fs/btrfs/file-item.c - linux - Git at Google

 /*
  * Copyright (C) 2007 Oracle.  All rights reserved.
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public
  * License v2 as published by the Free Software Foundation.
  *
  * This program is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * General Public License for more details.
  *
  * You should have received a copy of the GNU General Public
  * License along with this program; if not, write to the
  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  * Boston, MA 021110-1307, USA.
  */

 #include "ctree.h"
 #include "disk-io.h"
 #include "transaction.h"
 #include "print-tree.h"

 #define MAX_CSUM_ITEMS(r) ((((BTRFS_LEAF_DATA_SIZE(r) - \
 			       sizeof(struct btrfs_item) * 2) / \
 			       BTRFS_CRC32_SIZE) - 1))
 int btrfs_insert_file_extent(struct btrfs_trans_handle *trans,
 			       struct btrfs_root *root,
 			       u64 objectid, u64 pos,
 			       u64 offset, u64 disk_num_bytes,
 			       u64 num_bytes)
 {
 	int ret = 0;
 	struct btrfs_file_extent_item *item;
 	struct btrfs_key file_key;
 	struct btrfs_path *path;
 	struct extent_buffer *leaf;

 	path = btrfs_alloc_path();
 	BUG_ON(!path);
 	file_key.objectid = objectid;
 	file_key.offset = pos;
 	btrfs_set_key_type(&file_key, BTRFS_EXTENT_DATA_KEY);

 	ret = btrfs_insert_empty_item(trans, root, path, &file_key,
 				      sizeof(*item));
 	if (ret < 0)
 		goto out;
 	BUG_ON(ret);
 	leaf = path->nodes[0];
 	item = btrfs_item_ptr(leaf, path->slots[0],
 			      struct btrfs_file_extent_item);
 	btrfs_set_file_extent_disk_bytenr(leaf, item, offset);
 	btrfs_set_file_extent_disk_num_bytes(leaf, item, disk_num_bytes);
 	btrfs_set_file_extent_offset(leaf, item, 0);
 	btrfs_set_file_extent_num_bytes(leaf, item, num_bytes);
 	btrfs_set_file_extent_generation(leaf, item, trans->transid);
 	btrfs_set_file_extent_type(leaf, item, BTRFS_FILE_EXTENT_REG);
 	btrfs_mark_buffer_dirty(leaf);
 out:
 	btrfs_free_path(path);
 	return ret;
 }

 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)
 {
 	int ret;
 	struct btrfs_key file_key;
 	struct btrfs_key found_key;
 	struct btrfs_csum_item *item;
 	struct extent_buffer *leaf;
 	u64 csum_offset = 0;
 	int csums_in_item;

 	file_key.objectid = objectid;
 	file_key.offset = offset;
 	btrfs_set_key_type(&file_key, BTRFS_CSUM_ITEM_KEY);
 	ret = btrfs_search_slot(trans, root, &file_key, path, 0, cow);
 	if (ret < 0)
 		goto fail;
 	leaf = path->nodes[0];
 	if (ret > 0) {
 		ret = 1;
 		if (path->slots[0] == 0)
 			goto fail;
 		path->slots[0]--;
 		btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
 		if (btrfs_key_type(&found_key) != BTRFS_CSUM_ITEM_KEY ||
 		    found_key.objectid != objectid) {
 			goto fail;
 		}
 		csum_offset = (offset - found_key.offset) >>
 				root->fs_info->sb->s_blocksize_bits;
 		csums_in_item = btrfs_item_size_nr(leaf, path->slots[0]);
 		csums_in_item /= BTRFS_CRC32_SIZE;

 		if (csum_offset >= csums_in_item) {
 			ret = -EFBIG;
 			goto fail;
 		}
 	}
 	item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_csum_item);
 	item = (struct btrfs_csum_item *)((unsigned char *)item +
 					  csum_offset * BTRFS_CRC32_SIZE);
 	return item;
 fail:
 	if (ret > 0)
 		ret = -ENOENT;
 	return ERR_PTR(ret);
 }


 int btrfs_lookup_file_extent(struct btrfs_trans_handle *trans,
 			     struct btrfs_root *root,
 			     struct btrfs_path *path, u64 objectid,
 			     u64 offset, int mod)
 {
 	int ret;
 	struct btrfs_key file_key;
 	int ins_len = mod < 0 ? -1 : 0;
 	int cow = mod != 0;

 	file_key.objectid = objectid;
 	file_key.offset = offset;
 	btrfs_set_key_type(&file_key, BTRFS_EXTENT_DATA_KEY);
 	ret = btrfs_search_slot(trans, root, &file_key, path, ins_len, cow);
 	return ret;
 }

 int btrfs_csum_file_block(struct btrfs_trans_handle *trans,
 			  struct btrfs_root *root,
 			  u64 objectid, u64 offset,
 			  char *data, size_t len)
 {
 	int ret;
 	struct btrfs_key file_key;
 	struct btrfs_key found_key;
 	struct btrfs_path *path;
 	struct btrfs_csum_item *item;
 	struct extent_buffer *leaf = NULL;
 	u64 csum_offset;
 	u32 csum_result = ~(u32)0;

 	path = btrfs_alloc_path();
 	BUG_ON(!path);

 	file_key.objectid = objectid;
 	file_key.offset = offset;
 	btrfs_set_key_type(&file_key, BTRFS_CSUM_ITEM_KEY);

 	item = btrfs_lookup_csum(trans, root, path, objectid, offset, 1);
 	if (!IS_ERR(item)) {
 		leaf = path->nodes[0];
 		goto found;
 	}
 	ret = PTR_ERR(item);
 	if (ret == -EFBIG) {
 		u32 item_size;
 		/* we found one, but it isn't big enough yet */
 		leaf = path->nodes[0];
 		item_size = btrfs_item_size_nr(leaf, path->slots[0]);
 		if ((item_size / BTRFS_CRC32_SIZE) >= MAX_CSUM_ITEMS(root)) {
 			/* already at max size, make a new one */
 			goto insert;
 		}
 	} else {
 		/* we didn't find a csum item, insert one */
 		goto insert;
 	}

 	/*
 	 * at this point, we know the tree has an item, but it isn't big
 	 * enough yet to put our csum in.  Grow it
 	 */
 	btrfs_release_path(root, path);
 	ret = btrfs_search_slot(trans, root, &file_key, path,
 				BTRFS_CRC32_SIZE, 1);
 	if (ret < 0)
 		goto fail;
 	if (ret == 0) {
 		BUG();
 	}
 	if (path->slots[0] == 0) {
 		goto insert;
 	}
 	path->slots[0]--;
 	leaf = path->nodes[0];
 	btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
 	csum_offset = (offset - found_key.offset) >>
 			root->fs_info->sb->s_blocksize_bits;
 	if (btrfs_key_type(&found_key) != BTRFS_CSUM_ITEM_KEY ||
 	    found_key.objectid != objectid ||
 	    csum_offset >= MAX_CSUM_ITEMS(root)) {
 		goto insert;
 	}
 	if (csum_offset >= btrfs_item_size_nr(leaf, path->slots[0]) /
 	    BTRFS_CRC32_SIZE) {
 		u32 diff = (csum_offset + 1) * BTRFS_CRC32_SIZE;
 		diff = diff - btrfs_item_size_nr(leaf, path->slots[0]);
 		if (diff != BTRFS_CRC32_SIZE)
 			goto insert;
 		ret = btrfs_extend_item(trans, root, path, diff);
 		BUG_ON(ret);
 		goto csum;
 	}

 insert:
 	btrfs_release_path(root, path);
 	csum_offset = 0;
 	ret = btrfs_insert_empty_item(trans, root, path, &file_key,
 				      BTRFS_CRC32_SIZE);
 	if (ret < 0)
 		goto fail;
 	if (ret != 0) {
 		WARN_ON(1);
 		goto fail;
 	}
 csum:
 	leaf = path->nodes[0];
 	item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_csum_item);
 	ret = 0;
 	item = (struct btrfs_csum_item *)((unsigned char *)item +
 					  csum_offset * BTRFS_CRC32_SIZE);
 found:
 	csum_result = btrfs_csum_data(root, data, csum_result, len);
 	btrfs_csum_final(csum_result, (char *)&csum_result);
 	write_extent_buffer(leaf, &csum_result, (unsigned long)item,
 			    BTRFS_CRC32_SIZE);
 	btrfs_mark_buffer_dirty(path->nodes[0]);
 fail:
 	btrfs_release_path(root, path);
 	btrfs_free_path(path);
 	return ret;
 }

 int btrfs_csum_truncate(struct btrfs_trans_handle *trans,
 			struct btrfs_root *root, struct btrfs_path *path,
 			u64 isize)
 {
 	struct btrfs_key key;
 	struct extent_buffer *leaf = path->nodes[0];
 	int slot = path->slots[0];
 	int ret;
 	u32 new_item_size;
 	u64 new_item_span;
 	u64 blocks;

 	btrfs_item_key_to_cpu(leaf, &key, slot);
 	if (isize <= key.offset)
 		return 0;
 	new_item_span = isize - key.offset;
 	blocks = (new_item_span + root->sectorsize - 1) >>
 		root->fs_info->sb->s_blocksize_bits;
 	new_item_size = blocks * BTRFS_CRC32_SIZE;
 	if (new_item_size >= btrfs_item_size_nr(leaf, slot))
 		return 0;
 	ret = btrfs_truncate_item(trans, root, path, new_item_size);
 	BUG_ON(ret);
 	return ret;
 }
	/*
	* Copyright (C) 2007 Oracle. All rights reserved.
	*
	* This program is free software; you can redistribute it and/or
	* modify it under the terms of the GNU General Public
	* License v2 as published by the Free Software Foundation.
	*
	* This program is distributed in the hope that it will be useful,
	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	* General Public License for more details.
	*
	* You should have received a copy of the GNU General Public
	* License along with this program; if not, write to the
	* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
	* Boston, MA 021110-1307, USA.
	*/

	#include "ctree.h"
	#include "disk-io.h"
	#include "transaction.h"
	#include "print-tree.h"

	#define MAX_CSUM_ITEMS(r) ((((BTRFS_LEAF_DATA_SIZE(r) - \
	sizeof(struct btrfs_item) * 2) / \
	BTRFS_CRC32_SIZE) - 1))
	int btrfs_insert_file_extent(struct btrfs_trans_handle *trans,
	struct btrfs_root *root,
	u64 objectid, u64 pos,
	u64 offset, u64 disk_num_bytes,
	u64 num_bytes)
	{
	int ret = 0;
	struct btrfs_file_extent_item *item;
	struct btrfs_key file_key;
	struct btrfs_path *path;
	struct extent_buffer *leaf;

	path = btrfs_alloc_path();
	BUG_ON(!path);
	file_key.objectid = objectid;
	file_key.offset = pos;
	btrfs_set_key_type(&file_key, BTRFS_EXTENT_DATA_KEY);

	ret = btrfs_insert_empty_item(trans, root, path, &file_key,
	sizeof(*item));
	if (ret < 0)
	goto out;
	BUG_ON(ret);
	leaf = path->nodes[0];
	item = btrfs_item_ptr(leaf, path->slots[0],
	struct btrfs_file_extent_item);
	btrfs_set_file_extent_disk_bytenr(leaf, item, offset);
	btrfs_set_file_extent_disk_num_bytes(leaf, item, disk_num_bytes);
	btrfs_set_file_extent_offset(leaf, item, 0);
	btrfs_set_file_extent_num_bytes(leaf, item, num_bytes);
	btrfs_set_file_extent_generation(leaf, item, trans->transid);
	btrfs_set_file_extent_type(leaf, item, BTRFS_FILE_EXTENT_REG);
	btrfs_mark_buffer_dirty(leaf);
	out:
	btrfs_free_path(path);
	return ret;
	}

	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)
	{
	int ret;
	struct btrfs_key file_key;
	struct btrfs_key found_key;
	struct btrfs_csum_item *item;
	struct extent_buffer *leaf;
	u64 csum_offset = 0;
	int csums_in_item;

	file_key.objectid = objectid;
	file_key.offset = offset;
	btrfs_set_key_type(&file_key, BTRFS_CSUM_ITEM_KEY);
	ret = btrfs_search_slot(trans, root, &file_key, path, 0, cow);
	if (ret < 0)
	goto fail;
	leaf = path->nodes[0];
	if (ret > 0) {
	ret = 1;
	if (path->slots[0] == 0)
	goto fail;
	path->slots[0]--;
	btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
	if (btrfs_key_type(&found_key) != BTRFS_CSUM_ITEM_KEY \|\|
	found_key.objectid != objectid) {
	goto fail;
	}
	csum_offset = (offset - found_key.offset) >>
	root->fs_info->sb->s_blocksize_bits;
	csums_in_item = btrfs_item_size_nr(leaf, path->slots[0]);
	csums_in_item /= BTRFS_CRC32_SIZE;

	if (csum_offset >= csums_in_item) {
	ret = -EFBIG;
	goto fail;
	}
	}
	item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_csum_item);
	item = (struct btrfs_csum_item )((unsigned char )item +
	csum_offset * BTRFS_CRC32_SIZE);
	return item;
	fail:
	if (ret > 0)
	ret = -ENOENT;
	return ERR_PTR(ret);
	}


	int btrfs_lookup_file_extent(struct btrfs_trans_handle *trans,
	struct btrfs_root *root,
	struct btrfs_path *path, u64 objectid,
	u64 offset, int mod)
	{
	int ret;
	struct btrfs_key file_key;
	int ins_len = mod < 0 ? -1 : 0;
	int cow = mod != 0;

	file_key.objectid = objectid;
	file_key.offset = offset;
	btrfs_set_key_type(&file_key, BTRFS_EXTENT_DATA_KEY);
	ret = btrfs_search_slot(trans, root, &file_key, path, ins_len, cow);
	return ret;
	}

	int btrfs_csum_file_block(struct btrfs_trans_handle *trans,
	struct btrfs_root *root,
	u64 objectid, u64 offset,
	char *data, size_t len)
	{
	int ret;
	struct btrfs_key file_key;
	struct btrfs_key found_key;
	struct btrfs_path *path;
	struct btrfs_csum_item *item;
	struct extent_buffer *leaf = NULL;
	u64 csum_offset;
	u32 csum_result = ~(u32)0;

	path = btrfs_alloc_path();
	BUG_ON(!path);

	file_key.objectid = objectid;
	file_key.offset = offset;
	btrfs_set_key_type(&file_key, BTRFS_CSUM_ITEM_KEY);

	item = btrfs_lookup_csum(trans, root, path, objectid, offset, 1);
	if (!IS_ERR(item)) {
	leaf = path->nodes[0];
	goto found;
	}
	ret = PTR_ERR(item);
	if (ret == -EFBIG) {
	u32 item_size;
	/* we found one, but it isn't big enough yet */
	leaf = path->nodes[0];
	item_size = btrfs_item_size_nr(leaf, path->slots[0]);
	if ((item_size / BTRFS_CRC32_SIZE) >= MAX_CSUM_ITEMS(root)) {
	/* already at max size, make a new one */
	goto insert;
	}
	} else {
	/* we didn't find a csum item, insert one */
	goto insert;
	}

	/*
	* at this point, we know the tree has an item, but it isn't big
	* enough yet to put our csum in. Grow it
	*/
	btrfs_release_path(root, path);
	ret = btrfs_search_slot(trans, root, &file_key, path,
	BTRFS_CRC32_SIZE, 1);
	if (ret < 0)
	goto fail;
	if (ret == 0) {
	BUG();
	}
	if (path->slots[0] == 0) {
	goto insert;
	}
	path->slots[0]--;
	leaf = path->nodes[0];
	btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
	csum_offset = (offset - found_key.offset) >>
	root->fs_info->sb->s_blocksize_bits;
	if (btrfs_key_type(&found_key) != BTRFS_CSUM_ITEM_KEY \|\|
	found_key.objectid != objectid \|\|
	csum_offset >= MAX_CSUM_ITEMS(root)) {
	goto insert;
	}
	if (csum_offset >= btrfs_item_size_nr(leaf, path->slots[0]) /
	BTRFS_CRC32_SIZE) {
	u32 diff = (csum_offset + 1) * BTRFS_CRC32_SIZE;
	diff = diff - btrfs_item_size_nr(leaf, path->slots[0]);
	if (diff != BTRFS_CRC32_SIZE)
	goto insert;
	ret = btrfs_extend_item(trans, root, path, diff);
	BUG_ON(ret);
	goto csum;
	}

	insert:
	btrfs_release_path(root, path);
	csum_offset = 0;
	ret = btrfs_insert_empty_item(trans, root, path, &file_key,
	BTRFS_CRC32_SIZE);
	if (ret < 0)
	goto fail;
	if (ret != 0) {
	WARN_ON(1);
	goto fail;
	}
	csum:
	leaf = path->nodes[0];
	item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_csum_item);
	ret = 0;
	item = (struct btrfs_csum_item )((unsigned char )item +
	csum_offset * BTRFS_CRC32_SIZE);
	found:
	csum_result = btrfs_csum_data(root, data, csum_result, len);
	btrfs_csum_final(csum_result, (char *)&csum_result);
	write_extent_buffer(leaf, &csum_result, (unsigned long)item,
	BTRFS_CRC32_SIZE);
	btrfs_mark_buffer_dirty(path->nodes[0]);
	fail:
	btrfs_release_path(root, path);
	btrfs_free_path(path);
	return ret;
	}

	int btrfs_csum_truncate(struct btrfs_trans_handle *trans,
	struct btrfs_root root, struct btrfs_path path,
	u64 isize)
	{
	struct btrfs_key key;
	struct extent_buffer *leaf = path->nodes[0];
	int slot = path->slots[0];
	int ret;
	u32 new_item_size;
	u64 new_item_span;
	u64 blocks;

	btrfs_item_key_to_cpu(leaf, &key, slot);
	if (isize <= key.offset)
	return 0;
	new_item_span = isize - key.offset;
	blocks = (new_item_span + root->sectorsize - 1) >>
	root->fs_info->sb->s_blocksize_bits;
	new_item_size = blocks * BTRFS_CRC32_SIZE;
	if (new_item_size >= btrfs_item_size_nr(leaf, slot))
	return 0;
	ret = btrfs_truncate_item(trans, root, path, new_item_size);
	BUG_ON(ret);
	return ret;
	}