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, 11 insertions, 0 deletions

diff --git a/include/sys/dsl_dataset.h b/include/sys/dsl_dataset.h
index edfc5509e..1985ce824 100644
--- a/include/sys/dsl_dataset.h
+++ b/include/sys/dsl_dataset.h
@@ -84,6 +84,13 @@ struct dsl_pool;
 #define	DS_FIELD_BOOKMARK_NAMES "com.delphix:bookmarks"
 
 /*
+ * This field is present (with value=0) if this dataset may contain large
+ * blocks (>128KB).  If it is present, then this dataset
+ * is counted in the refcount of the SPA_FEATURE_LARGE_BLOCKS feature.
+ */
+#define	DS_FIELD_LARGE_BLOCKS "org.open-zfs:large_blocks"
+
+/*
  * DS_FLAG_CI_DATASET is set if the dataset contains a file system whose
  * name lookups should be performed case-insensitively.
  */
@@ -138,6 +145,8 @@ typedef struct dsl_dataset {
 	/* only used in syncing context, only valid for non-snapshots: */
 	struct dsl_dataset *ds_prev;
 	uint64_t ds_bookmarks;  /* DMU_OTN_ZAP_METADATA */
+	boolean_t ds_large_blocks;
+	boolean_t ds_need_large_blocks;
 
 	/* has internal locking: */
 	dsl_deadlist_t ds_deadlist;
@@ -252,6 +261,8 @@ int dsl_dataset_space_written(dsl_dataset_t *oldsnap, dsl_dataset_t *new,
 int dsl_dataset_space_wouldfree(dsl_dataset_t *firstsnap, dsl_dataset_t *last,
     uint64_t *usedp, uint64_t *compp, uint64_t *uncompp);
 boolean_t dsl_dataset_is_dirty(dsl_dataset_t *ds);
+int dsl_dataset_activate_large_blocks(const char *dsname);
+void dsl_dataset_activate_large_blocks_sync_impl(uint64_t dsobj, dmu_tx_t *tx);
 
 int dsl_dsobj_to_dsname(char *pname, uint64_t obj, char *buf);