/*
* Copyright (C) 2008 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/kernel.h>
#include <linux/bio.h>
#include <linux/buffer_head.h>
#include <linux/file.h>
#include <linux/fs.h>
#include <linux/pagemap.h>
#include <linux/highmem.h>
#include <linux/time.h>
#include <linux/init.h>
#include <linux/string.h>
#include <linux/backing-dev.h>
#include <linux/mpage.h>
#include <linux/swap.h>
#include <linux/writeback.h>
#include <linux/bit_spinlock.h>
#include <linux/slab.h>
#include "ctree.h"
#include "disk-io.h"
#include "transaction.h"
#include "btrfs_inode.h"
#include "volumes.h"
#include "ordered-data.h"
#include "compression.h"
#include "extent_io.h"
#include "extent_map.h"
struct compressed_bio {
/* number of bios pending for this compressed extent */
atomic_t pending_bios;
/* the pages with the compressed data on them */
struct page **compressed_pages;
/* inode that owns this data */
struct inode *inode;
/* starting offset in the inode for our pages */
u64 start;
/* number of bytes in the inode we're working on */
unsigned long len;
/* number of bytes on disk */
unsigned long compressed_len;
/* the compression algorithm for this bio */
int compress_type;
/* number of compressed pages in the array */
unsigned long nr_pages;
/* IO errors */
int errors;
int mirror_num;
/* for reads, this is the bio we are copying the data into */
struct bio *orig_bio;
/*
* the start of a variable length array of checksums only
* used by reads
*/
u32 sums;
};
static int btrfs_decompress_biovec(int type, struct page **pages_in,
u64 disk_start, struct bio_vec *bvec,
int vcnt, size_t srclen);
static inline int compressed_bio_size(struct btrfs_root *root,
unsigned long disk_size)
{
u16 csum_size = btrfs_super_csum_size(root->fs_info->super_copy);
return sizeof(struct compressed_bio) +
(DIV_ROUND_UP(disk_size, root->sectorsize)) * csum_size;
}
static struct bio *compressed_bio_alloc(struct block_device *bdev,
u64 first_byte, gfp_t gfp_flags)
{
return btrfs_bio_alloc(bdev, first_byte >> 9, BIO_MAX_PAGES, gfp_flags);
}
static int check_compressed_csum(struct inode *inode,
struct compressed_bio *cb,
u64 disk_start)
{
int ret;
struct page *page;
unsigned long i;
char *kaddr;
u32 csum;
u32 *cb_sum = &cb->sums;
if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM)
return 0;
for (i = 0; i < cb->nr_pages; i++) {
page = cb->compressed_pages[i];
csum = ~(u32)0;
kaddr = kmap_atomic(page);
csum = btrfs_csum_data(kaddr, csum, PAGE_CACHE_SIZE);
btrfs_csum_final(csum, (char *)&csum);
kunmap_atomic(kaddr);
if (csum != *cb_sum) {
btrfs_info(BTRFS_I(inode)->root->fs_info,
"csum failed ino %llu extent %llu csum %u wanted %u mirror %d",
btrfs_ino(inode), disk_start, csum, *cb_sum,
cb->mirror_num);
ret = -EIO;
goto fail;
}
cb_sum++;
}
ret = 0;
fail:
return ret;
}
/* when we finish reading compressed pages from the disk, we
* decompress them and then run the bio end_io routines on the
* decompressed pages (in the inode address space).
*
* This allows the checksumming and other IO error handling routines
* to work normally
*
* The compressed pages are freed here, and it must be run
* in process context
*/
static void end_compressed_bio_read(struct bio *bio)
{
struct compressed_bio *cb = bio->bi_private;