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, 22 insertions, 4 deletions

diff --git a/module/zfs/spa.c b/module/zfs/spa.c
index 3312c301c..2a9ef9ce5 100644
--- a/module/zfs/spa.c
+++ b/module/zfs/spa.c
@@ -266,6 +266,14 @@ spa_prop_get_config(spa_t *spa, nvlist_t **nvp)
 		spa_prop_add_list(*nvp, ZPOOL_PROP_ALTROOT, spa->spa_root,
 		    0, ZPROP_SRC_LOCAL);
 
+	if (spa_feature_is_enabled(spa, SPA_FEATURE_LARGE_BLOCKS)) {
+		spa_prop_add_list(*nvp, ZPOOL_PROP_MAXBLOCKSIZE, NULL,
+		    MIN(zfs_max_recordsize, SPA_MAXBLOCKSIZE), ZPROP_SRC_NONE);
+	} else {
+		spa_prop_add_list(*nvp, ZPOOL_PROP_MAXBLOCKSIZE, NULL,
+		    SPA_OLD_MAXBLOCKSIZE, ZPROP_SRC_NONE);
+	}
+
 	if ((dp = list_head(&spa->spa_config_list)) != NULL) {
 		if (dp->scd_path == NULL) {
 			spa_prop_add_list(*nvp, ZPOOL_PROP_CACHEFILE,
@@ -482,7 +490,7 @@ spa_prop_validate(spa_t *spa, nvlist_t *props)
 
 			if (!error) {
 				objset_t *os;
-				uint64_t compress;
+				uint64_t propval;
 
 				if (strval == NULL || strval[0] == '\0') {
 					objnum = zpool_prop_default_numeric(
@@ -494,15 +502,25 @@ spa_prop_validate(spa_t *spa, nvlist_t *props)
 				if (error)
 					break;
 
-				/* Must be ZPL and not gzip compressed. */
+				/*
+				 * Must be ZPL, and its property settings
+				 * must be supported by GRUB (compression
+				 * is not gzip, and large blocks are not used).
+				 */
 
 				if (dmu_objset_type(os) != DMU_OST_ZFS) {
 					error = SET_ERROR(ENOTSUP);
 				} else if ((error =
 				    dsl_prop_get_int_ds(dmu_objset_ds(os),
 				    zfs_prop_to_name(ZFS_PROP_COMPRESSION),
-				    &compress)) == 0 &&
-				    !BOOTFS_COMPRESS_VALID(compress)) {
+				    &propval)) == 0 &&
+				    !BOOTFS_COMPRESS_VALID(propval)) {
+					error = SET_ERROR(ENOTSUP);
+				} else if ((error =
+				    dsl_prop_get_int_ds(dmu_objset_ds(os),
+				    zfs_prop_to_name(ZFS_PROP_RECORDSIZE),
+				    &propval)) == 0 &&
+				    propval > SPA_OLD_MAXBLOCKSIZE) {
 					error = SET_ERROR(ENOTSUP);
 				} else {
 					objnum = dmu_objset_id(os);