[PATCH v3 2/3] fs: split off vfs_getdents function of getdents64 syscall

Stefan Roesch
2021-11-25T23:28:09Z

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

Signed-off-by: Stefan Roesch <shr@fb.com>
---
fs/internal.h | 8 ++++++++
fs/readdir.c | 36 ++++++++++++++++++++++++++++--------
2 files changed, 36 insertions(+), 8 deletions(-)

diff --git a/fs/internal.h b/fs/internal.h
index 7979ff8d168c..355be993b9f1 100644
--- a/fs/internal.h
+++ b/fs/internal.h
@@ -194,3 +194,11 @@ long splice_file_to_pipe(struct file *in,
struct pipe_inode_info *opipe,
loff_t *offset,
size_t len, unsigned int flags);
+
+/*
+ * fs/readdir.c
+ */
+struct linux_dirent64;
+
+int vfs_getdents(struct file *file, struct linux_dirent64 __user *dirent,
+ unsigned int count, s64 pos);
diff --git a/fs/readdir.c b/fs/readdir.c
index e9c197edf73a..c9ee066cd677 100644
--- a/fs/readdir.c
+++ b/fs/readdir.c
@@ -368,22 +368,26 @@ static int filldir64(struct dir_context *ctx, const char *name, int namlen,
return -EFAULT;
}

-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
+ * @ctx_pos : if file pos is used, pass -1,
+ * if ctx pos is used, pass ctx pos
+ */
+int vfs_getdents(struct file *file, struct linux_dirent64 __user *dirent,
+ unsigned int count, s64 ctx_pos)
{
- struct fd f;
struct getdents_callback64 buf = {
.ctx.actor = filldir64,
+ .ctx.pos = ctx_pos,
.count = count,
.current_dir = dirent
};
int error;

- f = fdget_pos(fd);
- if (!f.file)
- return -EBADF;
-
- error = iterate_dir(f.file, &buf.ctx);
+ error = do_iterate_dir(file, &buf.ctx, ctx_pos < 0);
if (error >= 0)
error = buf.error;
if (buf.prev_reclen) {
@@ -396,6 +400,22 @@ 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, -1);
+
fdput_pos(f);
return error;
}
--
2.30.2