--- /dev/null
+/*
+ * Copyright (C) 2010 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <stdlib.h>
+#include <stdio.h>
+
+#include "ext4_utils.h"
+#include "ext4.h"
+#include "ext4_extents.h"
+#include "backed_block.h"
+
+#include "extent.h"
+
+/* Creates data buffers for the first backing_len bytes of a block allocation
+ and queues them to be written */
+static u8 *extent_create_backing(struct block_allocation *alloc,
+ u64 backing_len)
+{
+ u8 *data = calloc(backing_len, 1);
+ if (!data)
+ critical_error_errno("calloc");
+
+ u8 *ptr = data;
+ for (; alloc != NULL && backing_len > 0; get_next_region(alloc)) {
+ u32 region_block;
+ u32 region_len;
+ u32 len;
+ get_region(alloc, ®ion_block, ®ion_len);
+
+ len = min(region_len * info.block_size, backing_len);
+
+ queue_data_block(ptr, len, region_block);
+ ptr += len;
+ backing_len -= len;
+ }
+
+ return data;
+}
+
+/* Queues each chunk of a file to be written to contiguous data block
+ regions */
+static void extent_create_backing_file(struct block_allocation *alloc,
+ u64 backing_len, const char *filename)
+{
+ off_t offset = 0;
+ for (; alloc != NULL && backing_len > 0; get_next_region(alloc)) {
+ u32 region_block;
+ u32 region_len;
+ u32 len;
+ get_region(alloc, ®ion_block, ®ion_len);
+
+ len = min(region_len * info.block_size, backing_len);
+
+ queue_data_file(filename, offset, len, region_block);
+ offset += len;
+ backing_len -= len;
+ }
+}
+
+static struct block_allocation *do_inode_allocate_extents(
+ struct ext4_inode *inode, u64 len)
+{
+ u32 block_len = DIV_ROUND_UP(len, info.block_size);
+ struct block_allocation *alloc = allocate_blocks(block_len + 1);
+ u32 extent_block = 0;
+ u32 file_block = 0;
+ struct ext4_extent *extent;
+ u64 blocks;
+
+ if (alloc == NULL) {
+ error("Failed to allocate %d blocks\n", block_len + 1);
+ return NULL;
+ }
+
+ int allocation_len = block_allocation_num_regions(alloc);
+ if (allocation_len <= 3) {
+ reduce_allocation(alloc, 1);
+ } else {
+ reserve_oob_blocks(alloc, 1);
+ extent_block = get_oob_block(alloc, 0);
+ }
+
+ if (!extent_block) {
+ struct ext4_extent_header *hdr =
+ (struct ext4_extent_header *)&inode->i_block[0];
+ hdr->eh_magic = EXT4_EXT_MAGIC;
+ hdr->eh_entries = allocation_len;
+ hdr->eh_max = 3;
+ hdr->eh_generation = 0;
+ hdr->eh_depth = 0;
+
+ extent = (struct ext4_extent *)&inode->i_block[3];
+ } else {
+ struct ext4_extent_header *hdr =
+ (struct ext4_extent_header *)&inode->i_block[0];
+ hdr->eh_magic = EXT4_EXT_MAGIC;
+ hdr->eh_entries = 1;
+ hdr->eh_max = 3;
+ hdr->eh_generation = 0;
+ hdr->eh_depth = 1;
+
+ struct ext4_extent_idx *idx =
+ (struct ext4_extent_idx *)&inode->i_block[3];
+ idx->ei_block = 0;
+ idx->ei_leaf_lo = extent_block;
+ idx->ei_leaf_hi = 0;
+ idx->ei_unused = 0;
+
+ u8 *data = calloc(info.block_size, 1);
+ if (!data)
+ critical_error_errno("calloc");
+
+ queue_data_block(data, info.block_size, extent_block);
+
+ if (((int)(info.block_size - sizeof(struct ext4_extent_header) /
+ sizeof(struct ext4_extent))) < allocation_len) {
+ error("File size %llu is too big to fit in a single extent block\n",
+ len);
+ return NULL;
+ }
+
+ hdr = (struct ext4_extent_header *)data;
+ hdr->eh_magic = EXT4_EXT_MAGIC;
+ hdr->eh_entries = allocation_len;
+ hdr->eh_max = (info.block_size - sizeof(struct ext4_extent_header)) /
+ sizeof(struct ext4_extent);
+ hdr->eh_generation = 0;
+ hdr->eh_depth = 0;
+
+ extent = (struct ext4_extent *)(data +
+ sizeof(struct ext4_extent_header));
+ }
+
+ for (; !last_region(alloc); extent++, get_next_region(alloc)) {
+ u32 region_block;
+ u32 region_len;
+
+ get_region(alloc, ®ion_block, ®ion_len);
+ extent->ee_block = file_block;
+ extent->ee_len = region_len;
+ extent->ee_start_hi = 0;
+ extent->ee_start_lo = region_block;
+ file_block += region_len;
+ }
+
+ if (extent_block)
+ block_len += 1;
+
+ blocks = (u64)block_len * info.block_size / 512;
+
+ inode->i_flags |= EXT4_EXTENTS_FL;
+ inode->i_size_lo = len;
+ inode->i_size_high = len >> 32;
+ inode->i_blocks_lo = blocks;
+ inode->osd2.linux2.l_i_blocks_high = blocks >> 32;
+
+ rewind_alloc(alloc);
+
+ return alloc;
+}
+
+/* Allocates enough blocks to hold len bytes, with backing_len bytes in a data
+ buffer, and connects them to an inode. Returns a pointer to the data
+ buffer. */
+u8 *inode_allocate_data_extents(struct ext4_inode *inode, u64 len,
+ u64 backing_len)
+{
+ struct block_allocation *alloc;
+ u8 *data = NULL;
+
+ alloc = do_inode_allocate_extents(inode, len);
+ if (alloc == NULL) {
+ error("failed to allocate extents for %llu bytes", len);
+ return NULL;
+ }
+
+ if (backing_len) {
+ data = extent_create_backing(alloc, backing_len);
+ if (!data)
+ error("failed to create backing for %llu bytes", backing_len);
+ }
+
+ free_alloc(alloc);
+
+ return data;
+}
+
+/* Allocates enough blocks to hold len bytes, queues them to be written
+ from a file, and connects them to an inode. */
+void inode_allocate_file_extents(struct ext4_inode *inode, u64 len,
+ const char *filename)
+{
+ struct block_allocation *alloc;
+
+ alloc = do_inode_allocate_extents(inode, len);
+ if (alloc == NULL) {
+ error("failed to allocate extents for %llu bytes", len);
+ return;
+ }
+
+ extent_create_backing_file(alloc, len, filename);
+
+ free_alloc(alloc);
+}
+
+/* Allocates enough blocks to hold len bytes and connects them to an inode */
+void inode_allocate_extents(struct ext4_inode *inode, u64 len)
+{
+ struct block_allocation *alloc;
+
+ alloc = do_inode_allocate_extents(inode, len);
+ if (alloc == NULL) {
+ error("failed to allocate extents for %llu bytes", len);
+ return;
+ }
+
+ free_alloc(alloc);
+}
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