[PATCH 14/14] namei: clean up do_renameat2 retry logic

[Dmitry Kadashev <dkadashev@gmail.com>]

No functional changes, just move the main logic to a helper function to
make the whole thing 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/
Link: https://lore.kernel.org/io-uring/CAHk-=wjFd0qn6asio=zg7zUTRmSty_TpAEhnwym1Qb=wFgCKzA@mail.gmail.com/
Signed-off-by: Dmitry Kadashev <dkadashev@gmail.com>
---
 fs/namei.c | 34 +++++++++++++++++++++-------------
 1 file changed, 21 insertions(+), 13 deletions(-)

diff --git a/fs/namei.c b/fs/namei.c
index a75abff5a9a6..dce0e427b95a 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -4643,8 +4643,9 @@ 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 try_renameat(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;
@@ -4653,16 +4654,15 @@ 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;
-	int error = -EINVAL;
+	unsigned int target_flags = LOOKUP_RENAME_TARGET;
+	int error;
 
-retry:
 	if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE | RENAME_WHITEOUT))
-		goto put_names;
+		return -EINVAL;
 
 	if ((flags & (RENAME_NOREPLACE | RENAME_WHITEOUT)) &&
 	    (flags & RENAME_EXCHANGE))
-		goto put_names;
+		return -EINVAL;
 
 	if (flags & RENAME_EXCHANGE)
 		target_flags = 0;
@@ -4670,7 +4670,7 @@ int do_renameat2(int olddfd, struct filename *from, int newdfd,
 	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);
@@ -4771,11 +4771,19 @@ int do_renameat2(int olddfd, struct filename *from, int newdfd,
 	path_put(&new_path);
 exit1:
 	path_put(&old_path);
-put_names:
-	if (retry_estale(error, lookup_flags)) {
-		lookup_flags |= LOOKUP_REVAL;
-		goto retry;
-	}
+	return error;
+}
+
+int do_renameat2(int olddfd, struct filename *from, int newdfd,
+		 struct filename *to, unsigned int flags)
+{
+	int error;
+
+	error = try_renameat(olddfd, from, newdfd, to, flags, 0);
+	if (unlikely(retry_estale(error, 0)))
+		error = try_renameat(olddfd, from, newdfd, to, flags,
+				     LOOKUP_REVAL);
+
 	putname(from);
 	putname(to);
 	return error;
-- 
2.30.2