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Commit 8fe39aac authored by Philipp Reisner's avatar Philipp Reisner
Browse files

drbd: device->ldev is not guaranteed on an D_ATTACHING disk 



Some parts of the code assumed that get_ldev_if_state(device, D_ATTACHING)
is sufficient to access the ldev member of the device object. That was
wrong. ldev may not be there or might be freed at any time if the device
has a disk state of D_ATTACHING.

bm_rw()
  Documented that drbd_bm_read() is only called from drbd_adm_attach.
  drbd_bm_write() is only called when a reference is held, and it is
  documented that a caller has to hold a reference before calling
  drbd_bm_write()

drbd_bm_write_page()
  Use get_ldev() instead of get_ldev_if_state(device, D_ATTACHING)

drbd_bmio_set_n_write()
  No longer use get_ldev_if_state(device, D_ATTACHING). All callers
  hold a reference to ldev now.

drbd_bmio_clear_n_write()
  All callers where holding a reference of ldev anyways. Remove the
  misleading get_ldev_if_state(device, D_ATTACHING)

drbd_reconsider_max_bio_size()
  Removed the get_ldev_if_state(device, D_ATTACHING). All callers
  now pass a struct drbd_backing_dev* when they have a proper
  reference, or a NULL pointer.
  Before this fix, the receiver could trigger a NULL pointer
  deref when in drbd_reconsider_max_bio_size()

drbd_bump_write_ordering()
  Used get_ldev_if_state(device, D_ATTACHING) with the wrong assumption.
  Remove it, and allow the caller to pass in a struct drbd_backing_dev*
  when the caller knows that accessing this bdev is safe.

Signed-off-by: default avatarPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: default avatarLars Ellenberg <lars.ellenberg@linbit.com>
parent e9526580

drivers/block/drbd/drbd_bitmap.c

+3 −1
Original line number Diff line number Diff line
@@ -1085,6 +1085,8 @@ static int bm_rw(struct drbd_device *device, int rw, unsigned flags, unsigned la 
		kfree(ctx);

		return -ENODEV;

	}

	/* Here D_ATTACHING is sufficient since drbd_bm_read() is called only from

	   drbd_adm_attach(), after device->ldev was assigned. */



	if (!ctx->flags)

		WARN_ON(!(BM_LOCKED_MASK & b->bm_flags));
@@ -1260,7 +1262,7 @@ int drbd_bm_write_page(struct drbd_device *device, unsigned int idx) __must_hold 
		.kref = { ATOMIC_INIT(2) },

	};



	if (!get_ldev_if_state(device, D_ATTACHING)) {  /* put is in bm_aio_ctx_destroy() */

	if (!get_ldev(device)) {  /* put is in bm_aio_ctx_destroy() */

		drbd_err(device, "ASSERT FAILED: get_ldev_if_state() == 1 in drbd_bm_write_page()\n");

		kfree(ctx);

		return -ENODEV;

drivers/block/drbd/drbd_int.h

+5 −4
Original line number Diff line number Diff line
@@ -984,8 +984,8 @@ extern int drbd_bitmap_io(struct drbd_device *device, 
extern int drbd_bitmap_io_from_worker(struct drbd_device *device,

		int (*io_fn)(struct drbd_device *),

		char *why, enum bm_flag flags);

extern int drbd_bmio_set_n_write(struct drbd_device *device);

extern int drbd_bmio_clear_n_write(struct drbd_device *device);

extern int drbd_bmio_set_n_write(struct drbd_device *device) __must_hold(local);

extern int drbd_bmio_clear_n_write(struct drbd_device *device) __must_hold(local);

extern void drbd_ldev_destroy(struct drbd_device *device);



/* Meta data layout
@@ -1313,7 +1313,7 @@ enum determine_dev_size { 
extern enum determine_dev_size

drbd_determine_dev_size(struct drbd_device *, enum dds_flags, struct resize_parms *) __must_hold(local);

extern void resync_after_online_grow(struct drbd_device *);

extern void drbd_reconsider_max_bio_size(struct drbd_device *device);

extern void drbd_reconsider_max_bio_size(struct drbd_device *device, struct drbd_backing_dev *bdev);

extern enum drbd_state_rv drbd_set_role(struct drbd_device *device,

					enum drbd_role new_role,

					int force);
@@ -1479,7 +1479,8 @@ static inline void drbd_generic_make_request(struct drbd_device *device, 
		generic_make_request(bio);

}



void drbd_bump_write_ordering(struct drbd_resource *resource, enum write_ordering_e wo);

void drbd_bump_write_ordering(struct drbd_resource *resource, struct drbd_backing_dev *bdev,

			      enum write_ordering_e wo);



/* drbd_proc.c */

extern struct proc_dir_entry *drbd_proc;

drivers/block/drbd/drbd_main.c

+14 −22
Original line number Diff line number Diff line
@@ -3466,11 +3466,10 @@ void drbd_uuid_set_bm(struct drbd_device *device, u64 val) __must_hold(local) 
 *

 * Sets all bits in the bitmap and writes the whole bitmap to stable storage.

 */

int drbd_bmio_set_n_write(struct drbd_device *device)

int drbd_bmio_set_n_write(struct drbd_device *device) __must_hold(local)

{

	int rv = -EIO;



	if (get_ldev_if_state(device, D_ATTACHING)) {

	drbd_md_set_flag(device, MDF_FULL_SYNC);

	drbd_md_sync(device);

	drbd_bm_set_all(device);
@@ -3482,9 +3481,6 @@ int drbd_bmio_set_n_write(struct drbd_device *device) 
		drbd_md_sync(device);

	}



		put_ldev(device);

	}



	return rv;

}
@@ -3494,18 +3490,11 @@ int drbd_bmio_set_n_write(struct drbd_device *device) 
 *

 * Clears all bits in the bitmap and writes the whole bitmap to stable storage.

 */

int drbd_bmio_clear_n_write(struct drbd_device *device)

int drbd_bmio_clear_n_write(struct drbd_device *device) __must_hold(local)

{

	int rv = -EIO;



	drbd_resume_al(device);

	if (get_ldev_if_state(device, D_ATTACHING)) {

	drbd_bm_clear_all(device);

		rv = drbd_bm_write(device);

		put_ldev(device);

	}



	return rv;

	return drbd_bm_write(device);

}



static int w_bitmap_io(struct drbd_work *w, int unused)
@@ -3603,6 +3592,9 @@ static int w_go_diskless(struct drbd_work *w, int unused) 
 * that drbd_set_out_of_sync() can not be called. This function MAY ONLY be

 * called from worker context. It MUST NOT be used while a previous such

 * work is still pending!

 *

 * Its worker function encloses the call of io_fn() by get_ldev() and

 * put_ldev().

 */

void drbd_queue_bitmap_io(struct drbd_device *device,

			  int (*io_fn)(struct drbd_device *),

drivers/block/drbd/drbd_nl.c

+26 −15
Original line number Diff line number Diff line
@@ -1110,15 +1110,16 @@ static int drbd_check_al_size(struct drbd_device *device, struct disk_conf *dc) 
	return 0;

}



static void drbd_setup_queue_param(struct drbd_device *device, unsigned int max_bio_size)

static void drbd_setup_queue_param(struct drbd_device *device, struct drbd_backing_dev *bdev,

				   unsigned int max_bio_size)

{

	struct request_queue * const q = device->rq_queue;

	unsigned int max_hw_sectors = max_bio_size >> 9;

	unsigned int max_segments = 0;

	struct request_queue *b = NULL;



	if (get_ldev_if_state(device, D_ATTACHING)) {

		b = device->ldev->backing_bdev->bd_disk->queue;

	if (bdev) {

		b = bdev->backing_bdev->bd_disk->queue;



		max_hw_sectors = min(queue_max_hw_sectors(b), max_bio_size >> 9);

		rcu_read_lock();
@@ -1163,11 +1164,10 @@ static void drbd_setup_queue_param(struct drbd_device *device, unsigned int max_ 
				 b->backing_dev_info.ra_pages);

			q->backing_dev_info.ra_pages = b->backing_dev_info.ra_pages;

		}

		put_ldev(device);

	}

}



void drbd_reconsider_max_bio_size(struct drbd_device *device)

void drbd_reconsider_max_bio_size(struct drbd_device *device, struct drbd_backing_dev *bdev)

{

	unsigned int now, new, local, peer;
@@ -1175,10 +1175,9 @@ void drbd_reconsider_max_bio_size(struct drbd_device *device) 
	local = device->local_max_bio_size; /* Eventually last known value, from volatile memory */

	peer = device->peer_max_bio_size; /* Eventually last known value, from meta data */



	if (get_ldev_if_state(device, D_ATTACHING)) {

		local = queue_max_hw_sectors(device->ldev->backing_bdev->bd_disk->queue) << 9;

	if (bdev) {

		local = queue_max_hw_sectors(bdev->backing_bdev->bd_disk->queue) << 9;

		device->local_max_bio_size = local;

		put_ldev(device);

	}

	local = min(local, DRBD_MAX_BIO_SIZE);
@@ -1211,7 +1210,7 @@ void drbd_reconsider_max_bio_size(struct drbd_device *device) 
	if (new != now)

		drbd_info(device, "max BIO size = %u\n", new);



	drbd_setup_queue_param(device, new);

	drbd_setup_queue_param(device, bdev, new);

}



/* Starts the worker thread */
@@ -1399,7 +1398,7 @@ int drbd_adm_disk_opts(struct sk_buff *skb, struct genl_info *info) 
	else

		set_bit(MD_NO_FUA, &device->flags);



	drbd_bump_write_ordering(device->resource, WO_bdev_flush);

	drbd_bump_write_ordering(device->resource, NULL, WO_bdev_flush);



	drbd_md_sync(device);
@@ -1704,7 +1703,7 @@ int drbd_adm_attach(struct sk_buff *skb, struct genl_info *info) 
	new_disk_conf = NULL;

	new_plan = NULL;



	drbd_bump_write_ordering(device->resource, WO_bdev_flush);

	drbd_bump_write_ordering(device->resource, device->ldev, WO_bdev_flush);



	if (drbd_md_test_flag(device->ldev, MDF_CRASHED_PRIMARY))

		set_bit(CRASHED_PRIMARY, &device->flags);
@@ -1720,7 +1719,7 @@ int drbd_adm_attach(struct sk_buff *skb, struct genl_info *info) 
	device->read_cnt = 0;

	device->writ_cnt = 0;



	drbd_reconsider_max_bio_size(device);

	drbd_reconsider_max_bio_size(device, device->ldev);



	/* If I am currently not R_PRIMARY,

	 * but meta data primary indicator is set,
@@ -2648,8 +2647,13 @@ int drbd_adm_invalidate(struct sk_buff *skb, struct genl_info *info) 
	if (retcode != NO_ERROR)

		goto out;



	mutex_lock(&adm_ctx.resource->adm_mutex);

	device = adm_ctx.device;

	if (!get_ldev(device)) {

		retcode = ERR_NO_DISK;

		goto out;

	}



	mutex_lock(&adm_ctx.resource->adm_mutex);



	/* If there is still bitmap IO pending, probably because of a previous

	 * resync just being finished, wait for it before requesting a new resync.
@@ -2673,6 +2677,7 @@ int drbd_adm_invalidate(struct sk_buff *skb, struct genl_info *info) 
		retcode = drbd_request_state(device, NS(conn, C_STARTING_SYNC_T));

	drbd_resume_io(device);

	mutex_unlock(&adm_ctx.resource->adm_mutex);

	put_ldev(device);

out:

	drbd_adm_finish(&adm_ctx, info, retcode);

	return 0;
@@ -2698,7 +2703,7 @@ static int drbd_adm_simple_request_state(struct sk_buff *skb, struct genl_info * 
	return 0;

}



static int drbd_bmio_set_susp_al(struct drbd_device *device)

static int drbd_bmio_set_susp_al(struct drbd_device *device) __must_hold(local)

{

	int rv;
@@ -2719,8 +2724,13 @@ int drbd_adm_invalidate_peer(struct sk_buff *skb, struct genl_info *info) 
	if (retcode != NO_ERROR)

		goto out;



	mutex_lock(&adm_ctx.resource->adm_mutex);

	device = adm_ctx.device;

	if (!get_ldev(device)) {

		retcode = ERR_NO_DISK;

		goto out;

	}



	mutex_lock(&adm_ctx.resource->adm_mutex);



	/* If there is still bitmap IO pending, probably because of a previous

	 * resync just being finished, wait for it before requesting a new resync.
@@ -2747,6 +2757,7 @@ int drbd_adm_invalidate_peer(struct sk_buff *skb, struct genl_info *info) 
		retcode = drbd_request_state(device, NS(conn, C_STARTING_SYNC_S));

	drbd_resume_io(device);

	mutex_unlock(&adm_ctx.resource->adm_mutex);

	put_ldev(device);

out:

	drbd_adm_finish(&adm_ctx, info, retcode);

	return 0;

drivers/block/drbd/drbd_receiver.c

+30 −13
Original line number Diff line number Diff line
@@ -1168,7 +1168,7 @@ static void drbd_flush(struct drbd_connection *connection) 
				/* would rather check on EOPNOTSUPP, but that is not reliable.

				 * don't try again for ANY return value != 0

				 * if (rv == -EOPNOTSUPP) */

				drbd_bump_write_ordering(connection->resource, WO_drain_io);

				drbd_bump_write_ordering(connection->resource, NULL, WO_drain_io);

			}

			put_ldev(device);

			kref_put(&device->kref, drbd_destroy_device);
@@ -1257,14 +1257,29 @@ static enum finish_epoch drbd_may_finish_epoch(struct drbd_connection *connectio 
	return rv;

}



static enum write_ordering_e

max_allowed_wo(struct drbd_backing_dev *bdev, enum write_ordering_e wo)

{

	struct disk_conf *dc;



	dc = rcu_dereference(bdev->disk_conf);



	if (wo == WO_bdev_flush && !dc->disk_flushes)

		wo = WO_drain_io;

	if (wo == WO_drain_io && !dc->disk_drain)

		wo = WO_none;



	return wo;

}



/**

 * drbd_bump_write_ordering() - Fall back to an other write ordering method

 * @connection:	DRBD connection.

 * @wo:		Write ordering method to try.

 */

void drbd_bump_write_ordering(struct drbd_resource *resource, enum write_ordering_e wo)

void drbd_bump_write_ordering(struct drbd_resource *resource, struct drbd_backing_dev *bdev,

			      enum write_ordering_e wo)

{

	struct disk_conf *dc;

	struct drbd_device *device;

	enum write_ordering_e pwo;

	int vnr;
@@ -1278,17 +1293,18 @@ void drbd_bump_write_ordering(struct drbd_resource *resource, enum write_orderin 
	wo = min(pwo, wo);

	rcu_read_lock();

	idr_for_each_entry(&resource->devices, device, vnr) {

		if (!get_ldev_if_state(device, D_ATTACHING))

			continue;

		dc = rcu_dereference(device->ldev->disk_conf);



		if (wo == WO_bdev_flush && !dc->disk_flushes)

			wo = WO_drain_io;

		if (wo == WO_drain_io && !dc->disk_drain)

			wo = WO_none;

		if (get_ldev(device)) {

			wo = max_allowed_wo(device->ldev, wo);

			if (device->ldev == bdev)

				bdev = NULL;

			put_ldev(device);

		}

	}

	rcu_read_unlock();



	if (bdev)

		wo = max_allowed_wo(bdev, wo);



	resource->write_ordering = wo;

	if (pwo != resource->write_ordering || wo == WO_bdev_flush)

		drbd_info(resource, "Method to ensure write ordering: %s\n", write_ordering_str[resource->write_ordering]);
@@ -3709,7 +3725,6 @@ static int receive_sizes(struct drbd_connection *connection, struct packet_info 
	}



	device->peer_max_bio_size = be32_to_cpu(p->max_bio_size);

	drbd_reconsider_max_bio_size(device);

	/* Leave drbd_reconsider_max_bio_size() before drbd_determine_dev_size().

	   In case we cleared the QUEUE_FLAG_DISCARD from our queue in

	   drbd_reconsider_max_bio_size(), we can be sure that after
@@ -3717,6 +3732,7 @@ static int receive_sizes(struct drbd_connection *connection, struct packet_info 


	ddsf = be16_to_cpu(p->dds_flags);

	if (get_ldev(device)) {

		drbd_reconsider_max_bio_size(device, device->ldev);

		dd = drbd_determine_dev_size(device, ddsf, NULL);

		put_ldev(device);

		if (dd == DS_ERROR)
@@ -3724,6 +3740,7 @@ static int receive_sizes(struct drbd_connection *connection, struct packet_info 
		drbd_md_sync(device);

	} else {

		/* I am diskless, need to accept the peer's size. */

		drbd_reconsider_max_bio_size(device, NULL);

		drbd_set_my_capacity(device, p_size);

	}