/* * 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 <linux/uuid.h> #include "ctree.h" #include "disk-io.h" #include "transaction.h" #include "locking.h" #include "tree-log.h" #include "inode-map.h" #include "volumes.h" #include "dev-replace.h" #include "qgroup.h" #define BTRFS_ROOT_TRANS_TAG 0 static unsigned int btrfs_blocked_trans_types[TRANS_STATE_MAX] = { [TRANS_STATE_RUNNING] = 0U, [TRANS_STATE_BLOCKED] = (__TRANS_USERSPACE | __TRANS_START), [TRANS_STATE_COMMIT_START] = (__TRANS_USERSPACE | __TRANS_START | __TRANS_ATTACH), [TRANS_STATE_COMMIT_DOING] = (__TRANS_USERSPACE | __TRANS_START | __TRANS_ATTACH | __TRANS_JOIN), [TRANS_STATE_UNBLOCKED] = (__TRANS_USERSPACE | __TRANS_START | __TRANS_ATTACH | __TRANS_JOIN | __TRANS_JOIN_NOLOCK), [TRANS_STATE_COMPLETED] = (__TRANS_USERSPACE | __TRANS_START | __TRANS_ATTACH | __TRANS_JOIN | __TRANS_JOIN_NOLOCK), }; void btrfs_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(!RB_EMPTY_ROOT(&transaction->delayed_refs.href_root)); while (!list_empty(&transaction->pending_chunks)) { struct extent_map *em; em = list_first_entry(&transaction->pending_chunks, struct extent_map, list); list_del_init(&em->list); free_extent_map(em); } kmem_cache_free(btrfs_transaction_cachep, transaction); } } static noinline void switch_commit_roots(struct btrfs_transaction *trans, struct btrfs_fs_info *fs_info) { struct btrfs_root *root, *tmp; down_write(&fs_info->commit_root_sem); list_for_each_entry_safe(root, tmp, &trans->switch_commits, dirty_list) { list_del_init(&root->dirty_list); free_extent_buffer(root->commit_root); root->commit_root = btrfs_root_node(root); if (is_fstree(root->objectid)) btrfs_unpin_free_ino(root); } up_write(&fs_info->commit_root_sem); } static inline void extwriter_counter_inc(struct btrfs_transaction *trans, unsigned int type) { if (type & TRANS_EXTWRITERS) atomic_inc(&trans->num_extwriters); } static inline void extwriter_counter_dec(struct btrfs_transaction *trans, unsigned int type) { if (type & TRANS_EXTWRITERS) atomic_dec(&trans->num_extwriters); } static inline void extwriter_counter_init(struct btrfs_transaction *trans, unsigned int type) { atomic_set(&trans->num_extwriters, ((type & TRANS_EXTWRITERS) ? 1 : 0)); } static inline int extwriter_counter_read(struct btrfs_transaction *trans) { return atomic_read(&trans->num_extwriters); } /* * either allocate a new transaction or hop into the existing one */ static noinline int join_transaction(struct btrfs_root *root, unsigned int type) { struct btrfs_transaction *cur_trans; struct btrfs_fs_info *fs_info = root->fs_info; spin_lock(&fs_info->trans_lock); loop: /* The file system has been taken offline. No new transactions. */ if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state)) { spin_unlock(&fs_info->trans_lock); return -EROFS; } cur_trans = fs_info->running_transaction; if (cur_trans) { if (cur_trans->aborted) { spin_unlock(&fs_info->trans_lock); return cur_trans->aborted; } if (btrfs_blocked_trans_types[cur_trans->state] & type) { spin_unlock(&fs_info->trans_lock); return -EBUSY; } atomic_inc(&cur_trans->use_count); atomic_inc(&cur_trans->num_writers); extwriter_counter_inc(cur_trans, type); spin_unlock(&fs_info->trans_lock); return 0; } spin_unlock(&fs_info->trans_lock); /* * If we are ATTACH, we just want to catch the current transaction, * and commit it. If there is no transaction, just return ENOENT. */ if (type == TRANS_ATTACH) return -ENOENT; /* * JOIN_NOLOCK only happens during the transaction commit, so * it is impossible that ->running_transaction is NULL */ BUG_ON(type == TRANS_JOIN_NOLOCK); cur_trans = kmem_cache_alloc(btrfs_transaction_cachep, GFP_NOFS); if (!cur_trans) return -ENOMEM; spin_lock(&fs_info->trans_lock); if (fs_info->running_transaction) { /* * someone started a transaction after we unlocked. Make sure * to redo the checks above */ kmem_cache_free(btrfs_transaction_cachep, cur_trans); goto loop; } else if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state)) { spin_unlock(&fs_info->trans_lock); kmem_cache_free(btrfs_transaction_cachep, cur_trans); return -EROFS; } atomic_set(&cur_trans->num_writers, 1); extwriter_counter_init(cur_trans, type); init_waitqueue_head(&cur_trans->writer_wait); init_waitqueue_head(&cur_trans->commit_wait); cur_trans->state = TRANS_STATE_RUNNING; /* * 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->start_time = get_seconds(); cur_trans->delayed_refs.href_root = RB_ROOT; atomic_set(&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; /* * although the tree mod log is per file system and not per transaction, * the log must never go across transaction boundaries. */ smp_mb(); if (!list_empty(&fs_info->tree_mod_seq_list)) WARN(1, KERN_ERR "BTRFS: tree_mod_seq_list not empty when " "creating a fresh transaction\n"); if (!RB_EMPTY_ROOT(&fs_info->tree_mod_log)) WARN(1, KERN_ERR "BTRFS: tree_mod_log rb tree not empty when " "creating a fresh transaction\n"); atomic64_set(&fs_info->tree_mod_seq, 0); spin_lock_init(&cur_trans->delayed_refs.lock); INIT_LIST_HEAD(&cur_trans->pending_snapshots); INIT_LIST_HEAD(&cur_trans->pending_chunks); INIT_LIST_HEAD(&cur_trans->switch_commits); list_add_tail(&cur_trans->list, &fs_info->trans_list); extent_io_tree_init(&cur_trans->dirty_pages, fs_info->btree_inode->i_mapping); fs_info->generation++; cur_trans->transid = fs_info->generation; fs_info->running_transaction = cur_trans; cur_trans->aborted = 0; spin_unlock(&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 (test_bit(BTRFS_ROOT_REF_COWS, &root->state) && 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 */ set_bit(BTRFS_ROOT_IN_TRANS_SETUP, &root->state); /* 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_mb__before_atomic(); clear_bit(BTRFS_ROOT_IN_TRANS_SETUP, &root->state); } return 0; } int btrfs_record_root_in_trans(struct btrfs_trans_handle *trans, struct btrfs_root *root) { if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state)) return 0; /* * see record_root_in_trans for comments about IN_TRANS_SETUP usage * and barriers */ smp_rmb(); if (root->last_trans == trans->transid && !test_bit(BTRFS_ROOT_IN_TRANS_SETUP, &root->state)) return 0; mutex_lock(&root->fs_info->reloc_mutex); record_root_in_trans(trans, root); mutex_unlock(&root->fs_info->reloc_mutex); return 0; } static inline int is_transaction_blocked(struct btrfs_transaction *trans) { return (trans->state >= TRANS_STATE_BLOCKED && trans->state < TRANS_STATE_UNBLOCKED && !trans->aborted); } /* 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 && is_transaction_blocked(cur_trans)) { atomic_inc(&cur_trans->use_count); spin_unlock(&root->fs_info->trans_lock); wait_event(root->fs_info->transaction_wait, cur_trans->state >= TRANS_STATE_UNBLOCKED || cur_trans->aborted); btrfs_put_transaction(cur_trans); } else { spin_unlock(&root->fs_info->trans_lock); } } 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 inline bool need_reserve_reloc_root(struct btrfs_root *root) { if (!root->fs_info->reloc_ctl || !test_bit(BTRFS_ROOT_REF_COWS, &root->state) || root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID || root->reloc_root) return false; return true; } static struct btrfs_trans_handle * start_transaction(struct btrfs_root *root, u64 num_items, unsigned int type, enum btrfs_reserve_flush_enum flush) { struct btrfs_trans_handle *h; struct btrfs_transaction *cur_trans; u64 num_bytes = 0; u64 qgroup_reserved = 0; bool reloc_reserved = false; int ret; /* Send isn't supposed to start transactions. */ ASSERT(current->journal_info != (void *)BTRFS_SEND_TRANS_STUB); if (test_bit(BTRFS_FS_STATE_ERROR, &root->fs_info->fs_state)) return ERR_PTR(-EROFS); if (current->journal_info) { WARN_ON(type & TRANS_EXTWRITERS); h = current->journal_info; h->use_count++; WARN_ON(h->use_count > 2); 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) { if (root->fs_info->quota_enabled && is_fstree(root->root_key.objectid)) { qgroup_reserved = num_items * root->nodesize; ret = btrfs_qgroup_reserve(root, qgroup_reserved); if (ret) return ERR_PTR(ret); } num_bytes = btrfs_calc_trans_metadata_size(root, num_items); /* * Do the reservation for the relocation root creation */ if (unlikely(need_reserve_reloc_root(root))) { num_bytes += root->nodesize; reloc_reserved = true; } ret = btrfs_block_rsv_add(root, &root->fs_info->trans_block_rsv, num_bytes, flush); if (ret) goto reserve_fail; } again: h = kmem_cache_alloc(btrfs_trans_handle_cachep, GFP_NOFS); if (!h) { ret = -ENOMEM; goto alloc_fail; } /* * If we are JOIN_NOLOCK we're already committing a transaction and * waiting on this guy, so we don't need to do the sb_start_intwrite * because we're already holding a ref. We need this because we could * have raced in and did an fsync() on a file which can kick a commit * and then we deadlock with somebody doing a freeze. * * If we are ATTACH, it means we just want to catch the current * transaction and commit it, so we needn't do sb_start_intwrite(). */ if (type & __TRANS_FREEZABLE) sb_start_intwrite(root->fs_info->sb); if (may_wait_transaction(root, type)) wait_current_trans(root); do { ret = join_transaction(root, type); if (ret == -EBUSY) { wait_current_trans(root); if (unlikely(type == TRANS_ATTACH)) ret = -ENOENT; } } while (ret == -EBUSY); if (ret < 0) { /* We must get the transaction if we are JOIN_NOLOCK. */ BUG_ON(type == TRANS_JOIN_NOLOCK); goto join_fail; } 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->root = root; h->delayed_ref_updates = 0; h->use_count = 1; h->adding_csums = 0; h->block_rsv = NULL; h->orig_rsv = NULL; h->aborted = 0; h->qgroup_reserved = 0; h->delayed_ref_elem.seq = 0; h->type = type; h->allocating_chunk = false; h->reloc_reserved = false; h->sync = false; INIT_LIST_HEAD(&h->qgroup_ref_list); INIT_LIST_HEAD(&h->new_bgs); smp_mb(); if (cur_trans->state >= TRANS_STATE_BLOCKED && may_wait_transaction(root, type)) { current->journal_info = h; 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; h->reloc_reserved = reloc_reserved; } h->qgroup_reserved = qgroup_reserved; got_it: btrfs_record_root_in_trans(h, root); if (!current->journal_info && type != TRANS_USERSPACE) current->journal_info = h; return h; join_fail: if (type & __TRANS_FREEZABLE) sb_end_intwrite(root->fs_info->sb); kmem_cache_free(btrfs_trans_handle_cachep, h); alloc_fail: if (num_bytes) btrfs_block_rsv_release(root, &root->fs_info->trans_block_rsv, num_bytes); reserve_fail: if (qgroup_reserved) btrfs_qgroup_free(root, qgroup_reserved); return ERR_PTR(ret); } struct btrfs_trans_handle *btrfs_start_transaction(struct btrfs_root *root, int num_items) { return start_transaction(root, num_items, TRANS_START, BTRFS_RESERVE_FLUSH_ALL); } struct btrfs_trans_handle *btrfs_start_transaction_lflush( struct btrfs_root *root, int num_items) { return start_transaction(root, num_items, TRANS_START, BTRFS_RESERVE_FLUSH_LIMIT); } struct btrfs_trans_handle *btrfs_join_transaction(struct btrfs_root *root) { return start_transaction(root, 0, TRANS_JOIN, 0); } struct btrfs_trans_handle *btrfs_join_transaction_nolock(struct btrfs_root *root) { return start_transaction(root, 0, TRANS_JOIN_NOLOCK, 0); } struct btrfs_trans_handle *btrfs_start_ioctl_transaction(struct btrfs_root *root) { return start_transaction(root, 0, TRANS_USERSPACE, 0); } /* * btrfs_attach_transaction() - catch the running transaction * * It is used when we want to commit the current the transaction, but * don't want to start a new one. * * Note: If this function return -ENOENT, it just means there is no * running transaction. But it is possible that the inactive transaction * is still in the memory, not fully on disk. If you hope there is no * inactive transaction in the fs when -ENOENT is returned, you should * invoke * btrfs_attach_transaction_barrier() */ struct btrfs_trans_handle *btrfs_attach_transaction(struct btrfs_root *root) { return start_transaction(root, 0, TRANS_ATTACH, 0); } /* * btrfs_attach_transaction_barrier() - catch the running transaction * * It is similar to the above function, the differentia is this one * will wait for all the inactive transactions until they fully * complete. */ struct btrfs_trans_handle * btrfs_attach_transaction_barrier(struct btrfs_root *root) { struct btrfs_trans_handle *trans; trans = start_transaction(root, 0, TRANS_ATTACH, 0); if (IS_ERR(trans) && PTR_ERR(trans) == -ENOENT) btrfs_wait_for_commit(root, 0); return trans; } /* 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->state == TRANS_STATE_COMPLETED); } int btrfs_wait_for_commit(struct btrfs_root *root, u64 transid) { struct btrfs_transaction *cur_trans = NULL, *t; int ret = 0; if (transid) { if (transid <= root->fs_info->last_trans_committed) goto out; ret = -EINVAL; /* 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); ret = 0; break; } if (t->transid > transid) { ret = 0; break; } } spin_unlock(&root->fs_info->trans_lock); /* The specified transaction doesn't exist */ if (!cur_trans) goto out; } 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->state >= TRANS_STATE_COMMIT_START) { if (t->state == TRANS_STATE_COMPLETED) 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); btrfs_put_transaction(cur_trans); 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) { if (root->fs_info->global_block_rsv.space_info->full && btrfs_check_space_for_delayed_refs(trans, root)) return 1; return !!btrfs_block_rsv_check(root, &root->fs_info->global_block_rsv, 5); } int btrfs_should_end_transaction(struct btrfs_trans_handle *trans, struct btrfs_root *root) { struct btrfs_transaction *cur_trans = trans->transaction; int updates; int err; smp_mb(); if (cur_trans->state >= TRANS_STATE_BLOCKED || cur_trans->delayed_refs.flushing) return 1; 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; } 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; unsigned long cur = trans->delayed_ref_updates; int lock = (trans->type != TRANS_JOIN_NOLOCK); int err = 0; int must_run_delayed_refs = 0; if (trans->use_count > 1) { trans->use_count--; trans->block_rsv = trans->orig_rsv; return 0; } btrfs_trans_release_metadata(trans, root); trans->block_rsv = NULL; if (!list_empty(&trans->new_bgs)) btrfs_create_pending_block_groups(trans, root); trans->delayed_ref_updates = 0; if (!trans->sync) { must_run_delayed_refs = btrfs_should_throttle_delayed_refs(trans, root); cur = max_t(unsigned long, cur, 32); /* * don't make the caller wait if they are from a NOLOCK * or ATTACH transaction, it will deadlock with commit */ if (must_run_delayed_refs == 1 && (trans->type & (__TRANS_JOIN_NOLOCK | __TRANS_ATTACH))) must_run_delayed_refs = 2; } if (trans->qgroup_reserved) { /* * the same root has to be passed here between start_transaction * and end_transaction. Subvolume quota depends on this. */ btrfs_qgroup_free(trans->root, trans->qgroup_reserved); trans->qgroup_reserved = 0; } btrfs_trans_release_metadata(trans, root); trans->block_rsv = NULL; if (!list_empty(&trans->new_bgs)) btrfs_create_pending_block_groups(trans, root); if (lock && !atomic_read(&root->fs_info->open_ioctl_trans) && should_end_transaction(trans, root) && ACCESS_ONCE(cur_trans->state) == TRANS_STATE_RUNNING) { spin_lock(&info->trans_lock); if (cur_trans->state == TRANS_STATE_RUNNING) cur_trans->state = TRANS_STATE_BLOCKED; spin_unlock(&info->trans_lock); } if (lock && ACCESS_ONCE(cur_trans->state) == TRANS_STATE_BLOCKED) { if (throttle) return btrfs_commit_transaction(trans, root); else wake_up_process(info->transaction_kthread); } if (trans->type & __TRANS_FREEZABLE) sb_end_intwrite(root->fs_info->sb); WARN_ON(cur_trans != info->running_transaction); WARN_ON(atomic_read(&cur_trans->num_writers) < 1); atomic_dec(&cur_trans->num_writers); extwriter_counter_dec(cur_trans, trans->type); smp_mb(); if (waitqueue_active(&cur_trans->writer_wait)) wake_up(&cur_trans->writer_wait); btrfs_put_transaction(cur_trans); if (current->journal_info == trans) current->journal_info = NULL; if (throttle) btrfs_run_delayed_iputs(root); if (trans->aborted || test_bit(BTRFS_FS_STATE_ERROR, &root->fs_info->fs_state)) { wake_up_process(info->transaction_kthread); err = -EIO; } assert_qgroups_uptodate(trans); kmem_cache_free(btrfs_trans_handle_cachep, trans); if (must_run_delayed_refs) { btrfs_async_run_delayed_refs(root, cur, must_run_delayed_refs == 1); } return err; } 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 err = 0; int werr = 0; struct address_space *mapping = root->fs_info->btree_inode->i_mapping; struct extent_state *cached_state = NULL; u64 start = 0; u64 end; while (!find_first_extent_bit(dirty_pages, start, &start, &end, mark, &cached_state)) { convert_extent_bit(dirty_pages, start, end, EXTENT_NEED_WAIT, mark, &cached_state, GFP_NOFS); cached_state = NULL; 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; struct extent_state *cached_state = NULL; u64 start = 0; u64 end; while (!find_first_extent_bit(dirty_pages, start, &start, &end, EXTENT_NEED_WAIT, &cached_state)) { clear_extent_bit(dirty_pages, start, end, EXTENT_NEED_WAIT, 0, 0, &cached_state, 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 */ static int btrfs_write_and_wait_marked_extents(struct btrfs_root *root, struct extent_io_tree *dirty_pages, int mark) { int ret; int ret2; struct blk_plug plug; blk_start_plug(&plug); ret = btrfs_write_marked_extents(root, dirty_pages, mark); blk_finish_plug(&plug); 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; } 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; ret = btrfs_run_dev_stats(trans, root->fs_info); if (ret) return ret; ret = btrfs_run_dev_replace(trans, root->fs_info); if (ret) return ret; ret = btrfs_run_qgroups(trans, root->fs_info); if (ret) return ret; /* run_qgroups might have added some more refs */ 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); if (root != fs_info->extent_root) list_add_tail(&root->dirty_list, &trans->transaction->switch_commits); ret = update_cowonly_root(trans, root); if (ret) return ret; } list_add_tail(&fs_info->extent_root->dirty_list, &trans->transaction->switch_commits); btrfs_after_dev_replace_commit(fs_info); 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 */ void btrfs_add_dead_root(struct btrfs_root *root) { spin_lock(&root->fs_info->trans_lock); if (list_empty(&root->root_list)) list_add_tail(&root->root_list, &root->fs_info->dead_roots); spin_unlock(&root->fs_info->trans_lock); } /* * 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() */ clear_bit(BTRFS_ROOT_FORCE_COW, &root->state); smp_mb__after_atomic(); if (root->commit_root != root->node) { list_add_tail(&root->dirty_list, &trans->transaction->switch_commits); 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. * Every leaf in the btree is read and defragged. */ int btrfs_defrag_root(struct btrfs_root *root) { struct btrfs_fs_info *info = root->fs_info; struct btrfs_trans_handle *trans; int ret; if (test_and_set_bit(BTRFS_ROOT_DEFRAG_RUNNING, &root->state)) return 0; while (1) { trans = btrfs_start_transaction(root, 0); if (IS_ERR(trans)) return PTR_ERR(trans); ret = btrfs_defrag_leaves(trans, root); btrfs_end_transaction(trans, root); btrfs_btree_balance_dirty(info->tree_root); cond_resched(); if (btrfs_fs_closing(root->fs_info) || ret != -EAGAIN) break; if (btrfs_defrag_cancelled(root->fs_info)) { pr_debug("BTRFS: defrag_root cancelled\n"); ret = -EAGAIN; break; } } clear_bit(BTRFS_ROOT_DEFRAG_RUNNING, &root->state); return ret; } /* * new snapshots need to be created at a very specific time in the * transaction commit. This does the actual creation. * * Note: * If the error which may affect the commitment of the current transaction * happens, we should return the error number. If the error which just affect * the creation of the pending snapshots, just return 0. */ 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 btrfs_path *path; struct btrfs_dir_item *dir_item; struct dentry *dentry; struct extent_buffer *tmp; struct extent_buffer *old; struct timespec cur_time = CURRENT_TIME; int ret = 0; u64 to_reserve = 0; u64 index = 0; u64 objectid; u64 root_flags; uuid_le new_uuid; path = btrfs_alloc_path(); if (!path) { pending->error = -ENOMEM; return 0; } new_root_item = kmalloc(sizeof(*new_root_item), GFP_NOFS); if (!new_root_item) { pending->error = -ENOMEM; goto root_item_alloc_fail; } pending->error = btrfs_find_free_objectid(tree_root, &objectid); if (pending->error) goto no_free_objectid; btrfs_reloc_pre_snapshot(trans, pending, &to_reserve); if (to_reserve > 0) { pending->error = btrfs_block_rsv_add(root, &pending->block_rsv, to_reserve, BTRFS_RESERVE_NO_FLUSH); if (pending->error) goto no_free_objectid; } key.objectid = objectid; key.offset = (u64)-1; key.type = BTRFS_ROOT_ITEM_KEY; rsv = trans->block_rsv; trans->block_rsv = &pending->block_rsv; trans->bytes_reserved = trans->block_rsv->reserved; dentry = pending->dentry; parent_inode = pending->dir; 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 */ /* check if there is a file/dir which has the same name. */ dir_item = btrfs_lookup_dir_item(NULL, parent_root, path, btrfs_ino(parent_inode), dentry->d_name.name, dentry->d_name.len, 0); if (dir_item != NULL && !IS_ERR(dir_item)) { pending->error = -EEXIST; goto dir_item_existed; } else if (IS_ERR(dir_item)) { ret = PTR_ERR(dir_item); btrfs_abort_transaction(trans, root, ret); goto fail; } btrfs_release_path(path); /* * 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 */ btrfs_abort_transaction(trans, root, ret); 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); btrfs_set_root_generation_v2(new_root_item, trans->transid); uuid_le_gen(&new_uuid); memcpy(new_root_item->uuid, new_uuid.b, BTRFS_UUID_SIZE); memcpy(new_root_item->parent_uuid, root->root_item.uuid, BTRFS_UUID_SIZE); if (!(root_flags & BTRFS_ROOT_SUBVOL_RDONLY)) { memset(new_root_item->received_uuid, 0, sizeof(new_root_item->received_uuid)); memset(&new_root_item->stime, 0, sizeof(new_root_item->stime)); memset(&new_root_item->rtime, 0, sizeof(new_root_item->rtime)); btrfs_set_root_stransid(new_root_item, 0); btrfs_set_root_rtransid(new_root_item, 0); } btrfs_set_stack_timespec_sec(&new_root_item->otime, cur_time.tv_sec); btrfs_set_stack_timespec_nsec(&new_root_item->otime, cur_time.tv_nsec); btrfs_set_root_otransid(new_root_item, trans->transid); 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); btrfs_abort_transaction(trans, root, ret); goto fail; } 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) { btrfs_abort_transaction(trans, root, ret); goto fail; } /* * We need to flush delayed refs in order to make sure all of our quota * operations have been done before we call btrfs_qgroup_inherit. */ ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1); if (ret) { btrfs_abort_transaction(trans, root, ret); goto fail; } ret = btrfs_qgroup_inherit(trans, fs_info, root->root_key.objectid, objectid, pending->inherit); if (ret) { btrfs_abort_transaction(trans, root, ret); goto fail; } /* see comments in should_cow_block() */ set_bit(BTRFS_ROOT_FORCE_COW, &root->state); 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) { btrfs_abort_transaction(trans, root, ret); goto fail; } /* * 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); if (ret) { btrfs_abort_transaction(trans, root, 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); btrfs_abort_transaction(trans, root, ret); goto fail; } ret = btrfs_reloc_post_snapshot(trans, pending); if (ret) { btrfs_abort_transaction(trans, root, ret); goto fail; } ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1); if (ret) { btrfs_abort_transaction(trans, root, ret); goto fail; } ret = btrfs_insert_dir_item(trans, parent_root, dentry->d_name.name, dentry->d_name.len, parent_inode, &key, BTRFS_FT_DIR, index); /* We have check then name at the beginning, so it is impossible. */ BUG_ON(ret == -EEXIST || ret == -EOVERFLOW); if (ret) { btrfs_abort_transaction(trans, root, ret); goto fail; } btrfs_i_size_write(parent_inode, parent_inode->i_size + dentry->d_name.len * 2); parent_inode->i_mtime = parent_inode->i_ctime = CURRENT_TIME; ret = btrfs_update_inode_fallback(trans, parent_root, parent_inode); if (ret) { btrfs_abort_transaction(trans, root, ret); goto fail; } ret = btrfs_uuid_tree_add(trans, fs_info->uuid_root, new_uuid.b, BTRFS_UUID_KEY_SUBVOL, objectid); if (ret) { btrfs_abort_transaction(trans, root, ret); goto fail; } if (!btrfs_is_empty_uuid(new_root_item->received_uuid)) { ret = btrfs_uuid_tree_add(trans, fs_info->uuid_root, new_root_item->received_uuid, BTRFS_UUID_KEY_RECEIVED_SUBVOL, objectid); if (ret && ret != -EEXIST) { btrfs_abort_transaction(trans, root, ret); goto fail; } } fail: pending->error = ret; dir_item_existed: trans->block_rsv = rsv; trans->bytes_reserved = 0; no_free_objectid: kfree(new_root_item); root_item_alloc_fail: btrfs_free_path(path); 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, *next; struct list_head *head = &trans->transaction->pending_snapshots; int ret = 0; list_for_each_entry_safe(pending, next, head, list) { list_del(&pending->list); ret = create_pending_snapshot(trans, fs_info, pending); if (ret) break; } return ret; } 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; if (root->fs_info->update_uuid_tree_gen) super->uuid_tree_generation = root_item->generation; } int btrfs_transaction_in_commit(struct btrfs_fs_info *info) { struct btrfs_transaction *trans; int ret = 0; spin_lock(&info->trans_lock); trans = info->running_transaction; if (trans) ret = (trans->state >= TRANS_STATE_COMMIT_START); spin_unlock(&info->trans_lock); return ret; } int btrfs_transaction_blocked(struct btrfs_fs_info *info) { struct btrfs_transaction *trans; int ret = 0; spin_lock(&info->trans_lock); trans = info->running_transaction; if (trans) ret = is_transaction_blocked(trans); 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->state >= TRANS_STATE_COMMIT_START || trans->aborted); } /* * 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->state >= TRANS_STATE_UNBLOCKED || trans->aborted); } /* * 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 work_struct work; }; static void do_async_commit(struct work_struct *work) { struct btrfs_async_commit *ac = container_of(work, struct btrfs_async_commit, work); /* * We've got freeze protection passed with the transaction. * Tell lockdep about it. */ if (ac->newtrans->type & __TRANS_FREEZABLE) rwsem_acquire_read( &ac->root->fs_info->sb->s_writers.lock_map[SB_FREEZE_FS-1], 0, 1, _THIS_IP_); current->journal_info = ac->newtrans; 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_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); /* * Tell lockdep we've released the freeze rwsem, since the * async commit thread will be the one to unlock it. */ if (ac->newtrans->type & __TRANS_FREEZABLE) rwsem_release( &root->fs_info->sb->s_writers.lock_map[SB_FREEZE_FS-1], 1, _THIS_IP_); schedule_work(&ac->work); /* 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; btrfs_put_transaction(cur_trans); return 0; } static void cleanup_transaction(struct btrfs_trans_handle *trans, struct btrfs_root *root, int err) { struct btrfs_transaction *cur_trans = trans->transaction; DEFINE_WAIT(wait); WARN_ON(trans->use_count > 1); btrfs_abort_transaction(trans, root, err); spin_lock(&root->fs_info->trans_lock); /* * If the transaction is removed from the list, it means this * transaction has been committed successfully, so it is impossible * to call the cleanup function. */ BUG_ON(list_empty(&cur_trans->list)); list_del_init(&cur_trans->list); if (cur_trans == root->fs_info->running_transaction) { cur_trans->state = TRANS_STATE_COMMIT_DOING; spin_unlock(&root->fs_info->trans_lock); wait_event(cur_trans->writer_wait, atomic_read(&cur_trans->num_writers) == 1); spin_lock(&root->fs_info->trans_lock); } spin_unlock(&root->fs_info->trans_lock); btrfs_cleanup_one_transaction(trans->transaction, root); spin_lock(&root->fs_info->trans_lock); if (cur_trans == root->fs_info->running_transaction) root->fs_info->running_transaction = NULL; spin_unlock(&root->fs_info->trans_lock); if (trans->type & __TRANS_FREEZABLE) sb_end_intwrite(root->fs_info->sb); btrfs_put_transaction(cur_trans); btrfs_put_transaction(cur_trans); trace_btrfs_transaction_commit(root); if (current->journal_info == trans) current->journal_info = NULL; btrfs_scrub_cancel(root->fs_info); kmem_cache_free(btrfs_trans_handle_cachep, trans); } static inline int btrfs_start_delalloc_flush(struct btrfs_fs_info *fs_info) { if (btrfs_test_opt(fs_info->tree_root, FLUSHONCOMMIT)) return btrfs_start_delalloc_roots(fs_info, 1, -1); return 0; } static inline void btrfs_wait_delalloc_flush(struct btrfs_fs_info *fs_info) { if (btrfs_test_opt(fs_info->tree_root, FLUSHONCOMMIT)) btrfs_wait_ordered_roots(fs_info, -1); } int btrfs_commit_transaction(struct btrfs_trans_handle *trans, struct btrfs_root *root) { struct btrfs_transaction *cur_trans = trans->transaction; struct btrfs_transaction *prev_trans = NULL; int ret; /* Stop the commit early if ->aborted is set */ if (unlikely(ACCESS_ONCE(cur_trans->aborted))) { ret = cur_trans->aborted; btrfs_end_transaction(trans, root); return ret; } /* 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) { btrfs_end_transaction(trans, root); return ret; } btrfs_trans_release_metadata(trans, root); trans->block_rsv = NULL; if (trans->qgroup_reserved) { btrfs_qgroup_free(root, trans->qgroup_reserved); trans->qgroup_reserved = 0; } 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; smp_wmb(); if (!list_empty(&trans->new_bgs)) btrfs_create_pending_block_groups(trans, root); ret = btrfs_run_delayed_refs(trans, root, 0); if (ret) { btrfs_end_transaction(trans, root); return ret; } spin_lock(&root->fs_info->trans_lock); if (cur_trans->state >= TRANS_STATE_COMMIT_START) { spin_unlock(&root->fs_info->trans_lock); atomic_inc(&cur_trans->use_count); ret = btrfs_end_transaction(trans, root); wait_for_commit(root, cur_trans); btrfs_put_transaction(cur_trans); return ret; } cur_trans->state = TRANS_STATE_COMMIT_START; wake_up(&root->fs_info->transaction_blocked_wait); 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->state != TRANS_STATE_COMPLETED) { atomic_inc(&prev_trans->use_count); spin_unlock(&root->fs_info->trans_lock); wait_for_commit(root, prev_trans); btrfs_put_transaction(prev_trans); } else { spin_unlock(&root->fs_info->trans_lock); } } else { spin_unlock(&root->fs_info->trans_lock); } extwriter_counter_dec(cur_trans, trans->type); ret = btrfs_start_delalloc_flush(root->fs_info); if (ret) goto cleanup_transaction; ret = btrfs_run_delayed_items(trans, root); if (ret) goto cleanup_transaction; wait_event(cur_trans->writer_wait, extwriter_counter_read(cur_trans) == 0); /* some pending stuffs might be added after the previous flush. */ ret = btrfs_run_delayed_items(trans, root); if (ret) goto cleanup_transaction; btrfs_wait_delalloc_flush(root->fs_info); btrfs_scrub_pause(root); /* * 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 * COMMIT_DOING so make sure to wait for num_writers to == 1 again. */ spin_lock(&root->fs_info->trans_lock); cur_trans->state = TRANS_STATE_COMMIT_DOING; spin_unlock(&root->fs_info->trans_lock); wait_event(cur_trans->writer_wait, atomic_read(&cur_trans->num_writers) == 1); /* ->aborted might be set after the previous check, so check it */ if (unlikely(ACCESS_ONCE(cur_trans->aborted))) { ret = cur_trans->aborted; goto scrub_continue; } /* * 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); /* * We needn't worry about the delayed items because we will * deal with them in create_pending_snapshot(), which is the * core function of the snapshot creation. */ ret = create_pending_snapshots(trans, root->fs_info); if (ret) { mutex_unlock(&root->fs_info->reloc_mutex); goto scrub_continue; } /* * We insert the dir indexes of the snapshots and update the inode * of the snapshots' parents after the snapshot creation, so there * are some delayed items which are not dealt with. Now deal with * them. * * We needn't worry that this operation will corrupt the snapshots, * because all the tree which are snapshoted will be forced to COW * the nodes and leaves. */ ret = btrfs_run_delayed_items(trans, root); if (ret) { mutex_unlock(&root->fs_info->reloc_mutex); goto scrub_continue; } ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1); if (ret) { mutex_unlock(&root->fs_info->reloc_mutex); goto scrub_continue; } /* * 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_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 scrub_continue; } /* * Since the transaction is done, we should set the inode map cache flag * before any other comming transaction. */ if (btrfs_test_opt(root, CHANGE_INODE_CACHE)) btrfs_set_opt(root->fs_info->mount_opt, INODE_MAP_CACHE); else btrfs_clear_opt(root->fs_info->mount_opt, INODE_MAP_CACHE); /* 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 scrub_continue; } /* * The tasks which save the space cache and inode cache may also * update ->aborted, check it. */ if (unlikely(ACCESS_ONCE(cur_trans->aborted))) { ret = cur_trans->aborted; mutex_unlock(&root->fs_info->tree_log_mutex); mutex_unlock(&root->fs_info->reloc_mutex); goto scrub_continue; } 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); list_add_tail(&root->fs_info->tree_root->dirty_list, &cur_trans->switch_commits); btrfs_set_root_node(&root->fs_info->chunk_root->root_item, root->fs_info->chunk_root->node); list_add_tail(&root->fs_info->chunk_root->dirty_list, &cur_trans->switch_commits); switch_commit_roots(cur_trans, root->fs_info); assert_qgroups_uptodate(trans); update_super_roots(root); 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)); spin_lock(&root->fs_info->trans_lock); cur_trans->state = TRANS_STATE_UNBLOCKED; root->fs_info->running_transaction = NULL; 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 scrub_continue; } ret = write_ctree_super(trans, root, 0); if (ret) { mutex_unlock(&root->fs_info->tree_log_mutex); goto scrub_continue; } /* * 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); root->fs_info->last_trans_committed = cur_trans->transid; /* * We needn't acquire the lock here because there is no other task * which can change it. */ cur_trans->state = TRANS_STATE_COMPLETED; 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); btrfs_put_transaction(cur_trans); btrfs_put_transaction(cur_trans); if (trans->type & __TRANS_FREEZABLE) sb_end_intwrite(root->fs_info->sb); 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; scrub_continue: btrfs_scrub_continue(root); cleanup_transaction: btrfs_trans_release_metadata(trans, root); trans->block_rsv = NULL; if (trans->qgroup_reserved) { btrfs_qgroup_free(root, trans->qgroup_reserved); trans->qgroup_reserved = 0; } btrfs_warn(root->fs_info, "Skipping commit of aborted transaction."); if (current->journal_info == trans) current->journal_info = NULL; cleanup_transaction(trans, root, ret); return ret; } /* * return < 0 if error * 0 if there are no more dead_roots at the time of call * 1 there are more to be processed, call me again * * The return value indicates there are certainly more snapshots to delete, but * if there comes a new one during processing, it may return 0. We don't mind, * because btrfs_commit_super will poke cleaner thread and it will process it a * few seconds later. */ int btrfs_clean_one_deleted_snapshot(struct btrfs_root *root) { int ret; struct btrfs_fs_info *fs_info = root->fs_info; spin_lock(&fs_info->trans_lock); if (list_empty(&fs_info->dead_roots)) { spin_unlock(&fs_info->trans_lock); return 0; } root = list_first_entry(&fs_info->dead_roots, struct btrfs_root, root_list); list_del_init(&root->root_list); spin_unlock(&fs_info->trans_lock); pr_debug("BTRFS: cleaner removing %llu\n", root->objectid); 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); return (ret < 0) ? 0 : 1; }