// SPDX-License-Identifier: GPL-2.0 /* * Copyright (C) 2007 Oracle. All rights reserved. */ #include #include #include #include #include #include #include #include #include #include "misc.h" #include "ctree.h" #include "disk-io.h" #include "transaction.h" #include "locking.h" #include "tree-log.h" #include "volumes.h" #include "dev-replace.h" #include "qgroup.h" #include "block-group.h" #include "space-info.h" #include "fs.h" #include "accessors.h" #include "extent-tree.h" #include "root-tree.h" #include "dir-item.h" #include "uuid-tree.h" #include "ioctl.h" #include "relocation.h" #include "scrub.h" static struct kmem_cache *btrfs_trans_handle_cachep; /* * Transaction states and transitions * * No running transaction (fs tree blocks are not modified) * | * | To next stage: * | Call start_transaction() variants. Except btrfs_join_transaction_nostart(). * V * Transaction N [[TRANS_STATE_RUNNING]] * | * | New trans handles can be attached to transaction N by calling all * | start_transaction() variants. * | * | To next stage: * | Call btrfs_commit_transaction() on any trans handle attached to * | transaction N * V * Transaction N [[TRANS_STATE_COMMIT_PREP]] * | * | If there are simultaneous calls to btrfs_commit_transaction() one will win * | the race and the rest will wait for the winner to commit the transaction. * | * | The winner will wait for previous running transaction to completely finish * | if there is one. * | * Transaction N [[TRANS_STATE_COMMIT_START]] * | * | Then one of the following happens: * | - Wait for all other trans handle holders to release. * | The btrfs_commit_transaction() caller will do the commit work. * | - Wait for current transaction to be committed by others. * | Other btrfs_commit_transaction() caller will do the commit work. * | * | At this stage, only btrfs_join_transaction*() variants can attach * | to this running transaction. * | All other variants will wait for current one to finish and attach to * | transaction N+1. * | * | To next stage: * | Caller is chosen to commit transaction N, and all other trans handle * | haven been released. * V * Transaction N [[TRANS_STATE_COMMIT_DOING]] * | * | The heavy lifting transaction work is started. * | From running delayed refs (modifying extent tree) to creating pending * | snapshots, running qgroups. * | In short, modify supporting trees to reflect modifications of subvolume * | trees. * | * | At this stage, all start_transaction() calls will wait for this * | transaction to finish and attach to transaction N+1. * | * | To next stage: * | Until all supporting trees are updated. * V * Transaction N [[TRANS_STATE_UNBLOCKED]] * | Transaction N+1 * | All needed trees are modified, thus we only [[TRANS_STATE_RUNNING]] * | need to write them back to disk and update | * | super blocks. | * | | * | At this stage, new transaction is allowed to | * | start. | * | All new start_transaction() calls will be | * | attached to transid N+1. | * | | * | To next stage: | * | Until all tree blocks are super blocks are | * | written to block devices | * V | * Transaction N [[TRANS_STATE_COMPLETED]] V * All tree blocks and super blocks are written. Transaction N+1 * This transaction is finished and all its [[TRANS_STATE_COMMIT_START]] * data structures will be cleaned up. | Life goes on */ static const unsigned int btrfs_blocked_trans_types[TRANS_STATE_MAX] = { [TRANS_STATE_RUNNING] = 0U, [TRANS_STATE_COMMIT_PREP] = 0U, [TRANS_STATE_COMMIT_START] = (__TRANS_START | __TRANS_ATTACH), [TRANS_STATE_COMMIT_DOING] = (__TRANS_START | __TRANS_ATTACH | __TRANS_JOIN | __TRANS_JOIN_NOSTART), [TRANS_STATE_UNBLOCKED] = (__TRANS_START | __TRANS_ATTACH | __TRANS_JOIN | __TRANS_JOIN_NOLOCK | __TRANS_JOIN_NOSTART), [TRANS_STATE_SUPER_COMMITTED] = (__TRANS_START | __TRANS_ATTACH | __TRANS_JOIN | __TRANS_JOIN_NOLOCK | __TRANS_JOIN_NOSTART), [TRANS_STATE_COMPLETED] = (__TRANS_START | __TRANS_ATTACH | __TRANS_JOIN | __TRANS_JOIN_NOLOCK | __TRANS_JOIN_NOSTART), }; void btrfs_put_transaction(struct btrfs_transaction *transaction) { WARN_ON(refcount_read(&transaction->use_count) == 0); if (refcount_dec_and_test(&transaction->use_count)) { BUG_ON(!list_empty(&transaction->list)); WARN_ON(!xa_empty(&transaction->delayed_refs.head_refs)); WARN_ON(!xa_empty(&transaction->delayed_refs.dirty_extents)); if (transaction->delayed_refs.pending_csums) btrfs_err(transaction->fs_info, "pending csums is %llu", transaction->delayed_refs.pending_csums); /* * If any block groups are found in ->deleted_bgs then it's * because the transaction was aborted and a commit did not * happen (things failed before writing the new superblock * and calling btrfs_finish_extent_commit()), so we can not * discard the physical locations of the block groups. */ while (!list_empty(&transaction->deleted_bgs)) { struct btrfs_block_group *cache; cache = list_first_entry(&transaction->deleted_bgs, struct btrfs_block_group, bg_list); list_del_init(&cache->bg_list); btrfs_unfreeze_block_group(cache); btrfs_put_block_group(cache); } WARN_ON(!list_empty(&transaction->dev_update_list)); kfree(transaction); } } static noinline void switch_commit_roots(struct btrfs_trans_handle *trans) { struct btrfs_transaction *cur_trans = trans->transaction; struct btrfs_fs_info *fs_info = trans->fs_info; struct btrfs_root *root, *tmp; /* * At this point no one can be using this transaction to modify any tree * and no one can start another transaction to modify any tree either. */ ASSERT(cur_trans->state == TRANS_STATE_COMMIT_DOING); down_write(&fs_info->commit_root_sem); if (test_bit(BTRFS_FS_RELOC_RUNNING, &fs_info->flags)) fs_info->last_reloc_trans = trans->transid; list_for_each_entry_safe(root, tmp, &cur_trans->switch_commits, dirty_list) { list_del_init(&root->dirty_list); free_extent_buffer(root->commit_root); root->commit_root = btrfs_root_node(root); extent_io_tree_release(&root->dirty_log_pages); btrfs_qgroup_clean_swapped_blocks(root); } /* We can free old roots now. */ spin_lock(&cur_trans->dropped_roots_lock); while (!list_empty(&cur_trans->dropped_roots)) { root = list_first_entry(&cur_trans->dropped_roots, struct btrfs_root, root_list); list_del_init(&root->root_list); spin_unlock(&cur_trans->dropped_roots_lock); btrfs_free_log(trans, root); btrfs_drop_and_free_fs_root(fs_info, root); spin_lock(&cur_trans->dropped_roots_lock); } spin_unlock(&cur_trans->dropped_roots_lock); 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); } /* * To be called after doing the chunk btree updates right after allocating a new * chunk (after btrfs_chunk_alloc_add_chunk_item() is called), when removing a * chunk after all chunk btree updates and after finishing the second phase of * chunk allocation (btrfs_create_pending_block_groups()) in case some block * group had its chunk item insertion delayed to the second phase. */ void btrfs_trans_release_chunk_metadata(struct btrfs_trans_handle *trans) { struct btrfs_fs_info *fs_info = trans->fs_info; if (!trans->chunk_bytes_reserved) return; btrfs_block_rsv_release(fs_info, &fs_info->chunk_block_rsv, trans->chunk_bytes_reserved, NULL); trans->chunk_bytes_reserved = 0; } /* * either allocate a new transaction or hop into the existing one */ static noinline int join_transaction(struct btrfs_fs_info *fs_info, unsigned int type) { struct btrfs_transaction *cur_trans; spin_lock(&fs_info->trans_lock); loop: /* The file system has been taken offline. No new transactions. */ if (BTRFS_FS_ERROR(fs_info)) { spin_unlock(&fs_info->trans_lock); return -EROFS; } cur_trans = fs_info->running_transaction; if (cur_trans) { if (TRANS_ABORTED(cur_trans)) { 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; } refcount_inc(&cur_trans->use_count); atomic_inc(&cur_trans->num_writers); extwriter_counter_inc(cur_trans, type); spin_unlock(&fs_info->trans_lock); btrfs_lockdep_acquire(fs_info, btrfs_trans_num_writers); btrfs_lockdep_acquire(fs_info, btrfs_trans_num_extwriters); return 0; } spin_unlock(&fs_info->trans_lock); /* * If we are ATTACH or TRANS_JOIN_NOSTART, we just want to catch the * current transaction, and commit it. If there is no transaction, just * return ENOENT. */ if (type == TRANS_ATTACH || type == TRANS_JOIN_NOSTART) 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 = kmalloc(sizeof(*cur_trans), GFP_NOFS); if (!cur_trans) return -ENOMEM; btrfs_lockdep_acquire(fs_info, btrfs_trans_num_writers); btrfs_lockdep_acquire(fs_info, btrfs_trans_num_extwriters); 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 */ btrfs_lockdep_release(fs_info, btrfs_trans_num_extwriters); btrfs_lockdep_release(fs_info, btrfs_trans_num_writers); kfree(cur_trans); goto loop; } else if (BTRFS_FS_ERROR(fs_info)) { spin_unlock(&fs_info->trans_lock); btrfs_lockdep_release(fs_info, btrfs_trans_num_extwriters); btrfs_lockdep_release(fs_info, btrfs_trans_num_writers); kfree(cur_trans); return -EROFS; } cur_trans->fs_info = fs_info; atomic_set(&cur_trans->pending_ordered, 0); init_waitqueue_head(&cur_trans->pending_wait); 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. */ refcount_set(&cur_trans->use_count, 2); cur_trans->flags = 0; cur_trans->start_time = ktime_get_seconds(); memset(&cur_trans->delayed_refs, 0, sizeof(cur_trans->delayed_refs)); xa_init(&cur_trans->delayed_refs.head_refs); xa_init(&cur_trans->delayed_refs.dirty_extents); /* * 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->dev_update_list); INIT_LIST_HEAD(&cur_trans->switch_commits); INIT_LIST_HEAD(&cur_trans->dirty_bgs); INIT_LIST_HEAD(&cur_trans->io_bgs); INIT_LIST_HEAD(&cur_trans->dropped_roots); mutex_init(&cur_trans->cache_write_mutex); spin_lock_init(&cur_trans->dirty_bgs_lock); INIT_LIST_HEAD(&cur_trans->deleted_bgs); spin_lock_init(&cur_trans->dropped_roots_lock); list_add_tail(&cur_trans->list, &fs_info->trans_list); extent_io_tree_init(fs_info, &cur_trans->dirty_pages, IO_TREE_TRANS_DIRTY_PAGES); extent_io_tree_init(fs_info, &cur_trans->pinned_extents, IO_TREE_FS_PINNED_EXTENTS); btrfs_set_fs_generation(fs_info, fs_info->generation + 1); 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 shareable 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, int force) { struct btrfs_fs_info *fs_info = root->fs_info; int ret = 0; if ((test_bit(BTRFS_ROOT_SHAREABLE, &root->state) && btrfs_get_root_last_trans(root) < trans->transid) || force) { WARN_ON(!force && 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(&fs_info->fs_roots_radix_lock); if (btrfs_get_root_last_trans(root) == trans->transid && !force) { spin_unlock(&fs_info->fs_roots_radix_lock); return 0; } radix_tree_tag_set(&fs_info->fs_roots_radix, (unsigned long)btrfs_root_id(root), BTRFS_ROOT_TRANS_TAG); spin_unlock(&fs_info->fs_roots_radix_lock); btrfs_set_root_last_trans(root, 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 */ ret = btrfs_init_reloc_root(trans, root); smp_mb__before_atomic(); clear_bit(BTRFS_ROOT_IN_TRANS_SETUP, &root->state); } return ret; } void btrfs_add_dropped_root(struct btrfs_trans_handle *trans, struct btrfs_root *root) { struct btrfs_fs_info *fs_info = root->fs_info; struct btrfs_transaction *cur_trans = trans->transaction; /* Add ourselves to the transaction dropped list */ spin_lock(&cur_trans->dropped_roots_lock); list_add_tail(&root->root_list, &cur_trans->dropped_roots); spin_unlock(&cur_trans->dropped_roots_lock); /* Make sure we don't try to update the root at commit time */ spin_lock(&fs_info->fs_roots_radix_lock); radix_tree_tag_clear(&fs_info->fs_roots_radix, (unsigned long)btrfs_root_id(root), BTRFS_ROOT_TRANS_TAG); spin_unlock(&fs_info->fs_roots_radix_lock); } int btrfs_record_root_in_trans(struct btrfs_trans_handle *trans, struct btrfs_root *root) { struct btrfs_fs_info *fs_info = root->fs_info; int ret; if (!test_bit(BTRFS_ROOT_SHAREABLE, &root->state)) return 0; /* * see record_root_in_trans for comments about IN_TRANS_SETUP usage * and barriers */ smp_rmb(); if (btrfs_get_root_last_trans(root) == trans->transid && !test_bit(BTRFS_ROOT_IN_TRANS_SETUP, &root->state)) return 0; mutex_lock(&fs_info->reloc_mutex); ret = record_root_in_trans(trans, root, 0); mutex_unlock(&fs_info->reloc_mutex); return ret; } static inline int is_transaction_blocked(struct btrfs_transaction *trans) { return (trans->state >= TRANS_STATE_COMMIT_START && trans->state < TRANS_STATE_UNBLOCKED && !TRANS_ABORTED(trans)); } /* 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_fs_info *fs_info) { struct btrfs_transaction *cur_trans; spin_lock(&fs_info->trans_lock); cur_trans = fs_info->running_transaction; if (cur_trans && is_transaction_blocked(cur_trans)) { refcount_inc(&cur_trans->use_count); spin_unlock(&fs_info->trans_lock); btrfs_might_wait_for_state(fs_info, BTRFS_LOCKDEP_TRANS_UNBLOCKED); wait_event(fs_info->transaction_wait, cur_trans->state >= TRANS_STATE_UNBLOCKED || TRANS_ABORTED(cur_trans)); btrfs_put_transaction(cur_trans); } else { spin_unlock(&fs_info->trans_lock); } } static int may_wait_transaction(struct btrfs_fs_info *fs_info, int type) { if (test_bit(BTRFS_FS_LOG_RECOVERING, &fs_info->flags)) return 0; if (type == TRANS_START) return 1; return 0; } static inline bool need_reserve_reloc_root(struct btrfs_root *root) { struct btrfs_fs_info *fs_info = root->fs_info; if (!fs_info->reloc_ctl || !test_bit(BTRFS_ROOT_SHAREABLE, &root->state) || btrfs_root_id(root) == BTRFS_TREE_RELOC_OBJECTID || root->reloc_root) return false; return true; } static int btrfs_reserve_trans_metadata(struct btrfs_fs_info *fs_info, enum btrfs_reserve_flush_enum flush, u64 num_bytes, u64 *delayed_refs_bytes) { struct btrfs_space_info *si = fs_info->trans_block_rsv.space_info; u64 bytes = num_bytes + *delayed_refs_bytes; int ret; /* * We want to reserve all the bytes we may need all at once, so we only * do 1 enospc flushing cycle per transaction start. */ ret = btrfs_reserve_metadata_bytes(fs_info, si, bytes, flush); /* * If we are an emergency flush, which can steal from the global block * reserve, then attempt to not reserve space for the delayed refs, as * we will consume space for them from the global block reserve. */ if (ret && flush == BTRFS_RESERVE_FLUSH_ALL_STEAL) { bytes -= *delayed_refs_bytes; *delayed_refs_bytes = 0; ret = btrfs_reserve_metadata_bytes(fs_info, si, bytes, flush); } return ret; } static struct btrfs_trans_handle * start_transaction(struct btrfs_root *root, unsigned int num_items, unsigned int type, enum btrfs_reserve_flush_enum flush, bool enforce_qgroups) { struct btrfs_fs_info *fs_info = root->fs_info; struct btrfs_block_rsv *delayed_refs_rsv = &fs_info->delayed_refs_rsv; struct btrfs_block_rsv *trans_rsv = &fs_info->trans_block_rsv; struct btrfs_trans_handle *h; struct btrfs_transaction *cur_trans; u64 num_bytes = 0; u64 qgroup_reserved = 0; u64 delayed_refs_bytes = 0; bool reloc_reserved = false; bool do_chunk_alloc = false; int ret; if (BTRFS_FS_ERROR(fs_info)) return ERR_PTR(-EROFS); if (current->journal_info) { WARN_ON(type & TRANS_EXTWRITERS); h = current->journal_info; refcount_inc(&h->use_count); WARN_ON(refcount_read(&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 && root != fs_info->chunk_root) { qgroup_reserved = num_items * fs_info->nodesize; /* * Use prealloc for now, as there might be a currently running * transaction that could free this reserved space prematurely * by committing. */ ret = btrfs_qgroup_reserve_meta_prealloc(root, qgroup_reserved, enforce_qgroups, false); if (ret) return ERR_PTR(ret); num_bytes = btrfs_calc_insert_metadata_size(fs_info, num_items); /* * If we plan to insert/update/delete "num_items" from a btree, * we will also generate delayed refs for extent buffers in the * respective btree paths, so reserve space for the delayed refs * that will be generated by the caller as it modifies btrees. * Try to reserve them to avoid excessive use of the global * block reserve. */ delayed_refs_bytes = btrfs_calc_delayed_ref_bytes(fs_info, num_items); /* * Do the reservation for the relocation root creation */ if (need_reserve_reloc_root(root)) { num_bytes += fs_info->nodesize; reloc_reserved = true; } ret = btrfs_reserve_trans_metadata(fs_info, flush, num_bytes, &delayed_refs_bytes); if (ret) goto reserve_fail; btrfs_block_rsv_add_bytes(trans_rsv, num_bytes, true); if (trans_rsv->space_info->force_alloc) do_chunk_alloc = true; } else if (num_items == 0 && flush == BTRFS_RESERVE_FLUSH_ALL && !btrfs_block_rsv_full(delayed_refs_rsv)) { /* * Some people call with btrfs_start_transaction(root, 0) * because they can be throttled, but have some other mechanism * for reserving space. We still want these guys to refill the * delayed block_rsv so just add 1 items worth of reservation * here. */ ret = btrfs_delayed_refs_rsv_refill(fs_info, flush); if (ret) goto reserve_fail; } again: h = kmem_cache_zalloc(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(fs_info->sb); if (may_wait_transaction(fs_info, type)) wait_current_trans(fs_info); do { ret = join_transaction(fs_info, type); if (ret == -EBUSY) { wait_current_trans(fs_info); if (unlikely(type == TRANS_ATTACH || type == TRANS_JOIN_NOSTART)) ret = -ENOENT; } } while (ret == -EBUSY); if (ret < 0) goto join_fail; cur_trans = fs_info->running_transaction; h->transid = cur_trans->transid; h->transaction = cur_trans; refcount_set(&h->use_count, 1); h->fs_info = root->fs_info; h->type = type; INIT_LIST_HEAD(&h->new_bgs); btrfs_init_metadata_block_rsv(fs_info, &h->delayed_rsv, BTRFS_BLOCK_RSV_DELOPS); smp_mb(); if (cur_trans->state >= TRANS_STATE_COMMIT_START && may_wait_transaction(fs_info, type)) { current->journal_info = h; btrfs_commit_transaction(h); goto again; } if (num_bytes) { trace_btrfs_space_reservation(fs_info, "transaction", h->transid, num_bytes, 1); h->block_rsv = trans_rsv; h->bytes_reserved = num_bytes; if (delayed_refs_bytes > 0) { trace_btrfs_space_reservation(fs_info, "local_delayed_refs_rsv", h->transid, delayed_refs_bytes, 1); h->delayed_refs_bytes_reserved = delayed_refs_bytes; btrfs_block_rsv_add_bytes(&h->delayed_rsv, delayed_refs_bytes, true); delayed_refs_bytes = 0; } h->reloc_reserved = reloc_reserved; } got_it: if (!current->journal_info) current->journal_info = h; /* * If the space_info is marked ALLOC_FORCE then we'll get upgraded to * ALLOC_FORCE the first run through, and then we won't allocate for * anybody else who races in later. We don't care about the return * value here. */ if (do_chunk_alloc && num_bytes) { u64 flags = h->block_rsv->space_info->flags; btrfs_chunk_alloc(h, btrfs_get_alloc_profile(fs_info, flags), CHUNK_ALLOC_NO_FORCE); } /* * btrfs_record_root_in_trans() needs to alloc new extents, and may * call btrfs_join_transaction() while we're also starting a * transaction. * * Thus it need to be called after current->journal_info initialized, * or we can deadlock. */ ret = btrfs_record_root_in_trans(h, root); if (ret) { /* * The transaction handle is fully initialized and linked with * other structures so it needs to be ended in case of errors, * not just freed. */ btrfs_end_transaction(h); goto reserve_fail; } /* * Now that we have found a transaction to be a part of, convert the * qgroup reservation from prealloc to pertrans. A different transaction * can't race in and free our pertrans out from under us. */ if (qgroup_reserved) btrfs_qgroup_convert_reserved_meta(root, qgroup_reserved); return h; join_fail: if (type & __TRANS_FREEZABLE) sb_end_intwrite(fs_info->sb); kmem_cache_free(btrfs_trans_handle_cachep, h); alloc_fail: if (num_bytes) btrfs_block_rsv_release(fs_info, trans_rsv, num_bytes, NULL); if (delayed_refs_bytes) btrfs_space_info_free_bytes_may_use(fs_info, trans_rsv->space_info, delayed_refs_bytes); reserve_fail: btrfs_qgroup_free_meta_prealloc(root, qgroup_reserved); return ERR_PTR(ret); } struct btrfs_trans_handle *btrfs_start_transaction(struct btrfs_root *root, unsigned int num_items) { return start_transaction(root, num_items, TRANS_START, BTRFS_RESERVE_FLUSH_ALL, true); } struct btrfs_trans_handle *btrfs_start_transaction_fallback_global_rsv( struct btrfs_root *root, unsigned int num_items) { return start_transaction(root, num_items, TRANS_START, BTRFS_RESERVE_FLUSH_ALL_STEAL, false); } struct btrfs_trans_handle *btrfs_join_transaction(struct btrfs_root *root) { return start_transaction(root, 0, TRANS_JOIN, BTRFS_RESERVE_NO_FLUSH, true); } struct btrfs_trans_handle *btrfs_join_transaction_spacecache(struct btrfs_root *root) { return start_transaction(root, 0, TRANS_JOIN_NOLOCK, BTRFS_RESERVE_NO_FLUSH, true); } /* * Similar to regular join but it never starts a transaction when none is * running or when there's a running one at a state >= TRANS_STATE_UNBLOCKED. * This is similar to btrfs_attach_transaction() but it allows the join to * happen if the transaction commit already started but it's not yet in the * "doing" phase (the state is < TRANS_STATE_COMMIT_DOING). */ struct btrfs_trans_handle *btrfs_join_transaction_nostart(struct btrfs_root *root) { return start_transaction(root, 0, TRANS_JOIN_NOSTART, BTRFS_RESERVE_NO_FLUSH, true); } /* * 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, BTRFS_RESERVE_NO_FLUSH, true); } /* * Catch the running transaction. * * It is similar to the above function, the difference 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, BTRFS_RESERVE_NO_FLUSH, true); if (trans == ERR_PTR(-ENOENT)) { int ret; ret = btrfs_wait_for_commit(root->fs_info, 0); if (ret) return ERR_PTR(ret); } return trans; } /* Wait for a transaction commit to reach at least the given state. */ static noinline void wait_for_commit(struct btrfs_transaction *commit, const enum btrfs_trans_state min_state) { struct btrfs_fs_info *fs_info = commit->fs_info; u64 transid = commit->transid; bool put = false; /* * At the moment this function is called with min_state either being * TRANS_STATE_COMPLETED or TRANS_STATE_SUPER_COMMITTED. */ if (min_state == TRANS_STATE_COMPLETED) btrfs_might_wait_for_state(fs_info, BTRFS_LOCKDEP_TRANS_COMPLETED); else btrfs_might_wait_for_state(fs_info, BTRFS_LOCKDEP_TRANS_SUPER_COMMITTED); while (1) { wait_event(commit->commit_wait, commit->state >= min_state); if (put) btrfs_put_transaction(commit); if (min_state < TRANS_STATE_COMPLETED) break; /* * A transaction isn't really completed until all of the * previous transactions are completed, but with fsync we can * end up with SUPER_COMMITTED transactions before a COMPLETED * transaction. Wait for those. */ spin_lock(&fs_info->trans_lock); commit = list_first_entry_or_null(&fs_info->trans_list, struct btrfs_transaction, list); if (!commit || commit->transid > transid) { spin_unlock(&fs_info->trans_lock); break; } refcount_inc(&commit->use_count); put = true; spin_unlock(&fs_info->trans_lock); } } int btrfs_wait_for_commit(struct btrfs_fs_info *fs_info, u64 transid) { struct btrfs_transaction *cur_trans = NULL, *t; int ret = 0; if (transid) { if (transid <= btrfs_get_last_trans_committed(fs_info)) goto out; /* find specified transaction */ spin_lock(&fs_info->trans_lock); list_for_each_entry(t, &fs_info->trans_list, list) { if (t->transid == transid) { cur_trans = t; refcount_inc(&cur_trans->use_count); ret = 0; break; } if (t->transid > transid) { ret = 0; break; } } spin_unlock(&fs_info->trans_lock); /* * The specified transaction doesn't exist, or we * raced with btrfs_commit_transaction */ if (!cur_trans) { if (transid > btrfs_get_last_trans_committed(fs_info)) ret = -EINVAL; goto out; } } else { /* find newest transaction that is committing | committed */ spin_lock(&fs_info->trans_lock); list_for_each_entry_reverse(t, &fs_info->trans_list, list) { if (t->state >= TRANS_STATE_COMMIT_START) { if (t->state == TRANS_STATE_COMPLETED) break; cur_trans = t; refcount_inc(&cur_trans->use_count); break; } } spin_unlock(&fs_info->trans_lock); if (!cur_trans) goto out; /* nothing committing|committed */ } wait_for_commit(cur_trans, TRANS_STATE_COMPLETED); ret = cur_trans->aborted; btrfs_put_transaction(cur_trans); out: return ret; } void btrfs_throttle(struct btrfs_fs_info *fs_info) { wait_current_trans(fs_info); } bool btrfs_should_end_transaction(struct btrfs_trans_handle *trans) { struct btrfs_transaction *cur_trans = trans->transaction; if (cur_trans->state >= TRANS_STATE_COMMIT_START || test_bit(BTRFS_DELAYED_REFS_FLUSHING, &cur_trans->delayed_refs.flags)) return true; if (btrfs_check_space_for_delayed_refs(trans->fs_info)) return true; return !!btrfs_block_rsv_check(&trans->fs_info->global_block_rsv, 50); } static void btrfs_trans_release_metadata(struct btrfs_trans_handle *trans) { struct btrfs_fs_info *fs_info = trans->fs_info; if (!trans->block_rsv) { ASSERT(!trans->bytes_reserved); ASSERT(!trans->delayed_refs_bytes_reserved); return; } if (!trans->bytes_reserved) { ASSERT(!trans->delayed_refs_bytes_reserved); return; } ASSERT(trans->block_rsv == &fs_info->trans_block_rsv); trace_btrfs_space_reservation(fs_info, "transaction", trans->transid, trans->bytes_reserved, 0); btrfs_block_rsv_release(fs_info, trans->block_rsv, trans->bytes_reserved, NULL); trans->bytes_reserved = 0; if (!trans->delayed_refs_bytes_reserved) return; trace_btrfs_space_reservation(fs_info, "local_delayed_refs_rsv", trans->transid, trans->delayed_refs_bytes_reserved, 0); btrfs_block_rsv_release(fs_info, &trans->delayed_rsv, trans->delayed_refs_bytes_reserved, NULL); trans->delayed_refs_bytes_reserved = 0; } static int __btrfs_end_transaction(struct btrfs_trans_handle *trans, int throttle) { struct btrfs_fs_info *info = trans->fs_info; struct btrfs_transaction *cur_trans = trans->transaction; int ret = 0; if (refcount_read(&trans->use_count) > 1) { refcount_dec(&trans->use_count); trans->block_rsv = trans->orig_rsv; return 0; } btrfs_trans_release_metadata(trans); trans->block_rsv = NULL; btrfs_create_pending_block_groups(trans); btrfs_trans_release_chunk_metadata(trans); if (trans->type & __TRANS_FREEZABLE) sb_end_intwrite(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); cond_wake_up(&cur_trans->writer_wait); btrfs_lockdep_release(info, btrfs_trans_num_extwriters); btrfs_lockdep_release(info, btrfs_trans_num_writers); btrfs_put_transaction(cur_trans); if (current->journal_info == trans) current->journal_info = NULL; if (throttle) btrfs_run_delayed_iputs(info); if (TRANS_ABORTED(trans) || BTRFS_FS_ERROR(info)) { wake_up_process(info->transaction_kthread); if (TRANS_ABORTED(trans)) ret = trans->aborted; else ret = -EROFS; } kmem_cache_free(btrfs_trans_handle_cachep, trans); return ret; } int btrfs_end_transaction(struct btrfs_trans_handle *trans) { return __btrfs_end_transaction(trans, 0); } int btrfs_end_transaction_throttle(struct btrfs_trans_handle *trans) { return __btrfs_end_transaction(trans, 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_fs_info *fs_info, struct extent_io_tree *dirty_pages, int mark) { int ret = 0; struct address_space *mapping = 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)) { bool wait_writeback = false; ret = convert_extent_bit(dirty_pages, start, end, EXTENT_NEED_WAIT, mark, &cached_state); /* * convert_extent_bit can return -ENOMEM, which is most of the * time a temporary error. So when it happens, ignore the error * and wait for writeback of this range to finish - because we * failed to set the bit EXTENT_NEED_WAIT for the range, a call * to __btrfs_wait_marked_extents() would not know that * writeback for this range started and therefore wouldn't * wait for it to finish - we don't want to commit a * superblock that points to btree nodes/leafs for which * writeback hasn't finished yet (and without errors). * We cleanup any entries left in the io tree when committing * the transaction (through extent_io_tree_release()). */ if (ret == -ENOMEM) { ret = 0; wait_writeback = true; } if (!ret) ret = filemap_fdatawrite_range(mapping, start, end); if (!ret && wait_writeback) ret = filemap_fdatawait_range(mapping, start, end); free_extent_state(cached_state); if (ret) break; cached_state = NULL; cond_resched(); start = end + 1; } return ret; } /* * 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 */ static int __btrfs_wait_marked_extents(struct btrfs_fs_info *fs_info, struct extent_io_tree *dirty_pages) { struct address_space *mapping = fs_info->btree_inode->i_mapping; struct extent_state *cached_state = NULL; u64 start = 0; u64 end; int ret = 0; while (find_first_extent_bit(dirty_pages, start, &start, &end, EXTENT_NEED_WAIT, &cached_state)) { /* * Ignore -ENOMEM errors returned by clear_extent_bit(). * When committing the transaction, we'll remove any entries * left in the io tree. For a log commit, we don't remove them * after committing the log because the tree can be accessed * concurrently - we do it only at transaction commit time when * it's safe to do it (through extent_io_tree_release()). */ ret = clear_extent_bit(dirty_pages, start, end, EXTENT_NEED_WAIT, &cached_state); if (ret == -ENOMEM) ret = 0; if (!ret) ret = filemap_fdatawait_range(mapping, start, end); free_extent_state(cached_state); if (ret) break; cached_state = NULL; cond_resched(); start = end + 1; } return ret; } static int btrfs_wait_extents(struct btrfs_fs_info *fs_info, struct extent_io_tree *dirty_pages) { bool errors = false; int err; err = __btrfs_wait_marked_extents(fs_info, dirty_pages); if (test_and_clear_bit(BTRFS_FS_BTREE_ERR, &fs_info->flags)) errors = true; if (errors && !err) err = -EIO; return err; } int btrfs_wait_tree_log_extents(struct btrfs_root *log_root, int mark) { struct btrfs_fs_info *fs_info = log_root->fs_info; struct extent_io_tree *dirty_pages = &log_root->dirty_log_pages; bool errors = false; int err; ASSERT(btrfs_root_id(log_root) == BTRFS_TREE_LOG_OBJECTID); err = __btrfs_wait_marked_extents(fs_info, dirty_pages); if ((mark & EXTENT_DIRTY) && test_and_clear_bit(BTRFS_FS_LOG1_ERR, &fs_info->flags)) errors = true; if ((mark & EXTENT_NEW) && test_and_clear_bit(BTRFS_FS_LOG2_ERR, &fs_info->flags)) errors = true; if (errors && !err) err = -EIO; return err; } /* * When btree blocks are allocated the corresponding extents are marked dirty. * This function ensures such extents are persisted on disk for transaction or * log commit. * * @trans: transaction whose dirty pages we'd like to write */ static int btrfs_write_and_wait_transaction(struct btrfs_trans_handle *trans) { int ret; int ret2; struct extent_io_tree *dirty_pages = &trans->transaction->dirty_pages; struct btrfs_fs_info *fs_info = trans->fs_info; struct blk_plug plug; blk_start_plug(&plug); ret = btrfs_write_marked_extents(fs_info, dirty_pages, EXTENT_DIRTY); blk_finish_plug(&plug); ret2 = btrfs_wait_extents(fs_info, dirty_pages); extent_io_tree_release(&trans->transaction->dirty_pages); if (ret) return ret; else if (ret2) return ret2; else return 0; } /* * 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_fs_info *fs_info = root->fs_info; struct btrfs_root *tree_root = fs_info->tree_root; old_root_used = btrfs_root_used(&root->root_item); 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); } 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_fs_info *fs_info = trans->fs_info; struct list_head *dirty_bgs = &trans->transaction->dirty_bgs; struct list_head *io_bgs = &trans->transaction->io_bgs; struct list_head *next; struct extent_buffer *eb; int ret; /* * At this point no one can be using this transaction to modify any tree * and no one can start another transaction to modify any tree either. */ ASSERT(trans->transaction->state == TRANS_STATE_COMMIT_DOING); eb = btrfs_lock_root_node(fs_info->tree_root); ret = btrfs_cow_block(trans, fs_info->tree_root, eb, NULL, 0, &eb, BTRFS_NESTING_COW); btrfs_tree_unlock(eb); free_extent_buffer(eb); if (ret) return ret; ret = btrfs_run_dev_stats(trans); if (ret) return ret; ret = btrfs_run_dev_replace(trans); if (ret) return ret; ret = btrfs_run_qgroups(trans); if (ret) return ret; ret = btrfs_setup_space_cache(trans); if (ret) return ret; again: while (!list_empty(&fs_info->dirty_cowonly_roots)) { struct btrfs_root *root; next = fs_info->dirty_cowonly_roots.next; list_del_init(next); root = list_entry(next, struct btrfs_root, dirty_list); clear_bit(BTRFS_ROOT_DIRTY, &root->state); list_add_tail(&root->dirty_list, &trans->transaction->switch_commits); ret = update_cowonly_root(trans, root); if (ret) return ret; } /* Now flush any delayed refs generated by updating all of the roots */ ret = btrfs_run_delayed_refs(trans, U64_MAX); if (ret) return ret; while (!list_empty(dirty_bgs) || !list_empty(io_bgs)) { ret = btrfs_write_dirty_block_groups(trans); if (ret) return ret; /* * We're writing the dirty block groups, which could generate * delayed refs, which could generate more dirty block groups, * so we want to keep this flushing in this loop to make sure * everything gets run. */ ret = btrfs_run_delayed_refs(trans, U64_MAX); if (ret) return ret; } if (!list_empty(&fs_info->dirty_cowonly_roots)) goto again; /* Update dev-replace pointer once everything is committed */ fs_info->dev_replace.committed_cursor_left = fs_info->dev_replace.cursor_left_last_write_of_item; return 0; } /* * If we had a pending drop we need to see if there are any others left in our * dead roots list, and if not clear our bit and wake any waiters. */ void btrfs_maybe_wake_unfinished_drop(struct btrfs_fs_info *fs_info) { /* * We put the drop in progress roots at the front of the list, so if the * first entry doesn't have UNFINISHED_DROP set we can wake everybody * up. */ spin_lock(&fs_info->trans_lock); if (!list_empty(&fs_info->dead_roots)) { struct btrfs_root *root = list_first_entry(&fs_info->dead_roots, struct btrfs_root, root_list); if (test_bit(BTRFS_ROOT_UNFINISHED_DROP, &root->state)) { spin_unlock(&fs_info->trans_lock); return; } } spin_unlock(&fs_info->trans_lock); btrfs_wake_unfinished_drop(fs_info); } /* * 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) { struct btrfs_fs_info *fs_info = root->fs_info; spin_lock(&fs_info->trans_lock); if (list_empty(&root->root_list)) { btrfs_grab_root(root); /* We want to process the partially complete drops first. */ if (test_bit(BTRFS_ROOT_UNFINISHED_DROP, &root->state)) list_add(&root->root_list, &fs_info->dead_roots); else list_add_tail(&root->root_list, &fs_info->dead_roots); } spin_unlock(&fs_info->trans_lock); } /* * Update each subvolume root and its relocation root, if it exists, in the tree * of tree roots. Also free log roots if they exist. */ static noinline int commit_fs_roots(struct btrfs_trans_handle *trans) { struct btrfs_fs_info *fs_info = trans->fs_info; struct btrfs_root *gang[8]; int i; int ret; /* * At this point no one can be using this transaction to modify any tree * and no one can start another transaction to modify any tree either. */ ASSERT(trans->transaction->state == TRANS_STATE_COMMIT_DOING); 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++) { struct btrfs_root *root = gang[i]; int ret2; /* * At this point we can neither have tasks logging inodes * from a root nor trying to commit a log tree. */ ASSERT(atomic_read(&root->log_writers) == 0); ASSERT(atomic_read(&root->log_commit[0]) == 0); ASSERT(atomic_read(&root->log_commit[1]) == 0); radix_tree_tag_clear(&fs_info->fs_roots_radix, (unsigned long)btrfs_root_id(root), BTRFS_ROOT_TRANS_TAG); btrfs_qgroup_free_meta_all_pertrans(root); spin_unlock(&fs_info->fs_roots_radix_lock); btrfs_free_log(trans, root); ret2 = btrfs_update_reloc_root(trans, root); if (ret2) return ret2; /* 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); } ret2 = btrfs_update_root(trans, fs_info->tree_root, &root->root_key, &root->root_item); if (ret2) return ret2; spin_lock(&fs_info->fs_roots_radix_lock); } } spin_unlock(&fs_info->fs_roots_radix_lock); return 0; } /* * Do all special snapshot related qgroup dirty hack. * * Will do all needed qgroup inherit and dirty hack like switch commit * roots inside one transaction and write all btree into disk, to make * qgroup works. */ static int qgroup_account_snapshot(struct btrfs_trans_handle *trans, struct btrfs_root *src, struct btrfs_root *parent, struct btrfs_qgroup_inherit *inherit, u64 dst_objectid) { struct btrfs_fs_info *fs_info = src->fs_info; int ret; /* * Save some performance in the case that qgroups are not enabled. If * this check races with the ioctl, rescan will kick in anyway. */ if (!btrfs_qgroup_full_accounting(fs_info)) return 0; /* * Ensure dirty @src will be committed. Or, after coming * commit_fs_roots() and switch_commit_roots(), any dirty but not * recorded root will never be updated again, causing an outdated root * item. */ ret = record_root_in_trans(trans, src, 1); if (ret) return ret; /* * btrfs_qgroup_inherit relies on a consistent view of the usage for the * src root, so we must run the delayed refs here. * * However this isn't particularly fool proof, because there's no * synchronization keeping us from changing the tree after this point * before we do the qgroup_inherit, or even from making changes while * we're doing the qgroup_inherit. But that's a problem for the future, * for now flush the delayed refs to narrow the race window where the * qgroup counters could end up wrong. */ ret = btrfs_run_delayed_refs(trans, U64_MAX); if (ret) { btrfs_abort_transaction(trans, ret); return ret; } ret = commit_fs_roots(trans); if (ret) goto out; ret = btrfs_qgroup_account_extents(trans); if (ret < 0) goto out; /* Now qgroup are all updated, we can inherit it to new qgroups */ ret = btrfs_qgroup_inherit(trans, btrfs_root_id(src), dst_objectid, btrfs_root_id(parent), inherit); if (ret < 0) goto out; /* * Now we do a simplified commit transaction, which will: * 1) commit all subvolume and extent tree * To ensure all subvolume and extent tree have a valid * commit_root to accounting later insert_dir_item() * 2) write all btree blocks onto disk * This is to make sure later btree modification will be cowed * Or commit_root can be populated and cause wrong qgroup numbers * In this simplified commit, we don't really care about other trees * like chunk and root tree, as they won't affect qgroup. * And we don't write super to avoid half committed status. */ ret = commit_cowonly_roots(trans); if (ret) goto out; switch_commit_roots(trans); ret = btrfs_write_and_wait_transaction(trans); if (ret) btrfs_handle_fs_error(fs_info, ret, "Error while writing out transaction for qgroup"); out: /* * Force parent root to be updated, as we recorded it before so its * last_trans == cur_transid. * Or it won't be committed again onto disk after later * insert_dir_item() */ if (!ret) ret = record_root_in_trans(trans, parent, 1); 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_pending_snapshot *pending) { struct btrfs_fs_info *fs_info = trans->fs_info; 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 = &pending->dir->vfs_inode; struct btrfs_path *path; struct btrfs_dir_item *dir_item; struct extent_buffer *tmp; struct extent_buffer *old; struct timespec64 cur_time; int ret = 0; u64 to_reserve = 0; u64 index = 0; u64 objectid; u64 root_flags; unsigned int nofs_flags; struct fscrypt_name fname; ASSERT(pending->path); path = pending->path; ASSERT(pending->root_item); new_root_item = pending->root_item; /* * We're inside a transaction and must make sure that any potential * allocations with GFP_KERNEL in fscrypt won't recurse back to * filesystem. */ nofs_flags = memalloc_nofs_save(); pending->error = fscrypt_setup_filename(parent_inode, &pending->dentry->d_name, 0, &fname); memalloc_nofs_restore(nofs_flags); if (pending->error) goto free_pending; pending->error = btrfs_get_free_objectid(tree_root, &objectid); if (pending->error) goto free_fname; /* * Make qgroup to skip current new snapshot's qgroupid, as it is * accounted by later btrfs_qgroup_inherit(). */ btrfs_set_skip_qgroup(trans, objectid); btrfs_reloc_pre_snapshot(pending, &to_reserve); if (to_reserve > 0) { pending->error = btrfs_block_rsv_add(fs_info, &pending->block_rsv, to_reserve, BTRFS_RESERVE_NO_FLUSH); if (pending->error) goto clear_skip_qgroup; } 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; trace_btrfs_space_reservation(fs_info, "transaction", trans->transid, trans->bytes_reserved, 1); parent_root = BTRFS_I(parent_inode)->root; ret = record_root_in_trans(trans, parent_root, 0); if (ret) goto fail; cur_time = current_time(parent_inode); /* * insert the directory item */ ret = btrfs_set_inode_index(BTRFS_I(parent_inode), &index); if (ret) { btrfs_abort_transaction(trans, ret); goto fail; } /* check if there is a file/dir which has the same name. */ dir_item = btrfs_lookup_dir_item(NULL, parent_root, path, btrfs_ino(BTRFS_I(parent_inode)), &fname.disk_name, 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, ret); goto fail; } btrfs_release_path(path); ret = btrfs_create_qgroup(trans, objectid); if (ret && ret != -EEXIST) { btrfs_abort_transaction(trans, ret); goto fail; } /* * pull in the delayed directory update * and the delayed inode item * otherwise we corrupt the FS during * snapshot */ ret = btrfs_run_delayed_items(trans); if (ret) { /* Transaction aborted */ btrfs_abort_transaction(trans, ret); goto fail; } ret = record_root_in_trans(trans, root, 0); if (ret) { btrfs_abort_transaction(trans, ret); goto fail; } 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); generate_random_guid(new_root_item->uuid); 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, BTRFS_NESTING_COW); if (ret) { btrfs_tree_unlock(old); free_extent_buffer(old); btrfs_abort_transaction(trans, ret); goto fail; } 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, 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, ret); goto fail; } /* * insert root back/forward references */ ret = btrfs_add_root_ref(trans, objectid, btrfs_root_id(parent_root), btrfs_ino(BTRFS_I(parent_inode)), index, &fname.disk_name); if (ret) { btrfs_abort_transaction(trans, ret); goto fail; } key.offset = (u64)-1; pending->snap = btrfs_get_new_fs_root(fs_info, objectid, &pending->anon_dev); if (IS_ERR(pending->snap)) { ret = PTR_ERR(pending->snap); pending->snap = NULL; btrfs_abort_transaction(trans, ret); goto fail; } ret = btrfs_reloc_post_snapshot(trans, pending); if (ret) { btrfs_abort_transaction(trans, ret); goto fail; } /* * Do special qgroup accounting for snapshot, as we do some qgroup * snapshot hack to do fast snapshot. * To co-operate with that hack, we do hack again. * Or snapshot will be greatly slowed down by a subtree qgroup rescan */ if (btrfs_qgroup_mode(fs_info) == BTRFS_QGROUP_MODE_FULL) ret = qgroup_account_snapshot(trans, root, parent_root, pending->inherit, objectid); else if (btrfs_qgroup_mode(fs_info) == BTRFS_QGROUP_MODE_SIMPLE) ret = btrfs_qgroup_inherit(trans, btrfs_root_id(root), objectid, btrfs_root_id(parent_root), pending->inherit); if (ret < 0) goto fail; ret = btrfs_insert_dir_item(trans, &fname.disk_name, BTRFS_I(parent_inode), &key, BTRFS_FT_DIR, index); if (ret) { btrfs_abort_transaction(trans, ret); goto fail; } btrfs_i_size_write(BTRFS_I(parent_inode), parent_inode->i_size + fname.disk_name.len * 2); inode_set_mtime_to_ts(parent_inode, inode_set_ctime_current(parent_inode)); ret = btrfs_update_inode_fallback(trans, BTRFS_I(parent_inode)); if (ret) { btrfs_abort_transaction(trans, ret); goto fail; } ret = btrfs_uuid_tree_add(trans, new_root_item->uuid, BTRFS_UUID_KEY_SUBVOL, objectid); if (ret) { btrfs_abort_transaction(trans, ret); goto fail; } if (!btrfs_is_empty_uuid(new_root_item->received_uuid)) { ret = btrfs_uuid_tree_add(trans, new_root_item->received_uuid, BTRFS_UUID_KEY_RECEIVED_SUBVOL, objectid); if (ret && ret != -EEXIST) { btrfs_abort_transaction(trans, ret); goto fail; } } fail: pending->error = ret; dir_item_existed: trans->block_rsv = rsv; trans->bytes_reserved = 0; clear_skip_qgroup: btrfs_clear_skip_qgroup(trans); free_fname: fscrypt_free_filename(&fname); free_pending: kfree(new_root_item); pending->root_item = NULL; btrfs_free_path(path); pending->path = NULL; return ret; } /* * create all the snapshots we've scheduled for creation */ static noinline int create_pending_snapshots(struct btrfs_trans_handle *trans) { 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, pending); if (ret) break; } return ret; } static void update_super_roots(struct btrfs_fs_info *fs_info) { struct btrfs_root_item *root_item; struct btrfs_super_block *super; super = fs_info->super_copy; root_item = &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 = &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(fs_info, SPACE_CACHE)) super->cache_generation = root_item->generation; else if (test_bit(BTRFS_FS_CLEANUP_SPACE_CACHE_V1, &fs_info->flags)) super->cache_generation = 0; if (test_bit(BTRFS_FS_UPDATE_UUID_TREE_GEN, &fs_info->flags)) super->uuid_tree_generation = root_item->generation; } 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; } void btrfs_commit_transaction_async(struct btrfs_trans_handle *trans) { struct btrfs_fs_info *fs_info = trans->fs_info; struct btrfs_transaction *cur_trans; /* Kick the transaction kthread. */ set_bit(BTRFS_FS_COMMIT_TRANS, &fs_info->flags); wake_up_process(fs_info->transaction_kthread); /* take transaction reference */ cur_trans = trans->transaction; refcount_inc(&cur_trans->use_count); btrfs_end_transaction(trans); /* * Wait for the current transaction commit to start and block * subsequent transaction joins */ btrfs_might_wait_for_state(fs_info, BTRFS_LOCKDEP_TRANS_COMMIT_PREP); wait_event(fs_info->transaction_blocked_wait, cur_trans->state >= TRANS_STATE_COMMIT_START || TRANS_ABORTED(cur_trans)); btrfs_put_transaction(cur_trans); } /* * If there is a running transaction commit it or if it's already committing, * wait for its commit to complete. Does not start and commit a new transaction * if there isn't any running. */ int btrfs_commit_current_transaction(struct btrfs_root *root) { struct btrfs_trans_handle *trans; trans = btrfs_attach_transaction_barrier(root); if (IS_ERR(trans)) { int ret = PTR_ERR(trans); return (ret == -ENOENT) ? 0 : ret; } return btrfs_commit_transaction(trans); } static void cleanup_transaction(struct btrfs_trans_handle *trans, int err) { struct btrfs_fs_info *fs_info = trans->fs_info; struct btrfs_transaction *cur_trans = trans->transaction; WARN_ON(refcount_read(&trans->use_count) > 1); btrfs_abort_transaction(trans, err); spin_lock(&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)); if (cur_trans == fs_info->running_transaction) { cur_trans->state = TRANS_STATE_COMMIT_DOING; spin_unlock(&fs_info->trans_lock); /* * The thread has already released the lockdep map as reader * already in btrfs_commit_transaction(). */ btrfs_might_wait_for_event(fs_info, btrfs_trans_num_writers); wait_event(cur_trans->writer_wait, atomic_read(&cur_trans->num_writers) == 1); spin_lock(&fs_info->trans_lock); } /* * Now that we know no one else is still using the transaction we can * remove the transaction from the list of transactions. This avoids * the transaction kthread from cleaning up the transaction while some * other task is still using it, which could result in a use-after-free * on things like log trees, as it forces the transaction kthread to * wait for this transaction to be cleaned up by us. */ list_del_init(&cur_trans->list); spin_unlock(&fs_info->trans_lock); btrfs_cleanup_one_transaction(trans->transaction); spin_lock(&fs_info->trans_lock); if (cur_trans == fs_info->running_transaction) fs_info->running_transaction = NULL; spin_unlock(&fs_info->trans_lock); if (trans->type & __TRANS_FREEZABLE) sb_end_intwrite(fs_info->sb); btrfs_put_transaction(cur_trans); btrfs_put_transaction(cur_trans); trace_btrfs_transaction_commit(fs_info); if (current->journal_info == trans) current->journal_info = NULL; /* * If relocation is running, we can't cancel scrub because that will * result in a deadlock. Before relocating a block group, relocation * pauses scrub, then starts and commits a transaction before unpausing * scrub. If the transaction commit is being done by the relocation * task or triggered by another task and the relocation task is waiting * for the commit, and we end up here due to an error in the commit * path, then calling btrfs_scrub_cancel() will deadlock, as we are * asking for scrub to stop while having it asked to be paused higher * above in relocation code. */ if (!test_bit(BTRFS_FS_RELOC_RUNNING, &fs_info->flags)) btrfs_scrub_cancel(fs_info); kmem_cache_free(btrfs_trans_handle_cachep, trans); } /* * Release reserved delayed ref space of all pending block groups of the * transaction and remove them from the list */ static void btrfs_cleanup_pending_block_groups(struct btrfs_trans_handle *trans) { struct btrfs_fs_info *fs_info = trans->fs_info; struct btrfs_block_group *block_group, *tmp; list_for_each_entry_safe(block_group, tmp, &trans->new_bgs, bg_list) { btrfs_dec_delayed_refs_rsv_bg_inserts(fs_info); list_del_init(&block_group->bg_list); } } static inline int btrfs_start_delalloc_flush(struct btrfs_fs_info *fs_info) { /* * We use try_to_writeback_inodes_sb() here because if we used * btrfs_start_delalloc_roots we would deadlock with fs freeze. * Currently are holding the fs freeze lock, if we do an async flush * we'll do btrfs_join_transaction() and deadlock because we need to * wait for the fs freeze lock. Using the direct flushing we benefit * from already being in a transaction and our join_transaction doesn't * have to re-take the fs freeze lock. * * Note that try_to_writeback_inodes_sb() will only trigger writeback * if it can read lock sb->s_umount. It will always be able to lock it, * except when the filesystem is being unmounted or being frozen, but in * those cases sync_filesystem() is called, which results in calling * writeback_inodes_sb() while holding a write lock on sb->s_umount. * Note that we don't call writeback_inodes_sb() directly, because it * will emit a warning if sb->s_umount is not locked. */ if (btrfs_test_opt(fs_info, FLUSHONCOMMIT)) try_to_writeback_inodes_sb(fs_info->sb, WB_REASON_SYNC); return 0; } static inline void btrfs_wait_delalloc_flush(struct btrfs_fs_info *fs_info) { if (btrfs_test_opt(fs_info, FLUSHONCOMMIT)) btrfs_wait_ordered_roots(fs_info, U64_MAX, NULL); } /* * Add a pending snapshot associated with the given transaction handle to the * respective handle. This must be called after the transaction commit started * and while holding fs_info->trans_lock. * This serves to guarantee a caller of btrfs_commit_transaction() that it can * safely free the pending snapshot pointer in case btrfs_commit_transaction() * returns an error. */ static void add_pending_snapshot(struct btrfs_trans_handle *trans) { struct btrfs_transaction *cur_trans = trans->transaction; if (!trans->pending_snapshot) return; lockdep_assert_held(&trans->fs_info->trans_lock); ASSERT(cur_trans->state >= TRANS_STATE_COMMIT_PREP); list_add(&trans->pending_snapshot->list, &cur_trans->pending_snapshots); } static void update_commit_stats(struct btrfs_fs_info *fs_info, ktime_t interval) { fs_info->commit_stats.commit_count++; fs_info->commit_stats.last_commit_dur = interval; fs_info->commit_stats.max_commit_dur = max_t(u64, fs_info->commit_stats.max_commit_dur, interval); fs_info->commit_stats.total_commit_dur += interval; } int btrfs_commit_transaction(struct btrfs_trans_handle *trans) { struct btrfs_fs_info *fs_info = trans->fs_info; struct btrfs_transaction *cur_trans = trans->transaction; struct btrfs_transaction *prev_trans = NULL; int ret; ktime_t start_time; ktime_t interval; ASSERT(refcount_read(&trans->use_count) == 1); btrfs_trans_state_lockdep_acquire(fs_info, BTRFS_LOCKDEP_TRANS_COMMIT_PREP); clear_bit(BTRFS_FS_NEED_TRANS_COMMIT, &fs_info->flags); /* Stop the commit early if ->aborted is set */ if (TRANS_ABORTED(cur_trans)) { ret = cur_trans->aborted; goto lockdep_trans_commit_start_release; } btrfs_trans_release_metadata(trans); trans->block_rsv = NULL; /* * We only want one transaction commit doing the flushing so we do not * waste a bunch of time on lock contention on the extent root node. */ if (!test_and_set_bit(BTRFS_DELAYED_REFS_FLUSHING, &cur_trans->delayed_refs.flags)) { /* * Make a pass through all the delayed refs we have so far. * Any running threads may add more while we are here. */ ret = btrfs_run_delayed_refs(trans, 0); if (ret) goto lockdep_trans_commit_start_release; } btrfs_create_pending_block_groups(trans); if (!test_bit(BTRFS_TRANS_DIRTY_BG_RUN, &cur_trans->flags)) { int run_it = 0; /* this mutex is also taken before trying to set * block groups readonly. We need to make sure * that nobody has set a block group readonly * after a extents from that block group have been * allocated for cache files. btrfs_set_block_group_ro * will wait for the transaction to commit if it * finds BTRFS_TRANS_DIRTY_BG_RUN set. * * The BTRFS_TRANS_DIRTY_BG_RUN flag is also used to make sure * only one process starts all the block group IO. It wouldn't * hurt to have more than one go through, but there's no * real advantage to it either. */ mutex_lock(&fs_info->ro_block_group_mutex); if (!test_and_set_bit(BTRFS_TRANS_DIRTY_BG_RUN, &cur_trans->flags)) run_it = 1; mutex_unlock(&fs_info->ro_block_group_mutex); if (run_it) { ret = btrfs_start_dirty_block_groups(trans); if (ret) goto lockdep_trans_commit_start_release; } } spin_lock(&fs_info->trans_lock); if (cur_trans->state >= TRANS_STATE_COMMIT_PREP) { enum btrfs_trans_state want_state = TRANS_STATE_COMPLETED; add_pending_snapshot(trans); spin_unlock(&fs_info->trans_lock); refcount_inc(&cur_trans->use_count); if (trans->in_fsync) want_state = TRANS_STATE_SUPER_COMMITTED; btrfs_trans_state_lockdep_release(fs_info, BTRFS_LOCKDEP_TRANS_COMMIT_PREP); ret = btrfs_end_transaction(trans); wait_for_commit(cur_trans, want_state); if (TRANS_ABORTED(cur_trans)) ret = cur_trans->aborted; btrfs_put_transaction(cur_trans); return ret; } cur_trans->state = TRANS_STATE_COMMIT_PREP; wake_up(&fs_info->transaction_blocked_wait); btrfs_trans_state_lockdep_release(fs_info, BTRFS_LOCKDEP_TRANS_COMMIT_PREP); if (cur_trans->list.prev != &fs_info->trans_list) { enum btrfs_trans_state want_state = TRANS_STATE_COMPLETED; if (trans->in_fsync) want_state = TRANS_STATE_SUPER_COMMITTED; prev_trans = list_entry(cur_trans->list.prev, struct btrfs_transaction, list); if (prev_trans->state < want_state) { refcount_inc(&prev_trans->use_count); spin_unlock(&fs_info->trans_lock); wait_for_commit(prev_trans, want_state); ret = READ_ONCE(prev_trans->aborted); btrfs_put_transaction(prev_trans); if (ret) goto lockdep_release; spin_lock(&fs_info->trans_lock); } } else { /* * The previous transaction was aborted and was already removed * from the list of transactions at fs_info->trans_list. So we * abort to prevent writing a new superblock that reflects a * corrupt state (pointing to trees with unwritten nodes/leafs). */ if (BTRFS_FS_ERROR(fs_info)) { spin_unlock(&fs_info->trans_lock); ret = -EROFS; goto lockdep_release; } } cur_trans->state = TRANS_STATE_COMMIT_START; wake_up(&fs_info->transaction_blocked_wait); spin_unlock(&fs_info->trans_lock); /* * Get the time spent on the work done by the commit thread and not * the time spent waiting on a previous commit */ start_time = ktime_get_ns(); extwriter_counter_dec(cur_trans, trans->type); ret = btrfs_start_delalloc_flush(fs_info); if (ret) goto lockdep_release; ret = btrfs_run_delayed_items(trans); if (ret) goto lockdep_release; /* * The thread has started/joined the transaction thus it holds the * lockdep map as a reader. It has to release it before acquiring the * lockdep map as a writer. */ btrfs_lockdep_release(fs_info, btrfs_trans_num_extwriters); btrfs_might_wait_for_event(fs_info, btrfs_trans_num_extwriters); 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); if (ret) { btrfs_lockdep_release(fs_info, btrfs_trans_num_writers); goto cleanup_transaction; } btrfs_wait_delalloc_flush(fs_info); /* * Wait for all ordered extents started by a fast fsync that joined this * transaction. Otherwise if this transaction commits before the ordered * extents complete we lose logged data after a power failure. */ btrfs_might_wait_for_event(fs_info, btrfs_trans_pending_ordered); wait_event(cur_trans->pending_wait, atomic_read(&cur_trans->pending_ordered) == 0); btrfs_scrub_pause(fs_info); /* * 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(&fs_info->trans_lock); add_pending_snapshot(trans); cur_trans->state = TRANS_STATE_COMMIT_DOING; spin_unlock(&fs_info->trans_lock); /* * The thread has started/joined the transaction thus it holds the * lockdep map as a reader. It has to release it before acquiring the * lockdep map as a writer. */ btrfs_lockdep_release(fs_info, btrfs_trans_num_writers); btrfs_might_wait_for_event(fs_info, btrfs_trans_num_writers); wait_event(cur_trans->writer_wait, atomic_read(&cur_trans->num_writers) == 1); /* * Make lockdep happy by acquiring the state locks after * btrfs_trans_num_writers is released. If we acquired the state locks * before releasing the btrfs_trans_num_writers lock then lockdep would * complain because we did not follow the reverse order unlocking rule. */ btrfs_trans_state_lockdep_acquire(fs_info, BTRFS_LOCKDEP_TRANS_COMPLETED); btrfs_trans_state_lockdep_acquire(fs_info, BTRFS_LOCKDEP_TRANS_SUPER_COMMITTED); btrfs_trans_state_lockdep_acquire(fs_info, BTRFS_LOCKDEP_TRANS_UNBLOCKED); /* * We've started the commit, clear the flag in case we were triggered to * do an async commit but somebody else started before the transaction * kthread could do the work. */ clear_bit(BTRFS_FS_COMMIT_TRANS, &fs_info->flags); if (TRANS_ABORTED(cur_trans)) { ret = cur_trans->aborted; btrfs_trans_state_lockdep_release(fs_info, BTRFS_LOCKDEP_TRANS_UNBLOCKED); 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(&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); if (ret) goto unlock_reloc; /* * 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); if (ret) goto unlock_reloc; ret = btrfs_run_delayed_refs(trans, U64_MAX); if (ret) goto unlock_reloc; /* * make sure none of the code above managed to slip in a * delayed item */ btrfs_assert_delayed_root_empty(fs_info); WARN_ON(cur_trans != trans->transaction); ret = commit_fs_roots(trans); if (ret) goto unlock_reloc; /* 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, fs_info); /* * Since fs roots are all committed, we can get a quite accurate * new_roots. So let's do quota accounting. */ ret = btrfs_qgroup_account_extents(trans); if (ret < 0) goto unlock_reloc; ret = commit_cowonly_roots(trans); if (ret) goto unlock_reloc; /* * The tasks which save the space cache and inode cache may also * update ->aborted, check it. */ if (TRANS_ABORTED(cur_trans)) { ret = cur_trans->aborted; goto unlock_reloc; } cur_trans = fs_info->running_transaction; btrfs_set_root_node(&fs_info->tree_root->root_item, fs_info->tree_root->node); list_add_tail(&fs_info->tree_root->dirty_list, &cur_trans->switch_commits); btrfs_set_root_node(&fs_info->chunk_root->root_item, fs_info->chunk_root->node); list_add_tail(&fs_info->chunk_root->dirty_list, &cur_trans->switch_commits); if (btrfs_fs_incompat(fs_info, EXTENT_TREE_V2)) { btrfs_set_root_node(&fs_info->block_group_root->root_item, fs_info->block_group_root->node); list_add_tail(&fs_info->block_group_root->dirty_list, &cur_trans->switch_commits); } switch_commit_roots(trans); ASSERT(list_empty(&cur_trans->dirty_bgs)); ASSERT(list_empty(&cur_trans->io_bgs)); update_super_roots(fs_info); btrfs_set_super_log_root(fs_info->super_copy, 0); btrfs_set_super_log_root_level(fs_info->super_copy, 0); memcpy(fs_info->super_for_commit, fs_info->super_copy, sizeof(*fs_info->super_copy)); btrfs_commit_device_sizes(cur_trans); clear_bit(BTRFS_FS_LOG1_ERR, &fs_info->flags); clear_bit(BTRFS_FS_LOG2_ERR, &fs_info->flags); btrfs_trans_release_chunk_metadata(trans); /* * Before changing the transaction state to TRANS_STATE_UNBLOCKED and * setting fs_info->running_transaction to NULL, lock tree_log_mutex to * make sure that before we commit our superblock, no other task can * start a new transaction and commit a log tree before we commit our * superblock. Anyone trying to commit a log tree locks this mutex before * writing its superblock. */ mutex_lock(&fs_info->tree_log_mutex); spin_lock(&fs_info->trans_lock); cur_trans->state = TRANS_STATE_UNBLOCKED; fs_info->running_transaction = NULL; spin_unlock(&fs_info->trans_lock); mutex_unlock(&fs_info->reloc_mutex); wake_up(&fs_info->transaction_wait); btrfs_trans_state_lockdep_release(fs_info, BTRFS_LOCKDEP_TRANS_UNBLOCKED); /* If we have features changed, wake up the cleaner to update sysfs. */ if (test_bit(BTRFS_FS_FEATURE_CHANGED, &fs_info->flags) && fs_info->cleaner_kthread) wake_up_process(fs_info->cleaner_kthread); ret = btrfs_write_and_wait_transaction(trans); if (ret) { btrfs_handle_fs_error(fs_info, ret, "Error while writing out transaction"); mutex_unlock(&fs_info->tree_log_mutex); goto scrub_continue; } ret = write_all_supers(fs_info, 0); /* * the super is written, we can safely allow the tree-loggers * to go about their business */ mutex_unlock(&fs_info->tree_log_mutex); if (ret) goto scrub_continue; /* * We needn't acquire the lock here because there is no other task * which can change it. */ cur_trans->state = TRANS_STATE_SUPER_COMMITTED; wake_up(&cur_trans->commit_wait); btrfs_trans_state_lockdep_release(fs_info, BTRFS_LOCKDEP_TRANS_SUPER_COMMITTED); btrfs_finish_extent_commit(trans); if (test_bit(BTRFS_TRANS_HAVE_FREE_BGS, &cur_trans->flags)) btrfs_clear_space_info_full(fs_info); btrfs_set_last_trans_committed(fs_info, 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); btrfs_trans_state_lockdep_release(fs_info, BTRFS_LOCKDEP_TRANS_COMPLETED); spin_lock(&fs_info->trans_lock); list_del_init(&cur_trans->list); spin_unlock(&fs_info->trans_lock); btrfs_put_transaction(cur_trans); btrfs_put_transaction(cur_trans); if (trans->type & __TRANS_FREEZABLE) sb_end_intwrite(fs_info->sb); trace_btrfs_transaction_commit(fs_info); interval = ktime_get_ns() - start_time; btrfs_scrub_continue(fs_info); if (current->journal_info == trans) current->journal_info = NULL; kmem_cache_free(btrfs_trans_handle_cachep, trans); update_commit_stats(fs_info, interval); return ret; unlock_reloc: mutex_unlock(&fs_info->reloc_mutex); btrfs_trans_state_lockdep_release(fs_info, BTRFS_LOCKDEP_TRANS_UNBLOCKED); scrub_continue: btrfs_trans_state_lockdep_release(fs_info, BTRFS_LOCKDEP_TRANS_SUPER_COMMITTED); btrfs_trans_state_lockdep_release(fs_info, BTRFS_LOCKDEP_TRANS_COMPLETED); btrfs_scrub_continue(fs_info); cleanup_transaction: btrfs_trans_release_metadata(trans); btrfs_cleanup_pending_block_groups(trans); btrfs_trans_release_chunk_metadata(trans); trans->block_rsv = NULL; btrfs_warn(fs_info, "Skipping commit of aborted transaction."); if (current->journal_info == trans) current->journal_info = NULL; cleanup_transaction(trans, ret); return ret; lockdep_release: btrfs_lockdep_release(fs_info, btrfs_trans_num_extwriters); btrfs_lockdep_release(fs_info, btrfs_trans_num_writers); goto cleanup_transaction; lockdep_trans_commit_start_release: btrfs_trans_state_lockdep_release(fs_info, BTRFS_LOCKDEP_TRANS_COMMIT_PREP); btrfs_end_transaction(trans); 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_fs_info *fs_info) { struct btrfs_root *root; int ret; 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); btrfs_debug(fs_info, "cleaner removing %llu", btrfs_root_id(root)); btrfs_kill_all_delayed_nodes(root); if (btrfs_header_backref_rev(root->node) < BTRFS_MIXED_BACKREF_REV) ret = btrfs_drop_snapshot(root, 0, 0); else ret = btrfs_drop_snapshot(root, 1, 0); btrfs_put_root(root); return (ret < 0) ? 0 : 1; } /* * We only mark the transaction aborted and then set the file system read-only. * This will prevent new transactions from starting or trying to join this * one. * * This means that error recovery at the call site is limited to freeing * any local memory allocations and passing the error code up without * further cleanup. The transaction should complete as it normally would * in the call path but will return -EIO. * * We'll complete the cleanup in btrfs_end_transaction and * btrfs_commit_transaction. */ void __cold __btrfs_abort_transaction(struct btrfs_trans_handle *trans, const char *function, unsigned int line, int error, bool first_hit) { struct btrfs_fs_info *fs_info = trans->fs_info; WRITE_ONCE(trans->aborted, error); WRITE_ONCE(trans->transaction->aborted, error); if (first_hit && error == -ENOSPC) btrfs_dump_space_info_for_trans_abort(fs_info); /* Wake up anybody who may be waiting on this transaction */ wake_up(&fs_info->transaction_wait); wake_up(&fs_info->transaction_blocked_wait); __btrfs_handle_fs_error(fs_info, function, line, error, NULL); } int __init btrfs_transaction_init(void) { btrfs_trans_handle_cachep = KMEM_CACHE(btrfs_trans_handle, SLAB_TEMPORARY); if (!btrfs_trans_handle_cachep) return -ENOMEM; return 0; } void __cold btrfs_transaction_exit(void) { kmem_cache_destroy(btrfs_trans_handle_cachep); }