diff options
Diffstat (limited to 'fs/btrfs/free-space-cache.c')
| -rw-r--r-- | fs/btrfs/free-space-cache.c | 4334 |
1 files changed, 4334 insertions, 0 deletions
diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c new file mode 100644 index 0000000000..8dd8ef7603 --- /dev/null +++ b/fs/btrfs/free-space-cache.c @@ -0,0 +1,4334 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2008 Red Hat. All rights reserved. + */ + +#include <linux/pagemap.h> +#include <linux/sched.h> +#include <linux/sched/signal.h> +#include <linux/slab.h> +#include <linux/math64.h> +#include <linux/ratelimit.h> +#include <linux/error-injection.h> +#include <linux/sched/mm.h> +#include "ctree.h" +#include "fs.h" +#include "messages.h" +#include "misc.h" +#include "free-space-cache.h" +#include "transaction.h" +#include "disk-io.h" +#include "extent_io.h" +#include "volumes.h" +#include "space-info.h" +#include "delalloc-space.h" +#include "block-group.h" +#include "discard.h" +#include "subpage.h" +#include "inode-item.h" +#include "accessors.h" +#include "file-item.h" +#include "file.h" +#include "super.h" + +#define BITS_PER_BITMAP (PAGE_SIZE * 8UL) +#define MAX_CACHE_BYTES_PER_GIG SZ_64K +#define FORCE_EXTENT_THRESHOLD SZ_1M + +static struct kmem_cache *btrfs_free_space_cachep; +static struct kmem_cache *btrfs_free_space_bitmap_cachep; + +struct btrfs_trim_range { + u64 start; + u64 bytes; + struct list_head list; +}; + +static int link_free_space(struct btrfs_free_space_ctl *ctl, + struct btrfs_free_space *info); +static void unlink_free_space(struct btrfs_free_space_ctl *ctl, + struct btrfs_free_space *info, bool update_stat); +static int search_bitmap(struct btrfs_free_space_ctl *ctl, + struct btrfs_free_space *bitmap_info, u64 *offset, + u64 *bytes, bool for_alloc); +static void free_bitmap(struct btrfs_free_space_ctl *ctl, + struct btrfs_free_space *bitmap_info); +static void bitmap_clear_bits(struct btrfs_free_space_ctl *ctl, + struct btrfs_free_space *info, u64 offset, + u64 bytes, bool update_stats); + +static void __btrfs_remove_free_space_cache(struct btrfs_free_space_ctl *ctl) +{ + struct btrfs_free_space *info; + struct rb_node *node; + + while ((node = rb_last(&ctl->free_space_offset)) != NULL) { + info = rb_entry(node, struct btrfs_free_space, offset_index); + if (!info->bitmap) { + unlink_free_space(ctl, info, true); + kmem_cache_free(btrfs_free_space_cachep, info); + } else { + free_bitmap(ctl, info); + } + + cond_resched_lock(&ctl->tree_lock); + } +} + +static struct inode *__lookup_free_space_inode(struct btrfs_root *root, + struct btrfs_path *path, + u64 offset) +{ + struct btrfs_fs_info *fs_info = root->fs_info; + struct btrfs_key key; + struct btrfs_key location; + struct btrfs_disk_key disk_key; + struct btrfs_free_space_header *header; + struct extent_buffer *leaf; + struct inode *inode = NULL; + unsigned nofs_flag; + int ret; + + key.objectid = BTRFS_FREE_SPACE_OBJECTID; + key.offset = offset; + key.type = 0; + + ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); + if (ret < 0) + return ERR_PTR(ret); + if (ret > 0) { + btrfs_release_path(path); + return ERR_PTR(-ENOENT); + } + + leaf = path->nodes[0]; + header = btrfs_item_ptr(leaf, path->slots[0], + struct btrfs_free_space_header); + btrfs_free_space_key(leaf, header, &disk_key); + btrfs_disk_key_to_cpu(&location, &disk_key); + btrfs_release_path(path); + + /* + * We are often under a trans handle at this point, so we need to make + * sure NOFS is set to keep us from deadlocking. + */ + nofs_flag = memalloc_nofs_save(); + inode = btrfs_iget_path(fs_info->sb, location.objectid, root, path); + btrfs_release_path(path); + memalloc_nofs_restore(nofs_flag); + if (IS_ERR(inode)) + return inode; + + mapping_set_gfp_mask(inode->i_mapping, + mapping_gfp_constraint(inode->i_mapping, + ~(__GFP_FS | __GFP_HIGHMEM))); + + return inode; +} + +struct inode *lookup_free_space_inode(struct btrfs_block_group *block_group, + struct btrfs_path *path) +{ + struct btrfs_fs_info *fs_info = block_group->fs_info; + struct inode *inode = NULL; + u32 flags = BTRFS_INODE_NODATASUM | BTRFS_INODE_NODATACOW; + + spin_lock(&block_group->lock); + if (block_group->inode) + inode = igrab(block_group->inode); + spin_unlock(&block_group->lock); + if (inode) + return inode; + + inode = __lookup_free_space_inode(fs_info->tree_root, path, + block_group->start); + if (IS_ERR(inode)) + return inode; + + spin_lock(&block_group->lock); + if (!((BTRFS_I(inode)->flags & flags) == flags)) { + btrfs_info(fs_info, "Old style space inode found, converting."); + BTRFS_I(inode)->flags |= BTRFS_INODE_NODATASUM | + BTRFS_INODE_NODATACOW; + block_group->disk_cache_state = BTRFS_DC_CLEAR; + } + + if (!test_and_set_bit(BLOCK_GROUP_FLAG_IREF, &block_group->runtime_flags)) + block_group->inode = igrab(inode); + spin_unlock(&block_group->lock); + + return inode; +} + +static int __create_free_space_inode(struct btrfs_root *root, + struct btrfs_trans_handle *trans, + struct btrfs_path *path, + u64 ino, u64 offset) +{ + struct btrfs_key key; + struct btrfs_disk_key disk_key; + struct btrfs_free_space_header *header; + struct btrfs_inode_item *inode_item; + struct extent_buffer *leaf; + /* We inline CRCs for the free disk space cache */ + const u64 flags = BTRFS_INODE_NOCOMPRESS | BTRFS_INODE_PREALLOC | + BTRFS_INODE_NODATASUM | BTRFS_INODE_NODATACOW; + int ret; + + ret = btrfs_insert_empty_inode(trans, root, path, ino); + if (ret) + return ret; + + leaf = path->nodes[0]; + inode_item = btrfs_item_ptr(leaf, path->slots[0], + struct btrfs_inode_item); + btrfs_item_key(leaf, &disk_key, path->slots[0]); + memzero_extent_buffer(leaf, (unsigned long)inode_item, + sizeof(*inode_item)); + btrfs_set_inode_generation(leaf, inode_item, trans->transid); + btrfs_set_inode_size(leaf, inode_item, 0); + btrfs_set_inode_nbytes(leaf, inode_item, 0); + btrfs_set_inode_uid(leaf, inode_item, 0); + btrfs_set_inode_gid(leaf, inode_item, 0); + btrfs_set_inode_mode(leaf, inode_item, S_IFREG | 0600); + btrfs_set_inode_flags(leaf, inode_item, flags); + btrfs_set_inode_nlink(leaf, inode_item, 1); + btrfs_set_inode_transid(leaf, inode_item, trans->transid); + btrfs_set_inode_block_group(leaf, inode_item, offset); + btrfs_mark_buffer_dirty(trans, leaf); + btrfs_release_path(path); + + key.objectid = BTRFS_FREE_SPACE_OBJECTID; + key.offset = offset; + key.type = 0; + ret = btrfs_insert_empty_item(trans, root, path, &key, + sizeof(struct btrfs_free_space_header)); + if (ret < 0) { + btrfs_release_path(path); + return ret; + } + + leaf = path->nodes[0]; + header = btrfs_item_ptr(leaf, path->slots[0], + struct btrfs_free_space_header); + memzero_extent_buffer(leaf, (unsigned long)header, sizeof(*header)); + btrfs_set_free_space_key(leaf, header, &disk_key); + btrfs_mark_buffer_dirty(trans, leaf); + btrfs_release_path(path); + + return 0; +} + +int create_free_space_inode(struct btrfs_trans_handle *trans, + struct btrfs_block_group *block_group, + struct btrfs_path *path) +{ + int ret; + u64 ino; + + ret = btrfs_get_free_objectid(trans->fs_info->tree_root, &ino); + if (ret < 0) + return ret; + + return __create_free_space_inode(trans->fs_info->tree_root, trans, path, + ino, block_group->start); +} + +/* + * inode is an optional sink: if it is NULL, btrfs_remove_free_space_inode + * handles lookup, otherwise it takes ownership and iputs the inode. + * Don't reuse an inode pointer after passing it into this function. + */ +int btrfs_remove_free_space_inode(struct btrfs_trans_handle *trans, + struct inode *inode, + struct btrfs_block_group *block_group) +{ + struct btrfs_path *path; + struct btrfs_key key; + int ret = 0; + + path = btrfs_alloc_path(); + if (!path) + return -ENOMEM; + + if (!inode) + inode = lookup_free_space_inode(block_group, path); + if (IS_ERR(inode)) { + if (PTR_ERR(inode) != -ENOENT) + ret = PTR_ERR(inode); + goto out; + } + ret = btrfs_orphan_add(trans, BTRFS_I(inode)); + if (ret) { + btrfs_add_delayed_iput(BTRFS_I(inode)); + goto out; + } + clear_nlink(inode); + /* One for the block groups ref */ + spin_lock(&block_group->lock); + if (test_and_clear_bit(BLOCK_GROUP_FLAG_IREF, &block_group->runtime_flags)) { + block_group->inode = NULL; + spin_unlock(&block_group->lock); + iput(inode); + } else { + spin_unlock(&block_group->lock); + } + /* One for the lookup ref */ + btrfs_add_delayed_iput(BTRFS_I(inode)); + + key.objectid = BTRFS_FREE_SPACE_OBJECTID; + key.type = 0; + key.offset = block_group->start; + ret = btrfs_search_slot(trans, trans->fs_info->tree_root, &key, path, + -1, 1); + if (ret) { + if (ret > 0) + ret = 0; + goto out; + } + ret = btrfs_del_item(trans, trans->fs_info->tree_root, path); +out: + btrfs_free_path(path); + return ret; +} + +int btrfs_truncate_free_space_cache(struct btrfs_trans_handle *trans, + struct btrfs_block_group *block_group, + struct inode *vfs_inode) +{ + struct btrfs_truncate_control control = { + .inode = BTRFS_I(vfs_inode), + .new_size = 0, + .ino = btrfs_ino(BTRFS_I(vfs_inode)), + .min_type = BTRFS_EXTENT_DATA_KEY, + .clear_extent_range = true, + }; + struct btrfs_inode *inode = BTRFS_I(vfs_inode); + struct btrfs_root *root = inode->root; + struct extent_state *cached_state = NULL; + int ret = 0; + bool locked = false; + + if (block_group) { + struct btrfs_path *path = btrfs_alloc_path(); + + if (!path) { + ret = -ENOMEM; + goto fail; + } + locked = true; + mutex_lock(&trans->transaction->cache_write_mutex); + if (!list_empty(&block_group->io_list)) { + list_del_init(&block_group->io_list); + + btrfs_wait_cache_io(trans, block_group, path); + btrfs_put_block_group(block_group); + } + + /* + * now that we've truncated the cache away, its no longer + * setup or written + */ + spin_lock(&block_group->lock); + block_group->disk_cache_state = BTRFS_DC_CLEAR; + spin_unlock(&block_group->lock); + btrfs_free_path(path); + } + + btrfs_i_size_write(inode, 0); + truncate_pagecache(vfs_inode, 0); + + lock_extent(&inode->io_tree, 0, (u64)-1, &cached_state); + btrfs_drop_extent_map_range(inode, 0, (u64)-1, false); + + /* + * We skip the throttling logic for free space cache inodes, so we don't + * need to check for -EAGAIN. + */ + ret = btrfs_truncate_inode_items(trans, root, &control); + + inode_sub_bytes(&inode->vfs_inode, control.sub_bytes); + btrfs_inode_safe_disk_i_size_write(inode, control.last_size); + + unlock_extent(&inode->io_tree, 0, (u64)-1, &cached_state); + if (ret) + goto fail; + + ret = btrfs_update_inode(trans, root, inode); + +fail: + if (locked) + mutex_unlock(&trans->transaction->cache_write_mutex); + if (ret) + btrfs_abort_transaction(trans, ret); + + return ret; +} + +static void readahead_cache(struct inode *inode) +{ + struct file_ra_state ra; + unsigned long last_index; + + file_ra_state_init(&ra, inode->i_mapping); + last_index = (i_size_read(inode) - 1) >> PAGE_SHIFT; + + page_cache_sync_readahead(inode->i_mapping, &ra, NULL, 0, last_index); +} + +static int io_ctl_init(struct btrfs_io_ctl *io_ctl, struct inode *inode, + int write) +{ + int num_pages; + + num_pages = DIV_ROUND_UP(i_size_read(inode), PAGE_SIZE); + + /* Make sure we can fit our crcs and generation into the first page */ + if (write && (num_pages * sizeof(u32) + sizeof(u64)) > PAGE_SIZE) + return -ENOSPC; + + memset(io_ctl, 0, sizeof(struct btrfs_io_ctl)); + + io_ctl->pages = kcalloc(num_pages, sizeof(struct page *), GFP_NOFS); + if (!io_ctl->pages) + return -ENOMEM; + + io_ctl->num_pages = num_pages; + io_ctl->fs_info = btrfs_sb(inode->i_sb); + io_ctl->inode = inode; + + return 0; +} +ALLOW_ERROR_INJECTION(io_ctl_init, ERRNO); + +static void io_ctl_free(struct btrfs_io_ctl *io_ctl) +{ + kfree(io_ctl->pages); + io_ctl->pages = NULL; +} + +static void io_ctl_unmap_page(struct btrfs_io_ctl *io_ctl) +{ + if (io_ctl->cur) { + io_ctl->cur = NULL; + io_ctl->orig = NULL; + } +} + +static void io_ctl_map_page(struct btrfs_io_ctl *io_ctl, int clear) +{ + ASSERT(io_ctl->index < io_ctl->num_pages); + io_ctl->page = io_ctl->pages[io_ctl->index++]; + io_ctl->cur = page_address(io_ctl->page); + io_ctl->orig = io_ctl->cur; + io_ctl->size = PAGE_SIZE; + if (clear) + clear_page(io_ctl->cur); +} + +static void io_ctl_drop_pages(struct btrfs_io_ctl *io_ctl) +{ + int i; + + io_ctl_unmap_page(io_ctl); + + for (i = 0; i < io_ctl->num_pages; i++) { + if (io_ctl->pages[i]) { + btrfs_page_clear_checked(io_ctl->fs_info, + io_ctl->pages[i], + page_offset(io_ctl->pages[i]), + PAGE_SIZE); + unlock_page(io_ctl->pages[i]); + put_page(io_ctl->pages[i]); + } + } +} + +static int io_ctl_prepare_pages(struct btrfs_io_ctl *io_ctl, bool uptodate) +{ + struct page *page; + struct inode *inode = io_ctl->inode; + gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping); + int i; + + for (i = 0; i < io_ctl->num_pages; i++) { + int ret; + + page = find_or_create_page(inode->i_mapping, i, mask); + if (!page) { + io_ctl_drop_pages(io_ctl); + return -ENOMEM; + } + + ret = set_page_extent_mapped(page); + if (ret < 0) { + unlock_page(page); + put_page(page); + io_ctl_drop_pages(io_ctl); + return ret; + } + + io_ctl->pages[i] = page; + if (uptodate && !PageUptodate(page)) { + btrfs_read_folio(NULL, page_folio(page)); + lock_page(page); + if (page->mapping != inode->i_mapping) { + btrfs_err(BTRFS_I(inode)->root->fs_info, + "free space cache page truncated"); + io_ctl_drop_pages(io_ctl); + return -EIO; + } + if (!PageUptodate(page)) { + btrfs_err(BTRFS_I(inode)->root->fs_info, + "error reading free space cache"); + io_ctl_drop_pages(io_ctl); + return -EIO; + } + } + } + + for (i = 0; i < io_ctl->num_pages; i++) + clear_page_dirty_for_io(io_ctl->pages[i]); + + return 0; +} + +static void io_ctl_set_generation(struct btrfs_io_ctl *io_ctl, u64 generation) +{ + io_ctl_map_page(io_ctl, 1); + + /* + * Skip the csum areas. If we don't check crcs then we just have a + * 64bit chunk at the front of the first page. + */ + io_ctl->cur += (sizeof(u32) * io_ctl->num_pages); + io_ctl->size -= sizeof(u64) + (sizeof(u32) * io_ctl->num_pages); + + put_unaligned_le64(generation, io_ctl->cur); + io_ctl->cur += sizeof(u64); +} + +static int io_ctl_check_generation(struct btrfs_io_ctl *io_ctl, u64 generation) +{ + u64 cache_gen; + + /* + * Skip the crc area. If we don't check crcs then we just have a 64bit + * chunk at the front of the first page. + */ + io_ctl->cur += sizeof(u32) * io_ctl->num_pages; + io_ctl->size -= sizeof(u64) + (sizeof(u32) * io_ctl->num_pages); + + cache_gen = get_unaligned_le64(io_ctl->cur); + if (cache_gen != generation) { + btrfs_err_rl(io_ctl->fs_info, + "space cache generation (%llu) does not match inode (%llu)", + cache_gen, generation); + io_ctl_unmap_page(io_ctl); + return -EIO; + } + io_ctl->cur += sizeof(u64); + return 0; +} + +static void io_ctl_set_crc(struct btrfs_io_ctl *io_ctl, int index) +{ + u32 *tmp; + u32 crc = ~(u32)0; + unsigned offset = 0; + + if (index == 0) + offset = sizeof(u32) * io_ctl->num_pages; + + crc = btrfs_crc32c(crc, io_ctl->orig + offset, PAGE_SIZE - offset); + btrfs_crc32c_final(crc, (u8 *)&crc); + io_ctl_unmap_page(io_ctl); + tmp = page_address(io_ctl->pages[0]); + tmp += index; + *tmp = crc; +} + +static int io_ctl_check_crc(struct btrfs_io_ctl *io_ctl, int index) +{ + u32 *tmp, val; + u32 crc = ~(u32)0; + unsigned offset = 0; + + if (index == 0) + offset = sizeof(u32) * io_ctl->num_pages; + + tmp = page_address(io_ctl->pages[0]); + tmp += index; + val = *tmp; + + io_ctl_map_page(io_ctl, 0); + crc = btrfs_crc32c(crc, io_ctl->orig + offset, PAGE_SIZE - offset); + btrfs_crc32c_final(crc, (u8 *)&crc); + if (val != crc) { + btrfs_err_rl(io_ctl->fs_info, + "csum mismatch on free space cache"); + io_ctl_unmap_page(io_ctl); + return -EIO; + } + + return 0; +} + +static int io_ctl_add_entry(struct btrfs_io_ctl *io_ctl, u64 offset, u64 bytes, + void *bitmap) +{ + struct btrfs_free_space_entry *entry; + + if (!io_ctl->cur) + return -ENOSPC; + + entry = io_ctl->cur; + put_unaligned_le64(offset, &entry->offset); + put_unaligned_le64(bytes, &entry->bytes); + entry->type = (bitmap) ? BTRFS_FREE_SPACE_BITMAP : + BTRFS_FREE_SPACE_EXTENT; + io_ctl->cur += sizeof(struct btrfs_free_space_entry); + io_ctl->size -= sizeof(struct btrfs_free_space_entry); + + if (io_ctl->size >= sizeof(struct btrfs_free_space_entry)) + return 0; + + io_ctl_set_crc(io_ctl, io_ctl->index - 1); + + /* No more pages to map */ + if (io_ctl->index >= io_ctl->num_pages) + return 0; + + /* map the next page */ + io_ctl_map_page(io_ctl, 1); + return 0; +} + +static int io_ctl_add_bitmap(struct btrfs_io_ctl *io_ctl, void *bitmap) +{ + if (!io_ctl->cur) + return -ENOSPC; + + /* + * If we aren't at the start of the current page, unmap this one and + * map the next one if there is any left. + */ + if (io_ctl->cur != io_ctl->orig) { + io_ctl_set_crc(io_ctl, io_ctl->index - 1); + if (io_ctl->index >= io_ctl->num_pages) + return -ENOSPC; + io_ctl_map_page(io_ctl, 0); + } + + copy_page(io_ctl->cur, bitmap); + io_ctl_set_crc(io_ctl, io_ctl->index - 1); + if (io_ctl->index < io_ctl->num_pages) + io_ctl_map_page(io_ctl, 0); + return 0; +} + +static void io_ctl_zero_remaining_pages(struct btrfs_io_ctl *io_ctl) +{ + /* + * If we're not on the boundary we know we've modified the page and we + * need to crc the page. + */ + if (io_ctl->cur != io_ctl->orig) + io_ctl_set_crc(io_ctl, io_ctl->index - 1); + else + io_ctl_unmap_page(io_ctl); + + while (io_ctl->index < io_ctl->num_pages) { + io_ctl_map_page(io_ctl, 1); + io_ctl_set_crc(io_ctl, io_ctl->index - 1); + } +} + +static int io_ctl_read_entry(struct btrfs_io_ctl *io_ctl, + struct btrfs_free_space *entry, u8 *type) +{ + struct btrfs_free_space_entry *e; + int ret; + + if (!io_ctl->cur) { + ret = io_ctl_check_crc(io_ctl, io_ctl->index); + if (ret) + return ret; + } + + e = io_ctl->cur; + entry->offset = get_unaligned_le64(&e->offset); + entry->bytes = get_unaligned_le64(&e->bytes); + *type = e->type; + io_ctl->cur += sizeof(struct btrfs_free_space_entry); + io_ctl->size -= sizeof(struct btrfs_free_space_entry); + + if (io_ctl->size >= sizeof(struct btrfs_free_space_entry)) + return 0; + + io_ctl_unmap_page(io_ctl); + + return 0; +} + +static int io_ctl_read_bitmap(struct btrfs_io_ctl *io_ctl, + struct btrfs_free_space *entry) +{ + int ret; + + ret = io_ctl_check_crc(io_ctl, io_ctl->index); + if (ret) + return ret; + + copy_page(entry->bitmap, io_ctl->cur); + io_ctl_unmap_page(io_ctl); + + return 0; +} + +static void recalculate_thresholds(struct btrfs_free_space_ctl *ctl) +{ + struct btrfs_block_group *block_group = ctl->block_group; + u64 max_bytes; + u64 bitmap_bytes; + u64 extent_bytes; + u64 size = block_group->length; + u64 bytes_per_bg = BITS_PER_BITMAP * ctl->unit; + u64 max_bitmaps = div64_u64(size + bytes_per_bg - 1, bytes_per_bg); + + max_bitmaps = max_t(u64, max_bitmaps, 1); + + if (ctl->total_bitmaps > max_bitmaps) + btrfs_err(block_group->fs_info, +"invalid free space control: bg start=%llu len=%llu total_bitmaps=%u unit=%u max_bitmaps=%llu bytes_per_bg=%llu", + block_group->start, block_group->length, + ctl->total_bitmaps, ctl->unit, max_bitmaps, + bytes_per_bg); + ASSERT(ctl->total_bitmaps <= max_bitmaps); + + /* + * We are trying to keep the total amount of memory used per 1GiB of + * space to be MAX_CACHE_BYTES_PER_GIG. However, with a reclamation + * mechanism of pulling extents >= FORCE_EXTENT_THRESHOLD out of + * bitmaps, we may end up using more memory than this. + */ + if (size < SZ_1G) + max_bytes = MAX_CACHE_BYTES_PER_GIG; + else + max_bytes = MAX_CACHE_BYTES_PER_GIG * div_u64(size, SZ_1G); + + bitmap_bytes = ctl->total_bitmaps * ctl->unit; + + /* + * we want the extent entry threshold to always be at most 1/2 the max + * bytes we can have, or whatever is less than that. + */ + extent_bytes = max_bytes - bitmap_bytes; + extent_bytes = min_t(u64, extent_bytes, max_bytes >> 1); + + ctl->extents_thresh = + div_u64(extent_bytes, sizeof(struct btrfs_free_space)); +} + +static int __load_free_space_cache(struct btrfs_root *root, struct inode *inode, + struct btrfs_free_space_ctl *ctl, + struct btrfs_path *path, u64 offset) +{ + struct btrfs_fs_info *fs_info = root->fs_info; + struct btrfs_free_space_header *header; + struct extent_buffer *leaf; + struct btrfs_io_ctl io_ctl; + struct btrfs_key key; + struct btrfs_free_space *e, *n; + LIST_HEAD(bitmaps); + u64 num_entries; + u64 num_bitmaps; + u64 generation; + u8 type; + int ret = 0; + + /* Nothing in the space cache, goodbye */ + if (!i_size_read(inode)) + return 0; + + key.objectid = BTRFS_FREE_SPACE_OBJECTID; + key.offset = offset; + key.type = 0; + + ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); + if (ret < 0) + return 0; + else if (ret > 0) { + btrfs_release_path(path); + return 0; + } + + ret = -1; + + leaf = path->nodes[0]; + header = btrfs_item_ptr(leaf, path->slots[0], + struct btrfs_free_space_header); + num_entries = btrfs_free_space_entries(leaf, header); + num_bitmaps = btrfs_free_space_bitmaps(leaf, header); + generation = btrfs_free_space_generation(leaf, header); + btrfs_release_path(path); + + if (!BTRFS_I(inode)->generation) { + btrfs_info(fs_info, + "the free space cache file (%llu) is invalid, skip it", + offset); + return 0; + } + + if (BTRFS_I(inode)->generation != generation) { + btrfs_err(fs_info, + "free space inode generation (%llu) did not match free space cache generation (%llu)", + BTRFS_I(inode)->generation, generation); + return 0; + } + + if (!num_entries) + return 0; + + ret = io_ctl_init(&io_ctl, inode, 0); + if (ret) + return ret; + + readahead_cache(inode); + + ret = io_ctl_prepare_pages(&io_ctl, true); + if (ret) + goto out; + + ret = io_ctl_check_crc(&io_ctl, 0); + if (ret) + goto free_cache; + + ret = io_ctl_check_generation(&io_ctl, generation); + if (ret) + goto free_cache; + + while (num_entries) { + e = kmem_cache_zalloc(btrfs_free_space_cachep, + GFP_NOFS); + if (!e) { + ret = -ENOMEM; + goto free_cache; + } + + ret = io_ctl_read_entry(&io_ctl, e, &type); + if (ret) { + kmem_cache_free(btrfs_free_space_cachep, e); + goto free_cache; + } + + if (!e->bytes) { + ret = -1; + kmem_cache_free(btrfs_free_space_cachep, e); + goto free_cache; + } + + if (type == BTRFS_FREE_SPACE_EXTENT) { + spin_lock(&ctl->tree_lock); + ret = link_free_space(ctl, e); + spin_unlock(&ctl->tree_lock); + if (ret) { + btrfs_err(fs_info, + "Duplicate entries in free space cache, dumping"); + kmem_cache_free(btrfs_free_space_cachep, e); + goto free_cache; + } + } else { + ASSERT(num_bitmaps); + num_bitmaps--; + e->bitmap = kmem_cache_zalloc( + btrfs_free_space_bitmap_cachep, GFP_NOFS); + if (!e->bitmap) { + ret = -ENOMEM; + kmem_cache_free( + btrfs_free_space_cachep, e); + goto free_cache; + } + spin_lock(&ctl->tree_lock); + ret = link_free_space(ctl, e); + if (ret) { + spin_unlock(&ctl->tree_lock); + btrfs_err(fs_info, + "Duplicate entries in free space cache, dumping"); + kmem_cache_free(btrfs_free_space_cachep, e); + goto free_cache; + } + ctl->total_bitmaps++; + recalculate_thresholds(ctl); + spin_unlock(&ctl->tree_lock); + list_add_tail(&e->list, &bitmaps); + } + + num_entries--; + } + + io_ctl_unmap_page(&io_ctl); + + /* + * We add the bitmaps at the end of the entries in order that + * the bitmap entries are added to the cache. + */ + list_for_each_entry_safe(e, n, &bitmaps, list) { + list_del_init(&e->list); + ret = io_ctl_read_bitmap(&io_ctl, e); + if (ret) + goto free_cache; + } + + io_ctl_drop_pages(&io_ctl); + ret = 1; +out: + io_ctl_free(&io_ctl); + return ret; +free_cache: + io_ctl_drop_pages(&io_ctl); + + spin_lock(&ctl->tree_lock); + __btrfs_remove_free_space_cache(ctl); + spin_unlock(&ctl->tree_lock); + goto out; +} + +static int copy_free_space_cache(struct btrfs_block_group *block_group, + struct btrfs_free_space_ctl *ctl) +{ + struct btrfs_free_space *info; + struct rb_node *n; + int ret = 0; + + while (!ret && (n = rb_first(&ctl->free_space_offset)) != NULL) { + info = rb_entry(n, struct btrfs_free_space, offset_index); + if (!info->bitmap) { + const u64 offset = info->offset; + const u64 bytes = info->bytes; + + unlink_free_space(ctl, info, true); + spin_unlock(&ctl->tree_lock); + kmem_cache_free(btrfs_free_space_cachep, info); + ret = btrfs_add_free_space(block_group, offset, bytes); + spin_lock(&ctl->tree_lock); + } else { + u64 offset = info->offset; + u64 bytes = ctl->unit; + + ret = search_bitmap(ctl, info, &offset, &bytes, false); + if (ret == 0) { + bitmap_clear_bits(ctl, info, offset, bytes, true); + spin_unlock(&ctl->tree_lock); + ret = btrfs_add_free_space(block_group, offset, + bytes); + spin_lock(&ctl->tree_lock); + } else { + free_bitmap(ctl, info); + ret = 0; + } + } + cond_resched_lock(&ctl->tree_lock); + } + return ret; +} + +static struct lock_class_key btrfs_free_space_inode_key; + +int load_free_space_cache(struct btrfs_block_group *block_group) +{ + struct btrfs_fs_info *fs_info = block_group->fs_info; + struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl; + struct btrfs_free_space_ctl tmp_ctl = {}; + struct inode *inode; + struct btrfs_path *path; + int ret = 0; + bool matched; + u64 used = block_group->used; + + /* + * Because we could potentially discard our loaded free space, we want + * to load everything into a temporary structure first, and then if it's + * valid copy it all into the actual free space ctl. + */ + btrfs_init_free_space_ctl(block_group, &tmp_ctl); + + /* + * If this block group has been marked to be cleared for one reason or + * another then we can't trust the on disk cache, so just return. + */ + spin_lock(&block_group->lock); + if (block_group->disk_cache_state != BTRFS_DC_WRITTEN) { + spin_unlock(&block_group->lock); + return 0; + } + spin_unlock(&block_group->lock); + + path = btrfs_alloc_path(); + if (!path) + return 0; + path->search_commit_root = 1; + path->skip_locking = 1; + + /* + * We must pass a path with search_commit_root set to btrfs_iget in + * order to avoid a deadlock when allocating extents for the tree root. + * + * When we are COWing an extent buffer from the tree root, when looking + * for a free extent, at extent-tree.c:find_free_extent(), we can find + * block group without its free space cache loaded. When we find one + * we must load its space cache which requires reading its free space + * cache's inode item from the root tree. If this inode item is located + * in the same leaf that we started COWing before, then we end up in + * deadlock on the extent buffer (trying to read lock it when we + * previously write locked it). + * + * It's safe to read the inode item using the commit root because + * block groups, once loaded, stay in memory forever (until they are + * removed) as well as their space caches once loaded. New block groups + * once created get their ->cached field set to BTRFS_CACHE_FINISHED so + * we will never try to read their inode item while the fs is mounted. + */ + inode = lookup_free_space_inode(block_group, path); + if (IS_ERR(inode)) { + btrfs_free_path(path); + return 0; + } + + /* We may have converted the inode and made the cache invalid. */ + spin_lock(&block_group->lock); + if (block_group->disk_cache_state != BTRFS_DC_WRITTEN) { + spin_unlock(&block_group->lock); + btrfs_free_path(path); + goto out; + } + spin_unlock(&block_group->lock); + + /* + * Reinitialize the class of struct inode's mapping->invalidate_lock for + * free space inodes to prevent false positives related to locks for normal + * inodes. + */ + lockdep_set_class(&(&inode->i_data)->invalidate_lock, + &btrfs_free_space_inode_key); + + ret = __load_free_space_cache(fs_info->tree_root, inode, &tmp_ctl, + path, block_group->start); + btrfs_free_path(path); + if (ret <= 0) + goto out; + + matched = (tmp_ctl.free_space == (block_group->length - used - + block_group->bytes_super)); + + if (matched) { + spin_lock(&tmp_ctl.tree_lock); + ret = copy_free_space_cache(block_group, &tmp_ctl); + spin_unlock(&tmp_ctl.tree_lock); + /* + * ret == 1 means we successfully loaded the free space cache, + * so we need to re-set it here. + */ + if (ret == 0) + ret = 1; + } else { + /* + * We need to call the _locked variant so we don't try to update + * the discard counters. + */ + spin_lock(&tmp_ctl.tree_lock); + __btrfs_remove_free_space_cache(&tmp_ctl); + spin_unlock(&tmp_ctl.tree_lock); + btrfs_warn(fs_info, + "block group %llu has wrong amount of free space", + block_group->start); + ret = -1; + } +out: + if (ret < 0) { + /* This cache is bogus, make sure it gets cleared */ + spin_lock(&block_group->lock); + block_group->disk_cache_state = BTRFS_DC_CLEAR; + spin_unlock(&block_group->lock); + ret = 0; + + btrfs_warn(fs_info, + "failed to load free space cache for block group %llu, rebuilding it now", + block_group->start); + } + + spin_lock(&ctl->tree_lock); + btrfs_discard_update_discardable(block_group); + spin_unlock(&ctl->tree_lock); + iput(inode); + return ret; +} + +static noinline_for_stack +int write_cache_extent_entries(struct btrfs_io_ctl *io_ctl, + struct btrfs_free_space_ctl *ctl, + struct btrfs_block_group *block_group, + int *entries, int *bitmaps, + struct list_head *bitmap_list) +{ + int ret; + struct btrfs_free_cluster *cluster = NULL; + struct btrfs_free_cluster *cluster_locked = NULL; + struct rb_node *node = rb_first(&ctl->free_space_offset); + struct btrfs_trim_range *trim_entry; + + /* Get the cluster for this block_group if it exists */ + if (block_group && !list_empty(&block_group->cluster_list)) { + cluster = list_entry(block_group->cluster_list.next, + struct btrfs_free_cluster, + block_group_list); + } + + if (!node && cluster) { + cluster_locked = cluster; + spin_lock(&cluster_locked->lock); + node = rb_first(&cluster->root); + cluster = NULL; + } + + /* Write out the extent entries */ + while (node) { + struct btrfs_free_space *e; + + e = rb_entry(node, struct btrfs_free_space, offset_index); + *entries += 1; + + ret = io_ctl_add_entry(io_ctl, e->offset, e->bytes, + e->bitmap); + if (ret) + goto fail; + + if (e->bitmap) { + list_add_tail(&e->list, bitmap_list); + *bitmaps += 1; + } + node = rb_next(node); + if (!node && cluster) { + node = rb_first(&cluster->root); + cluster_locked = cluster; + spin_lock(&cluster_locked->lock); + cluster = NULL; + } + } + if (cluster_locked) { + spin_unlock(&cluster_locked->lock); + cluster_locked = NULL; + } + + /* + * Make sure we don't miss any range that was removed from our rbtree + * because trimming is running. Otherwise after a umount+mount (or crash + * after committing the transaction) we would leak free space and get + * an inconsistent free space cache report from fsck. + */ + list_for_each_entry(trim_entry, &ctl->trimming_ranges, list) { + ret = io_ctl_add_entry(io_ctl, trim_entry->start, + trim_entry->bytes, NULL); + if (ret) + goto fail; + *entries += 1; + } + + return 0; +fail: + if (cluster_locked) + spin_unlock(&cluster_locked->lock); + return -ENOSPC; +} + +static noinline_for_stack int +update_cache_item(struct btrfs_trans_handle *trans, + struct btrfs_root *root, + struct inode *inode, + struct btrfs_path *path, u64 offset, + int entries, int bitmaps) +{ + struct btrfs_key key; + struct btrfs_free_space_header *header; + struct extent_buffer *leaf; + int ret; + + key.objectid = BTRFS_FREE_SPACE_OBJECTID; + key.offset = offset; + key.type = 0; + + ret = btrfs_search_slot(trans, root, &key, path, 0, 1); + if (ret < 0) { + clear_extent_bit(&BTRFS_I(inode)->io_tree, 0, inode->i_size - 1, + EXTENT_DELALLOC, NULL); + goto fail; + } + leaf = path->nodes[0]; + if (ret > 0) { + struct btrfs_key found_key; + ASSERT(path->slots[0]); + path->slots[0]--; + btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]); + if (found_key.objectid != BTRFS_FREE_SPACE_OBJECTID || + found_key.offset != offset) { + clear_extent_bit(&BTRFS_I(inode)->io_tree, 0, + inode->i_size - 1, EXTENT_DELALLOC, + NULL); + btrfs_release_path(path); + goto fail; + } + } + + BTRFS_I(inode)->generation = trans->transid; + header = btrfs_item_ptr(leaf, path->slots[0], + struct btrfs_free_space_header); + btrfs_set_free_space_entries(leaf, header, entries); + btrfs_set_free_space_bitmaps(leaf, header, bitmaps); + btrfs_set_free_space_generation(leaf, header, trans->transid); + btrfs_mark_buffer_dirty(trans, leaf); + btrfs_release_path(path); + + return 0; + +fail: + return -1; +} + +static noinline_for_stack int write_pinned_extent_entries( + struct btrfs_trans_handle *trans, + struct btrfs_block_group *block_group, + struct btrfs_io_ctl *io_ctl, + int *entries) +{ + u64 start, extent_start, extent_end, len; + struct extent_io_tree *unpin = NULL; + int ret; + + if (!block_group) + return 0; + + /* + * We want to add any pinned extents to our free space cache + * so we don't leak the space + * + * We shouldn't have switched the pinned extents yet so this is the + * right one + */ + unpin = &trans->transaction->pinned_extents; + + start = block_group->start; + + while (start < block_group->start + block_group->length) { + if (!find_first_extent_bit(unpin, start, + &extent_start, &extent_end, + EXTENT_DIRTY, NULL)) + return 0; + + /* This pinned extent is out of our range */ + if (extent_start >= block_group->start + block_group->length) + return 0; + + extent_start = max(extent_start, start); + extent_end = min(block_group->start + block_group->length, + extent_end + 1); + len = extent_end - extent_start; + + *entries += 1; + ret = io_ctl_add_entry(io_ctl, extent_start, len, NULL); + if (ret) + return -ENOSPC; + + start = extent_end; + } + + return 0; +} + +static noinline_for_stack int +write_bitmap_entries(struct btrfs_io_ctl *io_ctl, struct list_head *bitmap_list) +{ + struct btrfs_free_space *entry, *next; + int ret; + + /* Write out the bitmaps */ + list_for_each_entry_safe(entry, next, bitmap_list, list) { + ret = io_ctl_add_bitmap(io_ctl, entry->bitmap); + if (ret) + return -ENOSPC; + list_del_init(&entry->list); + } + + return 0; +} + +static int flush_dirty_cache(struct inode *inode) +{ + int ret; + + ret = btrfs_wait_ordered_range(inode, 0, (u64)-1); + if (ret) + clear_extent_bit(&BTRFS_I(inode)->io_tree, 0, inode->i_size - 1, + EXTENT_DELALLOC, NULL); + + return ret; +} + +static void noinline_for_stack +cleanup_bitmap_list(struct list_head *bitmap_list) +{ + struct btrfs_free_space *entry, *next; + + list_for_each_entry_safe(entry, next, bitmap_list, list) + list_del_init(&entry->list); +} + +static void noinline_for_stack +cleanup_write_cache_enospc(struct inode *inode, + struct btrfs_io_ctl *io_ctl, + struct extent_state **cached_state) +{ + io_ctl_drop_pages(io_ctl); + unlock_extent(&BTRFS_I(inode)->io_tree, 0, i_size_read(inode) - 1, + cached_state); +} + +static int __btrfs_wait_cache_io(struct btrfs_root *root, + struct btrfs_trans_handle *trans, + struct btrfs_block_group *block_group, + struct btrfs_io_ctl *io_ctl, + struct btrfs_path *path, u64 offset) +{ + int ret; + struct inode *inode = io_ctl->inode; + + if (!inode) + return 0; + + /* Flush the dirty pages in the cache file. */ + ret = flush_dirty_cache(inode); + if (ret) + goto out; + + /* Update the cache item to tell everyone this cache file is valid. */ + ret = update_cache_item(trans, root, inode, path, offset, + io_ctl->entries, io_ctl->bitmaps); +out: + if (ret) { + invalidate_inode_pages2(inode->i_mapping); + BTRFS_I(inode)->generation = 0; + if (block_group) + btrfs_debug(root->fs_info, + "failed to write free space cache for block group %llu error %d", + block_group->start, ret); + } + btrfs_update_inode(trans, root, BTRFS_I(inode)); + + if (block_group) { + /* the dirty list is protected by the dirty_bgs_lock */ + spin_lock(&trans->transaction->dirty_bgs_lock); + + /* the disk_cache_state is protected by the block group lock */ + spin_lock(&block_group->lock); + + /* + * only mark this as written if we didn't get put back on + * the dirty list while waiting for IO. Otherwise our + * cache state won't be right, and we won't get written again + */ + if (!ret && list_empty(&block_group->dirty_list)) + block_group->disk_cache_state = BTRFS_DC_WRITTEN; + else if (ret) + block_group->disk_cache_state = BTRFS_DC_ERROR; + + spin_unlock(&block_group->lock); + spin_unlock(&trans->transaction->dirty_bgs_lock); + io_ctl->inode = NULL; + iput(inode); + } + + return ret; + +} + +int btrfs_wait_cache_io(struct btrfs_trans_handle *trans, + struct btrfs_block_group *block_group, + struct btrfs_path *path) +{ + return __btrfs_wait_cache_io(block_group->fs_info->tree_root, trans, + block_group, &block_group->io_ctl, + path, block_group->start); +} + +/* + * Write out cached info to an inode. + * + * @root: root the inode belongs to + * @inode: freespace inode we are writing out + * @ctl: free space cache we are going to write out + * @block_group: block_group for this cache if it belongs to a block_group + * @io_ctl: holds context for the io + * @trans: the trans handle + * + * This function writes out a free space cache struct to disk for quick recovery + * on mount. This will return 0 if it was successful in writing the cache out, + * or an errno if it was not. + */ +static int __btrfs_write_out_cache(struct btrfs_root *root, struct inode *inode, + struct btrfs_free_space_ctl *ctl, + struct btrfs_block_group *block_group, + struct btrfs_io_ctl *io_ctl, + struct btrfs_trans_handle *trans) +{ + struct extent_state *cached_state = NULL; + LIST_HEAD(bitmap_list); + int entries = 0; + int bitmaps = 0; + int ret; + int must_iput = 0; + + if (!i_size_read(inode)) + return -EIO; + + WARN_ON(io_ctl->pages); + ret = io_ctl_init(io_ctl, inode, 1); + if (ret) + return ret; + + if (block_group && (block_group->flags & BTRFS_BLOCK_GROUP_DATA)) { + down_write(&block_group->data_rwsem); + spin_lock(&block_group->lock); + if (block_group->delalloc_bytes) { + block_group->disk_cache_state = BTRFS_DC_WRITTEN; + spin_unlock(&block_group->lock); + up_write(&block_group->data_rwsem); + BTRFS_I(inode)->generation = 0; + ret = 0; + must_iput = 1; + goto out; + } + spin_unlock(&block_group->lock); + } + + /* Lock all pages first so we can lock the extent safely. */ + ret = io_ctl_prepare_pages(io_ctl, false); + if (ret) + goto out_unlock; + + lock_extent(&BTRFS_I(inode)->io_tree, 0, i_size_read(inode) - 1, + &cached_state); + + io_ctl_set_generation(io_ctl, trans->transid); + + mutex_lock(&ctl->cache_writeout_mutex); + /* Write out the extent entries in the free space cache */ + spin_lock(&ctl->tree_lock); + ret = write_cache_extent_entries(io_ctl, ctl, + block_group, &entries, &bitmaps, + &bitmap_list); + if (ret) + goto out_nospc_locked; + + /* + * Some spaces that are freed in the current transaction are pinned, + * they will be added into free space cache after the transaction is + * committed, we shouldn't lose them. + * + * If this changes while we are working we'll get added back to + * the dirty list and redo it. No locking needed + */ + ret = write_pinned_extent_entries(trans, block_group, io_ctl, &entries); + if (ret) + goto out_nospc_locked; + + /* + * At last, we write out all the bitmaps and keep cache_writeout_mutex + * locked while doing it because a concurrent trim can be manipulating + * or freeing the bitmap. + */ + ret = write_bitmap_entries(io_ctl, &bitmap_list); + spin_unlock(&ctl->tree_lock); + mutex_unlock(&ctl->cache_writeout_mutex); + if (ret) + goto out_nospc; + + /* Zero out the rest of the pages just to make sure */ + io_ctl_zero_remaining_pages(io_ctl); + + /* Everything is written out, now we dirty the pages in the file. */ + ret = btrfs_dirty_pages(BTRFS_I(inode), io_ctl->pages, + io_ctl->num_pages, 0, i_size_read(inode), + &cached_state, false); + if (ret) + goto out_nospc; + + if (block_group && (block_group->flags & BTRFS_BLOCK_GROUP_DATA)) + up_write(&block_group->data_rwsem); + /* + * Release the pages and unlock the extent, we will flush + * them out later + */ + io_ctl_drop_pages(io_ctl); + io_ctl_free(io_ctl); + + unlock_extent(&BTRFS_I(inode)->io_tree, 0, i_size_read(inode) - 1, + &cached_state); + + /* + * at this point the pages are under IO and we're happy, + * The caller is responsible for waiting on them and updating + * the cache and the inode + */ + io_ctl->entries = entries; + io_ctl->bitmaps = bitmaps; + + ret = btrfs_fdatawrite_range(inode, 0, (u64)-1); + if (ret) + goto out; + + return 0; + +out_nospc_locked: + cleanup_bitmap_list(&bitmap_list); + spin_unlock(&ctl->tree_lock); + mutex_unlock(&ctl->cache_writeout_mutex); + +out_nospc: + cleanup_write_cache_enospc(inode, io_ctl, &cached_state); + +out_unlock: + if (block_group && (block_group->flags & BTRFS_BLOCK_GROUP_DATA)) + up_write(&block_group->data_rwsem); + +out: + io_ctl->inode = NULL; + io_ctl_free(io_ctl); + if (ret) { + invalidate_inode_pages2(inode->i_mapping); + BTRFS_I(inode)->generation = 0; + } + btrfs_update_inode(trans, root, BTRFS_I(inode)); + if (must_iput) + iput(inode); + return ret; +} + +int btrfs_write_out_cache(struct btrfs_trans_handle *trans, + struct btrfs_block_group *block_group, + struct btrfs_path *path) +{ + struct btrfs_fs_info *fs_info = trans->fs_info; + struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl; + struct inode *inode; + int ret = 0; + + spin_lock(&block_group->lock); + if (block_group->disk_cache_state < BTRFS_DC_SETUP) { + spin_unlock(&block_group->lock); + return 0; + } + spin_unlock(&block_group->lock); + + inode = lookup_free_space_inode(block_group, path); + if (IS_ERR(inode)) + return 0; + + ret = __btrfs_write_out_cache(fs_info->tree_root, inode, ctl, + block_group, &block_group->io_ctl, trans); + if (ret) { + btrfs_debug(fs_info, + "failed to write free space cache for block group %llu error %d", + block_group->start, ret); + spin_lock(&block_group->lock); + block_group->disk_cache_state = BTRFS_DC_ERROR; + spin_unlock(&block_group->lock); + + block_group->io_ctl.inode = NULL; + iput(inode); + } + + /* + * if ret == 0 the caller is expected to call btrfs_wait_cache_io + * to wait for IO and put the inode + */ + + return ret; +} + +static inline unsigned long offset_to_bit(u64 bitmap_start, u32 unit, + u64 offset) +{ + ASSERT(offset >= bitmap_start); + offset -= bitmap_start; + return (unsigned long)(div_u64(offset, unit)); +} + +static inline unsigned long bytes_to_bits(u64 bytes, u32 unit) +{ + return (unsigned long)(div_u64(bytes, unit)); +} + +static inline u64 offset_to_bitmap(struct btrfs_free_space_ctl *ctl, + u64 offset) +{ + u64 bitmap_start; + u64 bytes_per_bitmap; + + bytes_per_bitmap = BITS_PER_BITMAP * ctl->unit; + bitmap_start = offset - ctl->start; + bitmap_start = div64_u64(bitmap_start, bytes_per_bitmap); + bitmap_start *= bytes_per_bitmap; + bitmap_start += ctl->start; + + return bitmap_start; +} + +static int tree_insert_offset(struct btrfs_free_space_ctl *ctl, + struct btrfs_free_cluster *cluster, + struct btrfs_free_space *new_entry) +{ + struct rb_root *root; + struct rb_node **p; + struct rb_node *parent = NULL; + + lockdep_assert_held(&ctl->tree_lock); + + if (cluster) { + lockdep_assert_held(&cluster->lock); + root = &cluster->root; + } else { + root = &ctl->free_space_offset; + } + + p = &root->rb_node; + + while (*p) { + struct btrfs_free_space *info; + + parent = *p; + info = rb_entry(parent, struct btrfs_free_space, offset_index); + + if (new_entry->offset < info->offset) { + p = &(*p)->rb_left; + } else if (new_entry->offset > info->offset) { + p = &(*p)->rb_right; + } else { + /* + * we could have a bitmap entry and an extent entry + * share the same offset. If this is the case, we want + * the extent entry to always be found first if we do a + * linear search through the tree, since we want to have + * the quickest allocation time, and allocating from an + * extent is faster than allocating from a bitmap. So + * if we're inserting a bitmap and we find an entry at + * this offset, we want to go right, or after this entry + * logically. If we are inserting an extent and we've + * found a bitmap, we want to go left, or before + * logically. + */ + if (new_entry->bitmap) { + if (info->bitmap) { + WARN_ON_ONCE(1); + return -EEXIST; + } + p = &(*p)->rb_right; + } else { + if (!info->bitmap) { + WARN_ON_ONCE(1); + return -EEXIST; + } + p = &(*p)->rb_left; + } + } + } + + rb_link_node(&new_entry->offset_index, parent, p); + rb_insert_color(&new_entry->offset_index, root); + + return 0; +} + +/* + * This is a little subtle. We *only* have ->max_extent_size set if we actually + * searched through the bitmap and figured out the largest ->max_extent_size, + * otherwise it's 0. In the case that it's 0 we don't want to tell the + * allocator the wrong thing, we want to use the actual real max_extent_size + * we've found already if it's larger, or we want to use ->bytes. + * + * This matters because find_free_space() will skip entries who's ->bytes is + * less than the required bytes. So if we didn't search down this bitmap, we + * may pick some previous entry that has a smaller ->max_extent_size than we + * have. For example, assume we have two entries, one that has + * ->max_extent_size set to 4K and ->bytes set to 1M. A second entry hasn't set + * ->max_extent_size yet, has ->bytes set to 8K and it's contiguous. We will + * call into find_free_space(), and return with max_extent_size == 4K, because + * that first bitmap entry had ->max_extent_size set, but the second one did + * not. If instead we returned 8K we'd come in searching for 8K, and find the + * 8K contiguous range. + * + * Consider the other case, we have 2 8K chunks in that second entry and still + * don't have ->max_extent_size set. We'll return 16K, and the next time the + * allocator comes in it'll fully search our second bitmap, and this time it'll + * get an uptodate value of 8K as the maximum chunk size. Then we'll get the + * right allocation the next loop through. + */ +static inline u64 get_max_extent_size(const struct btrfs_free_space *entry) +{ + if (entry->bitmap && entry->max_extent_size) + return entry->max_extent_size; + return entry->bytes; +} + +/* + * We want the largest entry to be leftmost, so this is inverted from what you'd + * normally expect. + */ +static bool entry_less(struct rb_node *node, const struct rb_node *parent) +{ + const struct btrfs_free_space *entry, *exist; + + entry = rb_entry(node, struct btrfs_free_space, bytes_index); + exist = rb_entry(parent, struct btrfs_free_space, bytes_index); + return get_max_extent_size(exist) < get_max_extent_size(entry); +} + +/* + * searches the tree for the given offset. + * + * fuzzy - If this is set, then we are trying to make an allocation, and we just + * want a section that has at least bytes size and comes at or after the given + * offset. + */ +static struct btrfs_free_space * +tree_search_offset(struct btrfs_free_space_ctl *ctl, + u64 offset, int bitmap_only, int fuzzy) +{ + struct rb_node *n = ctl->free_space_offset.rb_node; + struct btrfs_free_space *entry = NULL, *prev = NULL; + + lockdep_assert_held(&ctl->tree_lock); + + /* find entry that is closest to the 'offset' */ + while (n) { + entry = rb_entry(n, struct btrfs_free_space, offset_index); + prev = entry; + + if (offset < entry->offset) + n = n->rb_left; + else if (offset > entry->offset) + n = n->rb_right; + else + break; + + entry = NULL; + } + + if (bitmap_only) { + if (!entry) + return NULL; + if (entry->bitmap) + return entry; + + /* + * bitmap entry and extent entry may share same offset, + * in that case, bitmap entry comes after extent entry. + */ + n = rb_next(n); + if (!n) + return NULL; + entry = rb_entry(n, struct btrfs_free_space, offset_index); + if (entry->offset != offset) + return NULL; + + WARN_ON(!entry->bitmap); + return entry; + } else if (entry) { + if (entry->bitmap) { + /* + * if previous extent entry covers the offset, + * we should return it instead of the bitmap entry + */ + n = rb_prev(&entry->offset_index); + if (n) { + prev = rb_entry(n, struct btrfs_free_space, + offset_index); + if (!prev->bitmap && + prev->offset + prev->bytes > offset) + entry = prev; + } + } + return entry; + } + + if (!prev) + return NULL; + + /* find last entry before the 'offset' */ + entry = prev; + if (entry->offset > offset) { + n = rb_prev(&entry->offset_index); + if (n) { + entry = rb_entry(n, struct btrfs_free_space, + offset_index); + ASSERT(entry->offset <= offset); + } else { + if (fuzzy) + return entry; + else + return NULL; + } + } + + if (entry->bitmap) { + n = rb_prev(&entry->offset_index); + if (n) { + prev = rb_entry(n, struct btrfs_free_space, + offset_index); + if (!prev->bitmap && + prev->offset + prev->bytes > offset) + return prev; + } + if (entry->offset + BITS_PER_BITMAP * ctl->unit > offset) + return entry; + } else if (entry->offset + entry->bytes > offset) + return entry; + + if (!fuzzy) + return NULL; + + while (1) { + n = rb_next(&entry->offset_index); + if (!n) + return NULL; + entry = rb_entry(n, struct btrfs_free_space, offset_index); + if (entry->bitmap) { + if (entry->offset + BITS_PER_BITMAP * + ctl->unit > offset) + break; + } else { + if (entry->offset + entry->bytes > offset) + break; + } + } + return entry; +} + +static inline void unlink_free_space(struct btrfs_free_space_ctl *ctl, + struct btrfs_free_space *info, + bool update_stat) +{ + lockdep_assert_held(&ctl->tree_lock); + + rb_erase(&info->offset_index, &ctl->free_space_offset); + rb_erase_cached(&info->bytes_index, &ctl->free_space_bytes); + ctl->free_extents--; + + if (!info->bitmap && !btrfs_free_space_trimmed(info)) { + ctl->discardable_extents[BTRFS_STAT_CURR]--; + ctl->discardable_bytes[BTRFS_STAT_CURR] -= info->bytes; + } + + if (update_stat) + ctl->free_space -= info->bytes; +} + +static int link_free_space(struct btrfs_free_space_ctl *ctl, + struct btrfs_free_space *info) +{ + int ret = 0; + + lockdep_assert_held(&ctl->tree_lock); + + ASSERT(info->bytes || info->bitmap); + ret = tree_insert_offset(ctl, NULL, info); + if (ret) + return ret; + + rb_add_cached(&info->bytes_index, &ctl->free_space_bytes, entry_less); + + if (!info->bitmap && !btrfs_free_space_trimmed(info)) { + ctl->discardable_extents[BTRFS_STAT_CURR]++; + ctl->discardable_bytes[BTRFS_STAT_CURR] += info->bytes; + } + + ctl->free_space += info->bytes; + ctl->free_extents++; + return ret; +} + +static void relink_bitmap_entry(struct btrfs_free_space_ctl *ctl, + struct btrfs_free_space *info) +{ + ASSERT(info->bitmap); + + /* + * If our entry is empty it's because we're on a cluster and we don't + * want to re-link it into our ctl bytes index. + */ + if (RB_EMPTY_NODE(&info->bytes_index)) + return; + + lockdep_assert_held(&ctl->tree_lock); + + rb_erase_cached(&info->bytes_index, &ctl->free_space_bytes); + rb_add_cached(&info->bytes_index, &ctl->free_space_bytes, entry_less); +} + +static inline void bitmap_clear_bits(struct btrfs_free_space_ctl *ctl, + struct btrfs_free_space *info, + u64 offset, u64 bytes, bool update_stat) +{ + unsigned long start, count, end; + int extent_delta = -1; + + start = offset_to_bit(info->offset, ctl->unit, offset); + count = bytes_to_bits(bytes, ctl->unit); + end = start + count; + ASSERT(end <= BITS_PER_BITMAP); + + bitmap_clear(info->bitmap, start, count); + + info->bytes -= bytes; + if (info->max_extent_size > ctl->unit) + info->max_extent_size = 0; + + relink_bitmap_entry(ctl, info); + + if (start && test_bit(start - 1, info->bitmap)) + extent_delta++; + + if (end < BITS_PER_BITMAP && test_bit(end, info->bitmap)) + extent_delta++; + + info->bitmap_extents += extent_delta; + if (!btrfs_free_space_trimmed(info)) { + ctl->discardable_extents[BTRFS_STAT_CURR] += extent_delta; + ctl->discardable_bytes[BTRFS_STAT_CURR] -= bytes; + } + + if (update_stat) + ctl->free_space -= bytes; +} + +static void bitmap_set_bits(struct btrfs_free_space_ctl *ctl, + struct btrfs_free_space *info, u64 offset, + u64 bytes) +{ + unsigned long start, count, end; + int extent_delta = 1; + + start = offset_to_bit(info->offset, ctl->unit, offset); + count = bytes_to_bits(bytes, ctl->unit); + end = start + count; + ASSERT(end <= BITS_PER_BITMAP); + + bitmap_set(info->bitmap, start, count); + + /* + * We set some bytes, we have no idea what the max extent size is + * anymore. + */ + info->max_extent_size = 0; + info->bytes += bytes; + ctl->free_space += bytes; + + relink_bitmap_entry(ctl, info); + + if (start && test_bit(start - 1, info->bitmap)) + extent_delta--; + + if (end < BITS_PER_BITMAP && test_bit(end, info->bitmap)) + extent_delta--; + + info->bitmap_extents += extent_delta; + if (!btrfs_free_space_trimmed(info)) { + ctl->discardable_extents[BTRFS_STAT_CURR] += extent_delta; + ctl->discardable_bytes[BTRFS_STAT_CURR] += bytes; + } +} + +/* + * If we can not find suitable extent, we will use bytes to record + * the size of the max extent. + */ +static int search_bitmap(struct btrfs_free_space_ctl *ctl, + struct btrfs_free_space *bitmap_info, u64 *offset, + u64 *bytes, bool for_alloc) +{ + unsigned long found_bits = 0; + unsigned long max_bits = 0; + unsigned long bits, i; + unsigned long next_zero; + unsigned long extent_bits; + + /* + * Skip searching the bitmap if we don't have a contiguous section that + * is large enough for this allocation. + */ + if (for_alloc && + bitmap_info->max_extent_size && + bitmap_info->max_extent_size < *bytes) { + *bytes = bitmap_info->max_extent_size; + return -1; + } + + i = offset_to_bit(bitmap_info->offset, ctl->unit, + max_t(u64, *offset, bitmap_info->offset)); + bits = bytes_to_bits(*bytes, ctl->unit); + + for_each_set_bit_from(i, bitmap_info->bitmap, BITS_PER_BITMAP) { + if (for_alloc && bits == 1) { + found_bits = 1; + break; + } + next_zero = find_next_zero_bit(bitmap_info->bitmap, + BITS_PER_BITMAP, i); + extent_bits = next_zero - i; + if (extent_bits >= bits) { + found_bits = extent_bits; + break; + } else if (extent_bits > max_bits) { + max_bits = extent_bits; + } + i = next_zero; + } + + if (found_bits) { + *offset = (u64)(i * ctl->unit) + bitmap_info->offset; + *bytes = (u64)(found_bits) * ctl->unit; + return 0; + } + + *bytes = (u64)(max_bits) * ctl->unit; + bitmap_info->max_extent_size = *bytes; + relink_bitmap_entry(ctl, bitmap_info); + return -1; +} + +/* Cache the size of the max extent in bytes */ +static struct btrfs_free_space * +find_free_space(struct btrfs_free_space_ctl *ctl, u64 *offset, u64 *bytes, + unsigned long align, u64 *max_extent_size, bool use_bytes_index) +{ + struct btrfs_free_space *entry; + struct rb_node *node; + u64 tmp; + u64 align_off; + int ret; + + if (!ctl->free_space_offset.rb_node) + goto out; +again: + if (use_bytes_index) { + node = rb_first_cached(&ctl->free_space_bytes); + } else { + entry = tree_search_offset(ctl, offset_to_bitmap(ctl, *offset), + 0, 1); + if (!entry) + goto out; + node = &entry->offset_index; + } + + for (; node; node = rb_next(node)) { + if (use_bytes_index) + entry = rb_entry(node, struct btrfs_free_space, + bytes_index); + else + entry = rb_entry(node, struct btrfs_free_space, + offset_index); + + /* + * If we are using the bytes index then all subsequent entries + * in this tree are going to be < bytes, so simply set the max + * extent size and exit the loop. + * + * If we're using the offset index then we need to keep going + * through the rest of the tree. + */ + if (entry->bytes < *bytes) { + *max_extent_size = max(get_max_extent_size(entry), + *max_extent_size); + if (use_bytes_index) + break; + continue; + } + + /* make sure the space returned is big enough + * to match our requested alignment + */ + if (*bytes >= align) { + tmp = entry->offset - ctl->start + align - 1; + tmp = div64_u64(tmp, align); + tmp = tmp * align + ctl->start; + align_off = tmp - entry->offset; + } else { + align_off = 0; + tmp = entry->offset; + } + + /* + * We don't break here if we're using the bytes index because we + * may have another entry that has the correct alignment that is + * the right size, so we don't want to miss that possibility. + * At worst this adds another loop through the logic, but if we + * broke here we could prematurely ENOSPC. + */ + if (entry->bytes < *bytes + align_off) { + *max_extent_size = max(get_max_extent_size(entry), + *max_extent_size); + continue; + } + + if (entry->bitmap) { + struct rb_node *old_next = rb_next(node); + u64 size = *bytes; + + ret = search_bitmap(ctl, entry, &tmp, &size, true); + if (!ret) { + *offset = tmp; + *bytes = size; + return entry; + } else { + *max_extent_size = + max(get_max_extent_size(entry), + *max_extent_size); + } + + /* + * The bitmap may have gotten re-arranged in the space + * index here because the max_extent_size may have been + * updated. Start from the beginning again if this + * happened. + */ + if (use_bytes_index && old_next != rb_next(node)) + goto again; + continue; + } + + *offset = tmp; + *bytes = entry->bytes - align_off; + return entry; + } +out: + return NULL; +} + +static void add_new_bitmap(struct btrfs_free_space_ctl *ctl, + struct btrfs_free_space *info, u64 offset) +{ + info->offset = offset_to_bitmap(ctl, offset); + info->bytes = 0; + info->bitmap_extents = 0; + INIT_LIST_HEAD(&info->list); + link_free_space(ctl, info); + ctl->total_bitmaps++; + recalculate_thresholds(ctl); +} + +static void free_bitmap(struct btrfs_free_space_ctl *ctl, + struct btrfs_free_space *bitmap_info) +{ + /* + * Normally when this is called, the bitmap is completely empty. However, + * if we are blowing up the free space cache for one reason or another + * via __btrfs_remove_free_space_cache(), then it may not be freed and + * we may leave stats on the table. + */ + if (bitmap_info->bytes && !btrfs_free_space_trimmed(bitmap_info)) { + ctl->discardable_extents[BTRFS_STAT_CURR] -= + bitmap_info->bitmap_extents; + ctl->discardable_bytes[BTRFS_STAT_CURR] -= bitmap_info->bytes; + + } + unlink_free_space(ctl, bitmap_info, true); + kmem_cache_free(btrfs_free_space_bitmap_cachep, bitmap_info->bitmap); + kmem_cache_free(btrfs_free_space_cachep, bitmap_info); + ctl->total_bitmaps--; + recalculate_thresholds(ctl); +} + +static noinline int remove_from_bitmap(struct btrfs_free_space_ctl *ctl, + struct btrfs_free_space *bitmap_info, + u64 *offset, u64 *bytes) +{ + u64 end; + u64 search_start, search_bytes; + int ret; + +again: + end = bitmap_info->offset + (u64)(BITS_PER_BITMAP * ctl->unit) - 1; + + /* + * We need to search for bits in this bitmap. We could only cover some + * of the extent in this bitmap thanks to how we add space, so we need + * to search for as much as it as we can and clear that amount, and then + * go searching for the next bit. + */ + search_start = *offset; + search_bytes = ctl->unit; + search_bytes = min(search_bytes, end - search_start + 1); + ret = search_bitmap(ctl, bitmap_info, &search_start, &search_bytes, + false); + if (ret < 0 || search_start != *offset) + return -EINVAL; + + /* We may have found more bits than what we need */ + search_bytes = min(search_bytes, *bytes); + + /* Cannot clear past the end of the bitmap */ + search_bytes = min(search_bytes, end - search_start + 1); + + bitmap_clear_bits(ctl, bitmap_info, search_start, search_bytes, true); + *offset += search_bytes; + *bytes -= search_bytes; + + if (*bytes) { + struct rb_node *next = rb_next(&bitmap_info->offset_index); + if (!bitmap_info->bytes) + free_bitmap(ctl, bitmap_info); + + /* + * no entry after this bitmap, but we still have bytes to + * remove, so something has gone wrong. + */ + if (!next) + return -EINVAL; + + bitmap_info = rb_entry(next, struct btrfs_free_space, + offset_index); + + /* + * if the next entry isn't a bitmap we need to return to let the + * extent stuff do its work. + */ + if (!bitmap_info->bitmap) + return -EAGAIN; + + /* + * Ok the next item is a bitmap, but it may not actually hold + * the information for the rest of this free space stuff, so + * look for it, and if we don't find it return so we can try + * everything over again. + */ + search_start = *offset; + search_bytes = ctl->unit; + ret = search_bitmap(ctl, bitmap_info, &search_start, + &search_bytes, false); + if (ret < 0 || search_start != *offset) + return -EAGAIN; + + goto again; + } else if (!bitmap_info->bytes) + free_bitmap(ctl, bitmap_info); + + return 0; +} + +static u64 add_bytes_to_bitmap(struct btrfs_free_space_ctl *ctl, + struct btrfs_free_space *info, u64 offset, + u64 bytes, enum btrfs_trim_state trim_state) +{ + u64 bytes_to_set = 0; + u64 end; + + /* + * This is a tradeoff to make bitmap trim state minimal. We mark the + * whole bitmap untrimmed if at any point we add untrimmed regions. + */ + if (trim_state == BTRFS_TRIM_STATE_UNTRIMMED) { + if (btrfs_free_space_trimmed(info)) { + ctl->discardable_extents[BTRFS_STAT_CURR] += + info->bitmap_extents; + ctl->discardable_bytes[BTRFS_STAT_CURR] += info->bytes; + } + info->trim_state = BTRFS_TRIM_STATE_UNTRIMMED; + } + + end = info->offset + (u64)(BITS_PER_BITMAP * ctl->unit); + + bytes_to_set = min(end - offset, bytes); + + bitmap_set_bits(ctl, info, offset, bytes_to_set); + + return bytes_to_set; + +} + +static bool use_bitmap(struct btrfs_free_space_ctl *ctl, + struct btrfs_free_space *info) +{ + struct btrfs_block_group *block_group = ctl->block_group; + struct btrfs_fs_info *fs_info = block_group->fs_info; + bool forced = false; + +#ifdef CONFIG_BTRFS_DEBUG + if (btrfs_should_fragment_free_space(block_group)) + forced = true; +#endif + + /* This is a way to reclaim large regions from the bitmaps. */ + if (!forced && info->bytes >= FORCE_EXTENT_THRESHOLD) + return false; + + /* + * If we are below the extents threshold then we can add this as an + * extent, and don't have to deal with the bitmap + */ + if (!forced && ctl->free_extents < ctl->extents_thresh) { + /* + * If this block group has some small extents we don't want to + * use up all of our free slots in the cache with them, we want + * to reserve them to larger extents, however if we have plenty + * of cache left then go ahead an dadd them, no sense in adding + * the overhead of a bitmap if we don't have to. + */ + if (info->bytes <= fs_info->sectorsize * 8) { + if (ctl->free_extents * 3 <= ctl->extents_thresh) + return false; + } else { + return false; + } + } + + /* + * The original block groups from mkfs can be really small, like 8 + * megabytes, so don't bother with a bitmap for those entries. However + * some block groups can be smaller than what a bitmap would cover but + * are still large enough that they could overflow the 32k memory limit, + * so allow those block groups to still be allowed to have a bitmap + * entry. + */ + if (((BITS_PER_BITMAP * ctl->unit) >> 1) > block_group->length) + return false; + + return true; +} + +static const struct btrfs_free_space_op free_space_op = { + .use_bitmap = use_bitmap, +}; + +static int insert_into_bitmap(struct btrfs_free_space_ctl *ctl, + struct btrfs_free_space *info) +{ + struct btrfs_free_space *bitmap_info; + struct btrfs_block_group *block_group = NULL; + int added = 0; + u64 bytes, offset, bytes_added; + enum btrfs_trim_state trim_state; + int ret; + + bytes = info->bytes; + offset = info->offset; + trim_state = info->trim_state; + + if (!ctl->op->use_bitmap(ctl, info)) + return 0; + + if (ctl->op == &free_space_op) + block_group = ctl->block_group; +again: + /* + * Since we link bitmaps right into the cluster we need to see if we + * have a cluster here, and if so and it has our bitmap we need to add + * the free space to that bitmap. + */ + if (block_group && !list_empty(&block_group->cluster_list)) { + struct btrfs_free_cluster *cluster; + struct rb_node *node; + struct btrfs_free_space *entry; + + cluster = list_entry(block_group->cluster_list.next, + struct btrfs_free_cluster, + block_group_list); + spin_lock(&cluster->lock); + node = rb_first(&cluster->root); + if (!node) { + spin_unlock(&cluster->lock); + goto no_cluster_bitmap; + } + + entry = rb_entry(node, struct btrfs_free_space, offset_index); + if (!entry->bitmap) { + spin_unlock(&cluster->lock); + goto no_cluster_bitmap; + } + + if (entry->offset == offset_to_bitmap(ctl, offset)) { + bytes_added = add_bytes_to_bitmap(ctl, entry, offset, + bytes, trim_state); + bytes -= bytes_added; + offset += bytes_added; + } + spin_unlock(&cluster->lock); + if (!bytes) { + ret = 1; + goto out; + } + } + +no_cluster_bitmap: + bitmap_info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset), + 1, 0); + if (!bitmap_info) { + ASSERT(added == 0); + goto new_bitmap; + } + + bytes_added = add_bytes_to_bitmap(ctl, bitmap_info, offset, bytes, + trim_state); + bytes -= bytes_added; + offset += bytes_added; + added = 0; + + if (!bytes) { + ret = 1; + goto out; + } else + goto again; + +new_bitmap: + if (info && info->bitmap) { + add_new_bitmap(ctl, info, offset); + added = 1; + info = NULL; + goto again; + } else { + spin_unlock(&ctl->tree_lock); + + /* no pre-allocated info, allocate a new one */ + if (!info) { + info = kmem_cache_zalloc(btrfs_free_space_cachep, + GFP_NOFS); + if (!info) { + spin_lock(&ctl->tree_lock); + ret = -ENOMEM; + goto out; + } + } + + /* allocate the bitmap */ + info->bitmap = kmem_cache_zalloc(btrfs_free_space_bitmap_cachep, + GFP_NOFS); + info->trim_state = BTRFS_TRIM_STATE_TRIMMED; + spin_lock(&ctl->tree_lock); + if (!info->bitmap) { + ret = -ENOMEM; + goto out; + } + goto again; + } + +out: + if (info) { + if (info->bitmap) + kmem_cache_free(btrfs_free_space_bitmap_cachep, + info->bitmap); + kmem_cache_free(btrfs_free_space_cachep, info); + } + + return ret; +} + +/* + * Free space merging rules: + * 1) Merge trimmed areas together + * 2) Let untrimmed areas coalesce with trimmed areas + * 3) Always pull neighboring regions from bitmaps + * + * The above rules are for when we merge free space based on btrfs_trim_state. + * Rules 2 and 3 are subtle because they are suboptimal, but are done for the + * same reason: to promote larger extent regions which makes life easier for + * find_free_extent(). Rule 2 enables coalescing based on the common path + * being returning free space from btrfs_finish_extent_commit(). So when free + * space is trimmed, it will prevent aggregating trimmed new region and + * untrimmed regions in the rb_tree. Rule 3 is purely to obtain larger extents + * and provide find_free_extent() with the largest extents possible hoping for + * the reuse path. + */ +static bool try_merge_free_space(struct btrfs_free_space_ctl *ctl, + struct btrfs_free_space *info, bool update_stat) +{ + struct btrfs_free_space *left_info = NULL; + struct btrfs_free_space *right_info; + bool merged = false; + u64 offset = info->offset; + u64 bytes = info->bytes; + const bool is_trimmed = btrfs_free_space_trimmed(info); + struct rb_node *right_prev = NULL; + + /* + * first we want to see if there is free space adjacent to the range we + * are adding, if there is remove that struct and add a new one to + * cover the entire range + */ + right_info = tree_search_offset(ctl, offset + bytes, 0, 0); + if (right_info) + right_prev = rb_prev(&right_info->offset_index); + + if (right_prev) + left_info = rb_entry(right_prev, struct btrfs_free_space, offset_index); + else if (!right_info) + left_info = tree_search_offset(ctl, offset - 1, 0, 0); + + /* See try_merge_free_space() comment. */ + if (right_info && !right_info->bitmap && + (!is_trimmed || btrfs_free_space_trimmed(right_info))) { + unlink_free_space(ctl, right_info, update_stat); + info->bytes += right_info->bytes; + kmem_cache_free(btrfs_free_space_cachep, right_info); + merged = true; + } + + /* See try_merge_free_space() comment. */ + if (left_info && !left_info->bitmap && + left_info->offset + left_info->bytes == offset && + (!is_trimmed || btrfs_free_space_trimmed(left_info))) { + unlink_free_space(ctl, left_info, update_stat); + info->offset = left_info->offset; + info->bytes += left_info->bytes; + kmem_cache_free(btrfs_free_space_cachep, left_info); + merged = true; + } + + return merged; +} + +static bool steal_from_bitmap_to_end(struct btrfs_free_space_ctl *ctl, + struct btrfs_free_space *info, + bool update_stat) +{ + struct btrfs_free_space *bitmap; + unsigned long i; + unsigned long j; + const u64 end = info->offset + info->bytes; + const u64 bitmap_offset = offset_to_bitmap(ctl, end); + u64 bytes; + + bitmap = tree_search_offset(ctl, bitmap_offset, 1, 0); + if (!bitmap) + return false; + + i = offset_to_bit(bitmap->offset, ctl->unit, end); + j = find_next_zero_bit(bitmap->bitmap, BITS_PER_BITMAP, i); + if (j == i) + return false; + bytes = (j - i) * ctl->unit; + info->bytes += bytes; + + /* See try_merge_free_space() comment. */ + if (!btrfs_free_space_trimmed(bitmap)) + info->trim_state = BTRFS_TRIM_STATE_UNTRIMMED; + + bitmap_clear_bits(ctl, bitmap, end, bytes, update_stat); + + if (!bitmap->bytes) + free_bitmap(ctl, bitmap); + + return true; +} + +static bool steal_from_bitmap_to_front(struct btrfs_free_space_ctl *ctl, + struct btrfs_free_space *info, + bool update_stat) +{ + struct btrfs_free_space *bitmap; + u64 bitmap_offset; + unsigned long i; + unsigned long j; + unsigned long prev_j; + u64 bytes; + + bitmap_offset = offset_to_bitmap(ctl, info->offset); + /* If we're on a boundary, try the previous logical bitmap. */ + if (bitmap_offset == info->offset) { + if (info->offset == 0) + return false; + bitmap_offset = offset_to_bitmap(ctl, info->offset - 1); + } + + bitmap = tree_search_offset(ctl, bitmap_offset, 1, 0); + if (!bitmap) + return false; + + i = offset_to_bit(bitmap->offset, ctl->unit, info->offset) - 1; + j = 0; + prev_j = (unsigned long)-1; + for_each_clear_bit_from(j, bitmap->bitmap, BITS_PER_BITMAP) { + if (j > i) + break; + prev_j = j; + } + if (prev_j == i) + return false; + + if (prev_j == (unsigned long)-1) + bytes = (i + 1) * ctl->unit; + else + bytes = (i - prev_j) * ctl->unit; + + info->offset -= bytes; + info->bytes += bytes; + + /* See try_merge_free_space() comment. */ + if (!btrfs_free_space_trimmed(bitmap)) + info->trim_state = BTRFS_TRIM_STATE_UNTRIMMED; + + bitmap_clear_bits(ctl, bitmap, info->offset, bytes, update_stat); + + if (!bitmap->bytes) + free_bitmap(ctl, bitmap); + + return true; +} + +/* + * We prefer always to allocate from extent entries, both for clustered and + * non-clustered allocation requests. So when attempting to add a new extent + * entry, try to see if there's adjacent free space in bitmap entries, and if + * there is, migrate that space from the bitmaps to the extent. + * Like this we get better chances of satisfying space allocation requests + * because we attempt to satisfy them based on a single cache entry, and never + * on 2 or more entries - even if the entries represent a contiguous free space + * region (e.g. 1 extent entry + 1 bitmap entry starting where the extent entry + * ends). + */ +static void steal_from_bitmap(struct btrfs_free_space_ctl *ctl, + struct btrfs_free_space *info, + bool update_stat) +{ + /* + * Only work with disconnected entries, as we can change their offset, + * and must be extent entries. + */ + ASSERT(!info->bitmap); + ASSERT(RB_EMPTY_NODE(&info->offset_index)); + + if (ctl->total_bitmaps > 0) { + bool stole_end; + bool stole_front = false; + + stole_end = steal_from_bitmap_to_end(ctl, info, update_stat); + if (ctl->total_bitmaps > 0) + stole_front = steal_from_bitmap_to_front(ctl, info, + update_stat); + + if (stole_end || stole_front) + try_merge_free_space(ctl, info, update_stat); + } +} + +int __btrfs_add_free_space(struct btrfs_block_group *block_group, + u64 offset, u64 bytes, + enum btrfs_trim_state trim_state) +{ + struct btrfs_fs_info *fs_info = block_group->fs_info; + struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl; + struct btrfs_free_space *info; + int ret = 0; + u64 filter_bytes = bytes; + + ASSERT(!btrfs_is_zoned(fs_info)); + + info = kmem_cache_zalloc(btrfs_free_space_cachep, GFP_NOFS); + if (!info) + return -ENOMEM; + + info->offset = offset; + info->bytes = bytes; + info->trim_state = trim_state; + RB_CLEAR_NODE(&info->offset_index); + RB_CLEAR_NODE(&info->bytes_index); + + spin_lock(&ctl->tree_lock); + + if (try_merge_free_space(ctl, info, true)) + goto link; + + /* + * There was no extent directly to the left or right of this new + * extent then we know we're going to have to allocate a new extent, so + * before we do that see if we need to drop this into a bitmap + */ + ret = insert_into_bitmap(ctl, info); + if (ret < 0) { + goto out; + } else if (ret) { + ret = 0; + goto out; + } +link: + /* + * Only steal free space from adjacent bitmaps if we're sure we're not + * going to add the new free space to existing bitmap entries - because + * that would mean unnecessary work that would be reverted. Therefore + * attempt to steal space from bitmaps if we're adding an extent entry. + */ + steal_from_bitmap(ctl, info, true); + + filter_bytes = max(filter_bytes, info->bytes); + + ret = link_free_space(ctl, info); + if (ret) + kmem_cache_free(btrfs_free_space_cachep, info); +out: + btrfs_discard_update_discardable(block_group); + spin_unlock(&ctl->tree_lock); + + if (ret) { + btrfs_crit(fs_info, "unable to add free space :%d", ret); + ASSERT(ret != -EEXIST); + } + + if (trim_state != BTRFS_TRIM_STATE_TRIMMED) { + btrfs_discard_check_filter(block_group, filter_bytes); + btrfs_discard_queue_work(&fs_info->discard_ctl, block_group); + } + + return ret; +} + +static int __btrfs_add_free_space_zoned(struct btrfs_block_group *block_group, + u64 bytenr, u64 size, bool used) +{ + struct btrfs_space_info *sinfo = block_group->space_info; + struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl; + u64 offset = bytenr - block_group->start; + u64 to_free, to_unusable; + int bg_reclaim_threshold = 0; + bool initial = (size == block_group->length); + u64 reclaimable_unusable; + + WARN_ON(!initial && offset + size > block_group->zone_capacity); + + if (!initial) + bg_reclaim_threshold = READ_ONCE(sinfo->bg_reclaim_threshold); + + spin_lock(&ctl->tree_lock); + if (!used) + to_free = size; + else if (initial) + to_free = block_group->zone_capacity; + else if (offset >= block_group->alloc_offset) + to_free = size; + else if (offset + size <= block_group->alloc_offset) + to_free = 0; + else + to_free = offset + size - block_group->alloc_offset; + to_unusable = size - to_free; + + ctl->free_space += to_free; + /* + * If the block group is read-only, we should account freed space into + * bytes_readonly. + */ + if (!block_group->ro) + block_group->zone_unusable += to_unusable; + spin_unlock(&ctl->tree_lock); + if (!used) { + spin_lock(&block_group->lock); + block_group->alloc_offset -= size; + spin_unlock(&block_group->lock); + } + + reclaimable_unusable = block_group->zone_unusable - + (block_group->length - block_group->zone_capacity); + /* All the region is now unusable. Mark it as unused and reclaim */ + if (block_group->zone_unusable == block_group->length) { + btrfs_mark_bg_unused(block_group); + } else if (bg_reclaim_threshold && + reclaimable_unusable >= + mult_perc(block_group->zone_capacity, bg_reclaim_threshold)) { + btrfs_mark_bg_to_reclaim(block_group); + } + + return 0; +} + +int btrfs_add_free_space(struct btrfs_block_group *block_group, + u64 bytenr, u64 size) +{ + enum btrfs_trim_state trim_state = BTRFS_TRIM_STATE_UNTRIMMED; + + if (btrfs_is_zoned(block_group->fs_info)) + return __btrfs_add_free_space_zoned(block_group, bytenr, size, + true); + + if (btrfs_test_opt(block_group->fs_info, DISCARD_SYNC)) + trim_state = BTRFS_TRIM_STATE_TRIMMED; + + return __btrfs_add_free_space(block_group, bytenr, size, trim_state); +} + +int btrfs_add_free_space_unused(struct btrfs_block_group *block_group, + u64 bytenr, u64 size) +{ + if (btrfs_is_zoned(block_group->fs_info)) + return __btrfs_add_free_space_zoned(block_group, bytenr, size, + false); + + return btrfs_add_free_space(block_group, bytenr, size); +} + +/* + * This is a subtle distinction because when adding free space back in general, + * we want it to be added as untrimmed for async. But in the case where we add + * it on loading of a block group, we want to consider it trimmed. + */ +int btrfs_add_free_space_async_trimmed(struct btrfs_block_group *block_group, + u64 bytenr, u64 size) +{ + enum btrfs_trim_state trim_state = BTRFS_TRIM_STATE_UNTRIMMED; + + if (btrfs_is_zoned(block_group->fs_info)) + return __btrfs_add_free_space_zoned(block_group, bytenr, size, + true); + + if (btrfs_test_opt(block_group->fs_info, DISCARD_SYNC) || + btrfs_test_opt(block_group->fs_info, DISCARD_ASYNC)) + trim_state = BTRFS_TRIM_STATE_TRIMMED; + + return __btrfs_add_free_space(block_group, bytenr, size, trim_state); +} + +int btrfs_remove_free_space(struct btrfs_block_group *block_group, + u64 offset, u64 bytes) +{ + struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl; + struct btrfs_free_space *info; + int ret; + bool re_search = false; + + if (btrfs_is_zoned(block_group->fs_info)) { + /* + * This can happen with conventional zones when replaying log. + * Since the allocation info of tree-log nodes are not recorded + * to the extent-tree, calculate_alloc_pointer() failed to + * advance the allocation pointer after last allocated tree log + * node blocks. + * + * This function is called from + * btrfs_pin_extent_for_log_replay() when replaying the log. + * Advance the pointer not to overwrite the tree-log nodes. + */ + if (block_group->start + block_group->alloc_offset < + offset + bytes) { + block_group->alloc_offset = + offset + bytes - block_group->start; + } + return 0; + } + + spin_lock(&ctl->tree_lock); + +again: + ret = 0; + if (!bytes) + goto out_lock; + + info = tree_search_offset(ctl, offset, 0, 0); + if (!info) { + /* + * oops didn't find an extent that matched the space we wanted + * to remove, look for a bitmap instead + */ + info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset), + 1, 0); + if (!info) { + /* + * If we found a partial bit of our free space in a + * bitmap but then couldn't find the other part this may + * be a problem, so WARN about it. + */ + WARN_ON(re_search); + goto out_lock; + } + } + + re_search = false; + if (!info->bitmap) { + unlink_free_space(ctl, info, true); + if (offset == info->offset) { + u64 to_free = min(bytes, info->bytes); + + info->bytes -= to_free; + info->offset += to_free; + if (info->bytes) { + ret = link_free_space(ctl, info); + WARN_ON(ret); + } else { + kmem_cache_free(btrfs_free_space_cachep, info); + } + + offset += to_free; + bytes -= to_free; + goto again; + } else { + u64 old_end = info->bytes + info->offset; + + info->bytes = offset - info->offset; + ret = link_free_space(ctl, info); + WARN_ON(ret); + if (ret) + goto out_lock; + + /* Not enough bytes in this entry to satisfy us */ + if (old_end < offset + bytes) { + bytes -= old_end - offset; + offset = old_end; + goto again; + } else if (old_end == offset + bytes) { + /* all done */ + goto out_lock; + } + spin_unlock(&ctl->tree_lock); + + ret = __btrfs_add_free_space(block_group, + offset + bytes, + old_end - (offset + bytes), + info->trim_state); + WARN_ON(ret); + goto out; + } + } + + ret = remove_from_bitmap(ctl, info, &offset, &bytes); + if (ret == -EAGAIN) { + re_search = true; + goto again; + } +out_lock: + btrfs_discard_update_discardable(block_group); + spin_unlock(&ctl->tree_lock); +out: + return ret; +} + +void btrfs_dump_free_space(struct btrfs_block_group *block_group, + u64 bytes) +{ + struct btrfs_fs_info *fs_info = block_group->fs_info; + struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl; + struct btrfs_free_space *info; + struct rb_node *n; + int count = 0; + + /* + * Zoned btrfs does not use free space tree and cluster. Just print + * out the free space after the allocation offset. + */ + if (btrfs_is_zoned(fs_info)) { + btrfs_info(fs_info, "free space %llu active %d", + block_group->zone_capacity - block_group->alloc_offset, + test_bit(BLOCK_GROUP_FLAG_ZONE_IS_ACTIVE, + &block_group->runtime_flags)); + return; + } + + spin_lock(&ctl->tree_lock); + for (n = rb_first(&ctl->free_space_offset); n; n = rb_next(n)) { + info = rb_entry(n, struct btrfs_free_space, offset_index); + if (info->bytes >= bytes && !block_group->ro) + count++; + btrfs_crit(fs_info, "entry offset %llu, bytes %llu, bitmap %s", + info->offset, info->bytes, + (info->bitmap) ? "yes" : "no"); + } + spin_unlock(&ctl->tree_lock); + btrfs_info(fs_info, "block group has cluster?: %s", + list_empty(&block_group->cluster_list) ? "no" : "yes"); + btrfs_info(fs_info, + "%d free space entries at or bigger than %llu bytes", + count, bytes); +} + +void btrfs_init_free_space_ctl(struct btrfs_block_group *block_group, + struct btrfs_free_space_ctl *ctl) +{ + struct btrfs_fs_info *fs_info = block_group->fs_info; + + spin_lock_init(&ctl->tree_lock); + ctl->unit = fs_info->sectorsize; + ctl->start = block_group->start; + ctl->block_group = block_group; + ctl->op = &free_space_op; + ctl->free_space_bytes = RB_ROOT_CACHED; + INIT_LIST_HEAD(&ctl->trimming_ranges); + mutex_init(&ctl->cache_writeout_mutex); + + /* + * we only want to have 32k of ram per block group for keeping + * track of free space, and if we pass 1/2 of that we want to + * start converting things over to using bitmaps + */ + ctl->extents_thresh = (SZ_32K / 2) / sizeof(struct btrfs_free_space); +} + +/* + * for a given cluster, put all of its extents back into the free + * space cache. If the block group passed doesn't match the block group + * pointed to by the cluster, someone else raced in and freed the + * cluster already. In that case, we just return without changing anything + */ +static void __btrfs_return_cluster_to_free_space( + struct btrfs_block_group *block_group, + struct btrfs_free_cluster *cluster) +{ + struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl; + struct rb_node *node; + + lockdep_assert_held(&ctl->tree_lock); + + spin_lock(&cluster->lock); + if (cluster->block_group != block_group) { + spin_unlock(&cluster->lock); + return; + } + + cluster->block_group = NULL; + cluster->window_start = 0; + list_del_init(&cluster->block_group_list); + + node = rb_first(&cluster->root); + while (node) { + struct btrfs_free_space *entry; + + entry = rb_entry(node, struct btrfs_free_space, offset_index); + node = rb_next(&entry->offset_index); + rb_erase(&entry->offset_index, &cluster->root); + RB_CLEAR_NODE(&entry->offset_index); + + if (!entry->bitmap) { + /* Merging treats extents as if they were new */ + if (!btrfs_free_space_trimmed(entry)) { + ctl->discardable_extents[BTRFS_STAT_CURR]--; + ctl->discardable_bytes[BTRFS_STAT_CURR] -= + entry->bytes; + } + + try_merge_free_space(ctl, entry, false); + steal_from_bitmap(ctl, entry, false); + + /* As we insert directly, update these statistics */ + if (!btrfs_free_space_trimmed(entry)) { + ctl->discardable_extents[BTRFS_STAT_CURR]++; + ctl->discardable_bytes[BTRFS_STAT_CURR] += + entry->bytes; + } + } + tree_insert_offset(ctl, NULL, entry); + rb_add_cached(&entry->bytes_index, &ctl->free_space_bytes, + entry_less); + } + cluster->root = RB_ROOT; + spin_unlock(&cluster->lock); + btrfs_put_block_group(block_group); +} + +void btrfs_remove_free_space_cache(struct btrfs_block_group *block_group) +{ + struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl; + struct btrfs_free_cluster *cluster; + struct list_head *head; + + spin_lock(&ctl->tree_lock); + while ((head = block_group->cluster_list.next) != + &block_group->cluster_list) { + cluster = list_entry(head, struct btrfs_free_cluster, + block_group_list); + + WARN_ON(cluster->block_group != block_group); + __btrfs_return_cluster_to_free_space(block_group, cluster); + + cond_resched_lock(&ctl->tree_lock); + } + __btrfs_remove_free_space_cache(ctl); + btrfs_discard_update_discardable(block_group); + spin_unlock(&ctl->tree_lock); + +} + +/* + * Walk @block_group's free space rb_tree to determine if everything is trimmed. + */ +bool btrfs_is_free_space_trimmed(struct btrfs_block_group *block_group) +{ + struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl; + struct btrfs_free_space *info; + struct rb_node *node; + bool ret = true; + + spin_lock(&ctl->tree_lock); + node = rb_first(&ctl->free_space_offset); + + while (node) { + info = rb_entry(node, struct btrfs_free_space, offset_index); + + if (!btrfs_free_space_trimmed(info)) { + ret = false; + break; + } + + node = rb_next(node); + } + + spin_unlock(&ctl->tree_lock); + return ret; +} + +u64 btrfs_find_space_for_alloc(struct btrfs_block_group *block_group, + u64 offset, u64 bytes, u64 empty_size, + u64 *max_extent_size) +{ + struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl; + struct btrfs_discard_ctl *discard_ctl = + &block_group->fs_info->discard_ctl; + struct btrfs_free_space *entry = NULL; + u64 bytes_search = bytes + empty_size; + u64 ret = 0; + u64 align_gap = 0; + u64 align_gap_len = 0; + enum btrfs_trim_state align_gap_trim_state = BTRFS_TRIM_STATE_UNTRIMMED; + bool use_bytes_index = (offset == block_group->start); + + ASSERT(!btrfs_is_zoned(block_group->fs_info)); + + spin_lock(&ctl->tree_lock); + entry = find_free_space(ctl, &offset, &bytes_search, + block_group->full_stripe_len, max_extent_size, + use_bytes_index); + if (!entry) + goto out; + + ret = offset; + if (entry->bitmap) { + bitmap_clear_bits(ctl, entry, offset, bytes, true); + + if (!btrfs_free_space_trimmed(entry)) + atomic64_add(bytes, &discard_ctl->discard_bytes_saved); + + if (!entry->bytes) + free_bitmap(ctl, entry); + } else { + unlink_free_space(ctl, entry, true); + align_gap_len = offset - entry->offset; + align_gap = entry->offset; + align_gap_trim_state = entry->trim_state; + + if (!btrfs_free_space_trimmed(entry)) + atomic64_add(bytes, &discard_ctl->discard_bytes_saved); + + entry->offset = offset + bytes; + WARN_ON(entry->bytes < bytes + align_gap_len); + + entry->bytes -= bytes + align_gap_len; + if (!entry->bytes) + kmem_cache_free(btrfs_free_space_cachep, entry); + else + link_free_space(ctl, entry); + } +out: + btrfs_discard_update_discardable(block_group); + spin_unlock(&ctl->tree_lock); + + if (align_gap_len) + __btrfs_add_free_space(block_group, align_gap, align_gap_len, + align_gap_trim_state); + return ret; +} + +/* + * given a cluster, put all of its extents back into the free space + * cache. If a block group is passed, this function will only free + * a cluster that belongs to the passed block group. + * + * Otherwise, it'll get a reference on the block group pointed to by the + * cluster and remove the cluster from it. + */ +void btrfs_return_cluster_to_free_space( + struct btrfs_block_group *block_group, + struct btrfs_free_cluster *cluster) +{ + struct btrfs_free_space_ctl *ctl; + + /* first, get a safe pointer to the block group */ + spin_lock(&cluster->lock); + if (!block_group) { + block_group = cluster->block_group; + if (!block_group) { + spin_unlock(&cluster->lock); + return; + } + } else if (cluster->block_group != block_group) { + /* someone else has already freed it don't redo their work */ + spin_unlock(&cluster->lock); + return; + } + btrfs_get_block_group(block_group); + spin_unlock(&cluster->lock); + + ctl = block_group->free_space_ctl; + + /* now return any extents the cluster had on it */ + spin_lock(&ctl->tree_lock); + __btrfs_return_cluster_to_free_space(block_group, cluster); + spin_unlock(&ctl->tree_lock); + + btrfs_discard_queue_work(&block_group->fs_info->discard_ctl, block_group); + + /* finally drop our ref */ + btrfs_put_block_group(block_group); +} + +static u64 btrfs_alloc_from_bitmap(struct btrfs_block_group *block_group, + struct btrfs_free_cluster *cluster, + struct btrfs_free_space *entry, + u64 bytes, u64 min_start, + u64 *max_extent_size) +{ + struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl; + int err; + u64 search_start = cluster->window_start; + u64 search_bytes = bytes; + u64 ret = 0; + + search_start = min_start; + search_bytes = bytes; + + err = search_bitmap(ctl, entry, &search_start, &search_bytes, true); + if (err) { + *max_extent_size = max(get_max_extent_size(entry), + *max_extent_size); + return 0; + } + + ret = search_start; + bitmap_clear_bits(ctl, entry, ret, bytes, false); + + return ret; +} + +/* + * given a cluster, try to allocate 'bytes' from it, returns 0 + * if it couldn't find anything suitably large, or a logical disk offset + * if things worked out + */ +u64 btrfs_alloc_from_cluster(struct btrfs_block_group *block_group, + struct btrfs_free_cluster *cluster, u64 bytes, + u64 min_start, u64 *max_extent_size) +{ + struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl; + struct btrfs_discard_ctl *discard_ctl = + &block_group->fs_info->discard_ctl; + struct btrfs_free_space *entry = NULL; + struct rb_node *node; + u64 ret = 0; + + ASSERT(!btrfs_is_zoned(block_group->fs_info)); + + spin_lock(&cluster->lock); + if (bytes > cluster->max_size) + goto out; + + if (cluster->block_group != block_group) + goto out; + + node = rb_first(&cluster->root); + if (!node) + goto out; + + entry = rb_entry(node, struct btrfs_free_space, offset_index); + while (1) { + if (entry->bytes < bytes) + *max_extent_size = max(get_max_extent_size(entry), + *max_extent_size); + + if (entry->bytes < bytes || + (!entry->bitmap && entry->offset < min_start)) { + node = rb_next(&entry->offset_index); + if (!node) + break; + entry = rb_entry(node, struct btrfs_free_space, + offset_index); + continue; + } + + if (entry->bitmap) { + ret = btrfs_alloc_from_bitmap(block_group, + cluster, entry, bytes, + cluster->window_start, + max_extent_size); + if (ret == 0) { + node = rb_next(&entry->offset_index); + if (!node) + break; + entry = rb_entry(node, struct btrfs_free_space, + offset_index); + continue; + } + cluster->window_start += bytes; + } else { + ret = entry->offset; + + entry->offset += bytes; + entry->bytes -= bytes; + } + + break; + } +out: + spin_unlock(&cluster->lock); + + if (!ret) + return 0; + + spin_lock(&ctl->tree_lock); + + if (!btrfs_free_space_trimmed(entry)) + atomic64_add(bytes, &discard_ctl->discard_bytes_saved); + + ctl->free_space -= bytes; + if (!entry->bitmap && !btrfs_free_space_trimmed(entry)) + ctl->discardable_bytes[BTRFS_STAT_CURR] -= bytes; + + spin_lock(&cluster->lock); + if (entry->bytes == 0) { + rb_erase(&entry->offset_index, &cluster->root); + ctl->free_extents--; + if (entry->bitmap) { + kmem_cache_free(btrfs_free_space_bitmap_cachep, + entry->bitmap); + ctl->total_bitmaps--; + recalculate_thresholds(ctl); + } else if (!btrfs_free_space_trimmed(entry)) { + ctl->discardable_extents[BTRFS_STAT_CURR]--; + } + kmem_cache_free(btrfs_free_space_cachep, entry); + } + + spin_unlock(&cluster->lock); + spin_unlock(&ctl->tree_lock); + + return ret; +} + +static int btrfs_bitmap_cluster(struct btrfs_block_group *block_group, + struct btrfs_free_space *entry, + struct btrfs_free_cluster *cluster, + u64 offset, u64 bytes, + u64 cont1_bytes, u64 min_bytes) +{ + struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl; + unsigned long next_zero; + unsigned long i; + unsigned long want_bits; + unsigned long min_bits; + unsigned long found_bits; + unsigned long max_bits = 0; + unsigned long start = 0; + unsigned long total_found = 0; + int ret; + + lockdep_assert_held(&ctl->tree_lock); + + i = offset_to_bit(entry->offset, ctl->unit, + max_t(u64, offset, entry->offset)); + want_bits = bytes_to_bits(bytes, ctl->unit); + min_bits = bytes_to_bits(min_bytes, ctl->unit); + + /* + * Don't bother looking for a cluster in this bitmap if it's heavily + * fragmented. + */ + if (entry->max_extent_size && + entry->max_extent_size < cont1_bytes) + return -ENOSPC; +again: + found_bits = 0; + for_each_set_bit_from(i, entry->bitmap, BITS_PER_BITMAP) { + next_zero = find_next_zero_bit(entry->bitmap, + BITS_PER_BITMAP, i); + if (next_zero - i >= min_bits) { + found_bits = next_zero - i; + if (found_bits > max_bits) + max_bits = found_bits; + break; + } + if (next_zero - i > max_bits) + max_bits = next_zero - i; + i = next_zero; + } + + if (!found_bits) { + entry->max_extent_size = (u64)max_bits * ctl->unit; + return -ENOSPC; + } + + if (!total_found) { + start = i; + cluster->max_size = 0; + } + + total_found += found_bits; + + if (cluster->max_size < found_bits * ctl->unit) + cluster->max_size = found_bits * ctl->unit; + + if (total_found < want_bits || cluster->max_size < cont1_bytes) { + i = next_zero + 1; + goto again; + } + + cluster->window_start = start * ctl->unit + entry->offset; + rb_erase(&entry->offset_index, &ctl->free_space_offset); + rb_erase_cached(&entry->bytes_index, &ctl->free_space_bytes); + + /* + * We need to know if we're currently on the normal space index when we + * manipulate the bitmap so that we know we need to remove and re-insert + * it into the space_index tree. Clear the bytes_index node here so the + * bitmap manipulation helpers know not to mess with the space_index + * until this bitmap entry is added back into the normal cache. + */ + RB_CLEAR_NODE(&entry->bytes_index); + + ret = tree_insert_offset(ctl, cluster, entry); + ASSERT(!ret); /* -EEXIST; Logic error */ + + trace_btrfs_setup_cluster(block_group, cluster, + total_found * ctl->unit, 1); + return 0; +} + +/* + * This searches the block group for just extents to fill the cluster with. + * Try to find a cluster with at least bytes total bytes, at least one + * extent of cont1_bytes, and other clusters of at least min_bytes. + */ +static noinline int +setup_cluster_no_bitmap(struct btrfs_block_group *block_group, + struct btrfs_free_cluster *cluster, + struct list_head *bitmaps, u64 offset, u64 bytes, + u64 cont1_bytes, u64 min_bytes) +{ + struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl; + struct btrfs_free_space *first = NULL; + struct btrfs_free_space *entry = NULL; + struct btrfs_free_space *last; + struct rb_node *node; + u64 window_free; + u64 max_extent; + u64 total_size = 0; + + lockdep_assert_held(&ctl->tree_lock); + + entry = tree_search_offset(ctl, offset, 0, 1); + if (!entry) + return -ENOSPC; + + /* + * We don't want bitmaps, so just move along until we find a normal + * extent entry. + */ + while (entry->bitmap || entry->bytes < min_bytes) { + if (entry->bitmap && list_empty(&entry->list)) + list_add_tail(&entry->list, bitmaps); + node = rb_next(&entry->offset_index); + if (!node) + return -ENOSPC; + entry = rb_entry(node, struct btrfs_free_space, offset_index); + } + + window_free = entry->bytes; + max_extent = entry->bytes; + first = entry; + last = entry; + + for (node = rb_next(&entry->offset_index); node; + node = rb_next(&entry->offset_index)) { + entry = rb_entry(node, struct btrfs_free_space, offset_index); + + if (entry->bitmap) { + if (list_empty(&entry->list)) + list_add_tail(&entry->list, bitmaps); + continue; + } + + if (entry->bytes < min_bytes) + continue; + + last = entry; + window_free += entry->bytes; + if (entry->bytes > max_extent) + max_extent = entry->bytes; + } + + if (window_free < bytes || max_extent < cont1_bytes) + return -ENOSPC; + + cluster->window_start = first->offset; + + node = &first->offset_index; + + /* + * now we've found our entries, pull them out of the free space + * cache and put them into the cluster rbtree + */ + do { + int ret; + + entry = rb_entry(node, struct btrfs_free_space, offset_index); + node = rb_next(&entry->offset_index); + if (entry->bitmap || entry->bytes < min_bytes) + continue; + + rb_erase(&entry->offset_index, &ctl->free_space_offset); + rb_erase_cached(&entry->bytes_index, &ctl->free_space_bytes); + ret = tree_insert_offset(ctl, cluster, entry); + total_size += entry->bytes; + ASSERT(!ret); /* -EEXIST; Logic error */ + } while (node && entry != last); + + cluster->max_size = max_extent; + trace_btrfs_setup_cluster(block_group, cluster, total_size, 0); + return 0; +} + +/* + * This specifically looks for bitmaps that may work in the cluster, we assume + * that we have already failed to find extents that will work. + */ +static noinline int +setup_cluster_bitmap(struct btrfs_block_group *block_group, + struct btrfs_free_cluster *cluster, + struct list_head *bitmaps, u64 offset, u64 bytes, + u64 cont1_bytes, u64 min_bytes) +{ + struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl; + struct btrfs_free_space *entry = NULL; + int ret = -ENOSPC; + u64 bitmap_offset = offset_to_bitmap(ctl, offset); + + if (ctl->total_bitmaps == 0) + return -ENOSPC; + + /* + * The bitmap that covers offset won't be in the list unless offset + * is just its start offset. + */ + if (!list_empty(bitmaps)) + entry = list_first_entry(bitmaps, struct btrfs_free_space, list); + + if (!entry || entry->offset != bitmap_offset) { + entry = tree_search_offset(ctl, bitmap_offset, 1, 0); + if (entry && list_empty(&entry->list)) + list_add(&entry->list, bitmaps); + } + + list_for_each_entry(entry, bitmaps, list) { + if (entry->bytes < bytes) + continue; + ret = btrfs_bitmap_cluster(block_group, entry, cluster, offset, + bytes, cont1_bytes, min_bytes); + if (!ret) + return 0; + } + + /* + * The bitmaps list has all the bitmaps that record free space + * starting after offset, so no more search is required. + */ + return -ENOSPC; +} + +/* + * here we try to find a cluster of blocks in a block group. The goal + * is to find at least bytes+empty_size. + * We might not find them all in one contiguous area. + * + * returns zero and sets up cluster if things worked out, otherwise + * it returns -enospc + */ +int btrfs_find_space_cluster(struct btrfs_block_group *block_group, + struct btrfs_free_cluster *cluster, + u64 offset, u64 bytes, u64 empty_size) +{ + struct btrfs_fs_info *fs_info = block_group->fs_info; + struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl; + struct btrfs_free_space *entry, *tmp; + LIST_HEAD(bitmaps); + u64 min_bytes; + u64 cont1_bytes; + int ret; + + /* + * Choose the minimum extent size we'll require for this + * cluster. For SSD_SPREAD, don't allow any fragmentation. + * For metadata, allow allocates with smaller extents. For + * data, keep it dense. + */ + if (btrfs_test_opt(fs_info, SSD_SPREAD)) { + cont1_bytes = bytes + empty_size; + min_bytes = cont1_bytes; + } else if (block_group->flags & BTRFS_BLOCK_GROUP_METADATA) { + cont1_bytes = bytes; + min_bytes = fs_info->sectorsize; + } else { + cont1_bytes = max(bytes, (bytes + empty_size) >> 2); + min_bytes = fs_info->sectorsize; + } + + spin_lock(&ctl->tree_lock); + + /* + * If we know we don't have enough space to make a cluster don't even + * bother doing all the work to try and find one. + */ + if (ctl->free_space < bytes) { + spin_unlock(&ctl->tree_lock); + return -ENOSPC; + } + + spin_lock(&cluster->lock); + + /* someone already found a cluster, hooray */ + if (cluster->block_group) { + ret = 0; + goto out; + } + + trace_btrfs_find_cluster(block_group, offset, bytes, empty_size, + min_bytes); + + ret = setup_cluster_no_bitmap(block_group, cluster, &bitmaps, offset, + bytes + empty_size, + cont1_bytes, min_bytes); + if (ret) + ret = setup_cluster_bitmap(block_group, cluster, &bitmaps, + offset, bytes + empty_size, + cont1_bytes, min_bytes); + + /* Clear our temporary list */ + list_for_each_entry_safe(entry, tmp, &bitmaps, list) + list_del_init(&entry->list); + + if (!ret) { + btrfs_get_block_group(block_group); + list_add_tail(&cluster->block_group_list, + &block_group->cluster_list); + cluster->block_group = block_group; + } else { + trace_btrfs_failed_cluster_setup(block_group); + } +out: + spin_unlock(&cluster->lock); + spin_unlock(&ctl->tree_lock); + + return ret; +} + +/* + * simple code to zero out a cluster + */ +void btrfs_init_free_cluster(struct btrfs_free_cluster *cluster) +{ + spin_lock_init(&cluster->lock); + spin_lock_init(&cluster->refill_lock); + cluster->root = RB_ROOT; + cluster->max_size = 0; + cluster->fragmented = false; + INIT_LIST_HEAD(&cluster->block_group_list); + cluster->block_group = NULL; +} + +static int do_trimming(struct btrfs_block_group *block_group, + u64 *total_trimmed, u64 start, u64 bytes, + u64 reserved_start, u64 reserved_bytes, + enum btrfs_trim_state reserved_trim_state, + struct btrfs_trim_range *trim_entry) +{ + struct btrfs_space_info *space_info = block_group->space_info; + struct btrfs_fs_info *fs_info = block_group->fs_info; + struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl; + int ret; + int update = 0; + const u64 end = start + bytes; + const u64 reserved_end = reserved_start + reserved_bytes; + enum btrfs_trim_state trim_state = BTRFS_TRIM_STATE_UNTRIMMED; + u64 trimmed = 0; + + spin_lock(&space_info->lock); + spin_lock(&block_group->lock); + if (!block_group->ro) { + block_group->reserved += reserved_bytes; + space_info->bytes_reserved += reserved_bytes; + update = 1; + } + spin_unlock(&block_group->lock); + spin_unlock(&space_info->lock); + + ret = btrfs_discard_extent(fs_info, start, bytes, &trimmed); + if (!ret) { + *total_trimmed += trimmed; + trim_state = BTRFS_TRIM_STATE_TRIMMED; + } + + mutex_lock(&ctl->cache_writeout_mutex); + if (reserved_start < start) + __btrfs_add_free_space(block_group, reserved_start, + start - reserved_start, + reserved_trim_state); + if (end < reserved_end) + __btrfs_add_free_space(block_group, end, reserved_end - end, + reserved_trim_state); + __btrfs_add_free_space(block_group, start, bytes, trim_state); + list_del(&trim_entry->list); + mutex_unlock(&ctl->cache_writeout_mutex); + + if (update) { + spin_lock(&space_info->lock); + spin_lock(&block_group->lock); + if (block_group->ro) + space_info->bytes_readonly += reserved_bytes; + block_group->reserved -= reserved_bytes; + space_info->bytes_reserved -= reserved_bytes; + spin_unlock(&block_group->lock); + spin_unlock(&space_info->lock); + } + + return ret; +} + +/* + * If @async is set, then we will trim 1 region and return. + */ +static int trim_no_bitmap(struct btrfs_block_group *block_group, + u64 *total_trimmed, u64 start, u64 end, u64 minlen, + bool async) +{ + struct btrfs_discard_ctl *discard_ctl = + &block_group->fs_info->discard_ctl; + struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl; + struct btrfs_free_space *entry; + struct rb_node *node; + int ret = 0; + u64 extent_start; + u64 extent_bytes; + enum btrfs_trim_state extent_trim_state; + u64 bytes; + const u64 max_discard_size = READ_ONCE(discard_ctl->max_discard_size); + + while (start < end) { + struct btrfs_trim_range trim_entry; + + mutex_lock(&ctl->cache_writeout_mutex); + spin_lock(&ctl->tree_lock); + + if (ctl->free_space < minlen) + goto out_unlock; + + entry = tree_search_offset(ctl, start, 0, 1); + if (!entry) + goto out_unlock; + + /* Skip bitmaps and if async, already trimmed entries */ + while (entry->bitmap || + (async && btrfs_free_space_trimmed(entry))) { + node = rb_next(&entry->offset_index); + if (!node) + goto out_unlock; + entry = rb_entry(node, struct btrfs_free_space, + offset_index); + } + + if (entry->offset >= end) + goto out_unlock; + + extent_start = entry->offset; + extent_bytes = entry->bytes; + extent_trim_state = entry->trim_state; + if (async) { + start = entry->offset; + bytes = entry->bytes; + if (bytes < minlen) { + spin_unlock(&ctl->tree_lock); + mutex_unlock(&ctl->cache_writeout_mutex); + goto next; + } + unlink_free_space(ctl, entry, true); + /* + * Let bytes = BTRFS_MAX_DISCARD_SIZE + X. + * If X < BTRFS_ASYNC_DISCARD_MIN_FILTER, we won't trim + * X when we come back around. So trim it now. + */ + if (max_discard_size && + bytes >= (max_discard_size + + BTRFS_ASYNC_DISCARD_MIN_FILTER)) { + bytes = max_discard_size; + extent_bytes = max_discard_size; + entry->offset += max_discard_size; + entry->bytes -= max_discard_size; + link_free_space(ctl, entry); + } else { + kmem_cache_free(btrfs_free_space_cachep, entry); + } + } else { + start = max(start, extent_start); + bytes = min(extent_start + extent_bytes, end) - start; + if (bytes < minlen) { + spin_unlock(&ctl->tree_lock); + mutex_unlock(&ctl->cache_writeout_mutex); + goto next; + } + + unlink_free_space(ctl, entry, true); + kmem_cache_free(btrfs_free_space_cachep, entry); + } + + spin_unlock(&ctl->tree_lock); + trim_entry.start = extent_start; + trim_entry.bytes = extent_bytes; + list_add_tail(&trim_entry.list, &ctl->trimming_ranges); + mutex_unlock(&ctl->cache_writeout_mutex); + + ret = do_trimming(block_group, total_trimmed, start, bytes, + extent_start, extent_bytes, extent_trim_state, + &trim_entry); + if (ret) { + block_group->discard_cursor = start + bytes; + break; + } +next: + start += bytes; + block_group->discard_cursor = start; + if (async && *total_trimmed) + break; + + if (fatal_signal_pending(current)) { + ret = -ERESTARTSYS; + break; + } + + cond_resched(); + } + + return ret; + +out_unlock: + block_group->discard_cursor = btrfs_block_group_end(block_group); + spin_unlock(&ctl->tree_lock); + mutex_unlock(&ctl->cache_writeout_mutex); + + return ret; +} + +/* + * If we break out of trimming a bitmap prematurely, we should reset the + * trimming bit. In a rather contrieved case, it's possible to race here so + * reset the state to BTRFS_TRIM_STATE_UNTRIMMED. + * + * start = start of bitmap + * end = near end of bitmap + * + * Thread 1: Thread 2: + * trim_bitmaps(start) + * trim_bitmaps(end) + * end_trimming_bitmap() + * reset_trimming_bitmap() + */ +static void reset_trimming_bitmap(struct btrfs_free_space_ctl *ctl, u64 offset) +{ + struct btrfs_free_space *entry; + + spin_lock(&ctl->tree_lock); + entry = tree_search_offset(ctl, offset, 1, 0); + if (entry) { + if (btrfs_free_space_trimmed(entry)) { + ctl->discardable_extents[BTRFS_STAT_CURR] += + entry->bitmap_extents; + ctl->discardable_bytes[BTRFS_STAT_CURR] += entry->bytes; + } + entry->trim_state = BTRFS_TRIM_STATE_UNTRIMMED; + } + + spin_unlock(&ctl->tree_lock); +} + +static void end_trimming_bitmap(struct btrfs_free_space_ctl *ctl, + struct btrfs_free_space *entry) +{ + if (btrfs_free_space_trimming_bitmap(entry)) { + entry->trim_state = BTRFS_TRIM_STATE_TRIMMED; + ctl->discardable_extents[BTRFS_STAT_CURR] -= + entry->bitmap_extents; + ctl->discardable_bytes[BTRFS_STAT_CURR] -= entry->bytes; + } +} + +/* + * If @async is set, then we will trim 1 region and return. + */ +static int trim_bitmaps(struct btrfs_block_group *block_group, + u64 *total_trimmed, u64 start, u64 end, u64 minlen, + u64 maxlen, bool async) +{ + struct btrfs_discard_ctl *discard_ctl = + &block_group->fs_info->discard_ctl; + struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl; + struct btrfs_free_space *entry; + int ret = 0; + int ret2; + u64 bytes; + u64 offset = offset_to_bitmap(ctl, start); + const u64 max_discard_size = READ_ONCE(discard_ctl->max_discard_size); + + while (offset < end) { + bool next_bitmap = false; + struct btrfs_trim_range trim_entry; + + mutex_lock(&ctl->cache_writeout_mutex); + spin_lock(&ctl->tree_lock); + + if (ctl->free_space < minlen) { + block_group->discard_cursor = + btrfs_block_group_end(block_group); + spin_unlock(&ctl->tree_lock); + mutex_unlock(&ctl->cache_writeout_mutex); + break; + } + + entry = tree_search_offset(ctl, offset, 1, 0); + /* + * Bitmaps are marked trimmed lossily now to prevent constant + * discarding of the same bitmap (the reason why we are bound + * by the filters). So, retrim the block group bitmaps when we + * are preparing to punt to the unused_bgs list. This uses + * @minlen to determine if we are in BTRFS_DISCARD_INDEX_UNUSED + * which is the only discard index which sets minlen to 0. + */ + if (!entry || (async && minlen && start == offset && + btrfs_free_space_trimmed(entry))) { + spin_unlock(&ctl->tree_lock); + mutex_unlock(&ctl->cache_writeout_mutex); + next_bitmap = true; + goto next; + } + + /* + * Async discard bitmap trimming begins at by setting the start + * to be key.objectid and the offset_to_bitmap() aligns to the + * start of the bitmap. This lets us know we are fully + * scanning the bitmap rather than only some portion of it. + */ + if (start == offset) + entry->trim_state = BTRFS_TRIM_STATE_TRIMMING; + + bytes = minlen; + ret2 = search_bitmap(ctl, entry, &start, &bytes, false); + if (ret2 || start >= end) { + /* + * We lossily consider a bitmap trimmed if we only skip + * over regions <= BTRFS_ASYNC_DISCARD_MIN_FILTER. + */ + if (ret2 && minlen <= BTRFS_ASYNC_DISCARD_MIN_FILTER) + end_trimming_bitmap(ctl, entry); + else + entry->trim_state = BTRFS_TRIM_STATE_UNTRIMMED; + spin_unlock(&ctl->tree_lock); + mutex_unlock(&ctl->cache_writeout_mutex); + next_bitmap = true; + goto next; + } + + /* + * We already trimmed a region, but are using the locking above + * to reset the trim_state. + */ + if (async && *total_trimmed) { + spin_unlock(&ctl->tree_lock); + mutex_unlock(&ctl->cache_writeout_mutex); + goto out; + } + + bytes = min(bytes, end - start); + if (bytes < minlen || (async && maxlen && bytes > maxlen)) { + spin_unlock(&ctl->tree_lock); + mutex_unlock(&ctl->cache_writeout_mutex); + goto next; + } + + /* + * Let bytes = BTRFS_MAX_DISCARD_SIZE + X. + * If X < @minlen, we won't trim X when we come back around. + * So trim it now. We differ here from trimming extents as we + * don't keep individual state per bit. + */ + if (async && + max_discard_size && + bytes > (max_discard_size + minlen)) + bytes = max_discard_size; + + bitmap_clear_bits(ctl, entry, start, bytes, true); + if (entry->bytes == 0) + free_bitmap(ctl, entry); + + spin_unlock(&ctl->tree_lock); + trim_entry.start = start; + trim_entry.bytes = bytes; + list_add_tail(&trim_entry.list, &ctl->trimming_ranges); + mutex_unlock(&ctl->cache_writeout_mutex); + + ret = do_trimming(block_group, total_trimmed, start, bytes, + start, bytes, 0, &trim_entry); + if (ret) { + reset_trimming_bitmap(ctl, offset); + block_group->discard_cursor = + btrfs_block_group_end(block_group); + break; + } +next: + if (next_bitmap) { + offset += BITS_PER_BITMAP * ctl->unit; + start = offset; + } else { + start += bytes; + } + block_group->discard_cursor = start; + + if (fatal_signal_pending(current)) { + if (start != offset) + reset_trimming_bitmap(ctl, offset); + ret = -ERESTARTSYS; + break; + } + + cond_resched(); + } + + if (offset >= end) + block_group->discard_cursor = end; + +out: + return ret; +} + +int btrfs_trim_block_group(struct btrfs_block_group *block_group, + u64 *trimmed, u64 start, u64 end, u64 minlen) +{ + struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl; + int ret; + u64 rem = 0; + + ASSERT(!btrfs_is_zoned(block_group->fs_info)); + + *trimmed = 0; + + spin_lock(&block_group->lock); + if (test_bit(BLOCK_GROUP_FLAG_REMOVED, &block_group->runtime_flags)) { + spin_unlock(&block_group->lock); + return 0; + } + btrfs_freeze_block_group(block_group); + spin_unlock(&block_group->lock); + + ret = trim_no_bitmap(block_group, trimmed, start, end, minlen, false); + if (ret) + goto out; + + ret = trim_bitmaps(block_group, trimmed, start, end, minlen, 0, false); + div64_u64_rem(end, BITS_PER_BITMAP * ctl->unit, &rem); + /* If we ended in the middle of a bitmap, reset the trimming flag */ + if (rem) + reset_trimming_bitmap(ctl, offset_to_bitmap(ctl, end)); +out: + btrfs_unfreeze_block_group(block_group); + return ret; +} + +int btrfs_trim_block_group_extents(struct btrfs_block_group *block_group, + u64 *trimmed, u64 start, u64 end, u64 minlen, + bool async) +{ + int ret; + + *trimmed = 0; + + spin_lock(&block_group->lock); + if (test_bit(BLOCK_GROUP_FLAG_REMOVED, &block_group->runtime_flags)) { + spin_unlock(&block_group->lock); + return 0; + } + btrfs_freeze_block_group(block_group); + spin_unlock(&block_group->lock); + + ret = trim_no_bitmap(block_group, trimmed, start, end, minlen, async); + btrfs_unfreeze_block_group(block_group); + + return ret; +} + +int btrfs_trim_block_group_bitmaps(struct btrfs_block_group *block_group, + u64 *trimmed, u64 start, u64 end, u64 minlen, + u64 maxlen, bool async) +{ + int ret; + + *trimmed = 0; + + spin_lock(&block_group->lock); + if (test_bit(BLOCK_GROUP_FLAG_REMOVED, &block_group->runtime_flags)) { + spin_unlock(&block_group->lock); + return 0; + } + btrfs_freeze_block_group(block_group); + spin_unlock(&block_group->lock); + + ret = trim_bitmaps(block_group, trimmed, start, end, minlen, maxlen, + async); + + btrfs_unfreeze_block_group(block_group); + + return ret; +} + +bool btrfs_free_space_cache_v1_active(struct btrfs_fs_info *fs_info) +{ + return btrfs_super_cache_generation(fs_info->super_copy); +} + +static int cleanup_free_space_cache_v1(struct btrfs_fs_info *fs_info, + struct btrfs_trans_handle *trans) +{ + struct btrfs_block_group *block_group; + struct rb_node *node; + int ret = 0; + + btrfs_info(fs_info, "cleaning free space cache v1"); + + node = rb_first_cached(&fs_info->block_group_cache_tree); + while (node) { + block_group = rb_entry(node, struct btrfs_block_group, cache_node); + ret = btrfs_remove_free_space_inode(trans, NULL, block_group); + if (ret) + goto out; + node = rb_next(node); + } +out: + return ret; +} + +int btrfs_set_free_space_cache_v1_active(struct btrfs_fs_info *fs_info, bool active) +{ + struct btrfs_trans_handle *trans; + int ret; + + /* + * update_super_roots will appropriately set or unset + * super_copy->cache_generation based on SPACE_CACHE and + * BTRFS_FS_CLEANUP_SPACE_CACHE_V1. For this reason, we need a + * transaction commit whether we are enabling space cache v1 and don't + * have any other work to do, or are disabling it and removing free + * space inodes. + */ + trans = btrfs_start_transaction(fs_info->tree_root, 0); + if (IS_ERR(trans)) + return PTR_ERR(trans); + + if (!active) { + set_bit(BTRFS_FS_CLEANUP_SPACE_CACHE_V1, &fs_info->flags); + ret = cleanup_free_space_cache_v1(fs_info, trans); + if (ret) { + btrfs_abort_transaction(trans, ret); + btrfs_end_transaction(trans); + goto out; + } + } + + ret = btrfs_commit_transaction(trans); +out: + clear_bit(BTRFS_FS_CLEANUP_SPACE_CACHE_V1, &fs_info->flags); + + return ret; +} + +int __init btrfs_free_space_init(void) +{ + btrfs_free_space_cachep = kmem_cache_create("btrfs_free_space", + sizeof(struct btrfs_free_space), 0, + SLAB_MEM_SPREAD, NULL); + if (!btrfs_free_space_cachep) + return -ENOMEM; + + btrfs_free_space_bitmap_cachep = kmem_cache_create("btrfs_free_space_bitmap", + PAGE_SIZE, PAGE_SIZE, + SLAB_MEM_SPREAD, NULL); + if (!btrfs_free_space_bitmap_cachep) { + kmem_cache_destroy(btrfs_free_space_cachep); + return -ENOMEM; + } + + return 0; +} + +void __cold btrfs_free_space_exit(void) +{ + kmem_cache_destroy(btrfs_free_space_cachep); + kmem_cache_destroy(btrfs_free_space_bitmap_cachep); +} + +#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS +/* + * Use this if you need to make a bitmap or extent entry specifically, it + * doesn't do any of the merging that add_free_space does, this acts a lot like + * how the free space cache loading stuff works, so you can get really weird + * configurations. + */ +int test_add_free_space_entry(struct btrfs_block_group *cache, + u64 offset, u64 bytes, bool bitmap) +{ + struct btrfs_free_space_ctl *ctl = cache->free_space_ctl; + struct btrfs_free_space *info = NULL, *bitmap_info; + void *map = NULL; + enum btrfs_trim_state trim_state = BTRFS_TRIM_STATE_TRIMMED; + u64 bytes_added; + int ret; + +again: + if (!info) { + info = kmem_cache_zalloc(btrfs_free_space_cachep, GFP_NOFS); + if (!info) + return -ENOMEM; + } + + if (!bitmap) { + spin_lock(&ctl->tree_lock); + info->offset = offset; + info->bytes = bytes; + info->max_extent_size = 0; + ret = link_free_space(ctl, info); + spin_unlock(&ctl->tree_lock); + if (ret) + kmem_cache_free(btrfs_free_space_cachep, info); + return ret; + } + + if (!map) { + map = kmem_cache_zalloc(btrfs_free_space_bitmap_cachep, GFP_NOFS); + if (!map) { + kmem_cache_free(btrfs_free_space_cachep, info); + return -ENOMEM; + } + } + + spin_lock(&ctl->tree_lock); + bitmap_info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset), + 1, 0); + if (!bitmap_info) { + info->bitmap = map; + map = NULL; + add_new_bitmap(ctl, info, offset); + bitmap_info = info; + info = NULL; + } + + bytes_added = add_bytes_to_bitmap(ctl, bitmap_info, offset, bytes, + trim_state); + + bytes -= bytes_added; + offset += bytes_added; + spin_unlock(&ctl->tree_lock); + + if (bytes) + goto again; + + if (info) + kmem_cache_free(btrfs_free_space_cachep, info); + if (map) + kmem_cache_free(btrfs_free_space_bitmap_cachep, map); + return 0; +} + +/* + * Checks to see if the given range is in the free space cache. This is really + * just used to check the absence of space, so if there is free space in the + * range at all we will return 1. + */ +int test_check_exists(struct btrfs_block_group *cache, + u64 offset, u64 bytes) +{ + struct btrfs_free_space_ctl *ctl = cache->free_space_ctl; + struct btrfs_free_space *info; + int ret = 0; + + spin_lock(&ctl->tree_lock); + info = tree_search_offset(ctl, offset, 0, 0); + if (!info) { + info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset), + 1, 0); + if (!info) + goto out; + } + +have_info: + if (info->bitmap) { + u64 bit_off, bit_bytes; + struct rb_node *n; + struct btrfs_free_space *tmp; + + bit_off = offset; + bit_bytes = ctl->unit; + ret = search_bitmap(ctl, info, &bit_off, &bit_bytes, false); + if (!ret) { + if (bit_off == offset) { + ret = 1; + goto out; + } else if (bit_off > offset && + offset + bytes > bit_off) { + ret = 1; + goto out; + } + } + + n = rb_prev(&info->offset_index); + while (n) { + tmp = rb_entry(n, struct btrfs_free_space, + offset_index); + if (tmp->offset + tmp->bytes < offset) + break; + if (offset + bytes < tmp->offset) { + n = rb_prev(&tmp->offset_index); + continue; + } + info = tmp; + goto have_info; + } + + n = rb_next(&info->offset_index); + while (n) { + tmp = rb_entry(n, struct btrfs_free_space, + offset_index); + if (offset + bytes < tmp->offset) + break; + if (tmp->offset + tmp->bytes < offset) { + n = rb_next(&tmp->offset_index); + continue; + } + info = tmp; + goto have_info; + } + + ret = 0; + goto out; + } + + if (info->offset == offset) { + ret = 1; + goto out; + } + + if (offset > info->offset && offset < info->offset + info->bytes) + ret = 1; +out: + spin_unlock(&ctl->tree_lock); + return ret; +} +#endif /* CONFIG_BTRFS_FS_RUN_SANITY_TESTS */ |