non-consuming variants of do_{unlinkat,rmdir}()

similar to previous commit; replacements are filename_{unlinkat,rmdir}()

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

Documentation/filesystems/porting.rst

@@ -1341,6 +1341,7 @@ 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(),
-do_symlinkat(), do_mkdirat(), do_mknodat().
+and do_rmdir()) are gone; they are replaced with non-consuming analogues
+(filename_renameat2(), etc.)
+Callers are adjusted - responsibility for dropping the filenames belongs
+to them now.

fs/coredump.c

@@ -895,11 +895,12 @@ static bool coredump_file(struct core_name *cn, struct coredump_params *cprm,
 	 * privs and don't want to unlink another user's coredump.
 	 */
 	if (!coredump_force_suid_safe(cprm)) {
+		CLASS(filename_kernel, name)(cn->corename);
 		/*
 		 * If it doesn't exist, that's fine. If there's some
 		 * other problem, we'll catch it at the filp_open().
 		 */
-		do_unlinkat(AT_FDCWD, getname_kernel(cn->corename));
+		filename_unlinkat(AT_FDCWD, name);
 	}
 
 	/*

fs/init.c

@@ -160,7 +160,8 @@ int __init init_symlink(const char *oldname, const char *newname)
 
 int __init init_unlink(const char *pathname)
 {
-	return do_unlinkat(AT_FDCWD, getname_kernel(pathname));
+	CLASS(filename_kernel, name)(pathname);
+	return filename_unlinkat(AT_FDCWD, name);
 }
 
 int __init init_mkdir(const char *pathname, umode_t mode)
@@ -171,7 +172,8 @@ int __init init_mkdir(const char *pathname, umode_t mode)
 
 int __init init_rmdir(const char *pathname)
 {
-	return do_rmdir(AT_FDCWD, getname_kernel(pathname));
+	CLASS(filename_kernel, name)(pathname);
+	return filename_rmdir(AT_FDCWD, name);
 }
 
 int __init init_utimes(char *filename, struct timespec64 *ts)

fs/internal.h

@@ -54,8 +54,8 @@ extern int finish_clean_context(struct fs_context *fc);
  */
 extern int filename_lookup(int dfd, struct filename *name, unsigned flags,
 			   struct path *path, const struct path *root);
-int do_rmdir(int dfd, struct filename *name);
-int do_unlinkat(int dfd, struct filename *name);
+int filename_rmdir(int dfd, struct filename *name);
+int filename_unlinkat(int dfd, struct filename *name);
 int may_linkat(struct mnt_idmap *idmap, const struct path *link);
 int filename_renameat2(int olddfd, struct filename *oldname, int newdfd,
 		 struct filename *newname, unsigned int flags);

fs/namei.c

@@ -5312,7 +5312,7 @@ out:
 }
 EXPORT_SYMBOL(vfs_rmdir);
 
-int do_rmdir(int dfd, struct filename *name)
+int filename_rmdir(int dfd, struct filename *name)
 {
 	int error;
 	struct dentry *dentry;
@@ -5324,7 +5324,7 @@ int do_rmdir(int dfd, struct filename *name)
 retry:
 	error = filename_parentat(dfd, name, lookup_flags, &path, &last, &type);
 	if (error)
-		goto exit1;
+		return error;
 
 	switch (type) {
 	case LAST_DOTDOT:
@@ -5366,14 +5366,13 @@ exit2:
 		lookup_flags |= LOOKUP_REVAL;
 		goto retry;
 	}
-exit1:
-	putname(name);
 	return error;
 }
 
 SYSCALL_DEFINE1(rmdir, const char __user *, pathname)
 {
-	return do_rmdir(AT_FDCWD, getname(pathname));
+	CLASS(filename, name)(pathname);
+	return filename_rmdir(AT_FDCWD, name);
 }
 
 /**
@@ -5455,7 +5454,7 @@ EXPORT_SYMBOL(vfs_unlink);
  * writeout happening, and we don't want to prevent access to the directory
  * while waiting on the I/O.
  */
-int do_unlinkat(int dfd, struct filename *name)
+int filename_unlinkat(int dfd, struct filename *name)
 {
 	int error;
 	struct dentry *dentry;
@@ -5468,7 +5467,7 @@ int do_unlinkat(int dfd, struct filename *name)
 retry:
 	error = filename_parentat(dfd, name, lookup_flags, &path, &last, &type);
 	if (error)
-		goto exit_putname;
+		return error;
 
 	error = -EISDIR;
 	if (type != LAST_NORM)
@@ -5515,8 +5514,6 @@ exit_path_put:
 		lookup_flags |= LOOKUP_REVAL;
 		goto retry;
 	}
-exit_putname:
-	putname(name);
 	return error;
 }
 
@@ -5525,14 +5522,16 @@ SYSCALL_DEFINE3(unlinkat, int, dfd, const char __user *, pathname, int, flag)
 	if ((flag & ~AT_REMOVEDIR) != 0)
 		return -EINVAL;
 
+	CLASS(filename, name)(pathname);
 	if (flag & AT_REMOVEDIR)
-		return do_rmdir(dfd, getname(pathname));
-	return do_unlinkat(dfd, getname(pathname));
+		return filename_rmdir(dfd, name);
+	return filename_unlinkat(dfd, name);
 }
 
 SYSCALL_DEFINE1(unlink, const char __user *, pathname)
 {
-	return do_unlinkat(AT_FDCWD, getname(pathname));
+	CLASS(filename, name)(pathname);
+	return filename_unlinkat(AT_FDCWD, name);
 }
 
 /**

io_uring/fs.c

@@ -134,14 +134,15 @@ int io_unlinkat_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 int io_unlinkat(struct io_kiocb *req, unsigned int issue_flags)
 {
 	struct io_unlink *un = io_kiocb_to_cmd(req, struct io_unlink);
+	CLASS(filename_complete_delayed, name)(&un->filename);
 	int ret;
 
 	WARN_ON_ONCE(issue_flags & IO_URING_F_NONBLOCK);
 
 	if (un->flags & AT_REMOVEDIR)
-		ret = do_rmdir(un->dfd, complete_getname(&un->filename));
+		ret = filename_rmdir(un->dfd, name);
 	else
-		ret = do_unlinkat(un->dfd, complete_getname(&un->filename));
+		ret = filename_unlinkat(un->dfd, name);
 
 	req->flags &= ~REQ_F_NEED_CLEANUP;
 	io_req_set_res(req, ret, 0);