From 294e7e458763dc1d229cbbe7147a6034bfc6e39a Mon Sep 17 00:00:00 2001 From: tsutomu.owa@toshiba.co.jp Date: Fri, 15 Sep 2017 14:17:23 -0500 Subject: DLM: fix conversion deadlock when DLM_LKF_NODLCKWT flag is set When the DLM_LKF_NODLCKWT flag was set, even if conversion deadlock was detected, the caller of can_be_granted() was unknown. We change the behavior of can_be_granted() and change it to detect conversion deadlock regardless of whether the DLM_LKF_NODLCKWT flag is set or not. And depending on whether the DLM_LKF_NODLCKWT flag is set or not, we change the behavior at the caller of can_be_granted(). This fix has no effect except when using DLM_LKF_NODLCKWT flag. Currently, ocfs2 uses the DLM_LKF_NODLCKWT flag and does not expect a cancel operation from conversion deadlock when calling dlm_lock(). ocfs2 is implemented to perform a cancel operation by requesting BASTs (callback). Signed-off-by: Tadashi Miyauchi Signed-off-by: Tsutomu Owa Signed-off-by: David Teigland --- fs/dlm/lock.c | 42 +++++++++++++++++++++++------------------- 1 file changed, 23 insertions(+), 19 deletions(-) (limited to 'fs/dlm') diff --git a/fs/dlm/lock.c b/fs/dlm/lock.c index d4aaddec1b16..f145a2a9d6cb 100644 --- a/fs/dlm/lock.c +++ b/fs/dlm/lock.c @@ -2465,14 +2465,12 @@ static int can_be_granted(struct dlm_rsb *r, struct dlm_lkb *lkb, int now, if (lkb->lkb_exflags & DLM_LKF_CONVDEADLK) { lkb->lkb_grmode = DLM_LOCK_NL; lkb->lkb_sbflags |= DLM_SBF_DEMOTED; - } else if (!(lkb->lkb_exflags & DLM_LKF_NODLCKWT)) { - if (err) - *err = -EDEADLK; - else { - log_print("can_be_granted deadlock %x now %d", - lkb->lkb_id, now); - dlm_dump_rsb(r); - } + } else if (err) { + *err = -EDEADLK; + } else { + log_print("can_be_granted deadlock %x now %d", + lkb->lkb_id, now); + dlm_dump_rsb(r); } goto out; } @@ -2501,13 +2499,6 @@ static int can_be_granted(struct dlm_rsb *r, struct dlm_lkb *lkb, int now, return rv; } -/* FIXME: I don't think that can_be_granted() can/will demote or find deadlock - for locks pending on the convert list. Once verified (watch for these - log_prints), we should be able to just call _can_be_granted() and not - bother with the demote/deadlk cases here (and there's no easy way to deal - with a deadlk here, we'd have to generate something like grant_lock with - the deadlk error.) */ - /* Returns the highest requested mode of all blocked conversions; sets cw if there's a blocked conversion to DLM_LOCK_CW. */ @@ -2545,9 +2536,22 @@ static int grant_pending_convert(struct dlm_rsb *r, int high, int *cw, } if (deadlk) { - log_print("WARN: pending deadlock %x node %d %s", - lkb->lkb_id, lkb->lkb_nodeid, r->res_name); - dlm_dump_rsb(r); + /* + * If DLM_LKB_NODLKWT flag is set and conversion + * deadlock is detected, we request blocking AST and + * down (or cancel) conversion. + */ + if (lkb->lkb_exflags & DLM_LKF_NODLCKWT) { + if (lkb->lkb_highbast < lkb->lkb_rqmode) { + queue_bast(r, lkb, lkb->lkb_rqmode); + lkb->lkb_highbast = lkb->lkb_rqmode; + } + } else { + log_print("WARN: pending deadlock %x node %d %s", + lkb->lkb_id, lkb->lkb_nodeid, + r->res_name); + dlm_dump_rsb(r); + } continue; } @@ -3123,7 +3127,7 @@ static int do_convert(struct dlm_rsb *r, struct dlm_lkb *lkb) deadlock, so we leave it on the granted queue and return EDEADLK in the ast for the convert. */ - if (deadlk) { + if (deadlk && !(lkb->lkb_exflags & DLM_LKF_NODLCKWT)) { /* it's left on the granted queue */ revert_lock(r, lkb); queue_cast(r, lkb, -EDEADLK); -- cgit v1.2.3