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https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
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707 lines
18 KiB
C
707 lines
18 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/pagevec.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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/* 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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struct bio *bio;
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int nr_vecs;
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nr_vecs = bio_get_nr_vecs(bdev);
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bio = bio_alloc(gfp_flags, nr_vecs);
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if (bio == NULL && (current->flags & PF_MEMALLOC)) {
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while (!bio && (nr_vecs /= 2))
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bio = bio_alloc(gfp_flags, nr_vecs);
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}
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if (bio) {
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bio->bi_size = 0;
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bio->bi_bdev = bdev;
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bio->bi_sector = first_byte >> 9;
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}
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return bio;
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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 btrfs_root *root = BTRFS_I(inode)->root;
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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, KM_USER0);
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csum = btrfs_csum_data(root, kaddr, csum, PAGE_CACHE_SIZE);
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btrfs_csum_final(csum, (char *)&csum);
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kunmap_atomic(kaddr, KM_USER0);
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if (csum != *cb_sum) {
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printk(KERN_INFO "btrfs csum failed ino %lu "
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"extent %llu csum %u "
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"wanted %u mirror %d\n", inode->i_ino,
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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 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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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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tree = &BTRFS_I(inode)->io_tree;
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ret = btrfs_zlib_decompress_biovec(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 int 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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return 0;
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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 page_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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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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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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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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/* create and submit bios for the compressed pages */
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bytes_left = compressed_len;
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for (page_index = 0; page_index < cb->nr_pages; page_index++) {
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page = compressed_pages[page_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(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);
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ret = btrfs_csum_one_bio(root, inode, bio, start, 1);
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BUG_ON(ret);
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ret = btrfs_map_bio(root, WRITE, bio, 0, 1);
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BUG_ON(ret);
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bio_put(bio);
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bio = compressed_bio_alloc(bdev, first_byte, GFP_NOFS);
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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;
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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);
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ret = btrfs_csum_one_bio(root, inode, bio, start, 1);
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BUG_ON(ret);
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ret = btrfs_map_bio(root, WRITE, bio, 0, 1);
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BUG_ON(ret);
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bio_put(bio);
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return 0;
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}
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static noinline int add_ra_bio_pages(struct inode *inode,
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u64 compressed_end,
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struct compressed_bio *cb)
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{
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unsigned long end_index;
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unsigned long page_index;
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u64 last_offset;
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u64 isize = i_size_read(inode);
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int ret;
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struct page *page;
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unsigned long nr_pages = 0;
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struct extent_map *em;
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struct address_space *mapping = inode->i_mapping;
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struct pagevec pvec;
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struct extent_map_tree *em_tree;
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struct extent_io_tree *tree;
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u64 end;
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int misses = 0;
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page = cb->orig_bio->bi_io_vec[cb->orig_bio->bi_vcnt - 1].bv_page;
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last_offset = (page_offset(page) + PAGE_CACHE_SIZE);
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em_tree = &BTRFS_I(inode)->extent_tree;
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tree = &BTRFS_I(inode)->io_tree;
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if (isize == 0)
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return 0;
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end_index = (i_size_read(inode) - 1) >> PAGE_CACHE_SHIFT;
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pagevec_init(&pvec, 0);
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while (last_offset < compressed_end) {
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page_index = last_offset >> PAGE_CACHE_SHIFT;
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if (page_index > end_index)
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break;
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rcu_read_lock();
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page = radix_tree_lookup(&mapping->page_tree, page_index);
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rcu_read_unlock();
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if (page) {
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misses++;
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if (misses > 4)
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break;
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goto next;
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}
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page = alloc_page(mapping_gfp_mask(mapping) | GFP_NOFS);
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if (!page)
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break;
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page->index = page_index;
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/*
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* what we want to do here is call add_to_page_cache_lru,
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* but that isn't exported, so we reproduce it here
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*/
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if (add_to_page_cache(page, mapping,
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page->index, GFP_NOFS)) {
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page_cache_release(page);
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goto next;
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}
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/* open coding of lru_cache_add, also not exported */
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page_cache_get(page);
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if (!pagevec_add(&pvec, page))
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__pagevec_lru_add_file(&pvec);
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end = last_offset + PAGE_CACHE_SIZE - 1;
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/*
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* at this point, we have a locked page in the page cache
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* for these bytes in the file. But, we have to make
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* sure they map to this compressed extent on disk.
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*/
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set_page_extent_mapped(page);
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lock_extent(tree, last_offset, end, GFP_NOFS);
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read_lock(&em_tree->lock);
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em = lookup_extent_mapping(em_tree, last_offset,
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PAGE_CACHE_SIZE);
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read_unlock(&em_tree->lock);
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if (!em || last_offset < em->start ||
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(last_offset + PAGE_CACHE_SIZE > extent_map_end(em)) ||
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(em->block_start >> 9) != cb->orig_bio->bi_sector) {
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free_extent_map(em);
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unlock_extent(tree, last_offset, end, GFP_NOFS);
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unlock_page(page);
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page_cache_release(page);
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break;
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}
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free_extent_map(em);
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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, KM_USER0);
|
|
memset(userpage + zero_offset, 0, zeros);
|
|
flush_dcache_page(page);
|
|
kunmap_atomic(userpage, KM_USER0);
|
|
}
|
|
}
|
|
|
|
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, GFP_NOFS);
|
|
unlock_page(page);
|
|
page_cache_release(page);
|
|
break;
|
|
}
|
|
next:
|
|
last_offset += PAGE_CACHE_SIZE;
|
|
}
|
|
if (pagevec_count(&pvec))
|
|
__pagevec_lru_add_file(&pvec);
|
|
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 page_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;
|
|
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);
|
|
|
|
compressed_len = em->block_len;
|
|
cb = kmalloc(compressed_bio_size(root, compressed_len), GFP_NOFS);
|
|
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->orig_bio = bio;
|
|
|
|
nr_pages = (compressed_len + PAGE_CACHE_SIZE - 1) /
|
|
PAGE_CACHE_SIZE;
|
|
cb->compressed_pages = kmalloc(sizeof(struct page *) * nr_pages,
|
|
GFP_NOFS);
|
|
bdev = BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev;
|
|
|
|
for (page_index = 0; page_index < nr_pages; page_index++) {
|
|
cb->compressed_pages[page_index] = alloc_page(GFP_NOFS |
|
|
__GFP_HIGHMEM);
|
|
}
|
|
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);
|
|
comp_bio->bi_private = cb;
|
|
comp_bio->bi_end_io = end_compressed_bio_read;
|
|
atomic_inc(&cb->pending_bios);
|
|
|
|
for (page_index = 0; page_index < nr_pages; page_index++) {
|
|
page = cb->compressed_pages[page_index];
|
|
page->mapping = inode->i_mapping;
|
|
page->index = em_start >> PAGE_CACHE_SHIFT;
|
|
|
|
if (comp_bio->bi_size)
|
|
ret = tree->ops->merge_bio_hook(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);
|
|
|
|
/*
|
|
* 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)) {
|
|
btrfs_lookup_bio_sums(root, inode, comp_bio,
|
|
sums);
|
|
}
|
|
sums += (comp_bio->bi_size + root->sectorsize - 1) /
|
|
root->sectorsize;
|
|
|
|
ret = btrfs_map_bio(root, READ, comp_bio,
|
|
mirror_num, 0);
|
|
BUG_ON(ret);
|
|
|
|
bio_put(comp_bio);
|
|
|
|
comp_bio = compressed_bio_alloc(bdev, cur_disk_byte,
|
|
GFP_NOFS);
|
|
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);
|
|
|
|
if (!(BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM))
|
|
btrfs_lookup_bio_sums(root, inode, comp_bio, sums);
|
|
|
|
ret = btrfs_map_bio(root, READ, comp_bio, mirror_num, 0);
|
|
BUG_ON(ret);
|
|
|
|
bio_put(comp_bio);
|
|
return 0;
|
|
}
|