s3: smbd: Allow a SHUTDOWN_CLOSE on a file with outstanding aio if there are no client connections alive.

The process is exiting now so pthreads will never complete to cause
problems.

Remove the knownfail.d/aio_outstanding entry.

Followup-bugfix for:

BUG: https://bugzilla.samba.org/show_bug.cgi?id=14301

Signed-off-by: Jeremy Allison <jra@samba.org>
Reviewed-by: Volker Lendecke <vl@samba.org>

Autobuild-User(master): Jeremy Allison <jra@samba.org>
Autobuild-Date(master): Wed Jun 24 20:14:15 UTC 2020 on sn-devel-184

(cherry picked from commit 205653732064ecf76d3198451240af468806ec14)

2 files changed, 26 insertions, 2 deletions

diff --git a/selftest/knownfail.d/aio_outstanding b/selftest/knownfail.d/aio_outstanding
deleted file mode 100644
index 6426f760cb1..00000000000
--- a/selftest/knownfail.d/aio_outstanding
+++ /dev/null
@@ -1,2 +0,0 @@
-samba3.blackbox.aio-outstanding
-
diff --git a/source3/smbd/close.c b/source3/smbd/close.c
index d5af62a277c..1a6e33b4403 100644
--- a/source3/smbd/close.c
+++ b/source3/smbd/close.c
@@ -639,12 +639,38 @@ static NTSTATUS ntstatus_keeperror(NTSTATUS s1, NTSTATUS s2)
 static void assert_no_pending_aio(struct files_struct *fsp,
 				  enum file_close_type close_type)
 {
+	struct smbXsrv_client *client = global_smbXsrv_client;
+	size_t num_connections_alive;
 	unsigned num_requests = fsp->num_aio_requests;
 
 	if (num_requests == 0) {
 		return;
 	}
 
+	num_connections_alive = smbXsrv_client_valid_connections(client);
+
+	if (close_type == SHUTDOWN_CLOSE && num_connections_alive == 0) {
+		/*
+		 * fsp->aio_requests and the contents (fsp->aio_requests[x])
+		 * are both independently owned by fsp and are not in a
+		 * talloc heirarchy. This allows the fsp->aio_requests array to
+		 * be reallocated independently of the array contents so it can
+		 * grow on demand.
+		 *
+		 * This means we must ensure order of deallocation
+		 * on a SHUTDOWN_CLOSE by deallocating the fsp->aio_requests[x]
+		 * contents first, as their destructors access the
+		 * fsp->aio_request array. If we don't deallocate them
+		 * first, when fsp is deallocated fsp->aio_requests
+		 * could have been deallocated *before* its contents
+		 * fsp->aio_requests[x], causing a crash.
+		 */
+		while (fsp->num_aio_requests != 0) {
+			TALLOC_FREE(fsp->aio_requests[0]);
+		}
+		return;
+	}
+
 	DBG_ERR("fsp->num_aio_requests=%u\n", num_requests);
 	smb_panic("can not close with outstanding aio requests");
 	return;