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, 1 insertions, 1 deletions

diff --git a/include/sys/zfs_sa.h b/include/sys/zfs_sa.h
index 735d4b32a..06c4d589a 100644
--- a/include/sys/zfs_sa.h
+++ b/include/sys/zfs_sa.h
@@ -129,7 +129,7 @@ typedef struct znode_phys {
 #ifdef _KERNEL
 
 #define	DXATTR_MAX_ENTRY_SIZE	(32768)
-#define	DXATTR_MAX_SA_SIZE	(SPA_MAXBLOCKSIZE >> 1)
+#define	DXATTR_MAX_SA_SIZE	(SPA_OLD_MAXBLOCKSIZE >> 1)
 
 int zfs_sa_readlink(struct znode *, uio_t *);
 void zfs_sa_symlink(struct znode *, char *link, int len, dmu_tx_t *);