[PATCH 1/2] fs: reorganize path_openat()

[Stas Sergeev]

This patch moves the call to alloc_empty_file() below the call to
path_init(). That changes is needed for the next patch, which adds
a cred override for alloc_empty_file(). The needed cred info is only
available after the call to path_init().

No functional changes are intended by that patch.

Signed-off-by: Stas Sergeev <stsp2@xxxxxxxxx>

CC: Eric Biederman <ebiederm@xxxxxxxxxxxx>
CC: Alexander Viro <viro@xxxxxxxxxxxxxxxxxx>
CC: Christian Brauner <brauner@xxxxxxxxxx>
CC: Jan Kara <jack@xxxxxxx>
CC: Andy Lutomirski <luto@xxxxxxxxxx>
CC: linux-fsdevel@xxxxxxxxxxxxxxx
CC: linux-kernel@xxxxxxxxxxxxxxx
---
 fs/namei.c | 26 +++++++++++++++++---------
 1 file changed, 17 insertions(+), 9 deletions(-)

diff --git a/fs/namei.c b/fs/namei.c
index c5b2a25be7d0..2fde2c320ae9 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -3782,22 +3782,30 @@ static struct file *path_openat(struct nameidata *nd,
 	struct file *file;
 	int error;
 
-	file = alloc_empty_file(op->open_flag, current_cred());
-	if (IS_ERR(file))
-		return file;
-
-	if (unlikely(file->f_flags & __O_TMPFILE)) {
+	if (unlikely(op->open_flag & __O_TMPFILE)) {
+		file = alloc_empty_file(op->open_flag, current_cred());
+		if (IS_ERR(file))
+			return file;
 		error = do_tmpfile(nd, flags, op, file);
-	} else if (unlikely(file->f_flags & O_PATH)) {
+	} else if (unlikely(op->open_flag & O_PATH)) {
+		file = alloc_empty_file(op->open_flag, current_cred());
+		if (IS_ERR(file))
+			return file;
 		error = do_o_path(nd, flags, file);
 	} else {
 		const char *s = path_init(nd, flags);
-		while (!(error = link_path_walk(s, nd)) &&
-		       (s = open_last_lookups(nd, file, op)) != NULL)
-			;
+		file = alloc_empty_file(op->open_flag, current_cred());
+		error = PTR_ERR_OR_ZERO(file);
+		if (!error) {
+			while (!(error = link_path_walk(s, nd)) &&
+			       (s = open_last_lookups(nd, file, op)) != NULL)
+				;
+		}
 		if (!error)
 			error = do_open(nd, file, op);
 		terminate_walk(nd);
+		if (IS_ERR(file))
+			return file;
 	}
 	if (likely(!error)) {
 		if (likely(file->f_mode & FMODE_OPENED))
-- 
2.44.0