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[linux-2.6] / fs / ocfs2 / aops.c
1 /* -*- mode: c; c-basic-offset: 8; -*-
2  * vim: noexpandtab sw=8 ts=8 sts=0:
3  *
4  * Copyright (C) 2002, 2004 Oracle.  All rights reserved.
5  *
6  * This program is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU General Public
8  * License as published by the Free Software Foundation; either
9  * version 2 of the License, or (at your option) any later version.
10  *
11  * This program is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
14  * General Public License for more details.
15  *
16  * You should have received a copy of the GNU General Public
17  * License along with this program; if not, write to the
18  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
19  * Boston, MA 021110-1307, USA.
20  */
21
22 #include <linux/fs.h>
23 #include <linux/slab.h>
24 #include <linux/highmem.h>
25 #include <linux/pagemap.h>
26 #include <asm/byteorder.h>
27
28 #define MLOG_MASK_PREFIX ML_FILE_IO
29 #include <cluster/masklog.h>
30
31 #include "ocfs2.h"
32
33 #include "alloc.h"
34 #include "aops.h"
35 #include "dlmglue.h"
36 #include "extent_map.h"
37 #include "file.h"
38 #include "inode.h"
39 #include "journal.h"
40 #include "super.h"
41 #include "symlink.h"
42
43 #include "buffer_head_io.h"
44
45 static int ocfs2_symlink_get_block(struct inode *inode, sector_t iblock,
46                                    struct buffer_head *bh_result, int create)
47 {
48         int err = -EIO;
49         int status;
50         struct ocfs2_dinode *fe = NULL;
51         struct buffer_head *bh = NULL;
52         struct buffer_head *buffer_cache_bh = NULL;
53         struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
54         void *kaddr;
55
56         mlog_entry("(0x%p, %llu, 0x%p, %d)\n", inode,
57                    (unsigned long long)iblock, bh_result, create);
58
59         BUG_ON(ocfs2_inode_is_fast_symlink(inode));
60
61         if ((iblock << inode->i_sb->s_blocksize_bits) > PATH_MAX + 1) {
62                 mlog(ML_ERROR, "block offset > PATH_MAX: %llu",
63                      (unsigned long long)iblock);
64                 goto bail;
65         }
66
67         status = ocfs2_read_block(OCFS2_SB(inode->i_sb),
68                                   OCFS2_I(inode)->ip_blkno,
69                                   &bh, OCFS2_BH_CACHED, inode);
70         if (status < 0) {
71                 mlog_errno(status);
72                 goto bail;
73         }
74         fe = (struct ocfs2_dinode *) bh->b_data;
75
76         if (!OCFS2_IS_VALID_DINODE(fe)) {
77                 mlog(ML_ERROR, "Invalid dinode #%"MLFu64": signature = %.*s\n",
78                      fe->i_blkno, 7, fe->i_signature);
79                 goto bail;
80         }
81
82         if ((u64)iblock >= ocfs2_clusters_to_blocks(inode->i_sb,
83                                                     le32_to_cpu(fe->i_clusters))) {
84                 mlog(ML_ERROR, "block offset is outside the allocated size: "
85                      "%llu\n", (unsigned long long)iblock);
86                 goto bail;
87         }
88
89         /* We don't use the page cache to create symlink data, so if
90          * need be, copy it over from the buffer cache. */
91         if (!buffer_uptodate(bh_result) && ocfs2_inode_is_new(inode)) {
92                 u64 blkno = le64_to_cpu(fe->id2.i_list.l_recs[0].e_blkno) +
93                             iblock;
94                 buffer_cache_bh = sb_getblk(osb->sb, blkno);
95                 if (!buffer_cache_bh) {
96                         mlog(ML_ERROR, "couldn't getblock for symlink!\n");
97                         goto bail;
98                 }
99
100                 /* we haven't locked out transactions, so a commit
101                  * could've happened. Since we've got a reference on
102                  * the bh, even if it commits while we're doing the
103                  * copy, the data is still good. */
104                 if (buffer_jbd(buffer_cache_bh)
105                     && ocfs2_inode_is_new(inode)) {
106                         kaddr = kmap_atomic(bh_result->b_page, KM_USER0);
107                         if (!kaddr) {
108                                 mlog(ML_ERROR, "couldn't kmap!\n");
109                                 goto bail;
110                         }
111                         memcpy(kaddr + (bh_result->b_size * iblock),
112                                buffer_cache_bh->b_data,
113                                bh_result->b_size);
114                         kunmap_atomic(kaddr, KM_USER0);
115                         set_buffer_uptodate(bh_result);
116                 }
117                 brelse(buffer_cache_bh);
118         }
119
120         map_bh(bh_result, inode->i_sb,
121                le64_to_cpu(fe->id2.i_list.l_recs[0].e_blkno) + iblock);
122
123         err = 0;
124
125 bail:
126         if (bh)
127                 brelse(bh);
128
129         mlog_exit(err);
130         return err;
131 }
132
133 static int ocfs2_get_block(struct inode *inode, sector_t iblock,
134                            struct buffer_head *bh_result, int create)
135 {
136         int err = 0;
137         u64 p_blkno, past_eof;
138
139         mlog_entry("(0x%p, %llu, 0x%p, %d)\n", inode,
140                    (unsigned long long)iblock, bh_result, create);
141
142         if (OCFS2_I(inode)->ip_flags & OCFS2_INODE_SYSTEM_FILE)
143                 mlog(ML_NOTICE, "get_block on system inode 0x%p (%lu)\n",
144                      inode, inode->i_ino);
145
146         if (S_ISLNK(inode->i_mode)) {
147                 /* this always does I/O for some reason. */
148                 err = ocfs2_symlink_get_block(inode, iblock, bh_result, create);
149                 goto bail;
150         }
151
152         /* this can happen if another node truncs after our extend! */
153         spin_lock(&OCFS2_I(inode)->ip_lock);
154         if (iblock >= ocfs2_clusters_to_blocks(inode->i_sb,
155                                                OCFS2_I(inode)->ip_clusters))
156                 err = -EIO;
157         spin_unlock(&OCFS2_I(inode)->ip_lock);
158         if (err)
159                 goto bail;
160
161         err = ocfs2_extent_map_get_blocks(inode, iblock, 1, &p_blkno,
162                                           NULL);
163         if (err) {
164                 mlog(ML_ERROR, "Error %d from get_blocks(0x%p, %llu, 1, "
165                      "%"MLFu64", NULL)\n", err, inode,
166                      (unsigned long long)iblock, p_blkno);
167                 goto bail;
168         }
169
170         map_bh(bh_result, inode->i_sb, p_blkno);
171
172         if (bh_result->b_blocknr == 0) {
173                 err = -EIO;
174                 mlog(ML_ERROR, "iblock = %llu p_blkno = %"MLFu64" "
175                      "blkno=(%"MLFu64")\n", (unsigned long long)iblock,
176                      p_blkno, OCFS2_I(inode)->ip_blkno);
177         }
178
179         past_eof = ocfs2_blocks_for_bytes(inode->i_sb, i_size_read(inode));
180         mlog(0, "Inode %lu, past_eof = %"MLFu64"\n", inode->i_ino, past_eof);
181
182         if (create && (iblock >= past_eof))
183                 set_buffer_new(bh_result);
184
185 bail:
186         if (err < 0)
187                 err = -EIO;
188
189         mlog_exit(err);
190         return err;
191 }
192
193 static int ocfs2_readpage(struct file *file, struct page *page)
194 {
195         struct inode *inode = page->mapping->host;
196         loff_t start = (loff_t)page->index << PAGE_CACHE_SHIFT;
197         int ret, unlock = 1;
198
199         mlog_entry("(0x%p, %lu)\n", file, (page ? page->index : 0));
200
201         ret = ocfs2_meta_lock_with_page(inode, NULL, NULL, 0, page);
202         if (ret != 0) {
203                 if (ret == AOP_TRUNCATED_PAGE)
204                         unlock = 0;
205                 mlog_errno(ret);
206                 goto out;
207         }
208
209         down_read(&OCFS2_I(inode)->ip_alloc_sem);
210
211         /*
212          * i_size might have just been updated as we grabed the meta lock.  We
213          * might now be discovering a truncate that hit on another node.
214          * block_read_full_page->get_block freaks out if it is asked to read
215          * beyond the end of a file, so we check here.  Callers
216          * (generic_file_read, fault->nopage) are clever enough to check i_size
217          * and notice that the page they just read isn't needed.
218          *
219          * XXX sys_readahead() seems to get that wrong?
220          */
221         if (start >= i_size_read(inode)) {
222                 char *addr = kmap(page);
223                 memset(addr, 0, PAGE_SIZE);
224                 flush_dcache_page(page);
225                 kunmap(page);
226                 SetPageUptodate(page);
227                 ret = 0;
228                 goto out_alloc;
229         }
230
231         ret = ocfs2_data_lock_with_page(inode, 0, page);
232         if (ret != 0) {
233                 if (ret == AOP_TRUNCATED_PAGE)
234                         unlock = 0;
235                 mlog_errno(ret);
236                 goto out_alloc;
237         }
238
239         ret = block_read_full_page(page, ocfs2_get_block);
240         unlock = 0;
241
242         ocfs2_data_unlock(inode, 0);
243 out_alloc:
244         up_read(&OCFS2_I(inode)->ip_alloc_sem);
245         ocfs2_meta_unlock(inode, 0);
246 out:
247         if (unlock)
248                 unlock_page(page);
249         mlog_exit(ret);
250         return ret;
251 }
252
253 /* Note: Because we don't support holes, our allocation has
254  * already happened (allocation writes zeros to the file data)
255  * so we don't have to worry about ordered writes in
256  * ocfs2_writepage.
257  *
258  * ->writepage is called during the process of invalidating the page cache
259  * during blocked lock processing.  It can't block on any cluster locks
260  * to during block mapping.  It's relying on the fact that the block
261  * mapping can't have disappeared under the dirty pages that it is
262  * being asked to write back.
263  */
264 static int ocfs2_writepage(struct page *page, struct writeback_control *wbc)
265 {
266         int ret;
267
268         mlog_entry("(0x%p)\n", page);
269
270         ret = block_write_full_page(page, ocfs2_get_block, wbc);
271
272         mlog_exit(ret);
273
274         return ret;
275 }
276
277 /*
278  * ocfs2_prepare_write() can be an outer-most ocfs2 call when it is called
279  * from loopback.  It must be able to perform its own locking around
280  * ocfs2_get_block().
281  */
282 int ocfs2_prepare_write(struct file *file, struct page *page,
283                         unsigned from, unsigned to)
284 {
285         struct inode *inode = page->mapping->host;
286         int ret;
287
288         mlog_entry("(0x%p, 0x%p, %u, %u)\n", file, page, from, to);
289
290         ret = ocfs2_meta_lock_with_page(inode, NULL, NULL, 0, page);
291         if (ret != 0) {
292                 mlog_errno(ret);
293                 goto out;
294         }
295
296         down_read(&OCFS2_I(inode)->ip_alloc_sem);
297
298         ret = block_prepare_write(page, from, to, ocfs2_get_block);
299
300         up_read(&OCFS2_I(inode)->ip_alloc_sem);
301
302         ocfs2_meta_unlock(inode, 0);
303 out:
304         mlog_exit(ret);
305         return ret;
306 }
307
308 /* Taken from ext3. We don't necessarily need the full blown
309  * functionality yet, but IMHO it's better to cut and paste the whole
310  * thing so we can avoid introducing our own bugs (and easily pick up
311  * their fixes when they happen) --Mark */
312 static int walk_page_buffers(   handle_t *handle,
313                                 struct buffer_head *head,
314                                 unsigned from,
315                                 unsigned to,
316                                 int *partial,
317                                 int (*fn)(      handle_t *handle,
318                                                 struct buffer_head *bh))
319 {
320         struct buffer_head *bh;
321         unsigned block_start, block_end;
322         unsigned blocksize = head->b_size;
323         int err, ret = 0;
324         struct buffer_head *next;
325
326         for (   bh = head, block_start = 0;
327                 ret == 0 && (bh != head || !block_start);
328                 block_start = block_end, bh = next)
329         {
330                 next = bh->b_this_page;
331                 block_end = block_start + blocksize;
332                 if (block_end <= from || block_start >= to) {
333                         if (partial && !buffer_uptodate(bh))
334                                 *partial = 1;
335                         continue;
336                 }
337                 err = (*fn)(handle, bh);
338                 if (!ret)
339                         ret = err;
340         }
341         return ret;
342 }
343
344 struct ocfs2_journal_handle *ocfs2_start_walk_page_trans(struct inode *inode,
345                                                          struct page *page,
346                                                          unsigned from,
347                                                          unsigned to)
348 {
349         struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
350         struct ocfs2_journal_handle *handle = NULL;
351         int ret = 0;
352
353         handle = ocfs2_start_trans(osb, NULL, OCFS2_INODE_UPDATE_CREDITS);
354         if (!handle) {
355                 ret = -ENOMEM;
356                 mlog_errno(ret);
357                 goto out;
358         }
359
360         if (ocfs2_should_order_data(inode)) {
361                 ret = walk_page_buffers(handle->k_handle,
362                                         page_buffers(page),
363                                         from, to, NULL,
364                                         ocfs2_journal_dirty_data);
365                 if (ret < 0) 
366                         mlog_errno(ret);
367         }
368 out:
369         if (ret) {
370                 if (handle)
371                         ocfs2_commit_trans(handle);
372                 handle = ERR_PTR(ret);
373         }
374         return handle;
375 }
376
377 static int ocfs2_commit_write(struct file *file, struct page *page,
378                               unsigned from, unsigned to)
379 {
380         int ret, extending = 0, locklevel = 0;
381         loff_t new_i_size;
382         struct buffer_head *di_bh = NULL;
383         struct inode *inode = page->mapping->host;
384         struct ocfs2_journal_handle *handle = NULL;
385
386         mlog_entry("(0x%p, 0x%p, %u, %u)\n", file, page, from, to);
387
388         /* NOTE: ocfs2_file_aio_write has ensured that it's safe for
389          * us to sample inode->i_size here without the metadata lock:
390          *
391          * 1) We're currently holding the inode alloc lock, so no
392          *    nodes can change it underneath us.
393          *
394          * 2) We've had to take the metadata lock at least once
395          *    already to check for extending writes, hence insuring
396          *    that our current copy is also up to date.
397          */
398         new_i_size = ((loff_t)page->index << PAGE_CACHE_SHIFT) + to;
399         if (new_i_size > i_size_read(inode)) {
400                 extending = 1;
401                 locklevel = 1;
402         }
403
404         ret = ocfs2_meta_lock_with_page(inode, NULL, &di_bh, locklevel, page);
405         if (ret != 0) {
406                 mlog_errno(ret);
407                 goto out;
408         }
409
410         ret = ocfs2_data_lock_with_page(inode, 1, page);
411         if (ret != 0) {
412                 mlog_errno(ret);
413                 goto out_unlock_meta;
414         }
415
416         if (extending) {
417                 handle = ocfs2_start_walk_page_trans(inode, page, from, to);
418                 if (IS_ERR(handle)) {
419                         ret = PTR_ERR(handle);
420                         handle = NULL;
421                         goto out_unlock_data;
422                 }
423
424                 /* Mark our buffer early. We'd rather catch this error up here
425                  * as opposed to after a successful commit_write which would
426                  * require us to set back inode->i_size. */
427                 ret = ocfs2_journal_access(handle, inode, di_bh,
428                                            OCFS2_JOURNAL_ACCESS_WRITE);
429                 if (ret < 0) {
430                         mlog_errno(ret);
431                         goto out_commit;
432                 }
433         }
434
435         /* might update i_size */
436         ret = generic_commit_write(file, page, from, to);
437         if (ret < 0) {
438                 mlog_errno(ret);
439                 goto out_commit;
440         }
441
442         if (extending) {
443                 loff_t size = (u64) i_size_read(inode);
444                 struct ocfs2_dinode *di =
445                         (struct ocfs2_dinode *)di_bh->b_data;
446
447                 /* ocfs2_mark_inode_dirty is too heavy to use here. */
448                 inode->i_blocks = ocfs2_align_bytes_to_sectors(size);
449                 inode->i_ctime = inode->i_mtime = CURRENT_TIME;
450
451                 di->i_size = cpu_to_le64(size);
452                 di->i_ctime = di->i_mtime = 
453                                 cpu_to_le64(inode->i_mtime.tv_sec);
454                 di->i_ctime_nsec = di->i_mtime_nsec = 
455                                 cpu_to_le32(inode->i_mtime.tv_nsec);
456
457                 ret = ocfs2_journal_dirty(handle, di_bh);
458                 if (ret < 0) {
459                         mlog_errno(ret);
460                         goto out_commit;
461                 }
462         }
463
464         BUG_ON(extending && (i_size_read(inode) != new_i_size));
465
466 out_commit:
467         if (handle)
468                 ocfs2_commit_trans(handle);
469 out_unlock_data:
470         ocfs2_data_unlock(inode, 1);
471 out_unlock_meta:
472         ocfs2_meta_unlock(inode, locklevel);
473 out:
474         if (di_bh)
475                 brelse(di_bh);
476
477         mlog_exit(ret);
478         return ret;
479 }
480
481 static sector_t ocfs2_bmap(struct address_space *mapping, sector_t block)
482 {
483         sector_t status;
484         u64 p_blkno = 0;
485         int err = 0;
486         struct inode *inode = mapping->host;
487
488         mlog_entry("(block = %llu)\n", (unsigned long long)block);
489
490         /* We don't need to lock journal system files, since they aren't
491          * accessed concurrently from multiple nodes.
492          */
493         if (!INODE_JOURNAL(inode)) {
494                 err = ocfs2_meta_lock(inode, NULL, NULL, 0);
495                 if (err) {
496                         if (err != -ENOENT)
497                                 mlog_errno(err);
498                         goto bail;
499                 }
500                 down_read(&OCFS2_I(inode)->ip_alloc_sem);
501         }
502
503         err = ocfs2_extent_map_get_blocks(inode, block, 1, &p_blkno,
504                                           NULL);
505
506         if (!INODE_JOURNAL(inode)) {
507                 up_read(&OCFS2_I(inode)->ip_alloc_sem);
508                 ocfs2_meta_unlock(inode, 0);
509         }
510
511         if (err) {
512                 mlog(ML_ERROR, "get_blocks() failed, block = %llu\n",
513                      (unsigned long long)block);
514                 mlog_errno(err);
515                 goto bail;
516         }
517
518
519 bail:
520         status = err ? 0 : p_blkno;
521
522         mlog_exit((int)status);
523
524         return status;
525 }
526
527 /*
528  * TODO: Make this into a generic get_blocks function.
529  *
530  * From do_direct_io in direct-io.c:
531  *  "So what we do is to permit the ->get_blocks function to populate
532  *   bh.b_size with the size of IO which is permitted at this offset and
533  *   this i_blkbits."
534  *
535  * This function is called directly from get_more_blocks in direct-io.c.
536  *
537  * called like this: dio->get_blocks(dio->inode, fs_startblk,
538  *                                      fs_count, map_bh, dio->rw == WRITE);
539  */
540 static int ocfs2_direct_IO_get_blocks(struct inode *inode, sector_t iblock,
541                                      unsigned long max_blocks,
542                                      struct buffer_head *bh_result, int create)
543 {
544         int ret;
545         u64 vbo_max; /* file offset, max_blocks from iblock */
546         u64 p_blkno;
547         int contig_blocks;
548         unsigned char blocksize_bits;
549
550         if (!inode || !bh_result) {
551                 mlog(ML_ERROR, "inode or bh_result is null\n");
552                 return -EIO;
553         }
554
555         blocksize_bits = inode->i_sb->s_blocksize_bits;
556
557         /* This function won't even be called if the request isn't all
558          * nicely aligned and of the right size, so there's no need
559          * for us to check any of that. */
560
561         vbo_max = ((u64)iblock + max_blocks) << blocksize_bits;
562
563         spin_lock(&OCFS2_I(inode)->ip_lock);
564         if ((iblock + max_blocks) >
565             ocfs2_clusters_to_blocks(inode->i_sb,
566                                      OCFS2_I(inode)->ip_clusters)) {
567                 spin_unlock(&OCFS2_I(inode)->ip_lock);
568                 ret = -EIO;
569                 goto bail;
570         }
571         spin_unlock(&OCFS2_I(inode)->ip_lock);
572
573         /* This figures out the size of the next contiguous block, and
574          * our logical offset */
575         ret = ocfs2_extent_map_get_blocks(inode, iblock, 1, &p_blkno,
576                                           &contig_blocks);
577         if (ret) {
578                 mlog(ML_ERROR, "get_blocks() failed iblock=%llu\n",
579                      (unsigned long long)iblock);
580                 ret = -EIO;
581                 goto bail;
582         }
583
584         map_bh(bh_result, inode->i_sb, p_blkno);
585
586         /* make sure we don't map more than max_blocks blocks here as
587            that's all the kernel will handle at this point. */
588         if (max_blocks < contig_blocks)
589                 contig_blocks = max_blocks;
590         bh_result->b_size = contig_blocks << blocksize_bits;
591 bail:
592         return ret;
593 }
594
595 /* 
596  * ocfs2_dio_end_io is called by the dio core when a dio is finished.  We're
597  * particularly interested in the aio/dio case.  Like the core uses
598  * i_alloc_sem, we use the rw_lock DLM lock to protect io on one node from
599  * truncation on another.
600  */
601 static void ocfs2_dio_end_io(struct kiocb *iocb,
602                              loff_t offset,
603                              ssize_t bytes,
604                              void *private)
605 {
606         struct inode *inode = iocb->ki_filp->f_dentry->d_inode;
607
608         /* this io's submitter should not have unlocked this before we could */
609         BUG_ON(!ocfs2_iocb_is_rw_locked(iocb));
610         ocfs2_iocb_clear_rw_locked(iocb);
611         up_read(&inode->i_alloc_sem);
612         ocfs2_rw_unlock(inode, 0);
613 }
614
615 static ssize_t ocfs2_direct_IO(int rw,
616                                struct kiocb *iocb,
617                                const struct iovec *iov,
618                                loff_t offset,
619                                unsigned long nr_segs)
620 {
621         struct file *file = iocb->ki_filp;
622         struct inode *inode = file->f_dentry->d_inode->i_mapping->host;
623         int ret;
624
625         mlog_entry_void();
626         ret = blockdev_direct_IO_no_locking(rw, iocb, inode,
627                                             inode->i_sb->s_bdev, iov, offset,
628                                             nr_segs, 
629                                             ocfs2_direct_IO_get_blocks,
630                                             ocfs2_dio_end_io);
631         mlog_exit(ret);
632         return ret;
633 }
634
635 struct address_space_operations ocfs2_aops = {
636         .readpage       = ocfs2_readpage,
637         .writepage      = ocfs2_writepage,
638         .prepare_write  = ocfs2_prepare_write,
639         .commit_write   = ocfs2_commit_write,
640         .bmap           = ocfs2_bmap,
641         .sync_page      = block_sync_page,
642         .direct_IO      = ocfs2_direct_IO
643 };