drbd: make drbd known to lsblk: use bd_link_disk_holder

lsblk should be able to pick up stacking device driver relations
involving DRBD conveniently.

Even though upstream kernel since 2011 says
	"DON'T USE THIS UNLESS YOU'RE ALREADY USING IT."
a new user has been added since (bcache),
which sets the precedences for us to use it as well.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

diff --git a/drivers/block/drbd/drbd_int.h b/drivers/block/drbd/drbd_int.h
index 08f266e..a262653 100644 (file)
--- a/drivers/block/drbd/drbd_int.h
+++ b/drivers/block/drbd/drbd_int.h
@@ -1126,7 +1126,7 @@ extern int drbd_send_ov_request(struct drbd_peer_device *, sector_t sector, int
 extern int drbd_send_bitmap(struct drbd_device *device);
 extern void drbd_send_sr_reply(struct drbd_peer_device *, enum drbd_state_rv retcode);
 extern void conn_send_sr_reply(struct drbd_connection *connection, enum drbd_state_rv retcode);
-extern void drbd_free_ldev(struct drbd_backing_dev *ldev);
+extern void drbd_backing_dev_free(struct drbd_device *device, struct drbd_backing_dev *ldev);
 extern void drbd_device_cleanup(struct drbd_device *device);
 void drbd_print_uuids(struct drbd_device *device, const char *text);
 

diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c
index a4aa7eb..136fa73 100644 (file)
--- a/drivers/block/drbd/drbd_main.c
+++ b/drivers/block/drbd/drbd_main.c
@@ -1992,7 +1992,7 @@ void drbd_device_cleanup(struct drbd_device *device)
                drbd_bm_cleanup(device);
        }
 
-       drbd_free_ldev(device->ldev);
+       drbd_backing_dev_free(device, device->ldev);
        device->ldev = NULL;
 
        clear_bit(AL_SUSPENDED, &device->flags);
@@ -2171,7 +2171,7 @@ void drbd_destroy_device(struct kref *kref)
        if (device->this_bdev)
                bdput(device->this_bdev);
 
-       drbd_free_ldev(device->ldev);
+       drbd_backing_dev_free(device, device->ldev);
        device->ldev = NULL;
 
        drbd_release_all_peer_reqs(device);
@@ -2964,18 +2964,6 @@ fail:
        return err;
 }
 
-void drbd_free_ldev(struct drbd_backing_dev *ldev)
-{
-       if (ldev == NULL)
-               return;
-
-       blkdev_put(ldev->backing_bdev, FMODE_READ | FMODE_WRITE | FMODE_EXCL);
-       blkdev_put(ldev->md_bdev, FMODE_READ | FMODE_WRITE | FMODE_EXCL);
-
-       kfree(ldev->disk_conf);
-       kfree(ldev);
-}
-
 static void drbd_free_one_sock(struct drbd_socket *ds)
 {
        struct socket *s;

diff --git a/drivers/block/drbd/drbd_nl.c b/drivers/block/drbd/drbd_nl.c
index 4703f1a..ee34739 100644 (file)
--- a/drivers/block/drbd/drbd_nl.c
+++ b/drivers/block/drbd/drbd_nl.c
@@ -1471,6 +1471,88 @@ success:
        return 0;
 }
 
+static struct block_device *open_backing_dev(struct drbd_device *device,
+               const char *bdev_path, void *claim_ptr, bool do_bd_link)
+{
+       struct block_device *bdev;
+       int err = 0;
+
+       bdev = blkdev_get_by_path(bdev_path,
+                                 FMODE_READ | FMODE_WRITE | FMODE_EXCL, claim_ptr);
+       if (IS_ERR(bdev)) {
+               drbd_err(device, "open(\"%s\") failed with %ld\n",
+                               bdev_path, PTR_ERR(bdev));
+               return bdev;
+       }
+
+       if (!do_bd_link)
+               return bdev;
+
+       err = bd_link_disk_holder(bdev, device->vdisk);
+       if (err) {
+               blkdev_put(bdev, FMODE_READ | FMODE_WRITE | FMODE_EXCL);
+               drbd_err(device, "bd_link_disk_holder(\"%s\", ...) failed with %d\n",
+                               bdev_path, err);
+               bdev = ERR_PTR(err);
+       }
+       return bdev;
+}
+
+static int open_backing_devices(struct drbd_device *device,
+               struct disk_conf *new_disk_conf,
+               struct drbd_backing_dev *nbc)
+{
+       struct block_device *bdev;
+
+       bdev = open_backing_dev(device, new_disk_conf->backing_dev, device, true);
+       if (IS_ERR(bdev))
+               return ERR_OPEN_DISK;
+       nbc->backing_bdev = bdev;
+
+       /*
+        * meta_dev_idx >= 0: external fixed size, possibly multiple
+        * drbd sharing one meta device.  TODO in that case, paranoia
+        * check that [md_bdev, meta_dev_idx] is not yet used by some
+        * other drbd minor!  (if you use drbd.conf + drbdadm, that
+        * should check it for you already; but if you don't, or
+        * someone fooled it, we need to double check here)
+        */
+       bdev = open_backing_dev(device, new_disk_conf->meta_dev,
+               /* claim ptr: device, if claimed exclusively; shared drbd_m_holder,
+                * if potentially shared with other drbd minors */
+                       (new_disk_conf->meta_dev_idx < 0) ? (void*)device : (void*)drbd_m_holder,
+               /* avoid double bd_claim_by_disk() for the same (source,target) tuple,
+                * as would happen with internal metadata. */
+                       (new_disk_conf->meta_dev_idx != DRBD_MD_INDEX_FLEX_INT &&
+                        new_disk_conf->meta_dev_idx != DRBD_MD_INDEX_INTERNAL));
+       if (IS_ERR(bdev))
+               return ERR_OPEN_MD_DISK;
+       nbc->md_bdev = bdev;
+       return NO_ERROR;
+}
+
+static void close_backing_dev(struct drbd_device *device, struct block_device *bdev,
+       bool do_bd_unlink)
+{
+       if (!bdev)
+               return;
+       if (do_bd_unlink)
+               bd_unlink_disk_holder(bdev, device->vdisk);
+       blkdev_put(bdev, FMODE_READ | FMODE_WRITE | FMODE_EXCL);
+}
+
+void drbd_backing_dev_free(struct drbd_device *device, struct drbd_backing_dev *ldev)
+{
+       if (ldev == NULL)
+               return;
+
+       close_backing_dev(device, ldev->md_bdev, ldev->md_bdev != ldev->backing_bdev);
+       close_backing_dev(device, ldev->backing_bdev, true);
+
+       kfree(ldev->disk_conf);
+       kfree(ldev);
+}
+
 int drbd_adm_attach(struct sk_buff *skb, struct genl_info *info)
 {
        struct drbd_config_context adm_ctx;
@@ -1484,7 +1566,6 @@ int drbd_adm_attach(struct sk_buff *skb, struct genl_info *info)
        sector_t min_md_device_sectors;
        struct drbd_backing_dev *nbc = NULL; /* new_backing_conf */
        struct disk_conf *new_disk_conf = NULL;
-       struct block_device *bdev;
        struct lru_cache *resync_lru = NULL;
        struct fifo_buffer *new_plan = NULL;
        union drbd_state ns, os;
@@ -1572,35 +1653,9 @@ int drbd_adm_attach(struct sk_buff *skb, struct genl_info *info)
        }
        rcu_read_unlock();
 
-       bdev = blkdev_get_by_path(new_disk_conf->backing_dev,
-                                 FMODE_READ | FMODE_WRITE | FMODE_EXCL, device);
-       if (IS_ERR(bdev)) {
-               drbd_err(device, "open(\"%s\") failed with %ld\n", new_disk_conf->backing_dev,
-                       PTR_ERR(bdev));
-               retcode = ERR_OPEN_DISK;
-               goto fail;
-       }
-       nbc->backing_bdev = bdev;
-
-       /*
-        * meta_dev_idx >= 0: external fixed size, possibly multiple
-        * drbd sharing one meta device.  TODO in that case, paranoia
-        * check that [md_bdev, meta_dev_idx] is not yet used by some
-        * other drbd minor!  (if you use drbd.conf + drbdadm, that
-        * should check it for you already; but if you don't, or
-        * someone fooled it, we need to double check here)
-        */
-       bdev = blkdev_get_by_path(new_disk_conf->meta_dev,
-                                 FMODE_READ | FMODE_WRITE | FMODE_EXCL,
-                                 (new_disk_conf->meta_dev_idx < 0) ?
-                                 (void *)device : (void *)drbd_m_holder);
-       if (IS_ERR(bdev)) {
-               drbd_err(device, "open(\"%s\") failed with %ld\n", new_disk_conf->meta_dev,
-                       PTR_ERR(bdev));
-               retcode = ERR_OPEN_MD_DISK;
+       retcode = open_backing_devices(device, new_disk_conf, nbc);
+       if (retcode != NO_ERROR)
                goto fail;
-       }
-       nbc->md_bdev = bdev;
 
        if ((nbc->backing_bdev == nbc->md_bdev) !=
            (new_disk_conf->meta_dev_idx == DRBD_MD_INDEX_INTERNAL ||
@@ -1900,12 +1955,8 @@ int drbd_adm_attach(struct sk_buff *skb, struct genl_info *info)
  fail:
        conn_reconfig_done(connection);
        if (nbc) {
-               if (nbc->backing_bdev)
-                       blkdev_put(nbc->backing_bdev,
-                                  FMODE_READ | FMODE_WRITE | FMODE_EXCL);
-               if (nbc->md_bdev)
-                       blkdev_put(nbc->md_bdev,
-                                  FMODE_READ | FMODE_WRITE | FMODE_EXCL);
+               close_backing_dev(device, nbc->md_bdev, nbc->md_bdev != nbc->backing_bdev);
+               close_backing_dev(device, nbc->backing_bdev, true);
                kfree(nbc);
        }
        kfree(new_disk_conf);

diff --git a/drivers/block/drbd/drbd_worker.c b/drivers/block/drbd/drbd_worker.c
index 2f29bf3..eff716c 100644 (file)
--- a/drivers/block/drbd/drbd_worker.c
+++ b/drivers/block/drbd/drbd_worker.c
@@ -1841,7 +1841,7 @@ static void drbd_ldev_destroy(struct drbd_device *device)
        device->act_log = NULL;
 
        __acquire(local);
-       drbd_free_ldev(device->ldev);
+       drbd_backing_dev_free(device, device->ldev);
        device->ldev = NULL;
        __release(local);
 

diff --git a/include/linux/drbd.h b/include/linux/drbd.h
index 392fc0e..d6b3c99 100644 (file)
--- a/include/linux/drbd.h
+++ b/include/linux/drbd.h
@@ -51,7 +51,7 @@
 #endif
 
 extern const char *drbd_buildtag(void);
-#define REL_VERSION "8.4.5"
+#define REL_VERSION "8.4.6"
 #define API_VERSION 1
 #define PRO_VERSION_MIN 86
 #define PRO_VERSION_MAX 101