Illumos 5027 - zfs large block support

5027 zfs large block support
Reviewed by: Alek Pinchuk <[email protected]>
Reviewed by: George Wilson <[email protected]>
Reviewed by: Josef 'Jeff' Sipek <[email protected]>
Reviewed by: Richard Elling <[email protected]>
Reviewed by: Saso Kiselkov <[email protected]>
Reviewed by: Brian Behlendorf <[email protected]>
Approved by: Dan McDonald <[email protected]>

References:
  https://www.illumos.org/issues/5027
  https://github.com/illumos/illumos-gate/commit/b515258

Porting Notes:

* Included in this patch is a tiny ISP2() cleanup in zio_init() from
Illumos 5255.

* Unlike the upstream Illumos commit this patch does not impose an
arbitrary 128K block size limit on volumes.  Volumes, like filesystems,
are limited by the zfs_max_recordsize=1M module option.

* By default the maximum record size is limited to 1M by the module
option zfs_max_recordsize.  This value may be safely increased up to
16M which is the largest block size supported by the on-disk format.
At the moment, 1M blocks clearly offer a significant performance
improvement but the benefits of going beyond this for the majority
of workloads are less clear.

* The illumos version of this patch increased DMU_MAX_ACCESS to 32M.
This was determined not to be large enough when using 16M blocks
because the zfs_make_xattrdir() function will fail (EFBIG) when
assigning a TX.  This was immediately observed under Linux because
all newly created files must have a security xattr created and
that was failing.  Therefore, we've set DMU_MAX_ACCESS to 64M.

* On 32-bit platforms a hard limit of 1M is set for blocks due
to the limited virtual address space.  We should be able to relax
this one the ABD patches are merged.

Ported-by: Brian Behlendorf <[email protected]>
Closes #354

1 files changed, 3 insertions, 2 deletions

diff --git a/module/zfs/bpobj.c b/module/zfs/bpobj.c
index 25767e83f..ebfdc2e7a 100644
--- a/module/zfs/bpobj.c
+++ b/module/zfs/bpobj.c
@@ -43,7 +43,7 @@ bpobj_alloc_empty(objset_t *os, int blocksize, dmu_tx_t *tx)
 		if (!spa_feature_is_active(spa, SPA_FEATURE_EMPTY_BPOBJ)) {
 			ASSERT0(dp->dp_empty_bpobj);
 			dp->dp_empty_bpobj =
-			    bpobj_alloc(os, SPA_MAXBLOCKSIZE, tx);
+			    bpobj_alloc(os, SPA_OLD_MAXBLOCKSIZE, tx);
 			VERIFY(zap_add(os,
 			    DMU_POOL_DIRECTORY_OBJECT,
 			    DMU_POOL_EMPTY_BPOBJ, sizeof (uint64_t), 1,
@@ -399,7 +399,8 @@ bpobj_enqueue_subobj(bpobj_t *bpo, uint64_t subobj, dmu_tx_t *tx)
 	dmu_buf_will_dirty(bpo->bpo_dbuf, tx);
 	if (bpo->bpo_phys->bpo_subobjs == 0) {
 		bpo->bpo_phys->bpo_subobjs = dmu_object_alloc(bpo->bpo_os,
-		    DMU_OT_BPOBJ_SUBOBJ, SPA_MAXBLOCKSIZE, DMU_OT_NONE, 0, tx);
+		    DMU_OT_BPOBJ_SUBOBJ, SPA_OLD_MAXBLOCKSIZE,
+		    DMU_OT_NONE, 0, tx);
 	}
 
 	ASSERT0(dmu_object_info(bpo->bpo_os, bpo->bpo_phys->bpo_subobjs, &doi));