On Mon, Nov 12, 2018 at 02:14:46PM -0800, Nick Terrell wrote:
> - Adds zstd support to the btrfs module.
> - Adds a test case for btrfs zstd support.
> - Changes top_srcdir to srcdir in the btrfs module's lzo include
> following comments from Daniel Kiper about the zstd include.
>
> Tested on Ubuntu-18.04 with a btrfs /boot partition with and without zstd
> compression. A test case was also added to the test suite that fails before
> the patch, and passes after.
>
> Signed-off-by: Nick Terrell <terre...@fb.com>
Code mostly LGTM. However, coding style in grub-core/fs/btrfs.c is
largely incorrect. Please take a look below.
> ---
> v1 -> v2:
> - Fix comments from Daniel Kiper.
>
> v2 -> v3:
> - Use grub_error() to set grub_errno in grub_btrfs_zstd_decompress().
> - Fix style and formatting comments.
>
> v3 -> v4:
> - Use attribute unused.
>
> v4 -> v5:
> - Add zstd's module.c to Makefile.util.def.
> - Clarify some error logging.
> - Explain why I changed lzo's include.
>
> Makefile.util.def | 11 +++-
> grub-core/Makefile.core.def | 2 +-
> grub-core/fs/btrfs.c | 108 ++++++++++++++++++++++++++++++++++-
> tests/btrfs_test.in | 1 +
> tests/util/grub-fs-tester.in | 2 +-
> 5 files changed, 120 insertions(+), 4 deletions(-)
>
> diff --git a/Makefile.util.def b/Makefile.util.def
> index 9ae45f351..a0495a87f 100644
> --- a/Makefile.util.def
> +++ b/Makefile.util.def
> @@ -54,7 +54,7 @@ library = {
> library = {
> name = libgrubmods.a;
> cflags = '-fno-builtin -Wno-undef';
> - cppflags = '-I$(top_srcdir)/grub-core/lib/minilzo
> -I$(srcdir)/grub-core/lib/xzembed -DMINILZO_HAVE_CONFIG_H';
> + cppflags = '-I$(srcdir)/grub-core/lib/minilzo
> -I$(srcdir)/grub-core/lib/xzembed -I$(srcdir)/grub-core/lib/zstd
> -DMINILZO_HAVE_CONFIG_H';
>
> common_nodist = grub_script.tab.c;
> common_nodist = grub_script.yy.c;
> @@ -165,6 +165,15 @@ library = {
> common = grub-core/lib/xzembed/xz_dec_bcj.c;
> common = grub-core/lib/xzembed/xz_dec_lzma2.c;
> common = grub-core/lib/xzembed/xz_dec_stream.c;
> + common = grub-core/lib/zstd/debug.c;
> + common = grub-core/lib/zstd/entropy_common.c;
> + common = grub-core/lib/zstd/error_private.c;
> + common = grub-core/lib/zstd/fse_decompress.c;
> + common = grub-core/lib/zstd/huf_decompress.c;
> + common = grub-core/lib/zstd/module.c;
> + common = grub-core/lib/zstd/xxhash.c;
> + common = grub-core/lib/zstd/zstd_common.c;
> + common = grub-core/lib/zstd/zstd_decompress.c;
> };
>
> program = {
> diff --git a/grub-core/Makefile.core.def b/grub-core/Makefile.core.def
> index 829e7bb57..2d75c4daf 100644
> --- a/grub-core/Makefile.core.def
> +++ b/grub-core/Makefile.core.def
> @@ -1291,7 +1291,7 @@ module = {
> common = fs/btrfs.c;
> common = lib/crc.c;
> cflags = '$(CFLAGS_POSIX) -Wno-undef';
> - cppflags = '-I$(srcdir)/lib/posix_wrap -I$(srcdir)/lib/minilzo
> -DMINILZO_HAVE_CONFIG_H';
> + cppflags = '-I$(srcdir)/lib/posix_wrap -I$(srcdir)/lib/minilzo
> -I$(srcdir)/lib/zstd -DMINILZO_HAVE_CONFIG_H';
> };
>
> module = {
> diff --git a/grub-core/fs/btrfs.c b/grub-core/fs/btrfs.c
> index cac9ef588..59198f17a 100644
> --- a/grub-core/fs/btrfs.c
> +++ b/grub-core/fs/btrfs.c
> @@ -17,6 +17,8 @@
> * along with GRUB. If not, see <http://www.gnu.org/licenses/>.
> */
>
> +#define ZSTD_STATIC_LINKING_ONLY
Hmmm... AIUI this disables some external references but the name of
constant is confusing. Could you add a comment before it? Just what
it does here.
> +
> #include <grub/err.h>
> #include <grub/file.h>
> #include <grub/mm.h>
> @@ -27,6 +29,7 @@
> #include <grub/lib/crc.h>
> #include <grub/deflate.h>
> #include <minilzo.h>
> +#include <zstd.h>
> #include <grub/i18n.h>
> #include <grub/btrfs.h>
> #include <grub/crypto.h>
> @@ -47,6 +50,9 @@ GRUB_MOD_LICENSE ("GPLv3+");
> #define GRUB_BTRFS_LZO_BLOCK_MAX_CSIZE (GRUB_BTRFS_LZO_BLOCK_SIZE + \
> (GRUB_BTRFS_LZO_BLOCK_SIZE / 16) + 64 + 3)
>
> +#define ZSTD_BTRFS_MAX_WINDOWLOG 17
> +#define ZSTD_BTRFS_MAX_INPUT (1 << ZSTD_BTRFS_MAX_WINDOWLOG)
> +
> typedef grub_uint8_t grub_btrfs_checksum_t[0x20];
> typedef grub_uint16_t grub_btrfs_uuid_t[8];
>
> @@ -217,6 +223,7 @@ struct grub_btrfs_extent_data
> #define GRUB_BTRFS_COMPRESSION_NONE 0
> #define GRUB_BTRFS_COMPRESSION_ZLIB 1
> #define GRUB_BTRFS_COMPRESSION_LZO 2
> +#define GRUB_BTRFS_COMPRESSION_ZSTD 3
>
> #define GRUB_BTRFS_OBJECT_ID_CHUNK 0x100
>
> @@ -1216,6 +1223,91 @@ grub_btrfs_read_inode (struct grub_btrfs_data *data,
> return grub_btrfs_read_logical (data, elemaddr, inode, sizeof (*inode), 0);
> }
>
> +static void* grub_zstd_malloc (void* state __attribute__((unused)), size_t
> size)
> +{
> + return grub_malloc (size);
Four spaces instead of tab.
> +}
> +
> +static void grub_zstd_free (void* state __attribute__((unused)), void*
> address)
> +{
> + return grub_free (address);
Ditto.
> +}
> +
> +static ZSTD_customMem grub_zstd_allocator (void)
> +{
> + ZSTD_customMem allocator;
> +
> + allocator.customAlloc = &grub_zstd_malloc;
> + allocator.customFree = &grub_zstd_free;
> + allocator.opaque = NULL;
> +
> + return allocator;
Like above and below... Leading tabs can be used if there are more than 8
spaces.
> +}
> +
> +static grub_ssize_t
> +grub_btrfs_zstd_decompress (char *ibuf, grub_size_t isize, grub_off_t off,
> + char *obuf, grub_size_t osize)
> +{
> + void *allocated = NULL;
> + char *otmpbuf = obuf;
> + grub_size_t otmpsize = osize;
> + ZSTD_DCtx *dctx = NULL;
> + grub_size_t zstd_ret;
> + grub_ssize_t ret = -1;
> +
> + /*
> + * Zstd will fail if it can't fit the entire output in the destination
> + * buffer, so if osize isn't large enough, allocate a temporary buffer.
> + */
Except leading tabs comments are good.
> + if (otmpsize < ZSTD_BTRFS_MAX_INPUT) {
Curly bracket is in wrong place.
> + allocated = grub_malloc (ZSTD_BTRFS_MAX_INPUT);
> + if (!allocated) {
Ditto.
> + grub_error (GRUB_ERR_OUT_OF_MEMORY, "failed to allocate
> a zstd buffer");
> + goto err;
> + }
Ditto.
> + otmpbuf = (char*)allocated;
> + otmpsize = ZSTD_BTRFS_MAX_INPUT;
> + }
Ditto and below...
> + /* Create the ZSTD_DCtx. */
> + dctx = ZSTD_createDCtx_advanced (grub_zstd_allocator ());
> + if (!dctx) {
> + /* ZSTD_createDCtx_advanced() only fails if it is out of
> memory. */
> + grub_error (GRUB_ERR_OUT_OF_MEMORY, "failed to create a zstd
> context");
> + goto err;
> + }
> +
> + /*
> + * Get the real input size, there may be junk at the
> + * end of the frame.
> + */
> + isize = ZSTD_findFrameCompressedSize (ibuf, isize);
> + if (ZSTD_isError (isize)) {
> + grub_error (GRUB_ERR_BAD_COMPRESSED_DATA, "zstd data
> corrupted");
> + goto err;
> + }
> +
> + /* Decompress and check for errors. */
> + zstd_ret = ZSTD_decompressDCtx (dctx, otmpbuf, otmpsize, ibuf, isize);
> + if (ZSTD_isError (zstd_ret)) {
> + grub_error (GRUB_ERR_BAD_COMPRESSED_DATA, "zstd data
> corrupted");
> + goto err;
> + }
> +
> + /*
> + * Move the requested data into the obuf. obuf may be equal
> + * to otmpbuf, which is why grub_memmove() is required.
> + */
> + grub_memmove (obuf, otmpbuf + off, osize);
> + ret = osize;
> +
> +err:
> + grub_free (allocated);
> + ZSTD_freeDCtx (dctx);
> +
> + return ret;
> +}
> +
> static grub_ssize_t
> grub_btrfs_lzo_decompress(char *ibuf, grub_size_t isize, grub_off_t off,
> char *obuf, grub_size_t osize)
> @@ -1391,7 +1483,8 @@ grub_btrfs_extent_read (struct grub_btrfs_data *data,
>
> if (data->extent->compression != GRUB_BTRFS_COMPRESSION_NONE
> && data->extent->compression != GRUB_BTRFS_COMPRESSION_ZLIB
> - && data->extent->compression != GRUB_BTRFS_COMPRESSION_LZO)
> + && data->extent->compression != GRUB_BTRFS_COMPRESSION_LZO
> + && data->extent->compression != GRUB_BTRFS_COMPRESSION_ZSTD)
> {
> grub_error (GRUB_ERR_NOT_IMPLEMENTED_YET,
> "compression type 0x%x not supported",
> @@ -1431,6 +1524,15 @@ grub_btrfs_extent_read (struct grub_btrfs_data *data,
> != (grub_ssize_t) csize)
> return -1;
> }
> + else if (data->extent->compression == GRUB_BTRFS_COMPRESSION_ZSTD)
> + {
...and here it is OK.
> + if (grub_btrfs_zstd_decompress(data->extent->inl, data->extsize -
> + ((grub_uint8_t *) data->extent->inl
> + - (grub_uint8_t *) data->extent),
> + extoff, buf, csize)
> + != (grub_ssize_t) csize)
> + return -1;
> + }
Same here.
Daniel
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