diff options
| -rw-r--r-- | drivers/block/xen-blkback/blkback.c | 37 | ||||
| -rw-r--r-- | drivers/block/xen-blkback/common.h | 5 | ||||
| -rw-r--r-- | drivers/block/xen-blkback/xenbus.c | 18 |
3 files changed, 58 insertions, 2 deletions
diff --git a/drivers/block/xen-blkback/blkback.c b/drivers/block/xen-blkback/blkback.c index e0dab614049..184b1335c8e 100644 --- a/drivers/block/xen-blkback/blkback.c +++ b/drivers/block/xen-blkback/blkback.c @@ -452,6 +452,23 @@ static void xen_blk_discard(struct xen_blkif *blkif, struct blkif_request *req) make_response(blkif, req->id, req->operation, status); } +static void xen_blk_drain_io(struct xen_blkif *blkif) +{ + atomic_set(&blkif->drain, 1); + do { + wait_for_completion_interruptible_timeout( + &blkif->drain_complete, HZ); + + if (!atomic_read(&blkif->drain)) + break; + /* The initial value is one, and one refcnt taken at the + * start of the xen_blkif_schedule thread. */ + if (atomic_read(&blkif->refcnt) <= 2) + break; + } while (!kthread_should_stop()); + atomic_set(&blkif->drain, 0); +} + /* * Completion callback on the bio's. Called as bh->b_end_io() */ @@ -464,6 +481,11 @@ static void __end_block_io_op(struct pending_req *pending_req, int error) pr_debug(DRV_PFX "flush diskcache op failed, not supported\n"); xen_blkbk_flush_diskcache(XBT_NIL, pending_req->blkif->be, 0); pending_req->status = BLKIF_RSP_EOPNOTSUPP; + } else if ((pending_req->operation == BLKIF_OP_WRITE_BARRIER) && + (error == -EOPNOTSUPP)) { + pr_debug(DRV_PFX "write barrier op failed, not supported\n"); + xen_blkbk_barrier(XBT_NIL, pending_req->blkif->be, 0); + pending_req->status = BLKIF_RSP_EOPNOTSUPP; } else if (error) { pr_debug(DRV_PFX "Buffer not up-to-date at end of operation," " error=%d\n", error); @@ -481,6 +503,10 @@ static void __end_block_io_op(struct pending_req *pending_req, int error) pending_req->operation, pending_req->status); xen_blkif_put(pending_req->blkif); free_req(pending_req); + if (atomic_read(&pending_req->blkif->refcnt) <= 2) { + if (atomic_read(&pending_req->blkif->drain)) + complete(&pending_req->blkif->drain_complete); + } } } @@ -574,7 +600,6 @@ do_block_io_op(struct xen_blkif *blkif) return more_to_do; } - /* * Transmutation of the 'struct blkif_request' to a proper 'struct bio' * and call the 'submit_bio' to pass it to the underlying storage. @@ -591,6 +616,7 @@ static int dispatch_rw_block_io(struct xen_blkif *blkif, int i, nbio = 0; int operation; struct blk_plug plug; + bool drain = false; switch (req->operation) { case BLKIF_OP_READ: @@ -601,6 +627,8 @@ static int dispatch_rw_block_io(struct xen_blkif *blkif, blkif->st_wr_req++; operation = WRITE_ODIRECT; break; + case BLKIF_OP_WRITE_BARRIER: + drain = true; case BLKIF_OP_FLUSH_DISKCACHE: blkif->st_f_req++; operation = WRITE_FLUSH; @@ -609,7 +637,6 @@ static int dispatch_rw_block_io(struct xen_blkif *blkif, blkif->st_ds_req++; operation = REQ_DISCARD; break; - case BLKIF_OP_WRITE_BARRIER: default: operation = 0; /* make gcc happy */ goto fail_response; @@ -668,6 +695,12 @@ static int dispatch_rw_block_io(struct xen_blkif *blkif, } } + /* Wait on all outstanding I/O's and once that has been completed + * issue the WRITE_FLUSH. + */ + if (drain) + xen_blk_drain_io(pending_req->blkif); + /* * If we have failed at this point, we need to undo the M2P override, * set gnttab_set_unmap_op on all of the grant references and perform diff --git a/drivers/block/xen-blkback/common.h b/drivers/block/xen-blkback/common.h index 1b1bc445868..e638457d9de 100644 --- a/drivers/block/xen-blkback/common.h +++ b/drivers/block/xen-blkback/common.h @@ -181,6 +181,9 @@ struct xen_blkif { atomic_t refcnt; wait_queue_head_t wq; + /* for barrier (drain) requests */ + struct completion drain_complete; + atomic_t drain; /* One thread per one blkif. */ struct task_struct *xenblkd; unsigned int waiting_reqs; @@ -229,6 +232,8 @@ int xen_blkif_schedule(void *arg); int xen_blkbk_flush_diskcache(struct xenbus_transaction xbt, struct backend_info *be, int state); +int xen_blkbk_barrier(struct xenbus_transaction xbt, + struct backend_info *be, int state); struct xenbus_device *xen_blkbk_xenbus(struct backend_info *be); static inline void blkif_get_x86_32_req(struct blkif_request *dst, diff --git a/drivers/block/xen-blkback/xenbus.c b/drivers/block/xen-blkback/xenbus.c index 1c44b325413..a6d43030b10 100644 --- a/drivers/block/xen-blkback/xenbus.c +++ b/drivers/block/xen-blkback/xenbus.c @@ -114,6 +114,8 @@ static struct xen_blkif *xen_blkif_alloc(domid_t domid) spin_lock_init(&blkif->blk_ring_lock); atomic_set(&blkif->refcnt, 1); init_waitqueue_head(&blkif->wq); + init_completion(&blkif->drain_complete); + atomic_set(&blkif->drain, 0); blkif->st_print = jiffies; init_waitqueue_head(&blkif->waiting_to_free); @@ -474,6 +476,19 @@ kfree: out: return err; } +int xen_blkbk_barrier(struct xenbus_transaction xbt, + struct backend_info *be, int state) +{ + struct xenbus_device *dev = be->dev; + int err; + + err = xenbus_printf(xbt, dev->nodename, "feature-barrier", + "%d", state); + if (err) + xenbus_dev_fatal(dev, err, "writing feature-barrier"); + + return err; +} /* * Entry point to this code when a new device is created. Allocate the basic @@ -708,6 +723,9 @@ again: err = xen_blkbk_discard(xbt, be); + /* If we can't advertise it is OK. */ + err = xen_blkbk_barrier(xbt, be, be->blkif->vbd.flush_support); + err = xenbus_printf(xbt, dev->nodename, "sectors", "%llu", (unsigned long long)vbd_sz(&be->blkif->vbd)); if (err) { |