Destroy ARC buffer in case of fill error

In case of error dmu_buf_fill_done() returns the buffer back into
DB_UNCACHED state.  Since during transition from DB_UNCACHED into
DB_FILL state dbuf_noread() allocates an ARC buffer, we must free
it here, otherwise it will be leaked.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Jorgen Lundman <lundman@lundman.net>
Signed-off-by: Alexander Motin <mav@FreeBSD.org>
Sponsored by: iXsystems, Inc.
Closes #15665
Closes #15802
Closes #16216

module/zfs/dbuf.c

@@ -2853,6 +2853,7 @@ dmu_buf_fill_done(dmu_buf_t *dbuf, dmu_tx_t *tx, boolean_t failed)
 			failed = B_FALSE;
 		} else if (failed) {
 			VERIFY(!dbuf_undirty(db, tx));
+			arc_buf_destroy(db->db_buf, db);
 			db->db_buf = NULL;
 			dbuf_clear_data(db);
 			DTRACE_SET_STATE(db, "fill failed");