Merge tag 'for-5.18/io_uring-statx-2022-03-18' of git://git.kernel.dk/linux-block

Pull io_uring statx fixes from Jens Axboe:
 "On top of the main io_uring branch, this is to ensure that the
  filename component of statx is stable after submit.

  That requires a few VFS related changes"

* tag 'for-5.18/io_uring-statx-2022-03-18' of git://git.kernel.dk/linux-block:
  io-uring: Make statx API stable

1 files changed, 20 insertions, 2 deletions

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 5fa736344b67..496a2af7d12c 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -675,7 +675,7 @@ struct io_statx {
 	int				dfd;
 	unsigned int			mask;
 	unsigned int			flags;
-	const char __user		*filename;
+	struct filename			*filename;
 	struct statx __user		*buffer;
 };
 
@@ -5000,6 +5000,8 @@ static int io_fadvise(struct io_kiocb *req, unsigned int issue_flags)
 
 static int io_statx_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 {
+	const char __user *path;
+
 	if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL))
 		return -EINVAL;
 	if (sqe->ioprio || sqe->buf_index || sqe->splice_fd_in)
@@ -5009,10 +5011,22 @@ static int io_statx_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 
 	req->statx.dfd = READ_ONCE(sqe->fd);
 	req->statx.mask = READ_ONCE(sqe->len);
-	req->statx.filename = u64_to_user_ptr(READ_ONCE(sqe->addr));
+	path = u64_to_user_ptr(READ_ONCE(sqe->addr));
 	req->statx.buffer = u64_to_user_ptr(READ_ONCE(sqe->addr2));
 	req->statx.flags = READ_ONCE(sqe->statx_flags);
 
+	req->statx.filename = getname_flags(path,
+					getname_statx_lookup_flags(req->statx.flags),
+					NULL);
+
+	if (IS_ERR(req->statx.filename)) {
+		int ret = PTR_ERR(req->statx.filename);
+
+		req->statx.filename = NULL;
+		return ret;
+	}
+
+	req->flags |= REQ_F_NEED_CLEANUP;
 	return 0;
 }
 
@@ -7112,6 +7126,10 @@ static void io_clean_op(struct io_kiocb *req)
 			putname(req->hardlink.oldpath);
 			putname(req->hardlink.newpath);
 			break;
+		case IORING_OP_STATX:
+			if (req->statx.filename)
+				putname(req->statx.filename);
+			break;
 		}
 	}
 	if ((req->flags & REQ_F_POLLED) && req->apoll) {