Btrfs: progress on file_write (b18c6685) · Commits · e / devices / android_kernel_oneplus_sm7250

fs/btrfs/ctree.c

+57 −0

Original line number	Diff line number	Diff line
		@@ -1249,6 +1249,63 @@ static int split_leaf(struct btrfs_trans_handle *trans, struct btrfs_root
		return ret;
		}

		int btrfs_truncate_item(struct btrfs_trans_handle *trans,
		struct btrfs_root *root,
		struct btrfs_path *path,
		u32 new_size)
		{
		int ret = 0;
		int slot;
		int slot_orig;
		struct btrfs_leaf *leaf;
		struct buffer_head *leaf_buf;
		u32 nritems;
		unsigned int data_end;
		unsigned int old_data_start;
		unsigned int old_size;
		unsigned int size_diff;
		int i;

		slot_orig = path->slots[0];
		leaf_buf = path->nodes[0];
		leaf = btrfs_buffer_leaf(leaf_buf);

		nritems = btrfs_header_nritems(&leaf->header);
		data_end = leaf_data_end(root, leaf);

		slot = path->slots[0];
		old_data_start = btrfs_item_offset(leaf->items + slot);
		old_size = btrfs_item_size(leaf->items + slot);
		BUG_ON(old_size <= new_size);
		size_diff = old_size - new_size;

		BUG_ON(slot < 0);
		BUG_ON(slot >= nritems);

		/*
		* item0..itemN ... dataN.offset..dataN.size .. data0.size
		*/
		/* first correct the data pointers */
		for (i = slot; i < nritems; i++) {
		u32 ioff = btrfs_item_offset(leaf->items + i);
		btrfs_set_item_offset(leaf->items + i,
		ioff + size_diff);
		}
		/* shift the data */
		printk("truncate item, new_size %u old_size %u, diff %u, bufp %p, dst, %p, num %u, old_data_start %u, data_end %u\n", new_size, old_size, size_diff, leaf, btrfs_leaf_data(leaf) + data_end + size_diff, old_data_start-data_end, old_data_start, data_end);
		btrfs_memmove(root, leaf, btrfs_leaf_data(leaf) +
		data_end + size_diff, btrfs_leaf_data(leaf) +
		data_end, old_data_start + new_size - data_end);
		btrfs_set_item_size(leaf->items + slot, new_size);
		btrfs_mark_buffer_dirty(leaf_buf);

		ret = 0;
		if (btrfs_leaf_free_space(root, leaf) < 0)
		BUG();
		check_leaf(root, path, 0);
		return ret;
		}

		int btrfs_extend_item(struct btrfs_trans_handle *trans, struct btrfs_root
		root, struct btrfs_path path, u32 data_size)
		{

fs/btrfs/ctree.h

+16 −5

Original line number	Diff line number	Diff line
		@@ -999,7 +999,7 @@ static inline void btrfs_mark_buffer_dirty(struct buffer_head *bh)
		((type *)(btrfs_leaf_data(leaf) + \
		btrfs_item_offset((leaf)->items + (slot))))

		/* extent-item.c */
		/* extent-tree.c */
		int btrfs_inc_root_ref(struct btrfs_trans_handle *trans,
		struct btrfs_root *root);
		struct buffer_head btrfs_alloc_free_block(struct btrfs_trans_handle trans,
		@@ -1013,9 +1013,16 @@ int btrfs_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
		*root, u64 blocknr, u64 num_blocks, int pin);
		int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans, struct
		btrfs_root *root);
		int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
		struct btrfs_root *root,
		u64 blocknr, u64 num_blocks);
		/* ctree.c */
		int btrfs_extend_item(struct btrfs_trans_handle *trans, struct btrfs_root
		root, struct btrfs_path path, u32 data_size);
		int btrfs_truncate_item(struct btrfs_trans_handle *trans,
		struct btrfs_root *root,
		struct btrfs_path *path,
		u32 new_size);
		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);
		@@ -1073,11 +1080,10 @@ int btrfs_lookup_inode(struct btrfs_trans_handle *trans, struct btrfs_root
		struct btrfs_key *location, int mod);

		/* file-item.c */
		int btrfs_alloc_file_extent(struct btrfs_trans_handle *trans,
		int btrfs_insert_file_extent(struct btrfs_trans_handle *trans,
		struct btrfs_root *root,
		u64 objectid, u64 offset,
		u64 num_blocks, u64 hint_block,
		u64 *result);
		u64 objectid, u64 pos, u64 offset,
		u64 num_blocks);
		int btrfs_lookup_file_extent(struct btrfs_trans_handle *trans,
		struct btrfs_root *root,
		struct btrfs_path *path, u64 objectid,
		@@ -1090,6 +1096,11 @@ int btrfs_csum_file_block(struct btrfs_trans_handle *trans,
		int btrfs_csum_verify_file_block(struct btrfs_root *root,
		u64 objectid, u64 offset,
		char *data, size_t len);
		struct btrfs_csum_item btrfs_lookup_csum(struct btrfs_trans_handle trans,
		struct btrfs_root *root,
		struct btrfs_path *path,
		u64 objectid, u64 offset,
		int cow);
		/* super.c */
		extern struct subsystem btrfs_subsys;

fs/btrfs/extent-tree.c

+11 −9

Original line number	Diff line number	Diff line
		@@ -12,8 +12,9 @@ static int finish_current_insert(struct btrfs_trans_handle *trans, struct
		static int del_pending_extents(struct btrfs_trans_handle *trans, struct
		btrfs_root *extent_root);

		static int inc_block_ref(struct btrfs_trans_handle *trans, struct btrfs_root
		*root, u64 blocknr, u64 num_blocks)
		int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
		struct btrfs_root *root,
		u64 blocknr, u64 num_blocks)
		{
		struct btrfs_path *path;
		int ret;
		@@ -50,8 +51,9 @@ static int inc_block_ref(struct btrfs_trans_handle *trans, struct btrfs_root
		return 0;
		}

		static int lookup_block_ref(struct btrfs_trans_handle *trans, struct btrfs_root
		root, u64 blocknr, u64 num_blocks, u32 refs)
		static int lookup_extent_ref(struct btrfs_trans_handle *trans,
		struct btrfs_root *root, u64 blocknr,
		u64 num_blocks, u32 *refs)
		{
		struct btrfs_path *path;
		int ret;
		@@ -80,7 +82,7 @@ static int lookup_block_ref(struct btrfs_trans_handle *trans, struct btrfs_root
		int btrfs_inc_root_ref(struct btrfs_trans_handle *trans,
		struct btrfs_root *root)
		{
		return inc_block_ref(trans, root, bh_blocknr(root->node), 1);
		return btrfs_inc_extent_ref(trans, root, bh_blocknr(root->node), 1);
		}

		int btrfs_inc_ref(struct btrfs_trans_handle trans, struct btrfs_root root,
		@@ -107,13 +109,13 @@ int btrfs_inc_ref(struct btrfs_trans_handle trans, struct btrfs_root root,
		continue;
		fi = btrfs_item_ptr(buf_leaf, i,
		struct btrfs_file_extent_item);
		ret = inc_block_ref(trans, root,
		ret = btrfs_inc_extent_ref(trans, root,
		btrfs_file_extent_disk_blocknr(fi),
		btrfs_file_extent_disk_num_blocks(fi));
		BUG_ON(ret);
		} else {
		blocknr = btrfs_node_blockptr(buf_node, i);
		ret = inc_block_ref(trans, root, blocknr, 1);
		ret = btrfs_inc_extent_ref(trans, root, blocknr, 1);
		BUG_ON(ret);
		}
		}
		@@ -563,7 +565,7 @@ static int walk_down_tree(struct btrfs_trans_handle *trans, struct btrfs_root

		WARN_ON(*level < 0);
		WARN_ON(*level >= BTRFS_MAX_LEVEL);
		ret = lookup_block_ref(trans, root, bh_blocknr(path->nodes[*level]),
		ret = lookup_extent_ref(trans, root, bh_blocknr(path->nodes[*level]),
		1, &refs);
		BUG_ON(ret);
		if (refs > 1)
		@@ -587,7 +589,7 @@ static int walk_down_tree(struct btrfs_trans_handle *trans, struct btrfs_root
		}
		blocknr = btrfs_node_blockptr(btrfs_buffer_node(cur),
		path->slots[*level]);
		ret = lookup_block_ref(trans, root, blocknr, 1, &refs);
		ret = lookup_extent_ref(trans, root, blocknr, 1, &refs);
		BUG_ON(ret);
		if (refs != 1) {
		path->slots[*level]++;

fs/btrfs/file-item.c

+41 −20

Original line number	Diff line number	Diff line
		@@ -6,13 +6,11 @@
		#define MAX_CSUM_ITEMS(r) ((((BTRFS_LEAF_DATA_SIZE(r) - \
		sizeof(struct btrfs_item)) / \
		sizeof(struct btrfs_csum_item)) - 1))
		int btrfs_alloc_file_extent(struct btrfs_trans_handle *trans,
		int btrfs_insert_file_extent(struct btrfs_trans_handle *trans,
		struct btrfs_root *root,
		u64 objectid, u64 offset,
		u64 num_blocks, u64 hint_block,
		u64 *result)
		u64 objectid, u64 pos,
		u64 offset, u64 num_blocks)
		{
		struct btrfs_key ins;
		int ret = 0;
		struct btrfs_file_extent_item *item;
		struct btrfs_key file_key;
		@@ -21,11 +19,13 @@ int btrfs_alloc_file_extent(struct btrfs_trans_handle *trans,
		path = btrfs_alloc_path();
		BUG_ON(!path);
		btrfs_init_path(path);
		/*
		ret = btrfs_alloc_extent(trans, root, num_blocks, hint_block,
		(u64)-1, &ins);
		*/
		BUG_ON(ret);
		file_key.objectid = objectid;
		file_key.offset = offset;
		file_key.offset = pos;
		file_key.flags = 0;
		btrfs_set_key_type(&file_key, BTRFS_EXTENT_DATA_KEY);

		@@ -34,21 +34,22 @@ int btrfs_alloc_file_extent(struct btrfs_trans_handle *trans,
		BUG_ON(ret);
		item = btrfs_item_ptr(btrfs_buffer_leaf(path->nodes[0]), path->slots[0],
		struct btrfs_file_extent_item);
		btrfs_set_file_extent_disk_blocknr(item, ins.objectid);
		btrfs_set_file_extent_disk_num_blocks(item, ins.offset);
		btrfs_set_file_extent_disk_blocknr(item, offset);
		btrfs_set_file_extent_disk_num_blocks(item, num_blocks);
		btrfs_set_file_extent_offset(item, 0);
		btrfs_set_file_extent_num_blocks(item, ins.offset);
		btrfs_set_file_extent_num_blocks(item, num_blocks);
		btrfs_set_file_extent_generation(item, trans->transid);
		btrfs_mark_buffer_dirty(path->nodes[0]);
		*result = ins.objectid;
		btrfs_release_path(root, path);
		btrfs_free_path(path);
		return 0;
		}

		static struct btrfs_csum_item __lookup_csum_item(struct btrfs_root root,
		struct btrfs_csum_item btrfs_lookup_csum(struct btrfs_trans_handle trans,
		struct btrfs_root *root,
		struct btrfs_path *path,
		u64 objectid, u64 offset)
		u64 objectid, u64 offset,
		int cow)
		{
		int ret;
		struct btrfs_key file_key;
		@@ -61,19 +62,23 @@ static struct btrfs_csum_item __lookup_csum_item(struct btrfs_root root,
		file_key.offset = offset;
		file_key.flags = 0;
		btrfs_set_key_type(&file_key, BTRFS_CSUM_ITEM_KEY);
		ret = btrfs_search_slot(NULL, root, &file_key, path, 0, 0);
		printk("__lookup for %Lu\n", offset);
		ret = btrfs_search_slot(trans, root, &file_key, path, 0, cow);
		if (ret < 0)
		goto fail;
		leaf = btrfs_buffer_leaf(path->nodes[0]);
		if (ret > 0) {
		ret = 1;
		if (path->slots[0] == 0)
		if (path->slots[0] == 0) {
		printk("fail1\n");
		goto fail;
		}
		path->slots[0]--;
		btrfs_disk_key_to_cpu(&found_key,
		&leaf->items[path->slots[0]].key);
		if (btrfs_key_type(&found_key) != BTRFS_CSUM_ITEM_KEY \|\|
		found_key.objectid != objectid) {
		printk("fail2 type %u %Lu %Lu\n", btrfs_key_type(&found_key), found_key.objectid, objectid);
		goto fail;
		}
		csum_offset = (offset - found_key.offset) >>
		@@ -81,6 +86,7 @@ static struct btrfs_csum_item __lookup_csum_item(struct btrfs_root root,
		if (csum_offset >=
		btrfs_item_size(leaf->items + path->slots[0]) /
		sizeof(struct btrfs_csum_item)) {
		printk("fail3, csum offset %lu size %u\n", csum_offset, btrfs_item_size(leaf->items + path->slots[0]) / sizeof(struct btrfs_csum_item));
		goto fail;
		}
		}
		@@ -89,7 +95,7 @@ static struct btrfs_csum_item __lookup_csum_item(struct btrfs_root root,
		return item;
		fail:
		if (ret > 0)
		ret = -EIO;
		ret = -ENOENT;
		return ERR_PTR(ret);
		}

		@@ -105,7 +111,7 @@ int btrfs_lookup_file_extent(struct btrfs_trans_handle *trans,
		int cow = mod != 0;
		struct btrfs_csum_item *csum_item;

		csum_item = __lookup_csum_item(root, path, objectid, offset);
		csum_item = btrfs_lookup_csum(trans, root, path, objectid, offset, 0);
		if (IS_ERR(csum_item))
		return PTR_ERR(csum_item);
		file_key.objectid = objectid;
		@@ -113,7 +119,9 @@ int btrfs_lookup_file_extent(struct btrfs_trans_handle *trans,
		file_key.flags = 0;
		btrfs_set_key_type(&file_key, BTRFS_EXTENT_DATA_KEY);
		btrfs_release_path(root, path);
		printk("lookup file extent searches for %Lu\n", file_key.offset);
		ret = btrfs_search_slot(trans, root, &file_key, path, ins_len, cow);
		printk("ret is %d\n", ret);
		return ret;
		}

		@@ -134,17 +142,23 @@ int btrfs_csum_file_block(struct btrfs_trans_handle *trans,
		path = btrfs_alloc_path();
		BUG_ON(!path);
		btrfs_init_path(path);

		item = btrfs_lookup_csum(trans, root, path, objectid, offset, 0);
		if (!IS_ERR(item))
		goto found;
		btrfs_release_path(root, path);
		file_key.objectid = objectid;
		file_key.offset = offset;
		file_key.flags = 0;
		btrfs_set_key_type(&file_key, BTRFS_CSUM_ITEM_KEY);
		printk("searching for csum %Lu %Lu\n", objectid, offset);
		ret = btrfs_search_slot(trans, root, &file_key, path,
		sizeof(struct btrfs_csum_item), 1);
		printk("ret %d\n", ret);
		if (ret < 0)
		goto fail;
		if (ret == 0) {
		csum_offset = 0;
		goto csum;
		BUG();
		}
		if (path->slots[0] == 0) {
		btrfs_release_path(root, path);
		@@ -153,12 +167,15 @@ int btrfs_csum_file_block(struct btrfs_trans_handle *trans,
		path->slots[0]--;
		leaf = btrfs_buffer_leaf(path->nodes[0]);
		btrfs_disk_key_to_cpu(&found_key, &leaf->items[path->slots[0]].key);
		printk("found key %Lu %Lu %u\n", found_key.objectid, found_key.offset, found_key.flags);
		csum_offset = (offset - found_key.offset) >>
		root->fs_info->sb->s_blocksize_bits;
		printk("csum_offset %Lu\n", csum_offset);
		if (btrfs_key_type(&found_key) != BTRFS_CSUM_ITEM_KEY \|\|
		found_key.objectid != objectid \|\|
		csum_offset >= MAX_CSUM_ITEMS(root)) {
		btrfs_release_path(root, path);
		printk("insert1\n");
		goto insert;
		}
		if (csum_offset >= btrfs_item_size(leaf->items + path->slots[0]) /
		@@ -166,11 +183,13 @@ int btrfs_csum_file_block(struct btrfs_trans_handle *trans,
		ret = btrfs_extend_item(trans, root, path,
		sizeof(struct btrfs_csum_item));
		BUG_ON(ret);
		printk("item extended\n");
		goto csum;
		}

		insert:
		csum_offset = 0;
		printk("inserting item %Lu %Lu %u\n", file_key.objectid, file_key.offset, file_key.flags);
		ret = btrfs_insert_empty_item(trans, root, path, &file_key,
		sizeof(struct btrfs_csum_item));
		if (ret != 0 && ret != -EEXIST)
		@@ -180,12 +199,14 @@ int btrfs_csum_file_block(struct btrfs_trans_handle *trans,
		struct btrfs_csum_item);
		ret = 0;
		item += csum_offset;
		found:
		ret = btrfs_csum_data(root, data, len, item->csum);
		btrfs_set_csum_extent_offset(item, extent_offset);
		btrfs_mark_buffer_dirty(path->nodes[0]);
		fail:
		btrfs_release_path(root, path);
		btrfs_free_path(path);
		printk("return ret %d\n", ret);
		return ret;
		}

		@@ -208,7 +229,7 @@ int btrfs_csum_verify_file_block(struct btrfs_root *root,
		btrfs_set_key_type(&file_key, BTRFS_CSUM_ITEM_KEY);
		mutex_lock(&root->fs_info->fs_mutex);

		item = __lookup_csum_item(root, path, objectid, offset);
		item = btrfs_lookup_csum(NULL, root, path, objectid, offset, 0);
		if (IS_ERR(item)) {
		ret = PTR_ERR(item);
		goto fail;

fs/btrfs/super.c

+269 −15

Original line number	Diff line number	Diff line
		@@ -1089,7 +1089,6 @@ static int btrfs_get_block_lock(struct inode *inode, sector_t iblock,

		extent_start = btrfs_disk_key_offset(&leaf->items[path->slots[0]].key);
		extent_start = extent_start >> inode->i_blkbits;
		extent_start += btrfs_file_extent_offset(item);
		extent_end = extent_start + btrfs_file_extent_num_blocks(item);
		if (iblock >= extent_start && iblock < extent_end) {
		err = 0;
		@@ -1103,6 +1102,7 @@ static int btrfs_get_block_lock(struct inode *inode, sector_t iblock,
		err = 0;
		goto out;
		}
		#if 0
		ret = btrfs_alloc_file_extent(trans, root, objectid,
		iblock << inode->i_blkbits,
		1, extent_end, &blocknr);
		@@ -1115,9 +1115,11 @@ static int btrfs_get_block_lock(struct inode *inode, sector_t iblock,
		map_bh(result, inode->i_sb, blocknr);

		btrfs_map_bh_to_logical(root, result, blocknr);
		#endif
		out:
		btrfs_release_path(root, path);
		btrfs_free_path(path);
		printk("mapping iblock %lu to %lu\n", iblock, result->b_blocknr);
		if (trans)
		btrfs_end_transaction(trans, root);
		return err;
		@@ -1273,8 +1275,244 @@ static int dirty_and_release_pages(struct btrfs_trans_handle *trans,
		return err;
		}

		static int prepare_pages(struct btrfs_trans_handle *trans,
		static int drop_csums(struct btrfs_trans_handle *trans,
		struct btrfs_root *root,
		struct inode *inode,
		u64 start, u64 end)
		{
		struct btrfs_path *path;
		struct btrfs_leaf *leaf;
		struct btrfs_key key;
		int slot;
		struct btrfs_csum_item *item;
		char *old_block = NULL;
		u64 cur = start;
		u64 found_end;
		u64 num_csums;
		u64 item_size;
		int ret;

		path = btrfs_alloc_path();
		if (!path)
		return -ENOMEM;
		while(cur < end) {
		item = btrfs_lookup_csum(trans, root, path,
		inode->i_ino, cur, 1);
		if (IS_ERR(item)) {
		cur += root->blocksize;
		continue;
		}
		leaf = btrfs_buffer_leaf(path->nodes[0]);
		slot = path->slots[0];
		btrfs_disk_key_to_cpu(&key, &leaf->items[slot].key);
		item_size = btrfs_item_size(leaf->items + slot);
		num_csums = item_size / sizeof(struct btrfs_csum_item);
		found_end = key.offset + (num_csums << inode->i_blkbits);
		cur = found_end;

		if (found_end > end) {
		char *src;
		old_block = kmalloc(root->blocksize, GFP_NOFS);
		src = btrfs_item_ptr(leaf, slot, char);
		memcpy(old_block, src, item_size);
		}
		if (key.offset < start) {
		u64 new_size = (start - key.offset) >>
		inode->i_blkbits;
		new_size *= sizeof(struct btrfs_csum_item);
		ret = btrfs_truncate_item(trans, root, path, new_size);
		BUG_ON(ret);
		} else {
		btrfs_del_item(trans, root, path);
		}
		btrfs_release_path(root, path);
		if (found_end > end) {
		char *dst;
		int i;
		int new_size;

		num_csums = (found_end - end) >> inode->i_blkbits;
		new_size = num_csums * sizeof(struct btrfs_csum_item);
		key.offset = end;
		ret = btrfs_insert_empty_item(trans, root, path,
		&key, new_size);
		BUG_ON(ret);
		dst = btrfs_item_ptr(btrfs_buffer_leaf(path->nodes[0]),
		path->slots[0], char);
		memcpy(dst, old_block + item_size - new_size,
		new_size);
		item = (struct btrfs_csum_item *)dst;
		for (i = 0; i < num_csums; i++) {
		btrfs_set_csum_extent_offset(item, end);
		item++;
		}
		mark_buffer_dirty(path->nodes[0]);
		kfree(old_block);
		break;
		}
		}
		btrfs_free_path(path);
		return 0;
		}

		static int drop_extents(struct btrfs_trans_handle *trans,
		struct btrfs_root *root,
		struct inode *inode,
		u64 start, u64 end)
		{
		int ret;
		struct btrfs_key key;
		struct btrfs_leaf *leaf;
		int slot;
		struct btrfs_file_extent_item *extent;
		u64 extent_end;
		int keep;
		struct btrfs_file_extent_item old;
		struct btrfs_path *path;
		u64 search_start = start;
		int bookend;

		path = btrfs_alloc_path();
		if (!path)
		return -ENOMEM;
		search_again:
		printk("drop extent inode %lu start %Lu end %Lu\n", inode->i_ino, start, end);
		ret = btrfs_lookup_file_extent(trans, root, path, inode->i_ino,
		search_start, -1);
		if (ret != 0) {
		printk("lookup failed\n");
		goto out;
		}
		while(1) {
		keep = 0;
		bookend = 0;
		leaf = btrfs_buffer_leaf(path->nodes[0]);
		slot = path->slots[0];
		btrfs_disk_key_to_cpu(&key, &leaf->items[slot].key);

		printk("found key %Lu %Lu %u\n", key.objectid, key.offset, key.flags);

		extent = btrfs_item_ptr(leaf, slot,
		struct btrfs_file_extent_item);
		extent_end = key.offset +
		(btrfs_file_extent_num_blocks(extent) <<
		inode->i_blkbits);
		printk("extent end is %Lu\n", extent_end);
		if (key.offset >= end \|\| key.objectid != inode->i_ino) {
		ret = 0;
		goto out;
		}
		if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
		goto next_leaf;

		if (end < extent_end && end >= key.offset) {
		memcpy(&old, extent, sizeof(old));
		ret = btrfs_inc_extent_ref(trans, root,
		btrfs_file_extent_disk_blocknr(&old),
		btrfs_file_extent_disk_num_blocks(&old));
		BUG_ON(ret);
		bookend = 1;
		}

		if (start > key.offset) {
		u64 new_num;
		/* truncate existing extent */
		keep = 1;
		WARN_ON(start & (root->blocksize - 1));
		new_num = (start - key.offset) >> inode->i_blkbits;
		printk("truncating existing extent, was %Lu ", btrfs_file_extent_num_blocks(extent));
		btrfs_set_file_extent_num_blocks(extent, new_num);
		printk("now %Lu\n", btrfs_file_extent_num_blocks(extent));

		mark_buffer_dirty(path->nodes[0]);
		}
		if (!keep) {
		u64 disk_blocknr;
		u64 disk_num_blocks;
		printk("del old\n");
		disk_blocknr = btrfs_file_extent_disk_blocknr(extent);
		disk_num_blocks =
		btrfs_file_extent_disk_num_blocks(extent);
		search_start = key.offset +
		(btrfs_file_extent_num_blocks(extent) <<
		inode->i_blkbits);
		ret = btrfs_del_item(trans, root, path);
		BUG_ON(ret);
		btrfs_release_path(root, path);

		ret = btrfs_free_extent(trans, root, disk_blocknr,
		disk_num_blocks, 0);

		BUG_ON(ret);
		if (!bookend && search_start >= end) {
		ret = 0;
		goto out;
		}
		if (!bookend)
		goto search_again;
		}
		if (bookend) {
		/* create bookend */
		struct btrfs_key ins;
		printk("bookend! extent end %Lu\n", extent_end);
		ins.objectid = inode->i_ino;
		ins.offset = end;
		ins.flags = 0;
		btrfs_set_key_type(&ins, BTRFS_EXTENT_DATA_KEY);

		btrfs_release_path(root, path);
		ret = drop_csums(trans, root, inode, start, end);
		BUG_ON(ret);
		ret = btrfs_insert_empty_item(trans, root, path, &ins,
		sizeof(*extent));
		BUG_ON(ret);
		extent = btrfs_item_ptr(
		btrfs_buffer_leaf(path->nodes[0]),
		path->slots[0],
		struct btrfs_file_extent_item);
		btrfs_set_file_extent_disk_blocknr(extent,
		btrfs_file_extent_disk_blocknr(&old));
		btrfs_set_file_extent_disk_num_blocks(extent,
		btrfs_file_extent_disk_num_blocks(&old));

		btrfs_set_file_extent_offset(extent,
		btrfs_file_extent_offset(&old) +
		((end - key.offset) >> inode->i_blkbits));
		WARN_ON(btrfs_file_extent_num_blocks(&old) <
		(end - key.offset) >> inode->i_blkbits);
		btrfs_set_file_extent_num_blocks(extent,
		btrfs_file_extent_num_blocks(&old) -
		((end - key.offset) >> inode->i_blkbits));

		btrfs_set_file_extent_generation(extent,
		btrfs_file_extent_generation(&old));
		printk("new bookend at offset %Lu, file_extent_offset %Lu, file_extent_num_blocks %Lu\n", end, btrfs_file_extent_offset(extent), btrfs_file_extent_num_blocks(extent));
		btrfs_mark_buffer_dirty(path->nodes[0]);
		ret = 0;
		goto out_nocsum;
		}
		next_leaf:
		if (slot >= btrfs_header_nritems(&leaf->header) - 1) {
		ret = btrfs_next_leaf(root, path);
		if (ret) {
		ret = 0;
		goto out;
		}
		} else {
		path->slots[0]++;
		}
		}

		out:
		ret = drop_csums(trans, root, inode, start, end);
		BUG_ON(ret);

		out_nocsum:
		btrfs_free_path(path);
		return ret;
		}

		static int prepare_pages(struct btrfs_root *root,
		struct file *file,
		struct page **pages,
		size_t num_pages,
		@@ -1289,7 +1527,6 @@ static int prepare_pages(struct btrfs_trans_handle *trans,
		struct inode *inode = file->f_path.dentry->d_inode;
		int offset;
		int err = 0;
		int ret;
		int this_write;
		struct buffer_head *bh;
		struct buffer_head *head;
		@@ -1305,18 +1542,21 @@ static int prepare_pages(struct btrfs_trans_handle *trans,
		}
		offset = pos & (PAGE_CACHE_SIZE -1);
		this_write = min(PAGE_CACHE_SIZE - offset, write_bytes);
		if (!PageUptodate(pages[i]) &&
		(pages[i]->index == first_index \|\|
		pages[i]->index == last_index) && pos < isize) {
		#if 0
		if ((pages[i]->index == first_index \|\|
		pages[i]->index == last_index) && pos < isize &&
		!PageUptodate(pages[i])) {
		ret = mpage_readpage(pages[i], btrfs_get_block);
		BUG_ON(ret);
		lock_page(pages[i]);
		}
		#endif
		create_empty_buffers(pages[i], root->fs_info->sb->s_blocksize,
		(1 << BH_Uptodate));
		head = page_buffers(pages[i]);
		bh = head;
		do {
		printk("mapping page %lu to block %Lu\n", pages[i]->index, alloc_extent_start);
		err = btrfs_map_bh_to_logical(root, bh,
		alloc_extent_start);
		BUG_ON(err);
		@@ -1351,7 +1591,7 @@ static ssize_t btrfs_file_write(struct file file, const char __user buf,
		int ret = 0;
		struct inode *inode = file->f_path.dentry->d_inode;
		struct btrfs_root *root = BTRFS_I(inode)->root;
		struct page *pages[1];
		struct page *pages[8];
		unsigned long first_index;
		unsigned long last_index;
		u64 start_pos;
		@@ -1359,6 +1599,7 @@ static ssize_t btrfs_file_write(struct file file, const char __user buf,
		u64 alloc_extent_start;
		u64 orig_extent_start;
		struct btrfs_trans_handle *trans;
		struct btrfs_key ins;

		if (file->f_flags & O_DIRECT)
		return -EINVAL;
		@@ -1390,16 +1631,24 @@ static ssize_t btrfs_file_write(struct file file, const char __user buf,
		trans = btrfs_start_transaction(root, 1);
		if (!trans) {
		err = -ENOMEM;
		mutex_unlock(&root->fs_info->fs_mutex);
		goto out_unlock;
		}
		ret = btrfs_alloc_file_extent(trans, root, inode->i_ino,
		start_pos, num_blocks, 1,
		&alloc_extent_start);
		BUG_ON(ret);

		if (start_pos < inode->i_size) {
		ret = drop_extents(trans, root, inode,
		start_pos,
		(pos + count + root->blocksize -1) &
		~(root->blocksize - 1));
		}
		orig_extent_start = start_pos;
		ret = btrfs_end_transaction(trans, root);
		ret = btrfs_alloc_extent(trans, root, num_blocks, 1,
		(u64)-1, &ins);
		BUG_ON(ret);
		ret = btrfs_insert_file_extent(trans, root, inode->i_ino,
		start_pos, ins.objectid, ins.offset);
		BUG_ON(ret);
		alloc_extent_start = ins.objectid;
		ret = btrfs_end_transaction(trans, root);
		mutex_unlock(&root->fs_info->fs_mutex);

		while(count > 0) {
		@@ -1407,16 +1656,21 @@ static ssize_t btrfs_file_write(struct file file, const char __user buf,
		size_t write_bytes = min(count, PAGE_CACHE_SIZE - offset);
		size_t num_pages = (write_bytes + PAGE_CACHE_SIZE - 1) >>
		PAGE_CACHE_SHIFT;
		ret = prepare_pages(NULL, root, file, pages, num_pages,
		printk("num_pages is %lu\n", num_pages);

		memset(pages, 0, sizeof(pages));
		ret = prepare_pages(root, file, pages, num_pages,
		pos, first_index, last_index,
		write_bytes, alloc_extent_start);
		BUG_ON(ret);

		/* FIXME blocks != pagesize */
		alloc_extent_start += num_pages;
		ret = btrfs_copy_from_user(pos, num_pages,
		write_bytes, pages, buf);
		BUG_ON(ret);

		printk("2num_pages is %lu\n", num_pages);
		ret = dirty_and_release_pages(NULL, root, file, pages,
		num_pages, orig_extent_start,
		pos, write_bytes);