[PATCH 7/7] namei: clean up do_renameat retry logic

[Dmitry Kadashev <dkadashev@gmail.com>]

Moving the main logic to a helper function makes the whole thing much
easier to follow.

Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christian Brauner <christian.brauner@ubuntu.com>
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/io-uring/CAHk-=wiG+sN+2zSoAOggKCGue2kOJvw3rQySvQXsZstRQFTN+g@mail.gmail.com/
Signed-off-by: Dmitry Kadashev <dkadashev@gmail.com>
---
 fs/namei.c | 36 ++++++++++++++++++++----------------
 1 file changed, 20 insertions(+), 16 deletions(-)

diff --git a/fs/namei.c b/fs/namei.c
index 5e4fa8b65a8d..023ee19aa5ed 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -4658,8 +4658,9 @@ int vfs_rename(struct renamedata *rd)
 }
 EXPORT_SYMBOL(vfs_rename);
 
-int do_renameat2(int olddfd, struct filename *from, int newdfd,
-		 struct filename *to, unsigned int flags)
+static int renameat_helper(int olddfd, struct filename *from, int newdfd,
+			   struct filename *to, unsigned int flags,
+			   unsigned int lookup_flags)
 {
 	struct renamedata rd;
 	struct dentry *old_dentry, *new_dentry;
@@ -4668,25 +4669,23 @@ int do_renameat2(int olddfd, struct filename *from, int newdfd,
 	struct qstr old_last, new_last;
 	int old_type, new_type;
 	struct inode *delegated_inode = NULL;
-	unsigned int lookup_flags = 0, target_flags = LOOKUP_RENAME_TARGET;
-	bool should_retry = false;
+	unsigned int target_flags = LOOKUP_RENAME_TARGET;
 	int error = -EINVAL;
 
 	if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE | RENAME_WHITEOUT))
-		goto put_names;
+		return error;
 
 	if ((flags & (RENAME_NOREPLACE | RENAME_WHITEOUT)) &&
 	    (flags & RENAME_EXCHANGE))
-		goto put_names;
+		return error;
 
 	if (flags & RENAME_EXCHANGE)
 		target_flags = 0;
 
-retry:
 	error = __filename_parentat(olddfd, from, lookup_flags, &old_path,
 					&old_last, &old_type);
 	if (error)
-		goto put_names;
+		return error;
 
 	error = __filename_parentat(newdfd, to, lookup_flags, &new_path, &new_last,
 				&new_type);
@@ -4784,17 +4783,22 @@ int do_renameat2(int olddfd, struct filename *from, int newdfd,
 	}
 	mnt_drop_write(old_path.mnt);
 exit2:
-	if (retry_estale(error, lookup_flags))
-		should_retry = true;
 	path_put(&new_path);
 exit1:
 	path_put(&old_path);
-	if (should_retry) {
-		should_retry = false;
-		lookup_flags |= LOOKUP_REVAL;
-		goto retry;
-	}
-put_names:
+	return error;
+}
+
+int do_renameat2(int olddfd, struct filename *from, int newdfd,
+		 struct filename *to, unsigned int flags)
+{
+	int error;
+
+	error = renameat_helper(olddfd, from, newdfd, to, flags, 0);
+	if (retry_estale(error, 0))
+		error = renameat_helper(olddfd, from, newdfd, to, flags,
+					LOOKUP_REVAL);
+
 	putname(from);
 	putname(to);
 	return error;
-- 
2.30.2