diff mbox series

[v4,2/2] btrfs: Add zstd support to grub btrfs

Message ID 20181031175617.230241-3-terrelln@fb.com (mailing list archive)
State New, archived
Headers show
Series btrfs: Add zstd support to grub btrfs | expand

Commit Message

Nick Terrell Oct. 31, 2018, 5:56 p.m. UTC
Adds zstd support to the btrfs module.

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 <terrelln@fb.com>
---
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.

 Makefile.util.def            |  10 +++-
 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, 119 insertions(+), 4 deletions(-)

--
2.17.1

Comments

Daniel Kiper Nov. 6, 2018, 3:06 p.m. UTC | #1
On Wed, Oct 31, 2018 at 10:56:17AM -0700, Nick Terrell wrote:
> Adds zstd support to the btrfs module.
>
> 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 <terrelln@fb.com>
> ---
> 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.
>
>  Makefile.util.def            |  10 +++-
>  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, 119 insertions(+), 4 deletions(-)
>
> diff --git a/Makefile.util.def b/Makefile.util.def
> index 9ae45f351..3ce9388ae 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';

I am not strongly against s/top_srcdir/srcdir/ here. However, if you do
such things I will ask you to add a blurb why to the commit message.

[...]

> +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.
> +	 */
> +	if (otmpsize < ZSTD_BTRFS_MAX_INPUT) {
> +		allocated = grub_malloc (ZSTD_BTRFS_MAX_INPUT);
> +		if (!allocated) {
> +			goto err;

Hmmm... You fail silently. Should not you say something here?

> +		}

If above is OK then drop this curly brackets.

> +		otmpbuf = (char*)allocated;
> +		otmpsize = ZSTD_BTRFS_MAX_INPUT;
> +	}
> +
> +	/* Create the ZSTD_DCtx. */
> +	dctx = ZSTD_createDCtx_advanced (grub_zstd_allocator ());
> +	if (!dctx) {
> +		grub_error (GRUB_ERR_OUT_OF_MEMORY, "zstd out of memory");

...and here you complain. OK, but why GRUB_ERR_OUT_OF_MEMORY?
This probably applies to grub_zstd_allocator() but maybe not to
ZSTD_createDCtx_advanced(). AIUI both functions may return
different errors.

Daniel
diff mbox series

Patch

diff --git a/Makefile.util.def b/Makefile.util.def
index 9ae45f351..3ce9388ae 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 +165,14 @@  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/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 540a31f78..b09319328 100644
--- a/grub-core/Makefile.core.def
+++ b/grub-core/Makefile.core.def
@@ -1280,7 +1280,7 @@  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..8cfb997c5 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
+
 #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);
+}
+
+static void grub_zstd_free (void* state __attribute__((unused)), void* address)
+{
+	return grub_free (address);
+}
+
+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;
+}
+
+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.
+	 */
+	if (otmpsize < ZSTD_BTRFS_MAX_INPUT) {
+		allocated = grub_malloc (ZSTD_BTRFS_MAX_INPUT);
+		if (!allocated) {
+			goto err;
+		}
+		otmpbuf = (char*)allocated;
+		otmpsize = ZSTD_BTRFS_MAX_INPUT;
+	}
+
+	/* Create the ZSTD_DCtx. */
+	dctx = ZSTD_createDCtx_advanced (grub_zstd_allocator ());
+	if (!dctx) {
+		grub_error (GRUB_ERR_OUT_OF_MEMORY, "zstd out of memory");
+		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)
+	    {
+	      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;
+	    }
 	  else
 	    grub_memcpy (buf, data->extent->inl + extoff, csize);
 	  break;
@@ -1468,6 +1570,10 @@  grub_btrfs_extent_read (struct grub_btrfs_data *data,
 		ret = grub_btrfs_lzo_decompress (tmp, zsize, extoff
 				    + grub_le_to_cpu64 (data->extent->offset),
 				    buf, csize);
+	      else if (data->extent->compression == GRUB_BTRFS_COMPRESSION_ZSTD)
+		ret = grub_btrfs_zstd_decompress (tmp, zsize, extoff
+				    + grub_le_to_cpu64 (data->extent->offset),
+				    buf, csize);
 	      else
 		ret = -1;

diff --git a/tests/btrfs_test.in b/tests/btrfs_test.in
index 2b37ddd33..0c9bf3a68 100644
--- a/tests/btrfs_test.in
+++ b/tests/btrfs_test.in
@@ -18,6 +18,7 @@  fi
 "@builddir@/grub-fs-tester" btrfs
 "@builddir@/grub-fs-tester" btrfs_zlib
 "@builddir@/grub-fs-tester" btrfs_lzo
+"@builddir@/grub-fs-tester" btrfs_zstd
 "@builddir@/grub-fs-tester" btrfs_raid0
 "@builddir@/grub-fs-tester" btrfs_raid1
 "@builddir@/grub-fs-tester" btrfs_single
diff --git a/tests/util/grub-fs-tester.in b/tests/util/grub-fs-tester.in
index ef65fbc93..bc14a05ca 100644
--- a/tests/util/grub-fs-tester.in
+++ b/tests/util/grub-fs-tester.in
@@ -629,7 +629,7 @@  for LOGSECSIZE in $(range "$MINLOGSECSIZE" "$MAXLOGSECSIZE" 1); do
 		    ;;
 		x"btrfs")
 		    "mkfs.btrfs" -s $SECSIZE -L "$FSLABEL" "${MOUNTDEVICE}" ;;
-		x"btrfs_zlib" | x"btrfs_lzo")
+		x"btrfs_zlib" | x"btrfs_lzo" | x"btrfs_zstd")
 		    "mkfs.btrfs" -s $SECSIZE -L "$FSLABEL" "${MOUNTDEVICE}"
 		    MOUNTOPTS="compress=${fs/btrfs_/},"
 		    MOUNTFS="btrfs"