mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-23 17:30:02 +00:00
![Xiaoming Ni](/assets/img/avatar_default.png)
Patch series 'squashfs: Add the mount parameter "threads="'. Currently, Squashfs supports multiple decompressor parallel modes. However, this mode can be configured only during kernel building and does not support flexible selection during runtime. In the current patch set, the mount parameter "threads=" is added to allow users to select the parallel decompressor mode and configure the number of decompressors when mounting a file system. "threads=<single|multi|percpu|1|2|3|...>" The upper limit is num_online_cpus() * 2. This patch (of 2): Squashfs supports three decompression concurrency modes: Single-thread mode: concurrent reads are blocked and the memory overhead is small. Multi-thread mode/percpu mode: reduces concurrent read blocking but increases memory overhead. The corresponding schema must be fixed at compile time. During mounting, the concurrent decompression mode cannot be adjusted based on file read blocking. The mount parameter theads=<single|multi|percpu> is added to select the concurrent decompression mode of a single SquashFS file system image. Link: https://lkml.kernel.org/r/20221019030930.130456-1-nixiaoming@huawei.com Link: https://lkml.kernel.org/r/20221019030930.130456-2-nixiaoming@huawei.com Signed-off-by: Xiaoming Ni <nixiaoming@huawei.com> Reviewed-by: Phillip Lougher <phillip@squashfs.org.uk> Cc: Jianguo Chen <chenjianguo3@huawei.com> Cc: Jubin Zhong <zhongjubin@huawei.com> Cc: Zhang Yi <yi.zhang@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
236 lines
5.9 KiB
C
236 lines
5.9 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
|
|
/*
|
|
* Squashfs - a compressed read only filesystem for Linux
|
|
*
|
|
* Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008
|
|
* Phillip Lougher <phillip@squashfs.org.uk>
|
|
*
|
|
* block.c
|
|
*/
|
|
|
|
/*
|
|
* This file implements the low-level routines to read and decompress
|
|
* datablocks and metadata blocks.
|
|
*/
|
|
|
|
#include <linux/blkdev.h>
|
|
#include <linux/fs.h>
|
|
#include <linux/vfs.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/string.h>
|
|
#include <linux/buffer_head.h>
|
|
#include <linux/bio.h>
|
|
|
|
#include "squashfs_fs.h"
|
|
#include "squashfs_fs_sb.h"
|
|
#include "squashfs.h"
|
|
#include "decompressor.h"
|
|
#include "page_actor.h"
|
|
|
|
/*
|
|
* Returns the amount of bytes copied to the page actor.
|
|
*/
|
|
static int copy_bio_to_actor(struct bio *bio,
|
|
struct squashfs_page_actor *actor,
|
|
int offset, int req_length)
|
|
{
|
|
void *actor_addr;
|
|
struct bvec_iter_all iter_all = {};
|
|
struct bio_vec *bvec = bvec_init_iter_all(&iter_all);
|
|
int copied_bytes = 0;
|
|
int actor_offset = 0;
|
|
|
|
squashfs_actor_nobuff(actor);
|
|
actor_addr = squashfs_first_page(actor);
|
|
|
|
if (WARN_ON_ONCE(!bio_next_segment(bio, &iter_all)))
|
|
return 0;
|
|
|
|
while (copied_bytes < req_length) {
|
|
int bytes_to_copy = min_t(int, bvec->bv_len - offset,
|
|
PAGE_SIZE - actor_offset);
|
|
|
|
bytes_to_copy = min_t(int, bytes_to_copy,
|
|
req_length - copied_bytes);
|
|
if (!IS_ERR(actor_addr))
|
|
memcpy(actor_addr + actor_offset, bvec_virt(bvec) +
|
|
offset, bytes_to_copy);
|
|
|
|
actor_offset += bytes_to_copy;
|
|
copied_bytes += bytes_to_copy;
|
|
offset += bytes_to_copy;
|
|
|
|
if (actor_offset >= PAGE_SIZE) {
|
|
actor_addr = squashfs_next_page(actor);
|
|
if (!actor_addr)
|
|
break;
|
|
actor_offset = 0;
|
|
}
|
|
if (offset >= bvec->bv_len) {
|
|
if (!bio_next_segment(bio, &iter_all))
|
|
break;
|
|
offset = 0;
|
|
}
|
|
}
|
|
squashfs_finish_page(actor);
|
|
return copied_bytes;
|
|
}
|
|
|
|
static int squashfs_bio_read(struct super_block *sb, u64 index, int length,
|
|
struct bio **biop, int *block_offset)
|
|
{
|
|
struct squashfs_sb_info *msblk = sb->s_fs_info;
|
|
const u64 read_start = round_down(index, msblk->devblksize);
|
|
const sector_t block = read_start >> msblk->devblksize_log2;
|
|
const u64 read_end = round_up(index + length, msblk->devblksize);
|
|
const sector_t block_end = read_end >> msblk->devblksize_log2;
|
|
int offset = read_start - round_down(index, PAGE_SIZE);
|
|
int total_len = (block_end - block) << msblk->devblksize_log2;
|
|
const int page_count = DIV_ROUND_UP(total_len + offset, PAGE_SIZE);
|
|
int error, i;
|
|
struct bio *bio;
|
|
|
|
bio = bio_kmalloc(page_count, GFP_NOIO);
|
|
if (!bio)
|
|
return -ENOMEM;
|
|
bio_init(bio, sb->s_bdev, bio->bi_inline_vecs, page_count, REQ_OP_READ);
|
|
bio->bi_iter.bi_sector = block * (msblk->devblksize >> SECTOR_SHIFT);
|
|
|
|
for (i = 0; i < page_count; ++i) {
|
|
unsigned int len =
|
|
min_t(unsigned int, PAGE_SIZE - offset, total_len);
|
|
struct page *page = alloc_page(GFP_NOIO);
|
|
|
|
if (!page) {
|
|
error = -ENOMEM;
|
|
goto out_free_bio;
|
|
}
|
|
if (!bio_add_page(bio, page, len, offset)) {
|
|
error = -EIO;
|
|
goto out_free_bio;
|
|
}
|
|
offset = 0;
|
|
total_len -= len;
|
|
}
|
|
|
|
error = submit_bio_wait(bio);
|
|
if (error)
|
|
goto out_free_bio;
|
|
|
|
*biop = bio;
|
|
*block_offset = index & ((1 << msblk->devblksize_log2) - 1);
|
|
return 0;
|
|
|
|
out_free_bio:
|
|
bio_free_pages(bio);
|
|
bio_uninit(bio);
|
|
kfree(bio);
|
|
return error;
|
|
}
|
|
|
|
/*
|
|
* Read and decompress a metadata block or datablock. Length is non-zero
|
|
* if a datablock is being read (the size is stored elsewhere in the
|
|
* filesystem), otherwise the length is obtained from the first two bytes of
|
|
* the metadata block. A bit in the length field indicates if the block
|
|
* is stored uncompressed in the filesystem (usually because compression
|
|
* generated a larger block - this does occasionally happen with compression
|
|
* algorithms).
|
|
*/
|
|
int squashfs_read_data(struct super_block *sb, u64 index, int length,
|
|
u64 *next_index, struct squashfs_page_actor *output)
|
|
{
|
|
struct squashfs_sb_info *msblk = sb->s_fs_info;
|
|
struct bio *bio = NULL;
|
|
int compressed;
|
|
int res;
|
|
int offset;
|
|
|
|
if (length) {
|
|
/*
|
|
* Datablock.
|
|
*/
|
|
compressed = SQUASHFS_COMPRESSED_BLOCK(length);
|
|
length = SQUASHFS_COMPRESSED_SIZE_BLOCK(length);
|
|
TRACE("Block @ 0x%llx, %scompressed size %d, src size %d\n",
|
|
index, compressed ? "" : "un", length, output->length);
|
|
} else {
|
|
/*
|
|
* Metadata block.
|
|
*/
|
|
const u8 *data;
|
|
struct bvec_iter_all iter_all = {};
|
|
struct bio_vec *bvec = bvec_init_iter_all(&iter_all);
|
|
|
|
if (index + 2 > msblk->bytes_used) {
|
|
res = -EIO;
|
|
goto out;
|
|
}
|
|
res = squashfs_bio_read(sb, index, 2, &bio, &offset);
|
|
if (res)
|
|
goto out;
|
|
|
|
if (WARN_ON_ONCE(!bio_next_segment(bio, &iter_all))) {
|
|
res = -EIO;
|
|
goto out_free_bio;
|
|
}
|
|
/* Extract the length of the metadata block */
|
|
data = bvec_virt(bvec);
|
|
length = data[offset];
|
|
if (offset < bvec->bv_len - 1) {
|
|
length |= data[offset + 1] << 8;
|
|
} else {
|
|
if (WARN_ON_ONCE(!bio_next_segment(bio, &iter_all))) {
|
|
res = -EIO;
|
|
goto out_free_bio;
|
|
}
|
|
data = bvec_virt(bvec);
|
|
length |= data[0] << 8;
|
|
}
|
|
bio_free_pages(bio);
|
|
bio_uninit(bio);
|
|
kfree(bio);
|
|
|
|
compressed = SQUASHFS_COMPRESSED(length);
|
|
length = SQUASHFS_COMPRESSED_SIZE(length);
|
|
index += 2;
|
|
|
|
TRACE("Block @ 0x%llx, %scompressed size %d\n", index - 2,
|
|
compressed ? "" : "un", length);
|
|
}
|
|
if (length < 0 || length > output->length ||
|
|
(index + length) > msblk->bytes_used) {
|
|
res = -EIO;
|
|
goto out;
|
|
}
|
|
|
|
if (next_index)
|
|
*next_index = index + length;
|
|
|
|
res = squashfs_bio_read(sb, index, length, &bio, &offset);
|
|
if (res)
|
|
goto out;
|
|
|
|
if (compressed) {
|
|
if (!msblk->stream) {
|
|
res = -EIO;
|
|
goto out_free_bio;
|
|
}
|
|
res = msblk->thread_ops->decompress(msblk, bio, offset, length, output);
|
|
} else {
|
|
res = copy_bio_to_actor(bio, output, offset, length);
|
|
}
|
|
|
|
out_free_bio:
|
|
bio_free_pages(bio);
|
|
bio_uninit(bio);
|
|
kfree(bio);
|
|
out:
|
|
if (res < 0) {
|
|
ERROR("Failed to read block 0x%llx: %d\n", index, res);
|
|
if (msblk->panic_on_errors)
|
|
panic("squashfs read failed");
|
|
}
|
|
|
|
return res;
|
|
}
|