Commit | Line | Data |
---|---|---|
5274f052 JA |
1 | /* |
2 | * "splice": joining two ropes together by interweaving their strands. | |
3 | * | |
4 | * This is the "extended pipe" functionality, where a pipe is used as | |
5 | * an arbitrary in-memory buffer. Think of a pipe as a small kernel | |
6 | * buffer that you can use to transfer data from one end to the other. | |
7 | * | |
8 | * The traditional unix read/write is extended with a "splice()" operation | |
9 | * that transfers data buffers to or from a pipe buffer. | |
10 | * | |
11 | * Named by Larry McVoy, original implementation from Linus, extended by | |
c2058e06 JA |
12 | * Jens to support splicing to files, network, direct splicing, etc and |
13 | * fixing lots of bugs. | |
5274f052 | 14 | * |
c2058e06 JA |
15 | * Copyright (C) 2005-2006 Jens Axboe <axboe@suse.de> |
16 | * Copyright (C) 2005-2006 Linus Torvalds <torvalds@osdl.org> | |
17 | * Copyright (C) 2006 Ingo Molnar <mingo@elte.hu> | |
5274f052 JA |
18 | * |
19 | */ | |
20 | #include <linux/fs.h> | |
21 | #include <linux/file.h> | |
22 | #include <linux/pagemap.h> | |
23 | #include <linux/pipe_fs_i.h> | |
24 | #include <linux/mm_inline.h> | |
5abc97aa | 25 | #include <linux/swap.h> |
4f6f0bd2 JA |
26 | #include <linux/writeback.h> |
27 | #include <linux/buffer_head.h> | |
a0f06780 | 28 | #include <linux/module.h> |
4f6f0bd2 | 29 | #include <linux/syscalls.h> |
5274f052 JA |
30 | |
31 | /* | |
32 | * Passed to the actors | |
33 | */ | |
34 | struct splice_desc { | |
35 | unsigned int len, total_len; /* current and remaining length */ | |
36 | unsigned int flags; /* splice flags */ | |
37 | struct file *file; /* file to read/write */ | |
38 | loff_t pos; /* file position */ | |
39 | }; | |
40 | ||
83f9135b JA |
41 | /* |
42 | * Attempt to steal a page from a pipe buffer. This should perhaps go into | |
43 | * a vm helper function, it's already simplified quite a bit by the | |
44 | * addition of remove_mapping(). If success is returned, the caller may | |
45 | * attempt to reuse this page for another destination. | |
46 | */ | |
5abc97aa JA |
47 | static int page_cache_pipe_buf_steal(struct pipe_inode_info *info, |
48 | struct pipe_buffer *buf) | |
49 | { | |
50 | struct page *page = buf->page; | |
4f6f0bd2 | 51 | struct address_space *mapping = page_mapping(page); |
5abc97aa JA |
52 | |
53 | WARN_ON(!PageLocked(page)); | |
54 | WARN_ON(!PageUptodate(page)); | |
55 | ||
ad8d6f0a JA |
56 | /* |
57 | * At least for ext2 with nobh option, we need to wait on writeback | |
58 | * completing on this page, since we'll remove it from the pagecache. | |
59 | * Otherwise truncate wont wait on the page, allowing the disk | |
60 | * blocks to be reused by someone else before we actually wrote our | |
61 | * data to them. fs corruption ensues. | |
62 | */ | |
63 | wait_on_page_writeback(page); | |
64 | ||
4f6f0bd2 JA |
65 | if (PagePrivate(page)) |
66 | try_to_release_page(page, mapping_gfp_mask(mapping)); | |
67 | ||
68 | if (!remove_mapping(mapping, page)) | |
5abc97aa JA |
69 | return 1; |
70 | ||
3e7ee3e7 | 71 | buf->flags |= PIPE_BUF_FLAG_STOLEN | PIPE_BUF_FLAG_LRU; |
5abc97aa JA |
72 | return 0; |
73 | } | |
74 | ||
5274f052 JA |
75 | static void page_cache_pipe_buf_release(struct pipe_inode_info *info, |
76 | struct pipe_buffer *buf) | |
77 | { | |
78 | page_cache_release(buf->page); | |
79 | buf->page = NULL; | |
3e7ee3e7 | 80 | buf->flags &= ~(PIPE_BUF_FLAG_STOLEN | PIPE_BUF_FLAG_LRU); |
5274f052 JA |
81 | } |
82 | ||
83 | static void *page_cache_pipe_buf_map(struct file *file, | |
84 | struct pipe_inode_info *info, | |
85 | struct pipe_buffer *buf) | |
86 | { | |
87 | struct page *page = buf->page; | |
49d0b21b | 88 | int err; |
5274f052 JA |
89 | |
90 | if (!PageUptodate(page)) { | |
49d0b21b JA |
91 | lock_page(page); |
92 | ||
93 | /* | |
94 | * Page got truncated/unhashed. This will cause a 0-byte | |
95 | * splice, if this is the first page | |
96 | */ | |
97 | if (!page->mapping) { | |
98 | err = -ENODATA; | |
99 | goto error; | |
100 | } | |
5274f052 | 101 | |
49d0b21b JA |
102 | /* |
103 | * uh oh, read-error from disk | |
104 | */ | |
105 | if (!PageUptodate(page)) { | |
106 | err = -EIO; | |
107 | goto error; | |
108 | } | |
109 | ||
110 | /* | |
111 | * page is ok afterall, fall through to mapping | |
112 | */ | |
5274f052 | 113 | unlock_page(page); |
5274f052 JA |
114 | } |
115 | ||
49d0b21b JA |
116 | return kmap(page); |
117 | error: | |
118 | unlock_page(page); | |
119 | return ERR_PTR(err); | |
5274f052 JA |
120 | } |
121 | ||
122 | static void page_cache_pipe_buf_unmap(struct pipe_inode_info *info, | |
123 | struct pipe_buffer *buf) | |
124 | { | |
5274f052 JA |
125 | kunmap(buf->page); |
126 | } | |
127 | ||
128 | static struct pipe_buf_operations page_cache_pipe_buf_ops = { | |
129 | .can_merge = 0, | |
130 | .map = page_cache_pipe_buf_map, | |
131 | .unmap = page_cache_pipe_buf_unmap, | |
132 | .release = page_cache_pipe_buf_release, | |
5abc97aa | 133 | .steal = page_cache_pipe_buf_steal, |
5274f052 JA |
134 | }; |
135 | ||
83f9135b JA |
136 | /* |
137 | * Pipe output worker. This sets up our pipe format with the page cache | |
138 | * pipe buffer operations. Otherwise very similar to the regular pipe_writev(). | |
139 | */ | |
3a326a2c | 140 | static ssize_t move_to_pipe(struct pipe_inode_info *pipe, struct page **pages, |
5274f052 | 141 | int nr_pages, unsigned long offset, |
29e35094 | 142 | unsigned long len, unsigned int flags) |
5274f052 | 143 | { |
5274f052 JA |
144 | int ret, do_wakeup, i; |
145 | ||
146 | ret = 0; | |
147 | do_wakeup = 0; | |
148 | i = 0; | |
149 | ||
3a326a2c IM |
150 | if (pipe->inode) |
151 | mutex_lock(&pipe->inode->i_mutex); | |
5274f052 | 152 | |
5274f052 | 153 | for (;;) { |
3a326a2c | 154 | if (!pipe->readers) { |
5274f052 JA |
155 | send_sig(SIGPIPE, current, 0); |
156 | if (!ret) | |
157 | ret = -EPIPE; | |
158 | break; | |
159 | } | |
160 | ||
6f767b04 JA |
161 | if (pipe->nrbufs < PIPE_BUFFERS) { |
162 | int newbuf = (pipe->curbuf + pipe->nrbufs) & (PIPE_BUFFERS - 1); | |
3a326a2c | 163 | struct pipe_buffer *buf = pipe->bufs + newbuf; |
5274f052 JA |
164 | struct page *page = pages[i++]; |
165 | unsigned long this_len; | |
166 | ||
167 | this_len = PAGE_CACHE_SIZE - offset; | |
168 | if (this_len > len) | |
169 | this_len = len; | |
170 | ||
171 | buf->page = page; | |
172 | buf->offset = offset; | |
173 | buf->len = this_len; | |
174 | buf->ops = &page_cache_pipe_buf_ops; | |
6f767b04 JA |
175 | pipe->nrbufs++; |
176 | if (pipe->inode) | |
177 | do_wakeup = 1; | |
5274f052 JA |
178 | |
179 | ret += this_len; | |
180 | len -= this_len; | |
181 | offset = 0; | |
182 | if (!--nr_pages) | |
183 | break; | |
184 | if (!len) | |
185 | break; | |
6f767b04 | 186 | if (pipe->nrbufs < PIPE_BUFFERS) |
5274f052 JA |
187 | continue; |
188 | ||
189 | break; | |
190 | } | |
191 | ||
29e35094 LT |
192 | if (flags & SPLICE_F_NONBLOCK) { |
193 | if (!ret) | |
194 | ret = -EAGAIN; | |
195 | break; | |
196 | } | |
197 | ||
5274f052 JA |
198 | if (signal_pending(current)) { |
199 | if (!ret) | |
200 | ret = -ERESTARTSYS; | |
201 | break; | |
202 | } | |
203 | ||
204 | if (do_wakeup) { | |
c0bd1f65 | 205 | smp_mb(); |
3a326a2c IM |
206 | if (waitqueue_active(&pipe->wait)) |
207 | wake_up_interruptible_sync(&pipe->wait); | |
208 | kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); | |
5274f052 JA |
209 | do_wakeup = 0; |
210 | } | |
211 | ||
3a326a2c IM |
212 | pipe->waiting_writers++; |
213 | pipe_wait(pipe); | |
214 | pipe->waiting_writers--; | |
5274f052 JA |
215 | } |
216 | ||
3a326a2c IM |
217 | if (pipe->inode) |
218 | mutex_unlock(&pipe->inode->i_mutex); | |
5274f052 JA |
219 | |
220 | if (do_wakeup) { | |
c0bd1f65 | 221 | smp_mb(); |
3a326a2c IM |
222 | if (waitqueue_active(&pipe->wait)) |
223 | wake_up_interruptible(&pipe->wait); | |
224 | kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); | |
5274f052 JA |
225 | } |
226 | ||
227 | while (i < nr_pages) | |
228 | page_cache_release(pages[i++]); | |
229 | ||
230 | return ret; | |
231 | } | |
232 | ||
3a326a2c IM |
233 | static int |
234 | __generic_file_splice_read(struct file *in, struct pipe_inode_info *pipe, | |
235 | size_t len, unsigned int flags) | |
5274f052 JA |
236 | { |
237 | struct address_space *mapping = in->f_mapping; | |
238 | unsigned int offset, nr_pages; | |
16c523dd | 239 | struct page *pages[PIPE_BUFFERS]; |
5274f052 | 240 | struct page *page; |
16c523dd | 241 | pgoff_t index; |
7480a904 | 242 | int i, error; |
5274f052 JA |
243 | |
244 | index = in->f_pos >> PAGE_CACHE_SHIFT; | |
245 | offset = in->f_pos & ~PAGE_CACHE_MASK; | |
246 | nr_pages = (len + offset + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; | |
247 | ||
248 | if (nr_pages > PIPE_BUFFERS) | |
249 | nr_pages = PIPE_BUFFERS; | |
250 | ||
251 | /* | |
0b749ce3 JA |
252 | * initiate read-ahead on this page range. however, don't call into |
253 | * read-ahead if this is a non-zero offset (we are likely doing small | |
254 | * chunk splice and the page is already there) for a single page. | |
5274f052 | 255 | */ |
0b749ce3 JA |
256 | if (!offset || nr_pages > 1) |
257 | do_page_cache_readahead(mapping, in, index, nr_pages); | |
5274f052 | 258 | |
5274f052 JA |
259 | /* |
260 | * now fill in the holes | |
261 | */ | |
7480a904 | 262 | error = 0; |
16c523dd | 263 | for (i = 0; i < nr_pages; i++, index++) { |
7480a904 | 264 | find_page: |
5274f052 | 265 | /* |
7480a904 | 266 | * lookup the page for this index |
5274f052 | 267 | */ |
7480a904 JA |
268 | page = find_get_page(mapping, index); |
269 | if (!page) { | |
270 | /* | |
271 | * If in nonblock mode then dont block on | |
272 | * readpage (we've kicked readahead so there | |
273 | * will be asynchronous progress): | |
274 | */ | |
275 | if (flags & SPLICE_F_NONBLOCK) | |
276 | break; | |
277 | ||
278 | /* | |
279 | * page didn't exist, allocate one | |
280 | */ | |
281 | page = page_cache_alloc_cold(mapping); | |
282 | if (!page) | |
283 | break; | |
284 | ||
285 | error = add_to_page_cache_lru(page, mapping, index, | |
286 | mapping_gfp_mask(mapping)); | |
287 | if (unlikely(error)) { | |
288 | page_cache_release(page); | |
289 | break; | |
290 | } | |
291 | ||
292 | goto readpage; | |
293 | } | |
294 | ||
295 | /* | |
296 | * If the page isn't uptodate, we may need to start io on it | |
297 | */ | |
298 | if (!PageUptodate(page)) { | |
299 | lock_page(page); | |
300 | ||
301 | /* | |
302 | * page was truncated, stop here. if this isn't the | |
303 | * first page, we'll just complete what we already | |
304 | * added | |
305 | */ | |
306 | if (!page->mapping) { | |
307 | unlock_page(page); | |
308 | page_cache_release(page); | |
309 | break; | |
310 | } | |
311 | /* | |
312 | * page was already under io and is now done, great | |
313 | */ | |
314 | if (PageUptodate(page)) { | |
315 | unlock_page(page); | |
316 | goto fill_it; | |
317 | } | |
5274f052 | 318 | |
7480a904 JA |
319 | readpage: |
320 | /* | |
321 | * need to read in the page | |
322 | */ | |
323 | error = mapping->a_ops->readpage(in, page); | |
5274f052 JA |
324 | |
325 | if (unlikely(error)) { | |
326 | page_cache_release(page); | |
7480a904 JA |
327 | if (error == AOP_TRUNCATED_PAGE) |
328 | goto find_page; | |
5274f052 JA |
329 | break; |
330 | } | |
331 | } | |
7480a904 | 332 | fill_it: |
16c523dd | 333 | pages[i] = page; |
5274f052 JA |
334 | } |
335 | ||
16c523dd JA |
336 | if (i) |
337 | return move_to_pipe(pipe, pages, i, offset, len, flags); | |
5274f052 | 338 | |
7480a904 | 339 | return error; |
5274f052 JA |
340 | } |
341 | ||
83f9135b JA |
342 | /** |
343 | * generic_file_splice_read - splice data from file to a pipe | |
344 | * @in: file to splice from | |
345 | * @pipe: pipe to splice to | |
346 | * @len: number of bytes to splice | |
347 | * @flags: splice modifier flags | |
348 | * | |
349 | * Will read pages from given file and fill them into a pipe. | |
83f9135b | 350 | */ |
3a326a2c | 351 | ssize_t generic_file_splice_read(struct file *in, struct pipe_inode_info *pipe, |
5274f052 JA |
352 | size_t len, unsigned int flags) |
353 | { | |
354 | ssize_t spliced; | |
355 | int ret; | |
356 | ||
357 | ret = 0; | |
358 | spliced = 0; | |
3a326a2c | 359 | |
5274f052 | 360 | while (len) { |
29e35094 | 361 | ret = __generic_file_splice_read(in, pipe, len, flags); |
5274f052 JA |
362 | |
363 | if (ret <= 0) | |
364 | break; | |
365 | ||
366 | in->f_pos += ret; | |
367 | len -= ret; | |
368 | spliced += ret; | |
29e35094 LT |
369 | |
370 | if (!(flags & SPLICE_F_NONBLOCK)) | |
371 | continue; | |
372 | ret = -EAGAIN; | |
373 | break; | |
5274f052 JA |
374 | } |
375 | ||
376 | if (spliced) | |
377 | return spliced; | |
378 | ||
379 | return ret; | |
380 | } | |
381 | ||
059a8f37 JA |
382 | EXPORT_SYMBOL(generic_file_splice_read); |
383 | ||
5274f052 | 384 | /* |
4f6f0bd2 JA |
385 | * Send 'sd->len' bytes to socket from 'sd->file' at position 'sd->pos' |
386 | * using sendpage(). | |
5274f052 JA |
387 | */ |
388 | static int pipe_to_sendpage(struct pipe_inode_info *info, | |
389 | struct pipe_buffer *buf, struct splice_desc *sd) | |
390 | { | |
391 | struct file *file = sd->file; | |
392 | loff_t pos = sd->pos; | |
393 | unsigned int offset; | |
394 | ssize_t ret; | |
395 | void *ptr; | |
b2b39fa4 | 396 | int more; |
5274f052 JA |
397 | |
398 | /* | |
399 | * sub-optimal, but we are limited by the pipe ->map. we don't | |
400 | * need a kmap'ed buffer here, we just want to make sure we | |
401 | * have the page pinned if the pipe page originates from the | |
402 | * page cache | |
403 | */ | |
404 | ptr = buf->ops->map(file, info, buf); | |
405 | if (IS_ERR(ptr)) | |
406 | return PTR_ERR(ptr); | |
407 | ||
408 | offset = pos & ~PAGE_CACHE_MASK; | |
b2b39fa4 | 409 | more = (sd->flags & SPLICE_F_MORE) || sd->len < sd->total_len; |
5274f052 | 410 | |
b2b39fa4 | 411 | ret = file->f_op->sendpage(file, buf->page, offset, sd->len, &pos,more); |
5274f052 JA |
412 | |
413 | buf->ops->unmap(info, buf); | |
414 | if (ret == sd->len) | |
415 | return 0; | |
416 | ||
417 | return -EIO; | |
418 | } | |
419 | ||
420 | /* | |
421 | * This is a little more tricky than the file -> pipe splicing. There are | |
422 | * basically three cases: | |
423 | * | |
424 | * - Destination page already exists in the address space and there | |
425 | * are users of it. For that case we have no other option that | |
426 | * copying the data. Tough luck. | |
427 | * - Destination page already exists in the address space, but there | |
428 | * are no users of it. Make sure it's uptodate, then drop it. Fall | |
429 | * through to last case. | |
430 | * - Destination page does not exist, we can add the pipe page to | |
431 | * the page cache and avoid the copy. | |
432 | * | |
83f9135b JA |
433 | * If asked to move pages to the output file (SPLICE_F_MOVE is set in |
434 | * sd->flags), we attempt to migrate pages from the pipe to the output | |
435 | * file address space page cache. This is possible if no one else has | |
436 | * the pipe page referenced outside of the pipe and page cache. If | |
437 | * SPLICE_F_MOVE isn't set, or we cannot move the page, we simply create | |
438 | * a new page in the output file page cache and fill/dirty that. | |
5274f052 JA |
439 | */ |
440 | static int pipe_to_file(struct pipe_inode_info *info, struct pipe_buffer *buf, | |
441 | struct splice_desc *sd) | |
442 | { | |
443 | struct file *file = sd->file; | |
444 | struct address_space *mapping = file->f_mapping; | |
3e7ee3e7 | 445 | gfp_t gfp_mask = mapping_gfp_mask(mapping); |
5274f052 JA |
446 | unsigned int offset; |
447 | struct page *page; | |
5274f052 | 448 | pgoff_t index; |
5abc97aa | 449 | char *src; |
3e7ee3e7 | 450 | int ret; |
5274f052 JA |
451 | |
452 | /* | |
49d0b21b | 453 | * make sure the data in this buffer is uptodate |
5274f052 JA |
454 | */ |
455 | src = buf->ops->map(file, info, buf); | |
456 | if (IS_ERR(src)) | |
457 | return PTR_ERR(src); | |
458 | ||
459 | index = sd->pos >> PAGE_CACHE_SHIFT; | |
460 | offset = sd->pos & ~PAGE_CACHE_MASK; | |
461 | ||
5274f052 | 462 | /* |
5abc97aa | 463 | * reuse buf page, if SPLICE_F_MOVE is set |
5274f052 | 464 | */ |
5abc97aa | 465 | if (sd->flags & SPLICE_F_MOVE) { |
83f9135b JA |
466 | /* |
467 | * If steal succeeds, buf->page is now pruned from the vm | |
468 | * side (LRU and page cache) and we can reuse it. | |
469 | */ | |
5abc97aa JA |
470 | if (buf->ops->steal(info, buf)) |
471 | goto find_page; | |
472 | ||
49d0b21b JA |
473 | /* |
474 | * this will also set the page locked | |
475 | */ | |
5abc97aa | 476 | page = buf->page; |
3e7ee3e7 | 477 | if (add_to_page_cache(page, mapping, index, gfp_mask)) |
5abc97aa | 478 | goto find_page; |
3e7ee3e7 JA |
479 | |
480 | if (!(buf->flags & PIPE_BUF_FLAG_LRU)) | |
481 | lru_cache_add(page); | |
5abc97aa JA |
482 | } else { |
483 | find_page: | |
484 | ret = -ENOMEM; | |
3e7ee3e7 | 485 | page = find_or_create_page(mapping, index, gfp_mask); |
5abc97aa | 486 | if (!page) |
9aefe431 | 487 | goto out_nomem; |
5abc97aa JA |
488 | |
489 | /* | |
490 | * If the page is uptodate, it is also locked. If it isn't | |
491 | * uptodate, we can mark it uptodate if we are filling the | |
492 | * full page. Otherwise we need to read it in first... | |
493 | */ | |
494 | if (!PageUptodate(page)) { | |
495 | if (sd->len < PAGE_CACHE_SIZE) { | |
496 | ret = mapping->a_ops->readpage(file, page); | |
497 | if (unlikely(ret)) | |
498 | goto out; | |
499 | ||
500 | lock_page(page); | |
501 | ||
502 | if (!PageUptodate(page)) { | |
503 | /* | |
504 | * page got invalidated, repeat | |
505 | */ | |
506 | if (!page->mapping) { | |
507 | unlock_page(page); | |
508 | page_cache_release(page); | |
509 | goto find_page; | |
510 | } | |
511 | ret = -EIO; | |
512 | goto out; | |
5274f052 | 513 | } |
5abc97aa JA |
514 | } else { |
515 | WARN_ON(!PageLocked(page)); | |
516 | SetPageUptodate(page); | |
5274f052 | 517 | } |
5274f052 JA |
518 | } |
519 | } | |
520 | ||
521 | ret = mapping->a_ops->prepare_write(file, page, 0, sd->len); | |
4f6f0bd2 JA |
522 | if (ret == AOP_TRUNCATED_PAGE) { |
523 | page_cache_release(page); | |
524 | goto find_page; | |
525 | } else if (ret) | |
5274f052 JA |
526 | goto out; |
527 | ||
3e7ee3e7 | 528 | if (!(buf->flags & PIPE_BUF_FLAG_STOLEN)) { |
5abc97aa JA |
529 | char *dst = kmap_atomic(page, KM_USER0); |
530 | ||
531 | memcpy(dst + offset, src + buf->offset, sd->len); | |
532 | flush_dcache_page(page); | |
533 | kunmap_atomic(dst, KM_USER0); | |
534 | } | |
5274f052 JA |
535 | |
536 | ret = mapping->a_ops->commit_write(file, page, 0, sd->len); | |
4f6f0bd2 JA |
537 | if (ret == AOP_TRUNCATED_PAGE) { |
538 | page_cache_release(page); | |
539 | goto find_page; | |
540 | } else if (ret) | |
5274f052 JA |
541 | goto out; |
542 | ||
c7f21e4f | 543 | mark_page_accessed(page); |
4f6f0bd2 | 544 | balance_dirty_pages_ratelimited(mapping); |
5274f052 | 545 | out: |
3e7ee3e7 | 546 | if (!(buf->flags & PIPE_BUF_FLAG_STOLEN)) { |
5abc97aa | 547 | page_cache_release(page); |
4f6f0bd2 JA |
548 | unlock_page(page); |
549 | } | |
9aefe431 | 550 | out_nomem: |
5274f052 JA |
551 | buf->ops->unmap(info, buf); |
552 | return ret; | |
553 | } | |
554 | ||
555 | typedef int (splice_actor)(struct pipe_inode_info *, struct pipe_buffer *, | |
556 | struct splice_desc *); | |
557 | ||
83f9135b JA |
558 | /* |
559 | * Pipe input worker. Most of this logic works like a regular pipe, the | |
560 | * key here is the 'actor' worker passed in that actually moves the data | |
561 | * to the wanted destination. See pipe_to_file/pipe_to_sendpage above. | |
562 | */ | |
3a326a2c | 563 | static ssize_t move_from_pipe(struct pipe_inode_info *pipe, struct file *out, |
5274f052 JA |
564 | size_t len, unsigned int flags, |
565 | splice_actor *actor) | |
566 | { | |
5274f052 JA |
567 | int ret, do_wakeup, err; |
568 | struct splice_desc sd; | |
569 | ||
570 | ret = 0; | |
571 | do_wakeup = 0; | |
572 | ||
573 | sd.total_len = len; | |
574 | sd.flags = flags; | |
575 | sd.file = out; | |
576 | sd.pos = out->f_pos; | |
577 | ||
3a326a2c IM |
578 | if (pipe->inode) |
579 | mutex_lock(&pipe->inode->i_mutex); | |
5274f052 | 580 | |
5274f052 | 581 | for (;;) { |
6f767b04 JA |
582 | if (pipe->nrbufs) { |
583 | struct pipe_buffer *buf = pipe->bufs + pipe->curbuf; | |
5274f052 JA |
584 | struct pipe_buf_operations *ops = buf->ops; |
585 | ||
586 | sd.len = buf->len; | |
587 | if (sd.len > sd.total_len) | |
588 | sd.len = sd.total_len; | |
589 | ||
3a326a2c | 590 | err = actor(pipe, buf, &sd); |
5274f052 JA |
591 | if (err) { |
592 | if (!ret && err != -ENODATA) | |
593 | ret = err; | |
594 | ||
595 | break; | |
596 | } | |
597 | ||
598 | ret += sd.len; | |
599 | buf->offset += sd.len; | |
600 | buf->len -= sd.len; | |
601 | if (!buf->len) { | |
602 | buf->ops = NULL; | |
3a326a2c | 603 | ops->release(pipe, buf); |
6f767b04 JA |
604 | pipe->curbuf = (pipe->curbuf + 1) & (PIPE_BUFFERS - 1); |
605 | pipe->nrbufs--; | |
606 | if (pipe->inode) | |
607 | do_wakeup = 1; | |
5274f052 JA |
608 | } |
609 | ||
610 | sd.pos += sd.len; | |
611 | sd.total_len -= sd.len; | |
612 | if (!sd.total_len) | |
613 | break; | |
614 | } | |
615 | ||
6f767b04 | 616 | if (pipe->nrbufs) |
5274f052 | 617 | continue; |
3a326a2c | 618 | if (!pipe->writers) |
5274f052 | 619 | break; |
3a326a2c | 620 | if (!pipe->waiting_writers) { |
5274f052 JA |
621 | if (ret) |
622 | break; | |
623 | } | |
624 | ||
29e35094 LT |
625 | if (flags & SPLICE_F_NONBLOCK) { |
626 | if (!ret) | |
627 | ret = -EAGAIN; | |
628 | break; | |
629 | } | |
630 | ||
5274f052 JA |
631 | if (signal_pending(current)) { |
632 | if (!ret) | |
633 | ret = -ERESTARTSYS; | |
634 | break; | |
635 | } | |
636 | ||
637 | if (do_wakeup) { | |
c0bd1f65 | 638 | smp_mb(); |
3a326a2c IM |
639 | if (waitqueue_active(&pipe->wait)) |
640 | wake_up_interruptible_sync(&pipe->wait); | |
641 | kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT); | |
5274f052 JA |
642 | do_wakeup = 0; |
643 | } | |
644 | ||
3a326a2c | 645 | pipe_wait(pipe); |
5274f052 JA |
646 | } |
647 | ||
3a326a2c IM |
648 | if (pipe->inode) |
649 | mutex_unlock(&pipe->inode->i_mutex); | |
5274f052 JA |
650 | |
651 | if (do_wakeup) { | |
c0bd1f65 | 652 | smp_mb(); |
3a326a2c IM |
653 | if (waitqueue_active(&pipe->wait)) |
654 | wake_up_interruptible(&pipe->wait); | |
655 | kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT); | |
5274f052 JA |
656 | } |
657 | ||
5274f052 | 658 | out->f_pos = sd.pos; |
5274f052 JA |
659 | return ret; |
660 | ||
661 | } | |
662 | ||
83f9135b JA |
663 | /** |
664 | * generic_file_splice_write - splice data from a pipe to a file | |
3a326a2c | 665 | * @pipe: pipe info |
83f9135b JA |
666 | * @out: file to write to |
667 | * @len: number of bytes to splice | |
668 | * @flags: splice modifier flags | |
669 | * | |
670 | * Will either move or copy pages (determined by @flags options) from | |
671 | * the given pipe inode to the given file. | |
672 | * | |
673 | */ | |
3a326a2c IM |
674 | ssize_t |
675 | generic_file_splice_write(struct pipe_inode_info *pipe, struct file *out, | |
676 | size_t len, unsigned int flags) | |
5274f052 | 677 | { |
4f6f0bd2 | 678 | struct address_space *mapping = out->f_mapping; |
3a326a2c IM |
679 | ssize_t ret; |
680 | ||
681 | ret = move_from_pipe(pipe, out, len, flags, pipe_to_file); | |
4f6f0bd2 JA |
682 | |
683 | /* | |
684 | * if file or inode is SYNC and we actually wrote some data, sync it | |
685 | */ | |
686 | if (unlikely((out->f_flags & O_SYNC) || IS_SYNC(mapping->host)) | |
687 | && ret > 0) { | |
688 | struct inode *inode = mapping->host; | |
689 | int err; | |
690 | ||
691 | mutex_lock(&inode->i_mutex); | |
692 | err = generic_osync_inode(mapping->host, mapping, | |
49570e9b | 693 | OSYNC_METADATA|OSYNC_DATA); |
4f6f0bd2 JA |
694 | mutex_unlock(&inode->i_mutex); |
695 | ||
696 | if (err) | |
697 | ret = err; | |
698 | } | |
699 | ||
700 | return ret; | |
5274f052 JA |
701 | } |
702 | ||
059a8f37 JA |
703 | EXPORT_SYMBOL(generic_file_splice_write); |
704 | ||
83f9135b JA |
705 | /** |
706 | * generic_splice_sendpage - splice data from a pipe to a socket | |
707 | * @inode: pipe inode | |
708 | * @out: socket to write to | |
709 | * @len: number of bytes to splice | |
710 | * @flags: splice modifier flags | |
711 | * | |
712 | * Will send @len bytes from the pipe to a network socket. No data copying | |
713 | * is involved. | |
714 | * | |
715 | */ | |
3a326a2c | 716 | ssize_t generic_splice_sendpage(struct pipe_inode_info *pipe, struct file *out, |
5274f052 JA |
717 | size_t len, unsigned int flags) |
718 | { | |
3a326a2c | 719 | return move_from_pipe(pipe, out, len, flags, pipe_to_sendpage); |
5274f052 JA |
720 | } |
721 | ||
059a8f37 | 722 | EXPORT_SYMBOL(generic_splice_sendpage); |
a0f06780 | 723 | |
83f9135b JA |
724 | /* |
725 | * Attempt to initiate a splice from pipe to file. | |
726 | */ | |
3a326a2c | 727 | static long do_splice_from(struct pipe_inode_info *pipe, struct file *out, |
b92ce558 | 728 | size_t len, unsigned int flags) |
5274f052 JA |
729 | { |
730 | loff_t pos; | |
731 | int ret; | |
732 | ||
49570e9b | 733 | if (unlikely(!out->f_op || !out->f_op->splice_write)) |
5274f052 JA |
734 | return -EINVAL; |
735 | ||
49570e9b | 736 | if (unlikely(!(out->f_mode & FMODE_WRITE))) |
5274f052 JA |
737 | return -EBADF; |
738 | ||
739 | pos = out->f_pos; | |
529565dc | 740 | |
5274f052 JA |
741 | ret = rw_verify_area(WRITE, out, &pos, len); |
742 | if (unlikely(ret < 0)) | |
743 | return ret; | |
744 | ||
745 | return out->f_op->splice_write(pipe, out, len, flags); | |
746 | } | |
747 | ||
83f9135b JA |
748 | /* |
749 | * Attempt to initiate a splice from a file to a pipe. | |
750 | */ | |
b92ce558 JA |
751 | static long do_splice_to(struct file *in, struct pipe_inode_info *pipe, |
752 | size_t len, unsigned int flags) | |
5274f052 JA |
753 | { |
754 | loff_t pos, isize, left; | |
755 | int ret; | |
756 | ||
49570e9b | 757 | if (unlikely(!in->f_op || !in->f_op->splice_read)) |
5274f052 JA |
758 | return -EINVAL; |
759 | ||
49570e9b | 760 | if (unlikely(!(in->f_mode & FMODE_READ))) |
5274f052 JA |
761 | return -EBADF; |
762 | ||
763 | pos = in->f_pos; | |
529565dc | 764 | |
5274f052 JA |
765 | ret = rw_verify_area(READ, in, &pos, len); |
766 | if (unlikely(ret < 0)) | |
767 | return ret; | |
768 | ||
769 | isize = i_size_read(in->f_mapping->host); | |
770 | if (unlikely(in->f_pos >= isize)) | |
771 | return 0; | |
772 | ||
773 | left = isize - in->f_pos; | |
49570e9b | 774 | if (unlikely(left < len)) |
5274f052 JA |
775 | len = left; |
776 | ||
777 | return in->f_op->splice_read(in, pipe, len, flags); | |
778 | } | |
779 | ||
b92ce558 JA |
780 | long do_splice_direct(struct file *in, struct file *out, size_t len, |
781 | unsigned int flags) | |
782 | { | |
783 | struct pipe_inode_info *pipe; | |
784 | long ret, bytes; | |
785 | umode_t i_mode; | |
786 | int i; | |
787 | ||
788 | /* | |
789 | * We require the input being a regular file, as we don't want to | |
790 | * randomly drop data for eg socket -> socket splicing. Use the | |
791 | * piped splicing for that! | |
792 | */ | |
793 | i_mode = in->f_dentry->d_inode->i_mode; | |
794 | if (unlikely(!S_ISREG(i_mode) && !S_ISBLK(i_mode))) | |
795 | return -EINVAL; | |
796 | ||
797 | /* | |
798 | * neither in nor out is a pipe, setup an internal pipe attached to | |
799 | * 'out' and transfer the wanted data from 'in' to 'out' through that | |
800 | */ | |
801 | pipe = current->splice_pipe; | |
49570e9b | 802 | if (unlikely(!pipe)) { |
b92ce558 JA |
803 | pipe = alloc_pipe_info(NULL); |
804 | if (!pipe) | |
805 | return -ENOMEM; | |
806 | ||
807 | /* | |
808 | * We don't have an immediate reader, but we'll read the stuff | |
809 | * out of the pipe right after the move_to_pipe(). So set | |
810 | * PIPE_READERS appropriately. | |
811 | */ | |
812 | pipe->readers = 1; | |
813 | ||
814 | current->splice_pipe = pipe; | |
815 | } | |
816 | ||
817 | /* | |
818 | * do the splice | |
819 | */ | |
820 | ret = 0; | |
821 | bytes = 0; | |
822 | ||
823 | while (len) { | |
824 | size_t read_len, max_read_len; | |
825 | ||
826 | /* | |
827 | * Do at most PIPE_BUFFERS pages worth of transfer: | |
828 | */ | |
829 | max_read_len = min(len, (size_t)(PIPE_BUFFERS*PAGE_SIZE)); | |
830 | ||
831 | ret = do_splice_to(in, pipe, max_read_len, flags); | |
832 | if (unlikely(ret < 0)) | |
833 | goto out_release; | |
834 | ||
835 | read_len = ret; | |
836 | ||
837 | /* | |
838 | * NOTE: nonblocking mode only applies to the input. We | |
839 | * must not do the output in nonblocking mode as then we | |
840 | * could get stuck data in the internal pipe: | |
841 | */ | |
842 | ret = do_splice_from(pipe, out, read_len, | |
843 | flags & ~SPLICE_F_NONBLOCK); | |
844 | if (unlikely(ret < 0)) | |
845 | goto out_release; | |
846 | ||
847 | bytes += ret; | |
848 | len -= ret; | |
849 | ||
850 | /* | |
851 | * In nonblocking mode, if we got back a short read then | |
852 | * that was due to either an IO error or due to the | |
853 | * pagecache entry not being there. In the IO error case | |
854 | * the _next_ splice attempt will produce a clean IO error | |
855 | * return value (not a short read), so in both cases it's | |
856 | * correct to break out of the loop here: | |
857 | */ | |
858 | if ((flags & SPLICE_F_NONBLOCK) && (read_len < max_read_len)) | |
859 | break; | |
860 | } | |
861 | ||
862 | pipe->nrbufs = pipe->curbuf = 0; | |
863 | ||
864 | return bytes; | |
865 | ||
866 | out_release: | |
867 | /* | |
868 | * If we did an incomplete transfer we must release | |
869 | * the pipe buffers in question: | |
870 | */ | |
871 | for (i = 0; i < PIPE_BUFFERS; i++) { | |
872 | struct pipe_buffer *buf = pipe->bufs + i; | |
873 | ||
874 | if (buf->ops) { | |
875 | buf->ops->release(pipe, buf); | |
876 | buf->ops = NULL; | |
877 | } | |
878 | } | |
879 | pipe->nrbufs = pipe->curbuf = 0; | |
880 | ||
881 | /* | |
882 | * If we transferred some data, return the number of bytes: | |
883 | */ | |
884 | if (bytes > 0) | |
885 | return bytes; | |
886 | ||
887 | return ret; | |
888 | } | |
889 | ||
890 | EXPORT_SYMBOL(do_splice_direct); | |
891 | ||
83f9135b JA |
892 | /* |
893 | * Determine where to splice to/from. | |
894 | */ | |
529565dc IM |
895 | static long do_splice(struct file *in, loff_t __user *off_in, |
896 | struct file *out, loff_t __user *off_out, | |
897 | size_t len, unsigned int flags) | |
5274f052 | 898 | { |
3a326a2c | 899 | struct pipe_inode_info *pipe; |
5274f052 | 900 | |
3a326a2c | 901 | pipe = in->f_dentry->d_inode->i_pipe; |
529565dc IM |
902 | if (pipe) { |
903 | if (off_in) | |
904 | return -ESPIPE; | |
b92ce558 JA |
905 | if (off_out) { |
906 | if (out->f_op->llseek == no_llseek) | |
907 | return -EINVAL; | |
908 | if (copy_from_user(&out->f_pos, off_out, | |
909 | sizeof(loff_t))) | |
910 | return -EFAULT; | |
911 | } | |
529565dc | 912 | |
b92ce558 | 913 | return do_splice_from(pipe, out, len, flags); |
529565dc | 914 | } |
5274f052 | 915 | |
3a326a2c | 916 | pipe = out->f_dentry->d_inode->i_pipe; |
529565dc IM |
917 | if (pipe) { |
918 | if (off_out) | |
919 | return -ESPIPE; | |
b92ce558 JA |
920 | if (off_in) { |
921 | if (in->f_op->llseek == no_llseek) | |
922 | return -EINVAL; | |
923 | if (copy_from_user(&in->f_pos, off_in, sizeof(loff_t))) | |
924 | return -EFAULT; | |
925 | } | |
529565dc | 926 | |
b92ce558 | 927 | return do_splice_to(in, pipe, len, flags); |
529565dc | 928 | } |
5274f052 JA |
929 | |
930 | return -EINVAL; | |
931 | } | |
932 | ||
529565dc IM |
933 | asmlinkage long sys_splice(int fd_in, loff_t __user *off_in, |
934 | int fd_out, loff_t __user *off_out, | |
935 | size_t len, unsigned int flags) | |
5274f052 JA |
936 | { |
937 | long error; | |
938 | struct file *in, *out; | |
939 | int fput_in, fput_out; | |
940 | ||
941 | if (unlikely(!len)) | |
942 | return 0; | |
943 | ||
944 | error = -EBADF; | |
529565dc | 945 | in = fget_light(fd_in, &fput_in); |
5274f052 JA |
946 | if (in) { |
947 | if (in->f_mode & FMODE_READ) { | |
529565dc | 948 | out = fget_light(fd_out, &fput_out); |
5274f052 JA |
949 | if (out) { |
950 | if (out->f_mode & FMODE_WRITE) | |
529565dc IM |
951 | error = do_splice(in, off_in, |
952 | out, off_out, | |
953 | len, flags); | |
5274f052 JA |
954 | fput_light(out, fput_out); |
955 | } | |
956 | } | |
957 | ||
958 | fput_light(in, fput_in); | |
959 | } | |
960 | ||
961 | return error; | |
962 | } |