---

yaml
---
r: 310068
b: refs/heads/master
c: 16b1c1c
h: refs/heads/master
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 50ee93afcaa970620d1fb5a9894109a2ab152868
+refs/heads/master: 16b1c1cd71176ab0a76b26818fbf12db9183ed57

trunk/fs/namei.c

@@ -2202,6 +2202,8 @@ static struct file *do_last(struct nameidata *nd, struct path *path,
 	struct file *filp;
 	struct inode *inode;
 	int symlink_ok = 0;
+	struct path save_parent = { .dentry = NULL, .mnt = NULL };
+	bool retried = false;
 	int error;
 
 	nd->flags &= ~LOOKUP_PARENT;
@@ -2267,6 +2269,7 @@ static struct file *do_last(struct nameidata *nd, struct path *path,
 	if (nd->last.name[nd->last.len])
 		goto exit;
 
+retry_lookup:
 	mutex_lock(&dir->d_inode->i_mutex);
 
 	dentry = lookup_hash(nd);
@@ -2349,12 +2352,21 @@ static struct file *do_last(struct nameidata *nd, struct path *path,
 		return NULL;
 	}
 
-	path_to_nameidata(path, nd);
+	if ((nd->flags & LOOKUP_RCU) || nd->path.mnt != path->mnt) {
+		path_to_nameidata(path, nd);
+	} else {
+		save_parent.dentry = nd->path.dentry;
+		save_parent.mnt = mntget(path->mnt);
+		nd->path.dentry = path->dentry;
+
+	}
 	nd->inode = inode;
 	/* Why this, you ask?  _Now_ we might have grown LOOKUP_JUMPED... */
 	error = complete_walk(nd);
-	if (error)
+	if (error) {
+		path_put(&save_parent);
 		return ERR_PTR(error);
+	}
 	error = -EISDIR;
 	if ((open_flag & O_CREAT) && S_ISDIR(nd->inode->i_mode))
 		goto exit;
@@ -2377,6 +2389,20 @@ static struct file *do_last(struct nameidata *nd, struct path *path,
 	if (error)
 		goto exit;
 	filp = nameidata_to_filp(nd);
+	if (filp == ERR_PTR(-EOPENSTALE) && save_parent.dentry && !retried) {
+		BUG_ON(save_parent.dentry != dir);
+		path_put(&nd->path);
+		nd->path = save_parent;
+		nd->inode = dir->d_inode;
+		save_parent.mnt = NULL;
+		save_parent.dentry = NULL;
+		if (want_write) {
+			mnt_drop_write(nd->path.mnt);
+			want_write = 0;
+		}
+		retried = true;
+		goto retry_lookup;
+	}
 	if (!IS_ERR(filp)) {
 		error = ima_file_check(filp, op->acc_mode);
 		if (error) {
@@ -2396,6 +2422,7 @@ static struct file *do_last(struct nameidata *nd, struct path *path,
 out:
 	if (want_write)
 		mnt_drop_write(nd->path.mnt);
+	path_put(&save_parent);
 	terminate_walk(nd);
 	return filp;
 
@@ -2459,6 +2486,12 @@ static struct file *path_openat(int dfd, const char *pathname,
 	if (base)
 		fput(base);
 	release_open_intent(nd);
+	if (filp == ERR_PTR(-EOPENSTALE)) {
+		if (flags & LOOKUP_RCU)
+			filp = ERR_PTR(-ECHILD);
+		else
+			filp = ERR_PTR(-ESTALE);
+	}
 	return filp;
 
 out_filp:

trunk/include/linux/errno.h

@@ -17,6 +17,7 @@
 #define ENOIOCTLCMD	515	/* No ioctl command */
 #define ERESTART_RESTARTBLOCK 516 /* restart by calling sys_restart_syscall */
 #define EPROBE_DEFER	517	/* Driver requests probe retry */
+#define EOPENSTALE	518	/* open found a stale dentry */
 
 /* Defined for the NFSv3 protocol */
 #define EBADHANDLE	521	/* Illegal NFS file handle */