blob: 7ce1d0b19c94576892d0d80f016f7db44110ccb7 [file] [log] [blame]
Theodore Ts'obd2d0212010-10-27 21:30:10 -04001/*
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
33static struct kmem_cache *io_page_cachep, *io_end_cachep;
34
Theodore Ts'o5dabfc72010-10-27 21:30:14 -040035int __init ext4_init_pageio(void)
Theodore Ts'obd2d0212010-10-27 21:30:10 -040036{
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);
Dan Carpenter13195182011-01-10 12:10:44 -050041 if (io_end_cachep == NULL) {
Theodore Ts'obd2d0212010-10-27 21:30:10 -040042 kmem_cache_destroy(io_page_cachep);
43 return -ENOMEM;
44 }
Theodore Ts'obd2d0212010-10-27 21:30:10 -040045 return 0;
46}
47
Theodore Ts'o5dabfc72010-10-27 21:30:14 -040048void ext4_exit_pageio(void)
Theodore Ts'obd2d0212010-10-27 21:30:10 -040049{
50 kmem_cache_destroy(io_end_cachep);
51 kmem_cache_destroy(io_page_cachep);
52}
53
Theodore Ts'of7ad6d22010-11-08 13:43:33 -050054void ext4_ioend_wait(struct inode *inode)
55{
Eric Sandeene9e3bce2011-02-12 08:17:34 -050056 wait_queue_head_t *wq = ext4_ioend_wq(inode);
Theodore Ts'of7ad6d22010-11-08 13:43:33 -050057
58 wait_event(*wq, (atomic_read(&EXT4_I(inode)->i_ioend_count) == 0));
59}
60
Theodore Ts'o83668e72010-11-08 13:45:33 -050061static void put_io_page(struct ext4_io_page *io_page)
62{
63 if (atomic_dec_and_test(&io_page->p_count)) {
64 end_page_writeback(io_page->p_page);
65 put_page(io_page->p_page);
66 kmem_cache_free(io_page_cachep, io_page);
67 }
68}
69
Theodore Ts'obd2d0212010-10-27 21:30:10 -040070void ext4_free_io_end(ext4_io_end_t *io)
71{
72 int i;
73
74 BUG_ON(!io);
75 if (io->page)
76 put_page(io->page);
Theodore Ts'o83668e72010-11-08 13:45:33 -050077 for (i = 0; i < io->num_io_pages; i++)
78 put_io_page(io->pages[i]);
Theodore Ts'obd2d0212010-10-27 21:30:10 -040079 io->num_io_pages = 0;
Theodore Ts'o4e298022011-10-30 18:41:19 -040080 if (atomic_dec_and_test(&EXT4_I(io->inode)->i_ioend_count))
81 wake_up_all(ext4_ioend_wq(io->inode));
Theodore Ts'obd2d0212010-10-27 21:30:10 -040082 kmem_cache_free(io_end_cachep, io);
83}
84
85/*
86 * check a range of space and convert unwritten extents to written.
Tao Mad73d5042011-10-30 18:26:08 -040087 *
88 * Called with inode->i_mutex; we depend on this when we manipulate
89 * io->flag, since we could otherwise race with ext4_flush_completed_IO()
Theodore Ts'obd2d0212010-10-27 21:30:10 -040090 */
91int ext4_end_io_nolock(ext4_io_end_t *io)
92{
93 struct inode *inode = io->inode;
94 loff_t offset = io->offset;
95 ssize_t size = io->size;
96 int ret = 0;
97
98 ext4_debug("ext4_end_io_nolock: io 0x%p from inode %lu,list->next 0x%p,"
99 "list->prev 0x%p\n",
100 io, inode->i_ino, io->list.next, io->list.prev);
101
Theodore Ts'obd2d0212010-10-27 21:30:10 -0400102 ret = ext4_convert_unwritten_extents(inode, offset, size);
103 if (ret < 0) {
Theodore Ts'ob82e3842011-10-31 10:56:32 -0400104 ext4_msg(inode->i_sb, KERN_EMERG,
105 "failed to convert unwritten extents to written "
106 "extents -- potential data loss! "
107 "(inode %lu, offset %llu, size %zd, error %d)",
108 inode->i_ino, offset, size, ret);
Theodore Ts'obd2d0212010-10-27 21:30:10 -0400109 }
110
111 if (io->iocb)
112 aio_complete(io->iocb, io->result, 0);
Eric Sandeene9e3bce2011-02-12 08:17:34 -0500113
Theodore Ts'ob82e3842011-10-31 10:56:32 -0400114 /* Wake up anyone waiting on unwritten extent conversion */
115 if (atomic_dec_and_test(&EXT4_I(inode)->i_aiodio_unwritten))
116 wake_up_all(ext4_ioend_wq(io->inode));
Theodore Ts'obd2d0212010-10-27 21:30:10 -0400117 return ret;
118}
119
120/*
121 * work on completed aio dio IO, to convert unwritten extents to extents
122 */
123static void ext4_end_io_work(struct work_struct *work)
124{
125 ext4_io_end_t *io = container_of(work, ext4_io_end_t, work);
126 struct inode *inode = io->inode;
127 struct ext4_inode_info *ei = EXT4_I(inode);
128 unsigned long flags;
Theodore Ts'obd2d0212010-10-27 21:30:10 -0400129
Tao Mad73d5042011-10-30 18:26:08 -0400130 spin_lock_irqsave(&ei->i_completed_io_lock, flags);
131 if (list_empty(&io->list)) {
132 spin_unlock_irqrestore(&ei->i_completed_io_lock, flags);
133 goto free;
134 }
Tao Mad73d5042011-10-30 18:26:08 -0400135
Jiaying Zhang8c0bec22011-08-31 11:50:51 -0400136 if (!mutex_trylock(&inode->i_mutex)) {
Theodore Ts'ob82e3842011-10-31 10:56:32 -0400137 spin_unlock_irqrestore(&ei->i_completed_io_lock, flags);
Jiaying Zhang8c0bec22011-08-31 11:50:51 -0400138 /*
139 * Requeue the work instead of waiting so that the work
140 * items queued after this can be processed.
141 */
142 queue_work(EXT4_SB(inode->i_sb)->dio_unwritten_wq, &io->work);
143 /*
144 * To prevent the ext4-dio-unwritten thread from keeping
145 * requeueing end_io requests and occupying cpu for too long,
146 * yield the cpu if it sees an end_io request that has already
147 * been requeued.
148 */
149 if (io->flag & EXT4_IO_END_QUEUED)
150 yield();
151 io->flag |= EXT4_IO_END_QUEUED;
152 return;
153 }
Theodore Ts'ob82e3842011-10-31 10:56:32 -0400154 list_del_init(&io->list);
Theodore Ts'obd2d0212010-10-27 21:30:10 -0400155 spin_unlock_irqrestore(&ei->i_completed_io_lock, flags);
Theodore Ts'ob82e3842011-10-31 10:56:32 -0400156 (void) ext4_end_io_nolock(io);
Theodore Ts'obd2d0212010-10-27 21:30:10 -0400157 mutex_unlock(&inode->i_mutex);
Tao Mad73d5042011-10-30 18:26:08 -0400158free:
Theodore Ts'obd2d0212010-10-27 21:30:10 -0400159 ext4_free_io_end(io);
160}
161
162ext4_io_end_t *ext4_init_io_end(struct inode *inode, gfp_t flags)
163{
Jesper Juhlb17b35e2010-12-19 21:41:55 -0500164 ext4_io_end_t *io = kmem_cache_zalloc(io_end_cachep, flags);
Theodore Ts'obd2d0212010-10-27 21:30:10 -0400165 if (io) {
Theodore Ts'of7ad6d22010-11-08 13:43:33 -0500166 atomic_inc(&EXT4_I(inode)->i_ioend_count);
167 io->inode = inode;
Theodore Ts'obd2d0212010-10-27 21:30:10 -0400168 INIT_WORK(&io->work, ext4_end_io_work);
169 INIT_LIST_HEAD(&io->list);
170 }
171 return io;
172}
173
174/*
175 * Print an buffer I/O error compatible with the fs/buffer.c. This
176 * provides compatibility with dmesg scrapers that look for a specific
177 * buffer I/O error message. We really need a unified error reporting
178 * structure to userspace ala Digital Unix's uerf system, but it's
179 * probably not going to happen in my lifetime, due to LKML politics...
180 */
181static void buffer_io_error(struct buffer_head *bh)
182{
183 char b[BDEVNAME_SIZE];
184 printk(KERN_ERR "Buffer I/O error on device %s, logical block %llu\n",
185 bdevname(bh->b_bdev, b),
186 (unsigned long long)bh->b_blocknr);
187}
188
189static void ext4_end_bio(struct bio *bio, int error)
190{
191 ext4_io_end_t *io_end = bio->bi_private;
192 struct workqueue_struct *wq;
193 struct inode *inode;
194 unsigned long flags;
Theodore Ts'obd2d0212010-10-27 21:30:10 -0400195 int i;
Curt Wohlgemuthd50bdd52011-02-07 12:46:14 -0500196 sector_t bi_sector = bio->bi_sector;
Theodore Ts'obd2d0212010-10-27 21:30:10 -0400197
198 BUG_ON(!io_end);
Theodore Ts'obd2d0212010-10-27 21:30:10 -0400199 bio->bi_private = NULL;
200 bio->bi_end_io = NULL;
201 if (test_bit(BIO_UPTODATE, &bio->bi_flags))
202 error = 0;
Theodore Ts'obd2d0212010-10-27 21:30:10 -0400203 bio_put(bio);
204
Theodore Ts'obd2d0212010-10-27 21:30:10 -0400205 for (i = 0; i < io_end->num_io_pages; i++) {
206 struct page *page = io_end->pages[i]->p_page;
207 struct buffer_head *bh, *head;
Curt Wohlgemuth39db00f2011-04-30 13:26:26 -0400208 loff_t offset;
209 loff_t io_end_offset;
Theodore Ts'obd2d0212010-10-27 21:30:10 -0400210
Curt Wohlgemuth39db00f2011-04-30 13:26:26 -0400211 if (error) {
Theodore Ts'obd2d0212010-10-27 21:30:10 -0400212 SetPageError(page);
Curt Wohlgemuth39db00f2011-04-30 13:26:26 -0400213 set_bit(AS_EIO, &page->mapping->flags);
214 head = page_buffers(page);
215 BUG_ON(!head);
216
217 io_end_offset = io_end->offset + io_end->size;
Theodore Ts'obd2d0212010-10-27 21:30:10 -0400218
219 offset = (sector_t) page->index << PAGE_CACHE_SHIFT;
220 bh = head;
221 do {
222 if ((offset >= io_end->offset) &&
Curt Wohlgemuth39db00f2011-04-30 13:26:26 -0400223 (offset+bh->b_size <= io_end_offset))
224 buffer_io_error(bh);
Theodore Ts'obd2d0212010-10-27 21:30:10 -0400225
Theodore Ts'obd2d0212010-10-27 21:30:10 -0400226 offset += bh->b_size;
227 bh = bh->b_this_page;
228 } while (bh != head);
229 }
230
Markus Trippelsdorf08da1192010-11-17 21:46:06 -0500231 put_io_page(io_end->pages[i]);
Theodore Ts'obd2d0212010-10-27 21:30:10 -0400232 }
Theodore Ts'obd2d0212010-10-27 21:30:10 -0400233 io_end->num_io_pages = 0;
Theodore Ts'of7ad6d22010-11-08 13:43:33 -0500234 inode = io_end->inode;
235
236 if (error) {
237 io_end->flag |= EXT4_IO_END_ERROR;
238 ext4_warning(inode->i_sb, "I/O error writing to inode %lu "
239 "(offset %llu size %ld starting block %llu)",
240 inode->i_ino,
241 (unsigned long long) io_end->offset,
242 (long) io_end->size,
243 (unsigned long long)
Curt Wohlgemuthd50bdd52011-02-07 12:46:14 -0500244 bi_sector >> (inode->i_blkbits - 9));
Theodore Ts'of7ad6d22010-11-08 13:43:33 -0500245 }
Theodore Ts'obd2d0212010-10-27 21:30:10 -0400246
Theodore Ts'ob6168442011-02-28 13:12:38 -0500247 if (!(io_end->flag & EXT4_IO_END_UNWRITTEN)) {
248 ext4_free_io_end(io_end);
249 return;
250 }
251
Theodore Ts'obd2d0212010-10-27 21:30:10 -0400252 /* Add the io_end to per-inode completed io list*/
253 spin_lock_irqsave(&EXT4_I(inode)->i_completed_io_lock, flags);
254 list_add_tail(&io_end->list, &EXT4_I(inode)->i_completed_io_list);
255 spin_unlock_irqrestore(&EXT4_I(inode)->i_completed_io_lock, flags);
256
257 wq = EXT4_SB(inode->i_sb)->dio_unwritten_wq;
258 /* queue the work to convert unwritten extents to written */
259 queue_work(wq, &io_end->work);
260}
261
262void ext4_io_submit(struct ext4_io_submit *io)
263{
264 struct bio *bio = io->io_bio;
265
266 if (bio) {
267 bio_get(io->io_bio);
268 submit_bio(io->io_op, io->io_bio);
269 BUG_ON(bio_flagged(io->io_bio, BIO_EOPNOTSUPP));
270 bio_put(io->io_bio);
271 }
Peter Huewe7dc57612011-02-21 21:01:42 -0500272 io->io_bio = NULL;
Theodore Ts'obd2d0212010-10-27 21:30:10 -0400273 io->io_op = 0;
Peter Huewe7dc57612011-02-21 21:01:42 -0500274 io->io_end = NULL;
Theodore Ts'obd2d0212010-10-27 21:30:10 -0400275}
276
277static int io_submit_init(struct ext4_io_submit *io,
278 struct inode *inode,
279 struct writeback_control *wbc,
280 struct buffer_head *bh)
281{
282 ext4_io_end_t *io_end;
283 struct page *page = bh->b_page;
284 int nvecs = bio_get_nr_vecs(bh->b_bdev);
285 struct bio *bio;
286
287 io_end = ext4_init_io_end(inode, GFP_NOFS);
288 if (!io_end)
289 return -ENOMEM;
Theodore Ts'o275d3ba2011-06-29 21:44:45 -0400290 bio = bio_alloc(GFP_NOIO, min(nvecs, BIO_MAX_PAGES));
Theodore Ts'obd2d0212010-10-27 21:30:10 -0400291 bio->bi_sector = bh->b_blocknr * (bh->b_size >> 9);
292 bio->bi_bdev = bh->b_bdev;
293 bio->bi_private = io->io_end = io_end;
294 bio->bi_end_io = ext4_end_bio;
295
Theodore Ts'obd2d0212010-10-27 21:30:10 -0400296 io_end->offset = (page->index << PAGE_CACHE_SHIFT) + bh_offset(bh);
297
298 io->io_bio = bio;
Jens Axboe721a9602011-03-09 11:56:30 +0100299 io->io_op = (wbc->sync_mode == WB_SYNC_ALL ? WRITE_SYNC : WRITE);
Theodore Ts'obd2d0212010-10-27 21:30:10 -0400300 io->io_next_block = bh->b_blocknr;
301 return 0;
302}
303
304static int io_submit_add_bh(struct ext4_io_submit *io,
305 struct ext4_io_page *io_page,
306 struct inode *inode,
307 struct writeback_control *wbc,
308 struct buffer_head *bh)
309{
310 ext4_io_end_t *io_end;
311 int ret;
312
313 if (buffer_new(bh)) {
314 clear_buffer_new(bh);
315 unmap_underlying_metadata(bh->b_bdev, bh->b_blocknr);
316 }
317
318 if (!buffer_mapped(bh) || buffer_delay(bh)) {
319 if (!buffer_mapped(bh))
320 clear_buffer_dirty(bh);
321 if (io->io_bio)
322 ext4_io_submit(io);
323 return 0;
324 }
325
326 if (io->io_bio && bh->b_blocknr != io->io_next_block) {
327submit_and_retry:
328 ext4_io_submit(io);
329 }
330 if (io->io_bio == NULL) {
331 ret = io_submit_init(io, inode, wbc, bh);
332 if (ret)
333 return ret;
334 }
335 io_end = io->io_end;
336 if ((io_end->num_io_pages >= MAX_IO_PAGES) &&
337 (io_end->pages[io_end->num_io_pages-1] != io_page))
338 goto submit_and_retry;
Tao Ma0edeb712011-10-31 17:30:44 -0400339 if (buffer_uninit(bh))
340 ext4_set_io_unwritten_flag(inode, io_end);
Theodore Ts'obd2d0212010-10-27 21:30:10 -0400341 io->io_end->size += bh->b_size;
342 io->io_next_block++;
343 ret = bio_add_page(io->io_bio, bh->b_page, bh->b_size, bh_offset(bh));
344 if (ret != bh->b_size)
345 goto submit_and_retry;
346 if ((io_end->num_io_pages == 0) ||
347 (io_end->pages[io_end->num_io_pages-1] != io_page)) {
348 io_end->pages[io_end->num_io_pages++] = io_page;
Theodore Ts'o83668e72010-11-08 13:45:33 -0500349 atomic_inc(&io_page->p_count);
Theodore Ts'obd2d0212010-10-27 21:30:10 -0400350 }
351 return 0;
352}
353
354int ext4_bio_write_page(struct ext4_io_submit *io,
355 struct page *page,
356 int len,
357 struct writeback_control *wbc)
358{
359 struct inode *inode = page->mapping->host;
360 unsigned block_start, block_end, blocksize;
361 struct ext4_io_page *io_page;
362 struct buffer_head *bh, *head;
363 int ret = 0;
364
365 blocksize = 1 << inode->i_blkbits;
366
Curt Wohlgemuthd50bdd52011-02-07 12:46:14 -0500367 BUG_ON(!PageLocked(page));
Theodore Ts'obd2d0212010-10-27 21:30:10 -0400368 BUG_ON(PageWriteback(page));
Theodore Ts'obd2d0212010-10-27 21:30:10 -0400369
370 io_page = kmem_cache_alloc(io_page_cachep, GFP_NOFS);
371 if (!io_page) {
372 set_page_dirty(page);
373 unlock_page(page);
374 return -ENOMEM;
375 }
376 io_page->p_page = page;
Theodore Ts'o83668e72010-11-08 13:45:33 -0500377 atomic_set(&io_page->p_count, 1);
Theodore Ts'obd2d0212010-10-27 21:30:10 -0400378 get_page(page);
Theodore Ts'oa54aa762011-02-27 16:43:24 -0500379 set_page_writeback(page);
380 ClearPageError(page);
Theodore Ts'obd2d0212010-10-27 21:30:10 -0400381
382 for (bh = head = page_buffers(page), block_start = 0;
383 bh != head || !block_start;
384 block_start = block_end, bh = bh->b_this_page) {
Curt Wohlgemuthd50bdd52011-02-07 12:46:14 -0500385
Theodore Ts'obd2d0212010-10-27 21:30:10 -0400386 block_end = block_start + blocksize;
387 if (block_start >= len) {
388 clear_buffer_dirty(bh);
389 set_buffer_uptodate(bh);
390 continue;
391 }
Curt Wohlgemuthd50bdd52011-02-07 12:46:14 -0500392 clear_buffer_dirty(bh);
Theodore Ts'obd2d0212010-10-27 21:30:10 -0400393 ret = io_submit_add_bh(io, io_page, inode, wbc, bh);
394 if (ret) {
395 /*
396 * We only get here on ENOMEM. Not much else
397 * we can do but mark the page as dirty, and
398 * better luck next time.
399 */
400 set_page_dirty(page);
401 break;
402 }
403 }
404 unlock_page(page);
405 /*
406 * If the page was truncated before we could do the writeback,
407 * or we had a memory allocation error while trying to write
408 * the first buffer head, we won't have submitted any pages for
409 * I/O. In that case we need to make sure we've cleared the
410 * PageWriteback bit from the page to prevent the system from
411 * wedging later on.
412 */
Theodore Ts'o83668e72010-11-08 13:45:33 -0500413 put_io_page(io_page);
Theodore Ts'obd2d0212010-10-27 21:30:10 -0400414 return ret;
415}