Merge branch 'topic/hda-gateway' into topic/hda
[linux-2.6] / fs / ocfs2 / aops.c
1 /* -*- mode: c; c-basic-offset: 8; -*-
2  * vim: noexpandtab sw=8 ts=8 sts=0:
3  *
4  * Copyright (C) 2002, 2004 Oracle.  All rights reserved.
5  *
6  * This program is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU General Public
8  * License as published by the Free Software Foundation; either
9  * version 2 of the License, or (at your option) any later version.
10  *
11  * This program is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
14  * General Public License for more details.
15  *
16  * You should have received a copy of the GNU General Public
17  * License along with this program; if not, write to the
18  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
19  * Boston, MA 021110-1307, USA.
20  */
21
22 #include <linux/fs.h>
23 #include <linux/slab.h>
24 #include <linux/highmem.h>
25 #include <linux/pagemap.h>
26 #include <asm/byteorder.h>
27 #include <linux/swap.h>
28 #include <linux/pipe_fs_i.h>
29 #include <linux/mpage.h>
30 #include <linux/quotaops.h>
31
32 #define MLOG_MASK_PREFIX ML_FILE_IO
33 #include <cluster/masklog.h>
34
35 #include "ocfs2.h"
36
37 #include "alloc.h"
38 #include "aops.h"
39 #include "dlmglue.h"
40 #include "extent_map.h"
41 #include "file.h"
42 #include "inode.h"
43 #include "journal.h"
44 #include "suballoc.h"
45 #include "super.h"
46 #include "symlink.h"
47
48 #include "buffer_head_io.h"
49
50 static int ocfs2_symlink_get_block(struct inode *inode, sector_t iblock,
51                                    struct buffer_head *bh_result, int create)
52 {
53         int err = -EIO;
54         int status;
55         struct ocfs2_dinode *fe = NULL;
56         struct buffer_head *bh = NULL;
57         struct buffer_head *buffer_cache_bh = NULL;
58         struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
59         void *kaddr;
60
61         mlog_entry("(0x%p, %llu, 0x%p, %d)\n", inode,
62                    (unsigned long long)iblock, bh_result, create);
63
64         BUG_ON(ocfs2_inode_is_fast_symlink(inode));
65
66         if ((iblock << inode->i_sb->s_blocksize_bits) > PATH_MAX + 1) {
67                 mlog(ML_ERROR, "block offset > PATH_MAX: %llu",
68                      (unsigned long long)iblock);
69                 goto bail;
70         }
71
72         status = ocfs2_read_inode_block(inode, &bh);
73         if (status < 0) {
74                 mlog_errno(status);
75                 goto bail;
76         }
77         fe = (struct ocfs2_dinode *) bh->b_data;
78
79         if ((u64)iblock >= ocfs2_clusters_to_blocks(inode->i_sb,
80                                                     le32_to_cpu(fe->i_clusters))) {
81                 mlog(ML_ERROR, "block offset is outside the allocated size: "
82                      "%llu\n", (unsigned long long)iblock);
83                 goto bail;
84         }
85
86         /* We don't use the page cache to create symlink data, so if
87          * need be, copy it over from the buffer cache. */
88         if (!buffer_uptodate(bh_result) && ocfs2_inode_is_new(inode)) {
89                 u64 blkno = le64_to_cpu(fe->id2.i_list.l_recs[0].e_blkno) +
90                             iblock;
91                 buffer_cache_bh = sb_getblk(osb->sb, blkno);
92                 if (!buffer_cache_bh) {
93                         mlog(ML_ERROR, "couldn't getblock for symlink!\n");
94                         goto bail;
95                 }
96
97                 /* we haven't locked out transactions, so a commit
98                  * could've happened. Since we've got a reference on
99                  * the bh, even if it commits while we're doing the
100                  * copy, the data is still good. */
101                 if (buffer_jbd(buffer_cache_bh)
102                     && ocfs2_inode_is_new(inode)) {
103                         kaddr = kmap_atomic(bh_result->b_page, KM_USER0);
104                         if (!kaddr) {
105                                 mlog(ML_ERROR, "couldn't kmap!\n");
106                                 goto bail;
107                         }
108                         memcpy(kaddr + (bh_result->b_size * iblock),
109                                buffer_cache_bh->b_data,
110                                bh_result->b_size);
111                         kunmap_atomic(kaddr, KM_USER0);
112                         set_buffer_uptodate(bh_result);
113                 }
114                 brelse(buffer_cache_bh);
115         }
116
117         map_bh(bh_result, inode->i_sb,
118                le64_to_cpu(fe->id2.i_list.l_recs[0].e_blkno) + iblock);
119
120         err = 0;
121
122 bail:
123         brelse(bh);
124
125         mlog_exit(err);
126         return err;
127 }
128
129 static int ocfs2_get_block(struct inode *inode, sector_t iblock,
130                            struct buffer_head *bh_result, int create)
131 {
132         int err = 0;
133         unsigned int ext_flags;
134         u64 max_blocks = bh_result->b_size >> inode->i_blkbits;
135         u64 p_blkno, count, past_eof;
136         struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
137
138         mlog_entry("(0x%p, %llu, 0x%p, %d)\n", inode,
139                    (unsigned long long)iblock, bh_result, create);
140
141         if (OCFS2_I(inode)->ip_flags & OCFS2_INODE_SYSTEM_FILE)
142                 mlog(ML_NOTICE, "get_block on system inode 0x%p (%lu)\n",
143                      inode, inode->i_ino);
144
145         if (S_ISLNK(inode->i_mode)) {
146                 /* this always does I/O for some reason. */
147                 err = ocfs2_symlink_get_block(inode, iblock, bh_result, create);
148                 goto bail;
149         }
150
151         err = ocfs2_extent_map_get_blocks(inode, iblock, &p_blkno, &count,
152                                           &ext_flags);
153         if (err) {
154                 mlog(ML_ERROR, "Error %d from get_blocks(0x%p, %llu, 1, "
155                      "%llu, NULL)\n", err, inode, (unsigned long long)iblock,
156                      (unsigned long long)p_blkno);
157                 goto bail;
158         }
159
160         if (max_blocks < count)
161                 count = max_blocks;
162
163         /*
164          * ocfs2 never allocates in this function - the only time we
165          * need to use BH_New is when we're extending i_size on a file
166          * system which doesn't support holes, in which case BH_New
167          * allows block_prepare_write() to zero.
168          *
169          * If we see this on a sparse file system, then a truncate has
170          * raced us and removed the cluster. In this case, we clear
171          * the buffers dirty and uptodate bits and let the buffer code
172          * ignore it as a hole.
173          */
174         if (create && p_blkno == 0 && ocfs2_sparse_alloc(osb)) {
175                 clear_buffer_dirty(bh_result);
176                 clear_buffer_uptodate(bh_result);
177                 goto bail;
178         }
179
180         /* Treat the unwritten extent as a hole for zeroing purposes. */
181         if (p_blkno && !(ext_flags & OCFS2_EXT_UNWRITTEN))
182                 map_bh(bh_result, inode->i_sb, p_blkno);
183
184         bh_result->b_size = count << inode->i_blkbits;
185
186         if (!ocfs2_sparse_alloc(osb)) {
187                 if (p_blkno == 0) {
188                         err = -EIO;
189                         mlog(ML_ERROR,
190                              "iblock = %llu p_blkno = %llu blkno=(%llu)\n",
191                              (unsigned long long)iblock,
192                              (unsigned long long)p_blkno,
193                              (unsigned long long)OCFS2_I(inode)->ip_blkno);
194                         mlog(ML_ERROR, "Size %llu, clusters %u\n", (unsigned long long)i_size_read(inode), OCFS2_I(inode)->ip_clusters);
195                         dump_stack();
196                 }
197
198                 past_eof = ocfs2_blocks_for_bytes(inode->i_sb, i_size_read(inode));
199                 mlog(0, "Inode %lu, past_eof = %llu\n", inode->i_ino,
200                      (unsigned long long)past_eof);
201
202                 if (create && (iblock >= past_eof))
203                         set_buffer_new(bh_result);
204         }
205
206 bail:
207         if (err < 0)
208                 err = -EIO;
209
210         mlog_exit(err);
211         return err;
212 }
213
214 int ocfs2_read_inline_data(struct inode *inode, struct page *page,
215                            struct buffer_head *di_bh)
216 {
217         void *kaddr;
218         loff_t size;
219         struct ocfs2_dinode *di = (struct ocfs2_dinode *)di_bh->b_data;
220
221         if (!(le16_to_cpu(di->i_dyn_features) & OCFS2_INLINE_DATA_FL)) {
222                 ocfs2_error(inode->i_sb, "Inode %llu lost inline data flag",
223                             (unsigned long long)OCFS2_I(inode)->ip_blkno);
224                 return -EROFS;
225         }
226
227         size = i_size_read(inode);
228
229         if (size > PAGE_CACHE_SIZE ||
230             size > ocfs2_max_inline_data(inode->i_sb)) {
231                 ocfs2_error(inode->i_sb,
232                             "Inode %llu has with inline data has bad size: %Lu",
233                             (unsigned long long)OCFS2_I(inode)->ip_blkno,
234                             (unsigned long long)size);
235                 return -EROFS;
236         }
237
238         kaddr = kmap_atomic(page, KM_USER0);
239         if (size)
240                 memcpy(kaddr, di->id2.i_data.id_data, size);
241         /* Clear the remaining part of the page */
242         memset(kaddr + size, 0, PAGE_CACHE_SIZE - size);
243         flush_dcache_page(page);
244         kunmap_atomic(kaddr, KM_USER0);
245
246         SetPageUptodate(page);
247
248         return 0;
249 }
250
251 static int ocfs2_readpage_inline(struct inode *inode, struct page *page)
252 {
253         int ret;
254         struct buffer_head *di_bh = NULL;
255
256         BUG_ON(!PageLocked(page));
257         BUG_ON(!(OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL));
258
259         ret = ocfs2_read_inode_block(inode, &di_bh);
260         if (ret) {
261                 mlog_errno(ret);
262                 goto out;
263         }
264
265         ret = ocfs2_read_inline_data(inode, page, di_bh);
266 out:
267         unlock_page(page);
268
269         brelse(di_bh);
270         return ret;
271 }
272
273 static int ocfs2_readpage(struct file *file, struct page *page)
274 {
275         struct inode *inode = page->mapping->host;
276         struct ocfs2_inode_info *oi = OCFS2_I(inode);
277         loff_t start = (loff_t)page->index << PAGE_CACHE_SHIFT;
278         int ret, unlock = 1;
279
280         mlog_entry("(0x%p, %lu)\n", file, (page ? page->index : 0));
281
282         ret = ocfs2_inode_lock_with_page(inode, NULL, 0, page);
283         if (ret != 0) {
284                 if (ret == AOP_TRUNCATED_PAGE)
285                         unlock = 0;
286                 mlog_errno(ret);
287                 goto out;
288         }
289
290         if (down_read_trylock(&oi->ip_alloc_sem) == 0) {
291                 ret = AOP_TRUNCATED_PAGE;
292                 goto out_inode_unlock;
293         }
294
295         /*
296          * i_size might have just been updated as we grabed the meta lock.  We
297          * might now be discovering a truncate that hit on another node.
298          * block_read_full_page->get_block freaks out if it is asked to read
299          * beyond the end of a file, so we check here.  Callers
300          * (generic_file_read, vm_ops->fault) are clever enough to check i_size
301          * and notice that the page they just read isn't needed.
302          *
303          * XXX sys_readahead() seems to get that wrong?
304          */
305         if (start >= i_size_read(inode)) {
306                 zero_user(page, 0, PAGE_SIZE);
307                 SetPageUptodate(page);
308                 ret = 0;
309                 goto out_alloc;
310         }
311
312         if (oi->ip_dyn_features & OCFS2_INLINE_DATA_FL)
313                 ret = ocfs2_readpage_inline(inode, page);
314         else
315                 ret = block_read_full_page(page, ocfs2_get_block);
316         unlock = 0;
317
318 out_alloc:
319         up_read(&OCFS2_I(inode)->ip_alloc_sem);
320 out_inode_unlock:
321         ocfs2_inode_unlock(inode, 0);
322 out:
323         if (unlock)
324                 unlock_page(page);
325         mlog_exit(ret);
326         return ret;
327 }
328
329 /*
330  * This is used only for read-ahead. Failures or difficult to handle
331  * situations are safe to ignore.
332  *
333  * Right now, we don't bother with BH_Boundary - in-inode extent lists
334  * are quite large (243 extents on 4k blocks), so most inodes don't
335  * grow out to a tree. If need be, detecting boundary extents could
336  * trivially be added in a future version of ocfs2_get_block().
337  */
338 static int ocfs2_readpages(struct file *filp, struct address_space *mapping,
339                            struct list_head *pages, unsigned nr_pages)
340 {
341         int ret, err = -EIO;
342         struct inode *inode = mapping->host;
343         struct ocfs2_inode_info *oi = OCFS2_I(inode);
344         loff_t start;
345         struct page *last;
346
347         /*
348          * Use the nonblocking flag for the dlm code to avoid page
349          * lock inversion, but don't bother with retrying.
350          */
351         ret = ocfs2_inode_lock_full(inode, NULL, 0, OCFS2_LOCK_NONBLOCK);
352         if (ret)
353                 return err;
354
355         if (down_read_trylock(&oi->ip_alloc_sem) == 0) {
356                 ocfs2_inode_unlock(inode, 0);
357                 return err;
358         }
359
360         /*
361          * Don't bother with inline-data. There isn't anything
362          * to read-ahead in that case anyway...
363          */
364         if (oi->ip_dyn_features & OCFS2_INLINE_DATA_FL)
365                 goto out_unlock;
366
367         /*
368          * Check whether a remote node truncated this file - we just
369          * drop out in that case as it's not worth handling here.
370          */
371         last = list_entry(pages->prev, struct page, lru);
372         start = (loff_t)last->index << PAGE_CACHE_SHIFT;
373         if (start >= i_size_read(inode))
374                 goto out_unlock;
375
376         err = mpage_readpages(mapping, pages, nr_pages, ocfs2_get_block);
377
378 out_unlock:
379         up_read(&oi->ip_alloc_sem);
380         ocfs2_inode_unlock(inode, 0);
381
382         return err;
383 }
384
385 /* Note: Because we don't support holes, our allocation has
386  * already happened (allocation writes zeros to the file data)
387  * so we don't have to worry about ordered writes in
388  * ocfs2_writepage.
389  *
390  * ->writepage is called during the process of invalidating the page cache
391  * during blocked lock processing.  It can't block on any cluster locks
392  * to during block mapping.  It's relying on the fact that the block
393  * mapping can't have disappeared under the dirty pages that it is
394  * being asked to write back.
395  */
396 static int ocfs2_writepage(struct page *page, struct writeback_control *wbc)
397 {
398         int ret;
399
400         mlog_entry("(0x%p)\n", page);
401
402         ret = block_write_full_page(page, ocfs2_get_block, wbc);
403
404         mlog_exit(ret);
405
406         return ret;
407 }
408
409 /*
410  * This is called from ocfs2_write_zero_page() which has handled it's
411  * own cluster locking and has ensured allocation exists for those
412  * blocks to be written.
413  */
414 int ocfs2_prepare_write_nolock(struct inode *inode, struct page *page,
415                                unsigned from, unsigned to)
416 {
417         int ret;
418
419         ret = block_prepare_write(page, from, to, ocfs2_get_block);
420
421         return ret;
422 }
423
424 /* Taken from ext3. We don't necessarily need the full blown
425  * functionality yet, but IMHO it's better to cut and paste the whole
426  * thing so we can avoid introducing our own bugs (and easily pick up
427  * their fixes when they happen) --Mark */
428 int walk_page_buffers(  handle_t *handle,
429                         struct buffer_head *head,
430                         unsigned from,
431                         unsigned to,
432                         int *partial,
433                         int (*fn)(      handle_t *handle,
434                                         struct buffer_head *bh))
435 {
436         struct buffer_head *bh;
437         unsigned block_start, block_end;
438         unsigned blocksize = head->b_size;
439         int err, ret = 0;
440         struct buffer_head *next;
441
442         for (   bh = head, block_start = 0;
443                 ret == 0 && (bh != head || !block_start);
444                 block_start = block_end, bh = next)
445         {
446                 next = bh->b_this_page;
447                 block_end = block_start + blocksize;
448                 if (block_end <= from || block_start >= to) {
449                         if (partial && !buffer_uptodate(bh))
450                                 *partial = 1;
451                         continue;
452                 }
453                 err = (*fn)(handle, bh);
454                 if (!ret)
455                         ret = err;
456         }
457         return ret;
458 }
459
460 handle_t *ocfs2_start_walk_page_trans(struct inode *inode,
461                                                          struct page *page,
462                                                          unsigned from,
463                                                          unsigned to)
464 {
465         struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
466         handle_t *handle;
467         int ret = 0;
468
469         handle = ocfs2_start_trans(osb, OCFS2_INODE_UPDATE_CREDITS);
470         if (IS_ERR(handle)) {
471                 ret = -ENOMEM;
472                 mlog_errno(ret);
473                 goto out;
474         }
475
476         if (ocfs2_should_order_data(inode)) {
477                 ret = ocfs2_jbd2_file_inode(handle, inode);
478                 if (ret < 0)
479                         mlog_errno(ret);
480         }
481 out:
482         if (ret) {
483                 if (!IS_ERR(handle))
484                         ocfs2_commit_trans(osb, handle);
485                 handle = ERR_PTR(ret);
486         }
487         return handle;
488 }
489
490 static sector_t ocfs2_bmap(struct address_space *mapping, sector_t block)
491 {
492         sector_t status;
493         u64 p_blkno = 0;
494         int err = 0;
495         struct inode *inode = mapping->host;
496
497         mlog_entry("(block = %llu)\n", (unsigned long long)block);
498
499         /* We don't need to lock journal system files, since they aren't
500          * accessed concurrently from multiple nodes.
501          */
502         if (!INODE_JOURNAL(inode)) {
503                 err = ocfs2_inode_lock(inode, NULL, 0);
504                 if (err) {
505                         if (err != -ENOENT)
506                                 mlog_errno(err);
507                         goto bail;
508                 }
509                 down_read(&OCFS2_I(inode)->ip_alloc_sem);
510         }
511
512         if (!(OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL))
513                 err = ocfs2_extent_map_get_blocks(inode, block, &p_blkno, NULL,
514                                                   NULL);
515
516         if (!INODE_JOURNAL(inode)) {
517                 up_read(&OCFS2_I(inode)->ip_alloc_sem);
518                 ocfs2_inode_unlock(inode, 0);
519         }
520
521         if (err) {
522                 mlog(ML_ERROR, "get_blocks() failed, block = %llu\n",
523                      (unsigned long long)block);
524                 mlog_errno(err);
525                 goto bail;
526         }
527
528 bail:
529         status = err ? 0 : p_blkno;
530
531         mlog_exit((int)status);
532
533         return status;
534 }
535
536 /*
537  * TODO: Make this into a generic get_blocks function.
538  *
539  * From do_direct_io in direct-io.c:
540  *  "So what we do is to permit the ->get_blocks function to populate
541  *   bh.b_size with the size of IO which is permitted at this offset and
542  *   this i_blkbits."
543  *
544  * This function is called directly from get_more_blocks in direct-io.c.
545  *
546  * called like this: dio->get_blocks(dio->inode, fs_startblk,
547  *                                      fs_count, map_bh, dio->rw == WRITE);
548  */
549 static int ocfs2_direct_IO_get_blocks(struct inode *inode, sector_t iblock,
550                                      struct buffer_head *bh_result, int create)
551 {
552         int ret;
553         u64 p_blkno, inode_blocks, contig_blocks;
554         unsigned int ext_flags;
555         unsigned char blocksize_bits = inode->i_sb->s_blocksize_bits;
556         unsigned long max_blocks = bh_result->b_size >> inode->i_blkbits;
557
558         /* This function won't even be called if the request isn't all
559          * nicely aligned and of the right size, so there's no need
560          * for us to check any of that. */
561
562         inode_blocks = ocfs2_blocks_for_bytes(inode->i_sb, i_size_read(inode));
563
564         /*
565          * Any write past EOF is not allowed because we'd be extending.
566          */
567         if (create && (iblock + max_blocks) > inode_blocks) {
568                 ret = -EIO;
569                 goto bail;
570         }
571
572         /* This figures out the size of the next contiguous block, and
573          * our logical offset */
574         ret = ocfs2_extent_map_get_blocks(inode, iblock, &p_blkno,
575                                           &contig_blocks, &ext_flags);
576         if (ret) {
577                 mlog(ML_ERROR, "get_blocks() failed iblock=%llu\n",
578                      (unsigned long long)iblock);
579                 ret = -EIO;
580                 goto bail;
581         }
582
583         if (!ocfs2_sparse_alloc(OCFS2_SB(inode->i_sb)) && !p_blkno && create) {
584                 ocfs2_error(inode->i_sb,
585                             "Inode %llu has a hole at block %llu\n",
586                             (unsigned long long)OCFS2_I(inode)->ip_blkno,
587                             (unsigned long long)iblock);
588                 ret = -EROFS;
589                 goto bail;
590         }
591
592         /*
593          * get_more_blocks() expects us to describe a hole by clearing
594          * the mapped bit on bh_result().
595          *
596          * Consider an unwritten extent as a hole.
597          */
598         if (p_blkno && !(ext_flags & OCFS2_EXT_UNWRITTEN))
599                 map_bh(bh_result, inode->i_sb, p_blkno);
600         else {
601                 /*
602                  * ocfs2_prepare_inode_for_write() should have caught
603                  * the case where we'd be filling a hole and triggered
604                  * a buffered write instead.
605                  */
606                 if (create) {
607                         ret = -EIO;
608                         mlog_errno(ret);
609                         goto bail;
610                 }
611
612                 clear_buffer_mapped(bh_result);
613         }
614
615         /* make sure we don't map more than max_blocks blocks here as
616            that's all the kernel will handle at this point. */
617         if (max_blocks < contig_blocks)
618                 contig_blocks = max_blocks;
619         bh_result->b_size = contig_blocks << blocksize_bits;
620 bail:
621         return ret;
622 }
623
624 /* 
625  * ocfs2_dio_end_io is called by the dio core when a dio is finished.  We're
626  * particularly interested in the aio/dio case.  Like the core uses
627  * i_alloc_sem, we use the rw_lock DLM lock to protect io on one node from
628  * truncation on another.
629  */
630 static void ocfs2_dio_end_io(struct kiocb *iocb,
631                              loff_t offset,
632                              ssize_t bytes,
633                              void *private)
634 {
635         struct inode *inode = iocb->ki_filp->f_path.dentry->d_inode;
636         int level;
637
638         /* this io's submitter should not have unlocked this before we could */
639         BUG_ON(!ocfs2_iocb_is_rw_locked(iocb));
640
641         ocfs2_iocb_clear_rw_locked(iocb);
642
643         level = ocfs2_iocb_rw_locked_level(iocb);
644         if (!level)
645                 up_read(&inode->i_alloc_sem);
646         ocfs2_rw_unlock(inode, level);
647 }
648
649 /*
650  * ocfs2_invalidatepage() and ocfs2_releasepage() are shamelessly stolen
651  * from ext3.  PageChecked() bits have been removed as OCFS2 does not
652  * do journalled data.
653  */
654 static void ocfs2_invalidatepage(struct page *page, unsigned long offset)
655 {
656         journal_t *journal = OCFS2_SB(page->mapping->host->i_sb)->journal->j_journal;
657
658         jbd2_journal_invalidatepage(journal, page, offset);
659 }
660
661 static int ocfs2_releasepage(struct page *page, gfp_t wait)
662 {
663         journal_t *journal = OCFS2_SB(page->mapping->host->i_sb)->journal->j_journal;
664
665         if (!page_has_buffers(page))
666                 return 0;
667         return jbd2_journal_try_to_free_buffers(journal, page, wait);
668 }
669
670 static ssize_t ocfs2_direct_IO(int rw,
671                                struct kiocb *iocb,
672                                const struct iovec *iov,
673                                loff_t offset,
674                                unsigned long nr_segs)
675 {
676         struct file *file = iocb->ki_filp;
677         struct inode *inode = file->f_path.dentry->d_inode->i_mapping->host;
678         int ret;
679
680         mlog_entry_void();
681
682         /*
683          * Fallback to buffered I/O if we see an inode without
684          * extents.
685          */
686         if (OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL)
687                 return 0;
688
689         ret = blockdev_direct_IO_no_locking(rw, iocb, inode,
690                                             inode->i_sb->s_bdev, iov, offset,
691                                             nr_segs, 
692                                             ocfs2_direct_IO_get_blocks,
693                                             ocfs2_dio_end_io);
694
695         mlog_exit(ret);
696         return ret;
697 }
698
699 static void ocfs2_figure_cluster_boundaries(struct ocfs2_super *osb,
700                                             u32 cpos,
701                                             unsigned int *start,
702                                             unsigned int *end)
703 {
704         unsigned int cluster_start = 0, cluster_end = PAGE_CACHE_SIZE;
705
706         if (unlikely(PAGE_CACHE_SHIFT > osb->s_clustersize_bits)) {
707                 unsigned int cpp;
708
709                 cpp = 1 << (PAGE_CACHE_SHIFT - osb->s_clustersize_bits);
710
711                 cluster_start = cpos % cpp;
712                 cluster_start = cluster_start << osb->s_clustersize_bits;
713
714                 cluster_end = cluster_start + osb->s_clustersize;
715         }
716
717         BUG_ON(cluster_start > PAGE_SIZE);
718         BUG_ON(cluster_end > PAGE_SIZE);
719
720         if (start)
721                 *start = cluster_start;
722         if (end)
723                 *end = cluster_end;
724 }
725
726 /*
727  * 'from' and 'to' are the region in the page to avoid zeroing.
728  *
729  * If pagesize > clustersize, this function will avoid zeroing outside
730  * of the cluster boundary.
731  *
732  * from == to == 0 is code for "zero the entire cluster region"
733  */
734 static void ocfs2_clear_page_regions(struct page *page,
735                                      struct ocfs2_super *osb, u32 cpos,
736                                      unsigned from, unsigned to)
737 {
738         void *kaddr;
739         unsigned int cluster_start, cluster_end;
740
741         ocfs2_figure_cluster_boundaries(osb, cpos, &cluster_start, &cluster_end);
742
743         kaddr = kmap_atomic(page, KM_USER0);
744
745         if (from || to) {
746                 if (from > cluster_start)
747                         memset(kaddr + cluster_start, 0, from - cluster_start);
748                 if (to < cluster_end)
749                         memset(kaddr + to, 0, cluster_end - to);
750         } else {
751                 memset(kaddr + cluster_start, 0, cluster_end - cluster_start);
752         }
753
754         kunmap_atomic(kaddr, KM_USER0);
755 }
756
757 /*
758  * Nonsparse file systems fully allocate before we get to the write
759  * code. This prevents ocfs2_write() from tagging the write as an
760  * allocating one, which means ocfs2_map_page_blocks() might try to
761  * read-in the blocks at the tail of our file. Avoid reading them by
762  * testing i_size against each block offset.
763  */
764 static int ocfs2_should_read_blk(struct inode *inode, struct page *page,
765                                  unsigned int block_start)
766 {
767         u64 offset = page_offset(page) + block_start;
768
769         if (ocfs2_sparse_alloc(OCFS2_SB(inode->i_sb)))
770                 return 1;
771
772         if (i_size_read(inode) > offset)
773                 return 1;
774
775         return 0;
776 }
777
778 /*
779  * Some of this taken from block_prepare_write(). We already have our
780  * mapping by now though, and the entire write will be allocating or
781  * it won't, so not much need to use BH_New.
782  *
783  * This will also skip zeroing, which is handled externally.
784  */
785 int ocfs2_map_page_blocks(struct page *page, u64 *p_blkno,
786                           struct inode *inode, unsigned int from,
787                           unsigned int to, int new)
788 {
789         int ret = 0;
790         struct buffer_head *head, *bh, *wait[2], **wait_bh = wait;
791         unsigned int block_end, block_start;
792         unsigned int bsize = 1 << inode->i_blkbits;
793
794         if (!page_has_buffers(page))
795                 create_empty_buffers(page, bsize, 0);
796
797         head = page_buffers(page);
798         for (bh = head, block_start = 0; bh != head || !block_start;
799              bh = bh->b_this_page, block_start += bsize) {
800                 block_end = block_start + bsize;
801
802                 clear_buffer_new(bh);
803
804                 /*
805                  * Ignore blocks outside of our i/o range -
806                  * they may belong to unallocated clusters.
807                  */
808                 if (block_start >= to || block_end <= from) {
809                         if (PageUptodate(page))
810                                 set_buffer_uptodate(bh);
811                         continue;
812                 }
813
814                 /*
815                  * For an allocating write with cluster size >= page
816                  * size, we always write the entire page.
817                  */
818                 if (new)
819                         set_buffer_new(bh);
820
821                 if (!buffer_mapped(bh)) {
822                         map_bh(bh, inode->i_sb, *p_blkno);
823                         unmap_underlying_metadata(bh->b_bdev, bh->b_blocknr);
824                 }
825
826                 if (PageUptodate(page)) {
827                         if (!buffer_uptodate(bh))
828                                 set_buffer_uptodate(bh);
829                 } else if (!buffer_uptodate(bh) && !buffer_delay(bh) &&
830                            !buffer_new(bh) &&
831                            ocfs2_should_read_blk(inode, page, block_start) &&
832                            (block_start < from || block_end > to)) {
833                         ll_rw_block(READ, 1, &bh);
834                         *wait_bh++=bh;
835                 }
836
837                 *p_blkno = *p_blkno + 1;
838         }
839
840         /*
841          * If we issued read requests - let them complete.
842          */
843         while(wait_bh > wait) {
844                 wait_on_buffer(*--wait_bh);
845                 if (!buffer_uptodate(*wait_bh))
846                         ret = -EIO;
847         }
848
849         if (ret == 0 || !new)
850                 return ret;
851
852         /*
853          * If we get -EIO above, zero out any newly allocated blocks
854          * to avoid exposing stale data.
855          */
856         bh = head;
857         block_start = 0;
858         do {
859                 block_end = block_start + bsize;
860                 if (block_end <= from)
861                         goto next_bh;
862                 if (block_start >= to)
863                         break;
864
865                 zero_user(page, block_start, bh->b_size);
866                 set_buffer_uptodate(bh);
867                 mark_buffer_dirty(bh);
868
869 next_bh:
870                 block_start = block_end;
871                 bh = bh->b_this_page;
872         } while (bh != head);
873
874         return ret;
875 }
876
877 #if (PAGE_CACHE_SIZE >= OCFS2_MAX_CLUSTERSIZE)
878 #define OCFS2_MAX_CTXT_PAGES    1
879 #else
880 #define OCFS2_MAX_CTXT_PAGES    (OCFS2_MAX_CLUSTERSIZE / PAGE_CACHE_SIZE)
881 #endif
882
883 #define OCFS2_MAX_CLUSTERS_PER_PAGE     (PAGE_CACHE_SIZE / OCFS2_MIN_CLUSTERSIZE)
884
885 /*
886  * Describe the state of a single cluster to be written to.
887  */
888 struct ocfs2_write_cluster_desc {
889         u32             c_cpos;
890         u32             c_phys;
891         /*
892          * Give this a unique field because c_phys eventually gets
893          * filled.
894          */
895         unsigned        c_new;
896         unsigned        c_unwritten;
897 };
898
899 static inline int ocfs2_should_zero_cluster(struct ocfs2_write_cluster_desc *d)
900 {
901         return d->c_new || d->c_unwritten;
902 }
903
904 struct ocfs2_write_ctxt {
905         /* Logical cluster position / len of write */
906         u32                             w_cpos;
907         u32                             w_clen;
908
909         struct ocfs2_write_cluster_desc w_desc[OCFS2_MAX_CLUSTERS_PER_PAGE];
910
911         /*
912          * This is true if page_size > cluster_size.
913          *
914          * It triggers a set of special cases during write which might
915          * have to deal with allocating writes to partial pages.
916          */
917         unsigned int                    w_large_pages;
918
919         /*
920          * Pages involved in this write.
921          *
922          * w_target_page is the page being written to by the user.
923          *
924          * w_pages is an array of pages which always contains
925          * w_target_page, and in the case of an allocating write with
926          * page_size < cluster size, it will contain zero'd and mapped
927          * pages adjacent to w_target_page which need to be written
928          * out in so that future reads from that region will get
929          * zero's.
930          */
931         struct page                     *w_pages[OCFS2_MAX_CTXT_PAGES];
932         unsigned int                    w_num_pages;
933         struct page                     *w_target_page;
934
935         /*
936          * ocfs2_write_end() uses this to know what the real range to
937          * write in the target should be.
938          */
939         unsigned int                    w_target_from;
940         unsigned int                    w_target_to;
941
942         /*
943          * We could use journal_current_handle() but this is cleaner,
944          * IMHO -Mark
945          */
946         handle_t                        *w_handle;
947
948         struct buffer_head              *w_di_bh;
949
950         struct ocfs2_cached_dealloc_ctxt w_dealloc;
951 };
952
953 void ocfs2_unlock_and_free_pages(struct page **pages, int num_pages)
954 {
955         int i;
956
957         for(i = 0; i < num_pages; i++) {
958                 if (pages[i]) {
959                         unlock_page(pages[i]);
960                         mark_page_accessed(pages[i]);
961                         page_cache_release(pages[i]);
962                 }
963         }
964 }
965
966 static void ocfs2_free_write_ctxt(struct ocfs2_write_ctxt *wc)
967 {
968         ocfs2_unlock_and_free_pages(wc->w_pages, wc->w_num_pages);
969
970         brelse(wc->w_di_bh);
971         kfree(wc);
972 }
973
974 static int ocfs2_alloc_write_ctxt(struct ocfs2_write_ctxt **wcp,
975                                   struct ocfs2_super *osb, loff_t pos,
976                                   unsigned len, struct buffer_head *di_bh)
977 {
978         u32 cend;
979         struct ocfs2_write_ctxt *wc;
980
981         wc = kzalloc(sizeof(struct ocfs2_write_ctxt), GFP_NOFS);
982         if (!wc)
983                 return -ENOMEM;
984
985         wc->w_cpos = pos >> osb->s_clustersize_bits;
986         cend = (pos + len - 1) >> osb->s_clustersize_bits;
987         wc->w_clen = cend - wc->w_cpos + 1;
988         get_bh(di_bh);
989         wc->w_di_bh = di_bh;
990
991         if (unlikely(PAGE_CACHE_SHIFT > osb->s_clustersize_bits))
992                 wc->w_large_pages = 1;
993         else
994                 wc->w_large_pages = 0;
995
996         ocfs2_init_dealloc_ctxt(&wc->w_dealloc);
997
998         *wcp = wc;
999
1000         return 0;
1001 }
1002
1003 /*
1004  * If a page has any new buffers, zero them out here, and mark them uptodate
1005  * and dirty so they'll be written out (in order to prevent uninitialised
1006  * block data from leaking). And clear the new bit.
1007  */
1008 static void ocfs2_zero_new_buffers(struct page *page, unsigned from, unsigned to)
1009 {
1010         unsigned int block_start, block_end;
1011         struct buffer_head *head, *bh;
1012
1013         BUG_ON(!PageLocked(page));
1014         if (!page_has_buffers(page))
1015                 return;
1016
1017         bh = head = page_buffers(page);
1018         block_start = 0;
1019         do {
1020                 block_end = block_start + bh->b_size;
1021
1022                 if (buffer_new(bh)) {
1023                         if (block_end > from && block_start < to) {
1024                                 if (!PageUptodate(page)) {
1025                                         unsigned start, end;
1026
1027                                         start = max(from, block_start);
1028                                         end = min(to, block_end);
1029
1030                                         zero_user_segment(page, start, end);
1031                                         set_buffer_uptodate(bh);
1032                                 }
1033
1034                                 clear_buffer_new(bh);
1035                                 mark_buffer_dirty(bh);
1036                         }
1037                 }
1038
1039                 block_start = block_end;
1040                 bh = bh->b_this_page;
1041         } while (bh != head);
1042 }
1043
1044 /*
1045  * Only called when we have a failure during allocating write to write
1046  * zero's to the newly allocated region.
1047  */
1048 static void ocfs2_write_failure(struct inode *inode,
1049                                 struct ocfs2_write_ctxt *wc,
1050                                 loff_t user_pos, unsigned user_len)
1051 {
1052         int i;
1053         unsigned from = user_pos & (PAGE_CACHE_SIZE - 1),
1054                 to = user_pos + user_len;
1055         struct page *tmppage;
1056
1057         ocfs2_zero_new_buffers(wc->w_target_page, from, to);
1058
1059         for(i = 0; i < wc->w_num_pages; i++) {
1060                 tmppage = wc->w_pages[i];
1061
1062                 if (page_has_buffers(tmppage)) {
1063                         if (ocfs2_should_order_data(inode))
1064                                 ocfs2_jbd2_file_inode(wc->w_handle, inode);
1065
1066                         block_commit_write(tmppage, from, to);
1067                 }
1068         }
1069 }
1070
1071 static int ocfs2_prepare_page_for_write(struct inode *inode, u64 *p_blkno,
1072                                         struct ocfs2_write_ctxt *wc,
1073                                         struct page *page, u32 cpos,
1074                                         loff_t user_pos, unsigned user_len,
1075                                         int new)
1076 {
1077         int ret;
1078         unsigned int map_from = 0, map_to = 0;
1079         unsigned int cluster_start, cluster_end;
1080         unsigned int user_data_from = 0, user_data_to = 0;
1081
1082         ocfs2_figure_cluster_boundaries(OCFS2_SB(inode->i_sb), cpos,
1083                                         &cluster_start, &cluster_end);
1084
1085         if (page == wc->w_target_page) {
1086                 map_from = user_pos & (PAGE_CACHE_SIZE - 1);
1087                 map_to = map_from + user_len;
1088
1089                 if (new)
1090                         ret = ocfs2_map_page_blocks(page, p_blkno, inode,
1091                                                     cluster_start, cluster_end,
1092                                                     new);
1093                 else
1094                         ret = ocfs2_map_page_blocks(page, p_blkno, inode,
1095                                                     map_from, map_to, new);
1096                 if (ret) {
1097                         mlog_errno(ret);
1098                         goto out;
1099                 }
1100
1101                 user_data_from = map_from;
1102                 user_data_to = map_to;
1103                 if (new) {
1104                         map_from = cluster_start;
1105                         map_to = cluster_end;
1106                 }
1107         } else {
1108                 /*
1109                  * If we haven't allocated the new page yet, we
1110                  * shouldn't be writing it out without copying user
1111                  * data. This is likely a math error from the caller.
1112                  */
1113                 BUG_ON(!new);
1114
1115                 map_from = cluster_start;
1116                 map_to = cluster_end;
1117
1118                 ret = ocfs2_map_page_blocks(page, p_blkno, inode,
1119                                             cluster_start, cluster_end, new);
1120                 if (ret) {
1121                         mlog_errno(ret);
1122                         goto out;
1123                 }
1124         }
1125
1126         /*
1127          * Parts of newly allocated pages need to be zero'd.
1128          *
1129          * Above, we have also rewritten 'to' and 'from' - as far as
1130          * the rest of the function is concerned, the entire cluster
1131          * range inside of a page needs to be written.
1132          *
1133          * We can skip this if the page is up to date - it's already
1134          * been zero'd from being read in as a hole.
1135          */
1136         if (new && !PageUptodate(page))
1137                 ocfs2_clear_page_regions(page, OCFS2_SB(inode->i_sb),
1138                                          cpos, user_data_from, user_data_to);
1139
1140         flush_dcache_page(page);
1141
1142 out:
1143         return ret;
1144 }
1145
1146 /*
1147  * This function will only grab one clusters worth of pages.
1148  */
1149 static int ocfs2_grab_pages_for_write(struct address_space *mapping,
1150                                       struct ocfs2_write_ctxt *wc,
1151                                       u32 cpos, loff_t user_pos, int new,
1152                                       struct page *mmap_page)
1153 {
1154         int ret = 0, i;
1155         unsigned long start, target_index, index;
1156         struct inode *inode = mapping->host;
1157
1158         target_index = user_pos >> PAGE_CACHE_SHIFT;
1159
1160         /*
1161          * Figure out how many pages we'll be manipulating here. For
1162          * non allocating write, we just change the one
1163          * page. Otherwise, we'll need a whole clusters worth.
1164          */
1165         if (new) {
1166                 wc->w_num_pages = ocfs2_pages_per_cluster(inode->i_sb);
1167                 start = ocfs2_align_clusters_to_page_index(inode->i_sb, cpos);
1168         } else {
1169                 wc->w_num_pages = 1;
1170                 start = target_index;
1171         }
1172
1173         for(i = 0; i < wc->w_num_pages; i++) {
1174                 index = start + i;
1175
1176                 if (index == target_index && mmap_page) {
1177                         /*
1178                          * ocfs2_pagemkwrite() is a little different
1179                          * and wants us to directly use the page
1180                          * passed in.
1181                          */
1182                         lock_page(mmap_page);
1183
1184                         if (mmap_page->mapping != mapping) {
1185                                 unlock_page(mmap_page);
1186                                 /*
1187                                  * Sanity check - the locking in
1188                                  * ocfs2_pagemkwrite() should ensure
1189                                  * that this code doesn't trigger.
1190                                  */
1191                                 ret = -EINVAL;
1192                                 mlog_errno(ret);
1193                                 goto out;
1194                         }
1195
1196                         page_cache_get(mmap_page);
1197                         wc->w_pages[i] = mmap_page;
1198                 } else {
1199                         wc->w_pages[i] = find_or_create_page(mapping, index,
1200                                                              GFP_NOFS);
1201                         if (!wc->w_pages[i]) {
1202                                 ret = -ENOMEM;
1203                                 mlog_errno(ret);
1204                                 goto out;
1205                         }
1206                 }
1207
1208                 if (index == target_index)
1209                         wc->w_target_page = wc->w_pages[i];
1210         }
1211 out:
1212         return ret;
1213 }
1214
1215 /*
1216  * Prepare a single cluster for write one cluster into the file.
1217  */
1218 static int ocfs2_write_cluster(struct address_space *mapping,
1219                                u32 phys, unsigned int unwritten,
1220                                struct ocfs2_alloc_context *data_ac,
1221                                struct ocfs2_alloc_context *meta_ac,
1222                                struct ocfs2_write_ctxt *wc, u32 cpos,
1223                                loff_t user_pos, unsigned user_len)
1224 {
1225         int ret, i, new, should_zero = 0;
1226         u64 v_blkno, p_blkno;
1227         struct inode *inode = mapping->host;
1228         struct ocfs2_extent_tree et;
1229
1230         new = phys == 0 ? 1 : 0;
1231         if (new || unwritten)
1232                 should_zero = 1;
1233
1234         if (new) {
1235                 u32 tmp_pos;
1236
1237                 /*
1238                  * This is safe to call with the page locks - it won't take
1239                  * any additional semaphores or cluster locks.
1240                  */
1241                 tmp_pos = cpos;
1242                 ret = ocfs2_add_inode_data(OCFS2_SB(inode->i_sb), inode,
1243                                            &tmp_pos, 1, 0, wc->w_di_bh,
1244                                            wc->w_handle, data_ac,
1245                                            meta_ac, NULL);
1246                 /*
1247                  * This shouldn't happen because we must have already
1248                  * calculated the correct meta data allocation required. The
1249                  * internal tree allocation code should know how to increase
1250                  * transaction credits itself.
1251                  *
1252                  * If need be, we could handle -EAGAIN for a
1253                  * RESTART_TRANS here.
1254                  */
1255                 mlog_bug_on_msg(ret == -EAGAIN,
1256                                 "Inode %llu: EAGAIN return during allocation.\n",
1257                                 (unsigned long long)OCFS2_I(inode)->ip_blkno);
1258                 if (ret < 0) {
1259                         mlog_errno(ret);
1260                         goto out;
1261                 }
1262         } else if (unwritten) {
1263                 ocfs2_init_dinode_extent_tree(&et, inode, wc->w_di_bh);
1264                 ret = ocfs2_mark_extent_written(inode, &et,
1265                                                 wc->w_handle, cpos, 1, phys,
1266                                                 meta_ac, &wc->w_dealloc);
1267                 if (ret < 0) {
1268                         mlog_errno(ret);
1269                         goto out;
1270                 }
1271         }
1272
1273         if (should_zero)
1274                 v_blkno = ocfs2_clusters_to_blocks(inode->i_sb, cpos);
1275         else
1276                 v_blkno = user_pos >> inode->i_sb->s_blocksize_bits;
1277
1278         /*
1279          * The only reason this should fail is due to an inability to
1280          * find the extent added.
1281          */
1282         ret = ocfs2_extent_map_get_blocks(inode, v_blkno, &p_blkno, NULL,
1283                                           NULL);
1284         if (ret < 0) {
1285                 ocfs2_error(inode->i_sb, "Corrupting extend for inode %llu, "
1286                             "at logical block %llu",
1287                             (unsigned long long)OCFS2_I(inode)->ip_blkno,
1288                             (unsigned long long)v_blkno);
1289                 goto out;
1290         }
1291
1292         BUG_ON(p_blkno == 0);
1293
1294         for(i = 0; i < wc->w_num_pages; i++) {
1295                 int tmpret;
1296
1297                 tmpret = ocfs2_prepare_page_for_write(inode, &p_blkno, wc,
1298                                                       wc->w_pages[i], cpos,
1299                                                       user_pos, user_len,
1300                                                       should_zero);
1301                 if (tmpret) {
1302                         mlog_errno(tmpret);
1303                         if (ret == 0)
1304                                 tmpret = ret;
1305                 }
1306         }
1307
1308         /*
1309          * We only have cleanup to do in case of allocating write.
1310          */
1311         if (ret && new)
1312                 ocfs2_write_failure(inode, wc, user_pos, user_len);
1313
1314 out:
1315
1316         return ret;
1317 }
1318
1319 static int ocfs2_write_cluster_by_desc(struct address_space *mapping,
1320                                        struct ocfs2_alloc_context *data_ac,
1321                                        struct ocfs2_alloc_context *meta_ac,
1322                                        struct ocfs2_write_ctxt *wc,
1323                                        loff_t pos, unsigned len)
1324 {
1325         int ret, i;
1326         loff_t cluster_off;
1327         unsigned int local_len = len;
1328         struct ocfs2_write_cluster_desc *desc;
1329         struct ocfs2_super *osb = OCFS2_SB(mapping->host->i_sb);
1330
1331         for (i = 0; i < wc->w_clen; i++) {
1332                 desc = &wc->w_desc[i];
1333
1334                 /*
1335                  * We have to make sure that the total write passed in
1336                  * doesn't extend past a single cluster.
1337                  */
1338                 local_len = len;
1339                 cluster_off = pos & (osb->s_clustersize - 1);
1340                 if ((cluster_off + local_len) > osb->s_clustersize)
1341                         local_len = osb->s_clustersize - cluster_off;
1342
1343                 ret = ocfs2_write_cluster(mapping, desc->c_phys,
1344                                           desc->c_unwritten, data_ac, meta_ac,
1345                                           wc, desc->c_cpos, pos, local_len);
1346                 if (ret) {
1347                         mlog_errno(ret);
1348                         goto out;
1349                 }
1350
1351                 len -= local_len;
1352                 pos += local_len;
1353         }
1354
1355         ret = 0;
1356 out:
1357         return ret;
1358 }
1359
1360 /*
1361  * ocfs2_write_end() wants to know which parts of the target page it
1362  * should complete the write on. It's easiest to compute them ahead of
1363  * time when a more complete view of the write is available.
1364  */
1365 static void ocfs2_set_target_boundaries(struct ocfs2_super *osb,
1366                                         struct ocfs2_write_ctxt *wc,
1367                                         loff_t pos, unsigned len, int alloc)
1368 {
1369         struct ocfs2_write_cluster_desc *desc;
1370
1371         wc->w_target_from = pos & (PAGE_CACHE_SIZE - 1);
1372         wc->w_target_to = wc->w_target_from + len;
1373
1374         if (alloc == 0)
1375                 return;
1376
1377         /*
1378          * Allocating write - we may have different boundaries based
1379          * on page size and cluster size.
1380          *
1381          * NOTE: We can no longer compute one value from the other as
1382          * the actual write length and user provided length may be
1383          * different.
1384          */
1385
1386         if (wc->w_large_pages) {
1387                 /*
1388                  * We only care about the 1st and last cluster within
1389                  * our range and whether they should be zero'd or not. Either
1390                  * value may be extended out to the start/end of a
1391                  * newly allocated cluster.
1392                  */
1393                 desc = &wc->w_desc[0];
1394                 if (ocfs2_should_zero_cluster(desc))
1395                         ocfs2_figure_cluster_boundaries(osb,
1396                                                         desc->c_cpos,
1397                                                         &wc->w_target_from,
1398                                                         NULL);
1399
1400                 desc = &wc->w_desc[wc->w_clen - 1];
1401                 if (ocfs2_should_zero_cluster(desc))
1402                         ocfs2_figure_cluster_boundaries(osb,
1403                                                         desc->c_cpos,
1404                                                         NULL,
1405                                                         &wc->w_target_to);
1406         } else {
1407                 wc->w_target_from = 0;
1408                 wc->w_target_to = PAGE_CACHE_SIZE;
1409         }
1410 }
1411
1412 /*
1413  * Populate each single-cluster write descriptor in the write context
1414  * with information about the i/o to be done.
1415  *
1416  * Returns the number of clusters that will have to be allocated, as
1417  * well as a worst case estimate of the number of extent records that
1418  * would have to be created during a write to an unwritten region.
1419  */
1420 static int ocfs2_populate_write_desc(struct inode *inode,
1421                                      struct ocfs2_write_ctxt *wc,
1422                                      unsigned int *clusters_to_alloc,
1423                                      unsigned int *extents_to_split)
1424 {
1425         int ret;
1426         struct ocfs2_write_cluster_desc *desc;
1427         unsigned int num_clusters = 0;
1428         unsigned int ext_flags = 0;
1429         u32 phys = 0;
1430         int i;
1431
1432         *clusters_to_alloc = 0;
1433         *extents_to_split = 0;
1434
1435         for (i = 0; i < wc->w_clen; i++) {
1436                 desc = &wc->w_desc[i];
1437                 desc->c_cpos = wc->w_cpos + i;
1438
1439                 if (num_clusters == 0) {
1440                         /*
1441                          * Need to look up the next extent record.
1442                          */
1443                         ret = ocfs2_get_clusters(inode, desc->c_cpos, &phys,
1444                                                  &num_clusters, &ext_flags);
1445                         if (ret) {
1446                                 mlog_errno(ret);
1447                                 goto out;
1448                         }
1449
1450                         /*
1451                          * Assume worst case - that we're writing in
1452                          * the middle of the extent.
1453                          *
1454                          * We can assume that the write proceeds from
1455                          * left to right, in which case the extent
1456                          * insert code is smart enough to coalesce the
1457                          * next splits into the previous records created.
1458                          */
1459                         if (ext_flags & OCFS2_EXT_UNWRITTEN)
1460                                 *extents_to_split = *extents_to_split + 2;
1461                 } else if (phys) {
1462                         /*
1463                          * Only increment phys if it doesn't describe
1464                          * a hole.
1465                          */
1466                         phys++;
1467                 }
1468
1469                 desc->c_phys = phys;
1470                 if (phys == 0) {
1471                         desc->c_new = 1;
1472                         *clusters_to_alloc = *clusters_to_alloc + 1;
1473                 }
1474                 if (ext_flags & OCFS2_EXT_UNWRITTEN)
1475                         desc->c_unwritten = 1;
1476
1477                 num_clusters--;
1478         }
1479
1480         ret = 0;
1481 out:
1482         return ret;
1483 }
1484
1485 static int ocfs2_write_begin_inline(struct address_space *mapping,
1486                                     struct inode *inode,
1487                                     struct ocfs2_write_ctxt *wc)
1488 {
1489         int ret;
1490         struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
1491         struct page *page;
1492         handle_t *handle;
1493         struct ocfs2_dinode *di = (struct ocfs2_dinode *)wc->w_di_bh->b_data;
1494
1495         page = find_or_create_page(mapping, 0, GFP_NOFS);
1496         if (!page) {
1497                 ret = -ENOMEM;
1498                 mlog_errno(ret);
1499                 goto out;
1500         }
1501         /*
1502          * If we don't set w_num_pages then this page won't get unlocked
1503          * and freed on cleanup of the write context.
1504          */
1505         wc->w_pages[0] = wc->w_target_page = page;
1506         wc->w_num_pages = 1;
1507
1508         handle = ocfs2_start_trans(osb, OCFS2_INODE_UPDATE_CREDITS);
1509         if (IS_ERR(handle)) {
1510                 ret = PTR_ERR(handle);
1511                 mlog_errno(ret);
1512                 goto out;
1513         }
1514
1515         ret = ocfs2_journal_access_di(handle, inode, wc->w_di_bh,
1516                                       OCFS2_JOURNAL_ACCESS_WRITE);
1517         if (ret) {
1518                 ocfs2_commit_trans(osb, handle);
1519
1520                 mlog_errno(ret);
1521                 goto out;
1522         }
1523
1524         if (!(OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL))
1525                 ocfs2_set_inode_data_inline(inode, di);
1526
1527         if (!PageUptodate(page)) {
1528                 ret = ocfs2_read_inline_data(inode, page, wc->w_di_bh);
1529                 if (ret) {
1530                         ocfs2_commit_trans(osb, handle);
1531
1532                         goto out;
1533                 }
1534         }
1535
1536         wc->w_handle = handle;
1537 out:
1538         return ret;
1539 }
1540
1541 int ocfs2_size_fits_inline_data(struct buffer_head *di_bh, u64 new_size)
1542 {
1543         struct ocfs2_dinode *di = (struct ocfs2_dinode *)di_bh->b_data;
1544
1545         if (new_size <= le16_to_cpu(di->id2.i_data.id_count))
1546                 return 1;
1547         return 0;
1548 }
1549
1550 static int ocfs2_try_to_write_inline_data(struct address_space *mapping,
1551                                           struct inode *inode, loff_t pos,
1552                                           unsigned len, struct page *mmap_page,
1553                                           struct ocfs2_write_ctxt *wc)
1554 {
1555         int ret, written = 0;
1556         loff_t end = pos + len;
1557         struct ocfs2_inode_info *oi = OCFS2_I(inode);
1558
1559         mlog(0, "Inode %llu, write of %u bytes at off %llu. features: 0x%x\n",
1560              (unsigned long long)oi->ip_blkno, len, (unsigned long long)pos,
1561              oi->ip_dyn_features);
1562
1563         /*
1564          * Handle inodes which already have inline data 1st.
1565          */
1566         if (oi->ip_dyn_features & OCFS2_INLINE_DATA_FL) {
1567                 if (mmap_page == NULL &&
1568                     ocfs2_size_fits_inline_data(wc->w_di_bh, end))
1569                         goto do_inline_write;
1570
1571                 /*
1572                  * The write won't fit - we have to give this inode an
1573                  * inline extent list now.
1574                  */
1575                 ret = ocfs2_convert_inline_data_to_extents(inode, wc->w_di_bh);
1576                 if (ret)
1577                         mlog_errno(ret);
1578                 goto out;
1579         }
1580
1581         /*
1582          * Check whether the inode can accept inline data.
1583          */
1584         if (oi->ip_clusters != 0 || i_size_read(inode) != 0)
1585                 return 0;
1586
1587         /*
1588          * Check whether the write can fit.
1589          */
1590         if (mmap_page || end > ocfs2_max_inline_data(inode->i_sb))
1591                 return 0;
1592
1593 do_inline_write:
1594         ret = ocfs2_write_begin_inline(mapping, inode, wc);
1595         if (ret) {
1596                 mlog_errno(ret);
1597                 goto out;
1598         }
1599
1600         /*
1601          * This signals to the caller that the data can be written
1602          * inline.
1603          */
1604         written = 1;
1605 out:
1606         return written ? written : ret;
1607 }
1608
1609 /*
1610  * This function only does anything for file systems which can't
1611  * handle sparse files.
1612  *
1613  * What we want to do here is fill in any hole between the current end
1614  * of allocation and the end of our write. That way the rest of the
1615  * write path can treat it as an non-allocating write, which has no
1616  * special case code for sparse/nonsparse files.
1617  */
1618 static int ocfs2_expand_nonsparse_inode(struct inode *inode, loff_t pos,
1619                                         unsigned len,
1620                                         struct ocfs2_write_ctxt *wc)
1621 {
1622         int ret;
1623         struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
1624         loff_t newsize = pos + len;
1625
1626         if (ocfs2_sparse_alloc(osb))
1627                 return 0;
1628
1629         if (newsize <= i_size_read(inode))
1630                 return 0;
1631
1632         ret = ocfs2_extend_no_holes(inode, newsize, newsize - len);
1633         if (ret)
1634                 mlog_errno(ret);
1635
1636         return ret;
1637 }
1638
1639 int ocfs2_write_begin_nolock(struct address_space *mapping,
1640                              loff_t pos, unsigned len, unsigned flags,
1641                              struct page **pagep, void **fsdata,
1642                              struct buffer_head *di_bh, struct page *mmap_page)
1643 {
1644         int ret, credits = OCFS2_INODE_UPDATE_CREDITS;
1645         unsigned int clusters_to_alloc, extents_to_split;
1646         struct ocfs2_write_ctxt *wc;
1647         struct inode *inode = mapping->host;
1648         struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
1649         struct ocfs2_dinode *di;
1650         struct ocfs2_alloc_context *data_ac = NULL;
1651         struct ocfs2_alloc_context *meta_ac = NULL;
1652         handle_t *handle;
1653         struct ocfs2_extent_tree et;
1654
1655         ret = ocfs2_alloc_write_ctxt(&wc, osb, pos, len, di_bh);
1656         if (ret) {
1657                 mlog_errno(ret);
1658                 return ret;
1659         }
1660
1661         if (ocfs2_supports_inline_data(osb)) {
1662                 ret = ocfs2_try_to_write_inline_data(mapping, inode, pos, len,
1663                                                      mmap_page, wc);
1664                 if (ret == 1) {
1665                         ret = 0;
1666                         goto success;
1667                 }
1668                 if (ret < 0) {
1669                         mlog_errno(ret);
1670                         goto out;
1671                 }
1672         }
1673
1674         ret = ocfs2_expand_nonsparse_inode(inode, pos, len, wc);
1675         if (ret) {
1676                 mlog_errno(ret);
1677                 goto out;
1678         }
1679
1680         ret = ocfs2_populate_write_desc(inode, wc, &clusters_to_alloc,
1681                                         &extents_to_split);
1682         if (ret) {
1683                 mlog_errno(ret);
1684                 goto out;
1685         }
1686
1687         di = (struct ocfs2_dinode *)wc->w_di_bh->b_data;
1688
1689         /*
1690          * We set w_target_from, w_target_to here so that
1691          * ocfs2_write_end() knows which range in the target page to
1692          * write out. An allocation requires that we write the entire
1693          * cluster range.
1694          */
1695         if (clusters_to_alloc || extents_to_split) {
1696                 /*
1697                  * XXX: We are stretching the limits of
1698                  * ocfs2_lock_allocators(). It greatly over-estimates
1699                  * the work to be done.
1700                  */
1701                 mlog(0, "extend inode %llu, i_size = %lld, di->i_clusters = %u,"
1702                      " clusters_to_add = %u, extents_to_split = %u\n",
1703                      (unsigned long long)OCFS2_I(inode)->ip_blkno,
1704                      (long long)i_size_read(inode), le32_to_cpu(di->i_clusters),
1705                      clusters_to_alloc, extents_to_split);
1706
1707                 ocfs2_init_dinode_extent_tree(&et, inode, wc->w_di_bh);
1708                 ret = ocfs2_lock_allocators(inode, &et,
1709                                             clusters_to_alloc, extents_to_split,
1710                                             &data_ac, &meta_ac);
1711                 if (ret) {
1712                         mlog_errno(ret);
1713                         goto out;
1714                 }
1715
1716                 credits = ocfs2_calc_extend_credits(inode->i_sb,
1717                                                     &di->id2.i_list,
1718                                                     clusters_to_alloc);
1719
1720         }
1721
1722         ocfs2_set_target_boundaries(osb, wc, pos, len,
1723                                     clusters_to_alloc + extents_to_split);
1724
1725         handle = ocfs2_start_trans(osb, credits);
1726         if (IS_ERR(handle)) {
1727                 ret = PTR_ERR(handle);
1728                 mlog_errno(ret);
1729                 goto out;
1730         }
1731
1732         wc->w_handle = handle;
1733
1734         if (clusters_to_alloc && vfs_dq_alloc_space_nodirty(inode,
1735                         ocfs2_clusters_to_bytes(osb->sb, clusters_to_alloc))) {
1736                 ret = -EDQUOT;
1737                 goto out_commit;
1738         }
1739         /*
1740          * We don't want this to fail in ocfs2_write_end(), so do it
1741          * here.
1742          */
1743         ret = ocfs2_journal_access_di(handle, inode, wc->w_di_bh,
1744                                       OCFS2_JOURNAL_ACCESS_WRITE);
1745         if (ret) {
1746                 mlog_errno(ret);
1747                 goto out_quota;
1748         }
1749
1750         /*
1751          * Fill our page array first. That way we've grabbed enough so
1752          * that we can zero and flush if we error after adding the
1753          * extent.
1754          */
1755         ret = ocfs2_grab_pages_for_write(mapping, wc, wc->w_cpos, pos,
1756                                          clusters_to_alloc + extents_to_split,
1757                                          mmap_page);
1758         if (ret) {
1759                 mlog_errno(ret);
1760                 goto out_quota;
1761         }
1762
1763         ret = ocfs2_write_cluster_by_desc(mapping, data_ac, meta_ac, wc, pos,
1764                                           len);
1765         if (ret) {
1766                 mlog_errno(ret);
1767                 goto out_quota;
1768         }
1769
1770         if (data_ac)
1771                 ocfs2_free_alloc_context(data_ac);
1772         if (meta_ac)
1773                 ocfs2_free_alloc_context(meta_ac);
1774
1775 success:
1776         *pagep = wc->w_target_page;
1777         *fsdata = wc;
1778         return 0;
1779 out_quota:
1780         if (clusters_to_alloc)
1781                 vfs_dq_free_space(inode,
1782                           ocfs2_clusters_to_bytes(osb->sb, clusters_to_alloc));
1783 out_commit:
1784         ocfs2_commit_trans(osb, handle);
1785
1786 out:
1787         ocfs2_free_write_ctxt(wc);
1788
1789         if (data_ac)
1790                 ocfs2_free_alloc_context(data_ac);
1791         if (meta_ac)
1792                 ocfs2_free_alloc_context(meta_ac);
1793         return ret;
1794 }
1795
1796 static int ocfs2_write_begin(struct file *file, struct address_space *mapping,
1797                              loff_t pos, unsigned len, unsigned flags,
1798                              struct page **pagep, void **fsdata)
1799 {
1800         int ret;
1801         struct buffer_head *di_bh = NULL;
1802         struct inode *inode = mapping->host;
1803
1804         ret = ocfs2_inode_lock(inode, &di_bh, 1);
1805         if (ret) {
1806                 mlog_errno(ret);
1807                 return ret;
1808         }
1809
1810         /*
1811          * Take alloc sem here to prevent concurrent lookups. That way
1812          * the mapping, zeroing and tree manipulation within
1813          * ocfs2_write() will be safe against ->readpage(). This
1814          * should also serve to lock out allocation from a shared
1815          * writeable region.
1816          */
1817         down_write(&OCFS2_I(inode)->ip_alloc_sem);
1818
1819         ret = ocfs2_write_begin_nolock(mapping, pos, len, flags, pagep,
1820                                        fsdata, di_bh, NULL);
1821         if (ret) {
1822                 mlog_errno(ret);
1823                 goto out_fail;
1824         }
1825
1826         brelse(di_bh);
1827
1828         return 0;
1829
1830 out_fail:
1831         up_write(&OCFS2_I(inode)->ip_alloc_sem);
1832
1833         brelse(di_bh);
1834         ocfs2_inode_unlock(inode, 1);
1835
1836         return ret;
1837 }
1838
1839 static void ocfs2_write_end_inline(struct inode *inode, loff_t pos,
1840                                    unsigned len, unsigned *copied,
1841                                    struct ocfs2_dinode *di,
1842                                    struct ocfs2_write_ctxt *wc)
1843 {
1844         void *kaddr;
1845
1846         if (unlikely(*copied < len)) {
1847                 if (!PageUptodate(wc->w_target_page)) {
1848                         *copied = 0;
1849                         return;
1850                 }
1851         }
1852
1853         kaddr = kmap_atomic(wc->w_target_page, KM_USER0);
1854         memcpy(di->id2.i_data.id_data + pos, kaddr + pos, *copied);
1855         kunmap_atomic(kaddr, KM_USER0);
1856
1857         mlog(0, "Data written to inode at offset %llu. "
1858              "id_count = %u, copied = %u, i_dyn_features = 0x%x\n",
1859              (unsigned long long)pos, *copied,
1860              le16_to_cpu(di->id2.i_data.id_count),
1861              le16_to_cpu(di->i_dyn_features));
1862 }
1863
1864 int ocfs2_write_end_nolock(struct address_space *mapping,
1865                            loff_t pos, unsigned len, unsigned copied,
1866                            struct page *page, void *fsdata)
1867 {
1868         int i;
1869         unsigned from, to, start = pos & (PAGE_CACHE_SIZE - 1);
1870         struct inode *inode = mapping->host;
1871         struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
1872         struct ocfs2_write_ctxt *wc = fsdata;
1873         struct ocfs2_dinode *di = (struct ocfs2_dinode *)wc->w_di_bh->b_data;
1874         handle_t *handle = wc->w_handle;
1875         struct page *tmppage;
1876
1877         if (OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL) {
1878                 ocfs2_write_end_inline(inode, pos, len, &copied, di, wc);
1879                 goto out_write_size;
1880         }
1881
1882         if (unlikely(copied < len)) {
1883                 if (!PageUptodate(wc->w_target_page))
1884                         copied = 0;
1885
1886                 ocfs2_zero_new_buffers(wc->w_target_page, start+copied,
1887                                        start+len);
1888         }
1889         flush_dcache_page(wc->w_target_page);
1890
1891         for(i = 0; i < wc->w_num_pages; i++) {
1892                 tmppage = wc->w_pages[i];
1893
1894                 if (tmppage == wc->w_target_page) {
1895                         from = wc->w_target_from;
1896                         to = wc->w_target_to;
1897
1898                         BUG_ON(from > PAGE_CACHE_SIZE ||
1899                                to > PAGE_CACHE_SIZE ||
1900                                to < from);
1901                 } else {
1902                         /*
1903                          * Pages adjacent to the target (if any) imply
1904                          * a hole-filling write in which case we want
1905                          * to flush their entire range.
1906                          */
1907                         from = 0;
1908                         to = PAGE_CACHE_SIZE;
1909                 }
1910
1911                 if (page_has_buffers(tmppage)) {
1912                         if (ocfs2_should_order_data(inode))
1913                                 ocfs2_jbd2_file_inode(wc->w_handle, inode);
1914                         block_commit_write(tmppage, from, to);
1915                 }
1916         }
1917
1918 out_write_size:
1919         pos += copied;
1920         if (pos > inode->i_size) {
1921                 i_size_write(inode, pos);
1922                 mark_inode_dirty(inode);
1923         }
1924         inode->i_blocks = ocfs2_inode_sector_count(inode);
1925         di->i_size = cpu_to_le64((u64)i_size_read(inode));
1926         inode->i_mtime = inode->i_ctime = CURRENT_TIME;
1927         di->i_mtime = di->i_ctime = cpu_to_le64(inode->i_mtime.tv_sec);
1928         di->i_mtime_nsec = di->i_ctime_nsec = cpu_to_le32(inode->i_mtime.tv_nsec);
1929         ocfs2_journal_dirty(handle, wc->w_di_bh);
1930
1931         ocfs2_commit_trans(osb, handle);
1932
1933         ocfs2_run_deallocs(osb, &wc->w_dealloc);
1934
1935         ocfs2_free_write_ctxt(wc);
1936
1937         return copied;
1938 }
1939
1940 static int ocfs2_write_end(struct file *file, struct address_space *mapping,
1941                            loff_t pos, unsigned len, unsigned copied,
1942                            struct page *page, void *fsdata)
1943 {
1944         int ret;
1945         struct inode *inode = mapping->host;
1946
1947         ret = ocfs2_write_end_nolock(mapping, pos, len, copied, page, fsdata);
1948
1949         up_write(&OCFS2_I(inode)->ip_alloc_sem);
1950         ocfs2_inode_unlock(inode, 1);
1951
1952         return ret;
1953 }
1954
1955 const struct address_space_operations ocfs2_aops = {
1956         .readpage       = ocfs2_readpage,
1957         .readpages      = ocfs2_readpages,
1958         .writepage      = ocfs2_writepage,
1959         .write_begin    = ocfs2_write_begin,
1960         .write_end      = ocfs2_write_end,
1961         .bmap           = ocfs2_bmap,
1962         .sync_page      = block_sync_page,
1963         .direct_IO      = ocfs2_direct_IO,
1964         .invalidatepage = ocfs2_invalidatepage,
1965         .releasepage    = ocfs2_releasepage,
1966         .migratepage    = buffer_migrate_page,
1967 };