xref: /openbmc/linux/fs/ocfs2/aops.c (revision b34e08d5)
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 #include <cluster/masklog.h>
33 
34 #include "ocfs2.h"
35 
36 #include "alloc.h"
37 #include "aops.h"
38 #include "dlmglue.h"
39 #include "extent_map.h"
40 #include "file.h"
41 #include "inode.h"
42 #include "journal.h"
43 #include "suballoc.h"
44 #include "super.h"
45 #include "symlink.h"
46 #include "refcounttree.h"
47 #include "ocfs2_trace.h"
48 
49 #include "buffer_head_io.h"
50 
51 static int ocfs2_symlink_get_block(struct inode *inode, sector_t iblock,
52 				   struct buffer_head *bh_result, int create)
53 {
54 	int err = -EIO;
55 	int status;
56 	struct ocfs2_dinode *fe = NULL;
57 	struct buffer_head *bh = NULL;
58 	struct buffer_head *buffer_cache_bh = NULL;
59 	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
60 	void *kaddr;
61 
62 	trace_ocfs2_symlink_get_block(
63 			(unsigned long long)OCFS2_I(inode)->ip_blkno,
64 			(unsigned long long)iblock, bh_result, create);
65 
66 	BUG_ON(ocfs2_inode_is_fast_symlink(inode));
67 
68 	if ((iblock << inode->i_sb->s_blocksize_bits) > PATH_MAX + 1) {
69 		mlog(ML_ERROR, "block offset > PATH_MAX: %llu",
70 		     (unsigned long long)iblock);
71 		goto bail;
72 	}
73 
74 	status = ocfs2_read_inode_block(inode, &bh);
75 	if (status < 0) {
76 		mlog_errno(status);
77 		goto bail;
78 	}
79 	fe = (struct ocfs2_dinode *) bh->b_data;
80 
81 	if ((u64)iblock >= ocfs2_clusters_to_blocks(inode->i_sb,
82 						    le32_to_cpu(fe->i_clusters))) {
83 		err = -ENOMEM;
84 		mlog(ML_ERROR, "block offset is outside the allocated size: "
85 		     "%llu\n", (unsigned long long)iblock);
86 		goto bail;
87 	}
88 
89 	/* We don't use the page cache to create symlink data, so if
90 	 * need be, copy it over from the buffer cache. */
91 	if (!buffer_uptodate(bh_result) && ocfs2_inode_is_new(inode)) {
92 		u64 blkno = le64_to_cpu(fe->id2.i_list.l_recs[0].e_blkno) +
93 			    iblock;
94 		buffer_cache_bh = sb_getblk(osb->sb, blkno);
95 		if (!buffer_cache_bh) {
96 			err = -ENOMEM;
97 			mlog(ML_ERROR, "couldn't getblock for symlink!\n");
98 			goto bail;
99 		}
100 
101 		/* we haven't locked out transactions, so a commit
102 		 * could've happened. Since we've got a reference on
103 		 * the bh, even if it commits while we're doing the
104 		 * copy, the data is still good. */
105 		if (buffer_jbd(buffer_cache_bh)
106 		    && ocfs2_inode_is_new(inode)) {
107 			kaddr = kmap_atomic(bh_result->b_page);
108 			if (!kaddr) {
109 				mlog(ML_ERROR, "couldn't kmap!\n");
110 				goto bail;
111 			}
112 			memcpy(kaddr + (bh_result->b_size * iblock),
113 			       buffer_cache_bh->b_data,
114 			       bh_result->b_size);
115 			kunmap_atomic(kaddr);
116 			set_buffer_uptodate(bh_result);
117 		}
118 		brelse(buffer_cache_bh);
119 	}
120 
121 	map_bh(bh_result, inode->i_sb,
122 	       le64_to_cpu(fe->id2.i_list.l_recs[0].e_blkno) + iblock);
123 
124 	err = 0;
125 
126 bail:
127 	brelse(bh);
128 
129 	return err;
130 }
131 
132 int ocfs2_get_block(struct inode *inode, sector_t iblock,
133 		    struct buffer_head *bh_result, int create)
134 {
135 	int err = 0;
136 	unsigned int ext_flags;
137 	u64 max_blocks = bh_result->b_size >> inode->i_blkbits;
138 	u64 p_blkno, count, past_eof;
139 	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
140 
141 	trace_ocfs2_get_block((unsigned long long)OCFS2_I(inode)->ip_blkno,
142 			      (unsigned long long)iblock, bh_result, create);
143 
144 	if (OCFS2_I(inode)->ip_flags & OCFS2_INODE_SYSTEM_FILE)
145 		mlog(ML_NOTICE, "get_block on system inode 0x%p (%lu)\n",
146 		     inode, inode->i_ino);
147 
148 	if (S_ISLNK(inode->i_mode)) {
149 		/* this always does I/O for some reason. */
150 		err = ocfs2_symlink_get_block(inode, iblock, bh_result, create);
151 		goto bail;
152 	}
153 
154 	err = ocfs2_extent_map_get_blocks(inode, iblock, &p_blkno, &count,
155 					  &ext_flags);
156 	if (err) {
157 		mlog(ML_ERROR, "Error %d from get_blocks(0x%p, %llu, 1, "
158 		     "%llu, NULL)\n", err, inode, (unsigned long long)iblock,
159 		     (unsigned long long)p_blkno);
160 		goto bail;
161 	}
162 
163 	if (max_blocks < count)
164 		count = max_blocks;
165 
166 	/*
167 	 * ocfs2 never allocates in this function - the only time we
168 	 * need to use BH_New is when we're extending i_size on a file
169 	 * system which doesn't support holes, in which case BH_New
170 	 * allows __block_write_begin() to zero.
171 	 *
172 	 * If we see this on a sparse file system, then a truncate has
173 	 * raced us and removed the cluster. In this case, we clear
174 	 * the buffers dirty and uptodate bits and let the buffer code
175 	 * ignore it as a hole.
176 	 */
177 	if (create && p_blkno == 0 && ocfs2_sparse_alloc(osb)) {
178 		clear_buffer_dirty(bh_result);
179 		clear_buffer_uptodate(bh_result);
180 		goto bail;
181 	}
182 
183 	/* Treat the unwritten extent as a hole for zeroing purposes. */
184 	if (p_blkno && !(ext_flags & OCFS2_EXT_UNWRITTEN))
185 		map_bh(bh_result, inode->i_sb, p_blkno);
186 
187 	bh_result->b_size = count << inode->i_blkbits;
188 
189 	if (!ocfs2_sparse_alloc(osb)) {
190 		if (p_blkno == 0) {
191 			err = -EIO;
192 			mlog(ML_ERROR,
193 			     "iblock = %llu p_blkno = %llu blkno=(%llu)\n",
194 			     (unsigned long long)iblock,
195 			     (unsigned long long)p_blkno,
196 			     (unsigned long long)OCFS2_I(inode)->ip_blkno);
197 			mlog(ML_ERROR, "Size %llu, clusters %u\n", (unsigned long long)i_size_read(inode), OCFS2_I(inode)->ip_clusters);
198 			dump_stack();
199 			goto bail;
200 		}
201 	}
202 
203 	past_eof = ocfs2_blocks_for_bytes(inode->i_sb, i_size_read(inode));
204 
205 	trace_ocfs2_get_block_end((unsigned long long)OCFS2_I(inode)->ip_blkno,
206 				  (unsigned long long)past_eof);
207 	if (create && (iblock >= past_eof))
208 		set_buffer_new(bh_result);
209 
210 bail:
211 	if (err < 0)
212 		err = -EIO;
213 
214 	return err;
215 }
216 
217 int ocfs2_read_inline_data(struct inode *inode, struct page *page,
218 			   struct buffer_head *di_bh)
219 {
220 	void *kaddr;
221 	loff_t size;
222 	struct ocfs2_dinode *di = (struct ocfs2_dinode *)di_bh->b_data;
223 
224 	if (!(le16_to_cpu(di->i_dyn_features) & OCFS2_INLINE_DATA_FL)) {
225 		ocfs2_error(inode->i_sb, "Inode %llu lost inline data flag",
226 			    (unsigned long long)OCFS2_I(inode)->ip_blkno);
227 		return -EROFS;
228 	}
229 
230 	size = i_size_read(inode);
231 
232 	if (size > PAGE_CACHE_SIZE ||
233 	    size > ocfs2_max_inline_data_with_xattr(inode->i_sb, di)) {
234 		ocfs2_error(inode->i_sb,
235 			    "Inode %llu has with inline data has bad size: %Lu",
236 			    (unsigned long long)OCFS2_I(inode)->ip_blkno,
237 			    (unsigned long long)size);
238 		return -EROFS;
239 	}
240 
241 	kaddr = kmap_atomic(page);
242 	if (size)
243 		memcpy(kaddr, di->id2.i_data.id_data, size);
244 	/* Clear the remaining part of the page */
245 	memset(kaddr + size, 0, PAGE_CACHE_SIZE - size);
246 	flush_dcache_page(page);
247 	kunmap_atomic(kaddr);
248 
249 	SetPageUptodate(page);
250 
251 	return 0;
252 }
253 
254 static int ocfs2_readpage_inline(struct inode *inode, struct page *page)
255 {
256 	int ret;
257 	struct buffer_head *di_bh = NULL;
258 
259 	BUG_ON(!PageLocked(page));
260 	BUG_ON(!(OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL));
261 
262 	ret = ocfs2_read_inode_block(inode, &di_bh);
263 	if (ret) {
264 		mlog_errno(ret);
265 		goto out;
266 	}
267 
268 	ret = ocfs2_read_inline_data(inode, page, di_bh);
269 out:
270 	unlock_page(page);
271 
272 	brelse(di_bh);
273 	return ret;
274 }
275 
276 static int ocfs2_readpage(struct file *file, struct page *page)
277 {
278 	struct inode *inode = page->mapping->host;
279 	struct ocfs2_inode_info *oi = OCFS2_I(inode);
280 	loff_t start = (loff_t)page->index << PAGE_CACHE_SHIFT;
281 	int ret, unlock = 1;
282 
283 	trace_ocfs2_readpage((unsigned long long)oi->ip_blkno,
284 			     (page ? page->index : 0));
285 
286 	ret = ocfs2_inode_lock_with_page(inode, NULL, 0, page);
287 	if (ret != 0) {
288 		if (ret == AOP_TRUNCATED_PAGE)
289 			unlock = 0;
290 		mlog_errno(ret);
291 		goto out;
292 	}
293 
294 	if (down_read_trylock(&oi->ip_alloc_sem) == 0) {
295 		/*
296 		 * Unlock the page and cycle ip_alloc_sem so that we don't
297 		 * busyloop waiting for ip_alloc_sem to unlock
298 		 */
299 		ret = AOP_TRUNCATED_PAGE;
300 		unlock_page(page);
301 		unlock = 0;
302 		down_read(&oi->ip_alloc_sem);
303 		up_read(&oi->ip_alloc_sem);
304 		goto out_inode_unlock;
305 	}
306 
307 	/*
308 	 * i_size might have just been updated as we grabed the meta lock.  We
309 	 * might now be discovering a truncate that hit on another node.
310 	 * block_read_full_page->get_block freaks out if it is asked to read
311 	 * beyond the end of a file, so we check here.  Callers
312 	 * (generic_file_read, vm_ops->fault) are clever enough to check i_size
313 	 * and notice that the page they just read isn't needed.
314 	 *
315 	 * XXX sys_readahead() seems to get that wrong?
316 	 */
317 	if (start >= i_size_read(inode)) {
318 		zero_user(page, 0, PAGE_SIZE);
319 		SetPageUptodate(page);
320 		ret = 0;
321 		goto out_alloc;
322 	}
323 
324 	if (oi->ip_dyn_features & OCFS2_INLINE_DATA_FL)
325 		ret = ocfs2_readpage_inline(inode, page);
326 	else
327 		ret = block_read_full_page(page, ocfs2_get_block);
328 	unlock = 0;
329 
330 out_alloc:
331 	up_read(&OCFS2_I(inode)->ip_alloc_sem);
332 out_inode_unlock:
333 	ocfs2_inode_unlock(inode, 0);
334 out:
335 	if (unlock)
336 		unlock_page(page);
337 	return ret;
338 }
339 
340 /*
341  * This is used only for read-ahead. Failures or difficult to handle
342  * situations are safe to ignore.
343  *
344  * Right now, we don't bother with BH_Boundary - in-inode extent lists
345  * are quite large (243 extents on 4k blocks), so most inodes don't
346  * grow out to a tree. If need be, detecting boundary extents could
347  * trivially be added in a future version of ocfs2_get_block().
348  */
349 static int ocfs2_readpages(struct file *filp, struct address_space *mapping,
350 			   struct list_head *pages, unsigned nr_pages)
351 {
352 	int ret, err = -EIO;
353 	struct inode *inode = mapping->host;
354 	struct ocfs2_inode_info *oi = OCFS2_I(inode);
355 	loff_t start;
356 	struct page *last;
357 
358 	/*
359 	 * Use the nonblocking flag for the dlm code to avoid page
360 	 * lock inversion, but don't bother with retrying.
361 	 */
362 	ret = ocfs2_inode_lock_full(inode, NULL, 0, OCFS2_LOCK_NONBLOCK);
363 	if (ret)
364 		return err;
365 
366 	if (down_read_trylock(&oi->ip_alloc_sem) == 0) {
367 		ocfs2_inode_unlock(inode, 0);
368 		return err;
369 	}
370 
371 	/*
372 	 * Don't bother with inline-data. There isn't anything
373 	 * to read-ahead in that case anyway...
374 	 */
375 	if (oi->ip_dyn_features & OCFS2_INLINE_DATA_FL)
376 		goto out_unlock;
377 
378 	/*
379 	 * Check whether a remote node truncated this file - we just
380 	 * drop out in that case as it's not worth handling here.
381 	 */
382 	last = list_entry(pages->prev, struct page, lru);
383 	start = (loff_t)last->index << PAGE_CACHE_SHIFT;
384 	if (start >= i_size_read(inode))
385 		goto out_unlock;
386 
387 	err = mpage_readpages(mapping, pages, nr_pages, ocfs2_get_block);
388 
389 out_unlock:
390 	up_read(&oi->ip_alloc_sem);
391 	ocfs2_inode_unlock(inode, 0);
392 
393 	return err;
394 }
395 
396 /* Note: Because we don't support holes, our allocation has
397  * already happened (allocation writes zeros to the file data)
398  * so we don't have to worry about ordered writes in
399  * ocfs2_writepage.
400  *
401  * ->writepage is called during the process of invalidating the page cache
402  * during blocked lock processing.  It can't block on any cluster locks
403  * to during block mapping.  It's relying on the fact that the block
404  * mapping can't have disappeared under the dirty pages that it is
405  * being asked to write back.
406  */
407 static int ocfs2_writepage(struct page *page, struct writeback_control *wbc)
408 {
409 	trace_ocfs2_writepage(
410 		(unsigned long long)OCFS2_I(page->mapping->host)->ip_blkno,
411 		page->index);
412 
413 	return block_write_full_page(page, ocfs2_get_block, wbc);
414 }
415 
416 /* Taken from ext3. We don't necessarily need the full blown
417  * functionality yet, but IMHO it's better to cut and paste the whole
418  * thing so we can avoid introducing our own bugs (and easily pick up
419  * their fixes when they happen) --Mark */
420 int walk_page_buffers(	handle_t *handle,
421 			struct buffer_head *head,
422 			unsigned from,
423 			unsigned to,
424 			int *partial,
425 			int (*fn)(	handle_t *handle,
426 					struct buffer_head *bh))
427 {
428 	struct buffer_head *bh;
429 	unsigned block_start, block_end;
430 	unsigned blocksize = head->b_size;
431 	int err, ret = 0;
432 	struct buffer_head *next;
433 
434 	for (	bh = head, block_start = 0;
435 		ret == 0 && (bh != head || !block_start);
436 	    	block_start = block_end, bh = next)
437 	{
438 		next = bh->b_this_page;
439 		block_end = block_start + blocksize;
440 		if (block_end <= from || block_start >= to) {
441 			if (partial && !buffer_uptodate(bh))
442 				*partial = 1;
443 			continue;
444 		}
445 		err = (*fn)(handle, bh);
446 		if (!ret)
447 			ret = err;
448 	}
449 	return ret;
450 }
451 
452 static sector_t ocfs2_bmap(struct address_space *mapping, sector_t block)
453 {
454 	sector_t status;
455 	u64 p_blkno = 0;
456 	int err = 0;
457 	struct inode *inode = mapping->host;
458 
459 	trace_ocfs2_bmap((unsigned long long)OCFS2_I(inode)->ip_blkno,
460 			 (unsigned long long)block);
461 
462 	/* We don't need to lock journal system files, since they aren't
463 	 * accessed concurrently from multiple nodes.
464 	 */
465 	if (!INODE_JOURNAL(inode)) {
466 		err = ocfs2_inode_lock(inode, NULL, 0);
467 		if (err) {
468 			if (err != -ENOENT)
469 				mlog_errno(err);
470 			goto bail;
471 		}
472 		down_read(&OCFS2_I(inode)->ip_alloc_sem);
473 	}
474 
475 	if (!(OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL))
476 		err = ocfs2_extent_map_get_blocks(inode, block, &p_blkno, NULL,
477 						  NULL);
478 
479 	if (!INODE_JOURNAL(inode)) {
480 		up_read(&OCFS2_I(inode)->ip_alloc_sem);
481 		ocfs2_inode_unlock(inode, 0);
482 	}
483 
484 	if (err) {
485 		mlog(ML_ERROR, "get_blocks() failed, block = %llu\n",
486 		     (unsigned long long)block);
487 		mlog_errno(err);
488 		goto bail;
489 	}
490 
491 bail:
492 	status = err ? 0 : p_blkno;
493 
494 	return status;
495 }
496 
497 /*
498  * TODO: Make this into a generic get_blocks function.
499  *
500  * From do_direct_io in direct-io.c:
501  *  "So what we do is to permit the ->get_blocks function to populate
502  *   bh.b_size with the size of IO which is permitted at this offset and
503  *   this i_blkbits."
504  *
505  * This function is called directly from get_more_blocks in direct-io.c.
506  *
507  * called like this: dio->get_blocks(dio->inode, fs_startblk,
508  * 					fs_count, map_bh, dio->rw == WRITE);
509  *
510  * Note that we never bother to allocate blocks here, and thus ignore the
511  * create argument.
512  */
513 static int ocfs2_direct_IO_get_blocks(struct inode *inode, sector_t iblock,
514 				     struct buffer_head *bh_result, int create)
515 {
516 	int ret;
517 	u64 p_blkno, inode_blocks, contig_blocks;
518 	unsigned int ext_flags;
519 	unsigned char blocksize_bits = inode->i_sb->s_blocksize_bits;
520 	unsigned long max_blocks = bh_result->b_size >> inode->i_blkbits;
521 
522 	/* This function won't even be called if the request isn't all
523 	 * nicely aligned and of the right size, so there's no need
524 	 * for us to check any of that. */
525 
526 	inode_blocks = ocfs2_blocks_for_bytes(inode->i_sb, i_size_read(inode));
527 
528 	/* This figures out the size of the next contiguous block, and
529 	 * our logical offset */
530 	ret = ocfs2_extent_map_get_blocks(inode, iblock, &p_blkno,
531 					  &contig_blocks, &ext_flags);
532 	if (ret) {
533 		mlog(ML_ERROR, "get_blocks() failed iblock=%llu\n",
534 		     (unsigned long long)iblock);
535 		ret = -EIO;
536 		goto bail;
537 	}
538 
539 	/* We should already CoW the refcounted extent in case of create. */
540 	BUG_ON(create && (ext_flags & OCFS2_EXT_REFCOUNTED));
541 
542 	/*
543 	 * get_more_blocks() expects us to describe a hole by clearing
544 	 * the mapped bit on bh_result().
545 	 *
546 	 * Consider an unwritten extent as a hole.
547 	 */
548 	if (p_blkno && !(ext_flags & OCFS2_EXT_UNWRITTEN))
549 		map_bh(bh_result, inode->i_sb, p_blkno);
550 	else
551 		clear_buffer_mapped(bh_result);
552 
553 	/* make sure we don't map more than max_blocks blocks here as
554 	   that's all the kernel will handle at this point. */
555 	if (max_blocks < contig_blocks)
556 		contig_blocks = max_blocks;
557 	bh_result->b_size = contig_blocks << blocksize_bits;
558 bail:
559 	return ret;
560 }
561 
562 /*
563  * ocfs2_dio_end_io is called by the dio core when a dio is finished.  We're
564  * particularly interested in the aio/dio case.  We use the rw_lock DLM lock
565  * to protect io on one node from truncation on another.
566  */
567 static void ocfs2_dio_end_io(struct kiocb *iocb,
568 			     loff_t offset,
569 			     ssize_t bytes,
570 			     void *private)
571 {
572 	struct inode *inode = file_inode(iocb->ki_filp);
573 	int level;
574 
575 	/* this io's submitter should not have unlocked this before we could */
576 	BUG_ON(!ocfs2_iocb_is_rw_locked(iocb));
577 
578 	if (ocfs2_iocb_is_sem_locked(iocb))
579 		ocfs2_iocb_clear_sem_locked(iocb);
580 
581 	if (ocfs2_iocb_is_unaligned_aio(iocb)) {
582 		ocfs2_iocb_clear_unaligned_aio(iocb);
583 
584 		mutex_unlock(&OCFS2_I(inode)->ip_unaligned_aio);
585 	}
586 
587 	ocfs2_iocb_clear_rw_locked(iocb);
588 
589 	level = ocfs2_iocb_rw_locked_level(iocb);
590 	ocfs2_rw_unlock(inode, level);
591 }
592 
593 static int ocfs2_releasepage(struct page *page, gfp_t wait)
594 {
595 	if (!page_has_buffers(page))
596 		return 0;
597 	return try_to_free_buffers(page);
598 }
599 
600 static ssize_t ocfs2_direct_IO(int rw,
601 			       struct kiocb *iocb,
602 			       const struct iovec *iov,
603 			       loff_t offset,
604 			       unsigned long nr_segs)
605 {
606 	struct file *file = iocb->ki_filp;
607 	struct inode *inode = file_inode(file)->i_mapping->host;
608 
609 	/*
610 	 * Fallback to buffered I/O if we see an inode without
611 	 * extents.
612 	 */
613 	if (OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL)
614 		return 0;
615 
616 	/* Fallback to buffered I/O if we are appending. */
617 	if (i_size_read(inode) <= offset)
618 		return 0;
619 
620 	return __blockdev_direct_IO(rw, iocb, inode, inode->i_sb->s_bdev,
621 				    iov, offset, nr_segs,
622 				    ocfs2_direct_IO_get_blocks,
623 				    ocfs2_dio_end_io, NULL, 0);
624 }
625 
626 static void ocfs2_figure_cluster_boundaries(struct ocfs2_super *osb,
627 					    u32 cpos,
628 					    unsigned int *start,
629 					    unsigned int *end)
630 {
631 	unsigned int cluster_start = 0, cluster_end = PAGE_CACHE_SIZE;
632 
633 	if (unlikely(PAGE_CACHE_SHIFT > osb->s_clustersize_bits)) {
634 		unsigned int cpp;
635 
636 		cpp = 1 << (PAGE_CACHE_SHIFT - osb->s_clustersize_bits);
637 
638 		cluster_start = cpos % cpp;
639 		cluster_start = cluster_start << osb->s_clustersize_bits;
640 
641 		cluster_end = cluster_start + osb->s_clustersize;
642 	}
643 
644 	BUG_ON(cluster_start > PAGE_SIZE);
645 	BUG_ON(cluster_end > PAGE_SIZE);
646 
647 	if (start)
648 		*start = cluster_start;
649 	if (end)
650 		*end = cluster_end;
651 }
652 
653 /*
654  * 'from' and 'to' are the region in the page to avoid zeroing.
655  *
656  * If pagesize > clustersize, this function will avoid zeroing outside
657  * of the cluster boundary.
658  *
659  * from == to == 0 is code for "zero the entire cluster region"
660  */
661 static void ocfs2_clear_page_regions(struct page *page,
662 				     struct ocfs2_super *osb, u32 cpos,
663 				     unsigned from, unsigned to)
664 {
665 	void *kaddr;
666 	unsigned int cluster_start, cluster_end;
667 
668 	ocfs2_figure_cluster_boundaries(osb, cpos, &cluster_start, &cluster_end);
669 
670 	kaddr = kmap_atomic(page);
671 
672 	if (from || to) {
673 		if (from > cluster_start)
674 			memset(kaddr + cluster_start, 0, from - cluster_start);
675 		if (to < cluster_end)
676 			memset(kaddr + to, 0, cluster_end - to);
677 	} else {
678 		memset(kaddr + cluster_start, 0, cluster_end - cluster_start);
679 	}
680 
681 	kunmap_atomic(kaddr);
682 }
683 
684 /*
685  * Nonsparse file systems fully allocate before we get to the write
686  * code. This prevents ocfs2_write() from tagging the write as an
687  * allocating one, which means ocfs2_map_page_blocks() might try to
688  * read-in the blocks at the tail of our file. Avoid reading them by
689  * testing i_size against each block offset.
690  */
691 static int ocfs2_should_read_blk(struct inode *inode, struct page *page,
692 				 unsigned int block_start)
693 {
694 	u64 offset = page_offset(page) + block_start;
695 
696 	if (ocfs2_sparse_alloc(OCFS2_SB(inode->i_sb)))
697 		return 1;
698 
699 	if (i_size_read(inode) > offset)
700 		return 1;
701 
702 	return 0;
703 }
704 
705 /*
706  * Some of this taken from __block_write_begin(). We already have our
707  * mapping by now though, and the entire write will be allocating or
708  * it won't, so not much need to use BH_New.
709  *
710  * This will also skip zeroing, which is handled externally.
711  */
712 int ocfs2_map_page_blocks(struct page *page, u64 *p_blkno,
713 			  struct inode *inode, unsigned int from,
714 			  unsigned int to, int new)
715 {
716 	int ret = 0;
717 	struct buffer_head *head, *bh, *wait[2], **wait_bh = wait;
718 	unsigned int block_end, block_start;
719 	unsigned int bsize = 1 << inode->i_blkbits;
720 
721 	if (!page_has_buffers(page))
722 		create_empty_buffers(page, bsize, 0);
723 
724 	head = page_buffers(page);
725 	for (bh = head, block_start = 0; bh != head || !block_start;
726 	     bh = bh->b_this_page, block_start += bsize) {
727 		block_end = block_start + bsize;
728 
729 		clear_buffer_new(bh);
730 
731 		/*
732 		 * Ignore blocks outside of our i/o range -
733 		 * they may belong to unallocated clusters.
734 		 */
735 		if (block_start >= to || block_end <= from) {
736 			if (PageUptodate(page))
737 				set_buffer_uptodate(bh);
738 			continue;
739 		}
740 
741 		/*
742 		 * For an allocating write with cluster size >= page
743 		 * size, we always write the entire page.
744 		 */
745 		if (new)
746 			set_buffer_new(bh);
747 
748 		if (!buffer_mapped(bh)) {
749 			map_bh(bh, inode->i_sb, *p_blkno);
750 			unmap_underlying_metadata(bh->b_bdev, bh->b_blocknr);
751 		}
752 
753 		if (PageUptodate(page)) {
754 			if (!buffer_uptodate(bh))
755 				set_buffer_uptodate(bh);
756 		} else if (!buffer_uptodate(bh) && !buffer_delay(bh) &&
757 			   !buffer_new(bh) &&
758 			   ocfs2_should_read_blk(inode, page, block_start) &&
759 			   (block_start < from || block_end > to)) {
760 			ll_rw_block(READ, 1, &bh);
761 			*wait_bh++=bh;
762 		}
763 
764 		*p_blkno = *p_blkno + 1;
765 	}
766 
767 	/*
768 	 * If we issued read requests - let them complete.
769 	 */
770 	while(wait_bh > wait) {
771 		wait_on_buffer(*--wait_bh);
772 		if (!buffer_uptodate(*wait_bh))
773 			ret = -EIO;
774 	}
775 
776 	if (ret == 0 || !new)
777 		return ret;
778 
779 	/*
780 	 * If we get -EIO above, zero out any newly allocated blocks
781 	 * to avoid exposing stale data.
782 	 */
783 	bh = head;
784 	block_start = 0;
785 	do {
786 		block_end = block_start + bsize;
787 		if (block_end <= from)
788 			goto next_bh;
789 		if (block_start >= to)
790 			break;
791 
792 		zero_user(page, block_start, bh->b_size);
793 		set_buffer_uptodate(bh);
794 		mark_buffer_dirty(bh);
795 
796 next_bh:
797 		block_start = block_end;
798 		bh = bh->b_this_page;
799 	} while (bh != head);
800 
801 	return ret;
802 }
803 
804 #if (PAGE_CACHE_SIZE >= OCFS2_MAX_CLUSTERSIZE)
805 #define OCFS2_MAX_CTXT_PAGES	1
806 #else
807 #define OCFS2_MAX_CTXT_PAGES	(OCFS2_MAX_CLUSTERSIZE / PAGE_CACHE_SIZE)
808 #endif
809 
810 #define OCFS2_MAX_CLUSTERS_PER_PAGE	(PAGE_CACHE_SIZE / OCFS2_MIN_CLUSTERSIZE)
811 
812 /*
813  * Describe the state of a single cluster to be written to.
814  */
815 struct ocfs2_write_cluster_desc {
816 	u32		c_cpos;
817 	u32		c_phys;
818 	/*
819 	 * Give this a unique field because c_phys eventually gets
820 	 * filled.
821 	 */
822 	unsigned	c_new;
823 	unsigned	c_unwritten;
824 	unsigned	c_needs_zero;
825 };
826 
827 struct ocfs2_write_ctxt {
828 	/* Logical cluster position / len of write */
829 	u32				w_cpos;
830 	u32				w_clen;
831 
832 	/* First cluster allocated in a nonsparse extend */
833 	u32				w_first_new_cpos;
834 
835 	struct ocfs2_write_cluster_desc	w_desc[OCFS2_MAX_CLUSTERS_PER_PAGE];
836 
837 	/*
838 	 * This is true if page_size > cluster_size.
839 	 *
840 	 * It triggers a set of special cases during write which might
841 	 * have to deal with allocating writes to partial pages.
842 	 */
843 	unsigned int			w_large_pages;
844 
845 	/*
846 	 * Pages involved in this write.
847 	 *
848 	 * w_target_page is the page being written to by the user.
849 	 *
850 	 * w_pages is an array of pages which always contains
851 	 * w_target_page, and in the case of an allocating write with
852 	 * page_size < cluster size, it will contain zero'd and mapped
853 	 * pages adjacent to w_target_page which need to be written
854 	 * out in so that future reads from that region will get
855 	 * zero's.
856 	 */
857 	unsigned int			w_num_pages;
858 	struct page			*w_pages[OCFS2_MAX_CTXT_PAGES];
859 	struct page			*w_target_page;
860 
861 	/*
862 	 * w_target_locked is used for page_mkwrite path indicating no unlocking
863 	 * against w_target_page in ocfs2_write_end_nolock.
864 	 */
865 	unsigned int			w_target_locked:1;
866 
867 	/*
868 	 * ocfs2_write_end() uses this to know what the real range to
869 	 * write in the target should be.
870 	 */
871 	unsigned int			w_target_from;
872 	unsigned int			w_target_to;
873 
874 	/*
875 	 * We could use journal_current_handle() but this is cleaner,
876 	 * IMHO -Mark
877 	 */
878 	handle_t			*w_handle;
879 
880 	struct buffer_head		*w_di_bh;
881 
882 	struct ocfs2_cached_dealloc_ctxt w_dealloc;
883 };
884 
885 void ocfs2_unlock_and_free_pages(struct page **pages, int num_pages)
886 {
887 	int i;
888 
889 	for(i = 0; i < num_pages; i++) {
890 		if (pages[i]) {
891 			unlock_page(pages[i]);
892 			mark_page_accessed(pages[i]);
893 			page_cache_release(pages[i]);
894 		}
895 	}
896 }
897 
898 static void ocfs2_free_write_ctxt(struct ocfs2_write_ctxt *wc)
899 {
900 	int i;
901 
902 	/*
903 	 * w_target_locked is only set to true in the page_mkwrite() case.
904 	 * The intent is to allow us to lock the target page from write_begin()
905 	 * to write_end(). The caller must hold a ref on w_target_page.
906 	 */
907 	if (wc->w_target_locked) {
908 		BUG_ON(!wc->w_target_page);
909 		for (i = 0; i < wc->w_num_pages; i++) {
910 			if (wc->w_target_page == wc->w_pages[i]) {
911 				wc->w_pages[i] = NULL;
912 				break;
913 			}
914 		}
915 		mark_page_accessed(wc->w_target_page);
916 		page_cache_release(wc->w_target_page);
917 	}
918 	ocfs2_unlock_and_free_pages(wc->w_pages, wc->w_num_pages);
919 
920 	brelse(wc->w_di_bh);
921 	kfree(wc);
922 }
923 
924 static int ocfs2_alloc_write_ctxt(struct ocfs2_write_ctxt **wcp,
925 				  struct ocfs2_super *osb, loff_t pos,
926 				  unsigned len, struct buffer_head *di_bh)
927 {
928 	u32 cend;
929 	struct ocfs2_write_ctxt *wc;
930 
931 	wc = kzalloc(sizeof(struct ocfs2_write_ctxt), GFP_NOFS);
932 	if (!wc)
933 		return -ENOMEM;
934 
935 	wc->w_cpos = pos >> osb->s_clustersize_bits;
936 	wc->w_first_new_cpos = UINT_MAX;
937 	cend = (pos + len - 1) >> osb->s_clustersize_bits;
938 	wc->w_clen = cend - wc->w_cpos + 1;
939 	get_bh(di_bh);
940 	wc->w_di_bh = di_bh;
941 
942 	if (unlikely(PAGE_CACHE_SHIFT > osb->s_clustersize_bits))
943 		wc->w_large_pages = 1;
944 	else
945 		wc->w_large_pages = 0;
946 
947 	ocfs2_init_dealloc_ctxt(&wc->w_dealloc);
948 
949 	*wcp = wc;
950 
951 	return 0;
952 }
953 
954 /*
955  * If a page has any new buffers, zero them out here, and mark them uptodate
956  * and dirty so they'll be written out (in order to prevent uninitialised
957  * block data from leaking). And clear the new bit.
958  */
959 static void ocfs2_zero_new_buffers(struct page *page, unsigned from, unsigned to)
960 {
961 	unsigned int block_start, block_end;
962 	struct buffer_head *head, *bh;
963 
964 	BUG_ON(!PageLocked(page));
965 	if (!page_has_buffers(page))
966 		return;
967 
968 	bh = head = page_buffers(page);
969 	block_start = 0;
970 	do {
971 		block_end = block_start + bh->b_size;
972 
973 		if (buffer_new(bh)) {
974 			if (block_end > from && block_start < to) {
975 				if (!PageUptodate(page)) {
976 					unsigned start, end;
977 
978 					start = max(from, block_start);
979 					end = min(to, block_end);
980 
981 					zero_user_segment(page, start, end);
982 					set_buffer_uptodate(bh);
983 				}
984 
985 				clear_buffer_new(bh);
986 				mark_buffer_dirty(bh);
987 			}
988 		}
989 
990 		block_start = block_end;
991 		bh = bh->b_this_page;
992 	} while (bh != head);
993 }
994 
995 /*
996  * Only called when we have a failure during allocating write to write
997  * zero's to the newly allocated region.
998  */
999 static void ocfs2_write_failure(struct inode *inode,
1000 				struct ocfs2_write_ctxt *wc,
1001 				loff_t user_pos, unsigned user_len)
1002 {
1003 	int i;
1004 	unsigned from = user_pos & (PAGE_CACHE_SIZE - 1),
1005 		to = user_pos + user_len;
1006 	struct page *tmppage;
1007 
1008 	ocfs2_zero_new_buffers(wc->w_target_page, from, to);
1009 
1010 	for(i = 0; i < wc->w_num_pages; i++) {
1011 		tmppage = wc->w_pages[i];
1012 
1013 		if (page_has_buffers(tmppage)) {
1014 			if (ocfs2_should_order_data(inode))
1015 				ocfs2_jbd2_file_inode(wc->w_handle, inode);
1016 
1017 			block_commit_write(tmppage, from, to);
1018 		}
1019 	}
1020 }
1021 
1022 static int ocfs2_prepare_page_for_write(struct inode *inode, u64 *p_blkno,
1023 					struct ocfs2_write_ctxt *wc,
1024 					struct page *page, u32 cpos,
1025 					loff_t user_pos, unsigned user_len,
1026 					int new)
1027 {
1028 	int ret;
1029 	unsigned int map_from = 0, map_to = 0;
1030 	unsigned int cluster_start, cluster_end;
1031 	unsigned int user_data_from = 0, user_data_to = 0;
1032 
1033 	ocfs2_figure_cluster_boundaries(OCFS2_SB(inode->i_sb), cpos,
1034 					&cluster_start, &cluster_end);
1035 
1036 	/* treat the write as new if the a hole/lseek spanned across
1037 	 * the page boundary.
1038 	 */
1039 	new = new | ((i_size_read(inode) <= page_offset(page)) &&
1040 			(page_offset(page) <= user_pos));
1041 
1042 	if (page == wc->w_target_page) {
1043 		map_from = user_pos & (PAGE_CACHE_SIZE - 1);
1044 		map_to = map_from + user_len;
1045 
1046 		if (new)
1047 			ret = ocfs2_map_page_blocks(page, p_blkno, inode,
1048 						    cluster_start, cluster_end,
1049 						    new);
1050 		else
1051 			ret = ocfs2_map_page_blocks(page, p_blkno, inode,
1052 						    map_from, map_to, new);
1053 		if (ret) {
1054 			mlog_errno(ret);
1055 			goto out;
1056 		}
1057 
1058 		user_data_from = map_from;
1059 		user_data_to = map_to;
1060 		if (new) {
1061 			map_from = cluster_start;
1062 			map_to = cluster_end;
1063 		}
1064 	} else {
1065 		/*
1066 		 * If we haven't allocated the new page yet, we
1067 		 * shouldn't be writing it out without copying user
1068 		 * data. This is likely a math error from the caller.
1069 		 */
1070 		BUG_ON(!new);
1071 
1072 		map_from = cluster_start;
1073 		map_to = cluster_end;
1074 
1075 		ret = ocfs2_map_page_blocks(page, p_blkno, inode,
1076 					    cluster_start, cluster_end, new);
1077 		if (ret) {
1078 			mlog_errno(ret);
1079 			goto out;
1080 		}
1081 	}
1082 
1083 	/*
1084 	 * Parts of newly allocated pages need to be zero'd.
1085 	 *
1086 	 * Above, we have also rewritten 'to' and 'from' - as far as
1087 	 * the rest of the function is concerned, the entire cluster
1088 	 * range inside of a page needs to be written.
1089 	 *
1090 	 * We can skip this if the page is up to date - it's already
1091 	 * been zero'd from being read in as a hole.
1092 	 */
1093 	if (new && !PageUptodate(page))
1094 		ocfs2_clear_page_regions(page, OCFS2_SB(inode->i_sb),
1095 					 cpos, user_data_from, user_data_to);
1096 
1097 	flush_dcache_page(page);
1098 
1099 out:
1100 	return ret;
1101 }
1102 
1103 /*
1104  * This function will only grab one clusters worth of pages.
1105  */
1106 static int ocfs2_grab_pages_for_write(struct address_space *mapping,
1107 				      struct ocfs2_write_ctxt *wc,
1108 				      u32 cpos, loff_t user_pos,
1109 				      unsigned user_len, int new,
1110 				      struct page *mmap_page)
1111 {
1112 	int ret = 0, i;
1113 	unsigned long start, target_index, end_index, index;
1114 	struct inode *inode = mapping->host;
1115 	loff_t last_byte;
1116 
1117 	target_index = user_pos >> PAGE_CACHE_SHIFT;
1118 
1119 	/*
1120 	 * Figure out how many pages we'll be manipulating here. For
1121 	 * non allocating write, we just change the one
1122 	 * page. Otherwise, we'll need a whole clusters worth.  If we're
1123 	 * writing past i_size, we only need enough pages to cover the
1124 	 * last page of the write.
1125 	 */
1126 	if (new) {
1127 		wc->w_num_pages = ocfs2_pages_per_cluster(inode->i_sb);
1128 		start = ocfs2_align_clusters_to_page_index(inode->i_sb, cpos);
1129 		/*
1130 		 * We need the index *past* the last page we could possibly
1131 		 * touch.  This is the page past the end of the write or
1132 		 * i_size, whichever is greater.
1133 		 */
1134 		last_byte = max(user_pos + user_len, i_size_read(inode));
1135 		BUG_ON(last_byte < 1);
1136 		end_index = ((last_byte - 1) >> PAGE_CACHE_SHIFT) + 1;
1137 		if ((start + wc->w_num_pages) > end_index)
1138 			wc->w_num_pages = end_index - start;
1139 	} else {
1140 		wc->w_num_pages = 1;
1141 		start = target_index;
1142 	}
1143 
1144 	for(i = 0; i < wc->w_num_pages; i++) {
1145 		index = start + i;
1146 
1147 		if (index == target_index && mmap_page) {
1148 			/*
1149 			 * ocfs2_pagemkwrite() is a little different
1150 			 * and wants us to directly use the page
1151 			 * passed in.
1152 			 */
1153 			lock_page(mmap_page);
1154 
1155 			/* Exit and let the caller retry */
1156 			if (mmap_page->mapping != mapping) {
1157 				WARN_ON(mmap_page->mapping);
1158 				unlock_page(mmap_page);
1159 				ret = -EAGAIN;
1160 				goto out;
1161 			}
1162 
1163 			page_cache_get(mmap_page);
1164 			wc->w_pages[i] = mmap_page;
1165 			wc->w_target_locked = true;
1166 		} else {
1167 			wc->w_pages[i] = find_or_create_page(mapping, index,
1168 							     GFP_NOFS);
1169 			if (!wc->w_pages[i]) {
1170 				ret = -ENOMEM;
1171 				mlog_errno(ret);
1172 				goto out;
1173 			}
1174 		}
1175 		wait_for_stable_page(wc->w_pages[i]);
1176 
1177 		if (index == target_index)
1178 			wc->w_target_page = wc->w_pages[i];
1179 	}
1180 out:
1181 	if (ret)
1182 		wc->w_target_locked = false;
1183 	return ret;
1184 }
1185 
1186 /*
1187  * Prepare a single cluster for write one cluster into the file.
1188  */
1189 static int ocfs2_write_cluster(struct address_space *mapping,
1190 			       u32 phys, unsigned int unwritten,
1191 			       unsigned int should_zero,
1192 			       struct ocfs2_alloc_context *data_ac,
1193 			       struct ocfs2_alloc_context *meta_ac,
1194 			       struct ocfs2_write_ctxt *wc, u32 cpos,
1195 			       loff_t user_pos, unsigned user_len)
1196 {
1197 	int ret, i, new;
1198 	u64 v_blkno, p_blkno;
1199 	struct inode *inode = mapping->host;
1200 	struct ocfs2_extent_tree et;
1201 
1202 	new = phys == 0 ? 1 : 0;
1203 	if (new) {
1204 		u32 tmp_pos;
1205 
1206 		/*
1207 		 * This is safe to call with the page locks - it won't take
1208 		 * any additional semaphores or cluster locks.
1209 		 */
1210 		tmp_pos = cpos;
1211 		ret = ocfs2_add_inode_data(OCFS2_SB(inode->i_sb), inode,
1212 					   &tmp_pos, 1, 0, wc->w_di_bh,
1213 					   wc->w_handle, data_ac,
1214 					   meta_ac, NULL);
1215 		/*
1216 		 * This shouldn't happen because we must have already
1217 		 * calculated the correct meta data allocation required. The
1218 		 * internal tree allocation code should know how to increase
1219 		 * transaction credits itself.
1220 		 *
1221 		 * If need be, we could handle -EAGAIN for a
1222 		 * RESTART_TRANS here.
1223 		 */
1224 		mlog_bug_on_msg(ret == -EAGAIN,
1225 				"Inode %llu: EAGAIN return during allocation.\n",
1226 				(unsigned long long)OCFS2_I(inode)->ip_blkno);
1227 		if (ret < 0) {
1228 			mlog_errno(ret);
1229 			goto out;
1230 		}
1231 	} else if (unwritten) {
1232 		ocfs2_init_dinode_extent_tree(&et, INODE_CACHE(inode),
1233 					      wc->w_di_bh);
1234 		ret = ocfs2_mark_extent_written(inode, &et,
1235 						wc->w_handle, cpos, 1, phys,
1236 						meta_ac, &wc->w_dealloc);
1237 		if (ret < 0) {
1238 			mlog_errno(ret);
1239 			goto out;
1240 		}
1241 	}
1242 
1243 	if (should_zero)
1244 		v_blkno = ocfs2_clusters_to_blocks(inode->i_sb, cpos);
1245 	else
1246 		v_blkno = user_pos >> inode->i_sb->s_blocksize_bits;
1247 
1248 	/*
1249 	 * The only reason this should fail is due to an inability to
1250 	 * find the extent added.
1251 	 */
1252 	ret = ocfs2_extent_map_get_blocks(inode, v_blkno, &p_blkno, NULL,
1253 					  NULL);
1254 	if (ret < 0) {
1255 		ocfs2_error(inode->i_sb, "Corrupting extend for inode %llu, "
1256 			    "at logical block %llu",
1257 			    (unsigned long long)OCFS2_I(inode)->ip_blkno,
1258 			    (unsigned long long)v_blkno);
1259 		goto out;
1260 	}
1261 
1262 	BUG_ON(p_blkno == 0);
1263 
1264 	for(i = 0; i < wc->w_num_pages; i++) {
1265 		int tmpret;
1266 
1267 		tmpret = ocfs2_prepare_page_for_write(inode, &p_blkno, wc,
1268 						      wc->w_pages[i], cpos,
1269 						      user_pos, user_len,
1270 						      should_zero);
1271 		if (tmpret) {
1272 			mlog_errno(tmpret);
1273 			if (ret == 0)
1274 				ret = tmpret;
1275 		}
1276 	}
1277 
1278 	/*
1279 	 * We only have cleanup to do in case of allocating write.
1280 	 */
1281 	if (ret && new)
1282 		ocfs2_write_failure(inode, wc, user_pos, user_len);
1283 
1284 out:
1285 
1286 	return ret;
1287 }
1288 
1289 static int ocfs2_write_cluster_by_desc(struct address_space *mapping,
1290 				       struct ocfs2_alloc_context *data_ac,
1291 				       struct ocfs2_alloc_context *meta_ac,
1292 				       struct ocfs2_write_ctxt *wc,
1293 				       loff_t pos, unsigned len)
1294 {
1295 	int ret, i;
1296 	loff_t cluster_off;
1297 	unsigned int local_len = len;
1298 	struct ocfs2_write_cluster_desc *desc;
1299 	struct ocfs2_super *osb = OCFS2_SB(mapping->host->i_sb);
1300 
1301 	for (i = 0; i < wc->w_clen; i++) {
1302 		desc = &wc->w_desc[i];
1303 
1304 		/*
1305 		 * We have to make sure that the total write passed in
1306 		 * doesn't extend past a single cluster.
1307 		 */
1308 		local_len = len;
1309 		cluster_off = pos & (osb->s_clustersize - 1);
1310 		if ((cluster_off + local_len) > osb->s_clustersize)
1311 			local_len = osb->s_clustersize - cluster_off;
1312 
1313 		ret = ocfs2_write_cluster(mapping, desc->c_phys,
1314 					  desc->c_unwritten,
1315 					  desc->c_needs_zero,
1316 					  data_ac, meta_ac,
1317 					  wc, desc->c_cpos, pos, local_len);
1318 		if (ret) {
1319 			mlog_errno(ret);
1320 			goto out;
1321 		}
1322 
1323 		len -= local_len;
1324 		pos += local_len;
1325 	}
1326 
1327 	ret = 0;
1328 out:
1329 	return ret;
1330 }
1331 
1332 /*
1333  * ocfs2_write_end() wants to know which parts of the target page it
1334  * should complete the write on. It's easiest to compute them ahead of
1335  * time when a more complete view of the write is available.
1336  */
1337 static void ocfs2_set_target_boundaries(struct ocfs2_super *osb,
1338 					struct ocfs2_write_ctxt *wc,
1339 					loff_t pos, unsigned len, int alloc)
1340 {
1341 	struct ocfs2_write_cluster_desc *desc;
1342 
1343 	wc->w_target_from = pos & (PAGE_CACHE_SIZE - 1);
1344 	wc->w_target_to = wc->w_target_from + len;
1345 
1346 	if (alloc == 0)
1347 		return;
1348 
1349 	/*
1350 	 * Allocating write - we may have different boundaries based
1351 	 * on page size and cluster size.
1352 	 *
1353 	 * NOTE: We can no longer compute one value from the other as
1354 	 * the actual write length and user provided length may be
1355 	 * different.
1356 	 */
1357 
1358 	if (wc->w_large_pages) {
1359 		/*
1360 		 * We only care about the 1st and last cluster within
1361 		 * our range and whether they should be zero'd or not. Either
1362 		 * value may be extended out to the start/end of a
1363 		 * newly allocated cluster.
1364 		 */
1365 		desc = &wc->w_desc[0];
1366 		if (desc->c_needs_zero)
1367 			ocfs2_figure_cluster_boundaries(osb,
1368 							desc->c_cpos,
1369 							&wc->w_target_from,
1370 							NULL);
1371 
1372 		desc = &wc->w_desc[wc->w_clen - 1];
1373 		if (desc->c_needs_zero)
1374 			ocfs2_figure_cluster_boundaries(osb,
1375 							desc->c_cpos,
1376 							NULL,
1377 							&wc->w_target_to);
1378 	} else {
1379 		wc->w_target_from = 0;
1380 		wc->w_target_to = PAGE_CACHE_SIZE;
1381 	}
1382 }
1383 
1384 /*
1385  * Populate each single-cluster write descriptor in the write context
1386  * with information about the i/o to be done.
1387  *
1388  * Returns the number of clusters that will have to be allocated, as
1389  * well as a worst case estimate of the number of extent records that
1390  * would have to be created during a write to an unwritten region.
1391  */
1392 static int ocfs2_populate_write_desc(struct inode *inode,
1393 				     struct ocfs2_write_ctxt *wc,
1394 				     unsigned int *clusters_to_alloc,
1395 				     unsigned int *extents_to_split)
1396 {
1397 	int ret;
1398 	struct ocfs2_write_cluster_desc *desc;
1399 	unsigned int num_clusters = 0;
1400 	unsigned int ext_flags = 0;
1401 	u32 phys = 0;
1402 	int i;
1403 
1404 	*clusters_to_alloc = 0;
1405 	*extents_to_split = 0;
1406 
1407 	for (i = 0; i < wc->w_clen; i++) {
1408 		desc = &wc->w_desc[i];
1409 		desc->c_cpos = wc->w_cpos + i;
1410 
1411 		if (num_clusters == 0) {
1412 			/*
1413 			 * Need to look up the next extent record.
1414 			 */
1415 			ret = ocfs2_get_clusters(inode, desc->c_cpos, &phys,
1416 						 &num_clusters, &ext_flags);
1417 			if (ret) {
1418 				mlog_errno(ret);
1419 				goto out;
1420 			}
1421 
1422 			/* We should already CoW the refcountd extent. */
1423 			BUG_ON(ext_flags & OCFS2_EXT_REFCOUNTED);
1424 
1425 			/*
1426 			 * Assume worst case - that we're writing in
1427 			 * the middle of the extent.
1428 			 *
1429 			 * We can assume that the write proceeds from
1430 			 * left to right, in which case the extent
1431 			 * insert code is smart enough to coalesce the
1432 			 * next splits into the previous records created.
1433 			 */
1434 			if (ext_flags & OCFS2_EXT_UNWRITTEN)
1435 				*extents_to_split = *extents_to_split + 2;
1436 		} else if (phys) {
1437 			/*
1438 			 * Only increment phys if it doesn't describe
1439 			 * a hole.
1440 			 */
1441 			phys++;
1442 		}
1443 
1444 		/*
1445 		 * If w_first_new_cpos is < UINT_MAX, we have a non-sparse
1446 		 * file that got extended.  w_first_new_cpos tells us
1447 		 * where the newly allocated clusters are so we can
1448 		 * zero them.
1449 		 */
1450 		if (desc->c_cpos >= wc->w_first_new_cpos) {
1451 			BUG_ON(phys == 0);
1452 			desc->c_needs_zero = 1;
1453 		}
1454 
1455 		desc->c_phys = phys;
1456 		if (phys == 0) {
1457 			desc->c_new = 1;
1458 			desc->c_needs_zero = 1;
1459 			*clusters_to_alloc = *clusters_to_alloc + 1;
1460 		}
1461 
1462 		if (ext_flags & OCFS2_EXT_UNWRITTEN) {
1463 			desc->c_unwritten = 1;
1464 			desc->c_needs_zero = 1;
1465 		}
1466 
1467 		num_clusters--;
1468 	}
1469 
1470 	ret = 0;
1471 out:
1472 	return ret;
1473 }
1474 
1475 static int ocfs2_write_begin_inline(struct address_space *mapping,
1476 				    struct inode *inode,
1477 				    struct ocfs2_write_ctxt *wc)
1478 {
1479 	int ret;
1480 	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
1481 	struct page *page;
1482 	handle_t *handle;
1483 	struct ocfs2_dinode *di = (struct ocfs2_dinode *)wc->w_di_bh->b_data;
1484 
1485 	page = find_or_create_page(mapping, 0, GFP_NOFS);
1486 	if (!page) {
1487 		ret = -ENOMEM;
1488 		mlog_errno(ret);
1489 		goto out;
1490 	}
1491 	/*
1492 	 * If we don't set w_num_pages then this page won't get unlocked
1493 	 * and freed on cleanup of the write context.
1494 	 */
1495 	wc->w_pages[0] = wc->w_target_page = page;
1496 	wc->w_num_pages = 1;
1497 
1498 	handle = ocfs2_start_trans(osb, OCFS2_INODE_UPDATE_CREDITS);
1499 	if (IS_ERR(handle)) {
1500 		ret = PTR_ERR(handle);
1501 		mlog_errno(ret);
1502 		goto out;
1503 	}
1504 
1505 	ret = ocfs2_journal_access_di(handle, INODE_CACHE(inode), wc->w_di_bh,
1506 				      OCFS2_JOURNAL_ACCESS_WRITE);
1507 	if (ret) {
1508 		ocfs2_commit_trans(osb, handle);
1509 
1510 		mlog_errno(ret);
1511 		goto out;
1512 	}
1513 
1514 	if (!(OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL))
1515 		ocfs2_set_inode_data_inline(inode, di);
1516 
1517 	if (!PageUptodate(page)) {
1518 		ret = ocfs2_read_inline_data(inode, page, wc->w_di_bh);
1519 		if (ret) {
1520 			ocfs2_commit_trans(osb, handle);
1521 
1522 			goto out;
1523 		}
1524 	}
1525 
1526 	wc->w_handle = handle;
1527 out:
1528 	return ret;
1529 }
1530 
1531 int ocfs2_size_fits_inline_data(struct buffer_head *di_bh, u64 new_size)
1532 {
1533 	struct ocfs2_dinode *di = (struct ocfs2_dinode *)di_bh->b_data;
1534 
1535 	if (new_size <= le16_to_cpu(di->id2.i_data.id_count))
1536 		return 1;
1537 	return 0;
1538 }
1539 
1540 static int ocfs2_try_to_write_inline_data(struct address_space *mapping,
1541 					  struct inode *inode, loff_t pos,
1542 					  unsigned len, struct page *mmap_page,
1543 					  struct ocfs2_write_ctxt *wc)
1544 {
1545 	int ret, written = 0;
1546 	loff_t end = pos + len;
1547 	struct ocfs2_inode_info *oi = OCFS2_I(inode);
1548 	struct ocfs2_dinode *di = NULL;
1549 
1550 	trace_ocfs2_try_to_write_inline_data((unsigned long long)oi->ip_blkno,
1551 					     len, (unsigned long long)pos,
1552 					     oi->ip_dyn_features);
1553 
1554 	/*
1555 	 * Handle inodes which already have inline data 1st.
1556 	 */
1557 	if (oi->ip_dyn_features & OCFS2_INLINE_DATA_FL) {
1558 		if (mmap_page == NULL &&
1559 		    ocfs2_size_fits_inline_data(wc->w_di_bh, end))
1560 			goto do_inline_write;
1561 
1562 		/*
1563 		 * The write won't fit - we have to give this inode an
1564 		 * inline extent list now.
1565 		 */
1566 		ret = ocfs2_convert_inline_data_to_extents(inode, wc->w_di_bh);
1567 		if (ret)
1568 			mlog_errno(ret);
1569 		goto out;
1570 	}
1571 
1572 	/*
1573 	 * Check whether the inode can accept inline data.
1574 	 */
1575 	if (oi->ip_clusters != 0 || i_size_read(inode) != 0)
1576 		return 0;
1577 
1578 	/*
1579 	 * Check whether the write can fit.
1580 	 */
1581 	di = (struct ocfs2_dinode *)wc->w_di_bh->b_data;
1582 	if (mmap_page ||
1583 	    end > ocfs2_max_inline_data_with_xattr(inode->i_sb, di))
1584 		return 0;
1585 
1586 do_inline_write:
1587 	ret = ocfs2_write_begin_inline(mapping, inode, wc);
1588 	if (ret) {
1589 		mlog_errno(ret);
1590 		goto out;
1591 	}
1592 
1593 	/*
1594 	 * This signals to the caller that the data can be written
1595 	 * inline.
1596 	 */
1597 	written = 1;
1598 out:
1599 	return written ? written : ret;
1600 }
1601 
1602 /*
1603  * This function only does anything for file systems which can't
1604  * handle sparse files.
1605  *
1606  * What we want to do here is fill in any hole between the current end
1607  * of allocation and the end of our write. That way the rest of the
1608  * write path can treat it as an non-allocating write, which has no
1609  * special case code for sparse/nonsparse files.
1610  */
1611 static int ocfs2_expand_nonsparse_inode(struct inode *inode,
1612 					struct buffer_head *di_bh,
1613 					loff_t pos, unsigned len,
1614 					struct ocfs2_write_ctxt *wc)
1615 {
1616 	int ret;
1617 	loff_t newsize = pos + len;
1618 
1619 	BUG_ON(ocfs2_sparse_alloc(OCFS2_SB(inode->i_sb)));
1620 
1621 	if (newsize <= i_size_read(inode))
1622 		return 0;
1623 
1624 	ret = ocfs2_extend_no_holes(inode, di_bh, newsize, pos);
1625 	if (ret)
1626 		mlog_errno(ret);
1627 
1628 	wc->w_first_new_cpos =
1629 		ocfs2_clusters_for_bytes(inode->i_sb, i_size_read(inode));
1630 
1631 	return ret;
1632 }
1633 
1634 static int ocfs2_zero_tail(struct inode *inode, struct buffer_head *di_bh,
1635 			   loff_t pos)
1636 {
1637 	int ret = 0;
1638 
1639 	BUG_ON(!ocfs2_sparse_alloc(OCFS2_SB(inode->i_sb)));
1640 	if (pos > i_size_read(inode))
1641 		ret = ocfs2_zero_extend(inode, di_bh, pos);
1642 
1643 	return ret;
1644 }
1645 
1646 /*
1647  * Try to flush truncate logs if we can free enough clusters from it.
1648  * As for return value, "< 0" means error, "0" no space and "1" means
1649  * we have freed enough spaces and let the caller try to allocate again.
1650  */
1651 static int ocfs2_try_to_free_truncate_log(struct ocfs2_super *osb,
1652 					  unsigned int needed)
1653 {
1654 	tid_t target;
1655 	int ret = 0;
1656 	unsigned int truncated_clusters;
1657 
1658 	mutex_lock(&osb->osb_tl_inode->i_mutex);
1659 	truncated_clusters = osb->truncated_clusters;
1660 	mutex_unlock(&osb->osb_tl_inode->i_mutex);
1661 
1662 	/*
1663 	 * Check whether we can succeed in allocating if we free
1664 	 * the truncate log.
1665 	 */
1666 	if (truncated_clusters < needed)
1667 		goto out;
1668 
1669 	ret = ocfs2_flush_truncate_log(osb);
1670 	if (ret) {
1671 		mlog_errno(ret);
1672 		goto out;
1673 	}
1674 
1675 	if (jbd2_journal_start_commit(osb->journal->j_journal, &target)) {
1676 		jbd2_log_wait_commit(osb->journal->j_journal, target);
1677 		ret = 1;
1678 	}
1679 out:
1680 	return ret;
1681 }
1682 
1683 int ocfs2_write_begin_nolock(struct file *filp,
1684 			     struct address_space *mapping,
1685 			     loff_t pos, unsigned len, unsigned flags,
1686 			     struct page **pagep, void **fsdata,
1687 			     struct buffer_head *di_bh, struct page *mmap_page)
1688 {
1689 	int ret, cluster_of_pages, credits = OCFS2_INODE_UPDATE_CREDITS;
1690 	unsigned int clusters_to_alloc, extents_to_split, clusters_need = 0;
1691 	struct ocfs2_write_ctxt *wc;
1692 	struct inode *inode = mapping->host;
1693 	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
1694 	struct ocfs2_dinode *di;
1695 	struct ocfs2_alloc_context *data_ac = NULL;
1696 	struct ocfs2_alloc_context *meta_ac = NULL;
1697 	handle_t *handle;
1698 	struct ocfs2_extent_tree et;
1699 	int try_free = 1, ret1;
1700 
1701 try_again:
1702 	ret = ocfs2_alloc_write_ctxt(&wc, osb, pos, len, di_bh);
1703 	if (ret) {
1704 		mlog_errno(ret);
1705 		return ret;
1706 	}
1707 
1708 	if (ocfs2_supports_inline_data(osb)) {
1709 		ret = ocfs2_try_to_write_inline_data(mapping, inode, pos, len,
1710 						     mmap_page, wc);
1711 		if (ret == 1) {
1712 			ret = 0;
1713 			goto success;
1714 		}
1715 		if (ret < 0) {
1716 			mlog_errno(ret);
1717 			goto out;
1718 		}
1719 	}
1720 
1721 	if (ocfs2_sparse_alloc(osb))
1722 		ret = ocfs2_zero_tail(inode, di_bh, pos);
1723 	else
1724 		ret = ocfs2_expand_nonsparse_inode(inode, di_bh, pos, len,
1725 						   wc);
1726 	if (ret) {
1727 		mlog_errno(ret);
1728 		goto out;
1729 	}
1730 
1731 	ret = ocfs2_check_range_for_refcount(inode, pos, len);
1732 	if (ret < 0) {
1733 		mlog_errno(ret);
1734 		goto out;
1735 	} else if (ret == 1) {
1736 		clusters_need = wc->w_clen;
1737 		ret = ocfs2_refcount_cow(inode, di_bh,
1738 					 wc->w_cpos, wc->w_clen, UINT_MAX);
1739 		if (ret) {
1740 			mlog_errno(ret);
1741 			goto out;
1742 		}
1743 	}
1744 
1745 	ret = ocfs2_populate_write_desc(inode, wc, &clusters_to_alloc,
1746 					&extents_to_split);
1747 	if (ret) {
1748 		mlog_errno(ret);
1749 		goto out;
1750 	}
1751 	clusters_need += clusters_to_alloc;
1752 
1753 	di = (struct ocfs2_dinode *)wc->w_di_bh->b_data;
1754 
1755 	trace_ocfs2_write_begin_nolock(
1756 			(unsigned long long)OCFS2_I(inode)->ip_blkno,
1757 			(long long)i_size_read(inode),
1758 			le32_to_cpu(di->i_clusters),
1759 			pos, len, flags, mmap_page,
1760 			clusters_to_alloc, extents_to_split);
1761 
1762 	/*
1763 	 * We set w_target_from, w_target_to here so that
1764 	 * ocfs2_write_end() knows which range in the target page to
1765 	 * write out. An allocation requires that we write the entire
1766 	 * cluster range.
1767 	 */
1768 	if (clusters_to_alloc || extents_to_split) {
1769 		/*
1770 		 * XXX: We are stretching the limits of
1771 		 * ocfs2_lock_allocators(). It greatly over-estimates
1772 		 * the work to be done.
1773 		 */
1774 		ocfs2_init_dinode_extent_tree(&et, INODE_CACHE(inode),
1775 					      wc->w_di_bh);
1776 		ret = ocfs2_lock_allocators(inode, &et,
1777 					    clusters_to_alloc, extents_to_split,
1778 					    &data_ac, &meta_ac);
1779 		if (ret) {
1780 			mlog_errno(ret);
1781 			goto out;
1782 		}
1783 
1784 		if (data_ac)
1785 			data_ac->ac_resv = &OCFS2_I(inode)->ip_la_data_resv;
1786 
1787 		credits = ocfs2_calc_extend_credits(inode->i_sb,
1788 						    &di->id2.i_list);
1789 
1790 	}
1791 
1792 	/*
1793 	 * We have to zero sparse allocated clusters, unwritten extent clusters,
1794 	 * and non-sparse clusters we just extended.  For non-sparse writes,
1795 	 * we know zeros will only be needed in the first and/or last cluster.
1796 	 */
1797 	if (clusters_to_alloc || extents_to_split ||
1798 	    (wc->w_clen && (wc->w_desc[0].c_needs_zero ||
1799 			    wc->w_desc[wc->w_clen - 1].c_needs_zero)))
1800 		cluster_of_pages = 1;
1801 	else
1802 		cluster_of_pages = 0;
1803 
1804 	ocfs2_set_target_boundaries(osb, wc, pos, len, cluster_of_pages);
1805 
1806 	handle = ocfs2_start_trans(osb, credits);
1807 	if (IS_ERR(handle)) {
1808 		ret = PTR_ERR(handle);
1809 		mlog_errno(ret);
1810 		goto out;
1811 	}
1812 
1813 	wc->w_handle = handle;
1814 
1815 	if (clusters_to_alloc) {
1816 		ret = dquot_alloc_space_nodirty(inode,
1817 			ocfs2_clusters_to_bytes(osb->sb, clusters_to_alloc));
1818 		if (ret)
1819 			goto out_commit;
1820 	}
1821 	/*
1822 	 * We don't want this to fail in ocfs2_write_end(), so do it
1823 	 * here.
1824 	 */
1825 	ret = ocfs2_journal_access_di(handle, INODE_CACHE(inode), wc->w_di_bh,
1826 				      OCFS2_JOURNAL_ACCESS_WRITE);
1827 	if (ret) {
1828 		mlog_errno(ret);
1829 		goto out_quota;
1830 	}
1831 
1832 	/*
1833 	 * Fill our page array first. That way we've grabbed enough so
1834 	 * that we can zero and flush if we error after adding the
1835 	 * extent.
1836 	 */
1837 	ret = ocfs2_grab_pages_for_write(mapping, wc, wc->w_cpos, pos, len,
1838 					 cluster_of_pages, mmap_page);
1839 	if (ret && ret != -EAGAIN) {
1840 		mlog_errno(ret);
1841 		goto out_quota;
1842 	}
1843 
1844 	/*
1845 	 * ocfs2_grab_pages_for_write() returns -EAGAIN if it could not lock
1846 	 * the target page. In this case, we exit with no error and no target
1847 	 * page. This will trigger the caller, page_mkwrite(), to re-try
1848 	 * the operation.
1849 	 */
1850 	if (ret == -EAGAIN) {
1851 		BUG_ON(wc->w_target_page);
1852 		ret = 0;
1853 		goto out_quota;
1854 	}
1855 
1856 	ret = ocfs2_write_cluster_by_desc(mapping, data_ac, meta_ac, wc, pos,
1857 					  len);
1858 	if (ret) {
1859 		mlog_errno(ret);
1860 		goto out_quota;
1861 	}
1862 
1863 	if (data_ac)
1864 		ocfs2_free_alloc_context(data_ac);
1865 	if (meta_ac)
1866 		ocfs2_free_alloc_context(meta_ac);
1867 
1868 success:
1869 	*pagep = wc->w_target_page;
1870 	*fsdata = wc;
1871 	return 0;
1872 out_quota:
1873 	if (clusters_to_alloc)
1874 		dquot_free_space(inode,
1875 			  ocfs2_clusters_to_bytes(osb->sb, clusters_to_alloc));
1876 out_commit:
1877 	ocfs2_commit_trans(osb, handle);
1878 
1879 out:
1880 	ocfs2_free_write_ctxt(wc);
1881 
1882 	if (data_ac) {
1883 		ocfs2_free_alloc_context(data_ac);
1884 		data_ac = NULL;
1885 	}
1886 	if (meta_ac) {
1887 		ocfs2_free_alloc_context(meta_ac);
1888 		meta_ac = NULL;
1889 	}
1890 
1891 	if (ret == -ENOSPC && try_free) {
1892 		/*
1893 		 * Try to free some truncate log so that we can have enough
1894 		 * clusters to allocate.
1895 		 */
1896 		try_free = 0;
1897 
1898 		ret1 = ocfs2_try_to_free_truncate_log(osb, clusters_need);
1899 		if (ret1 == 1)
1900 			goto try_again;
1901 
1902 		if (ret1 < 0)
1903 			mlog_errno(ret1);
1904 	}
1905 
1906 	return ret;
1907 }
1908 
1909 static int ocfs2_write_begin(struct file *file, struct address_space *mapping,
1910 			     loff_t pos, unsigned len, unsigned flags,
1911 			     struct page **pagep, void **fsdata)
1912 {
1913 	int ret;
1914 	struct buffer_head *di_bh = NULL;
1915 	struct inode *inode = mapping->host;
1916 
1917 	ret = ocfs2_inode_lock(inode, &di_bh, 1);
1918 	if (ret) {
1919 		mlog_errno(ret);
1920 		return ret;
1921 	}
1922 
1923 	/*
1924 	 * Take alloc sem here to prevent concurrent lookups. That way
1925 	 * the mapping, zeroing and tree manipulation within
1926 	 * ocfs2_write() will be safe against ->readpage(). This
1927 	 * should also serve to lock out allocation from a shared
1928 	 * writeable region.
1929 	 */
1930 	down_write(&OCFS2_I(inode)->ip_alloc_sem);
1931 
1932 	ret = ocfs2_write_begin_nolock(file, mapping, pos, len, flags, pagep,
1933 				       fsdata, di_bh, NULL);
1934 	if (ret) {
1935 		mlog_errno(ret);
1936 		goto out_fail;
1937 	}
1938 
1939 	brelse(di_bh);
1940 
1941 	return 0;
1942 
1943 out_fail:
1944 	up_write(&OCFS2_I(inode)->ip_alloc_sem);
1945 
1946 	brelse(di_bh);
1947 	ocfs2_inode_unlock(inode, 1);
1948 
1949 	return ret;
1950 }
1951 
1952 static void ocfs2_write_end_inline(struct inode *inode, loff_t pos,
1953 				   unsigned len, unsigned *copied,
1954 				   struct ocfs2_dinode *di,
1955 				   struct ocfs2_write_ctxt *wc)
1956 {
1957 	void *kaddr;
1958 
1959 	if (unlikely(*copied < len)) {
1960 		if (!PageUptodate(wc->w_target_page)) {
1961 			*copied = 0;
1962 			return;
1963 		}
1964 	}
1965 
1966 	kaddr = kmap_atomic(wc->w_target_page);
1967 	memcpy(di->id2.i_data.id_data + pos, kaddr + pos, *copied);
1968 	kunmap_atomic(kaddr);
1969 
1970 	trace_ocfs2_write_end_inline(
1971 	     (unsigned long long)OCFS2_I(inode)->ip_blkno,
1972 	     (unsigned long long)pos, *copied,
1973 	     le16_to_cpu(di->id2.i_data.id_count),
1974 	     le16_to_cpu(di->i_dyn_features));
1975 }
1976 
1977 int ocfs2_write_end_nolock(struct address_space *mapping,
1978 			   loff_t pos, unsigned len, unsigned copied,
1979 			   struct page *page, void *fsdata)
1980 {
1981 	int i;
1982 	unsigned from, to, start = pos & (PAGE_CACHE_SIZE - 1);
1983 	struct inode *inode = mapping->host;
1984 	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
1985 	struct ocfs2_write_ctxt *wc = fsdata;
1986 	struct ocfs2_dinode *di = (struct ocfs2_dinode *)wc->w_di_bh->b_data;
1987 	handle_t *handle = wc->w_handle;
1988 	struct page *tmppage;
1989 
1990 	if (OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL) {
1991 		ocfs2_write_end_inline(inode, pos, len, &copied, di, wc);
1992 		goto out_write_size;
1993 	}
1994 
1995 	if (unlikely(copied < len)) {
1996 		if (!PageUptodate(wc->w_target_page))
1997 			copied = 0;
1998 
1999 		ocfs2_zero_new_buffers(wc->w_target_page, start+copied,
2000 				       start+len);
2001 	}
2002 	flush_dcache_page(wc->w_target_page);
2003 
2004 	for(i = 0; i < wc->w_num_pages; i++) {
2005 		tmppage = wc->w_pages[i];
2006 
2007 		if (tmppage == wc->w_target_page) {
2008 			from = wc->w_target_from;
2009 			to = wc->w_target_to;
2010 
2011 			BUG_ON(from > PAGE_CACHE_SIZE ||
2012 			       to > PAGE_CACHE_SIZE ||
2013 			       to < from);
2014 		} else {
2015 			/*
2016 			 * Pages adjacent to the target (if any) imply
2017 			 * a hole-filling write in which case we want
2018 			 * to flush their entire range.
2019 			 */
2020 			from = 0;
2021 			to = PAGE_CACHE_SIZE;
2022 		}
2023 
2024 		if (page_has_buffers(tmppage)) {
2025 			if (ocfs2_should_order_data(inode))
2026 				ocfs2_jbd2_file_inode(wc->w_handle, inode);
2027 			block_commit_write(tmppage, from, to);
2028 		}
2029 	}
2030 
2031 out_write_size:
2032 	pos += copied;
2033 	if (pos > i_size_read(inode)) {
2034 		i_size_write(inode, pos);
2035 		mark_inode_dirty(inode);
2036 	}
2037 	inode->i_blocks = ocfs2_inode_sector_count(inode);
2038 	di->i_size = cpu_to_le64((u64)i_size_read(inode));
2039 	inode->i_mtime = inode->i_ctime = CURRENT_TIME;
2040 	di->i_mtime = di->i_ctime = cpu_to_le64(inode->i_mtime.tv_sec);
2041 	di->i_mtime_nsec = di->i_ctime_nsec = cpu_to_le32(inode->i_mtime.tv_nsec);
2042 	ocfs2_update_inode_fsync_trans(handle, inode, 1);
2043 	ocfs2_journal_dirty(handle, wc->w_di_bh);
2044 
2045 	ocfs2_commit_trans(osb, handle);
2046 
2047 	ocfs2_run_deallocs(osb, &wc->w_dealloc);
2048 
2049 	ocfs2_free_write_ctxt(wc);
2050 
2051 	return copied;
2052 }
2053 
2054 static int ocfs2_write_end(struct file *file, struct address_space *mapping,
2055 			   loff_t pos, unsigned len, unsigned copied,
2056 			   struct page *page, void *fsdata)
2057 {
2058 	int ret;
2059 	struct inode *inode = mapping->host;
2060 
2061 	ret = ocfs2_write_end_nolock(mapping, pos, len, copied, page, fsdata);
2062 
2063 	up_write(&OCFS2_I(inode)->ip_alloc_sem);
2064 	ocfs2_inode_unlock(inode, 1);
2065 
2066 	return ret;
2067 }
2068 
2069 const struct address_space_operations ocfs2_aops = {
2070 	.readpage		= ocfs2_readpage,
2071 	.readpages		= ocfs2_readpages,
2072 	.writepage		= ocfs2_writepage,
2073 	.write_begin		= ocfs2_write_begin,
2074 	.write_end		= ocfs2_write_end,
2075 	.bmap			= ocfs2_bmap,
2076 	.direct_IO		= ocfs2_direct_IO,
2077 	.invalidatepage		= block_invalidatepage,
2078 	.releasepage		= ocfs2_releasepage,
2079 	.migratepage		= buffer_migrate_page,
2080 	.is_partially_uptodate	= block_is_partially_uptodate,
2081 	.error_remove_page	= generic_error_remove_page,
2082 };
2083