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btrfs-progs: mkfs: add lzo to --compress option
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Allows --compress to work with lzo.

Signed-off-by: Mark Harmstone <[email protected]>
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@maharmstone
maharmstone committed Oct 15, 2024
1 parent c614436 commit 094d7ef
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Showing 3 changed files with 190 additions and 6 deletions.
2 changes: 1 addition & 1 deletion Documentation/mkfs.btrfs.rst
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Original file line number Diff line number Diff line change
Expand Up @@ -214,7 +214,7 @@ OPTIONS
--compress <algo>:<level>
Try to compress files when using *--rootdir*. Supported values for *algo* are
*no* (the default), *zlib*, and *zstd*. The optional value *level* is a
*no* (the default), *zlib*, *lzo*, and *zstd*. The optional value *level* is a
compression level, from 1 to 9 for ZLIB and from 1 to 15 for ZSTD.

As with the kernel, :command:`mkfs.btrfs` won't write compressed extents when
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2 changes: 1 addition & 1 deletion mkfs/main.c
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Original file line number Diff line number Diff line change
Expand Up @@ -443,7 +443,7 @@ static const char * const mkfs_usage[] = {
OPTLINE("-u|--subvol TYPE:SUBDIR", "create SUBDIR as subvolume rather than normal directory, can be specified multiple times"),
OPTLINE("--shrink", "(with --rootdir) shrink the filled filesystem to minimal size"),
OPTLINE("-K|--nodiscard", "do not perform whole device TRIM"),
OPTLINE("--compress ALGO:LEVEL", "compression algorithm and level to use; ALGO can be no (default), zlib, zstd"),
OPTLINE("--compress ALGO:LEVEL", "compression algorithm and level to use; ALGO can be no (default), zlib, lzo, zstd"),
OPTLINE("-f|--force", "force overwrite of existing filesystem"),
"General:",
OPTLINE("-q|--quiet", "no messages except errors"),
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192 changes: 188 additions & 4 deletions mkfs/rootdir.c
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Original file line number Diff line number Diff line change
Expand Up @@ -32,6 +32,7 @@
#include <zstd_errors.h>
#endif
#include <zlib.h>
#include <lzo/lzo1x.h>
#include "kernel-lib/sizes.h"
#include "kernel-shared/accessors.h"
#include "kernel-shared/uapi/btrfs_tree.h"
Expand All @@ -56,6 +57,8 @@
#define ZSTD_BTRFS_DEFAULT_LEVEL 3
#define ZSTD_BTRFS_MAX_LEVEL 15

#define LZO_LEN 4

static u32 fs_block_size;

/*
Expand Down Expand Up @@ -445,6 +448,77 @@ static ssize_t zlib_compress_extent(struct btrfs_inode_item *btrfs_inode,
return 0;
}

static ssize_t lzo_compress_extent(struct btrfs_inode_item *btrfs_inode,
u32 sectorsize, const void *in_buf,
size_t in_size, void *out_buf, char *wrkmem)
{
int ret;
unsigned int sectors;
u32 total_size, out_pos;
u64 flags;

out_pos = LZO_LEN;
total_size = LZO_LEN;
sectors = DIV_ROUND_UP(in_size, sectorsize);

for (unsigned int i = 0; i < sectors; i++) {
size_t in_len, out_len, new_pos;
u32 padding;

in_len = min((size_t)sectorsize, in_size - (i * sectorsize));

ret = lzo1x_1_compress(in_buf + (i * sectorsize), in_len,
out_buf + out_pos + LZO_LEN, &out_len,
wrkmem);
if (ret) {
error("lzo1x_1_compress returned %i", ret);
return -EINVAL;
}

put_unaligned_le32(out_len, out_buf + out_pos);

new_pos = out_pos + LZO_LEN + out_len;

/* Make sure that our header doesn't cross a sector boundary. */
if (new_pos / sectorsize != (new_pos + LZO_LEN - 1) / sectorsize)
padding = round_up(new_pos, LZO_LEN) - new_pos;
else
padding = 0;

out_pos += out_len + LZO_LEN + padding;
total_size += out_len + LZO_LEN + padding;

/* Follow kernel in trying to compress the first three sectors,
* then giving up if the output isn't any smaller. */
if (i >= 3 && total_size > i * sectorsize) {
total_size = 0;
goto out;
}
}

if (total_size > in_size) {
total_size = 0;
goto out;
}

put_unaligned_le32(total_size, out_buf);

out:
flags = btrfs_stack_inode_flags(btrfs_inode);

if (total_size == 0) {
if (!(flags & BTRFS_INODE_COMPRESS)) {
flags |= BTRFS_INODE_NOCOMPRESS;
btrfs_set_stack_inode_flags(btrfs_inode, flags);
}
} else {
flags |= BTRFS_INODE_COMPRESS;
btrfs_set_stack_inode_flags(btrfs_inode, flags);
}

return total_size;
}

#if COMPRESSION_ZSTD
static ssize_t zstd_compress_extent(struct btrfs_inode_item *btrfs_inode,
u32 sectorsize, const void *in_buf,
Expand Down Expand Up @@ -557,7 +631,7 @@ static int read_and_write_extent(struct btrfs_trans_handle *trans,
struct btrfs_inode_item *btrfs_inode,
u64 objectid, int fd, u64 file_pos, char *buf,
u64 size, const char *path_name,
char *comp_buf)
char *comp_buf, char *wrkmem)
{
int ret;
u32 sectorsize = root->fs_info->sectorsize;
Expand Down Expand Up @@ -601,6 +675,11 @@ static int read_and_write_extent(struct btrfs_trans_handle *trans,
buf, bytes_read,
comp_buf);
break;
case BTRFS_COMPRESS_LZO:
comp_ret = lzo_compress_extent(btrfs_inode, sectorsize,
buf, bytes_read,
comp_buf, wrkmem);
break;
#if COMPRESSION_ZSTD
case BTRFS_COMPRESS_ZSTD:
comp_ret = zstd_compress_extent(btrfs_inode, sectorsize,
Expand Down Expand Up @@ -658,6 +737,11 @@ static int read_and_write_extent(struct btrfs_trans_handle *trans,
features |= BTRFS_FEATURE_INCOMPAT_COMPRESS_ZSTD;
btrfs_set_super_incompat_flags(trans->fs_info->super_copy,
features);
} else if (g_compression == BTRFS_COMPRESS_LZO) {
features = btrfs_super_incompat_flags(trans->fs_info->super_copy);
features |= BTRFS_FEATURE_INCOMPAT_COMPRESS_LZO;
btrfs_set_super_incompat_flags(trans->fs_info->super_copy,
features);
}
} else {
to_write = round_up(to_read, sectorsize);
Expand Down Expand Up @@ -754,6 +838,56 @@ static int zlib_compress_inline_extent(char *buf, u64 size, char **comp_buf,
return ret;
}

static u32 lzo_max_outlen(u32 inlen) {
/* Return the worst-case output length for LZO. Formula comes from
* LZO.FAQ. */
return inlen + (inlen / 16) + 64 + 3;
}

static int lzo_compress_inline_extent(void *buf, u64 size, char **comp_buf,
u64 *comp_size, char *wrkmem)
{
int ret;
size_t out_len, out_size;
void *out = NULL;

out_size = LZO_LEN + LZO_LEN + lzo_max_outlen(size);

out = malloc(out_size);
if (!out) {
error_msg(ERROR_MSG_MEMORY, NULL);
ret = -ENOMEM;
goto out;
}

ret = lzo1x_1_compress(buf, size, out + LZO_LEN + LZO_LEN, &out_len,
wrkmem);
if (ret) {
error("lzo1x_1_compress returned %i", ret);
ret = -EINVAL;
goto out;
}

if (out_len + LZO_LEN + LZO_LEN >= size) {
ret = 0;
goto out;
}

put_unaligned_le32(out_len + LZO_LEN + LZO_LEN, out);
put_unaligned_le32(out_len, out + LZO_LEN);

*comp_buf = out;
*comp_size = out_len + LZO_LEN + LZO_LEN;

ret = 1;

out:
if (ret != 1)
free(out);

return ret;
}

#if COMPRESSION_ZSTD
static int zstd_compress_inline_extent(char *buf, u64 size, char **comp_buf,
u64 *comp_size)
Expand Down Expand Up @@ -840,7 +974,7 @@ static int add_file_items(struct btrfs_trans_handle *trans,
ssize_t ret_read;
u32 sectorsize = fs_info->sectorsize;
u64 file_pos = 0;
char *buf = NULL, *comp_buf = NULL;
char *buf = NULL, *comp_buf = NULL, *wrkmem = NULL;
int fd;

if (st->st_size == 0)
Expand All @@ -852,6 +986,14 @@ static int add_file_items(struct btrfs_trans_handle *trans,
return ret;
}

if (g_compression == BTRFS_COMPRESS_LZO) {
wrkmem = malloc(LZO1X_1_MEM_COMPRESS);
if (!wrkmem) {
ret = -ENOMEM;
goto end;
}
}

if (st->st_size <= BTRFS_MAX_INLINE_DATA_SIZE(fs_info) &&
st->st_size < sectorsize) {
char *buffer = malloc(st->st_size);
Expand All @@ -877,6 +1019,13 @@ static int add_file_items(struct btrfs_trans_handle *trans,
if (ret < 0)
goto end;
break;
case BTRFS_COMPRESS_LZO:
ret = lzo_compress_inline_extent(buffer, st->st_size,
&comp_buf, &comp_size,
wrkmem);
if (ret < 0)
goto end;
break;
#if COMPRESSION_ZSTD
case BTRFS_COMPRESS_ZSTD:
ret = zstd_compress_inline_extent(buffer, st->st_size,
Expand Down Expand Up @@ -913,7 +1062,40 @@ static int add_file_items(struct btrfs_trans_handle *trans,
goto end;
}

if (g_compression != BTRFS_COMPRESS_NONE) {
if (g_compression == BTRFS_COMPRESS_LZO) {
unsigned int sectors;
size_t comp_buf_len;

/* LZO helpfully doesn't provide a way to specify the output
* buffer size, so we need to allocate for the worst-case
* scenario to avoid buffer overruns.
*
* 4 bytes for the total size
* And for each sector:
* - 4 bytes for the compressed sector size
* - the worst-case output size
* - 3 bytes for possible padding
*/

sectors = BTRFS_MAX_COMPRESSED / sectorsize;

comp_buf_len = LZO_LEN;
comp_buf_len += (LZO_LEN + lzo_max_outlen(sectorsize) +
LZO_LEN - 1) * sectors;

comp_buf = malloc(comp_buf_len);
if (!comp_buf) {
ret = -ENOMEM;
goto end;
}

ret = lzo_init();
if (ret) {
error("lzo_init returned %i", ret);
ret = -EINVAL;
goto end;
}
} else if (g_compression != BTRFS_COMPRESS_NONE) {
comp_buf = malloc(BTRFS_MAX_COMPRESSED);
if (!comp_buf) {
ret = -ENOMEM;
Expand All @@ -924,14 +1106,15 @@ static int add_file_items(struct btrfs_trans_handle *trans,
while (file_pos < st->st_size) {
ret = read_and_write_extent(trans, root, btrfs_inode, objectid,
fd, file_pos, buf, st->st_size,
path_name, comp_buf);
path_name, comp_buf, wrkmem);
if (ret < 0)
break;

file_pos += ret;
}

end:
free(wrkmem);
free(comp_buf);
free(buf);
close(fd);
Expand Down Expand Up @@ -1352,6 +1535,7 @@ int btrfs_mkfs_fill_dir(struct btrfs_trans_handle *trans, const char *source_dir

switch (compression) {
case BTRFS_COMPRESS_NONE:
case BTRFS_COMPRESS_LZO:
break;
case BTRFS_COMPRESS_ZLIB:
if (compression_level > ZLIB_BTRFS_MAX_LEVEL)
Expand Down

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