[mirror_ubuntu-bionic-kernel.git] / fs / btrfs / file-item.c

/*
 * 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 <linux/bio.h>
#include <linux/pagemap.h>
#include <linux/highmem.h>
#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_one_bio(struct btrfs_root *root,
		       struct bio *bio, char **sums_ret)
{
	u32 *sums;
	char *data;
	struct bio_vec *bvec = bio->bi_io_vec;
	int bio_index = 0;

	sums = kmalloc(bio->bi_vcnt * BTRFS_CRC32_SIZE, GFP_NOFS);
	if (!sums)
		return -ENOMEM;
	*sums_ret = (char *)sums;

	while(bio_index < bio->bi_vcnt) {
		data = kmap_atomic(bvec->bv_page, KM_USER0);
		*sums = ~(u32)0;
		*sums = btrfs_csum_data(root, data + bvec->bv_offset,
					*sums, bvec->bv_len);
		kunmap_atomic(data, KM_USER0);
		btrfs_csum_final(*sums, (char *)sums);
		sums++;
		bio_index++;
		bvec++;
	}
	return 0;
}

int btrfs_csum_file_blocks(struct btrfs_trans_handle *trans,
			   struct btrfs_root *root, struct inode *inode,
			   struct bio *bio, char *sums)
{
	u64 objectid = inode->i_ino;
	u64 offset;
	int ret;
	struct btrfs_key file_key;
	struct btrfs_key found_key;
	u64 next_offset;
	int found_next;
	struct btrfs_path *path;
	struct btrfs_csum_item *item;
	struct btrfs_csum_item *item_end;
	struct extent_buffer *leaf = NULL;
	u64 csum_offset;
	u32 *sums32 = (u32 *)sums;
	u32 nritems;
	u32 ins_size;
	int bio_index = 0;
	struct bio_vec *bvec = bio->bi_io_vec;
	char *eb_map;
	char *eb_token;
	unsigned long map_len;
	unsigned long map_start;

	path = btrfs_alloc_path();
	BUG_ON(!path);
again:
	next_offset = (u64)-1;
	found_next = 0;
	offset = page_offset(bvec->bv_page) + bvec->bv_offset;
	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 {
		int slot = path->slots[0] + 1;
		/* we didn't find a csum item, insert one */
		nritems = btrfs_header_nritems(path->nodes[0]);
		if (path->slots[0] >= nritems - 1) {
			ret = btrfs_next_leaf(root, path);
			if (ret == 1)
				found_next = 1;
			if (ret != 0)
				goto insert;
			slot = 0;
		}
		btrfs_item_key_to_cpu(path->nodes[0], &found_key, slot);
		if (found_key.objectid != objectid ||
		    found_key.type != BTRFS_CSUM_ITEM_KEY) {
			found_next = 1;
			goto insert;
		}
		next_offset = found_key.offset;
		found_next = 1;
		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;
	if (found_next) {
		u64 tmp = min((u64)i_size_read(inode), next_offset);
		tmp -= offset & ~((u64)root->sectorsize -1);
		tmp >>= root->fs_info->sb->s_blocksize_bits;
		tmp = max((u64)1, tmp);
		tmp = min(tmp, (u64)MAX_CSUM_ITEMS(root));
		ins_size = BTRFS_CRC32_SIZE * tmp;
	} else {
		ins_size = BTRFS_CRC32_SIZE;
	}
	ret = btrfs_insert_empty_item(trans, root, path, &file_key,
				      ins_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:
	item_end = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_csum_item);
	item_end = (struct btrfs_csum_item *)((unsigned char *)item_end +
				      btrfs_item_size_nr(leaf, path->slots[0]));
	eb_token = NULL;
next_bvec:

	if (!eb_token ||
	   (unsigned long)item  + BTRFS_CRC32_SIZE >= map_start + map_len) {
		int err;

		if (eb_token)
			unmap_extent_buffer(leaf, eb_token, KM_USER1);
		eb_token = NULL;
		err = map_private_extent_buffer(leaf, (unsigned long)item,
						BTRFS_CRC32_SIZE,
						&eb_token, &eb_map,
						&map_start, &map_len, KM_USER1);
		if (err)
			eb_token = NULL;
	}
	if (eb_token) {
		memcpy(eb_token + ((unsigned long)item & (PAGE_CACHE_SIZE - 1)),
		       sums32, BTRFS_CRC32_SIZE);
	} else {
		write_extent_buffer(leaf, sums32, (unsigned long)item,
				    BTRFS_CRC32_SIZE);
	}
	bio_index++;
	bvec++;
	sums32++;
	if (bio_index < bio->bi_vcnt) {
		item = (struct btrfs_csum_item *)((char *)item +
						  BTRFS_CRC32_SIZE);
		if (item < item_end && offset + PAGE_CACHE_SIZE ==
		    page_offset(bvec->bv_page)) {
			offset = page_offset(bvec->bv_page);
			goto next_bvec;
		}
	}
	if (eb_token) {
		unmap_extent_buffer(leaf, eb_token, KM_USER1);
		eb_token = NULL;
	}
	btrfs_mark_buffer_dirty(path->nodes[0]);
	if (bio_index < bio->bi_vcnt) {
		btrfs_release_path(root, path);
		goto again;
	}
fail:
	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, 1);
	BUG_ON(ret);
	return ret;
}
Commit	Line	Data
6cbd5570 CM	1	/*
	2	* Copyright (C) 2007 Oracle. All rights reserved.
	3	*
	4	* This program is free software; you can redistribute it and/or
	5	* modify it under the terms of the GNU General Public
	6	* License v2 as published by the Free Software Foundation.
	7	*
	8	* This program is distributed in the hope that it will be useful,
	9	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	10	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	11	* General Public License for more details.
	12	*
	13	* You should have received a copy of the GNU General Public
	14	* License along with this program; if not, write to the
	15	* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
	16	* Boston, MA 021110-1307, USA.
	17	*/
	18
065631f6 CM	19	#include <linux/bio.h>
	20	#include <linux/pagemap.h>
	21	#include <linux/highmem.h>
1e1d2701	22	#include "ctree.h"
dee26a9f	23	#include "disk-io.h"
9f5fae2f	24	#include "transaction.h"
1de037a4	25	#include "print-tree.h"
1e1d2701	26
6567e837	27	#define MAX_CSUM_ITEMS(r) ((((BTRFS_LEAF_DATA_SIZE(r) - \
509659cd CM	28	sizeof(struct btrfs_item) * 2) / \
509659cd CM	29	BTRFS_CRC32_SIZE) - 1))
b18c6685	30	int btrfs_insert_file_extent(struct btrfs_trans_handle *trans,
dee26a9f	31	struct btrfs_root *root,
b18c6685	32	u64 objectid, u64 pos,
db94535d CM	33	u64 offset, u64 disk_num_bytes,
db94535d CM	34	u64 num_bytes)
9f5fae2f	35	{
dee26a9f CM	36	int ret = 0;
	37	struct btrfs_file_extent_item *item;
	38	struct btrfs_key file_key;
5caf2a00	39	struct btrfs_path *path;
5f39d397	40	struct extent_buffer *leaf;
dee26a9f	41
5caf2a00 CM	42	path = btrfs_alloc_path();
5caf2a00 CM	43	BUG_ON(!path);
dee26a9f	44	file_key.objectid = objectid;
b18c6685	45	file_key.offset = pos;
dee26a9f CM	46	btrfs_set_key_type(&file_key, BTRFS_EXTENT_DATA_KEY);
dee26a9f CM	47
5caf2a00	48	ret = btrfs_insert_empty_item(trans, root, path, &file_key,
dee26a9f	49	sizeof(*item));
54aa1f4d CM	50	if (ret < 0)
54aa1f4d CM	51	goto out;
9773a788	52	BUG_ON(ret);
5f39d397 CM	53	leaf = path->nodes[0];
5f39d397 CM	54	item = btrfs_item_ptr(leaf, path->slots[0],
dee26a9f	55	struct btrfs_file_extent_item);
db94535d CM	56	btrfs_set_file_extent_disk_bytenr(leaf, item, offset);
db94535d CM	57	btrfs_set_file_extent_disk_num_bytes(leaf, item, disk_num_bytes);
5f39d397	58	btrfs_set_file_extent_offset(leaf, item, 0);
db94535d	59	btrfs_set_file_extent_num_bytes(leaf, item, num_bytes);
5f39d397 CM	60	btrfs_set_file_extent_generation(leaf, item, trans->transid);
	61	btrfs_set_file_extent_type(leaf, item, BTRFS_FILE_EXTENT_REG);
	62	btrfs_mark_buffer_dirty(leaf);
54aa1f4d	63	out:
5caf2a00	64	btrfs_free_path(path);
54aa1f4d	65	return ret;
9f5fae2f	66	}
dee26a9f	67
b18c6685 CM	68	struct btrfs_csum_item btrfs_lookup_csum(struct btrfs_trans_handle trans,
	69	struct btrfs_root *root,
	70	struct btrfs_path *path,
	71	u64 objectid, u64 offset,
	72	int cow)
6567e837 CM	73	{
	74	int ret;
	75	struct btrfs_key file_key;
	76	struct btrfs_key found_key;
	77	struct btrfs_csum_item *item;
5f39d397	78	struct extent_buffer *leaf;
6567e837	79	u64 csum_offset = 0;
a429e513	80	int csums_in_item;
6567e837 CM	81
	82	file_key.objectid = objectid;
	83	file_key.offset = offset;
6567e837	84	btrfs_set_key_type(&file_key, BTRFS_CSUM_ITEM_KEY);
b18c6685	85	ret = btrfs_search_slot(trans, root, &file_key, path, 0, cow);
6567e837 CM	86	if (ret < 0)
6567e837 CM	87	goto fail;
5f39d397	88	leaf = path->nodes[0];
6567e837 CM	89	if (ret > 0) {
6567e837 CM	90	ret = 1;
70b2befd	91	if (path->slots[0] == 0)
6567e837 CM	92	goto fail;
6567e837 CM	93	path->slots[0]--;
5f39d397	94	btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
6567e837 CM	95	if (btrfs_key_type(&found_key) != BTRFS_CSUM_ITEM_KEY \|\|
	96	found_key.objectid != objectid) {
	97	goto fail;
	98	}
	99	csum_offset = (offset - found_key.offset) >>
	100	root->fs_info->sb->s_blocksize_bits;
5f39d397	101	csums_in_item = btrfs_item_size_nr(leaf, path->slots[0]);
509659cd	102	csums_in_item /= BTRFS_CRC32_SIZE;
a429e513 CM	103
	104	if (csum_offset >= csums_in_item) {
	105	ret = -EFBIG;
6567e837 CM	106	goto fail;
	107	}
	108	}
	109	item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_csum_item);
509659cd CM	110	item = (struct btrfs_csum_item )((unsigned char )item +
509659cd CM	111	csum_offset * BTRFS_CRC32_SIZE);
6567e837 CM	112	return item;
	113	fail:
	114	if (ret > 0)
b18c6685	115	ret = -ENOENT;
6567e837 CM	116	return ERR_PTR(ret);
	117	}
	118
	119
dee26a9f CM	120	int btrfs_lookup_file_extent(struct btrfs_trans_handle *trans,
	121	struct btrfs_root *root,
	122	struct btrfs_path *path, u64 objectid,
9773a788	123	u64 offset, int mod)
dee26a9f CM	124	{
	125	int ret;
	126	struct btrfs_key file_key;
	127	int ins_len = mod < 0 ? -1 : 0;
	128	int cow = mod != 0;
	129
	130	file_key.objectid = objectid;
70b2befd	131	file_key.offset = offset;
dee26a9f CM	132	btrfs_set_key_type(&file_key, BTRFS_EXTENT_DATA_KEY);
	133	ret = btrfs_search_slot(trans, root, &file_key, path, ins_len, cow);
	134	return ret;
	135	}
f254e52c	136
e015640f CM	137	int btrfs_csum_one_bio(struct btrfs_root *root,
	138	struct bio bio, char *sums_ret)
	139	{
	140	u32 *sums;
	141	char *data;
	142	struct bio_vec *bvec = bio->bi_io_vec;
	143	int bio_index = 0;
	144
	145	sums = kmalloc(bio->bi_vcnt * BTRFS_CRC32_SIZE, GFP_NOFS);
	146	if (!sums)
	147	return -ENOMEM;
	148	sums_ret = (char )sums;
	149
	150	while(bio_index < bio->bi_vcnt) {
	151	data = kmap_atomic(bvec->bv_page, KM_USER0);
	152	*sums = ~(u32)0;
	153	*sums = btrfs_csum_data(root, data + bvec->bv_offset,
	154	*sums, bvec->bv_len);
	155	kunmap_atomic(data, KM_USER0);
	156	btrfs_csum_final(sums, (char )sums);
	157	sums++;
	158	bio_index++;
	159	bvec++;
	160	}
	161	return 0;
	162	}
	163
065631f6 CM	164	int btrfs_csum_file_blocks(struct btrfs_trans_handle *trans,
065631f6 CM	165	struct btrfs_root root, struct inode inode,
e015640f	166	struct bio bio, char sums)
f254e52c	167	{
065631f6 CM	168	u64 objectid = inode->i_ino;
065631f6 CM	169	u64 offset;
f254e52c CM	170	int ret;
f254e52c CM	171	struct btrfs_key file_key;
6567e837	172	struct btrfs_key found_key;
065631f6 CM	173	u64 next_offset;
065631f6 CM	174	int found_next;
5caf2a00	175	struct btrfs_path *path;
f254e52c	176	struct btrfs_csum_item *item;
065631f6	177	struct btrfs_csum_item *item_end;
ff79f819	178	struct extent_buffer *leaf = NULL;
6567e837	179	u64 csum_offset;
e015640f	180	u32 sums32 = (u32 )sums;
f578d4bd CM	181	u32 nritems;
f578d4bd CM	182	u32 ins_size;
065631f6 CM	183	int bio_index = 0;
065631f6 CM	184	struct bio_vec *bvec = bio->bi_io_vec;
6e92f5e6 CM	185	char *eb_map;
	186	char *eb_token;
	187	unsigned long map_len;
	188	unsigned long map_start;
	189
5caf2a00 CM	190	path = btrfs_alloc_path();
5caf2a00 CM	191	BUG_ON(!path);
065631f6 CM	192	again:
	193	next_offset = (u64)-1;
	194	found_next = 0;
	195	offset = page_offset(bvec->bv_page) + bvec->bv_offset;
f254e52c CM	196	file_key.objectid = objectid;
f254e52c CM	197	file_key.offset = offset;
f254e52c	198	btrfs_set_key_type(&file_key, BTRFS_CSUM_ITEM_KEY);
a429e513 CM	199
a429e513 CM	200	item = btrfs_lookup_csum(trans, root, path, objectid, offset, 1);
ff79f819 CM	201	if (!IS_ERR(item)) {
ff79f819 CM	202	leaf = path->nodes[0];
a429e513	203	goto found;
ff79f819	204	}
a429e513 CM	205	ret = PTR_ERR(item);
	206	if (ret == -EFBIG) {
	207	u32 item_size;
	208	/* we found one, but it isn't big enough yet */
5f39d397 CM	209	leaf = path->nodes[0];
5f39d397 CM	210	item_size = btrfs_item_size_nr(leaf, path->slots[0]);
509659cd	211	if ((item_size / BTRFS_CRC32_SIZE) >= MAX_CSUM_ITEMS(root)) {
a429e513 CM	212	/* already at max size, make a new one */
	213	goto insert;
	214	}
	215	} else {
f578d4bd	216	int slot = path->slots[0] + 1;
a429e513	217	/* we didn't find a csum item, insert one */
f578d4bd CM	218	nritems = btrfs_header_nritems(path->nodes[0]);
	219	if (path->slots[0] >= nritems - 1) {
	220	ret = btrfs_next_leaf(root, path);
b56baf5b	221	if (ret == 1)
f578d4bd	222	found_next = 1;
b56baf5b	223	if (ret != 0)
f578d4bd	224	goto insert;
b56baf5b	225	slot = 0;
f578d4bd CM	226	}
	227	btrfs_item_key_to_cpu(path->nodes[0], &found_key, slot);
	228	if (found_key.objectid != objectid \|\|
	229	found_key.type != BTRFS_CSUM_ITEM_KEY) {
	230	found_next = 1;
	231	goto insert;
	232	}
	233	next_offset = found_key.offset;
	234	found_next = 1;
a429e513 CM	235	goto insert;
	236	}
	237
	238	/*
	239	* at this point, we know the tree has an item, but it isn't big
	240	* enough yet to put our csum in. Grow it
	241	*/
	242	btrfs_release_path(root, path);
6567e837	243	ret = btrfs_search_slot(trans, root, &file_key, path,
509659cd	244	BTRFS_CRC32_SIZE, 1);
6567e837 CM	245	if (ret < 0)
	246	goto fail;
	247	if (ret == 0) {
b18c6685	248	BUG();
6567e837 CM	249	}
6567e837 CM	250	if (path->slots[0] == 0) {
6567e837 CM	251	goto insert;
	252	}
	253	path->slots[0]--;
5f39d397 CM	254	leaf = path->nodes[0];
5f39d397 CM	255	btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
6567e837 CM	256	csum_offset = (offset - found_key.offset) >>
	257	root->fs_info->sb->s_blocksize_bits;
	258	if (btrfs_key_type(&found_key) != BTRFS_CSUM_ITEM_KEY \|\|
	259	found_key.objectid != objectid \|\|
	260	csum_offset >= MAX_CSUM_ITEMS(root)) {
6567e837 CM	261	goto insert;
6567e837 CM	262	}
5f39d397	263	if (csum_offset >= btrfs_item_size_nr(leaf, path->slots[0]) /
509659cd CM	264	BTRFS_CRC32_SIZE) {
509659cd CM	265	u32 diff = (csum_offset + 1) * BTRFS_CRC32_SIZE;
5f39d397	266	diff = diff - btrfs_item_size_nr(leaf, path->slots[0]);
3a686375 CM	267	if (diff != BTRFS_CRC32_SIZE)
3a686375 CM	268	goto insert;
a429e513	269	ret = btrfs_extend_item(trans, root, path, diff);
6567e837 CM	270	BUG_ON(ret);
	271	goto csum;
	272	}
	273
	274	insert:
a429e513	275	btrfs_release_path(root, path);
6567e837	276	csum_offset = 0;
f578d4bd CM	277	if (found_next) {
f578d4bd CM	278	u64 tmp = min((u64)i_size_read(inode), next_offset);
b56baf5b	279	tmp -= offset & ~((u64)root->sectorsize -1);
f578d4bd CM	280	tmp >>= root->fs_info->sb->s_blocksize_bits;
	281	tmp = max((u64)1, tmp);
	282	tmp = min(tmp, (u64)MAX_CSUM_ITEMS(root));
	283	ins_size = BTRFS_CRC32_SIZE * tmp;
	284	} else {
	285	ins_size = BTRFS_CRC32_SIZE;
	286	}
5caf2a00	287	ret = btrfs_insert_empty_item(trans, root, path, &file_key,
f578d4bd	288	ins_size);
54aa1f4d CM	289	if (ret < 0)
54aa1f4d CM	290	goto fail;
a429e513	291	if (ret != 0) {
a429e513	292	WARN_ON(1);
f254e52c	293	goto fail;
a429e513	294	}
6567e837	295	csum:
5f39d397 CM	296	leaf = path->nodes[0];
5f39d397 CM	297	item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_csum_item);
f254e52c	298	ret = 0;
509659cd CM	299	item = (struct btrfs_csum_item )((unsigned char )item +
509659cd CM	300	csum_offset * BTRFS_CRC32_SIZE);
b18c6685	301	found:
065631f6 CM	302	item_end = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_csum_item);
	303	item_end = (struct btrfs_csum_item )((unsigned char )item_end +
	304	btrfs_item_size_nr(leaf, path->slots[0]));
6e92f5e6	305	eb_token = NULL;
065631f6	306	next_bvec:
aadfeb6e	307
6e92f5e6 CM	308	if (!eb_token \|\|
	309	(unsigned long)item + BTRFS_CRC32_SIZE >= map_start + map_len) {
	310	int err;
	311
	312	if (eb_token)
eb20978f	313	unmap_extent_buffer(leaf, eb_token, KM_USER1);
6e92f5e6 CM	314	eb_token = NULL;
	315	err = map_private_extent_buffer(leaf, (unsigned long)item,
	316	BTRFS_CRC32_SIZE,
	317	&eb_token, &eb_map,
eb20978f	318	&map_start, &map_len, KM_USER1);
6e92f5e6 CM	319	if (err)
	320	eb_token = NULL;
	321	}
	322	if (eb_token) {
	323	memcpy(eb_token + ((unsigned long)item & (PAGE_CACHE_SIZE - 1)),
e015640f	324	sums32, BTRFS_CRC32_SIZE);
6e92f5e6	325	} else {
e015640f	326	write_extent_buffer(leaf, sums32, (unsigned long)item,
6e92f5e6 CM	327	BTRFS_CRC32_SIZE);
6e92f5e6 CM	328	}
065631f6 CM	329	bio_index++;
065631f6 CM	330	bvec++;
e015640f	331	sums32++;
065631f6	332	if (bio_index < bio->bi_vcnt) {
6e92f5e6 CM	333	item = (struct btrfs_csum_item )((char )item +
6e92f5e6 CM	334	BTRFS_CRC32_SIZE);
2e1a992e CM	335	if (item < item_end && offset + PAGE_CACHE_SIZE ==
	336	page_offset(bvec->bv_page)) {
	337	offset = page_offset(bvec->bv_page);
065631f6	338	goto next_bvec;
2e1a992e	339	}
065631f6	340	}
6e92f5e6	341	if (eb_token) {
eb20978f	342	unmap_extent_buffer(leaf, eb_token, KM_USER1);
6e92f5e6 CM	343	eb_token = NULL;
6e92f5e6 CM	344	}
5caf2a00	345	btrfs_mark_buffer_dirty(path->nodes[0]);
065631f6 CM	346	if (bio_index < bio->bi_vcnt) {
	347	btrfs_release_path(root, path);
	348	goto again;
	349	}
f254e52c	350	fail:
5caf2a00	351	btrfs_free_path(path);
f254e52c CM	352	return ret;
	353	}
	354
1de037a4 CM	355	int btrfs_csum_truncate(struct btrfs_trans_handle *trans,
	356	struct btrfs_root root, struct btrfs_path path,
	357	u64 isize)
	358	{
	359	struct btrfs_key key;
5f39d397	360	struct extent_buffer *leaf = path->nodes[0];
1de037a4 CM	361	int slot = path->slots[0];
	362	int ret;
	363	u32 new_item_size;
	364	u64 new_item_span;
	365	u64 blocks;
	366
5f39d397	367	btrfs_item_key_to_cpu(leaf, &key, slot);
1de037a4 CM	368	if (isize <= key.offset)
	369	return 0;
	370	new_item_span = isize - key.offset;
5f39d397	371	blocks = (new_item_span + root->sectorsize - 1) >>
84f54cfa	372	root->fs_info->sb->s_blocksize_bits;
1de037a4	373	new_item_size = blocks * BTRFS_CRC32_SIZE;
5f39d397	374	if (new_item_size >= btrfs_item_size_nr(leaf, slot))
1de037a4	375	return 0;
179e29e4	376	ret = btrfs_truncate_item(trans, root, path, new_item_size, 1);
1de037a4 CM	377	BUG_ON(ret);
	378	return ret;
	379	}
	380