On Mon, Mar 16, 2020 at 8:50 PM Jeff Layton <jlayton@xxxxxxxxxx> wrote:
>
> On Tue, 2020-03-10 at 19:34 +0800, Yan, Zheng wrote:
> > Returns 0 if caps were not able to be acquired (yet), 1 if succeed,
> > or a negative error code. There are 3 speical error codes:
> >
> > -EAGAIN: need to sleep but non-blocking is specified
> > -EFBIG: ask caller to call check_max_size() and try again.
> > -ESTALE: ask caller to call ceph_renew_caps() and try again.
> >
> > Signed-off-by: "Yan, Zheng" <zyan@xxxxxxxxxx>
> > ---
> > fs/ceph/caps.c | 25 ++++++++++++++-----------
> > 1 file changed, 14 insertions(+), 11 deletions(-)
> >
> > diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c
> > index 342a32c74c64..804f4c65251a 100644
> > --- a/fs/ceph/caps.c
> > +++ b/fs/ceph/caps.c
> > @@ -2530,10 +2530,11 @@ void ceph_take_cap_refs(struct ceph_inode_info *ci, int got,
> > * Note that caller is responsible for ensuring max_size increases are
> > * requested from the MDS.
> > *
> > - * Returns 0 if caps were not able to be acquired (yet), a 1 if they were,
> > - * or a negative error code.
> > - *
> > - * FIXME: how does a 0 return differ from -EAGAIN?
> > + * Returns 0 if caps were not able to be acquired (yet), 1 if succeed,
> > + * or a negative error code. There are 3 speical error codes:
> > + * -EAGAIN: need to sleep but non-blocking is specified
> > + * -EFBIG: ask caller to call check_max_size() and try again.
> > + * -ESTALE: ask caller to call ceph_renew_caps() and try again.
> > */
> > enum {
> > /* first 8 bits are reserved for CEPH_FILE_MODE_FOO */
> > @@ -2581,7 +2582,7 @@ static int try_get_cap_refs(struct inode *inode, int need, int want,
> > dout("get_cap_refs %p endoff %llu > maxsize %llu\n",
> > inode, endoff, ci->i_max_size);
> > if (endoff > ci->i_requested_max_size)
> > - ret = -EAGAIN;
> > + ret = -EFBIG;
> > goto out_unlock;
> > }
> > /*
> > @@ -2743,7 +2744,10 @@ int ceph_try_get_caps(struct inode *inode, int need, int want,
> > flags |= NON_BLOCKING;
> >
> > ret = try_get_cap_refs(inode, need, want, 0, flags, got);
> > - return ret == -EAGAIN ? 0 : ret;
> > + /* three special error codes */
> > + if (ret == -EAGAIN || ret == -EFBIG || ret == -EAGAIN)
> > + ret = 0;
> > + return ret;
> > }
> >
> > /*
> > @@ -2771,17 +2775,12 @@ int ceph_get_caps(struct file *filp, int need, int want,
> > flags = get_used_fmode(need | want);
> >
> > while (true) {
> > - if (endoff > 0)
> > - check_max_size(inode, endoff);
> > -
> > flags &= CEPH_FILE_MODE_MASK;
> > if (atomic_read(&fi->num_locks))
> > flags |= CHECK_FILELOCK;
> > _got = 0;
> > ret = try_get_cap_refs(inode, need, want, endoff,
> > flags, &_got);
> > - if (ret == -EAGAIN)
> > - continue;
>
> Ok, so I guess we don't expect to see this error here since we didn't
> set NON_BLOCKING. The error returns from try_get_cap_refs are pretty
> complex, and I worry a little about future changes subtly breaking some
> of these assumptions.
>
> Maybe a WARN_ON_ONCE(ret == -EAGAIN) here would be good?
>
make sense. Please edit the patch if you don't have other comments.
Regards
Yan, Zheng
> > if (!ret) {
> > struct ceph_mds_client *mdsc = fsc->mdsc;
> > struct cap_wait cw;
> > @@ -2829,6 +2828,10 @@ int ceph_get_caps(struct file *filp, int need, int want,
> > }
> >
> > if (ret < 0) {
> > + if (ret == -EFBIG) {
> > + check_max_size(inode, endoff);
> > + continue;
> > + }
> > if (ret == -ESTALE) {
> > /* session was killed, try renew caps */
> > ret = ceph_renew_caps(inode, flags);
>
> --
> Jeff Layton <jlayton@xxxxxxxxxx>
>
