io_uring: add support for ftruncate

Adds support for doing truncate through io_uring, eliminating
the need for applications to roll their own thread pool or offload
mechanism to be able to do non-blocking truncates.

Signed-off-by: Tony Solomonik <tony.solomonik@gmail.com>
Link: https://lore.kernel.org/r/20240202121724.17461-3-tony.solomonik@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h
index 7a673b52827b160afbd9d3b3bd64d3112dc7ce7c..fb812f1b6bb5a8f96002b56dcd690a1c739492c1 100644 (file)
--- a/include/uapi/linux/io_uring.h
+++ b/include/uapi/linux/io_uring.h
@@ -255,6 +255,7 @@ enum io_uring_op {
        IORING_OP_FUTEX_WAKE,
        IORING_OP_FUTEX_WAITV,
        IORING_OP_FIXED_FD_INSTALL,
+       IORING_OP_FTRUNCATE,
 
        /* this goes last, obviously */
        IORING_OP_LAST,

diff --git a/io_uring/Makefile b/io_uring/Makefile
index 2cdc51825405371a05e4357b0956799c6672431f..42afe4a1ff3182a580b7827b9be974dba62fa916 100644 (file)
--- a/io_uring/Makefile
+++ b/io_uring/Makefile
@@ -8,6 +8,6 @@ obj-$(CONFIG_IO_URING)          += io_uring.o xattr.o nop.o fs.o splice.o \
                                        statx.o net.o msg_ring.o timeout.o \
                                        sqpoll.o fdinfo.o tctx.o poll.o \
                                        cancel.o kbuf.o rsrc.o rw.o opdef.o \
-                                       notif.o waitid.o register.o
+                                       notif.o waitid.o register.o truncate.o
 obj-$(CONFIG_IO_WQ)            += io-wq.o
 obj-$(CONFIG_FUTEX)            += futex.o

diff --git a/io_uring/opdef.c b/io_uring/opdef.c
index b1ee3a9c38072933dd020848b7f3586af257d912..9c080aadc5a662f5fb9e8a15fd9a0f956405fb76 100644 (file)
--- a/io_uring/opdef.c
+++ b/io_uring/opdef.c
@@ -35,6 +35,7 @@
 #include "rw.h"
 #include "waitid.h"
 #include "futex.h"
+#include "truncate.h"
 
 static int io_no_issue(struct io_kiocb *req, unsigned int issue_flags)
 {
@@ -474,6 +475,12 @@ const struct io_issue_def io_issue_defs[] = {
                .prep                   = io_install_fixed_fd_prep,
                .issue                  = io_install_fixed_fd,
        },
+       [IORING_OP_FTRUNCATE] = {
+               .needs_file             = 1,
+               .hash_reg_file          = 1,
+               .prep                   = io_ftruncate_prep,
+               .issue                  = io_ftruncate,
+       },
 };
 
 const struct io_cold_def io_cold_defs[] = {
@@ -712,6 +719,9 @@ const struct io_cold_def io_cold_defs[] = {
        [IORING_OP_FIXED_FD_INSTALL] = {
                .name                   = "FIXED_FD_INSTALL",
        },
+       [IORING_OP_FTRUNCATE] = {
+               .name                   = "FTRUNCATE",
+       },
 };
 
 const char *io_uring_get_opcode(u8 opcode)

diff --git a/io_uring/truncate.c b/io_uring/truncate.c
new file mode 100644 (file)
index 0000000..62ee73d
--- /dev/null
+++ b/io_uring/truncate.c
@@ -0,0 +1,48 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/fs.h>
+#include <linux/file.h>
+#include <linux/mm.h>
+#include <linux/slab.h>
+#include <linux/syscalls.h>
+#include <linux/io_uring.h>
+
+#include <uapi/linux/io_uring.h>
+
+#include "../fs/internal.h"
+
+#include "io_uring.h"
+#include "truncate.h"
+
+struct io_ftrunc {
+       struct file                     *file;
+       loff_t                          len;
+};
+
+int io_ftruncate_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
+{
+       struct io_ftrunc *ft = io_kiocb_to_cmd(req, struct io_ftrunc);
+
+       if (sqe->rw_flags || sqe->addr || sqe->len || sqe->buf_index ||
+           sqe->splice_fd_in || sqe->addr3)
+               return -EINVAL;
+
+       ft->len = READ_ONCE(sqe->off);
+
+       req->flags |= REQ_F_FORCE_ASYNC;
+       return 0;
+}
+
+int io_ftruncate(struct io_kiocb *req, unsigned int issue_flags)
+{
+       struct io_ftrunc *ft = io_kiocb_to_cmd(req, struct io_ftrunc);
+       int ret;
+
+       WARN_ON_ONCE(issue_flags & IO_URING_F_NONBLOCK);
+
+       ret = do_ftruncate(req->file, ft->len, 1);
+
+       io_req_set_res(req, ret, 0);
+       return IOU_OK;
+}

diff --git a/io_uring/truncate.h b/io_uring/truncate.h
new file mode 100644 (file)
index 0000000..ec08829
--- /dev/null
+++ b/io_uring/truncate.h
@@ -0,0 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
+
+int io_ftruncate_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe);
+int io_ftruncate(struct io_kiocb *req, unsigned int issue_flags);