I don't think this fixes the issue. As in, the fix for reco+mig race is a lot more involved. Is someone hitting this freq? As in, this should be a hard race to reproduce.
On 08/31/2010 08:41 AM, Wengang Wang wrote: > This patch tries to fix two problems: > > problem 1): > It's a case of recovery + migration. That is a recovery is happening when > node I > is in progress of umount. Node I is the recovery master. > Say lockres A was mastered by the dead node and need to be recovered. Node > I(the > reco master) and node II both have reference on lockres A. > So lockres A is being recovered from node II to node I, with RECOVERING flag > set. > The umounting process is going on, it happened to be migrating lockres A to > node > II. Since recovery not finished yet(RECOVERING still set), node II reponds > with > -EFAULT to kill node I. Then node I killed its self(BUGON). > > There is a checking for recovery(on RECOVERING), but it droped res->spinlock > and > dlm->spinlock. So the checking does not help much enough. > > Since we have to drop any spinlock when we are sending migrate lockres( > DLM_MIG_LOCKRES_MSG) message, we have to deal with above case. > > problem 2): > In the same context of problem 1), -ENOMEM from target node can trigger an > incorrect BUG() on the requester of "migrate lockres". > > The fix is when target node returns -EFAULT or -ENOMEM, we retry the > migration( > for umount). > Though they are two separated problems, the fixes are in the same way. So I > combined them together. > > Signed-off-by: Wengang Wang<[email protected]> > --- > fs/ocfs2/dlm/dlmrecovery.c | 28 ++++++++++++++++++++++------ > 1 files changed, 22 insertions(+), 6 deletions(-) > > diff --git a/fs/ocfs2/dlm/dlmrecovery.c b/fs/ocfs2/dlm/dlmrecovery.c > index aaaffbc..b7dd03f 100644 > --- a/fs/ocfs2/dlm/dlmrecovery.c > +++ b/fs/ocfs2/dlm/dlmrecovery.c > @@ -1122,6 +1122,8 @@ static int dlm_send_mig_lockres_msg(struct dlm_ctxt > *dlm, > orig_flags& DLM_MRES_MIGRATION ? "migration" : "recovery", > send_to); > > +#define WAIT_FOR_NOMEM_MS 30 > +resend: > /* send it */ > ret = o2net_send_message(DLM_MIG_LOCKRES_MSG, dlm->key, mres, > sz, send_to,&status); > @@ -1132,16 +1134,30 @@ static int dlm_send_mig_lockres_msg(struct dlm_ctxt > *dlm, > "0x%x) to node %u\n", ret, DLM_MIG_LOCKRES_MSG, > dlm->key, send_to); > } else { > - /* might get an -ENOMEM back here */ > - ret = status; > if (ret< 0) { > mlog_errno(ret); > > - if (ret == -EFAULT) { > - mlog(ML_ERROR, "node %u told me to kill " > - "myself!\n", send_to); > - BUG(); > + /* > + * -ENOMEM or -EFAULT here. > + * -EFAULT means lockres is in recovery. > + * we should retry in both the two cases. > + */ > + ret = status; > + if (ret == -ENOMEM) { > + mlog(ML_NOTICE, "node %u no memory\n", > + send_to); > + if (dlm_in_recovery(dlm)) { > + dlm_wait_for_recovery(dlm); > + } else { > + msleep(WAIT_FOR_NOMEM_MS); > + } > + } else { > + BUG_ON(ret != -EFAULT); > + mlog(ML_NOTICE, "node %u in recovery\n", > + send_to); > + dlm_wait_for_recovery(dlm); > } > + goto resend; > } > } > > _______________________________________________ Ocfs2-devel mailing list [email protected] http://oss.oracle.com/mailman/listinfo/ocfs2-devel
