From cf30da90bc3a26911d369f199411f38b701394de Mon Sep 17 00:00:00 2001
From: Dmitry Kadashev <dkadashev@gmail.com>
Date: Thu, 8 Jul 2021 13:34:47 +0700
Subject: [PATCH] io_uring: add support for IORING_OP_LINKAT
Git-commit: cf30da90bc3a26911d369f199411f38b701394de
Patch-mainline: v5.15-rc1
References: bsc#1205205
IORING_OP_LINKAT behaves like linkat(2) and takes the same flags and
arguments.
In some internal places 'hardlink' is used instead of 'link' to avoid
confusion with the SQE links. Name 'link' conflicts with the existing
'link' member of io_kiocb.
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Suggested-by: Christian Brauner <christian.brauner@ubuntu.com>
Link: https://lore.kernel.org/io-uring/20210514145259.wtl4xcsp52woi6ab@wittgenstein/
Signed-off-by: Dmitry Kadashev <dkadashev@gmail.com>
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
Link: https://lore.kernel.org/r/20210708063447.3556403-12-dkadashev@gmail.com
[axboe: add splice_fd_in check]
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Gabriel Krisman Bertazi <krisman@suse.de>
---
fs/internal.h | 2 +
fs/io_uring.c | 71 +++++++++++++++++++++++++++++++++++
fs/namei.c | 2 +-
include/uapi/linux/io_uring.h | 2 +
4 files changed, 76 insertions(+), 1 deletion(-)
diff --git a/fs/internal.h b/fs/internal.h
index 2f9750aefbd6..2bb444600852 100644
--- a/fs/internal.h
+++ b/fs/internal.h
@@ -78,6 +78,8 @@ 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);
+int do_linkat(int olddfd, struct filename *old, int newdfd,
+ struct filename *new, int flags);
/*
* namespace.c
diff --git a/fs/io_uring.c b/fs/io_uring.c
index 33941df9084b..a89bbffbe042 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -676,6 +676,15 @@ struct io_symlink {
struct filename *newpath;
};
+struct io_hardlink {
+ struct file *file;
+ int old_dfd;
+ int new_dfd;
+ struct filename *oldpath;
+ struct filename *newpath;
+ int flags;
+};
+
struct io_completion {
struct file *file;
u32 cflags;
@@ -837,6 +846,7 @@ struct io_kiocb {
struct io_unlink unlink;
struct io_mkdir mkdir;
struct io_symlink symlink;
+ struct io_hardlink hardlink;
/* use only after cleaning per-op data, see io_clean_op() */
struct io_completion compl;
};
@@ -1050,6 +1060,7 @@ static const struct io_op_def io_op_defs[] = {
[IORING_OP_UNLINKAT] = {},
[IORING_OP_MKDIRAT] = {},
[IORING_OP_SYMLINKAT] = {},
+ [IORING_OP_LINKAT] = {},
};
/* requests with any of those set should undergo io_disarm_next() */
@@ -3713,6 +3724,57 @@ static int io_symlinkat(struct io_kiocb *req, int issue_flags)
return 0;
}
+static int io_linkat_prep(struct io_kiocb *req,
+ const struct io_uring_sqe *sqe)
+{
+ struct io_hardlink *lnk = &req->hardlink;
+ const char __user *oldf, *newf;
+
+ if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL))
+ return -EINVAL;
+ if (sqe->ioprio || sqe->rw_flags || sqe->buf_index || sqe->splice_fd_in)
+ return -EINVAL;
+ if (unlikely(req->flags & REQ_F_FIXED_FILE))
+ return -EBADF;
+
+ lnk->old_dfd = READ_ONCE(sqe->fd);
+ lnk->new_dfd = READ_ONCE(sqe->len);
+ oldf = u64_to_user_ptr(READ_ONCE(sqe->addr));
+ newf = u64_to_user_ptr(READ_ONCE(sqe->addr2));
+ lnk->flags = READ_ONCE(sqe->hardlink_flags);
+
+ lnk->oldpath = getname(oldf);
+ if (IS_ERR(lnk->oldpath))
+ return PTR_ERR(lnk->oldpath);
+
+ lnk->newpath = getname(newf);
+ if (IS_ERR(lnk->newpath)) {
+ putname(lnk->oldpath);
+ return PTR_ERR(lnk->newpath);
+ }
+
+ req->flags |= REQ_F_NEED_CLEANUP;
+ return 0;
+}
+
+static int io_linkat(struct io_kiocb *req, int issue_flags)
+{
+ struct io_hardlink *lnk = &req->hardlink;
+ int ret;
+
+ if (issue_flags & IO_URING_F_NONBLOCK)
+ return -EAGAIN;
+
+ ret = do_linkat(lnk->old_dfd, lnk->oldpath, lnk->new_dfd,
+ lnk->newpath, lnk->flags);
+
+ 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)
{
@@ -6114,6 +6176,8 @@ static int io_req_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
return io_mkdirat_prep(req, sqe);
case IORING_OP_SYMLINKAT:
return io_symlinkat_prep(req, sqe);
+ case IORING_OP_LINKAT:
+ return io_linkat_prep(req, sqe);
}
printk_once(KERN_WARNING "io_uring: unhandled opcode %d\n",
@@ -6284,6 +6348,10 @@ static void io_clean_op(struct io_kiocb *req)
putname(req->symlink.oldpath);
putname(req->symlink.newpath);
break;
+ case IORING_OP_LINKAT:
+ putname(req->hardlink.oldpath);
+ putname(req->hardlink.newpath);
+ break;
}
}
if ((req->flags & REQ_F_POLLED) && req->apoll) {
@@ -6418,6 +6486,9 @@ static int io_issue_sqe(struct io_kiocb *req, unsigned int issue_flags)
case IORING_OP_SYMLINKAT:
ret = io_symlinkat(req, issue_flags);
break;
+ case IORING_OP_LINKAT:
+ ret = io_linkat(req, issue_flags);
+ break;
default:
ret = -EINVAL;
break;
diff --git a/fs/namei.c b/fs/namei.c
index 803fc95b7658..0718e1e87eb4 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -4368,7 +4368,7 @@ EXPORT_SYMBOL(vfs_link);
* with linux 2.0, and to avoid hard-linking to directories
* and other special files. --ADM
*/
-static int do_linkat(int olddfd, struct filename *old, int newdfd,
+int do_linkat(int olddfd, struct filename *old, int newdfd,
struct filename *new, int flags)
{
struct user_namespace *mnt_userns;
diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h
index 61fd347ab176..10eb38d2864f 100644
--- a/include/uapi/linux/io_uring.h
+++ b/include/uapi/linux/io_uring.h
@@ -44,6 +44,7 @@ struct io_uring_sqe {
__u32 splice_flags;
__u32 rename_flags;
__u32 unlink_flags;
+ __u32 hardlink_flags;
};
__u64 user_data; /* data to be passed back at completion time */
/* pack this to avoid bogus arm OABI complaints */
@@ -135,6 +136,7 @@ enum {
IORING_OP_UNLINKAT,
IORING_OP_MKDIRAT,
IORING_OP_SYMLINKAT,
+ IORING_OP_LINKAT,
/* this goes last, obviously */
IORING_OP_LAST,
--
2.35.3