| /* |
| * 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/slab.h> |
| #include <linux/sched.h> |
| #include <linux/writeback.h> |
| #include <linux/pagemap.h> |
| #include <linux/blkdev.h> |
| #include "ctree.h" |
| #include "disk-io.h" |
| #include "transaction.h" |
| #include "locking.h" |
| #include "tree-log.h" |
| |
| #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) { |
| list_del_init(&transaction->list); |
| memset(transaction, 0, sizeof(*transaction)); |
| kmem_cache_free(btrfs_transaction_cachep, transaction); |
| } |
| } |
| |
| static noinline void switch_commit_root(struct btrfs_root *root) |
| { |
| free_extent_buffer(root->commit_root); |
| root->commit_root = btrfs_root_node(root); |
| } |
| |
| /* |
| * 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); |
| BUG_ON(!cur_trans); |
| root->fs_info->generation++; |
| 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(); |
| |
| cur_trans->delayed_refs.root = RB_ROOT; |
| cur_trans->delayed_refs.num_entries = 0; |
| cur_trans->delayed_refs.num_heads_ready = 0; |
| cur_trans->delayed_refs.num_heads = 0; |
| cur_trans->delayed_refs.flushing = 0; |
| cur_trans->delayed_refs.run_delayed_start = 0; |
| spin_lock_init(&cur_trans->delayed_refs.lock); |
| |
| 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 |
| */ |
| static noinline int record_root_in_trans(struct btrfs_trans_handle *trans, |
| struct btrfs_root *root) |
| { |
| if (root->ref_cows && root->last_trans < trans->transid) { |
| WARN_ON(root == root->fs_info->extent_root); |
| WARN_ON(root->commit_root != root->node); |
| |
| radix_tree_tag_set(&root->fs_info->fs_roots_radix, |
| (unsigned long)root->root_key.objectid, |
| BTRFS_ROOT_TRANS_TAG); |
| root->last_trans = trans->transid; |
| btrfs_init_reloc_root(trans, root); |
| } |
| return 0; |
| } |
| |
| int btrfs_record_root_in_trans(struct btrfs_trans_handle *trans, |
| struct btrfs_root *root) |
| { |
| if (!root->ref_cows) |
| return 0; |
| |
| mutex_lock(&root->fs_info->trans_mutex); |
| if (root->last_trans == trans->transid) { |
| mutex_unlock(&root->fs_info->trans_mutex); |
| return 0; |
| } |
| |
| record_root_in_trans(trans, root); |
| mutex_unlock(&root->fs_info->trans_mutex); |
| 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) |
| break; |
| mutex_unlock(&root->fs_info->trans_mutex); |
| schedule(); |
| mutex_lock(&root->fs_info->trans_mutex); |
| } |
| finish_wait(&root->fs_info->transaction_wait, &wait); |
| put_transaction(cur_trans); |
| } |
| } |
| |
| enum btrfs_trans_type { |
| TRANS_START, |
| TRANS_JOIN, |
| TRANS_USERSPACE, |
| }; |
| |
| static int may_wait_transaction(struct btrfs_root *root, int type) |
| { |
| if (!root->fs_info->log_root_recovering && |
| ((type == TRANS_START && !root->fs_info->open_ioctl_trans) || |
| type == TRANS_USERSPACE)) |
| return 1; |
| return 0; |
| } |
| |
| static struct btrfs_trans_handle *start_transaction(struct btrfs_root *root, |
| u64 num_items, int type) |
| { |
| struct btrfs_trans_handle *h; |
| struct btrfs_transaction *cur_trans; |
| int retries = 0; |
| int ret; |
| again: |
| h = kmem_cache_alloc(btrfs_trans_handle_cachep, GFP_NOFS); |
| if (!h) |
| return ERR_PTR(-ENOMEM); |
| |
| mutex_lock(&root->fs_info->trans_mutex); |
| if (may_wait_transaction(root, type)) |
| wait_current_trans(root); |
| |
| ret = join_transaction(root); |
| BUG_ON(ret); |
| |
| cur_trans = root->fs_info->running_transaction; |
| cur_trans->use_count++; |
| mutex_unlock(&root->fs_info->trans_mutex); |
| |
| h->transid = cur_trans->transid; |
| h->transaction = cur_trans; |
| h->blocks_used = 0; |
| h->block_group = 0; |
| h->bytes_reserved = 0; |
| h->delayed_ref_updates = 0; |
| h->block_rsv = NULL; |
| |
| smp_mb(); |
| if (cur_trans->blocked && may_wait_transaction(root, type)) { |
| btrfs_commit_transaction(h, root); |
| goto again; |
| } |
| |
| if (num_items > 0) { |
| ret = btrfs_trans_reserve_metadata(h, root, num_items, |
| &retries); |
| if (ret == -EAGAIN) { |
| btrfs_commit_transaction(h, root); |
| goto again; |
| } |
| if (ret < 0) { |
| btrfs_end_transaction(h, root); |
| return ERR_PTR(ret); |
| } |
| } |
| |
| mutex_lock(&root->fs_info->trans_mutex); |
| record_root_in_trans(h, root); |
| mutex_unlock(&root->fs_info->trans_mutex); |
| |
| if (!current->journal_info && type != TRANS_USERSPACE) |
| current->journal_info = h; |
| return h; |
| } |
| |
| struct btrfs_trans_handle *btrfs_start_transaction(struct btrfs_root *root, |
| int num_items) |
| { |
| return start_transaction(root, num_items, TRANS_START); |
| } |
| struct btrfs_trans_handle *btrfs_join_transaction(struct btrfs_root *root, |
| int num_blocks) |
| { |
| return start_transaction(root, 0, TRANS_JOIN); |
| } |
| |
| struct btrfs_trans_handle *btrfs_start_ioctl_transaction(struct btrfs_root *r, |
| int num_blocks) |
| { |
| return start_transaction(r, 0, TRANS_USERSPACE); |
| } |
| |
| /* 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; |
| } |
| |
| #if 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; |
| } |
| } |
| #endif |
| |
| 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); |
| } |
| |
| static int should_end_transaction(struct btrfs_trans_handle *trans, |
| struct btrfs_root *root) |
| { |
| int ret; |
| ret = btrfs_block_rsv_check(trans, root, |
| &root->fs_info->global_block_rsv, 0, 5); |
| return ret ? 1 : 0; |
| } |
| |
| int btrfs_should_end_transaction(struct btrfs_trans_handle *trans, |
| struct btrfs_root *root) |
| { |
| struct btrfs_transaction *cur_trans = trans->transaction; |
| int updates; |
| |
| if (cur_trans->blocked || cur_trans->delayed_refs.flushing) |
| return 1; |
| |
| updates = trans->delayed_ref_updates; |
| trans->delayed_ref_updates = 0; |
| if (updates) |
| btrfs_run_delayed_refs(trans, root, updates); |
| |
| return should_end_transaction(trans, root); |
| } |
| |
| static int __btrfs_end_transaction(struct btrfs_trans_handle *trans, |
| struct btrfs_root *root, int throttle) |
| { |
| struct btrfs_transaction *cur_trans = trans->transaction; |
| struct btrfs_fs_info *info = root->fs_info; |
| int count = 0; |
| |
| while (count < 4) { |
| unsigned long cur = trans->delayed_ref_updates; |
| trans->delayed_ref_updates = 0; |
| if (cur && |
| trans->transaction->delayed_refs.num_heads_ready > 64) { |
| trans->delayed_ref_updates = 0; |
| |
| /* |
| * do a full flush if the transaction is trying |
| * to close |
| */ |
| if (trans->transaction->delayed_refs.flushing) |
| cur = 0; |
| btrfs_run_delayed_refs(trans, root, cur); |
| } else { |
| break; |
| } |
| count++; |
| } |
| |
| btrfs_trans_release_metadata(trans, root); |
| |
| if (!root->fs_info->open_ioctl_trans && |
| should_end_transaction(trans, root)) |
| trans->transaction->blocked = 1; |
| |
| if (cur_trans->blocked && !cur_trans->in_commit) { |
| if (throttle) |
| return btrfs_commit_transaction(trans, root); |
| else |
| wake_up_process(info->transaction_kthread); |
| } |
| |
| mutex_lock(&info->trans_mutex); |
| WARN_ON(cur_trans != info->running_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); |
| |
| if (current->journal_info == trans) |
| current->journal_info = NULL; |
| memset(trans, 0, sizeof(*trans)); |
| kmem_cache_free(btrfs_trans_handle_cachep, trans); |
| |
| if (throttle) |
| btrfs_run_delayed_iputs(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 sent to disk but does not wait on them |
| */ |
| int btrfs_write_marked_extents(struct btrfs_root *root, |
| struct extent_io_tree *dirty_pages, int mark) |
| { |
| 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, |
| mark); |
| 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); |
| } |
| } |
| if (err) |
| werr = err; |
| return werr; |
| } |
| |
| /* |
| * 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. We wait |
| * on all the pages and clear them from the dirty pages state tree |
| */ |
| int btrfs_wait_marked_extents(struct btrfs_root *root, |
| struct extent_io_tree *dirty_pages, int mark) |
| { |
| 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, |
| mark); |
| if (ret) |
| break; |
| |
| clear_extent_bits(dirty_pages, start, end, mark, 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; |
| } |
| |
| /* |
| * 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 mark) |
| { |
| int ret; |
| int ret2; |
| |
| ret = btrfs_write_marked_extents(root, dirty_pages, mark); |
| ret2 = btrfs_wait_marked_extents(root, dirty_pages, mark); |
| return ret || ret2; |
| } |
| |
| 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, |
| EXTENT_DIRTY); |
| } |
| |
| /* |
| * 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; |
| u64 old_root_used; |
| struct btrfs_root *tree_root = root->fs_info->tree_root; |
| |
| old_root_used = btrfs_root_used(&root->root_item); |
| 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 && |
| old_root_used == btrfs_root_used(&root->root_item)) |
| break; |
| |
| btrfs_set_root_node(&root->root_item, root->node); |
| ret = btrfs_update_root(trans, tree_root, |
| &root->root_key, |
| &root->root_item); |
| BUG_ON(ret); |
| |
| old_root_used = btrfs_root_used(&root->root_item); |
| ret = btrfs_write_dirty_block_groups(trans, root); |
| BUG_ON(ret); |
| } |
| |
| if (root != root->fs_info->extent_root) |
| switch_commit_root(root); |
| |
| return 0; |
| } |
| |
| /* |
| * update all the cowonly tree roots on disk |
| */ |
| static noinline int commit_cowonly_roots(struct btrfs_trans_handle *trans, |
| struct btrfs_root *root) |
| { |
| struct btrfs_fs_info *fs_info = root->fs_info; |
| struct list_head *next; |
| struct extent_buffer *eb; |
| int ret; |
| |
| ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1); |
| BUG_ON(ret); |
| |
| eb = btrfs_lock_root_node(fs_info->tree_root); |
| btrfs_cow_block(trans, fs_info->tree_root, eb, NULL, 0, &eb); |
| btrfs_tree_unlock(eb); |
| free_extent_buffer(eb); |
| |
| ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1); |
| BUG_ON(ret); |
| |
| 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); |
| } |
| |
| down_write(&fs_info->extent_commit_sem); |
| switch_commit_root(fs_info->extent_root); |
| up_write(&fs_info->extent_commit_sem); |
| |
| 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) |
| { |
| mutex_lock(&root->fs_info->trans_mutex); |
| list_add(&root->root_list, &root->fs_info->dead_roots); |
| mutex_unlock(&root->fs_info->trans_mutex); |
| return 0; |
| } |
| |
| /* |
| * update all the cowonly tree roots on disk |
| */ |
| static noinline int commit_fs_roots(struct btrfs_trans_handle *trans, |
| struct btrfs_root *root) |
| { |
| struct btrfs_root *gang[8]; |
| struct btrfs_fs_info *fs_info = root->fs_info; |
| int i; |
| int ret; |
| int err = 0; |
| |
| while (1) { |
| ret = radix_tree_gang_lookup_tag(&fs_info->fs_roots_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(&fs_info->fs_roots_radix, |
| (unsigned long)root->root_key.objectid, |
| BTRFS_ROOT_TRANS_TAG); |
| |
| btrfs_free_log(trans, root); |
| btrfs_update_reloc_root(trans, root); |
| btrfs_orphan_commit_root(trans, root); |
| |
| if (root->commit_root != root->node) { |
| switch_commit_root(root); |
| btrfs_set_root_node(&root->root_item, |
| root->node); |
| } |
| |
| err = btrfs_update_root(trans, fs_info->tree_root, |
| &root->root_key, |
| &root->root_item); |
| if (err) |
| break; |
| } |
| } |
| 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; |
| struct btrfs_trans_handle *trans; |
| int ret; |
| unsigned long nr; |
| |
| if (xchg(&root->defrag_running, 1)) |
| return 0; |
| |
| while (1) { |
| trans = btrfs_start_transaction(root, 0); |
| if (IS_ERR(trans)) |
| return PTR_ERR(trans); |
| |
| 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(); |
| |
| if (root->fs_info->closing || ret != -EAGAIN) |
| break; |
| } |
| root->defrag_running = 0; |
| return ret; |
| } |
| |
| #if 0 |
| /* |
| * when dropping snapshots, we generate a ton of delayed refs, and it makes |
| * sense not to join the transaction while it is trying to flush the current |
| * queue of delayed refs out. |
| * |
| * This is used by the drop snapshot code only |
| */ |
| static noinline int wait_transaction_pre_flush(struct btrfs_fs_info *info) |
| { |
| DEFINE_WAIT(wait); |
| |
| mutex_lock(&info->trans_mutex); |
| while (info->running_transaction && |
| info->running_transaction->delayed_refs.flushing) { |
| prepare_to_wait(&info->transaction_wait, &wait, |
| TASK_UNINTERRUPTIBLE); |
| mutex_unlock(&info->trans_mutex); |
| |
| schedule(); |
| |
| mutex_lock(&info->trans_mutex); |
| finish_wait(&info->transaction_wait, &wait); |
| } |
| mutex_unlock(&info->trans_mutex); |
| return 0; |
| } |
| |
| /* |
| * Given a list of roots that need to be deleted, call btrfs_drop_snapshot on |
| * all of them |
| */ |
| int btrfs_drop_dead_root(struct btrfs_root *root) |
| { |
| struct btrfs_trans_handle *trans; |
| struct btrfs_root *tree_root = root->fs_info->tree_root; |
| unsigned long nr; |
| int ret; |
| |
| while (1) { |
| /* |
| * we don't want to jump in and create a bunch of |
| * delayed refs if the transaction is starting to close |
| */ |
| wait_transaction_pre_flush(tree_root->fs_info); |
| trans = btrfs_start_transaction(tree_root, 1); |
| |
| /* |
| * we've joined a transaction, make sure it isn't |
| * closing right now |
| */ |
| if (trans->transaction->delayed_refs.flushing) { |
| btrfs_end_transaction(trans, tree_root); |
| continue; |
| } |
| |
| ret = btrfs_drop_snapshot(trans, root); |
| if (ret != -EAGAIN) |
| break; |
| |
| ret = btrfs_update_root(trans, tree_root, |
| &root->root_key, |
| &root->root_item); |
| if (ret) |
| break; |
| |
| 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); |
| |
| ret = btrfs_del_root(trans, tree_root, &root->root_key); |
| BUG_ON(ret); |
| |
| nr = trans->blocks_used; |
| ret = btrfs_end_transaction(trans, tree_root); |
| BUG_ON(ret); |
| |
| free_extent_buffer(root->node); |
| free_extent_buffer(root->commit_root); |
| kfree(root); |
| |
| btrfs_btree_balance_dirty(tree_root, nr); |
| return ret; |
| } |
| #endif |
| |
| /* |
| * 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 btrfs_root *parent_root; |
| struct inode *parent_inode; |
| struct dentry *dentry; |
| struct extent_buffer *tmp; |
| struct extent_buffer *old; |
| int ret; |
| int retries = 0; |
| u64 to_reserve = 0; |
| u64 index = 0; |
| u64 objectid; |
| |
| new_root_item = kmalloc(sizeof(*new_root_item), GFP_NOFS); |
| if (!new_root_item) { |
| pending->error = -ENOMEM; |
| goto fail; |
| } |
| |
| ret = btrfs_find_free_objectid(trans, tree_root, 0, &objectid); |
| if (ret) { |
| pending->error = ret; |
| goto fail; |
| } |
| |
| btrfs_orphan_pre_snapshot(trans, pending, &to_reserve); |
| |
| if (to_reserve > 0) { |
| ret = btrfs_block_rsv_add(trans, root, &pending->block_rsv, |
| to_reserve, &retries); |
| if (ret) { |
| pending->error = ret; |
| goto fail; |
| } |
| } |
| |
| key.objectid = objectid; |
| key.offset = (u64)-1; |
| key.type = BTRFS_ROOT_ITEM_KEY; |
| |
| trans->block_rsv = &pending->block_rsv; |
| |
| dentry = pending->dentry; |
| parent_inode = dentry->d_parent->d_inode; |
| parent_root = BTRFS_I(parent_inode)->root; |
| record_root_in_trans(trans, parent_root); |
| |
| /* |
| * insert the directory item |
| */ |
| ret = btrfs_set_inode_index(parent_inode, &index); |
| BUG_ON(ret); |
| ret = btrfs_insert_dir_item(trans, parent_root, |
| dentry->d_name.name, dentry->d_name.len, |
| parent_inode->i_ino, &key, |
| BTRFS_FT_DIR, index); |
| BUG_ON(ret); |
| |
| btrfs_i_size_write(parent_inode, parent_inode->i_size + |
| dentry->d_name.len * 2); |
| ret = btrfs_update_inode(trans, parent_root, parent_inode); |
| BUG_ON(ret); |
| |
| record_root_in_trans(trans, root); |
| btrfs_set_root_last_snapshot(&root->root_item, trans->transid); |
| memcpy(new_root_item, &root->root_item, sizeof(*new_root_item)); |
| |
| old = btrfs_lock_root_node(root); |
| btrfs_cow_block(trans, root, old, NULL, 0, &old); |
| btrfs_set_lock_blocking(old); |
| |
| btrfs_copy_root(trans, root, old, &tmp, objectid); |
| btrfs_tree_unlock(old); |
| free_extent_buffer(old); |
| |
| btrfs_set_root_node(new_root_item, tmp); |
| /* record when the snapshot was created in key.offset */ |
| key.offset = trans->transid; |
| ret = btrfs_insert_root(trans, tree_root, &key, new_root_item); |
| btrfs_tree_unlock(tmp); |
| free_extent_buffer(tmp); |
| BUG_ON(ret); |
| |
| /* |
| * insert root back/forward references |
| */ |
| ret = btrfs_add_root_ref(trans, tree_root, objectid, |
| parent_root->root_key.objectid, |
| parent_inode->i_ino, index, |
| dentry->d_name.name, dentry->d_name.len); |
| BUG_ON(ret); |
| |
| key.offset = (u64)-1; |
| pending->snap = btrfs_read_fs_root_no_name(root->fs_info, &key); |
| BUG_ON(IS_ERR(pending->snap)); |
| |
| btrfs_orphan_post_snapshot(trans, pending); |
| fail: |
| kfree(new_root_item); |
| btrfs_block_rsv_release(root, &pending->block_rsv, (u64)-1); |
| return 0; |
| } |
| |
| /* |
| * 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; |
| |
| list_for_each_entry(pending, head, list) { |
| ret = create_pending_snapshot(trans, fs_info, pending); |
| BUG_ON(ret); |
| } |
| return 0; |
| } |
| |
| static void update_super_roots(struct btrfs_root *root) |
| { |
| struct btrfs_root_item *root_item; |
| struct btrfs_super_block *super; |
| |
| super = &root->fs_info->super_copy; |
| |
| root_item = &root->fs_info->chunk_root->root_item; |
| super->chunk_root = root_item->bytenr; |
| super->chunk_root_generation = root_item->generation; |
| super->chunk_root_level = root_item->level; |
| |
| root_item = &root->fs_info->tree_root->root_item; |
| super->root = root_item->bytenr; |
| super->generation = root_item->generation; |
| super->root_level = root_item->level; |
| } |
| |
| int btrfs_transaction_in_commit(struct btrfs_fs_info *info) |
| { |
| int ret = 0; |
| spin_lock(&info->new_trans_lock); |
| if (info->running_transaction) |
| ret = info->running_transaction->in_commit; |
| spin_unlock(&info->new_trans_lock); |
| return ret; |
| } |
| |
| int btrfs_transaction_blocked(struct btrfs_fs_info *info) |
| { |
| int ret = 0; |
| spin_lock(&info->new_trans_lock); |
| if (info->running_transaction) |
| ret = info->running_transaction->blocked; |
| spin_unlock(&info->new_trans_lock); |
| return ret; |
| } |
| |
| 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; |
| DEFINE_WAIT(wait); |
| int ret; |
| int should_grow = 0; |
| unsigned long now = get_seconds(); |
| int flush_on_commit = btrfs_test_opt(root, FLUSHONCOMMIT); |
| |
| btrfs_run_ordered_operations(root, 0); |
| |
| /* make a pass through all the delayed refs we have so far |
| * any runnings procs may add more while we are here |
| */ |
| ret = btrfs_run_delayed_refs(trans, root, 0); |
| BUG_ON(ret); |
| |
| btrfs_trans_release_metadata(trans, root); |
| |
| cur_trans = trans->transaction; |
| /* |
| * set the flushing flag so procs in this transaction have to |
| * start sending their work down. |
| */ |
| cur_trans->delayed_refs.flushing = 1; |
| |
| ret = btrfs_run_delayed_refs(trans, root, 0); |
| BUG_ON(ret); |
| |
| mutex_lock(&root->fs_info->trans_mutex); |
| if (cur_trans->in_commit) { |
| cur_trans->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; |
| } |
| |
| trans->transaction->in_commit = 1; |
| trans->transaction->blocked = 1; |
| 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); |
| } |
| } |
| |
| if (now < cur_trans->start_time || now - cur_trans->start_time < 1) |
| should_grow = 1; |
| |
| 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 if (should_grow) |
| timeout = 1; |
| |
| mutex_unlock(&root->fs_info->trans_mutex); |
| |
| if (flush_on_commit || snap_pending) { |
| btrfs_start_delalloc_inodes(root, 1); |
| ret = btrfs_wait_ordered_extents(root, 0, 1); |
| BUG_ON(ret); |
| } |
| |
| /* |
| * rename don't use btrfs_join_transaction, so, once we |
| * set the transaction to blocked above, we aren't going |
| * to get any new ordered operations. We can safely run |
| * it here and no for sure that nothing new will be added |
| * to the list |
| */ |
| btrfs_run_ordered_operations(root, 1); |
| |
| smp_mb(); |
| if (cur_trans->num_writers > 1 || should_grow) |
| schedule_timeout(timeout); |
| |
| mutex_lock(&root->fs_info->trans_mutex); |
| finish_wait(&cur_trans->writer_wait, &wait); |
| } while (cur_trans->num_writers > 1 || |
| (should_grow && cur_trans->num_joined != joined)); |
| |
| ret = create_pending_snapshots(trans, root->fs_info); |
| BUG_ON(ret); |
| |
| ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1); |
| 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); |
| |
| ret = commit_fs_roots(trans, root); |
| BUG_ON(ret); |
| |
| /* commit_fs_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); |
| |
| ret = commit_cowonly_roots(trans, root); |
| BUG_ON(ret); |
| |
| btrfs_prepare_extent_commit(trans, root); |
| |
| 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_root_node(&root->fs_info->tree_root->root_item, |
| root->fs_info->tree_root->node); |
| switch_commit_root(root->fs_info->tree_root); |
| |
| btrfs_set_root_node(&root->fs_info->chunk_root->root_item, |
| root->fs_info->chunk_root->node); |
| switch_commit_root(root->fs_info->chunk_root); |
| |
| update_super_roots(root); |
| |
| 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)); |
| |
| trans->transaction->blocked = 0; |
| |
| 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, 0); |
| |
| /* |
| * 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); |
| |
| 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); |
| |
| mutex_unlock(&root->fs_info->trans_mutex); |
| |
| if (current->journal_info == trans) |
| current->journal_info = NULL; |
| |
| kmem_cache_free(btrfs_trans_handle_cachep, trans); |
| |
| if (current != root->fs_info->transaction_kthread) |
| btrfs_run_delayed_iputs(root); |
| |
| return ret; |
| } |
| |
| /* |
| * interface function to delete all the snapshots we have scheduled for deletion |
| */ |
| int btrfs_clean_old_snapshots(struct btrfs_root *root) |
| { |
| LIST_HEAD(list); |
| struct btrfs_fs_info *fs_info = root->fs_info; |
| |
| mutex_lock(&fs_info->trans_mutex); |
| list_splice_init(&fs_info->dead_roots, &list); |
| mutex_unlock(&fs_info->trans_mutex); |
| |
| while (!list_empty(&list)) { |
| root = list_entry(list.next, struct btrfs_root, root_list); |
| list_del(&root->root_list); |
| |
| if (btrfs_header_backref_rev(root->node) < |
| BTRFS_MIXED_BACKREF_REV) |
| btrfs_drop_snapshot(root, 0); |
| else |
| btrfs_drop_snapshot(root, 1); |
| } |
| return 0; |
| } |