linux/fs/bcachefs/compress.c
Kent Overstreet 6ddedca218 bcachefs: Guard against unknown compression options
Since compression options now include compression level, proper
validation is a bit more involved.

This adds bch2_compression_opt_valid(), and plumbs it around
appropriately.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-31 12:18:37 -04:00

721 lines
17 KiB
C

// SPDX-License-Identifier: GPL-2.0
#include "bcachefs.h"
#include "checksum.h"
#include "compress.h"
#include "extents.h"
#include "super-io.h"
#include <linux/lz4.h>
#include <linux/zlib.h>
#include <linux/zstd.h>
/* Bounce buffer: */
struct bbuf {
void *b;
enum {
BB_NONE,
BB_VMAP,
BB_KMALLOC,
BB_MEMPOOL,
} type;
int rw;
};
static struct bbuf __bounce_alloc(struct bch_fs *c, unsigned size, int rw)
{
void *b;
BUG_ON(size > c->opts.encoded_extent_max);
b = kmalloc(size, GFP_NOFS|__GFP_NOWARN);
if (b)
return (struct bbuf) { .b = b, .type = BB_KMALLOC, .rw = rw };
b = mempool_alloc(&c->compression_bounce[rw], GFP_NOFS);
if (b)
return (struct bbuf) { .b = b, .type = BB_MEMPOOL, .rw = rw };
BUG();
}
static bool bio_phys_contig(struct bio *bio, struct bvec_iter start)
{
struct bio_vec bv;
struct bvec_iter iter;
void *expected_start = NULL;
__bio_for_each_bvec(bv, bio, iter, start) {
if (expected_start &&
expected_start != page_address(bv.bv_page) + bv.bv_offset)
return false;
expected_start = page_address(bv.bv_page) +
bv.bv_offset + bv.bv_len;
}
return true;
}
static struct bbuf __bio_map_or_bounce(struct bch_fs *c, struct bio *bio,
struct bvec_iter start, int rw)
{
struct bbuf ret;
struct bio_vec bv;
struct bvec_iter iter;
unsigned nr_pages = 0;
struct page *stack_pages[16];
struct page **pages = NULL;
void *data;
BUG_ON(start.bi_size > c->opts.encoded_extent_max);
if (!PageHighMem(bio_iter_page(bio, start)) &&
bio_phys_contig(bio, start))
return (struct bbuf) {
.b = page_address(bio_iter_page(bio, start)) +
bio_iter_offset(bio, start),
.type = BB_NONE, .rw = rw
};
/* check if we can map the pages contiguously: */
__bio_for_each_segment(bv, bio, iter, start) {
if (iter.bi_size != start.bi_size &&
bv.bv_offset)
goto bounce;
if (bv.bv_len < iter.bi_size &&
bv.bv_offset + bv.bv_len < PAGE_SIZE)
goto bounce;
nr_pages++;
}
BUG_ON(DIV_ROUND_UP(start.bi_size, PAGE_SIZE) > nr_pages);
pages = nr_pages > ARRAY_SIZE(stack_pages)
? kmalloc_array(nr_pages, sizeof(struct page *), GFP_NOFS)
: stack_pages;
if (!pages)
goto bounce;
nr_pages = 0;
__bio_for_each_segment(bv, bio, iter, start)
pages[nr_pages++] = bv.bv_page;
data = vmap(pages, nr_pages, VM_MAP, PAGE_KERNEL);
if (pages != stack_pages)
kfree(pages);
if (data)
return (struct bbuf) {
.b = data + bio_iter_offset(bio, start),
.type = BB_VMAP, .rw = rw
};
bounce:
ret = __bounce_alloc(c, start.bi_size, rw);
if (rw == READ)
memcpy_from_bio(ret.b, bio, start);
return ret;
}
static struct bbuf bio_map_or_bounce(struct bch_fs *c, struct bio *bio, int rw)
{
return __bio_map_or_bounce(c, bio, bio->bi_iter, rw);
}
static void bio_unmap_or_unbounce(struct bch_fs *c, struct bbuf buf)
{
switch (buf.type) {
case BB_NONE:
break;
case BB_VMAP:
vunmap((void *) ((unsigned long) buf.b & PAGE_MASK));
break;
case BB_KMALLOC:
kfree(buf.b);
break;
case BB_MEMPOOL:
mempool_free(buf.b, &c->compression_bounce[buf.rw]);
break;
}
}
static inline void zlib_set_workspace(z_stream *strm, void *workspace)
{
#ifdef __KERNEL__
strm->workspace = workspace;
#endif
}
static int __bio_uncompress(struct bch_fs *c, struct bio *src,
void *dst_data, struct bch_extent_crc_unpacked crc)
{
struct bbuf src_data = { NULL };
size_t src_len = src->bi_iter.bi_size;
size_t dst_len = crc.uncompressed_size << 9;
void *workspace;
int ret;
src_data = bio_map_or_bounce(c, src, READ);
switch (crc.compression_type) {
case BCH_COMPRESSION_TYPE_lz4_old:
case BCH_COMPRESSION_TYPE_lz4:
ret = LZ4_decompress_safe_partial(src_data.b, dst_data,
src_len, dst_len, dst_len);
if (ret != dst_len)
goto err;
break;
case BCH_COMPRESSION_TYPE_gzip: {
z_stream strm = {
.next_in = src_data.b,
.avail_in = src_len,
.next_out = dst_data,
.avail_out = dst_len,
};
workspace = mempool_alloc(&c->decompress_workspace, GFP_NOFS);
zlib_set_workspace(&strm, workspace);
zlib_inflateInit2(&strm, -MAX_WBITS);
ret = zlib_inflate(&strm, Z_FINISH);
mempool_free(workspace, &c->decompress_workspace);
if (ret != Z_STREAM_END)
goto err;
break;
}
case BCH_COMPRESSION_TYPE_zstd: {
ZSTD_DCtx *ctx;
size_t real_src_len = le32_to_cpup(src_data.b);
if (real_src_len > src_len - 4)
goto err;
workspace = mempool_alloc(&c->decompress_workspace, GFP_NOFS);
ctx = zstd_init_dctx(workspace, zstd_dctx_workspace_bound());
ret = zstd_decompress_dctx(ctx,
dst_data, dst_len,
src_data.b + 4, real_src_len);
mempool_free(workspace, &c->decompress_workspace);
if (ret != dst_len)
goto err;
break;
}
default:
BUG();
}
ret = 0;
out:
bio_unmap_or_unbounce(c, src_data);
return ret;
err:
ret = -EIO;
goto out;
}
int bch2_bio_uncompress_inplace(struct bch_fs *c, struct bio *bio,
struct bch_extent_crc_unpacked *crc)
{
struct bbuf data = { NULL };
size_t dst_len = crc->uncompressed_size << 9;
/* bio must own its pages: */
BUG_ON(!bio->bi_vcnt);
BUG_ON(DIV_ROUND_UP(crc->live_size, PAGE_SECTORS) > bio->bi_max_vecs);
if (crc->uncompressed_size << 9 > c->opts.encoded_extent_max ||
crc->compressed_size << 9 > c->opts.encoded_extent_max) {
bch_err(c, "error rewriting existing data: extent too big");
return -EIO;
}
data = __bounce_alloc(c, dst_len, WRITE);
if (__bio_uncompress(c, bio, data.b, *crc)) {
if (!c->opts.no_data_io)
bch_err(c, "error rewriting existing data: decompression error");
bio_unmap_or_unbounce(c, data);
return -EIO;
}
/*
* XXX: don't have a good way to assert that the bio was allocated with
* enough space, we depend on bch2_move_extent doing the right thing
*/
bio->bi_iter.bi_size = crc->live_size << 9;
memcpy_to_bio(bio, bio->bi_iter, data.b + (crc->offset << 9));
crc->csum_type = 0;
crc->compression_type = 0;
crc->compressed_size = crc->live_size;
crc->uncompressed_size = crc->live_size;
crc->offset = 0;
crc->csum = (struct bch_csum) { 0, 0 };
bio_unmap_or_unbounce(c, data);
return 0;
}
int bch2_bio_uncompress(struct bch_fs *c, struct bio *src,
struct bio *dst, struct bvec_iter dst_iter,
struct bch_extent_crc_unpacked crc)
{
struct bbuf dst_data = { NULL };
size_t dst_len = crc.uncompressed_size << 9;
int ret;
if (crc.uncompressed_size << 9 > c->opts.encoded_extent_max ||
crc.compressed_size << 9 > c->opts.encoded_extent_max)
return -EIO;
dst_data = dst_len == dst_iter.bi_size
? __bio_map_or_bounce(c, dst, dst_iter, WRITE)
: __bounce_alloc(c, dst_len, WRITE);
ret = __bio_uncompress(c, src, dst_data.b, crc);
if (ret)
goto err;
if (dst_data.type != BB_NONE &&
dst_data.type != BB_VMAP)
memcpy_to_bio(dst, dst_iter, dst_data.b + (crc.offset << 9));
err:
bio_unmap_or_unbounce(c, dst_data);
return ret;
}
static int attempt_compress(struct bch_fs *c,
void *workspace,
void *dst, size_t dst_len,
void *src, size_t src_len,
struct bch_compression_opt compression)
{
enum bch_compression_type compression_type =
__bch2_compression_opt_to_type[compression.type];
switch (compression_type) {
case BCH_COMPRESSION_TYPE_lz4:
if (compression.level < LZ4HC_MIN_CLEVEL) {
int len = src_len;
int ret = LZ4_compress_destSize(
src, dst,
&len, dst_len,
workspace);
if (len < src_len)
return -len;
return ret;
} else {
int ret = LZ4_compress_HC(
src, dst,
src_len, dst_len,
compression.level,
workspace);
return ret ?: -1;
}
case BCH_COMPRESSION_TYPE_gzip: {
z_stream strm = {
.next_in = src,
.avail_in = src_len,
.next_out = dst,
.avail_out = dst_len,
};
zlib_set_workspace(&strm, workspace);
zlib_deflateInit2(&strm,
compression.level
? clamp_t(unsigned, compression.level,
Z_BEST_SPEED, Z_BEST_COMPRESSION)
: Z_DEFAULT_COMPRESSION,
Z_DEFLATED, -MAX_WBITS, DEF_MEM_LEVEL,
Z_DEFAULT_STRATEGY);
if (zlib_deflate(&strm, Z_FINISH) != Z_STREAM_END)
return 0;
if (zlib_deflateEnd(&strm) != Z_OK)
return 0;
return strm.total_out;
}
case BCH_COMPRESSION_TYPE_zstd: {
/*
* rescale:
* zstd max compression level is 22, our max level is 15
*/
unsigned level = min((compression.level * 3) / 2, zstd_max_clevel());
ZSTD_parameters params = zstd_get_params(level, c->opts.encoded_extent_max);
ZSTD_CCtx *ctx = zstd_init_cctx(workspace,
zstd_cctx_workspace_bound(&params.cParams));
/*
* ZSTD requires that when we decompress we pass in the exact
* compressed size - rounding it up to the nearest sector
* doesn't work, so we use the first 4 bytes of the buffer for
* that.
*
* Additionally, the ZSTD code seems to have a bug where it will
* write just past the end of the buffer - so subtract a fudge
* factor (7 bytes) from the dst buffer size to account for
* that.
*/
size_t len = zstd_compress_cctx(ctx,
dst + 4, dst_len - 4 - 7,
src, src_len,
&c->zstd_params);
if (zstd_is_error(len))
return 0;
*((__le32 *) dst) = cpu_to_le32(len);
return len + 4;
}
default:
BUG();
}
}
static unsigned __bio_compress(struct bch_fs *c,
struct bio *dst, size_t *dst_len,
struct bio *src, size_t *src_len,
struct bch_compression_opt compression)
{
struct bbuf src_data = { NULL }, dst_data = { NULL };
void *workspace;
enum bch_compression_type compression_type =
__bch2_compression_opt_to_type[compression.type];
unsigned pad;
int ret = 0;
BUG_ON(compression_type >= BCH_COMPRESSION_TYPE_NR);
BUG_ON(!mempool_initialized(&c->compress_workspace[compression_type]));
/* If it's only one block, don't bother trying to compress: */
if (src->bi_iter.bi_size <= c->opts.block_size)
return BCH_COMPRESSION_TYPE_incompressible;
dst_data = bio_map_or_bounce(c, dst, WRITE);
src_data = bio_map_or_bounce(c, src, READ);
workspace = mempool_alloc(&c->compress_workspace[compression_type], GFP_NOFS);
*src_len = src->bi_iter.bi_size;
*dst_len = dst->bi_iter.bi_size;
/*
* XXX: this algorithm sucks when the compression code doesn't tell us
* how much would fit, like LZ4 does:
*/
while (1) {
if (*src_len <= block_bytes(c)) {
ret = -1;
break;
}
ret = attempt_compress(c, workspace,
dst_data.b, *dst_len,
src_data.b, *src_len,
compression);
if (ret > 0) {
*dst_len = ret;
ret = 0;
break;
}
/* Didn't fit: should we retry with a smaller amount? */
if (*src_len <= *dst_len) {
ret = -1;
break;
}
/*
* If ret is negative, it's a hint as to how much data would fit
*/
BUG_ON(-ret >= *src_len);
if (ret < 0)
*src_len = -ret;
else
*src_len -= (*src_len - *dst_len) / 2;
*src_len = round_down(*src_len, block_bytes(c));
}
mempool_free(workspace, &c->compress_workspace[compression_type]);
if (ret)
goto err;
/* Didn't get smaller: */
if (round_up(*dst_len, block_bytes(c)) >= *src_len)
goto err;
pad = round_up(*dst_len, block_bytes(c)) - *dst_len;
memset(dst_data.b + *dst_len, 0, pad);
*dst_len += pad;
if (dst_data.type != BB_NONE &&
dst_data.type != BB_VMAP)
memcpy_to_bio(dst, dst->bi_iter, dst_data.b);
BUG_ON(!*dst_len || *dst_len > dst->bi_iter.bi_size);
BUG_ON(!*src_len || *src_len > src->bi_iter.bi_size);
BUG_ON(*dst_len & (block_bytes(c) - 1));
BUG_ON(*src_len & (block_bytes(c) - 1));
ret = compression_type;
out:
bio_unmap_or_unbounce(c, src_data);
bio_unmap_or_unbounce(c, dst_data);
return ret;
err:
ret = BCH_COMPRESSION_TYPE_incompressible;
goto out;
}
unsigned bch2_bio_compress(struct bch_fs *c,
struct bio *dst, size_t *dst_len,
struct bio *src, size_t *src_len,
unsigned compression_opt)
{
unsigned orig_dst = dst->bi_iter.bi_size;
unsigned orig_src = src->bi_iter.bi_size;
unsigned compression_type;
/* Don't consume more than BCH_ENCODED_EXTENT_MAX from @src: */
src->bi_iter.bi_size = min_t(unsigned, src->bi_iter.bi_size,
c->opts.encoded_extent_max);
/* Don't generate a bigger output than input: */
dst->bi_iter.bi_size = min(dst->bi_iter.bi_size, src->bi_iter.bi_size);
compression_type =
__bio_compress(c, dst, dst_len, src, src_len,
bch2_compression_decode(compression_opt));
dst->bi_iter.bi_size = orig_dst;
src->bi_iter.bi_size = orig_src;
return compression_type;
}
static int __bch2_fs_compress_init(struct bch_fs *, u64);
#define BCH_FEATURE_none 0
static const unsigned bch2_compression_opt_to_feature[] = {
#define x(t, n) [BCH_COMPRESSION_OPT_##t] = BCH_FEATURE_##t,
BCH_COMPRESSION_OPTS()
#undef x
};
#undef BCH_FEATURE_none
static int __bch2_check_set_has_compressed_data(struct bch_fs *c, u64 f)
{
int ret = 0;
if ((c->sb.features & f) == f)
return 0;
mutex_lock(&c->sb_lock);
if ((c->sb.features & f) == f) {
mutex_unlock(&c->sb_lock);
return 0;
}
ret = __bch2_fs_compress_init(c, c->sb.features|f);
if (ret) {
mutex_unlock(&c->sb_lock);
return ret;
}
c->disk_sb.sb->features[0] |= cpu_to_le64(f);
bch2_write_super(c);
mutex_unlock(&c->sb_lock);
return 0;
}
int bch2_check_set_has_compressed_data(struct bch_fs *c,
unsigned compression_opt)
{
unsigned compression_type = bch2_compression_decode(compression_opt).type;
BUG_ON(compression_type >= ARRAY_SIZE(bch2_compression_opt_to_feature));
return compression_type
? __bch2_check_set_has_compressed_data(c,
1ULL << bch2_compression_opt_to_feature[compression_type])
: 0;
}
void bch2_fs_compress_exit(struct bch_fs *c)
{
unsigned i;
mempool_exit(&c->decompress_workspace);
for (i = 0; i < ARRAY_SIZE(c->compress_workspace); i++)
mempool_exit(&c->compress_workspace[i]);
mempool_exit(&c->compression_bounce[WRITE]);
mempool_exit(&c->compression_bounce[READ]);
}
static int __bch2_fs_compress_init(struct bch_fs *c, u64 features)
{
size_t decompress_workspace_size = 0;
ZSTD_parameters params = zstd_get_params(zstd_max_clevel(),
c->opts.encoded_extent_max);
struct {
unsigned feature;
enum bch_compression_type type;
size_t compress_workspace;
size_t decompress_workspace;
} compression_types[] = {
{ BCH_FEATURE_lz4, BCH_COMPRESSION_TYPE_lz4,
max_t(size_t, LZ4_MEM_COMPRESS, LZ4HC_MEM_COMPRESS),
0 },
{ BCH_FEATURE_gzip, BCH_COMPRESSION_TYPE_gzip,
zlib_deflate_workspacesize(MAX_WBITS, DEF_MEM_LEVEL),
zlib_inflate_workspacesize(), },
{ BCH_FEATURE_zstd, BCH_COMPRESSION_TYPE_zstd,
zstd_cctx_workspace_bound(&params.cParams),
zstd_dctx_workspace_bound() },
}, *i;
bool have_compressed = false;
c->zstd_params = params;
for (i = compression_types;
i < compression_types + ARRAY_SIZE(compression_types);
i++)
have_compressed |= (features & (1 << i->feature)) != 0;
if (!have_compressed)
return 0;
if (!mempool_initialized(&c->compression_bounce[READ]) &&
mempool_init_kvpmalloc_pool(&c->compression_bounce[READ],
1, c->opts.encoded_extent_max))
return -BCH_ERR_ENOMEM_compression_bounce_read_init;
if (!mempool_initialized(&c->compression_bounce[WRITE]) &&
mempool_init_kvpmalloc_pool(&c->compression_bounce[WRITE],
1, c->opts.encoded_extent_max))
return -BCH_ERR_ENOMEM_compression_bounce_write_init;
for (i = compression_types;
i < compression_types + ARRAY_SIZE(compression_types);
i++) {
decompress_workspace_size =
max(decompress_workspace_size, i->decompress_workspace);
if (!(features & (1 << i->feature)))
continue;
if (mempool_initialized(&c->compress_workspace[i->type]))
continue;
if (mempool_init_kvpmalloc_pool(
&c->compress_workspace[i->type],
1, i->compress_workspace))
return -BCH_ERR_ENOMEM_compression_workspace_init;
}
if (!mempool_initialized(&c->decompress_workspace) &&
mempool_init_kvpmalloc_pool(&c->decompress_workspace,
1, decompress_workspace_size))
return -BCH_ERR_ENOMEM_decompression_workspace_init;
return 0;
}
static u64 compression_opt_to_feature(unsigned v)
{
unsigned type = bch2_compression_decode(v).type;
return BIT_ULL(bch2_compression_opt_to_feature[type]);
}
int bch2_fs_compress_init(struct bch_fs *c)
{
u64 f = c->sb.features;
f |= compression_opt_to_feature(c->opts.compression);
f |= compression_opt_to_feature(c->opts.background_compression);
return __bch2_fs_compress_init(c, f);
}
int bch2_opt_compression_parse(struct bch_fs *c, const char *_val, u64 *res,
struct printbuf *err)
{
char *val = kstrdup(_val, GFP_KERNEL);
char *p = val, *type_str, *level_str;
struct bch_compression_opt opt = { 0 };
int ret;
if (!val)
return -ENOMEM;
type_str = strsep(&p, ":");
level_str = p;
ret = match_string(bch2_compression_opts, -1, type_str);
if (ret < 0 && err)
prt_str(err, "invalid compression type");
if (ret < 0)
goto err;
opt.type = ret;
if (level_str) {
unsigned level;
ret = kstrtouint(level_str, 10, &level);
if (!ret && !opt.type && level)
ret = -EINVAL;
if (!ret && level > 15)
ret = -EINVAL;
if (ret < 0 && err)
prt_str(err, "invalid compression level");
if (ret < 0)
goto err;
opt.level = level;
}
*res = bch2_compression_encode(opt);
err:
kfree(val);
return ret;
}
void bch2_opt_compression_to_text(struct printbuf *out,
struct bch_fs *c,
struct bch_sb *sb,
u64 v)
{
struct bch_compression_opt opt = bch2_compression_decode(v);
prt_str(out, bch2_compression_opts[opt.type]);
if (opt.level)
prt_printf(out, ":%u", opt.level);
}
int bch2_opt_compression_validate(u64 v, struct printbuf *err)
{
if (!bch2_compression_opt_valid(v)) {
prt_printf(err, "invalid compression opt %llu", v);
return -BCH_ERR_invalid_sb_opt_compression;
}
return 0;
}