[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 disk_offset, u64 disk_num_bytes,
			     u64 num_bytes, u64 offset)
{
	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, disk_offset);
	btrfs_set_file_extent_disk_num_bytes(leaf, item, disk_num_bytes);
	btrfs_set_file_extent_offset(leaf, item, offset);
	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, struct btrfs_ordered_sum **sums_ret)
{
	struct btrfs_ordered_sum *sums;
	struct btrfs_sector_sum *sector_sum;
	char *data;
	struct bio_vec *bvec = bio->bi_io_vec;
	int bio_index = 0;

	WARN_ON(bio->bi_vcnt <= 0);
	sums = kzalloc(btrfs_ordered_sum_size(root, bio->bi_size), GFP_NOFS);
	if (!sums)
		return -ENOMEM;
	*sums_ret = sums;
	sector_sum = &sums->sums;
	sums->file_offset = page_offset(bvec->bv_page);
	sums->len = bio->bi_size;
	INIT_LIST_HEAD(&sums->list);

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

int btrfs_csum_file_blocks(struct btrfs_trans_handle *trans,
			   struct btrfs_root *root, struct inode *inode,
			   struct btrfs_ordered_sum *sums)
{
	u64 objectid = inode->i_ino;
	u64 offset;
	int ret;
	struct btrfs_key file_key;
	struct btrfs_key found_key;
	u64 next_offset;
	u64 total_bytes = 0;
	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;
	struct btrfs_sector_sum *sector_sum;
	u32 nritems;
	u32 ins_size;
	char *eb_map;
	char *eb_token;
	unsigned long map_len;
	unsigned long map_start;

	path = btrfs_alloc_path();
	BUG_ON(!path);
	sector_sum = &sums->sums;
again:
	next_offset = (u64)-1;
	found_next = 0;
	offset = sector_sum->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_sector:

	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)),
		       &sector_sum->sum, BTRFS_CRC32_SIZE);
	} else {
		write_extent_buffer(leaf, &sector_sum->sum,
				    (unsigned long)item, BTRFS_CRC32_SIZE);
	}
	total_bytes += root->sectorsize;
	sector_sum++;
	if (total_bytes < sums->len) {
		item = (struct btrfs_csum_item *)((char *)item +
						  BTRFS_CRC32_SIZE);
		if (item < item_end && offset + PAGE_CACHE_SIZE ==
		    sector_sum->offset) {
			    offset = sector_sum->offset;
			goto next_sector;
		}
	}
	if (eb_token) {
		unmap_extent_buffer(leaf, eb_token, KM_USER1);
		eb_token = NULL;
	}
	btrfs_mark_buffer_dirty(path->nodes[0]);
	if (total_bytes < sums->len) {
		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,
f2eb0a24 SW	31	struct btrfs_root *root,
	32	u64 objectid, u64 pos,
	33	u64 disk_offset, u64 disk_num_bytes,
	34	u64 num_bytes, u64 offset)
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);
f2eb0a24	56	btrfs_set_file_extent_disk_bytenr(leaf, item, disk_offset);
db94535d	57	btrfs_set_file_extent_disk_num_bytes(leaf, item, disk_num_bytes);
f2eb0a24	58	btrfs_set_file_extent_offset(leaf, item, offset);
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	137	int btrfs_csum_one_bio(struct btrfs_root *root,
e6dcd2dc	138	struct bio bio, struct btrfs_ordered_sum *sums_ret)
e015640f	139	{
e6dcd2dc CM	140	struct btrfs_ordered_sum *sums;
e6dcd2dc CM	141	struct btrfs_sector_sum *sector_sum;
e015640f CM	142	char *data;
	143	struct bio_vec *bvec = bio->bi_io_vec;
	144	int bio_index = 0;
	145
e6dcd2dc CM	146	WARN_ON(bio->bi_vcnt <= 0);
e6dcd2dc CM	147	sums = kzalloc(btrfs_ordered_sum_size(root, bio->bi_size), GFP_NOFS);
e015640f CM	148	if (!sums)
e015640f CM	149	return -ENOMEM;
e6dcd2dc CM	150	*sums_ret = sums;
	151	sector_sum = &sums->sums;
	152	sums->file_offset = page_offset(bvec->bv_page);
	153	sums->len = bio->bi_size;
	154	INIT_LIST_HEAD(&sums->list);
e015640f CM	155
	156	while(bio_index < bio->bi_vcnt) {
	157	data = kmap_atomic(bvec->bv_page, KM_USER0);
e6dcd2dc CM	158	sector_sum->sum = ~(u32)0;
	159	sector_sum->sum = btrfs_csum_data(root,
	160	data + bvec->bv_offset,
	161	sector_sum->sum,
	162	bvec->bv_len);
e015640f	163	kunmap_atomic(data, KM_USER0);
e6dcd2dc CM	164	btrfs_csum_final(sector_sum->sum,
	165	(char *)&sector_sum->sum);
	166	sector_sum->offset = page_offset(bvec->bv_page) +
	167	bvec->bv_offset;
	168	sector_sum++;
e015640f CM	169	bio_index++;
	170	bvec++;
	171	}
	172	return 0;
	173	}
	174
065631f6 CM	175	int btrfs_csum_file_blocks(struct btrfs_trans_handle *trans,
065631f6 CM	176	struct btrfs_root root, struct inode inode,
e6dcd2dc	177	struct btrfs_ordered_sum *sums)
f254e52c	178	{
065631f6 CM	179	u64 objectid = inode->i_ino;
065631f6 CM	180	u64 offset;
f254e52c CM	181	int ret;
f254e52c CM	182	struct btrfs_key file_key;
6567e837	183	struct btrfs_key found_key;
065631f6	184	u64 next_offset;
e6dcd2dc	185	u64 total_bytes = 0;
065631f6	186	int found_next;
5caf2a00	187	struct btrfs_path *path;
f254e52c	188	struct btrfs_csum_item *item;
065631f6	189	struct btrfs_csum_item *item_end;
ff79f819	190	struct extent_buffer *leaf = NULL;
6567e837	191	u64 csum_offset;
e6dcd2dc	192	struct btrfs_sector_sum *sector_sum;
f578d4bd CM	193	u32 nritems;
f578d4bd CM	194	u32 ins_size;
6e92f5e6 CM	195	char *eb_map;
	196	char *eb_token;
	197	unsigned long map_len;
	198	unsigned long map_start;
	199
5caf2a00 CM	200	path = btrfs_alloc_path();
5caf2a00 CM	201	BUG_ON(!path);
e6dcd2dc	202	sector_sum = &sums->sums;
065631f6 CM	203	again:
	204	next_offset = (u64)-1;
	205	found_next = 0;
e6dcd2dc	206	offset = sector_sum->offset;
f254e52c CM	207	file_key.objectid = objectid;
f254e52c CM	208	file_key.offset = offset;
f254e52c	209	btrfs_set_key_type(&file_key, BTRFS_CSUM_ITEM_KEY);
a429e513 CM	210
a429e513 CM	211	item = btrfs_lookup_csum(trans, root, path, objectid, offset, 1);
ff79f819 CM	212	if (!IS_ERR(item)) {
ff79f819 CM	213	leaf = path->nodes[0];
a429e513	214	goto found;
ff79f819	215	}
a429e513 CM	216	ret = PTR_ERR(item);
	217	if (ret == -EFBIG) {
	218	u32 item_size;
	219	/* we found one, but it isn't big enough yet */
5f39d397 CM	220	leaf = path->nodes[0];
5f39d397 CM	221	item_size = btrfs_item_size_nr(leaf, path->slots[0]);
509659cd	222	if ((item_size / BTRFS_CRC32_SIZE) >= MAX_CSUM_ITEMS(root)) {
a429e513 CM	223	/* already at max size, make a new one */
	224	goto insert;
	225	}
	226	} else {
f578d4bd	227	int slot = path->slots[0] + 1;
a429e513	228	/* we didn't find a csum item, insert one */
f578d4bd CM	229	nritems = btrfs_header_nritems(path->nodes[0]);
	230	if (path->slots[0] >= nritems - 1) {
	231	ret = btrfs_next_leaf(root, path);
b56baf5b	232	if (ret == 1)
f578d4bd	233	found_next = 1;
b56baf5b	234	if (ret != 0)
f578d4bd	235	goto insert;
b56baf5b	236	slot = 0;
f578d4bd CM	237	}
	238	btrfs_item_key_to_cpu(path->nodes[0], &found_key, slot);
	239	if (found_key.objectid != objectid \|\|
	240	found_key.type != BTRFS_CSUM_ITEM_KEY) {
	241	found_next = 1;
	242	goto insert;
	243	}
	244	next_offset = found_key.offset;
	245	found_next = 1;
a429e513 CM	246	goto insert;
	247	}
	248
	249	/*
	250	* at this point, we know the tree has an item, but it isn't big
	251	* enough yet to put our csum in. Grow it
	252	*/
	253	btrfs_release_path(root, path);
6567e837	254	ret = btrfs_search_slot(trans, root, &file_key, path,
509659cd	255	BTRFS_CRC32_SIZE, 1);
6567e837 CM	256	if (ret < 0)
	257	goto fail;
	258	if (ret == 0) {
b18c6685	259	BUG();
6567e837 CM	260	}
6567e837 CM	261	if (path->slots[0] == 0) {
6567e837 CM	262	goto insert;
	263	}
	264	path->slots[0]--;
5f39d397 CM	265	leaf = path->nodes[0];
5f39d397 CM	266	btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
6567e837 CM	267	csum_offset = (offset - found_key.offset) >>
	268	root->fs_info->sb->s_blocksize_bits;
	269	if (btrfs_key_type(&found_key) != BTRFS_CSUM_ITEM_KEY \|\|
	270	found_key.objectid != objectid \|\|
	271	csum_offset >= MAX_CSUM_ITEMS(root)) {
6567e837 CM	272	goto insert;
6567e837 CM	273	}
5f39d397	274	if (csum_offset >= btrfs_item_size_nr(leaf, path->slots[0]) /
509659cd CM	275	BTRFS_CRC32_SIZE) {
509659cd CM	276	u32 diff = (csum_offset + 1) * BTRFS_CRC32_SIZE;
5f39d397	277	diff = diff - btrfs_item_size_nr(leaf, path->slots[0]);
3a686375 CM	278	if (diff != BTRFS_CRC32_SIZE)
3a686375 CM	279	goto insert;
a429e513	280	ret = btrfs_extend_item(trans, root, path, diff);
6567e837 CM	281	BUG_ON(ret);
	282	goto csum;
	283	}
	284
	285	insert:
a429e513	286	btrfs_release_path(root, path);
6567e837	287	csum_offset = 0;
f578d4bd CM	288	if (found_next) {
f578d4bd CM	289	u64 tmp = min((u64)i_size_read(inode), next_offset);
b56baf5b	290	tmp -= offset & ~((u64)root->sectorsize -1);
f578d4bd CM	291	tmp >>= root->fs_info->sb->s_blocksize_bits;
	292	tmp = max((u64)1, tmp);
	293	tmp = min(tmp, (u64)MAX_CSUM_ITEMS(root));
	294	ins_size = BTRFS_CRC32_SIZE * tmp;
	295	} else {
	296	ins_size = BTRFS_CRC32_SIZE;
	297	}
5caf2a00	298	ret = btrfs_insert_empty_item(trans, root, path, &file_key,
f578d4bd	299	ins_size);
54aa1f4d CM	300	if (ret < 0)
54aa1f4d CM	301	goto fail;
a429e513	302	if (ret != 0) {
a429e513	303	WARN_ON(1);
f254e52c	304	goto fail;
a429e513	305	}
6567e837	306	csum:
5f39d397 CM	307	leaf = path->nodes[0];
5f39d397 CM	308	item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_csum_item);
f254e52c	309	ret = 0;
509659cd CM	310	item = (struct btrfs_csum_item )((unsigned char )item +
509659cd CM	311	csum_offset * BTRFS_CRC32_SIZE);
b18c6685	312	found:
065631f6 CM	313	item_end = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_csum_item);
	314	item_end = (struct btrfs_csum_item )((unsigned char )item_end +
	315	btrfs_item_size_nr(leaf, path->slots[0]));
6e92f5e6	316	eb_token = NULL;
e6dcd2dc	317	next_sector:
aadfeb6e	318
6e92f5e6 CM	319	if (!eb_token \|\|
	320	(unsigned long)item + BTRFS_CRC32_SIZE >= map_start + map_len) {
	321	int err;
	322
	323	if (eb_token)
eb20978f	324	unmap_extent_buffer(leaf, eb_token, KM_USER1);
6e92f5e6 CM	325	eb_token = NULL;
	326	err = map_private_extent_buffer(leaf, (unsigned long)item,
	327	BTRFS_CRC32_SIZE,
	328	&eb_token, &eb_map,
eb20978f	329	&map_start, &map_len, KM_USER1);
6e92f5e6 CM	330	if (err)
	331	eb_token = NULL;
	332	}
	333	if (eb_token) {
	334	memcpy(eb_token + ((unsigned long)item & (PAGE_CACHE_SIZE - 1)),
e6dcd2dc	335	&sector_sum->sum, BTRFS_CRC32_SIZE);
6e92f5e6	336	} else {
e6dcd2dc CM	337	write_extent_buffer(leaf, &sector_sum->sum,
e6dcd2dc CM	338	(unsigned long)item, BTRFS_CRC32_SIZE);
6e92f5e6	339	}
e6dcd2dc CM	340	total_bytes += root->sectorsize;
	341	sector_sum++;
	342	if (total_bytes < sums->len) {
6e92f5e6 CM	343	item = (struct btrfs_csum_item )((char )item +
6e92f5e6 CM	344	BTRFS_CRC32_SIZE);
2e1a992e	345	if (item < item_end && offset + PAGE_CACHE_SIZE ==
e6dcd2dc CM	346	sector_sum->offset) {
	347	offset = sector_sum->offset;
	348	goto next_sector;
2e1a992e	349	}
065631f6	350	}
6e92f5e6	351	if (eb_token) {
eb20978f	352	unmap_extent_buffer(leaf, eb_token, KM_USER1);
6e92f5e6 CM	353	eb_token = NULL;
6e92f5e6 CM	354	}
5caf2a00	355	btrfs_mark_buffer_dirty(path->nodes[0]);
e6dcd2dc	356	if (total_bytes < sums->len) {
065631f6 CM	357	btrfs_release_path(root, path);
	358	goto again;
	359	}
f254e52c	360	fail:
5caf2a00	361	btrfs_free_path(path);
f254e52c CM	362	return ret;
	363	}
	364
1de037a4 CM	365	int btrfs_csum_truncate(struct btrfs_trans_handle *trans,
	366	struct btrfs_root root, struct btrfs_path path,
	367	u64 isize)
	368	{
	369	struct btrfs_key key;
5f39d397	370	struct extent_buffer *leaf = path->nodes[0];
1de037a4 CM	371	int slot = path->slots[0];
	372	int ret;
	373	u32 new_item_size;
	374	u64 new_item_span;
	375	u64 blocks;
	376
5f39d397	377	btrfs_item_key_to_cpu(leaf, &key, slot);
1de037a4 CM	378	if (isize <= key.offset)
	379	return 0;
	380	new_item_span = isize - key.offset;
5f39d397	381	blocks = (new_item_span + root->sectorsize - 1) >>
84f54cfa	382	root->fs_info->sb->s_blocksize_bits;
1de037a4	383	new_item_size = blocks * BTRFS_CRC32_SIZE;
5f39d397	384	if (new_item_size >= btrfs_item_size_nr(leaf, slot))
1de037a4	385	return 0;
179e29e4	386	ret = btrfs_truncate_item(trans, root, path, new_item_size, 1);
1de037a4 CM	387	BUG_ON(ret);
	388	return ret;
	389	}
	390