[PATCH -next] io_uring: add support for fchmod

[PATCH -next] io_uring: add support for fchmod

[lizetao]

Adds support for doing chmod through io_uring. IORING_OP_FCHMOD behaves like fchmod(2) and takes the same arguments.

Signed-off-by: Li Zetao <lizetao1@huawei.com>
---
 include/uapi/linux/io_uring.h |  1 +
 io_uring/fs.c                 | 32 ++++++++++++++++++++++++++++++++
 io_uring/fs.h                 |  3 +++
 io_uring/opdef.c              |  8 ++++++++
 4 files changed, 44 insertions(+)

diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h index 5d08435b95a8..de5cce11f937 100644
--- a/include/uapi/linux/io_uring.h
+++ b/include/uapi/linux/io_uring.h
@@ -262,6 +262,7 @@ enum io_uring_op {
 	IORING_OP_FTRUNCATE,
 	IORING_OP_BIND,
 	IORING_OP_LISTEN,
+	IORING_OP_FCHMOD,
 
 	/* this goes last, obviously */
 	IORING_OP_LAST,
diff --git a/io_uring/fs.c b/io_uring/fs.c index eccea851dd5a..835f66fb75ff 100644
--- a/io_uring/fs.c
+++ b/io_uring/fs.c
@@ -47,6 +47,11 @@ struct io_link {
 	int				flags;
 };
 
+struct io_fchmod {
+	struct file			*file;
+	umode_t				mode;
+};
+
 int io_renameat_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)  {
 	struct io_rename *ren = io_kiocb_to_cmd(req, struct io_rename); @@ -291,3 +296,30 @@ void io_link_cleanup(struct io_kiocb *req)
 	putname(sl->oldpath);
 	putname(sl->newpath);
 }
+
+int io_fchmod_prep(struct io_kiocb *req, const struct io_uring_sqe 
+*sqe) {
+	struct io_fchmod *fc = io_kiocb_to_cmd(req, struct io_fchmod);
+
+	if (unlikely(sqe->off || sqe->addr || sqe->rw_flags ||
+		     sqe->buf_index || sqe->splice_fd_in))
+		return -EINVAL;
+	if (unlikely(req->flags & REQ_F_FIXED_FILE))
+		return -EBADF;
+
+	fc->mode = READ_ONCE(sqe->len);
+	req->flags |= REQ_F_FORCE_ASYNC;
+	return 0;
+}
+
+int io_fchmod(struct io_kiocb *req, unsigned int issue_flags) {
+	struct io_fchmod *fc = io_kiocb_to_cmd(req, struct io_fchmod);
+	int ret;
+
+	WARN_ON_ONCE(issue_flags & IO_URING_F_NONBLOCK);
+
+	ret = vfs_fchmod(req->file, fc->mode);
+	io_req_set_res(req, ret, 0);
+	return IOU_OK;
+}
diff --git a/io_uring/fs.h b/io_uring/fs.h index 0bb5efe3d6bb..bc7d95e77b2f 100644
--- a/io_uring/fs.h
+++ b/io_uring/fs.h
@@ -18,3 +18,6 @@ int io_symlinkat(struct io_kiocb *req, unsigned int issue_flags);  int io_linkat_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe);  int io_linkat(struct io_kiocb *req, unsigned int issue_flags);  void io_link_cleanup(struct io_kiocb *req);
+
+int io_fchmod_prep(struct io_kiocb *req, const struct io_uring_sqe 
+*sqe); int io_fchmod(struct io_kiocb *req, unsigned int issue_flags);
diff --git a/io_uring/opdef.c b/io_uring/opdef.c index 3de75eca1c92..eb5bf831513c 100644
--- a/io_uring/opdef.c
+++ b/io_uring/opdef.c
@@ -515,6 +515,11 @@ const struct io_issue_def io_issue_defs[] = {
 		.prep			= io_eopnotsupp_prep,
 #endif
 	},
+	[IORING_OP_FCHMOD] = {
+		.needs_file		= 1,
+		.prep			= io_fchmod_prep,
+		.issue			= io_fchmod,
+	},
 };
 
 const struct io_cold_def io_cold_defs[] = { @@ -744,6 +749,9 @@ const struct io_cold_def io_cold_defs[] = {
 	[IORING_OP_LISTEN] = {
 		.name			= "LISTEN",
 	},
+	[IORING_OP_FCHMOD] = {
+		.name			= "FCHMOD",
+	},
 };
 
 const char *io_uring_get_opcode(u8 opcode)
--
2.34.1

Re: [PATCH -next] io_uring: add support for fchmod

[Jens Axboe]

On 11/19/24 1:12 AM, lizetao wrote:
> Adds support for doing chmod through io_uring. IORING_OP_FCHMOD
> behaves like fchmod(2) and takes the same arguments.

Looks pretty straight forward. The only downside is the forced use of 
REQ_F_FORCE_ASYNC - did you look into how feasible it would be to allow
non-blocking issue of this? Would imagine the majority of fchmod calls
end up not blocking in the first place.

-- 
Jens Axboe