/* * 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/delay.h> #include <linux/kthread.h> #include <linux/pagemap.h> #include "ctree.h" #include "disk-io.h" #include "free-space-cache.h" #include "inode-map.h" #include "transaction.h" static int caching_kthread(void *data) { struct btrfs_root *root = data; struct btrfs_fs_info *fs_info = root->fs_info; struct btrfs_free_space_ctl *ctl = root->free_ino_ctl; struct btrfs_key key; struct btrfs_path *path; struct extent_buffer *leaf; u64 last = (u64)-1; int slot; int ret; if (!btrfs_test_opt(root, INODE_MAP_CACHE)) return 0; path = btrfs_alloc_path(); if (!path) return -ENOMEM; /* Since the commit root is read-only, we can safely skip locking. */ path->skip_locking = 1; path->search_commit_root = 1; path->reada = 2; key.objectid = BTRFS_FIRST_FREE_OBJECTID; key.offset = 0; key.type = BTRFS_INODE_ITEM_KEY; again: /* need to make sure the commit_root doesn't disappear */ mutex_lock(&root->fs_commit_mutex); ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); if (ret < 0) goto out; while (1) { if (btrfs_fs_closing(fs_info)) goto out; leaf = path->nodes[0]; slot = path->slots[0]; if (slot >= btrfs_header_nritems(leaf)) { ret = btrfs_next_leaf(root, path); if (ret < 0) goto out; else if (ret > 0) break; if (need_resched() || btrfs_transaction_in_commit(fs_info)) { leaf = path->nodes[0]; if (btrfs_header_nritems(leaf) == 0) { WARN_ON(1); break; } /* * Save the key so we can advances forward * in the next search. */ btrfs_item_key_to_cpu(leaf, &key, 0); btrfs_release_path(path); root->cache_progress = last; mutex_unlock(&root->fs_commit_mutex); schedule_timeout(1); goto again; } else continue; } btrfs_item_key_to_cpu(leaf, &key, slot); if (key.type != BTRFS_INODE_ITEM_KEY) goto next; if (key.objectid >= root->highest_objectid) break; if (last != (u64)-1 && last + 1 != key.objectid) { __btrfs_add_free_space(ctl, last + 1, key.objectid - last - 1); wake_up(&root->cache_wait); } last = key.objectid; next: path->slots[0]++; } if (last < root->highest_objectid - 1) { __btrfs_add_free_space(ctl, last + 1, root->highest_objectid - last - 1); } spin_lock(&root->cache_lock); root->cached = BTRFS_CACHE_FINISHED; spin_unlock(&root->cache_lock); root->cache_progress = (u64)-1; btrfs_unpin_free_ino(root); out: wake_up(&root->cache_wait); mutex_unlock(&root->fs_commit_mutex); btrfs_free_path(path); return ret; } static void start_caching(struct btrfs_root *root) { struct btrfs_free_space_ctl *ctl = root->free_ino_ctl; struct task_struct *tsk; int ret; u64 objectid; if (!btrfs_test_opt(root, INODE_MAP_CACHE)) return; spin_lock(&root->cache_lock); if (root->cached != BTRFS_CACHE_NO) { spin_unlock(&root->cache_lock); return; } root->cached = BTRFS_CACHE_STARTED; spin_unlock(&root->cache_lock); ret = load_free_ino_cache(root->fs_info, root); if (ret == 1) { spin_lock(&root->cache_lock); root->cached = BTRFS_CACHE_FINISHED; spin_unlock(&root->cache_lock); return; } /* * It can be quite time-consuming to fill the cache by searching * through the extent tree, and this can keep ino allocation path * waiting. Therefore at start we quickly find out the highest * inode number and we know we can use inode numbers which fall in * [highest_ino + 1, BTRFS_LAST_FREE_OBJECTID]. */ ret = btrfs_find_free_objectid(root, &objectid); if (!ret && objectid <= BTRFS_LAST_FREE_OBJECTID) { __btrfs_add_free_space(ctl, objectid, BTRFS_LAST_FREE_OBJECTID - objectid + 1); } tsk = kthread_run(caching_kthread, root, "btrfs-ino-cache-%llu\n", root->root_key.objectid); BUG_ON(IS_ERR(tsk)); } int btrfs_find_free_ino(struct btrfs_root *root, u64 *objectid) { if (!btrfs_test_opt(root, INODE_MAP_CACHE)) return btrfs_find_free_objectid(root, objectid); again: *objectid = btrfs_find_ino_for_alloc(root); if (*objectid != 0) return 0; start_caching(root); wait_event(root->cache_wait, root->cached == BTRFS_CACHE_FINISHED || root->free_ino_ctl->free_space > 0); if (root->cached == BTRFS_CACHE_FINISHED && root->free_ino_ctl->free_space == 0) return -ENOSPC; else goto again; } void btrfs_return_ino(struct btrfs_root *root, u64 objectid) { struct btrfs_free_space_ctl *ctl = root->free_ino_ctl; struct btrfs_free_space_ctl *pinned = root->free_ino_pinned; if (!btrfs_test_opt(root, INODE_MAP_CACHE)) return; again: if (root->cached == BTRFS_CACHE_FINISHED) { __btrfs_add_free_space(ctl, objectid, 1); } else { /* * If we are in the process of caching free ino chunks, * to avoid adding the same inode number to the free_ino * tree twice due to cross transaction, we'll leave it * in the pinned tree until a transaction is committed * or the caching work is done. */ mutex_lock(&root->fs_commit_mutex); spin_lock(&root->cache_lock); if (root->cached == BTRFS_CACHE_FINISHED) { spin_unlock(&root->cache_lock); mutex_unlock(&root->fs_commit_mutex); goto again; } spin_unlock(&root->cache_lock); start_caching(root); if (objectid <= root->cache_progress || objectid > root->highest_objectid) __btrfs_add_free_space(ctl, objectid, 1); else __btrfs_add_free_space(pinned, objectid, 1); mutex_unlock(&root->fs_commit_mutex); } } /* * When a transaction is committed, we'll move those inode numbers which * are smaller than root->cache_progress from pinned tree to free_ino tree, * and others will just be dropped, because the commit root we were * searching has changed. * * Must be called with root->fs_commit_mutex held */ void btrfs_unpin_free_ino(struct btrfs_root *root) { struct btrfs_free_space_ctl *ctl = root->free_ino_ctl; struct rb_root *rbroot = &root->free_ino_pinned->free_space_offset; struct btrfs_free_space *info; struct rb_node *n; u64 count; if (!btrfs_test_opt(root, INODE_MAP_CACHE)) return; while (1) { n = rb_first(rbroot); if (!n) break; info = rb_entry(n, struct btrfs_free_space, offset_index); BUG_ON(info->bitmap); if (info->offset > root->cache_progress) goto free; else if (info->offset + info->bytes > root->cache_progress) count = root->cache_progress - info->offset + 1; else count = info->bytes; __btrfs_add_free_space(ctl, info->offset, count); free: rb_erase(&info->offset_index, rbroot); kfree(info); } } #define INIT_THRESHOLD (((1024 * 32) / 2) / sizeof(struct btrfs_free_space)) #define INODES_PER_BITMAP (PAGE_CACHE_SIZE * 8) /* * The goal is to keep the memory used by the free_ino tree won't * exceed the memory if we use bitmaps only. */ static void recalculate_thresholds(struct btrfs_free_space_ctl *ctl) { struct btrfs_free_space *info; struct rb_node *n; int max_ino; int max_bitmaps; n = rb_last(&ctl->free_space_offset); if (!n) { ctl->extents_thresh = INIT_THRESHOLD; return; } info = rb_entry(n, struct btrfs_free_space, offset_index); /* * Find the maximum inode number in the filesystem. Note we * ignore the fact that this can be a bitmap, because we are * not doing precise calculation. */ max_ino = info->bytes - 1; max_bitmaps = ALIGN(max_ino, INODES_PER_BITMAP) / INODES_PER_BITMAP; if (max_bitmaps <= ctl->total_bitmaps) { ctl->extents_thresh = 0; return; } ctl->extents_thresh = (max_bitmaps - ctl->total_bitmaps) * PAGE_CACHE_SIZE / sizeof(*info); } /* * We don't fall back to bitmap, if we are below the extents threshold * or this chunk of inode numbers is a big one. */ static bool use_bitmap(struct btrfs_free_space_ctl *ctl, struct btrfs_free_space *info) { if (ctl->free_extents < ctl->extents_thresh || info->bytes > INODES_PER_BITMAP / 10) return false; return true; } static struct btrfs_free_space_op free_ino_op = { .recalc_thresholds = recalculate_thresholds, .use_bitmap = use_bitmap, }; static void pinned_recalc_thresholds(struct btrfs_free_space_ctl *ctl) { } static bool pinned_use_bitmap(struct btrfs_free_space_ctl *ctl, struct btrfs_free_space *info) { /* * We always use extents for two reasons: * * - The pinned tree is only used during the process of caching * work. * - Make code simpler. See btrfs_unpin_free_ino(). */ return false; } static struct btrfs_free_space_op pinned_free_ino_op = { .recalc_thresholds = pinned_recalc_thresholds, .use_bitmap = pinned_use_bitmap, }; void btrfs_init_free_ino_ctl(struct btrfs_root *root) { struct btrfs_free_space_ctl *ctl = root->free_ino_ctl; struct btrfs_free_space_ctl *pinned = root->free_ino_pinned; spin_lock_init(&ctl->tree_lock); ctl->unit = 1; ctl->start = 0; ctl->private = NULL; ctl->op = &free_ino_op; /* * Initially we allow to use 16K of ram to cache chunks of * inode numbers before we resort to bitmaps. This is somewhat * arbitrary, but it will be adjusted in runtime. */ ctl->extents_thresh = INIT_THRESHOLD; spin_lock_init(&pinned->tree_lock); pinned->unit = 1; pinned->start = 0; pinned->private = NULL; pinned->extents_thresh = 0; pinned->op = &pinned_free_ino_op; } int btrfs_save_ino_cache(struct btrfs_root *root, struct btrfs_trans_handle *trans) { struct btrfs_free_space_ctl *ctl = root->free_ino_ctl; struct btrfs_path *path; struct inode *inode; struct btrfs_block_rsv *rsv; u64 num_bytes; u64 alloc_hint = 0; int ret; int prealloc; bool retry = false; /* only fs tree and subvol/snap needs ino cache */ if (root->root_key.objectid != BTRFS_FS_TREE_OBJECTID && (root->root_key.objectid < BTRFS_FIRST_FREE_OBJECTID || root->root_key.objectid > BTRFS_LAST_FREE_OBJECTID)) return 0; /* Don't save inode cache if we are deleting this root */ if (btrfs_root_refs(&root->root_item) == 0 && root != root->fs_info->tree_root) return 0; if (!btrfs_test_opt(root, INODE_MAP_CACHE)) return 0; path = btrfs_alloc_path(); if (!path) return -ENOMEM; rsv = trans->block_rsv; trans->block_rsv = &root->fs_info->trans_block_rsv; num_bytes = trans->bytes_reserved; /* * 1 item for inode item insertion if need * 3 items for inode item update (in the worst case) * 1 item for free space object * 3 items for pre-allocation */ trans->bytes_reserved = btrfs_calc_trans_metadata_size(root, 8); ret = btrfs_block_rsv_add_noflush(root, trans->block_rsv, trans->bytes_reserved); if (ret) goto out; again: inode = lookup_free_ino_inode(root, path); if (IS_ERR(inode) && PTR_ERR(inode) != -ENOENT) { ret = PTR_ERR(inode); goto out_release; } if (IS_ERR(inode)) { BUG_ON(retry); retry = true; ret = create_free_ino_inode(root, trans, path); if (ret) goto out_release; goto again; } BTRFS_I(inode)->generation = 0; ret = btrfs_update_inode(trans, root, inode); WARN_ON(ret); if (i_size_read(inode) > 0) { ret = btrfs_truncate_free_space_cache(root, trans, path, inode); if (ret) goto out_put; } spin_lock(&root->cache_lock); if (root->cached != BTRFS_CACHE_FINISHED) { ret = -1; spin_unlock(&root->cache_lock); goto out_put; } spin_unlock(&root->cache_lock); spin_lock(&ctl->tree_lock); prealloc = sizeof(struct btrfs_free_space) * ctl->free_extents; prealloc = ALIGN(prealloc, PAGE_CACHE_SIZE); prealloc += ctl->total_bitmaps * PAGE_CACHE_SIZE; spin_unlock(&ctl->tree_lock); /* Just to make sure we have enough space */ prealloc += 8 * PAGE_CACHE_SIZE; ret = btrfs_delalloc_reserve_space(inode, prealloc); if (ret) goto out_put; ret = btrfs_prealloc_file_range_trans(inode, trans, 0, 0, prealloc, prealloc, prealloc, &alloc_hint); if (ret) { btrfs_delalloc_release_space(inode, prealloc); goto out_put; } btrfs_free_reserved_data_space(inode, prealloc); ret = btrfs_write_out_ino_cache(root, trans, path); out_put: iput(inode); out_release: btrfs_block_rsv_release(root, trans->block_rsv, trans->bytes_reserved); out: trans->block_rsv = rsv; trans->bytes_reserved = num_bytes; btrfs_free_path(path); return ret; } static int btrfs_find_highest_objectid(struct btrfs_root *root, u64 *objectid) { struct btrfs_path *path; int ret; struct extent_buffer *l; struct btrfs_key search_key; struct btrfs_key found_key; int slot; path = btrfs_alloc_path(); if (!path) return -ENOMEM; search_key.objectid = BTRFS_LAST_FREE_OBJECTID; search_key.type = -1; search_key.offset = (u64)-1; ret = btrfs_search_slot(NULL, root, &search_key, path, 0, 0); if (ret < 0) goto error; BUG_ON(ret == 0); if (path->slots[0] > 0) { slot = path->slots[0] - 1; l = path->nodes[0]; btrfs_item_key_to_cpu(l, &found_key, slot); *objectid = max_t(u64, found_key.objectid, BTRFS_FIRST_FREE_OBJECTID - 1); } else { *objectid = BTRFS_FIRST_FREE_OBJECTID - 1; } ret = 0; error: btrfs_free_path(path); return ret; } int btrfs_find_free_objectid(struct btrfs_root *root, u64 *objectid) { int ret; mutex_lock(&root->objectid_mutex); if (unlikely(root->highest_objectid < BTRFS_FIRST_FREE_OBJECTID)) { ret = btrfs_find_highest_objectid(root, &root->highest_objectid); if (ret) goto out; } if (unlikely(root->highest_objectid >= BTRFS_LAST_FREE_OBJECTID)) { ret = -ENOSPC; goto out; } *objectid = ++root->highest_objectid; ret = 0; out: mutex_unlock(&root->objectid_mutex); return ret; }