diff options
Diffstat (limited to 'fs/btrfs/transaction.c')
| -rw-r--r-- | fs/btrfs/transaction.c | 1539 |
1 files changed, 1539 insertions, 0 deletions
diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c new file mode 100644 index 00000000..36422254 --- /dev/null +++ b/fs/btrfs/transaction.c @@ -0,0 +1,1539 @@ +/* + * 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" +#include "inode-map.h" + +#define BTRFS_ROOT_TRANS_TAG 0 + +void put_transaction(struct btrfs_transaction *transaction) +{ + WARN_ON(atomic_read(&transaction->use_count) == 0); + if (atomic_dec_and_test(&transaction->use_count)) { + BUG_ON(!list_empty(&transaction->list)); + WARN_ON(transaction->delayed_refs.root.rb_node); + WARN_ON(!list_empty(&transaction->delayed_refs.seq_head)); + 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, int nofail) +{ + struct btrfs_transaction *cur_trans; + + spin_lock(&root->fs_info->trans_lock); +loop: + /* The file system has been taken offline. No new transactions. */ + if (root->fs_info->fs_state & BTRFS_SUPER_FLAG_ERROR) { + spin_unlock(&root->fs_info->trans_lock); + return -EROFS; + } + + if (root->fs_info->trans_no_join) { + if (!nofail) { + spin_unlock(&root->fs_info->trans_lock); + return -EBUSY; + } + } + + cur_trans = root->fs_info->running_transaction; + if (cur_trans) { + if (cur_trans->aborted) { + spin_unlock(&root->fs_info->trans_lock); + return cur_trans->aborted; + } + atomic_inc(&cur_trans->use_count); + atomic_inc(&cur_trans->num_writers); + cur_trans->num_joined++; + spin_unlock(&root->fs_info->trans_lock); + return 0; + } + spin_unlock(&root->fs_info->trans_lock); + + cur_trans = kmem_cache_alloc(btrfs_transaction_cachep, GFP_NOFS); + if (!cur_trans) + return -ENOMEM; + + spin_lock(&root->fs_info->trans_lock); + if (root->fs_info->running_transaction) { + /* + * someone started a transaction after we unlocked. Make sure + * to redo the trans_no_join checks above + */ + kmem_cache_free(btrfs_transaction_cachep, cur_trans); + cur_trans = root->fs_info->running_transaction; + goto loop; + } + + atomic_set(&cur_trans->num_writers, 1); + cur_trans->num_joined = 0; + init_waitqueue_head(&cur_trans->writer_wait); + init_waitqueue_head(&cur_trans->commit_wait); + cur_trans->in_commit = 0; + cur_trans->blocked = 0; + /* + * One for this trans handle, one so it will live on until we + * commit the transaction. + */ + atomic_set(&cur_trans->use_count, 2); + 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; + cur_trans->delayed_refs.seq = 1; + init_waitqueue_head(&cur_trans->delayed_refs.seq_wait); + spin_lock_init(&cur_trans->commit_lock); + spin_lock_init(&cur_trans->delayed_refs.lock); + INIT_LIST_HEAD(&cur_trans->delayed_refs.seq_head); + + 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); + root->fs_info->generation++; + cur_trans->transid = root->fs_info->generation; + root->fs_info->running_transaction = cur_trans; + cur_trans->aborted = 0; + spin_unlock(&root->fs_info->trans_lock); + + 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 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); + + /* + * see below for in_trans_setup usage rules + * we have the reloc mutex held now, so there + * is only one writer in this function + */ + root->in_trans_setup = 1; + + /* make sure readers find in_trans_setup before + * they find our root->last_trans update + */ + smp_wmb(); + + spin_lock(&root->fs_info->fs_roots_radix_lock); + if (root->last_trans == trans->transid) { + spin_unlock(&root->fs_info->fs_roots_radix_lock); + return 0; + } + radix_tree_tag_set(&root->fs_info->fs_roots_radix, + (unsigned long)root->root_key.objectid, + BTRFS_ROOT_TRANS_TAG); + spin_unlock(&root->fs_info->fs_roots_radix_lock); + root->last_trans = trans->transid; + + /* this is pretty tricky. We don't want to + * take the relocation lock in btrfs_record_root_in_trans + * unless we're really doing the first setup for this root in + * this transaction. + * + * Normally we'd use root->last_trans as a flag to decide + * if we want to take the expensive mutex. + * + * But, we have to set root->last_trans before we + * init the relocation root, otherwise, we trip over warnings + * in ctree.c. The solution used here is to flag ourselves + * with root->in_trans_setup. When this is 1, we're still + * fixing up the reloc trees and everyone must wait. + * + * When this is zero, they can trust root->last_trans and fly + * through btrfs_record_root_in_trans without having to take the + * lock. smp_wmb() makes sure that all the writes above are + * done before we pop in the zero below + */ + btrfs_init_reloc_root(trans, root); + smp_wmb(); + root->in_trans_setup = 0; + } + return 0; +} + + +int btrfs_record_root_in_trans(struct btrfs_trans_handle *trans, + struct btrfs_root *root) +{ + if (!root->ref_cows) + return 0; + + /* + * see record_root_in_trans for comments about in_trans_setup usage + * and barriers + */ + smp_rmb(); + if (root->last_trans == trans->transid && + !root->in_trans_setup) + return 0; + + mutex_lock(&root->fs_info->reloc_mutex); + record_root_in_trans(trans, root); + mutex_unlock(&root->fs_info->reloc_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; + + spin_lock(&root->fs_info->trans_lock); + cur_trans = root->fs_info->running_transaction; + if (cur_trans && cur_trans->blocked) { + atomic_inc(&cur_trans->use_count); + spin_unlock(&root->fs_info->trans_lock); + + wait_event(root->fs_info->transaction_wait, + !cur_trans->blocked); + put_transaction(cur_trans); + } else { + spin_unlock(&root->fs_info->trans_lock); + } +} + +enum btrfs_trans_type { + TRANS_START, + TRANS_JOIN, + TRANS_USERSPACE, + TRANS_JOIN_NOLOCK, +}; + +static int may_wait_transaction(struct btrfs_root *root, int type) +{ + if (root->fs_info->log_root_recovering) + return 0; + + if (type == TRANS_USERSPACE) + return 1; + + if (type == TRANS_START && + !atomic_read(&root->fs_info->open_ioctl_trans)) + 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; + u64 num_bytes = 0; + int ret; + + if (root->fs_info->fs_state & BTRFS_SUPER_FLAG_ERROR) + return ERR_PTR(-EROFS); + + if (current->journal_info) { + WARN_ON(type != TRANS_JOIN && type != TRANS_JOIN_NOLOCK); + h = current->journal_info; + h->use_count++; + h->orig_rsv = h->block_rsv; + h->block_rsv = NULL; + goto got_it; + } + + /* + * Do the reservation before we join the transaction so we can do all + * the appropriate flushing if need be. + */ + if (num_items > 0 && root != root->fs_info->chunk_root) { + num_bytes = btrfs_calc_trans_metadata_size(root, num_items); + ret = btrfs_block_rsv_add(root, + &root->fs_info->trans_block_rsv, + num_bytes); + if (ret) + return ERR_PTR(ret); + } +again: + h = kmem_cache_alloc(btrfs_trans_handle_cachep, GFP_NOFS); + if (!h) + return ERR_PTR(-ENOMEM); + + if (may_wait_transaction(root, type)) + wait_current_trans(root); + + do { + ret = join_transaction(root, type == TRANS_JOIN_NOLOCK); + if (ret == -EBUSY) + wait_current_trans(root); + } while (ret == -EBUSY); + + if (ret < 0) { + kmem_cache_free(btrfs_trans_handle_cachep, h); + return ERR_PTR(ret); + } + + cur_trans = root->fs_info->running_transaction; + + h->transid = cur_trans->transid; + h->transaction = cur_trans; + h->blocks_used = 0; + h->bytes_reserved = 0; + h->delayed_ref_updates = 0; + h->use_count = 1; + h->block_rsv = NULL; + h->orig_rsv = NULL; + h->aborted = 0; + + smp_mb(); + if (cur_trans->blocked && may_wait_transaction(root, type)) { + btrfs_commit_transaction(h, root); + goto again; + } + + if (num_bytes) { + trace_btrfs_space_reservation(root->fs_info, "transaction", + h->transid, num_bytes, 1); + h->block_rsv = &root->fs_info->trans_block_rsv; + h->bytes_reserved = num_bytes; + } + +got_it: + btrfs_record_root_in_trans(h, root); + + 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) +{ + return start_transaction(root, 0, TRANS_JOIN); +} + +struct btrfs_trans_handle *btrfs_join_transaction_nolock(struct btrfs_root *root) +{ + return start_transaction(root, 0, TRANS_JOIN_NOLOCK); +} + +struct btrfs_trans_handle *btrfs_start_ioctl_transaction(struct btrfs_root *root) +{ + return start_transaction(root, 0, TRANS_USERSPACE); +} + +/* wait for a transaction commit to be fully complete */ +static noinline void wait_for_commit(struct btrfs_root *root, + struct btrfs_transaction *commit) +{ + wait_event(commit->commit_wait, commit->commit_done); +} + +int btrfs_wait_for_commit(struct btrfs_root *root, u64 transid) +{ + struct btrfs_transaction *cur_trans = NULL, *t; + int ret; + + ret = 0; + if (transid) { + if (transid <= root->fs_info->last_trans_committed) + goto out; + + /* find specified transaction */ + spin_lock(&root->fs_info->trans_lock); + list_for_each_entry(t, &root->fs_info->trans_list, list) { + if (t->transid == transid) { + cur_trans = t; + atomic_inc(&cur_trans->use_count); + break; + } + if (t->transid > transid) + break; + } + spin_unlock(&root->fs_info->trans_lock); + ret = -EINVAL; + if (!cur_trans) + goto out; /* bad transid */ + } else { + /* find newest transaction that is committing | committed */ + spin_lock(&root->fs_info->trans_lock); + list_for_each_entry_reverse(t, &root->fs_info->trans_list, + list) { + if (t->in_commit) { + if (t->commit_done) + break; + cur_trans = t; + atomic_inc(&cur_trans->use_count); + break; + } + } + spin_unlock(&root->fs_info->trans_lock); + if (!cur_trans) + goto out; /* nothing committing|committed */ + } + + wait_for_commit(root, cur_trans); + + put_transaction(cur_trans); + ret = 0; +out: + return ret; +} + +void btrfs_throttle(struct btrfs_root *root) +{ + if (!atomic_read(&root->fs_info->open_ioctl_trans)) + wait_current_trans(root); +} + +static int should_end_transaction(struct btrfs_trans_handle *trans, + struct btrfs_root *root) +{ + int ret; + + ret = btrfs_block_rsv_check(root, &root->fs_info->global_block_rsv, 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; + struct btrfs_block_rsv *rsv = trans->block_rsv; + int updates; + int err; + + smp_mb(); + if (cur_trans->blocked || cur_trans->delayed_refs.flushing) + return 1; + + /* + * We need to do this in case we're deleting csums so the global block + * rsv get's used instead of the csum block rsv. + */ + trans->block_rsv = NULL; + + updates = trans->delayed_ref_updates; + trans->delayed_ref_updates = 0; + if (updates) { + err = btrfs_run_delayed_refs(trans, root, updates); + if (err) /* Error code will also eval true */ + return err; + } + + trans->block_rsv = rsv; + + return should_end_transaction(trans, root); +} + +static int __btrfs_end_transaction(struct btrfs_trans_handle *trans, + struct btrfs_root *root, int throttle, int lock) +{ + struct btrfs_transaction *cur_trans = trans->transaction; + struct btrfs_fs_info *info = root->fs_info; + int count = 0; + int err = 0; + + if (--trans->use_count) { + trans->block_rsv = trans->orig_rsv; + return 0; + } + + btrfs_trans_release_metadata(trans, root); + trans->block_rsv = NULL; + while (count < 2) { + 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; + btrfs_run_delayed_refs(trans, root, cur); + } else { + break; + } + count++; + } + + if (lock && !atomic_read(&root->fs_info->open_ioctl_trans) && + should_end_transaction(trans, root)) { + trans->transaction->blocked = 1; + smp_wmb(); + } + + if (lock && cur_trans->blocked && !cur_trans->in_commit) { + if (throttle) { + /* + * We may race with somebody else here so end up having + * to call end_transaction on ourselves again, so inc + * our use_count. + */ + trans->use_count++; + return btrfs_commit_transaction(trans, root); + } else { + wake_up_process(info->transaction_kthread); + } + } + + WARN_ON(cur_trans != info->running_transaction); + WARN_ON(atomic_read(&cur_trans->num_writers) < 1); + atomic_dec(&cur_trans->num_writers); + + smp_mb(); + if (waitqueue_active(&cur_trans->writer_wait)) + wake_up(&cur_trans->writer_wait); + put_transaction(cur_trans); + + if (current->journal_info == trans) + current->journal_info = NULL; + + if (throttle) + btrfs_run_delayed_iputs(root); + + if (trans->aborted || + root->fs_info->fs_state & BTRFS_SUPER_FLAG_ERROR) { + err = -EIO; + } + + memset(trans, 0, sizeof(*trans)); + kmem_cache_free(btrfs_trans_handle_cachep, trans); + return err; +} + +int btrfs_end_transaction(struct btrfs_trans_handle *trans, + struct btrfs_root *root) +{ + int ret; + + ret = __btrfs_end_transaction(trans, root, 0, 1); + if (ret) + return ret; + return 0; +} + +int btrfs_end_transaction_throttle(struct btrfs_trans_handle *trans, + struct btrfs_root *root) +{ + int ret; + + ret = __btrfs_end_transaction(trans, root, 1, 1); + if (ret) + return ret; + return 0; +} + +int btrfs_end_transaction_nolock(struct btrfs_trans_handle *trans, + struct btrfs_root *root) +{ + int ret; + + ret = __btrfs_end_transaction(trans, root, 0, 0); + if (ret) + return ret; + return 0; +} + +int btrfs_end_transaction_dmeta(struct btrfs_trans_handle *trans, + struct btrfs_root *root) +{ + return __btrfs_end_transaction(trans, root, 1, 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 err = 0; + int werr = 0; + struct address_space *mapping = root->fs_info->btree_inode->i_mapping; + u64 start = 0; + u64 end; + + while (!find_first_extent_bit(dirty_pages, start, &start, &end, + mark)) { + convert_extent_bit(dirty_pages, start, end, EXTENT_NEED_WAIT, mark, + GFP_NOFS); + err = filemap_fdatawrite_range(mapping, start, end); + if (err) + werr = err; + cond_resched(); + start = end + 1; + } + 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 err = 0; + int werr = 0; + struct address_space *mapping = root->fs_info->btree_inode->i_mapping; + u64 start = 0; + u64 end; + + while (!find_first_extent_bit(dirty_pages, start, &start, &end, + EXTENT_NEED_WAIT)) { + clear_extent_bits(dirty_pages, start, end, EXTENT_NEED_WAIT, GFP_NOFS); + err = filemap_fdatawait_range(mapping, start, end); + if (err) + werr = err; + cond_resched(); + start = end + 1; + } + 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); + + if (ret) + return ret; + if (ret2) + return ret2; + return 0; +} + +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); + if (ret) + return ret; + + old_root_used = btrfs_root_used(&root->root_item); + ret = btrfs_write_dirty_block_groups(trans, root); + if (ret) + return ret; + } + + if (root != root->fs_info->extent_root) + switch_commit_root(root); + + return 0; +} + +/* + * update all the cowonly tree roots on disk + * + * The error handling in this function may not be obvious. Any of the + * failures will cause the file system to go offline. We still need + * to clean up the delayed refs. + */ +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); + if (ret) + return ret; + + eb = btrfs_lock_root_node(fs_info->tree_root); + ret = btrfs_cow_block(trans, fs_info->tree_root, eb, NULL, + 0, &eb); + btrfs_tree_unlock(eb); + free_extent_buffer(eb); + + if (ret) + return ret; + + ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1); + if (ret) + return 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); + + ret = update_cowonly_root(trans, root); + if (ret) + return ret; + } + + 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) +{ + spin_lock(&root->fs_info->trans_lock); + list_add(&root->root_list, &root->fs_info->dead_roots); + spin_unlock(&root->fs_info->trans_lock); + 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; + + spin_lock(&fs_info->fs_roots_radix_lock); + 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); + spin_unlock(&fs_info->fs_roots_radix_lock); + + btrfs_free_log(trans, root); + btrfs_update_reloc_root(trans, root); + btrfs_orphan_commit_root(trans, root); + + btrfs_save_ino_cache(root, trans); + + /* see comments in should_cow_block() */ + root->force_cow = 0; + smp_wmb(); + + if (root->commit_root != root->node) { + mutex_lock(&root->fs_commit_mutex); + switch_commit_root(root); + btrfs_unpin_free_ino(root); + mutex_unlock(&root->fs_commit_mutex); + + btrfs_set_root_node(&root->root_item, + root->node); + } + + err = btrfs_update_root(trans, fs_info->tree_root, + &root->root_key, + &root->root_item); + spin_lock(&fs_info->fs_roots_radix_lock); + if (err) + break; + } + } + spin_unlock(&fs_info->fs_roots_radix_lock); + 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 (btrfs_fs_closing(root->fs_info) || ret != -EAGAIN) + break; + } + root->defrag_running = 0; + 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 btrfs_root *parent_root; + struct btrfs_block_rsv *rsv; + struct inode *parent_inode; + struct dentry *parent; + struct dentry *dentry; + struct extent_buffer *tmp; + struct extent_buffer *old; + int ret; + u64 to_reserve = 0; + u64 index = 0; + u64 objectid; + u64 root_flags; + + rsv = trans->block_rsv; + + new_root_item = kmalloc(sizeof(*new_root_item), GFP_NOFS); + if (!new_root_item) { + ret = pending->error = -ENOMEM; + goto fail; + } + + ret = btrfs_find_free_objectid(tree_root, &objectid); + if (ret) { + pending->error = ret; + goto fail; + } + + btrfs_reloc_pre_snapshot(trans, pending, &to_reserve); + + if (to_reserve > 0) { + ret = btrfs_block_rsv_add_noflush(root, &pending->block_rsv, + to_reserve); + 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 = dget_parent(dentry); + parent_inode = 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); /* -ENOMEM */ + ret = btrfs_insert_dir_item(trans, parent_root, + dentry->d_name.name, dentry->d_name.len, + parent_inode, &key, + BTRFS_FT_DIR, index); + if (ret == -EEXIST) { + pending->error = -EEXIST; + dput(parent); + goto fail; + } else if (ret) { + goto abort_trans_dput; + } + + btrfs_i_size_write(parent_inode, parent_inode->i_size + + dentry->d_name.len * 2); + ret = btrfs_update_inode(trans, parent_root, parent_inode); + if (ret) + goto abort_trans_dput; + + /* + * pull in the delayed directory update + * and the delayed inode item + * otherwise we corrupt the FS during + * snapshot + */ + ret = btrfs_run_delayed_items(trans, root); + if (ret) { /* Transaction aborted */ + dput(parent); + goto fail; + } + + 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)); + btrfs_check_and_init_root_item(new_root_item); + + root_flags = btrfs_root_flags(new_root_item); + if (pending->readonly) + root_flags |= BTRFS_ROOT_SUBVOL_RDONLY; + else + root_flags &= ~BTRFS_ROOT_SUBVOL_RDONLY; + btrfs_set_root_flags(new_root_item, root_flags); + + old = btrfs_lock_root_node(root); + ret = btrfs_cow_block(trans, root, old, NULL, 0, &old); + if (ret) { + btrfs_tree_unlock(old); + free_extent_buffer(old); + goto abort_trans_dput; + } + + btrfs_set_lock_blocking(old); + + ret = btrfs_copy_root(trans, root, old, &tmp, objectid); + /* clean up in any case */ + btrfs_tree_unlock(old); + free_extent_buffer(old); + if (ret) + goto abort_trans_dput; + + /* see comments in should_cow_block() */ + root->force_cow = 1; + smp_wmb(); + + 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); + if (ret) + goto abort_trans_dput; + + /* + * insert root back/forward references + */ + ret = btrfs_add_root_ref(trans, tree_root, objectid, + parent_root->root_key.objectid, + btrfs_ino(parent_inode), index, + dentry->d_name.name, dentry->d_name.len); + dput(parent); + if (ret) + goto fail; + + key.offset = (u64)-1; + pending->snap = btrfs_read_fs_root_no_name(root->fs_info, &key); + if (IS_ERR(pending->snap)) { + ret = PTR_ERR(pending->snap); + goto abort_trans; + } + + ret = btrfs_reloc_post_snapshot(trans, pending); + if (ret) + goto abort_trans; + ret = 0; +fail: + kfree(new_root_item); + trans->block_rsv = rsv; + btrfs_block_rsv_release(root, &pending->block_rsv, (u64)-1); + return ret; + +abort_trans_dput: + dput(parent); +abort_trans: + btrfs_abort_transaction(trans, root, ret); + goto fail; +} + +/* + * 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; + + list_for_each_entry(pending, head, list) + create_pending_snapshot(trans, fs_info, pending); + 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; + if (btrfs_test_opt(root, SPACE_CACHE)) + super->cache_generation = root_item->generation; +} + +int btrfs_transaction_in_commit(struct btrfs_fs_info *info) +{ + int ret = 0; + spin_lock(&info->trans_lock); + if (info->running_transaction) + ret = info->running_transaction->in_commit; + spin_unlock(&info->trans_lock); + return ret; +} + +int btrfs_transaction_blocked(struct btrfs_fs_info *info) +{ + int ret = 0; + spin_lock(&info->trans_lock); + if (info->running_transaction) + ret = info->running_transaction->blocked; + spin_unlock(&info->trans_lock); + return ret; +} + +/* + * wait for the current transaction commit to start and block subsequent + * transaction joins + */ +static void wait_current_trans_commit_start(struct btrfs_root *root, + struct btrfs_transaction *trans) +{ + wait_event(root->fs_info->transaction_blocked_wait, trans->in_commit); +} + +/* + * wait for the current transaction to start and then become unblocked. + * caller holds ref. + */ +static void wait_current_trans_commit_start_and_unblock(struct btrfs_root *root, + struct btrfs_transaction *trans) +{ + wait_event(root->fs_info->transaction_wait, + trans->commit_done || (trans->in_commit && !trans->blocked)); +} + +/* + * commit transactions asynchronously. once btrfs_commit_transaction_async + * returns, any subsequent transaction will not be allowed to join. + */ +struct btrfs_async_commit { + struct btrfs_trans_handle *newtrans; + struct btrfs_root *root; + struct delayed_work work; +}; + +static void do_async_commit(struct work_struct *work) +{ + struct btrfs_async_commit *ac = + container_of(work, struct btrfs_async_commit, work.work); + + btrfs_commit_transaction(ac->newtrans, ac->root); + kfree(ac); +} + +int btrfs_commit_transaction_async(struct btrfs_trans_handle *trans, + struct btrfs_root *root, + int wait_for_unblock) +{ + struct btrfs_async_commit *ac; + struct btrfs_transaction *cur_trans; + + ac = kmalloc(sizeof(*ac), GFP_NOFS); + if (!ac) + return -ENOMEM; + + INIT_DELAYED_WORK(&ac->work, do_async_commit); + ac->root = root; + ac->newtrans = btrfs_join_transaction(root); + if (IS_ERR(ac->newtrans)) { + int err = PTR_ERR(ac->newtrans); + kfree(ac); + return err; + } + + /* take transaction reference */ + cur_trans = trans->transaction; + atomic_inc(&cur_trans->use_count); + + btrfs_end_transaction(trans, root); + schedule_delayed_work(&ac->work, 0); + + /* wait for transaction to start and unblock */ + if (wait_for_unblock) + wait_current_trans_commit_start_and_unblock(root, cur_trans); + else + wait_current_trans_commit_start(root, cur_trans); + + if (current->journal_info == trans) + current->journal_info = NULL; + + put_transaction(cur_trans); + return 0; +} + + +static void cleanup_transaction(struct btrfs_trans_handle *trans, + struct btrfs_root *root) +{ + struct btrfs_transaction *cur_trans = trans->transaction; + + WARN_ON(trans->use_count > 1); + + spin_lock(&root->fs_info->trans_lock); + list_del_init(&cur_trans->list); + spin_unlock(&root->fs_info->trans_lock); + + btrfs_cleanup_one_transaction(trans->transaction, root); + + put_transaction(cur_trans); + put_transaction(cur_trans); + + trace_btrfs_transaction_commit(root); + + btrfs_scrub_continue(root); + + if (current->journal_info == trans) + current->journal_info = NULL; + + kmem_cache_free(btrfs_trans_handle_cachep, trans); +} + +/* + * btrfs_transaction state sequence: + * in_commit = 0, blocked = 0 (initial) + * in_commit = 1, blocked = 1 + * blocked = 0 + * commit_done = 1 + */ +int btrfs_commit_transaction(struct btrfs_trans_handle *trans, + struct btrfs_root *root) +{ + unsigned long joined = 0; + struct btrfs_transaction *cur_trans = trans->transaction; + struct btrfs_transaction *prev_trans = NULL; + DEFINE_WAIT(wait); + int ret = -EIO; + int should_grow = 0; + unsigned long now = get_seconds(); + int flush_on_commit = btrfs_test_opt(root, FLUSHONCOMMIT); + + btrfs_run_ordered_operations(root, 0); + + btrfs_trans_release_metadata(trans, root); + trans->block_rsv = NULL; + + if (cur_trans->aborted) + goto cleanup_transaction; + + /* 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); + if (ret) + goto cleanup_transaction; + + 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); + if (ret) + goto cleanup_transaction; + + spin_lock(&cur_trans->commit_lock); + if (cur_trans->in_commit) { + spin_unlock(&cur_trans->commit_lock); + atomic_inc(&cur_trans->use_count); + ret = btrfs_end_transaction(trans, root); + + wait_for_commit(root, cur_trans); + + put_transaction(cur_trans); + + return ret; + } + + trans->transaction->in_commit = 1; + trans->transaction->blocked = 1; + spin_unlock(&cur_trans->commit_lock); + wake_up(&root->fs_info->transaction_blocked_wait); + + spin_lock(&root->fs_info->trans_lock); + 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) { + atomic_inc(&prev_trans->use_count); + spin_unlock(&root->fs_info->trans_lock); + + wait_for_commit(root, prev_trans); + + put_transaction(prev_trans); + } else { + spin_unlock(&root->fs_info->trans_lock); + } + } else { + spin_unlock(&root->fs_info->trans_lock); + } + + 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); + + if (flush_on_commit || snap_pending) { + btrfs_start_delalloc_inodes(root, 1); + btrfs_wait_ordered_extents(root, 0, 1); + } + + ret = btrfs_run_delayed_items(trans, root); + if (ret) + goto cleanup_transaction; + + /* + * 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); + + prepare_to_wait(&cur_trans->writer_wait, &wait, + TASK_UNINTERRUPTIBLE); + + if (atomic_read(&cur_trans->num_writers) > 1) + schedule_timeout(MAX_SCHEDULE_TIMEOUT); + else if (should_grow) + schedule_timeout(1); + + finish_wait(&cur_trans->writer_wait, &wait); + } while (atomic_read(&cur_trans->num_writers) > 1 || + (should_grow && cur_trans->num_joined != joined)); + + /* + * Ok now we need to make sure to block out any other joins while we + * commit the transaction. We could have started a join before setting + * no_join so make sure to wait for num_writers to == 1 again. + */ + spin_lock(&root->fs_info->trans_lock); + root->fs_info->trans_no_join = 1; + spin_unlock(&root->fs_info->trans_lock); + wait_event(cur_trans->writer_wait, + atomic_read(&cur_trans->num_writers) == 1); + + /* + * the reloc mutex makes sure that we stop + * the balancing code from coming in and moving + * extents around in the middle of the commit + */ + mutex_lock(&root->fs_info->reloc_mutex); + + ret = btrfs_run_delayed_items(trans, root); + if (ret) { + mutex_unlock(&root->fs_info->reloc_mutex); + goto cleanup_transaction; + } + + ret = create_pending_snapshots(trans, root->fs_info); + if (ret) { + mutex_unlock(&root->fs_info->reloc_mutex); + goto cleanup_transaction; + } + + ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1); + if (ret) { + mutex_unlock(&root->fs_info->reloc_mutex); + goto cleanup_transaction; + } + + /* + * make sure none of the code above managed to slip in a + * delayed item + */ + btrfs_assert_delayed_root_empty(root); + + WARN_ON(cur_trans != trans->transaction); + + btrfs_scrub_pause(root); + /* 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); + if (ret) { + mutex_unlock(&root->fs_info->tree_log_mutex); + mutex_unlock(&root->fs_info->reloc_mutex); + goto cleanup_transaction; + } + + /* 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); + if (ret) { + mutex_unlock(&root->fs_info->tree_log_mutex); + mutex_unlock(&root->fs_info->reloc_mutex); + goto cleanup_transaction; + } + + btrfs_prepare_extent_commit(trans, root); + + cur_trans = root->fs_info->running_transaction; + + 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; + spin_lock(&root->fs_info->trans_lock); + root->fs_info->running_transaction = NULL; + root->fs_info->trans_no_join = 0; + spin_unlock(&root->fs_info->trans_lock); + mutex_unlock(&root->fs_info->reloc_mutex); + + wake_up(&root->fs_info->transaction_wait); + + ret = btrfs_write_and_wait_transaction(trans, root); + if (ret) { + btrfs_error(root->fs_info, ret, + "Error while writing out transaction."); + mutex_unlock(&root->fs_info->tree_log_mutex); + goto cleanup_transaction; + } + + ret = write_ctree_super(trans, root, 0); + if (ret) { + mutex_unlock(&root->fs_info->tree_log_mutex); + goto cleanup_transaction; + } + + /* + * 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); + + cur_trans->commit_done = 1; + + root->fs_info->last_trans_committed = cur_trans->transid; + + wake_up(&cur_trans->commit_wait); + + spin_lock(&root->fs_info->trans_lock); + list_del_init(&cur_trans->list); + spin_unlock(&root->fs_info->trans_lock); + + put_transaction(cur_trans); + put_transaction(cur_trans); + + trace_btrfs_transaction_commit(root); + + btrfs_scrub_continue(root); + + 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; + +cleanup_transaction: + btrfs_printk(root->fs_info, "Skipping commit of aborted transaction.\n"); +// WARN_ON(1); + if (current->journal_info == trans) + current->journal_info = NULL; + cleanup_transaction(trans, 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; + + spin_lock(&fs_info->trans_lock); + list_splice_init(&fs_info->dead_roots, &list); + spin_unlock(&fs_info->trans_lock); + + while (!list_empty(&list)) { + int ret; + + root = list_entry(list.next, struct btrfs_root, root_list); + list_del(&root->root_list); + + btrfs_kill_all_delayed_nodes(root); + + if (btrfs_header_backref_rev(root->node) < + BTRFS_MIXED_BACKREF_REV) + ret = btrfs_drop_snapshot(root, NULL, 0, 0); + else + ret =btrfs_drop_snapshot(root, NULL, 1, 0); + BUG_ON(ret < 0); + } + return 0; +} |