X-Git-Url: https://git.whamcloud.com/?p=fs%2Flustre-release.git;a=blobdiff_plain;f=lustre%2Fllite%2Frw26.c;h=ab6bec998f03aaa03fcd18bb9c57fb45e83164c8;hp=6f2bb6c0ffb71635256f64640901d1d9e767a905;hb=6bce536725efd166d2772f13fe954f271f9c53b8;hpb=361e9eaef13c0f472ad45388d3e147dabc32b737

diff --git a/lustre/llite/rw26.c b/lustre/llite/rw26.c
index 6f2bb6c..ab6bec9 100644
--- a/lustre/llite/rw26.c
+++ b/lustre/llite/rw26.c
@@ -672,14 +672,25 @@ static int ll_write_begin(struct file *file, struct address_space *mapping,
 	env = lcc->lcc_env;
 	io  = lcc->lcc_io;
 
-	if (file->f_flags & O_DIRECT && io->ci_designated_mirror > 0) {
+	if (file->f_flags & O_DIRECT) {
 		/* direct IO failed because it couldn't clean up cached pages,
 		 * this causes a problem for mirror write because the cached
 		 * page may belong to another mirror, which will result in
 		 * problem submitting the I/O. */
-		GOTO(out, result = -EBUSY);
-	}
+		if (io->ci_designated_mirror > 0)
+			GOTO(out, result = -EBUSY);
 
+		/**
+		 * Direct read can fall back to buffered read, but DIO is done
+		 * with lockless i/o, and buffered requires LDLM locking, so
+		 * in this case we must restart without lockless.
+		 */
+		if (!io->ci_ignore_lockless) {
+			io->ci_ignore_lockless = 1;
+			io->ci_need_restart = 1;
+			GOTO(out, result = -ENOLCK);
+		}
+	}
 again:
 	/* To avoid deadlock, try to lock page first. */
 	vmpage = grab_cache_page_nowait(mapping, index);