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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 | ||
9 | #include <linux/module.h> | |
10 | #include <linux/fs.h> | |
11 | #include <linux/time.h> | |
12 | #include <linux/jbd2.h> | |
13 | #include <linux/highuid.h> | |
14 | #include <linux/pagemap.h> | |
15 | #include <linux/quotaops.h> | |
16 | #include <linux/string.h> | |
17 | #include <linux/buffer_head.h> | |
18 | #include <linux/writeback.h> | |
19 | #include <linux/pagevec.h> | |
20 | #include <linux/mpage.h> | |
21 | #include <linux/namei.h> | |
22 | #include <linux/uio.h> | |
23 | #include <linux/bio.h> | |
24 | #include <linux/workqueue.h> | |
25 | #include <linux/kernel.h> | |
26 | #include <linux/slab.h> | |
27 | ||
28 | #include "ext4_jbd2.h" | |
29 | #include "xattr.h" | |
30 | #include "acl.h" | |
31 | #include "ext4_extents.h" | |
32 | ||
33 | static struct kmem_cache *io_page_cachep, *io_end_cachep; | |
34 | ||
35 | int __init init_ext4_pageio(void) | |
36 | { | |
37 | io_page_cachep = KMEM_CACHE(ext4_io_page, SLAB_RECLAIM_ACCOUNT); | |
38 | if (io_page_cachep == NULL) | |
39 | return -ENOMEM; | |
40 | io_end_cachep = KMEM_CACHE(ext4_io_end, SLAB_RECLAIM_ACCOUNT); | |
41 | if (io_page_cachep == NULL) { | |
42 | kmem_cache_destroy(io_page_cachep); | |
43 | return -ENOMEM; | |
44 | } | |
45 | ||
46 | return 0; | |
47 | } | |
48 | ||
49 | void exit_ext4_pageio(void) | |
50 | { | |
51 | kmem_cache_destroy(io_end_cachep); | |
52 | kmem_cache_destroy(io_page_cachep); | |
53 | } | |
54 | ||
55 | void ext4_free_io_end(ext4_io_end_t *io) | |
56 | { | |
57 | int i; | |
58 | ||
59 | BUG_ON(!io); | |
60 | if (io->page) | |
61 | put_page(io->page); | |
62 | for (i = 0; i < io->num_io_pages; i++) { | |
63 | if (--io->pages[i]->p_count == 0) { | |
64 | struct page *page = io->pages[i]->p_page; | |
65 | ||
66 | end_page_writeback(page); | |
67 | put_page(page); | |
68 | kmem_cache_free(io_page_cachep, io->pages[i]); | |
69 | } | |
70 | } | |
71 | io->num_io_pages = 0; | |
72 | iput(io->inode); | |
73 | kmem_cache_free(io_end_cachep, io); | |
74 | } | |
75 | ||
76 | /* | |
77 | * check a range of space and convert unwritten extents to written. | |
78 | */ | |
79 | int ext4_end_io_nolock(ext4_io_end_t *io) | |
80 | { | |
81 | struct inode *inode = io->inode; | |
82 | loff_t offset = io->offset; | |
83 | ssize_t size = io->size; | |
84 | int ret = 0; | |
85 | ||
86 | ext4_debug("ext4_end_io_nolock: io 0x%p from inode %lu,list->next 0x%p," | |
87 | "list->prev 0x%p\n", | |
88 | io, inode->i_ino, io->list.next, io->list.prev); | |
89 | ||
90 | if (list_empty(&io->list)) | |
91 | return ret; | |
92 | ||
93 | if (!(io->flag & EXT4_IO_END_UNWRITTEN)) | |
94 | return ret; | |
95 | ||
96 | ret = ext4_convert_unwritten_extents(inode, offset, size); | |
97 | if (ret < 0) { | |
98 | printk(KERN_EMERG "%s: failed to convert unwritten " | |
99 | "extents to written extents, error is %d " | |
100 | "io is still on inode %lu aio dio list\n", | |
101 | __func__, ret, inode->i_ino); | |
102 | return ret; | |
103 | } | |
104 | ||
105 | if (io->iocb) | |
106 | aio_complete(io->iocb, io->result, 0); | |
107 | /* clear the DIO AIO unwritten flag */ | |
108 | io->flag &= ~EXT4_IO_END_UNWRITTEN; | |
109 | return ret; | |
110 | } | |
111 | ||
112 | /* | |
113 | * work on completed aio dio IO, to convert unwritten extents to extents | |
114 | */ | |
115 | static void ext4_end_io_work(struct work_struct *work) | |
116 | { | |
117 | ext4_io_end_t *io = container_of(work, ext4_io_end_t, work); | |
118 | struct inode *inode = io->inode; | |
119 | struct ext4_inode_info *ei = EXT4_I(inode); | |
120 | unsigned long flags; | |
121 | int ret; | |
122 | ||
123 | mutex_lock(&inode->i_mutex); | |
124 | ret = ext4_end_io_nolock(io); | |
125 | if (ret < 0) { | |
126 | mutex_unlock(&inode->i_mutex); | |
127 | return; | |
128 | } | |
129 | ||
130 | spin_lock_irqsave(&ei->i_completed_io_lock, flags); | |
131 | if (!list_empty(&io->list)) | |
132 | list_del_init(&io->list); | |
133 | spin_unlock_irqrestore(&ei->i_completed_io_lock, flags); | |
134 | mutex_unlock(&inode->i_mutex); | |
135 | ext4_free_io_end(io); | |
136 | } | |
137 | ||
138 | ext4_io_end_t *ext4_init_io_end(struct inode *inode, gfp_t flags) | |
139 | { | |
140 | ext4_io_end_t *io = NULL; | |
141 | ||
142 | io = kmem_cache_alloc(io_end_cachep, flags); | |
143 | if (io) { | |
144 | memset(io, 0, sizeof(*io)); | |
145 | io->inode = igrab(inode); | |
146 | BUG_ON(!io->inode); | |
147 | INIT_WORK(&io->work, ext4_end_io_work); | |
148 | INIT_LIST_HEAD(&io->list); | |
149 | } | |
150 | return io; | |
151 | } | |
152 | ||
153 | /* | |
154 | * Print an buffer I/O error compatible with the fs/buffer.c. This | |
155 | * provides compatibility with dmesg scrapers that look for a specific | |
156 | * buffer I/O error message. We really need a unified error reporting | |
157 | * structure to userspace ala Digital Unix's uerf system, but it's | |
158 | * probably not going to happen in my lifetime, due to LKML politics... | |
159 | */ | |
160 | static void buffer_io_error(struct buffer_head *bh) | |
161 | { | |
162 | char b[BDEVNAME_SIZE]; | |
163 | printk(KERN_ERR "Buffer I/O error on device %s, logical block %llu\n", | |
164 | bdevname(bh->b_bdev, b), | |
165 | (unsigned long long)bh->b_blocknr); | |
166 | } | |
167 | ||
168 | static void ext4_end_bio(struct bio *bio, int error) | |
169 | { | |
170 | ext4_io_end_t *io_end = bio->bi_private; | |
171 | struct workqueue_struct *wq; | |
172 | struct inode *inode; | |
173 | unsigned long flags; | |
174 | ext4_fsblk_t err_block; | |
175 | int i; | |
176 | ||
177 | BUG_ON(!io_end); | |
178 | inode = io_end->inode; | |
179 | bio->bi_private = NULL; | |
180 | bio->bi_end_io = NULL; | |
181 | if (test_bit(BIO_UPTODATE, &bio->bi_flags)) | |
182 | error = 0; | |
183 | err_block = bio->bi_sector >> (inode->i_blkbits - 9); | |
184 | bio_put(bio); | |
185 | ||
186 | if (!(inode->i_sb->s_flags & MS_ACTIVE)) { | |
187 | pr_err("sb umounted, discard end_io request for inode %lu\n", | |
188 | io_end->inode->i_ino); | |
189 | ext4_free_io_end(io_end); | |
190 | return; | |
191 | } | |
192 | ||
193 | if (error) { | |
194 | io_end->flag |= EXT4_IO_END_ERROR; | |
195 | ext4_warning(inode->i_sb, "I/O error writing to inode %lu " | |
196 | "(offset %llu size %ld starting block %llu)", | |
197 | inode->i_ino, | |
198 | (unsigned long long) io_end->offset, | |
199 | (long) io_end->size, | |
200 | (unsigned long long) err_block); | |
201 | } | |
202 | ||
203 | for (i = 0; i < io_end->num_io_pages; i++) { | |
204 | struct page *page = io_end->pages[i]->p_page; | |
205 | struct buffer_head *bh, *head; | |
206 | int partial_write = 0; | |
207 | ||
208 | head = page_buffers(page); | |
209 | if (error) | |
210 | SetPageError(page); | |
211 | BUG_ON(!head); | |
212 | if (head->b_size == PAGE_CACHE_SIZE) | |
213 | clear_buffer_dirty(head); | |
214 | else { | |
215 | loff_t offset; | |
216 | loff_t io_end_offset = io_end->offset + io_end->size; | |
217 | ||
218 | offset = (sector_t) page->index << PAGE_CACHE_SHIFT; | |
219 | bh = head; | |
220 | do { | |
221 | if ((offset >= io_end->offset) && | |
222 | (offset+bh->b_size <= io_end_offset)) { | |
223 | if (error) | |
224 | buffer_io_error(bh); | |
225 | ||
226 | clear_buffer_dirty(bh); | |
227 | } | |
228 | if (buffer_delay(bh)) | |
229 | partial_write = 1; | |
230 | else if (!buffer_mapped(bh)) | |
231 | clear_buffer_dirty(bh); | |
232 | else if (buffer_dirty(bh)) | |
233 | partial_write = 1; | |
234 | offset += bh->b_size; | |
235 | bh = bh->b_this_page; | |
236 | } while (bh != head); | |
237 | } | |
238 | ||
239 | if (--io_end->pages[i]->p_count == 0) { | |
240 | struct page *page = io_end->pages[i]->p_page; | |
241 | ||
242 | end_page_writeback(page); | |
243 | put_page(page); | |
244 | kmem_cache_free(io_page_cachep, io_end->pages[i]); | |
245 | } | |
246 | ||
247 | /* | |
248 | * If this is a partial write which happened to make | |
249 | * all buffers uptodate then we can optimize away a | |
250 | * bogus readpage() for the next read(). Here we | |
251 | * 'discover' whether the page went uptodate as a | |
252 | * result of this (potentially partial) write. | |
253 | */ | |
254 | if (!partial_write) | |
255 | SetPageUptodate(page); | |
256 | } | |
257 | ||
258 | io_end->num_io_pages = 0; | |
259 | ||
260 | /* Add the io_end to per-inode completed io list*/ | |
261 | spin_lock_irqsave(&EXT4_I(inode)->i_completed_io_lock, flags); | |
262 | list_add_tail(&io_end->list, &EXT4_I(inode)->i_completed_io_list); | |
263 | spin_unlock_irqrestore(&EXT4_I(inode)->i_completed_io_lock, flags); | |
264 | ||
265 | wq = EXT4_SB(inode->i_sb)->dio_unwritten_wq; | |
266 | /* queue the work to convert unwritten extents to written */ | |
267 | queue_work(wq, &io_end->work); | |
268 | } | |
269 | ||
270 | void ext4_io_submit(struct ext4_io_submit *io) | |
271 | { | |
272 | struct bio *bio = io->io_bio; | |
273 | ||
274 | if (bio) { | |
275 | bio_get(io->io_bio); | |
276 | submit_bio(io->io_op, io->io_bio); | |
277 | BUG_ON(bio_flagged(io->io_bio, BIO_EOPNOTSUPP)); | |
278 | bio_put(io->io_bio); | |
279 | } | |
280 | io->io_bio = 0; | |
281 | io->io_op = 0; | |
282 | io->io_end = 0; | |
283 | } | |
284 | ||
285 | static int io_submit_init(struct ext4_io_submit *io, | |
286 | struct inode *inode, | |
287 | struct writeback_control *wbc, | |
288 | struct buffer_head *bh) | |
289 | { | |
290 | ext4_io_end_t *io_end; | |
291 | struct page *page = bh->b_page; | |
292 | int nvecs = bio_get_nr_vecs(bh->b_bdev); | |
293 | struct bio *bio; | |
294 | ||
295 | io_end = ext4_init_io_end(inode, GFP_NOFS); | |
296 | if (!io_end) | |
297 | return -ENOMEM; | |
298 | do { | |
299 | bio = bio_alloc(GFP_NOIO, nvecs); | |
300 | nvecs >>= 1; | |
301 | } while (bio == NULL); | |
302 | ||
303 | bio->bi_sector = bh->b_blocknr * (bh->b_size >> 9); | |
304 | bio->bi_bdev = bh->b_bdev; | |
305 | bio->bi_private = io->io_end = io_end; | |
306 | bio->bi_end_io = ext4_end_bio; | |
307 | ||
308 | io_end->inode = inode; | |
309 | io_end->offset = (page->index << PAGE_CACHE_SHIFT) + bh_offset(bh); | |
310 | ||
311 | io->io_bio = bio; | |
312 | io->io_op = (wbc->sync_mode == WB_SYNC_ALL ? | |
313 | WRITE_SYNC_PLUG : WRITE); | |
314 | io->io_next_block = bh->b_blocknr; | |
315 | return 0; | |
316 | } | |
317 | ||
318 | static int io_submit_add_bh(struct ext4_io_submit *io, | |
319 | struct ext4_io_page *io_page, | |
320 | struct inode *inode, | |
321 | struct writeback_control *wbc, | |
322 | struct buffer_head *bh) | |
323 | { | |
324 | ext4_io_end_t *io_end; | |
325 | int ret; | |
326 | ||
327 | if (buffer_new(bh)) { | |
328 | clear_buffer_new(bh); | |
329 | unmap_underlying_metadata(bh->b_bdev, bh->b_blocknr); | |
330 | } | |
331 | ||
332 | if (!buffer_mapped(bh) || buffer_delay(bh)) { | |
333 | if (!buffer_mapped(bh)) | |
334 | clear_buffer_dirty(bh); | |
335 | if (io->io_bio) | |
336 | ext4_io_submit(io); | |
337 | return 0; | |
338 | } | |
339 | ||
340 | if (io->io_bio && bh->b_blocknr != io->io_next_block) { | |
341 | submit_and_retry: | |
342 | ext4_io_submit(io); | |
343 | } | |
344 | if (io->io_bio == NULL) { | |
345 | ret = io_submit_init(io, inode, wbc, bh); | |
346 | if (ret) | |
347 | return ret; | |
348 | } | |
349 | io_end = io->io_end; | |
350 | if ((io_end->num_io_pages >= MAX_IO_PAGES) && | |
351 | (io_end->pages[io_end->num_io_pages-1] != io_page)) | |
352 | goto submit_and_retry; | |
353 | if (buffer_uninit(bh)) | |
354 | io->io_end->flag |= EXT4_IO_END_UNWRITTEN; | |
355 | io->io_end->size += bh->b_size; | |
356 | io->io_next_block++; | |
357 | ret = bio_add_page(io->io_bio, bh->b_page, bh->b_size, bh_offset(bh)); | |
358 | if (ret != bh->b_size) | |
359 | goto submit_and_retry; | |
360 | if ((io_end->num_io_pages == 0) || | |
361 | (io_end->pages[io_end->num_io_pages-1] != io_page)) { | |
362 | io_end->pages[io_end->num_io_pages++] = io_page; | |
363 | io_page->p_count++; | |
364 | } | |
365 | return 0; | |
366 | } | |
367 | ||
368 | int ext4_bio_write_page(struct ext4_io_submit *io, | |
369 | struct page *page, | |
370 | int len, | |
371 | struct writeback_control *wbc) | |
372 | { | |
373 | struct inode *inode = page->mapping->host; | |
374 | unsigned block_start, block_end, blocksize; | |
375 | struct ext4_io_page *io_page; | |
376 | struct buffer_head *bh, *head; | |
377 | int ret = 0; | |
378 | ||
379 | blocksize = 1 << inode->i_blkbits; | |
380 | ||
381 | BUG_ON(PageWriteback(page)); | |
382 | set_page_writeback(page); | |
383 | ClearPageError(page); | |
384 | ||
385 | io_page = kmem_cache_alloc(io_page_cachep, GFP_NOFS); | |
386 | if (!io_page) { | |
387 | set_page_dirty(page); | |
388 | unlock_page(page); | |
389 | return -ENOMEM; | |
390 | } | |
391 | io_page->p_page = page; | |
392 | io_page->p_count = 0; | |
393 | get_page(page); | |
394 | ||
395 | for (bh = head = page_buffers(page), block_start = 0; | |
396 | bh != head || !block_start; | |
397 | block_start = block_end, bh = bh->b_this_page) { | |
398 | block_end = block_start + blocksize; | |
399 | if (block_start >= len) { | |
400 | clear_buffer_dirty(bh); | |
401 | set_buffer_uptodate(bh); | |
402 | continue; | |
403 | } | |
404 | ret = io_submit_add_bh(io, io_page, inode, wbc, bh); | |
405 | if (ret) { | |
406 | /* | |
407 | * We only get here on ENOMEM. Not much else | |
408 | * we can do but mark the page as dirty, and | |
409 | * better luck next time. | |
410 | */ | |
411 | set_page_dirty(page); | |
412 | break; | |
413 | } | |
414 | } | |
415 | unlock_page(page); | |
416 | /* | |
417 | * If the page was truncated before we could do the writeback, | |
418 | * or we had a memory allocation error while trying to write | |
419 | * the first buffer head, we won't have submitted any pages for | |
420 | * I/O. In that case we need to make sure we've cleared the | |
421 | * PageWriteback bit from the page to prevent the system from | |
422 | * wedging later on. | |
423 | */ | |
424 | if (io_page->p_count == 0) { | |
425 | put_page(page); | |
426 | end_page_writeback(page); | |
427 | kmem_cache_free(io_page_cachep, io_page); | |
428 | } | |
429 | return ret; | |
430 | } |