From 2e7b7657cdb9ad02c0e0fcf6c8b2bb1c58d1273a Mon Sep 17 00:00:00 2001
From: Matthew Ahrens <mahrens@delphix.com>
Date: Sat, 1 Feb 2014 02:52:11 +1100
Subject: [PATCH] 4188 assertion failed in dmu_tx_hold_free(): dn_datablkshift
 != 0

Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed by: Christopher Siden <christopher.siden@delphix.com>
Approved by: Garrett D'Amore <garrett@damore.org>

Refences:
  https://www.illumos.org/issues/4188
  illumos/illumos-gate@bb411a08b05466bfe0c7095b6373bbc1587e259a

Ported-by: Chris Dunlop <chris@onthe.net.au>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #2091
---
 module/zfs/dmu_tx.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/module/zfs/dmu_tx.c b/module/zfs/dmu_tx.c
index 47cb86b08..3e04793cf 100644
--- a/module/zfs/dmu_tx.c
+++ b/module/zfs/dmu_tx.c
@@ -656,9 +656,16 @@ dmu_tx_hold_free(dmu_tx_t *tx, uint64_t object, uint64_t off, uint64_t len)
 		uint64_t end = (off + len) >> shift;
 		uint64_t i;
 
-		ASSERT(dn->dn_datablkshift != 0);
 		ASSERT(dn->dn_indblkshift != 0);
 
+		/*
+		 * dnode_reallocate() can result in an object with indirect
+		 * blocks having an odd data block size.  In this case,
+		 * just check the single block.
+		 */
+		if (dn->dn_datablkshift == 0)
+			start = end = 0;
+
 		zio = zio_root(tx->tx_pool->dp_spa,
 		    NULL, NULL, ZIO_FLAG_CANFAIL);
 		for (i = start; i <= end; i++) {