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Commit | Line | Data |
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1da177e4 | 1 | /* |
7b718769 | 2 | * Copyright (c) 2000-2002,2005 Silicon Graphics, Inc. |
c7e8f268 | 3 | * Copyright (c) 2008 Dave Chinner |
7b718769 | 4 | * All Rights Reserved. |
1da177e4 | 5 | * |
7b718769 NS |
6 | * This program is free software; you can redistribute it and/or |
7 | * modify it under the terms of the GNU General Public License as | |
1da177e4 LT |
8 | * published by the Free Software Foundation. |
9 | * | |
7b718769 NS |
10 | * This program is distributed in the hope that it would be useful, |
11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
13 | * GNU General Public License for more details. | |
1da177e4 | 14 | * |
7b718769 NS |
15 | * You should have received a copy of the GNU General Public License |
16 | * along with this program; if not, write the Free Software Foundation, | |
17 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA | |
1da177e4 | 18 | */ |
1da177e4 | 19 | #include "xfs.h" |
a844f451 | 20 | #include "xfs_fs.h" |
1da177e4 | 21 | #include "xfs_types.h" |
1da177e4 | 22 | #include "xfs_log.h" |
a844f451 | 23 | #include "xfs_inum.h" |
1da177e4 LT |
24 | #include "xfs_trans.h" |
25 | #include "xfs_sb.h" | |
da353b0d | 26 | #include "xfs_ag.h" |
1da177e4 LT |
27 | #include "xfs_mount.h" |
28 | #include "xfs_trans_priv.h" | |
29 | #include "xfs_error.h" | |
30 | ||
0bf6a5bd DC |
31 | struct workqueue_struct *xfs_ail_wq; /* AIL workqueue */ |
32 | ||
1da177e4 | 33 | #ifdef DEBUG |
cd4a3c50 DC |
34 | /* |
35 | * Check that the list is sorted as it should be. | |
36 | */ | |
37 | STATIC void | |
38 | xfs_ail_check( | |
39 | struct xfs_ail *ailp, | |
40 | xfs_log_item_t *lip) | |
41 | { | |
42 | xfs_log_item_t *prev_lip; | |
43 | ||
44 | if (list_empty(&ailp->xa_ail)) | |
45 | return; | |
46 | ||
47 | /* | |
48 | * Check the next and previous entries are valid. | |
49 | */ | |
50 | ASSERT((lip->li_flags & XFS_LI_IN_AIL) != 0); | |
51 | prev_lip = list_entry(lip->li_ail.prev, xfs_log_item_t, li_ail); | |
52 | if (&prev_lip->li_ail != &ailp->xa_ail) | |
53 | ASSERT(XFS_LSN_CMP(prev_lip->li_lsn, lip->li_lsn) <= 0); | |
54 | ||
55 | prev_lip = list_entry(lip->li_ail.next, xfs_log_item_t, li_ail); | |
56 | if (&prev_lip->li_ail != &ailp->xa_ail) | |
57 | ASSERT(XFS_LSN_CMP(prev_lip->li_lsn, lip->li_lsn) >= 0); | |
58 | ||
59 | ||
60 | #ifdef XFS_TRANS_DEBUG | |
61 | /* | |
62 | * Walk the list checking lsn ordering, and that every entry has the | |
63 | * XFS_LI_IN_AIL flag set. This is really expensive, so only do it | |
64 | * when specifically debugging the transaction subsystem. | |
65 | */ | |
66 | prev_lip = list_entry(&ailp->xa_ail, xfs_log_item_t, li_ail); | |
67 | list_for_each_entry(lip, &ailp->xa_ail, li_ail) { | |
68 | if (&prev_lip->li_ail != &ailp->xa_ail) | |
69 | ASSERT(XFS_LSN_CMP(prev_lip->li_lsn, lip->li_lsn) <= 0); | |
70 | ASSERT((lip->li_flags & XFS_LI_IN_AIL) != 0); | |
71 | prev_lip = lip; | |
72 | } | |
73 | #endif /* XFS_TRANS_DEBUG */ | |
74 | } | |
75 | #else /* !DEBUG */ | |
de08dbc1 | 76 | #define xfs_ail_check(a,l) |
1da177e4 LT |
77 | #endif /* DEBUG */ |
78 | ||
cd4a3c50 DC |
79 | /* |
80 | * Return a pointer to the first item in the AIL. If the AIL is empty, then | |
81 | * return NULL. | |
82 | */ | |
83 | static xfs_log_item_t * | |
84 | xfs_ail_min( | |
85 | struct xfs_ail *ailp) | |
86 | { | |
87 | if (list_empty(&ailp->xa_ail)) | |
88 | return NULL; | |
89 | ||
90 | return list_first_entry(&ailp->xa_ail, xfs_log_item_t, li_ail); | |
91 | } | |
92 | ||
fd074841 DC |
93 | /* |
94 | * Return a pointer to the last item in the AIL. If the AIL is empty, then | |
95 | * return NULL. | |
96 | */ | |
97 | static xfs_log_item_t * | |
98 | xfs_ail_max( | |
99 | struct xfs_ail *ailp) | |
100 | { | |
101 | if (list_empty(&ailp->xa_ail)) | |
102 | return NULL; | |
103 | ||
104 | return list_entry(ailp->xa_ail.prev, xfs_log_item_t, li_ail); | |
105 | } | |
106 | ||
cd4a3c50 DC |
107 | /* |
108 | * Return a pointer to the item which follows the given item in the AIL. If | |
109 | * the given item is the last item in the list, then return NULL. | |
110 | */ | |
111 | static xfs_log_item_t * | |
112 | xfs_ail_next( | |
113 | struct xfs_ail *ailp, | |
114 | xfs_log_item_t *lip) | |
115 | { | |
116 | if (lip->li_ail.next == &ailp->xa_ail) | |
117 | return NULL; | |
118 | ||
119 | return list_first_entry(&lip->li_ail, xfs_log_item_t, li_ail); | |
120 | } | |
1da177e4 LT |
121 | |
122 | /* | |
cd4a3c50 DC |
123 | * This is called by the log manager code to determine the LSN of the tail of |
124 | * the log. This is exactly the LSN of the first item in the AIL. If the AIL | |
125 | * is empty, then this function returns 0. | |
1da177e4 | 126 | * |
cd4a3c50 DC |
127 | * We need the AIL lock in order to get a coherent read of the lsn of the last |
128 | * item in the AIL. | |
1da177e4 LT |
129 | */ |
130 | xfs_lsn_t | |
fd074841 | 131 | xfs_ail_min_lsn( |
5b00f14f | 132 | struct xfs_ail *ailp) |
1da177e4 | 133 | { |
cd4a3c50 | 134 | xfs_lsn_t lsn = 0; |
1da177e4 | 135 | xfs_log_item_t *lip; |
1da177e4 | 136 | |
c7e8f268 | 137 | spin_lock(&ailp->xa_lock); |
5b00f14f | 138 | lip = xfs_ail_min(ailp); |
cd4a3c50 | 139 | if (lip) |
1da177e4 | 140 | lsn = lip->li_lsn; |
c7e8f268 | 141 | spin_unlock(&ailp->xa_lock); |
1da177e4 LT |
142 | |
143 | return lsn; | |
144 | } | |
145 | ||
fd074841 DC |
146 | /* |
147 | * Return the maximum lsn held in the AIL, or zero if the AIL is empty. | |
148 | */ | |
149 | static xfs_lsn_t | |
150 | xfs_ail_max_lsn( | |
151 | struct xfs_ail *ailp) | |
152 | { | |
153 | xfs_lsn_t lsn = 0; | |
154 | xfs_log_item_t *lip; | |
155 | ||
156 | spin_lock(&ailp->xa_lock); | |
157 | lip = xfs_ail_max(ailp); | |
158 | if (lip) | |
159 | lsn = lip->li_lsn; | |
160 | spin_unlock(&ailp->xa_lock); | |
161 | ||
162 | return lsn; | |
163 | } | |
164 | ||
27d8d5fe DC |
165 | /* |
166 | * AIL traversal cursor initialisation. | |
167 | * | |
168 | * The cursor keeps track of where our current traversal is up | |
169 | * to by tracking the next ƣtem in the list for us. However, for | |
170 | * this to be safe, removing an object from the AIL needs to invalidate | |
171 | * any cursor that points to it. hence the traversal cursor needs to | |
172 | * be linked to the struct xfs_ail so that deletion can search all the | |
173 | * active cursors for invalidation. | |
174 | * | |
175 | * We don't link the push cursor because it is embedded in the struct | |
176 | * xfs_ail and hence easily findable. | |
177 | */ | |
5b00f14f | 178 | STATIC void |
27d8d5fe DC |
179 | xfs_trans_ail_cursor_init( |
180 | struct xfs_ail *ailp, | |
181 | struct xfs_ail_cursor *cur) | |
182 | { | |
183 | cur->item = NULL; | |
184 | if (cur == &ailp->xa_cursors) | |
185 | return; | |
186 | ||
187 | cur->next = ailp->xa_cursors.next; | |
188 | ailp->xa_cursors.next = cur; | |
189 | } | |
190 | ||
27d8d5fe DC |
191 | /* |
192 | * Get the next item in the traversal and advance the cursor. | |
193 | * If the cursor was invalidated (inidicated by a lip of 1), | |
194 | * restart the traversal. | |
195 | */ | |
5b00f14f | 196 | struct xfs_log_item * |
27d8d5fe DC |
197 | xfs_trans_ail_cursor_next( |
198 | struct xfs_ail *ailp, | |
199 | struct xfs_ail_cursor *cur) | |
200 | { | |
201 | struct xfs_log_item *lip = cur->item; | |
202 | ||
203 | if ((__psint_t)lip & 1) | |
204 | lip = xfs_ail_min(ailp); | |
16b59029 DC |
205 | if (lip) |
206 | cur->item = xfs_ail_next(ailp, lip); | |
27d8d5fe DC |
207 | return lip; |
208 | } | |
209 | ||
27d8d5fe DC |
210 | /* |
211 | * Now that the traversal is complete, we need to remove the cursor | |
212 | * from the list of traversing cursors. Avoid removing the embedded | |
9da096fd | 213 | * push cursor, but use the fact it is always present to make the |
27d8d5fe DC |
214 | * list deletion simple. |
215 | */ | |
216 | void | |
217 | xfs_trans_ail_cursor_done( | |
218 | struct xfs_ail *ailp, | |
219 | struct xfs_ail_cursor *done) | |
220 | { | |
221 | struct xfs_ail_cursor *prev = NULL; | |
222 | struct xfs_ail_cursor *cur; | |
223 | ||
224 | done->item = NULL; | |
225 | if (done == &ailp->xa_cursors) | |
226 | return; | |
227 | prev = &ailp->xa_cursors; | |
228 | for (cur = prev->next; cur; prev = cur, cur = prev->next) { | |
229 | if (cur == done) { | |
230 | prev->next = cur->next; | |
231 | break; | |
232 | } | |
233 | } | |
234 | ASSERT(cur); | |
235 | } | |
236 | ||
5b00f14f DC |
237 | /* |
238 | * Invalidate any cursor that is pointing to this item. This is | |
239 | * called when an item is removed from the AIL. Any cursor pointing | |
240 | * to this object is now invalid and the traversal needs to be | |
241 | * terminated so it doesn't reference a freed object. We set the | |
242 | * cursor item to a value of 1 so we can distinguish between an | |
243 | * invalidation and the end of the list when getting the next item | |
244 | * from the cursor. | |
245 | */ | |
246 | STATIC void | |
247 | xfs_trans_ail_cursor_clear( | |
248 | struct xfs_ail *ailp, | |
249 | struct xfs_log_item *lip) | |
250 | { | |
251 | struct xfs_ail_cursor *cur; | |
252 | ||
253 | /* need to search all cursors */ | |
254 | for (cur = &ailp->xa_cursors; cur; cur = cur->next) { | |
255 | if (cur->item == lip) | |
256 | cur->item = (struct xfs_log_item *) | |
257 | ((__psint_t)cur->item | 1); | |
258 | } | |
259 | } | |
260 | ||
249a8c11 | 261 | /* |
16b59029 DC |
262 | * Find the first item in the AIL with the given @lsn by searching in ascending |
263 | * LSN order and initialise the cursor to point to the next item for a | |
264 | * ascending traversal. Pass a @lsn of zero to initialise the cursor to the | |
265 | * first item in the AIL. Returns NULL if the list is empty. | |
249a8c11 | 266 | */ |
5b00f14f DC |
267 | xfs_log_item_t * |
268 | xfs_trans_ail_cursor_first( | |
27d8d5fe DC |
269 | struct xfs_ail *ailp, |
270 | struct xfs_ail_cursor *cur, | |
271 | xfs_lsn_t lsn) | |
249a8c11 | 272 | { |
27d8d5fe | 273 | xfs_log_item_t *lip; |
249a8c11 | 274 | |
5b00f14f | 275 | xfs_trans_ail_cursor_init(ailp, cur); |
16b59029 DC |
276 | |
277 | if (lsn == 0) { | |
278 | lip = xfs_ail_min(ailp); | |
5b00f14f | 279 | goto out; |
16b59029 | 280 | } |
249a8c11 | 281 | |
27d8d5fe | 282 | list_for_each_entry(lip, &ailp->xa_ail, li_ail) { |
5b00f14f | 283 | if (XFS_LSN_CMP(lip->li_lsn, lsn) >= 0) |
7ee49acf | 284 | goto out; |
535f6b37 | 285 | } |
16b59029 DC |
286 | return NULL; |
287 | ||
5b00f14f | 288 | out: |
16b59029 DC |
289 | if (lip) |
290 | cur->item = xfs_ail_next(ailp, lip); | |
5b00f14f | 291 | return lip; |
249a8c11 DC |
292 | } |
293 | ||
1d8c95a3 DC |
294 | static struct xfs_log_item * |
295 | __xfs_trans_ail_cursor_last( | |
296 | struct xfs_ail *ailp, | |
297 | xfs_lsn_t lsn) | |
298 | { | |
299 | xfs_log_item_t *lip; | |
300 | ||
301 | list_for_each_entry_reverse(lip, &ailp->xa_ail, li_ail) { | |
302 | if (XFS_LSN_CMP(lip->li_lsn, lsn) <= 0) | |
303 | return lip; | |
304 | } | |
305 | return NULL; | |
306 | } | |
307 | ||
308 | /* | |
16b59029 DC |
309 | * Find the last item in the AIL with the given @lsn by searching in descending |
310 | * LSN order and initialise the cursor to point to that item. If there is no | |
311 | * item with the value of @lsn, then it sets the cursor to the last item with an | |
312 | * LSN lower than @lsn. Returns NULL if the list is empty. | |
1d8c95a3 DC |
313 | */ |
314 | struct xfs_log_item * | |
315 | xfs_trans_ail_cursor_last( | |
316 | struct xfs_ail *ailp, | |
317 | struct xfs_ail_cursor *cur, | |
318 | xfs_lsn_t lsn) | |
319 | { | |
320 | xfs_trans_ail_cursor_init(ailp, cur); | |
321 | cur->item = __xfs_trans_ail_cursor_last(ailp, lsn); | |
322 | return cur->item; | |
323 | } | |
324 | ||
325 | /* | |
16b59029 | 326 | * Splice the log item list into the AIL at the given LSN. We splice to the |
1d8c95a3 DC |
327 | * tail of the given LSN to maintain insert order for push traversals. The |
328 | * cursor is optional, allowing repeated updates to the same LSN to avoid | |
329 | * repeated traversals. | |
cd4a3c50 DC |
330 | */ |
331 | static void | |
332 | xfs_ail_splice( | |
1d8c95a3 DC |
333 | struct xfs_ail *ailp, |
334 | struct xfs_ail_cursor *cur, | |
335 | struct list_head *list, | |
336 | xfs_lsn_t lsn) | |
cd4a3c50 | 337 | { |
1d8c95a3 DC |
338 | struct xfs_log_item *lip = cur ? cur->item : NULL; |
339 | struct xfs_log_item *next_lip; | |
cd4a3c50 | 340 | |
1d8c95a3 DC |
341 | /* |
342 | * Get a new cursor if we don't have a placeholder or the existing one | |
343 | * has been invalidated. | |
344 | */ | |
345 | if (!lip || (__psint_t)lip & 1) { | |
346 | lip = __xfs_trans_ail_cursor_last(ailp, lsn); | |
347 | ||
348 | if (!lip) { | |
349 | /* The list is empty, so just splice and return. */ | |
350 | if (cur) | |
351 | cur->item = NULL; | |
352 | list_splice(list, &ailp->xa_ail); | |
353 | return; | |
354 | } | |
cd4a3c50 DC |
355 | } |
356 | ||
1d8c95a3 DC |
357 | /* |
358 | * Our cursor points to the item we want to insert _after_, so we have | |
359 | * to update the cursor to point to the end of the list we are splicing | |
360 | * in so that it points to the correct location for the next splice. | |
361 | * i.e. before the splice | |
362 | * | |
363 | * lsn -> lsn -> lsn + x -> lsn + x ... | |
364 | * ^ | |
365 | * | cursor points here | |
366 | * | |
367 | * After the splice we have: | |
368 | * | |
369 | * lsn -> lsn -> lsn -> lsn -> .... -> lsn -> lsn + x -> lsn + x ... | |
370 | * ^ ^ | |
371 | * | cursor points here | needs to move here | |
372 | * | |
373 | * So we set the cursor to the last item in the list to be spliced | |
374 | * before we execute the splice, resulting in the cursor pointing to | |
375 | * the correct item after the splice occurs. | |
376 | */ | |
377 | if (cur) { | |
378 | next_lip = list_entry(list->prev, struct xfs_log_item, li_ail); | |
379 | cur->item = next_lip; | |
cd4a3c50 | 380 | } |
1d8c95a3 | 381 | list_splice(list, &lip->li_ail); |
cd4a3c50 DC |
382 | } |
383 | ||
384 | /* | |
385 | * Delete the given item from the AIL. Return a pointer to the item. | |
386 | */ | |
387 | static void | |
388 | xfs_ail_delete( | |
389 | struct xfs_ail *ailp, | |
390 | xfs_log_item_t *lip) | |
391 | { | |
392 | xfs_ail_check(ailp, lip); | |
393 | list_del(&lip->li_ail); | |
394 | xfs_trans_ail_cursor_clear(ailp, lip); | |
395 | } | |
396 | ||
249a8c11 | 397 | /* |
0bf6a5bd DC |
398 | * xfs_ail_worker does the work of pushing on the AIL. It will requeue itself |
399 | * to run at a later time if there is more work to do to complete the push. | |
249a8c11 | 400 | */ |
0bf6a5bd DC |
401 | STATIC void |
402 | xfs_ail_worker( | |
9e7004e7 | 403 | struct work_struct *work) |
249a8c11 | 404 | { |
9e7004e7 | 405 | struct xfs_ail *ailp = container_of(to_delayed_work(work), |
0bf6a5bd | 406 | struct xfs_ail, xa_work); |
9e7004e7 | 407 | xfs_mount_t *mp = ailp->xa_mount; |
27d8d5fe | 408 | struct xfs_ail_cursor *cur = &ailp->xa_cursors; |
9e7004e7 DC |
409 | xfs_log_item_t *lip; |
410 | xfs_lsn_t lsn; | |
fe0da767 | 411 | xfs_lsn_t target; |
9e7004e7 DC |
412 | long tout = 10; |
413 | int flush_log = 0; | |
414 | int stuck = 0; | |
415 | int count = 0; | |
416 | int push_xfsbufd = 0; | |
1da177e4 | 417 | |
c7e8f268 | 418 | spin_lock(&ailp->xa_lock); |
fe0da767 | 419 | target = ailp->xa_target; |
27d8d5fe | 420 | xfs_trans_ail_cursor_init(ailp, cur); |
0bf6a5bd | 421 | lip = xfs_trans_ail_cursor_first(ailp, cur, ailp->xa_last_pushed_lsn); |
249a8c11 | 422 | if (!lip || XFS_FORCED_SHUTDOWN(mp)) { |
1da177e4 | 423 | /* |
249a8c11 | 424 | * AIL is empty or our push has reached the end. |
1da177e4 | 425 | */ |
27d8d5fe | 426 | xfs_trans_ail_cursor_done(ailp, cur); |
c7e8f268 | 427 | spin_unlock(&ailp->xa_lock); |
9e7004e7 | 428 | goto out_done; |
1da177e4 LT |
429 | } |
430 | ||
431 | XFS_STATS_INC(xs_push_ail); | |
432 | ||
433 | /* | |
434 | * While the item we are looking at is below the given threshold | |
249a8c11 | 435 | * try to flush it out. We'd like not to stop until we've at least |
1da177e4 | 436 | * tried to push on everything in the AIL with an LSN less than |
249a8c11 DC |
437 | * the given threshold. |
438 | * | |
439 | * However, we will stop after a certain number of pushes and wait | |
440 | * for a reduced timeout to fire before pushing further. This | |
441 | * prevents use from spinning when we can't do anything or there is | |
442 | * lots of contention on the AIL lists. | |
1da177e4 | 443 | */ |
249a8c11 | 444 | lsn = lip->li_lsn; |
50e86686 | 445 | while ((XFS_LSN_CMP(lip->li_lsn, target) <= 0)) { |
249a8c11 | 446 | int lock_result; |
1da177e4 | 447 | /* |
249a8c11 DC |
448 | * If we can lock the item without sleeping, unlock the AIL |
449 | * lock and flush the item. Then re-grab the AIL lock so we | |
450 | * can look for the next item on the AIL. List changes are | |
451 | * handled by the AIL lookup functions internally | |
1da177e4 | 452 | * |
249a8c11 DC |
453 | * If we can't lock the item, either its holder will flush it |
454 | * or it is already being flushed or it is being relogged. In | |
455 | * any of these case it is being taken care of and we can just | |
456 | * skip to the next item in the list. | |
1da177e4 LT |
457 | */ |
458 | lock_result = IOP_TRYLOCK(lip); | |
c7e8f268 | 459 | spin_unlock(&ailp->xa_lock); |
1da177e4 | 460 | switch (lock_result) { |
249a8c11 | 461 | case XFS_ITEM_SUCCESS: |
1da177e4 LT |
462 | XFS_STATS_INC(xs_push_ail_success); |
463 | IOP_PUSH(lip); | |
0bf6a5bd | 464 | ailp->xa_last_pushed_lsn = lsn; |
1da177e4 LT |
465 | break; |
466 | ||
249a8c11 | 467 | case XFS_ITEM_PUSHBUF: |
1da177e4 | 468 | XFS_STATS_INC(xs_push_ail_pushbuf); |
1da177e4 | 469 | IOP_PUSHBUF(lip); |
0bf6a5bd | 470 | ailp->xa_last_pushed_lsn = lsn; |
d808f617 | 471 | push_xfsbufd = 1; |
1da177e4 LT |
472 | break; |
473 | ||
249a8c11 | 474 | case XFS_ITEM_PINNED: |
1da177e4 | 475 | XFS_STATS_INC(xs_push_ail_pinned); |
249a8c11 | 476 | stuck++; |
1da177e4 LT |
477 | flush_log = 1; |
478 | break; | |
479 | ||
249a8c11 | 480 | case XFS_ITEM_LOCKED: |
1da177e4 | 481 | XFS_STATS_INC(xs_push_ail_locked); |
0bf6a5bd | 482 | ailp->xa_last_pushed_lsn = lsn; |
249a8c11 | 483 | stuck++; |
1da177e4 LT |
484 | break; |
485 | ||
249a8c11 | 486 | default: |
1da177e4 LT |
487 | ASSERT(0); |
488 | break; | |
489 | } | |
490 | ||
c7e8f268 | 491 | spin_lock(&ailp->xa_lock); |
249a8c11 DC |
492 | /* should we bother continuing? */ |
493 | if (XFS_FORCED_SHUTDOWN(mp)) | |
1da177e4 | 494 | break; |
249a8c11 DC |
495 | ASSERT(mp->m_log); |
496 | ||
497 | count++; | |
1da177e4 | 498 | |
249a8c11 DC |
499 | /* |
500 | * Are there too many items we can't do anything with? | |
501 | * If we we are skipping too many items because we can't flush | |
502 | * them or they are already being flushed, we back off and | |
503 | * given them time to complete whatever operation is being | |
504 | * done. i.e. remove pressure from the AIL while we can't make | |
505 | * progress so traversals don't slow down further inserts and | |
506 | * removals to/from the AIL. | |
507 | * | |
508 | * The value of 100 is an arbitrary magic number based on | |
509 | * observation. | |
510 | */ | |
511 | if (stuck > 100) | |
512 | break; | |
513 | ||
27d8d5fe | 514 | lip = xfs_trans_ail_cursor_next(ailp, cur); |
249a8c11 DC |
515 | if (lip == NULL) |
516 | break; | |
249a8c11 | 517 | lsn = lip->li_lsn; |
1da177e4 | 518 | } |
27d8d5fe | 519 | xfs_trans_ail_cursor_done(ailp, cur); |
c7e8f268 | 520 | spin_unlock(&ailp->xa_lock); |
1da177e4 LT |
521 | |
522 | if (flush_log) { | |
523 | /* | |
524 | * If something we need to push out was pinned, then | |
525 | * push out the log so it will become unpinned and | |
526 | * move forward in the AIL. | |
527 | */ | |
1da177e4 | 528 | XFS_STATS_INC(xs_push_ail_flush); |
a14a348b | 529 | xfs_log_force(mp, 0); |
1da177e4 LT |
530 | } |
531 | ||
d808f617 DC |
532 | if (push_xfsbufd) { |
533 | /* we've got delayed write buffers to flush */ | |
534 | wake_up_process(mp->m_ddev_targp->bt_task); | |
535 | } | |
536 | ||
0bf6a5bd | 537 | /* assume we have more work to do in a short while */ |
9e7004e7 | 538 | out_done: |
92d9cd10 DC |
539 | if (!count) { |
540 | /* We're past our target or empty, so idle */ | |
0bf6a5bd DC |
541 | ailp->xa_last_pushed_lsn = 0; |
542 | ||
543 | /* | |
7ac95657 DC |
544 | * We clear the XFS_AIL_PUSHING_BIT first before checking |
545 | * whether the target has changed. If the target has changed, | |
546 | * this pushes the requeue race directly onto the result of the | |
547 | * atomic test/set bit, so we are guaranteed that either the | |
548 | * the pusher that changed the target or ourselves will requeue | |
549 | * the work (but not both). | |
0bf6a5bd | 550 | */ |
7ac95657 | 551 | clear_bit(XFS_AIL_PUSHING_BIT, &ailp->xa_flags); |
0bf6a5bd | 552 | smp_rmb(); |
7ac95657 DC |
553 | if (XFS_LSN_CMP(ailp->xa_target, target) == 0 || |
554 | test_and_set_bit(XFS_AIL_PUSHING_BIT, &ailp->xa_flags)) | |
0bf6a5bd | 555 | return; |
7ac95657 | 556 | |
0bf6a5bd | 557 | tout = 50; |
92d9cd10 DC |
558 | } else if (XFS_LSN_CMP(lsn, target) >= 0) { |
559 | /* | |
560 | * We reached the target so wait a bit longer for I/O to | |
561 | * complete and remove pushed items from the AIL before we | |
562 | * start the next scan from the start of the AIL. | |
563 | */ | |
453eac8a | 564 | tout = 50; |
0bf6a5bd | 565 | ailp->xa_last_pushed_lsn = 0; |
27d8d5fe | 566 | } else if ((stuck * 100) / count > 90) { |
249a8c11 DC |
567 | /* |
568 | * Either there is a lot of contention on the AIL or we | |
569 | * are stuck due to operations in progress. "Stuck" in this | |
570 | * case is defined as >90% of the items we tried to push | |
571 | * were stuck. | |
572 | * | |
573 | * Backoff a bit more to allow some I/O to complete before | |
574 | * continuing from where we were. | |
575 | */ | |
453eac8a | 576 | tout = 20; |
1da177e4 | 577 | } |
0bf6a5bd DC |
578 | |
579 | /* There is more to do, requeue us. */ | |
580 | queue_delayed_work(xfs_syncd_wq, &ailp->xa_work, | |
581 | msecs_to_jiffies(tout)); | |
453eac8a | 582 | } |
1da177e4 | 583 | |
0bf6a5bd DC |
584 | /* |
585 | * This routine is called to move the tail of the AIL forward. It does this by | |
586 | * trying to flush items in the AIL whose lsns are below the given | |
587 | * threshold_lsn. | |
588 | * | |
589 | * The push is run asynchronously in a workqueue, which means the caller needs | |
590 | * to handle waiting on the async flush for space to become available. | |
591 | * We don't want to interrupt any push that is in progress, hence we only queue | |
592 | * work if we set the pushing bit approriately. | |
593 | * | |
594 | * We do this unlocked - we only need to know whether there is anything in the | |
595 | * AIL at the time we are called. We don't need to access the contents of | |
596 | * any of the objects, so the lock is not needed. | |
597 | */ | |
598 | void | |
fd074841 | 599 | xfs_ail_push( |
0bf6a5bd DC |
600 | struct xfs_ail *ailp, |
601 | xfs_lsn_t threshold_lsn) | |
602 | { | |
603 | xfs_log_item_t *lip; | |
604 | ||
605 | lip = xfs_ail_min(ailp); | |
606 | if (!lip || XFS_FORCED_SHUTDOWN(ailp->xa_mount) || | |
607 | XFS_LSN_CMP(threshold_lsn, ailp->xa_target) <= 0) | |
608 | return; | |
609 | ||
610 | /* | |
611 | * Ensure that the new target is noticed in push code before it clears | |
612 | * the XFS_AIL_PUSHING_BIT. | |
613 | */ | |
614 | smp_wmb(); | |
fe0da767 | 615 | xfs_trans_ail_copy_lsn(ailp, &ailp->xa_target, &threshold_lsn); |
0bf6a5bd DC |
616 | if (!test_and_set_bit(XFS_AIL_PUSHING_BIT, &ailp->xa_flags)) |
617 | queue_delayed_work(xfs_syncd_wq, &ailp->xa_work, 0); | |
618 | } | |
1da177e4 | 619 | |
fd074841 DC |
620 | /* |
621 | * Push out all items in the AIL immediately | |
622 | */ | |
623 | void | |
624 | xfs_ail_push_all( | |
625 | struct xfs_ail *ailp) | |
626 | { | |
627 | xfs_lsn_t threshold_lsn = xfs_ail_max_lsn(ailp); | |
628 | ||
629 | if (threshold_lsn) | |
630 | xfs_ail_push(ailp, threshold_lsn); | |
631 | } | |
632 | ||
1da177e4 LT |
633 | /* |
634 | * This is to be called when an item is unlocked that may have | |
635 | * been in the AIL. It will wake up the first member of the AIL | |
636 | * wait list if this item's unlocking might allow it to progress. | |
637 | * If the item is in the AIL, then we need to get the AIL lock | |
638 | * while doing our checking so we don't race with someone going | |
639 | * to sleep waiting for this event in xfs_trans_push_ail(). | |
640 | */ | |
641 | void | |
642 | xfs_trans_unlocked_item( | |
783a2f65 | 643 | struct xfs_ail *ailp, |
1da177e4 LT |
644 | xfs_log_item_t *lip) |
645 | { | |
646 | xfs_log_item_t *min_lip; | |
647 | ||
648 | /* | |
649 | * If we're forcibly shutting down, we may have | |
650 | * unlocked log items arbitrarily. The last thing | |
651 | * we want to do is to move the tail of the log | |
652 | * over some potentially valid data. | |
653 | */ | |
654 | if (!(lip->li_flags & XFS_LI_IN_AIL) || | |
783a2f65 | 655 | XFS_FORCED_SHUTDOWN(ailp->xa_mount)) { |
1da177e4 LT |
656 | return; |
657 | } | |
658 | ||
659 | /* | |
660 | * This is the one case where we can call into xfs_ail_min() | |
661 | * without holding the AIL lock because we only care about the | |
662 | * case where we are at the tail of the AIL. If the object isn't | |
663 | * at the tail, it doesn't matter what result we get back. This | |
664 | * is slightly racy because since we were just unlocked, we could | |
665 | * go to sleep between the call to xfs_ail_min and the call to | |
666 | * xfs_log_move_tail, have someone else lock us, commit to us disk, | |
667 | * move us out of the tail of the AIL, and then we wake up. However, | |
668 | * the call to xfs_log_move_tail() doesn't do anything if there's | |
669 | * not enough free space to wake people up so we're safe calling it. | |
670 | */ | |
783a2f65 | 671 | min_lip = xfs_ail_min(ailp); |
1da177e4 LT |
672 | |
673 | if (min_lip == lip) | |
783a2f65 | 674 | xfs_log_move_tail(ailp->xa_mount, 1); |
1da177e4 LT |
675 | } /* xfs_trans_unlocked_item */ |
676 | ||
0e57f6a3 DC |
677 | /* |
678 | * xfs_trans_ail_update - bulk AIL insertion operation. | |
679 | * | |
680 | * @xfs_trans_ail_update takes an array of log items that all need to be | |
681 | * positioned at the same LSN in the AIL. If an item is not in the AIL, it will | |
682 | * be added. Otherwise, it will be repositioned by removing it and re-adding | |
683 | * it to the AIL. If we move the first item in the AIL, update the log tail to | |
684 | * match the new minimum LSN in the AIL. | |
685 | * | |
686 | * This function takes the AIL lock once to execute the update operations on | |
687 | * all the items in the array, and as such should not be called with the AIL | |
688 | * lock held. As a result, once we have the AIL lock, we need to check each log | |
689 | * item LSN to confirm it needs to be moved forward in the AIL. | |
690 | * | |
691 | * To optimise the insert operation, we delete all the items from the AIL in | |
692 | * the first pass, moving them into a temporary list, then splice the temporary | |
693 | * list into the correct position in the AIL. This avoids needing to do an | |
694 | * insert operation on every item. | |
695 | * | |
696 | * This function must be called with the AIL lock held. The lock is dropped | |
697 | * before returning. | |
698 | */ | |
699 | void | |
700 | xfs_trans_ail_update_bulk( | |
701 | struct xfs_ail *ailp, | |
1d8c95a3 | 702 | struct xfs_ail_cursor *cur, |
0e57f6a3 DC |
703 | struct xfs_log_item **log_items, |
704 | int nr_items, | |
705 | xfs_lsn_t lsn) __releases(ailp->xa_lock) | |
706 | { | |
707 | xfs_log_item_t *mlip; | |
708 | xfs_lsn_t tail_lsn; | |
709 | int mlip_changed = 0; | |
710 | int i; | |
711 | LIST_HEAD(tmp); | |
712 | ||
713 | mlip = xfs_ail_min(ailp); | |
714 | ||
715 | for (i = 0; i < nr_items; i++) { | |
716 | struct xfs_log_item *lip = log_items[i]; | |
717 | if (lip->li_flags & XFS_LI_IN_AIL) { | |
718 | /* check if we really need to move the item */ | |
719 | if (XFS_LSN_CMP(lsn, lip->li_lsn) <= 0) | |
720 | continue; | |
721 | ||
722 | xfs_ail_delete(ailp, lip); | |
723 | if (mlip == lip) | |
724 | mlip_changed = 1; | |
725 | } else { | |
726 | lip->li_flags |= XFS_LI_IN_AIL; | |
727 | } | |
728 | lip->li_lsn = lsn; | |
729 | list_add(&lip->li_ail, &tmp); | |
730 | } | |
731 | ||
1d8c95a3 | 732 | xfs_ail_splice(ailp, cur, &tmp, lsn); |
0e57f6a3 DC |
733 | |
734 | if (!mlip_changed) { | |
735 | spin_unlock(&ailp->xa_lock); | |
736 | return; | |
737 | } | |
738 | ||
739 | /* | |
740 | * It is not safe to access mlip after the AIL lock is dropped, so we | |
741 | * must get a copy of li_lsn before we do so. This is especially | |
742 | * important on 32-bit platforms where accessing and updating 64-bit | |
743 | * values like li_lsn is not atomic. | |
744 | */ | |
745 | mlip = xfs_ail_min(ailp); | |
746 | tail_lsn = mlip->li_lsn; | |
747 | spin_unlock(&ailp->xa_lock); | |
748 | xfs_log_move_tail(ailp->xa_mount, tail_lsn); | |
749 | } | |
750 | ||
30136832 DC |
751 | /* |
752 | * xfs_trans_ail_delete_bulk - remove multiple log items from the AIL | |
753 | * | |
754 | * @xfs_trans_ail_delete_bulk takes an array of log items that all need to | |
755 | * removed from the AIL. The caller is already holding the AIL lock, and done | |
756 | * all the checks necessary to ensure the items passed in via @log_items are | |
757 | * ready for deletion. This includes checking that the items are in the AIL. | |
758 | * | |
759 | * For each log item to be removed, unlink it from the AIL, clear the IN_AIL | |
760 | * flag from the item and reset the item's lsn to 0. If we remove the first | |
761 | * item in the AIL, update the log tail to match the new minimum LSN in the | |
762 | * AIL. | |
763 | * | |
764 | * This function will not drop the AIL lock until all items are removed from | |
765 | * the AIL to minimise the amount of lock traffic on the AIL. This does not | |
766 | * greatly increase the AIL hold time, but does significantly reduce the amount | |
767 | * of traffic on the lock, especially during IO completion. | |
768 | * | |
769 | * This function must be called with the AIL lock held. The lock is dropped | |
770 | * before returning. | |
771 | */ | |
772 | void | |
773 | xfs_trans_ail_delete_bulk( | |
774 | struct xfs_ail *ailp, | |
775 | struct xfs_log_item **log_items, | |
776 | int nr_items) __releases(ailp->xa_lock) | |
777 | { | |
778 | xfs_log_item_t *mlip; | |
779 | xfs_lsn_t tail_lsn; | |
780 | int mlip_changed = 0; | |
781 | int i; | |
782 | ||
783 | mlip = xfs_ail_min(ailp); | |
784 | ||
785 | for (i = 0; i < nr_items; i++) { | |
786 | struct xfs_log_item *lip = log_items[i]; | |
787 | if (!(lip->li_flags & XFS_LI_IN_AIL)) { | |
788 | struct xfs_mount *mp = ailp->xa_mount; | |
789 | ||
790 | spin_unlock(&ailp->xa_lock); | |
791 | if (!XFS_FORCED_SHUTDOWN(mp)) { | |
6a19d939 | 792 | xfs_alert_tag(mp, XFS_PTAG_AILDELETE, |
30136832 DC |
793 | "%s: attempting to delete a log item that is not in the AIL", |
794 | __func__); | |
795 | xfs_force_shutdown(mp, SHUTDOWN_CORRUPT_INCORE); | |
796 | } | |
797 | return; | |
798 | } | |
799 | ||
800 | xfs_ail_delete(ailp, lip); | |
801 | lip->li_flags &= ~XFS_LI_IN_AIL; | |
802 | lip->li_lsn = 0; | |
803 | if (mlip == lip) | |
804 | mlip_changed = 1; | |
805 | } | |
806 | ||
807 | if (!mlip_changed) { | |
808 | spin_unlock(&ailp->xa_lock); | |
809 | return; | |
810 | } | |
811 | ||
812 | /* | |
813 | * It is not safe to access mlip after the AIL lock is dropped, so we | |
814 | * must get a copy of li_lsn before we do so. This is especially | |
815 | * important on 32-bit platforms where accessing and updating 64-bit | |
816 | * values like li_lsn is not atomic. It is possible we've emptied the | |
817 | * AIL here, so if that is the case, pass an LSN of 0 to the tail move. | |
818 | */ | |
819 | mlip = xfs_ail_min(ailp); | |
820 | tail_lsn = mlip ? mlip->li_lsn : 0; | |
821 | spin_unlock(&ailp->xa_lock); | |
822 | xfs_log_move_tail(ailp->xa_mount, tail_lsn); | |
823 | } | |
1da177e4 | 824 | |
1da177e4 LT |
825 | /* |
826 | * The active item list (AIL) is a doubly linked list of log | |
827 | * items sorted by ascending lsn. The base of the list is | |
828 | * a forw/back pointer pair embedded in the xfs mount structure. | |
829 | * The base is initialized with both pointers pointing to the | |
830 | * base. This case always needs to be distinguished, because | |
831 | * the base has no lsn to look at. We almost always insert | |
832 | * at the end of the list, so on inserts we search from the | |
833 | * end of the list to find where the new item belongs. | |
834 | */ | |
835 | ||
836 | /* | |
837 | * Initialize the doubly linked list to point only to itself. | |
838 | */ | |
249a8c11 | 839 | int |
1da177e4 LT |
840 | xfs_trans_ail_init( |
841 | xfs_mount_t *mp) | |
842 | { | |
82fa9012 DC |
843 | struct xfs_ail *ailp; |
844 | ||
845 | ailp = kmem_zalloc(sizeof(struct xfs_ail), KM_MAYFAIL); | |
846 | if (!ailp) | |
847 | return ENOMEM; | |
848 | ||
849 | ailp->xa_mount = mp; | |
850 | INIT_LIST_HEAD(&ailp->xa_ail); | |
c7e8f268 | 851 | spin_lock_init(&ailp->xa_lock); |
0bf6a5bd | 852 | INIT_DELAYED_WORK(&ailp->xa_work, xfs_ail_worker); |
27d8d5fe DC |
853 | mp->m_ail = ailp; |
854 | return 0; | |
249a8c11 DC |
855 | } |
856 | ||
857 | void | |
858 | xfs_trans_ail_destroy( | |
859 | xfs_mount_t *mp) | |
860 | { | |
82fa9012 DC |
861 | struct xfs_ail *ailp = mp->m_ail; |
862 | ||
0bf6a5bd | 863 | cancel_delayed_work_sync(&ailp->xa_work); |
82fa9012 | 864 | kmem_free(ailp); |
1da177e4 | 865 | } |