From: Lars Ellenberg Date: Mon, 2 May 2011 09:51:31 +0000 (+0200) Subject: drbd: fix schedule in atomic X-Git-Tag: firefly_0821_release~7613^2~1152^2~5 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=9a0d9d0389ef769e4b01abf50fcc11407706270b;p=firefly-linux-kernel-4.4.55.git drbd: fix schedule in atomic An administrative detach used to request a state change directly to D_DISKLESS, first suspending IO to avoid the last put_ldev() occuring from an endio handler, potentially in irq context. This is not enough on the receiving side (typically secondary), we may miss some peer_req on the way to local disk, which then may do the last put_ldev() from their drbd_peer_request_endio(). This patch makes the detach always go through the intermediate D_FAILED state. We may consider to rename it D_DETACHING. Alternative approach would be to create yet an other work item to be scheduled on the worker, do the destructor work from there, and get the timing right. manually picked commit 564040f from the drbd 8.4 branch. Signed-off-by: Philipp Reisner Signed-off-by: Lars Ellenberg --- diff --git a/drivers/block/drbd/drbd_int.h b/drivers/block/drbd/drbd_int.h index 8aa10391115b..a74d3ee04ba8 100644 --- a/drivers/block/drbd/drbd_int.h +++ b/drivers/block/drbd/drbd_int.h @@ -2157,6 +2157,10 @@ static inline int get_net_conf(struct drbd_conf *mdev) static inline void put_ldev(struct drbd_conf *mdev) { int i = atomic_dec_return(&mdev->local_cnt); + + /* This may be called from some endio handler, + * so we must not sleep here. */ + __release(local); D_ASSERT(i >= 0); if (i == 0) { diff --git a/drivers/block/drbd/drbd_nl.c b/drivers/block/drbd/drbd_nl.c index 7c64ec042124..13569635b922 100644 --- a/drivers/block/drbd/drbd_nl.c +++ b/drivers/block/drbd/drbd_nl.c @@ -1334,11 +1334,19 @@ static int drbd_nl_disk_conf(struct drbd_conf *mdev, struct drbd_nl_cfg_req *nlp static int drbd_nl_detach(struct drbd_conf *mdev, struct drbd_nl_cfg_req *nlp, struct drbd_nl_cfg_reply *reply) { + enum drbd_ret_code retcode; + int ret; drbd_suspend_io(mdev); /* so no-one is stuck in drbd_al_begin_io */ - reply->ret_code = drbd_request_state(mdev, NS(disk, D_DISKLESS)); - if (mdev->state.disk == D_DISKLESS) - wait_event(mdev->misc_wait, !atomic_read(&mdev->local_cnt)); + retcode = drbd_request_state(mdev, NS(disk, D_FAILED)); + /* D_FAILED will transition to DISKLESS. */ + ret = wait_event_interruptible(mdev->misc_wait, + mdev->state.disk != D_FAILED); drbd_resume_io(mdev); + if (retcode == SS_IS_DISKLESS) + retcode = SS_NOTHING_TO_DO; + if (ret) + retcode = ERR_INTR; + reply->ret_code = retcode; return 0; } diff --git a/include/linux/drbd.h b/include/linux/drbd.h index cec467f5d676..c86283b4fbab 100644 --- a/include/linux/drbd.h +++ b/include/linux/drbd.h @@ -53,7 +53,7 @@ extern const char *drbd_buildtag(void); -#define REL_VERSION "8.3.10" +#define REL_VERSION "8.3.11" #define API_VERSION 88 #define PRO_VERSION_MIN 86 #define PRO_VERSION_MAX 96