LU-14949 llite: Always do lookup on ENOENT in open

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

diff --git a/lustre/llite/file.c b/lustre/llite/file.c
index 934be16..0c08757 100644 (file)
--- a/lustre/llite/file.c
+++ b/lustre/llite/file.c
@@ -636,6 +636,8 @@ retry:
        op_data->op_data = lmm;
        op_data->op_data_size = lmmsize;
 
+       OBD_FAIL_TIMEOUT(OBD_FAIL_LLITE_OPEN_DELAY, cfs_fail_val);
+
        rc = md_intent_lock(sbi->ll_md_exp, op_data, itp, &req,
                            &ll_md_blocking_ast, 0);
        kfree(name);
@@ -687,14 +689,20 @@ out:
        ptlrpc_req_finished(req);
        ll_intent_drop_lock(itp);
 
-       /* We did open by fid, but by the time we got to the server,
-        * the object disappeared. If this is a create, we cannot really
-        * tell the userspace that the file it was trying to create
-        * does not exist. Instead let's return -ESTALE, and the VFS will
-        * retry the create with LOOKUP_REVAL that we are going to catch
-        * in ll_revalidate_dentry() and use lookup then.
+       /* We did open by fid, but by the time we got to the server, the object
+        * disappeared.  This is possible if the object was unlinked, but it's
+        * also possible if the object was unlinked by a rename.  In the case
+        * of an object renamed over our existing one, we can't fail this open.
+        * O_CREAT also goes through this path if we had an existing dentry,
+        * and it's obviously wrong to return ENOENT for O_CREAT.
+        *
+        * Instead let's return -ESTALE, and the VFS will retry the open with
+        * LOOKUP_REVAL, which we catch in ll_revalidate_dentry and fail to
+        * revalidate, causing a lookup.  This causes extra lookups in the case
+        * where we had a dentry in cache but the file is being unlinked and we
+        * lose the race with unlink, but this should be very rare.
         */
-       if (rc == -ENOENT && itp->it_op & IT_CREAT)
+       if (rc == -ENOENT)
                rc = -ESTALE;
 
        RETURN(rc);