Raw receives must compress metadnode blocks

Currently, the DMU relies on ZIO layer compression to free LO
dnode blocks that no longer have objects in them. However,
raw receives disable all compression, meaning that these blocks
can never be freed. In addition to the obvious space concerns,
this could also cause incremental raw receives to fail to mount
since the MAC of a hole is different from that of a completely
zeroed block.

This patch corrects this issue by adding a special case in
zio_write_compress() which will attempt to compress these blocks
to a hole even if ZIO_FLAG_RAW_ENCRYPT is set. This patch also
removes the zfs_mdcomp_disable tunable, since tuning it could
cause these same issues.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Tom Caputi <tcaputi@datto.com>
Closes #7198

diff --git a/include/sys/dmu.h b/include/sys/dmu.h
index cf9cbaa645e644c92486a74fae2760827bb99318..472a4f2b65752507ec368802e5b81fc7de508d2f 100644 (file)
--- a/include/sys/dmu.h
+++ b/include/sys/dmu.h
@@ -1033,8 +1033,6 @@ int dmu_diff(const char *tosnap_name, const char *fromsnap_name,
 #define        ZFS_CRC64_POLY  0xC96C5795D7870F42ULL   /* ECMA-182, reflected form */
 extern uint64_t zfs_crc64_table[256];
 
-extern int zfs_mdcomp_disable;
-
 #ifdef __cplusplus
 }
 #endif

diff --git a/man/man5/zfs-module-parameters.5 b/man/man5/zfs-module-parameters.5
index 529684742d8034b0a8ce4767f9e4a860bd8e8030..17335ebed92791988f5c29c6e4b7fe8b7a0d94c5 100644 (file)
--- a/man/man5/zfs-module-parameters.5
+++ b/man/man5/zfs-module-parameters.5
@@ -1400,17 +1400,6 @@ regardless of this setting.
 Default value: \fB1,048,576\fR.
 .RE
 
-.sp
-.ne 2
-.na
-\fBzfs_mdcomp_disable\fR (int)
-.ad
-.RS 12n
-Disable meta data compression
-.sp
-Use \fB1\fR for yes and \fB0\fR for no (default).
-.RE
-
 .sp
 .ne 2
 .na

diff --git a/module/zfs/arc.c b/module/zfs/arc.c
index 7aa221b0034630b5b3d0a0b7205052aefaccc81a..a78a029c21d1b3f76a1f6461d3430e0d0fca6ae8 100644 (file)
--- a/module/zfs/arc.c
+++ b/module/zfs/arc.c
@@ -6776,6 +6776,9 @@ arc_write_ready(zio_t *zio)
                buf->b_flags &= ~ARC_BUF_FLAG_ENCRYPTED;
                if (BP_GET_COMPRESS(bp) == ZIO_COMPRESS_OFF)
                        buf->b_flags &= ~ARC_BUF_FLAG_COMPRESSED;
+       } else if (BP_IS_HOLE(bp) && ARC_BUF_ENCRYPTED(buf)) {
+               buf->b_flags &= ~ARC_BUF_FLAG_ENCRYPTED;
+               buf->b_flags &= ~ARC_BUF_FLAG_COMPRESSED;
        }
 
        /* this must be done after the buffer flags are adjusted */

diff --git a/module/zfs/dbuf.c b/module/zfs/dbuf.c
index 51cb0c982f4991e2a852abc1e1c02d8c2eadd9fb..e885a27561360c32b57437c588f28270fabbbd1e 100644 (file)
--- a/module/zfs/dbuf.c
+++ b/module/zfs/dbuf.c
@@ -3465,7 +3465,8 @@ dbuf_check_crypt(dbuf_dirty_record_t *dr)
                 * Writing raw encrypted data requires the db's arc buffer
                 * to be converted to raw by the caller.
                 */
-               ASSERT(arc_is_encrypted(db->db_buf));
+               ASSERT(arc_is_encrypted(db->db_buf) ||
+                   db->db.db_object == DMU_META_DNODE_OBJECT);
        }
 }
 

diff --git a/module/zfs/dmu.c b/module/zfs/dmu.c
index b7c5bba150e3073b90f83209947d0c694547d5e3..e0114e659ced5472d85b4edcbe853e3dcf87bc92 100644 (file)
--- a/module/zfs/dmu.c
+++ b/module/zfs/dmu.c
@@ -2107,8 +2107,6 @@ dmu_object_dirty_raw(objset_t *os, uint64_t object, dmu_tx_t *tx)
        return (err);
 }
 
-int zfs_mdcomp_disable = 0;
-
 /*
  * When the "redundant_metadata" property is set to "most", only indirect
  * blocks of this level and higher will have an additional ditto block.
@@ -2138,16 +2136,12 @@ dmu_write_policy(objset_t *os, dnode_t *dn, int level, int wp, zio_prop_t *zp)
         *       3. all other level 0 blocks
         */
        if (ismd) {
-               if (zfs_mdcomp_disable) {
-                       compress = ZIO_COMPRESS_EMPTY;
-               } else {
-                       /*
-                        * XXX -- we should design a compression algorithm
-                        * that specializes in arrays of bps.
-                        */
-                       compress = zio_compress_select(os->os_spa,
-                           ZIO_COMPRESS_ON, ZIO_COMPRESS_ON);
-               }
+               /*
+                * XXX -- we should design a compression algorithm
+                * that specializes in arrays of bps.
+                */
+               compress = zio_compress_select(os->os_spa,
+                   ZIO_COMPRESS_ON, ZIO_COMPRESS_ON);
 
                /*
                 * Metadata always gets checksummed.  If the data
@@ -2523,9 +2517,6 @@ EXPORT_SYMBOL(dmu_buf_hold);
 EXPORT_SYMBOL(dmu_ot);
 
 /* BEGIN CSTYLED */
-module_param(zfs_mdcomp_disable, int, 0644);
-MODULE_PARM_DESC(zfs_mdcomp_disable, "Disable meta data compression");
-
 module_param(zfs_nopwrite_enabled, int, 0644);
 MODULE_PARM_DESC(zfs_nopwrite_enabled, "Enable NOP writes");
 

diff --git a/module/zfs/zio.c b/module/zfs/zio.c
index 9458f39248031c33326ee7fc4f0c4be17ceaff58..7544cf4e3a3de6d5ec2a27fdf68ab24ae1633099 100644 (file)
--- a/module/zfs/zio.c
+++ b/module/zfs/zio.c
@@ -1532,9 +1532,21 @@ zio_write_compress(zio_t *zio)
                *bp = zio->io_bp_orig;
                zio->io_pipeline = zio->io_orig_pipeline;
 
+       } else if ((zio->io_flags & ZIO_FLAG_RAW_ENCRYPT) != 0 &&
+           zp->zp_type == DMU_OT_DNODE) {
+               /*
+                * The DMU actually relies on the zio layer's compression
+                * to free metadnode blocks that have had all contained
+                * dnodes freed. As a result, even when doing a raw
+                * receive, we must check whether the block can be compressed
+                * to a hole.
+                */
+               psize = zio_compress_data(ZIO_COMPRESS_EMPTY,
+                   zio->io_abd, NULL, lsize);
+               if (psize == 0)
+                       compress = ZIO_COMPRESS_OFF;
        } else {
                ASSERT3U(psize, !=, 0);
-
        }
 
        /*

diff --git a/tests/zfs-tests/tests/functional/rsend/send_encrypted_files.ksh b/tests/zfs-tests/tests/functional/rsend/send_encrypted_files.ksh
index 20f3788d561a9716f9901449053c16e77eb16edd..998c2afc3d2cd2dc0b618d2e0889492d5994db35 100755 (executable)
--- a/tests/zfs-tests/tests/functional/rsend/send_encrypted_files.ksh
+++ b/tests/zfs-tests/tests/functional/rsend/send_encrypted_files.ksh
@@ -39,11 +39,6 @@
 
 verify_runnable "both"
 
-function set_metadata_compression_disabled # <0|1>
-{
-       echo $1 > /sys/module/zfs/parameters/zfs_mdcomp_disable
-}
-
 function cleanup
 {
        datasetexists $TESTPOOL/$TESTFS2 && \
@@ -73,12 +68,6 @@ log_must mkfile 32M /$TESTPOOL/$TESTFS2/truncated
 log_must truncate -s 4M /$TESTPOOL/$TESTFS2/truncated
 sync
 
-log_must set_metadata_compression_disabled 1
-log_must dd if=/dev/urandom of=/$TESTPOOL/$TESTFS2/no_mdcomp \
-       count=1 bs=512 seek=10G >/dev/null 2>&1
-sync
-log_must set_metadata_compression_disabled 0
-
 log_must mkdir -p /$TESTPOOL/$TESTFS2/dir
 for i in {1..1000}; do
        log_must mkfile 512 /$TESTPOOL/$TESTFS2/dir/file-$i