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-rw-r--r--block/blk-barrier.c350
1 files changed, 0 insertions, 350 deletions
diff --git a/block/blk-barrier.c b/block/blk-barrier.c
deleted file mode 100644
index f0faefca032f..000000000000
--- a/block/blk-barrier.c
+++ /dev/null
@@ -1,350 +0,0 @@
1/*
2 * Functions related to barrier IO handling
3 */
4#include <linux/kernel.h>
5#include <linux/module.h>
6#include <linux/bio.h>
7#include <linux/blkdev.h>
8#include <linux/gfp.h>
9
10#include "blk.h"
11
12/**
13 * blk_queue_ordered - does this queue support ordered writes
14 * @q: the request queue
15 * @ordered: one of QUEUE_ORDERED_*
16 *
17 * Description:
18 * For journalled file systems, doing ordered writes on a commit
19 * block instead of explicitly doing wait_on_buffer (which is bad
20 * for performance) can be a big win. Block drivers supporting this
21 * feature should call this function and indicate so.
22 *
23 **/
24int blk_queue_ordered(struct request_queue *q, unsigned ordered)
25{
26 if (ordered != QUEUE_ORDERED_NONE &&
27 ordered != QUEUE_ORDERED_DRAIN &&
28 ordered != QUEUE_ORDERED_DRAIN_FLUSH &&
29 ordered != QUEUE_ORDERED_DRAIN_FUA &&
30 ordered != QUEUE_ORDERED_TAG &&
31 ordered != QUEUE_ORDERED_TAG_FLUSH &&
32 ordered != QUEUE_ORDERED_TAG_FUA) {
33 printk(KERN_ERR "blk_queue_ordered: bad value %d\n", ordered);
34 return -EINVAL;
35 }
36
37 q->ordered = ordered;
38 q->next_ordered = ordered;
39
40 return 0;
41}
42EXPORT_SYMBOL(blk_queue_ordered);
43
44/*
45 * Cache flushing for ordered writes handling
46 */
47unsigned blk_ordered_cur_seq(struct request_queue *q)
48{
49 if (!q->ordseq)
50 return 0;
51 return 1 << ffz(q->ordseq);
52}
53
54unsigned blk_ordered_req_seq(struct request *rq)
55{
56 struct request_queue *q = rq->q;
57
58 BUG_ON(q->ordseq == 0);
59
60 if (rq == &q->pre_flush_rq)
61 return QUEUE_ORDSEQ_PREFLUSH;
62 if (rq == &q->bar_rq)
63 return QUEUE_ORDSEQ_BAR;
64 if (rq == &q->post_flush_rq)
65 return QUEUE_ORDSEQ_POSTFLUSH;
66
67 /*
68 * !fs requests don't need to follow barrier ordering. Always
69 * put them at the front. This fixes the following deadlock.
70 *
71 * http://thread.gmane.org/gmane.linux.kernel/537473
72 */
73 if (rq->cmd_type != REQ_TYPE_FS)
74 return QUEUE_ORDSEQ_DRAIN;
75
76 if ((rq->cmd_flags & REQ_ORDERED_COLOR) ==
77 (q->orig_bar_rq->cmd_flags & REQ_ORDERED_COLOR))
78 return QUEUE_ORDSEQ_DRAIN;
79 else
80 return QUEUE_ORDSEQ_DONE;
81}
82
83bool blk_ordered_complete_seq(struct request_queue *q, unsigned seq, int error)
84{
85 struct request *rq;
86
87 if (error && !q->orderr)
88 q->orderr = error;
89
90 BUG_ON(q->ordseq & seq);
91 q->ordseq |= seq;
92
93 if (blk_ordered_cur_seq(q) != QUEUE_ORDSEQ_DONE)
94 return false;
95
96 /*
97 * Okay, sequence complete.
98 */
99 q->ordseq = 0;
100 rq = q->orig_bar_rq;
101 __blk_end_request_all(rq, q->orderr);
102 return true;
103}
104
105static void pre_flush_end_io(struct request *rq, int error)
106{
107 elv_completed_request(rq->q, rq);
108 blk_ordered_complete_seq(rq->q, QUEUE_ORDSEQ_PREFLUSH, error);
109}
110
111static void bar_end_io(struct request *rq, int error)
112{
113 elv_completed_request(rq->q, rq);
114 blk_ordered_complete_seq(rq->q, QUEUE_ORDSEQ_BAR, error);
115}
116
117static void post_flush_end_io(struct request *rq, int error)
118{
119 elv_completed_request(rq->q, rq);
120 blk_ordered_complete_seq(rq->q, QUEUE_ORDSEQ_POSTFLUSH, error);
121}
122
123static void queue_flush(struct request_queue *q, unsigned which)
124{
125 struct request *rq;
126 rq_end_io_fn *end_io;
127
128 if (which == QUEUE_ORDERED_DO_PREFLUSH) {
129 rq = &q->pre_flush_rq;
130 end_io = pre_flush_end_io;
131 } else {
132 rq = &q->post_flush_rq;
133 end_io = post_flush_end_io;
134 }
135
136 blk_rq_init(q, rq);
137 rq->cmd_type = REQ_TYPE_FS;
138 rq->cmd_flags = REQ_HARDBARRIER | REQ_FLUSH;
139 rq->rq_disk = q->orig_bar_rq->rq_disk;
140 rq->end_io = end_io;
141
142 elv_insert(q, rq, ELEVATOR_INSERT_FRONT);
143}
144
145static inline bool start_ordered(struct request_queue *q, struct request **rqp)
146{
147 struct request *rq = *rqp;
148 unsigned skip = 0;
149
150 q->orderr = 0;
151 q->ordered = q->next_ordered;
152 q->ordseq |= QUEUE_ORDSEQ_STARTED;
153
154 /*
155 * For an empty barrier, there's no actual BAR request, which
156 * in turn makes POSTFLUSH unnecessary. Mask them off.
157 */
158 if (!blk_rq_sectors(rq)) {
159 q->ordered &= ~(QUEUE_ORDERED_DO_BAR |
160 QUEUE_ORDERED_DO_POSTFLUSH);
161 /*
162 * Empty barrier on a write-through device w/ ordered
163 * tag has no command to issue and without any command
164 * to issue, ordering by tag can't be used. Drain
165 * instead.
166 */
167 if ((q->ordered & QUEUE_ORDERED_BY_TAG) &&
168 !(q->ordered & QUEUE_ORDERED_DO_PREFLUSH)) {
169 q->ordered &= ~QUEUE_ORDERED_BY_TAG;
170 q->ordered |= QUEUE_ORDERED_BY_DRAIN;
171 }
172 }
173
174 /* stash away the original request */
175 blk_dequeue_request(rq);
176 q->orig_bar_rq = rq;
177 rq = NULL;
178
179 /*
180 * Queue ordered sequence. As we stack them at the head, we
181 * need to queue in reverse order. Note that we rely on that
182 * no fs request uses ELEVATOR_INSERT_FRONT and thus no fs
183 * request gets inbetween ordered sequence.
184 */
185 if (q->ordered & QUEUE_ORDERED_DO_POSTFLUSH) {
186 queue_flush(q, QUEUE_ORDERED_DO_POSTFLUSH);
187 rq = &q->post_flush_rq;
188 } else
189 skip |= QUEUE_ORDSEQ_POSTFLUSH;
190
191 if (q->ordered & QUEUE_ORDERED_DO_BAR) {
192 rq = &q->bar_rq;
193
194 /* initialize proxy request and queue it */
195 blk_rq_init(q, rq);
196 if (bio_data_dir(q->orig_bar_rq->bio) == WRITE)
197 rq->cmd_flags |= REQ_WRITE;
198 if (q->ordered & QUEUE_ORDERED_DO_FUA)
199 rq->cmd_flags |= REQ_FUA;
200 init_request_from_bio(rq, q->orig_bar_rq->bio);
201 rq->end_io = bar_end_io;
202
203 elv_insert(q, rq, ELEVATOR_INSERT_FRONT);
204 } else
205 skip |= QUEUE_ORDSEQ_BAR;
206
207 if (q->ordered & QUEUE_ORDERED_DO_PREFLUSH) {
208 queue_flush(q, QUEUE_ORDERED_DO_PREFLUSH);
209 rq = &q->pre_flush_rq;
210 } else
211 skip |= QUEUE_ORDSEQ_PREFLUSH;
212
213 if ((q->ordered & QUEUE_ORDERED_BY_DRAIN) && queue_in_flight(q))
214 rq = NULL;
215 else
216 skip |= QUEUE_ORDSEQ_DRAIN;
217
218 *rqp = rq;
219
220 /*
221 * Complete skipped sequences. If whole sequence is complete,
222 * return false to tell elevator that this request is gone.
223 */
224 return !blk_ordered_complete_seq(q, skip, 0);
225}
226
227bool blk_do_ordered(struct request_queue *q, struct request **rqp)
228{
229 struct request *rq = *rqp;
230 const int is_barrier = rq->cmd_type == REQ_TYPE_FS &&
231 (rq->cmd_flags & REQ_HARDBARRIER);
232
233 if (!q->ordseq) {
234 if (!is_barrier)
235 return true;
236
237 if (q->next_ordered != QUEUE_ORDERED_NONE)
238 return start_ordered(q, rqp);
239 else {
240 /*
241 * Queue ordering not supported. Terminate
242 * with prejudice.
243 */
244 blk_dequeue_request(rq);
245 __blk_end_request_all(rq, -EOPNOTSUPP);
246 *rqp = NULL;
247 return false;
248 }
249 }
250
251 /*
252 * Ordered sequence in progress
253 */
254
255 /* Special requests are not subject to ordering rules. */
256 if (rq->cmd_type != REQ_TYPE_FS &&
257 rq != &q->pre_flush_rq && rq != &q->post_flush_rq)
258 return true;
259
260 if (q->ordered & QUEUE_ORDERED_BY_TAG) {
261 /* Ordered by tag. Blocking the next barrier is enough. */
262 if (is_barrier && rq != &q->bar_rq)
263 *rqp = NULL;
264 } else {
265 /* Ordered by draining. Wait for turn. */
266 WARN_ON(blk_ordered_req_seq(rq) < blk_ordered_cur_seq(q));
267 if (blk_ordered_req_seq(rq) > blk_ordered_cur_seq(q))
268 *rqp = NULL;
269 }
270
271 return true;
272}
273
274static void bio_end_empty_barrier(struct bio *bio, int err)
275{
276 if (err) {
277 if (err == -EOPNOTSUPP)
278 set_bit(BIO_EOPNOTSUPP, &bio->bi_flags);
279 clear_bit(BIO_UPTODATE, &bio->bi_flags);
280 }
281 if (bio->bi_private)
282 complete(bio->bi_private);
283 bio_put(bio);
284}
285
286/**
287 * blkdev_issue_flush - queue a flush
288 * @bdev: blockdev to issue flush for
289 * @gfp_mask: memory allocation flags (for bio_alloc)
290 * @error_sector: error sector
291 * @flags: BLKDEV_IFL_* flags to control behaviour
292 *
293 * Description:
294 * Issue a flush for the block device in question. Caller can supply
295 * room for storing the error offset in case of a flush error, if they
296 * wish to. If WAIT flag is not passed then caller may check only what
297 * request was pushed in some internal queue for later handling.
298 */
299int blkdev_issue_flush(struct block_device *bdev, gfp_t gfp_mask,
300 sector_t *error_sector, unsigned long flags)
301{
302 DECLARE_COMPLETION_ONSTACK(wait);
303 struct request_queue *q;
304 struct bio *bio;
305 int ret = 0;
306
307 if (bdev->bd_disk == NULL)
308 return -ENXIO;
309
310 q = bdev_get_queue(bdev);
311 if (!q)
312 return -ENXIO;
313
314 /*
315 * some block devices may not have their queue correctly set up here
316 * (e.g. loop device without a backing file) and so issuing a flush
317 * here will panic. Ensure there is a request function before issuing
318 * the barrier.
319 */
320 if (!q->make_request_fn)
321 return -ENXIO;
322
323 bio = bio_alloc(gfp_mask, 0);
324 bio->bi_end_io = bio_end_empty_barrier;
325 bio->bi_bdev = bdev;
326 if (test_bit(BLKDEV_WAIT, &flags))
327 bio->bi_private = &wait;
328
329 bio_get(bio);
330 submit_bio(WRITE_BARRIER, bio);
331 if (test_bit(BLKDEV_WAIT, &flags)) {
332 wait_for_completion(&wait);
333 /*
334 * The driver must store the error location in ->bi_sector, if
335 * it supports it. For non-stacked drivers, this should be
336 * copied from blk_rq_pos(rq).
337 */
338 if (error_sector)
339 *error_sector = bio->bi_sector;
340 }
341
342 if (bio_flagged(bio, BIO_EOPNOTSUPP))
343 ret = -EOPNOTSUPP;
344 else if (!bio_flagged(bio, BIO_UPTODATE))
345 ret = -EIO;
346
347 bio_put(bio);
348 return ret;
349}
350EXPORT_SYMBOL(blkdev_issue_flush);
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