LU-4198 clio: turn on lockless for some kind of IO

[fs/lustre-release.git] / lustre / llite / rw.c

diff --git a/lustre/llite/rw.c b/lustre/llite/rw.c
index 2979d17..9b2ecdd 100644 (file)
--- a/lustre/llite/rw.c
+++ b/lustre/llite/rw.c
@@ -1569,6 +1569,20 @@ int ll_readpage(struct file *file, struct page *vmpage)
                RETURN(result);
        }
 
+       /**
+        * 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 (file->f_flags & O_DIRECT &&
+           lcc && lcc->lcc_type == LCC_RW &&
+           !io->ci_ignore_lockless) {
+               unlock_page(vmpage);
+               io->ci_ignore_lockless = 1;
+               io->ci_need_restart = 1;
+               RETURN(-ENOLCK);
+       }
+
        LASSERT(io->ci_state == CIS_IO_GOING);
        page = cl_page_find(env, clob, vmpage->index, vmpage, CPT_CACHEABLE);
        if (!IS_ERR(page)) {