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https://git.proxmox.com/git/mirror_zfs.git
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d3c12383c9
This commit changes the provider compress and decompress API to take ABD pointers instead of buffer pointers for both data source and destination. It then updates all providers to match. This doesn't actually change the providers to do chunked compression, just changes the API to allow such an update in the future. Helper macros are added to easily adapt the ABD functions to their buffer-based implementations. Sponsored-by: Klara, Inc. Sponsored-by: Wasabi Technology, Inc. Signed-off-by: Rob Norris <rob.norris@klarasystems.com>
232 lines
7.1 KiB
C
232 lines
7.1 KiB
C
/*
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* BSD 3-Clause New License (https://spdx.org/licenses/BSD-3-Clause.html)
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* 1. Redistributions of source code must retain the above copyright notice,
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* this list of conditions and the following disclaimer.
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*
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* 2. Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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*
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* 3. Neither the name of the copyright holder nor the names of its
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* contributors may be used to endorse or promote products derived from this
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* software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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/*
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* Copyright (c) 2016-2018, Klara Inc.
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* Copyright (c) 2016-2018, Allan Jude
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* Copyright (c) 2018-2020, Sebastian Gottschall
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* Copyright (c) 2019-2020, Michael Niewöhner
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* Copyright (c) 2020, The FreeBSD Foundation [1]
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*
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* [1] Portions of this software were developed by Allan Jude
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* under sponsorship from the FreeBSD Foundation.
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*/
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#ifndef _ZFS_ZSTD_H
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#define _ZFS_ZSTD_H
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#ifdef __cplusplus
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extern "C" {
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#endif
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/*
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* ZSTD block header
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* NOTE: all fields in this header are in big endian order.
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*/
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typedef struct zfs_zstd_header {
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/* Compressed size of data */
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uint32_t c_len;
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/*
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* Version and compression level
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* We used to use a union to reference compression level
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* and version easily, but as it turns out, relying on the
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* ordering of bitfields is not remotely portable.
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* So now we have get/set functions in zfs_zstd.c for
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* manipulating this in just the right way forever.
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*/
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uint32_t raw_version_level;
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char data[];
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} zfs_zstdhdr_t;
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/*
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* Simple struct to pass the data from raw_version_level around.
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*/
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typedef struct zfs_zstd_meta {
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uint8_t level;
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uint32_t version;
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} zfs_zstdmeta_t;
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/*
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* kstat helper macros
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*/
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#define ZSTDSTAT(stat) (zstd_stats.stat.value.ui64)
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#define ZSTDSTAT_ZERO(stat) \
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atomic_store_64(&zstd_stats.stat.value.ui64, 0)
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#define ZSTDSTAT_ADD(stat, val) \
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atomic_add_64(&zstd_stats.stat.value.ui64, (val))
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#define ZSTDSTAT_SUB(stat, val) \
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atomic_sub_64(&zstd_stats.stat.value.ui64, (val))
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#define ZSTDSTAT_BUMP(stat) ZSTDSTAT_ADD(stat, 1)
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/* (de)init for user space / kernel emulation */
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int zstd_init(void);
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void zstd_fini(void);
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size_t zfs_zstd_compress(abd_t *src, abd_t *dst, size_t s_len,
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size_t d_len, int level);
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int zfs_zstd_get_level(void *s_start, size_t s_len, uint8_t *level);
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int zfs_zstd_decompress_level(abd_t *src, abd_t *dst, size_t s_len,
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size_t d_len, uint8_t *level);
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int zfs_zstd_decompress(abd_t *src, abd_t *dst, size_t s_len,
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size_t d_len, int n);
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void zfs_zstd_cache_reap_now(void);
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/*
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* So, the reason we have all these complicated set/get functions is that
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* originally, in the zstd "header" we wrote out to disk, we used a 32-bit
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* bitfield to store the "level" (8 bits) and "version" (24 bits).
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*
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* Unfortunately, bitfields make few promises about how they're arranged in
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* memory...
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*
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* By way of example, if we were using version 1.4.5 and level 3, it'd be
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* level = 0x03, version = 10405/0x0028A5, which gets broken into Vhigh = 0x00,
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* Vmid = 0x28, Vlow = 0xA5. We include these positions below to help follow
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* which data winds up where.
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*
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* As a consequence, we wound up with little endian platforms with a layout
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* like this in memory:
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*
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* 0 8 16 24 32
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* +-------+-------+-------+-------+
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* | Vlow | Vmid | Vhigh | level |
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* +-------+-------+-------+-------+
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* =A5 =28 =00 =03
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*
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* ...and then, after being run through BE_32(), serializing this out to
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* disk:
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*
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* 0 8 16 24 32
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* +-------+-------+-------+-------+
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* | level | Vhigh | Vmid | Vlow |
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* +-------+-------+-------+-------+
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* =03 =00 =28 =A5
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*
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* while on big-endian systems, since BE_32() is a noop there, both in
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* memory and on disk, we wind up with:
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*
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* 0 8 16 24 32
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* +-------+-------+-------+-------+
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* | Vhigh | Vmid | Vlow | level |
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* +-------+-------+-------+-------+
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* =00 =28 =A5 =03
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*
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* (Vhigh is always 0 until version exceeds 6.55.35. Vmid and Vlow are the
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* other two bytes of the "version" data.)
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*
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* So now we use the BF32_SET macros to get consistent behavior (the
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* ondisk LE encoding, since x86 currently rules the world) across
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* platforms, but the "get" behavior requires that we check each of the
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* bytes in the aforementioned former-bitfield for 0x00, and from there,
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* we can know which possible layout we're dealing with. (Only the two
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* that have been observed in the wild are illustrated above, but handlers
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* for all 4 positions of 0x00 are implemented.
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*/
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static inline void
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zfs_get_hdrmeta(const zfs_zstdhdr_t *blob, zfs_zstdmeta_t *res)
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{
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uint32_t raw = blob->raw_version_level;
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uint8_t findme = 0xff;
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int shift;
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for (shift = 0; shift < 4; shift++) {
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findme = BF32_GET(raw, 8*shift, 8);
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if (findme == 0)
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break;
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}
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switch (shift) {
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case 0:
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res->level = BF32_GET(raw, 24, 8);
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res->version = BSWAP_32(raw);
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res->version = BF32_GET(res->version, 8, 24);
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break;
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case 1:
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res->level = BF32_GET(raw, 0, 8);
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res->version = BSWAP_32(raw);
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res->version = BF32_GET(res->version, 0, 24);
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break;
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case 2:
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res->level = BF32_GET(raw, 24, 8);
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res->version = BF32_GET(raw, 0, 24);
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break;
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case 3:
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res->level = BF32_GET(raw, 0, 8);
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res->version = BF32_GET(raw, 8, 24);
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break;
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default:
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res->level = 0;
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res->version = 0;
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break;
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}
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}
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static inline uint8_t
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zfs_get_hdrlevel(const zfs_zstdhdr_t *blob)
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{
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uint8_t level = 0;
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zfs_zstdmeta_t res;
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zfs_get_hdrmeta(blob, &res);
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level = res.level;
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return (level);
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}
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static inline uint32_t
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zfs_get_hdrversion(const zfs_zstdhdr_t *blob)
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{
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uint32_t version = 0;
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zfs_zstdmeta_t res;
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zfs_get_hdrmeta(blob, &res);
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version = res.version;
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return (version);
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}
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static inline void
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zfs_set_hdrversion(zfs_zstdhdr_t *blob, uint32_t version)
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{
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/* cppcheck-suppress syntaxError */
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BF32_SET(blob->raw_version_level, 0, 24, version);
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}
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static inline void
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zfs_set_hdrlevel(zfs_zstdhdr_t *blob, uint8_t level)
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{
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/* cppcheck-suppress syntaxError */
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BF32_SET(blob->raw_version_level, 24, 8, level);
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}
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#ifdef __cplusplus
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}
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#endif
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#endif /* _ZFS_ZSTD_H */
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