Add zstd support to zfs

This PR adds two new compression types, based on ZStandard:

- zstd: A basic ZStandard compression algorithm Available compression.
  Levels for zstd are zstd-1 through zstd-19, where the compression
  increases with every level, but speed decreases.

- zstd-fast: A faster version of the ZStandard compression algorithm
  zstd-fast is basically a "negative" level of zstd. The compression
  decreases with every level, but speed increases.

  Available compression levels for zstd-fast:
   - zstd-fast-1 through zstd-fast-10
   - zstd-fast-20 through zstd-fast-100 (in increments of 10)
   - zstd-fast-500 and zstd-fast-1000

For more information check the man page.

Implementation details:

Rather than treat each level of zstd as a different algorithm (as was
done historically with gzip), the block pointer `enum zio_compress`
value is simply zstd for all levels, including zstd-fast, since they all
use the same decompression function.

The compress= property (a 64bit unsigned integer) uses the lower 7 bits
to store the compression algorithm (matching the number of bits used in
a block pointer, as the 8th bit was borrowed for embedded block
pointers).  The upper bits are used to store the compression level.

It is necessary to be able to determine what compression level was used
when later reading a block back, so the concept used in LZ4, where the
first 32bits of the on-disk value are the size of the compressed data
(since the allocation is rounded up to the nearest ashift), was
extended, and we store the version of ZSTD and the level as well as the
compressed size. This value is returned when decompressing a block, so
that if the block needs to be recompressed (L2ARC, nop-write, etc), that
the same parameters will be used to result in the matching checksum.

All of the internal ZFS code ( `arc_buf_hdr_t`, `objset_t`,
`zio_prop_t`, etc.) uses the separated _compress and _complevel
variables.  Only the properties ZAP contains the combined/bit-shifted
value. The combined value is split when the compression_changed_cb()
callback is called, and sets both objset members (os_compress and
os_complevel).

The userspace tools all use the combined/bit-shifted value.

Additional notes:

zdb can now also decode the ZSTD compression header (flag -Z) and
inspect the size, version and compression level saved in that header.
For each record, if it is ZSTD compressed, the parameters of the decoded
compression header get printed.

ZSTD is included with all current tests and new tests are added
as-needed.

Per-dataset feature flags now get activated when the property is set.
If a compression algorithm requires a feature flag, zfs activates the
feature when the property is set, rather than waiting for the first
block to be born.  This is currently only used by zstd but can be
extended as needed.

Portions-Sponsored-By: The FreeBSD Foundation
Co-authored-by: Allan Jude <allanjude@freebsd.org>
Co-authored-by: Brian Behlendorf <behlendorf1@llnl.gov>
Co-authored-by: Sebastian Gottschall <s.gottschall@dd-wrt.com>
Co-authored-by: Kjeld Schouten-Lebbing <kjeld@schouten-lebbing.nl>
Co-authored-by: Michael Niewöhner <foss@mniewoehner.de>
Signed-off-by: Allan Jude <allan@klarasystems.com>
Signed-off-by: Allan Jude <allanjude@freebsd.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Sebastian Gottschall <s.gottschall@dd-wrt.com>
Signed-off-by: Kjeld Schouten-Lebbing <kjeld@schouten-lebbing.nl>
Signed-off-by: Michael Niewöhner <foss@mniewoehner.de>
Closes #6247
Closes #9024
Closes #10277
Closes #10278

1 files changed, 31 insertions, 5 deletions

diff --git a/module/zfs/zfs_ioctl.c b/module/zfs/zfs_ioctl.c
index 463704c14e5a..7f623bb046ea 100644
--- a/module/zfs/zfs_ioctl.c
+++ b/module/zfs/zfs_ioctl.c
@@ -38,6 +38,8 @@
  * Copyright (c) 2017 Open-E, Inc. All Rights Reserved.
  * Copyright (c) 2019 Datto Inc.
  * Copyright (c) 2019, 2020 by Christian Schwarz. All rights reserved.
+ * Copyright (c) 2019, Klara Inc.
+ * Copyright (c) 2019, Allan Jude
  */
 
 /*
@@ -2464,6 +2466,15 @@ zfs_prop_set_special(const char *dsname, zprop_source_t source,
 	case ZFS_PROP_REFRESERVATION:
 		err = dsl_dataset_set_refreservation(dsname, source, intval);
 		break;
+	case ZFS_PROP_COMPRESSION:
+		err = dsl_dataset_set_compression(dsname, source, intval);
+		/*
+		 * Set err to -1 to force the zfs_set_prop_nvlist code down the
+		 * default path to set the value in the nvlist.
+		 */
+		if (err == 0)
+			err = -1;
+		break;
 	case ZFS_PROP_VOLSIZE:
 		err = zvol_set_volsize(dsname, intval);
 		break;
@@ -4355,7 +4366,7 @@ zfs_check_settable(const char *dsname, nvpair_t *pair, cred_t *cr)
 	const char *propname = nvpair_name(pair);
 	boolean_t issnap = (strchr(dsname, '@') != NULL);
 	zfs_prop_t prop = zfs_name_to_prop(propname);
-	uint64_t intval;
+	uint64_t intval, compval;
 	int err;
 
 	if (prop == ZPROP_INVAL) {
@@ -4437,19 +4448,20 @@ zfs_check_settable(const char *dsname, nvpair_t *pair, cred_t *cr)
 		 * we'll catch them later.
 		 */
 		if (nvpair_value_uint64(pair, &intval) == 0) {
-			if (intval >= ZIO_COMPRESS_GZIP_1 &&
-			    intval <= ZIO_COMPRESS_GZIP_9 &&
+			compval = ZIO_COMPRESS_ALGO(intval);
+			if (compval >= ZIO_COMPRESS_GZIP_1 &&
+			    compval <= ZIO_COMPRESS_GZIP_9 &&
 			    zfs_earlier_version(dsname,
 			    SPA_VERSION_GZIP_COMPRESSION)) {
 				return (SET_ERROR(ENOTSUP));
 			}
 
-			if (intval == ZIO_COMPRESS_ZLE &&
+			if (compval == ZIO_COMPRESS_ZLE &&
 			    zfs_earlier_version(dsname,
 			    SPA_VERSION_ZLE_COMPRESSION))
 				return (SET_ERROR(ENOTSUP));
 
-			if (intval == ZIO_COMPRESS_LZ4) {
+			if (compval == ZIO_COMPRESS_LZ4) {
 				spa_t *spa;
 
 				if ((err = spa_open(dsname, &spa, FTAG)) != 0)
@@ -4462,6 +4474,20 @@ zfs_check_settable(const char *dsname, nvpair_t *pair, cred_t *cr)
 				}
 				spa_close(spa, FTAG);
 			}
+
+			if (compval == ZIO_COMPRESS_ZSTD) {
+				spa_t *spa;
+
+				if ((err = spa_open(dsname, &spa, FTAG)) != 0)
+					return (err);
+
+				if (!spa_feature_is_enabled(spa,
+				    SPA_FEATURE_ZSTD_COMPRESS)) {
+					spa_close(spa, FTAG);
+					return (SET_ERROR(ENOTSUP));
+				}
+				spa_close(spa, FTAG);
+			}
 		}
 		break;