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Raw receives must compress metadnode blocks

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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
This commit is contained in:
Tom Caputi 2018-02-21 15:28:52 -05:00 committed by Brian Behlendorf
parent 5121c4fb0c
commit b1d217338a
7 changed files with 24 additions and 41 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
include/sys/dmu.h
View File

@ -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

11
man/man5/zfs-module-parameters.5
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@ -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

3
module/zfs/arc.c
View File

@ -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 */

3
module/zfs/dbuf.c
View File

@ -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);
}
}

9
module/zfs/dmu.c
View File

@ -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);
}
/*
* 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");

14
module/zfs/zio.c
View File

@ -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);
}
/*

11
tests/zfs-tests/tests/functional/rsend/send_encrypted_files.ksh
View File

@ -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