MFV r255257: 4082 zfs receive gets EFBIG from dmu_tx_hold_free()

  illumos change 14172:be36a38bac3d:
  illumos ZFS issues:
    4082 zfs receive gets EFBIG from dmu_tx_hold_free()

Please note that this change is slightly different from r255257, because
it is merged out of order with other (larger) upstream changes.

PR:		kern/182570
Reported by:	Keith White <kwhite@site.uottawa.ca>
Tested by:	Keith White <kwhite@site.uottawa.ca>
Approved by:	re (glebius)
MFC after:	1 week
X-MFC after:	r254753

2 files changed, 11 insertions, 1 deletions

diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu.c b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu.c
index 9e661be..a17eea9 100644
--- a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu.c
+++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu.c
@@ -677,6 +677,16 @@ dmu_free_long_range(objset_t *os, uint64_t object,
 	if (err != 0)
 		return (err);
 	err = dmu_free_long_range_impl(os, dn, offset, length);
+
+	/*
+	 * It is important to zero out the maxblkid when freeing the entire
+	 * file, so that (a) subsequent calls to dmu_free_long_range_impl()
+	 * will take the fast path, and (b) dnode_reallocate() can verify
+	 * that the entire file has been freed.
+	 */
+	if (offset == 0 && length == DMU_OBJECT_END)
+		dn->dn_maxblkid = 0;
+
 	dnode_rele(dn, FTAG);
 	return (err);
 }
diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu_tx.c b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu_tx.c
index dddaa0a..0cfd0ad 100644
--- a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu_tx.c
+++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu_tx.c
@@ -616,7 +616,7 @@ dmu_tx_hold_free(dmu_tx_t *tx, uint64_t object, uint64_t off, uint64_t len)
 	 */
 	if (dn->dn_datablkshift == 0) {
 		if (off != 0 || len < dn->dn_datablksz)
-			dmu_tx_count_write(txh, off, len);
+			dmu_tx_count_write(txh, 0, dn->dn_datablksz);
 	} else {
 		/* first block will be modified if it is not aligned */
 		if (!IS_P2ALIGNED(off, 1 << dn->dn_datablkshift))