On Sat, Jan 29, 2022 at 2:32 AM Jeff Layton <jlayton@xxxxxxxxxx> wrote: > > I've noticed an intermittent hang waiting for caps in some testing. What > I see is that the client will try to get caps for an operation (e.g. a > read), and ends up waiting on the waitqueue forever. The caps debugfs > file however shows that the caps it's waiting on have already been > granted. > > The current grant handling code will wake the waitqueue when it sees > that there are newly-granted caps in the issued set. On an import > however, we'll end up adding a new cap first, which fools the logic into > thinking that nothing has changed. A later hack in the code works around > this, but only for auth caps. not right. handle_cap_import() saves old issued to extra_info->issued. > > Ensure we wake the waiters whenever we get an IMPORT that grants new > caps for the inode. > > URL: https://tracker.ceph.com/issues/54044 > Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx> > --- > fs/ceph/caps.c | 23 ++++++++++++----------- > 1 file changed, 12 insertions(+), 11 deletions(-) > > I'm still testing this patch, but I think this may be the cause of some > mysterious hangs I've hit in testing. > > diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c > index e668cdb9c99e..06b65a68e920 100644 > --- a/fs/ceph/caps.c > +++ b/fs/ceph/caps.c > @@ -3541,21 +3541,22 @@ static void handle_cap_grant(struct inode *inode, > fill_inline = true; > } > > - if (ci->i_auth_cap == cap && > - le32_to_cpu(grant->op) == CEPH_CAP_OP_IMPORT) { > + if (le32_to_cpu(grant->op) == CEPH_CAP_OP_IMPORT) { > if (newcaps & ~extra_info->issued) > wake = true; > > - if (ci->i_requested_max_size > max_size || > - !(le32_to_cpu(grant->wanted) & CEPH_CAP_ANY_FILE_WR)) { > - /* re-request max_size if necessary */ > - ci->i_requested_max_size = 0; > - wake = true; > - } > + if (ci->i_auth_cap == cap) { > + if (ci->i_requested_max_size > max_size || > + !(le32_to_cpu(grant->wanted) & CEPH_CAP_ANY_FILE_WR)) { > + /* re-request max_size if necessary */ > + ci->i_requested_max_size = 0; > + wake = true; > + } > > - ceph_kick_flushing_inode_caps(session, ci); > - spin_unlock(&ci->i_ceph_lock); > - up_read(&session->s_mdsc->snap_rwsem); > + ceph_kick_flushing_inode_caps(session, ci); > + spin_unlock(&ci->i_ceph_lock); > + up_read(&session->s_mdsc->snap_rwsem); > + } > } else { > spin_unlock(&ci->i_ceph_lock); > } > -- > 2.34.1 >
