[PATCH RFC v15 0/11] NFSD: Initial implementation of NFSv4 Courteous Server

[PATCH RFC v15 0/11] NFSD: Initial implementation of NFSv4 Courteous Server

[Dai Ngo]

This series of patches implement the NFSv4 Courteous Server.

A server which does not immediately expunge the state on lease expiration
is known as a Courteous Server.  A Courteous Server continues to recognize
previously generated state tokens as valid until conflict arises between
the expired state and the requests from another client, or the server
reboots.

v2 patch includes:

. add new callback, lm_expire_lock, to lock_manager_operations to
  allow the lock manager to take appropriate action with conflict lock.

. handle conflicts of NFSv4 locks with NFSv3/NLM and local locks.

. expire courtesy client after 24hr if client has not reconnected.

. do not allow expired client to become courtesy client if there are
  waiters for client's locks.

. modify client_info_show to show courtesy client and seconds from
  last renew.

. fix a problem with NFSv4.1 server where the it keeps returning
  SEQ4_STATUS_CB_PATH_DOWN in the successful SEQUENCE reply, after
  the courtesy client reconnects, causing the client to keep sending
  BCTS requests to server.

v3 patch includes:

. modified posix_test_lock to check and resolve conflict locks
  to handle NLM TEST and NFSv4 LOCKT requests.

. separate out fix for back channel stuck in SEQ4_STATUS_CB_PATH_DOWN.

v4 patch includes:

. rework nfsd_check_courtesy to avoid dead lock of fl_lock and client_lock
  by asking the laudromat thread to destroy the courtesy client.

. handle NFSv4 share reservation conflicts with courtesy client. This
  includes conflicts between access mode and deny mode and vice versa.

. drop the patch for back channel stuck in SEQ4_STATUS_CB_PATH_DOWN.

v5 patch includes:

. fix recursive locking of file_rwsem from posix_lock_file. 

. retest with LOCKDEP enabled.

v6 patch includes:

. merge witn 5.15-rc7

. fix a bug in nfs4_check_deny_bmap that did not check for matched
  nfs4_file before checking for access/deny conflict. This bug causes
  pynfs OPEN18 to fail since the server taking too long to release
  lots of un-conflict clients' state.

. enhance share reservation conflict handler to handle case where
  a large number of conflict courtesy clients need to be expired.
  The 1st 100 clients are expired synchronously and the rest are
  expired in the background by the laundromat and NFS4ERR_DELAY
  is returned to the NFS client. This is needed to prevent the
  NFS client from timing out waiting got the reply.

v7 patch includes:

. Fix race condition in posix_test_lock and posix_lock_inode after
  dropping spinlock.

. Enhance nfsd4_fl_expire_lock to work with with new lm_expire_lock
  callback

. Always resolve share reservation conflicts asynchrously.

. Fix bug in nfs4_laundromat where spinlock is not used when
  scanning cl_ownerstr_hashtbl.

. Fix bug in nfs4_laundromat where idr_get_next was called
  with incorrect 'id'. 

. Merge nfs4_destroy_courtesy_client into nfsd4_fl_expire_lock.

v8 patch includes:

. Fix warning in nfsd4_fl_expire_lock reported by test robot.

v9 patch includes:

. Simplify lm_expire_lock API by (1) remove the 'testonly' flag
  and (2) specifying return value as true/false to indicate
  whether conflict was succesfully resolved.

. Rework nfsd4_fl_expire_lock to mark client with
  NFSD4_DESTROY_COURTESY_CLIENT then tell the laundromat to expire
  the client in the background.

. Add a spinlock in nfs4_client to synchronize access to the
  NFSD4_COURTESY_CLIENT and NFSD4_DESTROY_COURTESY_CLIENT flag to
  handle race conditions when resolving lock and share reservation
  conflict.

. Courtesy client that was marked as NFSD4_DESTROY_COURTESY_CLIENT
  are now consisdered 'dead', waiting for the laundromat to expire
  it. This client is no longer allowed to use its states if it
  reconnects before the laundromat finishes expiring the client.

  For v4.1 client, the detection is done in the processing of the
  SEQUENCE op and returns NFS4ERR_BAD_SESSION to force the client
  to re-establish new clientid and session.
  For v4.0 client, the detection is done in the processing of the
  RENEW and state-related ops and return NFS4ERR_EXPIRE to force
  the client to re-establish new clientid.

v10 patch includes:

  Resolve deadlock in v9 by avoiding getting cl_client and
  cl_cs_lock together. The laundromat needs to determine whether
  the expired client has any state and also has no blockers on
  its locks. Both of these conditions are allowed to change after
  the laundromat transits an expired client to courtesy client.
  When this happens, the laundromat will detect it on the next
  run and and expire the courtesy client.

  Remove client persistent record before marking it as COURTESY_CLIENT
  and add client persistent record before clearing the COURTESY_CLIENT
  flag to allow the courtesy client to transist to normal client to
  continue to use its state.

  Lock/delegation/share reversation conflict with courtesy client is
  resolved by marking the courtesy client as DESTROY_COURTESY_CLIENT,
  effectively disable it, then allow the current request to proceed
  immediately.
  
  Courtesy client marked as DESTROY_COURTESY_CLIENT is not allowed
  to reconnect to reuse itsstate. It is expired by the laundromat
  asynchronously in the background.

  Move processing of expired clients from nfs4_laudromat to a
  separate function, nfs4_get_client_reaplist, that creates the
  reaplist and also to process courtesy clients.

  Update Documentation/filesystems/locking.rst to include new
  lm_lock_conflict call.

  Modify leases_conflict to call lm_breaker_owns_lease only if
  there is real conflict.  This is to allow the lock manager to
  resolve the delegation conflict if possible.

v11 patch includes:

  Add comment for lm_lock_conflict callback.

  Replace static const courtesy_client_expiry with macro.

  Remove courtesy_clnt argument from find_in_sessionid_hashtbl.
  Callers use nfs4_client->cl_cs_client boolean to determined if
  it's the courtesy client and take appropriate actions.

  Rename NFSD4_COURTESY_CLIENT and NFSD4_DESTROY_COURTESY_CLIENT
  with NFSD4_CLIENT_COURTESY and NFSD4_CLIENT_DESTROY_COURTESY.

v12 patch includes:

  Remove unnecessary comment in nfs4_get_client_reaplist.

  Replace nfs4_client->cl_cs_client boolean with
  NFSD4_CLIENT_COURTESY_CLNT flag.

  Remove courtesy_clnt argument from find_client_in_id_table and
  find_clp_in_name_tree. Callers use NFSD4_CLIENT_COURTESY_CLNT to
  determined if it's the courtesy client and take appropriate actions.

v13 patch includes:

  Merge with 5.17-rc3.

  Cleanup Documentation/filesystems/locking.rst: replace i_lock
  with flc_lock, update API's that use flc_lock.

  Rename lm_lock_conflict to lm_lock_expired().

  Remove comment of lm_lock_expired API in lock_manager_operations.
  Same information is in patch description.

  Update commit messages of 4/4.

  Add some comment for NFSD4_CLIENT_COURTESY_CLNT.

  Add nfsd4_discard_courtesy_clnt() to eliminate duplicate code of
  discarding courtesy client; setting NFSD4_DESTROY_COURTESY_CLIENT.

v14 patch includes:

. merge with Chuck's public for-next branch.

. remove courtesy_client_expiry, use client's last renew time.

. simplify comment of nfs4_check_access_deny_bmap.

. add comment about race condition in nfs4_get_client_reaplist.

. add list_del when walking cslist in nfs4_get_client_reaplist.

. remove duplicate INIT_LIST_HEAD(&reaplist) from nfs4_laundromat

. Modify find_confirmed_client and find_confirmed_client_by_name
  to detect courtesy client and destroy it.

. refactor lookup_clientid to use find_client_in_id_table
  directly instead of find_confirmed_client.

. refactor nfsd4_setclientid to call find_clp_in_name_tree
  directly instead of find_confirmed_client_by_name.

. remove comment of NFSD4_CLIENT_COURTESY.

. replace NFSD4_CLIENT_DESTROY_COURTESY with NFSD4_CLIENT_EXPIRED.

. replace NFSD4_CLIENT_COURTESY_CLNT with NFSD4_CLIENT_RECONNECTED.

v15 patch includes:

. add helper locks_has_blockers_locked in fs.h to check for
  lock blockers

. rename nfs4_conflict_clients to nfs4_resolve_deny_conflicts_locked

. update nfs4_upgrade_open() to handle courtesy clients.

. add helper nfs4_check_and_expire_courtesy_client and
  nfs4_is_courtesy_client_expired to deduplicate some code.

. update nfs4_anylock_blocker:
   . replace list_for_each_entry_safe with list_for_each_entry
   . break nfs4_anylock_blocker into 2 smaller functions.

. update nfs4_get_client_reaplist:
   . remove unnecessary commets
   . acquire cl_cs_lock before setting NFSD4_CLIENT_COURTESY flag

. update client_info_show to show 'time since last renew: 00:00:38'
  instead of 'seconds from last renew: 38'.

[PATCH RFC v15 01/11] fs/lock: add helper locks_any_blockers to check for blockers

[Dai Ngo]

Add helper locks_any_blockers to check if there is any blockers
for a file_lock.

Signed-off-by: Dai Ngo <dai.ngo@oracle.com>
---
 include/linux/fs.h | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/include/linux/fs.h b/include/linux/fs.h
index 831b20430d6e..7f5756bfcc13 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1200,6 +1200,11 @@ extern void lease_unregister_notifier(struct notifier_block *);
 struct files_struct;
 extern void show_fd_locks(struct seq_file *f,
 			 struct file *filp, struct files_struct *files);
+
+static inline bool locks_has_blockers_locked(struct file_lock *lck)
+{
+	return !list_empty(&lck->fl_blocked_requests);
+}
 #else /* !CONFIG_FILE_LOCKING */
 static inline int fcntl_getlk(struct file *file, unsigned int cmd,
 			      struct flock __user *user)
@@ -1335,6 +1340,11 @@ static inline int lease_modify(struct file_lock *fl, int arg,
 struct files_struct;
 static inline void show_fd_locks(struct seq_file *f,
 			struct file *filp, struct files_struct *files) {}
+
+static inline bool locks_has_blockers_locked(struct file_lock *lck)
+{
+	return false;
+}
 #endif /* !CONFIG_FILE_LOCKING */
 
 static inline struct inode *file_inode(const struct file *f)
-- 
2.9.5

[PATCH RFC v15 02/11] NFSD: Add client flags, macro and spinlock to support courteous server

[Dai Ngo]

Add flags to track a client's lease state after the client fails to
renew its lease. Add macro for courtesy client expire time. Add spinlock
to synchronize access to these flags. Modify alloc_client to initialize
these fields.

Signed-off-by: Dai Ngo <dai.ngo@oracle.com>
---
 fs/nfsd/nfs4state.c | 2 ++
 fs/nfsd/nfsd.h      | 1 +
 fs/nfsd/state.h     | 6 ++++++
 3 files changed, 9 insertions(+)

diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 234e852fcdfa..a65d59510681 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -2009,12 +2009,14 @@ static struct nfs4_client *alloc_client(struct xdr_netobj name)
 	INIT_LIST_HEAD(&clp->cl_delegations);
 	INIT_LIST_HEAD(&clp->cl_lru);
 	INIT_LIST_HEAD(&clp->cl_revoked);
+	INIT_LIST_HEAD(&clp->cl_cs_list);
 #ifdef CONFIG_NFSD_PNFS
 	INIT_LIST_HEAD(&clp->cl_lo_states);
 #endif
 	INIT_LIST_HEAD(&clp->async_copies);
 	spin_lock_init(&clp->async_lock);
 	spin_lock_init(&clp->cl_lock);
+	spin_lock_init(&clp->cl_cs_lock);
 	rpc_init_wait_queue(&clp->cl_cb_waitq, "Backchannel slot table");
 	return clp;
 err_no_hashtbl:
diff --git a/fs/nfsd/nfsd.h b/fs/nfsd/nfsd.h
index 4fc1fd639527..23996c6ca75e 100644
--- a/fs/nfsd/nfsd.h
+++ b/fs/nfsd/nfsd.h
@@ -336,6 +336,7 @@ void		nfsd_lockd_shutdown(void);
 #define COMPOUND_ERR_SLACK_SPACE	16     /* OP_SETATTR */
 
 #define NFSD_LAUNDROMAT_MINTIMEOUT      1   /* seconds */
+#define	NFSD_COURTESY_CLIENT_TIMEOUT	(24 * 60 * 60)	/* seconds */
 
 /*
  * The following attributes are currently not supported by the NFSv4 server:
diff --git a/fs/nfsd/state.h b/fs/nfsd/state.h
index 95457cfd37fc..8cbd3b69a584 100644
--- a/fs/nfsd/state.h
+++ b/fs/nfsd/state.h
@@ -343,6 +343,9 @@ struct nfs4_client {
 #define NFSD4_CLIENT_RECLAIM_COMPLETE	(3)	/* reclaim_complete done */
 #define NFSD4_CLIENT_CONFIRMED		(4)	/* client is confirmed */
 #define NFSD4_CLIENT_UPCALL_LOCK	(5)	/* upcall serialization */
+#define	NFSD4_CLIENT_COURTESY		(6)
+#define	NFSD4_CLIENT_EXPIRED		(7)
+#define	NFSD4_CLIENT_RECONNECTED	(8)
 #define NFSD4_CLIENT_CB_FLAG_MASK	(1 << NFSD4_CLIENT_CB_UPDATE | \
 					 1 << NFSD4_CLIENT_CB_KILL)
 	unsigned long		cl_flags;
@@ -385,6 +388,9 @@ struct nfs4_client {
 	struct list_head	async_copies;	/* list of async copies */
 	spinlock_t		async_lock;	/* lock for async copies */
 	atomic_t		cl_cb_inflight;	/* Outstanding callbacks */
+
+	spinlock_t		cl_cs_lock;
+	struct list_head	cl_cs_list;
 };
 
 /* struct nfs4_client_reset
-- 
2.9.5

[PATCH RFC v15 03/11] NFSD: Add lm_lock_expired call out

[Dai Ngo]

Add callout function nfsd4_lm_lock_expired for lm_lock_expired.
If lock request has conflict with courtesy client then expire the
courtesy client and return no conflict to caller.

Signed-off-by: Dai Ngo <dai.ngo@oracle.com>
---
 fs/nfsd/nfs4state.c | 37 +++++++++++++++++++++++++++++++++++++
 1 file changed, 37 insertions(+)

diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index a65d59510681..583ac807e98d 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -6578,10 +6578,47 @@ nfsd4_lm_notify(struct file_lock *fl)
 	}
 }
 
+/**
+ * nfsd4_lm_lock_expired - check if lock conflict can be resolved.
+ *
+ * @fl: pointer to file_lock with a potential conflict
+ * Return values:
+ *   %false: real conflict, lock conflict can not be resolved.
+ *   %true: no conflict, lock conflict was resolved.
+ *
+ * Note that this function is called while the flc_lock is held.
+ */
+static bool
+nfsd4_lm_lock_expired(struct file_lock *fl)
+{
+	struct nfs4_lockowner *lo;
+	struct nfs4_client *clp;
+	bool rc = false;
+
+	if (!fl)
+		return false;
+	lo = (struct nfs4_lockowner *)fl->fl_owner;
+	clp = lo->lo_owner.so_client;
+
+	/* need to sync with courtesy client trying to reconnect */
+	spin_lock(&clp->cl_cs_lock);
+	if (test_bit(NFSD4_CLIENT_EXPIRED, &clp->cl_flags))
+		rc = true;
+	else {
+		if (test_bit(NFSD4_CLIENT_COURTESY, &clp->cl_flags)) {
+			set_bit(NFSD4_CLIENT_EXPIRED, &clp->cl_flags);
+			rc =  true;
+		}
+	}
+	spin_unlock(&clp->cl_cs_lock);
+	return rc;
+}
+
 static const struct lock_manager_operations nfsd_posix_mng_ops  = {
 	.lm_notify = nfsd4_lm_notify,
 	.lm_get_owner = nfsd4_lm_get_owner,
 	.lm_put_owner = nfsd4_lm_put_owner,
+	.lm_lock_expired = nfsd4_lm_lock_expired,
 };
 
 static inline void
-- 
2.9.5

[PATCH RFC v15 04/11] NFSD: Update nfsd_breaker_owns_lease() to handle courtesy clients

[Dai Ngo]

Update nfsd_breaker_owns_lease() to handle delegation conflict
with courtesy clients. If conflict was caused courtesy client
then discard the courtesy client by setting CLIENT_EXPIRED and
return conflict resolved. Client with CLIENT_EXPIRED is expired
by the laundromat.

Signed-off-by: Dai Ngo <dai.ngo@oracle.com>
---
 fs/nfsd/nfs4state.c | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 583ac807e98d..40a357fd1a14 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -4727,6 +4727,24 @@ static bool nfsd_breaker_owns_lease(struct file_lock *fl)
 	struct svc_rqst *rqst;
 	struct nfs4_client *clp;
 
+	clp = dl->dl_stid.sc_client;
+	/*
+	 * need to sync with courtesy client trying to reconnect using
+	 * the cl_cs_lock, nn->client_lock can not be used since this
+	 * function is called with the fl_lck held.
+	 */
+	spin_lock(&clp->cl_cs_lock);
+	if (test_bit(NFSD4_CLIENT_EXPIRED, &clp->cl_flags)) {
+		spin_unlock(&clp->cl_cs_lock);
+		return true;
+	}
+	if (test_bit(NFSD4_CLIENT_COURTESY, &clp->cl_flags)) {
+		set_bit(NFSD4_CLIENT_EXPIRED, &clp->cl_flags);
+		spin_unlock(&clp->cl_cs_lock);
+		return true;
+	}
+	spin_unlock(&clp->cl_cs_lock);
+
 	if (!i_am_nfsd())
 		return false;
 	rqst = kthread_data(current);
-- 
2.9.5

[PATCH RFC v15 05/11] NFSD: Update nfs4_get_vfs_file() to handle courtesy clients

[Dai Ngo]

Update nfs4_get_vfs_file and nfs4_upgrade_open to handle share
reservation conflict with courtesy client.

If share/access check fails with share denied then check if the
the conflict was caused by courtesy clients. If that's the case
then set CLIENT_EXPIRED flag to expire the courtesy clients and
allow nfs4_get_vfs_file to continue. Client with CLIENT_EXPIRED
is expired by the laundromat.

Signed-off-by: Dai Ngo <dai.ngo@oracle.com>
---
 fs/nfsd/nfs4state.c | 135 +++++++++++++++++++++++++++++++++++++++++++---------
 1 file changed, 113 insertions(+), 22 deletions(-)

diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 40a357fd1a14..b16f689f34c3 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -4713,21 +4713,9 @@ nfsd_break_deleg_cb(struct file_lock *fl)
 	return ret;
 }
 
-/**
- * nfsd_breaker_owns_lease - Check if lease conflict was resolved
- * @fl: Lock state to check
- *
- * Return values:
- *   %true: Lease conflict was resolved
- *   %false: Lease conflict was not resolved.
- */
-static bool nfsd_breaker_owns_lease(struct file_lock *fl)
+static bool
+nfs4_check_and_expire_courtesy_client(struct nfs4_client *clp)
 {
-	struct nfs4_delegation *dl = fl->fl_owner;
-	struct svc_rqst *rqst;
-	struct nfs4_client *clp;
-
-	clp = dl->dl_stid.sc_client;
 	/*
 	 * need to sync with courtesy client trying to reconnect using
 	 * the cl_cs_lock, nn->client_lock can not be used since this
@@ -4744,6 +4732,26 @@ static bool nfsd_breaker_owns_lease(struct file_lock *fl)
 		return true;
 	}
 	spin_unlock(&clp->cl_cs_lock);
+	return false;
+}
+
+/**
+ * nfsd_breaker_owns_lease - Check if lease conflict was resolved
+ * @fl: Lock state to check
+ *
+ * Return values:
+ *   %true: Lease conflict was resolved
+ *   %false: Lease conflict was not resolved.
+ */
+static bool nfsd_breaker_owns_lease(struct file_lock *fl)
+{
+	struct nfs4_delegation *dl = fl->fl_owner;
+	struct svc_rqst *rqst;
+	struct nfs4_client *clp;
+
+	clp = dl->dl_stid.sc_client;
+	if (nfs4_check_and_expire_courtesy_client(clp))
+		return true;
 
 	if (!i_am_nfsd())
 		return false;
@@ -4965,9 +4973,75 @@ nfsd4_truncate(struct svc_rqst *rqstp, struct svc_fh *fh,
 	return nfsd_setattr(rqstp, fh, &iattr, 0, (time64_t)0);
 }
 
+static bool
+nfs4_check_access_deny_bmap(struct nfs4_ol_stateid *stp, u32 access,
+			bool share_access)
+{
+	if (share_access) {
+		if (!stp->st_deny_bmap)
+			return false;
+
+		if ((stp->st_deny_bmap & (1 << NFS4_SHARE_DENY_BOTH)) ||
+			(access & NFS4_SHARE_ACCESS_READ &&
+				stp->st_deny_bmap & (1 << NFS4_SHARE_DENY_READ)) ||
+			(access & NFS4_SHARE_ACCESS_WRITE &&
+				stp->st_deny_bmap & (1 << NFS4_SHARE_DENY_WRITE))) {
+			return true;
+		}
+		return false;
+	}
+	if ((access & NFS4_SHARE_DENY_BOTH) ||
+		(access & NFS4_SHARE_DENY_READ &&
+			stp->st_access_bmap & (1 << NFS4_SHARE_ACCESS_READ)) ||
+		(access & NFS4_SHARE_DENY_WRITE &&
+			stp->st_access_bmap & (1 << NFS4_SHARE_ACCESS_WRITE))) {
+		return true;
+	}
+	return false;
+}
+
+/*
+ * Check whether courtesy clients have conflicting access
+ *
+ * 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:
+ *	true   - access/deny mode conflict with normal client.
+ *	false  - 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 = false;
+
+	lockdep_assert_held(&fp->fi_lock);
+	list_for_each_entry(st, &fp->fi_stateids, st_perfile) {
+		if (st->st_openstp || (st == stp && new_stp) ||
+			(!nfs4_check_access_deny_bmap(st,
+					access, share_access)))
+			continue;
+		clp = st->st_stid.sc_client;
+		if (nfs4_check_and_expire_courtesy_client(clp))
+			continue;
+		conflict = true;
+		break;
+	}
+	return conflict;
+}
+
 static __be32 nfs4_get_vfs_file(struct svc_rqst *rqstp, struct nfs4_file *fp,
 		struct svc_fh *cur_fh, struct nfs4_ol_stateid *stp,
-		struct nfsd4_open *open)
+		struct nfsd4_open *open, bool new_stp)
 {
 	struct nfsd_file *nf = NULL;
 	__be32 status;
@@ -4983,15 +5057,29 @@ static __be32 nfs4_get_vfs_file(struct svc_rqst *rqstp, struct nfs4_file *fp,
 	 */
 	status = nfs4_file_check_deny(fp, open->op_share_deny);
 	if (status != nfs_ok) {
-		spin_unlock(&fp->fi_lock);
-		goto out;
+		if (status != nfserr_share_denied) {
+			spin_unlock(&fp->fi_lock);
+			goto out;
+		}
+		if (nfs4_resolve_deny_conflicts_locked(fp, new_stp,
+				stp, open->op_share_deny, false)) {
+			spin_unlock(&fp->fi_lock);
+			goto out;
+		}
 	}
 
 	/* set access to the file */
 	status = nfs4_file_get_access(fp, open->op_share_access);
 	if (status != nfs_ok) {
-		spin_unlock(&fp->fi_lock);
-		goto out;
+		if (status != nfserr_share_denied) {
+			spin_unlock(&fp->fi_lock);
+			goto out;
+		}
+		if (nfs4_resolve_deny_conflicts_locked(fp, new_stp,
+				stp, open->op_share_access, true)) {
+			spin_unlock(&fp->fi_lock);
+			goto out;
+		}
 	}
 
 	/* Set access bits in stateid */
@@ -5042,7 +5130,7 @@ nfs4_upgrade_open(struct svc_rqst *rqstp, struct nfs4_file *fp, struct svc_fh *c
 	unsigned char old_deny_bmap = stp->st_deny_bmap;
 
 	if (!test_access(open->op_share_access, stp))
-		return nfs4_get_vfs_file(rqstp, fp, cur_fh, stp, open);
+		return nfs4_get_vfs_file(rqstp, fp, cur_fh, stp, open, false);
 
 	/* test and set deny mode */
 	spin_lock(&fp->fi_lock);
@@ -5051,7 +5139,10 @@ nfs4_upgrade_open(struct svc_rqst *rqstp, struct nfs4_file *fp, struct svc_fh *c
 		set_deny(open->op_share_deny, stp);
 		fp->fi_share_deny |=
 				(open->op_share_deny & NFS4_SHARE_DENY_BOTH);
-	}
+	} else if (status == nfserr_share_denied &&
+		!nfs4_resolve_deny_conflicts_locked(fp, false, stp,
+			open->op_share_deny, false))
+		status = nfs_ok;
 	spin_unlock(&fp->fi_lock);
 
 	if (status != nfs_ok)
@@ -5391,7 +5482,7 @@ nfsd4_process_open2(struct svc_rqst *rqstp, struct svc_fh *current_fh, struct nf
 			goto out;
 		}
 	} else {
-		status = nfs4_get_vfs_file(rqstp, fp, current_fh, stp, open);
+		status = nfs4_get_vfs_file(rqstp, fp, current_fh, stp, open, true);
 		if (status) {
 			stp->st_stid.sc_type = NFS4_CLOSED_STID;
 			release_open_stateid(stp);
-- 
2.9.5

[PATCH RFC v15 06/11] NFSD: Update find_clp_in_name_tree() to handle courtesy clients

[Dai Ngo]

Update find_clp_in_name_tree:
 . skip client with CLIENT_EXPIRED flag; discarded courtesy client.
 . if courtesy client was found then clear CLIENT_COURTESY and
   set CLIENT_RECONNECTED so callers can take appropriate action.

Update find_confirmed_client_by_name to discard the courtesy
client; set CLIENT_EXPIRED.

Update nfsd4_setclientid to expire the confirmed courtesy client
to prevent multiple confirmed clients with the same name on the
the conf_id_hashtbl list.

Signed-off-by: Dai Ngo <dai.ngo@oracle.com>
---
 fs/nfsd/nfs4state.c | 55 ++++++++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 52 insertions(+), 3 deletions(-)

diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index b16f689f34c3..f42d72a8f5ca 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -1929,6 +1929,34 @@ __find_in_sessionid_hashtbl(struct nfs4_sessionid *sessionid, struct net *net)
 	return NULL;
 }
 
+static void
+nfsd4_discard_courtesy_clnt(struct nfs4_client *clp)
+{
+	spin_lock(&clp->cl_cs_lock);
+	set_bit(NFSD4_CLIENT_EXPIRED, &clp->cl_flags);
+	spin_unlock(&clp->cl_cs_lock);
+}
+
+static bool
+nfs4_is_courtesy_client_expired(struct nfs4_client *clp)
+{
+	clear_bit(NFSD4_CLIENT_RECONNECTED, &clp->cl_flags);
+	/* need to sync with thread resolving lock/deleg conflict */
+	spin_lock(&clp->cl_cs_lock);
+	if (test_bit(NFSD4_CLIENT_EXPIRED, &clp->cl_flags)) {
+		spin_unlock(&clp->cl_cs_lock);
+		return true;
+	}
+	/*
+	 * clear CLIENT_COURTESY flag to prevent it from being
+	 * destroyed by thread trying to resolve conflicts.
+	 */
+	if (test_and_clear_bit(NFSD4_CLIENT_COURTESY, &clp->cl_flags))
+		set_bit(NFSD4_CLIENT_RECONNECTED, &clp->cl_flags);
+	spin_unlock(&clp->cl_cs_lock);
+	return false;
+}
+
 static struct nfsd4_session *
 find_in_sessionid_hashtbl(struct nfs4_sessionid *sessionid, struct net *net,
 		__be32 *ret)
@@ -2834,8 +2862,11 @@ find_clp_in_name_tree(struct xdr_netobj *name, struct rb_root *root)
 			node = node->rb_left;
 		else if (cmp < 0)
 			node = node->rb_right;
-		else
+		else {
+			if (nfs4_is_courtesy_client_expired(clp))
+				return NULL;
 			return clp;
+		}
 	}
 	return NULL;
 }
@@ -2914,8 +2945,15 @@ static bool clp_used_exchangeid(struct nfs4_client *clp)
 static struct nfs4_client *
 find_confirmed_client_by_name(struct xdr_netobj *name, struct nfsd_net *nn)
 {
+	struct nfs4_client *clp;
+
 	lockdep_assert_held(&nn->client_lock);
-	return find_clp_in_name_tree(name, &nn->conf_name_tree);
+	clp = find_clp_in_name_tree(name, &nn->conf_name_tree);
+	if (clp && test_bit(NFSD4_CLIENT_RECONNECTED, &clp->cl_flags)) {
+		nfsd4_discard_courtesy_clnt(clp);
+		clp = NULL;
+	}
+	return clp;
 }
 
 static struct nfs4_client *
@@ -4032,12 +4070,19 @@ nfsd4_setclientid(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
 	struct nfs4_client	*unconf = NULL;
 	__be32 			status;
 	struct nfsd_net		*nn = net_generic(SVC_NET(rqstp), nfsd_net_id);
+	struct nfs4_client	*cclient = NULL;
 
 	new = create_client(clname, rqstp, &clverifier);
 	if (new == NULL)
 		return nfserr_jukebox;
 	spin_lock(&nn->client_lock);
-	conf = find_confirmed_client_by_name(&clname, nn);
+	/* find confirmed client by name */
+	conf = find_clp_in_name_tree(&clname, &nn->conf_name_tree);
+	if (conf && test_bit(NFSD4_CLIENT_RECONNECTED, &conf->cl_flags)) {
+		cclient = conf;
+		conf = NULL;
+	}
+
 	if (conf && client_has_state(conf)) {
 		status = nfserr_clid_inuse;
 		if (clp_used_exchangeid(conf))
@@ -4068,7 +4113,11 @@ nfsd4_setclientid(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
 	new = NULL;
 	status = nfs_ok;
 out:
+	if (cclient)
+		unhash_client_locked(cclient);
 	spin_unlock(&nn->client_lock);
+	if (cclient)
+		expire_client(cclient);
 	if (new)
 		free_client(new);
 	if (unconf) {
-- 
2.9.5

[PATCH RFC v15 07/11] NFSD: Update find_in_sessionid_hashtbl() to handle courtesy clients

[Dai Ngo]

Update find_in_sessionid_hashtbl to:
 . skip client with CLIENT_EXPIRED flag; discarded courtesy client.
 . if courtesy client was found then clear CLIENT_COURTESY and
   set CLIENT_RECONNECTED so callers can take appropriate action.

Update nfsd4_sequence and nfsd4_bind_conn_to_session to create client
record for client with CLIENT_RECONNECTED set.

Update nfsd4_destroy_session to discard client with CLIENT_RECONNECTED
set.

Signed-off-by: Dai Ngo <dai.ngo@oracle.com>
---
 fs/nfsd/nfs4state.c | 34 ++++++++++++++++++++++++++++++++--
 1 file changed, 32 insertions(+), 2 deletions(-)

diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index f42d72a8f5ca..34a59c6f446c 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -1963,13 +1963,22 @@ find_in_sessionid_hashtbl(struct nfs4_sessionid *sessionid, struct net *net,
 {
 	struct nfsd4_session *session;
 	__be32 status = nfserr_badsession;
+	struct nfs4_client *clp;
 
 	session = __find_in_sessionid_hashtbl(sessionid, net);
 	if (!session)
 		goto out;
+	clp = session->se_client;
+	if (clp && nfs4_is_courtesy_client_expired(clp)) {
+		session = NULL;
+		goto out;
+	}
 	status = nfsd4_get_session_locked(session);
-	if (status)
+	if (status) {
 		session = NULL;
+		if (clp && test_bit(NFSD4_CLIENT_COURTESY, &clp->cl_flags))
+			nfsd4_discard_courtesy_clnt(clp);
+	}
 out:
 	*ret = status;
 	return session;
@@ -3671,6 +3680,7 @@ __be32 nfsd4_bind_conn_to_session(struct svc_rqst *rqstp,
 	struct nfsd4_session *session;
 	struct net *net = SVC_NET(rqstp);
 	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
+	struct nfs4_client *clp;
 
 	if (!nfsd4_last_compound_op(rqstp))
 		return nfserr_not_only_op;
@@ -3703,6 +3713,13 @@ __be32 nfsd4_bind_conn_to_session(struct svc_rqst *rqstp,
 	nfsd4_init_conn(rqstp, conn, session);
 	status = nfs_ok;
 out:
+	clp = session->se_client;
+	if (test_bit(NFSD4_CLIENT_RECONNECTED, &clp->cl_flags)) {
+		if (status == nfs_ok)
+			nfsd4_client_record_create(clp);
+		else
+			nfsd4_discard_courtesy_clnt(clp);
+	}
 	nfsd4_put_session(session);
 out_no_session:
 	return status;
@@ -3725,6 +3742,7 @@ nfsd4_destroy_session(struct svc_rqst *r, struct nfsd4_compound_state *cstate,
 	int ref_held_by_me = 0;
 	struct net *net = SVC_NET(r);
 	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
+	struct nfs4_client *clp;
 
 	status = nfserr_not_only_op;
 	if (nfsd4_compound_in_session(cstate, sessionid)) {
@@ -3737,6 +3755,12 @@ nfsd4_destroy_session(struct svc_rqst *r, struct nfsd4_compound_state *cstate,
 	ses = find_in_sessionid_hashtbl(sessionid, net, &status);
 	if (!ses)
 		goto out_client_lock;
+	clp = ses->se_client;
+	if (test_bit(NFSD4_CLIENT_RECONNECTED, &clp->cl_flags)) {
+		status = nfserr_badsession;
+		nfsd4_discard_courtesy_clnt(clp);
+		goto out_put_session;
+	}
 	status = nfserr_wrong_cred;
 	if (!nfsd4_mach_creds_match(ses->se_client, r))
 		goto out_put_session;
@@ -3841,7 +3865,7 @@ nfsd4_sequence(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
 	struct nfsd4_compoundres *resp = rqstp->rq_resp;
 	struct xdr_stream *xdr = resp->xdr;
 	struct nfsd4_session *session;
-	struct nfs4_client *clp;
+	struct nfs4_client *clp = NULL;
 	struct nfsd4_slot *slot;
 	struct nfsd4_conn *conn;
 	__be32 status;
@@ -3951,6 +3975,12 @@ nfsd4_sequence(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
 	if (conn)
 		free_conn(conn);
 	spin_unlock(&nn->client_lock);
+	if (clp && test_bit(NFSD4_CLIENT_RECONNECTED, &clp->cl_flags)) {
+		if (status == nfs_ok)
+			nfsd4_client_record_create(clp);
+		else
+			nfsd4_discard_courtesy_clnt(clp);
+	}
 	return status;
 out_put_session:
 	nfsd4_put_session_locked(session);
-- 
2.9.5

[PATCH RFC v15 08/11] NFSD: Update find_client_in_id_table() to handle courtesy clients

[Dai Ngo]

Update find_client_in_id_table to:
 . skip client with CLIENT_EXPIRED; discarded courtesy client
 . if courtesy client was found then clear CLIENT_COURTESY and set
   CLIENT_RECONNECTED flag so callers can take appropriate action.

Update find_confirmed_client to discard courtesy client.
Update lookup_clientid to call find_client_in_id_table directly.
Update set_client to create client record for courtesy client.
Update find_cpntf_state to discard courtesy client.

Signed-off-by: Dai Ngo <dai.ngo@oracle.com>
---
 fs/nfsd/nfs4state.c | 22 ++++++++++++++++++++--
 1 file changed, 20 insertions(+), 2 deletions(-)

diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 34a59c6f446c..4a5276696afe 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -2921,6 +2921,8 @@ find_client_in_id_table(struct list_head *tbl, clientid_t *clid, bool sessions)
 		if (same_clid(&clp->cl_clientid, clid)) {
 			if ((bool)clp->cl_minorversion != sessions)
 				return NULL;
+			if (nfs4_is_courtesy_client_expired(clp))
+				continue;
 			renew_client_locked(clp);
 			return clp;
 		}
@@ -2932,9 +2934,15 @@ static struct nfs4_client *
 find_confirmed_client(clientid_t *clid, bool sessions, struct nfsd_net *nn)
 {
 	struct list_head *tbl = nn->conf_id_hashtbl;
+	struct nfs4_client *clp;
 
 	lockdep_assert_held(&nn->client_lock);
-	return find_client_in_id_table(tbl, clid, sessions);
+	clp = find_client_in_id_table(tbl, clid, sessions);
+	if (clp && test_bit(NFSD4_CLIENT_RECONNECTED, &clp->cl_flags)) {
+		nfsd4_discard_courtesy_clnt(clp);
+		clp = NULL;
+	}
+	return clp;
 }
 
 static struct nfs4_client *
@@ -4873,9 +4881,10 @@ static struct nfs4_client *lookup_clientid(clientid_t *clid, bool sessions,
 						struct nfsd_net *nn)
 {
 	struct nfs4_client *found;
+	struct list_head *tbl = nn->conf_id_hashtbl;
 
 	spin_lock(&nn->client_lock);
-	found = find_confirmed_client(clid, sessions, nn);
+	found = find_client_in_id_table(tbl, clid, sessions);
 	if (found)
 		atomic_inc(&found->cl_rpc_users);
 	spin_unlock(&nn->client_lock);
@@ -4900,6 +4909,8 @@ static __be32 set_client(clientid_t *clid,
 	cstate->clp = lookup_clientid(clid, false, nn);
 	if (!cstate->clp)
 		return nfserr_expired;
+	if (test_bit(NFSD4_CLIENT_RECONNECTED, &cstate->clp->cl_flags))
+		nfsd4_client_record_create(cstate->clp);
 	return nfs_ok;
 }
 
@@ -6219,6 +6230,13 @@ static __be32 find_cpntf_state(struct nfsd_net *nn, stateid_t *st,
 	found = lookup_clientid(&cps->cp_p_clid, true, nn);
 	if (!found)
 		goto out;
+	if (test_bit(NFSD4_CLIENT_RECONNECTED, &found->cl_flags)) {
+		nfsd4_discard_courtesy_clnt(found);
+		if (atomic_dec_and_lock(&found->cl_rpc_users,
+				&nn->client_lock))
+			spin_unlock(&nn->client_lock);
+		goto out;
+	}
 
 	*stid = find_stateid_by_type(found, &cps->cp_p_stateid,
 			NFS4_DELEG_STID|NFS4_OPEN_STID|NFS4_LOCK_STID);
-- 
2.9.5

[PATCH RFC v15 09/11] NFSD: Refactor nfsd4_laundromat()

[Dai Ngo]

Extract a bit of logic that is about to be expanded to handle
courtesy clients.

Signed-off-by: Dai Ngo <dai.ngo@oracle.com>
---
 fs/nfsd/nfs4state.c | 33 +++++++++++++++++++++------------
 1 file changed, 21 insertions(+), 12 deletions(-)

diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 4a5276696afe..9f58ad22d4c9 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -5806,6 +5806,26 @@ static void nfsd4_ssc_expire_umount(struct nfsd_net *nn)
 }
 #endif
 
+static void
+nfs4_get_client_reaplist(struct nfsd_net *nn, struct list_head *reaplist,
+				struct laundry_time *lt)
+{
+	struct list_head *pos, *next;
+	struct nfs4_client *clp;
+
+	INIT_LIST_HEAD(reaplist);
+	spin_lock(&nn->client_lock);
+	list_for_each_safe(pos, next, &nn->client_lru) {
+		clp = list_entry(pos, struct nfs4_client, cl_lru);
+		if (!state_expired(lt, clp->cl_time))
+			break;
+		if (mark_client_expired_locked(clp))
+			continue;
+		list_add(&clp->cl_lru, reaplist);
+	}
+	spin_unlock(&nn->client_lock);
+}
+
 static time64_t
 nfs4_laundromat(struct nfsd_net *nn)
 {
@@ -5828,7 +5848,6 @@ nfs4_laundromat(struct nfsd_net *nn)
 		goto out;
 	}
 	nfsd4_end_grace(nn);
-	INIT_LIST_HEAD(&reaplist);
 
 	spin_lock(&nn->s2s_cp_lock);
 	idr_for_each_entry(&nn->s2s_cp_stateids, cps_t, i) {
@@ -5838,17 +5857,7 @@ nfs4_laundromat(struct nfsd_net *nn)
 			_free_cpntf_state_locked(nn, cps);
 	}
 	spin_unlock(&nn->s2s_cp_lock);
-
-	spin_lock(&nn->client_lock);
-	list_for_each_safe(pos, next, &nn->client_lru) {
-		clp = list_entry(pos, struct nfs4_client, cl_lru);
-		if (!state_expired(&lt, clp->cl_time))
-			break;
-		if (mark_client_expired_locked(clp))
-			continue;
-		list_add(&clp->cl_lru, &reaplist);
-	}
-	spin_unlock(&nn->client_lock);
+	nfs4_get_client_reaplist(nn, &reaplist, &lt);
 	list_for_each_safe(pos, next, &reaplist) {
 		clp = list_entry(pos, struct nfs4_client, cl_lru);
 		trace_nfsd_clid_purged(&clp->cl_clientid);
-- 
2.9.5

[PATCH RFC v15 10/11] NFSD: Update laundromat to handle courtesy clients

[Dai Ngo]

Add nfs4_anylock_blocker and nfs4_lockowner_has_blockers to check
if an expired client has any lock blockers

Update nfs4_get_client_reaplist to:
 . add discarded courtesy client; client marked with CLIENT_EXPIRED,
   to reaplist.
 . detect if expired client still has state and no blockers then
   transit it to courtesy client by setting CLIENT_COURTESY flag
   and removing the client record.

Signed-off-by: Dai Ngo <dai.ngo@oracle.com>
---
 fs/nfsd/nfs4state.c | 103 +++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 101 insertions(+), 2 deletions(-)

diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 9f58ad22d4c9..bced09014e6b 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -5806,24 +5806,116 @@ static void nfsd4_ssc_expire_umount(struct nfsd_net *nn)
 }
 #endif
 
+/* Check if any lock belongs to this lockowner has any blockers */
+static bool
+nfs4_lockowner_has_blockers(struct nfs4_lockowner *lo)
+{
+	struct file_lock_context *ctx;
+	struct nfs4_ol_stateid *stp;
+	struct nfs4_file *nf;
+	struct file_lock *fl;
+
+	list_for_each_entry(stp, &lo->lo_owner.so_stateids, st_perstateowner) {
+		nf = stp->st_stid.sc_file;
+		ctx = nf->fi_inode->i_flctx;
+		if (!ctx)
+			continue;
+		spin_lock(&ctx->flc_lock);
+		list_for_each_entry(fl, &ctx->flc_posix, fl_list) {
+			if (fl->fl_owner != lo)
+				continue;
+			if (locks_has_blockers_locked(fl)) {
+				spin_unlock(&ctx->flc_lock);
+				return true;
+			}
+		}
+		spin_unlock(&ctx->flc_lock);
+	}
+	return false;
+}
+
+static bool
+nfs4_anylock_blockers(struct nfs4_client *clp)
+{
+	int i;
+	struct nfs4_stateowner *so;
+	struct nfs4_lockowner *lo;
+
+	spin_lock(&clp->cl_lock);
+	for (i = 0; i < OWNER_HASH_SIZE; i++) {
+		list_for_each_entry(so, &clp->cl_ownerstr_hashtbl[i],
+				so_strhash) {
+			if (so->so_is_open_owner)
+				continue;
+			lo = lockowner(so);
+			if (nfs4_lockowner_has_blockers(lo)) {
+				spin_unlock(&clp->cl_lock);
+				return true;
+			}
+		}
+	}
+	spin_unlock(&clp->cl_lock);
+	return false;
+}
+
 static void
 nfs4_get_client_reaplist(struct nfsd_net *nn, struct list_head *reaplist,
 				struct laundry_time *lt)
 {
 	struct list_head *pos, *next;
 	struct nfs4_client *clp;
+	bool cour;
+	struct list_head cslist;
 
 	INIT_LIST_HEAD(reaplist);
+	INIT_LIST_HEAD(&cslist);
 	spin_lock(&nn->client_lock);
 	list_for_each_safe(pos, next, &nn->client_lru) {
 		clp = list_entry(pos, struct nfs4_client, cl_lru);
 		if (!state_expired(lt, clp->cl_time))
 			break;
-		if (mark_client_expired_locked(clp))
+
+		if (!client_has_state(clp))
+			goto exp_client;
+
+		if (test_bit(NFSD4_CLIENT_EXPIRED, &clp->cl_flags))
+			goto exp_client;
+		cour = test_bit(NFSD4_CLIENT_COURTESY, &clp->cl_flags);
+		if (cour && ktime_get_boottime_seconds() >=
+				(clp->cl_time + NFSD_COURTESY_CLIENT_TIMEOUT))
+			goto exp_client;
+		if (nfs4_anylock_blockers(clp)) {
+exp_client:
+			if (mark_client_expired_locked(clp))
+				continue;
+			list_add(&clp->cl_lru, reaplist);
 			continue;
-		list_add(&clp->cl_lru, reaplist);
+		}
+		if (!cour) {
+			spin_lock(&clp->cl_cs_lock);
+			set_bit(NFSD4_CLIENT_COURTESY, &clp->cl_flags);
+			spin_unlock(&clp->cl_cs_lock);
+			list_add(&clp->cl_cs_list, &cslist);
+		}
 	}
 	spin_unlock(&nn->client_lock);
+
+	while (!list_empty(&cslist)) {
+		clp = list_first_entry(&cslist, struct nfs4_client, cl_cs_list);
+		list_del_init(&clp->cl_cs_list);
+		spin_lock(&clp->cl_cs_lock);
+		/*
+		 * Client might have re-connected. Make sure it's
+		 * still in courtesy state before removing its record.
+		 */
+		if (test_bit(NFSD4_CLIENT_EXPIRED, &clp->cl_flags) ||
+			!test_bit(NFSD4_CLIENT_COURTESY, &clp->cl_flags)) {
+			spin_unlock(&clp->cl_cs_lock);
+			continue;
+		}
+		spin_unlock(&clp->cl_cs_lock);
+		nfsd4_client_record_remove(clp);
+	}
 }
 
 static time64_t
@@ -5869,6 +5961,13 @@ nfs4_laundromat(struct nfsd_net *nn)
 		dp = list_entry (pos, struct nfs4_delegation, dl_recall_lru);
 		if (!state_expired(&lt, dp->dl_time))
 			break;
+		spin_lock(&clp->cl_cs_lock);
+		if (test_bit(NFSD4_CLIENT_COURTESY, &clp->cl_flags)) {
+			set_bit(NFSD4_CLIENT_EXPIRED, &clp->cl_flags);
+			spin_unlock(&clp->cl_cs_lock);
+			continue;
+		}
+		spin_unlock(&clp->cl_cs_lock);
 		WARN_ON(!unhash_delegation_locked(dp));
 		list_add(&dp->dl_recall_lru, &reaplist);
 	}
-- 
2.9.5

[PATCH RFC v15 11/11] NFSD: Show state of courtesy clients in client info

[Dai Ngo]

Update client_info_show to show state of courtesy client
and time since last renew.

Signed-off-by: Dai Ngo <dai.ngo@oracle.com>
---
 fs/nfsd/nfs4state.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index bced09014e6b..ed14e0b54537 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -2439,7 +2439,8 @@ static int client_info_show(struct seq_file *m, void *v)
 {
 	struct inode *inode = m->private;
 	struct nfs4_client *clp;
-	u64 clid;
+	u64 clid, hrs;
+	u32 mins, secs;
 
 	clp = get_nfsdfs_clp(inode);
 	if (!clp)
@@ -2451,6 +2452,12 @@ static int client_info_show(struct seq_file *m, void *v)
 		seq_puts(m, "status: confirmed\n");
 	else
 		seq_puts(m, "status: unconfirmed\n");
+	seq_printf(m, "courtesy client: %s\n",
+		test_bit(NFSD4_CLIENT_COURTESY, &clp->cl_flags) ? "yes" : "no");
+	hrs = div_u64_rem(ktime_get_boottime_seconds() - clp->cl_time,
+				3600, &secs);
+	mins = div_u64_rem((u64)secs, 60, &secs);
+	seq_printf(m, "time since last renew: %02ld:%02d:%02d\n", hrs, mins, secs);
 	seq_printf(m, "name: ");
 	seq_quote_mem(m, clp->cl_name.data, clp->cl_name.len);
 	seq_printf(m, "\nminor version: %d\n", clp->cl_minorversion);
-- 
2.9.5

Re: [PATCH RFC v15 11/11] NFSD: Show state of courtesy clients in client info

[Chuck Lever III]

> On Mar 4, 2022, at 7:37 PM, Dai Ngo <dai.ngo@oracle.com> wrote:
> 
> Update client_info_show to show state of courtesy client
> and time since last renew.
> 
> Signed-off-by: Dai Ngo <dai.ngo@oracle.com>
> ---
> fs/nfsd/nfs4state.c | 9 ++++++++-
> 1 file changed, 8 insertions(+), 1 deletion(-)
> 
> diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
> index bced09014e6b..ed14e0b54537 100644
> --- a/fs/nfsd/nfs4state.c
> +++ b/fs/nfsd/nfs4state.c
> @@ -2439,7 +2439,8 @@ static int client_info_show(struct seq_file *m, void *v)
> {
> 	struct inode *inode = m->private;
> 	struct nfs4_client *clp;
> -	u64 clid;
> +	u64 clid, hrs;
> +	u32 mins, secs;
> 
> 	clp = get_nfsdfs_clp(inode);
> 	if (!clp)
> @@ -2451,6 +2452,12 @@ static int client_info_show(struct seq_file *m, void *v)
> 		seq_puts(m, "status: confirmed\n");
> 	else
> 		seq_puts(m, "status: unconfirmed\n");
> +	seq_printf(m, "courtesy client: %s\n",
> +		test_bit(NFSD4_CLIENT_COURTESY, &clp->cl_flags) ? "yes" : "no");

I'm wondering if it would be more economical to combine this
output with the status output just before it so we have only
one of:

	seq_puts(m, "status: unconfirmed\n");

	seq_puts(m, "status: confirmed\n");

or

	seq_puts(m, "status: courtesy\n");


> +	hrs = div_u64_rem(ktime_get_boottime_seconds() - clp->cl_time,
> +				3600, &secs);
> +	mins = div_u64_rem((u64)secs, 60, &secs);
> +	seq_printf(m, "time since last renew: %02ld:%02d:%02d\n", hrs, mins, secs);

Thanks, this seems more friendly than what was here before.

However if we replace the fixed courtesy timeout with a
shrinker, I bet some courtesy clients might lie about for
many more that 99 hours. Perhaps the left-most format
specifier could be just "%lu" and the rest could be "%02u".

(ie, also turn the "d" into "u" to prevent ever displaying
a negative number of time units).


> 	seq_printf(m, "name: ");
> 	seq_quote_mem(m, clp->cl_name.data, clp->cl_name.len);
> 	seq_printf(m, "\nminor version: %d\n", clp->cl_minorversion);
> -- 
> 2.9.5
> 

--
Chuck Lever

Re: [PATCH RFC v15 11/11] NFSD: Show state of courtesy clients in client info

[dai.ngo]

On 3/9/22 12:14 PM, Chuck Lever III wrote:
>
>> On Mar 4, 2022, at 7:37 PM, Dai Ngo <dai.ngo@oracle.com> wrote:
>>
>> Update client_info_show to show state of courtesy client
>> and time since last renew.
>>
>> Signed-off-by: Dai Ngo <dai.ngo@oracle.com>
>> ---
>> fs/nfsd/nfs4state.c | 9 ++++++++-
>> 1 file changed, 8 insertions(+), 1 deletion(-)
>>
>> diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
>> index bced09014e6b..ed14e0b54537 100644
>> --- a/fs/nfsd/nfs4state.c
>> +++ b/fs/nfsd/nfs4state.c
>> @@ -2439,7 +2439,8 @@ static int client_info_show(struct seq_file *m, void *v)
>> {
>> 	struct inode *inode = m->private;
>> 	struct nfs4_client *clp;
>> -	u64 clid;
>> +	u64 clid, hrs;
>> +	u32 mins, secs;
>>
>> 	clp = get_nfsdfs_clp(inode);
>> 	if (!clp)
>> @@ -2451,6 +2452,12 @@ static int client_info_show(struct seq_file *m, void *v)
>> 		seq_puts(m, "status: confirmed\n");
>> 	else
>> 		seq_puts(m, "status: unconfirmed\n");
>> +	seq_printf(m, "courtesy client: %s\n",
>> +		test_bit(NFSD4_CLIENT_COURTESY, &clp->cl_flags) ? "yes" : "no");
> I'm wondering if it would be more economical to combine this
> output with the status output just before it so we have only
> one of:
>
> 	seq_puts(m, "status: unconfirmed\n");
>
> 	seq_puts(m, "status: confirmed\n");
>
> or
>
> 	seq_puts(m, "status: courtesy\n");

make sense, will fix.

>
>
>> +	hrs = div_u64_rem(ktime_get_boottime_seconds() - clp->cl_time,
>> +				3600, &secs);
>> +	mins = div_u64_rem((u64)secs, 60, &secs);
>> +	seq_printf(m, "time since last renew: %02ld:%02d:%02d\n", hrs, mins, secs);
> Thanks, this seems more friendly than what was here before.
>
> However if we replace the fixed courtesy timeout with a
> shrinker, I bet some courtesy clients might lie about for
> many more that 99 hours. Perhaps the left-most format
> specifier could be just "%lu" and the rest could be "%02u".
>
> (ie, also turn the "d" into "u" to prevent ever displaying
> a negative number of time units).

will fix.

I will wait for your review of the rest of the patches before
I submit v16.

Thanks,
-Dai

>
>
>> 	seq_printf(m, "name: ");
>> 	seq_quote_mem(m, clp->cl_name.data, clp->cl_name.len);
>> 	seq_printf(m, "\nminor version: %d\n", clp->cl_minorversion);
>> -- 
>> 2.9.5
>>
> --
> Chuck Lever
>
>
>

Re: [PATCH RFC v15 01/11] fs/lock: add helper locks_any_blockers to check for blockers

[Chuck Lever III]

> On Mar 4, 2022, at 7:37 PM, Dai Ngo <dai.ngo@oracle.com> wrote:
> 
> Add helper locks_any_blockers to check if there is any blockers
> for a file_lock.
> 
> Signed-off-by: Dai Ngo <dai.ngo@oracle.com>
> ---
> include/linux/fs.h | 10 ++++++++++
> 1 file changed, 10 insertions(+)
> 
> diff --git a/include/linux/fs.h b/include/linux/fs.h
> index 831b20430d6e..7f5756bfcc13 100644
> --- a/include/linux/fs.h
> +++ b/include/linux/fs.h
> @@ -1200,6 +1200,11 @@ extern void lease_unregister_notifier(struct notifier_block *);
> struct files_struct;
> extern void show_fd_locks(struct seq_file *f,
> 			 struct file *filp, struct files_struct *files);
> +
> +static inline bool locks_has_blockers_locked(struct file_lock *lck)
> +{
> +	return !list_empty(&lck->fl_blocked_requests);
> +}
> #else /* !CONFIG_FILE_LOCKING */
> static inline int fcntl_getlk(struct file *file, unsigned int cmd,
> 			      struct flock __user *user)
> @@ -1335,6 +1340,11 @@ static inline int lease_modify(struct file_lock *fl, int arg,
> struct files_struct;
> static inline void show_fd_locks(struct seq_file *f,
> 			struct file *filp, struct files_struct *files) {}
> +
> +static inline bool locks_has_blockers_locked(struct file_lock *lck)
> +{
> +	return false;
> +}
> #endif /* !CONFIG_FILE_LOCKING */
> 
> static inline struct inode *file_inode(const struct file *f)

Hm. This is not exactly what I had in mind.

In order to be more kABI friendly, fl_blocked_requests should be 
dereferenced only in fs/locks.c. IMO you want to take the inner
loop in nfs4_lockowner_has_blockers() and make that a function
that lives in fs/locks.c. Something akin to:

fs/locks.c:

/**
 * locks_owner_has_blockers - Check for blocking lock requests
 * @flctx: file lock context
 * @owner: lock owner
 *
 * Return values:
 *   %true: @ctx has at least one blocker
 *   %false: @ctx has no blockers
 */
bool locks_owner_has_blockers(struct file_lock_context *flctx,
			      fl_owner_t owner)
{
	struct file_lock *fl;

	spin_lock(&flctx->flc_lock);
	list_for_each_entry(fl, &flctx->flc_posix, fl_list) {
		if (fl->fl_owner != owner)
			continue;
		if (!list_empty(&fl->fl_blocked_requests)) {
			spin_unlock(&flctx->flc_lock);
			return true;
		}
	}
	spin_unlock(&flctx->flc_lock);
	return false;
}
EXPORT_SYMBOL(locks_owner_has_blockers);

As a subsequent clean up (which anyone can do at a later point),
a similar change could be done to check_for_locks(). This bit of
code seems to appear in several other filesystems, for example:

7643         inode = locks_inode(nf->nf_file);
7644         flctx = inode->i_flctx;
7645 
7646         if (flctx && !list_empty_careful(&flctx->flc_posix)) {
7647                 spin_lock(&flctx->flc_lock);
7648                 list_for_each_entry(fl, &flctx->flc_posix, fl_list) {
7649                         if (fl->fl_owner == (fl_owner_t)lowner) {
7650                                 status = true;
7651                                 break;
7652                         }
7653                 }
7654                 spin_unlock(&flctx->flc_lock);
7655         }


--
Chuck Lever

Re: [PATCH RFC v15 04/11] NFSD: Update nfsd_breaker_owns_lease() to handle courtesy clients

[Chuck Lever III]

> On Mar 4, 2022, at 7:37 PM, Dai Ngo <dai.ngo@oracle.com> wrote:
> 
> Update nfsd_breaker_owns_lease() to handle delegation conflict
> with courtesy clients. If conflict was caused courtesy client
> then discard the courtesy client by setting CLIENT_EXPIRED and
> return conflict resolved. Client with CLIENT_EXPIRED is expired
> by the laundromat.
> 
> Signed-off-by: Dai Ngo <dai.ngo@oracle.com>
> ---
> fs/nfsd/nfs4state.c | 18 ++++++++++++++++++
> 1 file changed, 18 insertions(+)
> 
> diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
> index 583ac807e98d..40a357fd1a14 100644
> --- a/fs/nfsd/nfs4state.c
> +++ b/fs/nfsd/nfs4state.c
> @@ -4727,6 +4727,24 @@ static bool nfsd_breaker_owns_lease(struct file_lock *fl)
> 	struct svc_rqst *rqst;
> 	struct nfs4_client *clp;
> 
> +	clp = dl->dl_stid.sc_client;
> +	/*
> +	 * need to sync with courtesy client trying to reconnect using
> +	 * the cl_cs_lock, nn->client_lock can not be used since this
> +	 * function is called with the fl_lck held.
> +	 */
> +	spin_lock(&clp->cl_cs_lock);
> +	if (test_bit(NFSD4_CLIENT_EXPIRED, &clp->cl_flags)) {
> +		spin_unlock(&clp->cl_cs_lock);
> +		return true;
> +	}
> +	if (test_bit(NFSD4_CLIENT_COURTESY, &clp->cl_flags)) {
> +		set_bit(NFSD4_CLIENT_EXPIRED, &clp->cl_flags);
> +		spin_unlock(&clp->cl_cs_lock);
> +		return true;
> +	}
> +	spin_unlock(&clp->cl_cs_lock);
> +

Nit: Please add nfs4_check_and_expire_courtesy_client() in this patch
instead of in 05/11.


> 	if (!i_am_nfsd())
> 		return false;
> 	rqst = kthread_data(current);
> -- 
> 2.9.5
> 

--
Chuck Lever

Re: [PATCH RFC v15 06/11] NFSD: Update find_clp_in_name_tree() to handle courtesy clients

[Chuck Lever III]

> On Mar 4, 2022, at 7:37 PM, Dai Ngo <dai.ngo@oracle.com> wrote:
> 
> Update find_clp_in_name_tree:
> . skip client with CLIENT_EXPIRED flag; discarded courtesy client.
> . if courtesy client was found then clear CLIENT_COURTESY and
>   set CLIENT_RECONNECTED so callers can take appropriate action.
> 
> Update find_confirmed_client_by_name to discard the courtesy
> client; set CLIENT_EXPIRED.
> 
> Update nfsd4_setclientid to expire the confirmed courtesy client
> to prevent multiple confirmed clients with the same name on the
> the conf_id_hashtbl list.
> 
> Signed-off-by: Dai Ngo <dai.ngo@oracle.com>
> ---
> fs/nfsd/nfs4state.c | 55 ++++++++++++++++++++++++++++++++++++++++++++++++++---
> 1 file changed, 52 insertions(+), 3 deletions(-)
> 
> diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
> index b16f689f34c3..f42d72a8f5ca 100644
> --- a/fs/nfsd/nfs4state.c
> +++ b/fs/nfsd/nfs4state.c
> @@ -1929,6 +1929,34 @@ __find_in_sessionid_hashtbl(struct nfs4_sessionid *sessionid, struct net *net)
> 	return NULL;
> }
> 
> +static void
> +nfsd4_discard_courtesy_clnt(struct nfs4_client *clp)
> +{
> +	spin_lock(&clp->cl_cs_lock);
> +	set_bit(NFSD4_CLIENT_EXPIRED, &clp->cl_flags);
> +	spin_unlock(&clp->cl_cs_lock);
> +}
> +
> +static bool
> +nfs4_is_courtesy_client_expired(struct nfs4_client *clp)
> +{
> +	clear_bit(NFSD4_CLIENT_RECONNECTED, &clp->cl_flags);
> +	/* need to sync with thread resolving lock/deleg conflict */
> +	spin_lock(&clp->cl_cs_lock);
> +	if (test_bit(NFSD4_CLIENT_EXPIRED, &clp->cl_flags)) {
> +		spin_unlock(&clp->cl_cs_lock);
> +		return true;
> +	}
> +	/*
> +	 * clear CLIENT_COURTESY flag to prevent it from being
> +	 * destroyed by thread trying to resolve conflicts.
> +	 */
> +	if (test_and_clear_bit(NFSD4_CLIENT_COURTESY, &clp->cl_flags))
> +		set_bit(NFSD4_CLIENT_RECONNECTED, &clp->cl_flags);
> +	spin_unlock(&clp->cl_cs_lock);
> +	return false;
> +}
> +
> static struct nfsd4_session *
> find_in_sessionid_hashtbl(struct nfs4_sessionid *sessionid, struct net *net,
> 		__be32 *ret)
> @@ -2834,8 +2862,11 @@ find_clp_in_name_tree(struct xdr_netobj *name, struct rb_root *root)
> 			node = node->rb_left;
> 		else if (cmp < 0)
> 			node = node->rb_right;
> -		else
> +		else {
> +			if (nfs4_is_courtesy_client_expired(clp))
> +				return NULL;
> 			return clp;
> +		}
> 	}
> 	return NULL;
> }
> @@ -2914,8 +2945,15 @@ static bool clp_used_exchangeid(struct nfs4_client *clp)
> static struct nfs4_client *
> find_confirmed_client_by_name(struct xdr_netobj *name, struct nfsd_net *nn)
> {
> +	struct nfs4_client *clp;
> +
> 	lockdep_assert_held(&nn->client_lock);
> -	return find_clp_in_name_tree(name, &nn->conf_name_tree);
> +	clp = find_clp_in_name_tree(name, &nn->conf_name_tree);
> +	if (clp && test_bit(NFSD4_CLIENT_RECONNECTED, &clp->cl_flags)) {
> +		nfsd4_discard_courtesy_clnt(clp);
> +		clp = NULL;
> +	}
> +	return clp;
> }

2983 static struct nfs4_client *
2984 find_unconfirmed_client_by_name(struct xdr_netobj *name, struct nfsd_net *nn)
2985 {
2986         lockdep_assert_held(&nn->client_lock);
2987         return find_clp_in_name_tree(name, &nn->unconf_name_tree);
2988 }

Notice the difference:

find_confirmed() does find_clp_in_name_tree(&nn->conf_name_tree);
                                                 ^^^^

find_unconfirmed() does find_clp_in_name_tree(&nn->unconf_name_tree);
                                                   ^^^^^^

I don't think we will ever find a client in unconf_name_tree that
has CLIENT_RECONNECTED set, will we? So it seems to me that you
can safely move the CLIENT_RECONNECTED test into
find_clp_in_name_tree() in all cases, maybe?

Or think about it this way: is it possible for an unconfirmed
client to become a courtesy client? I don't think it is.


> @@ -4032,12 +4070,19 @@ nfsd4_setclientid(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
> 	struct nfs4_client	*unconf = NULL;
> 	__be32 			status;
> 	struct nfsd_net		*nn = net_generic(SVC_NET(rqstp), nfsd_net_id);
> +	struct nfs4_client	*cclient = NULL;
> 
> 	new = create_client(clname, rqstp, &clverifier);
> 	if (new == NULL)
> 		return nfserr_jukebox;
> 	spin_lock(&nn->client_lock);
> -	conf = find_confirmed_client_by_name(&clname, nn);
> +	/* find confirmed client by name */
> +	conf = find_clp_in_name_tree(&clname, &nn->conf_name_tree);
> +	if (conf && test_bit(NFSD4_CLIENT_RECONNECTED, &conf->cl_flags)) {
> +		cclient = conf;
> +		conf = NULL;
> +	}
> +
> 	if (conf && client_has_state(conf)) {
> 		status = nfserr_clid_inuse;
> 		if (clp_used_exchangeid(conf))
> @@ -4068,7 +4113,11 @@ nfsd4_setclientid(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
> 	new = NULL;
> 	status = nfs_ok;
> out:
> +	if (cclient)
> +		unhash_client_locked(cclient);
> 	spin_unlock(&nn->client_lock);
> +	if (cclient)
> +		expire_client(cclient);
> 	if (new)
> 		free_client(new);
> 	if (unconf) {
> -- 
> 2.9.5
> 

--
Chuck Lever

Re: [PATCH RFC v15 07/11] NFSD: Update find_in_sessionid_hashtbl() to handle courtesy clients

[Chuck Lever III]

> On Mar 4, 2022, at 7:37 PM, Dai Ngo <dai.ngo@oracle.com> wrote:
> 
> Update find_in_sessionid_hashtbl to:
> . skip client with CLIENT_EXPIRED flag; discarded courtesy client.
> . if courtesy client was found then clear CLIENT_COURTESY and
>   set CLIENT_RECONNECTED so callers can take appropriate action.
> 
> Update nfsd4_sequence and nfsd4_bind_conn_to_session to create client
> record for client with CLIENT_RECONNECTED set.
> 
> Update nfsd4_destroy_session to discard client with CLIENT_RECONNECTED
> set.
> 
> Signed-off-by: Dai Ngo <dai.ngo@oracle.com>
> ---
> fs/nfsd/nfs4state.c | 34 ++++++++++++++++++++++++++++++++--
> 1 file changed, 32 insertions(+), 2 deletions(-)
> 
> diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
> index f42d72a8f5ca..34a59c6f446c 100644
> --- a/fs/nfsd/nfs4state.c
> +++ b/fs/nfsd/nfs4state.c
> @@ -1963,13 +1963,22 @@ find_in_sessionid_hashtbl(struct nfs4_sessionid *sessionid, struct net *net,
> {
> 	struct nfsd4_session *session;
> 	__be32 status = nfserr_badsession;
> +	struct nfs4_client *clp;
> 
> 	session = __find_in_sessionid_hashtbl(sessionid, net);
> 	if (!session)
> 		goto out;
> +	clp = session->se_client;
> +	if (clp && nfs4_is_courtesy_client_expired(clp)) {
> +		session = NULL;
> +		goto out;
> +	}
> 	status = nfsd4_get_session_locked(session);
> -	if (status)
> +	if (status) {
> 		session = NULL;
> +		if (clp && test_bit(NFSD4_CLIENT_COURTESY, &clp->cl_flags))
> +			nfsd4_discard_courtesy_clnt(clp);
> +	}

Here and above: I'm not seeing how @clp can be NULL, but I'm kind
of new to fs/nfsd/nfs4state.c.


--
Chuck Lever

Re: [PATCH RFC v15 11/11] NFSD: Show state of courtesy clients in client info

[dai.ngo]

On 3/9/22 12:51 PM, dai.ngo@oracle.com wrote:
>
> On 3/9/22 12:14 PM, Chuck Lever III wrote:
>>
>>> On Mar 4, 2022, at 7:37 PM, Dai Ngo <dai.ngo@oracle.com> wrote:
>>>
>>> Update client_info_show to show state of courtesy client
>>> and time since last renew.
>>>
>>> Signed-off-by: Dai Ngo <dai.ngo@oracle.com>
>>> ---
>>> fs/nfsd/nfs4state.c | 9 ++++++++-
>>> 1 file changed, 8 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
>>> index bced09014e6b..ed14e0b54537 100644
>>> --- a/fs/nfsd/nfs4state.c
>>> +++ b/fs/nfsd/nfs4state.c
>>> @@ -2439,7 +2439,8 @@ static int client_info_show(struct seq_file 
>>> *m, void *v)
>>> {
>>>     struct inode *inode = m->private;
>>>     struct nfs4_client *clp;
>>> -    u64 clid;
>>> +    u64 clid, hrs;
>>> +    u32 mins, secs;
>>>
>>>     clp = get_nfsdfs_clp(inode);
>>>     if (!clp)
>>> @@ -2451,6 +2452,12 @@ static int client_info_show(struct seq_file 
>>> *m, void *v)
>>>         seq_puts(m, "status: confirmed\n");
>>>     else
>>>         seq_puts(m, "status: unconfirmed\n");
>>> +    seq_printf(m, "courtesy client: %s\n",
>>> +        test_bit(NFSD4_CLIENT_COURTESY, &clp->cl_flags) ? "yes" : 
>>> "no");
>> I'm wondering if it would be more economical to combine this
>> output with the status output just before it so we have only
>> one of:
>>
>>     seq_puts(m, "status: unconfirmed\n");
>>
>>     seq_puts(m, "status: confirmed\n");
>>
>> or
>>
>>     seq_puts(m, "status: courtesy\n");
>
> make sense, will fix.

On second thought, I think it's safer to keep this the same
since there might be scripts out there that depend on it.

-Dai

>
>>
>>
>>> +    hrs = div_u64_rem(ktime_get_boottime_seconds() - clp->cl_time,
>>> +                3600, &secs);
>>> +    mins = div_u64_rem((u64)secs, 60, &secs);
>>> +    seq_printf(m, "time since last renew: %02ld:%02d:%02d\n", hrs, 
>>> mins, secs);
>> Thanks, this seems more friendly than what was here before.
>>
>> However if we replace the fixed courtesy timeout with a
>> shrinker, I bet some courtesy clients might lie about for
>> many more that 99 hours. Perhaps the left-most format
>> specifier could be just "%lu" and the rest could be "%02u".
>>
>> (ie, also turn the "d" into "u" to prevent ever displaying
>> a negative number of time units).
>
> will fix.
>
> I will wait for your review of the rest of the patches before
> I submit v16.
>
> Thanks,
> -Dai
>
>>
>>
>>>     seq_printf(m, "name: ");
>>>     seq_quote_mem(m, clp->cl_name.data, clp->cl_name.len);
>>>     seq_printf(m, "\nminor version: %d\n", clp->cl_minorversion);
>>> -- 
>>> 2.9.5
>>>
>> -- 
>> Chuck Lever
>>
>>
>>

Re: [PATCH RFC v15 01/11] fs/lock: add helper locks_any_blockers to check for blockers

[dai.ngo]

On 3/9/22 12:56 PM, Chuck Lever III wrote:
>
>> On Mar 4, 2022, at 7:37 PM, Dai Ngo <dai.ngo@oracle.com> wrote:
>>
>> Add helper locks_any_blockers to check if there is any blockers
>> for a file_lock.
>>
>> Signed-off-by: Dai Ngo <dai.ngo@oracle.com>
>> ---
>> include/linux/fs.h | 10 ++++++++++
>> 1 file changed, 10 insertions(+)
>>
>> diff --git a/include/linux/fs.h b/include/linux/fs.h
>> index 831b20430d6e..7f5756bfcc13 100644
>> --- a/include/linux/fs.h
>> +++ b/include/linux/fs.h
>> @@ -1200,6 +1200,11 @@ extern void lease_unregister_notifier(struct notifier_block *);
>> struct files_struct;
>> extern void show_fd_locks(struct seq_file *f,
>> 			 struct file *filp, struct files_struct *files);
>> +
>> +static inline bool locks_has_blockers_locked(struct file_lock *lck)
>> +{
>> +	return !list_empty(&lck->fl_blocked_requests);
>> +}
>> #else /* !CONFIG_FILE_LOCKING */
>> static inline int fcntl_getlk(struct file *file, unsigned int cmd,
>> 			      struct flock __user *user)
>> @@ -1335,6 +1340,11 @@ static inline int lease_modify(struct file_lock *fl, int arg,
>> struct files_struct;
>> static inline void show_fd_locks(struct seq_file *f,
>> 			struct file *filp, struct files_struct *files) {}
>> +
>> +static inline bool locks_has_blockers_locked(struct file_lock *lck)
>> +{
>> +	return false;
>> +}
>> #endif /* !CONFIG_FILE_LOCKING */
>>
>> static inline struct inode *file_inode(const struct file *f)
> Hm. This is not exactly what I had in mind.
>
> In order to be more kABI friendly, fl_blocked_requests should be
> dereferenced only in fs/locks.c. IMO you want to take the inner
> loop in nfs4_lockowner_has_blockers() and make that a function
> that lives in fs/locks.c. Something akin to:
>
> fs/locks.c:
>
> /**
>   * locks_owner_has_blockers - Check for blocking lock requests
>   * @flctx: file lock context
>   * @owner: lock owner
>   *
>   * Return values:
>   *   %true: @ctx has at least one blocker
>   *   %false: @ctx has no blockers
>   */
> bool locks_owner_has_blockers(struct file_lock_context *flctx,
> 			      fl_owner_t owner)
> {
> 	struct file_lock *fl;
>
> 	spin_lock(&flctx->flc_lock);
> 	list_for_each_entry(fl, &flctx->flc_posix, fl_list) {
> 		if (fl->fl_owner != owner)
> 			continue;
> 		if (!list_empty(&fl->fl_blocked_requests)) {
> 			spin_unlock(&flctx->flc_lock);
> 			return true;
> 		}
> 	}
> 	spin_unlock(&flctx->flc_lock);
> 	return false;
> }
> EXPORT_SYMBOL(locks_owner_has_blockers);
>
> As a subsequent clean up (which anyone can do at a later point),
> a similar change could be done to check_for_locks(). This bit of
> code seems to appear in several other filesystems, for example:

I used check_for_locks as reference for locks_owner_has_blockers
so both should be updated to be more kABI friendly as you suggested.
Can I update both in a subsequent cleanup patch? I plan to have
a number of small cleanup up patches for these and also some nits.

Thanks,
-Dai


>
> 7643         inode = locks_inode(nf->nf_file);
> 7644         flctx = inode->i_flctx;
> 7645
> 7646         if (flctx && !list_empty_careful(&flctx->flc_posix)) {
> 7647                 spin_lock(&flctx->flc_lock);
> 7648                 list_for_each_entry(fl, &flctx->flc_posix, fl_list) {
> 7649                         if (fl->fl_owner == (fl_owner_t)lowner) {
> 7650                                 status = true;
> 7651                                 break;
> 7652                         }
> 7653                 }
> 7654                 spin_unlock(&flctx->flc_lock);
> 7655         }
>
>
> --
> Chuck Lever
>
>
>

Re: [PATCH RFC v15 06/11] NFSD: Update find_clp_in_name_tree() to handle courtesy clients

[dai.ngo]

On 3/9/22 2:08 PM, Chuck Lever III wrote:
>
>> On Mar 4, 2022, at 7:37 PM, Dai Ngo <dai.ngo@oracle.com> wrote:
>>
>> Update find_clp_in_name_tree:
>> . skip client with CLIENT_EXPIRED flag; discarded courtesy client.
>> . if courtesy client was found then clear CLIENT_COURTESY and
>>    set CLIENT_RECONNECTED so callers can take appropriate action.
>>
>> Update find_confirmed_client_by_name to discard the courtesy
>> client; set CLIENT_EXPIRED.
>>
>> Update nfsd4_setclientid to expire the confirmed courtesy client
>> to prevent multiple confirmed clients with the same name on the
>> the conf_id_hashtbl list.
>>
>> Signed-off-by: Dai Ngo <dai.ngo@oracle.com>
>> ---
>> fs/nfsd/nfs4state.c | 55 ++++++++++++++++++++++++++++++++++++++++++++++++++---
>> 1 file changed, 52 insertions(+), 3 deletions(-)
>>
>> diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
>> index b16f689f34c3..f42d72a8f5ca 100644
>> --- a/fs/nfsd/nfs4state.c
>> +++ b/fs/nfsd/nfs4state.c
>> @@ -1929,6 +1929,34 @@ __find_in_sessionid_hashtbl(struct nfs4_sessionid *sessionid, struct net *net)
>> 	return NULL;
>> }
>>
>> +static void
>> +nfsd4_discard_courtesy_clnt(struct nfs4_client *clp)
>> +{
>> +	spin_lock(&clp->cl_cs_lock);
>> +	set_bit(NFSD4_CLIENT_EXPIRED, &clp->cl_flags);
>> +	spin_unlock(&clp->cl_cs_lock);
>> +}
>> +
>> +static bool
>> +nfs4_is_courtesy_client_expired(struct nfs4_client *clp)
>> +{
>> +	clear_bit(NFSD4_CLIENT_RECONNECTED, &clp->cl_flags);
>> +	/* need to sync with thread resolving lock/deleg conflict */
>> +	spin_lock(&clp->cl_cs_lock);
>> +	if (test_bit(NFSD4_CLIENT_EXPIRED, &clp->cl_flags)) {
>> +		spin_unlock(&clp->cl_cs_lock);
>> +		return true;
>> +	}
>> +	/*
>> +	 * clear CLIENT_COURTESY flag to prevent it from being
>> +	 * destroyed by thread trying to resolve conflicts.
>> +	 */
>> +	if (test_and_clear_bit(NFSD4_CLIENT_COURTESY, &clp->cl_flags))
>> +		set_bit(NFSD4_CLIENT_RECONNECTED, &clp->cl_flags);
>> +	spin_unlock(&clp->cl_cs_lock);
>> +	return false;
>> +}
>> +
>> static struct nfsd4_session *
>> find_in_sessionid_hashtbl(struct nfs4_sessionid *sessionid, struct net *net,
>> 		__be32 *ret)
>> @@ -2834,8 +2862,11 @@ find_clp_in_name_tree(struct xdr_netobj *name, struct rb_root *root)
>> 			node = node->rb_left;
>> 		else if (cmp < 0)
>> 			node = node->rb_right;
>> -		else
>> +		else {
>> +			if (nfs4_is_courtesy_client_expired(clp))
>> +				return NULL;
>> 			return clp;
>> +		}
>> 	}
>> 	return NULL;
>> }
>> @@ -2914,8 +2945,15 @@ static bool clp_used_exchangeid(struct nfs4_client *clp)
>> static struct nfs4_client *
>> find_confirmed_client_by_name(struct xdr_netobj *name, struct nfsd_net *nn)
>> {
>> +	struct nfs4_client *clp;
>> +
>> 	lockdep_assert_held(&nn->client_lock);
>> -	return find_clp_in_name_tree(name, &nn->conf_name_tree);
>> +	clp = find_clp_in_name_tree(name, &nn->conf_name_tree);
>> +	if (clp && test_bit(NFSD4_CLIENT_RECONNECTED, &clp->cl_flags)) {
>> +		nfsd4_discard_courtesy_clnt(clp);
>> +		clp = NULL;
>> +	}
>> +	return clp;
>> }
> 2983 static struct nfs4_client *
> 2984 find_unconfirmed_client_by_name(struct xdr_netobj *name, struct nfsd_net *nn)
> 2985 {
> 2986         lockdep_assert_held(&nn->client_lock);
> 2987         return find_clp_in_name_tree(name, &nn->unconf_name_tree);
> 2988 }
>
> Notice the difference:
>
> find_confirmed() does find_clp_in_name_tree(&nn->conf_name_tree);
>                                                   ^^^^
>
> find_unconfirmed() does find_clp_in_name_tree(&nn->unconf_name_tree);
>                                                     ^^^^^^
>
> I don't think we will ever find a client in unconf_name_tree that
> has CLIENT_RECONNECTED set, will we?

No.

> So it seems to me that you
> can safely move the CLIENT_RECONNECTED test into
> find_clp_in_name_tree() in all cases, maybe?

nfsd4_setclientid needs to treat the courtesy client a little
differently from find_[un]confirmed_client_by_name. It has to
expire the courtesy client immediately to prevent multiple
confirmed clients with the same name on the the conf_id_hashtbl
list which causes problem for the subsequent setclientid_confirm.

-Dai

>
> Or think about it this way: is it possible for an unconfirmed
> client to become a courtesy client? I don't think it is.
>
>
>> @@ -4032,12 +4070,19 @@ nfsd4_setclientid(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
>> 	struct nfs4_client	*unconf = NULL;
>> 	__be32 			status;
>> 	struct nfsd_net		*nn = net_generic(SVC_NET(rqstp), nfsd_net_id);
>> +	struct nfs4_client	*cclient = NULL;
>>
>> 	new = create_client(clname, rqstp, &clverifier);
>> 	if (new == NULL)
>> 		return nfserr_jukebox;
>> 	spin_lock(&nn->client_lock);
>> -	conf = find_confirmed_client_by_name(&clname, nn);
>> +	/* find confirmed client by name */
>> +	conf = find_clp_in_name_tree(&clname, &nn->conf_name_tree);
>> +	if (conf && test_bit(NFSD4_CLIENT_RECONNECTED, &conf->cl_flags)) {
>> +		cclient = conf;
>> +		conf = NULL;
>> +	}
>> +
>> 	if (conf && client_has_state(conf)) {
>> 		status = nfserr_clid_inuse;
>> 		if (clp_used_exchangeid(conf))
>> @@ -4068,7 +4113,11 @@ nfsd4_setclientid(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
>> 	new = NULL;
>> 	status = nfs_ok;
>> out:
>> +	if (cclient)
>> +		unhash_client_locked(cclient);
>> 	spin_unlock(&nn->client_lock);
>> +	if (cclient)
>> +		expire_client(cclient);
>> 	if (new)
>> 		free_client(new);
>> 	if (unconf) {
>> -- 
>> 2.9.5
>>
> --
> Chuck Lever
>
>
>

Re: [PATCH RFC v15 07/11] NFSD: Update find_in_sessionid_hashtbl() to handle courtesy clients

[dai.ngo]

On 3/9/22 2:42 PM, Chuck Lever III wrote:
>
>> On Mar 4, 2022, at 7:37 PM, Dai Ngo <dai.ngo@oracle.com> wrote:
>>
>> Update find_in_sessionid_hashtbl to:
>> . skip client with CLIENT_EXPIRED flag; discarded courtesy client.
>> . if courtesy client was found then clear CLIENT_COURTESY and
>>    set CLIENT_RECONNECTED so callers can take appropriate action.
>>
>> Update nfsd4_sequence and nfsd4_bind_conn_to_session to create client
>> record for client with CLIENT_RECONNECTED set.
>>
>> Update nfsd4_destroy_session to discard client with CLIENT_RECONNECTED
>> set.
>>
>> Signed-off-by: Dai Ngo <dai.ngo@oracle.com>
>> ---
>> fs/nfsd/nfs4state.c | 34 ++++++++++++++++++++++++++++++++--
>> 1 file changed, 32 insertions(+), 2 deletions(-)
>>
>> diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
>> index f42d72a8f5ca..34a59c6f446c 100644
>> --- a/fs/nfsd/nfs4state.c
>> +++ b/fs/nfsd/nfs4state.c
>> @@ -1963,13 +1963,22 @@ find_in_sessionid_hashtbl(struct nfs4_sessionid *sessionid, struct net *net,
>> {
>> 	struct nfsd4_session *session;
>> 	__be32 status = nfserr_badsession;
>> +	struct nfs4_client *clp;
>>
>> 	session = __find_in_sessionid_hashtbl(sessionid, net);
>> 	if (!session)
>> 		goto out;
>> +	clp = session->se_client;
>> +	if (clp && nfs4_is_courtesy_client_expired(clp)) {
>> +		session = NULL;
>> +		goto out;
>> +	}
>> 	status = nfsd4_get_session_locked(session);
>> -	if (status)
>> +	if (status) {
>> 		session = NULL;
>> +		if (clp && test_bit(NFSD4_CLIENT_COURTESY, &clp->cl_flags))
>> +			nfsd4_discard_courtesy_clnt(clp);
>> +	}
> Here and above: I'm not seeing how @clp can be NULL, but I'm kind
> of new to fs/nfsd/nfs4state.c.

it seems like @clp can not be NULL since existing code does not
check for it. I will remove it to avoid any confusion. Can this
be done a a separate clean up patch?

Thanks,
-Dai

>
>
> --
> Chuck Lever
>
>
>

Re: [PATCH RFC v15 11/11] NFSD: Show state of courtesy clients in client info

[Chuck Lever III]

> On Mar 9, 2022, at 10:09 PM, Dai Ngo <dai.ngo@oracle.com> wrote:
> 
> 
>> On 3/9/22 12:51 PM, dai.ngo@oracle.com wrote:
>> 
>>> On 3/9/22 12:14 PM, Chuck Lever III wrote:
>>> 
>>>> On Mar 4, 2022, at 7:37 PM, Dai Ngo <dai.ngo@oracle.com> wrote:
>>>> 
>>>> Update client_info_show to show state of courtesy client
>>>> and time since last renew.
>>>> 
>>>> Signed-off-by: Dai Ngo <dai.ngo@oracle.com>
>>>> ---
>>>> fs/nfsd/nfs4state.c | 9 ++++++++-
>>>> 1 file changed, 8 insertions(+), 1 deletion(-)
>>>> 
>>>> diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
>>>> index bced09014e6b..ed14e0b54537 100644
>>>> --- a/fs/nfsd/nfs4state.c
>>>> +++ b/fs/nfsd/nfs4state.c
>>>> @@ -2439,7 +2439,8 @@ static int client_info_show(struct seq_file *m, void *v)
>>>> {
>>>>     struct inode *inode = m->private;
>>>>     struct nfs4_client *clp;
>>>> -    u64 clid;
>>>> +    u64 clid, hrs;
>>>> +    u32 mins, secs;
>>>> 
>>>>     clp = get_nfsdfs_clp(inode);
>>>>     if (!clp)
>>>> @@ -2451,6 +2452,12 @@ static int client_info_show(struct seq_file *m, void *v)
>>>>         seq_puts(m, "status: confirmed\n");
>>>>     else
>>>>         seq_puts(m, "status: unconfirmed\n");
>>>> +    seq_printf(m, "courtesy client: %s\n",
>>>> +        test_bit(NFSD4_CLIENT_COURTESY, &clp->cl_flags) ? "yes" : "no");
>>> I'm wondering if it would be more economical to combine this
>>> output with the status output just before it so we have only
>>> one of:
>>> 
>>>     seq_puts(m, "status: unconfirmed\n");
>>> 
>>>     seq_puts(m, "status: confirmed\n");
>>> 
>>> or
>>> 
>>>     seq_puts(m, "status: courtesy\n");
>> 
>> make sense, will fix.
> 
> On second thought, I think it's safer to keep this the same
> since there might be scripts out there that depend on it.

I agree we should be sensitive to potential users of this information. However…

Without having one or two examples of such scripts in front of us, it’s hard to say whether my suggestion (a new keyword after “status:”) or your original (a new line in the file) would be more disruptive.

Also I’m not seeing exactly how the output format is versioned… so what’s the safest way to make changes to the output format of this file? Anyone?

When I get in front of a computer again, I’ll have a look at the change history of this function.


> -Dai
> 
>> 
>>> 
>>> 
>>>> +    hrs = div_u64_rem(ktime_get_boottime_seconds() - clp->cl_time,
>>>> +                3600, &secs);
>>>> +    mins = div_u64_rem((u64)secs, 60, &secs);
>>>> +    seq_printf(m, "time since last renew: %02ld:%02d:%02d\n", hrs, mins, secs);
>>> Thanks, this seems more friendly than what was here before.
>>> 
>>> However if we replace the fixed courtesy timeout with a
>>> shrinker, I bet some courtesy clients might lie about for
>>> many more that 99 hours. Perhaps the left-most format
>>> specifier could be just "%lu" and the rest could be "%02u".
>>> 
>>> (ie, also turn the "d" into "u" to prevent ever displaying
>>> a negative number of time units).
>> 
>> will fix.
>> 
>> I will wait for your review of the rest of the patches before
>> I submit v16.
>> 
>> Thanks,
>> -Dai
>> 
>>> 
>>> 
>>>>     seq_printf(m, "name: ");
>>>>     seq_quote_mem(m, clp->cl_name.data, clp->cl_name.len);
>>>>     seq_printf(m, "\nminor version: %d\n", clp->cl_minorversion);
>>>> -- 
>>>> 2.9.5
>>>> 
>>> -- 
>>> Chuck Lever
>>> 
>>> 
>>> 

Re: [PATCH RFC v15 07/11] NFSD: Update find_in_sessionid_hashtbl() to handle courtesy clients

[Chuck Lever III]

> On Mar 9, 2022, at 10:12 PM, Dai Ngo <dai.ngo@oracle.com> wrote:
> 
> 
>> On 3/9/22 2:42 PM, Chuck Lever III wrote:
>> 
>>>> On Mar 4, 2022, at 7:37 PM, Dai Ngo <dai.ngo@oracle.com> wrote:
>>> 
>>> Update find_in_sessionid_hashtbl to:
>>> . skip client with CLIENT_EXPIRED flag; discarded courtesy client.
>>> . if courtesy client was found then clear CLIENT_COURTESY and
>>>   set CLIENT_RECONNECTED so callers can take appropriate action.
>>> 
>>> Update nfsd4_sequence and nfsd4_bind_conn_to_session to create client
>>> record for client with CLIENT_RECONNECTED set.
>>> 
>>> Update nfsd4_destroy_session to discard client with CLIENT_RECONNECTED
>>> set.
>>> 
>>> Signed-off-by: Dai Ngo <dai.ngo@oracle.com>
>>> ---
>>> fs/nfsd/nfs4state.c | 34 ++++++++++++++++++++++++++++++++--
>>> 1 file changed, 32 insertions(+), 2 deletions(-)
>>> 
>>> diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
>>> index f42d72a8f5ca..34a59c6f446c 100644
>>> --- a/fs/nfsd/nfs4state.c
>>> +++ b/fs/nfsd/nfs4state.c
>>> @@ -1963,13 +1963,22 @@ find_in_sessionid_hashtbl(struct nfs4_sessionid *sessionid, struct net *net,
>>> {
>>>    struct nfsd4_session *session;
>>>    __be32 status = nfserr_badsession;
>>> +    struct nfs4_client *clp;
>>> 
>>>    session = __find_in_sessionid_hashtbl(sessionid, net);
>>>    if (!session)
>>>        goto out;
>>> +    clp = session->se_client;
>>> +    if (clp && nfs4_is_courtesy_client_expired(clp)) {
>>> +        session = NULL;
>>> +        goto out;
>>> +    }
>>>    status = nfsd4_get_session_locked(session);
>>> -    if (status)
>>> +    if (status) {
>>>        session = NULL;
>>> +        if (clp && test_bit(NFSD4_CLIENT_COURTESY, &clp->cl_flags))

By the way, I don’t understand why this checks CLIENT_COURTESY to see if the clp should be discarded. Shouldn’t it check CLIENT_RECONNECTED like the other sites?


>>> +            nfsd4_discard_courtesy_clnt(clp);
>>> +    }
>> Here and above: I'm not seeing how @clp can be NULL, but I'm kind
>> of new to fs/nfsd/nfs4state.c.
> 
> it seems like @clp can not be NULL since existing code does not
> check for it. I will remove it to avoid any confusion. Can this
> be done as a separate clean up patch?

I don’t think this series is going to make v5.18. We can keep working on improving each of the patches. And I would rather ensure that the series is properly bisectable. I don’t think we’re at a point where the patches are immutable.


> Thanks,
> -Dai
> 
>> 
>> 
>> --
>> Chuck Lever
>> 
>> 
>> 

Re: [PATCH RFC v15 01/11] fs/lock: add helper locks_any_blockers to check for blockers

[Chuck Lever III]

> On Mar 9, 2022, at 10:11 PM, Dai Ngo <dai.ngo@oracle.com> wrote:
> 
> On 3/9/22 12:56 PM, Chuck Lever III wrote:
>> 
>>>> On Mar 4, 2022, at 7:37 PM, Dai Ngo <dai.ngo@oracle.com> wrote:
>>> 
>>> Add helper locks_any_blockers to check if there is any blockers
>>> for a file_lock.
>>> 
>>> Signed-off-by: Dai Ngo <dai.ngo@oracle.com>
>>> ---
>>> include/linux/fs.h | 10 ++++++++++
>>> 1 file changed, 10 insertions(+)
>>> 
>>> diff --git a/include/linux/fs.h b/include/linux/fs.h
>>> index 831b20430d6e..7f5756bfcc13 100644
>>> --- a/include/linux/fs.h
>>> +++ b/include/linux/fs.h
>>> @@ -1200,6 +1200,11 @@ extern void lease_unregister_notifier(struct notifier_block *);
>>> struct files_struct;
>>> extern void show_fd_locks(struct seq_file *f,
>>>             struct file *filp, struct files_struct *files);
>>> +
>>> +static inline bool locks_has_blockers_locked(struct file_lock *lck)
>>> +{
>>> +    return !list_empty(&lck->fl_blocked_requests);
>>> +}
>>> #else /* !CONFIG_FILE_LOCKING */
>>> static inline int fcntl_getlk(struct file *file, unsigned int cmd,
>>>                  struct flock __user *user)
>>> @@ -1335,6 +1340,11 @@ static inline int lease_modify(struct file_lock *fl, int arg,
>>> struct files_struct;
>>> static inline void show_fd_locks(struct seq_file *f,
>>>            struct file *filp, struct files_struct *files) {}
>>> +
>>> +static inline bool locks_has_blockers_locked(struct file_lock *lck)
>>> +{
>>> +    return false;
>>> +}
>>> #endif /* !CONFIG_FILE_LOCKING */
>>> 
>>> static inline struct inode *file_inode(const struct file *f)
>> Hm. This is not exactly what I had in mind.
>> 
>> In order to be more kABI friendly, fl_blocked_requests should be
>> dereferenced only in fs/locks.c. IMO you want to take the inner
>> loop in nfs4_lockowner_has_blockers() and make that a function
>> that lives in fs/locks.c. Something akin to:
>> 
>> fs/locks.c:
>> 
>> /**
>>  * locks_owner_has_blockers - Check for blocking lock requests
>>  * @flctx: file lock context
>>  * @owner: lock owner
>>  *
>>  * Return values:
>>  *   %true: @ctx has at least one blocker
>>  *   %false: @ctx has no blockers
>>  */
>> bool locks_owner_has_blockers(struct file_lock_context *flctx,
>>                  fl_owner_t owner)
>> {
>>    struct file_lock *fl;
>> 
>>    spin_lock(&flctx->flc_lock);
>>    list_for_each_entry(fl, &flctx->flc_posix, fl_list) {
>>        if (fl->fl_owner != owner)
>>            continue;
>>        if (!list_empty(&fl->fl_blocked_requests)) {
>>            spin_unlock(&flctx->flc_lock);
>>            return true;
>>        }
>>    }
>>    spin_unlock(&flctx->flc_lock);
>>    return false;
>> }
>> EXPORT_SYMBOL(locks_owner_has_blockers);
>> 
>> As a subsequent clean up (which anyone can do at a later point),
>> a similar change could be done to check_for_locks(). This bit of
>> code seems to appear in several other filesystems, for example:
> 
> I used check_for_locks as reference for locks_owner_has_blockers
> so both should be updated to be more kABI friendly as you suggested.
> Can I update both in a subsequent cleanup patch?

No. I prefer that you don’t introduce code and then clean it up later in the same series.

You need to introduce locks_owner_has_blockers() in the same patch where you add the nfsd4_ function that will use it. I think that’s like 7 or 8/11 ? I don’t have it in front of me.

Because it deduplicates code, cleaning up check_for_locks() will need to involve at least one other site (outside of NFSD) that can make use of this new helper. Therefore I prefer that you wait and do that work after courteous server is merged.


> I plan to have a number of small cleanup up patches for these and also some nits.

Clean-ups of areas not having to do with courteous server can go in separate patches, but I would prefer to keep clean-ups of the new code in this series integrated together in the same patches with the new code.

Let’s stay focused on finishing the courteous server work and getting it merged.


> Thanks,
> -Dai
> 
> 
>> 
>> 7643         inode = locks_inode(nf->nf_file);
>> 7644         flctx = inode->i_flctx;
>> 7645
>> 7646         if (flctx && !list_empty_careful(&flctx->flc_posix)) {
>> 7647                 spin_lock(&flctx->flc_lock);
>> 7648                 list_for_each_entry(fl, &flctx->flc_posix, fl_list) {
>> 7649                         if (fl->fl_owner == (fl_owner_t)lowner) {
>> 7650                                 status = true;
>> 7651                                 break;
>> 7652                         }
>> 7653                 }
>> 7654                 spin_unlock(&flctx->flc_lock);
>> 7655         }
>> 
>> 
>> --
>> Chuck Lever
>> 
>> 
>> 

Re: [PATCH RFC v15 07/11] NFSD: Update find_in_sessionid_hashtbl() to handle courtesy clients

[dai.ngo]

On 3/9/22 7:33 PM, Chuck Lever III wrote:
>> On Mar 9, 2022, at 10:12 PM, Dai Ngo <dai.ngo@oracle.com> wrote:
>>
>> 
>>> On 3/9/22 2:42 PM, Chuck Lever III wrote:
>>>
>>>>> On Mar 4, 2022, at 7:37 PM, Dai Ngo <dai.ngo@oracle.com> wrote:
>>>> Update find_in_sessionid_hashtbl to:
>>>> . skip client with CLIENT_EXPIRED flag; discarded courtesy client.
>>>> . if courtesy client was found then clear CLIENT_COURTESY and
>>>>    set CLIENT_RECONNECTED so callers can take appropriate action.
>>>>
>>>> Update nfsd4_sequence and nfsd4_bind_conn_to_session to create client
>>>> record for client with CLIENT_RECONNECTED set.
>>>>
>>>> Update nfsd4_destroy_session to discard client with CLIENT_RECONNECTED
>>>> set.
>>>>
>>>> Signed-off-by: Dai Ngo <dai.ngo@oracle.com>
>>>> ---
>>>> fs/nfsd/nfs4state.c | 34 ++++++++++++++++++++++++++++++++--
>>>> 1 file changed, 32 insertions(+), 2 deletions(-)
>>>>
>>>> diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
>>>> index f42d72a8f5ca..34a59c6f446c 100644
>>>> --- a/fs/nfsd/nfs4state.c
>>>> +++ b/fs/nfsd/nfs4state.c
>>>> @@ -1963,13 +1963,22 @@ find_in_sessionid_hashtbl(struct nfs4_sessionid *sessionid, struct net *net,
>>>> {
>>>>     struct nfsd4_session *session;
>>>>     __be32 status = nfserr_badsession;
>>>> +    struct nfs4_client *clp;
>>>>
>>>>     session = __find_in_sessionid_hashtbl(sessionid, net);
>>>>     if (!session)
>>>>         goto out;
>>>> +    clp = session->se_client;
>>>> +    if (clp && nfs4_is_courtesy_client_expired(clp)) {
>>>> +        session = NULL;
>>>> +        goto out;
>>>> +    }
>>>>     status = nfsd4_get_session_locked(session);
>>>> -    if (status)
>>>> +    if (status) {
>>>>         session = NULL;
>>>> +        if (clp && test_bit(NFSD4_CLIENT_COURTESY, &clp->cl_flags))
> By the way, I don’t understand why this checks CLIENT_COURTESY to see if the clp should be discarded. Shouldn’t it check CLIENT_RECONNECTED like the other sites?

Thanks, this should check for CLIENT_RECONNECTED as described
in the commit message.

>
>
>>>> +            nfsd4_discard_courtesy_clnt(clp);
>>>> +    }
>>> Here and above: I'm not seeing how @clp can be NULL, but I'm kind
>>> of new to fs/nfsd/nfs4state.c.
>> it seems like @clp can not be NULL since existing code does not
>> check for it. I will remove it to avoid any confusion. Can this
>> be done as a separate clean up patch?
> I don’t think this series is going to make v5.18. We can keep working on improving each of the patches. And I would rather ensure that the series is properly bisectable. I don’t think we’re at a point where the patches are immutable.

okay, I will submit v16 to address review comments.

-Dai

Re: [PATCH RFC v15 01/11] fs/lock: add helper locks_any_blockers to check for blockers

[dai.ngo]

On 3/9/22 8:08 PM, Chuck Lever III wrote:
>> On Mar 9, 2022, at 10:11 PM, Dai Ngo <dai.ngo@oracle.com> wrote:
>>
>> On 3/9/22 12:56 PM, Chuck Lever III wrote:
>>>>> On Mar 4, 2022, at 7:37 PM, Dai Ngo <dai.ngo@oracle.com> wrote:
>>>> Add helper locks_any_blockers to check if there is any blockers
>>>> for a file_lock.
>>>>
>>>> Signed-off-by: Dai Ngo <dai.ngo@oracle.com>
>>>> ---
>>>> include/linux/fs.h | 10 ++++++++++
>>>> 1 file changed, 10 insertions(+)
>>>>
>>>> diff --git a/include/linux/fs.h b/include/linux/fs.h
>>>> index 831b20430d6e..7f5756bfcc13 100644
>>>> --- a/include/linux/fs.h
>>>> +++ b/include/linux/fs.h
>>>> @@ -1200,6 +1200,11 @@ extern void lease_unregister_notifier(struct notifier_block *);
>>>> struct files_struct;
>>>> extern void show_fd_locks(struct seq_file *f,
>>>>              struct file *filp, struct files_struct *files);
>>>> +
>>>> +static inline bool locks_has_blockers_locked(struct file_lock *lck)
>>>> +{
>>>> +    return !list_empty(&lck->fl_blocked_requests);
>>>> +}
>>>> #else /* !CONFIG_FILE_LOCKING */
>>>> static inline int fcntl_getlk(struct file *file, unsigned int cmd,
>>>>                   struct flock __user *user)
>>>> @@ -1335,6 +1340,11 @@ static inline int lease_modify(struct file_lock *fl, int arg,
>>>> struct files_struct;
>>>> static inline void show_fd_locks(struct seq_file *f,
>>>>             struct file *filp, struct files_struct *files) {}
>>>> +
>>>> +static inline bool locks_has_blockers_locked(struct file_lock *lck)
>>>> +{
>>>> +    return false;
>>>> +}
>>>> #endif /* !CONFIG_FILE_LOCKING */
>>>>
>>>> static inline struct inode *file_inode(const struct file *f)
>>> Hm. This is not exactly what I had in mind.
>>>
>>> In order to be more kABI friendly, fl_blocked_requests should be
>>> dereferenced only in fs/locks.c. IMO you want to take the inner
>>> loop in nfs4_lockowner_has_blockers() and make that a function
>>> that lives in fs/locks.c. Something akin to:
>>>
>>> fs/locks.c:
>>>
>>> /**
>>>   * locks_owner_has_blockers - Check for blocking lock requests
>>>   * @flctx: file lock context
>>>   * @owner: lock owner
>>>   *
>>>   * Return values:
>>>   *   %true: @ctx has at least one blocker
>>>   *   %false: @ctx has no blockers
>>>   */
>>> bool locks_owner_has_blockers(struct file_lock_context *flctx,
>>>                   fl_owner_t owner)
>>> {
>>>     struct file_lock *fl;
>>>
>>>     spin_lock(&flctx->flc_lock);
>>>     list_for_each_entry(fl, &flctx->flc_posix, fl_list) {
>>>         if (fl->fl_owner != owner)
>>>             continue;
>>>         if (!list_empty(&fl->fl_blocked_requests)) {
>>>             spin_unlock(&flctx->flc_lock);
>>>             return true;
>>>         }
>>>     }
>>>     spin_unlock(&flctx->flc_lock);
>>>     return false;
>>> }
>>> EXPORT_SYMBOL(locks_owner_has_blockers);
>>>
>>> As a subsequent clean up (which anyone can do at a later point),
>>> a similar change could be done to check_for_locks(). This bit of
>>> code seems to appear in several other filesystems, for example:
>> I used check_for_locks as reference for locks_owner_has_blockers
>> so both should be updated to be more kABI friendly as you suggested.
>> Can I update both in a subsequent cleanup patch?
> No. I prefer that you don’t introduce code and then clean it up later in the same series.
>
> You need to introduce locks_owner_has_blockers() in the same patch where you add the nfsd4_ function that will use it. I think that’s like 7 or 8/11 ? I don’t have it in front of me.

ok, fix in v16.

>
> Because it deduplicates code, cleaning up check_for_locks() will need to involve at least one other site (outside of NFSD) that can make use of this new helper. Therefore I prefer that you wait and do that work after courteous server is merged.

ok.

>
>
>> I plan to have a number of small cleanup up patches for these and also some nits.
> Clean-ups of areas not having to do with courteous server can go in separate patches, but I would prefer to keep clean-ups of the new code in this series integrated together in the same patches with the new code.
>
> Let’s stay focused on finishing the courteous server work and getting it merged.

ok.

Thanks,
-Dai

>
>
>> Thanks,
>> -Dai
>>
>>
>>> 7643         inode = locks_inode(nf->nf_file);
>>> 7644         flctx = inode->i_flctx;
>>> 7645
>>> 7646         if (flctx && !list_empty_careful(&flctx->flc_posix)) {
>>> 7647                 spin_lock(&flctx->flc_lock);
>>> 7648                 list_for_each_entry(fl, &flctx->flc_posix, fl_list) {
>>> 7649                         if (fl->fl_owner == (fl_owner_t)lowner) {
>>> 7650                                 status = true;
>>> 7651                                 break;
>>> 7652                         }
>>> 7653                 }
>>> 7654                 spin_unlock(&flctx->flc_lock);
>>> 7655         }
>>>
>>>
>>> --
>>> Chuck Lever
>>>
>>>
>>>

Re: [PATCH RFC v15 04/11] NFSD: Update nfsd_breaker_owns_lease() to handle courtesy clients

[dai.ngo]

On 3/9/22 1:46 PM, Chuck Lever III wrote:
>
>> On Mar 4, 2022, at 7:37 PM, Dai Ngo <dai.ngo@oracle.com> wrote:
>>
>> Update nfsd_breaker_owns_lease() to handle delegation conflict
>> with courtesy clients. If conflict was caused courtesy client
>> then discard the courtesy client by setting CLIENT_EXPIRED and
>> return conflict resolved. Client with CLIENT_EXPIRED is expired
>> by the laundromat.
>>
>> Signed-off-by: Dai Ngo <dai.ngo@oracle.com>
>> ---
>> fs/nfsd/nfs4state.c | 18 ++++++++++++++++++
>> 1 file changed, 18 insertions(+)
>>
>> diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
>> index 583ac807e98d..40a357fd1a14 100644
>> --- a/fs/nfsd/nfs4state.c
>> +++ b/fs/nfsd/nfs4state.c
>> @@ -4727,6 +4727,24 @@ static bool nfsd_breaker_owns_lease(struct file_lock *fl)
>> 	struct svc_rqst *rqst;
>> 	struct nfs4_client *clp;
>>
>> +	clp = dl->dl_stid.sc_client;
>> +	/*
>> +	 * need to sync with courtesy client trying to reconnect using
>> +	 * the cl_cs_lock, nn->client_lock can not be used since this
>> +	 * function is called with the fl_lck held.
>> +	 */
>> +	spin_lock(&clp->cl_cs_lock);
>> +	if (test_bit(NFSD4_CLIENT_EXPIRED, &clp->cl_flags)) {
>> +		spin_unlock(&clp->cl_cs_lock);
>> +		return true;
>> +	}
>> +	if (test_bit(NFSD4_CLIENT_COURTESY, &clp->cl_flags)) {
>> +		set_bit(NFSD4_CLIENT_EXPIRED, &clp->cl_flags);
>> +		spin_unlock(&clp->cl_cs_lock);
>> +		return true;
>> +	}
>> +	spin_unlock(&clp->cl_cs_lock);
>> +
> Nit: Please add nfs4_check_and_expire_courtesy_client() in this patch
> instead of in 05/11.

That means nfs4_check_and_expire_courtesy_client is being called
in 05/11 but is not defined in 05/11. Is that ok?

-Dai

>
>
>> 	if (!i_am_nfsd())
>> 		return false;
>> 	rqst = kthread_data(current);
>> -- 
>> 2.9.5
>>
> --
> Chuck Lever
>
>
>

Re: [PATCH RFC v15 04/11] NFSD: Update nfsd_breaker_owns_lease() to handle courtesy clients

[Chuck Lever III]

> On Mar 10, 2022, at 12:09 AM, Dai Ngo <dai.ngo@oracle.com> wrote:
> 
> 
> On 3/9/22 1:46 PM, Chuck Lever III wrote:
>> 
>>> On Mar 4, 2022, at 7:37 PM, Dai Ngo <dai.ngo@oracle.com> wrote:
>>> 
>>> Update nfsd_breaker_owns_lease() to handle delegation conflict
>>> with courtesy clients. If conflict was caused courtesy client
>>> then discard the courtesy client by setting CLIENT_EXPIRED and
>>> return conflict resolved. Client with CLIENT_EXPIRED is expired
>>> by the laundromat.
>>> 
>>> Signed-off-by: Dai Ngo <dai.ngo@oracle.com>
>>> ---
>>> fs/nfsd/nfs4state.c | 18 ++++++++++++++++++
>>> 1 file changed, 18 insertions(+)
>>> 
>>> diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
>>> index 583ac807e98d..40a357fd1a14 100644
>>> --- a/fs/nfsd/nfs4state.c
>>> +++ b/fs/nfsd/nfs4state.c
>>> @@ -4727,6 +4727,24 @@ static bool nfsd_breaker_owns_lease(struct file_lock *fl)
>>> 	struct svc_rqst *rqst;
>>> 	struct nfs4_client *clp;
>>> 
>>> +	clp = dl->dl_stid.sc_client;
>>> +	/*
>>> +	 * need to sync with courtesy client trying to reconnect using
>>> +	 * the cl_cs_lock, nn->client_lock can not be used since this
>>> +	 * function is called with the fl_lck held.
>>> +	 */
>>> +	spin_lock(&clp->cl_cs_lock);
>>> +	if (test_bit(NFSD4_CLIENT_EXPIRED, &clp->cl_flags)) {
>>> +		spin_unlock(&clp->cl_cs_lock);
>>> +		return true;
>>> +	}
>>> +	if (test_bit(NFSD4_CLIENT_COURTESY, &clp->cl_flags)) {
>>> +		set_bit(NFSD4_CLIENT_EXPIRED, &clp->cl_flags);
>>> +		spin_unlock(&clp->cl_cs_lock);
>>> +		return true;
>>> +	}
>>> +	spin_unlock(&clp->cl_cs_lock);
>>> +
>> Nit: Please add nfs4_check_and_expire_courtesy_client() in this patch
>> instead of in 05/11.
> 
> That means nfs4_check_and_expire_courtesy_client is being called
> in 05/11 but is not defined in 05/11. Is that ok?

I thought I saw a hunk in 5/11 that converts nfsd_breaker_owns_lease()
to use nfs4_check_and_expire_courtesy_client().

If so, I prefer if you add nfs4_check_and_expire_courtesy_client() in
this patch, and call it from nfsd_breaker_owns_lease(). Then the
additional clean-up in 5/11 isn't needed.

Again, this is a nit. But since you are driving a v16 soon anyway,
I'd like the patches changed before they are merged.


> -Dai
> 
>> 
>> 
>>> 	if (!i_am_nfsd())
>>> 		return false;
>>> 	rqst = kthread_data(current);
>>> -- 
>>> 2.9.5
>>> 
>> --
>> Chuck Lever
>> 
>> 
>> 

--
Chuck Lever

Re: [PATCH RFC v15 11/11] NFSD: Show state of courtesy clients in client info

[Chuck Lever III]

> On Mar 9, 2022, at 10:09 PM, Dai Ngo <dai.ngo@oracle.com> wrote:
> 
> 
> On 3/9/22 12:51 PM, dai.ngo@oracle.com wrote:
>> 
>> On 3/9/22 12:14 PM, Chuck Lever III wrote:
>>> 
>>>> On Mar 4, 2022, at 7:37 PM, Dai Ngo <dai.ngo@oracle.com> wrote:
>>>> 
>>>> Update client_info_show to show state of courtesy client
>>>> and time since last renew.
>>>> 
>>>> Signed-off-by: Dai Ngo <dai.ngo@oracle.com>
>>>> ---
>>>> fs/nfsd/nfs4state.c | 9 ++++++++-
>>>> 1 file changed, 8 insertions(+), 1 deletion(-)
>>>> 
>>>> diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
>>>> index bced09014e6b..ed14e0b54537 100644
>>>> --- a/fs/nfsd/nfs4state.c
>>>> +++ b/fs/nfsd/nfs4state.c
>>>> @@ -2439,7 +2439,8 @@ static int client_info_show(struct seq_file *m, void *v)
>>>> {
>>>>     struct inode *inode = m->private;
>>>>     struct nfs4_client *clp;
>>>> -    u64 clid;
>>>> +    u64 clid, hrs;
>>>> +    u32 mins, secs;
>>>> 
>>>>     clp = get_nfsdfs_clp(inode);
>>>>     if (!clp)
>>>> @@ -2451,6 +2452,12 @@ static int client_info_show(struct seq_file *m, void *v)
>>>>         seq_puts(m, "status: confirmed\n");
>>>>     else
>>>>         seq_puts(m, "status: unconfirmed\n");
>>>> +    seq_printf(m, "courtesy client: %s\n",
>>>> +        test_bit(NFSD4_CLIENT_COURTESY, &clp->cl_flags) ? "yes" : "no");
>>> I'm wondering if it would be more economical to combine this
>>> output with the status output just before it so we have only
>>> one of:
>>> 
>>>     seq_puts(m, "status: unconfirmed\n");
>>> 
>>>     seq_puts(m, "status: confirmed\n");
>>> 
>>> or
>>> 
>>>     seq_puts(m, "status: courtesy\n");
>> 
>> make sense, will fix.
> 
> On second thought, I think it's safer to keep this the same
> since there might be scripts out there that depend on it.

The "status:" information was added just a year ago by
472d155a0631 ("nfsd: report client confirmation status
in "info" file"). I don't see any concern in recent commit
history about making the information in this file
machine-readable or backwards-compatible.

Therefore IMO it should be safe and acceptable to use:

  status: confirmed|unconfirmed|courtesy


> -Dai
> 
>> 
>>> 
>>> 
>>>> +    hrs = div_u64_rem(ktime_get_boottime_seconds() - clp->cl_time,
>>>> +                3600, &secs);
>>>> +    mins = div_u64_rem((u64)secs, 60, &secs);
>>>> +    seq_printf(m, "time since last renew: %02ld:%02d:%02d\n", hrs, mins, secs);
>>> Thanks, this seems more friendly than what was here before.
>>> 
>>> However if we replace the fixed courtesy timeout with a
>>> shrinker, I bet some courtesy clients might lie about for
>>> many more that 99 hours. Perhaps the left-most format
>>> specifier could be just "%lu" and the rest could be "%02u".
>>> 
>>> (ie, also turn the "d" into "u" to prevent ever displaying
>>> a negative number of time units).
>> 
>> will fix.
>> 
>> I will wait for your review of the rest of the patches before
>> I submit v16.
>> 
>> Thanks,
>> -Dai
>> 
>>> 
>>> 
>>>>     seq_printf(m, "name: ");
>>>>     seq_quote_mem(m, clp->cl_name.data, clp->cl_name.len);
>>>>     seq_printf(m, "\nminor version: %d\n", clp->cl_minorversion);
>>>> -- 
>>>> 2.9.5
>>>> 
>>> -- 
>>> Chuck Lever
>>> 
>>> 
>>> 

--
Chuck Lever

Re: [PATCH RFC v15 11/11] NFSD: Show state of courtesy clients in client info

[Bruce Fields]

On Thu, Mar 10, 2022 at 03:27:58AM +0000, Chuck Lever III wrote:
> 
> > On Mar 9, 2022, at 10:09 PM, Dai Ngo <dai.ngo@oracle.com> wrote:
> > 
> > 
> >> On 3/9/22 12:51 PM, dai.ngo@oracle.com wrote:
> >> 
> >>> On 3/9/22 12:14 PM, Chuck Lever III wrote:
> >>> 
> >>>> On Mar 4, 2022, at 7:37 PM, Dai Ngo <dai.ngo@oracle.com> wrote:
> >>>> 
> >>>> Update client_info_show to show state of courtesy client and time
> >>>> since last renew.
> >>>> 
> >>>> Signed-off-by: Dai Ngo <dai.ngo@oracle.com> ---
> >>>> fs/nfsd/nfs4state.c | 9 ++++++++- 1 file changed, 8
> >>>> insertions(+), 1 deletion(-)
> >>>> 
> >>>> diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c index
> >>>> bced09014e6b..ed14e0b54537 100644 --- a/fs/nfsd/nfs4state.c +++
> >>>> b/fs/nfsd/nfs4state.c @@ -2439,7 +2439,8 @@ static int
> >>>> client_info_show(struct seq_file *m, void *v) { struct inode
> >>>> *inode = m->private; struct nfs4_client *clp; -    u64 clid; +
> >>>> u64 clid, hrs; +    u32 mins, secs;
> >>>> 
> >>>>     clp = get_nfsdfs_clp(inode); if (!clp) @@ -2451,6 +2452,12 @@
> >>>>     static int client_info_show(struct seq_file *m, void *v)
> >>>>     seq_puts(m, "status: confirmed\n"); else seq_puts(m, "status:
> >>>>     unconfirmed\n"); +    seq_printf(m, "courtesy client: %s\n",
> >>>>     +        test_bit(NFSD4_CLIENT_COURTESY, &clp->cl_flags) ?
> >>>>     "yes" : "no");
> >>> I'm wondering if it would be more economical to combine this
> >>> output with the status output just before it so we have only one
> >>> of:
> >>> 
> >>>     seq_puts(m, "status: unconfirmed\n");
> >>> 
> >>>     seq_puts(m, "status: confirmed\n");
> >>> 
> >>> or
> >>> 
> >>>     seq_puts(m, "status: courtesy\n");
> >> 
> >> make sense, will fix.
> > 
> > On second thought, I think it's safer to keep this the same since
> > there might be scripts out there that depend on it.
> 
> I agree we should be sensitive to potential users of this information.
> However…
> 
> Without having one or two examples of such scripts in front of us,
> it’s hard to say whether my suggestion (a new keyword after “status:”)
> or your original (a new line in the file) would be more disruptive.
> 
> Also I’m not seeing exactly how the output format is versioned… so
> what’s the safest way to make changes to the output format of this
> file? Anyone?

It's not versioned.  It'd be good to document some rules; nfsd(7) seems
like the logical place to put that, though probably knows about it.
Pointers to it from kernel comments and elsewhere might help?

I suppose the absolute safest option would be adding a new line, but I
like the idea of adding the possibility of "courtesy" to the existing
line as you suggest, and that seems very low risk.

There is one utility, see nfs-utils/tools/nfsdclnt.  I'd forgotten about
it untill I looked just now....

--b.

Re: [PATCH RFC v15 11/11] NFSD: Show state of courtesy clients in client info

[dai.ngo]

On 3/10/22 7:00 AM, Bruce Fields wrote:
> On Thu, Mar 10, 2022 at 03:27:58AM +0000, Chuck Lever III wrote:
>>> On Mar 9, 2022, at 10:09 PM, Dai Ngo <dai.ngo@oracle.com> wrote:
>>>
>>> 
>>>> On 3/9/22 12:51 PM, dai.ngo@oracle.com wrote:
>>>>
>>>>> On 3/9/22 12:14 PM, Chuck Lever III wrote:
>>>>>
>>>>>> On Mar 4, 2022, at 7:37 PM, Dai Ngo <dai.ngo@oracle.com> wrote:
>>>>>>
>>>>>> Update client_info_show to show state of courtesy client and time
>>>>>> since last renew.
>>>>>>
>>>>>> Signed-off-by: Dai Ngo <dai.ngo@oracle.com> ---
>>>>>> fs/nfsd/nfs4state.c | 9 ++++++++- 1 file changed, 8
>>>>>> insertions(+), 1 deletion(-)
>>>>>>
>>>>>> diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c index
>>>>>> bced09014e6b..ed14e0b54537 100644 --- a/fs/nfsd/nfs4state.c +++
>>>>>> b/fs/nfsd/nfs4state.c @@ -2439,7 +2439,8 @@ static int
>>>>>> client_info_show(struct seq_file *m, void *v) { struct inode
>>>>>> *inode = m->private; struct nfs4_client *clp; -    u64 clid; +
>>>>>> u64 clid, hrs; +    u32 mins, secs;
>>>>>>
>>>>>>      clp = get_nfsdfs_clp(inode); if (!clp) @@ -2451,6 +2452,12 @@
>>>>>>      static int client_info_show(struct seq_file *m, void *v)
>>>>>>      seq_puts(m, "status: confirmed\n"); else seq_puts(m, "status:
>>>>>>      unconfirmed\n"); +    seq_printf(m, "courtesy client: %s\n",
>>>>>>      +        test_bit(NFSD4_CLIENT_COURTESY, &clp->cl_flags) ?
>>>>>>      "yes" : "no");
>>>>> I'm wondering if it would be more economical to combine this
>>>>> output with the status output just before it so we have only one
>>>>> of:
>>>>>
>>>>>      seq_puts(m, "status: unconfirmed\n");
>>>>>
>>>>>      seq_puts(m, "status: confirmed\n");
>>>>>
>>>>> or
>>>>>
>>>>>      seq_puts(m, "status: courtesy\n");
>>>> make sense, will fix.
>>> On second thought, I think it's safer to keep this the same since
>>> there might be scripts out there that depend on it.
>> I agree we should be sensitive to potential users of this information.
>> However…
>>
>> Without having one or two examples of such scripts in front of us,
>> it’s hard to say whether my suggestion (a new keyword after “status:”)
>> or your original (a new line in the file) would be more disruptive.
>>
>> Also I’m not seeing exactly how the output format is versioned… so
>> what’s the safest way to make changes to the output format of this
>> file? Anyone?
> It's not versioned.  It'd be good to document some rules; nfsd(7) seems
> like the logical place to put that, though probably knows about it.
> Pointers to it from kernel comments and elsewhere might help?
>
> I suppose the absolute safest option would be adding a new line, but I
> like the idea of adding the possibility of "courtesy" to the existing
> line as you suggest, and that seems very low risk.
>
> There is one utility, see nfs-utils/tools/nfsdclnt.  I'd forgotten about
> it untill I looked just now....

I think nfsdclnt does not parse the 'status' field so we're safe to
update the status to show 'confirmed/unconfirmed/courtesy'.

-Dai

>
> --b.