ASR_BASE
Change-Id: Icf3719cc0afe3eeb3edc7fa80a2eb5199ca9dda1
diff --git a/marvell/linux/fs/btrfs/free-space-tree.c b/marvell/linux/fs/btrfs/free-space-tree.c
new file mode 100644
index 0000000..dfabbbf
--- /dev/null
+++ b/marvell/linux/fs/btrfs/free-space-tree.c
@@ -0,0 +1,1584 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2015 Facebook. All rights reserved.
+ */
+
+#include <linux/kernel.h>
+#include <linux/sched/mm.h>
+#include "ctree.h"
+#include "disk-io.h"
+#include "locking.h"
+#include "free-space-tree.h"
+#include "transaction.h"
+#include "block-group.h"
+
+static int __add_block_group_free_space(struct btrfs_trans_handle *trans,
+ 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_block_group_cache *block_group,
+ struct btrfs_path *path)
+{
+ struct btrfs_root *root = trans->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;
+}
+
+EXPORT_FOR_TESTS
+struct btrfs_free_space_info *search_free_space_info(
+ struct btrfs_trans_handle *trans,
+ struct btrfs_block_group_cache *block_group,
+ struct btrfs_path *path, int cow)
+{
+ struct btrfs_fs_info *fs_info = block_group->fs_info;
+ 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 unsigned long *alloc_bitmap(u32 bitmap_size)
+{
+ unsigned long *ret;
+ unsigned int nofs_flag;
+ u32 bitmap_rounded_size = round_up(bitmap_size, sizeof(unsigned long));
+
+ /*
+ * GFP_NOFS doesn't work with kvmalloc(), but we really can't recurse
+ * into the filesystem as the free space bitmap can be modified in the
+ * critical section of a transaction commit.
+ *
+ * TODO: push the memalloc_nofs_{save,restore}() to the caller where we
+ * know that recursion is unsafe.
+ */
+ nofs_flag = memalloc_nofs_save();
+ ret = kvzalloc(bitmap_rounded_size, GFP_KERNEL);
+ memalloc_nofs_restore(nofs_flag);
+ return ret;
+}
+
+static void le_bitmap_set(unsigned long *map, unsigned int start, int len)
+{
+ u8 *p = ((u8 *)map) + BIT_BYTE(start);
+ const unsigned int size = start + len;
+ int bits_to_set = BITS_PER_BYTE - (start % BITS_PER_BYTE);
+ u8 mask_to_set = BITMAP_FIRST_BYTE_MASK(start);
+
+ while (len - bits_to_set >= 0) {
+ *p |= mask_to_set;
+ len -= bits_to_set;
+ bits_to_set = BITS_PER_BYTE;
+ mask_to_set = ~0;
+ p++;
+ }
+ if (len) {
+ mask_to_set &= BITMAP_LAST_BYTE_MASK(size);
+ *p |= mask_to_set;
+ }
+}
+
+EXPORT_FOR_TESTS
+int convert_free_space_to_bitmaps(struct btrfs_trans_handle *trans,
+ struct btrfs_block_group_cache *block_group,
+ struct btrfs_path *path)
+{
+ struct btrfs_fs_info *fs_info = trans->fs_info;
+ 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;
+ unsigned long *bitmap;
+ char *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, 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 = (char *)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;
+}
+
+EXPORT_FOR_TESTS
+int convert_free_space_to_extents(struct btrfs_trans_handle *trans,
+ struct btrfs_block_group_cache *block_group,
+ struct btrfs_path *path)
+{
+ struct btrfs_fs_info *fs_info = trans->fs_info;
+ 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;
+ unsigned long *bitmap;
+ u64 start, end;
+ u32 bitmap_size, flags, expected_extent_count;
+ unsigned long nrbits, start_bit, end_bit;
+ 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;
+ char *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 = ((char *)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, 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);
+
+ nrbits = div_u64(block_group->key.offset, block_group->fs_info->sectorsize);
+ start_bit = find_next_bit_le(bitmap, nrbits, 0);
+
+ while (start_bit < nrbits) {
+ end_bit = find_next_zero_bit_le(bitmap, nrbits, start_bit);
+ ASSERT(start_bit < end_bit);
+
+ key.objectid = start + start_bit * block_group->fs_info->sectorsize;
+ key.type = BTRFS_FREE_SPACE_EXTENT_KEY;
+ key.offset = (end_bit - start_bit) * block_group->fs_info->sectorsize;
+
+ ret = btrfs_insert_empty_item(trans, root, path, &key, 0);
+ if (ret)
+ goto out;
+ btrfs_release_path(path);
+
+ extent_count++;
+
+ start_bit = find_next_bit_le(bitmap, nrbits, end_bit);
+ }
+
+ 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_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, 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, 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, block_group, path);
+ }
+
+out:
+ return ret;
+}
+
+EXPORT_FOR_TESTS
+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_block_group_cache *block_group,
+ struct btrfs_path *path,
+ u64 start, u64 size, int remove)
+{
+ struct btrfs_root *root = block_group->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, block_group, path,
+ new_extents);
+
+out:
+ return ret;
+}
+
+static int remove_free_space_extent(struct btrfs_trans_handle *trans,
+ struct btrfs_block_group_cache *block_group,
+ struct btrfs_path *path,
+ u64 start, u64 size)
+{
+ struct btrfs_root *root = trans->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, block_group, path,
+ new_extents);
+
+out:
+ return ret;
+}
+
+EXPORT_FOR_TESTS
+int __remove_from_free_space_tree(struct btrfs_trans_handle *trans,
+ 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, block_group, path);
+ if (ret)
+ return ret;
+ }
+
+ info = search_free_space_info(NULL, 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, block_group, path,
+ start, size, 1);
+ } else {
+ return remove_free_space_extent(trans, block_group, path,
+ start, size);
+ }
+}
+
+int remove_from_free_space_tree(struct btrfs_trans_handle *trans,
+ u64 start, u64 size)
+{
+ struct btrfs_block_group_cache *block_group;
+ struct btrfs_path *path;
+ int ret;
+
+ if (!btrfs_fs_compat_ro(trans->fs_info, FREE_SPACE_TREE))
+ return 0;
+
+ path = btrfs_alloc_path();
+ if (!path) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ block_group = btrfs_lookup_block_group(trans->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, 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_block_group_cache *block_group,
+ struct btrfs_path *path,
+ u64 start, u64 size)
+{
+ struct btrfs_root *root = trans->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, block_group, path,
+ new_extents);
+
+out:
+ return ret;
+}
+
+EXPORT_FOR_TESTS
+int __add_to_free_space_tree(struct btrfs_trans_handle *trans,
+ 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, block_group, path);
+ if (ret)
+ return ret;
+ }
+
+ info = search_free_space_info(NULL, 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, block_group, path,
+ start, size, 0);
+ } else {
+ return add_free_space_extent(trans, block_group, path, start,
+ size);
+ }
+}
+
+int add_to_free_space_tree(struct btrfs_trans_handle *trans,
+ u64 start, u64 size)
+{
+ struct btrfs_block_group_cache *block_group;
+ struct btrfs_path *path;
+ int ret;
+
+ if (!btrfs_fs_compat_ro(trans->fs_info, FREE_SPACE_TREE))
+ return 0;
+
+ path = btrfs_alloc_path();
+ if (!path) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ block_group = btrfs_lookup_block_group(trans->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, 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_block_group_cache *block_group)
+{
+ struct btrfs_root *extent_root = trans->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 = READA_FORWARD;
+
+ path2 = btrfs_alloc_path();
+ if (!path2) {
+ btrfs_free_path(path);
+ return -ENOMEM;
+ }
+
+ ret = add_new_free_space_info(trans, 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,
+ block_group,
+ path2, start,
+ key.objectid -
+ start);
+ if (ret)
+ goto out_locked;
+ }
+ start = key.objectid;
+ if (key.type == BTRFS_METADATA_ITEM_KEY)
+ start += trans->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, 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);
+ set_bit(BTRFS_FS_FREE_SPACE_TREE_UNTRUSTED, &fs_info->flags);
+ free_space_root = btrfs_create_tree(trans,
+ 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, 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);
+
+ /*
+ * Now that we've committed the transaction any reading of our commit
+ * root will be safe, so we can cache from the free space tree now.
+ */
+ clear_bit(BTRFS_FS_FREE_SPACE_TREE_UNTRUSTED, &fs_info->flags);
+ return ret;
+
+abort:
+ clear_bit(BTRFS_FS_CREATING_FREE_SPACE_TREE, &fs_info->flags);
+ clear_bit(BTRFS_FS_FREE_SPACE_TREE_UNTRUSTED, &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, &free_space_root->root_key);
+ if (ret)
+ goto abort;
+
+ list_del(&free_space_root->dirty_list);
+
+ btrfs_tree_lock(free_space_root->node);
+ btrfs_clean_tree_block(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);
+
+ return btrfs_commit_transaction(trans);
+
+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_block_group_cache *block_group,
+ struct btrfs_path *path)
+{
+ int ret;
+
+ block_group->needs_free_space = 0;
+
+ ret = add_new_free_space_info(trans, block_group, path);
+ if (ret)
+ return ret;
+
+ return __add_to_free_space_tree(trans, block_group, path,
+ block_group->key.objectid,
+ block_group->key.offset);
+}
+
+int add_block_group_free_space(struct btrfs_trans_handle *trans,
+ struct btrfs_block_group_cache *block_group)
+{
+ struct btrfs_fs_info *fs_info = trans->fs_info;
+ 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, 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_block_group_cache *block_group)
+{
+ struct btrfs_root *root = trans->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(trans->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,
+ 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, 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, 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_free_space_info *info;
+ struct btrfs_path *path;
+ u32 extent_count, flags;
+ int ret;
+
+ block_group = caching_ctl->block_group;
+
+ 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 = READA_FORWARD;
+
+ info = search_free_space_info(NULL, 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;
+}