non-consuming variant of do_symlinkat()

similar to previous commit; replacement is filename_symlinkat()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Documentation/filesystems/porting.rst

@@ -1342,4 +1342,5 @@ in-tree filesystems have done).
 fs/namei.c primitives that consume filesystem references (do_renameat2(),
 do_linkat(), do_symlinkat(), do_mkdirat(), do_mknodat(), do_unlinkat()
 and do_rmdir()) are getting replaced with non-consuming analogues
-(filename_renameat2(), etc.)  Replaced so far: do_renameat2(), do_linkat().
+(filename_renameat2(), etc.)  Replaced so far: do_renameat2(), do_linkat(),
+do_symlinkat().

fs/init.c

@@ -152,8 +152,9 @@ int __init init_link(const char *oldname, const char *newname)
 
 int __init init_symlink(const char *oldname, const char *newname)
 {
-	return do_symlinkat(getname_kernel(oldname), AT_FDCWD,
-			    getname_kernel(newname));
+	CLASS(filename_kernel, old)(oldname);
+	CLASS(filename_kernel, new)(newname);
+	return filename_symlinkat(old, AT_FDCWD, new);
 }
 
 int __init init_unlink(const char *pathname)

fs/internal.h

@@ -61,7 +61,7 @@ int filename_renameat2(int olddfd, struct filename *oldname, int newdfd,
 		 struct filename *newname, unsigned int flags);
 int do_mkdirat(int dfd, struct filename *name, umode_t mode);
 int do_mknodat(int dfd, struct filename *name, umode_t mode, unsigned int dev);
-int do_symlinkat(struct filename *from, int newdfd, struct filename *to);
+int filename_symlinkat(struct filename *from, int newdfd, struct filename *to);
 int filename_linkat(int olddfd, struct filename *old, int newdfd,
 			struct filename *new, int flags);
 int vfs_tmpfile(struct mnt_idmap *idmap,

fs/namei.c

@@ -5581,7 +5581,7 @@ int vfs_symlink(struct mnt_idmap *idmap, struct inode *dir,
 }
 EXPORT_SYMBOL(vfs_symlink);
 
-int do_symlinkat(struct filename *from, int newdfd, struct filename *to)
+int filename_symlinkat(struct filename *from, int newdfd, struct filename *to)
 {
 	int error;
 	struct dentry *dentry;
@@ -5589,15 +5589,13 @@ int do_symlinkat(struct filename *from, int newdfd, struct filename *to)
 	unsigned int lookup_flags = 0;
 	struct delegated_inode delegated_inode = { };
 
-	if (IS_ERR(from)) {
-		error = PTR_ERR(from);
-		goto out_putnames;
-	}
+	if (IS_ERR(from))
+		return PTR_ERR(from);
+
 retry:
 	dentry = filename_create(newdfd, to, &path, lookup_flags);
-	error = PTR_ERR(dentry);
 	if (IS_ERR(dentry))
-		goto out_putnames;
+		return PTR_ERR(dentry);
 
 	error = security_path_symlink(&path, dentry, from->name);
 	if (!error)
@@ -5613,21 +5611,22 @@ retry:
 		lookup_flags |= LOOKUP_REVAL;
 		goto retry;
 	}
-out_putnames:
-	putname(to);
-	putname(from);
 	return error;
 }
 
 SYSCALL_DEFINE3(symlinkat, const char __user *, oldname,
 		int, newdfd, const char __user *, newname)
 {
-	return do_symlinkat(getname(oldname), newdfd, getname(newname));
+	CLASS(filename, old)(oldname);
+	CLASS(filename, new)(newname);
+	return filename_symlinkat(old, newdfd, new);
 }
 
 SYSCALL_DEFINE2(symlink, const char __user *, oldname, const char __user *, newname)
 {
-	return do_symlinkat(getname(oldname), AT_FDCWD, getname(newname));
+	CLASS(filename, old)(oldname);
+	CLASS(filename, new)(newname);
+	return filename_symlinkat(old, AT_FDCWD, new);
 }
 
 /**

io_uring/fs.c

@@ -233,12 +233,13 @@ int io_symlinkat_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 int io_symlinkat(struct io_kiocb *req, unsigned int issue_flags)
 {
 	struct io_link *sl = io_kiocb_to_cmd(req, struct io_link);
+	CLASS(filename_complete_delayed, old)(&sl->oldpath);
+	CLASS(filename_complete_delayed, new)(&sl->newpath);
 	int ret;
 
 	WARN_ON_ONCE(issue_flags & IO_URING_F_NONBLOCK);
 
-	ret = do_symlinkat(complete_getname(&sl->oldpath), sl->new_dfd,
-			   complete_getname(&sl->newpath));
+	ret = filename_symlinkat(old, sl->new_dfd, new);
 
 	req->flags &= ~REQ_F_NEED_CLEANUP;
 	io_req_set_res(req, ret, 0);