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-rw-r--r--fs/fscache/object.c1106
1 files changed, 570 insertions, 536 deletions
diff --git a/fs/fscache/object.c b/fs/fscache/object.c
index 50d41c180211..86d75a60b20c 100644
--- a/fs/fscache/object.c
+++ b/fs/fscache/object.c
@@ -15,52 +15,131 @@
15#define FSCACHE_DEBUG_LEVEL COOKIE 15#define FSCACHE_DEBUG_LEVEL COOKIE
16#include <linux/module.h> 16#include <linux/module.h>
17#include <linux/slab.h> 17#include <linux/slab.h>
18#include <linux/prefetch.h>
18#include "internal.h" 19#include "internal.h"
19 20
20const char *fscache_object_states[FSCACHE_OBJECT__NSTATES] = { 21static const struct fscache_state *fscache_abort_initialisation(struct fscache_object *, int);
21 [FSCACHE_OBJECT_INIT] = "OBJECT_INIT", 22static const struct fscache_state *fscache_kill_dependents(struct fscache_object *, int);
22 [FSCACHE_OBJECT_LOOKING_UP] = "OBJECT_LOOKING_UP", 23static const struct fscache_state *fscache_drop_object(struct fscache_object *, int);
23 [FSCACHE_OBJECT_CREATING] = "OBJECT_CREATING", 24static const struct fscache_state *fscache_initialise_object(struct fscache_object *, int);
24 [FSCACHE_OBJECT_AVAILABLE] = "OBJECT_AVAILABLE", 25static const struct fscache_state *fscache_invalidate_object(struct fscache_object *, int);
25 [FSCACHE_OBJECT_ACTIVE] = "OBJECT_ACTIVE", 26static const struct fscache_state *fscache_jumpstart_dependents(struct fscache_object *, int);
26 [FSCACHE_OBJECT_INVALIDATING] = "OBJECT_INVALIDATING", 27static const struct fscache_state *fscache_kill_object(struct fscache_object *, int);
27 [FSCACHE_OBJECT_UPDATING] = "OBJECT_UPDATING", 28static const struct fscache_state *fscache_lookup_failure(struct fscache_object *, int);
28 [FSCACHE_OBJECT_DYING] = "OBJECT_DYING", 29static const struct fscache_state *fscache_look_up_object(struct fscache_object *, int);
29 [FSCACHE_OBJECT_LC_DYING] = "OBJECT_LC_DYING", 30static const struct fscache_state *fscache_object_available(struct fscache_object *, int);
30 [FSCACHE_OBJECT_ABORT_INIT] = "OBJECT_ABORT_INIT", 31static const struct fscache_state *fscache_parent_ready(struct fscache_object *, int);
31 [FSCACHE_OBJECT_RELEASING] = "OBJECT_RELEASING", 32static const struct fscache_state *fscache_update_object(struct fscache_object *, int);
32 [FSCACHE_OBJECT_RECYCLING] = "OBJECT_RECYCLING", 33
33 [FSCACHE_OBJECT_WITHDRAWING] = "OBJECT_WITHDRAWING", 34#define __STATE_NAME(n) fscache_osm_##n
34 [FSCACHE_OBJECT_DEAD] = "OBJECT_DEAD", 35#define STATE(n) (&__STATE_NAME(n))
36
37/*
38 * Define a work state. Work states are execution states. No event processing
39 * is performed by them. The function attached to a work state returns a
40 * pointer indicating the next state to which the state machine should
41 * transition. Returning NO_TRANSIT repeats the current state, but goes back
42 * to the scheduler first.
43 */
44#define WORK_STATE(n, sn, f) \
45 const struct fscache_state __STATE_NAME(n) = { \
46 .name = #n, \
47 .short_name = sn, \
48 .work = f \
49 }
50
51/*
52 * Returns from work states.
53 */
54#define transit_to(state) ({ prefetch(&STATE(state)->work); STATE(state); })
55
56#define NO_TRANSIT ((struct fscache_state *)NULL)
57
58/*
59 * Define a wait state. Wait states are event processing states. No execution
60 * is performed by them. Wait states are just tables of "if event X occurs,
61 * clear it and transition to state Y". The dispatcher returns to the
62 * scheduler if none of the events in which the wait state has an interest are
63 * currently pending.
64 */
65#define WAIT_STATE(n, sn, ...) \
66 const struct fscache_state __STATE_NAME(n) = { \
67 .name = #n, \
68 .short_name = sn, \
69 .work = NULL, \
70 .transitions = { __VA_ARGS__, { 0, NULL } } \
71 }
72
73#define TRANSIT_TO(state, emask) \
74 { .events = (emask), .transit_to = STATE(state) }
75
76/*
77 * The object state machine.
78 */
79static WORK_STATE(INIT_OBJECT, "INIT", fscache_initialise_object);
80static WORK_STATE(PARENT_READY, "PRDY", fscache_parent_ready);
81static WORK_STATE(ABORT_INIT, "ABRT", fscache_abort_initialisation);
82static WORK_STATE(LOOK_UP_OBJECT, "LOOK", fscache_look_up_object);
83static WORK_STATE(CREATE_OBJECT, "CRTO", fscache_look_up_object);
84static WORK_STATE(OBJECT_AVAILABLE, "AVBL", fscache_object_available);
85static WORK_STATE(JUMPSTART_DEPS, "JUMP", fscache_jumpstart_dependents);
86
87static WORK_STATE(INVALIDATE_OBJECT, "INVL", fscache_invalidate_object);
88static WORK_STATE(UPDATE_OBJECT, "UPDT", fscache_update_object);
89
90static WORK_STATE(LOOKUP_FAILURE, "LCFL", fscache_lookup_failure);
91static WORK_STATE(KILL_OBJECT, "KILL", fscache_kill_object);
92static WORK_STATE(KILL_DEPENDENTS, "KDEP", fscache_kill_dependents);
93static WORK_STATE(DROP_OBJECT, "DROP", fscache_drop_object);
94static WORK_STATE(OBJECT_DEAD, "DEAD", (void*)2UL);
95
96static WAIT_STATE(WAIT_FOR_INIT, "?INI",
97 TRANSIT_TO(INIT_OBJECT, 1 << FSCACHE_OBJECT_EV_NEW_CHILD));
98
99static WAIT_STATE(WAIT_FOR_PARENT, "?PRN",
100 TRANSIT_TO(PARENT_READY, 1 << FSCACHE_OBJECT_EV_PARENT_READY));
101
102static WAIT_STATE(WAIT_FOR_CMD, "?CMD",
103 TRANSIT_TO(INVALIDATE_OBJECT, 1 << FSCACHE_OBJECT_EV_INVALIDATE),
104 TRANSIT_TO(UPDATE_OBJECT, 1 << FSCACHE_OBJECT_EV_UPDATE),
105 TRANSIT_TO(JUMPSTART_DEPS, 1 << FSCACHE_OBJECT_EV_NEW_CHILD));
106
107static WAIT_STATE(WAIT_FOR_CLEARANCE, "?CLR",
108 TRANSIT_TO(KILL_OBJECT, 1 << FSCACHE_OBJECT_EV_CLEARED));
109
110/*
111 * Out-of-band event transition tables. These are for handling unexpected
112 * events, such as an I/O error. If an OOB event occurs, the state machine
113 * clears and disables the event and forces a transition to the nominated work
114 * state (acurrently executing work states will complete first).
115 *
116 * In such a situation, object->state remembers the state the machine should
117 * have been in/gone to and returning NO_TRANSIT returns to that.
118 */
119static const struct fscache_transition fscache_osm_init_oob[] = {
120 TRANSIT_TO(ABORT_INIT,
121 (1 << FSCACHE_OBJECT_EV_ERROR) |
122 (1 << FSCACHE_OBJECT_EV_KILL)),
123 { 0, NULL }
124};
125
126static const struct fscache_transition fscache_osm_lookup_oob[] = {
127 TRANSIT_TO(LOOKUP_FAILURE,
128 (1 << FSCACHE_OBJECT_EV_ERROR) |
129 (1 << FSCACHE_OBJECT_EV_KILL)),
130 { 0, NULL }
35}; 131};
36EXPORT_SYMBOL(fscache_object_states); 132
37 133static const struct fscache_transition fscache_osm_run_oob[] = {
38const char fscache_object_states_short[FSCACHE_OBJECT__NSTATES][5] = { 134 TRANSIT_TO(KILL_OBJECT,
39 [FSCACHE_OBJECT_INIT] = "INIT", 135 (1 << FSCACHE_OBJECT_EV_ERROR) |
40 [FSCACHE_OBJECT_LOOKING_UP] = "LOOK", 136 (1 << FSCACHE_OBJECT_EV_KILL)),
41 [FSCACHE_OBJECT_CREATING] = "CRTN", 137 { 0, NULL }
42 [FSCACHE_OBJECT_AVAILABLE] = "AVBL",
43 [FSCACHE_OBJECT_ACTIVE] = "ACTV",
44 [FSCACHE_OBJECT_INVALIDATING] = "INVL",
45 [FSCACHE_OBJECT_UPDATING] = "UPDT",
46 [FSCACHE_OBJECT_DYING] = "DYNG",
47 [FSCACHE_OBJECT_LC_DYING] = "LCDY",
48 [FSCACHE_OBJECT_ABORT_INIT] = "ABTI",
49 [FSCACHE_OBJECT_RELEASING] = "RELS",
50 [FSCACHE_OBJECT_RECYCLING] = "RCYC",
51 [FSCACHE_OBJECT_WITHDRAWING] = "WTHD",
52 [FSCACHE_OBJECT_DEAD] = "DEAD",
53}; 138};
54 139
55static int fscache_get_object(struct fscache_object *); 140static int fscache_get_object(struct fscache_object *);
56static void fscache_put_object(struct fscache_object *); 141static void fscache_put_object(struct fscache_object *);
57static void fscache_initialise_object(struct fscache_object *); 142static bool fscache_enqueue_dependents(struct fscache_object *, int);
58static void fscache_lookup_object(struct fscache_object *);
59static void fscache_object_available(struct fscache_object *);
60static void fscache_invalidate_object(struct fscache_object *);
61static void fscache_release_object(struct fscache_object *);
62static void fscache_withdraw_object(struct fscache_object *);
63static void fscache_enqueue_dependents(struct fscache_object *);
64static void fscache_dequeue_object(struct fscache_object *); 143static void fscache_dequeue_object(struct fscache_object *);
65 144
66/* 145/*
@@ -75,295 +154,116 @@ static inline void fscache_done_parent_op(struct fscache_object *object)
75 object->debug_id, parent->debug_id, parent->n_ops); 154 object->debug_id, parent->debug_id, parent->n_ops);
76 155
77 spin_lock_nested(&parent->lock, 1); 156 spin_lock_nested(&parent->lock, 1);
78 parent->n_ops--;
79 parent->n_obj_ops--; 157 parent->n_obj_ops--;
158 parent->n_ops--;
80 if (parent->n_ops == 0) 159 if (parent->n_ops == 0)
81 fscache_raise_event(parent, FSCACHE_OBJECT_EV_CLEARED); 160 fscache_raise_event(parent, FSCACHE_OBJECT_EV_CLEARED);
82 spin_unlock(&parent->lock); 161 spin_unlock(&parent->lock);
83} 162}
84 163
85/* 164/*
86 * Notify netfs of invalidation completion. 165 * Object state machine dispatcher.
87 */ 166 */
88static inline void fscache_invalidation_complete(struct fscache_cookie *cookie) 167static void fscache_object_sm_dispatcher(struct fscache_object *object)
89{ 168{
90 if (test_and_clear_bit(FSCACHE_COOKIE_INVALIDATING, &cookie->flags)) 169 const struct fscache_transition *t;
91 wake_up_bit(&cookie->flags, FSCACHE_COOKIE_INVALIDATING); 170 const struct fscache_state *state, *new_state;
92} 171 unsigned long events, event_mask;
93 172 int event = -1;
94/*
95 * process events that have been sent to an object's state machine
96 * - initiates parent lookup
97 * - does object lookup
98 * - does object creation
99 * - does object recycling and retirement
100 * - does object withdrawal
101 */
102static void fscache_object_state_machine(struct fscache_object *object)
103{
104 enum fscache_object_state new_state;
105 struct fscache_cookie *cookie;
106 int event;
107 173
108 ASSERT(object != NULL); 174 ASSERT(object != NULL);
109 175
110 _enter("{OBJ%x,%s,%lx}", 176 _enter("{OBJ%x,%s,%lx}",
111 object->debug_id, fscache_object_states[object->state], 177 object->debug_id, object->state->name, object->events);
112 object->events); 178
113 179 event_mask = object->event_mask;
114 switch (object->state) { 180restart:
115 /* wait for the parent object to become ready */ 181 object->event_mask = 0; /* Mask normal event handling */
116 case FSCACHE_OBJECT_INIT: 182 state = object->state;
117 object->event_mask = 183restart_masked:
118 FSCACHE_OBJECT_EVENTS_MASK & 184 events = object->events;
119 ~(1 << FSCACHE_OBJECT_EV_CLEARED); 185
120 fscache_initialise_object(object); 186 /* Handle any out-of-band events (typically an error) */
121 goto done; 187 if (events & object->oob_event_mask) {
122 188 _debug("{OBJ%x} oob %lx",
123 /* look up the object metadata on disk */ 189 object->debug_id, events & object->oob_event_mask);
124 case FSCACHE_OBJECT_LOOKING_UP: 190 for (t = object->oob_table; t->events; t++) {
125 fscache_lookup_object(object); 191 if (events & t->events) {
126 goto lookup_transit; 192 state = t->transit_to;
127 193 ASSERT(state->work != NULL);
128 /* create the object metadata on disk */ 194 event = fls(events & t->events) - 1;
129 case FSCACHE_OBJECT_CREATING: 195 __clear_bit(event, &object->oob_event_mask);
130 fscache_lookup_object(object); 196 clear_bit(event, &object->events);
131 goto lookup_transit; 197 goto execute_work_state;
132 198 }
133 /* handle an object becoming available; start pending
134 * operations and queue dependent operations for processing */
135 case FSCACHE_OBJECT_AVAILABLE:
136 fscache_object_available(object);
137 goto active_transit;
138
139 /* normal running state */
140 case FSCACHE_OBJECT_ACTIVE:
141 goto active_transit;
142
143 /* Invalidate an object on disk */
144 case FSCACHE_OBJECT_INVALIDATING:
145 clear_bit(FSCACHE_OBJECT_EV_INVALIDATE, &object->events);
146 fscache_stat(&fscache_n_invalidates_run);
147 fscache_stat(&fscache_n_cop_invalidate_object);
148 fscache_invalidate_object(object);
149 fscache_stat_d(&fscache_n_cop_invalidate_object);
150 fscache_raise_event(object, FSCACHE_OBJECT_EV_UPDATE);
151 goto active_transit;
152
153 /* update the object metadata on disk */
154 case FSCACHE_OBJECT_UPDATING:
155 clear_bit(FSCACHE_OBJECT_EV_UPDATE, &object->events);
156 fscache_stat(&fscache_n_updates_run);
157 fscache_stat(&fscache_n_cop_update_object);
158 object->cache->ops->update_object(object);
159 fscache_stat_d(&fscache_n_cop_update_object);
160 goto active_transit;
161
162 /* handle an object dying during lookup or creation */
163 case FSCACHE_OBJECT_LC_DYING:
164 object->event_mask &= ~(1 << FSCACHE_OBJECT_EV_UPDATE);
165 fscache_stat(&fscache_n_cop_lookup_complete);
166 object->cache->ops->lookup_complete(object);
167 fscache_stat_d(&fscache_n_cop_lookup_complete);
168
169 spin_lock(&object->lock);
170 object->state = FSCACHE_OBJECT_DYING;
171 cookie = object->cookie;
172 if (cookie) {
173 if (test_and_clear_bit(FSCACHE_COOKIE_LOOKING_UP,
174 &cookie->flags))
175 wake_up_bit(&cookie->flags,
176 FSCACHE_COOKIE_LOOKING_UP);
177 if (test_and_clear_bit(FSCACHE_COOKIE_CREATING,
178 &cookie->flags))
179 wake_up_bit(&cookie->flags,
180 FSCACHE_COOKIE_CREATING);
181 } 199 }
182 spin_unlock(&object->lock); 200 }
183 201
184 fscache_done_parent_op(object); 202 /* Wait states are just transition tables */
203 if (!state->work) {
204 if (events & event_mask) {
205 for (t = state->transitions; t->events; t++) {
206 if (events & t->events) {
207 new_state = t->transit_to;
208 event = fls(events & t->events) - 1;
209 clear_bit(event, &object->events);
210 _debug("{OBJ%x} ev %d: %s -> %s",
211 object->debug_id, event,
212 state->name, new_state->name);
213 object->state = state = new_state;
214 goto execute_work_state;
215 }
216 }
185 217
186 /* wait for completion of all active operations on this object 218 /* The event mask didn't include all the tabled bits */
187 * and the death of all child objects of this object */ 219 BUG();
188 case FSCACHE_OBJECT_DYING:
189 dying:
190 clear_bit(FSCACHE_OBJECT_EV_CLEARED, &object->events);
191 spin_lock(&object->lock);
192 _debug("dying OBJ%x {%d,%d}",
193 object->debug_id, object->n_ops, object->n_children);
194 if (object->n_ops == 0 && object->n_children == 0) {
195 object->event_mask &=
196 ~(1 << FSCACHE_OBJECT_EV_CLEARED);
197 object->event_mask |=
198 (1 << FSCACHE_OBJECT_EV_WITHDRAW) |
199 (1 << FSCACHE_OBJECT_EV_RETIRE) |
200 (1 << FSCACHE_OBJECT_EV_RELEASE) |
201 (1 << FSCACHE_OBJECT_EV_ERROR);
202 } else {
203 object->event_mask &=
204 ~((1 << FSCACHE_OBJECT_EV_WITHDRAW) |
205 (1 << FSCACHE_OBJECT_EV_RETIRE) |
206 (1 << FSCACHE_OBJECT_EV_RELEASE) |
207 (1 << FSCACHE_OBJECT_EV_ERROR));
208 object->event_mask |=
209 1 << FSCACHE_OBJECT_EV_CLEARED;
210 } 220 }
211 spin_unlock(&object->lock); 221 /* Randomly woke up */
212 fscache_enqueue_dependents(object); 222 goto unmask_events;
213 fscache_start_operations(object);
214 goto terminal_transit;
215
216 /* handle an abort during initialisation */
217 case FSCACHE_OBJECT_ABORT_INIT:
218 _debug("handle abort init %lx", object->events);
219 object->event_mask &= ~(1 << FSCACHE_OBJECT_EV_UPDATE);
220
221 spin_lock(&object->lock);
222 fscache_dequeue_object(object);
223
224 object->state = FSCACHE_OBJECT_DYING;
225 if (test_and_clear_bit(FSCACHE_COOKIE_CREATING,
226 &object->cookie->flags))
227 wake_up_bit(&object->cookie->flags,
228 FSCACHE_COOKIE_CREATING);
229 spin_unlock(&object->lock);
230 goto dying;
231
232 /* handle the netfs releasing an object and possibly marking it
233 * obsolete too */
234 case FSCACHE_OBJECT_RELEASING:
235 case FSCACHE_OBJECT_RECYCLING:
236 object->event_mask &=
237 ~((1 << FSCACHE_OBJECT_EV_WITHDRAW) |
238 (1 << FSCACHE_OBJECT_EV_RETIRE) |
239 (1 << FSCACHE_OBJECT_EV_RELEASE) |
240 (1 << FSCACHE_OBJECT_EV_ERROR));
241 fscache_release_object(object);
242 spin_lock(&object->lock);
243 object->state = FSCACHE_OBJECT_DEAD;
244 spin_unlock(&object->lock);
245 fscache_stat(&fscache_n_object_dead);
246 goto terminal_transit;
247
248 /* handle the parent cache of this object being withdrawn from
249 * active service */
250 case FSCACHE_OBJECT_WITHDRAWING:
251 object->event_mask &=
252 ~((1 << FSCACHE_OBJECT_EV_WITHDRAW) |
253 (1 << FSCACHE_OBJECT_EV_RETIRE) |
254 (1 << FSCACHE_OBJECT_EV_RELEASE) |
255 (1 << FSCACHE_OBJECT_EV_ERROR));
256 fscache_withdraw_object(object);
257 spin_lock(&object->lock);
258 object->state = FSCACHE_OBJECT_DEAD;
259 spin_unlock(&object->lock);
260 fscache_stat(&fscache_n_object_dead);
261 goto terminal_transit;
262
263 /* complain about the object being woken up once it is
264 * deceased */
265 case FSCACHE_OBJECT_DEAD:
266 printk(KERN_ERR "FS-Cache:"
267 " Unexpected event in dead state %lx\n",
268 object->events & object->event_mask);
269 BUG();
270
271 default:
272 printk(KERN_ERR "FS-Cache: Unknown object state %u\n",
273 object->state);
274 BUG();
275 }
276
277 /* determine the transition from a lookup state */
278lookup_transit:
279 event = fls(object->events & object->event_mask) - 1;
280 switch (event) {
281 case FSCACHE_OBJECT_EV_WITHDRAW:
282 case FSCACHE_OBJECT_EV_RETIRE:
283 case FSCACHE_OBJECT_EV_RELEASE:
284 case FSCACHE_OBJECT_EV_ERROR:
285 new_state = FSCACHE_OBJECT_LC_DYING;
286 goto change_state;
287 case FSCACHE_OBJECT_EV_INVALIDATE:
288 new_state = FSCACHE_OBJECT_INVALIDATING;
289 goto change_state;
290 case FSCACHE_OBJECT_EV_REQUEUE:
291 goto done;
292 case -1:
293 goto done; /* sleep until event */
294 default:
295 goto unsupported_event;
296 } 223 }
297 224
298 /* determine the transition from an active state */ 225execute_work_state:
299active_transit: 226 _debug("{OBJ%x} exec %s", object->debug_id, state->name);
300 event = fls(object->events & object->event_mask) - 1;
301 switch (event) {
302 case FSCACHE_OBJECT_EV_WITHDRAW:
303 case FSCACHE_OBJECT_EV_RETIRE:
304 case FSCACHE_OBJECT_EV_RELEASE:
305 case FSCACHE_OBJECT_EV_ERROR:
306 new_state = FSCACHE_OBJECT_DYING;
307 goto change_state;
308 case FSCACHE_OBJECT_EV_INVALIDATE:
309 new_state = FSCACHE_OBJECT_INVALIDATING;
310 goto change_state;
311 case FSCACHE_OBJECT_EV_UPDATE:
312 new_state = FSCACHE_OBJECT_UPDATING;
313 goto change_state;
314 case -1:
315 new_state = FSCACHE_OBJECT_ACTIVE;
316 goto change_state; /* sleep until event */
317 default:
318 goto unsupported_event;
319 }
320 227
321 /* determine the transition from a terminal state */ 228 new_state = state->work(object, event);
322terminal_transit: 229 event = -1;
323 event = fls(object->events & object->event_mask) - 1; 230 if (new_state == NO_TRANSIT) {
324 switch (event) { 231 _debug("{OBJ%x} %s notrans", object->debug_id, state->name);
325 case FSCACHE_OBJECT_EV_WITHDRAW: 232 fscache_enqueue_object(object);
326 new_state = FSCACHE_OBJECT_WITHDRAWING; 233 event_mask = object->oob_event_mask;
327 goto change_state; 234 goto unmask_events;
328 case FSCACHE_OBJECT_EV_RETIRE:
329 new_state = FSCACHE_OBJECT_RECYCLING;
330 goto change_state;
331 case FSCACHE_OBJECT_EV_RELEASE:
332 new_state = FSCACHE_OBJECT_RELEASING;
333 goto change_state;
334 case FSCACHE_OBJECT_EV_ERROR:
335 new_state = FSCACHE_OBJECT_WITHDRAWING;
336 goto change_state;
337 case FSCACHE_OBJECT_EV_CLEARED:
338 new_state = FSCACHE_OBJECT_DYING;
339 goto change_state;
340 case -1:
341 goto done; /* sleep until event */
342 default:
343 goto unsupported_event;
344 } 235 }
345 236
346change_state: 237 _debug("{OBJ%x} %s -> %s",
347 spin_lock(&object->lock); 238 object->debug_id, state->name, new_state->name);
348 object->state = new_state; 239 object->state = state = new_state;
349 spin_unlock(&object->lock);
350 240
351done: 241 if (state->work) {
352 _leave(" [->%s]", fscache_object_states[object->state]); 242 if (unlikely(state->work == ((void *)2UL))) {
353 return; 243 _leave(" [dead]");
244 return;
245 }
246 goto restart_masked;
247 }
354 248
355unsupported_event: 249 /* Transited to wait state */
356 printk(KERN_ERR "FS-Cache:" 250 event_mask = object->oob_event_mask;
357 " Unsupported event %d [%lx/%lx] in state %s\n", 251 for (t = state->transitions; t->events; t++)
358 event, object->events, object->event_mask, 252 event_mask |= t->events;
359 fscache_object_states[object->state]); 253
360 BUG(); 254unmask_events:
255 object->event_mask = event_mask;
256 smp_mb();
257 events = object->events;
258 if (events & event_mask)
259 goto restart;
260 _leave(" [msk %lx]", event_mask);
361} 261}
362 262
363/* 263/*
364 * execute an object 264 * execute an object
365 */ 265 */
366void fscache_object_work_func(struct work_struct *work) 266static void fscache_object_work_func(struct work_struct *work)
367{ 267{
368 struct fscache_object *object = 268 struct fscache_object *object =
369 container_of(work, struct fscache_object, work); 269 container_of(work, struct fscache_object, work);
@@ -372,14 +272,70 @@ void fscache_object_work_func(struct work_struct *work)
372 _enter("{OBJ%x}", object->debug_id); 272 _enter("{OBJ%x}", object->debug_id);
373 273
374 start = jiffies; 274 start = jiffies;
375 fscache_object_state_machine(object); 275 fscache_object_sm_dispatcher(object);
376 fscache_hist(fscache_objs_histogram, start); 276 fscache_hist(fscache_objs_histogram, start);
377 if (object->events & object->event_mask)
378 fscache_enqueue_object(object);
379 clear_bit(FSCACHE_OBJECT_EV_REQUEUE, &object->events);
380 fscache_put_object(object); 277 fscache_put_object(object);
381} 278}
382EXPORT_SYMBOL(fscache_object_work_func); 279
280/**
281 * fscache_object_init - Initialise a cache object description
282 * @object: Object description
283 * @cookie: Cookie object will be attached to
284 * @cache: Cache in which backing object will be found
285 *
286 * Initialise a cache object description to its basic values.
287 *
288 * See Documentation/filesystems/caching/backend-api.txt for a complete
289 * description.
290 */
291void fscache_object_init(struct fscache_object *object,
292 struct fscache_cookie *cookie,
293 struct fscache_cache *cache)
294{
295 const struct fscache_transition *t;
296
297 atomic_inc(&cache->object_count);
298
299 object->state = STATE(WAIT_FOR_INIT);
300 object->oob_table = fscache_osm_init_oob;
301 object->flags = 1 << FSCACHE_OBJECT_IS_LIVE;
302 spin_lock_init(&object->lock);
303 INIT_LIST_HEAD(&object->cache_link);
304 INIT_HLIST_NODE(&object->cookie_link);
305 INIT_WORK(&object->work, fscache_object_work_func);
306 INIT_LIST_HEAD(&object->dependents);
307 INIT_LIST_HEAD(&object->dep_link);
308 INIT_LIST_HEAD(&object->pending_ops);
309 object->n_children = 0;
310 object->n_ops = object->n_in_progress = object->n_exclusive = 0;
311 object->events = 0;
312 object->store_limit = 0;
313 object->store_limit_l = 0;
314 object->cache = cache;
315 object->cookie = cookie;
316 object->parent = NULL;
317
318 object->oob_event_mask = 0;
319 for (t = object->oob_table; t->events; t++)
320 object->oob_event_mask |= t->events;
321 object->event_mask = object->oob_event_mask;
322 for (t = object->state->transitions; t->events; t++)
323 object->event_mask |= t->events;
324}
325EXPORT_SYMBOL(fscache_object_init);
326
327/*
328 * Abort object initialisation before we start it.
329 */
330static const struct fscache_state *fscache_abort_initialisation(struct fscache_object *object,
331 int event)
332{
333 _enter("{OBJ%x},%d", object->debug_id, event);
334
335 object->oob_event_mask = 0;
336 fscache_dequeue_object(object);
337 return transit_to(KILL_OBJECT);
338}
383 339
384/* 340/*
385 * initialise an object 341 * initialise an object
@@ -387,130 +343,136 @@ EXPORT_SYMBOL(fscache_object_work_func);
387 * immediately to do a creation 343 * immediately to do a creation
388 * - we may need to start the process of creating a parent and we need to wait 344 * - we may need to start the process of creating a parent and we need to wait
389 * for the parent's lookup and creation to complete if it's not there yet 345 * for the parent's lookup and creation to complete if it's not there yet
390 * - an object's cookie is pinned until we clear FSCACHE_COOKIE_CREATING on the
391 * leaf-most cookies of the object and all its children
392 */ 346 */
393static void fscache_initialise_object(struct fscache_object *object) 347static const struct fscache_state *fscache_initialise_object(struct fscache_object *object,
348 int event)
394{ 349{
395 struct fscache_object *parent; 350 struct fscache_object *parent;
351 bool success;
396 352
397 _enter(""); 353 _enter("{OBJ%x},%d", object->debug_id, event);
398 ASSERT(object->cookie != NULL);
399 ASSERT(object->cookie->parent != NULL);
400
401 if (object->events & ((1 << FSCACHE_OBJECT_EV_ERROR) |
402 (1 << FSCACHE_OBJECT_EV_RELEASE) |
403 (1 << FSCACHE_OBJECT_EV_RETIRE) |
404 (1 << FSCACHE_OBJECT_EV_WITHDRAW))) {
405 _debug("abort init %lx", object->events);
406 spin_lock(&object->lock);
407 object->state = FSCACHE_OBJECT_ABORT_INIT;
408 spin_unlock(&object->lock);
409 return;
410 }
411 354
412 spin_lock(&object->cookie->lock); 355 ASSERT(list_empty(&object->dep_link));
413 spin_lock_nested(&object->cookie->parent->lock, 1);
414 356
415 parent = object->parent; 357 parent = object->parent;
416 if (!parent) { 358 if (!parent) {
417 _debug("no parent"); 359 _leave(" [no parent]");
418 set_bit(FSCACHE_OBJECT_EV_WITHDRAW, &object->events); 360 return transit_to(DROP_OBJECT);
419 } else { 361 }
420 spin_lock(&object->lock);
421 spin_lock_nested(&parent->lock, 1);
422 _debug("parent %s", fscache_object_states[parent->state]);
423
424 if (parent->state >= FSCACHE_OBJECT_DYING) {
425 _debug("bad parent");
426 set_bit(FSCACHE_OBJECT_EV_WITHDRAW, &object->events);
427 } else if (parent->state < FSCACHE_OBJECT_AVAILABLE) {
428 _debug("wait");
429
430 /* we may get woken up in this state by child objects
431 * binding on to us, so we need to make sure we don't
432 * add ourself to the list multiple times */
433 if (list_empty(&object->dep_link)) {
434 fscache_stat(&fscache_n_cop_grab_object);
435 object->cache->ops->grab_object(object);
436 fscache_stat_d(&fscache_n_cop_grab_object);
437 list_add(&object->dep_link,
438 &parent->dependents);
439
440 /* fscache_acquire_non_index_cookie() uses this
441 * to wake the chain up */
442 if (parent->state == FSCACHE_OBJECT_INIT)
443 fscache_enqueue_object(parent);
444 }
445 } else {
446 _debug("go");
447 parent->n_ops++;
448 parent->n_obj_ops++;
449 object->lookup_jif = jiffies;
450 object->state = FSCACHE_OBJECT_LOOKING_UP;
451 set_bit(FSCACHE_OBJECT_EV_REQUEUE, &object->events);
452 }
453 362
454 spin_unlock(&parent->lock); 363 _debug("parent: %s of:%lx", parent->state->name, parent->flags);
455 spin_unlock(&object->lock); 364
365 if (fscache_object_is_dying(parent)) {
366 _leave(" [bad parent]");
367 return transit_to(DROP_OBJECT);
456 } 368 }
457 369
458 spin_unlock(&object->cookie->parent->lock); 370 if (fscache_object_is_available(parent)) {
459 spin_unlock(&object->cookie->lock); 371 _leave(" [ready]");
372 return transit_to(PARENT_READY);
373 }
374
375 _debug("wait");
376
377 spin_lock(&parent->lock);
378 fscache_stat(&fscache_n_cop_grab_object);
379 success = false;
380 if (fscache_object_is_live(parent) &&
381 object->cache->ops->grab_object(object)) {
382 list_add(&object->dep_link, &parent->dependents);
383 success = true;
384 }
385 fscache_stat_d(&fscache_n_cop_grab_object);
386 spin_unlock(&parent->lock);
387 if (!success) {
388 _leave(" [grab failed]");
389 return transit_to(DROP_OBJECT);
390 }
391
392 /* fscache_acquire_non_index_cookie() uses this
393 * to wake the chain up */
394 fscache_raise_event(parent, FSCACHE_OBJECT_EV_NEW_CHILD);
395 _leave(" [wait]");
396 return transit_to(WAIT_FOR_PARENT);
397}
398
399/*
400 * Once the parent object is ready, we should kick off our lookup op.
401 */
402static const struct fscache_state *fscache_parent_ready(struct fscache_object *object,
403 int event)
404{
405 struct fscache_object *parent = object->parent;
406
407 _enter("{OBJ%x},%d", object->debug_id, event);
408
409 ASSERT(parent != NULL);
410
411 spin_lock(&parent->lock);
412 parent->n_ops++;
413 parent->n_obj_ops++;
414 object->lookup_jif = jiffies;
415 spin_unlock(&parent->lock);
416
460 _leave(""); 417 _leave("");
418 return transit_to(LOOK_UP_OBJECT);
461} 419}
462 420
463/* 421/*
464 * look an object up in the cache from which it was allocated 422 * look an object up in the cache from which it was allocated
465 * - we hold an "access lock" on the parent object, so the parent object cannot 423 * - we hold an "access lock" on the parent object, so the parent object cannot
466 * be withdrawn by either party till we've finished 424 * be withdrawn by either party till we've finished
467 * - an object's cookie is pinned until we clear FSCACHE_COOKIE_CREATING on the
468 * leaf-most cookies of the object and all its children
469 */ 425 */
470static void fscache_lookup_object(struct fscache_object *object) 426static const struct fscache_state *fscache_look_up_object(struct fscache_object *object,
427 int event)
471{ 428{
472 struct fscache_cookie *cookie = object->cookie; 429 struct fscache_cookie *cookie = object->cookie;
473 struct fscache_object *parent; 430 struct fscache_object *parent = object->parent;
474 int ret; 431 int ret;
475 432
476 _enter(""); 433 _enter("{OBJ%x},%d", object->debug_id, event);
434
435 object->oob_table = fscache_osm_lookup_oob;
477 436
478 parent = object->parent;
479 ASSERT(parent != NULL); 437 ASSERT(parent != NULL);
480 ASSERTCMP(parent->n_ops, >, 0); 438 ASSERTCMP(parent->n_ops, >, 0);
481 ASSERTCMP(parent->n_obj_ops, >, 0); 439 ASSERTCMP(parent->n_obj_ops, >, 0);
482 440
483 /* make sure the parent is still available */ 441 /* make sure the parent is still available */
484 ASSERTCMP(parent->state, >=, FSCACHE_OBJECT_AVAILABLE); 442 ASSERT(fscache_object_is_available(parent));
485 443
486 if (parent->state >= FSCACHE_OBJECT_DYING || 444 if (fscache_object_is_dying(parent) ||
487 test_bit(FSCACHE_IOERROR, &object->cache->flags)) { 445 test_bit(FSCACHE_IOERROR, &object->cache->flags) ||
488 _debug("unavailable"); 446 !fscache_use_cookie(object)) {
489 set_bit(FSCACHE_OBJECT_EV_WITHDRAW, &object->events); 447 _leave(" [unavailable]");
490 _leave(""); 448 return transit_to(LOOKUP_FAILURE);
491 return;
492 } 449 }
493 450
494 _debug("LOOKUP \"%s/%s\" in \"%s\"", 451 _debug("LOOKUP \"%s\" in \"%s\"",
495 parent->cookie->def->name, cookie->def->name, 452 cookie->def->name, object->cache->tag->name);
496 object->cache->tag->name);
497 453
498 fscache_stat(&fscache_n_object_lookups); 454 fscache_stat(&fscache_n_object_lookups);
499 fscache_stat(&fscache_n_cop_lookup_object); 455 fscache_stat(&fscache_n_cop_lookup_object);
500 ret = object->cache->ops->lookup_object(object); 456 ret = object->cache->ops->lookup_object(object);
501 fscache_stat_d(&fscache_n_cop_lookup_object); 457 fscache_stat_d(&fscache_n_cop_lookup_object);
502 458
503 if (test_bit(FSCACHE_OBJECT_EV_ERROR, &object->events)) 459 fscache_unuse_cookie(object);
504 set_bit(FSCACHE_COOKIE_UNAVAILABLE, &cookie->flags);
505 460
506 if (ret == -ETIMEDOUT) { 461 if (ret == -ETIMEDOUT) {
507 /* probably stuck behind another object, so move this one to 462 /* probably stuck behind another object, so move this one to
508 * the back of the queue */ 463 * the back of the queue */
509 fscache_stat(&fscache_n_object_lookups_timed_out); 464 fscache_stat(&fscache_n_object_lookups_timed_out);
510 set_bit(FSCACHE_OBJECT_EV_REQUEUE, &object->events); 465 _leave(" [timeout]");
466 return NO_TRANSIT;
511 } 467 }
512 468
513 _leave(""); 469 if (ret < 0) {
470 _leave(" [error]");
471 return transit_to(LOOKUP_FAILURE);
472 }
473
474 _leave(" [ok]");
475 return transit_to(OBJECT_AVAILABLE);
514} 476}
515 477
516/** 478/**
@@ -524,32 +486,20 @@ void fscache_object_lookup_negative(struct fscache_object *object)
524{ 486{
525 struct fscache_cookie *cookie = object->cookie; 487 struct fscache_cookie *cookie = object->cookie;
526 488
527 _enter("{OBJ%x,%s}", 489 _enter("{OBJ%x,%s}", object->debug_id, object->state->name);
528 object->debug_id, fscache_object_states[object->state]);
529 490
530 spin_lock(&object->lock); 491 if (!test_and_set_bit(FSCACHE_OBJECT_IS_LOOKED_UP, &object->flags)) {
531 if (object->state == FSCACHE_OBJECT_LOOKING_UP) {
532 fscache_stat(&fscache_n_object_lookups_negative); 492 fscache_stat(&fscache_n_object_lookups_negative);
533 493
534 /* transit here to allow write requests to begin stacking up 494 /* Allow write requests to begin stacking up and read requests to begin
535 * and read requests to begin returning ENODATA */ 495 * returning ENODATA.
536 object->state = FSCACHE_OBJECT_CREATING; 496 */
537 spin_unlock(&object->lock);
538
539 set_bit(FSCACHE_COOKIE_PENDING_FILL, &cookie->flags);
540 set_bit(FSCACHE_COOKIE_NO_DATA_YET, &cookie->flags); 497 set_bit(FSCACHE_COOKIE_NO_DATA_YET, &cookie->flags);
541 498
542 _debug("wake up lookup %p", &cookie->flags); 499 _debug("wake up lookup %p", &cookie->flags);
543 smp_mb__before_clear_bit(); 500 clear_bit_unlock(FSCACHE_COOKIE_LOOKING_UP, &cookie->flags);
544 clear_bit(FSCACHE_COOKIE_LOOKING_UP, &cookie->flags);
545 smp_mb__after_clear_bit();
546 wake_up_bit(&cookie->flags, FSCACHE_COOKIE_LOOKING_UP); 501 wake_up_bit(&cookie->flags, FSCACHE_COOKIE_LOOKING_UP);
547 set_bit(FSCACHE_OBJECT_EV_REQUEUE, &object->events);
548 } else {
549 ASSERTCMP(object->state, ==, FSCACHE_OBJECT_CREATING);
550 spin_unlock(&object->lock);
551 } 502 }
552
553 _leave(""); 503 _leave("");
554} 504}
555EXPORT_SYMBOL(fscache_object_lookup_negative); 505EXPORT_SYMBOL(fscache_object_lookup_negative);
@@ -568,38 +518,26 @@ void fscache_obtained_object(struct fscache_object *object)
568{ 518{
569 struct fscache_cookie *cookie = object->cookie; 519 struct fscache_cookie *cookie = object->cookie;
570 520
571 _enter("{OBJ%x,%s}", 521 _enter("{OBJ%x,%s}", object->debug_id, object->state->name);
572 object->debug_id, fscache_object_states[object->state]);
573 522
574 /* if we were still looking up, then we must have a positive lookup 523 /* if we were still looking up, then we must have a positive lookup
575 * result, in which case there may be data available */ 524 * result, in which case there may be data available */
576 spin_lock(&object->lock); 525 if (!test_and_set_bit(FSCACHE_OBJECT_IS_LOOKED_UP, &object->flags)) {
577 if (object->state == FSCACHE_OBJECT_LOOKING_UP) {
578 fscache_stat(&fscache_n_object_lookups_positive); 526 fscache_stat(&fscache_n_object_lookups_positive);
579 527
580 clear_bit(FSCACHE_COOKIE_NO_DATA_YET, &cookie->flags); 528 /* We do (presumably) have data */
529 clear_bit_unlock(FSCACHE_COOKIE_NO_DATA_YET, &cookie->flags);
581 530
582 object->state = FSCACHE_OBJECT_AVAILABLE; 531 /* Allow write requests to begin stacking up and read requests
583 spin_unlock(&object->lock); 532 * to begin shovelling data.
584 533 */
585 smp_mb__before_clear_bit(); 534 clear_bit_unlock(FSCACHE_COOKIE_LOOKING_UP, &cookie->flags);
586 clear_bit(FSCACHE_COOKIE_LOOKING_UP, &cookie->flags);
587 smp_mb__after_clear_bit();
588 wake_up_bit(&cookie->flags, FSCACHE_COOKIE_LOOKING_UP); 535 wake_up_bit(&cookie->flags, FSCACHE_COOKIE_LOOKING_UP);
589 set_bit(FSCACHE_OBJECT_EV_REQUEUE, &object->events);
590 } else { 536 } else {
591 ASSERTCMP(object->state, ==, FSCACHE_OBJECT_CREATING);
592 fscache_stat(&fscache_n_object_created); 537 fscache_stat(&fscache_n_object_created);
593
594 object->state = FSCACHE_OBJECT_AVAILABLE;
595 spin_unlock(&object->lock);
596 set_bit(FSCACHE_OBJECT_EV_REQUEUE, &object->events);
597 smp_wmb();
598 } 538 }
599 539
600 if (test_and_clear_bit(FSCACHE_COOKIE_CREATING, &cookie->flags)) 540 set_bit(FSCACHE_OBJECT_IS_AVAILABLE, &object->flags);
601 wake_up_bit(&cookie->flags, FSCACHE_COOKIE_CREATING);
602
603 _leave(""); 541 _leave("");
604} 542}
605EXPORT_SYMBOL(fscache_obtained_object); 543EXPORT_SYMBOL(fscache_obtained_object);
@@ -607,15 +545,14 @@ EXPORT_SYMBOL(fscache_obtained_object);
607/* 545/*
608 * handle an object that has just become available 546 * handle an object that has just become available
609 */ 547 */
610static void fscache_object_available(struct fscache_object *object) 548static const struct fscache_state *fscache_object_available(struct fscache_object *object,
549 int event)
611{ 550{
612 _enter("{OBJ%x}", object->debug_id); 551 _enter("{OBJ%x},%d", object->debug_id, event);
613 552
614 spin_lock(&object->lock); 553 object->oob_table = fscache_osm_run_oob;
615 554
616 if (object->cookie && 555 spin_lock(&object->lock);
617 test_and_clear_bit(FSCACHE_COOKIE_CREATING, &object->cookie->flags))
618 wake_up_bit(&object->cookie->flags, FSCACHE_COOKIE_CREATING);
619 556
620 fscache_done_parent_op(object); 557 fscache_done_parent_op(object);
621 if (object->n_in_progress == 0) { 558 if (object->n_in_progress == 0) {
@@ -631,130 +568,158 @@ static void fscache_object_available(struct fscache_object *object)
631 fscache_stat(&fscache_n_cop_lookup_complete); 568 fscache_stat(&fscache_n_cop_lookup_complete);
632 object->cache->ops->lookup_complete(object); 569 object->cache->ops->lookup_complete(object);
633 fscache_stat_d(&fscache_n_cop_lookup_complete); 570 fscache_stat_d(&fscache_n_cop_lookup_complete);
634 fscache_enqueue_dependents(object);
635 571
636 fscache_hist(fscache_obj_instantiate_histogram, object->lookup_jif); 572 fscache_hist(fscache_obj_instantiate_histogram, object->lookup_jif);
637 fscache_stat(&fscache_n_object_avail); 573 fscache_stat(&fscache_n_object_avail);
638 574
639 _leave(""); 575 _leave("");
576 return transit_to(JUMPSTART_DEPS);
640} 577}
641 578
642/* 579/*
643 * drop an object's attachments 580 * Wake up this object's dependent objects now that we've become available.
644 */ 581 */
645static void fscache_drop_object(struct fscache_object *object) 582static const struct fscache_state *fscache_jumpstart_dependents(struct fscache_object *object,
583 int event)
646{ 584{
647 struct fscache_object *parent = object->parent; 585 _enter("{OBJ%x},%d", object->debug_id, event);
648 struct fscache_cache *cache = object->cache;
649 586
650 _enter("{OBJ%x,%d}", object->debug_id, object->n_children); 587 if (!fscache_enqueue_dependents(object, FSCACHE_OBJECT_EV_PARENT_READY))
588 return NO_TRANSIT; /* Not finished; requeue */
589 return transit_to(WAIT_FOR_CMD);
590}
651 591
652 ASSERTCMP(object->cookie, ==, NULL); 592/*
653 ASSERT(hlist_unhashed(&object->cookie_link)); 593 * Handle lookup or creation failute.
594 */
595static const struct fscache_state *fscache_lookup_failure(struct fscache_object *object,
596 int event)
597{
598 struct fscache_cookie *cookie;
654 599
655 spin_lock(&cache->object_list_lock); 600 _enter("{OBJ%x},%d", object->debug_id, event);
656 list_del_init(&object->cache_link);
657 spin_unlock(&cache->object_list_lock);
658 601
659 fscache_stat(&fscache_n_cop_drop_object); 602 object->oob_event_mask = 0;
660 cache->ops->drop_object(object);
661 fscache_stat_d(&fscache_n_cop_drop_object);
662 603
663 if (parent) { 604 fscache_stat(&fscache_n_cop_lookup_complete);
664 _debug("release parent OBJ%x {%d}", 605 object->cache->ops->lookup_complete(object);
665 parent->debug_id, parent->n_children); 606 fscache_stat_d(&fscache_n_cop_lookup_complete);
666 607
667 spin_lock(&parent->lock); 608 cookie = object->cookie;
668 parent->n_children--; 609 set_bit(FSCACHE_COOKIE_UNAVAILABLE, &cookie->flags);
669 if (parent->n_children == 0) 610 if (test_and_clear_bit(FSCACHE_COOKIE_LOOKING_UP, &cookie->flags))
670 fscache_raise_event(parent, FSCACHE_OBJECT_EV_CLEARED); 611 wake_up_bit(&cookie->flags, FSCACHE_COOKIE_LOOKING_UP);
671 spin_unlock(&parent->lock); 612
672 object->parent = NULL; 613 fscache_done_parent_op(object);
614 return transit_to(KILL_OBJECT);
615}
616
617/*
618 * Wait for completion of all active operations on this object and the death of
619 * all child objects of this object.
620 */
621static const struct fscache_state *fscache_kill_object(struct fscache_object *object,
622 int event)
623{
624 _enter("{OBJ%x,%d,%d},%d",
625 object->debug_id, object->n_ops, object->n_children, event);
626
627 clear_bit(FSCACHE_OBJECT_IS_LIVE, &object->flags);
628 object->oob_event_mask = 0;
629
630 if (list_empty(&object->dependents) &&
631 object->n_ops == 0 &&
632 object->n_children == 0)
633 return transit_to(DROP_OBJECT);
634
635 if (object->n_in_progress == 0) {
636 spin_lock(&object->lock);
637 if (object->n_ops > 0 && object->n_in_progress == 0)
638 fscache_start_operations(object);
639 spin_unlock(&object->lock);
673 } 640 }
674 641
675 /* this just shifts the object release to the work processor */ 642 if (!list_empty(&object->dependents))
676 fscache_put_object(object); 643 return transit_to(KILL_DEPENDENTS);
677 644
678 _leave(""); 645 return transit_to(WAIT_FOR_CLEARANCE);
679} 646}
680 647
681/* 648/*
682 * release or recycle an object that the netfs has discarded 649 * Kill dependent objects.
683 */ 650 */
684static void fscache_release_object(struct fscache_object *object) 651static const struct fscache_state *fscache_kill_dependents(struct fscache_object *object,
652 int event)
685{ 653{
686 _enter(""); 654 _enter("{OBJ%x},%d", object->debug_id, event);
687 655
688 fscache_drop_object(object); 656 if (!fscache_enqueue_dependents(object, FSCACHE_OBJECT_EV_KILL))
657 return NO_TRANSIT; /* Not finished */
658 return transit_to(WAIT_FOR_CLEARANCE);
689} 659}
690 660
691/* 661/*
692 * withdraw an object from active service 662 * Drop an object's attachments
693 */ 663 */
694static void fscache_withdraw_object(struct fscache_object *object) 664static const struct fscache_state *fscache_drop_object(struct fscache_object *object,
665 int event)
695{ 666{
696 struct fscache_cookie *cookie; 667 struct fscache_object *parent = object->parent;
697 bool detached; 668 struct fscache_cookie *cookie = object->cookie;
669 struct fscache_cache *cache = object->cache;
670 bool awaken = false;
698 671
699 _enter(""); 672 _enter("{OBJ%x,%d},%d", object->debug_id, object->n_children, event);
700 673
701 spin_lock(&object->lock); 674 ASSERT(cookie != NULL);
702 cookie = object->cookie; 675 ASSERT(!hlist_unhashed(&object->cookie_link));
703 if (cookie) {
704 /* need to get the cookie lock before the object lock, starting
705 * from the object pointer */
706 atomic_inc(&cookie->usage);
707 spin_unlock(&object->lock);
708 676
709 detached = false; 677 /* Make sure the cookie no longer points here and that the netfs isn't
710 spin_lock(&cookie->lock); 678 * waiting for us.
711 spin_lock(&object->lock); 679 */
680 spin_lock(&cookie->lock);
681 hlist_del_init(&object->cookie_link);
682 if (test_and_clear_bit(FSCACHE_COOKIE_INVALIDATING, &cookie->flags))
683 awaken = true;
684 spin_unlock(&cookie->lock);
712 685
713 if (object->cookie == cookie) { 686 if (awaken)
714 hlist_del_init(&object->cookie_link); 687 wake_up_bit(&cookie->flags, FSCACHE_COOKIE_INVALIDATING);
715 object->cookie = NULL;
716 fscache_invalidation_complete(cookie);
717 detached = true;
718 }
719 spin_unlock(&cookie->lock);
720 fscache_cookie_put(cookie);
721 if (detached)
722 fscache_cookie_put(cookie);
723 }
724 688
689 /* Prevent a race with our last child, which has to signal EV_CLEARED
690 * before dropping our spinlock.
691 */
692 spin_lock(&object->lock);
725 spin_unlock(&object->lock); 693 spin_unlock(&object->lock);
726 694
727 fscache_drop_object(object); 695 /* Discard from the cache's collection of objects */
728} 696 spin_lock(&cache->object_list_lock);
697 list_del_init(&object->cache_link);
698 spin_unlock(&cache->object_list_lock);
729 699
730/* 700 fscache_stat(&fscache_n_cop_drop_object);
731 * withdraw an object from active service at the behest of the cache 701 cache->ops->drop_object(object);
732 * - need break the links to a cached object cookie 702 fscache_stat_d(&fscache_n_cop_drop_object);
733 * - called under two situations:
734 * (1) recycler decides to reclaim an in-use object
735 * (2) a cache is unmounted
736 * - have to take care as the cookie can be being relinquished by the netfs
737 * simultaneously
738 * - the object is pinned by the caller holding a refcount on it
739 */
740void fscache_withdrawing_object(struct fscache_cache *cache,
741 struct fscache_object *object)
742{
743 bool enqueue = false;
744 703
745 _enter(",OBJ%x", object->debug_id); 704 /* The parent object wants to know when all it dependents have gone */
705 if (parent) {
706 _debug("release parent OBJ%x {%d}",
707 parent->debug_id, parent->n_children);
746 708
747 spin_lock(&object->lock); 709 spin_lock(&parent->lock);
748 if (object->state < FSCACHE_OBJECT_WITHDRAWING) { 710 parent->n_children--;
749 object->state = FSCACHE_OBJECT_WITHDRAWING; 711 if (parent->n_children == 0)
750 enqueue = true; 712 fscache_raise_event(parent, FSCACHE_OBJECT_EV_CLEARED);
713 spin_unlock(&parent->lock);
714 object->parent = NULL;
751 } 715 }
752 spin_unlock(&object->lock);
753 716
754 if (enqueue) 717 /* this just shifts the object release to the work processor */
755 fscache_enqueue_object(object); 718 fscache_put_object(object);
719 fscache_stat(&fscache_n_object_dead);
756 720
757 _leave(""); 721 _leave("");
722 return transit_to(OBJECT_DEAD);
758} 723}
759 724
760/* 725/*
@@ -771,7 +736,7 @@ static int fscache_get_object(struct fscache_object *object)
771} 736}
772 737
773/* 738/*
774 * discard a ref on a work item 739 * Discard a ref on an object
775 */ 740 */
776static void fscache_put_object(struct fscache_object *object) 741static void fscache_put_object(struct fscache_object *object)
777{ 742{
@@ -780,6 +745,22 @@ static void fscache_put_object(struct fscache_object *object)
780 fscache_stat_d(&fscache_n_cop_put_object); 745 fscache_stat_d(&fscache_n_cop_put_object);
781} 746}
782 747
748/**
749 * fscache_object_destroy - Note that a cache object is about to be destroyed
750 * @object: The object to be destroyed
751 *
752 * Note the imminent destruction and deallocation of a cache object record.
753 */
754void fscache_object_destroy(struct fscache_object *object)
755{
756 fscache_objlist_remove(object);
757
758 /* We can get rid of the cookie now */
759 fscache_cookie_put(object->cookie);
760 object->cookie = NULL;
761}
762EXPORT_SYMBOL(fscache_object_destroy);
763
783/* 764/*
784 * enqueue an object for metadata-type processing 765 * enqueue an object for metadata-type processing
785 */ 766 */
@@ -803,7 +784,7 @@ void fscache_enqueue_object(struct fscache_object *object)
803 784
804/** 785/**
805 * fscache_object_sleep_till_congested - Sleep until object wq is congested 786 * fscache_object_sleep_till_congested - Sleep until object wq is congested
806 * @timoutp: Scheduler sleep timeout 787 * @timeoutp: Scheduler sleep timeout
807 * 788 *
808 * Allow an object handler to sleep until the object workqueue is congested. 789 * Allow an object handler to sleep until the object workqueue is congested.
809 * 790 *
@@ -831,18 +812,21 @@ bool fscache_object_sleep_till_congested(signed long *timeoutp)
831EXPORT_SYMBOL_GPL(fscache_object_sleep_till_congested); 812EXPORT_SYMBOL_GPL(fscache_object_sleep_till_congested);
832 813
833/* 814/*
834 * enqueue the dependents of an object for metadata-type processing 815 * Enqueue the dependents of an object for metadata-type processing.
835 * - the caller must hold the object's lock 816 *
836 * - this may cause an already locked object to wind up being processed again 817 * If we don't manage to finish the list before the scheduler wants to run
818 * again then return false immediately. We return true if the list was
819 * cleared.
837 */ 820 */
838static void fscache_enqueue_dependents(struct fscache_object *object) 821static bool fscache_enqueue_dependents(struct fscache_object *object, int event)
839{ 822{
840 struct fscache_object *dep; 823 struct fscache_object *dep;
824 bool ret = true;
841 825
842 _enter("{OBJ%x}", object->debug_id); 826 _enter("{OBJ%x}", object->debug_id);
843 827
844 if (list_empty(&object->dependents)) 828 if (list_empty(&object->dependents))
845 return; 829 return true;
846 830
847 spin_lock(&object->lock); 831 spin_lock(&object->lock);
848 832
@@ -851,23 +835,23 @@ static void fscache_enqueue_dependents(struct fscache_object *object)
851 struct fscache_object, dep_link); 835 struct fscache_object, dep_link);
852 list_del_init(&dep->dep_link); 836 list_del_init(&dep->dep_link);
853 837
854 838 fscache_raise_event(dep, event);
855 /* sort onto appropriate lists */
856 fscache_enqueue_object(dep);
857 fscache_put_object(dep); 839 fscache_put_object(dep);
858 840
859 if (!list_empty(&object->dependents)) 841 if (!list_empty(&object->dependents) && need_resched()) {
860 cond_resched_lock(&object->lock); 842 ret = false;
843 break;
844 }
861 } 845 }
862 846
863 spin_unlock(&object->lock); 847 spin_unlock(&object->lock);
848 return ret;
864} 849}
865 850
866/* 851/*
867 * remove an object from whatever queue it's waiting on 852 * remove an object from whatever queue it's waiting on
868 * - the caller must hold object->lock
869 */ 853 */
870void fscache_dequeue_object(struct fscache_object *object) 854static void fscache_dequeue_object(struct fscache_object *object)
871{ 855{
872 _enter("{OBJ%x}", object->debug_id); 856 _enter("{OBJ%x}", object->debug_id);
873 857
@@ -886,7 +870,10 @@ void fscache_dequeue_object(struct fscache_object *object)
886 * @data: The auxiliary data for the object 870 * @data: The auxiliary data for the object
887 * @datalen: The size of the auxiliary data 871 * @datalen: The size of the auxiliary data
888 * 872 *
889 * This function consults the netfs about the coherency state of an object 873 * This function consults the netfs about the coherency state of an object.
874 * The caller must be holding a ref on cookie->n_active (held by
875 * fscache_look_up_object() on behalf of the cache backend during object lookup
876 * and creation).
890 */ 877 */
891enum fscache_checkaux fscache_check_aux(struct fscache_object *object, 878enum fscache_checkaux fscache_check_aux(struct fscache_object *object,
892 const void *data, uint16_t datalen) 879 const void *data, uint16_t datalen)
@@ -927,12 +914,23 @@ EXPORT_SYMBOL(fscache_check_aux);
927/* 914/*
928 * Asynchronously invalidate an object. 915 * Asynchronously invalidate an object.
929 */ 916 */
930static void fscache_invalidate_object(struct fscache_object *object) 917static const struct fscache_state *_fscache_invalidate_object(struct fscache_object *object,
918 int event)
931{ 919{
932 struct fscache_operation *op; 920 struct fscache_operation *op;
933 struct fscache_cookie *cookie = object->cookie; 921 struct fscache_cookie *cookie = object->cookie;
934 922
935 _enter("{OBJ%x}", object->debug_id); 923 _enter("{OBJ%x},%d", object->debug_id, event);
924
925 /* We're going to need the cookie. If the cookie is not available then
926 * retire the object instead.
927 */
928 if (!fscache_use_cookie(object)) {
929 ASSERT(object->cookie->stores.rnode == NULL);
930 set_bit(FSCACHE_COOKIE_RETIRED, &cookie->flags);
931 _leave(" [no cookie]");
932 return transit_to(KILL_OBJECT);
933 }
936 934
937 /* Reject any new read/write ops and abort any that are pending. */ 935 /* Reject any new read/write ops and abort any that are pending. */
938 fscache_invalidate_writes(cookie); 936 fscache_invalidate_writes(cookie);
@@ -941,14 +939,13 @@ static void fscache_invalidate_object(struct fscache_object *object)
941 939
942 /* Now we have to wait for in-progress reads and writes */ 940 /* Now we have to wait for in-progress reads and writes */
943 op = kzalloc(sizeof(*op), GFP_KERNEL); 941 op = kzalloc(sizeof(*op), GFP_KERNEL);
944 if (!op) { 942 if (!op)
945 fscache_raise_event(object, FSCACHE_OBJECT_EV_ERROR); 943 goto nomem;
946 _leave(" [ENOMEM]");
947 return;
948 }
949 944
950 fscache_operation_init(op, object->cache->ops->invalidate_object, NULL); 945 fscache_operation_init(op, object->cache->ops->invalidate_object, NULL);
951 op->flags = FSCACHE_OP_ASYNC | (1 << FSCACHE_OP_EXCLUSIVE); 946 op->flags = FSCACHE_OP_ASYNC |
947 (1 << FSCACHE_OP_EXCLUSIVE) |
948 (1 << FSCACHE_OP_UNUSE_COOKIE);
952 949
953 spin_lock(&cookie->lock); 950 spin_lock(&cookie->lock);
954 if (fscache_submit_exclusive_op(object, op) < 0) 951 if (fscache_submit_exclusive_op(object, op) < 0)
@@ -965,13 +962,50 @@ static void fscache_invalidate_object(struct fscache_object *object)
965 /* We can allow read and write requests to come in once again. They'll 962 /* We can allow read and write requests to come in once again. They'll
966 * queue up behind our exclusive invalidation operation. 963 * queue up behind our exclusive invalidation operation.
967 */ 964 */
968 fscache_invalidation_complete(cookie); 965 if (test_and_clear_bit(FSCACHE_COOKIE_INVALIDATING, &cookie->flags))
969 _leave(""); 966 wake_up_bit(&cookie->flags, FSCACHE_COOKIE_INVALIDATING);
970 return; 967 _leave(" [ok]");
968 return transit_to(UPDATE_OBJECT);
969
970nomem:
971 clear_bit(FSCACHE_OBJECT_IS_LIVE, &object->flags);
972 fscache_unuse_cookie(object);
973 _leave(" [ENOMEM]");
974 return transit_to(KILL_OBJECT);
971 975
972submit_op_failed: 976submit_op_failed:
977 clear_bit(FSCACHE_OBJECT_IS_LIVE, &object->flags);
973 spin_unlock(&cookie->lock); 978 spin_unlock(&cookie->lock);
974 kfree(op); 979 kfree(op);
975 fscache_raise_event(object, FSCACHE_OBJECT_EV_ERROR);
976 _leave(" [EIO]"); 980 _leave(" [EIO]");
981 return transit_to(KILL_OBJECT);
982}
983
984static const struct fscache_state *fscache_invalidate_object(struct fscache_object *object,
985 int event)
986{
987 const struct fscache_state *s;
988
989 fscache_stat(&fscache_n_invalidates_run);
990 fscache_stat(&fscache_n_cop_invalidate_object);
991 s = _fscache_invalidate_object(object, event);
992 fscache_stat_d(&fscache_n_cop_invalidate_object);
993 return s;
994}
995
996/*
997 * Asynchronously update an object.
998 */
999static const struct fscache_state *fscache_update_object(struct fscache_object *object,
1000 int event)
1001{
1002 _enter("{OBJ%x},%d", object->debug_id, event);
1003
1004 fscache_stat(&fscache_n_updates_run);
1005 fscache_stat(&fscache_n_cop_update_object);
1006 object->cache->ops->update_object(object);
1007 fscache_stat_d(&fscache_n_cop_update_object);
1008
1009 _leave("");
1010 return transit_to(WAIT_FOR_CMD);
977} 1011}
generated by cgit v1.2.2 (git 2.25.0) at 2025-07-15 23:56:54 -0400