| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <b552e551-6961-b95a-1af3-0c9114447528@linux.alibaba.com>
Date: Sun, 30 Jul 2023 22:06:14 +0800
From: Gao Xiang <hsiangkao@...ux.alibaba.com>
To: Chao Yu <chao@...nel.org>, linux-erofs@...ts.ozlabs.org
Cc: LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v4] erofs: DEFLATE compression support
On 2023/7/30 22:05, Gao Xiang wrote:
>
>
> On 2023/7/30 22:01, Chao Yu wrote:
>> On 2023/7/30 21:49, Gao Xiang wrote:
>>>
>>>
>>> On 2023/7/30 20:53, Chao Yu wrote:
>>>> On 2023/7/16 17:19, Gao Xiang wrote:
>>>>> Add DEFLATE compression as the 3rd supported algorithm.
>>>>>
>>>>> DEFLATE is a popular generic-purpose compression algorithm for quite
>>>>> long time (many advanced formats like gzip, zlib, zip, png are all
>>>>> based on that) as Apple documentation written "If you require
>>>>> interoperability with non-Apple devices, use COMPRESSION_ZLIB. [1]".
>>>>>
>>>>> Due to its popularity, there are several hardware on-market DEFLATE
>>>>> accelerators, such as (s390) DFLTCC, (Intel) IAA/QAT, (HiSilicon) ZIP
>>>>> accelerator, etc. In addition, there are also several high-performence
>>>>> IP cores and even open-source FPGA approches available for DEFLATE.
>>>>> Therefore, it's useful to support DEFLATE compression in order to find
>>>>> a way to utilize these accelerators for asynchronous I/Os and get
>>>>> benefits from these later.
>>>>>
>>>>> Besides, it's a good choice to trade off between compression ratios
>>>>> and performance compared to LZ4 and LZMA. The DEFLATE core format is
>>>>> simple as well as easy to understand, therefore the code size of its
>>>>> decompressor is small even for the bootloader use cases. The runtime
>>>>> memory consumption is quite limited too (e.g. 32K + ~7K for each zlib
>>>>> stream). As usual, EROFS ourperforms similar approaches too.
>>>>>
>>>>> Alternatively, DEFLATE could still be used for some specific files
>>>>> since EROFS supports multiple compression algorithms in one image.
>>>>>
>>>>> [1] https://developer.apple.com/documentation/compression/compression_algorithm
>>>>> ---
>>>>> changes since v3:
>>>>> - fix 'insz' mis-calculation, which leads to failure on 4k pclusters.
>>>>>
>>>>> fs/erofs/Kconfig | 15 ++
>>>>> fs/erofs/Makefile | 1 +
>>>>> fs/erofs/compress.h | 2 +
>>>>> fs/erofs/decompressor.c | 6 +
>>>>> fs/erofs/decompressor_deflate.c | 250 ++++++++++++++++++++++++++++++++
>>>>> fs/erofs/erofs_fs.h | 7 +
>>>>> fs/erofs/internal.h | 20 +++
>>>>> fs/erofs/super.c | 10 ++
>>>>> fs/erofs/zmap.c | 5 +-
>>>>> 9 files changed, 314 insertions(+), 2 deletions(-)
>>>>> create mode 100644 fs/erofs/decompressor_deflate.c
>>>>>
>>>>> diff --git a/fs/erofs/Kconfig b/fs/erofs/Kconfig
>>>>> index f259d92c9720..56a99ba8ce22 100644
>>>>> --- a/fs/erofs/Kconfig
>>>>> +++ b/fs/erofs/Kconfig
>>>>> @@ -99,6 +99,21 @@ config EROFS_FS_ZIP_LZMA
>>>>> If unsure, say N.
>>>>> +config EROFS_FS_ZIP_DEFLATE
>>>>> + bool "EROFS DEFLATE compressed data support"
>>>>> + depends on EROFS_FS_ZIP
>>>>> + select ZLIB_INFLATE
>>>>> + help
>>>>> + Saying Y here includes support for reading EROFS file systems
>>>>> + containing DEFLATE compressed data. It gives better compression
>>>>> + ratios than the default LZ4 format, while it costs more CPU
>>>>> + overhead.
>>>>> +
>>>>> + DEFLATE support is an experimental feature for now and so most
>>>>> + file systems will be readable without selecting this option.
>>>>> +
>>>>> + If unsure, say N.
>>>>> +
>>>>> config EROFS_FS_ONDEMAND
>>>>> bool "EROFS fscache-based on-demand read support"
>>>>> depends on CACHEFILES_ONDEMAND && (EROFS_FS=m && FSCACHE || EROFS_FS=y && FSCACHE=y)
>>>>> diff --git a/fs/erofs/Makefile b/fs/erofs/Makefile
>>>>> index a3a98fc3e481..994d0b9deddf 100644
>>>>> --- a/fs/erofs/Makefile
>>>>> +++ b/fs/erofs/Makefile
>>>>> @@ -5,4 +5,5 @@ erofs-objs := super.o inode.o data.o namei.o dir.o utils.o sysfs.o
>>>>> erofs-$(CONFIG_EROFS_FS_XATTR) += xattr.o
>>>>> erofs-$(CONFIG_EROFS_FS_ZIP) += decompressor.o zmap.o zdata.o pcpubuf.o
>>>>> erofs-$(CONFIG_EROFS_FS_ZIP_LZMA) += decompressor_lzma.o
>>>>> +erofs-$(CONFIG_EROFS_FS_ZIP_DEFLATE) += decompressor_deflate.o
>>>>> erofs-$(CONFIG_EROFS_FS_ONDEMAND) += fscache.o
>>>>> diff --git a/fs/erofs/compress.h b/fs/erofs/compress.h
>>>>> index b1b846504027..349c3316ae6b 100644
>>>>> --- a/fs/erofs/compress.h
>>>>> +++ b/fs/erofs/compress.h
>>>>> @@ -94,4 +94,6 @@ extern const struct z_erofs_decompressor erofs_decompressors[];
>>>>> /* prototypes for specific algorithms */
>>>>> int z_erofs_lzma_decompress(struct z_erofs_decompress_req *rq,
>>>>> struct page **pagepool);
>>>>> +int z_erofs_deflate_decompress(struct z_erofs_decompress_req *rq,
>>>>> + struct page **pagepool);
>>>>> #endif
>>>>> diff --git a/fs/erofs/decompressor.c b/fs/erofs/decompressor.c
>>>>> index cfad1eac7fd9..332ec5f74002 100644
>>>>> --- a/fs/erofs/decompressor.c
>>>>> +++ b/fs/erofs/decompressor.c
>>>>> @@ -379,4 +379,10 @@ const struct z_erofs_decompressor erofs_decompressors[] = {
>>>>> .name = "lzma"
>>>>> },
>>>>> #endif
>>>>> +#ifdef CONFIG_EROFS_FS_ZIP_DEFLATE
>>>>> + [Z_EROFS_COMPRESSION_DEFLATE] = {
>>>>> + .decompress = z_erofs_deflate_decompress,
>>>>> + .name = "deflate"
>>>>> + },
>>>>> +#endif
>>>>> };
>>>>> diff --git a/fs/erofs/decompressor_deflate.c b/fs/erofs/decompressor_deflate.c
>>>>> new file mode 100644
>>>>> index 000000000000..c34e29b15465
>>>>> --- /dev/null
>>>>> +++ b/fs/erofs/decompressor_deflate.c
>>>>> @@ -0,0 +1,250 @@
>>>>> +// SPDX-License-Identifier: GPL-2.0-or-later
>>>>> +#include <linux/module.h>
>>>>> +#include <linux/zlib.h>
>>>>> +#include "compress.h"
>>>>> +
>>>>> +struct z_erofs_deflate {
>>>>> + struct z_erofs_deflate *next;
>>>>> + struct z_stream_s z;
>>>>> + u8 bounce[PAGE_SIZE];
>>>>> +};
>>>>> +
>>>>> +static DEFINE_SPINLOCK(z_erofs_deflate_lock);
>>>>> +static unsigned int z_erofs_deflate_nstrms, z_erofs_deflate_avail_strms;
>>>>> +static struct z_erofs_deflate *z_erofs_deflate_head;
>>>>> +static DECLARE_WAIT_QUEUE_HEAD(z_erofs_deflate_wq);
>>>>> +
>>>>> +module_param_named(deflate_streams, z_erofs_deflate_nstrms, uint, 0444);
>>>>> +
>>>>> +void z_erofs_deflate_exit(void)
>>>>> +{
>>>>> + /* there should be no running fs instance */
>>>>> + while (z_erofs_deflate_avail_strms) {
>>>>> + struct z_erofs_deflate *strm;
>>>>> +
>>>>> + spin_lock(&z_erofs_deflate_lock);
>>>>> + strm = z_erofs_deflate_head;
>>>>> + if (!strm) {
>>>>> + spin_unlock(&z_erofs_deflate_lock);
>>>>> + DBG_BUGON(1);
>>>>> + return;
>>>>> + }
>>>>> + z_erofs_deflate_head = NULL;
>>>>> + spin_unlock(&z_erofs_deflate_lock);
>>>>> +
>>>>> + while (strm) {
>>>>> + struct z_erofs_deflate *n = strm->next;
>>>>> +
>>>>> + vfree(strm->z.workspace);
>>>>> + kfree(strm);
>>>>> + --z_erofs_deflate_avail_strms;
>>>>> + strm = n;
>>>>> + }
>>>>> + }
>>>>> +}
>>>>> +
>>>>> +int __init z_erofs_deflate_init(void)
>>>>> +{
>>>>> + /* by default, use # of possible CPUs instead */
>>>>> + if (!z_erofs_deflate_nstrms)
>>>>> + z_erofs_deflate_nstrms = num_possible_cpus();
>>>>> +
>>>>> + for (; z_erofs_deflate_avail_strms < z_erofs_deflate_nstrms;
>>>>> + ++z_erofs_deflate_avail_strms) {
>>>>> + struct z_erofs_deflate *strm;
>>>>> +
>>>>> + strm = kzalloc(sizeof(*strm), GFP_KERNEL);
>>>>> + if (!strm)
>>>>> + goto out_failed;
>>>>> +
>>>>> + /* XXX: in-kernel zlib cannot shrink windowbits currently */
>>>>> + strm->z.workspace = vmalloc(zlib_inflate_workspacesize());
>>>>> + if (!strm->z.workspace)
>>>>
>>>> kfree(strm)?
>>>
>>> z_erofs_deflate_exit() below will handle this.
>>
>> strm is not in z_erofs_deflate_head list yet?
>>
>> Thanks
>>
>>>
>>> Thanks,
>>> Gao Xiang
>>>
>>>>
>>>> Thanks,
>>>>
>>>>> + goto out_failed;
>>>>> +
>>>>> + spin_lock(&z_erofs_deflate_lock);
>>>>> + strm->next = z_erofs_deflate_head;
>>>>> + z_erofs_deflate_head = strm;
>
> z_erofs_deflate_head will be added in each turn here.
Or you are right, thanks for pointing out, I will
make a version soon.
Thanks,
Gao Xiang
Powered by blists - more mailing lists