1 files changed, 512 insertions, 0 deletions

diff --git a/fs/btrfs/file-item.c b/fs/btrfs/file-item.c
new file mode 100644
index 000000000000..6dbe88b9d7d4
--- /dev/null
+++ b/fs/btrfs/file-item.c
@@ -0,0 +1,512 @@
+/*
+ * 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_lookup_bio_sums(struct btrfs_root *root, struct inode *inode,
+			  struct bio *bio)
+{
+	u32 sum;
+	struct bio_vec *bvec = bio->bi_io_vec;
+	int bio_index = 0;
+	u64 offset;
+	u64 item_start_offset = 0;
+	u64 item_last_offset = 0;
+	u32 diff;
+	int ret;
+	struct btrfs_path *path;
+	struct btrfs_csum_item *item = NULL;
+	struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
+
+	path = btrfs_alloc_path();
+	if (bio->bi_size > PAGE_CACHE_SIZE * 8)
+		path->reada = 2;
+
+	WARN_ON(bio->bi_vcnt <= 0);
+
+	while(bio_index < bio->bi_vcnt) {
+		offset = page_offset(bvec->bv_page) + bvec->bv_offset;
+		ret = btrfs_find_ordered_sum(inode, offset, &sum);
+		if (ret == 0)
+			goto found;
+
+		if (!item || offset < item_start_offset ||
+		    offset >= item_last_offset) {
+			struct btrfs_key found_key;
+			u32 item_size;
+
+			if (item)
+				btrfs_release_path(root, path);
+			item = btrfs_lookup_csum(NULL, root, path,
+						 inode->i_ino, offset, 0);
+			if (IS_ERR(item)) {
+				ret = PTR_ERR(item);
+				if (ret == -ENOENT || ret == -EFBIG)
+					ret = 0;
+				sum = 0;
+				printk("no csum found for inode %lu start "
+				       "%llu\n", inode->i_ino,
+				       (unsigned long long)offset);
+				item = NULL;
+				goto found;
+			}
+			btrfs_item_key_to_cpu(path->nodes[0], &found_key,
+					      path->slots[0]);
+
+			item_start_offset = found_key.offset;
+			item_size = btrfs_item_size_nr(path->nodes[0],
+						       path->slots[0]);
+			item_last_offset = item_start_offset +
+				(item_size / BTRFS_CRC32_SIZE) *
+				root->sectorsize;
+			item = btrfs_item_ptr(path->nodes[0], path->slots[0],
+					      struct btrfs_csum_item);
+		}
+		/*
+		 * this byte range must be able to fit inside
+		 * a single leaf so it will also fit inside a u32
+		 */
+		diff = offset - item_start_offset;
+		diff = diff / root->sectorsize;
+		diff = diff * BTRFS_CRC32_SIZE;
+
+		read_extent_buffer(path->nodes[0], &sum,
+				   ((unsigned long)item) + diff,
+				   BTRFS_CRC32_SIZE);
+found:
+		set_state_private(io_tree, offset, sum);
+		bio_index++;
+		bvec++;
+	}
+	btrfs_free_path(path);
+	return 0;
+}
+
+int btrfs_csum_one_bio(struct btrfs_root *root, struct inode *inode,
+		       struct bio *bio)
+{
+	struct btrfs_ordered_sum *sums;
+	struct btrfs_sector_sum *sector_sum;
+	struct btrfs_ordered_extent *ordered;
+	char *data;
+	struct bio_vec *bvec = bio->bi_io_vec;
+	int bio_index = 0;
+	unsigned long total_bytes = 0;
+	unsigned long this_sum_bytes = 0;
+	u64 offset;
+
+	WARN_ON(bio->bi_vcnt <= 0);
+	sums = kzalloc(btrfs_ordered_sum_size(root, bio->bi_size), GFP_NOFS);
+	if (!sums)
+		return -ENOMEM;
+
+	sector_sum = sums->sums;
+	sums->file_offset = page_offset(bvec->bv_page) + bvec->bv_offset;
+	sums->len = bio->bi_size;
+	INIT_LIST_HEAD(&sums->list);
+	ordered = btrfs_lookup_ordered_extent(inode, sums->file_offset);
+	BUG_ON(!ordered);
+
+	while(bio_index < bio->bi_vcnt) {
+		offset = page_offset(bvec->bv_page) + bvec->bv_offset;
+		if (offset >= ordered->file_offset + ordered->len ||
+		    offset < ordered->file_offset) {
+			unsigned long bytes_left;
+			sums->len = this_sum_bytes;
+			this_sum_bytes = 0;
+			btrfs_add_ordered_sum(inode, ordered, sums);
+			btrfs_put_ordered_extent(ordered);
+
+			bytes_left = bio->bi_size - total_bytes;
+
+			sums = kzalloc(btrfs_ordered_sum_size(root, bytes_left),
+				       GFP_NOFS);
+			BUG_ON(!sums);
+			sector_sum = sums->sums;
+			sums->len = bytes_left;
+			sums->file_offset = offset;
+			ordered = btrfs_lookup_ordered_extent(inode,
+						      sums->file_offset);
+			BUG_ON(!ordered);
+		}
+
+		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++;
+		total_bytes += bvec->bv_len;
+		this_sum_bytes += bvec->bv_len;
+		bvec++;
+	}
+	this_sum_bytes = 0;
+	btrfs_add_ordered_sum(inode, ordered, sums);
+	btrfs_put_ordered_extent(ordered);
+	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);
+
+	mutex_lock(&BTRFS_I(inode)->csum_mutex);
+	item = btrfs_lookup_csum(trans, root, path, objectid, offset, 1);
+	if (!IS_ERR(item)) {
+		leaf = path->nodes[0];
+		ret = 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_unlock;
+	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_unlock;
+	if (ret != 0) {
+		WARN_ON(1);
+		goto fail_unlock;
+	}
+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;
+	mutex_unlock(&BTRFS_I(inode)->csum_mutex);
+	cond_resched();
+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]);
+	cond_resched();
+	if (total_bytes < sums->len) {
+		btrfs_release_path(root, path);
+		goto again;
+	}
+out:
+	btrfs_free_path(path);
+	return ret;
+
+fail_unlock:
+	mutex_unlock(&BTRFS_I(inode)->csum_mutex);
+	goto out;
+}
+
+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;
+}