[PATCH 04/10] fhandle: create do_filp_path_open() helper

[Thomas Bertschinger <tahbertschinger@gmail.com>]

This pulls the code for opening a file, after its handle has been
converted to a struct path, into a new helper function.

This function will be used by io_uring once io_uring supports
open_by_handle_at(2).

Signed-off-by: Thomas Bertschinger <tahbertschinger@gmail.com>
---
 fs/fhandle.c  | 21 +++++++++++++++------
 fs/internal.h |  1 +
 2 files changed, 16 insertions(+), 6 deletions(-)

diff --git a/fs/fhandle.c b/fs/fhandle.c
index 36e194dd4cb6..91b0d340a4d1 100644
--- a/fs/fhandle.c
+++ b/fs/fhandle.c
@@ -402,6 +402,20 @@ int handle_to_path(int mountdirfd, struct file_handle *handle,
 	return retval;
 }
 
+struct file *do_filp_path_open(struct path *path, int open_flag)
+{
+	const struct export_operations *eops;
+	struct file *file;
+
+	eops = path->mnt->mnt_sb->s_export_op;
+	if (eops->open)
+		file = eops->open(path, open_flag);
+	else
+		file = file_open_root(path, "", open_flag, 0);
+
+	return file;
+}
+
 static long do_handle_open(int mountdirfd, struct file_handle __user *ufh,
 			   int open_flag)
 {
@@ -409,7 +423,6 @@ static long do_handle_open(int mountdirfd, struct file_handle __user *ufh,
 	long retval = 0;
 	struct path path __free(path_put) = {};
 	struct file *file;
-	const struct export_operations *eops;
 
 	handle = get_user_handle(ufh);
 	if (IS_ERR(handle))
@@ -423,11 +436,7 @@ static long do_handle_open(int mountdirfd, struct file_handle __user *ufh,
 	if (fd < 0)
 		return fd;
 
-	eops = path.mnt->mnt_sb->s_export_op;
-	if (eops->open)
-		file = eops->open(&path, open_flag);
-	else
-		file = file_open_root(&path, "", open_flag, 0);
+	file = do_filp_path_open(&path, open_flag);
 	if (IS_ERR(file))
 		return PTR_ERR(file);
 
diff --git a/fs/internal.h b/fs/internal.h
index ab80f83ded47..599e0d7b450e 100644
--- a/fs/internal.h
+++ b/fs/internal.h
@@ -366,4 +366,5 @@ long do_sys_name_to_handle_at(int dfd, const char __user *name,
 struct file_handle *get_user_handle(struct file_handle __user *ufh);
 int handle_to_path(int mountdirfd, struct file_handle *handle,
 		   struct path *path, unsigned int o_flags);
+struct file *do_filp_path_open(struct path *path, int open_flag);
 #endif /* CONFIG_FHANDLE */
-- 
2.51.0