2 /* vnode and volume validity verification.
19  *  (2) On a RW volume, in response to certain vnode (inode)-accessing RPC
27  *  (3) On a RO (or Backup) volume, in response to certain vnode-accessing RPC
28  *      calls, each server maintains a time-limited per-volume promise that it
29  *      will send us a CB.CallBack request if the RO volume is updated to a
30  *      snapshot of the RW volume ("vos release").  This is an atomic event
31  *      that cuts over all instances of the RO volume across multiple servers
34  *	Note that a volume-level callbacks may also be sent for other reasons,
35  *	such as the volumeserver taking over control of the volume from the
41  *  (4) Certain RPC calls include a volume information record "VolSync" in
42  *      their reply.  This contains a creation date for the volume that should
43  *      remain unchanged for a RW volume (but will be changed if the volume is
45  *      when a RO volume is released.
50  *	a volume have been altered since we last checked a vnode.
60  *      recognised that a RO volume has been updated.
70  *  (1) When a volume-level CB.CallBack occurs, we increment ->cb_v_break on
71  *      the volume and reset ->cb_expires_at (ie. set AFS_NO_CB_PROMISE) on the
72  *      volume and volume's server record.
74  *  (2) When a CB.InitCallBackState occurs, we treat this as a volume-level
75  *	callback break on all the volumes that have been using that volume
85  *	->cb_v_break match, and if they don't, we lock volume->cb_check_lock
88  *	After checking the volume, we check the vnode.  If there's a mismatch
89  *	between the volume counters and the vnode's mirrors of those counters,
95  *	(A) If the Creation timestamp has changed on a RW volume or regressed
96  *	    on a RO volume, we try to increment ->cb_scrub; if it advances on a
97  *	    RO volume, we assume "vos release" happened and try to increment
107  *	volume->cb_v_check is then set to ->cb_v_break.
111  *	the volume and the volume's server record.
118  * Check the validity of a vnode/inode and its parent volume.
122 	const struct afs_volume *volume = vnode->volume;  in afs_check_validity()  local
125 	if (atomic_read(&volume->cb_v_check) != atomic_read(&volume->cb_v_break) ||  in afs_check_validity()
127 	    volume->cb_expires_at <= deadline ||  in afs_check_validity()
128 	    vnode->cb_ro_snapshot != atomic_read(&volume->cb_ro_snapshot) ||  in afs_check_validity()
129 	    vnode->cb_scrub	  != atomic_read(&volume->cb_scrub) ||  in afs_check_validity()
141 static bool __afs_is_server_excluded(struct afs_operation *op, struct afs_volume *volume)  in __afs_is_server_excluded()  argument
150 	slist = rcu_dereference(volume->servers);  in __afs_is_server_excluded()
164  * Update the volume's server list when the creation time changes and see if
167 static int afs_is_server_excluded(struct afs_operation *op, struct afs_volume *volume)  in afs_is_server_excluded()  argument
171 	if (__afs_is_server_excluded(op, volume))  in afs_is_server_excluded()
174 	set_bit(AFS_VOLUME_NEEDS_UPDATE, &volume->flags);  in afs_is_server_excluded()
175 	ret = afs_check_volume_status(op->volume, op);  in afs_is_server_excluded()
179 	return __afs_is_server_excluded(op, volume);  in afs_is_server_excluded()
183  * Handle a change to the volume creation time in the VolSync record.
185 static int afs_update_volume_creation_time(struct afs_operation *op, struct afs_volume *volume)  in afs_update_volume_creation_time()  argument
188 	time64_t cur = volume->creation_time;  in afs_update_volume_creation_time()
193 	_enter("%llx,%llx,%llx->%llx", volume->vid, cur, old, new);  in afs_update_volume_creation_time()
196 		volume->creation_time = new;  in afs_update_volume_creation_time()
212 	 * our caches.  For a RW vol, this will only change if the volume is  in afs_update_volume_creation_time()
214 	 * the volume is updated to a new snapshot (eg. "vos release").  in afs_update_volume_creation_time()
216 	if (volume->type == AFSVL_RWVOL)  in afs_update_volume_creation_time()
218 	if (volume->type == AFSVL_BACKVOL) {  in afs_update_volume_creation_time()
224 	/* We have an RO volume, we need to query the VL server and look at the  in afs_update_volume_creation_time()
227 	ret = afs_is_server_excluded(op, volume);  in afs_update_volume_creation_time()
231 		snap = atomic_read(&volume->cb_ro_snapshot);  in afs_update_volume_creation_time()
232 		trace_afs_cb_v_break(volume->vid, snap, afs_cb_break_volume_excluded);  in afs_update_volume_creation_time()
237 	snap = atomic_inc_return(&volume->cb_ro_snapshot);  in afs_update_volume_creation_time()
238 	trace_afs_cb_v_break(volume->vid, snap, afs_cb_break_for_vos_release);  in afs_update_volume_creation_time()
239 	volume->creation_time = new;  in afs_update_volume_creation_time()
243 	atomic_inc(&volume->cb_scrub);  in afs_update_volume_creation_time()
244 	trace_afs_cb_v_break(volume->vid, 0, afs_cb_break_for_creation_regress);  in afs_update_volume_creation_time()
245 	volume->creation_time = new;  in afs_update_volume_creation_time()
250  * Handle a change to the volume update time in the VolSync record.
252 static void afs_update_volume_update_time(struct afs_operation *op, struct afs_volume *volume)  in afs_update_volume_update_time()  argument
255 	time64_t cur = volume->update_time;  in afs_update_volume_update_time()
259 	_enter("%llx,%llx,%llx->%llx", volume->vid, cur, old, new);  in afs_update_volume_update_time()
262 		volume->update_time = new;  in afs_update_volume_update_time()
269 	/* If the volume update time changes in an unexpected way, we need to  in afs_update_volume_update_time()
272 	 * volume is updated to a new snapshot (eg. "vos release").  in afs_update_volume_update_time()
284 			atomic_inc(&volume->cb_scrub);  in afs_update_volume_update_time()
285 			trace_afs_cb_v_break(volume->vid, 0, reason);  in afs_update_volume_update_time()
287 		volume->update_time = new;  in afs_update_volume_update_time()
291 static int afs_update_volume_times(struct afs_operation *op, struct afs_volume *volume)  in afs_update_volume_times()  argument
295 	if (likely(op->volsync.creation == volume->creation_time &&  in afs_update_volume_times()
296 		   op->volsync.update == volume->update_time))  in afs_update_volume_times()
299 	mutex_lock(&volume->volsync_lock);  in afs_update_volume_times()
300 	if (op->volsync.creation != volume->creation_time) {  in afs_update_volume_times()
301 		ret = afs_update_volume_creation_time(op, volume);  in afs_update_volume_times()
305 	if (op->volsync.update != volume->update_time)  in afs_update_volume_times()
306 		afs_update_volume_update_time(op, volume);  in afs_update_volume_times()
308 	mutex_unlock(&volume->volsync_lock);  in afs_update_volume_times()
313  * Update the state of a volume, including recording the expiration time of the
321 	struct afs_volume *volume = op->volume;  in afs_update_volume_state()  local
322 	unsigned int cb_v_break = atomic_read(&volume->cb_v_break);  in afs_update_volume_state()
323 	unsigned int cb_v_check = atomic_read(&volume->cb_v_check);  in afs_update_volume_state()
326 	_enter("%llx", op->volume->vid);  in afs_update_volume_state()
329 		ret = afs_update_volume_times(op, volume);  in afs_update_volume_state()
344 		volume->cb_expires_at = expires_at;  in afs_update_volume_state()
347 		atomic_cmpxchg(&volume->cb_v_check, cb_v_check, op->cb_v_break);  in afs_update_volume_state()
381 	struct afs_volume *volume = vnode->volume;  in afs_validate()  local
398 	/* Validate a volume after the v_break has changed or the volume  in afs_validate()
399 	 * callback expired.  We only want to do this once per volume per  in afs_validate()
403 	if (volume->cb_expires_at <= deadline ||  in afs_validate()
404 	    atomic_read(&volume->cb_v_check) != atomic_read(&volume->cb_v_break)) {  in afs_validate()
405 		ret = mutex_lock_interruptible(&volume->cb_check_lock);  in afs_validate()
411 	cb_ro_snapshot = atomic_read(&volume->cb_ro_snapshot);  in afs_validate()
412 	cb_scrub = atomic_read(&volume->cb_scrub);  in afs_validate()
419 	    volume->cb_expires_at <= deadline ||  in afs_validate()
420 	    atomic_read(&volume->cb_v_check) != atomic_read(&volume->cb_v_break) ||  in afs_validate()
435 	/* We can drop the volume lock now as. */  in afs_validate()
437 		mutex_unlock(&volume->cb_check_lock);  in afs_validate()
441 	cb_ro_snapshot = atomic_read(&volume->cb_ro_snapshot);  in afs_validate()
442 	cb_scrub = atomic_read(&volume->cb_scrub);  in afs_validate()
468 		mutex_unlock(&volume->cb_check_lock);  in afs_validate()