On Tue, Mar 29, 2022 at 09:06:23AM -0700, dai.ngo@xxxxxxxxxx wrote:
>
> On 3/29/22 8:24 AM, J. Bruce Fields wrote:
> >On Thu, Mar 24, 2022 at 09:34:45PM -0700, Dai Ngo wrote:
> >>Update nfs4_get_vfs_file and nfs4_upgrade_open to handle share
> >>reservation conflict with courtesy client.
> >>
> >>Update nfs4_get_vfs_file and nfs4_upgrade_open to handle share
> >>reservation conflict with courtesy client.
> >>
> >>When we have deny/access conflict we walk the fi_stateids of the
> >>file in question, looking for open stateid and check the deny/access
> >>of that stateid against the one from the open request. If there is
> >>a conflict then we check if the client that owns that stateid is
> >>a courtesy client. If it is then we set the client state to
> >>CLIENT_EXPIRED and allow the open request to continue. We have
> >>to scan all the stateid's of the file since the conflict can be
> >>caused by multiple open stateid's.
> >>
> >>Client with CLIENT_EXPIRED is expired by the laundromat.
> >>
> >>Signed-off-by: Dai Ngo <dai.ngo@xxxxxxxxxx>
> >>---
> >> fs/nfsd/nfs4state.c | 85 +++++++++++++++++++++++++++++++++++++++++++++--------
> >> 1 file changed, 72 insertions(+), 13 deletions(-)
> >>
> >>diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
> >>index f20c75890594..fe8969ba94b3 100644
> >>--- a/fs/nfsd/nfs4state.c
> >>+++ b/fs/nfsd/nfs4state.c
> >>@@ -701,9 +701,56 @@ __nfs4_file_get_access(struct nfs4_file *fp, u32 access)
> >> atomic_inc(&fp->fi_access[O_RDONLY]);
> >> }
> >>+/*
> >>+ * Check if courtesy clients have conflicting access and resolve it if possible
> >>+ *
> >>+ * access: is op_share_access if share_access is true.
> >>+ * Check if access mode, op_share_access, would conflict with
> >>+ * the current deny mode of the file 'fp'.
> >>+ * access: is op_share_deny if share_access is false.
> >>+ * Check if the deny mode, op_share_deny, would conflict with
> >>+ * current access of the file 'fp'.
> >>+ * stp: skip checking this entry.
> >>+ * new_stp: normal open, not open upgrade.
> >>+ *
> >>+ * Function returns:
> >>+ * false - access/deny mode conflict with normal client.
> >>+ * true - no conflict or conflict with courtesy client(s) is resolved.
> >>+ */
> >>+static bool
> >>+nfs4_resolve_deny_conflicts_locked(struct nfs4_file *fp, bool new_stp,
> >>+ struct nfs4_ol_stateid *stp, u32 access, bool share_access)
> >>+{
> >>+ struct nfs4_ol_stateid *st;
> >>+ struct nfs4_client *clp;
> >>+ bool conflict = true;
> >>+ unsigned char bmap;
> >>+
> >>+ lockdep_assert_held(&fp->fi_lock);
> >>+ list_for_each_entry(st, &fp->fi_stateids, st_perfile) {
> >>+ /* ignore lock stateid */
> >>+ if (st->st_openstp)
> >>+ continue;
> >>+ if (st == stp && new_stp)
> >>+ continue;
> >>+ /* check file access against deny mode or vice versa */
> >>+ bmap = share_access ? st->st_deny_bmap : st->st_access_bmap;
> >>+ if (!(access & bmap_to_share_mode(bmap)))
> >>+ continue;
> >As I said before, I recommend just doing *both* checks here. Then you
> >can remove the "bool share_access" argument. I think that'll make the
> >code easier to read.
>
> Bruce, I'm not clear how to check both here as I mentioned in my previous
> email.
>
> nfs4_resolve_deny_conflicts_locked is called from nfs4_file_get_access
> and nfs4_file_check_deny to check either access or deny mode separately
> so how do we check both access and deny in nfs4_resolve_deny_conflicts_locked?
Sorry, I forgot.
Uh, I guess on a quick skim I don't see a way to do that nicely, so,
fine, I'm OK with it as is.
--b.
