1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * (C) 2001 Clemson University and The University of Chicago
4  * (C) 2011 Omnibond Systems
5  *
6  * Changes by Acxiom Corporation to implement generic service_operation()
7  * function, Copyright Acxiom Corporation, 2005.
8  *
9  * See COPYING in top-level directory.
10  */
11 
12 /*
13  *  In-kernel waitqueue operations.
14  */
15 
16 #include "protocol.h"
17 #include "orangefs-kernel.h"
18 #include "orangefs-bufmap.h"
19 
20 static int wait_for_matching_downcall(struct orangefs_kernel_op_s *op,
21 		long timeout,
22 		int flags)
23 			__acquires(op->lock);
24 static void orangefs_clean_up_interrupted_operation(struct orangefs_kernel_op_s *op)
25 	__releases(op->lock);
26 
27 /*
28  * What we do in this function is to walk the list of operations that are
29  * present in the request queue and mark them as purged.
30  * NOTE: This is called from the device close after client-core has
31  * guaranteed that no new operations could appear on the list since the
32  * client-core is anyway going to exit.
33  */
purge_waiting_ops(void)34 void purge_waiting_ops(void)
35 {
36 	struct orangefs_kernel_op_s *op, *tmp;
37 
38 	spin_lock(&orangefs_request_list_lock);
39 	list_for_each_entry_safe(op, tmp, &orangefs_request_list, list) {
40 		gossip_debug(GOSSIP_WAIT_DEBUG,
41 			     "pvfs2-client-core: purging op tag %llu %s\n",
42 			     llu(op->tag),
43 			     get_opname_string(op));
44 		set_op_state_purged(op);
45 		gossip_debug(GOSSIP_DEV_DEBUG,
46 			     "%s: op:%s: op_state:%d: process:%s:\n",
47 			     __func__,
48 			     get_opname_string(op),
49 			     op->op_state,
50 			     current->comm);
51 	}
52 	spin_unlock(&orangefs_request_list_lock);
53 }
54 
55 /*
56  * submits a ORANGEFS operation and waits for it to complete
57  *
58  * Note op->downcall.status will contain the status of the operation (in
59  * errno format), whether provided by pvfs2-client or a result of failure to
60  * service the operation.  If the caller wishes to distinguish, then
61  * op->state can be checked to see if it was serviced or not.
62  *
63  * Returns contents of op->downcall.status for convenience
64  */
service_operation(struct orangefs_kernel_op_s * op,const char * op_name,int flags)65 int service_operation(struct orangefs_kernel_op_s *op,
66 		      const char *op_name,
67 		      int flags)
68 {
69 	long timeout = MAX_SCHEDULE_TIMEOUT;
70 	int ret = 0;
71 
72 	DEFINE_WAIT(wait_entry);
73 
74 	op->upcall.tgid = current->tgid;
75 	op->upcall.pid = current->pid;
76 
77 retry_servicing:
78 	op->downcall.status = 0;
79 	gossip_debug(GOSSIP_WAIT_DEBUG,
80 		     "%s: %s op:%p: process:%s: pid:%d:\n",
81 		     __func__,
82 		     op_name,
83 		     op,
84 		     current->comm,
85 		     current->pid);
86 
87 	/*
88 	 * If ORANGEFS_OP_NO_MUTEX was set in flags, we need to avoid
89 	 * acquiring the request_mutex because we're servicing a
90 	 * high priority remount operation and the request_mutex is
91 	 * already taken.
92 	 */
93 	if (!(flags & ORANGEFS_OP_NO_MUTEX)) {
94 		if (flags & ORANGEFS_OP_INTERRUPTIBLE)
95 			ret = mutex_lock_interruptible(&orangefs_request_mutex);
96 		else
97 			ret = mutex_lock_killable(&orangefs_request_mutex);
98 		/*
99 		 * check to see if we were interrupted while waiting for
100 		 * mutex
101 		 */
102 		if (ret < 0) {
103 			op->downcall.status = ret;
104 			gossip_debug(GOSSIP_WAIT_DEBUG,
105 				     "%s: service_operation interrupted.\n",
106 				     __func__);
107 			return ret;
108 		}
109 	}
110 
111 	/* queue up the operation */
112 	spin_lock(&orangefs_request_list_lock);
113 	spin_lock(&op->lock);
114 	set_op_state_waiting(op);
115 	gossip_debug(GOSSIP_DEV_DEBUG,
116 		     "%s: op:%s: op_state:%d: process:%s:\n",
117 		     __func__,
118 		     get_opname_string(op),
119 		     op->op_state,
120 		     current->comm);
121 	/* add high priority remount op to the front of the line. */
122 	if (flags & ORANGEFS_OP_PRIORITY)
123 		list_add(&op->list, &orangefs_request_list);
124 	else
125 		list_add_tail(&op->list, &orangefs_request_list);
126 	spin_unlock(&op->lock);
127 	wake_up_interruptible(&orangefs_request_list_waitq);
128 	if (!__is_daemon_in_service()) {
129 		gossip_debug(GOSSIP_WAIT_DEBUG,
130 			     "%s:client core is NOT in service.\n",
131 			     __func__);
132 		/*
133 		 * Don't wait for the userspace component to return if
134 		 * the filesystem is being umounted anyway.
135 		 */
136 		if (op->upcall.type == ORANGEFS_VFS_OP_FS_UMOUNT)
137 			timeout = 0;
138 		else
139 			timeout = op_timeout_secs * HZ;
140 	}
141 	spin_unlock(&orangefs_request_list_lock);
142 
143 	if (!(flags & ORANGEFS_OP_NO_MUTEX))
144 		mutex_unlock(&orangefs_request_mutex);
145 
146 	ret = wait_for_matching_downcall(op, timeout, flags);
147 	gossip_debug(GOSSIP_WAIT_DEBUG,
148 		     "%s: wait_for_matching_downcall returned %d for %p\n",
149 		     __func__,
150 		     ret,
151 		     op);
152 
153 	/* got matching downcall; make sure status is in errno format */
154 	if (!ret) {
155 		spin_unlock(&op->lock);
156 		op->downcall.status =
157 		    orangefs_normalize_to_errno(op->downcall.status);
158 		ret = op->downcall.status;
159 		goto out;
160 	}
161 
162 	/* failed to get matching downcall */
163 	if (ret == -ETIMEDOUT) {
164 		gossip_err("%s: %s -- wait timed out; aborting attempt.\n",
165 			   __func__,
166 			   op_name);
167 	}
168 
169 	/*
170 	 * remove a waiting op from the request list or
171 	 * remove an in-progress op from the in-progress list.
172 	 */
173 	orangefs_clean_up_interrupted_operation(op);
174 
175 	op->downcall.status = ret;
176 	/* retry if operation has not been serviced and if requested */
177 	if (ret == -EAGAIN) {
178 		op->attempts++;
179 		timeout = op_timeout_secs * HZ;
180 		gossip_debug(GOSSIP_WAIT_DEBUG,
181 			     "orangefs: tag %llu (%s)"
182 			     " -- operation to be retried (%d attempt)\n",
183 			     llu(op->tag),
184 			     op_name,
185 			     op->attempts);
186 
187 		/*
188 		 * io ops (ops that use the shared memory buffer) have
189 		 * to be returned to their caller for a retry. Other ops
190 		 * can just be recycled here.
191 		 */
192 		if (!op->uses_shared_memory)
193 			goto retry_servicing;
194 	}
195 
196 out:
197 	gossip_debug(GOSSIP_WAIT_DEBUG,
198 		     "%s: %s returning: %d for %p.\n",
199 		     __func__,
200 		     op_name,
201 		     ret,
202 		     op);
203 	return ret;
204 }
205 
206 /* This can get called on an I/O op if it had a bad service_operation. */
orangefs_cancel_op_in_progress(struct orangefs_kernel_op_s * op)207 bool orangefs_cancel_op_in_progress(struct orangefs_kernel_op_s *op)
208 {
209 	u64 tag = op->tag;
210 	if (!op_state_in_progress(op))
211 		return false;
212 
213 	op->slot_to_free = op->upcall.req.io.buf_index;
214 	memset(&op->upcall, 0, sizeof(op->upcall));
215 	memset(&op->downcall, 0, sizeof(op->downcall));
216 	op->upcall.type = ORANGEFS_VFS_OP_CANCEL;
217 	op->upcall.req.cancel.op_tag = tag;
218 	op->downcall.type = ORANGEFS_VFS_OP_INVALID;
219 	op->downcall.status = -1;
220 	orangefs_new_tag(op);
221 
222 	spin_lock(&orangefs_request_list_lock);
223 	/* orangefs_request_list_lock is enough of a barrier here */
224 	if (!__is_daemon_in_service()) {
225 		spin_unlock(&orangefs_request_list_lock);
226 		return false;
227 	}
228 	spin_lock(&op->lock);
229 	set_op_state_waiting(op);
230 	gossip_debug(GOSSIP_DEV_DEBUG,
231 		     "%s: op:%s: op_state:%d: process:%s:\n",
232 		     __func__,
233 		     get_opname_string(op),
234 		     op->op_state,
235 		     current->comm);
236 	list_add(&op->list, &orangefs_request_list);
237 	spin_unlock(&op->lock);
238 	spin_unlock(&orangefs_request_list_lock);
239 
240 	gossip_debug(GOSSIP_WAIT_DEBUG,
241 		     "Attempting ORANGEFS operation cancellation of tag %llu\n",
242 		     llu(tag));
243 	return true;
244 }
245 
246 /*
247  * Change an op to the "given up" state and remove it from its list.
248  */
249 static void
orangefs_clean_up_interrupted_operation(struct orangefs_kernel_op_s * op)250 	orangefs_clean_up_interrupted_operation(struct orangefs_kernel_op_s *op)
251 		__releases(op->lock)
252 {
253 	/*
254 	 * handle interrupted cases depending on what state we were in when
255 	 * the interruption is detected.
256 	 *
257 	 * Called with op->lock held.
258 	 */
259 
260 	/*
261 	 * List manipulation code elsewhere will ignore ops that
262 	 * have been given up upon.
263 	 */
264 	op->op_state |= OP_VFS_STATE_GIVEN_UP;
265 
266 	if (list_empty(&op->list)) {
267 		/* caught copying to/from daemon */
268 		BUG_ON(op_state_serviced(op));
269 		spin_unlock(&op->lock);
270 		wait_for_completion(&op->waitq);
271 	} else if (op_state_waiting(op)) {
272 		/*
273 		 * upcall hasn't been read; remove op from upcall request
274 		 * list.
275 		 */
276 		spin_unlock(&op->lock);
277 		spin_lock(&orangefs_request_list_lock);
278 		list_del_init(&op->list);
279 		spin_unlock(&orangefs_request_list_lock);
280 		gossip_debug(GOSSIP_WAIT_DEBUG,
281 			     "Interrupted: Removed op %p from request_list\n",
282 			     op);
283 	} else if (op_state_in_progress(op)) {
284 		/* op must be removed from the in progress htable */
285 		spin_unlock(&op->lock);
286 		spin_lock(&orangefs_htable_ops_in_progress_lock);
287 		list_del_init(&op->list);
288 		spin_unlock(&orangefs_htable_ops_in_progress_lock);
289 		gossip_debug(GOSSIP_WAIT_DEBUG,
290 			     "Interrupted: Removed op %p"
291 			     " from htable_ops_in_progress\n",
292 			     op);
293 	} else {
294 		spin_unlock(&op->lock);
295 		gossip_err("interrupted operation is in a weird state 0x%x\n",
296 			   op->op_state);
297 	}
298 	reinit_completion(&op->waitq);
299 }
300 
301 /*
302  * Sleeps on waitqueue waiting for matching downcall.
303  * If client-core finishes servicing, then we are good to go.
304  * else if client-core exits, we get woken up here, and retry with a timeout
305  *
306  * When this call returns to the caller, the specified op will no
307  * longer be in either the in_progress hash table or on the request list.
308  *
309  * Returns 0 on success and -errno on failure
310  * Errors are:
311  * EAGAIN in case we want the caller to requeue and try again..
312  * EINTR/EIO/ETIMEDOUT indicating we are done trying to service this
313  * operation since client-core seems to be exiting too often
314  * or if we were interrupted.
315  *
316  * Returns with op->lock taken.
317  */
wait_for_matching_downcall(struct orangefs_kernel_op_s * op,long timeout,int flags)318 static int wait_for_matching_downcall(struct orangefs_kernel_op_s *op,
319 		long timeout,
320 		int flags)
321 			__acquires(op->lock)
322 {
323 	long n;
324 	int writeback = flags & ORANGEFS_OP_WRITEBACK,
325 	    interruptible = flags & ORANGEFS_OP_INTERRUPTIBLE;
326 
327 	/*
328 	 * There's a "schedule_timeout" inside of these wait
329 	 * primitives, during which the op is out of the hands of the
330 	 * user process that needs something done and is being
331 	 * manipulated by the client-core process.
332 	 */
333 	if (writeback)
334 		n = wait_for_completion_io_timeout(&op->waitq, timeout);
335 	else if (!writeback && interruptible)
336 		n = wait_for_completion_interruptible_timeout(&op->waitq,
337 								      timeout);
338 	else /* !writeback && !interruptible but compiler complains */
339 		n = wait_for_completion_killable_timeout(&op->waitq, timeout);
340 
341 	spin_lock(&op->lock);
342 
343 	if (op_state_serviced(op))
344 		return 0;
345 
346 	if (unlikely(n < 0)) {
347 		gossip_debug(GOSSIP_WAIT_DEBUG,
348 			     "%s: operation interrupted, tag %llu, %p\n",
349 			     __func__,
350 			     llu(op->tag),
351 			     op);
352 		return -EINTR;
353 	}
354 	if (op_state_purged(op)) {
355 		gossip_debug(GOSSIP_WAIT_DEBUG,
356 			     "%s: operation purged, tag %llu, %p, %d\n",
357 			     __func__,
358 			     llu(op->tag),
359 			     op,
360 			     op->attempts);
361 		return (op->attempts < ORANGEFS_PURGE_RETRY_COUNT) ?
362 			 -EAGAIN :
363 			 -EIO;
364 	}
365 	/* must have timed out, then... */
366 	gossip_debug(GOSSIP_WAIT_DEBUG,
367 		     "%s: operation timed out, tag %llu, %p, %d)\n",
368 		     __func__,
369 		     llu(op->tag),
370 		     op,
371 		     op->attempts);
372 	return -ETIMEDOUT;
373 }
374