[LU-10923] cl_io_loop improperly assumes all ios are rw-type IOs

• Type: Bug
• Resolution: Won't Fix
• Priority: Minor
• Severity: 3
• Assignee: Dmitry Eremin (Inactive)
• Reporter: Oleg Drokin

Description

cl_io_loop has this code:

                pos   = io->u.ci_rw.rw_range.cir_pos;
                count = io->u.ci_rw.rw_range.cir_count;

                if (io->ci_pio) {
                        /* submit this range for parallel execution */
                        pt = cl_io_submit_pt(io, pos, count);
                        if (IS_ERR(pt)) {
                                cl_io_iter_fini(env, io);
                                rc = PTR_ERR(pt);
                                break;
                        }

                        *tail = pt;
                        tail = &pt->cip_next;
                } else {
                        size_t nob = io->ci_nob;

                        CDEBUG(D_VFSTRACE,
                                "execute type %u range: [%llu, %llu) nob: %zu %s\n",
                                io->ci_type, pos, pos + count, nob,
                                io->ci_continue ? "continue" : "stop");

Now the io->u.ci_rw. is only valid for accessing if the IO is of type CIT_READ/WRITE, otherwise the union is populated differently.

And cl_io_loop IS called by other places, for example:

        if (cl_io_init(env, io, CIT_FSYNC, io->ci_obj) == 0)
                result = cl_io_loop(env, io);

The problematic code was introduced by LU-8964 - parallel io code.
commit db59ecb5d1d0284fb918def6348a11e0966d7767

Issue Links

• is related to: LU-11825 Remove LU-8964/pio feature & supporting framework