xref: /openbmc/linux/fs/ocfs2/aops.c (revision 278d3ba6)
1  // SPDX-License-Identifier: GPL-2.0-or-later
2  /*
3   * Copyright (C) 2002, 2004 Oracle.  All rights reserved.
4   */
5  
6  #include <linux/fs.h>
7  #include <linux/slab.h>
8  #include <linux/highmem.h>
9  #include <linux/pagemap.h>
10  #include <asm/byteorder.h>
11  #include <linux/swap.h>
12  #include <linux/mpage.h>
13  #include <linux/quotaops.h>
14  #include <linux/blkdev.h>
15  #include <linux/uio.h>
16  #include <linux/mm.h>
17  
18  #include <cluster/masklog.h>
19  
20  #include "ocfs2.h"
21  
22  #include "alloc.h"
23  #include "aops.h"
24  #include "dlmglue.h"
25  #include "extent_map.h"
26  #include "file.h"
27  #include "inode.h"
28  #include "journal.h"
29  #include "suballoc.h"
30  #include "super.h"
31  #include "symlink.h"
32  #include "refcounttree.h"
33  #include "ocfs2_trace.h"
34  
35  #include "buffer_head_io.h"
36  #include "dir.h"
37  #include "namei.h"
38  #include "sysfile.h"
39  
40  static int ocfs2_symlink_get_block(struct inode *inode, sector_t iblock,
41  				   struct buffer_head *bh_result, int create)
42  {
43  	int err = -EIO;
44  	int status;
45  	struct ocfs2_dinode *fe = NULL;
46  	struct buffer_head *bh = NULL;
47  	struct buffer_head *buffer_cache_bh = NULL;
48  	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
49  	void *kaddr;
50  
51  	trace_ocfs2_symlink_get_block(
52  			(unsigned long long)OCFS2_I(inode)->ip_blkno,
53  			(unsigned long long)iblock, bh_result, create);
54  
55  	BUG_ON(ocfs2_inode_is_fast_symlink(inode));
56  
57  	if ((iblock << inode->i_sb->s_blocksize_bits) > PATH_MAX + 1) {
58  		mlog(ML_ERROR, "block offset > PATH_MAX: %llu",
59  		     (unsigned long long)iblock);
60  		goto bail;
61  	}
62  
63  	status = ocfs2_read_inode_block(inode, &bh);
64  	if (status < 0) {
65  		mlog_errno(status);
66  		goto bail;
67  	}
68  	fe = (struct ocfs2_dinode *) bh->b_data;
69  
70  	if ((u64)iblock >= ocfs2_clusters_to_blocks(inode->i_sb,
71  						    le32_to_cpu(fe->i_clusters))) {
72  		err = -ENOMEM;
73  		mlog(ML_ERROR, "block offset is outside the allocated size: "
74  		     "%llu\n", (unsigned long long)iblock);
75  		goto bail;
76  	}
77  
78  	/* We don't use the page cache to create symlink data, so if
79  	 * need be, copy it over from the buffer cache. */
80  	if (!buffer_uptodate(bh_result) && ocfs2_inode_is_new(inode)) {
81  		u64 blkno = le64_to_cpu(fe->id2.i_list.l_recs[0].e_blkno) +
82  			    iblock;
83  		buffer_cache_bh = sb_getblk(osb->sb, blkno);
84  		if (!buffer_cache_bh) {
85  			err = -ENOMEM;
86  			mlog(ML_ERROR, "couldn't getblock for symlink!\n");
87  			goto bail;
88  		}
89  
90  		/* we haven't locked out transactions, so a commit
91  		 * could've happened. Since we've got a reference on
92  		 * the bh, even if it commits while we're doing the
93  		 * copy, the data is still good. */
94  		if (buffer_jbd(buffer_cache_bh)
95  		    && ocfs2_inode_is_new(inode)) {
96  			kaddr = kmap_atomic(bh_result->b_page);
97  			if (!kaddr) {
98  				mlog(ML_ERROR, "couldn't kmap!\n");
99  				goto bail;
100  			}
101  			memcpy(kaddr + (bh_result->b_size * iblock),
102  			       buffer_cache_bh->b_data,
103  			       bh_result->b_size);
104  			kunmap_atomic(kaddr);
105  			set_buffer_uptodate(bh_result);
106  		}
107  		brelse(buffer_cache_bh);
108  	}
109  
110  	map_bh(bh_result, inode->i_sb,
111  	       le64_to_cpu(fe->id2.i_list.l_recs[0].e_blkno) + iblock);
112  
113  	err = 0;
114  
115  bail:
116  	brelse(bh);
117  
118  	return err;
119  }
120  
121  static int ocfs2_lock_get_block(struct inode *inode, sector_t iblock,
122  		    struct buffer_head *bh_result, int create)
123  {
124  	int ret = 0;
125  	struct ocfs2_inode_info *oi = OCFS2_I(inode);
126  
127  	down_read(&oi->ip_alloc_sem);
128  	ret = ocfs2_get_block(inode, iblock, bh_result, create);
129  	up_read(&oi->ip_alloc_sem);
130  
131  	return ret;
132  }
133  
134  int ocfs2_get_block(struct inode *inode, sector_t iblock,
135  		    struct buffer_head *bh_result, int create)
136  {
137  	int err = 0;
138  	unsigned int ext_flags;
139  	u64 max_blocks = bh_result->b_size >> inode->i_blkbits;
140  	u64 p_blkno, count, past_eof;
141  	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
142  
143  	trace_ocfs2_get_block((unsigned long long)OCFS2_I(inode)->ip_blkno,
144  			      (unsigned long long)iblock, bh_result, create);
145  
146  	if (OCFS2_I(inode)->ip_flags & OCFS2_INODE_SYSTEM_FILE)
147  		mlog(ML_NOTICE, "get_block on system inode 0x%p (%lu)\n",
148  		     inode, inode->i_ino);
149  
150  	if (S_ISLNK(inode->i_mode)) {
151  		/* this always does I/O for some reason. */
152  		err = ocfs2_symlink_get_block(inode, iblock, bh_result, create);
153  		goto bail;
154  	}
155  
156  	err = ocfs2_extent_map_get_blocks(inode, iblock, &p_blkno, &count,
157  					  &ext_flags);
158  	if (err) {
159  		mlog(ML_ERROR, "Error %d from get_blocks(0x%p, %llu, 1, "
160  		     "%llu, NULL)\n", err, inode, (unsigned long long)iblock,
161  		     (unsigned long long)p_blkno);
162  		goto bail;
163  	}
164  
165  	if (max_blocks < count)
166  		count = max_blocks;
167  
168  	/*
169  	 * ocfs2 never allocates in this function - the only time we
170  	 * need to use BH_New is when we're extending i_size on a file
171  	 * system which doesn't support holes, in which case BH_New
172  	 * allows __block_write_begin() to zero.
173  	 *
174  	 * If we see this on a sparse file system, then a truncate has
175  	 * raced us and removed the cluster. In this case, we clear
176  	 * the buffers dirty and uptodate bits and let the buffer code
177  	 * ignore it as a hole.
178  	 */
179  	if (create && p_blkno == 0 && ocfs2_sparse_alloc(osb)) {
180  		clear_buffer_dirty(bh_result);
181  		clear_buffer_uptodate(bh_result);
182  		goto bail;
183  	}
184  
185  	/* Treat the unwritten extent as a hole for zeroing purposes. */
186  	if (p_blkno && !(ext_flags & OCFS2_EXT_UNWRITTEN))
187  		map_bh(bh_result, inode->i_sb, p_blkno);
188  
189  	bh_result->b_size = count << inode->i_blkbits;
190  
191  	if (!ocfs2_sparse_alloc(osb)) {
192  		if (p_blkno == 0) {
193  			err = -EIO;
194  			mlog(ML_ERROR,
195  			     "iblock = %llu p_blkno = %llu blkno=(%llu)\n",
196  			     (unsigned long long)iblock,
197  			     (unsigned long long)p_blkno,
198  			     (unsigned long long)OCFS2_I(inode)->ip_blkno);
199  			mlog(ML_ERROR, "Size %llu, clusters %u\n", (unsigned long long)i_size_read(inode), OCFS2_I(inode)->ip_clusters);
200  			dump_stack();
201  			goto bail;
202  		}
203  	}
204  
205  	past_eof = ocfs2_blocks_for_bytes(inode->i_sb, i_size_read(inode));
206  
207  	trace_ocfs2_get_block_end((unsigned long long)OCFS2_I(inode)->ip_blkno,
208  				  (unsigned long long)past_eof);
209  	if (create && (iblock >= past_eof))
210  		set_buffer_new(bh_result);
211  
212  bail:
213  	if (err < 0)
214  		err = -EIO;
215  
216  	return err;
217  }
218  
219  int ocfs2_read_inline_data(struct inode *inode, struct page *page,
220  			   struct buffer_head *di_bh)
221  {
222  	void *kaddr;
223  	loff_t size;
224  	struct ocfs2_dinode *di = (struct ocfs2_dinode *)di_bh->b_data;
225  
226  	if (!(le16_to_cpu(di->i_dyn_features) & OCFS2_INLINE_DATA_FL)) {
227  		ocfs2_error(inode->i_sb, "Inode %llu lost inline data flag\n",
228  			    (unsigned long long)OCFS2_I(inode)->ip_blkno);
229  		return -EROFS;
230  	}
231  
232  	size = i_size_read(inode);
233  
234  	if (size > PAGE_SIZE ||
235  	    size > ocfs2_max_inline_data_with_xattr(inode->i_sb, di)) {
236  		ocfs2_error(inode->i_sb,
237  			    "Inode %llu has with inline data has bad size: %Lu\n",
238  			    (unsigned long long)OCFS2_I(inode)->ip_blkno,
239  			    (unsigned long long)size);
240  		return -EROFS;
241  	}
242  
243  	kaddr = kmap_atomic(page);
244  	if (size)
245  		memcpy(kaddr, di->id2.i_data.id_data, size);
246  	/* Clear the remaining part of the page */
247  	memset(kaddr + size, 0, PAGE_SIZE - size);
248  	flush_dcache_page(page);
249  	kunmap_atomic(kaddr);
250  
251  	SetPageUptodate(page);
252  
253  	return 0;
254  }
255  
256  static int ocfs2_readpage_inline(struct inode *inode, struct page *page)
257  {
258  	int ret;
259  	struct buffer_head *di_bh = NULL;
260  
261  	BUG_ON(!PageLocked(page));
262  	BUG_ON(!(OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL));
263  
264  	ret = ocfs2_read_inode_block(inode, &di_bh);
265  	if (ret) {
266  		mlog_errno(ret);
267  		goto out;
268  	}
269  
270  	ret = ocfs2_read_inline_data(inode, page, di_bh);
271  out:
272  	unlock_page(page);
273  
274  	brelse(di_bh);
275  	return ret;
276  }
277  
278  static int ocfs2_read_folio(struct file *file, struct folio *folio)
279  {
280  	struct inode *inode = folio->mapping->host;
281  	struct ocfs2_inode_info *oi = OCFS2_I(inode);
282  	loff_t start = folio_pos(folio);
283  	int ret, unlock = 1;
284  
285  	trace_ocfs2_readpage((unsigned long long)oi->ip_blkno, folio->index);
286  
287  	ret = ocfs2_inode_lock_with_page(inode, NULL, 0, &folio->page);
288  	if (ret != 0) {
289  		if (ret == AOP_TRUNCATED_PAGE)
290  			unlock = 0;
291  		mlog_errno(ret);
292  		goto out;
293  	}
294  
295  	if (down_read_trylock(&oi->ip_alloc_sem) == 0) {
296  		/*
297  		 * Unlock the folio and cycle ip_alloc_sem so that we don't
298  		 * busyloop waiting for ip_alloc_sem to unlock
299  		 */
300  		ret = AOP_TRUNCATED_PAGE;
301  		folio_unlock(folio);
302  		unlock = 0;
303  		down_read(&oi->ip_alloc_sem);
304  		up_read(&oi->ip_alloc_sem);
305  		goto out_inode_unlock;
306  	}
307  
308  	/*
309  	 * i_size might have just been updated as we grabed the meta lock.  We
310  	 * might now be discovering a truncate that hit on another node.
311  	 * block_read_full_folio->get_block freaks out if it is asked to read
312  	 * beyond the end of a file, so we check here.  Callers
313  	 * (generic_file_read, vm_ops->fault) are clever enough to check i_size
314  	 * and notice that the folio they just read isn't needed.
315  	 *
316  	 * XXX sys_readahead() seems to get that wrong?
317  	 */
318  	if (start >= i_size_read(inode)) {
319  		folio_zero_segment(folio, 0, folio_size(folio));
320  		folio_mark_uptodate(folio);
321  		ret = 0;
322  		goto out_alloc;
323  	}
324  
325  	if (oi->ip_dyn_features & OCFS2_INLINE_DATA_FL)
326  		ret = ocfs2_readpage_inline(inode, &folio->page);
327  	else
328  		ret = block_read_full_folio(folio, ocfs2_get_block);
329  	unlock = 0;
330  
331  out_alloc:
332  	up_read(&oi->ip_alloc_sem);
333  out_inode_unlock:
334  	ocfs2_inode_unlock(inode, 0);
335  out:
336  	if (unlock)
337  		folio_unlock(folio);
338  	return ret;
339  }
340  
341  /*
342   * This is used only for read-ahead. Failures or difficult to handle
343   * situations are safe to ignore.
344   *
345   * Right now, we don't bother with BH_Boundary - in-inode extent lists
346   * are quite large (243 extents on 4k blocks), so most inodes don't
347   * grow out to a tree. If need be, detecting boundary extents could
348   * trivially be added in a future version of ocfs2_get_block().
349   */
350  static void ocfs2_readahead(struct readahead_control *rac)
351  {
352  	int ret;
353  	struct inode *inode = rac->mapping->host;
354  	struct ocfs2_inode_info *oi = OCFS2_I(inode);
355  
356  	/*
357  	 * Use the nonblocking flag for the dlm code to avoid page
358  	 * lock inversion, but don't bother with retrying.
359  	 */
360  	ret = ocfs2_inode_lock_full(inode, NULL, 0, OCFS2_LOCK_NONBLOCK);
361  	if (ret)
362  		return;
363  
364  	if (down_read_trylock(&oi->ip_alloc_sem) == 0)
365  		goto out_unlock;
366  
367  	/*
368  	 * Don't bother with inline-data. There isn't anything
369  	 * to read-ahead in that case anyway...
370  	 */
371  	if (oi->ip_dyn_features & OCFS2_INLINE_DATA_FL)
372  		goto out_up;
373  
374  	/*
375  	 * Check whether a remote node truncated this file - we just
376  	 * drop out in that case as it's not worth handling here.
377  	 */
378  	if (readahead_pos(rac) >= i_size_read(inode))
379  		goto out_up;
380  
381  	mpage_readahead(rac, ocfs2_get_block);
382  
383  out_up:
384  	up_read(&oi->ip_alloc_sem);
385  out_unlock:
386  	ocfs2_inode_unlock(inode, 0);
387  }
388  
389  /* Note: Because we don't support holes, our allocation has
390   * already happened (allocation writes zeros to the file data)
391   * so we don't have to worry about ordered writes in
392   * ocfs2_writepage.
393   *
394   * ->writepage is called during the process of invalidating the page cache
395   * during blocked lock processing.  It can't block on any cluster locks
396   * to during block mapping.  It's relying on the fact that the block
397   * mapping can't have disappeared under the dirty pages that it is
398   * being asked to write back.
399   */
400  static int ocfs2_writepage(struct page *page, struct writeback_control *wbc)
401  {
402  	trace_ocfs2_writepage(
403  		(unsigned long long)OCFS2_I(page->mapping->host)->ip_blkno,
404  		page->index);
405  
406  	return block_write_full_page(page, ocfs2_get_block, wbc);
407  }
408  
409  /* Taken from ext3. We don't necessarily need the full blown
410   * functionality yet, but IMHO it's better to cut and paste the whole
411   * thing so we can avoid introducing our own bugs (and easily pick up
412   * their fixes when they happen) --Mark */
413  int walk_page_buffers(	handle_t *handle,
414  			struct buffer_head *head,
415  			unsigned from,
416  			unsigned to,
417  			int *partial,
418  			int (*fn)(	handle_t *handle,
419  					struct buffer_head *bh))
420  {
421  	struct buffer_head *bh;
422  	unsigned block_start, block_end;
423  	unsigned blocksize = head->b_size;
424  	int err, ret = 0;
425  	struct buffer_head *next;
426  
427  	for (	bh = head, block_start = 0;
428  		ret == 0 && (bh != head || !block_start);
429  	    	block_start = block_end, bh = next)
430  	{
431  		next = bh->b_this_page;
432  		block_end = block_start + blocksize;
433  		if (block_end <= from || block_start >= to) {
434  			if (partial && !buffer_uptodate(bh))
435  				*partial = 1;
436  			continue;
437  		}
438  		err = (*fn)(handle, bh);
439  		if (!ret)
440  			ret = err;
441  	}
442  	return ret;
443  }
444  
445  static sector_t ocfs2_bmap(struct address_space *mapping, sector_t block)
446  {
447  	sector_t status;
448  	u64 p_blkno = 0;
449  	int err = 0;
450  	struct inode *inode = mapping->host;
451  
452  	trace_ocfs2_bmap((unsigned long long)OCFS2_I(inode)->ip_blkno,
453  			 (unsigned long long)block);
454  
455  	/*
456  	 * The swap code (ab-)uses ->bmap to get a block mapping and then
457  	 * bypasseÑ• the file system for actual I/O.  We really can't allow
458  	 * that on refcounted inodes, so we have to skip out here.  And yes,
459  	 * 0 is the magic code for a bmap error..
460  	 */
461  	if (ocfs2_is_refcount_inode(inode))
462  		return 0;
463  
464  	/* We don't need to lock journal system files, since they aren't
465  	 * accessed concurrently from multiple nodes.
466  	 */
467  	if (!INODE_JOURNAL(inode)) {
468  		err = ocfs2_inode_lock(inode, NULL, 0);
469  		if (err) {
470  			if (err != -ENOENT)
471  				mlog_errno(err);
472  			goto bail;
473  		}
474  		down_read(&OCFS2_I(inode)->ip_alloc_sem);
475  	}
476  
477  	if (!(OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL))
478  		err = ocfs2_extent_map_get_blocks(inode, block, &p_blkno, NULL,
479  						  NULL);
480  
481  	if (!INODE_JOURNAL(inode)) {
482  		up_read(&OCFS2_I(inode)->ip_alloc_sem);
483  		ocfs2_inode_unlock(inode, 0);
484  	}
485  
486  	if (err) {
487  		mlog(ML_ERROR, "get_blocks() failed, block = %llu\n",
488  		     (unsigned long long)block);
489  		mlog_errno(err);
490  		goto bail;
491  	}
492  
493  bail:
494  	status = err ? 0 : p_blkno;
495  
496  	return status;
497  }
498  
499  static bool ocfs2_release_folio(struct folio *folio, gfp_t wait)
500  {
501  	if (!folio_buffers(folio))
502  		return false;
503  	return try_to_free_buffers(folio);
504  }
505  
506  static void ocfs2_figure_cluster_boundaries(struct ocfs2_super *osb,
507  					    u32 cpos,
508  					    unsigned int *start,
509  					    unsigned int *end)
510  {
511  	unsigned int cluster_start = 0, cluster_end = PAGE_SIZE;
512  
513  	if (unlikely(PAGE_SHIFT > osb->s_clustersize_bits)) {
514  		unsigned int cpp;
515  
516  		cpp = 1 << (PAGE_SHIFT - osb->s_clustersize_bits);
517  
518  		cluster_start = cpos % cpp;
519  		cluster_start = cluster_start << osb->s_clustersize_bits;
520  
521  		cluster_end = cluster_start + osb->s_clustersize;
522  	}
523  
524  	BUG_ON(cluster_start > PAGE_SIZE);
525  	BUG_ON(cluster_end > PAGE_SIZE);
526  
527  	if (start)
528  		*start = cluster_start;
529  	if (end)
530  		*end = cluster_end;
531  }
532  
533  /*
534   * 'from' and 'to' are the region in the page to avoid zeroing.
535   *
536   * If pagesize > clustersize, this function will avoid zeroing outside
537   * of the cluster boundary.
538   *
539   * from == to == 0 is code for "zero the entire cluster region"
540   */
541  static void ocfs2_clear_page_regions(struct page *page,
542  				     struct ocfs2_super *osb, u32 cpos,
543  				     unsigned from, unsigned to)
544  {
545  	void *kaddr;
546  	unsigned int cluster_start, cluster_end;
547  
548  	ocfs2_figure_cluster_boundaries(osb, cpos, &cluster_start, &cluster_end);
549  
550  	kaddr = kmap_atomic(page);
551  
552  	if (from || to) {
553  		if (from > cluster_start)
554  			memset(kaddr + cluster_start, 0, from - cluster_start);
555  		if (to < cluster_end)
556  			memset(kaddr + to, 0, cluster_end - to);
557  	} else {
558  		memset(kaddr + cluster_start, 0, cluster_end - cluster_start);
559  	}
560  
561  	kunmap_atomic(kaddr);
562  }
563  
564  /*
565   * Nonsparse file systems fully allocate before we get to the write
566   * code. This prevents ocfs2_write() from tagging the write as an
567   * allocating one, which means ocfs2_map_page_blocks() might try to
568   * read-in the blocks at the tail of our file. Avoid reading them by
569   * testing i_size against each block offset.
570   */
571  static int ocfs2_should_read_blk(struct inode *inode, struct page *page,
572  				 unsigned int block_start)
573  {
574  	u64 offset = page_offset(page) + block_start;
575  
576  	if (ocfs2_sparse_alloc(OCFS2_SB(inode->i_sb)))
577  		return 1;
578  
579  	if (i_size_read(inode) > offset)
580  		return 1;
581  
582  	return 0;
583  }
584  
585  /*
586   * Some of this taken from __block_write_begin(). We already have our
587   * mapping by now though, and the entire write will be allocating or
588   * it won't, so not much need to use BH_New.
589   *
590   * This will also skip zeroing, which is handled externally.
591   */
592  int ocfs2_map_page_blocks(struct page *page, u64 *p_blkno,
593  			  struct inode *inode, unsigned int from,
594  			  unsigned int to, int new)
595  {
596  	int ret = 0;
597  	struct buffer_head *head, *bh, *wait[2], **wait_bh = wait;
598  	unsigned int block_end, block_start;
599  	unsigned int bsize = i_blocksize(inode);
600  
601  	if (!page_has_buffers(page))
602  		create_empty_buffers(page, bsize, 0);
603  
604  	head = page_buffers(page);
605  	for (bh = head, block_start = 0; bh != head || !block_start;
606  	     bh = bh->b_this_page, block_start += bsize) {
607  		block_end = block_start + bsize;
608  
609  		clear_buffer_new(bh);
610  
611  		/*
612  		 * Ignore blocks outside of our i/o range -
613  		 * they may belong to unallocated clusters.
614  		 */
615  		if (block_start >= to || block_end <= from) {
616  			if (PageUptodate(page))
617  				set_buffer_uptodate(bh);
618  			continue;
619  		}
620  
621  		/*
622  		 * For an allocating write with cluster size >= page
623  		 * size, we always write the entire page.
624  		 */
625  		if (new)
626  			set_buffer_new(bh);
627  
628  		if (!buffer_mapped(bh)) {
629  			map_bh(bh, inode->i_sb, *p_blkno);
630  			clean_bdev_bh_alias(bh);
631  		}
632  
633  		if (PageUptodate(page)) {
634  			set_buffer_uptodate(bh);
635  		} else if (!buffer_uptodate(bh) && !buffer_delay(bh) &&
636  			   !buffer_new(bh) &&
637  			   ocfs2_should_read_blk(inode, page, block_start) &&
638  			   (block_start < from || block_end > to)) {
639  			ll_rw_block(REQ_OP_READ, 1, &bh);
640  			*wait_bh++=bh;
641  		}
642  
643  		*p_blkno = *p_blkno + 1;
644  	}
645  
646  	/*
647  	 * If we issued read requests - let them complete.
648  	 */
649  	while(wait_bh > wait) {
650  		wait_on_buffer(*--wait_bh);
651  		if (!buffer_uptodate(*wait_bh))
652  			ret = -EIO;
653  	}
654  
655  	if (ret == 0 || !new)
656  		return ret;
657  
658  	/*
659  	 * If we get -EIO above, zero out any newly allocated blocks
660  	 * to avoid exposing stale data.
661  	 */
662  	bh = head;
663  	block_start = 0;
664  	do {
665  		block_end = block_start + bsize;
666  		if (block_end <= from)
667  			goto next_bh;
668  		if (block_start >= to)
669  			break;
670  
671  		zero_user(page, block_start, bh->b_size);
672  		set_buffer_uptodate(bh);
673  		mark_buffer_dirty(bh);
674  
675  next_bh:
676  		block_start = block_end;
677  		bh = bh->b_this_page;
678  	} while (bh != head);
679  
680  	return ret;
681  }
682  
683  #if (PAGE_SIZE >= OCFS2_MAX_CLUSTERSIZE)
684  #define OCFS2_MAX_CTXT_PAGES	1
685  #else
686  #define OCFS2_MAX_CTXT_PAGES	(OCFS2_MAX_CLUSTERSIZE / PAGE_SIZE)
687  #endif
688  
689  #define OCFS2_MAX_CLUSTERS_PER_PAGE	(PAGE_SIZE / OCFS2_MIN_CLUSTERSIZE)
690  
691  struct ocfs2_unwritten_extent {
692  	struct list_head	ue_node;
693  	struct list_head	ue_ip_node;
694  	u32			ue_cpos;
695  	u32			ue_phys;
696  };
697  
698  /*
699   * Describe the state of a single cluster to be written to.
700   */
701  struct ocfs2_write_cluster_desc {
702  	u32		c_cpos;
703  	u32		c_phys;
704  	/*
705  	 * Give this a unique field because c_phys eventually gets
706  	 * filled.
707  	 */
708  	unsigned	c_new;
709  	unsigned	c_clear_unwritten;
710  	unsigned	c_needs_zero;
711  };
712  
713  struct ocfs2_write_ctxt {
714  	/* Logical cluster position / len of write */
715  	u32				w_cpos;
716  	u32				w_clen;
717  
718  	/* First cluster allocated in a nonsparse extend */
719  	u32				w_first_new_cpos;
720  
721  	/* Type of caller. Must be one of buffer, mmap, direct.  */
722  	ocfs2_write_type_t		w_type;
723  
724  	struct ocfs2_write_cluster_desc	w_desc[OCFS2_MAX_CLUSTERS_PER_PAGE];
725  
726  	/*
727  	 * This is true if page_size > cluster_size.
728  	 *
729  	 * It triggers a set of special cases during write which might
730  	 * have to deal with allocating writes to partial pages.
731  	 */
732  	unsigned int			w_large_pages;
733  
734  	/*
735  	 * Pages involved in this write.
736  	 *
737  	 * w_target_page is the page being written to by the user.
738  	 *
739  	 * w_pages is an array of pages which always contains
740  	 * w_target_page, and in the case of an allocating write with
741  	 * page_size < cluster size, it will contain zero'd and mapped
742  	 * pages adjacent to w_target_page which need to be written
743  	 * out in so that future reads from that region will get
744  	 * zero's.
745  	 */
746  	unsigned int			w_num_pages;
747  	struct page			*w_pages[OCFS2_MAX_CTXT_PAGES];
748  	struct page			*w_target_page;
749  
750  	/*
751  	 * w_target_locked is used for page_mkwrite path indicating no unlocking
752  	 * against w_target_page in ocfs2_write_end_nolock.
753  	 */
754  	unsigned int			w_target_locked:1;
755  
756  	/*
757  	 * ocfs2_write_end() uses this to know what the real range to
758  	 * write in the target should be.
759  	 */
760  	unsigned int			w_target_from;
761  	unsigned int			w_target_to;
762  
763  	/*
764  	 * We could use journal_current_handle() but this is cleaner,
765  	 * IMHO -Mark
766  	 */
767  	handle_t			*w_handle;
768  
769  	struct buffer_head		*w_di_bh;
770  
771  	struct ocfs2_cached_dealloc_ctxt w_dealloc;
772  
773  	struct list_head		w_unwritten_list;
774  	unsigned int			w_unwritten_count;
775  };
776  
777  void ocfs2_unlock_and_free_pages(struct page **pages, int num_pages)
778  {
779  	int i;
780  
781  	for(i = 0; i < num_pages; i++) {
782  		if (pages[i]) {
783  			unlock_page(pages[i]);
784  			mark_page_accessed(pages[i]);
785  			put_page(pages[i]);
786  		}
787  	}
788  }
789  
790  static void ocfs2_unlock_pages(struct ocfs2_write_ctxt *wc)
791  {
792  	int i;
793  
794  	/*
795  	 * w_target_locked is only set to true in the page_mkwrite() case.
796  	 * The intent is to allow us to lock the target page from write_begin()
797  	 * to write_end(). The caller must hold a ref on w_target_page.
798  	 */
799  	if (wc->w_target_locked) {
800  		BUG_ON(!wc->w_target_page);
801  		for (i = 0; i < wc->w_num_pages; i++) {
802  			if (wc->w_target_page == wc->w_pages[i]) {
803  				wc->w_pages[i] = NULL;
804  				break;
805  			}
806  		}
807  		mark_page_accessed(wc->w_target_page);
808  		put_page(wc->w_target_page);
809  	}
810  	ocfs2_unlock_and_free_pages(wc->w_pages, wc->w_num_pages);
811  }
812  
813  static void ocfs2_free_unwritten_list(struct inode *inode,
814  				 struct list_head *head)
815  {
816  	struct ocfs2_inode_info *oi = OCFS2_I(inode);
817  	struct ocfs2_unwritten_extent *ue = NULL, *tmp = NULL;
818  
819  	list_for_each_entry_safe(ue, tmp, head, ue_node) {
820  		list_del(&ue->ue_node);
821  		spin_lock(&oi->ip_lock);
822  		list_del(&ue->ue_ip_node);
823  		spin_unlock(&oi->ip_lock);
824  		kfree(ue);
825  	}
826  }
827  
828  static void ocfs2_free_write_ctxt(struct inode *inode,
829  				  struct ocfs2_write_ctxt *wc)
830  {
831  	ocfs2_free_unwritten_list(inode, &wc->w_unwritten_list);
832  	ocfs2_unlock_pages(wc);
833  	brelse(wc->w_di_bh);
834  	kfree(wc);
835  }
836  
837  static int ocfs2_alloc_write_ctxt(struct ocfs2_write_ctxt **wcp,
838  				  struct ocfs2_super *osb, loff_t pos,
839  				  unsigned len, ocfs2_write_type_t type,
840  				  struct buffer_head *di_bh)
841  {
842  	u32 cend;
843  	struct ocfs2_write_ctxt *wc;
844  
845  	wc = kzalloc(sizeof(struct ocfs2_write_ctxt), GFP_NOFS);
846  	if (!wc)
847  		return -ENOMEM;
848  
849  	wc->w_cpos = pos >> osb->s_clustersize_bits;
850  	wc->w_first_new_cpos = UINT_MAX;
851  	cend = (pos + len - 1) >> osb->s_clustersize_bits;
852  	wc->w_clen = cend - wc->w_cpos + 1;
853  	get_bh(di_bh);
854  	wc->w_di_bh = di_bh;
855  	wc->w_type = type;
856  
857  	if (unlikely(PAGE_SHIFT > osb->s_clustersize_bits))
858  		wc->w_large_pages = 1;
859  	else
860  		wc->w_large_pages = 0;
861  
862  	ocfs2_init_dealloc_ctxt(&wc->w_dealloc);
863  	INIT_LIST_HEAD(&wc->w_unwritten_list);
864  
865  	*wcp = wc;
866  
867  	return 0;
868  }
869  
870  /*
871   * If a page has any new buffers, zero them out here, and mark them uptodate
872   * and dirty so they'll be written out (in order to prevent uninitialised
873   * block data from leaking). And clear the new bit.
874   */
875  static void ocfs2_zero_new_buffers(struct page *page, unsigned from, unsigned to)
876  {
877  	unsigned int block_start, block_end;
878  	struct buffer_head *head, *bh;
879  
880  	BUG_ON(!PageLocked(page));
881  	if (!page_has_buffers(page))
882  		return;
883  
884  	bh = head = page_buffers(page);
885  	block_start = 0;
886  	do {
887  		block_end = block_start + bh->b_size;
888  
889  		if (buffer_new(bh)) {
890  			if (block_end > from && block_start < to) {
891  				if (!PageUptodate(page)) {
892  					unsigned start, end;
893  
894  					start = max(from, block_start);
895  					end = min(to, block_end);
896  
897  					zero_user_segment(page, start, end);
898  					set_buffer_uptodate(bh);
899  				}
900  
901  				clear_buffer_new(bh);
902  				mark_buffer_dirty(bh);
903  			}
904  		}
905  
906  		block_start = block_end;
907  		bh = bh->b_this_page;
908  	} while (bh != head);
909  }
910  
911  /*
912   * Only called when we have a failure during allocating write to write
913   * zero's to the newly allocated region.
914   */
915  static void ocfs2_write_failure(struct inode *inode,
916  				struct ocfs2_write_ctxt *wc,
917  				loff_t user_pos, unsigned user_len)
918  {
919  	int i;
920  	unsigned from = user_pos & (PAGE_SIZE - 1),
921  		to = user_pos + user_len;
922  	struct page *tmppage;
923  
924  	if (wc->w_target_page)
925  		ocfs2_zero_new_buffers(wc->w_target_page, from, to);
926  
927  	for(i = 0; i < wc->w_num_pages; i++) {
928  		tmppage = wc->w_pages[i];
929  
930  		if (tmppage && page_has_buffers(tmppage)) {
931  			if (ocfs2_should_order_data(inode))
932  				ocfs2_jbd2_inode_add_write(wc->w_handle, inode,
933  							   user_pos, user_len);
934  
935  			block_commit_write(tmppage, from, to);
936  		}
937  	}
938  }
939  
940  static int ocfs2_prepare_page_for_write(struct inode *inode, u64 *p_blkno,
941  					struct ocfs2_write_ctxt *wc,
942  					struct page *page, u32 cpos,
943  					loff_t user_pos, unsigned user_len,
944  					int new)
945  {
946  	int ret;
947  	unsigned int map_from = 0, map_to = 0;
948  	unsigned int cluster_start, cluster_end;
949  	unsigned int user_data_from = 0, user_data_to = 0;
950  
951  	ocfs2_figure_cluster_boundaries(OCFS2_SB(inode->i_sb), cpos,
952  					&cluster_start, &cluster_end);
953  
954  	/* treat the write as new if the a hole/lseek spanned across
955  	 * the page boundary.
956  	 */
957  	new = new | ((i_size_read(inode) <= page_offset(page)) &&
958  			(page_offset(page) <= user_pos));
959  
960  	if (page == wc->w_target_page) {
961  		map_from = user_pos & (PAGE_SIZE - 1);
962  		map_to = map_from + user_len;
963  
964  		if (new)
965  			ret = ocfs2_map_page_blocks(page, p_blkno, inode,
966  						    cluster_start, cluster_end,
967  						    new);
968  		else
969  			ret = ocfs2_map_page_blocks(page, p_blkno, inode,
970  						    map_from, map_to, new);
971  		if (ret) {
972  			mlog_errno(ret);
973  			goto out;
974  		}
975  
976  		user_data_from = map_from;
977  		user_data_to = map_to;
978  		if (new) {
979  			map_from = cluster_start;
980  			map_to = cluster_end;
981  		}
982  	} else {
983  		/*
984  		 * If we haven't allocated the new page yet, we
985  		 * shouldn't be writing it out without copying user
986  		 * data. This is likely a math error from the caller.
987  		 */
988  		BUG_ON(!new);
989  
990  		map_from = cluster_start;
991  		map_to = cluster_end;
992  
993  		ret = ocfs2_map_page_blocks(page, p_blkno, inode,
994  					    cluster_start, cluster_end, new);
995  		if (ret) {
996  			mlog_errno(ret);
997  			goto out;
998  		}
999  	}
1000  
1001  	/*
1002  	 * Parts of newly allocated pages need to be zero'd.
1003  	 *
1004  	 * Above, we have also rewritten 'to' and 'from' - as far as
1005  	 * the rest of the function is concerned, the entire cluster
1006  	 * range inside of a page needs to be written.
1007  	 *
1008  	 * We can skip this if the page is up to date - it's already
1009  	 * been zero'd from being read in as a hole.
1010  	 */
1011  	if (new && !PageUptodate(page))
1012  		ocfs2_clear_page_regions(page, OCFS2_SB(inode->i_sb),
1013  					 cpos, user_data_from, user_data_to);
1014  
1015  	flush_dcache_page(page);
1016  
1017  out:
1018  	return ret;
1019  }
1020  
1021  /*
1022   * This function will only grab one clusters worth of pages.
1023   */
1024  static int ocfs2_grab_pages_for_write(struct address_space *mapping,
1025  				      struct ocfs2_write_ctxt *wc,
1026  				      u32 cpos, loff_t user_pos,
1027  				      unsigned user_len, int new,
1028  				      struct page *mmap_page)
1029  {
1030  	int ret = 0, i;
1031  	unsigned long start, target_index, end_index, index;
1032  	struct inode *inode = mapping->host;
1033  	loff_t last_byte;
1034  
1035  	target_index = user_pos >> PAGE_SHIFT;
1036  
1037  	/*
1038  	 * Figure out how many pages we'll be manipulating here. For
1039  	 * non allocating write, we just change the one
1040  	 * page. Otherwise, we'll need a whole clusters worth.  If we're
1041  	 * writing past i_size, we only need enough pages to cover the
1042  	 * last page of the write.
1043  	 */
1044  	if (new) {
1045  		wc->w_num_pages = ocfs2_pages_per_cluster(inode->i_sb);
1046  		start = ocfs2_align_clusters_to_page_index(inode->i_sb, cpos);
1047  		/*
1048  		 * We need the index *past* the last page we could possibly
1049  		 * touch.  This is the page past the end of the write or
1050  		 * i_size, whichever is greater.
1051  		 */
1052  		last_byte = max(user_pos + user_len, i_size_read(inode));
1053  		BUG_ON(last_byte < 1);
1054  		end_index = ((last_byte - 1) >> PAGE_SHIFT) + 1;
1055  		if ((start + wc->w_num_pages) > end_index)
1056  			wc->w_num_pages = end_index - start;
1057  	} else {
1058  		wc->w_num_pages = 1;
1059  		start = target_index;
1060  	}
1061  	end_index = (user_pos + user_len - 1) >> PAGE_SHIFT;
1062  
1063  	for(i = 0; i < wc->w_num_pages; i++) {
1064  		index = start + i;
1065  
1066  		if (index >= target_index && index <= end_index &&
1067  		    wc->w_type == OCFS2_WRITE_MMAP) {
1068  			/*
1069  			 * ocfs2_pagemkwrite() is a little different
1070  			 * and wants us to directly use the page
1071  			 * passed in.
1072  			 */
1073  			lock_page(mmap_page);
1074  
1075  			/* Exit and let the caller retry */
1076  			if (mmap_page->mapping != mapping) {
1077  				WARN_ON(mmap_page->mapping);
1078  				unlock_page(mmap_page);
1079  				ret = -EAGAIN;
1080  				goto out;
1081  			}
1082  
1083  			get_page(mmap_page);
1084  			wc->w_pages[i] = mmap_page;
1085  			wc->w_target_locked = true;
1086  		} else if (index >= target_index && index <= end_index &&
1087  			   wc->w_type == OCFS2_WRITE_DIRECT) {
1088  			/* Direct write has no mapping page. */
1089  			wc->w_pages[i] = NULL;
1090  			continue;
1091  		} else {
1092  			wc->w_pages[i] = find_or_create_page(mapping, index,
1093  							     GFP_NOFS);
1094  			if (!wc->w_pages[i]) {
1095  				ret = -ENOMEM;
1096  				mlog_errno(ret);
1097  				goto out;
1098  			}
1099  		}
1100  		wait_for_stable_page(wc->w_pages[i]);
1101  
1102  		if (index == target_index)
1103  			wc->w_target_page = wc->w_pages[i];
1104  	}
1105  out:
1106  	if (ret)
1107  		wc->w_target_locked = false;
1108  	return ret;
1109  }
1110  
1111  /*
1112   * Prepare a single cluster for write one cluster into the file.
1113   */
1114  static int ocfs2_write_cluster(struct address_space *mapping,
1115  			       u32 *phys, unsigned int new,
1116  			       unsigned int clear_unwritten,
1117  			       unsigned int should_zero,
1118  			       struct ocfs2_alloc_context *data_ac,
1119  			       struct ocfs2_alloc_context *meta_ac,
1120  			       struct ocfs2_write_ctxt *wc, u32 cpos,
1121  			       loff_t user_pos, unsigned user_len)
1122  {
1123  	int ret, i;
1124  	u64 p_blkno;
1125  	struct inode *inode = mapping->host;
1126  	struct ocfs2_extent_tree et;
1127  	int bpc = ocfs2_clusters_to_blocks(inode->i_sb, 1);
1128  
1129  	if (new) {
1130  		u32 tmp_pos;
1131  
1132  		/*
1133  		 * This is safe to call with the page locks - it won't take
1134  		 * any additional semaphores or cluster locks.
1135  		 */
1136  		tmp_pos = cpos;
1137  		ret = ocfs2_add_inode_data(OCFS2_SB(inode->i_sb), inode,
1138  					   &tmp_pos, 1, !clear_unwritten,
1139  					   wc->w_di_bh, wc->w_handle,
1140  					   data_ac, meta_ac, NULL);
1141  		/*
1142  		 * This shouldn't happen because we must have already
1143  		 * calculated the correct meta data allocation required. The
1144  		 * internal tree allocation code should know how to increase
1145  		 * transaction credits itself.
1146  		 *
1147  		 * If need be, we could handle -EAGAIN for a
1148  		 * RESTART_TRANS here.
1149  		 */
1150  		mlog_bug_on_msg(ret == -EAGAIN,
1151  				"Inode %llu: EAGAIN return during allocation.\n",
1152  				(unsigned long long)OCFS2_I(inode)->ip_blkno);
1153  		if (ret < 0) {
1154  			mlog_errno(ret);
1155  			goto out;
1156  		}
1157  	} else if (clear_unwritten) {
1158  		ocfs2_init_dinode_extent_tree(&et, INODE_CACHE(inode),
1159  					      wc->w_di_bh);
1160  		ret = ocfs2_mark_extent_written(inode, &et,
1161  						wc->w_handle, cpos, 1, *phys,
1162  						meta_ac, &wc->w_dealloc);
1163  		if (ret < 0) {
1164  			mlog_errno(ret);
1165  			goto out;
1166  		}
1167  	}
1168  
1169  	/*
1170  	 * The only reason this should fail is due to an inability to
1171  	 * find the extent added.
1172  	 */
1173  	ret = ocfs2_get_clusters(inode, cpos, phys, NULL, NULL);
1174  	if (ret < 0) {
1175  		mlog(ML_ERROR, "Get physical blkno failed for inode %llu, "
1176  			    "at logical cluster %u",
1177  			    (unsigned long long)OCFS2_I(inode)->ip_blkno, cpos);
1178  		goto out;
1179  	}
1180  
1181  	BUG_ON(*phys == 0);
1182  
1183  	p_blkno = ocfs2_clusters_to_blocks(inode->i_sb, *phys);
1184  	if (!should_zero)
1185  		p_blkno += (user_pos >> inode->i_sb->s_blocksize_bits) & (u64)(bpc - 1);
1186  
1187  	for(i = 0; i < wc->w_num_pages; i++) {
1188  		int tmpret;
1189  
1190  		/* This is the direct io target page. */
1191  		if (wc->w_pages[i] == NULL) {
1192  			p_blkno++;
1193  			continue;
1194  		}
1195  
1196  		tmpret = ocfs2_prepare_page_for_write(inode, &p_blkno, wc,
1197  						      wc->w_pages[i], cpos,
1198  						      user_pos, user_len,
1199  						      should_zero);
1200  		if (tmpret) {
1201  			mlog_errno(tmpret);
1202  			if (ret == 0)
1203  				ret = tmpret;
1204  		}
1205  	}
1206  
1207  	/*
1208  	 * We only have cleanup to do in case of allocating write.
1209  	 */
1210  	if (ret && new)
1211  		ocfs2_write_failure(inode, wc, user_pos, user_len);
1212  
1213  out:
1214  
1215  	return ret;
1216  }
1217  
1218  static int ocfs2_write_cluster_by_desc(struct address_space *mapping,
1219  				       struct ocfs2_alloc_context *data_ac,
1220  				       struct ocfs2_alloc_context *meta_ac,
1221  				       struct ocfs2_write_ctxt *wc,
1222  				       loff_t pos, unsigned len)
1223  {
1224  	int ret, i;
1225  	loff_t cluster_off;
1226  	unsigned int local_len = len;
1227  	struct ocfs2_write_cluster_desc *desc;
1228  	struct ocfs2_super *osb = OCFS2_SB(mapping->host->i_sb);
1229  
1230  	for (i = 0; i < wc->w_clen; i++) {
1231  		desc = &wc->w_desc[i];
1232  
1233  		/*
1234  		 * We have to make sure that the total write passed in
1235  		 * doesn't extend past a single cluster.
1236  		 */
1237  		local_len = len;
1238  		cluster_off = pos & (osb->s_clustersize - 1);
1239  		if ((cluster_off + local_len) > osb->s_clustersize)
1240  			local_len = osb->s_clustersize - cluster_off;
1241  
1242  		ret = ocfs2_write_cluster(mapping, &desc->c_phys,
1243  					  desc->c_new,
1244  					  desc->c_clear_unwritten,
1245  					  desc->c_needs_zero,
1246  					  data_ac, meta_ac,
1247  					  wc, desc->c_cpos, pos, local_len);
1248  		if (ret) {
1249  			mlog_errno(ret);
1250  			goto out;
1251  		}
1252  
1253  		len -= local_len;
1254  		pos += local_len;
1255  	}
1256  
1257  	ret = 0;
1258  out:
1259  	return ret;
1260  }
1261  
1262  /*
1263   * ocfs2_write_end() wants to know which parts of the target page it
1264   * should complete the write on. It's easiest to compute them ahead of
1265   * time when a more complete view of the write is available.
1266   */
1267  static void ocfs2_set_target_boundaries(struct ocfs2_super *osb,
1268  					struct ocfs2_write_ctxt *wc,
1269  					loff_t pos, unsigned len, int alloc)
1270  {
1271  	struct ocfs2_write_cluster_desc *desc;
1272  
1273  	wc->w_target_from = pos & (PAGE_SIZE - 1);
1274  	wc->w_target_to = wc->w_target_from + len;
1275  
1276  	if (alloc == 0)
1277  		return;
1278  
1279  	/*
1280  	 * Allocating write - we may have different boundaries based
1281  	 * on page size and cluster size.
1282  	 *
1283  	 * NOTE: We can no longer compute one value from the other as
1284  	 * the actual write length and user provided length may be
1285  	 * different.
1286  	 */
1287  
1288  	if (wc->w_large_pages) {
1289  		/*
1290  		 * We only care about the 1st and last cluster within
1291  		 * our range and whether they should be zero'd or not. Either
1292  		 * value may be extended out to the start/end of a
1293  		 * newly allocated cluster.
1294  		 */
1295  		desc = &wc->w_desc[0];
1296  		if (desc->c_needs_zero)
1297  			ocfs2_figure_cluster_boundaries(osb,
1298  							desc->c_cpos,
1299  							&wc->w_target_from,
1300  							NULL);
1301  
1302  		desc = &wc->w_desc[wc->w_clen - 1];
1303  		if (desc->c_needs_zero)
1304  			ocfs2_figure_cluster_boundaries(osb,
1305  							desc->c_cpos,
1306  							NULL,
1307  							&wc->w_target_to);
1308  	} else {
1309  		wc->w_target_from = 0;
1310  		wc->w_target_to = PAGE_SIZE;
1311  	}
1312  }
1313  
1314  /*
1315   * Check if this extent is marked UNWRITTEN by direct io. If so, we need not to
1316   * do the zero work. And should not to clear UNWRITTEN since it will be cleared
1317   * by the direct io procedure.
1318   * If this is a new extent that allocated by direct io, we should mark it in
1319   * the ip_unwritten_list.
1320   */
1321  static int ocfs2_unwritten_check(struct inode *inode,
1322  				 struct ocfs2_write_ctxt *wc,
1323  				 struct ocfs2_write_cluster_desc *desc)
1324  {
1325  	struct ocfs2_inode_info *oi = OCFS2_I(inode);
1326  	struct ocfs2_unwritten_extent *ue = NULL, *new = NULL;
1327  	int ret = 0;
1328  
1329  	if (!desc->c_needs_zero)
1330  		return 0;
1331  
1332  retry:
1333  	spin_lock(&oi->ip_lock);
1334  	/* Needs not to zero no metter buffer or direct. The one who is zero
1335  	 * the cluster is doing zero. And he will clear unwritten after all
1336  	 * cluster io finished. */
1337  	list_for_each_entry(ue, &oi->ip_unwritten_list, ue_ip_node) {
1338  		if (desc->c_cpos == ue->ue_cpos) {
1339  			BUG_ON(desc->c_new);
1340  			desc->c_needs_zero = 0;
1341  			desc->c_clear_unwritten = 0;
1342  			goto unlock;
1343  		}
1344  	}
1345  
1346  	if (wc->w_type != OCFS2_WRITE_DIRECT)
1347  		goto unlock;
1348  
1349  	if (new == NULL) {
1350  		spin_unlock(&oi->ip_lock);
1351  		new = kmalloc(sizeof(struct ocfs2_unwritten_extent),
1352  			     GFP_NOFS);
1353  		if (new == NULL) {
1354  			ret = -ENOMEM;
1355  			goto out;
1356  		}
1357  		goto retry;
1358  	}
1359  	/* This direct write will doing zero. */
1360  	new->ue_cpos = desc->c_cpos;
1361  	new->ue_phys = desc->c_phys;
1362  	desc->c_clear_unwritten = 0;
1363  	list_add_tail(&new->ue_ip_node, &oi->ip_unwritten_list);
1364  	list_add_tail(&new->ue_node, &wc->w_unwritten_list);
1365  	wc->w_unwritten_count++;
1366  	new = NULL;
1367  unlock:
1368  	spin_unlock(&oi->ip_lock);
1369  out:
1370  	kfree(new);
1371  	return ret;
1372  }
1373  
1374  /*
1375   * Populate each single-cluster write descriptor in the write context
1376   * with information about the i/o to be done.
1377   *
1378   * Returns the number of clusters that will have to be allocated, as
1379   * well as a worst case estimate of the number of extent records that
1380   * would have to be created during a write to an unwritten region.
1381   */
1382  static int ocfs2_populate_write_desc(struct inode *inode,
1383  				     struct ocfs2_write_ctxt *wc,
1384  				     unsigned int *clusters_to_alloc,
1385  				     unsigned int *extents_to_split)
1386  {
1387  	int ret;
1388  	struct ocfs2_write_cluster_desc *desc;
1389  	unsigned int num_clusters = 0;
1390  	unsigned int ext_flags = 0;
1391  	u32 phys = 0;
1392  	int i;
1393  
1394  	*clusters_to_alloc = 0;
1395  	*extents_to_split = 0;
1396  
1397  	for (i = 0; i < wc->w_clen; i++) {
1398  		desc = &wc->w_desc[i];
1399  		desc->c_cpos = wc->w_cpos + i;
1400  
1401  		if (num_clusters == 0) {
1402  			/*
1403  			 * Need to look up the next extent record.
1404  			 */
1405  			ret = ocfs2_get_clusters(inode, desc->c_cpos, &phys,
1406  						 &num_clusters, &ext_flags);
1407  			if (ret) {
1408  				mlog_errno(ret);
1409  				goto out;
1410  			}
1411  
1412  			/* We should already CoW the refcountd extent. */
1413  			BUG_ON(ext_flags & OCFS2_EXT_REFCOUNTED);
1414  
1415  			/*
1416  			 * Assume worst case - that we're writing in
1417  			 * the middle of the extent.
1418  			 *
1419  			 * We can assume that the write proceeds from
1420  			 * left to right, in which case the extent
1421  			 * insert code is smart enough to coalesce the
1422  			 * next splits into the previous records created.
1423  			 */
1424  			if (ext_flags & OCFS2_EXT_UNWRITTEN)
1425  				*extents_to_split = *extents_to_split + 2;
1426  		} else if (phys) {
1427  			/*
1428  			 * Only increment phys if it doesn't describe
1429  			 * a hole.
1430  			 */
1431  			phys++;
1432  		}
1433  
1434  		/*
1435  		 * If w_first_new_cpos is < UINT_MAX, we have a non-sparse
1436  		 * file that got extended.  w_first_new_cpos tells us
1437  		 * where the newly allocated clusters are so we can
1438  		 * zero them.
1439  		 */
1440  		if (desc->c_cpos >= wc->w_first_new_cpos) {
1441  			BUG_ON(phys == 0);
1442  			desc->c_needs_zero = 1;
1443  		}
1444  
1445  		desc->c_phys = phys;
1446  		if (phys == 0) {
1447  			desc->c_new = 1;
1448  			desc->c_needs_zero = 1;
1449  			desc->c_clear_unwritten = 1;
1450  			*clusters_to_alloc = *clusters_to_alloc + 1;
1451  		}
1452  
1453  		if (ext_flags & OCFS2_EXT_UNWRITTEN) {
1454  			desc->c_clear_unwritten = 1;
1455  			desc->c_needs_zero = 1;
1456  		}
1457  
1458  		ret = ocfs2_unwritten_check(inode, wc, desc);
1459  		if (ret) {
1460  			mlog_errno(ret);
1461  			goto out;
1462  		}
1463  
1464  		num_clusters--;
1465  	}
1466  
1467  	ret = 0;
1468  out:
1469  	return ret;
1470  }
1471  
1472  static int ocfs2_write_begin_inline(struct address_space *mapping,
1473  				    struct inode *inode,
1474  				    struct ocfs2_write_ctxt *wc)
1475  {
1476  	int ret;
1477  	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
1478  	struct page *page;
1479  	handle_t *handle;
1480  	struct ocfs2_dinode *di = (struct ocfs2_dinode *)wc->w_di_bh->b_data;
1481  
1482  	handle = ocfs2_start_trans(osb, OCFS2_INODE_UPDATE_CREDITS);
1483  	if (IS_ERR(handle)) {
1484  		ret = PTR_ERR(handle);
1485  		mlog_errno(ret);
1486  		goto out;
1487  	}
1488  
1489  	page = find_or_create_page(mapping, 0, GFP_NOFS);
1490  	if (!page) {
1491  		ocfs2_commit_trans(osb, handle);
1492  		ret = -ENOMEM;
1493  		mlog_errno(ret);
1494  		goto out;
1495  	}
1496  	/*
1497  	 * If we don't set w_num_pages then this page won't get unlocked
1498  	 * and freed on cleanup of the write context.
1499  	 */
1500  	wc->w_pages[0] = wc->w_target_page = page;
1501  	wc->w_num_pages = 1;
1502  
1503  	ret = ocfs2_journal_access_di(handle, INODE_CACHE(inode), wc->w_di_bh,
1504  				      OCFS2_JOURNAL_ACCESS_WRITE);
1505  	if (ret) {
1506  		ocfs2_commit_trans(osb, handle);
1507  
1508  		mlog_errno(ret);
1509  		goto out;
1510  	}
1511  
1512  	if (!(OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL))
1513  		ocfs2_set_inode_data_inline(inode, di);
1514  
1515  	if (!PageUptodate(page)) {
1516  		ret = ocfs2_read_inline_data(inode, page, wc->w_di_bh);
1517  		if (ret) {
1518  			ocfs2_commit_trans(osb, handle);
1519  
1520  			goto out;
1521  		}
1522  	}
1523  
1524  	wc->w_handle = handle;
1525  out:
1526  	return ret;
1527  }
1528  
1529  int ocfs2_size_fits_inline_data(struct buffer_head *di_bh, u64 new_size)
1530  {
1531  	struct ocfs2_dinode *di = (struct ocfs2_dinode *)di_bh->b_data;
1532  
1533  	if (new_size <= le16_to_cpu(di->id2.i_data.id_count))
1534  		return 1;
1535  	return 0;
1536  }
1537  
1538  static int ocfs2_try_to_write_inline_data(struct address_space *mapping,
1539  					  struct inode *inode, loff_t pos,
1540  					  unsigned len, struct page *mmap_page,
1541  					  struct ocfs2_write_ctxt *wc)
1542  {
1543  	int ret, written = 0;
1544  	loff_t end = pos + len;
1545  	struct ocfs2_inode_info *oi = OCFS2_I(inode);
1546  	struct ocfs2_dinode *di = NULL;
1547  
1548  	trace_ocfs2_try_to_write_inline_data((unsigned long long)oi->ip_blkno,
1549  					     len, (unsigned long long)pos,
1550  					     oi->ip_dyn_features);
1551  
1552  	/*
1553  	 * Handle inodes which already have inline data 1st.
1554  	 */
1555  	if (oi->ip_dyn_features & OCFS2_INLINE_DATA_FL) {
1556  		if (mmap_page == NULL &&
1557  		    ocfs2_size_fits_inline_data(wc->w_di_bh, end))
1558  			goto do_inline_write;
1559  
1560  		/*
1561  		 * The write won't fit - we have to give this inode an
1562  		 * inline extent list now.
1563  		 */
1564  		ret = ocfs2_convert_inline_data_to_extents(inode, wc->w_di_bh);
1565  		if (ret)
1566  			mlog_errno(ret);
1567  		goto out;
1568  	}
1569  
1570  	/*
1571  	 * Check whether the inode can accept inline data.
1572  	 */
1573  	if (oi->ip_clusters != 0 || i_size_read(inode) != 0)
1574  		return 0;
1575  
1576  	/*
1577  	 * Check whether the write can fit.
1578  	 */
1579  	di = (struct ocfs2_dinode *)wc->w_di_bh->b_data;
1580  	if (mmap_page ||
1581  	    end > ocfs2_max_inline_data_with_xattr(inode->i_sb, di))
1582  		return 0;
1583  
1584  do_inline_write:
1585  	ret = ocfs2_write_begin_inline(mapping, inode, wc);
1586  	if (ret) {
1587  		mlog_errno(ret);
1588  		goto out;
1589  	}
1590  
1591  	/*
1592  	 * This signals to the caller that the data can be written
1593  	 * inline.
1594  	 */
1595  	written = 1;
1596  out:
1597  	return written ? written : ret;
1598  }
1599  
1600  /*
1601   * This function only does anything for file systems which can't
1602   * handle sparse files.
1603   *
1604   * What we want to do here is fill in any hole between the current end
1605   * of allocation and the end of our write. That way the rest of the
1606   * write path can treat it as an non-allocating write, which has no
1607   * special case code for sparse/nonsparse files.
1608   */
1609  static int ocfs2_expand_nonsparse_inode(struct inode *inode,
1610  					struct buffer_head *di_bh,
1611  					loff_t pos, unsigned len,
1612  					struct ocfs2_write_ctxt *wc)
1613  {
1614  	int ret;
1615  	loff_t newsize = pos + len;
1616  
1617  	BUG_ON(ocfs2_sparse_alloc(OCFS2_SB(inode->i_sb)));
1618  
1619  	if (newsize <= i_size_read(inode))
1620  		return 0;
1621  
1622  	ret = ocfs2_extend_no_holes(inode, di_bh, newsize, pos);
1623  	if (ret)
1624  		mlog_errno(ret);
1625  
1626  	/* There is no wc if this is call from direct. */
1627  	if (wc)
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  int ocfs2_write_begin_nolock(struct address_space *mapping,
1647  			     loff_t pos, unsigned len, ocfs2_write_type_t type,
1648  			     struct page **pagep, void **fsdata,
1649  			     struct buffer_head *di_bh, struct page *mmap_page)
1650  {
1651  	int ret, cluster_of_pages, credits = OCFS2_INODE_UPDATE_CREDITS;
1652  	unsigned int clusters_to_alloc, extents_to_split, clusters_need = 0;
1653  	struct ocfs2_write_ctxt *wc;
1654  	struct inode *inode = mapping->host;
1655  	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
1656  	struct ocfs2_dinode *di;
1657  	struct ocfs2_alloc_context *data_ac = NULL;
1658  	struct ocfs2_alloc_context *meta_ac = NULL;
1659  	handle_t *handle;
1660  	struct ocfs2_extent_tree et;
1661  	int try_free = 1, ret1;
1662  
1663  try_again:
1664  	ret = ocfs2_alloc_write_ctxt(&wc, osb, pos, len, type, di_bh);
1665  	if (ret) {
1666  		mlog_errno(ret);
1667  		return ret;
1668  	}
1669  
1670  	if (ocfs2_supports_inline_data(osb)) {
1671  		ret = ocfs2_try_to_write_inline_data(mapping, inode, pos, len,
1672  						     mmap_page, wc);
1673  		if (ret == 1) {
1674  			ret = 0;
1675  			goto success;
1676  		}
1677  		if (ret < 0) {
1678  			mlog_errno(ret);
1679  			goto out;
1680  		}
1681  	}
1682  
1683  	/* Direct io change i_size late, should not zero tail here. */
1684  	if (type != OCFS2_WRITE_DIRECT) {
1685  		if (ocfs2_sparse_alloc(osb))
1686  			ret = ocfs2_zero_tail(inode, di_bh, pos);
1687  		else
1688  			ret = ocfs2_expand_nonsparse_inode(inode, di_bh, pos,
1689  							   len, wc);
1690  		if (ret) {
1691  			mlog_errno(ret);
1692  			goto out;
1693  		}
1694  	}
1695  
1696  	ret = ocfs2_check_range_for_refcount(inode, pos, len);
1697  	if (ret < 0) {
1698  		mlog_errno(ret);
1699  		goto out;
1700  	} else if (ret == 1) {
1701  		clusters_need = wc->w_clen;
1702  		ret = ocfs2_refcount_cow(inode, di_bh,
1703  					 wc->w_cpos, wc->w_clen, UINT_MAX);
1704  		if (ret) {
1705  			mlog_errno(ret);
1706  			goto out;
1707  		}
1708  	}
1709  
1710  	ret = ocfs2_populate_write_desc(inode, wc, &clusters_to_alloc,
1711  					&extents_to_split);
1712  	if (ret) {
1713  		mlog_errno(ret);
1714  		goto out;
1715  	}
1716  	clusters_need += clusters_to_alloc;
1717  
1718  	di = (struct ocfs2_dinode *)wc->w_di_bh->b_data;
1719  
1720  	trace_ocfs2_write_begin_nolock(
1721  			(unsigned long long)OCFS2_I(inode)->ip_blkno,
1722  			(long long)i_size_read(inode),
1723  			le32_to_cpu(di->i_clusters),
1724  			pos, len, type, mmap_page,
1725  			clusters_to_alloc, extents_to_split);
1726  
1727  	/*
1728  	 * We set w_target_from, w_target_to here so that
1729  	 * ocfs2_write_end() knows which range in the target page to
1730  	 * write out. An allocation requires that we write the entire
1731  	 * cluster range.
1732  	 */
1733  	if (clusters_to_alloc || extents_to_split) {
1734  		/*
1735  		 * XXX: We are stretching the limits of
1736  		 * ocfs2_lock_allocators(). It greatly over-estimates
1737  		 * the work to be done.
1738  		 */
1739  		ocfs2_init_dinode_extent_tree(&et, INODE_CACHE(inode),
1740  					      wc->w_di_bh);
1741  		ret = ocfs2_lock_allocators(inode, &et,
1742  					    clusters_to_alloc, extents_to_split,
1743  					    &data_ac, &meta_ac);
1744  		if (ret) {
1745  			mlog_errno(ret);
1746  			goto out;
1747  		}
1748  
1749  		if (data_ac)
1750  			data_ac->ac_resv = &OCFS2_I(inode)->ip_la_data_resv;
1751  
1752  		credits = ocfs2_calc_extend_credits(inode->i_sb,
1753  						    &di->id2.i_list);
1754  	} else if (type == OCFS2_WRITE_DIRECT)
1755  		/* direct write needs not to start trans if no extents alloc. */
1756  		goto success;
1757  
1758  	/*
1759  	 * We have to zero sparse allocated clusters, unwritten extent clusters,
1760  	 * and non-sparse clusters we just extended.  For non-sparse writes,
1761  	 * we know zeros will only be needed in the first and/or last cluster.
1762  	 */
1763  	if (wc->w_clen && (wc->w_desc[0].c_needs_zero ||
1764  			   wc->w_desc[wc->w_clen - 1].c_needs_zero))
1765  		cluster_of_pages = 1;
1766  	else
1767  		cluster_of_pages = 0;
1768  
1769  	ocfs2_set_target_boundaries(osb, wc, pos, len, cluster_of_pages);
1770  
1771  	handle = ocfs2_start_trans(osb, credits);
1772  	if (IS_ERR(handle)) {
1773  		ret = PTR_ERR(handle);
1774  		mlog_errno(ret);
1775  		goto out;
1776  	}
1777  
1778  	wc->w_handle = handle;
1779  
1780  	if (clusters_to_alloc) {
1781  		ret = dquot_alloc_space_nodirty(inode,
1782  			ocfs2_clusters_to_bytes(osb->sb, clusters_to_alloc));
1783  		if (ret)
1784  			goto out_commit;
1785  	}
1786  
1787  	ret = ocfs2_journal_access_di(handle, INODE_CACHE(inode), wc->w_di_bh,
1788  				      OCFS2_JOURNAL_ACCESS_WRITE);
1789  	if (ret) {
1790  		mlog_errno(ret);
1791  		goto out_quota;
1792  	}
1793  
1794  	/*
1795  	 * Fill our page array first. That way we've grabbed enough so
1796  	 * that we can zero and flush if we error after adding the
1797  	 * extent.
1798  	 */
1799  	ret = ocfs2_grab_pages_for_write(mapping, wc, wc->w_cpos, pos, len,
1800  					 cluster_of_pages, mmap_page);
1801  	if (ret) {
1802  		/*
1803  		 * ocfs2_grab_pages_for_write() returns -EAGAIN if it could not lock
1804  		 * the target page. In this case, we exit with no error and no target
1805  		 * page. This will trigger the caller, page_mkwrite(), to re-try
1806  		 * the operation.
1807  		 */
1808  		if (type == OCFS2_WRITE_MMAP && ret == -EAGAIN) {
1809  			BUG_ON(wc->w_target_page);
1810  			ret = 0;
1811  			goto out_quota;
1812  		}
1813  
1814  		mlog_errno(ret);
1815  		goto out_quota;
1816  	}
1817  
1818  	ret = ocfs2_write_cluster_by_desc(mapping, data_ac, meta_ac, wc, pos,
1819  					  len);
1820  	if (ret) {
1821  		mlog_errno(ret);
1822  		goto out_quota;
1823  	}
1824  
1825  	if (data_ac)
1826  		ocfs2_free_alloc_context(data_ac);
1827  	if (meta_ac)
1828  		ocfs2_free_alloc_context(meta_ac);
1829  
1830  success:
1831  	if (pagep)
1832  		*pagep = wc->w_target_page;
1833  	*fsdata = wc;
1834  	return 0;
1835  out_quota:
1836  	if (clusters_to_alloc)
1837  		dquot_free_space(inode,
1838  			  ocfs2_clusters_to_bytes(osb->sb, clusters_to_alloc));
1839  out_commit:
1840  	ocfs2_commit_trans(osb, handle);
1841  
1842  out:
1843  	/*
1844  	 * The mmapped page won't be unlocked in ocfs2_free_write_ctxt(),
1845  	 * even in case of error here like ENOSPC and ENOMEM. So, we need
1846  	 * to unlock the target page manually to prevent deadlocks when
1847  	 * retrying again on ENOSPC, or when returning non-VM_FAULT_LOCKED
1848  	 * to VM code.
1849  	 */
1850  	if (wc->w_target_locked)
1851  		unlock_page(mmap_page);
1852  
1853  	ocfs2_free_write_ctxt(inode, wc);
1854  
1855  	if (data_ac) {
1856  		ocfs2_free_alloc_context(data_ac);
1857  		data_ac = NULL;
1858  	}
1859  	if (meta_ac) {
1860  		ocfs2_free_alloc_context(meta_ac);
1861  		meta_ac = NULL;
1862  	}
1863  
1864  	if (ret == -ENOSPC && try_free) {
1865  		/*
1866  		 * Try to free some truncate log so that we can have enough
1867  		 * clusters to allocate.
1868  		 */
1869  		try_free = 0;
1870  
1871  		ret1 = ocfs2_try_to_free_truncate_log(osb, clusters_need);
1872  		if (ret1 == 1)
1873  			goto try_again;
1874  
1875  		if (ret1 < 0)
1876  			mlog_errno(ret1);
1877  	}
1878  
1879  	return ret;
1880  }
1881  
1882  static int ocfs2_write_begin(struct file *file, struct address_space *mapping,
1883  			     loff_t pos, unsigned len,
1884  			     struct page **pagep, void **fsdata)
1885  {
1886  	int ret;
1887  	struct buffer_head *di_bh = NULL;
1888  	struct inode *inode = mapping->host;
1889  
1890  	ret = ocfs2_inode_lock(inode, &di_bh, 1);
1891  	if (ret) {
1892  		mlog_errno(ret);
1893  		return ret;
1894  	}
1895  
1896  	/*
1897  	 * Take alloc sem here to prevent concurrent lookups. That way
1898  	 * the mapping, zeroing and tree manipulation within
1899  	 * ocfs2_write() will be safe against ->read_folio(). This
1900  	 * should also serve to lock out allocation from a shared
1901  	 * writeable region.
1902  	 */
1903  	down_write(&OCFS2_I(inode)->ip_alloc_sem);
1904  
1905  	ret = ocfs2_write_begin_nolock(mapping, pos, len, OCFS2_WRITE_BUFFER,
1906  				       pagep, fsdata, di_bh, NULL);
1907  	if (ret) {
1908  		mlog_errno(ret);
1909  		goto out_fail;
1910  	}
1911  
1912  	brelse(di_bh);
1913  
1914  	return 0;
1915  
1916  out_fail:
1917  	up_write(&OCFS2_I(inode)->ip_alloc_sem);
1918  
1919  	brelse(di_bh);
1920  	ocfs2_inode_unlock(inode, 1);
1921  
1922  	return ret;
1923  }
1924  
1925  static void ocfs2_write_end_inline(struct inode *inode, loff_t pos,
1926  				   unsigned len, unsigned *copied,
1927  				   struct ocfs2_dinode *di,
1928  				   struct ocfs2_write_ctxt *wc)
1929  {
1930  	void *kaddr;
1931  
1932  	if (unlikely(*copied < len)) {
1933  		if (!PageUptodate(wc->w_target_page)) {
1934  			*copied = 0;
1935  			return;
1936  		}
1937  	}
1938  
1939  	kaddr = kmap_atomic(wc->w_target_page);
1940  	memcpy(di->id2.i_data.id_data + pos, kaddr + pos, *copied);
1941  	kunmap_atomic(kaddr);
1942  
1943  	trace_ocfs2_write_end_inline(
1944  	     (unsigned long long)OCFS2_I(inode)->ip_blkno,
1945  	     (unsigned long long)pos, *copied,
1946  	     le16_to_cpu(di->id2.i_data.id_count),
1947  	     le16_to_cpu(di->i_dyn_features));
1948  }
1949  
1950  int ocfs2_write_end_nolock(struct address_space *mapping,
1951  			   loff_t pos, unsigned len, unsigned copied, void *fsdata)
1952  {
1953  	int i, ret;
1954  	unsigned from, to, start = pos & (PAGE_SIZE - 1);
1955  	struct inode *inode = mapping->host;
1956  	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
1957  	struct ocfs2_write_ctxt *wc = fsdata;
1958  	struct ocfs2_dinode *di = (struct ocfs2_dinode *)wc->w_di_bh->b_data;
1959  	handle_t *handle = wc->w_handle;
1960  	struct page *tmppage;
1961  
1962  	BUG_ON(!list_empty(&wc->w_unwritten_list));
1963  
1964  	if (handle) {
1965  		ret = ocfs2_journal_access_di(handle, INODE_CACHE(inode),
1966  				wc->w_di_bh, OCFS2_JOURNAL_ACCESS_WRITE);
1967  		if (ret) {
1968  			copied = ret;
1969  			mlog_errno(ret);
1970  			goto out;
1971  		}
1972  	}
1973  
1974  	if (OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL) {
1975  		ocfs2_write_end_inline(inode, pos, len, &copied, di, wc);
1976  		goto out_write_size;
1977  	}
1978  
1979  	if (unlikely(copied < len) && wc->w_target_page) {
1980  		if (!PageUptodate(wc->w_target_page))
1981  			copied = 0;
1982  
1983  		ocfs2_zero_new_buffers(wc->w_target_page, start+copied,
1984  				       start+len);
1985  	}
1986  	if (wc->w_target_page)
1987  		flush_dcache_page(wc->w_target_page);
1988  
1989  	for(i = 0; i < wc->w_num_pages; i++) {
1990  		tmppage = wc->w_pages[i];
1991  
1992  		/* This is the direct io target page. */
1993  		if (tmppage == NULL)
1994  			continue;
1995  
1996  		if (tmppage == wc->w_target_page) {
1997  			from = wc->w_target_from;
1998  			to = wc->w_target_to;
1999  
2000  			BUG_ON(from > PAGE_SIZE ||
2001  			       to > PAGE_SIZE ||
2002  			       to < from);
2003  		} else {
2004  			/*
2005  			 * Pages adjacent to the target (if any) imply
2006  			 * a hole-filling write in which case we want
2007  			 * to flush their entire range.
2008  			 */
2009  			from = 0;
2010  			to = PAGE_SIZE;
2011  		}
2012  
2013  		if (page_has_buffers(tmppage)) {
2014  			if (handle && ocfs2_should_order_data(inode)) {
2015  				loff_t start_byte =
2016  					((loff_t)tmppage->index << PAGE_SHIFT) +
2017  					from;
2018  				loff_t length = to - from;
2019  				ocfs2_jbd2_inode_add_write(handle, inode,
2020  							   start_byte, length);
2021  			}
2022  			block_commit_write(tmppage, from, to);
2023  		}
2024  	}
2025  
2026  out_write_size:
2027  	/* Direct io do not update i_size here. */
2028  	if (wc->w_type != OCFS2_WRITE_DIRECT) {
2029  		pos += copied;
2030  		if (pos > i_size_read(inode)) {
2031  			i_size_write(inode, pos);
2032  			mark_inode_dirty(inode);
2033  		}
2034  		inode->i_blocks = ocfs2_inode_sector_count(inode);
2035  		di->i_size = cpu_to_le64((u64)i_size_read(inode));
2036  		inode->i_mtime = inode->i_ctime = current_time(inode);
2037  		di->i_mtime = di->i_ctime = cpu_to_le64(inode->i_mtime.tv_sec);
2038  		di->i_mtime_nsec = di->i_ctime_nsec = cpu_to_le32(inode->i_mtime.tv_nsec);
2039  		if (handle)
2040  			ocfs2_update_inode_fsync_trans(handle, inode, 1);
2041  	}
2042  	if (handle)
2043  		ocfs2_journal_dirty(handle, wc->w_di_bh);
2044  
2045  out:
2046  	/* unlock pages before dealloc since it needs acquiring j_trans_barrier
2047  	 * lock, or it will cause a deadlock since journal commit threads holds
2048  	 * this lock and will ask for the page lock when flushing the data.
2049  	 * put it here to preserve the unlock order.
2050  	 */
2051  	ocfs2_unlock_pages(wc);
2052  
2053  	if (handle)
2054  		ocfs2_commit_trans(osb, handle);
2055  
2056  	ocfs2_run_deallocs(osb, &wc->w_dealloc);
2057  
2058  	brelse(wc->w_di_bh);
2059  	kfree(wc);
2060  
2061  	return copied;
2062  }
2063  
2064  static int ocfs2_write_end(struct file *file, struct address_space *mapping,
2065  			   loff_t pos, unsigned len, unsigned copied,
2066  			   struct page *page, void *fsdata)
2067  {
2068  	int ret;
2069  	struct inode *inode = mapping->host;
2070  
2071  	ret = ocfs2_write_end_nolock(mapping, pos, len, copied, fsdata);
2072  
2073  	up_write(&OCFS2_I(inode)->ip_alloc_sem);
2074  	ocfs2_inode_unlock(inode, 1);
2075  
2076  	return ret;
2077  }
2078  
2079  struct ocfs2_dio_write_ctxt {
2080  	struct list_head	dw_zero_list;
2081  	unsigned		dw_zero_count;
2082  	int			dw_orphaned;
2083  	pid_t			dw_writer_pid;
2084  };
2085  
2086  static struct ocfs2_dio_write_ctxt *
2087  ocfs2_dio_alloc_write_ctx(struct buffer_head *bh, int *alloc)
2088  {
2089  	struct ocfs2_dio_write_ctxt *dwc = NULL;
2090  
2091  	if (bh->b_private)
2092  		return bh->b_private;
2093  
2094  	dwc = kmalloc(sizeof(struct ocfs2_dio_write_ctxt), GFP_NOFS);
2095  	if (dwc == NULL)
2096  		return NULL;
2097  	INIT_LIST_HEAD(&dwc->dw_zero_list);
2098  	dwc->dw_zero_count = 0;
2099  	dwc->dw_orphaned = 0;
2100  	dwc->dw_writer_pid = task_pid_nr(current);
2101  	bh->b_private = dwc;
2102  	*alloc = 1;
2103  
2104  	return dwc;
2105  }
2106  
2107  static void ocfs2_dio_free_write_ctx(struct inode *inode,
2108  				     struct ocfs2_dio_write_ctxt *dwc)
2109  {
2110  	ocfs2_free_unwritten_list(inode, &dwc->dw_zero_list);
2111  	kfree(dwc);
2112  }
2113  
2114  /*
2115   * TODO: Make this into a generic get_blocks function.
2116   *
2117   * From do_direct_io in direct-io.c:
2118   *  "So what we do is to permit the ->get_blocks function to populate
2119   *   bh.b_size with the size of IO which is permitted at this offset and
2120   *   this i_blkbits."
2121   *
2122   * This function is called directly from get_more_blocks in direct-io.c.
2123   *
2124   * called like this: dio->get_blocks(dio->inode, fs_startblk,
2125   * 					fs_count, map_bh, dio->rw == WRITE);
2126   */
2127  static int ocfs2_dio_wr_get_block(struct inode *inode, sector_t iblock,
2128  			       struct buffer_head *bh_result, int create)
2129  {
2130  	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
2131  	struct ocfs2_inode_info *oi = OCFS2_I(inode);
2132  	struct ocfs2_write_ctxt *wc;
2133  	struct ocfs2_write_cluster_desc *desc = NULL;
2134  	struct ocfs2_dio_write_ctxt *dwc = NULL;
2135  	struct buffer_head *di_bh = NULL;
2136  	u64 p_blkno;
2137  	unsigned int i_blkbits = inode->i_sb->s_blocksize_bits;
2138  	loff_t pos = iblock << i_blkbits;
2139  	sector_t endblk = (i_size_read(inode) - 1) >> i_blkbits;
2140  	unsigned len, total_len = bh_result->b_size;
2141  	int ret = 0, first_get_block = 0;
2142  
2143  	len = osb->s_clustersize - (pos & (osb->s_clustersize - 1));
2144  	len = min(total_len, len);
2145  
2146  	/*
2147  	 * bh_result->b_size is count in get_more_blocks according to write
2148  	 * "pos" and "end", we need map twice to return different buffer state:
2149  	 * 1. area in file size, not set NEW;
2150  	 * 2. area out file size, set  NEW.
2151  	 *
2152  	 *		   iblock    endblk
2153  	 * |--------|---------|---------|---------
2154  	 * |<-------area in file------->|
2155  	 */
2156  
2157  	if ((iblock <= endblk) &&
2158  	    ((iblock + ((len - 1) >> i_blkbits)) > endblk))
2159  		len = (endblk - iblock + 1) << i_blkbits;
2160  
2161  	mlog(0, "get block of %lu at %llu:%u req %u\n",
2162  			inode->i_ino, pos, len, total_len);
2163  
2164  	/*
2165  	 * Because we need to change file size in ocfs2_dio_end_io_write(), or
2166  	 * we may need to add it to orphan dir. So can not fall to fast path
2167  	 * while file size will be changed.
2168  	 */
2169  	if (pos + total_len <= i_size_read(inode)) {
2170  
2171  		/* This is the fast path for re-write. */
2172  		ret = ocfs2_lock_get_block(inode, iblock, bh_result, create);
2173  		if (buffer_mapped(bh_result) &&
2174  		    !buffer_new(bh_result) &&
2175  		    ret == 0)
2176  			goto out;
2177  
2178  		/* Clear state set by ocfs2_get_block. */
2179  		bh_result->b_state = 0;
2180  	}
2181  
2182  	dwc = ocfs2_dio_alloc_write_ctx(bh_result, &first_get_block);
2183  	if (unlikely(dwc == NULL)) {
2184  		ret = -ENOMEM;
2185  		mlog_errno(ret);
2186  		goto out;
2187  	}
2188  
2189  	if (ocfs2_clusters_for_bytes(inode->i_sb, pos + total_len) >
2190  	    ocfs2_clusters_for_bytes(inode->i_sb, i_size_read(inode)) &&
2191  	    !dwc->dw_orphaned) {
2192  		/*
2193  		 * when we are going to alloc extents beyond file size, add the
2194  		 * inode to orphan dir, so we can recall those spaces when
2195  		 * system crashed during write.
2196  		 */
2197  		ret = ocfs2_add_inode_to_orphan(osb, inode);
2198  		if (ret < 0) {
2199  			mlog_errno(ret);
2200  			goto out;
2201  		}
2202  		dwc->dw_orphaned = 1;
2203  	}
2204  
2205  	ret = ocfs2_inode_lock(inode, &di_bh, 1);
2206  	if (ret) {
2207  		mlog_errno(ret);
2208  		goto out;
2209  	}
2210  
2211  	down_write(&oi->ip_alloc_sem);
2212  
2213  	if (first_get_block) {
2214  		if (ocfs2_sparse_alloc(osb))
2215  			ret = ocfs2_zero_tail(inode, di_bh, pos);
2216  		else
2217  			ret = ocfs2_expand_nonsparse_inode(inode, di_bh, pos,
2218  							   total_len, NULL);
2219  		if (ret < 0) {
2220  			mlog_errno(ret);
2221  			goto unlock;
2222  		}
2223  	}
2224  
2225  	ret = ocfs2_write_begin_nolock(inode->i_mapping, pos, len,
2226  				       OCFS2_WRITE_DIRECT, NULL,
2227  				       (void **)&wc, di_bh, NULL);
2228  	if (ret) {
2229  		mlog_errno(ret);
2230  		goto unlock;
2231  	}
2232  
2233  	desc = &wc->w_desc[0];
2234  
2235  	p_blkno = ocfs2_clusters_to_blocks(inode->i_sb, desc->c_phys);
2236  	BUG_ON(p_blkno == 0);
2237  	p_blkno += iblock & (u64)(ocfs2_clusters_to_blocks(inode->i_sb, 1) - 1);
2238  
2239  	map_bh(bh_result, inode->i_sb, p_blkno);
2240  	bh_result->b_size = len;
2241  	if (desc->c_needs_zero)
2242  		set_buffer_new(bh_result);
2243  
2244  	if (iblock > endblk)
2245  		set_buffer_new(bh_result);
2246  
2247  	/* May sleep in end_io. It should not happen in a irq context. So defer
2248  	 * it to dio work queue. */
2249  	set_buffer_defer_completion(bh_result);
2250  
2251  	if (!list_empty(&wc->w_unwritten_list)) {
2252  		struct ocfs2_unwritten_extent *ue = NULL;
2253  
2254  		ue = list_first_entry(&wc->w_unwritten_list,
2255  				      struct ocfs2_unwritten_extent,
2256  				      ue_node);
2257  		BUG_ON(ue->ue_cpos != desc->c_cpos);
2258  		/* The physical address may be 0, fill it. */
2259  		ue->ue_phys = desc->c_phys;
2260  
2261  		list_splice_tail_init(&wc->w_unwritten_list, &dwc->dw_zero_list);
2262  		dwc->dw_zero_count += wc->w_unwritten_count;
2263  	}
2264  
2265  	ret = ocfs2_write_end_nolock(inode->i_mapping, pos, len, len, wc);
2266  	BUG_ON(ret != len);
2267  	ret = 0;
2268  unlock:
2269  	up_write(&oi->ip_alloc_sem);
2270  	ocfs2_inode_unlock(inode, 1);
2271  	brelse(di_bh);
2272  out:
2273  	if (ret < 0)
2274  		ret = -EIO;
2275  	return ret;
2276  }
2277  
2278  static int ocfs2_dio_end_io_write(struct inode *inode,
2279  				  struct ocfs2_dio_write_ctxt *dwc,
2280  				  loff_t offset,
2281  				  ssize_t bytes)
2282  {
2283  	struct ocfs2_cached_dealloc_ctxt dealloc;
2284  	struct ocfs2_extent_tree et;
2285  	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
2286  	struct ocfs2_inode_info *oi = OCFS2_I(inode);
2287  	struct ocfs2_unwritten_extent *ue = NULL;
2288  	struct buffer_head *di_bh = NULL;
2289  	struct ocfs2_dinode *di;
2290  	struct ocfs2_alloc_context *data_ac = NULL;
2291  	struct ocfs2_alloc_context *meta_ac = NULL;
2292  	handle_t *handle = NULL;
2293  	loff_t end = offset + bytes;
2294  	int ret = 0, credits = 0;
2295  
2296  	ocfs2_init_dealloc_ctxt(&dealloc);
2297  
2298  	/* We do clear unwritten, delete orphan, change i_size here. If neither
2299  	 * of these happen, we can skip all this. */
2300  	if (list_empty(&dwc->dw_zero_list) &&
2301  	    end <= i_size_read(inode) &&
2302  	    !dwc->dw_orphaned)
2303  		goto out;
2304  
2305  	ret = ocfs2_inode_lock(inode, &di_bh, 1);
2306  	if (ret < 0) {
2307  		mlog_errno(ret);
2308  		goto out;
2309  	}
2310  
2311  	down_write(&oi->ip_alloc_sem);
2312  
2313  	/* Delete orphan before acquire i_rwsem. */
2314  	if (dwc->dw_orphaned) {
2315  		BUG_ON(dwc->dw_writer_pid != task_pid_nr(current));
2316  
2317  		end = end > i_size_read(inode) ? end : 0;
2318  
2319  		ret = ocfs2_del_inode_from_orphan(osb, inode, di_bh,
2320  				!!end, end);
2321  		if (ret < 0)
2322  			mlog_errno(ret);
2323  	}
2324  
2325  	di = (struct ocfs2_dinode *)di_bh->b_data;
2326  
2327  	ocfs2_init_dinode_extent_tree(&et, INODE_CACHE(inode), di_bh);
2328  
2329  	/* Attach dealloc with extent tree in case that we may reuse extents
2330  	 * which are already unlinked from current extent tree due to extent
2331  	 * rotation and merging.
2332  	 */
2333  	et.et_dealloc = &dealloc;
2334  
2335  	ret = ocfs2_lock_allocators(inode, &et, 0, dwc->dw_zero_count*2,
2336  				    &data_ac, &meta_ac);
2337  	if (ret) {
2338  		mlog_errno(ret);
2339  		goto unlock;
2340  	}
2341  
2342  	credits = ocfs2_calc_extend_credits(inode->i_sb, &di->id2.i_list);
2343  
2344  	handle = ocfs2_start_trans(osb, credits);
2345  	if (IS_ERR(handle)) {
2346  		ret = PTR_ERR(handle);
2347  		mlog_errno(ret);
2348  		goto unlock;
2349  	}
2350  	ret = ocfs2_journal_access_di(handle, INODE_CACHE(inode), di_bh,
2351  				      OCFS2_JOURNAL_ACCESS_WRITE);
2352  	if (ret) {
2353  		mlog_errno(ret);
2354  		goto commit;
2355  	}
2356  
2357  	list_for_each_entry(ue, &dwc->dw_zero_list, ue_node) {
2358  		ret = ocfs2_mark_extent_written(inode, &et, handle,
2359  						ue->ue_cpos, 1,
2360  						ue->ue_phys,
2361  						meta_ac, &dealloc);
2362  		if (ret < 0) {
2363  			mlog_errno(ret);
2364  			break;
2365  		}
2366  	}
2367  
2368  	if (end > i_size_read(inode)) {
2369  		ret = ocfs2_set_inode_size(handle, inode, di_bh, end);
2370  		if (ret < 0)
2371  			mlog_errno(ret);
2372  	}
2373  commit:
2374  	ocfs2_commit_trans(osb, handle);
2375  unlock:
2376  	up_write(&oi->ip_alloc_sem);
2377  	ocfs2_inode_unlock(inode, 1);
2378  	brelse(di_bh);
2379  out:
2380  	if (data_ac)
2381  		ocfs2_free_alloc_context(data_ac);
2382  	if (meta_ac)
2383  		ocfs2_free_alloc_context(meta_ac);
2384  	ocfs2_run_deallocs(osb, &dealloc);
2385  	ocfs2_dio_free_write_ctx(inode, dwc);
2386  
2387  	return ret;
2388  }
2389  
2390  /*
2391   * ocfs2_dio_end_io is called by the dio core when a dio is finished.  We're
2392   * particularly interested in the aio/dio case.  We use the rw_lock DLM lock
2393   * to protect io on one node from truncation on another.
2394   */
2395  static int ocfs2_dio_end_io(struct kiocb *iocb,
2396  			    loff_t offset,
2397  			    ssize_t bytes,
2398  			    void *private)
2399  {
2400  	struct inode *inode = file_inode(iocb->ki_filp);
2401  	int level;
2402  	int ret = 0;
2403  
2404  	/* this io's submitter should not have unlocked this before we could */
2405  	BUG_ON(!ocfs2_iocb_is_rw_locked(iocb));
2406  
2407  	if (bytes <= 0)
2408  		mlog_ratelimited(ML_ERROR, "Direct IO failed, bytes = %lld",
2409  				 (long long)bytes);
2410  	if (private) {
2411  		if (bytes > 0)
2412  			ret = ocfs2_dio_end_io_write(inode, private, offset,
2413  						     bytes);
2414  		else
2415  			ocfs2_dio_free_write_ctx(inode, private);
2416  	}
2417  
2418  	ocfs2_iocb_clear_rw_locked(iocb);
2419  
2420  	level = ocfs2_iocb_rw_locked_level(iocb);
2421  	ocfs2_rw_unlock(inode, level);
2422  	return ret;
2423  }
2424  
2425  static ssize_t ocfs2_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
2426  {
2427  	struct file *file = iocb->ki_filp;
2428  	struct inode *inode = file->f_mapping->host;
2429  	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
2430  	get_block_t *get_block;
2431  
2432  	/*
2433  	 * Fallback to buffered I/O if we see an inode without
2434  	 * extents.
2435  	 */
2436  	if (OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL)
2437  		return 0;
2438  
2439  	/* Fallback to buffered I/O if we do not support append dio. */
2440  	if (iocb->ki_pos + iter->count > i_size_read(inode) &&
2441  	    !ocfs2_supports_append_dio(osb))
2442  		return 0;
2443  
2444  	if (iov_iter_rw(iter) == READ)
2445  		get_block = ocfs2_lock_get_block;
2446  	else
2447  		get_block = ocfs2_dio_wr_get_block;
2448  
2449  	return __blockdev_direct_IO(iocb, inode, inode->i_sb->s_bdev,
2450  				    iter, get_block,
2451  				    ocfs2_dio_end_io, NULL, 0);
2452  }
2453  
2454  const struct address_space_operations ocfs2_aops = {
2455  	.dirty_folio		= block_dirty_folio,
2456  	.read_folio		= ocfs2_read_folio,
2457  	.readahead		= ocfs2_readahead,
2458  	.writepage		= ocfs2_writepage,
2459  	.write_begin		= ocfs2_write_begin,
2460  	.write_end		= ocfs2_write_end,
2461  	.bmap			= ocfs2_bmap,
2462  	.direct_IO		= ocfs2_direct_IO,
2463  	.invalidate_folio	= block_invalidate_folio,
2464  	.release_folio		= ocfs2_release_folio,
2465  	.migrate_folio		= buffer_migrate_folio,
2466  	.is_partially_uptodate	= block_is_partially_uptodate,
2467  	.error_remove_page	= generic_error_remove_page,
2468  };
2469