[PATCH v7 32/49] vfs: fix renameat to retry on ESTALE errors

[Jeff Layton]

...as always, rename is the messiest of the bunch. We have to track
whether to retry or not via a separate flag since the error handling
is already quite complex.

Signed-off-by: Jeff Layton <jlayton at redhat.com>
---
 fs/namei.c | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/fs/namei.c b/fs/namei.c
index f311ed1..dfdcd47 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -3851,15 +3851,18 @@ SYSCALL_DEFINE4(renameat, int, olddfd, const char __user *, oldname,
 	struct nameidata oldnd, newnd;
 	struct getname_info *from;
 	struct getname_info *to;
+	unsigned int try = 0;
+	bool should_retry = false;
 	int error;
 
-	from = user_path_parent(olddfd, oldname, &oldnd, 0);
+retry:
+	from = user_path_parent(olddfd, oldname, &oldnd, try);
 	if (IS_ERR(from)) {
 		error = PTR_ERR(from);
 		goto exit;
 	}
 
-	to = user_path_parent(newdfd, newname, &newnd, 0);
+	to = user_path_parent(newdfd, newname, &newnd, try);
 	if (IS_ERR(to)) {
 		error = PTR_ERR(to);
 		goto exit1;
@@ -3931,11 +3934,17 @@ exit3:
 	unlock_rename(new_dir, old_dir);
 	mnt_drop_write(oldnd.path.mnt);
 exit2:
+	if (retry_estale(error, try++))
+		should_retry = true;
 	path_put(&newnd.path);
 	putname(to);
 exit1:
 	path_put(&oldnd.path);
 	putname(from);
+	if (should_retry) {
+		should_retry = false;
+		goto retry;
+	}
 exit:
 	return error;
 }
-- 
1.7.11.4