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![Liu Bo](/assets/img/avatar_default.png)
Argument 'root' is no more used in btrfs_csum_data(). Signed-off-by: Liu Bo <bo.li.liu@oracle.com> Signed-off-by: Josef Bacik <jbacik@fusionio.com>
1047 lines
27 KiB
C
1047 lines
27 KiB
C
/*
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* Copyright (C) 2008 Oracle. All rights reserved.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public
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* License v2 as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public
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* License along with this program; if not, write to the
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* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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* Boston, MA 021110-1307, USA.
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*/
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#include <linux/kernel.h>
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#include <linux/bio.h>
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#include <linux/buffer_head.h>
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#include <linux/file.h>
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#include <linux/fs.h>
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#include <linux/pagemap.h>
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#include <linux/highmem.h>
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#include <linux/time.h>
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#include <linux/init.h>
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#include <linux/string.h>
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#include <linux/backing-dev.h>
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#include <linux/mpage.h>
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#include <linux/swap.h>
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#include <linux/writeback.h>
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#include <linux/bit_spinlock.h>
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#include <linux/slab.h>
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#include "compat.h"
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#include "ctree.h"
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#include "disk-io.h"
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#include "transaction.h"
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#include "btrfs_inode.h"
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#include "volumes.h"
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#include "ordered-data.h"
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#include "compression.h"
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#include "extent_io.h"
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#include "extent_map.h"
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struct compressed_bio {
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/* number of bios pending for this compressed extent */
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atomic_t pending_bios;
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/* the pages with the compressed data on them */
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struct page **compressed_pages;
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/* inode that owns this data */
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struct inode *inode;
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/* starting offset in the inode for our pages */
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u64 start;
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/* number of bytes in the inode we're working on */
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unsigned long len;
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/* number of bytes on disk */
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unsigned long compressed_len;
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/* the compression algorithm for this bio */
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int compress_type;
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/* number of compressed pages in the array */
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unsigned long nr_pages;
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/* IO errors */
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int errors;
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int mirror_num;
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/* for reads, this is the bio we are copying the data into */
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struct bio *orig_bio;
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/*
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* the start of a variable length array of checksums only
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* used by reads
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*/
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u32 sums;
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};
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static inline int compressed_bio_size(struct btrfs_root *root,
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unsigned long disk_size)
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{
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u16 csum_size = btrfs_super_csum_size(root->fs_info->super_copy);
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return sizeof(struct compressed_bio) +
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((disk_size + root->sectorsize - 1) / root->sectorsize) *
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csum_size;
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}
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static struct bio *compressed_bio_alloc(struct block_device *bdev,
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u64 first_byte, gfp_t gfp_flags)
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{
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int nr_vecs;
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nr_vecs = bio_get_nr_vecs(bdev);
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return btrfs_bio_alloc(bdev, first_byte >> 9, nr_vecs, gfp_flags);
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}
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static int check_compressed_csum(struct inode *inode,
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struct compressed_bio *cb,
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u64 disk_start)
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{
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int ret;
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struct page *page;
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unsigned long i;
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char *kaddr;
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u32 csum;
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u32 *cb_sum = &cb->sums;
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if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM)
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return 0;
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for (i = 0; i < cb->nr_pages; i++) {
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page = cb->compressed_pages[i];
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csum = ~(u32)0;
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kaddr = kmap_atomic(page);
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csum = btrfs_csum_data(kaddr, csum, PAGE_CACHE_SIZE);
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btrfs_csum_final(csum, (char *)&csum);
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kunmap_atomic(kaddr);
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if (csum != *cb_sum) {
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printk(KERN_INFO "btrfs csum failed ino %llu "
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"extent %llu csum %u "
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"wanted %u mirror %d\n",
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(unsigned long long)btrfs_ino(inode),
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(unsigned long long)disk_start,
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csum, *cb_sum, cb->mirror_num);
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ret = -EIO;
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goto fail;
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}
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cb_sum++;
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}
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ret = 0;
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fail:
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return ret;
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}
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/* when we finish reading compressed pages from the disk, we
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* decompress them and then run the bio end_io routines on the
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* decompressed pages (in the inode address space).
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*
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* This allows the checksumming and other IO error handling routines
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* to work normally
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*
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* The compressed pages are freed here, and it must be run
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* in process context
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*/
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static void end_compressed_bio_read(struct bio *bio, int err)
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{
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struct compressed_bio *cb = bio->bi_private;
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struct inode *inode;
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struct page *page;
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unsigned long index;
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int ret;
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if (err)
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cb->errors = 1;
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/* if there are more bios still pending for this compressed
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* extent, just exit
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*/
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if (!atomic_dec_and_test(&cb->pending_bios))
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goto out;
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inode = cb->inode;
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ret = check_compressed_csum(inode, cb, (u64)bio->bi_sector << 9);
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if (ret)
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goto csum_failed;
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/* ok, we're the last bio for this extent, lets start
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* the decompression.
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*/
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ret = btrfs_decompress_biovec(cb->compress_type,
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cb->compressed_pages,
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cb->start,
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cb->orig_bio->bi_io_vec,
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cb->orig_bio->bi_vcnt,
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cb->compressed_len);
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csum_failed:
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if (ret)
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cb->errors = 1;
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/* release the compressed pages */
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index = 0;
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for (index = 0; index < cb->nr_pages; index++) {
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page = cb->compressed_pages[index];
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page->mapping = NULL;
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page_cache_release(page);
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}
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/* do io completion on the original bio */
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if (cb->errors) {
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bio_io_error(cb->orig_bio);
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} else {
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int bio_index = 0;
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struct bio_vec *bvec = cb->orig_bio->bi_io_vec;
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/*
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* we have verified the checksum already, set page
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* checked so the end_io handlers know about it
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*/
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while (bio_index < cb->orig_bio->bi_vcnt) {
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SetPageChecked(bvec->bv_page);
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bvec++;
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bio_index++;
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}
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bio_endio(cb->orig_bio, 0);
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}
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/* finally free the cb struct */
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kfree(cb->compressed_pages);
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kfree(cb);
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out:
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bio_put(bio);
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}
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/*
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* Clear the writeback bits on all of the file
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* pages for a compressed write
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*/
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static noinline void end_compressed_writeback(struct inode *inode, u64 start,
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unsigned long ram_size)
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{
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unsigned long index = start >> PAGE_CACHE_SHIFT;
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unsigned long end_index = (start + ram_size - 1) >> PAGE_CACHE_SHIFT;
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struct page *pages[16];
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unsigned long nr_pages = end_index - index + 1;
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int i;
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int ret;
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while (nr_pages > 0) {
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ret = find_get_pages_contig(inode->i_mapping, index,
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min_t(unsigned long,
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nr_pages, ARRAY_SIZE(pages)), pages);
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if (ret == 0) {
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nr_pages -= 1;
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index += 1;
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continue;
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}
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for (i = 0; i < ret; i++) {
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end_page_writeback(pages[i]);
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page_cache_release(pages[i]);
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}
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nr_pages -= ret;
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index += ret;
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}
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/* the inode may be gone now */
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}
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/*
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* do the cleanup once all the compressed pages hit the disk.
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* This will clear writeback on the file pages and free the compressed
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* pages.
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*
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* This also calls the writeback end hooks for the file pages so that
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* metadata and checksums can be updated in the file.
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*/
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static void end_compressed_bio_write(struct bio *bio, int err)
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{
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struct extent_io_tree *tree;
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struct compressed_bio *cb = bio->bi_private;
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struct inode *inode;
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struct page *page;
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unsigned long index;
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if (err)
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cb->errors = 1;
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/* if there are more bios still pending for this compressed
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* extent, just exit
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*/
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if (!atomic_dec_and_test(&cb->pending_bios))
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goto out;
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/* ok, we're the last bio for this extent, step one is to
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* call back into the FS and do all the end_io operations
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*/
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inode = cb->inode;
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tree = &BTRFS_I(inode)->io_tree;
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cb->compressed_pages[0]->mapping = cb->inode->i_mapping;
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tree->ops->writepage_end_io_hook(cb->compressed_pages[0],
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cb->start,
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cb->start + cb->len - 1,
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NULL, 1);
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cb->compressed_pages[0]->mapping = NULL;
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end_compressed_writeback(inode, cb->start, cb->len);
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/* note, our inode could be gone now */
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/*
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* release the compressed pages, these came from alloc_page and
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* are not attached to the inode at all
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*/
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index = 0;
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for (index = 0; index < cb->nr_pages; index++) {
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page = cb->compressed_pages[index];
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page->mapping = NULL;
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page_cache_release(page);
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}
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/* finally free the cb struct */
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kfree(cb->compressed_pages);
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kfree(cb);
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out:
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bio_put(bio);
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}
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/*
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* worker function to build and submit bios for previously compressed pages.
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* The corresponding pages in the inode should be marked for writeback
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* and the compressed pages should have a reference on them for dropping
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* when the IO is complete.
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*
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* This also checksums the file bytes and gets things ready for
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* the end io hooks.
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*/
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int btrfs_submit_compressed_write(struct inode *inode, u64 start,
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unsigned long len, u64 disk_start,
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unsigned long compressed_len,
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struct page **compressed_pages,
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unsigned long nr_pages)
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{
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struct bio *bio = NULL;
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struct btrfs_root *root = BTRFS_I(inode)->root;
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struct compressed_bio *cb;
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unsigned long bytes_left;
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struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
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int pg_index = 0;
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struct page *page;
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u64 first_byte = disk_start;
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struct block_device *bdev;
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int ret;
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int skip_sum = BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM;
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WARN_ON(start & ((u64)PAGE_CACHE_SIZE - 1));
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cb = kmalloc(compressed_bio_size(root, compressed_len), GFP_NOFS);
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if (!cb)
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return -ENOMEM;
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atomic_set(&cb->pending_bios, 0);
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cb->errors = 0;
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cb->inode = inode;
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cb->start = start;
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cb->len = len;
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cb->mirror_num = 0;
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cb->compressed_pages = compressed_pages;
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cb->compressed_len = compressed_len;
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cb->orig_bio = NULL;
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cb->nr_pages = nr_pages;
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bdev = BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev;
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bio = compressed_bio_alloc(bdev, first_byte, GFP_NOFS);
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if(!bio) {
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kfree(cb);
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return -ENOMEM;
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}
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bio->bi_private = cb;
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bio->bi_end_io = end_compressed_bio_write;
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atomic_inc(&cb->pending_bios);
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|
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/* create and submit bios for the compressed pages */
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bytes_left = compressed_len;
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for (pg_index = 0; pg_index < cb->nr_pages; pg_index++) {
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page = compressed_pages[pg_index];
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page->mapping = inode->i_mapping;
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if (bio->bi_size)
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ret = io_tree->ops->merge_bio_hook(WRITE, page, 0,
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PAGE_CACHE_SIZE,
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bio, 0);
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else
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ret = 0;
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page->mapping = NULL;
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if (ret || bio_add_page(bio, page, PAGE_CACHE_SIZE, 0) <
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PAGE_CACHE_SIZE) {
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bio_get(bio);
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/*
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* inc the count before we submit the bio so
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* we know the end IO handler won't happen before
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* we inc the count. Otherwise, the cb might get
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* freed before we're done setting it up
|
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*/
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atomic_inc(&cb->pending_bios);
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ret = btrfs_bio_wq_end_io(root->fs_info, bio, 0);
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BUG_ON(ret); /* -ENOMEM */
|
|
|
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if (!skip_sum) {
|
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ret = btrfs_csum_one_bio(root, inode, bio,
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start, 1);
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BUG_ON(ret); /* -ENOMEM */
|
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}
|
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|
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ret = btrfs_map_bio(root, WRITE, bio, 0, 1);
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BUG_ON(ret); /* -ENOMEM */
|
|
|
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bio_put(bio);
|
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|
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bio = compressed_bio_alloc(bdev, first_byte, GFP_NOFS);
|
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BUG_ON(!bio);
|
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bio->bi_private = cb;
|
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bio->bi_end_io = end_compressed_bio_write;
|
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bio_add_page(bio, page, PAGE_CACHE_SIZE, 0);
|
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}
|
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if (bytes_left < PAGE_CACHE_SIZE) {
|
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printk("bytes left %lu compress len %lu nr %lu\n",
|
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bytes_left, cb->compressed_len, cb->nr_pages);
|
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}
|
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bytes_left -= PAGE_CACHE_SIZE;
|
|
first_byte += PAGE_CACHE_SIZE;
|
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cond_resched();
|
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}
|
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bio_get(bio);
|
|
|
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ret = btrfs_bio_wq_end_io(root->fs_info, bio, 0);
|
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BUG_ON(ret); /* -ENOMEM */
|
|
|
|
if (!skip_sum) {
|
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ret = btrfs_csum_one_bio(root, inode, bio, start, 1);
|
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BUG_ON(ret); /* -ENOMEM */
|
|
}
|
|
|
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ret = btrfs_map_bio(root, WRITE, bio, 0, 1);
|
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BUG_ON(ret); /* -ENOMEM */
|
|
|
|
bio_put(bio);
|
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return 0;
|
|
}
|
|
|
|
static noinline int add_ra_bio_pages(struct inode *inode,
|
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u64 compressed_end,
|
|
struct compressed_bio *cb)
|
|
{
|
|
unsigned long end_index;
|
|
unsigned long pg_index;
|
|
u64 last_offset;
|
|
u64 isize = i_size_read(inode);
|
|
int ret;
|
|
struct page *page;
|
|
unsigned long nr_pages = 0;
|
|
struct extent_map *em;
|
|
struct address_space *mapping = inode->i_mapping;
|
|
struct extent_map_tree *em_tree;
|
|
struct extent_io_tree *tree;
|
|
u64 end;
|
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int misses = 0;
|
|
|
|
page = cb->orig_bio->bi_io_vec[cb->orig_bio->bi_vcnt - 1].bv_page;
|
|
last_offset = (page_offset(page) + PAGE_CACHE_SIZE);
|
|
em_tree = &BTRFS_I(inode)->extent_tree;
|
|
tree = &BTRFS_I(inode)->io_tree;
|
|
|
|
if (isize == 0)
|
|
return 0;
|
|
|
|
end_index = (i_size_read(inode) - 1) >> PAGE_CACHE_SHIFT;
|
|
|
|
while (last_offset < compressed_end) {
|
|
pg_index = last_offset >> PAGE_CACHE_SHIFT;
|
|
|
|
if (pg_index > end_index)
|
|
break;
|
|
|
|
rcu_read_lock();
|
|
page = radix_tree_lookup(&mapping->page_tree, pg_index);
|
|
rcu_read_unlock();
|
|
if (page) {
|
|
misses++;
|
|
if (misses > 4)
|
|
break;
|
|
goto next;
|
|
}
|
|
|
|
page = __page_cache_alloc(mapping_gfp_mask(mapping) &
|
|
~__GFP_FS);
|
|
if (!page)
|
|
break;
|
|
|
|
if (add_to_page_cache_lru(page, mapping, pg_index,
|
|
GFP_NOFS)) {
|
|
page_cache_release(page);
|
|
goto next;
|
|
}
|
|
|
|
end = last_offset + PAGE_CACHE_SIZE - 1;
|
|
/*
|
|
* at this point, we have a locked page in the page cache
|
|
* for these bytes in the file. But, we have to make
|
|
* sure they map to this compressed extent on disk.
|
|
*/
|
|
set_page_extent_mapped(page);
|
|
lock_extent(tree, last_offset, end);
|
|
read_lock(&em_tree->lock);
|
|
em = lookup_extent_mapping(em_tree, last_offset,
|
|
PAGE_CACHE_SIZE);
|
|
read_unlock(&em_tree->lock);
|
|
|
|
if (!em || last_offset < em->start ||
|
|
(last_offset + PAGE_CACHE_SIZE > extent_map_end(em)) ||
|
|
(em->block_start >> 9) != cb->orig_bio->bi_sector) {
|
|
free_extent_map(em);
|
|
unlock_extent(tree, last_offset, end);
|
|
unlock_page(page);
|
|
page_cache_release(page);
|
|
break;
|
|
}
|
|
free_extent_map(em);
|
|
|
|
if (page->index == end_index) {
|
|
char *userpage;
|
|
size_t zero_offset = isize & (PAGE_CACHE_SIZE - 1);
|
|
|
|
if (zero_offset) {
|
|
int zeros;
|
|
zeros = PAGE_CACHE_SIZE - zero_offset;
|
|
userpage = kmap_atomic(page);
|
|
memset(userpage + zero_offset, 0, zeros);
|
|
flush_dcache_page(page);
|
|
kunmap_atomic(userpage);
|
|
}
|
|
}
|
|
|
|
ret = bio_add_page(cb->orig_bio, page,
|
|
PAGE_CACHE_SIZE, 0);
|
|
|
|
if (ret == PAGE_CACHE_SIZE) {
|
|
nr_pages++;
|
|
page_cache_release(page);
|
|
} else {
|
|
unlock_extent(tree, last_offset, end);
|
|
unlock_page(page);
|
|
page_cache_release(page);
|
|
break;
|
|
}
|
|
next:
|
|
last_offset += PAGE_CACHE_SIZE;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* for a compressed read, the bio we get passed has all the inode pages
|
|
* in it. We don't actually do IO on those pages but allocate new ones
|
|
* to hold the compressed pages on disk.
|
|
*
|
|
* bio->bi_sector points to the compressed extent on disk
|
|
* bio->bi_io_vec points to all of the inode pages
|
|
* bio->bi_vcnt is a count of pages
|
|
*
|
|
* After the compressed pages are read, we copy the bytes into the
|
|
* bio we were passed and then call the bio end_io calls
|
|
*/
|
|
int btrfs_submit_compressed_read(struct inode *inode, struct bio *bio,
|
|
int mirror_num, unsigned long bio_flags)
|
|
{
|
|
struct extent_io_tree *tree;
|
|
struct extent_map_tree *em_tree;
|
|
struct compressed_bio *cb;
|
|
struct btrfs_root *root = BTRFS_I(inode)->root;
|
|
unsigned long uncompressed_len = bio->bi_vcnt * PAGE_CACHE_SIZE;
|
|
unsigned long compressed_len;
|
|
unsigned long nr_pages;
|
|
unsigned long pg_index;
|
|
struct page *page;
|
|
struct block_device *bdev;
|
|
struct bio *comp_bio;
|
|
u64 cur_disk_byte = (u64)bio->bi_sector << 9;
|
|
u64 em_len;
|
|
u64 em_start;
|
|
struct extent_map *em;
|
|
int ret = -ENOMEM;
|
|
int faili = 0;
|
|
u32 *sums;
|
|
|
|
tree = &BTRFS_I(inode)->io_tree;
|
|
em_tree = &BTRFS_I(inode)->extent_tree;
|
|
|
|
/* we need the actual starting offset of this extent in the file */
|
|
read_lock(&em_tree->lock);
|
|
em = lookup_extent_mapping(em_tree,
|
|
page_offset(bio->bi_io_vec->bv_page),
|
|
PAGE_CACHE_SIZE);
|
|
read_unlock(&em_tree->lock);
|
|
if (!em)
|
|
return -EIO;
|
|
|
|
compressed_len = em->block_len;
|
|
cb = kmalloc(compressed_bio_size(root, compressed_len), GFP_NOFS);
|
|
if (!cb)
|
|
goto out;
|
|
|
|
atomic_set(&cb->pending_bios, 0);
|
|
cb->errors = 0;
|
|
cb->inode = inode;
|
|
cb->mirror_num = mirror_num;
|
|
sums = &cb->sums;
|
|
|
|
cb->start = em->orig_start;
|
|
em_len = em->len;
|
|
em_start = em->start;
|
|
|
|
free_extent_map(em);
|
|
em = NULL;
|
|
|
|
cb->len = uncompressed_len;
|
|
cb->compressed_len = compressed_len;
|
|
cb->compress_type = extent_compress_type(bio_flags);
|
|
cb->orig_bio = bio;
|
|
|
|
nr_pages = (compressed_len + PAGE_CACHE_SIZE - 1) /
|
|
PAGE_CACHE_SIZE;
|
|
cb->compressed_pages = kzalloc(sizeof(struct page *) * nr_pages,
|
|
GFP_NOFS);
|
|
if (!cb->compressed_pages)
|
|
goto fail1;
|
|
|
|
bdev = BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev;
|
|
|
|
for (pg_index = 0; pg_index < nr_pages; pg_index++) {
|
|
cb->compressed_pages[pg_index] = alloc_page(GFP_NOFS |
|
|
__GFP_HIGHMEM);
|
|
if (!cb->compressed_pages[pg_index]) {
|
|
faili = pg_index - 1;
|
|
ret = -ENOMEM;
|
|
goto fail2;
|
|
}
|
|
}
|
|
faili = nr_pages - 1;
|
|
cb->nr_pages = nr_pages;
|
|
|
|
add_ra_bio_pages(inode, em_start + em_len, cb);
|
|
|
|
/* include any pages we added in add_ra-bio_pages */
|
|
uncompressed_len = bio->bi_vcnt * PAGE_CACHE_SIZE;
|
|
cb->len = uncompressed_len;
|
|
|
|
comp_bio = compressed_bio_alloc(bdev, cur_disk_byte, GFP_NOFS);
|
|
if (!comp_bio)
|
|
goto fail2;
|
|
comp_bio->bi_private = cb;
|
|
comp_bio->bi_end_io = end_compressed_bio_read;
|
|
atomic_inc(&cb->pending_bios);
|
|
|
|
for (pg_index = 0; pg_index < nr_pages; pg_index++) {
|
|
page = cb->compressed_pages[pg_index];
|
|
page->mapping = inode->i_mapping;
|
|
page->index = em_start >> PAGE_CACHE_SHIFT;
|
|
|
|
if (comp_bio->bi_size)
|
|
ret = tree->ops->merge_bio_hook(READ, page, 0,
|
|
PAGE_CACHE_SIZE,
|
|
comp_bio, 0);
|
|
else
|
|
ret = 0;
|
|
|
|
page->mapping = NULL;
|
|
if (ret || bio_add_page(comp_bio, page, PAGE_CACHE_SIZE, 0) <
|
|
PAGE_CACHE_SIZE) {
|
|
bio_get(comp_bio);
|
|
|
|
ret = btrfs_bio_wq_end_io(root->fs_info, comp_bio, 0);
|
|
BUG_ON(ret); /* -ENOMEM */
|
|
|
|
/*
|
|
* inc the count before we submit the bio so
|
|
* we know the end IO handler won't happen before
|
|
* we inc the count. Otherwise, the cb might get
|
|
* freed before we're done setting it up
|
|
*/
|
|
atomic_inc(&cb->pending_bios);
|
|
|
|
if (!(BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM)) {
|
|
ret = btrfs_lookup_bio_sums(root, inode,
|
|
comp_bio, sums);
|
|
BUG_ON(ret); /* -ENOMEM */
|
|
}
|
|
sums += (comp_bio->bi_size + root->sectorsize - 1) /
|
|
root->sectorsize;
|
|
|
|
ret = btrfs_map_bio(root, READ, comp_bio,
|
|
mirror_num, 0);
|
|
if (ret)
|
|
bio_endio(comp_bio, ret);
|
|
|
|
bio_put(comp_bio);
|
|
|
|
comp_bio = compressed_bio_alloc(bdev, cur_disk_byte,
|
|
GFP_NOFS);
|
|
BUG_ON(!comp_bio);
|
|
comp_bio->bi_private = cb;
|
|
comp_bio->bi_end_io = end_compressed_bio_read;
|
|
|
|
bio_add_page(comp_bio, page, PAGE_CACHE_SIZE, 0);
|
|
}
|
|
cur_disk_byte += PAGE_CACHE_SIZE;
|
|
}
|
|
bio_get(comp_bio);
|
|
|
|
ret = btrfs_bio_wq_end_io(root->fs_info, comp_bio, 0);
|
|
BUG_ON(ret); /* -ENOMEM */
|
|
|
|
if (!(BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM)) {
|
|
ret = btrfs_lookup_bio_sums(root, inode, comp_bio, sums);
|
|
BUG_ON(ret); /* -ENOMEM */
|
|
}
|
|
|
|
ret = btrfs_map_bio(root, READ, comp_bio, mirror_num, 0);
|
|
if (ret)
|
|
bio_endio(comp_bio, ret);
|
|
|
|
bio_put(comp_bio);
|
|
return 0;
|
|
|
|
fail2:
|
|
while (faili >= 0) {
|
|
__free_page(cb->compressed_pages[faili]);
|
|
faili--;
|
|
}
|
|
|
|
kfree(cb->compressed_pages);
|
|
fail1:
|
|
kfree(cb);
|
|
out:
|
|
free_extent_map(em);
|
|
return ret;
|
|
}
|
|
|
|
static struct list_head comp_idle_workspace[BTRFS_COMPRESS_TYPES];
|
|
static spinlock_t comp_workspace_lock[BTRFS_COMPRESS_TYPES];
|
|
static int comp_num_workspace[BTRFS_COMPRESS_TYPES];
|
|
static atomic_t comp_alloc_workspace[BTRFS_COMPRESS_TYPES];
|
|
static wait_queue_head_t comp_workspace_wait[BTRFS_COMPRESS_TYPES];
|
|
|
|
struct btrfs_compress_op *btrfs_compress_op[] = {
|
|
&btrfs_zlib_compress,
|
|
&btrfs_lzo_compress,
|
|
};
|
|
|
|
void __init btrfs_init_compress(void)
|
|
{
|
|
int i;
|
|
|
|
for (i = 0; i < BTRFS_COMPRESS_TYPES; i++) {
|
|
INIT_LIST_HEAD(&comp_idle_workspace[i]);
|
|
spin_lock_init(&comp_workspace_lock[i]);
|
|
atomic_set(&comp_alloc_workspace[i], 0);
|
|
init_waitqueue_head(&comp_workspace_wait[i]);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* this finds an available workspace or allocates a new one
|
|
* ERR_PTR is returned if things go bad.
|
|
*/
|
|
static struct list_head *find_workspace(int type)
|
|
{
|
|
struct list_head *workspace;
|
|
int cpus = num_online_cpus();
|
|
int idx = type - 1;
|
|
|
|
struct list_head *idle_workspace = &comp_idle_workspace[idx];
|
|
spinlock_t *workspace_lock = &comp_workspace_lock[idx];
|
|
atomic_t *alloc_workspace = &comp_alloc_workspace[idx];
|
|
wait_queue_head_t *workspace_wait = &comp_workspace_wait[idx];
|
|
int *num_workspace = &comp_num_workspace[idx];
|
|
again:
|
|
spin_lock(workspace_lock);
|
|
if (!list_empty(idle_workspace)) {
|
|
workspace = idle_workspace->next;
|
|
list_del(workspace);
|
|
(*num_workspace)--;
|
|
spin_unlock(workspace_lock);
|
|
return workspace;
|
|
|
|
}
|
|
if (atomic_read(alloc_workspace) > cpus) {
|
|
DEFINE_WAIT(wait);
|
|
|
|
spin_unlock(workspace_lock);
|
|
prepare_to_wait(workspace_wait, &wait, TASK_UNINTERRUPTIBLE);
|
|
if (atomic_read(alloc_workspace) > cpus && !*num_workspace)
|
|
schedule();
|
|
finish_wait(workspace_wait, &wait);
|
|
goto again;
|
|
}
|
|
atomic_inc(alloc_workspace);
|
|
spin_unlock(workspace_lock);
|
|
|
|
workspace = btrfs_compress_op[idx]->alloc_workspace();
|
|
if (IS_ERR(workspace)) {
|
|
atomic_dec(alloc_workspace);
|
|
wake_up(workspace_wait);
|
|
}
|
|
return workspace;
|
|
}
|
|
|
|
/*
|
|
* put a workspace struct back on the list or free it if we have enough
|
|
* idle ones sitting around
|
|
*/
|
|
static void free_workspace(int type, struct list_head *workspace)
|
|
{
|
|
int idx = type - 1;
|
|
struct list_head *idle_workspace = &comp_idle_workspace[idx];
|
|
spinlock_t *workspace_lock = &comp_workspace_lock[idx];
|
|
atomic_t *alloc_workspace = &comp_alloc_workspace[idx];
|
|
wait_queue_head_t *workspace_wait = &comp_workspace_wait[idx];
|
|
int *num_workspace = &comp_num_workspace[idx];
|
|
|
|
spin_lock(workspace_lock);
|
|
if (*num_workspace < num_online_cpus()) {
|
|
list_add_tail(workspace, idle_workspace);
|
|
(*num_workspace)++;
|
|
spin_unlock(workspace_lock);
|
|
goto wake;
|
|
}
|
|
spin_unlock(workspace_lock);
|
|
|
|
btrfs_compress_op[idx]->free_workspace(workspace);
|
|
atomic_dec(alloc_workspace);
|
|
wake:
|
|
smp_mb();
|
|
if (waitqueue_active(workspace_wait))
|
|
wake_up(workspace_wait);
|
|
}
|
|
|
|
/*
|
|
* cleanup function for module exit
|
|
*/
|
|
static void free_workspaces(void)
|
|
{
|
|
struct list_head *workspace;
|
|
int i;
|
|
|
|
for (i = 0; i < BTRFS_COMPRESS_TYPES; i++) {
|
|
while (!list_empty(&comp_idle_workspace[i])) {
|
|
workspace = comp_idle_workspace[i].next;
|
|
list_del(workspace);
|
|
btrfs_compress_op[i]->free_workspace(workspace);
|
|
atomic_dec(&comp_alloc_workspace[i]);
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
* given an address space and start/len, compress the bytes.
|
|
*
|
|
* pages are allocated to hold the compressed result and stored
|
|
* in 'pages'
|
|
*
|
|
* out_pages is used to return the number of pages allocated. There
|
|
* may be pages allocated even if we return an error
|
|
*
|
|
* total_in is used to return the number of bytes actually read. It
|
|
* may be smaller then len if we had to exit early because we
|
|
* ran out of room in the pages array or because we cross the
|
|
* max_out threshold.
|
|
*
|
|
* total_out is used to return the total number of compressed bytes
|
|
*
|
|
* max_out tells us the max number of bytes that we're allowed to
|
|
* stuff into pages
|
|
*/
|
|
int btrfs_compress_pages(int type, struct address_space *mapping,
|
|
u64 start, unsigned long len,
|
|
struct page **pages,
|
|
unsigned long nr_dest_pages,
|
|
unsigned long *out_pages,
|
|
unsigned long *total_in,
|
|
unsigned long *total_out,
|
|
unsigned long max_out)
|
|
{
|
|
struct list_head *workspace;
|
|
int ret;
|
|
|
|
workspace = find_workspace(type);
|
|
if (IS_ERR(workspace))
|
|
return -1;
|
|
|
|
ret = btrfs_compress_op[type-1]->compress_pages(workspace, mapping,
|
|
start, len, pages,
|
|
nr_dest_pages, out_pages,
|
|
total_in, total_out,
|
|
max_out);
|
|
free_workspace(type, workspace);
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* pages_in is an array of pages with compressed data.
|
|
*
|
|
* disk_start is the starting logical offset of this array in the file
|
|
*
|
|
* bvec is a bio_vec of pages from the file that we want to decompress into
|
|
*
|
|
* vcnt is the count of pages in the biovec
|
|
*
|
|
* srclen is the number of bytes in pages_in
|
|
*
|
|
* The basic idea is that we have a bio that was created by readpages.
|
|
* The pages in the bio are for the uncompressed data, and they may not
|
|
* be contiguous. They all correspond to the range of bytes covered by
|
|
* the compressed extent.
|
|
*/
|
|
int btrfs_decompress_biovec(int type, struct page **pages_in, u64 disk_start,
|
|
struct bio_vec *bvec, int vcnt, size_t srclen)
|
|
{
|
|
struct list_head *workspace;
|
|
int ret;
|
|
|
|
workspace = find_workspace(type);
|
|
if (IS_ERR(workspace))
|
|
return -ENOMEM;
|
|
|
|
ret = btrfs_compress_op[type-1]->decompress_biovec(workspace, pages_in,
|
|
disk_start,
|
|
bvec, vcnt, srclen);
|
|
free_workspace(type, workspace);
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* a less complex decompression routine. Our compressed data fits in a
|
|
* single page, and we want to read a single page out of it.
|
|
* start_byte tells us the offset into the compressed data we're interested in
|
|
*/
|
|
int btrfs_decompress(int type, unsigned char *data_in, struct page *dest_page,
|
|
unsigned long start_byte, size_t srclen, size_t destlen)
|
|
{
|
|
struct list_head *workspace;
|
|
int ret;
|
|
|
|
workspace = find_workspace(type);
|
|
if (IS_ERR(workspace))
|
|
return -ENOMEM;
|
|
|
|
ret = btrfs_compress_op[type-1]->decompress(workspace, data_in,
|
|
dest_page, start_byte,
|
|
srclen, destlen);
|
|
|
|
free_workspace(type, workspace);
|
|
return ret;
|
|
}
|
|
|
|
void btrfs_exit_compress(void)
|
|
{
|
|
free_workspaces();
|
|
}
|
|
|
|
/*
|
|
* Copy uncompressed data from working buffer to pages.
|
|
*
|
|
* buf_start is the byte offset we're of the start of our workspace buffer.
|
|
*
|
|
* total_out is the last byte of the buffer
|
|
*/
|
|
int btrfs_decompress_buf2page(char *buf, unsigned long buf_start,
|
|
unsigned long total_out, u64 disk_start,
|
|
struct bio_vec *bvec, int vcnt,
|
|
unsigned long *pg_index,
|
|
unsigned long *pg_offset)
|
|
{
|
|
unsigned long buf_offset;
|
|
unsigned long current_buf_start;
|
|
unsigned long start_byte;
|
|
unsigned long working_bytes = total_out - buf_start;
|
|
unsigned long bytes;
|
|
char *kaddr;
|
|
struct page *page_out = bvec[*pg_index].bv_page;
|
|
|
|
/*
|
|
* start byte is the first byte of the page we're currently
|
|
* copying into relative to the start of the compressed data.
|
|
*/
|
|
start_byte = page_offset(page_out) - disk_start;
|
|
|
|
/* we haven't yet hit data corresponding to this page */
|
|
if (total_out <= start_byte)
|
|
return 1;
|
|
|
|
/*
|
|
* the start of the data we care about is offset into
|
|
* the middle of our working buffer
|
|
*/
|
|
if (total_out > start_byte && buf_start < start_byte) {
|
|
buf_offset = start_byte - buf_start;
|
|
working_bytes -= buf_offset;
|
|
} else {
|
|
buf_offset = 0;
|
|
}
|
|
current_buf_start = buf_start;
|
|
|
|
/* copy bytes from the working buffer into the pages */
|
|
while (working_bytes > 0) {
|
|
bytes = min(PAGE_CACHE_SIZE - *pg_offset,
|
|
PAGE_CACHE_SIZE - buf_offset);
|
|
bytes = min(bytes, working_bytes);
|
|
kaddr = kmap_atomic(page_out);
|
|
memcpy(kaddr + *pg_offset, buf + buf_offset, bytes);
|
|
kunmap_atomic(kaddr);
|
|
flush_dcache_page(page_out);
|
|
|
|
*pg_offset += bytes;
|
|
buf_offset += bytes;
|
|
working_bytes -= bytes;
|
|
current_buf_start += bytes;
|
|
|
|
/* check if we need to pick another page */
|
|
if (*pg_offset == PAGE_CACHE_SIZE) {
|
|
(*pg_index)++;
|
|
if (*pg_index >= vcnt)
|
|
return 0;
|
|
|
|
page_out = bvec[*pg_index].bv_page;
|
|
*pg_offset = 0;
|
|
start_byte = page_offset(page_out) - disk_start;
|
|
|
|
/*
|
|
* make sure our new page is covered by this
|
|
* working buffer
|
|
*/
|
|
if (total_out <= start_byte)
|
|
return 1;
|
|
|
|
/*
|
|
* the next page in the biovec might not be adjacent
|
|
* to the last page, but it might still be found
|
|
* inside this working buffer. bump our offset pointer
|
|
*/
|
|
if (total_out > start_byte &&
|
|
current_buf_start < start_byte) {
|
|
buf_offset = start_byte - buf_start;
|
|
working_bytes = total_out - start_byte;
|
|
current_buf_start = buf_start + buf_offset;
|
|
}
|
|
}
|
|
}
|
|
|
|
return 1;
|
|
}
|