The recent fix to put_ldev() (correct ordering of access to local_cnt
and state.disk; memory barrier in __drbd_set_state) guarantees
that the cleanup happens exactly once.
However it does not yet guarantee that the cleanup happens from worker
context, the last put_ldev() may still happen from atomic context,
which must not happen: blkdev_put() may sleep.
Fix this by scheduling the cleanup to the worker instead,
using a couple more bits in device->flags and a new helper,
drbd_device_post_work().
Generalized the "resync progress" work to cover these new work bits.
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
BUG: unable to handle kernel NULL pointer dereference at 0000000000000058
IP: bd_release+0x21/0x70
Process drbd_w_t7146
Call Trace:
close_bdev_exclusive
drbd_free_ldev [drbd]
drbd_ldev_destroy [drbd]
w_after_state_ch [drbd]
Race probably went like this:
state.disk = D_FAILED
... first one to hit zero during D_FAILED:
put_ldev() /* ----------------> 0 */
i = atomic_dec_return()
if (i == 0)
if (state.disk == D_FAILED)
schedule_work(go_diskless)
/* 1 <------ */ get_ldev_if_state()
go_diskless()
do_some_pre_cleanup() corresponding put_ldev():
force_state(D_DISKLESS) /* 0 <------ */ i = atomic_dec_return()
if (i == 0)
atomic_inc() /* ---------> 1 */
state.disk = D_DISKLESS
schedule_work(after_state_ch) /* execution pre-empted by IRQ ? */
after_state_ch()
put_ldev()
i = atomic_dec_return() /* 0 */
if (i == 0)
if (state.disk == D_DISKLESS) if (state.disk == D_DISKLESS)
drbd_ldev_destroy() drbd_ldev_destroy();
Trying to fix this by checking the disk state *before* the
atomic_dec_return(), which implies memory barriers, and by inserting
extra memory barriers around the state assignment in __drbd_set_state().
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
This fixes one recent regresion,
and one long existing bug.
The bug:
drbd_try_clear_on_disk_bm() assumed that all "count" bits have to be
accounted in the resync extent corresponding to the start sector.
Since we allow application requests to cross our "extent" boundaries,
this assumption is no longer true, resulting in possible misaccounting,
scary messages
("BAD! sector=12345s enr=6 rs_left=-7 rs_failed=0 count=58 cstate=..."),
and potentially, if the last bit to be cleared during resync would
reside in previously misaccounted resync extent, the resync would never
be recognized as finished, but would be "stalled" forever, even though
all blocks are in sync again and all bits have been cleared...
The regression was introduced by
drbd: get rid of atomic update on disk bitmap works
For an "empty" resync (rs_total == 0), we must not "finish" the
resync on the SyncSource before the SyncTarget knows all relevant
information (sync uuid). We need to wait for the full round-trip,
the SyncTarget will then explicitly notify us.
Also for normal, non-empty resyncs (rs_total > 0), the resync-finished
condition needs to be tested before the schedule() in wait_for_work, or
it is likely to be missed.
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
Just trigger the occasional lazy bitmap write-out during resync
from the central wait_for_work() helper.
Previously, during resync, bitmap pages would be written out separately,
synchronously, one at a time, at least 8 times each (every 512 bytes
worth of bitmap cleared).
Now we trigger "merge friendly" bulk write out of all cleared pages
every two seconds during resync, and once the resync is finished.
Most pages will be written out only once.
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
Since the member of drbd_device is called ldev
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
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: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
If there are no peer_devices or connections, I'd rather have NULL
than some "arbitrary" address pretending to point to a struct.
Helps to avoid hard to debug symptoms, in case we ever try to use
and dereference a drbd_connection or drbd_peer_device
where we in fact don't have any connection at all.
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>
When batching more updates to the activity log into single transactions,
we lost the ability for new requests to force themselves into the active
set: all preparation steps became non-blocking, and if all currently
hot extents keep busy, they could starve out new incoming requests
to cold extents for quite a while.
This can only happen if your IO backend accepts more IO operations per
average DRBD replication round trip time than you have al-extents
configured.
If we have incoming requests to cold extents,
at least do one blocking update per transaction.
In an artificial worst-case workload on SSD with an asynchronous 600 ms
replication link, with al-extents = 7 (the minimum we allow), and
concurrent full resynch, without this patch, some write requests have
been observed to be starved for 40 seconds.
With this patch, application observed a worst case latency of twice the
replication round trip time.
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>
Allow the user of REQ_DISCARD.
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>
If the receiver needs to serve a discard request on a queue that does
not announce to be discard cabable, it falls back to do synchronous
blkdev_issue_zeroout().
We expect only "reasonably" large (up to one activity log extent?)
discard requests.
We do this to not to not block the receiver for too long in this
fallback code path, and to not set/clear too many bits inside one
spinlock_irq_save() in drbd_set_in_sync/drbd_set_out_of_sync,
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>
We plan to use genl_family->parallel_ops = true in the future,
but need to review all possible interactions first.
For now, only selectively drop genl_lock() in drbd_set_role(),
instead serializing on our own internal resource->conf_update mutex.
We now can be promoted/demoted on many resources in parallel,
which may significantly improve cluster failover times
when fencing is required.
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>
Because all administrative requests via genetlink have been globally
serialized via genl_lock(), we used to have one static struct
drbd_config_context "admin context".
Move this on-stack to the respective callback functions.
This will allow us to selectively drop the genl_lock()
(or use genl_family->parallel_ops) in the future.
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>
Before, application IO could pre-empt resync activity
for up to hardcoded 20 seconds per resync request.
A very busy server could throttle the effective resync bandwidth
down to one request per 20 seconds.
Now, we only let application IO pre-empt resync traffic
while the current resync rate estimate is above c-min-rate.
If you disable the c-min-rate throttle feature (set c-min-rate = 0),
application IO will no longer pre-empt resync traffic at all.
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>
In the drbd_thread "infrastructure" functions, only use the resource instead of
the connection. Make the connection field of drbd_thread optional. This will
allow to introduce threads which are not associated with a connection.
Signed-off-by: Andreas Gruenbacher <agruen@linbit.com>
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
The new function can flush any work queue, not just the work queue of the data
socket of a connection.
Signed-off-by: Andreas Gruenbacher <agruen@linbit.com>
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
drbd_device_work is a work item that has a reference to a device,
while drbd_work is a more generic work item that does not carry
a reference to a device.
All callbacks get a pointer to a drbd_work instance, those callbacks
that expect a drbd_device_work use the container_of macro to get it.
Signed-off-by: Andreas Gruenbacher <agruen@linbit.com>
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Also move it to drbd_receiver.c and make it static.
Signed-off-by: Andreas Gruenbacher <agruen@linbit.com>
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
The new function returns a peer device, which allows us to eliminate a few
instances of first_peer_device().
Signed-off-by: Andreas Gruenbacher <agruen@linbit.com>
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Also fix drbd_calc_cpu_mask() to spread resources equally over all online cpus
independent of device minor numbers.
Signed-off-by: Andreas Gruenbacher <agruen@linbit.com>
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
The implicit dependency on a variable inside the macro is problematic.
Signed-off-by: Andreas Gruenbacher <agruen@linbit.com>
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
With the polymorphic drbd_() macros, we no longer need the connection
specific variants.
Signed-off-by: Andreas Gruenbacher <agruen@linbit.com>
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
This allows drbd_alert(), drbd_err(), drbd_warn(), and drbd_info() to work for
a resource, device, or connection so that we don't have to introduce three
separate sets of macros for that.
The drbd_printk() macro itself is pretty ugly, but that problem is limited to
one place in the code. Using drbd_printk() on an object type which it doesn't
understand results in an undefined drbd_printk_with_wrong_object_type symbol.
Signed-off-by: Andreas Gruenbacher <agruen@linbit.com>
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
DRBD was using dev_err() and similar all over the code; instead of having to
write dev_err(disk_to_dev(device->vdisk), ...) to convert a drbd_device into a
kernel device, a DEV macro was used which implicitly references the device
variable. This is terrible; introduce separate drbd_err() and similar macros
with an explicit device parameter instead.
Signed-off-by: Andreas Gruenbacher <agruen@linbit.com>
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Let connection->peer_devices point to peer devices; connection->volumes was
pointing to devices.
Signed-off-by: Andreas Gruenbacher <agruen@linbit.com>
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
So far, connections and resources always come in pairs, but in the future with
multiple connections per resource, the names will stick with the resources.
Signed-off-by: Andreas Gruenbacher <agruen@linbit.com>
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
This allows to access the volumes of a resource by number.
Signed-off-by: Andreas Gruenbacher <agruen@linbit.com>
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
In a first step, each resource has exactly one connection, and both objects are
allocated at the same time. The final result will be one resource and zero or
more connections.
Only allow to delete a resource if all its connections are C_STANDALONE.
Stop the worker threads of all connections early enough.
Signed-off-by: Andreas Gruenbacher <agruen@linbit.com>
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
In a setup where a device (aka volume) can replicate to multiple peers and one
connection can be shared between multiple devices, we need separate objects to
represent devices on peer nodes and network connections.
As a first step to introduce multiple connections per device, give each
drbd_device object a single drbd_peer_device object which connects it to a
drbd_connection object.
Signed-off-by: Andreas Gruenbacher <agruen@linbit.com>
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
sed -i -e 's:all_tconn:connections:g' -e 's:tconn:connection:g'
Signed-off-by: Andreas Gruenbacher <agruen@linbit.com>
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
sed -i -e 's:\<drbd_conf\>:drbd_device:g'
Signed-off-by: Andreas Gruenbacher <agruen@linbit.com>
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Keep the protocol definitions separate from the kernel code; they are useful in
their own right.
Signed-off-by: Andreas Gruenbacher <agruen@linbit.com>
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Move prototype declaration of functions drbdd_init() and drbd_asender()
from drbd/drbd_main.c to header file drbd/drbd_int.h because these
functions are used by more than one file.
This eliminates the following warning in drbd/drbd_receiver.c:
drivers/block/drbd/drbd_receiver.c:4836:5: warning: no previous prototype for ‘drbdd_init’ [-Wmissing-prototypes]
drivers/block/drbd/drbd_receiver.c:5245:5: warning: no previous prototype for ‘drbd_asender’ [-Wmissing-prototypes]
Signed-off-by: Rashika Kheria <rashika.kheria@gmail.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Move the prototype declaration of function tl_abort_disk_io() from
drbd/drbd_state.c to appropriate header file drbd/drbd_int.h because it
is used by more than 2 files.
This eliminates the following warnings in drbd/drbd_main.c:
drivers/block/drbd/drbd_main.c:310:6: warning: no previous prototype for ‘tl_abort_disk_io’ [-Wmissing-prototypes]
Signed-off-by: Rashika Kheria <rashika.kheria@gmail.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
