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| author | Lars Ellenberg <lars.ellenberg@linbit.com> | 2011-11-02 16:29:45 +0100 |
|---|---|---|
| committer | Philipp Reisner <philipp.reisner@linbit.com> | 2012-05-09 15:15:58 +0200 |
| commit | 763eb63625a625e4d160cbb4cce2bcdb40141b97 (patch) | |
| tree | 7399533f422da35884c7a67b9972b23757890256 /drivers/block/drbd | |
| parent | e89868a0927cfb8a3f535c938e5d6dd7edc6353c (diff) | |
| download | linux-763eb63625a625e4d160cbb4cce2bcdb40141b97.tar.gz linux-763eb63625a625e4d160cbb4cce2bcdb40141b97.tar.xz linux-763eb63625a625e4d160cbb4cce2bcdb40141b97.zip | |
drbd: fix potential spinlock deadlock
drbd_try_clear_on_disk_bm() has a sanity check for the number of blocks
left to be resynced (rs_left) in the current resync extent.
If it detects a mismatch, it complains, and forces a disconnect using
drbd_force_state(mdev, NS(conn, C_DISCONNECTING));
Unfortunately, this may be called while holding the req_lock,
and drbd_force_state() want's to aquire that lock itself. Deadlock.
Don't force a disconnect, but fix up rs_left by recounting and
reassigning the number of dirty blocks in that extent.
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
Diffstat (limited to 'drivers/block/drbd')
| -rw-r--r-- | drivers/block/drbd/drbd_actlog.c | 20 |
1 files changed, 12 insertions, 8 deletions
diff --git a/drivers/block/drbd/drbd_actlog.c b/drivers/block/drbd/drbd_actlog.c index 3d7c2153daca..601ad9ef0437 100644 --- a/drivers/block/drbd/drbd_actlog.c +++ b/drivers/block/drbd/drbd_actlog.c @@ -711,16 +711,20 @@ static void drbd_try_clear_on_disk_bm(struct drbd_conf *mdev, sector_t sector, else ext->rs_failed += count; if (ext->rs_left < ext->rs_failed) { - dev_err(DEV, "BAD! sector=%llus enr=%u rs_left=%d " - "rs_failed=%d count=%d\n", + dev_warn(DEV, "BAD! sector=%llus enr=%u rs_left=%d " + "rs_failed=%d count=%d cstate=%s\n", (unsigned long long)sector, ext->lce.lc_number, ext->rs_left, - ext->rs_failed, count); - dump_stack(); - - lc_put(mdev->resync, &ext->lce); - drbd_force_state(mdev, NS(conn, C_DISCONNECTING)); - return; + ext->rs_failed, count, + drbd_conn_str(mdev->state.conn)); + + /* We don't expect to be able to clear more bits + * than have been set when we originally counted + * the set bits to cache that value in ext->rs_left. + * Whatever the reason (disconnect during resync, + * delayed local completion of an application write), + * try to fix it up by recounting here. */ + ext->rs_left = drbd_bm_e_weight(mdev, enr); } } else { /* Normally this element should be in the cache, |