if (debug_lvl)
printk(KERN_DEBUG "%s: started\n", current->comm);
- while (!kthread_should_stop()) {
+ while (!blkif->remove_requested) {
if (try_to_freeze())
continue;
wait_event_interruptible(
blkif->wq,
- blkif->waiting_reqs || kthread_should_stop());
+ blkif->waiting_reqs || blkif->remove_requested);
wait_event_interruptible(
pending_free_wq,
- !list_empty(&pending_free) || kthread_should_stop());
+ !list_empty(&pending_free) || blkif->remove_requested);
blkif->waiting_reqs = 0;
smp_mb(); /* clear flag *before* checking for work */
if (debug_lvl)
printk(KERN_DEBUG "%s: exiting\n", current->comm);
- blkif->xenblkd = NULL;
blkif_put(blkif);
+ blkback_close(blkif);
return 0;
}
break;
}
- if (kthread_should_stop()) {
+ if (blkif->remove_requested) {
more_to_do = 1;
break;
}
pr_debug("(file=%s, line=%d) " _f, \
__FILE__ , __LINE__ , ## _a )
+#define WPRINTK(fmt, args...) printk(KERN_WARNING "blk_tap: " fmt, ##args)
+
struct vbd {
blkif_vdev_t handle; /* what the domain refers to this vbd as */
unsigned char readonly; /* Non-zero -> read-only */
/* Back pointer to the backend_info. */
struct backend_info *be;
/* Private fields. */
+ int remove_requested;
spinlock_t blk_ring_lock;
atomic_t refcnt;
int vbd_create(blkif_t *blkif, blkif_vdev_t vdevice, unsigned major,
unsigned minor, int readonly, int cdrom);
void vbd_free(struct vbd *vbd);
+void vbd_sync(struct vbd *vbd);
unsigned long long vbd_size(struct vbd *vbd);
unsigned int vbd_info(struct vbd *vbd);
int blkback_barrier(struct xenbus_transaction xbt,
struct backend_info *be, int state);
+void blkback_close(blkif_t *blkif);
+
#endif /* __BLKIF__BACKEND__COMMON_H__ */
void blkif_disconnect(blkif_t *blkif)
{
- if (blkif->xenblkd) {
- kthread_stop(blkif->xenblkd);
- blkif->xenblkd = NULL;
- }
-
atomic_dec(&blkif->refcnt);
wait_event(blkif->waiting_to_free, atomic_read(&blkif->refcnt) == 0);
atomic_inc(&blkif->refcnt);
vbd->bdev = NULL;
}
+void vbd_sync(struct vbd *vbd)
+{
+ if (vbd->bdev)
+ fsync_bdev(vbd->bdev);
+}
+
int vbd_translate(struct phys_req *req, blkif_t *blkif, int operation)
{
struct vbd *vbd = &blkif->vbd;
struct xenbus_device *dev;
blkif_t *blkif;
struct xenbus_watch backend_watch;
+ struct xenbus_watch shutdown_watch;
unsigned major;
unsigned minor;
char *mode;
+ int group_added;
+ char *nodename;
+ atomic_t refcnt;
+ pid_t kthread_pid;
+ int shutdown_signalled;
};
+DECLARE_MUTEX(blkback_dev_sem);
+
static void connect(struct backend_info *);
static int connect_ring(struct backend_info *);
static void backend_changed(struct xenbus_watch *, const char **,
xenbus_dev_error(blkif->be->dev, err, "start xenblkd");
return;
}
+
+ blkif->be->kthread_pid = blkif->xenblkd->pid;
+ atomic_inc(&blkif->be->refcnt);
err = xenbus_printf(XBT_NIL, blkif->be->dev->nodename, "kthread-pid",
"%d", blkif->xenblkd->pid);
int xenvbd_sysfs_addif(struct xenbus_device *dev)
{
int error;
+ struct backend_info *be = dev->dev.driver_data;
error = device_create_file(&dev->dev, &dev_attr_physical_device);
if (error)
if (error)
goto fail3;
+ be->group_added = 1;
+
return 0;
fail3: sysfs_remove_group(&dev->dev.kobj, &vbdstat_group);
void xenvbd_sysfs_delif(struct xenbus_device *dev)
{
+ struct backend_info *be = dev->dev.driver_data;
+ if (be->group_added == 0)
+ return;
sysfs_remove_group(&dev->dev.kobj, &vbdstat_group);
device_remove_file(&dev->dev, &dev_attr_mode);
device_remove_file(&dev->dev, &dev_attr_physical_device);
+ be->group_added = 0;
+}
+
+static int kthread_remove(struct backend_info *be)
+{
+ blkif_t *blkif = be->blkif;
+
+ if (!blkif || !blkif->xenblkd)
+ return 0;
+
+ blkif->remove_requested = 1;
+ wake_up_process(blkif->xenblkd);
+
+ return -EBUSY;
+}
+
+static void signal_shutdown(struct backend_info *be)
+{
+ int err;
+
+ down(&blkback_dev_sem);
+
+ if (be->shutdown_signalled)
+ goto out;
+
+ err = xenbus_write(XBT_NIL, be->nodename, "shutdown-done", "");
+ if (err)
+ WPRINTK("Error writing shutdown-done for %s: %d\n",
+ be->nodename, err);
+
+ if (be->dev)
+ xenbus_switch_state(be->dev, XenbusStateClosed);
+
+ be->shutdown_signalled = 1;
+
+ out:
+ up(&blkback_dev_sem);
+}
+
+static void backend_release(struct backend_info *be)
+{
+ blkif_t *blkif = be->blkif;
+
+ if (current->pid == be->kthread_pid)
+ signal_shutdown(be);
+
+ if (!atomic_dec_and_test(&be->refcnt))
+ return;
+
+ signal_shutdown(be);
+
+ if (blkif) {
+ blkif_disconnect(blkif);
+ vbd_free(&blkif->vbd);
+ blkif_free(blkif);
+ be->blkif = NULL;
+ }
+
+ kfree(be->nodename);
+ kfree(be);
}
static int blkback_remove(struct xenbus_device *dev)
{
struct backend_info *be = dev->dev.driver_data;
- DPRINTK("");
-
- if (be->major || be->minor)
- xenvbd_sysfs_delif(dev);
+ down(&blkback_dev_sem);
+ be->dev = NULL;
+ up(&blkback_dev_sem);
if (be->backend_watch.node) {
unregister_xenbus_watch(&be->backend_watch);
be->backend_watch.node = NULL;
}
- if (be->blkif) {
- blkif_disconnect(be->blkif);
- vbd_free(&be->blkif->vbd);
- blkif_free(be->blkif);
- be->blkif = NULL;
+ if (be->shutdown_watch.node) {
+ unregister_xenbus_watch(&be->shutdown_watch);
+ kfree(be->shutdown_watch.node);
+ be->shutdown_watch.node = NULL;
}
- kfree(be);
+ if (kthread_remove(be))
+ WPRINTK("BAD REMOVE REQUEST for %s\n", be->nodename);
+
+ xenvbd_sysfs_delif(dev);
+ backend_release(be);
+
dev->dev.driver_data = NULL;
+
return 0;
}
+/*
+ * called by kthread when closing
+ */
+void blkback_close(blkif_t *blkif)
+{
+ blkif_disconnect(blkif);
+ vbd_sync(&blkif->vbd);
+ blkif->remove_requested = 0;
+
+ down(&blkback_dev_sem);
+ if (blkif->be->dev)
+ xenvbd_sysfs_delif(blkif->be->dev);
+ up(&blkback_dev_sem);
+
+ backend_release(blkif->be);
+ blkif->xenblkd = NULL;
+}
+
+static void start_shutdown(struct xenbus_watch *watch,
+ const char **vec, unsigned int length)
+{
+ int err;
+ char *type;
+ unsigned int len;
+ struct backend_info *be
+ = container_of(watch, struct backend_info, shutdown_watch);
+ struct xenbus_device *dev = be->dev;
+
+ if (be->shutdown_signalled)
+ return;
+
+ type = xenbus_read(XBT_NIL, dev->nodename, "shutdown-request", &len);
+ err = (IS_ERR(type) ? PTR_ERR(type) : 0);
+
+ if (XENBUS_EXIST_ERR(err))
+ return;
+
+ if (err) {
+ xenbus_dev_fatal(dev, err, "reading shutdown-request");
+ return;
+ }
+
+ xenbus_switch_state(dev, XenbusStateClosing);
+
+ if (len == sizeof("force") - 1 && !memcmp(type, "force", len))
+ if (!kthread_remove(be))
+ signal_shutdown(be); /* shutdown immediately */
+
+ kfree(type);
+}
+
int blkback_barrier(struct xenbus_transaction xbt,
struct backend_info *be, int state)
{
}
be->dev = dev;
dev->dev.driver_data = be;
+ atomic_set(&be->refcnt, 1);
+
+ be->nodename = kasprintf(GFP_KERNEL, "%s", dev->nodename);
+ if (!be->nodename) {
+ xenbus_dev_fatal(dev, -ENOMEM,
+ "allocating backend structure");
+ kfree(be);
+ return -ENOMEM;
+ }
be->blkif = blkif_alloc(dev->otherend_id);
if (IS_ERR(be->blkif)) {
if (err)
goto fail;
+ err = xenbus_watch_path2(dev, dev->nodename, "shutdown-request",
+ &be->shutdown_watch, start_shutdown);
+ if (err)
+ goto fail;
+
err = xenbus_switch_state(dev, XenbusStateInitWait);
if (err)
goto fail;
struct backend_info *be = dev->dev.driver_data;
int err;
- DPRINTK("%s", xenbus_strstate(frontend_state));
+ DPRINTK("%s: %s", dev->nodename, xenbus_strstate(frontend_state));
switch (frontend_state) {
case XenbusStateInitialising:
if (dev->state == XenbusStateClosed) {
printk(KERN_INFO "%s: %s: prepare for reconnect\n",
__FUNCTION__, dev->nodename);
+
+ xenbus_rm(XBT_NIL, dev->nodename, "shutdown-done");
+ be->shutdown_signalled = 0;
+
xenbus_switch_state(dev, XenbusStateInitWait);
}
break;
break;
case XenbusStateClosing:
- blkif_disconnect(be->blkif);
xenbus_switch_state(dev, XenbusStateClosing);
break;
case XenbusStateClosed:
- xenbus_switch_state(dev, XenbusStateClosed);
- if (xenbus_dev_is_online(dev))
- break;
- /* fall through if not online */
+ if (!kthread_remove(be))
+ signal_shutdown(be);
+ break;
+
case XenbusStateUnknown:
device_unregister(&dev->dev);
break;
frontend_state);
break;
}
+
+ DPRINTK("%s: %s", dev->nodename, xenbus_strstate(dev->state));
}
struct blkfront_info *info = dev->dev.driver_data;
struct block_device *bd;
- DPRINTK("blkfront:backend_changed.\n");
+ DPRINTK("%s: %s\n", dev->nodename,
+ xenbus_strstate(backend_state));
switch (backend_state) {
case XenbusStateInitialising:
int ret, i;
spin_lock_irq(&backdev_io_lock);
+
+ if (!info->idx_map)
+ goto start_queue;
+
for (usr_idx = 0; usr_idx < MAX_PENDING_REQS; usr_idx++) {
if (info->idx_map[usr_idx] == INVALID_REQ)
continue;
mmap_idx = ID_TO_MIDX(info->idx_map[usr_idx]);
pending_req = &pending_reqs[mmap_idx][pending_idx];
blkif_put(info->blkif);
+ WPRINTK("failing %s of %d pages pending on close\n",
+ (pending_req->operation == BLKIF_OP_READ ?
+ "read" : "write"), pending_req->nr_pages);
if (pending_req->inuse != 2)
continue;
for (i = 0; i < pending_req->nr_pages; i++)
umap_uaddr(&init_mm, idx_to_kaddr(mmap_idx,
pending_idx, i));
req = (struct request *)(unsigned long)pending_req->id;
- /* See NOTE in do_backdev_request. */
- ret = end_that_request_first(req, 1, req->hard_nr_sectors);
+ ret = end_that_request_first(req, 0, req->hard_nr_sectors);
BUG_ON(ret);
- end_that_request_last(req, 1);
+ end_that_request_last(req, 0);
}
+
+ start_queue:
if (info->backdev) {
info->backdev->gd->queue->queuedata = NULL;
blk_start_queue(info->backdev->gd->queue);
}
+
spin_unlock_irq(&backdev_io_lock);
}
blk_cleanup_queue(info->gd->queue);
if (uinfo->blkif->xenblkd)
- wake_up_process(uinfo->blkif->xenblkd);
+ wake_up_process(uinfo->blkif->xenblkd);
blkif_put(uinfo->blkif);
pte_t *ptep, struct page *pmd_page, unsigned long addr, void *data)
{
struct mm_struct *mm = (struct mm_struct *)data;
-
+
DPRINTK("unmap_uaddr ptep %p\n", ptep);
pte_clear(mm, addr, ptep);
xen_invlpg(addr);
end_request(req, 0);
continue;
}
+
+#if 0
if (uinfo->remove_requested) {
DPRINTK("device no longer in use %d\n", info->uinfo->minor);
end_request(req, 0);
continue;
}
+#endif
if (RING_FULL(&uinfo->ufe_ring)) {
wait:
info = rq->queuedata;
if (info == NULL || info->uinfo == NULL ||
info->uinfo->remove_requested) {
- /* NOTE: we pretend that the request succeeded because
- * this seems better than returning block device
- * errors to dom0 given that the linux filesystem code
- * doesn't seem to handle these too gracefully. */
- while ((req = elv_next_request(rq)))
- end_request(req, 1);
+ while ((req = elv_next_request(rq))) {
+ WPRINTK("backdev closed: failing secs %llu - %llu\n",
+ req->sector, req->sector + req->nr_sectors);
+ end_request(req, 0);
+ }
return;
}
info->uinfo->blkif->waiting_reqs = 1;
return;
}
+int
+backdev_setup(struct tap_blkif *uinfo)
+{
+ int ret;
+ unsigned long domid, busid;
+
+ if (!uinfo->trans.domid && !uinfo->trans.busid)
+ return -EINVAL;
+
+ domid = uinfo->trans.domid;
+ busid = uinfo->trans.busid;
+
+ while (backend_device_linked(domid, busid) &&
+ uinfo->backdev == NULL && uinfo->dev_inuse &&
+ uinfo->trans.domid == domid && uinfo->trans.busid == busid) {
+
+ ret = wait_event_interruptible(backdev_setup_wq,
+ uinfo->backdev ||
+ uinfo->dev_inuse == 0 ||
+ uinfo->trans.domid != domid ||
+ uinfo->trans.busid != busid ||
+ !backend_device_linked(domid,
+ busid));
+ if (ret)
+ return ret;
+ }
+
+ if (!backend_device_linked(domid, busid) || uinfo->dev_inuse == 0 ||
+ uinfo->trans.domid != domid || uinfo->trans.busid != busid)
+ return -EINVAL;
+
+ return 0;
+}
+
int
create_backdev(struct tap_blkif *uinfo)
{
extern int register_backdev(void);
extern int create_backdev(struct tap_blkif *);
extern int destroy_backdev(struct tap_blkif *);
+extern int backdev_setup(struct tap_blkif *);
extern void backdev_finish_req(struct tap_blkif *, int, blkif_response_t *,
struct pending_req *);
extern void backdev_restart_queue(struct tap_blkif *);
#include <linux/delay.h>
#include <linux/nsproxy.h>
#include <asm/tlbflush.h>
-#include <linux/syscalls.h>
#include "blktap.h"
#include "backdev.h"
info->vma = NULL;
clear_bit(2, &info->dev_inuse);
- if (info->blkif->xenblkd)
+ if (info->blkif && info->blkif->xenblkd)
wake_up_process(info->blkif->xenblkd);
up_write(&info->vm_update_sem);
}
out:
+ if (info)
+ info->blkif = NULL;
return info;
}
return NULL;
}
+void disassociate_blkif(domid_t domid, int xenbus_id)
+{
+ int i;
+ tap_blkif_t *info;
+
+ for (i = 1; i < MAX_TAP_DEV; i++) {
+ info = tapfds[i];
+ if (info && info->trans.domid == domid &&
+ info->trans.busid == xenbus_id) {
+ info->trans.busid = 0;
+ info->trans.domid = 0;
+ clear_bit(0, &info->dev_inuse);
+ wake_up(&backdev_setup_wq);
+ return;
+ }
+ }
+}
+
static int blktap_open(struct inode *inode, struct file *filp)
{
int idx = iminor(inode) - BLKTAP_MINOR;
DPRINTK("Opening device /dev/xen/blktap%d\n", idx);
/* Only one process can access device at a time */
- if (test_and_set_bit(1, &info->dev_inuse))
+ if (!test_bit(0, &info->dev_inuse) ||
+ test_and_set_bit(1, &info->dev_inuse))
return -EBUSY;
clear_bit(0, &info->dev_inuse);
DPRINTK("Freeing device [/dev/xen/blktap%d]\n",info->minor);
clear_bit(1, &info->dev_inuse);
+ wake_up(&backdev_setup_wq);
filp->private_data = NULL;
return -EINVAL;
clear_bit(0, &tapfds[dev]->dev_inuse);
+ wake_up(&backdev_setup_wq);
return 0;
}
case BLKTAP_IOCTL_BACKDEV_SETUP:
{
unsigned long dev = arg;
- int ret;
DPRINTK("BLKTAP_IOCTL_BACKDEV_SETUP ioctl: %ld\n", dev);
if (dev > MAX_TAP_DEV || tapfds[dev] == NULL)
return -EINVAL;
-
- while (tapfds[dev]->backdev == NULL) {
- ret = wait_event_interruptible(backdev_setup_wq,
- tapfds[dev]->backdev);
- if (ret)
- return ret;
- }
- return 0;
+
+ return backdev_setup(tapfds[dev]);
}
}
void blktap_kick_user(struct tap_blkif *info)
{
-
wake_up_interruptible(&info->wait);
}
}
offset = (uvaddr - info->vma->vm_start) >> PAGE_SHIFT;
- ClearPageReserved(map[offset]);
+ if (map[offset])
+ ClearPageReserved(map[offset]);
map[offset] = NULL;
BLKTAP_INVALIDATE_HANDLE(khandle);
backdev_restart_queue(info);
if (info->remove_requested && backdev_users(info) == 0) {
- sys_kill(info->pid, SIGTERM);
+ signal_tapdisk(blkif->be);
info->remove_requested = 0;
}
kfree(info->idx_map);
info->idx_map = NULL;
- tap_blkif_free(blkif);
- blkif->xenblkd = NULL;
-
+ blkif_put(blkif);
+ blktap_close(blkif);
+
clear_bit(3, &info->dev_inuse);
info->remove_requested = 0;
break;
}
- if (kthread_should_stop()) {
+ if (info->remove_requested) {
more_to_do = 1;
break;
}
void blktap_kick_user(struct tap_blkif *info);
+int backend_device_linked(unsigned long domid, unsigned long busid);
+
extern wait_queue_head_t backdev_setup_wq;
void tap_blkif_free(blkif_t *blkif);
int tap_blkif_map(blkif_t *blkif, unsigned long shared_page,
unsigned int evtchn);
-void tap_blkif_unmap(blkif_t *blkif);
+void tap_blkif_disconnect(blkif_t *blkif);
int tap_blkif_connected(blkif_t *blkif);
#define blkif_get(_b) (atomic_inc(&(_b)->refcnt))
struct tap_blkif *associate_blkif(domid_t domid, int xenbus_id,
blkif_t *blkif);
-void signal_tapdisk(int idx);
+void disassociate_blkif(domid_t domid, int xenbus_id);
+
+int signal_tapdisk(struct backend_info *be);
+
+void blktap_close(blkif_t *blkif);
void tap_blkif_notify_work(blkif_t *blkif);
return 0;
}
-void tap_blkif_unmap(blkif_t *blkif)
+void tap_blkif_disconnect(blkif_t *blkif)
{
+ atomic_dec(&blkif->refcnt);
+ wait_event(blkif->waiting_to_free, atomic_read(&blkif->refcnt) == 0);
+ atomic_inc(&blkif->refcnt);
+
if (blkif->irq) {
unbind_from_irqhandler(blkif->irq, blkif);
blkif->irq = 0;
void tap_blkif_free(blkif_t *blkif)
{
- atomic_dec(&blkif->refcnt);
- wait_event(blkif->waiting_to_free, atomic_read(&blkif->refcnt) == 0);
-
- tap_blkif_unmap(blkif);
+ if (!atomic_dec_and_test(&blkif->refcnt))
+ BUG();
kmem_cache_free(blkif_cachep, blkif);
}
#include <stdarg.h>
#include <linux/module.h>
#include <linux/kthread.h>
+#include <linux/list.h>
#include <xen/xenbus.h>
#include "common.h"
#include "blktap.h"
-
struct backend_info
{
struct xenbus_device *dev;
blkif_t *blkif;
struct xenbus_watch backend_watch;
+ struct xenbus_watch shutdown_watch;
int xenbus_id;
+ int dom_id;
int group_added;
+ char *nodename;
+ atomic_t refcnt;
+ pid_t kthread_pid;
+ int shutdown_signalled;
+ struct list_head list;
};
+DECLARE_MUTEX(blktap_dev_sem);
+LIST_HEAD(backend_devices);
static void connect(struct backend_info *);
static int connect_ring(struct backend_info *);
static void tap_frontend_changed(struct xenbus_device *dev,
enum xenbus_state frontend_state);
+static void
+link_backend_device(struct backend_info *be)
+{
+ down(&blktap_dev_sem);
+ list_add(&be->list, &backend_devices);
+ up(&blktap_dev_sem);
+ wake_up(&backdev_setup_wq);
+}
+
+static void
+unlink_backend_device(struct backend_info *be)
+{
+ down(&blktap_dev_sem);
+ list_del(&be->list);
+ up(&blktap_dev_sem);
+ wake_up(&backdev_setup_wq);
+}
+
+int
+backend_device_linked(unsigned long domid, unsigned long busid)
+{
+ int linked = 0;
+ struct backend_info *b;
+
+ down(&blktap_dev_sem);
+ list_for_each_entry(b, &backend_devices, list) {
+ if (b->dom_id == domid && b->xenbus_id == busid) {
+ linked = 1;
+ break;
+ }
+ }
+ up(&blktap_dev_sem);
+
+ return linked;
+}
+
static int strsep_len(const char *str, char c, unsigned int len)
{
unsigned int i;
DPRINTK("Get_id called for %s (%s)\n",str,num);
return simple_strtol(num, NULL, 10);
+}
+
+static long get_dom_id(const char *str)
+{
+ int start, end;
+ const char *ptr;
+ char *tptr, num[25];
+
+ start = strsep_len(str, '/', 1);
+ end = strsep_len(str, '/', 2);
+ if (start < 0 || end < 0)
+ return -1;
+
+ ptr = str + start + 1;
+ strncpy(num, ptr, end - start);
+ tptr = num + (end - (start + 1));
+ *tptr = '\0';
+
+ return simple_strtol(num, NULL, 10);
}
static int blktap_name(blkif_t *blkif, char *buf)
.attrs = tapstat_attrs,
};
-int xentap_sysfs_addif(struct xenbus_device *dev)
+static int xentap_sysfs_addif(struct xenbus_device *dev)
{
int err;
struct backend_info *be = dev->dev.driver_data;
return err;
}
-void xentap_sysfs_delif(struct xenbus_device *dev)
+static void xentap_sysfs_delif(struct xenbus_device *dev)
{
struct backend_info *be = dev->dev.driver_data;
+ if (be->group_added == 0)
+ return;
sysfs_remove_group(&dev->dev.kobj, &tapstat_group);
be->group_added = 0;
}
+static int kthread_remove(struct backend_info *be)
+{
+ blkif_t *blkif = be->blkif;
+
+ if (!blkif || !blkif->xenblkd)
+ return 0;
+
+ blkif->tapif->remove_requested = 1;
+ wake_up_process(blkif->xenblkd);
+
+ return -EBUSY;
+}
+
+static void signal_shutdown(struct backend_info *be)
+{
+ int err;
+
+ down(&blktap_dev_sem);
+
+ if (be->shutdown_signalled)
+ goto out;
+
+ if (be->blkif)
+ disassociate_blkif(be->blkif->domid, be->xenbus_id);
+
+ err = xenbus_write(XBT_NIL, be->nodename, "shutdown-done", "");
+ if (err)
+ WPRINTK("Error writing shutdown-done for %s: %d\n",
+ be->nodename, err);
+
+ if (be->dev)
+ xenbus_switch_state(be->dev, XenbusStateClosed);
+
+ be->shutdown_signalled = 1;
+
+ out:
+ up(&blktap_dev_sem);
+}
+
+static void backend_release(struct backend_info *be)
+{
+ blkif_t *blkif = be->blkif;
+
+ if (current->pid == be->kthread_pid)
+ signal_shutdown(be);
+
+ if (!atomic_dec_and_test(&be->refcnt))
+ return;
+
+ signal_shutdown(be);
+
+ if (blkif) {
+ tap_blkif_disconnect(blkif);
+ tap_blkif_free(blkif);
+ be->blkif = NULL;
+ }
+
+ kfree(be->nodename);
+ kfree(be);
+}
+
static int blktap_remove(struct xenbus_device *dev)
{
struct backend_info *be = dev->dev.driver_data;
- if (be->group_added)
- xentap_sysfs_delif(be->dev);
+ down(&blktap_dev_sem);
+ be->dev = NULL;
+ up(&blktap_dev_sem);
+
+ unlink_backend_device(be);
+
if (be->backend_watch.node) {
unregister_xenbus_watch(&be->backend_watch);
kfree(be->backend_watch.node);
+ be->backend_watch.node = NULL;
}
- if (be->blkif) {
- if (be->blkif->xenblkd == NULL) {
- if (atomic_read(&be->blkif->refcnt) != 1)
- WPRINTK("refcnt is %d, expected 1",
- atomic_read(&be->blkif->refcnt));
- /* If the kthread was never started, free tap_blkif. */
- tap_blkif_free(be->blkif);
- } else {
- struct tap_blkif *info = be->blkif->tapif;
-
- down_write(&info->vm_update_sem);
- tap_blkif_unmap(be->blkif);
- be->blkif->be = NULL;
- up_write(&info->vm_update_sem);
-
- be->blkif->tapif->remove_requested = 1;
- wake_up_process(be->blkif->xenblkd);
- blkif_put(be->blkif);
- }
+
+ if (be->shutdown_watch.node) {
+ unregister_xenbus_watch(&be->shutdown_watch);
+ kfree(be->shutdown_watch.node);
+ be->shutdown_watch.node = NULL;
}
- be->blkif->be = NULL;
- kfree(be);
+
+ if (kthread_remove(be))
+ WPRINTK("BAD REMOVE REQUEST for %s\n", be->nodename);
+
+ xentap_sysfs_delif(dev);
+ backend_release(be);
+
dev->dev.driver_data = NULL;
+
return 0;
}
+/*
+ * called by kthread when closing
+ */
+void blktap_close(blkif_t *blkif)
+{
+ tap_blkif_disconnect(blkif);
+ blkif->tapif->remove_requested = 0;
+
+ down(&blktap_dev_sem);
+ if (blkif->be->dev)
+ xentap_sysfs_delif(blkif->be->dev);
+ up(&blktap_dev_sem);
+
+ backend_release(blkif->be);
+ blkif->xenblkd = NULL;
+}
+
+static void start_shutdown(struct xenbus_watch *watch,
+ const char **vec, unsigned int length)
+{
+ int err;
+ char *type;
+ unsigned int len;
+ struct backend_info *be
+ = container_of(watch, struct backend_info, shutdown_watch);
+ struct xenbus_device *dev = be->dev;
+
+ if (be->shutdown_signalled)
+ return;
+
+ type = xenbus_read(XBT_NIL, dev->nodename, "shutdown-request", &len);
+ err = (IS_ERR(type) ? PTR_ERR(type) : 0);
+
+ if (XENBUS_EXIST_ERR(err))
+ return;
+
+ if (err) {
+ xenbus_dev_fatal(dev, err, "reading shutdown-request");
+ return;
+ }
+
+ xenbus_switch_state(dev, XenbusStateClosing);
+
+ if (len == sizeof("force") - 1 && !memcmp(type, "force", len))
+ if (!kthread_remove(be))
+ signal_shutdown(be); /* shutdown immediately */
+
+ kfree(type);
+}
+
+int signal_tapdisk(struct backend_info *be)
+{
+ int err;
+
+ err = xenbus_write(XBT_NIL, be->nodename, "shutdown-tapdisk", "");
+ if (err)
+ WPRINTK("ERROR writing shutdown-tapdisk\n");
+
+ return err;
+}
+
+static void blktap_reconnect(struct backend_info *be)
+{
+ int err;
+ struct xenbus_device *dev = be->dev;
+
+ err = xenbus_rm(XBT_NIL, dev->nodename, "shutdown-done");
+ if (err) {
+ xenbus_dev_fatal(dev, err, "removing shutdown-done");
+ return;
+ }
+
+ err = xenbus_rm(XBT_NIL, dev->nodename, "shutdown-tapdisk");
+ if (err) {
+ xenbus_dev_fatal(dev, err, "removing shutdown-tapdisk");
+ return;
+ }
+
+ be->blkif->sectors = 0;
+ err = xenbus_rm(XBT_NIL, be->nodename, "info");
+ if (err) {
+ xenbus_dev_fatal(be->dev, err, "refreshing info");
+ return;
+ }
+
+ be->shutdown_signalled = 0;
+
+ xenbus_switch_state(dev, XenbusStateInitWait);
+}
+
static void tap_update_blkif_status(blkif_t *blkif)
{
int err;
int tap_blkif_connected(blkif_t *blkif)
{
- return (blkif->be && blkif->be->dev->state == XenbusStateConnected);
+ return (blkif->irq && blkif->blk_rings.common.sring);
}
/**
be->dev = dev;
dev->dev.driver_data = be;
+ atomic_set(&be->refcnt, 1);
+
+ be->dom_id = get_dom_id(dev->nodename);
be->xenbus_id = get_id(dev->nodename);
+ if (be->xenbus_id == -1 || be->dom_id == -1) {
+ xenbus_dev_fatal(dev, -EINVAL,
+ "getting dom/bus id");
+ kfree(be);
+ return -EINVAL;
+ }
+
+ be->nodename = kasprintf(GFP_KERNEL, "%s", dev->nodename);
+ if (!be->nodename) {
+ xenbus_dev_fatal(dev, -ENOMEM,
+ "allocating backend structure");
+ kfree(be);
+ return -ENOMEM;
+ }
+
+ link_backend_device(be);
be->blkif = tap_alloc_blkif(dev->otherend_id);
if (IS_ERR(be->blkif)) {
&be->backend_watch, tap_backend_changed);
if (err)
goto fail;
-
+
+ err = xenbus_watch_path2(dev, dev->nodename, "shutdown-request",
+ &be->shutdown_watch, start_shutdown);
+ if (err)
+ goto fail;
+
err = xenbus_switch_state(dev, XenbusStateInitWait);
if (err)
goto fail;
/**
* Check to see whether userspace code has opened the image
- * and written sector
- * and disk info to xenstore
+ * and written sector and disk info to xenstore
*/
err = xenbus_gather(XBT_NIL, dev->nodename, "info", "%lu", &info,
NULL);
err = xenbus_gather(XBT_NIL, dev->nodename, "sectors", "%llu",
&be->blkif->sectors, NULL);
+ if (err) {
+ xenbus_dev_error(dev, err, "getting sectors");
+ return;
+ }
if (be->blkif->xenblkd == NULL) {
char name[TASK_COMM_LEN];
return;
}
+ atomic_inc(&be->refcnt);
+ be->kthread_pid = be->blkif->xenblkd->pid;
+
err = xenbus_printf(XBT_NIL, dev->nodename, "kthread-pid",
"%d", be->blkif->xenblkd->pid);
if (err) {
struct backend_info *be = dev->dev.driver_data;
int err;
- DPRINTK("\n");
+ DPRINTK("%s: front end: %s\n",
+ dev->nodename, xenbus_strstate(frontend_state));
switch (frontend_state) {
case XenbusStateInitialising:
if (dev->state == XenbusStateClosed) {
printk(KERN_INFO "%s: %s: prepare for reconnect\n",
__FUNCTION__, dev->nodename);
- xenbus_switch_state(dev, XenbusStateInitWait);
+
+ blktap_reconnect(be);
}
break;
break;
case XenbusStateClosing:
- tap_blkif_unmap(be->blkif);
xenbus_switch_state(dev, XenbusStateClosing);
break;
case XenbusStateClosed:
- xenbus_switch_state(dev, XenbusStateClosed);
- if (xenbus_dev_is_online(dev))
- break;
- /* fall through if not online */
+ if (!kthread_remove(be))
+ signal_shutdown(be);
+ break;
+
case XenbusStateUnknown:
device_unregister(&dev->dev);
break;
frontend_state);
break;
}
+
+ DPRINTK("%s: back end: %s\n",
+ dev->nodename, xenbus_strstate(dev->state));
}
projects / people / ssmith / nc2-2.6.27.bak / .git / commitdiff