 1); + err = btrfs_update_root(trans, root->fs_info->tree_root, + &dirty->root->root_key, + &dirty->root->root_item); + + BUG_ON(err); + if (refs == 1) { + list_add(&dirty->list, list); + } else { + WARN_ON(1); + free_extent_buffer(dirty->root->node); + kfree(dirty->root); + kfree(dirty); + } + } + } + return err; +} + +/* + * defrag a given btree. If cacheonly == 1, this won't read from the disk, + * otherwise every leaf in the btree is read and defragged. + */ +int btrfs_defrag_root(struct btrfs_root *root, int cacheonly) +{ + struct btrfs_fs_info *info = root->fs_info; + int ret; + struct btrfs_trans_handle *trans; + unsigned long nr; + + smp_mb(); + if (root->defrag_running) + return 0; + trans = btrfs_start_transaction(root, 1); + while (1) { + root->defrag_running = 1; + ret = btrfs_defrag_leaves(trans, root, cacheonly); + nr = trans->blocks_used; + btrfs_end_transaction(trans, root); + btrfs_btree_balance_dirty(info->tree_root, nr); + cond_resched(); + + trans = btrfs_start_transaction(root, 1); + if (root->fs_info->closing || ret != -EAGAIN) + break; + } + root->defrag_running = 0; + smp_mb(); + btrfs_end_transaction(trans, root); + return 0; +} + +/* + * Given a list of roots that need to be deleted, call btrfs_drop_snapshot on + * all of them + */ +static noinline int drop_dirty_roots(struct btrfs_root *tree_root, + struct list_head *list) +{ + struct btrfs_dirty_root *dirty; + struct btrfs_trans_handle *trans; + unsigned long nr; + u64 num_bytes; + u64 bytes_used; + u64 max_useless; + int ret = 0; + int err; + + while(!list_empty(list)) { + struct btrfs_root *root; + + dirty = list_entry(list->prev, struct btrfs_dirty_root, list); + list_del_init(&dirty->list); + + num_bytes = btrfs_root_used(&dirty->root->root_item); + root = dirty->latest_root; + atomic_inc(&root->fs_info->throttles); + + while(1) { + trans = btrfs_start_transaction(tree_root, 1); + mutex_lock(&root->fs_info->drop_mutex); + ret = btrfs_drop_snapshot(trans, dirty->root); + if (ret != -EAGAIN) { + break; + } + mutex_unlock(&root->fs_info->drop_mutex); + + err = btrfs_update_root(trans, + tree_root, + &dirty->root->root_key, + &dirty->root->root_item); + if (err) + ret = err; + nr = trans->blocks_used; + ret = btrfs_end_transaction(trans, tree_root); + BUG_ON(ret); + + btrfs_btree_balance_dirty(tree_root, nr); + cond_resched(); + } + BUG_ON(ret); + atomic_dec(&root->fs_info->throttles); + wake_up(&root->fs_info->transaction_throttle); + + mutex_lock(&root->fs_info->alloc_mutex); + num_bytes -= btrfs_root_used(&dirty->root->root_item); + bytes_used = btrfs_root_used(&root->root_item); + if (num_bytes) { + btrfs_record_root_in_trans(root); + btrfs_set_root_used(&root->root_item, + bytes_used - num_bytes); + } + mutex_unlock(&root->fs_info->alloc_mutex); + + ret = btrfs_del_root(trans, tree_root, &dirty->root->root_key); + if (ret) { + BUG(); + break; + } + mutex_unlock(&root->fs_info->drop_mutex); + + spin_lock(&root->list_lock); + list_del_init(&dirty->root->dead_list); + if (!list_empty(&root->dead_list)) { + struct btrfs_root *oldest; + oldest = list_entry(root->dead_list.prev, + struct btrfs_root, dead_list); + max_useless = oldest->root_key.offset - 1; + } else { + max_useless = root->root_key.offset - 1; + } + spin_unlock(&root->list_lock); + + nr = trans->blocks_used; + ret = btrfs_end_transaction(trans, tree_root); + BUG_ON(ret); + + ret = btrfs_remove_leaf_refs(root, max_useless, 0); + BUG_ON(ret); + + free_extent_buffer(dirty->root->node); + kfree(dirty->root); + kfree(dirty); + + btrfs_btree_balance_dirty(tree_root, nr); + cond_resched(); + } + return ret; +} + +/* + * new snapshots need to be created at a very specific time in the + * transaction commit. This does the actual creation + */ +static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans, + struct btrfs_fs_info *fs_info, + struct btrfs_pending_snapshot *pending) +{ + struct btrfs_key key; + struct btrfs_root_item *new_root_item; + struct btrfs_root *tree_root = fs_info->tree_root; + struct btrfs_root *root = pending->root; + struct extent_buffer *tmp; + struct extent_buffer *old; + int ret; + int namelen; + u64 objectid; + + new_root_item = kmalloc(sizeof(*new_root_item), GFP_NOFS); + if (!new_root_item) { + ret = -ENOMEM; + goto fail; + } + ret = btrfs_find_free_objectid(trans, tree_root, 0, &objectid); + if (ret) + goto fail; + + memcpy(new_root_item, &root->root_item, sizeof(*new_root_item)); + + key.objectid = objectid; + key.offset = trans->transid; + btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY); + + old = btrfs_lock_root_node(root); + btrfs_cow_block(trans, root, old, NULL, 0, &old, 0); + + btrfs_copy_root(trans, root, old, &tmp, objectid); + btrfs_tree_unlock(old); + free_extent_buffer(old); + + btrfs_set_root_bytenr(new_root_item, tmp->start); + btrfs_set_root_level(new_root_item, btrfs_header_level(tmp)); + ret = btrfs_insert_root(trans, root->fs_info->tree_root, &key, + new_root_item); + btrfs_tree_unlock(tmp); + free_extent_buffer(tmp); + if (ret) + goto fail; + + /* + * insert the directory item + */ + key.offset = (u64)-1; + namelen = strlen(pending->name); + ret = btrfs_insert_dir_item(trans, root->fs_info->tree_root, + pending->name, namelen, + root->fs_info->sb->s_root->d_inode->i_ino, + &key, BTRFS_FT_DIR, 0); + + if (ret) + goto fail; + + ret = btrfs_insert_inode_ref(trans, root->fs_info->tree_root, + pending->name, strlen(pending->name), objectid, + root->fs_info->sb->s_root->d_inode->i_ino, 0); + + /* Invalidate existing dcache entry for new snapshot. */ + btrfs_invalidate_dcache_root(root, pending->name, namelen); + +fail: + kfree(new_root_item); + return ret; +} + +/* + * create all the snapshots we've scheduled for creation + */ +static noinline int create_pending_snapshots(struct btrfs_trans_handle *trans, + struct btrfs_fs_info *fs_info) +{ + struct btrfs_pending_snapshot *pending; + struct list_head *head = &trans->transaction->pending_snapshots; + int ret; + + while(!list_empty(head)) { + pending = list_entry(head->next, + struct btrfs_pending_snapshot, list); + ret = create_pending_snapshot(trans, fs_info, pending); + BUG_ON(ret); + list_del(&pending->list); + kfree(pending->name); + kfree(pending); + } + return 0; +} + +int btrfs_commit_transaction(struct btrfs_trans_handle *trans, + struct btrfs_root *root) +{ + unsigned long joined = 0; + unsigned long timeout = 1; + struct btrfs_transaction *cur_trans; + struct btrfs_transaction *prev_trans = NULL; + struct btrfs_root *chunk_root = root->fs_info->chunk_root; + struct list_head dirty_fs_roots; + struct extent_io_tree *pinned_copy; + DEFINE_WAIT(wait); + int ret; + + INIT_LIST_HEAD(&dirty_fs_roots); + mutex_lock(&root->fs_info->trans_mutex); + if (trans->transaction->in_commit) { + cur_trans = trans->transaction; + trans->transaction->use_count++; + mutex_unlock(&root->fs_info->trans_mutex); + btrfs_end_transaction(trans, root); + + ret = wait_for_commit(root, cur_trans); + BUG_ON(ret); + + mutex_lock(&root->fs_info->trans_mutex); + put_transaction(cur_trans); + mutex_unlock(&root->fs_info->trans_mutex); + + return 0; + } + + pinned_copy = kmalloc(sizeof(*pinned_copy), GFP_NOFS); + if (!pinned_copy) + return -ENOMEM; + + extent_io_tree_init(pinned_copy, + root->fs_info->btree_inode->i_mapping, GFP_NOFS); + + trans->transaction->in_commit = 1; + trans->transaction->blocked = 1; + cur_trans = trans->transaction; + if (cur_trans->list.prev != &root->fs_info->trans_list) { + prev_trans = list_entry(cur_trans->list.prev, + struct btrfs_transaction, list); + if (!prev_trans->commit_done) { + prev_trans->use_count++; + mutex_unlock(&root->fs_info->trans_mutex); + + wait_for_commit(root, prev_trans); + + mutex_lock(&root->fs_info->trans_mutex); + put_transaction(prev_trans); + } + } + + do { + int snap_pending = 0; + joined = cur_trans->num_joined; + if (!list_empty(&trans->transaction->pending_snapshots)) + snap_pending = 1; + + WARN_ON(cur_trans != trans->transaction); + prepare_to_wait(&cur_trans->writer_wait, &wait, + TASK_UNINTERRUPTIBLE); + + if (cur_trans->num_writers > 1) + timeout = MAX_SCHEDULE_TIMEOUT; + else + timeout = 1; + + mutex_unlock(&root->fs_info->trans_mutex); + + if (snap_pending) { + ret = btrfs_wait_ordered_extents(root, 1); + BUG_ON(ret); + } + + schedule_timeout(timeout); + + mutex_lock(&root->fs_info->trans_mutex); + finish_wait(&cur_trans->writer_wait, &wait); + } while (cur_trans->num_writers > 1 || + (cur_trans->num_joined != joined)); + + ret = create_pending_snapshots(trans, root->fs_info); + BUG_ON(ret); + + WARN_ON(cur_trans != trans->transaction); + + /* btrfs_commit_tree_roots is responsible for getting the + * various roots consistent with each other. Every pointer + * in the tree of tree roots has to point to the most up to date + * root for every subvolume and other tree. So, we have to keep + * the tree logging code from jumping in and changing any + * of the trees. + * + * At this point in the commit, there can't be any tree-log + * writers, but a little lower down we drop the trans mutex + * and let new people in. By holding the tree_log_mutex + * from now until after the super is written, we avoid races + * with the tree-log code. + */ + mutex_lock(&root->fs_info->tree_log_mutex); + /* + * keep tree reloc code from adding new reloc trees + */ + mutex_lock(&root->fs_info->tree_reloc_mutex); + + + ret = add_dirty_roots(trans, &root->fs_info->fs_roots_radix, + &dirty_fs_roots); + BUG_ON(ret); + + /* add_dirty_roots gets rid of all the tree log roots, it is now + * safe to free the root of tree log roots + */ + btrfs_free_log_root_tree(trans, root->fs_info); + + btrfs_free_reloc_mappings(root); + + ret = btrfs_commit_tree_roots(trans, root); + BUG_ON(ret); + + cur_trans = root->fs_info->running_transaction; + spin_lock(&root->fs_info->new_trans_lock); + root->fs_info->running_transaction = NULL; + spin_unlock(&root->fs_info->new_trans_lock); + btrfs_set_super_generation(&root->fs_info->super_copy, + cur_trans->transid); + btrfs_set_super_root(&root->fs_info->super_copy, + root->fs_info->tree_root->node->start); + btrfs_set_super_root_level(&root->fs_info->super_copy, + btrfs_header_level(root->fs_info->tree_root->node)); + + btrfs_set_super_chunk_root(&root->fs_info->super_copy, + chunk_root->node->start); + btrfs_set_super_chunk_root_level(&root->fs_info->super_copy, + btrfs_header_level(chunk_root->node)); + + if (!root->fs_info->log_root_recovering) { + btrfs_set_super_log_root(&root->fs_info->super_copy, 0); + btrfs_set_super_log_root_level(&root->fs_info->super_copy, 0); + } + + memcpy(&root->fs_info->super_for_commit, &root->fs_info->super_copy, + sizeof(root->fs_info->super_copy)); + + btrfs_copy_pinned(root, pinned_copy); + + trans->transaction->blocked = 0; + wake_up(&root->fs_info->transaction_throttle); + wake_up(&root->fs_info->transaction_wait); + + mutex_unlock(&root->fs_info->trans_mutex); + ret = btrfs_write_and_wait_transaction(trans, root); + BUG_ON(ret); + write_ctree_super(trans, root); + + /* + * the super is written, we can safely allow the tree-loggers + * to go about their business + */ + mutex_unlock(&root->fs_info->tree_log_mutex); + + btrfs_finish_extent_commit(trans, root, pinned_copy); + kfree(pinned_copy); + + btrfs_drop_dead_reloc_roots(root); + mutex_unlock(&root->fs_info->tree_reloc_mutex); + + mutex_lock(&root->fs_info->trans_mutex); + + cur_trans->commit_done = 1; + root->fs_info->last_trans_committed = cur_trans->transid; + wake_up(&cur_trans->commit_wait); + put_transaction(cur_trans); + put_transaction(cur_trans); + + list_splice_init(&dirty_fs_roots, &root->fs_info->dead_roots); + if (root->fs_info->closing) + list_splice_init(&root->fs_info->dead_roots, &dirty_fs_roots); + + mutex_unlock(&root->fs_info->trans_mutex); + kmem_cache_free(btrfs_trans_handle_cachep, trans); + + if (root->fs_info->closing) { + drop_dirty_roots(root->fs_info->tree_root, &dirty_fs_roots); + } + return ret; +} + +/* + * interface function to delete all the snapshots we have scheduled for deletion + */ +int btrfs_clean_old_snapshots(struct btrfs_root *root) +{ + struct list_head dirty_roots; + INIT_LIST_HEAD(&dirty_roots); +again: + mutex_lock(&root->fs_info->trans_mutex); + list_splice_init(&root->fs_info->dead_roots, &dirty_roots); + mutex_unlock(&root->fs_info->trans_mutex); + + if (!list_empty(&dirty_roots)) { + drop_dirty_roots(root, &dirty_roots); + goto again; + } + return 0; +} |