On Thu, Jan 27, 2022 at 12:02 AM Chaitanya Kulkarni <chaitanyak@xxxxxxxxxx> wrote: > > On 1/26/22 10:51 AM, Yang Shi wrote: > > External email: Use caution opening links or attachments > > > > > > Currently, rasdaemon uses the existing tracepoint block_rq_complete > > and filters out non-error cases in order to capture block disk errors. > > > > But there are a few problems with this approach: > > > > 1. Even kernel trace filter could do the filtering work, there is > > still some overhead after we enable this tracepoint. > > > > 2. The filter is merely based on errno, which does not align with kernel > > logic to check the errors for print_req_error(). > > > > 3. block_rq_complete only provides dev major and minor to identify > > the block device, it is not convenient to use in user-space. > > > > So introduce a new tracepoint block_rq_error just for the error case > > and provides the device name for convenience too. With this patch, > > rasdaemon could switch to block_rq_error. > > > > Cc: Jens Axboe <axboe@xxxxxxxxx> > > Cc: Christoph Hellwig <hch@xxxxxxxxxxxxx> > > Reviewed-by: Steven Rostedt <rostedt@xxxxxxxxxxx> > > Signed-off-by: Cong Wang <xiyou.wangcong@xxxxxxxxx> > > Signed-off-by: Yang Shi <shy828301@xxxxxxxxx> > > --- > > The v3 patch was submitted in Feb 2020, and Steven reviewed the patch, but > > it was not merged to upstream. See > > https://lore.kernel.org/lkml/20200203053650.8923-1-xiyou.wangcong@xxxxxxxxx/. > > > > The problems fixed by that patch still exist and we do need it to make > > disk error handling in rasdaemon easier. So this resurrected it and > > continued the version number. > > > > v4 --> v5: > > * Report the actual block layer status code instead of the errno per > > Christoph Hellwig. > > v3 --> v4: > > * Rebased to v5.17-rc1. > > * Collected reviewed-by tag from Steven. > > > > block/blk-mq.c | 4 +++- > > include/trace/events/block.h | 41 ++++++++++++++++++++++++++++++++++++ > > 2 files changed, 44 insertions(+), 1 deletion(-) > > > > diff --git a/block/blk-mq.c b/block/blk-mq.c > > index f3bf3358a3bb..4ca72ea917d4 100644 > > --- a/block/blk-mq.c > > +++ b/block/blk-mq.c > > @@ -789,8 +789,10 @@ bool blk_update_request(struct request *req, blk_status_t error, > > #endif > > > > if (unlikely(error && !blk_rq_is_passthrough(req) && > > - !(req->rq_flags & RQF_QUIET))) > > + !(req->rq_flags & RQF_QUIET))) { > > + trace_block_rq_error(req, error, nr_bytes); > > blk_print_req_error(req, error); > > + } > > > > blk_account_io_completion(req, nr_bytes); > > > > diff --git a/include/trace/events/block.h b/include/trace/events/block.h > > index 27170e40e8c9..918b190718d5 100644 > > --- a/include/trace/events/block.h > > +++ b/include/trace/events/block.h > > @@ -144,6 +144,47 @@ TRACE_EVENT(block_rq_complete, > > __entry->nr_sector, __entry->error) > > ); > > > > +/** > > + * block_rq_error - block IO operation error reported by device driver > > + * @rq: block operations request > > + * @error: status code > > + * @nr_bytes: number of completed bytes > > + * > > + * The block_rq_error tracepoint event indicates that some portion > > + * of operation request has failed as reported by the device driver. > > + */ > > +TRACE_EVENT(block_rq_error, > > + > > + TP_PROTO(struct request *rq, blk_status_t error, unsigned int nr_bytes), > > + > > + TP_ARGS(rq, error, nr_bytes), > > + > > + TP_STRUCT__entry( > > + __field( dev_t, dev ) > > + __string( name, rq->q->disk ? rq->q->disk->disk_name : "?") > > + __field( sector_t, sector ) > > + __field( unsigned int, nr_sector ) > > + __field( int, error ) > > + __array( char, rwbs, RWBS_LEN ) > > + ), > > + > > + TP_fast_assign( > > + __entry->dev = rq->q->disk ? disk_devt(rq->q->disk) : 0; > > + __assign_str(name, rq->q->disk ? rq->q->disk->disk_name : "?"); > > Did you verify that rq->q->disk NULL checks are must in this checkout > for blk_update_request() ? > > > + __entry->sector = blk_rq_pos(rq); > > + __entry->nr_sector = nr_bytes >> 9; > > + __entry->error = blk_status_to_errno(error); > > + > > + blk_fill_rwbs(__entry->rwbs, rq->cmd_flags); > > + ), > > + > > + TP_printk("%d,%d %s %s %llu + %u [%d]", > > + MAJOR(__entry->dev), MINOR(__entry->dev), > > + __get_str(name), __entry->rwbs, > > Since printing major number and minor number is sufficient to identify > the block device. We don't have a notion of printing disk_name for the > block tracepoints what makes this tracepoint special ? Thanks for the comments, will remove it to follow the convention. > > > + (unsigned long long)__entry->sector, > > + __entry->nr_sector, __entry->error) > > +); > > + > > DECLARE_EVENT_CLASS(block_rq, > > > > TP_PROTO(struct request *rq), > > -- > > 2.26.3 > > >
