[PATCH 05/14] namei: prepare do_mkdirat for refactoring

[Dmitry Kadashev <dkadashev@gmail.com>]

This is just a preparation for the move of the main mkdirat logic to a
separate function to make the logic easier to follow.  This change
contains the flow changes so that the actual change to move the main
logic to a separate function does no change the flow at all.

Just like the similar patches for rmdir and unlink a few commits before,
there two changes here:

1. Previously on filename_create() error the function used to exit
immediately, and now it will check the return code to see if ESTALE
retry is appropriate. The filename_create() does its own retries on
ESTALE (at least via filename_parentat() used inside), but this extra
check should be completely fine.

2. The retry_estale() check is wrapped in unlikely(). Some other places
already have that and overall it seems to make sense

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-=wijsw1QSsQHFu_6dEoZEr_zvT7++WJWohcuEkLqqXBGrQ@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 | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/fs/namei.c b/fs/namei.c
index 703cce40d597..54dbd1e38298 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -3861,7 +3861,7 @@ int do_mkdirat(int dfd, struct filename *name, umode_t mode)
 	dentry = __filename_create(dfd, name, &path, lookup_flags);
 	error = PTR_ERR(dentry);
 	if (IS_ERR(dentry))
-		goto out_putname;
+		goto out;
 
 	if (!IS_POSIXACL(path.dentry->d_inode))
 		mode &= ~current_umask();
@@ -3873,11 +3873,11 @@ int do_mkdirat(int dfd, struct filename *name, umode_t mode)
 				  mode);
 	}
 	done_path_create(&path, dentry);
-	if (retry_estale(error, lookup_flags)) {
+out:
+	if (unlikely(retry_estale(error, lookup_flags))) {
 		lookup_flags |= LOOKUP_REVAL;
 		goto retry;
 	}
-out_putname:
 	putname(name);
 	return error;
 }
-- 
2.30.2