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| author | Philipp Reisner <philipp.reisner@linbit.com> | 2013-02-28 10:30:19 +0100 |
|---|---|---|
| committer | Jens Axboe <axboe@fb.com> | 2015-11-25 09:22:03 -0700 |
| commit | 7dbb4386b90a13a7b0cab12aae184e5e04c536c3 (patch) | |
| tree | 6a2d4915247505c314e8b3cceb2e1eeb45980cba | |
| parent | f85d9f2d02cdcd1b79e00fccd667b37b251ba3ac (diff) | |
| download | blackbird-op-linux-7dbb4386b90a13a7b0cab12aae184e5e04c536c3.tar.gz blackbird-op-linux-7dbb4386b90a13a7b0cab12aae184e5e04c536c3.zip | |
drbd: make suspend_io() / resume_io() must be thread and recursion safe
Avoid to prematurely resume application IO: don't set/clear a single
bit, but inc/dec an atomic counter.
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>
| -rw-r--r-- | drivers/block/drbd/drbd_int.h | 4 | ||||
| -rw-r--r-- | drivers/block/drbd/drbd_nl.c | 8 | ||||
| -rw-r--r-- | drivers/block/drbd/drbd_state.c | 2 |
3 files changed, 8 insertions, 6 deletions
diff --git a/drivers/block/drbd/drbd_int.h b/drivers/block/drbd/drbd_int.h index a26265375e1e..df3d89d5777a 100644 --- a/drivers/block/drbd/drbd_int.h +++ b/drivers/block/drbd/drbd_int.h @@ -500,7 +500,6 @@ enum { MD_NO_FUA, /* Users wants us to not use FUA/FLUSH on meta data dev */ - SUSPEND_IO, /* suspend application io */ BITMAP_IO, /* suspend application io; once no more io in flight, start bitmap io */ BITMAP_IO_QUEUED, /* Started bitmap IO */ @@ -880,6 +879,7 @@ struct drbd_device { atomic_t rs_pending_cnt; /* RS request/data packets on the wire */ atomic_t unacked_cnt; /* Need to send replies for */ atomic_t local_cnt; /* Waiting for local completion */ + atomic_t suspend_cnt; /* Interval tree of pending local requests */ struct rb_root read_requests; @@ -2263,7 +2263,7 @@ static inline bool may_inc_ap_bio(struct drbd_device *device) if (drbd_suspended(device)) return false; - if (test_bit(SUSPEND_IO, &device->flags)) + if (atomic_read(&device->suspend_cnt)) return false; /* to avoid potential deadlock or bitmap corruption, diff --git a/drivers/block/drbd/drbd_nl.c b/drivers/block/drbd/drbd_nl.c index 613778994b23..c7cd3df8107e 100644 --- a/drivers/block/drbd/drbd_nl.c +++ b/drivers/block/drbd/drbd_nl.c @@ -865,9 +865,11 @@ char *ppsize(char *buf, unsigned long long size) * and can be long lived. * This changes an device->flag, is triggered by drbd internals, * and should be short-lived. */ +/* It needs to be a counter, since multiple threads might + independently suspend and resume IO. */ void drbd_suspend_io(struct drbd_device *device) { - set_bit(SUSPEND_IO, &device->flags); + atomic_inc(&device->suspend_cnt); if (drbd_suspended(device)) return; wait_event(device->misc_wait, !atomic_read(&device->ap_bio_cnt)); @@ -875,8 +877,8 @@ void drbd_suspend_io(struct drbd_device *device) void drbd_resume_io(struct drbd_device *device) { - clear_bit(SUSPEND_IO, &device->flags); - wake_up(&device->misc_wait); + if (atomic_dec_and_test(&device->suspend_cnt)) + wake_up(&device->misc_wait); } /** diff --git a/drivers/block/drbd/drbd_state.c b/drivers/block/drbd/drbd_state.c index f022e99f9855..5a7ef7873b67 100644 --- a/drivers/block/drbd/drbd_state.c +++ b/drivers/block/drbd/drbd_state.c @@ -1484,7 +1484,7 @@ int drbd_bitmap_io_from_worker(struct drbd_device *device, D_ASSERT(device, current == first_peer_device(device)->connection->worker.task); /* open coded non-blocking drbd_suspend_io(device); */ - set_bit(SUSPEND_IO, &device->flags); + atomic_inc(&device->suspend_cnt); drbd_bm_lock(device, why, flags); rv = io_fn(device); |
