diff options
Diffstat (limited to 'fs/btrfs/inode-map.c')
-rw-r--r-- | fs/btrfs/inode-map.c | 575 |
1 files changed, 575 insertions, 0 deletions
diff --git a/fs/btrfs/inode-map.c b/fs/btrfs/inode-map.c new file mode 100644 index 000000000..d4a582ac3 --- /dev/null +++ b/fs/btrfs/inode-map.c @@ -0,0 +1,575 @@ +/* + * 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 */ + down_read(&fs_info->commit_root_sem); + + 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 (WARN_ON(btrfs_header_nritems(leaf) == 0)) + 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->ino_cache_progress = last; + up_read(&fs_info->commit_root_sem); + 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->ino_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->ino_cache_lock); + root->ino_cache_state = BTRFS_CACHE_FINISHED; + spin_unlock(&root->ino_cache_lock); + + root->ino_cache_progress = (u64)-1; + btrfs_unpin_free_ino(root); +out: + wake_up(&root->ino_cache_wait); + up_read(&fs_info->commit_root_sem); + + 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->ino_cache_lock); + if (root->ino_cache_state != BTRFS_CACHE_NO) { + spin_unlock(&root->ino_cache_lock); + return; + } + + root->ino_cache_state = BTRFS_CACHE_STARTED; + spin_unlock(&root->ino_cache_lock); + + ret = load_free_ino_cache(root->fs_info, root); + if (ret == 1) { + spin_lock(&root->ino_cache_lock); + root->ino_cache_state = BTRFS_CACHE_FINISHED; + spin_unlock(&root->ino_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", + root->root_key.objectid); + if (IS_ERR(tsk)) { + btrfs_warn(root->fs_info, "failed to start inode caching task"); + btrfs_clear_pending_and_info(root->fs_info, INODE_MAP_CACHE, + "disabling inode map caching"); + } +} + +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->ino_cache_wait, + root->ino_cache_state == BTRFS_CACHE_FINISHED || + root->free_ino_ctl->free_space > 0); + + if (root->ino_cache_state == 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 *pinned = root->free_ino_pinned; + + if (!btrfs_test_opt(root, INODE_MAP_CACHE)) + return; +again: + if (root->ino_cache_state == BTRFS_CACHE_FINISHED) { + __btrfs_add_free_space(pinned, objectid, 1); + } else { + down_write(&root->fs_info->commit_root_sem); + spin_lock(&root->ino_cache_lock); + if (root->ino_cache_state == BTRFS_CACHE_FINISHED) { + spin_unlock(&root->ino_cache_lock); + up_write(&root->fs_info->commit_root_sem); + goto again; + } + spin_unlock(&root->ino_cache_lock); + + start_caching(root); + + __btrfs_add_free_space(pinned, objectid, 1); + + up_write(&root->fs_info->commit_root_sem); + } +} + +/* + * When a transaction is committed, we'll move those inode numbers which are + * smaller than root->ino_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_info->commit_root_sem 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; + spinlock_t *rbroot_lock = &root->free_ino_pinned->tree_lock; + struct btrfs_free_space *info; + struct rb_node *n; + u64 count; + + if (!btrfs_test_opt(root, INODE_MAP_CACHE)) + return; + + while (1) { + bool add_to_ctl = true; + + spin_lock(rbroot_lock); + n = rb_first(rbroot); + if (!n) { + spin_unlock(rbroot_lock); + break; + } + + info = rb_entry(n, struct btrfs_free_space, offset_index); + BUG_ON(info->bitmap); /* Logic error */ + + if (info->offset > root->ino_cache_progress) + add_to_ctl = false; + else if (info->offset + info->bytes > root->ino_cache_progress) + count = root->ino_cache_progress - info->offset + 1; + else + count = info->bytes; + + rb_erase(&info->offset_index, rbroot); + spin_unlock(rbroot_lock); + if (add_to_ctl) + __btrfs_add_free_space(ctl, info->offset, count); + kmem_cache_free(btrfs_free_space_cachep, 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; + INIT_LIST_HEAD(&ctl->trimming_ranges); + mutex_init(&ctl->cache_writeout_mutex); + + /* + * 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) + 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 + * 4 items for inode item update (in the worst case) + * 1 items for slack space if we need do truncation + * 1 item for free space object + * 3 items for pre-allocation + */ + trans->bytes_reserved = btrfs_calc_trans_metadata_size(root, 10); + ret = btrfs_block_rsv_add(root, trans->block_rsv, + trans->bytes_reserved, + BTRFS_RESERVE_NO_FLUSH); + if (ret) + goto out; + trace_btrfs_space_reservation(root->fs_info, "ino_cache", + trans->transid, trans->bytes_reserved, 1); +again: + inode = lookup_free_ino_inode(root, path); + if (IS_ERR(inode) && (PTR_ERR(inode) != -ENOENT || retry)) { + ret = PTR_ERR(inode); + goto out_release; + } + + if (IS_ERR(inode)) { + BUG_ON(retry); /* Logic error */ + 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); + if (ret) { + btrfs_abort_transaction(trans, root, ret); + goto out_put; + } + + if (i_size_read(inode) > 0) { + ret = btrfs_truncate_free_space_cache(root, trans, NULL, inode); + if (ret) { + if (ret != -ENOSPC) + btrfs_abort_transaction(trans, root, ret); + goto out_put; + } + } + + spin_lock(&root->ino_cache_lock); + if (root->ino_cache_state != BTRFS_CACHE_FINISHED) { + ret = -1; + spin_unlock(&root->ino_cache_lock); + goto out_put; + } + spin_unlock(&root->ino_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, inode); +out_put: + iput(inode); +out_release: + trace_btrfs_space_reservation(root->fs_info, "ino_cache", + trans->transid, trans->bytes_reserved, 0); + 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); /* Corruption */ + 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; +} |