[PATCH v1 4/5] io_uring: add fsetxattr and setxattr support

Stefan Roesch
2021-11-29T22:13:04Z

Summary:

This adds support to io_uring for the following API's:
- fsetxattr
- setxattr

Signed-off-by: Stefan Roesch <shr@fb.com>
---
fs/io_uring.c | 173 ++++++++++++++++++++++++++++++++++
include/uapi/linux/io_uring.h | 6 +-
2 files changed, 178 insertions(+), 1 deletion(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 568729677e25..4a18431e13a3 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -81,6 +81,7 @@
#include <linux/tracehook.h>
#include <linux/audit.h>
#include <linux/security.h>
+#include <linux/xattr.h>

#define CREATE_TRACE_POINTS
#include <trace/events/io_uring.h>
@@ -717,6 +718,13 @@ struct io_async_rw {
struct wait_page_queue wpq;
};

+struct io_xattr {
+ struct file *file;
+ struct xattr_ctx ctx;
+ void *value;
+ struct filename *filename;
+};
+
enum {
REQ_F_FIXED_FILE_BIT = IOSQE_FIXED_FILE_BIT,
REQ_F_IO_DRAIN_BIT = IOSQE_IO_DRAIN_BIT,
@@ -856,6 +864,7 @@ struct io_kiocb {
struct io_mkdir mkdir;
struct io_symlink symlink;
struct io_hardlink hardlink;
+ struct io_xattr xattr;
};

u8 opcode;
@@ -1105,6 +1114,10 @@ static const struct io_op_def io_op_defs[] = {
[IORING_OP_MKDIRAT] = {},
[IORING_OP_SYMLINKAT] = {},
[IORING_OP_LINKAT] = {},
+ [IORING_OP_FSETXATTR] = {
+ .needs_file = 1
+ },
+ [IORING_OP_SETXATTR] = {},
};

/* requests with any of those set should undergo io_disarm_next() */
@@ -3818,6 +3831,146 @@ static int io_renameat(struct io_kiocb *req, unsigned int issue_flags)
return 0;
}

+static int __io_setxattr_prep(struct io_kiocb *req,
+ const struct io_uring_sqe *sqe,
+ struct user_namespace *user_ns)
+{
+ struct io_xattr *ix = &req->xattr;
+ const char __user *name;
+ void *ret;
+
+ if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL))
+ return -EINVAL;
+ if (unlikely(sqe->ioprio))
+ return -EINVAL;
+ if (unlikely(req->flags & REQ_F_FIXED_FILE))
+ return -EBADF;
+
+ ix->filename = NULL;
+ name = u64_to_user_ptr(READ_ONCE(sqe->addr));
+ ix->ctx.value = u64_to_user_ptr(READ_ONCE(sqe->addr2));
+ ix->ctx.size = READ_ONCE(sqe->len);
+ ix->ctx.flags = READ_ONCE(sqe->xattr_flags);
+
+ ix->ctx.name = kmalloc(XATTR_NAME_MAX + 1, GFP_KERNEL);
+ if (!ix->ctx.name)
+ return -ENOMEM;
+ ix->ctx.name_sz = XATTR_NAME_MAX + 1;
+
+ ret = setxattr_setup(user_ns, name, &ix->ctx);
+ if (IS_ERR(ret)) {
+ kfree(ix->ctx.name);
+ return PTR_ERR(ret);
+ }
+
+ ix->value = ret;
+ req->flags |= REQ_F_NEED_CLEANUP;
+ return 0;
+}
+
+static int io_setxattr_prep(struct io_kiocb *req,
+ const struct io_uring_sqe *sqe)
+{
+ struct io_xattr *ix = &req->xattr;
+ const char __user *path;
+ int ret;
+
+ ret = __io_setxattr_prep(req, sqe, current_user_ns());
+ if (ret)
+ return ret;
+
+ path = u64_to_user_ptr(READ_ONCE(sqe->addr3));
+
+ ix->filename = getname_flags(path, LOOKUP_FOLLOW, NULL);
+ if (IS_ERR(ix->filename)) {
+ ret = PTR_ERR(ix->filename);
+ ix->filename = NULL;
+ }
+
+ return ret;
+}
+
+static int io_fsetxattr_prep(struct io_kiocb *req,
+ const struct io_uring_sqe *sqe)
+{
+ if (!req->file)
+ return -EBADF;
+
+ return __io_setxattr_prep(req, sqe, file_mnt_user_ns(req->file));
+}
+
+static int __io_setxattr(struct io_kiocb *req, unsigned int issue_flags,
+ struct path *path)
+{
+ struct io_xattr *ix = &req->xattr;
+ int ret;
+
+ ret = mnt_want_write(path->mnt);
+ if (!ret) {
+ ret = vfs_setxattr(mnt_user_ns(path->mnt), path->dentry,
+ ix->ctx.name, ix->value, ix->ctx.size,
+ ix->ctx.flags);
+ mnt_drop_write(path->mnt);
+ }
+
+ return ret;
+}
+
+static int io_fsetxattr(struct io_kiocb *req, unsigned int issue_flags)
+{
+ struct io_xattr *ix = &req->xattr;
+ int ret;
+
+ if (issue_flags & IO_URING_F_NONBLOCK)
+ return -EAGAIN;
+
+ ret = __io_setxattr(req, issue_flags, &req->file->f_path);
+
+ req->flags &= ~REQ_F_NEED_CLEANUP;
+ kfree(ix->ctx.name);
+
+ if (ix->value)
+ kvfree(ix->value);
+ if (ret < 0)
+ req_set_fail(req);
+
+ io_req_complete(req, ret);
+ return 0;
+}
+
+static int io_setxattr(struct io_kiocb *req, unsigned int issue_flags)
+{
+ struct io_xattr *ix = &req->xattr;
+ unsigned int lookup_flags = LOOKUP_FOLLOW;
+ struct path path;
+ int ret;
+
+ if (issue_flags & IO_URING_F_NONBLOCK)
+ return -EAGAIN;
+
+retry:
+ ret = user_path_at_empty(AT_FDCWD, ix->filename, lookup_flags, &path);
+ if (!ret) {
+ ret = __io_setxattr(req, issue_flags, &path);
+ path_put(&path);
+ if (retry_estale(ret, lookup_flags)) {
+ lookup_flags |= LOOKUP_REVAL;
+ goto retry;
+ }
+ }
+
+ req->flags &= ~REQ_F_NEED_CLEANUP;
+ kfree(ix->ctx.name);
+
+ if (ix->value)
+ kvfree(ix->value);
+ if (ret < 0)
+ req_set_fail(req);
+
+ io_req_complete(req, ret);
+ return 0;
+}
+
static int io_unlinkat_prep(struct io_kiocb *req,
const struct io_uring_sqe *sqe)
{
@@ -6531,6 +6684,10 @@ static int io_req_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
return io_symlinkat_prep(req, sqe);
case IORING_OP_LINKAT:
return io_linkat_prep(req, sqe);
+ case IORING_OP_FSETXATTR:
+ return io_fsetxattr_prep(req, sqe);
+ case IORING_OP_SETXATTR:
+ return io_setxattr_prep(req, sqe);
}

printk_once(KERN_WARNING "io_uring: unhandled opcode %d\n",
@@ -6674,6 +6831,15 @@ static void io_clean_op(struct io_kiocb *req)
putname(req->hardlink.oldpath);
putname(req->hardlink.newpath);
break;
+ case IORING_OP_SETXATTR:
+ if (req->xattr.filename)
+ putname(req->xattr.filename);
+ fallthrough;
+ case IORING_OP_FSETXATTR:
+ kfree(req->xattr.ctx.name);
+ if (req->xattr.value)
+ kvfree(req->xattr.value);
+ break;
}
}
if ((req->flags & REQ_F_POLLED) && req->apoll) {
@@ -6816,6 +6982,12 @@ static int io_issue_sqe(struct io_kiocb *req, unsigned int issue_flags)
case IORING_OP_LINKAT:
ret = io_linkat(req, issue_flags);
break;
+ case IORING_OP_FSETXATTR:
+ ret = io_fsetxattr(req, issue_flags);
+ break;
+ case IORING_OP_SETXATTR:
+ ret = io_setxattr(req, issue_flags);
+ break;
default:
ret = -EINVAL;
break;
@@ -11183,6 +11355,7 @@ static int __init io_uring_init(void)
BUILD_BUG_SQE_ELEM(42, __u16, personality);
BUILD_BUG_SQE_ELEM(44, __s32, splice_fd_in);
BUILD_BUG_SQE_ELEM(44, __u32, file_index);
+ BUILD_BUG_SQE_ELEM(48, __u64, addr3);

BUILD_BUG_ON(sizeof(struct io_uring_files_update) !=
sizeof(struct io_uring_rsrc_update));
diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h
index 787f491f0d2a..dbf473900da2 100644
--- a/include/uapi/linux/io_uring.h
+++ b/include/uapi/linux/io_uring.h
@@ -45,6 +45,7 @@ struct io_uring_sqe {
__u32 rename_flags;
__u32 unlink_flags;
__u32 hardlink_flags;
+ __u32 xattr_flags;
};
__u64 user_data; /* data to be passed back at completion time */
/* pack this to avoid bogus arm OABI complaints */
@@ -60,7 +61,8 @@ struct io_uring_sqe {
__s32 splice_fd_in;
__u32 file_index;
};
- __u64 __pad2[2];
+ __u64 addr3;
+ __u64 __pad2[1];
};

enum {
@@ -143,6 +145,8 @@ enum {
IORING_OP_MKDIRAT,
IORING_OP_SYMLINKAT,
IORING_OP_LINKAT,
+ IORING_OP_FSETXATTR,
+ IORING_OP_SETXATTR,

/* this goes last, obviously */
IORING_OP_LAST,
--
2.30.2