Add lz4hc_compress per-dataset feature flag

Require it being enabled for compression=lz4hc* . Activate LZ4HC feature if needed when syncing objset.
openzfs · Apr 30, 2016 · 78fd130 · 78fd130
1 parent d0e8f1f
commit 78fd130
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Showing 5 changed files with 60 additions and 1 deletion.
diff --git a/include/zfeature_common.h b/include/zfeature_common.h
@@ -50,6 +50,7 @@ typedef enum spa_feature {
 	SPA_FEATURE_BOOKMARKS,
 	SPA_FEATURE_FS_SS_LIMIT,
 	SPA_FEATURE_LARGE_BLOCKS,
+	SPA_FEATURE_LZ4HC_COMPRESS,
 	SPA_FEATURES
 } spa_feature_t;
 

diff --git a/man/man5/zpool-features.5 b/man/man5/zpool-features.5
@@ -432,5 +432,34 @@ set larger than 128KB, and will return to being \fBenabled\fR once all
 filesystems that have ever had their recordsize larger than 128KB are destroyed.
 .RE
 
+.sp
+.ne 2
+.na
+\fB\fBlz4hc_compress\fR\fR
+.ad
+.RS 4n
+.TS
+l l .
+GUID	org.zfsonlinux:lz4hc_compress
+READ\-ONLY COMPATIBLE	yes
+DEPENDENCIES	lz4_compress
+.TE
+
+\fBlz4hc\fR is the high-compression variant of \fBlz4\fR. It has
+slower compression, but uses \fBlz4\fR for decompression, so
+decompression is as fast as \fBlz4\fR's.
+
+When the \fBlz4hc_compress\fR feature is set to \fBenabled\fR, the
+administrator can turn on \fBlz4hc\fR compression on any dataset on
+the pool using the \fBzfs\fR(8) command. Doing so will immediately
+activate the \fBlz4hc_compress\fR feature on the underlying
+pool. Booting off of \fBlz4hc\fR-compressed root pools is supported.
+
+This feature becomes \fBactive\fR once a \fBcompression\fR property
+has been set to \fBlz4hc\fR and will return to being \fBenabled\fB
+once all filesystems that have ever had their compression set to
+\fBlz4hc\fR are destroyed.
+.RE
+
 .SH "SEE ALSO"
 \fBzpool\fR(8)
diff --git a/module/zfs/dmu_objset.c b/module/zfs/dmu_objset.c
@@ -1067,6 +1067,12 @@ dmu_objset_write_done(zio_t *zio, arc_buf_t *abuf, void *arg)
 
 		(void) dsl_dataset_block_kill(ds, bp_orig, tx, B_TRUE);
 		dsl_dataset_block_born(ds, bp, tx);
+
+		/* TODO create zio_compress_to_feature */
+		if (os->os_compress >= ZIO_COMPRESS_LZ4HC_1 &&
+		    os->os_compress <= ZIO_COMPRESS_LZ4HC_16)
+			ds->ds_feature_activation_needed[
+			    SPA_FEATURE_LZ4HC_COMPRESS] = B_TRUE;
 	}
 }
 

diff --git a/module/zfs/zfeature_common.c b/module/zfs/zfeature_common.c
@@ -242,4 +242,16 @@ zpool_feature_init(void)
 	    "Support for blocks larger than 128KB.",
 	    ZFEATURE_FLAG_PER_DATASET, large_blocks_deps);
 	}
+
+	{
+	static const spa_feature_t lz4hc_compress_deps[] = {
+		SPA_FEATURE_LZ4_COMPRESS,
+		SPA_FEATURE_NONE
+	};
+	zfeature_register(SPA_FEATURE_LZ4HC_COMPRESS,
+	    "org.zfsonlinux:lz4hc_compress", "lz4hc_compress",
+	    "LZ4HC compression algorithm support.",
+	    ZFEATURE_FLAG_PER_DATASET | ZFEATURE_FLAG_READONLY_COMPAT,
+	    lz4hc_compress_deps);
+	}
 }
diff --git a/module/zfs/zfs_ioctl.c b/module/zfs/zfs_ioctl.c
@@ -3723,11 +3723,22 @@ zfs_check_settable(const char *dsname, nvpair_t *pair, cred_t *cr)
 				if ((err = spa_open(dsname, &spa, FTAG)) != 0)
 					return (err);
 
-				if (!spa_feature_is_enabled(spa,
+				/* TODO create zio_compress_to_feature */
+				if (intval == ZIO_COMPRESS_LZ4 &&
+				    !spa_feature_is_enabled(spa,
 				    SPA_FEATURE_LZ4_COMPRESS)) {
 					spa_close(spa, FTAG);
 					return (SET_ERROR(ENOTSUP));
 				}
+
+				if (intval >= ZIO_COMPRESS_LZ4HC_1 &&
+				    intval <= ZIO_COMPRESS_LZ4HC_16 &&
+				    !spa_feature_is_enabled(spa,
+				    SPA_FEATURE_LZ4HC_COMPRESS)) {
+					spa_close(spa, FTAG);
+					return (SET_ERROR(ENOTSUP));
+				}
+
 				spa_close(spa, FTAG);
 			}