io_uring: add fgetxattr and getxattr support

This adds support to io_uring for the fgetxattr and getxattr API.

Signed-off-by: Stefan Roesch <shr@fb.com>
Link: https://lore.kernel.org/r/20211223235123.4092764-6-shr@fb.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/fs/io_uring.c b/fs/io_uring.c
index cde0013e59ed6bda6bda7876c1981249293912f8..0e0ea0ed1ac1cdefef0143bc32d037f11bebde11 100644 (file)
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -1130,6 +1130,10 @@ static const struct io_op_def io_op_defs[] = {
                .needs_file = 1
        },
        [IORING_OP_SETXATTR] = {},
+       [IORING_OP_FGETXATTR] = {
+               .needs_file = 1
+       },
+       [IORING_OP_GETXATTR] = {},
 };
 
 /* requests with any of those set should undergo io_disarm_next() */
@@ -3869,6 +3873,134 @@ static int io_renameat(struct io_kiocb *req, unsigned int issue_flags)
        return 0;
 }
 
+static int __io_getxattr_prep(struct io_kiocb *req,
+                             const struct io_uring_sqe *sqe)
+{
+       struct io_xattr *ix = &req->xattr;
+       const char __user *name;
+       int 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;
+       ix->value = 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);
+
+       if (ix->ctx.flags)
+               return -EINVAL;
+
+       ix->ctx.kname = kmalloc(sizeof(*ix->ctx.kname), GFP_KERNEL);
+       if (!ix->ctx.kname)
+               return -ENOMEM;
+
+       ret = strncpy_from_user(ix->ctx.kname->name, name,
+                               sizeof(ix->ctx.kname->name));
+       if (!ret || ret == sizeof(ix->ctx.kname->name))
+               ret = -ERANGE;
+       if (ret < 0) {
+               kfree(ix->ctx.kname);
+               return ret;
+       }
+
+       req->flags |= REQ_F_NEED_CLEANUP;
+       return 0;
+}
+
+static int io_fgetxattr_prep(struct io_kiocb *req,
+                            const struct io_uring_sqe *sqe)
+{
+       return __io_getxattr_prep(req, sqe);
+}
+
+static int io_getxattr_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_getxattr_prep(req, sqe);
+       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_fgetxattr(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 = do_getxattr(mnt_user_ns(req->file->f_path.mnt),
+                       req->file->f_path.dentry,
+                       ix->ctx.kname->name,
+                       (void __user *)ix->ctx.value,
+                       ix->ctx.size);
+
+       req->flags &= ~REQ_F_NEED_CLEANUP;
+       kfree(ix->ctx.kname);
+       if (ret < 0)
+               req_set_fail(req);
+
+       io_req_complete(req, ret);
+       return 0;
+}
+
+static int io_getxattr(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 = do_user_path_at_empty(AT_FDCWD, ix->filename, lookup_flags, &path);
+       if (!ret) {
+               ret = do_getxattr(mnt_user_ns(path.mnt),
+                               path.dentry,
+                               ix->ctx.kname->name,
+                               (void __user *)ix->ctx.value,
+                               ix->ctx.size);
+
+               path_put(&path);
+               if (retry_estale(ret, lookup_flags)) {
+                       lookup_flags |= LOOKUP_REVAL;
+                       goto retry;
+               }
+       }
+       putname(ix->filename);
+
+       req->flags &= ~REQ_F_NEED_CLEANUP;
+       kfree(ix->ctx.kname);
+       if (ret < 0)
+               req_set_fail(req);
+
+       io_req_complete(req, ret);
+       return 0;
+}
+
 static int __io_setxattr_prep(struct io_kiocb *req,
                        const struct io_uring_sqe *sqe)
 {
@@ -6739,6 +6871,10 @@ static int io_req_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
                return io_fsetxattr_prep(req, sqe);
        case IORING_OP_SETXATTR:
                return io_setxattr_prep(req, sqe);
+       case IORING_OP_FGETXATTR:
+               return io_fgetxattr_prep(req, sqe);
+       case IORING_OP_GETXATTR:
+               return io_getxattr_prep(req, sqe);
        }
 
        printk_once(KERN_WARNING "io_uring: unhandled opcode %d\n",
@@ -6888,6 +7024,13 @@ static void io_clean_op(struct io_kiocb *req)
                        kfree(req->xattr.ctx.kname);
                        kvfree(req->xattr.value);
                        break;
+               case IORING_OP_GETXATTR:
+                       if (req->xattr.filename)
+                               putname(req->xattr.filename);
+                       fallthrough;
+               case IORING_OP_FGETXATTR:
+                       kfree(req->xattr.ctx.kname);
+                       break;
                }
        }
        if ((req->flags & REQ_F_POLLED) && req->apoll) {
@@ -7039,6 +7182,12 @@ static int io_issue_sqe(struct io_kiocb *req, unsigned int issue_flags)
        case IORING_OP_SETXATTR:
                ret = io_setxattr(req, issue_flags);
                break;
+       case IORING_OP_FGETXATTR:
+               ret = io_fgetxattr(req, issue_flags);
+               break;
+       case IORING_OP_GETXATTR:
+               ret = io_getxattr(req, issue_flags);
+               break;
        default:
                ret = -EINVAL;
                break;

diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h
index c62a8bec8cd4199b38a8f3cb0367b6e401076b99..efc7ac9b3a6bfd1b032b3d80f7bb0effbdfe82cf 100644 (file)
--- a/include/uapi/linux/io_uring.h
+++ b/include/uapi/linux/io_uring.h
@@ -148,6 +148,8 @@ enum {
        IORING_OP_GETDENTS,
        IORING_OP_FSETXATTR,
        IORING_OP_SETXATTR,
+       IORING_OP_FGETXATTR,
+       IORING_OP_GETXATTR,
 
        /* this goes last, obviously */
        IORING_OP_LAST,