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From: Omar Sandoval <osandov@osandov.com>
To: Nikolay Borisov <nborisov@suse.com>
Cc: linux-btrfs@vger.kernel.org
Subject: Re: [PATCH 05/10] btrfs-progs: Pull free space tree related code from kernel
Date: Thu, 4 Oct 2018 11:26:36 -0700	[thread overview]
Message-ID: <20181004182636.GE25437@vader> (raw)
In-Reply-To: <1538405181-25231-6-git-send-email-nborisov@suse.com>

On Mon, Oct 01, 2018 at 05:46:16PM +0300, Nikolay Borisov wrote:
> To help implement free space tree checker in user space some kernel
> function are necessary, namely iterating/deleting/adding freespace
> items, some internal search functions. Functions to populate a block
> group based on the extent tree. The code is largely copy/paste from
> the kernel with locking eliminated (i.e free_space_lock). It supports
> reading/writing of both bitmap and extent based FST trees.

For some reason, a lot of this added code uses spaces instead of tabs,
so I had to fix that in order to compare it to the kernel code (some of
the functions were reordered, too).

The only functional difference I noticed was that this is missing the
code to insert the block group header in the free space tree:

	if (block_group->needs_free_space) {
		ret = __add_block_group_free_space(trans, block_group, path);
		if (ret)
			return ret;
	}

Was that intentionally omitted? Without it, the free space tree is
pretty broken :(

> Signed-off-by: Nikolay Borisov <nborisov@suse.com>
> ---
>  ctree.c           |   77 ++++
>  ctree.h           |   15 +
>  free-space-tree.c | 1253 ++++++++++++++++++++++++++++++++++++++++++++++++++++-
>  free-space-tree.h |   13 +-
>  kerncompat.h      |    6 +
>  5 files changed, 1357 insertions(+), 7 deletions(-)
> 
> diff --git a/ctree.c b/ctree.c
> index d8a6883aa85f..aa1568620205 100644
> --- a/ctree.c
> +++ b/ctree.c
> @@ -1226,6 +1226,83 @@ int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root
>  }
>  
>  /*
> + * helper to use instead of search slot if no exact match is needed but
> + * instead the next or previous item should be returned.
> + * When find_higher is true, the next higher item is returned, the next lower
> + * otherwise.
> + * When return_any and find_higher are both true, and no higher item is found,
> + * return the next lower instead.
> + * When return_any is true and find_higher is false, and no lower item is found,
> + * return the next higher instead.
> + * It returns 0 if any item is found, 1 if none is found (tree empty), and
> + * < 0 on error
> + */
> +int btrfs_search_slot_for_read(struct btrfs_root *root,
> +                               const struct btrfs_key *key,
> +                               struct btrfs_path *p, int find_higher,
> +                               int return_any)
> +{
> +        int ret;
> +        struct extent_buffer *leaf;
> +
> +again:
> +        ret = btrfs_search_slot(NULL, root, key, p, 0, 0);
> +        if (ret <= 0)
> +                return ret;
> +        /*
> +         * a return value of 1 means the path is at the position where the
> +         * item should be inserted. Normally this is the next bigger item,
> +         * but in case the previous item is the last in a leaf, path points
> +         * to the first free slot in the previous leaf, i.e. at an invalid
> +         * item.
> +         */
> +        leaf = p->nodes[0];
> +
> +        if (find_higher) {
> +                if (p->slots[0] >= btrfs_header_nritems(leaf)) {
> +                        ret = btrfs_next_leaf(root, p);
> +                        if (ret <= 0)
> +                                return ret;
> +                        if (!return_any)
> +                                return 1;
> +                        /*
> +                         * no higher item found, return the next
> +                         * lower instead
> +                         */
> +                        return_any = 0;
> +                        find_higher = 0;
> +                        btrfs_release_path(p);
> +                        goto again;
> +                }
> +        } else {
> +                if (p->slots[0] == 0) {
> +                        ret = btrfs_prev_leaf(root, p);
> +                        if (ret < 0)
> +                                return ret;
> +                        if (!ret) {
> +                                leaf = p->nodes[0];
> +                                if (p->slots[0] == btrfs_header_nritems(leaf))
> +                                        p->slots[0]--;
> +                                return 0;
> +                        }
> +                        if (!return_any)
> +                                return 1;
> +                        /*
> +                         * no lower item found, return the next
> +                         * higher instead
> +                         */
> +                        return_any = 0;
> +                        find_higher = 1;
> +                        btrfs_release_path(p);
> +                        goto again;
> +                } else {
> +                        --p->slots[0];
> +                }
> +        }
> +        return 0;
> +}
> +
> +/*
>   * adjust the pointers going up the tree, starting at level
>   * making sure the right key of each node is points to 'key'.
>   * This is used after shifting pointers to the left, so it stops
> diff --git a/ctree.h b/ctree.h
> index 49f0f5181512..a6d6c3decd87 100644
> --- a/ctree.h
> +++ b/ctree.h
> @@ -1071,6 +1071,17 @@ struct btrfs_block_group_cache {
>  	u64 flags;
>  	int cached;
>  	int ro;
> +	/*
> +         * If the free space extent count exceeds this number, convert the block
> +         * group to bitmaps.
> +         */
> +        u32 bitmap_high_thresh;
> +        /*
> +         * If the free space extent count drops below this number, convert the
> +         * block group back to extents.
> +         */
> +        u32 bitmap_low_thresh;
> +
>  };
>  
>  struct btrfs_device;
> @@ -2596,6 +2607,10 @@ int btrfs_split_item(struct btrfs_trans_handle *trans,
>  int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root
>  		      *root, struct btrfs_key *key, struct btrfs_path *p, int
>  		      ins_len, int cow);
> +int btrfs_search_slot_for_read(struct btrfs_root *root,
> +                               const struct btrfs_key *key,
> +                               struct btrfs_path *p, int find_higher,
> +                               int return_any);
>  int btrfs_find_item(struct btrfs_root *fs_root, struct btrfs_path *found_path,
>  		u64 iobjectid, u64 ioff, u8 key_type,
>  		struct btrfs_key *found_key);
> diff --git a/free-space-tree.c b/free-space-tree.c
> index b439b6b43146..3b7e8a3fe4f5 100644
> --- a/free-space-tree.c
> +++ b/free-space-tree.c
> @@ -21,6 +21,37 @@
>  #include "free-space-cache.h"
>  #include "free-space-tree.h"
>  #include "transaction.h"
> +#include "bitops.h"
> +#include "internal.h"
> +
> +void set_free_space_tree_thresholds(struct btrfs_block_group_cache *cache,
> +				    u64 sectorsize)
> +{
> +	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 = 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 struct btrfs_free_space_info *
>  search_free_space_info(struct btrfs_trans_handle *trans,
> @@ -47,8 +78,7 @@ search_free_space_info(struct btrfs_trans_handle *trans,
>  }
>  
>  static int free_space_test_bit(struct btrfs_block_group_cache *block_group,
> -			       struct btrfs_path *path, u64 offset,
> -			       u64 sectorsize)
> +			       struct btrfs_path *path, u64 offset)
>  {
>  	struct extent_buffer *leaf;
>  	struct btrfs_key key;
> @@ -64,10 +94,1085 @@ static int free_space_test_bit(struct btrfs_block_group_cache *block_group,
>  	ASSERT(offset >= found_start && offset < found_end);
>  
>  	ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
> -	i = (offset - found_start) / sectorsize;
> +	i = (offset - found_start) / leaf->fs_info->sectorsize;
>  	return !!extent_buffer_test_bit(leaf, ptr, i);
>  }
>  
> +/*
> + * 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 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;
> +}
> +
> +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;
> +	}
> +}
> +
> +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, 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) {
> +		fprintf(stderr,
> +			"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;
> +}
> +
> +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, 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);
> +
> +	nrbits = div_u64(block_group->key.offset, 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 * fs_info->sectorsize;
> +		key.type = BTRFS_FREE_SPACE_EXTENT_KEY;
> +		key.offset = (end_bit - start_bit) * 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) {
> +		fprintf(stderr,
> +			"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, 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, 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;
> +}
> +
> +
> +static void free_space_set_bits(struct btrfs_block_group_cache *block_group,
> +                                struct btrfs_path *path, u64 *start, u64 *size,
> +                                int bit)
> +{
> +        struct extent_buffer *leaf = path->nodes[0];
> +        struct btrfs_fs_info *fs_info = leaf->fs_info;
> +        struct btrfs_key key;
> +        u64 end = *start + *size;
> +        u64 found_start, found_end;
> +        unsigned long ptr, first, last;
> +
> +        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 = (*start - found_start) / fs_info->sectorsize;
> +        last = (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 = trans->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 - trans->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;
> +}
> +
> +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;
> +
> +	info = search_free_space_info(NULL, trans->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, 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;
> +	}
> +
> +	ret = __remove_from_free_space_tree(trans, block_group, path, start,
> +					    size);
> +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;
> +}
> +
> +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_fs_info *fs_info = trans->fs_info;
> +	struct btrfs_free_space_info *info;
> +	u32 flags;
> +
> +	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, 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;
> +	}
> +
> +	ret = __add_to_free_space_tree(trans, block_group, path, start, size);
> +out:
> +	btrfs_free_path(path);
> +	if (ret)
> +		btrfs_abort_transaction(trans, ret);
> +	return ret;
> +}
> +
> +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;
> +
> +        /*
> +         * 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;
> +        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;
> +                        }
> +                        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;
> +                if (ret)
> +                        break;
> +        }
> +        if (start < end) {
> +                ret = __add_to_free_space_tree(trans, block_group, path2,
> +                                               start, end - start);
> +                if (ret)
> +                        goto out;
> +        }
> +
> +        ret = 0;
> +out:
> +        btrfs_free_path(path2);
> +        btrfs_free_path(path);
> +        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;
> +
> +	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 clear_free_space_tree(struct btrfs_trans_handle *trans,
>  				 struct btrfs_root *root)
>  {
> @@ -204,8 +1309,8 @@ static int load_free_space_bitmaps(struct btrfs_fs_info *fs_info,
>  
>  		offset = key.objectid;
>  		while (offset < key.objectid + key.offset) {
> -			bit = free_space_test_bit(block_group, path, offset,
> -						  fs_info->sectorsize);
> +			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) {
> @@ -320,6 +1425,142 @@ static int load_free_space_extents(struct btrfs_fs_info *fs_info,
>  	return ret;
>  }
>  
> +struct btrfs_root *btrfs_create_tree(struct btrfs_trans_handle *trans,
> +                                     struct btrfs_fs_info *fs_info,
> +                                     u64 objectid)
> +{
> +	struct extent_buffer *leaf;
> +	struct btrfs_root *tree_root = fs_info->tree_root;
> +	struct btrfs_root *root;
> +	struct btrfs_key key;
> +	int ret = 0;
> +
> +	root = kzalloc(sizeof(*root), GFP_KERNEL);
> +	if (!root)
> +		return ERR_PTR(-ENOMEM);
> +
> +	btrfs_setup_root(root, fs_info, objectid);
> +	root->root_key.objectid = objectid;
> +	root->root_key.type = BTRFS_ROOT_ITEM_KEY;
> +	root->root_key.offset = 0;
> +
> +	leaf = btrfs_alloc_free_block(trans, root, fs_info->nodesize, objectid, NULL, 0, 0, 0);
> +	if (IS_ERR(leaf)) {
> +		ret = PTR_ERR(leaf);
> +		leaf = NULL;
> +		goto fail;
> +	}
> +
> +	memset_extent_buffer(leaf, 0, 0, sizeof(struct btrfs_header));
> +	btrfs_set_header_bytenr(leaf, leaf->start);
> +	btrfs_set_header_generation(leaf, trans->transid);
> +	btrfs_set_header_backref_rev(leaf, BTRFS_MIXED_BACKREF_REV);
> +	btrfs_set_header_owner(leaf, objectid);
> +	root->node = leaf;
> +	write_extent_buffer(leaf, fs_info->fsid, btrfs_header_fsid(), BTRFS_FSID_SIZE);
> +	write_extent_buffer(leaf, fs_info->chunk_tree_uuid,
> +			    btrfs_header_chunk_tree_uuid(leaf),
> +			    BTRFS_UUID_SIZE);
> +	btrfs_mark_buffer_dirty(leaf);
> +
> +	extent_buffer_get(root->node);
> +	root->commit_root = root->node;
> +	root->track_dirty = 1;
> +
> +	root->root_item.flags = 0;
> +	root->root_item.byte_limit = 0;
> +	btrfs_set_root_bytenr(&root->root_item, leaf->start);
> +	btrfs_set_root_generation(&root->root_item, trans->transid);
> +	btrfs_set_root_level(&root->root_item, 0);
> +	btrfs_set_root_refs(&root->root_item, 1);
> +	btrfs_set_root_used(&root->root_item, leaf->len);
> +	btrfs_set_root_last_snapshot(&root->root_item, 0);
> +	btrfs_set_root_dirid(&root->root_item, 0);
> +	memset(root->root_item.uuid, 0, BTRFS_UUID_SIZE);
> +	root->root_item.drop_level = 0;
> +
> +	key.objectid = objectid;
> +	key.type = BTRFS_ROOT_ITEM_KEY;
> +	key.offset = 0;
> +	ret = btrfs_insert_root(trans, tree_root, &key, &root->root_item);
> +	if (ret)
> +		goto fail;
> +
> +	return root;
> +
> +fail:
> +	if (leaf)
> +		free_extent_buffer(leaf);
> +
> +	kfree(root);
> +	return ERR_PTR(ret);
> +}
> +
> +#define btrfs_set_fs_compat_ro(__fs_info, opt) \
> +        __btrfs_set_fs_compat_ro((__fs_info), BTRFS_FEATURE_COMPAT_RO_##opt)
> +
> +static inline void __btrfs_set_fs_compat_ro(struct btrfs_fs_info *fs_info,
> +                                            u64 flag)
> +{
> +	struct btrfs_super_block *disk_super;
> +	u64 features;
> +
> +	disk_super = fs_info->super_copy;
> +	features = btrfs_super_compat_ro_flags(disk_super);
> +	if (!(features & flag)) {
> +		features = btrfs_super_compat_ro_flags(disk_super);
> +		if (!(features & flag)) {
> +			features |= flag;
> +			btrfs_set_super_compat_ro_flags(disk_super, features);
> +		}
> +	}
> +}
> +
> +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;
> +	u64 start = BTRFS_SUPER_INFO_OFFSET + BTRFS_SUPER_INFO_SIZE;
> +	int ret;
> +
> +	trans = btrfs_start_transaction(tree_root, 0);
> +	if (IS_ERR(trans))
> +		return PTR_ERR(trans);
> +
> +	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;
> +
> +	do {
> +		block_group = btrfs_lookup_first_block_group(fs_info, start);
> +		if (!block_group)
> +			break;
> +		start = block_group->key.objectid + block_group->key.offset;
> +		ret = populate_free_space_tree(trans, block_group);
> +		if (ret)
> +			goto abort;
> +	} while (block_group);
> +
> +	btrfs_set_fs_compat_ro(fs_info, FREE_SPACE_TREE);
> +	btrfs_set_fs_compat_ro(fs_info, FREE_SPACE_TREE_VALID);
> +
> +	ret = btrfs_commit_transaction(trans, tree_root);
> +	if (ret)
> +		return ret;
> +
> +	return 0;
> +
> +abort:
> +	btrfs_abort_transaction(trans, ret);
> +	return ret;
> +}
> +
>  int load_free_space_tree(struct btrfs_fs_info *fs_info,
>  			 struct btrfs_block_group_cache *block_group)
>  {
> @@ -332,7 +1573,7 @@ int load_free_space_tree(struct btrfs_fs_info *fs_info,
>  	path = btrfs_alloc_path();
>  	if (!path)
>  		return -ENOMEM;
> -	path->reada = 1;
> +	path->reada = READA_BACK;
>  
>  	info = search_free_space_info(NULL, fs_info, block_group, path, 0);
>  	if (IS_ERR(info)) {
> diff --git a/free-space-tree.h b/free-space-tree.h
> index 4845f13e6808..9530c2882358 100644
> --- a/free-space-tree.h
> +++ b/free-space-tree.h
> @@ -19,8 +19,19 @@
>  #ifndef __BTRFS_FREE_SPACE_TREE_H__
>  #define __BTRFS_FREE_SPACE_TREE_H__
>  
> +#define BTRFS_FREE_SPACE_BITMAP_SIZE 256
> +#define BTRFS_FREE_SPACE_BITMAP_BITS (BTRFS_FREE_SPACE_BITMAP_SIZE * BITS_PER_BYTE)
> +
>  int btrfs_clear_free_space_tree(struct btrfs_fs_info *fs_info);
>  int load_free_space_tree(struct btrfs_fs_info *fs_info,
>  			 struct btrfs_block_group_cache *block_group);
> -
> +int populate_free_space_tree(struct btrfs_trans_handle *trans,
> +			     struct btrfs_block_group_cache *block_group);
> +int remove_block_group_free_space(struct btrfs_trans_handle *trans,
> +				  struct btrfs_block_group_cache *block_group);
> +int add_to_free_space_tree(struct btrfs_trans_handle *trans, u64 start,
> +			   u64 size);
> +int remove_from_free_space_tree(struct btrfs_trans_handle *trans, u64 start,
> +				u64 size);
> +int btrfs_create_free_space_tree(struct btrfs_fs_info *info);
>  #endif
> diff --git a/kerncompat.h b/kerncompat.h
> index 1a2bc18c3ac2..a223a7f009bd 100644
> --- a/kerncompat.h
> +++ b/kerncompat.h
> @@ -263,6 +263,8 @@ static inline int IS_ERR_OR_NULL(const void *ptr)
>  	return !ptr || IS_ERR(ptr);
>  }
>  
> +#define div_u64(x, y) ((x) / (y))
> +
>  /**
>   * swap - swap values of @a and @b
>   * @a: first value
> @@ -297,6 +299,10 @@ static inline int IS_ERR_OR_NULL(const void *ptr)
>  #define kfree(x) free(x)
>  #define vmalloc(x) malloc(x)
>  #define vfree(x) free(x)
> +#define kvzalloc(x, y) kzalloc(x,y)
> +#define kvfree(x) free(x)
> +#define memalloc_nofs_save() (0)
> +#define memalloc_nofs_restore(x)
>  
>  #ifndef BTRFS_DISABLE_BACKTRACE
>  static inline void assert_trace(const char *assertion, const char *filename,
> -- 
> 2.7.4
> 

  reply	other threads:[~2018-10-04 18:26 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-10-01 14:46 [PATCH 00/10] Freespace tree repair support v2 Nikolay Borisov
2018-10-01 14:46 ` [PATCH 01/10] btrfs-progs: Add support for freespace tree in btrfs_read_fs_root Nikolay Borisov
2018-10-02 19:20   ` Omar Sandoval
2018-10-04  1:05   ` Su Yue
2018-10-01 14:46 ` [PATCH 02/10] btrfs-progs: Add extent buffer bitmap manipulation infrastructure Nikolay Borisov
2018-10-02 19:24   ` Omar Sandoval
2018-10-04  1:31   ` Su Yue
2018-10-01 14:46 ` [PATCH 03/10] btrfs-progs: Replace homegrown bitops related functions with kernel counterparts Nikolay Borisov
2018-10-02 23:32   ` Omar Sandoval
2018-10-01 14:46 ` [PATCH 04/10] btrfs-progs: Implement find_*_bit_le operations Nikolay Borisov
2018-10-04 18:08   ` Omar Sandoval
2018-10-04 18:09     ` Nikolay Borisov
2018-10-01 14:46 ` [PATCH 05/10] btrfs-progs: Pull free space tree related code from kernel Nikolay Borisov
2018-10-04 18:26   ` Omar Sandoval [this message]
2018-10-04 18:34     ` Nikolay Borisov
2018-10-04 19:01       ` Omar Sandoval
2018-10-23 14:05     ` David Sterba
2018-10-01 14:46 ` [PATCH 06/10] btrfs-progs: Hook FST code in extent (de)alloc Nikolay Borisov
2018-10-01 14:46 ` [PATCH 07/10] btrfs-progs: Add freespace tree as compat_ro supported feature Nikolay Borisov
2018-10-04 18:30   ` Omar Sandoval
2018-10-04 18:36     ` Nikolay Borisov
2018-10-01 14:46 ` [PATCH 08/10] btrfs-progs: check: Add support for freespace tree fixing Nikolay Borisov
2018-10-04 19:16   ` Omar Sandoval
2018-10-01 14:46 ` [PATCH 09/10] btrfs-progs: tests: Test for FST corruption detection/repair Nikolay Borisov
2018-10-01 14:46 ` [PATCH 10/10] btrfs-progs: check: Fix wrong error message in case of corrupted bitmap Nikolay Borisov
2018-10-04 19:18   ` Omar Sandoval
2018-10-23 15:00 ` [PATCH 00/10] Freespace tree repair support v2 David Sterba

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