io_uring/rw: ensure kiocb_end_write() is always called

A previous commit moved the notifications and end-write handling, but
it is now missing a few spots where we also want to call both of those.
Without that, we can potentially be missing file notifications, and
more importantly, have an imbalance in the super_block writers sem
accounting.

Fixes: b000145e9907 ("io_uring/rw: defer fsnotify calls to task context")
Reported-by: Dave Chinner <david@fromorbit.com>
Link: https://lore.kernel.org/all/20221010050319.GC2703033@dread.disaster.area/
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/io_uring/rw.c b/io_uring/rw.c
index 453e0ae921609f4c708cdcf5ac31fe1781ee5b33..100de2626e4788bd2e5ebdd6ee1c8556a6432b44 100644 (file)
--- a/io_uring/rw.c
+++ b/io_uring/rw.c
@@ -234,11 +234,34 @@ static void kiocb_end_write(struct io_kiocb *req)
        }
 }
 
+/*
+ * Trigger the notifications after having done some IO, and finish the write
+ * accounting, if any.
+ */
+static void io_req_io_end(struct io_kiocb *req)
+{
+       struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw);
+
+       WARN_ON(!in_task());
+
+       if (rw->kiocb.ki_flags & IOCB_WRITE) {
+               kiocb_end_write(req);
+               fsnotify_modify(req->file);
+       } else {
+               fsnotify_access(req->file);
+       }
+}
+
 static bool __io_complete_rw_common(struct io_kiocb *req, long res)
 {
        if (unlikely(res != req->cqe.res)) {
                if ((res == -EAGAIN || res == -EOPNOTSUPP) &&
                    io_rw_should_reissue(req)) {
+                       /*
+                        * Reissue will start accounting again, finish the
+                        * current cycle.
+                        */
+                       io_req_io_end(req);
                        req->flags |= REQ_F_REISSUE | REQ_F_PARTIAL_IO;
                        return true;
                }
@@ -264,15 +287,7 @@ static inline int io_fixup_rw_res(struct io_kiocb *req, long res)
 
 static void io_req_rw_complete(struct io_kiocb *req, bool *locked)
 {
-       struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw);
-
-       if (rw->kiocb.ki_flags & IOCB_WRITE) {
-               kiocb_end_write(req);
-               fsnotify_modify(req->file);
-       } else {
-               fsnotify_access(req->file);
-       }
-
+       io_req_io_end(req);
        io_req_task_complete(req, locked);
 }
 
@@ -317,6 +332,11 @@ static int kiocb_done(struct io_kiocb *req, ssize_t ret,
                req->file->f_pos = rw->kiocb.ki_pos;
        if (ret >= 0 && (rw->kiocb.ki_complete == io_complete_rw)) {
                if (!__io_complete_rw_common(req, ret)) {
+                       /*
+                        * Safe to call io_end from here as we're inline
+                        * from the submission path.
+                        */
+                       io_req_io_end(req);
                        io_req_set_res(req, final_ret,
                                       io_put_kbuf(req, issue_flags));
                        return IOU_OK;