/* * Copyright (C) 2015 Facebook. All rights reserved. * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public * License v2 as published by the Free Software Foundation. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * General Public License for more details. * * You should have received a copy of the GNU General Public * License along with this program; if not, write to the * Free Software Foundation, Inc., 59 Temple Place - Suite 330, * Boston, MA 021110-1307, USA. */ #include <linux/kernel.h> #include <linux/vmalloc.h> #include "ctree.h" #include "disk-io.h" #include "locking.h" #include "free-space-tree.h" #include "transaction.h" static int __add_block_group_free_space(struct btrfs_trans_handle *trans, struct btrfs_fs_info *fs_info, struct btrfs_block_group_cache *block_group, struct btrfs_path *path); void set_free_space_tree_thresholds(struct btrfs_block_group_cache *cache) { u32 bitmap_range; size_t bitmap_size; u64 num_bitmaps, total_bitmap_size; /* * We convert to bitmaps when the disk space required for using extents * exceeds that required for using bitmaps. */ bitmap_range = cache->fs_info->sectorsize * BTRFS_FREE_SPACE_BITMAP_BITS; num_bitmaps = div_u64(cache->key.offset + bitmap_range - 1, bitmap_range); bitmap_size = sizeof(struct btrfs_item) + BTRFS_FREE_SPACE_BITMAP_SIZE; total_bitmap_size = num_bitmaps * bitmap_size; cache->bitmap_high_thresh = div_u64(total_bitmap_size, sizeof(struct btrfs_item)); /* * We allow for a small buffer between the high threshold and low * threshold to avoid thrashing back and forth between the two formats. */ if (cache->bitmap_high_thresh > 100) cache->bitmap_low_thresh = cache->bitmap_high_thresh - 100; else cache->bitmap_low_thresh = 0; } static int add_new_free_space_info(struct btrfs_trans_handle *trans, struct btrfs_fs_info *fs_info, struct btrfs_block_group_cache *block_group, struct btrfs_path *path) { struct btrfs_root *root = fs_info->free_space_root; struct btrfs_free_space_info *info; struct btrfs_key key; struct extent_buffer *leaf; int ret; key.objectid = block_group->key.objectid; key.type = BTRFS_FREE_SPACE_INFO_KEY; key.offset = block_group->key.offset; ret = btrfs_insert_empty_item(trans, root, path, &key, sizeof(*info)); if (ret) goto out; leaf = path->nodes[0]; info = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_free_space_info); btrfs_set_free_space_extent_count(leaf, info, 0); btrfs_set_free_space_flags(leaf, info, 0); btrfs_mark_buffer_dirty(leaf); ret = 0; out: btrfs_release_path(path); return ret; } struct btrfs_free_space_info * search_free_space_info(struct btrfs_trans_handle *trans, struct btrfs_fs_info *fs_info, struct btrfs_block_group_cache *block_group, struct btrfs_path *path, int cow) { struct btrfs_root *root = fs_info->free_space_root; struct btrfs_key key; int ret; key.objectid = block_group->key.objectid; key.type = BTRFS_FREE_SPACE_INFO_KEY; key.offset = block_group->key.offset; ret = btrfs_search_slot(trans, root, &key, path, 0, cow); if (ret < 0) return ERR_PTR(ret); if (ret != 0) { btrfs_warn(fs_info, "missing free space info for %llu", block_group->key.objectid); ASSERT(0); return ERR_PTR(-ENOENT); } return btrfs_item_ptr(path->nodes[0], path->slots[0], struct btrfs_free_space_info); } /* * btrfs_search_slot() but we're looking for the greatest key less than the * passed key. */ static int btrfs_search_prev_slot(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct btrfs_key *key, struct btrfs_path *p, int ins_len, int cow) { int ret; ret = btrfs_search_slot(trans, root, key, p, ins_len, cow); if (ret < 0) return ret; if (ret == 0) { ASSERT(0); return -EIO; } if (p->slots[0] == 0) { ASSERT(0); return -EIO; } p->slots[0]--; return 0; } static inline u32 free_space_bitmap_size(u64 size, u32 sectorsize) { return DIV_ROUND_UP((u32)div_u64(size, sectorsize), BITS_PER_BYTE); } static u8 *alloc_bitmap(u32 bitmap_size) { void *mem; /* * The allocation size varies, observed numbers were < 4K up to 16K. * Using vmalloc unconditionally would be too heavy, we'll try * contiguous allocations first. */ if (bitmap_size <= PAGE_SIZE) return kzalloc(bitmap_size, GFP_NOFS); mem = kzalloc(bitmap_size, GFP_NOFS | __GFP_NOWARN); if (mem) return mem; return __vmalloc(bitmap_size, GFP_NOFS | __GFP_HIGHMEM | __GFP_ZERO, PAGE_KERNEL); } int convert_free_space_to_bitmaps(struct btrfs_trans_handle *trans, struct btrfs_fs_info *fs_info, struct btrfs_block_group_cache *block_group, struct btrfs_path *path) { struct btrfs_root *root = fs_info->free_space_root; struct btrfs_free_space_info *info; struct btrfs_key key, found_key; struct extent_buffer *leaf; u8 *bitmap, *bitmap_cursor; u64 start, end; u64 bitmap_range, i; u32 bitmap_size, flags, expected_extent_count; u32 extent_count = 0; int done = 0, nr; int ret; bitmap_size = free_space_bitmap_size(block_group->key.offset, fs_info->sectorsize); bitmap = alloc_bitmap(bitmap_size); if (!bitmap) { ret = -ENOMEM; goto out; } start = block_group->key.objectid; end = block_group->key.objectid + block_group->key.offset; key.objectid = end - 1; key.type = (u8)-1; key.offset = (u64)-1; while (!done) { ret = btrfs_search_prev_slot(trans, root, &key, path, -1, 1); if (ret) goto out; leaf = path->nodes[0]; nr = 0; path->slots[0]++; while (path->slots[0] > 0) { btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0] - 1); if (found_key.type == BTRFS_FREE_SPACE_INFO_KEY) { ASSERT(found_key.objectid == block_group->key.objectid); ASSERT(found_key.offset == block_group->key.offset); done = 1; break; } else if (found_key.type == BTRFS_FREE_SPACE_EXTENT_KEY) { u64 first, last; ASSERT(found_key.objectid >= start); ASSERT(found_key.objectid < end); ASSERT(found_key.objectid + found_key.offset <= end); first = div_u64(found_key.objectid - start, fs_info->sectorsize); last = div_u64(found_key.objectid + found_key.offset - start, fs_info->sectorsize); le_bitmap_set(bitmap, first, last - first); extent_count++; nr++; path->slots[0]--; } else { ASSERT(0); } } ret = btrfs_del_items(trans, root, path, path->slots[0], nr); if (ret) goto out; btrfs_release_path(path); } info = search_free_space_info(trans, fs_info, block_group, path, 1); if (IS_ERR(info)) { ret = PTR_ERR(info); goto out; } leaf = path->nodes[0]; flags = btrfs_free_space_flags(leaf, info); flags |= BTRFS_FREE_SPACE_USING_BITMAPS; btrfs_set_free_space_flags(leaf, info, flags); expected_extent_count = btrfs_free_space_extent_count(leaf, info); btrfs_mark_buffer_dirty(leaf); btrfs_release_path(path); if (extent_count != expected_extent_count) { btrfs_err(fs_info, "incorrect extent count for %llu; counted %u, expected %u", block_group->key.objectid, extent_count, expected_extent_count); ASSERT(0); ret = -EIO; goto out; } bitmap_cursor = bitmap; bitmap_range = fs_info->sectorsize * BTRFS_FREE_SPACE_BITMAP_BITS; i = start; while (i < end) { unsigned long ptr; u64 extent_size; u32 data_size; extent_size = min(end - i, bitmap_range); data_size = free_space_bitmap_size(extent_size, fs_info->sectorsize); key.objectid = i; key.type = BTRFS_FREE_SPACE_BITMAP_KEY; key.offset = extent_size; ret = btrfs_insert_empty_item(trans, root, path, &key, data_size); if (ret) goto out; leaf = path->nodes[0]; ptr = btrfs_item_ptr_offset(leaf, path->slots[0]); write_extent_buffer(leaf, bitmap_cursor, ptr, data_size); btrfs_mark_buffer_dirty(leaf); btrfs_release_path(path); i += extent_size; bitmap_cursor += data_size; } ret = 0; out: kvfree(bitmap); if (ret) btrfs_abort_transaction(trans, ret); return ret; } int convert_free_space_to_extents(struct btrfs_trans_handle *trans, struct btrfs_fs_info *fs_info, struct btrfs_block_group_cache *block_group, struct btrfs_path *path) { struct btrfs_root *root = fs_info->free_space_root; struct btrfs_free_space_info *info; struct btrfs_key key, found_key; struct extent_buffer *leaf; u8 *bitmap; u64 start, end; /* Initialize to silence GCC. */ u64 extent_start = 0; u64 offset; u32 bitmap_size, flags, expected_extent_count; int prev_bit = 0, bit, bitnr; u32 extent_count = 0; int done = 0, nr; int ret; bitmap_size = free_space_bitmap_size(block_group->key.offset, fs_info->sectorsize); bitmap = alloc_bitmap(bitmap_size); if (!bitmap) { ret = -ENOMEM; goto out; } start = block_group->key.objectid; end = block_group->key.objectid + block_group->key.offset; key.objectid = end - 1; key.type = (u8)-1; key.offset = (u64)-1; while (!done) { ret = btrfs_search_prev_slot(trans, root, &key, path, -1, 1); if (ret) goto out; leaf = path->nodes[0]; nr = 0; path->slots[0]++; while (path->slots[0] > 0) { btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0] - 1); if (found_key.type == BTRFS_FREE_SPACE_INFO_KEY) { ASSERT(found_key.objectid == block_group->key.objectid); ASSERT(found_key.offset == block_group->key.offset); done = 1; break; } else if (found_key.type == BTRFS_FREE_SPACE_BITMAP_KEY) { unsigned long ptr; u8 *bitmap_cursor; u32 bitmap_pos, data_size; ASSERT(found_key.objectid >= start); ASSERT(found_key.objectid < end); ASSERT(found_key.objectid + found_key.offset <= end); bitmap_pos = div_u64(found_key.objectid - start, fs_info->sectorsize * BITS_PER_BYTE); bitmap_cursor = bitmap + bitmap_pos; data_size = free_space_bitmap_size(found_key.offset, fs_info->sectorsize); ptr = btrfs_item_ptr_offset(leaf, path->slots[0] - 1); read_extent_buffer(leaf, bitmap_cursor, ptr, data_size); nr++; path->slots[0]--; } else { ASSERT(0); } } ret = btrfs_del_items(trans, root, path, path->slots[0], nr); if (ret) goto out; btrfs_release_path(path); } info = search_free_space_info(trans, fs_info, block_group, path, 1); if (IS_ERR(info)) { ret = PTR_ERR(info); goto out; } leaf = path->nodes[0]; flags = btrfs_free_space_flags(leaf, info); flags &= ~BTRFS_FREE_SPACE_USING_BITMAPS; btrfs_set_free_space_flags(leaf, info, flags); expected_extent_count = btrfs_free_space_extent_count(leaf, info); btrfs_mark_buffer_dirty(leaf); btrfs_release_path(path); offset = start; bitnr = 0; while (offset < end) { bit = !!le_test_bit(bitnr, bitmap); if (prev_bit == 0 && bit == 1) { extent_start = offset; } else if (prev_bit == 1 && bit == 0) { key.objectid = extent_start; key.type = BTRFS_FREE_SPACE_EXTENT_KEY; key.offset = offset - extent_start; ret = btrfs_insert_empty_item(trans, root, path, &key, 0); if (ret) goto out; btrfs_release_path(path); extent_count++; } prev_bit = bit; offset += fs_info->sectorsize; bitnr++; } if (prev_bit == 1) { key.objectid = extent_start; key.type = BTRFS_FREE_SPACE_EXTENT_KEY; key.offset = end - extent_start; ret = btrfs_insert_empty_item(trans, root, path, &key, 0); if (ret) goto out; btrfs_release_path(path); extent_count++; } if (extent_count != expected_extent_count) { btrfs_err(fs_info, "incorrect extent count for %llu; counted %u, expected %u", block_group->key.objectid, extent_count, expected_extent_count); ASSERT(0); ret = -EIO; goto out; } ret = 0; out: kvfree(bitmap); if (ret) btrfs_abort_transaction(trans, ret); return ret; } static int update_free_space_extent_count(struct btrfs_trans_handle *trans, struct btrfs_fs_info *fs_info, struct btrfs_block_group_cache *block_group, struct btrfs_path *path, int new_extents) { struct btrfs_free_space_info *info; u32 flags; u32 extent_count; int ret = 0; if (new_extents == 0) return 0; info = search_free_space_info(trans, fs_info, block_group, path, 1); if (IS_ERR(info)) { ret = PTR_ERR(info); goto out; } flags = btrfs_free_space_flags(path->nodes[0], info); extent_count = btrfs_free_space_extent_count(path->nodes[0], info); extent_count += new_extents; btrfs_set_free_space_extent_count(path->nodes[0], info, extent_count); btrfs_mark_buffer_dirty(path->nodes[0]); btrfs_release_path(path); if (!(flags & BTRFS_FREE_SPACE_USING_BITMAPS) && extent_count > block_group->bitmap_high_thresh) { ret = convert_free_space_to_bitmaps(trans, fs_info, block_group, path); } else if ((flags & BTRFS_FREE_SPACE_USING_BITMAPS) && extent_count < block_group->bitmap_low_thresh) { ret = convert_free_space_to_extents(trans, fs_info, block_group, path); } out: return ret; } int free_space_test_bit(struct btrfs_block_group_cache *block_group, struct btrfs_path *path, u64 offset) { struct extent_buffer *leaf; struct btrfs_key key; u64 found_start, found_end; unsigned long ptr, i; leaf = path->nodes[0]; btrfs_item_key_to_cpu(leaf, &key, path->slots[0]); ASSERT(key.type == BTRFS_FREE_SPACE_BITMAP_KEY); found_start = key.objectid; found_end = key.objectid + key.offset; ASSERT(offset >= found_start && offset < found_end); ptr = btrfs_item_ptr_offset(leaf, path->slots[0]); i = div_u64(offset - found_start, block_group->fs_info->sectorsize); return !!extent_buffer_test_bit(leaf, ptr, i); } static void free_space_set_bits(struct btrfs_block_group_cache *block_group, struct btrfs_path *path, u64 *start, u64 *size, int bit) { struct btrfs_fs_info *fs_info = block_group->fs_info; struct extent_buffer *leaf; struct btrfs_key key; u64 end = *start + *size; u64 found_start, found_end; unsigned long ptr, first, last; leaf = path->nodes[0]; btrfs_item_key_to_cpu(leaf, &key, path->slots[0]); ASSERT(key.type == BTRFS_FREE_SPACE_BITMAP_KEY); found_start = key.objectid; found_end = key.objectid + key.offset; ASSERT(*start >= found_start && *start < found_end); ASSERT(end > found_start); if (end > found_end) end = found_end; ptr = btrfs_item_ptr_offset(leaf, path->slots[0]); first = div_u64(*start - found_start, fs_info->sectorsize); last = div_u64(end - found_start, fs_info->sectorsize); if (bit) extent_buffer_bitmap_set(leaf, ptr, first, last - first); else extent_buffer_bitmap_clear(leaf, ptr, first, last - first); btrfs_mark_buffer_dirty(leaf); *size -= end - *start; *start = end; } /* * We can't use btrfs_next_item() in modify_free_space_bitmap() because * btrfs_next_leaf() doesn't get the path for writing. We can forgo the fancy * tree walking in btrfs_next_leaf() anyways because we know exactly what we're * looking for. */ static int free_space_next_bitmap(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct btrfs_path *p) { struct btrfs_key key; if (p->slots[0] + 1 < btrfs_header_nritems(p->nodes[0])) { p->slots[0]++; return 0; } btrfs_item_key_to_cpu(p->nodes[0], &key, p->slots[0]); btrfs_release_path(p); key.objectid += key.offset; key.type = (u8)-1; key.offset = (u64)-1; return btrfs_search_prev_slot(trans, root, &key, p, 0, 1); } /* * If remove is 1, then we are removing free space, thus clearing bits in the * bitmap. If remove is 0, then we are adding free space, thus setting bits in * the bitmap. */ static int modify_free_space_bitmap(struct btrfs_trans_handle *trans, struct btrfs_fs_info *fs_info, struct btrfs_block_group_cache *block_group, struct btrfs_path *path, u64 start, u64 size, int remove) { struct btrfs_root *root = fs_info->free_space_root; struct btrfs_key key; u64 end = start + size; u64 cur_start, cur_size; int prev_bit, next_bit; int new_extents; int ret; /* * Read the bit for the block immediately before the extent of space if * that block is within the block group. */ if (start > block_group->key.objectid) { u64 prev_block = start - block_group->fs_info->sectorsize; key.objectid = prev_block; key.type = (u8)-1; key.offset = (u64)-1; ret = btrfs_search_prev_slot(trans, root, &key, path, 0, 1); if (ret) goto out; prev_bit = free_space_test_bit(block_group, path, prev_block); /* The previous block may have been in the previous bitmap. */ btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]); if (start >= key.objectid + key.offset) { ret = free_space_next_bitmap(trans, root, path); if (ret) goto out; } } else { key.objectid = start; key.type = (u8)-1; key.offset = (u64)-1; ret = btrfs_search_prev_slot(trans, root, &key, path, 0, 1); if (ret) goto out; prev_bit = -1; } /* * Iterate over all of the bitmaps overlapped by the extent of space, * clearing/setting bits as required. */ cur_start = start; cur_size = size; while (1) { free_space_set_bits(block_group, path, &cur_start, &cur_size, !remove); if (cur_size == 0) break; ret = free_space_next_bitmap(trans, root, path); if (ret) goto out; } /* * Read the bit for the block immediately after the extent of space if * that block is within the block group. */ if (end < block_group->key.objectid + block_group->key.offset) { /* The next block may be in the next bitmap. */ btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]); if (end >= key.objectid + key.offset) { ret = free_space_next_bitmap(trans, root, path); if (ret) goto out; } next_bit = free_space_test_bit(block_group, path, end); } else { next_bit = -1; } if (remove) { new_extents = -1; if (prev_bit == 1) { /* Leftover on the left. */ new_extents++; } if (next_bit == 1) { /* Leftover on the right. */ new_extents++; } } else { new_extents = 1; if (prev_bit == 1) { /* Merging with neighbor on the left. */ new_extents--; } if (next_bit == 1) { /* Merging with neighbor on the right. */ new_extents--; } } btrfs_release_path(path); ret = update_free_space_extent_count(trans, fs_info, block_group, path, new_extents); out: return ret; } static int remove_free_space_extent(struct btrfs_trans_handle *trans, struct btrfs_fs_info *fs_info, struct btrfs_block_group_cache *block_group, struct btrfs_path *path, u64 start, u64 size) { struct btrfs_root *root = fs_info->free_space_root; struct btrfs_key key; u64 found_start, found_end; u64 end = start + size; int new_extents = -1; int ret; key.objectid = start; key.type = (u8)-1; key.offset = (u64)-1; ret = btrfs_search_prev_slot(trans, root, &key, path, -1, 1); if (ret) goto out; btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]); ASSERT(key.type == BTRFS_FREE_SPACE_EXTENT_KEY); found_start = key.objectid; found_end = key.objectid + key.offset; ASSERT(start >= found_start && end <= found_end); /* * Okay, now that we've found the free space extent which contains the * free space that we are removing, there are four cases: * * 1. We're using the whole extent: delete the key we found and * decrement the free space extent count. * 2. We are using part of the extent starting at the beginning: delete * the key we found and insert a new key representing the leftover at * the end. There is no net change in the number of extents. * 3. We are using part of the extent ending at the end: delete the key * we found and insert a new key representing the leftover at the * beginning. There is no net change in the number of extents. * 4. We are using part of the extent in the middle: delete the key we * found and insert two new keys representing the leftovers on each * side. Where we used to have one extent, we now have two, so increment * the extent count. We may need to convert the block group to bitmaps * as a result. */ /* Delete the existing key (cases 1-4). */ ret = btrfs_del_item(trans, root, path); if (ret) goto out; /* Add a key for leftovers at the beginning (cases 3 and 4). */ if (start > found_start) { key.objectid = found_start; key.type = BTRFS_FREE_SPACE_EXTENT_KEY; key.offset = start - found_start; btrfs_release_path(path); ret = btrfs_insert_empty_item(trans, root, path, &key, 0); if (ret) goto out; new_extents++; } /* Add a key for leftovers at the end (cases 2 and 4). */ if (end < found_end) { key.objectid = end; key.type = BTRFS_FREE_SPACE_EXTENT_KEY; key.offset = found_end - end; btrfs_release_path(path); ret = btrfs_insert_empty_item(trans, root, path, &key, 0); if (ret) goto out; new_extents++; } btrfs_release_path(path); ret = update_free_space_extent_count(trans, fs_info, block_group, path, new_extents); out: return ret; } int __remove_from_free_space_tree(struct btrfs_trans_handle *trans, struct btrfs_fs_info *fs_info, struct btrfs_block_group_cache *block_group, struct btrfs_path *path, u64 start, u64 size) { struct btrfs_free_space_info *info; u32 flags; int ret; if (block_group->needs_free_space) { ret = __add_block_group_free_space(trans, fs_info, block_group, path); if (ret) return ret; } info = search_free_space_info(NULL, fs_info, block_group, path, 0); if (IS_ERR(info)) return PTR_ERR(info); flags = btrfs_free_space_flags(path->nodes[0], info); btrfs_release_path(path); if (flags & BTRFS_FREE_SPACE_USING_BITMAPS) { return modify_free_space_bitmap(trans, fs_info, block_group, path, start, size, 1); } else { return remove_free_space_extent(trans, fs_info, block_group, path, start, size); } } int remove_from_free_space_tree(struct btrfs_trans_handle *trans, struct btrfs_fs_info *fs_info, u64 start, u64 size) { struct btrfs_block_group_cache *block_group; struct btrfs_path *path; int ret; if (!btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE)) return 0; path = btrfs_alloc_path(); if (!path) { ret = -ENOMEM; goto out; } block_group = btrfs_lookup_block_group(fs_info, start); if (!block_group) { ASSERT(0); ret = -ENOENT; goto out; } mutex_lock(&block_group->free_space_lock); ret = __remove_from_free_space_tree(trans, fs_info, block_group, path, start, size); mutex_unlock(&block_group->free_space_lock); btrfs_put_block_group(block_group); out: btrfs_free_path(path); if (ret) btrfs_abort_transaction(trans, ret); return ret; } static int add_free_space_extent(struct btrfs_trans_handle *trans, struct btrfs_fs_info *fs_info, struct btrfs_block_group_cache *block_group, struct btrfs_path *path, u64 start, u64 size) { struct btrfs_root *root = fs_info->free_space_root; struct btrfs_key key, new_key; u64 found_start, found_end; u64 end = start + size; int new_extents = 1; int ret; /* * We are adding a new extent of free space, but we need to merge * extents. There are four cases here: * * 1. The new extent does not have any immediate neighbors to merge * with: add the new key and increment the free space extent count. We * may need to convert the block group to bitmaps as a result. * 2. The new extent has an immediate neighbor before it: remove the * previous key and insert a new key combining both of them. There is no * net change in the number of extents. * 3. The new extent has an immediate neighbor after it: remove the next * key and insert a new key combining both of them. There is no net * change in the number of extents. * 4. The new extent has immediate neighbors on both sides: remove both * of the keys and insert a new key combining all of them. Where we used * to have two extents, we now have one, so decrement the extent count. */ new_key.objectid = start; new_key.type = BTRFS_FREE_SPACE_EXTENT_KEY; new_key.offset = size; /* Search for a neighbor on the left. */ if (start == block_group->key.objectid) goto right; key.objectid = start - 1; key.type = (u8)-1; key.offset = (u64)-1; ret = btrfs_search_prev_slot(trans, root, &key, path, -1, 1); if (ret) goto out; btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]); if (key.type != BTRFS_FREE_SPACE_EXTENT_KEY) { ASSERT(key.type == BTRFS_FREE_SPACE_INFO_KEY); btrfs_release_path(path); goto right; } found_start = key.objectid; found_end = key.objectid + key.offset; ASSERT(found_start >= block_group->key.objectid && found_end > block_group->key.objectid); ASSERT(found_start < start && found_end <= start); /* * Delete the neighbor on the left and absorb it into the new key (cases * 2 and 4). */ if (found_end == start) { ret = btrfs_del_item(trans, root, path); if (ret) goto out; new_key.objectid = found_start; new_key.offset += key.offset; new_extents--; } btrfs_release_path(path); right: /* Search for a neighbor on the right. */ if (end == block_group->key.objectid + block_group->key.offset) goto insert; key.objectid = end; key.type = (u8)-1; key.offset = (u64)-1; ret = btrfs_search_prev_slot(trans, root, &key, path, -1, 1); if (ret) goto out; btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]); if (key.type != BTRFS_FREE_SPACE_EXTENT_KEY) { ASSERT(key.type == BTRFS_FREE_SPACE_INFO_KEY); btrfs_release_path(path); goto insert; } found_start = key.objectid; found_end = key.objectid + key.offset; ASSERT(found_start >= block_group->key.objectid && found_end > block_group->key.objectid); ASSERT((found_start < start && found_end <= start) || (found_start >= end && found_end > end)); /* * Delete the neighbor on the right and absorb it into the new key * (cases 3 and 4). */ if (found_start == end) { ret = btrfs_del_item(trans, root, path); if (ret) goto out; new_key.offset += key.offset; new_extents--; } btrfs_release_path(path); insert: /* Insert the new key (cases 1-4). */ ret = btrfs_insert_empty_item(trans, root, path, &new_key, 0); if (ret) goto out; btrfs_release_path(path); ret = update_free_space_extent_count(trans, fs_info, block_group, path, new_extents); out: return ret; } int __add_to_free_space_tree(struct btrfs_trans_handle *trans, struct btrfs_fs_info *fs_info, struct btrfs_block_group_cache *block_group, struct btrfs_path *path, u64 start, u64 size) { struct btrfs_free_space_info *info; u32 flags; int ret; if (block_group->needs_free_space) { ret = __add_block_group_free_space(trans, fs_info, block_group, path); if (ret) return ret; } info = search_free_space_info(NULL, fs_info, block_group, path, 0); if (IS_ERR(info)) return PTR_ERR(info); flags = btrfs_free_space_flags(path->nodes[0], info); btrfs_release_path(path); if (flags & BTRFS_FREE_SPACE_USING_BITMAPS) { return modify_free_space_bitmap(trans, fs_info, block_group, path, start, size, 0); } else { return add_free_space_extent(trans, fs_info, block_group, path, start, size); } } int add_to_free_space_tree(struct btrfs_trans_handle *trans, struct btrfs_fs_info *fs_info, u64 start, u64 size) { struct btrfs_block_group_cache *block_group; struct btrfs_path *path; int ret; if (!btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE)) return 0; path = btrfs_alloc_path(); if (!path) { ret = -ENOMEM; goto out; } block_group = btrfs_lookup_block_group(fs_info, start); if (!block_group) { ASSERT(0); ret = -ENOENT; goto out; } mutex_lock(&block_group->free_space_lock); ret = __add_to_free_space_tree(trans, fs_info, block_group, path, start, size); mutex_unlock(&block_group->free_space_lock); btrfs_put_block_group(block_group); out: btrfs_free_path(path); if (ret) btrfs_abort_transaction(trans, ret); return ret; } /* * Populate the free space tree by walking the extent tree. Operations on the * extent tree that happen as a result of writes to the free space tree will go * through the normal add/remove hooks. */ static int populate_free_space_tree(struct btrfs_trans_handle *trans, struct btrfs_fs_info *fs_info, struct btrfs_block_group_cache *block_group) { struct btrfs_root *extent_root = fs_info->extent_root; struct btrfs_path *path, *path2; struct btrfs_key key; u64 start, end; int ret; path = btrfs_alloc_path(); if (!path) return -ENOMEM; path->reada = 1; path2 = btrfs_alloc_path(); if (!path2) { btrfs_free_path(path); return -ENOMEM; } ret = add_new_free_space_info(trans, fs_info, block_group, path2); if (ret) goto out; mutex_lock(&block_group->free_space_lock); /* * Iterate through all of the extent and metadata items in this block * group, adding the free space between them and the free space at the * end. Note that EXTENT_ITEM and METADATA_ITEM are less than * BLOCK_GROUP_ITEM, so an extent may precede the block group that it's * contained in. */ key.objectid = block_group->key.objectid; key.type = BTRFS_EXTENT_ITEM_KEY; key.offset = 0; ret = btrfs_search_slot_for_read(extent_root, &key, path, 1, 0); if (ret < 0) goto out_locked; ASSERT(ret == 0); start = block_group->key.objectid; end = block_group->key.objectid + block_group->key.offset; while (1) { btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]); if (key.type == BTRFS_EXTENT_ITEM_KEY || key.type == BTRFS_METADATA_ITEM_KEY) { if (key.objectid >= end) break; if (start < key.objectid) { ret = __add_to_free_space_tree(trans, fs_info, block_group, path2, start, key.objectid - start); if (ret) goto out_locked; } start = key.objectid; if (key.type == BTRFS_METADATA_ITEM_KEY) start += fs_info->nodesize; else start += key.offset; } else if (key.type == BTRFS_BLOCK_GROUP_ITEM_KEY) { if (key.objectid != block_group->key.objectid) break; } ret = btrfs_next_item(extent_root, path); if (ret < 0) goto out_locked; if (ret) break; } if (start < end) { ret = __add_to_free_space_tree(trans, fs_info, block_group, path2, start, end - start); if (ret) goto out_locked; } ret = 0; out_locked: mutex_unlock(&block_group->free_space_lock); out: btrfs_free_path(path2); btrfs_free_path(path); return ret; } int btrfs_create_free_space_tree(struct btrfs_fs_info *fs_info) { struct btrfs_trans_handle *trans; struct btrfs_root *tree_root = fs_info->tree_root; struct btrfs_root *free_space_root; struct btrfs_block_group_cache *block_group; struct rb_node *node; int ret; trans = btrfs_start_transaction(tree_root, 0); if (IS_ERR(trans)) return PTR_ERR(trans); set_bit(BTRFS_FS_CREATING_FREE_SPACE_TREE, &fs_info->flags); free_space_root = btrfs_create_tree(trans, fs_info, BTRFS_FREE_SPACE_TREE_OBJECTID); if (IS_ERR(free_space_root)) { ret = PTR_ERR(free_space_root); goto abort; } fs_info->free_space_root = free_space_root; node = rb_first(&fs_info->block_group_cache_tree); while (node) { block_group = rb_entry(node, struct btrfs_block_group_cache, cache_node); ret = populate_free_space_tree(trans, fs_info, block_group); if (ret) goto abort; node = rb_next(node); } btrfs_set_fs_compat_ro(fs_info, FREE_SPACE_TREE); btrfs_set_fs_compat_ro(fs_info, FREE_SPACE_TREE_VALID); clear_bit(BTRFS_FS_CREATING_FREE_SPACE_TREE, &fs_info->flags); ret = btrfs_commit_transaction(trans); if (ret) return ret; return 0; abort: clear_bit(BTRFS_FS_CREATING_FREE_SPACE_TREE, &fs_info->flags); btrfs_abort_transaction(trans, ret); btrfs_end_transaction(trans); return ret; } static int clear_free_space_tree(struct btrfs_trans_handle *trans, struct btrfs_root *root) { struct btrfs_path *path; struct btrfs_key key; int nr; int ret; path = btrfs_alloc_path(); if (!path) return -ENOMEM; path->leave_spinning = 1; key.objectid = 0; key.type = 0; key.offset = 0; while (1) { ret = btrfs_search_slot(trans, root, &key, path, -1, 1); if (ret < 0) goto out; nr = btrfs_header_nritems(path->nodes[0]); if (!nr) break; path->slots[0] = 0; ret = btrfs_del_items(trans, root, path, 0, nr); if (ret) goto out; btrfs_release_path(path); } ret = 0; out: btrfs_free_path(path); return ret; } int btrfs_clear_free_space_tree(struct btrfs_fs_info *fs_info) { struct btrfs_trans_handle *trans; struct btrfs_root *tree_root = fs_info->tree_root; struct btrfs_root *free_space_root = fs_info->free_space_root; int ret; trans = btrfs_start_transaction(tree_root, 0); if (IS_ERR(trans)) return PTR_ERR(trans); btrfs_clear_fs_compat_ro(fs_info, FREE_SPACE_TREE); btrfs_clear_fs_compat_ro(fs_info, FREE_SPACE_TREE_VALID); fs_info->free_space_root = NULL; ret = clear_free_space_tree(trans, free_space_root); if (ret) goto abort; ret = btrfs_del_root(trans, tree_root, &free_space_root->root_key); if (ret) goto abort; list_del(&free_space_root->dirty_list); btrfs_tree_lock(free_space_root->node); clean_tree_block(trans, fs_info, free_space_root->node); btrfs_tree_unlock(free_space_root->node); btrfs_free_tree_block(trans, free_space_root, free_space_root->node, 0, 1); free_extent_buffer(free_space_root->node); free_extent_buffer(free_space_root->commit_root); kfree(free_space_root); ret = btrfs_commit_transaction(trans); if (ret) return ret; return 0; abort: btrfs_abort_transaction(trans, ret); btrfs_end_transaction(trans); return ret; } static int __add_block_group_free_space(struct btrfs_trans_handle *trans, struct btrfs_fs_info *fs_info, struct btrfs_block_group_cache *block_group, struct btrfs_path *path) { u64 start, end; int ret; start = block_group->key.objectid; end = block_group->key.objectid + block_group->key.offset; block_group->needs_free_space = 0; ret = add_new_free_space_info(trans, fs_info, block_group, path); if (ret) return ret; return __add_to_free_space_tree(trans, fs_info, block_group, path, block_group->key.objectid, block_group->key.offset); } int add_block_group_free_space(struct btrfs_trans_handle *trans, struct btrfs_fs_info *fs_info, struct btrfs_block_group_cache *block_group) { struct btrfs_path *path = NULL; int ret = 0; if (!btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE)) return 0; mutex_lock(&block_group->free_space_lock); if (!block_group->needs_free_space) goto out; path = btrfs_alloc_path(); if (!path) { ret = -ENOMEM; goto out; } ret = __add_block_group_free_space(trans, fs_info, block_group, path); out: btrfs_free_path(path); mutex_unlock(&block_group->free_space_lock); if (ret) btrfs_abort_transaction(trans, ret); return ret; } int remove_block_group_free_space(struct btrfs_trans_handle *trans, struct btrfs_fs_info *fs_info, struct btrfs_block_group_cache *block_group) { struct btrfs_root *root = fs_info->free_space_root; struct btrfs_path *path; struct btrfs_key key, found_key; struct extent_buffer *leaf; u64 start, end; int done = 0, nr; int ret; if (!btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE)) return 0; if (block_group->needs_free_space) { /* We never added this block group to the free space tree. */ return 0; } path = btrfs_alloc_path(); if (!path) { ret = -ENOMEM; goto out; } start = block_group->key.objectid; end = block_group->key.objectid + block_group->key.offset; key.objectid = end - 1; key.type = (u8)-1; key.offset = (u64)-1; while (!done) { ret = btrfs_search_prev_slot(trans, root, &key, path, -1, 1); if (ret) goto out; leaf = path->nodes[0]; nr = 0; path->slots[0]++; while (path->slots[0] > 0) { btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0] - 1); if (found_key.type == BTRFS_FREE_SPACE_INFO_KEY) { ASSERT(found_key.objectid == block_group->key.objectid); ASSERT(found_key.offset == block_group->key.offset); done = 1; nr++; path->slots[0]--; break; } else if (found_key.type == BTRFS_FREE_SPACE_EXTENT_KEY || found_key.type == BTRFS_FREE_SPACE_BITMAP_KEY) { ASSERT(found_key.objectid >= start); ASSERT(found_key.objectid < end); ASSERT(found_key.objectid + found_key.offset <= end); nr++; path->slots[0]--; } else { ASSERT(0); } } ret = btrfs_del_items(trans, root, path, path->slots[0], nr); if (ret) goto out; btrfs_release_path(path); } ret = 0; out: btrfs_free_path(path); if (ret) btrfs_abort_transaction(trans, ret); return ret; } static int load_free_space_bitmaps(struct btrfs_caching_control *caching_ctl, struct btrfs_path *path, u32 expected_extent_count) { struct btrfs_block_group_cache *block_group; struct btrfs_fs_info *fs_info; struct btrfs_root *root; struct btrfs_key key; int prev_bit = 0, bit; /* Initialize to silence GCC. */ u64 extent_start = 0; u64 end, offset; u64 total_found = 0; u32 extent_count = 0; int ret; block_group = caching_ctl->block_group; fs_info = block_group->fs_info; root = fs_info->free_space_root; end = block_group->key.objectid + block_group->key.offset; while (1) { ret = btrfs_next_item(root, path); if (ret < 0) goto out; if (ret) break; btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]); if (key.type == BTRFS_FREE_SPACE_INFO_KEY) break; ASSERT(key.type == BTRFS_FREE_SPACE_BITMAP_KEY); ASSERT(key.objectid < end && key.objectid + key.offset <= end); caching_ctl->progress = key.objectid; offset = key.objectid; while (offset < key.objectid + key.offset) { bit = free_space_test_bit(block_group, path, offset); if (prev_bit == 0 && bit == 1) { extent_start = offset; } else if (prev_bit == 1 && bit == 0) { total_found += add_new_free_space(block_group, fs_info, extent_start, offset); if (total_found > CACHING_CTL_WAKE_UP) { total_found = 0; wake_up(&caching_ctl->wait); } extent_count++; } prev_bit = bit; offset += fs_info->sectorsize; } } if (prev_bit == 1) { total_found += add_new_free_space(block_group, fs_info, extent_start, end); extent_count++; } if (extent_count != expected_extent_count) { btrfs_err(fs_info, "incorrect extent count for %llu; counted %u, expected %u", block_group->key.objectid, extent_count, expected_extent_count); ASSERT(0); ret = -EIO; goto out; } caching_ctl->progress = (u64)-1; ret = 0; out: return ret; } static int load_free_space_extents(struct btrfs_caching_control *caching_ctl, struct btrfs_path *path, u32 expected_extent_count) { struct btrfs_block_group_cache *block_group; struct btrfs_fs_info *fs_info; struct btrfs_root *root; struct btrfs_key key; u64 end; u64 total_found = 0; u32 extent_count = 0; int ret; block_group = caching_ctl->block_group; fs_info = block_group->fs_info; root = fs_info->free_space_root; end = block_group->key.objectid + block_group->key.offset; while (1) { ret = btrfs_next_item(root, path); if (ret < 0) goto out; if (ret) break; btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]); if (key.type == BTRFS_FREE_SPACE_INFO_KEY) break; ASSERT(key.type == BTRFS_FREE_SPACE_EXTENT_KEY); ASSERT(key.objectid < end && key.objectid + key.offset <= end); caching_ctl->progress = key.objectid; total_found += add_new_free_space(block_group, fs_info, key.objectid, key.objectid + key.offset); if (total_found > CACHING_CTL_WAKE_UP) { total_found = 0; wake_up(&caching_ctl->wait); } extent_count++; } if (extent_count != expected_extent_count) { btrfs_err(fs_info, "incorrect extent count for %llu; counted %u, expected %u", block_group->key.objectid, extent_count, expected_extent_count); ASSERT(0); ret = -EIO; goto out; } caching_ctl->progress = (u64)-1; ret = 0; out: return ret; } int load_free_space_tree(struct btrfs_caching_control *caching_ctl) { struct btrfs_block_group_cache *block_group; struct btrfs_fs_info *fs_info; struct btrfs_free_space_info *info; struct btrfs_path *path; u32 extent_count, flags; int ret; block_group = caching_ctl->block_group; fs_info = block_group->fs_info; path = btrfs_alloc_path(); if (!path) return -ENOMEM; /* * Just like caching_thread() doesn't want to deadlock on the extent * tree, we don't want to deadlock on the free space tree. */ path->skip_locking = 1; path->search_commit_root = 1; path->reada = 1; info = search_free_space_info(NULL, fs_info, block_group, path, 0); if (IS_ERR(info)) { ret = PTR_ERR(info); goto out; } extent_count = btrfs_free_space_extent_count(path->nodes[0], info); flags = btrfs_free_space_flags(path->nodes[0], info); /* * We left path pointing to the free space info item, so now * load_free_space_foo can just iterate through the free space tree from * there. */ if (flags & BTRFS_FREE_SPACE_USING_BITMAPS) ret = load_free_space_bitmaps(caching_ctl, path, extent_count); else ret = load_free_space_extents(caching_ctl, path, extent_count); out: btrfs_free_path(path); return ret; }