David Howells | 36c9559 | 2009-04-03 16:42:38 +0100 | [diff] [blame] | 1 | /* FS-Cache object state machine handler |
| 2 | * |
| 3 | * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved. |
| 4 | * Written by David Howells (dhowells@redhat.com) |
| 5 | * |
| 6 | * This program is free software; you can redistribute it and/or |
| 7 | * modify it under the terms of the GNU General Public License |
| 8 | * as published by the Free Software Foundation; either version |
| 9 | * 2 of the License, or (at your option) any later version. |
| 10 | * |
| 11 | * See Documentation/filesystems/caching/object.txt for a description of the |
| 12 | * object state machine and the in-kernel representations. |
| 13 | */ |
| 14 | |
| 15 | #define FSCACHE_DEBUG_LEVEL COOKIE |
| 16 | #include <linux/module.h> |
David Howells | ef778e7 | 2012-12-20 21:52:36 +0000 | [diff] [blame] | 17 | #include <linux/slab.h> |
David Howells | caaef69 | 2013-05-10 19:50:26 +0100 | [diff] [blame^] | 18 | #include <linux/prefetch.h> |
David Howells | 36c9559 | 2009-04-03 16:42:38 +0100 | [diff] [blame] | 19 | #include "internal.h" |
| 20 | |
David Howells | caaef69 | 2013-05-10 19:50:26 +0100 | [diff] [blame^] | 21 | static const struct fscache_state *fscache_abort_initialisation(struct fscache_object *, int); |
| 22 | static const struct fscache_state *fscache_kill_dependents(struct fscache_object *, int); |
| 23 | static const struct fscache_state *fscache_drop_object(struct fscache_object *, int); |
| 24 | static const struct fscache_state *fscache_initialise_object(struct fscache_object *, int); |
| 25 | static const struct fscache_state *fscache_invalidate_object(struct fscache_object *, int); |
| 26 | static const struct fscache_state *fscache_jumpstart_dependents(struct fscache_object *, int); |
| 27 | static const struct fscache_state *fscache_kill_object(struct fscache_object *, int); |
| 28 | static const struct fscache_state *fscache_lookup_failure(struct fscache_object *, int); |
| 29 | static const struct fscache_state *fscache_look_up_object(struct fscache_object *, int); |
| 30 | static const struct fscache_state *fscache_object_available(struct fscache_object *, int); |
| 31 | static const struct fscache_state *fscache_parent_ready(struct fscache_object *, int); |
| 32 | static const struct fscache_state *fscache_update_object(struct fscache_object *, int); |
| 33 | static const struct fscache_state *fscache_detach_from_cookie(struct fscache_object *, int); |
David Howells | 36c9559 | 2009-04-03 16:42:38 +0100 | [diff] [blame] | 34 | |
David Howells | caaef69 | 2013-05-10 19:50:26 +0100 | [diff] [blame^] | 35 | #define __STATE_NAME(n) fscache_osm_##n |
| 36 | #define STATE(n) (&__STATE_NAME(n)) |
| 37 | |
| 38 | /* |
| 39 | * Define a work state. Work states are execution states. No event processing |
| 40 | * is performed by them. The function attached to a work state returns a |
| 41 | * pointer indicating the next state to which the state machine should |
| 42 | * transition. Returning NO_TRANSIT repeats the current state, but goes back |
| 43 | * to the scheduler first. |
| 44 | */ |
| 45 | #define WORK_STATE(n, sn, f) \ |
| 46 | const struct fscache_state __STATE_NAME(n) = { \ |
| 47 | .name = #n, \ |
| 48 | .short_name = sn, \ |
| 49 | .work = f \ |
| 50 | } |
| 51 | |
| 52 | /* |
| 53 | * Returns from work states. |
| 54 | */ |
| 55 | #define transit_to(state) ({ prefetch(&STATE(state)->work); STATE(state); }) |
| 56 | |
| 57 | #define NO_TRANSIT ((struct fscache_state *)NULL) |
| 58 | |
| 59 | /* |
| 60 | * Define a wait state. Wait states are event processing states. No execution |
| 61 | * is performed by them. Wait states are just tables of "if event X occurs, |
| 62 | * clear it and transition to state Y". The dispatcher returns to the |
| 63 | * scheduler if none of the events in which the wait state has an interest are |
| 64 | * currently pending. |
| 65 | */ |
| 66 | #define WAIT_STATE(n, sn, ...) \ |
| 67 | const struct fscache_state __STATE_NAME(n) = { \ |
| 68 | .name = #n, \ |
| 69 | .short_name = sn, \ |
| 70 | .work = NULL, \ |
| 71 | .transitions = { __VA_ARGS__, { 0, NULL } } \ |
| 72 | } |
| 73 | |
| 74 | #define TRANSIT_TO(state, emask) \ |
| 75 | { .events = (emask), .transit_to = STATE(state) } |
| 76 | |
| 77 | /* |
| 78 | * The object state machine. |
| 79 | */ |
| 80 | static WORK_STATE(INIT_OBJECT, "INIT", fscache_initialise_object); |
| 81 | static WORK_STATE(PARENT_READY, "PRDY", fscache_parent_ready); |
| 82 | static WORK_STATE(ABORT_INIT, "ABRT", fscache_abort_initialisation); |
| 83 | static WORK_STATE(LOOK_UP_OBJECT, "LOOK", fscache_look_up_object); |
| 84 | static WORK_STATE(CREATE_OBJECT, "CRTO", fscache_look_up_object); |
| 85 | static WORK_STATE(OBJECT_AVAILABLE, "AVBL", fscache_object_available); |
| 86 | static WORK_STATE(JUMPSTART_DEPS, "JUMP", fscache_jumpstart_dependents); |
| 87 | |
| 88 | static WORK_STATE(INVALIDATE_OBJECT, "INVL", fscache_invalidate_object); |
| 89 | static WORK_STATE(UPDATE_OBJECT, "UPDT", fscache_update_object); |
| 90 | |
| 91 | static WORK_STATE(LOOKUP_FAILURE, "LCFL", fscache_lookup_failure); |
| 92 | static WORK_STATE(KILL_OBJECT, "KILL", fscache_kill_object); |
| 93 | static WORK_STATE(KILL_DEPENDENTS, "KDEP", fscache_kill_dependents); |
| 94 | static WORK_STATE(DROP_OBJECT, "DROP", fscache_drop_object); |
| 95 | static WORK_STATE(DETACH_FROM_COOKIE, "DTCH", fscache_detach_from_cookie); |
| 96 | static WORK_STATE(OBJECT_DEAD, "DEAD", (void*)2UL); |
| 97 | |
| 98 | static WAIT_STATE(WAIT_FOR_INIT, "?INI", |
| 99 | TRANSIT_TO(INIT_OBJECT, 1 << FSCACHE_OBJECT_EV_NEW_CHILD)); |
| 100 | |
| 101 | static WAIT_STATE(WAIT_FOR_PARENT, "?PRN", |
| 102 | TRANSIT_TO(PARENT_READY, 1 << FSCACHE_OBJECT_EV_PARENT_READY)); |
| 103 | |
| 104 | static WAIT_STATE(WAIT_FOR_CMD, "?CMD", |
| 105 | TRANSIT_TO(INVALIDATE_OBJECT, 1 << FSCACHE_OBJECT_EV_INVALIDATE), |
| 106 | TRANSIT_TO(UPDATE_OBJECT, 1 << FSCACHE_OBJECT_EV_UPDATE), |
| 107 | TRANSIT_TO(JUMPSTART_DEPS, 1 << FSCACHE_OBJECT_EV_NEW_CHILD)); |
| 108 | |
| 109 | static WAIT_STATE(WAIT_FOR_CLEARANCE, "?CLR", |
| 110 | TRANSIT_TO(KILL_OBJECT, 1 << FSCACHE_OBJECT_EV_CLEARED)); |
| 111 | |
| 112 | /* |
| 113 | * Out-of-band event transition tables. These are for handling unexpected |
| 114 | * events, such as an I/O error. If an OOB event occurs, the state machine |
| 115 | * clears and disables the event and forces a transition to the nominated work |
| 116 | * state (acurrently executing work states will complete first). |
| 117 | * |
| 118 | * In such a situation, object->state remembers the state the machine should |
| 119 | * have been in/gone to and returning NO_TRANSIT returns to that. |
| 120 | */ |
| 121 | static const struct fscache_transition fscache_osm_init_oob[] = { |
| 122 | TRANSIT_TO(ABORT_INIT, |
| 123 | (1 << FSCACHE_OBJECT_EV_ERROR) | |
| 124 | (1 << FSCACHE_OBJECT_EV_KILL)), |
| 125 | { 0, NULL } |
| 126 | }; |
| 127 | |
| 128 | static const struct fscache_transition fscache_osm_lookup_oob[] = { |
| 129 | TRANSIT_TO(LOOKUP_FAILURE, |
| 130 | (1 << FSCACHE_OBJECT_EV_ERROR) | |
| 131 | (1 << FSCACHE_OBJECT_EV_KILL)), |
| 132 | { 0, NULL } |
| 133 | }; |
| 134 | |
| 135 | static const struct fscache_transition fscache_osm_run_oob[] = { |
| 136 | TRANSIT_TO(KILL_OBJECT, |
| 137 | (1 << FSCACHE_OBJECT_EV_ERROR) | |
| 138 | (1 << FSCACHE_OBJECT_EV_KILL)), |
| 139 | { 0, NULL } |
David Howells | 440f0af | 2009-11-19 18:11:01 +0000 | [diff] [blame] | 140 | }; |
| 141 | |
Tejun Heo | 8b8edef | 2010-07-20 22:09:01 +0200 | [diff] [blame] | 142 | static int fscache_get_object(struct fscache_object *); |
| 143 | static void fscache_put_object(struct fscache_object *); |
David Howells | caaef69 | 2013-05-10 19:50:26 +0100 | [diff] [blame^] | 144 | static bool fscache_enqueue_dependents(struct fscache_object *, int); |
David Howells | 36c9559 | 2009-04-03 16:42:38 +0100 | [diff] [blame] | 145 | static void fscache_dequeue_object(struct fscache_object *); |
| 146 | |
David Howells | 36c9559 | 2009-04-03 16:42:38 +0100 | [diff] [blame] | 147 | /* |
| 148 | * we need to notify the parent when an op completes that we had outstanding |
| 149 | * upon it |
| 150 | */ |
| 151 | static inline void fscache_done_parent_op(struct fscache_object *object) |
| 152 | { |
| 153 | struct fscache_object *parent = object->parent; |
| 154 | |
| 155 | _enter("OBJ%x {OBJ%x,%x}", |
| 156 | object->debug_id, parent->debug_id, parent->n_ops); |
| 157 | |
| 158 | spin_lock_nested(&parent->lock, 1); |
| 159 | parent->n_ops--; |
| 160 | parent->n_obj_ops--; |
| 161 | if (parent->n_ops == 0) |
| 162 | fscache_raise_event(parent, FSCACHE_OBJECT_EV_CLEARED); |
| 163 | spin_unlock(&parent->lock); |
| 164 | } |
| 165 | |
| 166 | /* |
David Howells | caaef69 | 2013-05-10 19:50:26 +0100 | [diff] [blame^] | 167 | * Object state machine dispatcher. |
David Howells | ef778e7 | 2012-12-20 21:52:36 +0000 | [diff] [blame] | 168 | */ |
David Howells | caaef69 | 2013-05-10 19:50:26 +0100 | [diff] [blame^] | 169 | static void fscache_object_sm_dispatcher(struct fscache_object *object) |
David Howells | ef778e7 | 2012-12-20 21:52:36 +0000 | [diff] [blame] | 170 | { |
David Howells | caaef69 | 2013-05-10 19:50:26 +0100 | [diff] [blame^] | 171 | const struct fscache_transition *t; |
| 172 | const struct fscache_state *state, *new_state; |
| 173 | unsigned long events, event_mask; |
| 174 | int event = -1; |
David Howells | 36c9559 | 2009-04-03 16:42:38 +0100 | [diff] [blame] | 175 | |
| 176 | ASSERT(object != NULL); |
| 177 | |
| 178 | _enter("{OBJ%x,%s,%lx}", |
David Howells | caaef69 | 2013-05-10 19:50:26 +0100 | [diff] [blame^] | 179 | object->debug_id, object->state->name, object->events); |
David Howells | 36c9559 | 2009-04-03 16:42:38 +0100 | [diff] [blame] | 180 | |
David Howells | caaef69 | 2013-05-10 19:50:26 +0100 | [diff] [blame^] | 181 | event_mask = object->event_mask; |
| 182 | restart: |
| 183 | object->event_mask = 0; /* Mask normal event handling */ |
| 184 | state = object->state; |
| 185 | restart_masked: |
| 186 | events = object->events; |
David Howells | 36c9559 | 2009-04-03 16:42:38 +0100 | [diff] [blame] | 187 | |
David Howells | caaef69 | 2013-05-10 19:50:26 +0100 | [diff] [blame^] | 188 | /* Handle any out-of-band events (typically an error) */ |
| 189 | if (events & object->oob_event_mask) { |
| 190 | _debug("{OBJ%x} oob %lx", |
| 191 | object->debug_id, events & object->oob_event_mask); |
| 192 | for (t = object->oob_table; t->events; t++) { |
| 193 | if (events & t->events) { |
| 194 | state = t->transit_to; |
| 195 | ASSERT(state->work != NULL); |
| 196 | event = fls(events & t->events) - 1; |
| 197 | __clear_bit(event, &object->oob_event_mask); |
| 198 | clear_bit(event, &object->events); |
| 199 | goto execute_work_state; |
| 200 | } |
David Howells | d461d26 | 2009-11-19 18:11:41 +0000 | [diff] [blame] | 201 | } |
David Howells | caaef69 | 2013-05-10 19:50:26 +0100 | [diff] [blame^] | 202 | } |
David Howells | 36c9559 | 2009-04-03 16:42:38 +0100 | [diff] [blame] | 203 | |
David Howells | caaef69 | 2013-05-10 19:50:26 +0100 | [diff] [blame^] | 204 | /* Wait states are just transition tables */ |
| 205 | if (!state->work) { |
| 206 | if (events & event_mask) { |
| 207 | for (t = state->transitions; t->events; t++) { |
| 208 | if (events & t->events) { |
| 209 | new_state = t->transit_to; |
| 210 | event = fls(events & t->events) - 1; |
| 211 | clear_bit(event, &object->events); |
| 212 | _debug("{OBJ%x} ev %d: %s -> %s", |
| 213 | object->debug_id, event, |
| 214 | state->name, new_state->name); |
| 215 | object->state = state = new_state; |
| 216 | goto execute_work_state; |
| 217 | } |
| 218 | } |
David Howells | 36c9559 | 2009-04-03 16:42:38 +0100 | [diff] [blame] | 219 | |
David Howells | caaef69 | 2013-05-10 19:50:26 +0100 | [diff] [blame^] | 220 | /* The event mask didn't include all the tabled bits */ |
| 221 | BUG(); |
David Howells | 36c9559 | 2009-04-03 16:42:38 +0100 | [diff] [blame] | 222 | } |
David Howells | caaef69 | 2013-05-10 19:50:26 +0100 | [diff] [blame^] | 223 | /* Randomly woke up */ |
| 224 | goto unmask_events; |
David Howells | 36c9559 | 2009-04-03 16:42:38 +0100 | [diff] [blame] | 225 | } |
| 226 | |
David Howells | caaef69 | 2013-05-10 19:50:26 +0100 | [diff] [blame^] | 227 | execute_work_state: |
| 228 | _debug("{OBJ%x} exec %s", object->debug_id, state->name); |
| 229 | |
| 230 | new_state = state->work(object, event); |
| 231 | event = -1; |
| 232 | if (new_state == NO_TRANSIT) { |
| 233 | _debug("{OBJ%x} %s notrans", object->debug_id, state->name); |
| 234 | fscache_enqueue_object(object); |
| 235 | event_mask = object->oob_event_mask; |
| 236 | goto unmask_events; |
David Howells | 36c9559 | 2009-04-03 16:42:38 +0100 | [diff] [blame] | 237 | } |
| 238 | |
David Howells | caaef69 | 2013-05-10 19:50:26 +0100 | [diff] [blame^] | 239 | _debug("{OBJ%x} %s -> %s", |
| 240 | object->debug_id, state->name, new_state->name); |
| 241 | object->state = state = new_state; |
| 242 | |
| 243 | if (state->work) { |
| 244 | if (unlikely(state->work == ((void *)2UL))) { |
| 245 | _leave(" [dead]"); |
| 246 | return; |
| 247 | } |
| 248 | goto restart_masked; |
David Howells | 36c9559 | 2009-04-03 16:42:38 +0100 | [diff] [blame] | 249 | } |
| 250 | |
David Howells | caaef69 | 2013-05-10 19:50:26 +0100 | [diff] [blame^] | 251 | /* Transited to wait state */ |
| 252 | event_mask = object->oob_event_mask; |
| 253 | for (t = state->transitions; t->events; t++) |
| 254 | event_mask |= t->events; |
David Howells | 36c9559 | 2009-04-03 16:42:38 +0100 | [diff] [blame] | 255 | |
David Howells | caaef69 | 2013-05-10 19:50:26 +0100 | [diff] [blame^] | 256 | unmask_events: |
| 257 | object->event_mask = event_mask; |
| 258 | smp_mb(); |
| 259 | events = object->events; |
| 260 | if (events & event_mask) |
| 261 | goto restart; |
| 262 | _leave(" [msk %lx]", event_mask); |
David Howells | 36c9559 | 2009-04-03 16:42:38 +0100 | [diff] [blame] | 263 | } |
| 264 | |
| 265 | /* |
| 266 | * execute an object |
| 267 | */ |
David Howells | 610be24 | 2013-05-10 19:50:25 +0100 | [diff] [blame] | 268 | static void fscache_object_work_func(struct work_struct *work) |
David Howells | 36c9559 | 2009-04-03 16:42:38 +0100 | [diff] [blame] | 269 | { |
| 270 | struct fscache_object *object = |
| 271 | container_of(work, struct fscache_object, work); |
| 272 | unsigned long start; |
| 273 | |
| 274 | _enter("{OBJ%x}", object->debug_id); |
| 275 | |
David Howells | 36c9559 | 2009-04-03 16:42:38 +0100 | [diff] [blame] | 276 | start = jiffies; |
David Howells | caaef69 | 2013-05-10 19:50:26 +0100 | [diff] [blame^] | 277 | fscache_object_sm_dispatcher(object); |
David Howells | 36c9559 | 2009-04-03 16:42:38 +0100 | [diff] [blame] | 278 | fscache_hist(fscache_objs_histogram, start); |
Tejun Heo | 8b8edef | 2010-07-20 22:09:01 +0200 | [diff] [blame] | 279 | fscache_put_object(object); |
David Howells | 36c9559 | 2009-04-03 16:42:38 +0100 | [diff] [blame] | 280 | } |
David Howells | 610be24 | 2013-05-10 19:50:25 +0100 | [diff] [blame] | 281 | |
| 282 | /** |
| 283 | * fscache_object_init - Initialise a cache object description |
| 284 | * @object: Object description |
| 285 | * @cookie: Cookie object will be attached to |
| 286 | * @cache: Cache in which backing object will be found |
| 287 | * |
| 288 | * Initialise a cache object description to its basic values. |
| 289 | * |
| 290 | * See Documentation/filesystems/caching/backend-api.txt for a complete |
| 291 | * description. |
| 292 | */ |
| 293 | void fscache_object_init(struct fscache_object *object, |
| 294 | struct fscache_cookie *cookie, |
| 295 | struct fscache_cache *cache) |
| 296 | { |
David Howells | caaef69 | 2013-05-10 19:50:26 +0100 | [diff] [blame^] | 297 | const struct fscache_transition *t; |
| 298 | |
David Howells | 610be24 | 2013-05-10 19:50:25 +0100 | [diff] [blame] | 299 | atomic_inc(&cache->object_count); |
| 300 | |
David Howells | caaef69 | 2013-05-10 19:50:26 +0100 | [diff] [blame^] | 301 | object->state = STATE(WAIT_FOR_INIT); |
| 302 | object->oob_table = fscache_osm_init_oob; |
| 303 | object->flags = 1 << FSCACHE_OBJECT_IS_LIVE; |
David Howells | 610be24 | 2013-05-10 19:50:25 +0100 | [diff] [blame] | 304 | spin_lock_init(&object->lock); |
| 305 | INIT_LIST_HEAD(&object->cache_link); |
| 306 | INIT_HLIST_NODE(&object->cookie_link); |
| 307 | INIT_WORK(&object->work, fscache_object_work_func); |
| 308 | INIT_LIST_HEAD(&object->dependents); |
| 309 | INIT_LIST_HEAD(&object->dep_link); |
| 310 | INIT_LIST_HEAD(&object->pending_ops); |
| 311 | object->n_children = 0; |
| 312 | object->n_ops = object->n_in_progress = object->n_exclusive = 0; |
David Howells | caaef69 | 2013-05-10 19:50:26 +0100 | [diff] [blame^] | 313 | object->events = 0; |
David Howells | 610be24 | 2013-05-10 19:50:25 +0100 | [diff] [blame] | 314 | object->store_limit = 0; |
| 315 | object->store_limit_l = 0; |
| 316 | object->cache = cache; |
| 317 | object->cookie = cookie; |
| 318 | object->parent = NULL; |
David Howells | caaef69 | 2013-05-10 19:50:26 +0100 | [diff] [blame^] | 319 | |
| 320 | object->oob_event_mask = 0; |
| 321 | for (t = object->oob_table; t->events; t++) |
| 322 | object->oob_event_mask |= t->events; |
| 323 | object->event_mask = object->oob_event_mask; |
| 324 | for (t = object->state->transitions; t->events; t++) |
| 325 | object->event_mask |= t->events; |
David Howells | 610be24 | 2013-05-10 19:50:25 +0100 | [diff] [blame] | 326 | } |
| 327 | EXPORT_SYMBOL(fscache_object_init); |
David Howells | 440f0af | 2009-11-19 18:11:01 +0000 | [diff] [blame] | 328 | |
| 329 | /* |
David Howells | caaef69 | 2013-05-10 19:50:26 +0100 | [diff] [blame^] | 330 | * Abort object initialisation before we start it. |
| 331 | */ |
| 332 | static const struct fscache_state *fscache_abort_initialisation(struct fscache_object *object, |
| 333 | int event) |
| 334 | { |
| 335 | struct fscache_cookie *cookie; |
| 336 | |
| 337 | _enter("{OBJ%x},%d", object->debug_id, event); |
| 338 | |
| 339 | object->oob_event_mask = 0; |
| 340 | clear_bit(FSCACHE_OBJECT_IS_LIVE, &object->flags); |
| 341 | |
| 342 | fscache_dequeue_object(object); |
| 343 | |
| 344 | spin_lock(&object->lock); |
| 345 | cookie = object->cookie; |
| 346 | clear_bit_unlock(FSCACHE_COOKIE_CREATING, &cookie->flags); |
| 347 | spin_unlock(&object->lock); |
| 348 | |
| 349 | wake_up_bit(&cookie->flags, FSCACHE_COOKIE_CREATING); |
| 350 | |
| 351 | return transit_to(KILL_OBJECT); |
| 352 | } |
| 353 | |
| 354 | /* |
David Howells | 36c9559 | 2009-04-03 16:42:38 +0100 | [diff] [blame] | 355 | * initialise an object |
| 356 | * - check the specified object's parent to see if we can make use of it |
| 357 | * immediately to do a creation |
| 358 | * - we may need to start the process of creating a parent and we need to wait |
| 359 | * for the parent's lookup and creation to complete if it's not there yet |
| 360 | * - an object's cookie is pinned until we clear FSCACHE_COOKIE_CREATING on the |
| 361 | * leaf-most cookies of the object and all its children |
| 362 | */ |
David Howells | caaef69 | 2013-05-10 19:50:26 +0100 | [diff] [blame^] | 363 | static const struct fscache_state *fscache_initialise_object(struct fscache_object *object, |
| 364 | int event) |
David Howells | 36c9559 | 2009-04-03 16:42:38 +0100 | [diff] [blame] | 365 | { |
| 366 | struct fscache_object *parent; |
David Howells | caaef69 | 2013-05-10 19:50:26 +0100 | [diff] [blame^] | 367 | bool success; |
David Howells | 36c9559 | 2009-04-03 16:42:38 +0100 | [diff] [blame] | 368 | |
David Howells | caaef69 | 2013-05-10 19:50:26 +0100 | [diff] [blame^] | 369 | _enter("{OBJ%x},%d", object->debug_id, event); |
David Howells | 36c9559 | 2009-04-03 16:42:38 +0100 | [diff] [blame] | 370 | |
David Howells | caaef69 | 2013-05-10 19:50:26 +0100 | [diff] [blame^] | 371 | ASSERT(list_empty(&object->dep_link)); |
David Howells | 36c9559 | 2009-04-03 16:42:38 +0100 | [diff] [blame] | 372 | |
| 373 | parent = object->parent; |
| 374 | if (!parent) { |
David Howells | caaef69 | 2013-05-10 19:50:26 +0100 | [diff] [blame^] | 375 | _leave(" [no parent]"); |
| 376 | return transit_to(DETACH_FROM_COOKIE); |
David Howells | 36c9559 | 2009-04-03 16:42:38 +0100 | [diff] [blame] | 377 | } |
| 378 | |
David Howells | caaef69 | 2013-05-10 19:50:26 +0100 | [diff] [blame^] | 379 | _debug("parent %s", parent->state->name); |
| 380 | |
| 381 | if (fscache_object_is_dying(parent)) { |
| 382 | _leave(" [bad parent]"); |
| 383 | return transit_to(DETACH_FROM_COOKIE); |
| 384 | } |
| 385 | |
| 386 | if (fscache_object_is_available(parent)) { |
| 387 | _leave(" [ready]"); |
| 388 | return transit_to(PARENT_READY); |
| 389 | } |
| 390 | |
| 391 | _debug("wait"); |
| 392 | |
| 393 | spin_lock(&parent->lock); |
| 394 | fscache_stat(&fscache_n_cop_grab_object); |
| 395 | success = false; |
| 396 | if (fscache_object_is_live(parent) && |
| 397 | object->cache->ops->grab_object(object)) { |
| 398 | list_add(&object->dep_link, &parent->dependents); |
| 399 | success = true; |
| 400 | } |
| 401 | fscache_stat_d(&fscache_n_cop_grab_object); |
| 402 | spin_unlock(&parent->lock); |
| 403 | if (!success) { |
| 404 | _leave(" [grab failed]"); |
| 405 | return transit_to(DETACH_FROM_COOKIE); |
| 406 | } |
| 407 | |
| 408 | /* fscache_acquire_non_index_cookie() uses this |
| 409 | * to wake the chain up */ |
| 410 | fscache_raise_event(parent, FSCACHE_OBJECT_EV_NEW_CHILD); |
| 411 | _leave(" [wait]"); |
| 412 | return transit_to(WAIT_FOR_PARENT); |
| 413 | } |
| 414 | |
| 415 | /* |
| 416 | * Once the parent object is ready, we should kick off our lookup op. |
| 417 | */ |
| 418 | static const struct fscache_state *fscache_parent_ready(struct fscache_object *object, |
| 419 | int event) |
| 420 | { |
| 421 | struct fscache_object *parent = object->parent; |
| 422 | |
| 423 | _enter("{OBJ%x},%d", object->debug_id, event); |
| 424 | |
| 425 | ASSERT(parent != NULL); |
| 426 | |
| 427 | spin_lock(&parent->lock); |
| 428 | parent->n_ops++; |
| 429 | parent->n_obj_ops++; |
| 430 | object->lookup_jif = jiffies; |
| 431 | spin_unlock(&parent->lock); |
| 432 | |
David Howells | 36c9559 | 2009-04-03 16:42:38 +0100 | [diff] [blame] | 433 | _leave(""); |
David Howells | caaef69 | 2013-05-10 19:50:26 +0100 | [diff] [blame^] | 434 | return transit_to(LOOK_UP_OBJECT); |
David Howells | 36c9559 | 2009-04-03 16:42:38 +0100 | [diff] [blame] | 435 | } |
| 436 | |
| 437 | /* |
| 438 | * look an object up in the cache from which it was allocated |
| 439 | * - we hold an "access lock" on the parent object, so the parent object cannot |
| 440 | * be withdrawn by either party till we've finished |
| 441 | * - an object's cookie is pinned until we clear FSCACHE_COOKIE_CREATING on the |
| 442 | * leaf-most cookies of the object and all its children |
| 443 | */ |
David Howells | caaef69 | 2013-05-10 19:50:26 +0100 | [diff] [blame^] | 444 | static const struct fscache_state *fscache_look_up_object(struct fscache_object *object, |
| 445 | int event) |
David Howells | 36c9559 | 2009-04-03 16:42:38 +0100 | [diff] [blame] | 446 | { |
| 447 | struct fscache_cookie *cookie = object->cookie; |
David Howells | caaef69 | 2013-05-10 19:50:26 +0100 | [diff] [blame^] | 448 | struct fscache_object *parent = object->parent; |
David Howells | fee096d | 2009-11-19 18:12:05 +0000 | [diff] [blame] | 449 | int ret; |
David Howells | 36c9559 | 2009-04-03 16:42:38 +0100 | [diff] [blame] | 450 | |
David Howells | caaef69 | 2013-05-10 19:50:26 +0100 | [diff] [blame^] | 451 | _enter("{OBJ%x},%d", object->debug_id, event); |
David Howells | 36c9559 | 2009-04-03 16:42:38 +0100 | [diff] [blame] | 452 | |
David Howells | caaef69 | 2013-05-10 19:50:26 +0100 | [diff] [blame^] | 453 | object->oob_table = fscache_osm_lookup_oob; |
| 454 | |
David Howells | 36c9559 | 2009-04-03 16:42:38 +0100 | [diff] [blame] | 455 | ASSERT(parent != NULL); |
| 456 | ASSERTCMP(parent->n_ops, >, 0); |
| 457 | ASSERTCMP(parent->n_obj_ops, >, 0); |
| 458 | |
| 459 | /* make sure the parent is still available */ |
David Howells | 493f7bc | 2013-05-10 19:50:26 +0100 | [diff] [blame] | 460 | ASSERT(fscache_object_is_available(parent)); |
David Howells | 36c9559 | 2009-04-03 16:42:38 +0100 | [diff] [blame] | 461 | |
David Howells | 493f7bc | 2013-05-10 19:50:26 +0100 | [diff] [blame] | 462 | if (fscache_object_is_dying(parent) || |
David Howells | 36c9559 | 2009-04-03 16:42:38 +0100 | [diff] [blame] | 463 | test_bit(FSCACHE_IOERROR, &object->cache->flags)) { |
David Howells | caaef69 | 2013-05-10 19:50:26 +0100 | [diff] [blame^] | 464 | _leave(" [unavailable]"); |
| 465 | return transit_to(LOOKUP_FAILURE); |
David Howells | 36c9559 | 2009-04-03 16:42:38 +0100 | [diff] [blame] | 466 | } |
| 467 | |
| 468 | _debug("LOOKUP \"%s/%s\" in \"%s\"", |
| 469 | parent->cookie->def->name, cookie->def->name, |
| 470 | object->cache->tag->name); |
| 471 | |
| 472 | fscache_stat(&fscache_n_object_lookups); |
David Howells | 52bd75f | 2009-11-19 18:11:08 +0000 | [diff] [blame] | 473 | fscache_stat(&fscache_n_cop_lookup_object); |
David Howells | fee096d | 2009-11-19 18:12:05 +0000 | [diff] [blame] | 474 | ret = object->cache->ops->lookup_object(object); |
David Howells | 52bd75f | 2009-11-19 18:11:08 +0000 | [diff] [blame] | 475 | fscache_stat_d(&fscache_n_cop_lookup_object); |
David Howells | 36c9559 | 2009-04-03 16:42:38 +0100 | [diff] [blame] | 476 | |
| 477 | if (test_bit(FSCACHE_OBJECT_EV_ERROR, &object->events)) |
| 478 | set_bit(FSCACHE_COOKIE_UNAVAILABLE, &cookie->flags); |
| 479 | |
David Howells | fee096d | 2009-11-19 18:12:05 +0000 | [diff] [blame] | 480 | if (ret == -ETIMEDOUT) { |
| 481 | /* probably stuck behind another object, so move this one to |
| 482 | * the back of the queue */ |
| 483 | fscache_stat(&fscache_n_object_lookups_timed_out); |
David Howells | caaef69 | 2013-05-10 19:50:26 +0100 | [diff] [blame^] | 484 | _leave(" [timeout]"); |
| 485 | return NO_TRANSIT; |
David Howells | fee096d | 2009-11-19 18:12:05 +0000 | [diff] [blame] | 486 | } |
| 487 | |
David Howells | caaef69 | 2013-05-10 19:50:26 +0100 | [diff] [blame^] | 488 | if (ret < 0) { |
| 489 | _leave(" [error]"); |
| 490 | return transit_to(LOOKUP_FAILURE); |
| 491 | } |
| 492 | |
| 493 | _leave(" [ok]"); |
| 494 | return transit_to(OBJECT_AVAILABLE); |
David Howells | 36c9559 | 2009-04-03 16:42:38 +0100 | [diff] [blame] | 495 | } |
| 496 | |
| 497 | /** |
| 498 | * fscache_object_lookup_negative - Note negative cookie lookup |
| 499 | * @object: Object pointing to cookie to mark |
| 500 | * |
| 501 | * Note negative lookup, permitting those waiting to read data from an already |
| 502 | * existing backing object to continue as there's no data for them to read. |
| 503 | */ |
| 504 | void fscache_object_lookup_negative(struct fscache_object *object) |
| 505 | { |
| 506 | struct fscache_cookie *cookie = object->cookie; |
| 507 | |
David Howells | caaef69 | 2013-05-10 19:50:26 +0100 | [diff] [blame^] | 508 | _enter("{OBJ%x,%s}", object->debug_id, object->state->name); |
David Howells | 36c9559 | 2009-04-03 16:42:38 +0100 | [diff] [blame] | 509 | |
David Howells | caaef69 | 2013-05-10 19:50:26 +0100 | [diff] [blame^] | 510 | if (!test_and_set_bit(FSCACHE_OBJECT_IS_LOOKED_UP, &object->flags)) { |
David Howells | 36c9559 | 2009-04-03 16:42:38 +0100 | [diff] [blame] | 511 | fscache_stat(&fscache_n_object_lookups_negative); |
| 512 | |
David Howells | caaef69 | 2013-05-10 19:50:26 +0100 | [diff] [blame^] | 513 | /* Allow write requests to begin stacking up and read requests to begin |
| 514 | * returning ENODATA. |
| 515 | */ |
David Howells | 36c9559 | 2009-04-03 16:42:38 +0100 | [diff] [blame] | 516 | set_bit(FSCACHE_COOKIE_NO_DATA_YET, &cookie->flags); |
| 517 | |
| 518 | _debug("wake up lookup %p", &cookie->flags); |
David Howells | caaef69 | 2013-05-10 19:50:26 +0100 | [diff] [blame^] | 519 | clear_bit_unlock(FSCACHE_COOKIE_LOOKING_UP, &cookie->flags); |
David Howells | 36c9559 | 2009-04-03 16:42:38 +0100 | [diff] [blame] | 520 | wake_up_bit(&cookie->flags, FSCACHE_COOKIE_LOOKING_UP); |
David Howells | 36c9559 | 2009-04-03 16:42:38 +0100 | [diff] [blame] | 521 | } |
David Howells | 36c9559 | 2009-04-03 16:42:38 +0100 | [diff] [blame] | 522 | _leave(""); |
| 523 | } |
| 524 | EXPORT_SYMBOL(fscache_object_lookup_negative); |
| 525 | |
| 526 | /** |
| 527 | * fscache_obtained_object - Note successful object lookup or creation |
| 528 | * @object: Object pointing to cookie to mark |
| 529 | * |
| 530 | * Note successful lookup and/or creation, permitting those waiting to write |
| 531 | * data to a backing object to continue. |
| 532 | * |
| 533 | * Note that after calling this, an object's cookie may be relinquished by the |
| 534 | * netfs, and so must be accessed with object lock held. |
| 535 | */ |
| 536 | void fscache_obtained_object(struct fscache_object *object) |
| 537 | { |
| 538 | struct fscache_cookie *cookie = object->cookie; |
| 539 | |
David Howells | caaef69 | 2013-05-10 19:50:26 +0100 | [diff] [blame^] | 540 | _enter("{OBJ%x,%s}", object->debug_id, object->state->name); |
David Howells | 36c9559 | 2009-04-03 16:42:38 +0100 | [diff] [blame] | 541 | |
| 542 | /* if we were still looking up, then we must have a positive lookup |
| 543 | * result, in which case there may be data available */ |
David Howells | caaef69 | 2013-05-10 19:50:26 +0100 | [diff] [blame^] | 544 | if (!test_and_set_bit(FSCACHE_OBJECT_IS_LOOKED_UP, &object->flags)) { |
David Howells | 36c9559 | 2009-04-03 16:42:38 +0100 | [diff] [blame] | 545 | fscache_stat(&fscache_n_object_lookups_positive); |
| 546 | |
David Howells | caaef69 | 2013-05-10 19:50:26 +0100 | [diff] [blame^] | 547 | /* We do (presumably) have data */ |
| 548 | clear_bit_unlock(FSCACHE_COOKIE_NO_DATA_YET, &cookie->flags); |
David Howells | 36c9559 | 2009-04-03 16:42:38 +0100 | [diff] [blame] | 549 | |
David Howells | caaef69 | 2013-05-10 19:50:26 +0100 | [diff] [blame^] | 550 | /* Allow write requests to begin stacking up and read requests |
| 551 | * to begin shovelling data. |
| 552 | */ |
| 553 | clear_bit_unlock(FSCACHE_COOKIE_LOOKING_UP, &cookie->flags); |
David Howells | 36c9559 | 2009-04-03 16:42:38 +0100 | [diff] [blame] | 554 | wake_up_bit(&cookie->flags, FSCACHE_COOKIE_LOOKING_UP); |
David Howells | 36c9559 | 2009-04-03 16:42:38 +0100 | [diff] [blame] | 555 | } else { |
David Howells | 36c9559 | 2009-04-03 16:42:38 +0100 | [diff] [blame] | 556 | fscache_stat(&fscache_n_object_created); |
David Howells | 36c9559 | 2009-04-03 16:42:38 +0100 | [diff] [blame] | 557 | } |
| 558 | |
David Howells | caaef69 | 2013-05-10 19:50:26 +0100 | [diff] [blame^] | 559 | set_bit(FSCACHE_OBJECT_IS_AVAILABLE, &object->flags); |
| 560 | |
| 561 | /* Permit __fscache_relinquish_cookie() to proceed */ |
| 562 | clear_bit_unlock(FSCACHE_COOKIE_CREATING, &cookie->flags); |
| 563 | wake_up_bit(&cookie->flags, FSCACHE_COOKIE_CREATING); |
David Howells | 36c9559 | 2009-04-03 16:42:38 +0100 | [diff] [blame] | 564 | |
| 565 | _leave(""); |
| 566 | } |
| 567 | EXPORT_SYMBOL(fscache_obtained_object); |
| 568 | |
| 569 | /* |
| 570 | * handle an object that has just become available |
| 571 | */ |
David Howells | caaef69 | 2013-05-10 19:50:26 +0100 | [diff] [blame^] | 572 | static const struct fscache_state *fscache_object_available(struct fscache_object *object, |
| 573 | int event) |
David Howells | 36c9559 | 2009-04-03 16:42:38 +0100 | [diff] [blame] | 574 | { |
David Howells | caaef69 | 2013-05-10 19:50:26 +0100 | [diff] [blame^] | 575 | struct fscache_cookie *cookie = object->cookie; |
| 576 | |
| 577 | _enter("{OBJ%x},%d", object->debug_id, event); |
| 578 | |
| 579 | object->oob_table = fscache_osm_run_oob; |
David Howells | 36c9559 | 2009-04-03 16:42:38 +0100 | [diff] [blame] | 580 | |
| 581 | spin_lock(&object->lock); |
| 582 | |
David Howells | caaef69 | 2013-05-10 19:50:26 +0100 | [diff] [blame^] | 583 | ASSERTIF(cookie, !test_bit(FSCACHE_COOKIE_CREATING, &object->cookie->flags)); |
David Howells | 36c9559 | 2009-04-03 16:42:38 +0100 | [diff] [blame] | 584 | |
| 585 | fscache_done_parent_op(object); |
| 586 | if (object->n_in_progress == 0) { |
| 587 | if (object->n_ops > 0) { |
| 588 | ASSERTCMP(object->n_ops, >=, object->n_obj_ops); |
David Howells | 36c9559 | 2009-04-03 16:42:38 +0100 | [diff] [blame] | 589 | fscache_start_operations(object); |
| 590 | } else { |
| 591 | ASSERT(list_empty(&object->pending_ops)); |
| 592 | } |
| 593 | } |
| 594 | spin_unlock(&object->lock); |
| 595 | |
David Howells | 52bd75f | 2009-11-19 18:11:08 +0000 | [diff] [blame] | 596 | fscache_stat(&fscache_n_cop_lookup_complete); |
David Howells | 36c9559 | 2009-04-03 16:42:38 +0100 | [diff] [blame] | 597 | object->cache->ops->lookup_complete(object); |
David Howells | 52bd75f | 2009-11-19 18:11:08 +0000 | [diff] [blame] | 598 | fscache_stat_d(&fscache_n_cop_lookup_complete); |
David Howells | 36c9559 | 2009-04-03 16:42:38 +0100 | [diff] [blame] | 599 | |
| 600 | fscache_hist(fscache_obj_instantiate_histogram, object->lookup_jif); |
| 601 | fscache_stat(&fscache_n_object_avail); |
| 602 | |
| 603 | _leave(""); |
David Howells | caaef69 | 2013-05-10 19:50:26 +0100 | [diff] [blame^] | 604 | return transit_to(JUMPSTART_DEPS); |
David Howells | 36c9559 | 2009-04-03 16:42:38 +0100 | [diff] [blame] | 605 | } |
| 606 | |
| 607 | /* |
David Howells | caaef69 | 2013-05-10 19:50:26 +0100 | [diff] [blame^] | 608 | * Wake up this object's dependent objects now that we've become available. |
David Howells | 36c9559 | 2009-04-03 16:42:38 +0100 | [diff] [blame] | 609 | */ |
David Howells | caaef69 | 2013-05-10 19:50:26 +0100 | [diff] [blame^] | 610 | static const struct fscache_state *fscache_jumpstart_dependents(struct fscache_object *object, |
| 611 | int event) |
| 612 | { |
| 613 | _enter("{OBJ%x},%d", object->debug_id, event); |
| 614 | |
| 615 | if (!fscache_enqueue_dependents(object, FSCACHE_OBJECT_EV_PARENT_READY)) |
| 616 | return NO_TRANSIT; /* Not finished; requeue */ |
| 617 | return transit_to(WAIT_FOR_CMD); |
| 618 | } |
| 619 | |
| 620 | /* |
| 621 | * Handle lookup or creation failute. |
| 622 | */ |
| 623 | static const struct fscache_state *fscache_lookup_failure(struct fscache_object *object, |
| 624 | int event) |
| 625 | { |
| 626 | struct fscache_cookie *cookie; |
| 627 | bool wake_looking_up = false; |
| 628 | |
| 629 | _enter("{OBJ%x},%d", object->debug_id, event); |
| 630 | |
| 631 | object->oob_event_mask = 0; |
| 632 | |
| 633 | fscache_stat(&fscache_n_cop_lookup_complete); |
| 634 | object->cache->ops->lookup_complete(object); |
| 635 | fscache_stat_d(&fscache_n_cop_lookup_complete); |
| 636 | |
| 637 | spin_lock(&object->lock); |
| 638 | cookie = object->cookie; |
| 639 | set_bit(FSCACHE_COOKIE_UNAVAILABLE, &cookie->flags); |
| 640 | if (cookie) { |
| 641 | if (test_and_clear_bit(FSCACHE_COOKIE_LOOKING_UP, &cookie->flags)) |
| 642 | wake_looking_up = true; |
| 643 | clear_bit_unlock(FSCACHE_COOKIE_CREATING, &cookie->flags); |
| 644 | } |
| 645 | spin_unlock(&object->lock); |
| 646 | |
| 647 | if (wake_looking_up) |
| 648 | wake_up_bit(&cookie->flags, FSCACHE_COOKIE_LOOKING_UP); |
| 649 | wake_up_bit(&cookie->flags, FSCACHE_COOKIE_CREATING); |
| 650 | |
| 651 | fscache_done_parent_op(object); |
| 652 | return transit_to(KILL_OBJECT); |
| 653 | } |
| 654 | |
| 655 | /* |
| 656 | * Wait for completion of all active operations on this object and the death of |
| 657 | * all child objects of this object. |
| 658 | */ |
| 659 | static const struct fscache_state *fscache_kill_object(struct fscache_object *object, |
| 660 | int event) |
| 661 | { |
| 662 | _enter("{OBJ%x,%d,%d},%d", |
| 663 | object->debug_id, object->n_ops, object->n_children, event); |
| 664 | |
| 665 | object->oob_event_mask = 0; |
| 666 | |
| 667 | spin_lock(&object->lock); |
| 668 | clear_bit(FSCACHE_OBJECT_IS_LIVE, &object->flags); |
| 669 | spin_unlock(&object->lock); |
| 670 | |
| 671 | if (list_empty(&object->dependents) && |
| 672 | object->n_ops == 0 && |
| 673 | object->n_children == 0) |
| 674 | return object->cookie ? |
| 675 | transit_to(DETACH_FROM_COOKIE) : transit_to(DROP_OBJECT); |
| 676 | |
| 677 | spin_lock(&object->lock); |
| 678 | fscache_start_operations(object); |
| 679 | spin_unlock(&object->lock); |
| 680 | |
| 681 | if (!list_empty(&object->dependents)) |
| 682 | return transit_to(KILL_DEPENDENTS); |
| 683 | |
| 684 | return transit_to(WAIT_FOR_CLEARANCE); |
| 685 | } |
| 686 | |
| 687 | /* |
| 688 | * Kill dependent objects. |
| 689 | */ |
| 690 | static const struct fscache_state *fscache_kill_dependents(struct fscache_object *object, |
| 691 | int event) |
| 692 | { |
| 693 | _enter("{OBJ%x},%d", object->debug_id, event); |
| 694 | |
| 695 | if (!fscache_enqueue_dependents(object, FSCACHE_OBJECT_EV_KILL)) |
| 696 | return NO_TRANSIT; /* Not finished */ |
| 697 | return transit_to(WAIT_FOR_CLEARANCE); |
| 698 | } |
| 699 | |
| 700 | /* |
| 701 | * withdraw an object from active service |
| 702 | */ |
| 703 | static const struct fscache_state *fscache_detach_from_cookie(struct fscache_object *object, |
| 704 | int event) |
| 705 | { |
| 706 | struct fscache_cookie *cookie; |
| 707 | bool detached = false, awaken = false; |
| 708 | |
| 709 | _enter("{OBJ%x},%d", object->debug_id, event); |
| 710 | |
| 711 | spin_lock(&object->lock); |
| 712 | cookie = object->cookie; |
| 713 | if (cookie) { |
| 714 | /* need to get the cookie lock before the object lock, starting |
| 715 | * from the object pointer */ |
| 716 | atomic_inc(&cookie->usage); |
| 717 | spin_unlock(&object->lock); |
| 718 | |
| 719 | spin_lock(&cookie->lock); |
| 720 | spin_lock(&object->lock); |
| 721 | |
| 722 | if (object->cookie == cookie) { |
| 723 | hlist_del_init(&object->cookie_link); |
| 724 | object->cookie = NULL; |
| 725 | if (test_and_clear_bit(FSCACHE_COOKIE_INVALIDATING, |
| 726 | &cookie->flags)) |
| 727 | awaken = true; |
| 728 | detached = true; |
| 729 | } |
| 730 | spin_unlock(&cookie->lock); |
| 731 | fscache_cookie_put(cookie); |
| 732 | if (detached) |
| 733 | fscache_cookie_put(cookie); |
| 734 | } |
| 735 | |
| 736 | spin_unlock(&object->lock); |
| 737 | |
| 738 | if (awaken) |
| 739 | wake_up_bit(&cookie->flags, FSCACHE_COOKIE_INVALIDATING); |
| 740 | |
| 741 | fscache_stat(&fscache_n_object_dead); |
| 742 | _leave(""); |
| 743 | return transit_to(DROP_OBJECT); |
| 744 | } |
| 745 | |
| 746 | /* |
| 747 | * Drop an object's attachments |
| 748 | */ |
| 749 | static const struct fscache_state *fscache_drop_object(struct fscache_object *object, |
| 750 | int event) |
David Howells | 36c9559 | 2009-04-03 16:42:38 +0100 | [diff] [blame] | 751 | { |
| 752 | struct fscache_object *parent = object->parent; |
| 753 | struct fscache_cache *cache = object->cache; |
| 754 | |
David Howells | caaef69 | 2013-05-10 19:50:26 +0100 | [diff] [blame^] | 755 | _enter("{OBJ%x,%d},%d", object->debug_id, object->n_children, event); |
David Howells | 36c9559 | 2009-04-03 16:42:38 +0100 | [diff] [blame] | 756 | |
David Howells | 6897e3d | 2009-11-19 18:11:22 +0000 | [diff] [blame] | 757 | ASSERTCMP(object->cookie, ==, NULL); |
| 758 | ASSERT(hlist_unhashed(&object->cookie_link)); |
| 759 | |
David Howells | caaef69 | 2013-05-10 19:50:26 +0100 | [diff] [blame^] | 760 | /* Prevent a race with our last child, which has to signal EV_CLEARED |
| 761 | * before dropping our spinlock. |
| 762 | */ |
| 763 | spin_lock(&object->lock); |
| 764 | spin_unlock(&object->lock); |
| 765 | |
| 766 | /* Discard from the cache's collection of objects */ |
David Howells | 36c9559 | 2009-04-03 16:42:38 +0100 | [diff] [blame] | 767 | spin_lock(&cache->object_list_lock); |
| 768 | list_del_init(&object->cache_link); |
| 769 | spin_unlock(&cache->object_list_lock); |
| 770 | |
David Howells | 52bd75f | 2009-11-19 18:11:08 +0000 | [diff] [blame] | 771 | fscache_stat(&fscache_n_cop_drop_object); |
David Howells | 36c9559 | 2009-04-03 16:42:38 +0100 | [diff] [blame] | 772 | cache->ops->drop_object(object); |
David Howells | 52bd75f | 2009-11-19 18:11:08 +0000 | [diff] [blame] | 773 | fscache_stat_d(&fscache_n_cop_drop_object); |
David Howells | 36c9559 | 2009-04-03 16:42:38 +0100 | [diff] [blame] | 774 | |
David Howells | caaef69 | 2013-05-10 19:50:26 +0100 | [diff] [blame^] | 775 | /* The parent object wants to know when all it dependents have gone */ |
David Howells | 36c9559 | 2009-04-03 16:42:38 +0100 | [diff] [blame] | 776 | if (parent) { |
| 777 | _debug("release parent OBJ%x {%d}", |
| 778 | parent->debug_id, parent->n_children); |
| 779 | |
| 780 | spin_lock(&parent->lock); |
| 781 | parent->n_children--; |
| 782 | if (parent->n_children == 0) |
| 783 | fscache_raise_event(parent, FSCACHE_OBJECT_EV_CLEARED); |
| 784 | spin_unlock(&parent->lock); |
| 785 | object->parent = NULL; |
| 786 | } |
| 787 | |
Tejun Heo | 8b8edef | 2010-07-20 22:09:01 +0200 | [diff] [blame] | 788 | /* this just shifts the object release to the work processor */ |
| 789 | fscache_put_object(object); |
David Howells | caaef69 | 2013-05-10 19:50:26 +0100 | [diff] [blame^] | 790 | fscache_stat(&fscache_n_object_dead); |
David Howells | 36c9559 | 2009-04-03 16:42:38 +0100 | [diff] [blame] | 791 | |
| 792 | _leave(""); |
David Howells | caaef69 | 2013-05-10 19:50:26 +0100 | [diff] [blame^] | 793 | return transit_to(OBJECT_DEAD); |
David Howells | 36c9559 | 2009-04-03 16:42:38 +0100 | [diff] [blame] | 794 | } |
| 795 | |
| 796 | /* |
Tejun Heo | 8b8edef | 2010-07-20 22:09:01 +0200 | [diff] [blame] | 797 | * get a ref on an object |
David Howells | 36c9559 | 2009-04-03 16:42:38 +0100 | [diff] [blame] | 798 | */ |
Tejun Heo | 8b8edef | 2010-07-20 22:09:01 +0200 | [diff] [blame] | 799 | static int fscache_get_object(struct fscache_object *object) |
David Howells | 36c9559 | 2009-04-03 16:42:38 +0100 | [diff] [blame] | 800 | { |
David Howells | 52bd75f | 2009-11-19 18:11:08 +0000 | [diff] [blame] | 801 | int ret; |
David Howells | 36c9559 | 2009-04-03 16:42:38 +0100 | [diff] [blame] | 802 | |
David Howells | 52bd75f | 2009-11-19 18:11:08 +0000 | [diff] [blame] | 803 | fscache_stat(&fscache_n_cop_grab_object); |
| 804 | ret = object->cache->ops->grab_object(object) ? 0 : -EAGAIN; |
| 805 | fscache_stat_d(&fscache_n_cop_grab_object); |
| 806 | return ret; |
David Howells | 36c9559 | 2009-04-03 16:42:38 +0100 | [diff] [blame] | 807 | } |
| 808 | |
| 809 | /* |
David Howells | caaef69 | 2013-05-10 19:50:26 +0100 | [diff] [blame^] | 810 | * Discard a ref on an object |
David Howells | 36c9559 | 2009-04-03 16:42:38 +0100 | [diff] [blame] | 811 | */ |
Tejun Heo | 8b8edef | 2010-07-20 22:09:01 +0200 | [diff] [blame] | 812 | static void fscache_put_object(struct fscache_object *object) |
David Howells | 36c9559 | 2009-04-03 16:42:38 +0100 | [diff] [blame] | 813 | { |
David Howells | 52bd75f | 2009-11-19 18:11:08 +0000 | [diff] [blame] | 814 | fscache_stat(&fscache_n_cop_put_object); |
| 815 | object->cache->ops->put_object(object); |
| 816 | fscache_stat_d(&fscache_n_cop_put_object); |
David Howells | 36c9559 | 2009-04-03 16:42:38 +0100 | [diff] [blame] | 817 | } |
| 818 | |
| 819 | /* |
| 820 | * enqueue an object for metadata-type processing |
| 821 | */ |
| 822 | void fscache_enqueue_object(struct fscache_object *object) |
| 823 | { |
| 824 | _enter("{OBJ%x}", object->debug_id); |
| 825 | |
Tejun Heo | 8b8edef | 2010-07-20 22:09:01 +0200 | [diff] [blame] | 826 | if (fscache_get_object(object) >= 0) { |
| 827 | wait_queue_head_t *cong_wq = |
| 828 | &get_cpu_var(fscache_object_cong_wait); |
| 829 | |
| 830 | if (queue_work(fscache_object_wq, &object->work)) { |
| 831 | if (fscache_object_congested()) |
| 832 | wake_up(cong_wq); |
| 833 | } else |
| 834 | fscache_put_object(object); |
| 835 | |
| 836 | put_cpu_var(fscache_object_cong_wait); |
| 837 | } |
David Howells | 36c9559 | 2009-04-03 16:42:38 +0100 | [diff] [blame] | 838 | } |
| 839 | |
Tejun Heo | 8b8edef | 2010-07-20 22:09:01 +0200 | [diff] [blame] | 840 | /** |
| 841 | * fscache_object_sleep_till_congested - Sleep until object wq is congested |
David Howells | caaef69 | 2013-05-10 19:50:26 +0100 | [diff] [blame^] | 842 | * @timeoutp: Scheduler sleep timeout |
Tejun Heo | 8b8edef | 2010-07-20 22:09:01 +0200 | [diff] [blame] | 843 | * |
| 844 | * Allow an object handler to sleep until the object workqueue is congested. |
| 845 | * |
| 846 | * The caller must set up a wake up event before calling this and must have set |
| 847 | * the appropriate sleep mode (such as TASK_UNINTERRUPTIBLE) and tested its own |
| 848 | * condition before calling this function as no test is made here. |
| 849 | * |
| 850 | * %true is returned if the object wq is congested, %false otherwise. |
| 851 | */ |
| 852 | bool fscache_object_sleep_till_congested(signed long *timeoutp) |
| 853 | { |
| 854 | wait_queue_head_t *cong_wq = &__get_cpu_var(fscache_object_cong_wait); |
| 855 | DEFINE_WAIT(wait); |
| 856 | |
| 857 | if (fscache_object_congested()) |
| 858 | return true; |
| 859 | |
| 860 | add_wait_queue_exclusive(cong_wq, &wait); |
| 861 | if (!fscache_object_congested()) |
| 862 | *timeoutp = schedule_timeout(*timeoutp); |
| 863 | finish_wait(cong_wq, &wait); |
| 864 | |
| 865 | return fscache_object_congested(); |
| 866 | } |
| 867 | EXPORT_SYMBOL_GPL(fscache_object_sleep_till_congested); |
| 868 | |
David Howells | 36c9559 | 2009-04-03 16:42:38 +0100 | [diff] [blame] | 869 | /* |
David Howells | caaef69 | 2013-05-10 19:50:26 +0100 | [diff] [blame^] | 870 | * Enqueue the dependents of an object for metadata-type processing. |
| 871 | * |
| 872 | * If we don't manage to finish the list before the scheduler wants to run |
| 873 | * again then return false immediately. We return true if the list was |
| 874 | * cleared. |
David Howells | 36c9559 | 2009-04-03 16:42:38 +0100 | [diff] [blame] | 875 | */ |
David Howells | caaef69 | 2013-05-10 19:50:26 +0100 | [diff] [blame^] | 876 | static bool fscache_enqueue_dependents(struct fscache_object *object, int event) |
David Howells | 36c9559 | 2009-04-03 16:42:38 +0100 | [diff] [blame] | 877 | { |
| 878 | struct fscache_object *dep; |
David Howells | caaef69 | 2013-05-10 19:50:26 +0100 | [diff] [blame^] | 879 | bool ret = true; |
David Howells | 36c9559 | 2009-04-03 16:42:38 +0100 | [diff] [blame] | 880 | |
| 881 | _enter("{OBJ%x}", object->debug_id); |
| 882 | |
| 883 | if (list_empty(&object->dependents)) |
David Howells | caaef69 | 2013-05-10 19:50:26 +0100 | [diff] [blame^] | 884 | return true; |
David Howells | 36c9559 | 2009-04-03 16:42:38 +0100 | [diff] [blame] | 885 | |
| 886 | spin_lock(&object->lock); |
| 887 | |
| 888 | while (!list_empty(&object->dependents)) { |
| 889 | dep = list_entry(object->dependents.next, |
| 890 | struct fscache_object, dep_link); |
| 891 | list_del_init(&dep->dep_link); |
| 892 | |
David Howells | caaef69 | 2013-05-10 19:50:26 +0100 | [diff] [blame^] | 893 | fscache_raise_event(dep, event); |
Tejun Heo | 8b8edef | 2010-07-20 22:09:01 +0200 | [diff] [blame] | 894 | fscache_put_object(dep); |
David Howells | 36c9559 | 2009-04-03 16:42:38 +0100 | [diff] [blame] | 895 | |
David Howells | caaef69 | 2013-05-10 19:50:26 +0100 | [diff] [blame^] | 896 | if (!list_empty(&object->dependents) && need_resched()) { |
| 897 | ret = false; |
| 898 | break; |
| 899 | } |
David Howells | 36c9559 | 2009-04-03 16:42:38 +0100 | [diff] [blame] | 900 | } |
| 901 | |
| 902 | spin_unlock(&object->lock); |
David Howells | caaef69 | 2013-05-10 19:50:26 +0100 | [diff] [blame^] | 903 | return ret; |
David Howells | 36c9559 | 2009-04-03 16:42:38 +0100 | [diff] [blame] | 904 | } |
| 905 | |
| 906 | /* |
| 907 | * remove an object from whatever queue it's waiting on |
David Howells | 36c9559 | 2009-04-03 16:42:38 +0100 | [diff] [blame] | 908 | */ |
David Howells | caaef69 | 2013-05-10 19:50:26 +0100 | [diff] [blame^] | 909 | static void fscache_dequeue_object(struct fscache_object *object) |
David Howells | 36c9559 | 2009-04-03 16:42:38 +0100 | [diff] [blame] | 910 | { |
| 911 | _enter("{OBJ%x}", object->debug_id); |
| 912 | |
| 913 | if (!list_empty(&object->dep_link)) { |
| 914 | spin_lock(&object->parent->lock); |
| 915 | list_del_init(&object->dep_link); |
| 916 | spin_unlock(&object->parent->lock); |
| 917 | } |
| 918 | |
| 919 | _leave(""); |
| 920 | } |
| 921 | |
| 922 | /** |
| 923 | * fscache_check_aux - Ask the netfs whether an object on disk is still valid |
| 924 | * @object: The object to ask about |
| 925 | * @data: The auxiliary data for the object |
| 926 | * @datalen: The size of the auxiliary data |
| 927 | * |
| 928 | * This function consults the netfs about the coherency state of an object |
| 929 | */ |
| 930 | enum fscache_checkaux fscache_check_aux(struct fscache_object *object, |
| 931 | const void *data, uint16_t datalen) |
| 932 | { |
| 933 | enum fscache_checkaux result; |
| 934 | |
| 935 | if (!object->cookie->def->check_aux) { |
| 936 | fscache_stat(&fscache_n_checkaux_none); |
| 937 | return FSCACHE_CHECKAUX_OKAY; |
| 938 | } |
| 939 | |
| 940 | result = object->cookie->def->check_aux(object->cookie->netfs_data, |
| 941 | data, datalen); |
| 942 | switch (result) { |
| 943 | /* entry okay as is */ |
| 944 | case FSCACHE_CHECKAUX_OKAY: |
| 945 | fscache_stat(&fscache_n_checkaux_okay); |
| 946 | break; |
| 947 | |
| 948 | /* entry requires update */ |
| 949 | case FSCACHE_CHECKAUX_NEEDS_UPDATE: |
| 950 | fscache_stat(&fscache_n_checkaux_update); |
| 951 | break; |
| 952 | |
| 953 | /* entry requires deletion */ |
| 954 | case FSCACHE_CHECKAUX_OBSOLETE: |
| 955 | fscache_stat(&fscache_n_checkaux_obsolete); |
| 956 | break; |
| 957 | |
| 958 | default: |
| 959 | BUG(); |
| 960 | } |
| 961 | |
| 962 | return result; |
| 963 | } |
| 964 | EXPORT_SYMBOL(fscache_check_aux); |
David Howells | ef778e7 | 2012-12-20 21:52:36 +0000 | [diff] [blame] | 965 | |
| 966 | /* |
| 967 | * Asynchronously invalidate an object. |
| 968 | */ |
David Howells | caaef69 | 2013-05-10 19:50:26 +0100 | [diff] [blame^] | 969 | static const struct fscache_state *_fscache_invalidate_object(struct fscache_object *object, |
| 970 | int event) |
David Howells | ef778e7 | 2012-12-20 21:52:36 +0000 | [diff] [blame] | 971 | { |
| 972 | struct fscache_operation *op; |
| 973 | struct fscache_cookie *cookie = object->cookie; |
| 974 | |
David Howells | caaef69 | 2013-05-10 19:50:26 +0100 | [diff] [blame^] | 975 | _enter("{OBJ%x},%d", object->debug_id, event); |
| 976 | |
David Howells | ef778e7 | 2012-12-20 21:52:36 +0000 | [diff] [blame] | 977 | |
| 978 | /* Reject any new read/write ops and abort any that are pending. */ |
| 979 | fscache_invalidate_writes(cookie); |
| 980 | clear_bit(FSCACHE_OBJECT_PENDING_WRITE, &object->flags); |
| 981 | fscache_cancel_all_ops(object); |
| 982 | |
| 983 | /* Now we have to wait for in-progress reads and writes */ |
| 984 | op = kzalloc(sizeof(*op), GFP_KERNEL); |
| 985 | if (!op) { |
David Howells | caaef69 | 2013-05-10 19:50:26 +0100 | [diff] [blame^] | 986 | clear_bit(FSCACHE_OBJECT_IS_LIVE, &object->flags); |
David Howells | ef778e7 | 2012-12-20 21:52:36 +0000 | [diff] [blame] | 987 | _leave(" [ENOMEM]"); |
David Howells | caaef69 | 2013-05-10 19:50:26 +0100 | [diff] [blame^] | 988 | return transit_to(KILL_OBJECT); |
David Howells | ef778e7 | 2012-12-20 21:52:36 +0000 | [diff] [blame] | 989 | } |
| 990 | |
| 991 | fscache_operation_init(op, object->cache->ops->invalidate_object, NULL); |
| 992 | op->flags = FSCACHE_OP_ASYNC | (1 << FSCACHE_OP_EXCLUSIVE); |
| 993 | |
| 994 | spin_lock(&cookie->lock); |
| 995 | if (fscache_submit_exclusive_op(object, op) < 0) |
David Howells | 8d76349 | 2012-12-05 13:34:48 +0000 | [diff] [blame] | 996 | goto submit_op_failed; |
David Howells | ef778e7 | 2012-12-20 21:52:36 +0000 | [diff] [blame] | 997 | spin_unlock(&cookie->lock); |
| 998 | fscache_put_operation(op); |
| 999 | |
| 1000 | /* Once we've completed the invalidation, we know there will be no data |
| 1001 | * stored in the cache and thus we can reinstate the data-check-skip |
| 1002 | * optimisation. |
| 1003 | */ |
| 1004 | set_bit(FSCACHE_COOKIE_NO_DATA_YET, &cookie->flags); |
| 1005 | |
| 1006 | /* We can allow read and write requests to come in once again. They'll |
| 1007 | * queue up behind our exclusive invalidation operation. |
| 1008 | */ |
David Howells | caaef69 | 2013-05-10 19:50:26 +0100 | [diff] [blame^] | 1009 | if (test_and_clear_bit(FSCACHE_COOKIE_INVALIDATING, &cookie->flags)) |
| 1010 | wake_up_bit(&cookie->flags, FSCACHE_COOKIE_INVALIDATING); |
| 1011 | _leave(" [ok]"); |
| 1012 | return transit_to(UPDATE_OBJECT); |
David Howells | 8d76349 | 2012-12-05 13:34:48 +0000 | [diff] [blame] | 1013 | |
| 1014 | submit_op_failed: |
David Howells | caaef69 | 2013-05-10 19:50:26 +0100 | [diff] [blame^] | 1015 | clear_bit(FSCACHE_OBJECT_IS_LIVE, &object->flags); |
David Howells | 8d76349 | 2012-12-05 13:34:48 +0000 | [diff] [blame] | 1016 | spin_unlock(&cookie->lock); |
| 1017 | kfree(op); |
David Howells | 8d76349 | 2012-12-05 13:34:48 +0000 | [diff] [blame] | 1018 | _leave(" [EIO]"); |
David Howells | caaef69 | 2013-05-10 19:50:26 +0100 | [diff] [blame^] | 1019 | return transit_to(KILL_OBJECT); |
| 1020 | } |
| 1021 | |
| 1022 | static const struct fscache_state *fscache_invalidate_object(struct fscache_object *object, |
| 1023 | int event) |
| 1024 | { |
| 1025 | const struct fscache_state *s; |
| 1026 | |
| 1027 | fscache_stat(&fscache_n_invalidates_run); |
| 1028 | fscache_stat(&fscache_n_cop_invalidate_object); |
| 1029 | s = _fscache_invalidate_object(object, event); |
| 1030 | fscache_stat_d(&fscache_n_cop_invalidate_object); |
| 1031 | return s; |
| 1032 | } |
| 1033 | |
| 1034 | /* |
| 1035 | * Asynchronously update an object. |
| 1036 | */ |
| 1037 | static const struct fscache_state *fscache_update_object(struct fscache_object *object, |
| 1038 | int event) |
| 1039 | { |
| 1040 | _enter("{OBJ%x},%d", object->debug_id, event); |
| 1041 | |
| 1042 | fscache_stat(&fscache_n_updates_run); |
| 1043 | fscache_stat(&fscache_n_cop_update_object); |
| 1044 | object->cache->ops->update_object(object); |
| 1045 | fscache_stat_d(&fscache_n_cop_update_object); |
| 1046 | |
| 1047 | _leave(""); |
| 1048 | return transit_to(WAIT_FOR_CMD); |
David Howells | ef778e7 | 2012-12-20 21:52:36 +0000 | [diff] [blame] | 1049 | } |