[PATCH 01/11] fs: split off vfs_getdents function of getdents64 syscall

Hao Xu
2023-08-27T13:31:28Z

From: Dominique Martinet <asmadeus@codewreck.org>

This splits off the vfs_getdents function from the getdents64 system
call.
This will allow io_uring to call the vfs_getdents function.

Co-developed-by: Stefan Roesch <shr@fb.com>
Signed-off-by: Stefan Roesch <shr@fb.com>
Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
Signed-off-by: Hao Xu <howeyxu@tencent.com>
---
fs/internal.h | 8 ++++++++
fs/readdir.c | 34 ++++++++++++++++++++++++++--------
2 files changed, 34 insertions(+), 8 deletions(-)

diff --git a/fs/internal.h b/fs/internal.h
index f7a3dc111026..b1f66e52d61b 100644
--- a/fs/internal.h
+++ b/fs/internal.h
@@ -304,3 +304,11 @@ ssize_t __kernel_write_iter(struct file *file, struct iov_iter *from, loff_t *po
struct mnt_idmap *alloc_mnt_idmap(struct user_namespace *mnt_userns);
struct mnt_idmap *mnt_idmap_get(struct mnt_idmap *idmap);
void mnt_idmap_put(struct mnt_idmap *idmap);
+
+/*
+ * fs/readdir.c
+ */
+struct linux_dirent64;
+
+int vfs_getdents(struct file *file, struct linux_dirent64 __user *dirent,
+ unsigned int count);
diff --git a/fs/readdir.c b/fs/readdir.c
index b264ce60114d..9592259b7e7f 100644
--- a/fs/readdir.c
+++ b/fs/readdir.c
@@ -21,6 +21,7 @@
#include <linux/unistd.h>
#include <linux/compat.h>
#include <linux/uaccess.h>
+#include "internal.h"

#include <asm/unaligned.h>

@@ -351,10 +352,16 @@ static bool filldir64(struct dir_context *ctx, const char *name, int namlen,
return false;
}

-SYSCALL_DEFINE3(getdents64, unsigned int, fd,
- struct linux_dirent64 __user *, dirent, unsigned int, count)
+
+/**
+ * vfs_getdents - getdents without fdget
+ * @file : pointer to file struct of directory
+ * @dirent : pointer to user directory structure
+ * @count : size of buffer
+ */
+int vfs_getdents(struct file *file, struct linux_dirent64 __user *dirent,
+ unsigned int count)
{
- struct fd f;
struct getdents_callback64 buf = {
.ctx.actor = filldir64,
.count = count,
@@ -362,11 +369,7 @@ SYSCALL_DEFINE3(getdents64, unsigned int, fd,
};
int error;

- f = fdget_pos(fd);
- if (!f.file)
- return -EBADF;
-
- error = iterate_dir(f.file, &buf.ctx);
+ error = iterate_dir(file, &buf.ctx);
if (error >= 0)
error = buf.error;
if (buf.prev_reclen) {
@@ -379,6 +382,21 @@ SYSCALL_DEFINE3(getdents64, unsigned int, fd,
else
error = count - buf.count;
}
+ return error;
+}
+
+SYSCALL_DEFINE3(getdents64, unsigned int, fd,
+ struct linux_dirent64 __user *, dirent, unsigned int, count)
+{
+ struct fd f;
+ int error;
+
+ f = fdget_pos(fd);
+ if (!f.file)
+ return -EBADF;
+
+ error = vfs_getdents(f.file, dirent, count);
+
fdput_pos(f);
return error;
}
--
2.25.1