Commit 7a8721f8 authored by Dmitry Kadashev's avatar Dmitry Kadashev Committed by Jens Axboe
Browse files

io_uring: add support for IORING_OP_SYMLINKAT 



IORING_OP_SYMLINKAT behaves like symlinkat(2) and takes the same flags
and arguments.

Acked-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
Suggested-by: default avatarChristian Brauner <christian.brauner@ubuntu.com>
Link: https://lore.kernel.org/io-uring/20210514145259.wtl4xcsp52woi6ab@wittgenstein/


Signed-off-by: default avatarDmitry Kadashev <dkadashev@gmail.com>
Acked-by: default avatarChristian Brauner <christian.brauner@ubuntu.com>
Link: https://lore.kernel.org/r/20210708063447.3556403-11-dkadashev@gmail.com


[axboe: add splice_fd_in check]
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent e34a02dc

fs/internal.h

+1 −0
Original line number Diff line number Diff line
@@ -77,6 +77,7 @@ int may_linkat(struct user_namespace *mnt_userns, struct path *link); 
int do_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_symlinkat(struct filename *from, int newdfd, struct filename *to);



/*

 * namespace.c

fs/io_uring.c

+67 −0
Original line number Diff line number Diff line
@@ -669,6 +669,13 @@ struct io_mkdir { 
	struct filename			*filename;

};



struct io_symlink {

	struct file			*file;

	int				new_dfd;

	struct filename			*oldpath;

	struct filename			*newpath;

};



struct io_completion {

	struct file			*file;

	u32				cflags;
@@ -829,6 +836,7 @@ struct io_kiocb { 
		struct io_rename	rename;

		struct io_unlink	unlink;

		struct io_mkdir		mkdir;

		struct io_symlink	symlink;

		/* use only after cleaning per-op data, see io_clean_op() */

		struct io_completion	compl;

	};
@@ -1041,6 +1049,7 @@ static const struct io_op_def io_op_defs[] = { 
	[IORING_OP_RENAMEAT] = {},

	[IORING_OP_UNLINKAT] = {},

	[IORING_OP_MKDIRAT] = {},

	[IORING_OP_SYMLINKAT] = {},

};



/* requests with any of those set should undergo io_disarm_next() */
@@ -3655,6 +3664,55 @@ static int io_mkdirat(struct io_kiocb *req, int issue_flags) 
	return 0;

}



static int io_symlinkat_prep(struct io_kiocb *req,

			    const struct io_uring_sqe *sqe)

{

	struct io_symlink *sl = &req->symlink;

	const char __user *oldpath, *newpath;



	if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL))

		return -EINVAL;

	if (sqe->ioprio || sqe->len || sqe->rw_flags || sqe->buf_index ||

	    sqe->splice_fd_in)

		return -EINVAL;

	if (unlikely(req->flags & REQ_F_FIXED_FILE))

		return -EBADF;



	sl->new_dfd = READ_ONCE(sqe->fd);

	oldpath = u64_to_user_ptr(READ_ONCE(sqe->addr));

	newpath = u64_to_user_ptr(READ_ONCE(sqe->addr2));



	sl->oldpath = getname(oldpath);

	if (IS_ERR(sl->oldpath))

		return PTR_ERR(sl->oldpath);



	sl->newpath = getname(newpath);

	if (IS_ERR(sl->newpath)) {

		putname(sl->oldpath);

		return PTR_ERR(sl->newpath);

	}



	req->flags |= REQ_F_NEED_CLEANUP;

	return 0;

}



static int io_symlinkat(struct io_kiocb *req, int issue_flags)

{

	struct io_symlink *sl = &req->symlink;

	int ret;



	if (issue_flags & IO_URING_F_NONBLOCK)

		return -EAGAIN;



	ret = do_symlinkat(sl->oldpath, sl->new_dfd, sl->newpath);



	req->flags &= ~REQ_F_NEED_CLEANUP;

	if (ret < 0)

		req_set_fail(req);

	io_req_complete(req, ret);

	return 0;

}



static int io_shutdown_prep(struct io_kiocb *req,

			    const struct io_uring_sqe *sqe)

{
@@ -6054,6 +6112,8 @@ static int io_req_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) 
		return io_unlinkat_prep(req, sqe);

	case IORING_OP_MKDIRAT:

		return io_mkdirat_prep(req, sqe);

	case IORING_OP_SYMLINKAT:

		return io_symlinkat_prep(req, sqe);

	}



	printk_once(KERN_WARNING "io_uring: unhandled opcode %d\n",
@@ -6220,6 +6280,10 @@ static void io_clean_op(struct io_kiocb *req) 
		case IORING_OP_MKDIRAT:

			putname(req->mkdir.filename);

			break;

		case IORING_OP_SYMLINKAT:

			putname(req->symlink.oldpath);

			putname(req->symlink.newpath);

			break;

		}

	}

	if ((req->flags & REQ_F_POLLED) && req->apoll) {
@@ -6351,6 +6415,9 @@ static int io_issue_sqe(struct io_kiocb *req, unsigned int issue_flags) 
	case IORING_OP_MKDIRAT:

		ret = io_mkdirat(req, issue_flags);

		break;

	case IORING_OP_SYMLINKAT:

		ret = io_symlinkat(req, issue_flags);

		break;

	default:

		ret = -EINVAL;

		break;

fs/namei.c

+1 −2
Original line number Diff line number Diff line
@@ -4223,8 +4223,7 @@ int vfs_symlink(struct user_namespace *mnt_userns, struct inode *dir, 
}

EXPORT_SYMBOL(vfs_symlink);



static int do_symlinkat(struct filename *from, int newdfd,

		  struct filename *to)

int do_symlinkat(struct filename *from, int newdfd, struct filename *to)

{

	int error;

	struct dentry *dentry;

include/uapi/linux/io_uring.h

+1 −0
Original line number Diff line number Diff line
@@ -134,6 +134,7 @@ enum { 
	IORING_OP_RENAMEAT,

	IORING_OP_UNLINKAT,

	IORING_OP_MKDIRAT,

	IORING_OP_SYMLINKAT,



	/* this goes last, obviously */

	IORING_OP_LAST,