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Linux/fs/ocfs2/aops.c

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  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 #include <linux/blkdev.h>
 32 #include <linux/uio.h>
 33 
 34 #include <cluster/masklog.h>
 35 
 36 #include "ocfs2.h"
 37 
 38 #include "alloc.h"
 39 #include "aops.h"
 40 #include "dlmglue.h"
 41 #include "extent_map.h"
 42 #include "file.h"
 43 #include "inode.h"
 44 #include "journal.h"
 45 #include "suballoc.h"
 46 #include "super.h"
 47 #include "symlink.h"
 48 #include "refcounttree.h"
 49 #include "ocfs2_trace.h"
 50 
 51 #include "buffer_head_io.h"
 52 #include "dir.h"
 53 #include "namei.h"
 54 #include "sysfile.h"
 55 
 56 static int ocfs2_symlink_get_block(struct inode *inode, sector_t iblock,
 57                                    struct buffer_head *bh_result, int create)
 58 {
 59         int err = -EIO;
 60         int status;
 61         struct ocfs2_dinode *fe = NULL;
 62         struct buffer_head *bh = NULL;
 63         struct buffer_head *buffer_cache_bh = NULL;
 64         struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
 65         void *kaddr;
 66 
 67         trace_ocfs2_symlink_get_block(
 68                         (unsigned long long)OCFS2_I(inode)->ip_blkno,
 69                         (unsigned long long)iblock, bh_result, create);
 70 
 71         BUG_ON(ocfs2_inode_is_fast_symlink(inode));
 72 
 73         if ((iblock << inode->i_sb->s_blocksize_bits) > PATH_MAX + 1) {
 74                 mlog(ML_ERROR, "block offset > PATH_MAX: %llu",
 75                      (unsigned long long)iblock);
 76                 goto bail;
 77         }
 78 
 79         status = ocfs2_read_inode_block(inode, &bh);
 80         if (status < 0) {
 81                 mlog_errno(status);
 82                 goto bail;
 83         }
 84         fe = (struct ocfs2_dinode *) bh->b_data;
 85 
 86         if ((u64)iblock >= ocfs2_clusters_to_blocks(inode->i_sb,
 87                                                     le32_to_cpu(fe->i_clusters))) {
 88                 err = -ENOMEM;
 89                 mlog(ML_ERROR, "block offset is outside the allocated size: "
 90                      "%llu\n", (unsigned long long)iblock);
 91                 goto bail;
 92         }
 93 
 94         /* We don't use the page cache to create symlink data, so if
 95          * need be, copy it over from the buffer cache. */
 96         if (!buffer_uptodate(bh_result) && ocfs2_inode_is_new(inode)) {
 97                 u64 blkno = le64_to_cpu(fe->id2.i_list.l_recs[0].e_blkno) +
 98                             iblock;
 99                 buffer_cache_bh = sb_getblk(osb->sb, blkno);
100                 if (!buffer_cache_bh) {
101                         err = -ENOMEM;
102                         mlog(ML_ERROR, "couldn't getblock for symlink!\n");
103                         goto bail;
104                 }
105 
106                 /* we haven't locked out transactions, so a commit
107                  * could've happened. Since we've got a reference on
108                  * the bh, even if it commits while we're doing the
109                  * copy, the data is still good. */
110                 if (buffer_jbd(buffer_cache_bh)
111                     && ocfs2_inode_is_new(inode)) {
112                         kaddr = kmap_atomic(bh_result->b_page);
113                         if (!kaddr) {
114                                 mlog(ML_ERROR, "couldn't kmap!\n");
115                                 goto bail;
116                         }
117                         memcpy(kaddr + (bh_result->b_size * iblock),
118                                buffer_cache_bh->b_data,
119                                bh_result->b_size);
120                         kunmap_atomic(kaddr);
121                         set_buffer_uptodate(bh_result);
122                 }
123                 brelse(buffer_cache_bh);
124         }
125 
126         map_bh(bh_result, inode->i_sb,
127                le64_to_cpu(fe->id2.i_list.l_recs[0].e_blkno) + iblock);
128 
129         err = 0;
130 
131 bail:
132         brelse(bh);
133 
134         return err;
135 }
136 
137 int ocfs2_get_block(struct inode *inode, sector_t iblock,
138                     struct buffer_head *bh_result, int create)
139 {
140         int err = 0;
141         unsigned int ext_flags;
142         u64 max_blocks = bh_result->b_size >> inode->i_blkbits;
143         u64 p_blkno, count, past_eof;
144         struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
145 
146         trace_ocfs2_get_block((unsigned long long)OCFS2_I(inode)->ip_blkno,
147                               (unsigned long long)iblock, bh_result, create);
148 
149         if (OCFS2_I(inode)->ip_flags & OCFS2_INODE_SYSTEM_FILE)
150                 mlog(ML_NOTICE, "get_block on system inode 0x%p (%lu)\n",
151                      inode, inode->i_ino);
152 
153         if (S_ISLNK(inode->i_mode)) {
154                 /* this always does I/O for some reason. */
155                 err = ocfs2_symlink_get_block(inode, iblock, bh_result, create);
156                 goto bail;
157         }
158 
159         err = ocfs2_extent_map_get_blocks(inode, iblock, &p_blkno, &count,
160                                           &ext_flags);
161         if (err) {
162                 mlog(ML_ERROR, "Error %d from get_blocks(0x%p, %llu, 1, "
163                      "%llu, NULL)\n", err, inode, (unsigned long long)iblock,
164                      (unsigned long long)p_blkno);
165                 goto bail;
166         }
167 
168         if (max_blocks < count)
169                 count = max_blocks;
170 
171         /*
172          * ocfs2 never allocates in this function - the only time we
173          * need to use BH_New is when we're extending i_size on a file
174          * system which doesn't support holes, in which case BH_New
175          * allows __block_write_begin() to zero.
176          *
177          * If we see this on a sparse file system, then a truncate has
178          * raced us and removed the cluster. In this case, we clear
179          * the buffers dirty and uptodate bits and let the buffer code
180          * ignore it as a hole.
181          */
182         if (create && p_blkno == 0 && ocfs2_sparse_alloc(osb)) {
183                 clear_buffer_dirty(bh_result);
184                 clear_buffer_uptodate(bh_result);
185                 goto bail;
186         }
187 
188         /* Treat the unwritten extent as a hole for zeroing purposes. */
189         if (p_blkno && !(ext_flags & OCFS2_EXT_UNWRITTEN))
190                 map_bh(bh_result, inode->i_sb, p_blkno);
191 
192         bh_result->b_size = count << inode->i_blkbits;
193 
194         if (!ocfs2_sparse_alloc(osb)) {
195                 if (p_blkno == 0) {
196                         err = -EIO;
197                         mlog(ML_ERROR,
198                              "iblock = %llu p_blkno = %llu blkno=(%llu)\n",
199                              (unsigned long long)iblock,
200                              (unsigned long long)p_blkno,
201                              (unsigned long long)OCFS2_I(inode)->ip_blkno);
202                         mlog(ML_ERROR, "Size %llu, clusters %u\n", (unsigned long long)i_size_read(inode), OCFS2_I(inode)->ip_clusters);
203                         dump_stack();
204                         goto bail;
205                 }
206         }
207 
208         past_eof = ocfs2_blocks_for_bytes(inode->i_sb, i_size_read(inode));
209 
210         trace_ocfs2_get_block_end((unsigned long long)OCFS2_I(inode)->ip_blkno,
211                                   (unsigned long long)past_eof);
212         if (create && (iblock >= past_eof))
213                 set_buffer_new(bh_result);
214 
215 bail:
216         if (err < 0)
217                 err = -EIO;
218 
219         return err;
220 }
221 
222 int ocfs2_read_inline_data(struct inode *inode, struct page *page,
223                            struct buffer_head *di_bh)
224 {
225         void *kaddr;
226         loff_t size;
227         struct ocfs2_dinode *di = (struct ocfs2_dinode *)di_bh->b_data;
228 
229         if (!(le16_to_cpu(di->i_dyn_features) & OCFS2_INLINE_DATA_FL)) {
230                 ocfs2_error(inode->i_sb, "Inode %llu lost inline data flag\n",
231                             (unsigned long long)OCFS2_I(inode)->ip_blkno);
232                 return -EROFS;
233         }
234 
235         size = i_size_read(inode);
236 
237         if (size > PAGE_SIZE ||
238             size > ocfs2_max_inline_data_with_xattr(inode->i_sb, di)) {
239                 ocfs2_error(inode->i_sb,
240                             "Inode %llu has with inline data has bad size: %Lu\n",
241                             (unsigned long long)OCFS2_I(inode)->ip_blkno,
242                             (unsigned long long)size);
243                 return -EROFS;
244         }
245 
246         kaddr = kmap_atomic(page);
247         if (size)
248                 memcpy(kaddr, di->id2.i_data.id_data, size);
249         /* Clear the remaining part of the page */
250         memset(kaddr + size, 0, PAGE_SIZE - size);
251         flush_dcache_page(page);
252         kunmap_atomic(kaddr);
253 
254         SetPageUptodate(page);
255 
256         return 0;
257 }
258 
259 static int ocfs2_readpage_inline(struct inode *inode, struct page *page)
260 {
261         int ret;
262         struct buffer_head *di_bh = NULL;
263 
264         BUG_ON(!PageLocked(page));
265         BUG_ON(!(OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL));
266 
267         ret = ocfs2_read_inode_block(inode, &di_bh);
268         if (ret) {
269                 mlog_errno(ret);
270                 goto out;
271         }
272 
273         ret = ocfs2_read_inline_data(inode, page, di_bh);
274 out:
275         unlock_page(page);
276 
277         brelse(di_bh);
278         return ret;
279 }
280 
281 static int ocfs2_readpage(struct file *file, struct page *page)
282 {
283         struct inode *inode = page->mapping->host;
284         struct ocfs2_inode_info *oi = OCFS2_I(inode);
285         loff_t start = (loff_t)page->index << PAGE_SHIFT;
286         int ret, unlock = 1;
287 
288         trace_ocfs2_readpage((unsigned long long)oi->ip_blkno,
289                              (page ? page->index : 0));
290 
291         ret = ocfs2_inode_lock_with_page(inode, NULL, 0, page);
292         if (ret != 0) {
293                 if (ret == AOP_TRUNCATED_PAGE)
294                         unlock = 0;
295                 mlog_errno(ret);
296                 goto out;
297         }
298 
299         if (down_read_trylock(&oi->ip_alloc_sem) == 0) {
300                 /*
301                  * Unlock the page and cycle ip_alloc_sem so that we don't
302                  * busyloop waiting for ip_alloc_sem to unlock
303                  */
304                 ret = AOP_TRUNCATED_PAGE;
305                 unlock_page(page);
306                 unlock = 0;
307                 down_read(&oi->ip_alloc_sem);
308                 up_read(&oi->ip_alloc_sem);
309                 goto out_inode_unlock;
310         }
311 
312         /*
313          * i_size might have just been updated as we grabed the meta lock.  We
314          * might now be discovering a truncate that hit on another node.
315          * block_read_full_page->get_block freaks out if it is asked to read
316          * beyond the end of a file, so we check here.  Callers
317          * (generic_file_read, vm_ops->fault) are clever enough to check i_size
318          * and notice that the page they just read isn't needed.
319          *
320          * XXX sys_readahead() seems to get that wrong?
321          */
322         if (start >= i_size_read(inode)) {
323                 zero_user(page, 0, PAGE_SIZE);
324                 SetPageUptodate(page);
325                 ret = 0;
326                 goto out_alloc;
327         }
328 
329         if (oi->ip_dyn_features & OCFS2_INLINE_DATA_FL)
330                 ret = ocfs2_readpage_inline(inode, page);
331         else
332                 ret = block_read_full_page(page, ocfs2_get_block);
333         unlock = 0;
334 
335 out_alloc:
336         up_read(&OCFS2_I(inode)->ip_alloc_sem);
337 out_inode_unlock:
338         ocfs2_inode_unlock(inode, 0);
339 out:
340         if (unlock)
341                 unlock_page(page);
342         return ret;
343 }
344 
345 /*
346  * This is used only for read-ahead. Failures or difficult to handle
347  * situations are safe to ignore.
348  *
349  * Right now, we don't bother with BH_Boundary - in-inode extent lists
350  * are quite large (243 extents on 4k blocks), so most inodes don't
351  * grow out to a tree. If need be, detecting boundary extents could
352  * trivially be added in a future version of ocfs2_get_block().
353  */
354 static int ocfs2_readpages(struct file *filp, struct address_space *mapping,
355                            struct list_head *pages, unsigned nr_pages)
356 {
357         int ret, err = -EIO;
358         struct inode *inode = mapping->host;
359         struct ocfs2_inode_info *oi = OCFS2_I(inode);
360         loff_t start;
361         struct page *last;
362 
363         /*
364          * Use the nonblocking flag for the dlm code to avoid page
365          * lock inversion, but don't bother with retrying.
366          */
367         ret = ocfs2_inode_lock_full(inode, NULL, 0, OCFS2_LOCK_NONBLOCK);
368         if (ret)
369                 return err;
370 
371         if (down_read_trylock(&oi->ip_alloc_sem) == 0) {
372                 ocfs2_inode_unlock(inode, 0);
373                 return err;
374         }
375 
376         /*
377          * Don't bother with inline-data. There isn't anything
378          * to read-ahead in that case anyway...
379          */
380         if (oi->ip_dyn_features & OCFS2_INLINE_DATA_FL)
381                 goto out_unlock;
382 
383         /*
384          * Check whether a remote node truncated this file - we just
385          * drop out in that case as it's not worth handling here.
386          */
387         last = list_entry(pages->prev, struct page, lru);
388         start = (loff_t)last->index << PAGE_SHIFT;
389         if (start >= i_size_read(inode))
390                 goto out_unlock;
391 
392         err = mpage_readpages(mapping, pages, nr_pages, ocfs2_get_block);
393 
394 out_unlock:
395         up_read(&oi->ip_alloc_sem);
396         ocfs2_inode_unlock(inode, 0);
397 
398         return err;
399 }
400 
401 /* Note: Because we don't support holes, our allocation has
402  * already happened (allocation writes zeros to the file data)
403  * so we don't have to worry about ordered writes in
404  * ocfs2_writepage.
405  *
406  * ->writepage is called during the process of invalidating the page cache
407  * during blocked lock processing.  It can't block on any cluster locks
408  * to during block mapping.  It's relying on the fact that the block
409  * mapping can't have disappeared under the dirty pages that it is
410  * being asked to write back.
411  */
412 static int ocfs2_writepage(struct page *page, struct writeback_control *wbc)
413 {
414         trace_ocfs2_writepage(
415                 (unsigned long long)OCFS2_I(page->mapping->host)->ip_blkno,
416                 page->index);
417 
418         return block_write_full_page(page, ocfs2_get_block, wbc);
419 }
420 
421 /* Taken from ext3. We don't necessarily need the full blown
422  * functionality yet, but IMHO it's better to cut and paste the whole
423  * thing so we can avoid introducing our own bugs (and easily pick up
424  * their fixes when they happen) --Mark */
425 int walk_page_buffers(  handle_t *handle,
426                         struct buffer_head *head,
427                         unsigned from,
428                         unsigned to,
429                         int *partial,
430                         int (*fn)(      handle_t *handle,
431                                         struct buffer_head *bh))
432 {
433         struct buffer_head *bh;
434         unsigned block_start, block_end;
435         unsigned blocksize = head->b_size;
436         int err, ret = 0;
437         struct buffer_head *next;
438 
439         for (   bh = head, block_start = 0;
440                 ret == 0 && (bh != head || !block_start);
441                 block_start = block_end, bh = next)
442         {
443                 next = bh->b_this_page;
444                 block_end = block_start + blocksize;
445                 if (block_end <= from || block_start >= to) {
446                         if (partial && !buffer_uptodate(bh))
447                                 *partial = 1;
448                         continue;
449                 }
450                 err = (*fn)(handle, bh);
451                 if (!ret)
452                         ret = err;
453         }
454         return ret;
455 }
456 
457 static sector_t ocfs2_bmap(struct address_space *mapping, sector_t block)
458 {
459         sector_t status;
460         u64 p_blkno = 0;
461         int err = 0;
462         struct inode *inode = mapping->host;
463 
464         trace_ocfs2_bmap((unsigned long long)OCFS2_I(inode)->ip_blkno,
465                          (unsigned long long)block);
466 
467         /*
468          * The swap code (ab-)uses ->bmap to get a block mapping and then
469          * bypasseѕ the file system for actual I/O.  We really can't allow
470          * that on refcounted inodes, so we have to skip out here.  And yes,
471          * 0 is the magic code for a bmap error..
472          */
473         if (ocfs2_is_refcount_inode(inode))
474                 return 0;
475 
476         /* We don't need to lock journal system files, since they aren't
477          * accessed concurrently from multiple nodes.
478          */
479         if (!INODE_JOURNAL(inode)) {
480                 err = ocfs2_inode_lock(inode, NULL, 0);
481                 if (err) {
482                         if (err != -ENOENT)
483                                 mlog_errno(err);
484                         goto bail;
485                 }
486                 down_read(&OCFS2_I(inode)->ip_alloc_sem);
487         }
488 
489         if (!(OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL))
490                 err = ocfs2_extent_map_get_blocks(inode, block, &p_blkno, NULL,
491                                                   NULL);
492 
493         if (!INODE_JOURNAL(inode)) {
494                 up_read(&OCFS2_I(inode)->ip_alloc_sem);
495                 ocfs2_inode_unlock(inode, 0);
496         }
497 
498         if (err) {
499                 mlog(ML_ERROR, "get_blocks() failed, block = %llu\n",
500                      (unsigned long long)block);
501                 mlog_errno(err);
502                 goto bail;
503         }
504 
505 bail:
506         status = err ? 0 : p_blkno;
507 
508         return status;
509 }
510 
511 static int ocfs2_releasepage(struct page *page, gfp_t wait)
512 {
513         if (!page_has_buffers(page))
514                 return 0;
515         return try_to_free_buffers(page);
516 }
517 
518 static void ocfs2_figure_cluster_boundaries(struct ocfs2_super *osb,
519                                             u32 cpos,
520                                             unsigned int *start,
521                                             unsigned int *end)
522 {
523         unsigned int cluster_start = 0, cluster_end = PAGE_SIZE;
524 
525         if (unlikely(PAGE_SHIFT > osb->s_clustersize_bits)) {
526                 unsigned int cpp;
527 
528                 cpp = 1 << (PAGE_SHIFT - osb->s_clustersize_bits);
529 
530                 cluster_start = cpos % cpp;
531                 cluster_start = cluster_start << osb->s_clustersize_bits;
532 
533                 cluster_end = cluster_start + osb->s_clustersize;
534         }
535 
536         BUG_ON(cluster_start > PAGE_SIZE);
537         BUG_ON(cluster_end > PAGE_SIZE);
538 
539         if (start)
540                 *start = cluster_start;
541         if (end)
542                 *end = cluster_end;
543 }
544 
545 /*
546  * 'from' and 'to' are the region in the page to avoid zeroing.
547  *
548  * If pagesize > clustersize, this function will avoid zeroing outside
549  * of the cluster boundary.
550  *
551  * from == to == 0 is code for "zero the entire cluster region"
552  */
553 static void ocfs2_clear_page_regions(struct page *page,
554                                      struct ocfs2_super *osb, u32 cpos,
555                                      unsigned from, unsigned to)
556 {
557         void *kaddr;
558         unsigned int cluster_start, cluster_end;
559 
560         ocfs2_figure_cluster_boundaries(osb, cpos, &cluster_start, &cluster_end);
561 
562         kaddr = kmap_atomic(page);
563 
564         if (from || to) {
565                 if (from > cluster_start)
566                         memset(kaddr + cluster_start, 0, from - cluster_start);
567                 if (to < cluster_end)
568                         memset(kaddr + to, 0, cluster_end - to);
569         } else {
570                 memset(kaddr + cluster_start, 0, cluster_end - cluster_start);
571         }
572 
573         kunmap_atomic(kaddr);
574 }
575 
576 /*
577  * Nonsparse file systems fully allocate before we get to the write
578  * code. This prevents ocfs2_write() from tagging the write as an
579  * allocating one, which means ocfs2_map_page_blocks() might try to
580  * read-in the blocks at the tail of our file. Avoid reading them by
581  * testing i_size against each block offset.
582  */
583 static int ocfs2_should_read_blk(struct inode *inode, struct page *page,
584                                  unsigned int block_start)
585 {
586         u64 offset = page_offset(page) + block_start;
587 
588         if (ocfs2_sparse_alloc(OCFS2_SB(inode->i_sb)))
589                 return 1;
590 
591         if (i_size_read(inode) > offset)
592                 return 1;
593 
594         return 0;
595 }
596 
597 /*
598  * Some of this taken from __block_write_begin(). We already have our
599  * mapping by now though, and the entire write will be allocating or
600  * it won't, so not much need to use BH_New.
601  *
602  * This will also skip zeroing, which is handled externally.
603  */
604 int ocfs2_map_page_blocks(struct page *page, u64 *p_blkno,
605                           struct inode *inode, unsigned int from,
606                           unsigned int to, int new)
607 {
608         int ret = 0;
609         struct buffer_head *head, *bh, *wait[2], **wait_bh = wait;
610         unsigned int block_end, block_start;
611         unsigned int bsize = i_blocksize(inode);
612 
613         if (!page_has_buffers(page))
614                 create_empty_buffers(page, bsize, 0);
615 
616         head = page_buffers(page);
617         for (bh = head, block_start = 0; bh != head || !block_start;
618              bh = bh->b_this_page, block_start += bsize) {
619                 block_end = block_start + bsize;
620 
621                 clear_buffer_new(bh);
622 
623                 /*
624                  * Ignore blocks outside of our i/o range -
625                  * they may belong to unallocated clusters.
626                  */
627                 if (block_start >= to || block_end <= from) {
628                         if (PageUptodate(page))
629                                 set_buffer_uptodate(bh);
630                         continue;
631                 }
632 
633                 /*
634                  * For an allocating write with cluster size >= page
635                  * size, we always write the entire page.
636                  */
637                 if (new)
638                         set_buffer_new(bh);
639 
640                 if (!buffer_mapped(bh)) {
641                         map_bh(bh, inode->i_sb, *p_blkno);
642                         clean_bdev_bh_alias(bh);
643                 }
644 
645                 if (PageUptodate(page)) {
646                         if (!buffer_uptodate(bh))
647                                 set_buffer_uptodate(bh);
648                 } else if (!buffer_uptodate(bh) && !buffer_delay(bh) &&
649                            !buffer_new(bh) &&
650                            ocfs2_should_read_blk(inode, page, block_start) &&
651                            (block_start < from || block_end > to)) {
652                         ll_rw_block(REQ_OP_READ, 0, 1, &bh);
653                         *wait_bh++=bh;
654                 }
655 
656                 *p_blkno = *p_blkno + 1;
657         }
658 
659         /*
660          * If we issued read requests - let them complete.
661          */
662         while(wait_bh > wait) {
663                 wait_on_buffer(*--wait_bh);
664                 if (!buffer_uptodate(*wait_bh))
665                         ret = -EIO;
666         }
667 
668         if (ret == 0 || !new)
669                 return ret;
670 
671         /*
672          * If we get -EIO above, zero out any newly allocated blocks
673          * to avoid exposing stale data.
674          */
675         bh = head;
676         block_start = 0;
677         do {
678                 block_end = block_start + bsize;
679                 if (block_end <= from)
680                         goto next_bh;
681                 if (block_start >= to)
682                         break;
683 
684                 zero_user(page, block_start, bh->b_size);
685                 set_buffer_uptodate(bh);
686                 mark_buffer_dirty(bh);
687 
688 next_bh:
689                 block_start = block_end;
690                 bh = bh->b_this_page;
691         } while (bh != head);
692 
693         return ret;
694 }
695 
696 #if (PAGE_SIZE >= OCFS2_MAX_CLUSTERSIZE)
697 #define OCFS2_MAX_CTXT_PAGES    1
698 #else
699 #define OCFS2_MAX_CTXT_PAGES    (OCFS2_MAX_CLUSTERSIZE / PAGE_SIZE)
700 #endif
701 
702 #define OCFS2_MAX_CLUSTERS_PER_PAGE     (PAGE_SIZE / OCFS2_MIN_CLUSTERSIZE)
703 
704 struct ocfs2_unwritten_extent {
705         struct list_head        ue_node;
706         struct list_head        ue_ip_node;
707         u32                     ue_cpos;
708         u32                     ue_phys;
709 };
710 
711 /*
712  * Describe the state of a single cluster to be written to.
713  */
714 struct ocfs2_write_cluster_desc {
715         u32             c_cpos;
716         u32             c_phys;
717         /*
718          * Give this a unique field because c_phys eventually gets
719          * filled.
720          */
721         unsigned        c_new;
722         unsigned        c_clear_unwritten;
723         unsigned        c_needs_zero;
724 };
725 
726 struct ocfs2_write_ctxt {
727         /* Logical cluster position / len of write */
728         u32                             w_cpos;
729         u32                             w_clen;
730 
731         /* First cluster allocated in a nonsparse extend */
732         u32                             w_first_new_cpos;
733 
734         /* Type of caller. Must be one of buffer, mmap, direct.  */
735         ocfs2_write_type_t              w_type;
736 
737         struct ocfs2_write_cluster_desc w_desc[OCFS2_MAX_CLUSTERS_PER_PAGE];
738 
739         /*
740          * This is true if page_size > cluster_size.
741          *
742          * It triggers a set of special cases during write which might
743          * have to deal with allocating writes to partial pages.
744          */
745         unsigned int                    w_large_pages;
746 
747         /*
748          * Pages involved in this write.
749          *
750          * w_target_page is the page being written to by the user.
751          *
752          * w_pages is an array of pages which always contains
753          * w_target_page, and in the case of an allocating write with
754          * page_size < cluster size, it will contain zero'd and mapped
755          * pages adjacent to w_target_page which need to be written
756          * out in so that future reads from that region will get
757          * zero's.
758          */
759         unsigned int                    w_num_pages;
760         struct page                     *w_pages[OCFS2_MAX_CTXT_PAGES];
761         struct page                     *w_target_page;
762 
763         /*
764          * w_target_locked is used for page_mkwrite path indicating no unlocking
765          * against w_target_page in ocfs2_write_end_nolock.
766          */
767         unsigned int                    w_target_locked:1;
768 
769         /*
770          * ocfs2_write_end() uses this to know what the real range to
771          * write in the target should be.
772          */
773         unsigned int                    w_target_from;
774         unsigned int                    w_target_to;
775 
776         /*
777          * We could use journal_current_handle() but this is cleaner,
778          * IMHO -Mark
779          */
780         handle_t                        *w_handle;
781 
782         struct buffer_head              *w_di_bh;
783 
784         struct ocfs2_cached_dealloc_ctxt w_dealloc;
785 
786         struct list_head                w_unwritten_list;
787 };
788 
789 void ocfs2_unlock_and_free_pages(struct page **pages, int num_pages)
790 {
791         int i;
792 
793         for(i = 0; i < num_pages; i++) {
794                 if (pages[i]) {
795                         unlock_page(pages[i]);
796                         mark_page_accessed(pages[i]);
797                         put_page(pages[i]);
798                 }
799         }
800 }
801 
802 static void ocfs2_unlock_pages(struct ocfs2_write_ctxt *wc)
803 {
804         int i;
805 
806         /*
807          * w_target_locked is only set to true in the page_mkwrite() case.
808          * The intent is to allow us to lock the target page from write_begin()
809          * to write_end(). The caller must hold a ref on w_target_page.
810          */
811         if (wc->w_target_locked) {
812                 BUG_ON(!wc->w_target_page);
813                 for (i = 0; i < wc->w_num_pages; i++) {
814                         if (wc->w_target_page == wc->w_pages[i]) {
815                                 wc->w_pages[i] = NULL;
816                                 break;
817                         }
818                 }
819                 mark_page_accessed(wc->w_target_page);
820                 put_page(wc->w_target_page);
821         }
822         ocfs2_unlock_and_free_pages(wc->w_pages, wc->w_num_pages);
823 }
824 
825 static void ocfs2_free_unwritten_list(struct inode *inode,
826                                  struct list_head *head)
827 {
828         struct ocfs2_inode_info *oi = OCFS2_I(inode);
829         struct ocfs2_unwritten_extent *ue = NULL, *tmp = NULL;
830 
831         list_for_each_entry_safe(ue, tmp, head, ue_node) {
832                 list_del(&ue->ue_node);
833                 spin_lock(&oi->ip_lock);
834                 list_del(&ue->ue_ip_node);
835                 spin_unlock(&oi->ip_lock);
836                 kfree(ue);
837         }
838 }
839 
840 static void ocfs2_free_write_ctxt(struct inode *inode,
841                                   struct ocfs2_write_ctxt *wc)
842 {
843         ocfs2_free_unwritten_list(inode, &wc->w_unwritten_list);
844         ocfs2_unlock_pages(wc);
845         brelse(wc->w_di_bh);
846         kfree(wc);
847 }
848 
849 static int ocfs2_alloc_write_ctxt(struct ocfs2_write_ctxt **wcp,
850                                   struct ocfs2_super *osb, loff_t pos,
851                                   unsigned len, ocfs2_write_type_t type,
852                                   struct buffer_head *di_bh)
853 {
854         u32 cend;
855         struct ocfs2_write_ctxt *wc;
856 
857         wc = kzalloc(sizeof(struct ocfs2_write_ctxt), GFP_NOFS);
858         if (!wc)
859                 return -ENOMEM;
860 
861         wc->w_cpos = pos >> osb->s_clustersize_bits;
862         wc->w_first_new_cpos = UINT_MAX;
863         cend = (pos + len - 1) >> osb->s_clustersize_bits;
864         wc->w_clen = cend - wc->w_cpos + 1;
865         get_bh(di_bh);
866         wc->w_di_bh = di_bh;
867         wc->w_type = type;
868 
869         if (unlikely(PAGE_SHIFT > osb->s_clustersize_bits))
870                 wc->w_large_pages = 1;
871         else
872                 wc->w_large_pages = 0;
873 
874         ocfs2_init_dealloc_ctxt(&wc->w_dealloc);
875         INIT_LIST_HEAD(&wc->w_unwritten_list);
876 
877         *wcp = wc;
878 
879         return 0;
880 }
881 
882 /*
883  * If a page has any new buffers, zero them out here, and mark them uptodate
884  * and dirty so they'll be written out (in order to prevent uninitialised
885  * block data from leaking). And clear the new bit.
886  */
887 static void ocfs2_zero_new_buffers(struct page *page, unsigned from, unsigned to)
888 {
889         unsigned int block_start, block_end;
890         struct buffer_head *head, *bh;
891 
892         BUG_ON(!PageLocked(page));
893         if (!page_has_buffers(page))
894                 return;
895 
896         bh = head = page_buffers(page);
897         block_start = 0;
898         do {
899                 block_end = block_start + bh->b_size;
900 
901                 if (buffer_new(bh)) {
902                         if (block_end > from && block_start < to) {
903                                 if (!PageUptodate(page)) {
904                                         unsigned start, end;
905 
906                                         start = max(from, block_start);
907                                         end = min(to, block_end);
908 
909                                         zero_user_segment(page, start, end);
910                                         set_buffer_uptodate(bh);
911                                 }
912 
913                                 clear_buffer_new(bh);
914                                 mark_buffer_dirty(bh);
915                         }
916                 }
917 
918                 block_start = block_end;
919                 bh = bh->b_this_page;
920         } while (bh != head);
921 }
922 
923 /*
924  * Only called when we have a failure during allocating write to write
925  * zero's to the newly allocated region.
926  */
927 static void ocfs2_write_failure(struct inode *inode,
928                                 struct ocfs2_write_ctxt *wc,
929                                 loff_t user_pos, unsigned user_len)
930 {
931         int i;
932         unsigned from = user_pos & (PAGE_SIZE - 1),
933                 to = user_pos + user_len;
934         struct page *tmppage;
935 
936         if (wc->w_target_page)
937                 ocfs2_zero_new_buffers(wc->w_target_page, from, to);
938 
939         for(i = 0; i < wc->w_num_pages; i++) {
940                 tmppage = wc->w_pages[i];
941 
942                 if (tmppage && page_has_buffers(tmppage)) {
943                         if (ocfs2_should_order_data(inode))
944                                 ocfs2_jbd2_file_inode(wc->w_handle, inode);
945 
946                         block_commit_write(tmppage, from, to);
947                 }
948         }
949 }
950 
951 static int ocfs2_prepare_page_for_write(struct inode *inode, u64 *p_blkno,
952                                         struct ocfs2_write_ctxt *wc,
953                                         struct page *page, u32 cpos,
954                                         loff_t user_pos, unsigned user_len,
955                                         int new)
956 {
957         int ret;
958         unsigned int map_from = 0, map_to = 0;
959         unsigned int cluster_start, cluster_end;
960         unsigned int user_data_from = 0, user_data_to = 0;
961 
962         ocfs2_figure_cluster_boundaries(OCFS2_SB(inode->i_sb), cpos,
963                                         &cluster_start, &cluster_end);
964 
965         /* treat the write as new if the a hole/lseek spanned across
966          * the page boundary.
967          */
968         new = new | ((i_size_read(inode) <= page_offset(page)) &&
969                         (page_offset(page) <= user_pos));
970 
971         if (page == wc->w_target_page) {
972                 map_from = user_pos & (PAGE_SIZE - 1);
973                 map_to = map_from + user_len;
974 
975                 if (new)
976                         ret = ocfs2_map_page_blocks(page, p_blkno, inode,
977                                                     cluster_start, cluster_end,
978                                                     new);
979                 else
980                         ret = ocfs2_map_page_blocks(page, p_blkno, inode,
981                                                     map_from, map_to, new);
982                 if (ret) {
983                         mlog_errno(ret);
984                         goto out;
985                 }
986 
987                 user_data_from = map_from;
988                 user_data_to = map_to;
989                 if (new) {
990                         map_from = cluster_start;
991                         map_to = cluster_end;
992                 }
993         } else {
994                 /*
995                  * If we haven't allocated the new page yet, we
996                  * shouldn't be writing it out without copying user
997                  * data. This is likely a math error from the caller.
998                  */
999                 BUG_ON(!new);
1000 
1001                 map_from = cluster_start;
1002                 map_to = cluster_end;
1003 
1004                 ret = ocfs2_map_page_blocks(page, p_blkno, inode,
1005                                             cluster_start, cluster_end, new);
1006                 if (ret) {
1007                         mlog_errno(ret);
1008                         goto out;
1009                 }
1010         }
1011 
1012         /*
1013          * Parts of newly allocated pages need to be zero'd.
1014          *
1015          * Above, we have also rewritten 'to' and 'from' - as far as
1016          * the rest of the function is concerned, the entire cluster
1017          * range inside of a page needs to be written.
1018          *
1019          * We can skip this if the page is up to date - it's already
1020          * been zero'd from being read in as a hole.
1021          */
1022         if (new && !PageUptodate(page))
1023                 ocfs2_clear_page_regions(page, OCFS2_SB(inode->i_sb),
1024                                          cpos, user_data_from, user_data_to);
1025 
1026         flush_dcache_page(page);
1027 
1028 out:
1029         return ret;
1030 }
1031 
1032 /*
1033  * This function will only grab one clusters worth of pages.
1034  */
1035 static int ocfs2_grab_pages_for_write(struct address_space *mapping,
1036                                       struct ocfs2_write_ctxt *wc,
1037                                       u32 cpos, loff_t user_pos,
1038                                       unsigned user_len, int new,
1039                                       struct page *mmap_page)
1040 {
1041         int ret = 0, i;
1042         unsigned long start, target_index, end_index, index;
1043         struct inode *inode = mapping->host;
1044         loff_t last_byte;
1045 
1046         target_index = user_pos >> PAGE_SHIFT;
1047 
1048         /*
1049          * Figure out how many pages we'll be manipulating here. For
1050          * non allocating write, we just change the one
1051          * page. Otherwise, we'll need a whole clusters worth.  If we're
1052          * writing past i_size, we only need enough pages to cover the
1053          * last page of the write.
1054          */
1055         if (new) {
1056                 wc->w_num_pages = ocfs2_pages_per_cluster(inode->i_sb);
1057                 start = ocfs2_align_clusters_to_page_index(inode->i_sb, cpos);
1058                 /*
1059                  * We need the index *past* the last page we could possibly
1060                  * touch.  This is the page past the end of the write or
1061                  * i_size, whichever is greater.
1062                  */
1063                 last_byte = max(user_pos + user_len, i_size_read(inode));
1064                 BUG_ON(last_byte < 1);
1065                 end_index = ((last_byte - 1) >> PAGE_SHIFT) + 1;
1066                 if ((start + wc->w_num_pages) > end_index)
1067                         wc->w_num_pages = end_index - start;
1068         } else {
1069                 wc->w_num_pages = 1;
1070                 start = target_index;
1071         }
1072         end_index = (user_pos + user_len - 1) >> PAGE_SHIFT;
1073 
1074         for(i = 0; i < wc->w_num_pages; i++) {
1075                 index = start + i;
1076 
1077                 if (index >= target_index && index <= end_index &&
1078                     wc->w_type == OCFS2_WRITE_MMAP) {
1079                         /*
1080                          * ocfs2_pagemkwrite() is a little different
1081                          * and wants us to directly use the page
1082                          * passed in.
1083                          */
1084                         lock_page(mmap_page);
1085 
1086                         /* Exit and let the caller retry */
1087                         if (mmap_page->mapping != mapping) {
1088                                 WARN_ON(mmap_page->mapping);
1089                                 unlock_page(mmap_page);
1090                                 ret = -EAGAIN;
1091                                 goto out;
1092                         }
1093 
1094                         get_page(mmap_page);
1095                         wc->w_pages[i] = mmap_page;
1096                         wc->w_target_locked = true;
1097                 } else if (index >= target_index && index <= end_index &&
1098                            wc->w_type == OCFS2_WRITE_DIRECT) {
1099                         /* Direct write has no mapping page. */
1100                         wc->w_pages[i] = NULL;
1101                         continue;
1102                 } else {
1103                         wc->w_pages[i] = find_or_create_page(mapping, index,
1104                                                              GFP_NOFS);
1105                         if (!wc->w_pages[i]) {
1106                                 ret = -ENOMEM;
1107                                 mlog_errno(ret);
1108                                 goto out;
1109                         }
1110                 }
1111                 wait_for_stable_page(wc->w_pages[i]);
1112 
1113                 if (index == target_index)
1114                         wc->w_target_page = wc->w_pages[i];
1115         }
1116 out:
1117         if (ret)
1118                 wc->w_target_locked = false;
1119         return ret;
1120 }
1121 
1122 /*
1123  * Prepare a single cluster for write one cluster into the file.
1124  */
1125 static int ocfs2_write_cluster(struct address_space *mapping,
1126                                u32 *phys, unsigned int new,
1127                                unsigned int clear_unwritten,
1128                                unsigned int should_zero,
1129                                struct ocfs2_alloc_context *data_ac,
1130                                struct ocfs2_alloc_context *meta_ac,
1131                                struct ocfs2_write_ctxt *wc, u32 cpos,
1132                                loff_t user_pos, unsigned user_len)
1133 {
1134         int ret, i;
1135         u64 p_blkno;
1136         struct inode *inode = mapping->host;
1137         struct ocfs2_extent_tree et;
1138         int bpc = ocfs2_clusters_to_blocks(inode->i_sb, 1);
1139 
1140         if (new) {
1141                 u32 tmp_pos;
1142 
1143                 /*
1144                  * This is safe to call with the page locks - it won't take
1145                  * any additional semaphores or cluster locks.
1146                  */
1147                 tmp_pos = cpos;
1148                 ret = ocfs2_add_inode_data(OCFS2_SB(inode->i_sb), inode,
1149                                            &tmp_pos, 1, !clear_unwritten,
1150                                            wc->w_di_bh, wc->w_handle,
1151                                            data_ac, meta_ac, NULL);
1152                 /*
1153                  * This shouldn't happen because we must have already
1154                  * calculated the correct meta data allocation required. The
1155                  * internal tree allocation code should know how to increase
1156                  * transaction credits itself.
1157                  *
1158                  * If need be, we could handle -EAGAIN for a
1159                  * RESTART_TRANS here.
1160                  */
1161                 mlog_bug_on_msg(ret == -EAGAIN,
1162                                 "Inode %llu: EAGAIN return during allocation.\n",
1163                                 (unsigned long long)OCFS2_I(inode)->ip_blkno);
1164                 if (ret < 0) {
1165                         mlog_errno(ret);
1166                         goto out;
1167                 }
1168         } else if (clear_unwritten) {
1169                 ocfs2_init_dinode_extent_tree(&et, INODE_CACHE(inode),
1170                                               wc->w_di_bh);
1171                 ret = ocfs2_mark_extent_written(inode, &et,
1172                                                 wc->w_handle, cpos, 1, *phys,
1173                                                 meta_ac, &wc->w_dealloc);
1174                 if (ret < 0) {
1175                         mlog_errno(ret);
1176                         goto out;
1177                 }
1178         }
1179 
1180         /*
1181          * The only reason this should fail is due to an inability to
1182          * find the extent added.
1183          */
1184         ret = ocfs2_get_clusters(inode, cpos, phys, NULL, NULL);
1185         if (ret < 0) {
1186                 mlog(ML_ERROR, "Get physical blkno failed for inode %llu, "
1187                             "at logical cluster %u",
1188                             (unsigned long long)OCFS2_I(inode)->ip_blkno, cpos);
1189                 goto out;
1190         }
1191 
1192         BUG_ON(*phys == 0);
1193 
1194         p_blkno = ocfs2_clusters_to_blocks(inode->i_sb, *phys);
1195         if (!should_zero)
1196                 p_blkno += (user_pos >> inode->i_sb->s_blocksize_bits) & (u64)(bpc - 1);
1197 
1198         for(i = 0; i < wc->w_num_pages; i++) {
1199                 int tmpret;
1200 
1201                 /* This is the direct io target page. */
1202                 if (wc->w_pages[i] == NULL) {
1203                         p_blkno++;
1204                         continue;
1205                 }
1206 
1207                 tmpret = ocfs2_prepare_page_for_write(inode, &p_blkno, wc,
1208                                                       wc->w_pages[i], cpos,
1209                                                       user_pos, user_len,
1210                                                       should_zero);
1211                 if (tmpret) {
1212                         mlog_errno(tmpret);
1213                         if (ret == 0)
1214                                 ret = tmpret;
1215                 }
1216         }
1217 
1218         /*
1219          * We only have cleanup to do in case of allocating write.
1220          */
1221         if (ret && new)
1222                 ocfs2_write_failure(inode, wc, user_pos, user_len);
1223 
1224 out:
1225 
1226         return ret;
1227 }
1228 
1229 static int ocfs2_write_cluster_by_desc(struct address_space *mapping,
1230                                        struct ocfs2_alloc_context *data_ac,
1231                                        struct ocfs2_alloc_context *meta_ac,
1232                                        struct ocfs2_write_ctxt *wc,
1233                                        loff_t pos, unsigned len)
1234 {
1235         int ret, i;
1236         loff_t cluster_off;
1237         unsigned int local_len = len;
1238         struct ocfs2_write_cluster_desc *desc;
1239         struct ocfs2_super *osb = OCFS2_SB(mapping->host->i_sb);
1240 
1241         for (i = 0; i < wc->w_clen; i++) {
1242                 desc = &wc->w_desc[i];
1243 
1244                 /*
1245                  * We have to make sure that the total write passed in
1246                  * doesn't extend past a single cluster.
1247                  */
1248                 local_len = len;
1249                 cluster_off = pos & (osb->s_clustersize - 1);
1250                 if ((cluster_off + local_len) > osb->s_clustersize)
1251                         local_len = osb->s_clustersize - cluster_off;
1252 
1253                 ret = ocfs2_write_cluster(mapping, &desc->c_phys,
1254                                           desc->c_new,
1255                                           desc->c_clear_unwritten,
1256                                           desc->c_needs_zero,
1257                                           data_ac, meta_ac,
1258                                           wc, desc->c_cpos, pos, local_len);
1259                 if (ret) {
1260                         mlog_errno(ret);
1261                         goto out;
1262                 }
1263 
1264                 len -= local_len;
1265                 pos += local_len;
1266         }
1267 
1268         ret = 0;
1269 out:
1270         return ret;
1271 }
1272 
1273 /*
1274  * ocfs2_write_end() wants to know which parts of the target page it
1275  * should complete the write on. It's easiest to compute them ahead of
1276  * time when a more complete view of the write is available.
1277  */
1278 static void ocfs2_set_target_boundaries(struct ocfs2_super *osb,
1279                                         struct ocfs2_write_ctxt *wc,
1280                                         loff_t pos, unsigned len, int alloc)
1281 {
1282         struct ocfs2_write_cluster_desc *desc;
1283 
1284         wc->w_target_from = pos & (PAGE_SIZE - 1);
1285         wc->w_target_to = wc->w_target_from + len;
1286 
1287         if (alloc == 0)
1288                 return;
1289 
1290         /*
1291          * Allocating write - we may have different boundaries based
1292          * on page size and cluster size.
1293          *
1294          * NOTE: We can no longer compute one value from the other as
1295          * the actual write length and user provided length may be
1296          * different.
1297          */
1298 
1299         if (wc->w_large_pages) {
1300                 /*
1301                  * We only care about the 1st and last cluster within
1302                  * our range and whether they should be zero'd or not. Either
1303                  * value may be extended out to the start/end of a
1304                  * newly allocated cluster.
1305                  */
1306                 desc = &wc->w_desc[0];
1307                 if (desc->c_needs_zero)
1308                         ocfs2_figure_cluster_boundaries(osb,
1309                                                         desc->c_cpos,
1310                                                         &wc->w_target_from,
1311                                                         NULL);
1312 
1313                 desc = &wc->w_desc[wc->w_clen - 1];
1314                 if (desc->c_needs_zero)
1315                         ocfs2_figure_cluster_boundaries(osb,
1316                                                         desc->c_cpos,
1317                                                         NULL,
1318                                                         &wc->w_target_to);
1319         } else {
1320                 wc->w_target_from = 0;
1321                 wc->w_target_to = PAGE_SIZE;
1322         }
1323 }
1324 
1325 /*
1326  * Check if this extent is marked UNWRITTEN by direct io. If so, we need not to
1327  * do the zero work. And should not to clear UNWRITTEN since it will be cleared
1328  * by the direct io procedure.
1329  * If this is a new extent that allocated by direct io, we should mark it in
1330  * the ip_unwritten_list.
1331  */
1332 static int ocfs2_unwritten_check(struct inode *inode,
1333                                  struct ocfs2_write_ctxt *wc,
1334                                  struct ocfs2_write_cluster_desc *desc)
1335 {
1336         struct ocfs2_inode_info *oi = OCFS2_I(inode);
1337         struct ocfs2_unwritten_extent *ue = NULL, *new = NULL;
1338         int ret = 0;
1339 
1340         if (!desc->c_needs_zero)
1341                 return 0;
1342 
1343 retry:
1344         spin_lock(&oi->ip_lock);
1345         /* Needs not to zero no metter buffer or direct. The one who is zero
1346          * the cluster is doing zero. And he will clear unwritten after all
1347          * cluster io finished. */
1348         list_for_each_entry(ue, &oi->ip_unwritten_list, ue_ip_node) {
1349                 if (desc->c_cpos == ue->ue_cpos) {
1350                         BUG_ON(desc->c_new);
1351                         desc->c_needs_zero = 0;
1352                         desc->c_clear_unwritten = 0;
1353                         goto unlock;
1354                 }
1355         }
1356 
1357         if (wc->w_type != OCFS2_WRITE_DIRECT)
1358                 goto unlock;
1359 
1360         if (new == NULL) {
1361                 spin_unlock(&oi->ip_lock);
1362                 new = kmalloc(sizeof(struct ocfs2_unwritten_extent),
1363                              GFP_NOFS);
1364                 if (new == NULL) {
1365                         ret = -ENOMEM;
1366                         goto out;
1367                 }
1368                 goto retry;
1369         }
1370         /* This direct write will doing zero. */
1371         new->ue_cpos = desc->c_cpos;
1372         new->ue_phys = desc->c_phys;
1373         desc->c_clear_unwritten = 0;
1374         list_add_tail(&new->ue_ip_node, &oi->ip_unwritten_list);
1375         list_add_tail(&new->ue_node, &wc->w_unwritten_list);
1376         new = NULL;
1377 unlock:
1378         spin_unlock(&oi->ip_lock);
1379 out:
1380         if (new)
1381                 kfree(new);
1382         return ret;
1383 }
1384 
1385 /*
1386  * Populate each single-cluster write descriptor in the write context
1387  * with information about the i/o to be done.
1388  *
1389  * Returns the number of clusters that will have to be allocated, as
1390  * well as a worst case estimate of the number of extent records that
1391  * would have to be created during a write to an unwritten region.
1392  */
1393 static int ocfs2_populate_write_desc(struct inode *inode,
1394                                      struct ocfs2_write_ctxt *wc,
1395                                      unsigned int *clusters_to_alloc,
1396                                      unsigned int *extents_to_split)
1397 {
1398         int ret;
1399         struct ocfs2_write_cluster_desc *desc;
1400         unsigned int num_clusters = 0;
1401         unsigned int ext_flags = 0;
1402         u32 phys = 0;
1403         int i;
1404 
1405         *clusters_to_alloc = 0;
1406         *extents_to_split = 0;
1407 
1408         for (i = 0; i < wc->w_clen; i++) {
1409                 desc = &wc->w_desc[i];
1410                 desc->c_cpos = wc->w_cpos + i;
1411 
1412                 if (num_clusters == 0) {
1413                         /*
1414                          * Need to look up the next extent record.
1415                          */
1416                         ret = ocfs2_get_clusters(inode, desc->c_cpos, &phys,
1417                                                  &num_clusters, &ext_flags);
1418                         if (ret) {
1419                                 mlog_errno(ret);
1420                                 goto out;
1421                         }
1422 
1423                         /* We should already CoW the refcountd extent. */
1424                         BUG_ON(ext_flags & OCFS2_EXT_REFCOUNTED);
1425 
1426                         /*
1427                          * Assume worst case - that we're writing in
1428                          * the middle of the extent.
1429                          *
1430                          * We can assume that the write proceeds from
1431                          * left to right, in which case the extent
1432                          * insert code is smart enough to coalesce the
1433                          * next splits into the previous records created.
1434                          */
1435                         if (ext_flags & OCFS2_EXT_UNWRITTEN)
1436                                 *extents_to_split = *extents_to_split + 2;
1437                 } else if (phys) {
1438                         /*
1439                          * Only increment phys if it doesn't describe
1440                          * a hole.
1441                          */
1442                         phys++;
1443                 }
1444 
1445                 /*
1446                  * If w_first_new_cpos is < UINT_MAX, we have a non-sparse
1447                  * file that got extended.  w_first_new_cpos tells us
1448                  * where the newly allocated clusters are so we can
1449                  * zero them.
1450                  */
1451                 if (desc->c_cpos >= wc->w_first_new_cpos) {
1452                         BUG_ON(phys == 0);
1453                         desc->c_needs_zero = 1;
1454                 }
1455 
1456                 desc->c_phys = phys;
1457                 if (phys == 0) {
1458                         desc->c_new = 1;
1459                         desc->c_needs_zero = 1;
1460                         desc->c_clear_unwritten = 1;
1461                         *clusters_to_alloc = *clusters_to_alloc + 1;
1462                 }
1463 
1464                 if (ext_flags & OCFS2_EXT_UNWRITTEN) {
1465                         desc->c_clear_unwritten = 1;
1466                         desc->c_needs_zero = 1;
1467                 }
1468 
1469                 ret = ocfs2_unwritten_check(inode, wc, desc);
1470                 if (ret) {
1471                         mlog_errno(ret);
1472                         goto out;
1473                 }
1474 
1475                 num_clusters--;
1476         }
1477 
1478         ret = 0;
1479 out:
1480         return ret;
1481 }
1482 
1483 static int ocfs2_write_begin_inline(struct address_space *mapping,
1484                                     struct inode *inode,
1485                                     struct ocfs2_write_ctxt *wc)
1486 {
1487         int ret;
1488         struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
1489         struct page *page;
1490         handle_t *handle;
1491         struct ocfs2_dinode *di = (struct ocfs2_dinode *)wc->w_di_bh->b_data;
1492 
1493         handle = ocfs2_start_trans(osb, OCFS2_INODE_UPDATE_CREDITS);
1494         if (IS_ERR(handle)) {
1495                 ret = PTR_ERR(handle);
1496                 mlog_errno(ret);
1497                 goto out;
1498         }
1499 
1500         page = find_or_create_page(mapping, 0, GFP_NOFS);
1501         if (!page) {
1502                 ocfs2_commit_trans(osb, handle);
1503                 ret = -ENOMEM;
1504                 mlog_errno(ret);
1505                 goto out;
1506         }
1507         /*
1508          * If we don't set w_num_pages then this page won't get unlocked
1509          * and freed on cleanup of the write context.
1510          */
1511         wc->w_pages[0] = wc->w_target_page = page;
1512         wc->w_num_pages = 1;
1513 
1514         ret = ocfs2_journal_access_di(handle, INODE_CACHE(inode), wc->w_di_bh,
1515                                       OCFS2_JOURNAL_ACCESS_WRITE);
1516         if (ret) {
1517                 ocfs2_commit_trans(osb, handle);
1518 
1519                 mlog_errno(ret);
1520                 goto out;
1521         }
1522 
1523         if (!(OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL))
1524                 ocfs2_set_inode_data_inline(inode, di);
1525 
1526         if (!PageUptodate(page)) {
1527                 ret = ocfs2_read_inline_data(inode, page, wc->w_di_bh);
1528                 if (ret) {
1529                         ocfs2_commit_trans(osb, handle);
1530 
1531                         goto out;
1532                 }
1533         }
1534 
1535         wc->w_handle = handle;
1536 out:
1537         return ret;
1538 }
1539 
1540 int ocfs2_size_fits_inline_data(struct buffer_head *di_bh, u64 new_size)
1541 {
1542         struct ocfs2_dinode *di = (struct ocfs2_dinode *)di_bh->b_data;
1543 
1544         if (new_size <= le16_to_cpu(di->id2.i_data.id_count))
1545                 return 1;
1546         return 0;
1547 }
1548 
1549 static int ocfs2_try_to_write_inline_data(struct address_space *mapping,
1550                                           struct inode *inode, loff_t pos,
1551                                           unsigned len, struct page *mmap_page,
1552                                           struct ocfs2_write_ctxt *wc)
1553 {
1554         int ret, written = 0;
1555         loff_t end = pos + len;
1556         struct ocfs2_inode_info *oi = OCFS2_I(inode);
1557         struct ocfs2_dinode *di = NULL;
1558 
1559         trace_ocfs2_try_to_write_inline_data((unsigned long long)oi->ip_blkno,
1560                                              len, (unsigned long long)pos,
1561                                              oi->ip_dyn_features);
1562 
1563         /*
1564          * Handle inodes which already have inline data 1st.
1565          */
1566         if (oi->ip_dyn_features & OCFS2_INLINE_DATA_FL) {
1567                 if (mmap_page == NULL &&
1568                     ocfs2_size_fits_inline_data(wc->w_di_bh, end))
1569                         goto do_inline_write;
1570 
1571                 /*
1572                  * The write won't fit - we have to give this inode an
1573                  * inline extent list now.
1574                  */
1575                 ret = ocfs2_convert_inline_data_to_extents(inode, wc->w_di_bh);
1576                 if (ret)
1577                         mlog_errno(ret);
1578                 goto out;
1579         }
1580 
1581         /*
1582          * Check whether the inode can accept inline data.
1583          */
1584         if (oi->ip_clusters != 0 || i_size_read(inode) != 0)
1585                 return 0;
1586 
1587         /*
1588          * Check whether the write can fit.
1589          */
1590         di = (struct ocfs2_dinode *)wc->w_di_bh->b_data;
1591         if (mmap_page ||
1592             end > ocfs2_max_inline_data_with_xattr(inode->i_sb, di))
1593                 return 0;
1594 
1595 do_inline_write:
1596         ret = ocfs2_write_begin_inline(mapping, inode, wc);
1597         if (ret) {
1598                 mlog_errno(ret);
1599                 goto out;
1600         }
1601 
1602         /*
1603          * This signals to the caller that the data can be written
1604          * inline.
1605          */
1606         written = 1;
1607 out:
1608         return written ? written : ret;
1609 }
1610 
1611 /*
1612  * This function only does anything for file systems which can't
1613  * handle sparse files.
1614  *
1615  * What we want to do here is fill in any hole between the current end
1616  * of allocation and the end of our write. That way the rest of the
1617  * write path can treat it as an non-allocating write, which has no
1618  * special case code for sparse/nonsparse files.
1619  */
1620 static int ocfs2_expand_nonsparse_inode(struct inode *inode,
1621                                         struct buffer_head *di_bh,
1622                                         loff_t pos, unsigned len,
1623                                         struct ocfs2_write_ctxt *wc)
1624 {
1625         int ret;
1626         loff_t newsize = pos + len;
1627 
1628         BUG_ON(ocfs2_sparse_alloc(OCFS2_SB(inode->i_sb)));
1629 
1630         if (newsize <= i_size_read(inode))
1631                 return 0;
1632 
1633         ret = ocfs2_extend_no_holes(inode, di_bh, newsize, pos);
1634         if (ret)
1635                 mlog_errno(ret);
1636 
1637         /* There is no wc if this is call from direct. */
1638         if (wc)
1639                 wc->w_first_new_cpos =
1640                         ocfs2_clusters_for_bytes(inode->i_sb, i_size_read(inode));
1641 
1642         return ret;
1643 }
1644 
1645 static int ocfs2_zero_tail(struct inode *inode, struct buffer_head *di_bh,
1646                            loff_t pos)
1647 {
1648         int ret = 0;
1649 
1650         BUG_ON(!ocfs2_sparse_alloc(OCFS2_SB(inode->i_sb)));
1651         if (pos > i_size_read(inode))
1652                 ret = ocfs2_zero_extend(inode, di_bh, pos);
1653 
1654         return ret;
1655 }
1656 
1657 int ocfs2_write_begin_nolock(struct address_space *mapping,
1658                              loff_t pos, unsigned len, ocfs2_write_type_t type,
1659                              struct page **pagep, void **fsdata,
1660                              struct buffer_head *di_bh, struct page *mmap_page)
1661 {
1662         int ret, cluster_of_pages, credits = OCFS2_INODE_UPDATE_CREDITS;
1663         unsigned int clusters_to_alloc, extents_to_split, clusters_need = 0;
1664         struct ocfs2_write_ctxt *wc;
1665         struct inode *inode = mapping->host;
1666         struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
1667         struct ocfs2_dinode *di;
1668         struct ocfs2_alloc_context *data_ac = NULL;
1669         struct ocfs2_alloc_context *meta_ac = NULL;
1670         handle_t *handle;
1671         struct ocfs2_extent_tree et;
1672         int try_free = 1, ret1;
1673 
1674 try_again:
1675         ret = ocfs2_alloc_write_ctxt(&wc, osb, pos, len, type, di_bh);
1676         if (ret) {
1677                 mlog_errno(ret);
1678                 return ret;
1679         }
1680 
1681         if (ocfs2_supports_inline_data(osb)) {
1682                 ret = ocfs2_try_to_write_inline_data(mapping, inode, pos, len,
1683                                                      mmap_page, wc);
1684                 if (ret == 1) {
1685                         ret = 0;
1686                         goto success;
1687                 }
1688                 if (ret < 0) {
1689                         mlog_errno(ret);
1690                         goto out;
1691                 }
1692         }
1693 
1694         /* Direct io change i_size late, should not zero tail here. */
1695         if (type != OCFS2_WRITE_DIRECT) {
1696                 if (ocfs2_sparse_alloc(osb))
1697                         ret = ocfs2_zero_tail(inode, di_bh, pos);
1698                 else
1699                         ret = ocfs2_expand_nonsparse_inode(inode, di_bh, pos,
1700                                                            len, wc);
1701                 if (ret) {
1702                         mlog_errno(ret);
1703                         goto out;
1704                 }
1705         }
1706 
1707         ret = ocfs2_check_range_for_refcount(inode, pos, len);
1708         if (ret < 0) {
1709                 mlog_errno(ret);
1710                 goto out;
1711         } else if (ret == 1) {
1712                 clusters_need = wc->w_clen;
1713                 ret = ocfs2_refcount_cow(inode, di_bh,
1714                                          wc->w_cpos, wc->w_clen, UINT_MAX);
1715                 if (ret) {
1716                         mlog_errno(ret);
1717                         goto out;
1718                 }
1719         }
1720 
1721         ret = ocfs2_populate_write_desc(inode, wc, &clusters_to_alloc,
1722                                         &extents_to_split);
1723         if (ret) {
1724                 mlog_errno(ret);
1725                 goto out;
1726         }
1727         clusters_need += clusters_to_alloc;
1728 
1729         di = (struct ocfs2_dinode *)wc->w_di_bh->b_data;
1730 
1731         trace_ocfs2_write_begin_nolock(
1732                         (unsigned long long)OCFS2_I(inode)->ip_blkno,
1733                         (long long)i_size_read(inode),
1734                         le32_to_cpu(di->i_clusters),
1735                         pos, len, type, mmap_page,
1736                         clusters_to_alloc, extents_to_split);
1737 
1738         /*
1739          * We set w_target_from, w_target_to here so that
1740          * ocfs2_write_end() knows which range in the target page to
1741          * write out. An allocation requires that we write the entire
1742          * cluster range.
1743          */
1744         if (clusters_to_alloc || extents_to_split) {
1745                 /*
1746                  * XXX: We are stretching the limits of
1747                  * ocfs2_lock_allocators(). It greatly over-estimates
1748                  * the work to be done.
1749                  */
1750                 ocfs2_init_dinode_extent_tree(&et, INODE_CACHE(inode),
1751                                               wc->w_di_bh);
1752                 ret = ocfs2_lock_allocators(inode, &et,
1753                                             clusters_to_alloc, extents_to_split,
1754                                             &data_ac, &meta_ac);
1755                 if (ret) {
1756                         mlog_errno(ret);
1757                         goto out;
1758                 }
1759 
1760                 if (data_ac)
1761                         data_ac->ac_resv = &OCFS2_I(inode)->ip_la_data_resv;
1762 
1763                 credits = ocfs2_calc_extend_credits(inode->i_sb,
1764                                                     &di->id2.i_list);
1765         } else if (type == OCFS2_WRITE_DIRECT)
1766                 /* direct write needs not to start trans if no extents alloc. */
1767                 goto success;
1768 
1769         /*
1770          * We have to zero sparse allocated clusters, unwritten extent clusters,
1771          * and non-sparse clusters we just extended.  For non-sparse writes,
1772          * we know zeros will only be needed in the first and/or last cluster.
1773          */
1774         if (wc->w_clen && (wc->w_desc[0].c_needs_zero ||
1775                            wc->w_desc[wc->w_clen - 1].c_needs_zero))
1776                 cluster_of_pages = 1;
1777         else
1778                 cluster_of_pages = 0;
1779 
1780         ocfs2_set_target_boundaries(osb, wc, pos, len, cluster_of_pages);
1781 
1782         handle = ocfs2_start_trans(osb, credits);
1783         if (IS_ERR(handle)) {
1784                 ret = PTR_ERR(handle);
1785                 mlog_errno(ret);
1786                 goto out;
1787         }
1788 
1789         wc->w_handle = handle;
1790 
1791         if (clusters_to_alloc) {
1792                 ret = dquot_alloc_space_nodirty(inode,
1793                         ocfs2_clusters_to_bytes(osb->sb, clusters_to_alloc));
1794                 if (ret)
1795                         goto out_commit;
1796         }
1797 
1798         ret = ocfs2_journal_access_di(handle, INODE_CACHE(inode), wc->w_di_bh,
1799                                       OCFS2_JOURNAL_ACCESS_WRITE);
1800         if (ret) {
1801                 mlog_errno(ret);
1802                 goto out_quota;
1803         }
1804 
1805         /*
1806          * Fill our page array first. That way we've grabbed enough so
1807          * that we can zero and flush if we error after adding the
1808          * extent.
1809          */
1810         ret = ocfs2_grab_pages_for_write(mapping, wc, wc->w_cpos, pos, len,
1811                                          cluster_of_pages, mmap_page);
1812         if (ret && ret != -EAGAIN) {
1813                 mlog_errno(ret);
1814                 goto out_quota;
1815         }
1816 
1817         /*
1818          * ocfs2_grab_pages_for_write() returns -EAGAIN if it could not lock
1819          * the target page. In this case, we exit with no error and no target
1820          * page. This will trigger the caller, page_mkwrite(), to re-try
1821          * the operation.
1822          */
1823         if (ret == -EAGAIN) {
1824                 BUG_ON(wc->w_target_page);
1825                 ret = 0;
1826                 goto out_quota;
1827         }
1828 
1829         ret = ocfs2_write_cluster_by_desc(mapping, data_ac, meta_ac, wc, pos,
1830                                           len);
1831         if (ret) {
1832                 mlog_errno(ret);
1833                 goto out_quota;
1834         }
1835 
1836         if (data_ac)
1837                 ocfs2_free_alloc_context(data_ac);
1838         if (meta_ac)
1839                 ocfs2_free_alloc_context(meta_ac);
1840 
1841 success:
1842         if (pagep)
1843                 *pagep = wc->w_target_page;
1844         *fsdata = wc;
1845         return 0;
1846 out_quota:
1847         if (clusters_to_alloc)
1848                 dquot_free_space(inode,
1849                           ocfs2_clusters_to_bytes(osb->sb, clusters_to_alloc));
1850 out_commit:
1851         ocfs2_commit_trans(osb, handle);
1852 
1853 out:
1854         /*
1855          * The mmapped page won't be unlocked in ocfs2_free_write_ctxt(),
1856          * even in case of error here like ENOSPC and ENOMEM. So, we need
1857          * to unlock the target page manually to prevent deadlocks when
1858          * retrying again on ENOSPC, or when returning non-VM_FAULT_LOCKED
1859          * to VM code.
1860          */
1861         if (wc->w_target_locked)
1862                 unlock_page(mmap_page);
1863 
1864         ocfs2_free_write_ctxt(inode, wc);
1865 
1866         if (data_ac) {
1867                 ocfs2_free_alloc_context(data_ac);
1868                 data_ac = NULL;
1869         }
1870         if (meta_ac) {
1871                 ocfs2_free_alloc_context(meta_ac);
1872                 meta_ac = NULL;
1873         }
1874 
1875         if (ret == -ENOSPC && try_free) {
1876                 /*
1877                  * Try to free some truncate log so that we can have enough
1878                  * clusters to allocate.
1879                  */
1880                 try_free = 0;
1881 
1882                 ret1 = ocfs2_try_to_free_truncate_log(osb, clusters_need);
1883                 if (ret1 == 1)
1884                         goto try_again;
1885 
1886                 if (ret1 < 0)
1887                         mlog_errno(ret1);
1888         }
1889 
1890         return ret;
1891 }
1892 
1893 static int ocfs2_write_begin(struct file *file, struct address_space *mapping,
1894                              loff_t pos, unsigned len, unsigned flags,
1895                              struct page **pagep, void **fsdata)
1896 {
1897         int ret;
1898         struct buffer_head *di_bh = NULL;
1899         struct inode *inode = mapping->host;
1900 
1901         ret = ocfs2_inode_lock(inode, &di_bh, 1);
1902         if (ret) {
1903                 mlog_errno(ret);
1904                 return ret;
1905         }
1906 
1907         /*
1908          * Take alloc sem here to prevent concurrent lookups. That way
1909          * the mapping, zeroing and tree manipulation within
1910          * ocfs2_write() will be safe against ->readpage(). This
1911          * should also serve to lock out allocation from a shared
1912          * writeable region.
1913          */
1914         down_write(&OCFS2_I(inode)->ip_alloc_sem);
1915 
1916         ret = ocfs2_write_begin_nolock(mapping, pos, len, OCFS2_WRITE_BUFFER,
1917                                        pagep, fsdata, di_bh, NULL);
1918         if (ret) {
1919                 mlog_errno(ret);
1920                 goto out_fail;
1921         }
1922 
1923         brelse(di_bh);
1924 
1925         return 0;
1926 
1927 out_fail:
1928         up_write(&OCFS2_I(inode)->ip_alloc_sem);
1929 
1930         brelse(di_bh);
1931         ocfs2_inode_unlock(inode, 1);
1932 
1933         return ret;
1934 }
1935 
1936 static void ocfs2_write_end_inline(struct inode *inode, loff_t pos,
1937                                    unsigned len, unsigned *copied,
1938                                    struct ocfs2_dinode *di,
1939                                    struct ocfs2_write_ctxt *wc)
1940 {
1941         void *kaddr;
1942 
1943         if (unlikely(*copied < len)) {
1944                 if (!PageUptodate(wc->w_target_page)) {
1945                         *copied = 0;
1946                         return;
1947                 }
1948         }
1949 
1950         kaddr = kmap_atomic(wc->w_target_page);
1951         memcpy(di->id2.i_data.id_data + pos, kaddr + pos, *copied);
1952         kunmap_atomic(kaddr);
1953 
1954         trace_ocfs2_write_end_inline(
1955              (unsigned long long)OCFS2_I(inode)->ip_blkno,
1956              (unsigned long long)pos, *copied,
1957              le16_to_cpu(di->id2.i_data.id_count),
1958              le16_to_cpu(di->i_dyn_features));
1959 }
1960 
1961 int ocfs2_write_end_nolock(struct address_space *mapping,
1962                            loff_t pos, unsigned len, unsigned copied, void *fsdata)
1963 {
1964         int i, ret;
1965         unsigned from, to, start = pos & (PAGE_SIZE - 1);
1966         struct inode *inode = mapping->host;
1967         struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
1968         struct ocfs2_write_ctxt *wc = fsdata;
1969         struct ocfs2_dinode *di = (struct ocfs2_dinode *)wc->w_di_bh->b_data;
1970         handle_t *handle = wc->w_handle;
1971         struct page *tmppage;
1972 
1973         BUG_ON(!list_empty(&wc->w_unwritten_list));
1974 
1975         if (handle) {
1976                 ret = ocfs2_journal_access_di(handle, INODE_CACHE(inode),
1977                                 wc->w_di_bh, OCFS2_JOURNAL_ACCESS_WRITE);
1978                 if (ret) {
1979                         copied = ret;
1980                         mlog_errno(ret);
1981                         goto out;
1982                 }
1983         }
1984 
1985         if (OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL) {
1986                 ocfs2_write_end_inline(inode, pos, len, &copied, di, wc);
1987                 goto out_write_size;
1988         }
1989 
1990         if (unlikely(copied < len) && wc->w_target_page) {
1991                 if (!PageUptodate(wc->w_target_page))
1992                         copied = 0;
1993 
1994                 ocfs2_zero_new_buffers(wc->w_target_page, start+copied,
1995                                        start+len);
1996         }
1997         if (wc->w_target_page)
1998                 flush_dcache_page(wc->w_target_page);
1999 
2000         for(i = 0; i < wc->w_num_pages; i++) {
2001                 tmppage = wc->w_pages[i];
2002 
2003                 /* This is the direct io target page. */
2004                 if (tmppage == NULL)
2005                         continue;
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_SIZE ||
2012                                to > PAGE_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_SIZE;
2022                 }
2023 
2024                 if (page_has_buffers(tmppage)) {
2025                         if (handle && ocfs2_should_order_data(inode))
2026                                 ocfs2_jbd2_file_inode(handle, inode);
2027                         block_commit_write(tmppage, from, to);
2028                 }
2029         }
2030 
2031 out_write_size:
2032         /* Direct io do not update i_size here. */
2033         if (wc->w_type != OCFS2_WRITE_DIRECT) {
2034                 pos += copied;
2035                 if (pos > i_size_read(inode)) {
2036                         i_size_write(inode, pos);
2037                         mark_inode_dirty(inode);
2038                 }
2039                 inode->i_blocks = ocfs2_inode_sector_count(inode);
2040                 di->i_size = cpu_to_le64((u64)i_size_read(inode));
2041                 inode->i_mtime = inode->i_ctime = current_time(inode);
2042                 di->i_mtime = di->i_ctime = cpu_to_le64(inode->i_mtime.tv_sec);
2043                 di->i_mtime_nsec = di->i_ctime_nsec = cpu_to_le32(inode->i_mtime.tv_nsec);
2044                 ocfs2_update_inode_fsync_trans(handle, inode, 1);
2045         }
2046         if (handle)
2047                 ocfs2_journal_dirty(handle, wc->w_di_bh);
2048 
2049 out:
2050         /* unlock pages before dealloc since it needs acquiring j_trans_barrier
2051          * lock, or it will cause a deadlock since journal commit threads holds
2052          * this lock and will ask for the page lock when flushing the data.
2053          * put it here to preserve the unlock order.
2054          */
2055         ocfs2_unlock_pages(wc);
2056 
2057         if (handle)
2058                 ocfs2_commit_trans(osb, handle);
2059 
2060         ocfs2_run_deallocs(osb, &wc->w_dealloc);
2061 
2062         brelse(wc->w_di_bh);
2063         kfree(wc);
2064 
2065         return copied;
2066 }
2067 
2068 static int ocfs2_write_end(struct file *file, struct address_space *mapping,
2069                            loff_t pos, unsigned len, unsigned copied,
2070                            struct page *page, void *fsdata)
2071 {
2072         int ret;
2073         struct inode *inode = mapping->host;
2074 
2075         ret = ocfs2_write_end_nolock(mapping, pos, len, copied, fsdata);
2076 
2077         up_write(&OCFS2_I(inode)->ip_alloc_sem);
2078         ocfs2_inode_unlock(inode, 1);
2079 
2080         return ret;
2081 }
2082 
2083 struct ocfs2_dio_write_ctxt {
2084         struct list_head        dw_zero_list;
2085         unsigned                dw_zero_count;
2086         int                     dw_orphaned;
2087         pid_t                   dw_writer_pid;
2088 };
2089 
2090 static struct ocfs2_dio_write_ctxt *
2091 ocfs2_dio_alloc_write_ctx(struct buffer_head *bh, int *alloc)
2092 {
2093         struct ocfs2_dio_write_ctxt *dwc = NULL;
2094 
2095         if (bh->b_private)
2096                 return bh->b_private;
2097 
2098         dwc = kmalloc(sizeof(struct ocfs2_dio_write_ctxt), GFP_NOFS);
2099         if (dwc == NULL)
2100                 return NULL;
2101         INIT_LIST_HEAD(&dwc->dw_zero_list);
2102         dwc->dw_zero_count = 0;
2103         dwc->dw_orphaned = 0;
2104         dwc->dw_writer_pid = task_pid_nr(current);
2105         bh->b_private = dwc;
2106         *alloc = 1;
2107 
2108         return dwc;
2109 }
2110 
2111 static void ocfs2_dio_free_write_ctx(struct inode *inode,
2112                                      struct ocfs2_dio_write_ctxt *dwc)
2113 {
2114         ocfs2_free_unwritten_list(inode, &dwc->dw_zero_list);
2115         kfree(dwc);
2116 }
2117 
2118 /*
2119  * TODO: Make this into a generic get_blocks function.
2120  *
2121  * From do_direct_io in direct-io.c:
2122  *  "So what we do is to permit the ->get_blocks function to populate
2123  *   bh.b_size with the size of IO which is permitted at this offset and
2124  *   this i_blkbits."
2125  *
2126  * This function is called directly from get_more_blocks in direct-io.c.
2127  *
2128  * called like this: dio->get_blocks(dio->inode, fs_startblk,
2129  *                                      fs_count, map_bh, dio->rw == WRITE);
2130  */
2131 static int ocfs2_dio_get_block(struct inode *inode, sector_t iblock,
2132                                struct buffer_head *bh_result, int create)
2133 {
2134         struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
2135         struct ocfs2_inode_info *oi = OCFS2_I(inode);
2136         struct ocfs2_write_ctxt *wc;
2137         struct ocfs2_write_cluster_desc *desc = NULL;
2138         struct ocfs2_dio_write_ctxt *dwc = NULL;
2139         struct buffer_head *di_bh = NULL;
2140         u64 p_blkno;
2141         loff_t pos = iblock << inode->i_sb->s_blocksize_bits;
2142         unsigned len, total_len = bh_result->b_size;
2143         int ret = 0, first_get_block = 0;
2144 
2145         len = osb->s_clustersize - (pos & (osb->s_clustersize - 1));
2146         len = min(total_len, len);
2147 
2148         mlog(0, "get block of %lu at %llu:%u req %u\n",
2149                         inode->i_ino, pos, len, total_len);
2150 
2151         /*
2152          * Because we need to change file size in ocfs2_dio_end_io_write(), or
2153          * we may need to add it to orphan dir. So can not fall to fast path
2154          * while file size will be changed.
2155          */
2156         if (pos + total_len <= i_size_read(inode)) {
2157                 down_read(&oi->ip_alloc_sem);
2158                 /* This is the fast path for re-write. */
2159                 ret = ocfs2_get_block(inode, iblock, bh_result, create);
2160 
2161                 up_read(&oi->ip_alloc_sem);
2162 
2163                 if (buffer_mapped(bh_result) &&
2164                     !buffer_new(bh_result) &&
2165                     ret == 0)
2166                         goto out;
2167 
2168                 /* Clear state set by ocfs2_get_block. */
2169                 bh_result->b_state = 0;
2170         }
2171 
2172         dwc = ocfs2_dio_alloc_write_ctx(bh_result, &first_get_block);
2173         if (unlikely(dwc == NULL)) {
2174                 ret = -ENOMEM;
2175                 mlog_errno(ret);
2176                 goto out;
2177         }
2178 
2179         if (ocfs2_clusters_for_bytes(inode->i_sb, pos + total_len) >
2180             ocfs2_clusters_for_bytes(inode->i_sb, i_size_read(inode)) &&
2181             !dwc->dw_orphaned) {
2182                 /*
2183                  * when we are going to alloc extents beyond file size, add the
2184                  * inode to orphan dir, so we can recall those spaces when
2185                  * system crashed during write.
2186                  */
2187                 ret = ocfs2_add_inode_to_orphan(osb, inode);
2188                 if (ret < 0) {
2189                         mlog_errno(ret);
2190                         goto out;
2191                 }
2192                 dwc->dw_orphaned = 1;
2193         }
2194 
2195         ret = ocfs2_inode_lock(inode, &di_bh, 1);
2196         if (ret) {
2197                 mlog_errno(ret);
2198                 goto out;
2199         }
2200 
2201         down_write(&oi->ip_alloc_sem);
2202 
2203         if (first_get_block) {
2204                 if (ocfs2_sparse_alloc(OCFS2_SB(inode->i_sb)))
2205                         ret = ocfs2_zero_tail(inode, di_bh, pos);
2206                 else
2207                         ret = ocfs2_expand_nonsparse_inode(inode, di_bh, pos,
2208                                                            total_len, NULL);
2209                 if (ret < 0) {
2210                         mlog_errno(ret);
2211                         goto unlock;
2212                 }
2213         }
2214 
2215         ret = ocfs2_write_begin_nolock(inode->i_mapping, pos, len,
2216                                        OCFS2_WRITE_DIRECT, NULL,
2217                                        (void **)&wc, di_bh, NULL);
2218         if (ret) {
2219                 mlog_errno(ret);
2220                 goto unlock;
2221         }
2222 
2223         desc = &wc->w_desc[0];
2224 
2225         p_blkno = ocfs2_clusters_to_blocks(inode->i_sb, desc->c_phys);
2226         BUG_ON(p_blkno == 0);
2227         p_blkno += iblock & (u64)(ocfs2_clusters_to_blocks(inode->i_sb, 1) - 1);
2228 
2229         map_bh(bh_result, inode->i_sb, p_blkno);
2230         bh_result->b_size = len;
2231         if (desc->c_needs_zero)
2232                 set_buffer_new(bh_result);
2233 
2234         /* May sleep in end_io. It should not happen in a irq context. So defer
2235          * it to dio work queue. */
2236         set_buffer_defer_completion(bh_result);
2237 
2238         if (!list_empty(&wc->w_unwritten_list)) {
2239                 struct ocfs2_unwritten_extent *ue = NULL;
2240 
2241                 ue = list_first_entry(&wc->w_unwritten_list,
2242                                       struct ocfs2_unwritten_extent,
2243                                       ue_node);
2244                 BUG_ON(ue->ue_cpos != desc->c_cpos);
2245                 /* The physical address may be 0, fill it. */
2246                 ue->ue_phys = desc->c_phys;
2247 
2248                 list_splice_tail_init(&wc->w_unwritten_list, &dwc->dw_zero_list);
2249                 dwc->dw_zero_count++;
2250         }
2251 
2252         ret = ocfs2_write_end_nolock(inode->i_mapping, pos, len, len, wc);
2253         BUG_ON(ret != len);
2254         ret = 0;
2255 unlock:
2256         up_write(&oi->ip_alloc_sem);
2257         ocfs2_inode_unlock(inode, 1);
2258         brelse(di_bh);
2259 out:
2260         if (ret < 0)
2261                 ret = -EIO;
2262         return ret;
2263 }
2264 
2265 static int ocfs2_dio_end_io_write(struct inode *inode,
2266                                   struct ocfs2_dio_write_ctxt *dwc,
2267                                   loff_t offset,
2268                                   ssize_t bytes)
2269 {
2270         struct ocfs2_cached_dealloc_ctxt dealloc;
2271         struct ocfs2_extent_tree et;
2272         struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
2273         struct ocfs2_inode_info *oi = OCFS2_I(inode);
2274         struct ocfs2_unwritten_extent *ue = NULL;
2275         struct buffer_head *di_bh = NULL;
2276         struct ocfs2_dinode *di;
2277         struct ocfs2_alloc_context *data_ac = NULL;
2278         struct ocfs2_alloc_context *meta_ac = NULL;
2279         handle_t *handle = NULL;
2280         loff_t end = offset + bytes;
2281         int ret = 0, credits = 0, locked = 0;
2282 
2283         ocfs2_init_dealloc_ctxt(&dealloc);
2284 
2285         /* We do clear unwritten, delete orphan, change i_size here. If neither
2286          * of these happen, we can skip all this. */
2287         if (list_empty(&dwc->dw_zero_list) &&
2288             end <= i_size_read(inode) &&
2289             !dwc->dw_orphaned)
2290                 goto out;
2291 
2292         /* ocfs2_file_write_iter will get i_mutex, so we need not lock if we
2293          * are in that context. */
2294         if (dwc->dw_writer_pid != task_pid_nr(current)) {
2295                 inode_lock(inode);
2296                 locked = 1;
2297         }
2298 
2299         ret = ocfs2_inode_lock(inode, &di_bh, 1);
2300         if (ret < 0) {
2301                 mlog_errno(ret);
2302                 goto out;
2303         }
2304 
2305         down_write(&oi->ip_alloc_sem);
2306 
2307         /* Delete orphan before acquire i_mutex. */
2308         if (dwc->dw_orphaned) {
2309                 BUG_ON(dwc->dw_writer_pid != task_pid_nr(current));
2310 
2311                 end = end > i_size_read(inode) ? end : 0;
2312 
2313                 ret = ocfs2_del_inode_from_orphan(osb, inode, di_bh,
2314                                 !!end, end);
2315                 if (ret < 0)
2316                         mlog_errno(ret);
2317         }
2318 
2319         di = (struct ocfs2_dinode *)di_bh->b_data;
2320 
2321         ocfs2_init_dinode_extent_tree(&et, INODE_CACHE(inode), di_bh);
2322 
2323         ret = ocfs2_lock_allocators(inode, &et, 0, dwc->dw_zero_count*2,
2324                                     &data_ac, &meta_ac);
2325         if (ret) {
2326                 mlog_errno(ret);
2327                 goto unlock;
2328         }
2329 
2330         credits = ocfs2_calc_extend_credits(inode->i_sb, &di->id2.i_list);
2331 
2332         handle = ocfs2_start_trans(osb, credits);
2333         if (IS_ERR(handle)) {
2334                 ret = PTR_ERR(handle);
2335                 mlog_errno(ret);
2336                 goto unlock;
2337         }
2338         ret = ocfs2_journal_access_di(handle, INODE_CACHE(inode), di_bh,
2339                                       OCFS2_JOURNAL_ACCESS_WRITE);
2340         if (ret) {
2341                 mlog_errno(ret);
2342                 goto commit;
2343         }
2344 
2345         list_for_each_entry(ue, &dwc->dw_zero_list, ue_node) {
2346                 ret = ocfs2_mark_extent_written(inode, &et, handle,
2347                                                 ue->ue_cpos, 1,
2348                                                 ue->ue_phys,
2349                                                 meta_ac, &dealloc);
2350                 if (ret < 0) {
2351                         mlog_errno(ret);
2352                         break;
2353                 }
2354         }
2355 
2356         if (end > i_size_read(inode)) {
2357                 ret = ocfs2_set_inode_size(handle, inode, di_bh, end);
2358                 if (ret < 0)
2359                         mlog_errno(ret);
2360         }
2361 commit:
2362         ocfs2_commit_trans(osb, handle);
2363 unlock:
2364         up_write(&oi->ip_alloc_sem);
2365         ocfs2_inode_unlock(inode, 1);
2366         brelse(di_bh);
2367 out:
2368         if (data_ac)
2369                 ocfs2_free_alloc_context(data_ac);
2370         if (meta_ac)
2371                 ocfs2_free_alloc_context(meta_ac);
2372         ocfs2_run_deallocs(osb, &dealloc);
2373         if (locked)
2374                 inode_unlock(inode);
2375         ocfs2_dio_free_write_ctx(inode, dwc);
2376 
2377         return ret;
2378 }
2379 
2380 /*
2381  * ocfs2_dio_end_io is called by the dio core when a dio is finished.  We're
2382  * particularly interested in the aio/dio case.  We use the rw_lock DLM lock
2383  * to protect io on one node from truncation on another.
2384  */
2385 static int ocfs2_dio_end_io(struct kiocb *iocb,
2386                             loff_t offset,
2387                             ssize_t bytes,
2388                             void *private)
2389 {
2390         struct inode *inode = file_inode(iocb->ki_filp);
2391         int level;
2392         int ret = 0;
2393 
2394         /* this io's submitter should not have unlocked this before we could */
2395         BUG_ON(!ocfs2_iocb_is_rw_locked(iocb));
2396 
2397         if (bytes > 0 && private)
2398                 ret = ocfs2_dio_end_io_write(inode, private, offset, bytes);
2399 
2400         ocfs2_iocb_clear_rw_locked(iocb);
2401 
2402         level = ocfs2_iocb_rw_locked_level(iocb);
2403         ocfs2_rw_unlock(inode, level);
2404         return ret;
2405 }
2406 
2407 static ssize_t ocfs2_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
2408 {
2409         struct file *file = iocb->ki_filp;
2410         struct inode *inode = file->f_mapping->host;
2411         struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
2412         get_block_t *get_block;
2413 
2414         /*
2415          * Fallback to buffered I/O if we see an inode without
2416          * extents.
2417          */
2418         if (OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL)
2419                 return 0;
2420 
2421         /* Fallback to buffered I/O if we do not support append dio. */
2422         if (iocb->ki_pos + iter->count > i_size_read(inode) &&
2423             !ocfs2_supports_append_dio(osb))
2424                 return 0;
2425 
2426         if (iov_iter_rw(iter) == READ)
2427                 get_block = ocfs2_get_block;
2428         else
2429                 get_block = ocfs2_dio_get_block;
2430 
2431         return __blockdev_direct_IO(iocb, inode, inode->i_sb->s_bdev,
2432                                     iter, get_block,
2433                                     ocfs2_dio_end_io, NULL, 0);
2434 }
2435 
2436 const struct address_space_operations ocfs2_aops = {
2437         .readpage               = ocfs2_readpage,
2438         .readpages              = ocfs2_readpages,
2439         .writepage              = ocfs2_writepage,
2440         .write_begin            = ocfs2_write_begin,
2441         .write_end              = ocfs2_write_end,
2442         .bmap                   = ocfs2_bmap,
2443         .direct_IO              = ocfs2_direct_IO,
2444         .invalidatepage         = block_invalidatepage,
2445         .releasepage            = ocfs2_releasepage,
2446         .migratepage            = buffer_migrate_page,
2447         .is_partially_uptodate  = block_is_partially_uptodate,
2448         .error_remove_page      = generic_error_remove_page,
2449 };
2450 

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