Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/linville/wirel...
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / fs / ext4 / page-io.c
blobb6dbd056fcb1d7f532f428e34cae4ef5248680ce
1 /*
2 * linux/fs/ext4/page-io.c
4 * This contains the new page_io functions for ext4
6 * Written by Theodore Ts'o, 2010.
7 */
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>
28 #include "ext4_jbd2.h"
29 #include "xattr.h"
30 #include "acl.h"
31 #include "ext4_extents.h"
33 static struct kmem_cache *io_page_cachep, *io_end_cachep;
35 int __init ext4_init_pageio(void)
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_end_cachep == NULL) {
42 kmem_cache_destroy(io_page_cachep);
43 return -ENOMEM;
45 return 0;
48 void ext4_exit_pageio(void)
50 kmem_cache_destroy(io_end_cachep);
51 kmem_cache_destroy(io_page_cachep);
54 void ext4_ioend_wait(struct inode *inode)
56 wait_queue_head_t *wq = ext4_ioend_wq(inode);
58 wait_event(*wq, (atomic_read(&EXT4_I(inode)->i_ioend_count) == 0));
61 static void put_io_page(struct ext4_io_page *io_page)
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);
70 void ext4_free_io_end(ext4_io_end_t *io)
72 int i;
73 wait_queue_head_t *wq;
75 BUG_ON(!io);
76 if (io->page)
77 put_page(io->page);
78 for (i = 0; i < io->num_io_pages; i++)
79 put_io_page(io->pages[i]);
80 io->num_io_pages = 0;
81 wq = ext4_ioend_wq(io->inode);
82 if (atomic_dec_and_test(&EXT4_I(io->inode)->i_ioend_count) &&
83 waitqueue_active(wq))
84 wake_up_all(wq);
85 kmem_cache_free(io_end_cachep, io);
89 * check a range of space and convert unwritten extents to written.
91 int ext4_end_io_nolock(ext4_io_end_t *io)
93 struct inode *inode = io->inode;
94 loff_t offset = io->offset;
95 ssize_t size = io->size;
96 wait_queue_head_t *wq;
97 int ret = 0;
99 ext4_debug("ext4_end_io_nolock: io 0x%p from inode %lu,list->next 0x%p,"
100 "list->prev 0x%p\n",
101 io, inode->i_ino, io->list.next, io->list.prev);
103 if (list_empty(&io->list))
104 return ret;
106 if (!(io->flag & EXT4_IO_END_UNWRITTEN))
107 return ret;
109 ret = ext4_convert_unwritten_extents(inode, offset, size);
110 if (ret < 0) {
111 printk(KERN_EMERG "%s: failed to convert unwritten "
112 "extents to written extents, error is %d "
113 "io is still on inode %lu aio dio list\n",
114 __func__, ret, inode->i_ino);
115 return ret;
118 if (io->iocb)
119 aio_complete(io->iocb, io->result, 0);
120 /* clear the DIO AIO unwritten flag */
121 if (io->flag & EXT4_IO_END_UNWRITTEN) {
122 io->flag &= ~EXT4_IO_END_UNWRITTEN;
123 /* Wake up anyone waiting on unwritten extent conversion */
124 wq = ext4_ioend_wq(io->inode);
125 if (atomic_dec_and_test(&EXT4_I(inode)->i_aiodio_unwritten) &&
126 waitqueue_active(wq)) {
127 wake_up_all(wq);
131 return ret;
135 * work on completed aio dio IO, to convert unwritten extents to extents
137 static void ext4_end_io_work(struct work_struct *work)
139 ext4_io_end_t *io = container_of(work, ext4_io_end_t, work);
140 struct inode *inode = io->inode;
141 struct ext4_inode_info *ei = EXT4_I(inode);
142 unsigned long flags;
143 int ret;
145 mutex_lock(&inode->i_mutex);
146 ret = ext4_end_io_nolock(io);
147 if (ret < 0) {
148 mutex_unlock(&inode->i_mutex);
149 return;
152 spin_lock_irqsave(&ei->i_completed_io_lock, flags);
153 if (!list_empty(&io->list))
154 list_del_init(&io->list);
155 spin_unlock_irqrestore(&ei->i_completed_io_lock, flags);
156 mutex_unlock(&inode->i_mutex);
157 ext4_free_io_end(io);
160 ext4_io_end_t *ext4_init_io_end(struct inode *inode, gfp_t flags)
162 ext4_io_end_t *io = kmem_cache_zalloc(io_end_cachep, flags);
163 if (io) {
164 atomic_inc(&EXT4_I(inode)->i_ioend_count);
165 io->inode = inode;
166 INIT_WORK(&io->work, ext4_end_io_work);
167 INIT_LIST_HEAD(&io->list);
169 return io;
173 * Print an buffer I/O error compatible with the fs/buffer.c. This
174 * provides compatibility with dmesg scrapers that look for a specific
175 * buffer I/O error message. We really need a unified error reporting
176 * structure to userspace ala Digital Unix's uerf system, but it's
177 * probably not going to happen in my lifetime, due to LKML politics...
179 static void buffer_io_error(struct buffer_head *bh)
181 char b[BDEVNAME_SIZE];
182 printk(KERN_ERR "Buffer I/O error on device %s, logical block %llu\n",
183 bdevname(bh->b_bdev, b),
184 (unsigned long long)bh->b_blocknr);
187 static void ext4_end_bio(struct bio *bio, int error)
189 ext4_io_end_t *io_end = bio->bi_private;
190 struct workqueue_struct *wq;
191 struct inode *inode;
192 unsigned long flags;
193 int i;
194 sector_t bi_sector = bio->bi_sector;
196 BUG_ON(!io_end);
197 bio->bi_private = NULL;
198 bio->bi_end_io = NULL;
199 if (test_bit(BIO_UPTODATE, &bio->bi_flags))
200 error = 0;
201 bio_put(bio);
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;
208 head = page_buffers(page);
209 if (error)
210 SetPageError(page);
211 BUG_ON(!head);
212 if (head->b_size != PAGE_CACHE_SIZE) {
213 loff_t offset;
214 loff_t io_end_offset = io_end->offset + io_end->size;
216 offset = (sector_t) page->index << PAGE_CACHE_SHIFT;
217 bh = head;
218 do {
219 if ((offset >= io_end->offset) &&
220 (offset+bh->b_size <= io_end_offset)) {
221 if (error)
222 buffer_io_error(bh);
225 if (buffer_delay(bh))
226 partial_write = 1;
227 else if (!buffer_mapped(bh))
228 clear_buffer_dirty(bh);
229 else if (buffer_dirty(bh))
230 partial_write = 1;
231 offset += bh->b_size;
232 bh = bh->b_this_page;
233 } while (bh != head);
237 * If this is a partial write which happened to make
238 * all buffers uptodate then we can optimize away a
239 * bogus readpage() for the next read(). Here we
240 * 'discover' whether the page went uptodate as a
241 * result of this (potentially partial) write.
243 if (!partial_write)
244 SetPageUptodate(page);
246 put_io_page(io_end->pages[i]);
248 io_end->num_io_pages = 0;
249 inode = io_end->inode;
251 if (error) {
252 io_end->flag |= EXT4_IO_END_ERROR;
253 ext4_warning(inode->i_sb, "I/O error writing to inode %lu "
254 "(offset %llu size %ld starting block %llu)",
255 inode->i_ino,
256 (unsigned long long) io_end->offset,
257 (long) io_end->size,
258 (unsigned long long)
259 bi_sector >> (inode->i_blkbits - 9));
262 if (!(io_end->flag & EXT4_IO_END_UNWRITTEN)) {
263 ext4_free_io_end(io_end);
264 return;
267 /* Add the io_end to per-inode completed io list*/
268 spin_lock_irqsave(&EXT4_I(inode)->i_completed_io_lock, flags);
269 list_add_tail(&io_end->list, &EXT4_I(inode)->i_completed_io_list);
270 spin_unlock_irqrestore(&EXT4_I(inode)->i_completed_io_lock, flags);
272 wq = EXT4_SB(inode->i_sb)->dio_unwritten_wq;
273 /* queue the work to convert unwritten extents to written */
274 queue_work(wq, &io_end->work);
277 void ext4_io_submit(struct ext4_io_submit *io)
279 struct bio *bio = io->io_bio;
281 if (bio) {
282 bio_get(io->io_bio);
283 submit_bio(io->io_op, io->io_bio);
284 BUG_ON(bio_flagged(io->io_bio, BIO_EOPNOTSUPP));
285 bio_put(io->io_bio);
287 io->io_bio = NULL;
288 io->io_op = 0;
289 io->io_end = NULL;
292 static int io_submit_init(struct ext4_io_submit *io,
293 struct inode *inode,
294 struct writeback_control *wbc,
295 struct buffer_head *bh)
297 ext4_io_end_t *io_end;
298 struct page *page = bh->b_page;
299 int nvecs = bio_get_nr_vecs(bh->b_bdev);
300 struct bio *bio;
302 io_end = ext4_init_io_end(inode, GFP_NOFS);
303 if (!io_end)
304 return -ENOMEM;
305 do {
306 bio = bio_alloc(GFP_NOIO, nvecs);
307 nvecs >>= 1;
308 } while (bio == NULL);
310 bio->bi_sector = bh->b_blocknr * (bh->b_size >> 9);
311 bio->bi_bdev = bh->b_bdev;
312 bio->bi_private = io->io_end = io_end;
313 bio->bi_end_io = ext4_end_bio;
315 io_end->offset = (page->index << PAGE_CACHE_SHIFT) + bh_offset(bh);
317 io->io_bio = bio;
318 io->io_op = (wbc->sync_mode == WB_SYNC_ALL ? WRITE_SYNC : WRITE);
319 io->io_next_block = bh->b_blocknr;
320 return 0;
323 static int io_submit_add_bh(struct ext4_io_submit *io,
324 struct ext4_io_page *io_page,
325 struct inode *inode,
326 struct writeback_control *wbc,
327 struct buffer_head *bh)
329 ext4_io_end_t *io_end;
330 int ret;
332 if (buffer_new(bh)) {
333 clear_buffer_new(bh);
334 unmap_underlying_metadata(bh->b_bdev, bh->b_blocknr);
337 if (!buffer_mapped(bh) || buffer_delay(bh)) {
338 if (!buffer_mapped(bh))
339 clear_buffer_dirty(bh);
340 if (io->io_bio)
341 ext4_io_submit(io);
342 return 0;
345 if (io->io_bio && bh->b_blocknr != io->io_next_block) {
346 submit_and_retry:
347 ext4_io_submit(io);
349 if (io->io_bio == NULL) {
350 ret = io_submit_init(io, inode, wbc, bh);
351 if (ret)
352 return ret;
354 io_end = io->io_end;
355 if ((io_end->num_io_pages >= MAX_IO_PAGES) &&
356 (io_end->pages[io_end->num_io_pages-1] != io_page))
357 goto submit_and_retry;
358 if (buffer_uninit(bh))
359 io->io_end->flag |= EXT4_IO_END_UNWRITTEN;
360 io->io_end->size += bh->b_size;
361 io->io_next_block++;
362 ret = bio_add_page(io->io_bio, bh->b_page, bh->b_size, bh_offset(bh));
363 if (ret != bh->b_size)
364 goto submit_and_retry;
365 if ((io_end->num_io_pages == 0) ||
366 (io_end->pages[io_end->num_io_pages-1] != io_page)) {
367 io_end->pages[io_end->num_io_pages++] = io_page;
368 atomic_inc(&io_page->p_count);
370 return 0;
373 int ext4_bio_write_page(struct ext4_io_submit *io,
374 struct page *page,
375 int len,
376 struct writeback_control *wbc)
378 struct inode *inode = page->mapping->host;
379 unsigned block_start, block_end, blocksize;
380 struct ext4_io_page *io_page;
381 struct buffer_head *bh, *head;
382 int ret = 0;
384 blocksize = 1 << inode->i_blkbits;
386 BUG_ON(!PageLocked(page));
387 BUG_ON(PageWriteback(page));
389 io_page = kmem_cache_alloc(io_page_cachep, GFP_NOFS);
390 if (!io_page) {
391 set_page_dirty(page);
392 unlock_page(page);
393 return -ENOMEM;
395 io_page->p_page = page;
396 atomic_set(&io_page->p_count, 1);
397 get_page(page);
398 set_page_writeback(page);
399 ClearPageError(page);
401 for (bh = head = page_buffers(page), block_start = 0;
402 bh != head || !block_start;
403 block_start = block_end, bh = bh->b_this_page) {
405 block_end = block_start + blocksize;
406 if (block_start >= len) {
407 clear_buffer_dirty(bh);
408 set_buffer_uptodate(bh);
409 continue;
411 clear_buffer_dirty(bh);
412 ret = io_submit_add_bh(io, io_page, inode, wbc, bh);
413 if (ret) {
415 * We only get here on ENOMEM. Not much else
416 * we can do but mark the page as dirty, and
417 * better luck next time.
419 set_page_dirty(page);
420 break;
423 unlock_page(page);
425 * If the page was truncated before we could do the writeback,
426 * or we had a memory allocation error while trying to write
427 * the first buffer head, we won't have submitted any pages for
428 * I/O. In that case we need to make sure we've cleared the
429 * PageWriteback bit from the page to prevent the system from
430 * wedging later on.
432 put_io_page(io_page);
433 return ret;