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Commit | Line | Data |
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bd2d0210 TT |
1 | /* |
2 | * linux/fs/ext4/page-io.c | |
3 | * | |
4 | * This contains the new page_io functions for ext4 | |
5 | * | |
6 | * Written by Theodore Ts'o, 2010. | |
7 | */ | |
8 | ||
bd2d0210 TT |
9 | #include <linux/fs.h> |
10 | #include <linux/time.h> | |
11 | #include <linux/jbd2.h> | |
12 | #include <linux/highuid.h> | |
13 | #include <linux/pagemap.h> | |
14 | #include <linux/quotaops.h> | |
15 | #include <linux/string.h> | |
16 | #include <linux/buffer_head.h> | |
17 | #include <linux/writeback.h> | |
18 | #include <linux/pagevec.h> | |
19 | #include <linux/mpage.h> | |
20 | #include <linux/namei.h> | |
21 | #include <linux/uio.h> | |
22 | #include <linux/bio.h> | |
23 | #include <linux/workqueue.h> | |
24 | #include <linux/kernel.h> | |
25 | #include <linux/slab.h> | |
26 | ||
27 | #include "ext4_jbd2.h" | |
28 | #include "xattr.h" | |
29 | #include "acl.h" | |
30 | #include "ext4_extents.h" | |
31 | ||
32 | static struct kmem_cache *io_page_cachep, *io_end_cachep; | |
33 | ||
5dabfc78 | 34 | int __init ext4_init_pageio(void) |
bd2d0210 TT |
35 | { |
36 | io_page_cachep = KMEM_CACHE(ext4_io_page, SLAB_RECLAIM_ACCOUNT); | |
37 | if (io_page_cachep == NULL) | |
38 | return -ENOMEM; | |
39 | io_end_cachep = KMEM_CACHE(ext4_io_end, SLAB_RECLAIM_ACCOUNT); | |
13195184 | 40 | if (io_end_cachep == NULL) { |
bd2d0210 TT |
41 | kmem_cache_destroy(io_page_cachep); |
42 | return -ENOMEM; | |
43 | } | |
bd2d0210 TT |
44 | return 0; |
45 | } | |
46 | ||
5dabfc78 | 47 | void ext4_exit_pageio(void) |
bd2d0210 TT |
48 | { |
49 | kmem_cache_destroy(io_end_cachep); | |
50 | kmem_cache_destroy(io_page_cachep); | |
51 | } | |
52 | ||
f7ad6d2e TT |
53 | void ext4_ioend_wait(struct inode *inode) |
54 | { | |
e9e3bcec | 55 | wait_queue_head_t *wq = ext4_ioend_wq(inode); |
f7ad6d2e TT |
56 | |
57 | wait_event(*wq, (atomic_read(&EXT4_I(inode)->i_ioend_count) == 0)); | |
58 | } | |
59 | ||
83668e71 TT |
60 | static void put_io_page(struct ext4_io_page *io_page) |
61 | { | |
62 | if (atomic_dec_and_test(&io_page->p_count)) { | |
63 | end_page_writeback(io_page->p_page); | |
64 | put_page(io_page->p_page); | |
65 | kmem_cache_free(io_page_cachep, io_page); | |
66 | } | |
67 | } | |
68 | ||
bd2d0210 TT |
69 | void ext4_free_io_end(ext4_io_end_t *io) |
70 | { | |
71 | int i; | |
72 | ||
73 | BUG_ON(!io); | |
74 | if (io->page) | |
75 | put_page(io->page); | |
83668e71 TT |
76 | for (i = 0; i < io->num_io_pages; i++) |
77 | put_io_page(io->pages[i]); | |
bd2d0210 | 78 | io->num_io_pages = 0; |
4e298021 TT |
79 | if (atomic_dec_and_test(&EXT4_I(io->inode)->i_ioend_count)) |
80 | wake_up_all(ext4_ioend_wq(io->inode)); | |
bd2d0210 TT |
81 | kmem_cache_free(io_end_cachep, io); |
82 | } | |
83 | ||
84 | /* | |
85 | * check a range of space and convert unwritten extents to written. | |
d73d5046 TM |
86 | * |
87 | * Called with inode->i_mutex; we depend on this when we manipulate | |
88 | * io->flag, since we could otherwise race with ext4_flush_completed_IO() | |
bd2d0210 TT |
89 | */ |
90 | int ext4_end_io_nolock(ext4_io_end_t *io) | |
91 | { | |
92 | struct inode *inode = io->inode; | |
93 | loff_t offset = io->offset; | |
94 | ssize_t size = io->size; | |
95 | int ret = 0; | |
96 | ||
97 | ext4_debug("ext4_end_io_nolock: io 0x%p from inode %lu,list->next 0x%p," | |
98 | "list->prev 0x%p\n", | |
99 | io, inode->i_ino, io->list.next, io->list.prev); | |
100 | ||
bd2d0210 TT |
101 | ret = ext4_convert_unwritten_extents(inode, offset, size); |
102 | if (ret < 0) { | |
b82e384c TT |
103 | ext4_msg(inode->i_sb, KERN_EMERG, |
104 | "failed to convert unwritten extents to written " | |
105 | "extents -- potential data loss! " | |
106 | "(inode %lu, offset %llu, size %zd, error %d)", | |
107 | inode->i_ino, offset, size, ret); | |
bd2d0210 TT |
108 | } |
109 | ||
110 | if (io->iocb) | |
111 | aio_complete(io->iocb, io->result, 0); | |
e9e3bcec | 112 | |
266991b1 JM |
113 | if (io->flag & EXT4_IO_END_DIRECT) |
114 | inode_dio_done(inode); | |
b82e384c TT |
115 | /* Wake up anyone waiting on unwritten extent conversion */ |
116 | if (atomic_dec_and_test(&EXT4_I(inode)->i_aiodio_unwritten)) | |
117 | wake_up_all(ext4_ioend_wq(io->inode)); | |
bd2d0210 TT |
118 | return ret; |
119 | } | |
120 | ||
121 | /* | |
122 | * work on completed aio dio IO, to convert unwritten extents to extents | |
123 | */ | |
124 | static void ext4_end_io_work(struct work_struct *work) | |
125 | { | |
126 | ext4_io_end_t *io = container_of(work, ext4_io_end_t, work); | |
127 | struct inode *inode = io->inode; | |
128 | struct ext4_inode_info *ei = EXT4_I(inode); | |
129 | unsigned long flags; | |
bd2d0210 | 130 | |
d73d5046 TM |
131 | spin_lock_irqsave(&ei->i_completed_io_lock, flags); |
132 | if (list_empty(&io->list)) { | |
133 | spin_unlock_irqrestore(&ei->i_completed_io_lock, flags); | |
134 | goto free; | |
135 | } | |
d73d5046 | 136 | |
8c0bec21 | 137 | if (!mutex_trylock(&inode->i_mutex)) { |
b82e384c | 138 | spin_unlock_irqrestore(&ei->i_completed_io_lock, flags); |
8c0bec21 JZ |
139 | /* |
140 | * Requeue the work instead of waiting so that the work | |
141 | * items queued after this can be processed. | |
142 | */ | |
143 | queue_work(EXT4_SB(inode->i_sb)->dio_unwritten_wq, &io->work); | |
144 | /* | |
145 | * To prevent the ext4-dio-unwritten thread from keeping | |
146 | * requeueing end_io requests and occupying cpu for too long, | |
147 | * yield the cpu if it sees an end_io request that has already | |
148 | * been requeued. | |
149 | */ | |
150 | if (io->flag & EXT4_IO_END_QUEUED) | |
151 | yield(); | |
152 | io->flag |= EXT4_IO_END_QUEUED; | |
153 | return; | |
154 | } | |
b82e384c | 155 | list_del_init(&io->list); |
bd2d0210 | 156 | spin_unlock_irqrestore(&ei->i_completed_io_lock, flags); |
b82e384c | 157 | (void) ext4_end_io_nolock(io); |
bd2d0210 | 158 | mutex_unlock(&inode->i_mutex); |
d73d5046 | 159 | free: |
bd2d0210 TT |
160 | ext4_free_io_end(io); |
161 | } | |
162 | ||
163 | ext4_io_end_t *ext4_init_io_end(struct inode *inode, gfp_t flags) | |
164 | { | |
b17b35ec | 165 | ext4_io_end_t *io = kmem_cache_zalloc(io_end_cachep, flags); |
bd2d0210 | 166 | if (io) { |
f7ad6d2e TT |
167 | atomic_inc(&EXT4_I(inode)->i_ioend_count); |
168 | io->inode = inode; | |
bd2d0210 TT |
169 | INIT_WORK(&io->work, ext4_end_io_work); |
170 | INIT_LIST_HEAD(&io->list); | |
171 | } | |
172 | return io; | |
173 | } | |
174 | ||
175 | /* | |
176 | * Print an buffer I/O error compatible with the fs/buffer.c. This | |
177 | * provides compatibility with dmesg scrapers that look for a specific | |
178 | * buffer I/O error message. We really need a unified error reporting | |
179 | * structure to userspace ala Digital Unix's uerf system, but it's | |
180 | * probably not going to happen in my lifetime, due to LKML politics... | |
181 | */ | |
182 | static void buffer_io_error(struct buffer_head *bh) | |
183 | { | |
184 | char b[BDEVNAME_SIZE]; | |
185 | printk(KERN_ERR "Buffer I/O error on device %s, logical block %llu\n", | |
186 | bdevname(bh->b_bdev, b), | |
187 | (unsigned long long)bh->b_blocknr); | |
188 | } | |
189 | ||
190 | static void ext4_end_bio(struct bio *bio, int error) | |
191 | { | |
192 | ext4_io_end_t *io_end = bio->bi_private; | |
193 | struct workqueue_struct *wq; | |
194 | struct inode *inode; | |
195 | unsigned long flags; | |
bd2d0210 | 196 | int i; |
d50bdd5a | 197 | sector_t bi_sector = bio->bi_sector; |
bd2d0210 TT |
198 | |
199 | BUG_ON(!io_end); | |
bd2d0210 TT |
200 | bio->bi_private = NULL; |
201 | bio->bi_end_io = NULL; | |
202 | if (test_bit(BIO_UPTODATE, &bio->bi_flags)) | |
203 | error = 0; | |
bd2d0210 TT |
204 | bio_put(bio); |
205 | ||
bd2d0210 TT |
206 | for (i = 0; i < io_end->num_io_pages; i++) { |
207 | struct page *page = io_end->pages[i]->p_page; | |
208 | struct buffer_head *bh, *head; | |
39db00f1 CW |
209 | loff_t offset; |
210 | loff_t io_end_offset; | |
bd2d0210 | 211 | |
39db00f1 | 212 | if (error) { |
bd2d0210 | 213 | SetPageError(page); |
39db00f1 CW |
214 | set_bit(AS_EIO, &page->mapping->flags); |
215 | head = page_buffers(page); | |
216 | BUG_ON(!head); | |
217 | ||
218 | io_end_offset = io_end->offset + io_end->size; | |
bd2d0210 TT |
219 | |
220 | offset = (sector_t) page->index << PAGE_CACHE_SHIFT; | |
221 | bh = head; | |
222 | do { | |
223 | if ((offset >= io_end->offset) && | |
39db00f1 CW |
224 | (offset+bh->b_size <= io_end_offset)) |
225 | buffer_io_error(bh); | |
226 | ||
bd2d0210 TT |
227 | offset += bh->b_size; |
228 | bh = bh->b_this_page; | |
229 | } while (bh != head); | |
230 | } | |
231 | ||
08da1193 | 232 | put_io_page(io_end->pages[i]); |
bd2d0210 | 233 | } |
bd2d0210 | 234 | io_end->num_io_pages = 0; |
f7ad6d2e TT |
235 | inode = io_end->inode; |
236 | ||
237 | if (error) { | |
238 | io_end->flag |= EXT4_IO_END_ERROR; | |
239 | ext4_warning(inode->i_sb, "I/O error writing to inode %lu " | |
240 | "(offset %llu size %ld starting block %llu)", | |
241 | inode->i_ino, | |
242 | (unsigned long long) io_end->offset, | |
243 | (long) io_end->size, | |
244 | (unsigned long long) | |
d50bdd5a | 245 | bi_sector >> (inode->i_blkbits - 9)); |
f7ad6d2e | 246 | } |
bd2d0210 | 247 | |
b6168443 TT |
248 | if (!(io_end->flag & EXT4_IO_END_UNWRITTEN)) { |
249 | ext4_free_io_end(io_end); | |
250 | return; | |
251 | } | |
252 | ||
bd2d0210 TT |
253 | /* Add the io_end to per-inode completed io list*/ |
254 | spin_lock_irqsave(&EXT4_I(inode)->i_completed_io_lock, flags); | |
255 | list_add_tail(&io_end->list, &EXT4_I(inode)->i_completed_io_list); | |
256 | spin_unlock_irqrestore(&EXT4_I(inode)->i_completed_io_lock, flags); | |
257 | ||
258 | wq = EXT4_SB(inode->i_sb)->dio_unwritten_wq; | |
259 | /* queue the work to convert unwritten extents to written */ | |
260 | queue_work(wq, &io_end->work); | |
261 | } | |
262 | ||
263 | void ext4_io_submit(struct ext4_io_submit *io) | |
264 | { | |
265 | struct bio *bio = io->io_bio; | |
266 | ||
267 | if (bio) { | |
268 | bio_get(io->io_bio); | |
269 | submit_bio(io->io_op, io->io_bio); | |
270 | BUG_ON(bio_flagged(io->io_bio, BIO_EOPNOTSUPP)); | |
271 | bio_put(io->io_bio); | |
272 | } | |
7dc57615 | 273 | io->io_bio = NULL; |
bd2d0210 | 274 | io->io_op = 0; |
7dc57615 | 275 | io->io_end = NULL; |
bd2d0210 TT |
276 | } |
277 | ||
278 | static int io_submit_init(struct ext4_io_submit *io, | |
279 | struct inode *inode, | |
280 | struct writeback_control *wbc, | |
281 | struct buffer_head *bh) | |
282 | { | |
283 | ext4_io_end_t *io_end; | |
284 | struct page *page = bh->b_page; | |
285 | int nvecs = bio_get_nr_vecs(bh->b_bdev); | |
286 | struct bio *bio; | |
287 | ||
288 | io_end = ext4_init_io_end(inode, GFP_NOFS); | |
289 | if (!io_end) | |
290 | return -ENOMEM; | |
275d3ba6 | 291 | bio = bio_alloc(GFP_NOIO, min(nvecs, BIO_MAX_PAGES)); |
bd2d0210 TT |
292 | bio->bi_sector = bh->b_blocknr * (bh->b_size >> 9); |
293 | bio->bi_bdev = bh->b_bdev; | |
294 | bio->bi_private = io->io_end = io_end; | |
295 | bio->bi_end_io = ext4_end_bio; | |
296 | ||
bd2d0210 TT |
297 | io_end->offset = (page->index << PAGE_CACHE_SHIFT) + bh_offset(bh); |
298 | ||
299 | io->io_bio = bio; | |
721a9602 | 300 | io->io_op = (wbc->sync_mode == WB_SYNC_ALL ? WRITE_SYNC : WRITE); |
bd2d0210 TT |
301 | io->io_next_block = bh->b_blocknr; |
302 | return 0; | |
303 | } | |
304 | ||
305 | static int io_submit_add_bh(struct ext4_io_submit *io, | |
306 | struct ext4_io_page *io_page, | |
307 | struct inode *inode, | |
308 | struct writeback_control *wbc, | |
309 | struct buffer_head *bh) | |
310 | { | |
311 | ext4_io_end_t *io_end; | |
312 | int ret; | |
313 | ||
314 | if (buffer_new(bh)) { | |
315 | clear_buffer_new(bh); | |
316 | unmap_underlying_metadata(bh->b_bdev, bh->b_blocknr); | |
317 | } | |
318 | ||
319 | if (!buffer_mapped(bh) || buffer_delay(bh)) { | |
320 | if (!buffer_mapped(bh)) | |
321 | clear_buffer_dirty(bh); | |
322 | if (io->io_bio) | |
323 | ext4_io_submit(io); | |
324 | return 0; | |
325 | } | |
326 | ||
327 | if (io->io_bio && bh->b_blocknr != io->io_next_block) { | |
328 | submit_and_retry: | |
329 | ext4_io_submit(io); | |
330 | } | |
331 | if (io->io_bio == NULL) { | |
332 | ret = io_submit_init(io, inode, wbc, bh); | |
333 | if (ret) | |
334 | return ret; | |
335 | } | |
336 | io_end = io->io_end; | |
337 | if ((io_end->num_io_pages >= MAX_IO_PAGES) && | |
338 | (io_end->pages[io_end->num_io_pages-1] != io_page)) | |
339 | goto submit_and_retry; | |
0edeb71d TM |
340 | if (buffer_uninit(bh)) |
341 | ext4_set_io_unwritten_flag(inode, io_end); | |
bd2d0210 TT |
342 | io->io_end->size += bh->b_size; |
343 | io->io_next_block++; | |
344 | ret = bio_add_page(io->io_bio, bh->b_page, bh->b_size, bh_offset(bh)); | |
345 | if (ret != bh->b_size) | |
346 | goto submit_and_retry; | |
347 | if ((io_end->num_io_pages == 0) || | |
348 | (io_end->pages[io_end->num_io_pages-1] != io_page)) { | |
349 | io_end->pages[io_end->num_io_pages++] = io_page; | |
83668e71 | 350 | atomic_inc(&io_page->p_count); |
bd2d0210 TT |
351 | } |
352 | return 0; | |
353 | } | |
354 | ||
355 | int ext4_bio_write_page(struct ext4_io_submit *io, | |
356 | struct page *page, | |
357 | int len, | |
358 | struct writeback_control *wbc) | |
359 | { | |
360 | struct inode *inode = page->mapping->host; | |
361 | unsigned block_start, block_end, blocksize; | |
362 | struct ext4_io_page *io_page; | |
363 | struct buffer_head *bh, *head; | |
364 | int ret = 0; | |
365 | ||
366 | blocksize = 1 << inode->i_blkbits; | |
367 | ||
d50bdd5a | 368 | BUG_ON(!PageLocked(page)); |
bd2d0210 | 369 | BUG_ON(PageWriteback(page)); |
bd2d0210 TT |
370 | |
371 | io_page = kmem_cache_alloc(io_page_cachep, GFP_NOFS); | |
372 | if (!io_page) { | |
373 | set_page_dirty(page); | |
374 | unlock_page(page); | |
375 | return -ENOMEM; | |
376 | } | |
377 | io_page->p_page = page; | |
83668e71 | 378 | atomic_set(&io_page->p_count, 1); |
bd2d0210 | 379 | get_page(page); |
a54aa761 TT |
380 | set_page_writeback(page); |
381 | ClearPageError(page); | |
bd2d0210 TT |
382 | |
383 | for (bh = head = page_buffers(page), block_start = 0; | |
384 | bh != head || !block_start; | |
385 | block_start = block_end, bh = bh->b_this_page) { | |
d50bdd5a | 386 | |
bd2d0210 TT |
387 | block_end = block_start + blocksize; |
388 | if (block_start >= len) { | |
5a0dc736 YY |
389 | /* |
390 | * Comments copied from block_write_full_page_endio: | |
391 | * | |
392 | * The page straddles i_size. It must be zeroed out on | |
393 | * each and every writepage invocation because it may | |
394 | * be mmapped. "A file is mapped in multiples of the | |
395 | * page size. For a file that is not a multiple of | |
396 | * the page size, the remaining memory is zeroed when | |
397 | * mapped, and writes to that region are not written | |
398 | * out to the file." | |
399 | */ | |
400 | zero_user_segment(page, block_start, block_end); | |
bd2d0210 TT |
401 | clear_buffer_dirty(bh); |
402 | set_buffer_uptodate(bh); | |
403 | continue; | |
404 | } | |
d50bdd5a | 405 | clear_buffer_dirty(bh); |
bd2d0210 TT |
406 | ret = io_submit_add_bh(io, io_page, inode, wbc, bh); |
407 | if (ret) { | |
408 | /* | |
409 | * We only get here on ENOMEM. Not much else | |
410 | * we can do but mark the page as dirty, and | |
411 | * better luck next time. | |
412 | */ | |
413 | set_page_dirty(page); | |
414 | break; | |
415 | } | |
416 | } | |
417 | unlock_page(page); | |
418 | /* | |
419 | * If the page was truncated before we could do the writeback, | |
420 | * or we had a memory allocation error while trying to write | |
421 | * the first buffer head, we won't have submitted any pages for | |
422 | * I/O. In that case we need to make sure we've cleared the | |
423 | * PageWriteback bit from the page to prevent the system from | |
424 | * wedging later on. | |
425 | */ | |
83668e71 | 426 | put_io_page(io_page); |
bd2d0210 TT |
427 | return ret; |
428 | } |