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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * file.c - NTFS kernel file operations. Part of the Linux-NTFS project.
4 *
5 * Copyright (c) 2001-2015 Anton Altaparmakov and Tuxera Inc.
6 */
7
8#include <linux/backing-dev.h>
9#include <linux/buffer_head.h>
10#include <linux/gfp.h>
11#include <linux/pagemap.h>
12#include <linux/pagevec.h>
13#include <linux/sched/signal.h>
14#include <linux/swap.h>
15#include <linux/uio.h>
16#include <linux/writeback.h>
17
18#include <asm/page.h>
19#include <linux/uaccess.h>
20
21#include "attrib.h"
22#include "bitmap.h"
23#include "inode.h"
24#include "debug.h"
25#include "lcnalloc.h"
26#include "malloc.h"
27#include "mft.h"
28#include "ntfs.h"
29
30/**
31 * ntfs_file_open - called when an inode is about to be opened
32 * @vi: inode to be opened
33 * @filp: file structure describing the inode
34 *
35 * Limit file size to the page cache limit on architectures where unsigned long
36 * is 32-bits. This is the most we can do for now without overflowing the page
37 * cache page index. Doing it this way means we don't run into problems because
38 * of existing too large files. It would be better to allow the user to read
39 * the beginning of the file but I doubt very much anyone is going to hit this
40 * check on a 32-bit architecture, so there is no point in adding the extra
41 * complexity required to support this.
42 *
43 * On 64-bit architectures, the check is hopefully optimized away by the
44 * compiler.
45 *
46 * After the check passes, just call generic_file_open() to do its work.
47 */
48static int ntfs_file_open(struct inode *vi, struct file *filp)
49{
50 if (sizeof(unsigned long) < 8) {
51 if (i_size_read(vi) > MAX_LFS_FILESIZE)
52 return -EOVERFLOW;
53 }
54 return generic_file_open(vi, filp);
55}
56
57#ifdef NTFS_RW
58
59/**
60 * ntfs_attr_extend_initialized - extend the initialized size of an attribute
61 * @ni: ntfs inode of the attribute to extend
62 * @new_init_size: requested new initialized size in bytes
63 *
64 * Extend the initialized size of an attribute described by the ntfs inode @ni
65 * to @new_init_size bytes. This involves zeroing any non-sparse space between
66 * the old initialized size and @new_init_size both in the page cache and on
67 * disk (if relevant complete pages are already uptodate in the page cache then
68 * these are simply marked dirty).
69 *
70 * As a side-effect, the file size (vfs inode->i_size) may be incremented as,
71 * in the resident attribute case, it is tied to the initialized size and, in
72 * the non-resident attribute case, it may not fall below the initialized size.
73 *
74 * Note that if the attribute is resident, we do not need to touch the page
75 * cache at all. This is because if the page cache page is not uptodate we
76 * bring it uptodate later, when doing the write to the mft record since we
77 * then already have the page mapped. And if the page is uptodate, the
78 * non-initialized region will already have been zeroed when the page was
79 * brought uptodate and the region may in fact already have been overwritten
80 * with new data via mmap() based writes, so we cannot just zero it. And since
81 * POSIX specifies that the behaviour of resizing a file whilst it is mmap()ped
82 * is unspecified, we choose not to do zeroing and thus we do not need to touch
83 * the page at all. For a more detailed explanation see ntfs_truncate() in
84 * fs/ntfs/inode.c.
85 *
86 * Return 0 on success and -errno on error. In the case that an error is
87 * encountered it is possible that the initialized size will already have been
88 * incremented some way towards @new_init_size but it is guaranteed that if
89 * this is the case, the necessary zeroing will also have happened and that all
90 * metadata is self-consistent.
91 *
92 * Locking: i_mutex on the vfs inode corrseponsind to the ntfs inode @ni must be
93 * held by the caller.
94 */
95static int ntfs_attr_extend_initialized(ntfs_inode *ni, const s64 new_init_size)
96{
97 s64 old_init_size;
98 loff_t old_i_size;
99 pgoff_t index, end_index;
100 unsigned long flags;
101 struct inode *vi = VFS_I(ni);
102 ntfs_inode *base_ni;
103 MFT_RECORD *m = NULL;
104 ATTR_RECORD *a;
105 ntfs_attr_search_ctx *ctx = NULL;
106 struct address_space *mapping;
107 struct page *page = NULL;
108 u8 *kattr;
109 int err;
110 u32 attr_len;
111
112 read_lock_irqsave(&ni->size_lock, flags);
113 old_init_size = ni->initialized_size;
114 old_i_size = i_size_read(vi);
115 BUG_ON(new_init_size > ni->allocated_size);
116 read_unlock_irqrestore(&ni->size_lock, flags);
117 ntfs_debug("Entering for i_ino 0x%lx, attribute type 0x%x, "
118 "old_initialized_size 0x%llx, "
119 "new_initialized_size 0x%llx, i_size 0x%llx.",
120 vi->i_ino, (unsigned)le32_to_cpu(ni->type),
121 (unsigned long long)old_init_size,
122 (unsigned long long)new_init_size, old_i_size);
123 if (!NInoAttr(ni))
124 base_ni = ni;
125 else
126 base_ni = ni->ext.base_ntfs_ino;
127 /* Use goto to reduce indentation and we need the label below anyway. */
128 if (NInoNonResident(ni))
129 goto do_non_resident_extend;
130 BUG_ON(old_init_size != old_i_size);
131 m = map_mft_record(base_ni);
132 if (IS_ERR(m)) {
133 err = PTR_ERR(m);
134 m = NULL;
135 goto err_out;
136 }
137 ctx = ntfs_attr_get_search_ctx(base_ni, m);
138 if (unlikely(!ctx)) {
139 err = -ENOMEM;
140 goto err_out;
141 }
142 err = ntfs_attr_lookup(ni->type, ni->name, ni->name_len,
143 CASE_SENSITIVE, 0, NULL, 0, ctx);
144 if (unlikely(err)) {
145 if (err == -ENOENT)
146 err = -EIO;
147 goto err_out;
148 }
149 m = ctx->mrec;
150 a = ctx->attr;
151 BUG_ON(a->non_resident);
152 /* The total length of the attribute value. */
153 attr_len = le32_to_cpu(a->data.resident.value_length);
154 BUG_ON(old_i_size != (loff_t)attr_len);
155 /*
156 * Do the zeroing in the mft record and update the attribute size in
157 * the mft record.
158 */
159 kattr = (u8*)a + le16_to_cpu(a->data.resident.value_offset);
160 memset(kattr + attr_len, 0, new_init_size - attr_len);
161 a->data.resident.value_length = cpu_to_le32((u32)new_init_size);
162 /* Finally, update the sizes in the vfs and ntfs inodes. */
163 write_lock_irqsave(&ni->size_lock, flags);
164 i_size_write(vi, new_init_size);
165 ni->initialized_size = new_init_size;
166 write_unlock_irqrestore(&ni->size_lock, flags);
167 goto done;
168do_non_resident_extend:
169 /*
170 * If the new initialized size @new_init_size exceeds the current file
171 * size (vfs inode->i_size), we need to extend the file size to the
172 * new initialized size.
173 */
174 if (new_init_size > old_i_size) {
175 m = map_mft_record(base_ni);
176 if (IS_ERR(m)) {
177 err = PTR_ERR(m);
178 m = NULL;
179 goto err_out;
180 }
181 ctx = ntfs_attr_get_search_ctx(base_ni, m);
182 if (unlikely(!ctx)) {
183 err = -ENOMEM;
184 goto err_out;
185 }
186 err = ntfs_attr_lookup(ni->type, ni->name, ni->name_len,
187 CASE_SENSITIVE, 0, NULL, 0, ctx);
188 if (unlikely(err)) {
189 if (err == -ENOENT)
190 err = -EIO;
191 goto err_out;
192 }
193 m = ctx->mrec;
194 a = ctx->attr;
195 BUG_ON(!a->non_resident);
196 BUG_ON(old_i_size != (loff_t)
197 sle64_to_cpu(a->data.non_resident.data_size));
198 a->data.non_resident.data_size = cpu_to_sle64(new_init_size);
199 flush_dcache_mft_record_page(ctx->ntfs_ino);
200 mark_mft_record_dirty(ctx->ntfs_ino);
201 /* Update the file size in the vfs inode. */
202 i_size_write(vi, new_init_size);
203 ntfs_attr_put_search_ctx(ctx);
204 ctx = NULL;
205 unmap_mft_record(base_ni);
206 m = NULL;
207 }
208 mapping = vi->i_mapping;
209 index = old_init_size >> PAGE_SHIFT;
210 end_index = (new_init_size + PAGE_SIZE - 1) >> PAGE_SHIFT;
211 do {
212 /*
213 * Read the page. If the page is not present, this will zero
214 * the uninitialized regions for us.
215 */
216 page = read_mapping_page(mapping, index, NULL);
217 if (IS_ERR(page)) {
218 err = PTR_ERR(page);
219 goto init_err_out;
220 }
221 if (unlikely(PageError(page))) {
222 put_page(page);
223 err = -EIO;
224 goto init_err_out;
225 }
226 /*
227 * Update the initialized size in the ntfs inode. This is
228 * enough to make ntfs_writepage() work.
229 */
230 write_lock_irqsave(&ni->size_lock, flags);
231 ni->initialized_size = (s64)(index + 1) << PAGE_SHIFT;
232 if (ni->initialized_size > new_init_size)
233 ni->initialized_size = new_init_size;
234 write_unlock_irqrestore(&ni->size_lock, flags);
235 /* Set the page dirty so it gets written out. */
236 set_page_dirty(page);
237 put_page(page);
238 /*
239 * Play nice with the vm and the rest of the system. This is
240 * very much needed as we can potentially be modifying the
241 * initialised size from a very small value to a really huge
242 * value, e.g.
243 * f = open(somefile, O_TRUNC);
244 * truncate(f, 10GiB);
245 * seek(f, 10GiB);
246 * write(f, 1);
247 * And this would mean we would be marking dirty hundreds of
248 * thousands of pages or as in the above example more than
249 * two and a half million pages!
250 *
251 * TODO: For sparse pages could optimize this workload by using
252 * the FsMisc / MiscFs page bit as a "PageIsSparse" bit. This
253 * would be set in readpage for sparse pages and here we would
254 * not need to mark dirty any pages which have this bit set.
255 * The only caveat is that we have to clear the bit everywhere
256 * where we allocate any clusters that lie in the page or that
257 * contain the page.
258 *
259 * TODO: An even greater optimization would be for us to only
260 * call readpage() on pages which are not in sparse regions as
261 * determined from the runlist. This would greatly reduce the
262 * number of pages we read and make dirty in the case of sparse
263 * files.
264 */
265 balance_dirty_pages_ratelimited(mapping);
266 cond_resched();
267 } while (++index < end_index);
268 read_lock_irqsave(&ni->size_lock, flags);
269 BUG_ON(ni->initialized_size != new_init_size);
270 read_unlock_irqrestore(&ni->size_lock, flags);
271 /* Now bring in sync the initialized_size in the mft record. */
272 m = map_mft_record(base_ni);
273 if (IS_ERR(m)) {
274 err = PTR_ERR(m);
275 m = NULL;
276 goto init_err_out;
277 }
278 ctx = ntfs_attr_get_search_ctx(base_ni, m);
279 if (unlikely(!ctx)) {
280 err = -ENOMEM;
281 goto init_err_out;
282 }
283 err = ntfs_attr_lookup(ni->type, ni->name, ni->name_len,
284 CASE_SENSITIVE, 0, NULL, 0, ctx);
285 if (unlikely(err)) {
286 if (err == -ENOENT)
287 err = -EIO;
288 goto init_err_out;
289 }
290 m = ctx->mrec;
291 a = ctx->attr;
292 BUG_ON(!a->non_resident);
293 a->data.non_resident.initialized_size = cpu_to_sle64(new_init_size);
294done:
295 flush_dcache_mft_record_page(ctx->ntfs_ino);
296 mark_mft_record_dirty(ctx->ntfs_ino);
297 if (ctx)
298 ntfs_attr_put_search_ctx(ctx);
299 if (m)
300 unmap_mft_record(base_ni);
301 ntfs_debug("Done, initialized_size 0x%llx, i_size 0x%llx.",
302 (unsigned long long)new_init_size, i_size_read(vi));
303 return 0;
304init_err_out:
305 write_lock_irqsave(&ni->size_lock, flags);
306 ni->initialized_size = old_init_size;
307 write_unlock_irqrestore(&ni->size_lock, flags);
308err_out:
309 if (ctx)
310 ntfs_attr_put_search_ctx(ctx);
311 if (m)
312 unmap_mft_record(base_ni);
313 ntfs_debug("Failed. Returning error code %i.", err);
314 return err;
315}
316
317static ssize_t ntfs_prepare_file_for_write(struct kiocb *iocb,
318 struct iov_iter *from)
319{
320 loff_t pos;
321 s64 end, ll;
322 ssize_t err;
323 unsigned long flags;
324 struct file *file = iocb->ki_filp;
325 struct inode *vi = file_inode(file);
326 ntfs_inode *base_ni, *ni = NTFS_I(vi);
327 ntfs_volume *vol = ni->vol;
328
329 ntfs_debug("Entering for i_ino 0x%lx, attribute type 0x%x, pos "
330 "0x%llx, count 0x%zx.", vi->i_ino,
331 (unsigned)le32_to_cpu(ni->type),
332 (unsigned long long)iocb->ki_pos,
333 iov_iter_count(from));
334 err = generic_write_checks(iocb, from);
335 if (unlikely(err <= 0))
336 goto out;
337 /*
338 * All checks have passed. Before we start doing any writing we want
339 * to abort any totally illegal writes.
340 */
341 BUG_ON(NInoMstProtected(ni));
342 BUG_ON(ni->type != AT_DATA);
343 /* If file is encrypted, deny access, just like NT4. */
344 if (NInoEncrypted(ni)) {
345 /* Only $DATA attributes can be encrypted. */
346 /*
347 * Reminder for later: Encrypted files are _always_
348 * non-resident so that the content can always be encrypted.
349 */
350 ntfs_debug("Denying write access to encrypted file.");
351 err = -EACCES;
352 goto out;
353 }
354 if (NInoCompressed(ni)) {
355 /* Only unnamed $DATA attribute can be compressed. */
356 BUG_ON(ni->name_len);
357 /*
358 * Reminder for later: If resident, the data is not actually
359 * compressed. Only on the switch to non-resident does
360 * compression kick in. This is in contrast to encrypted files
361 * (see above).
362 */
363 ntfs_error(vi->i_sb, "Writing to compressed files is not "
364 "implemented yet. Sorry.");
365 err = -EOPNOTSUPP;
366 goto out;
367 }
368 base_ni = ni;
369 if (NInoAttr(ni))
370 base_ni = ni->ext.base_ntfs_ino;
371 err = file_remove_privs(file);
372 if (unlikely(err))
373 goto out;
374 /*
375 * Our ->update_time method always succeeds thus file_update_time()
376 * cannot fail either so there is no need to check the return code.
377 */
378 file_update_time(file);
379 pos = iocb->ki_pos;
380 /* The first byte after the last cluster being written to. */
381 end = (pos + iov_iter_count(from) + vol->cluster_size_mask) &
382 ~(u64)vol->cluster_size_mask;
383 /*
384 * If the write goes beyond the allocated size, extend the allocation
385 * to cover the whole of the write, rounded up to the nearest cluster.
386 */
387 read_lock_irqsave(&ni->size_lock, flags);
388 ll = ni->allocated_size;
389 read_unlock_irqrestore(&ni->size_lock, flags);
390 if (end > ll) {
391 /*
392 * Extend the allocation without changing the data size.
393 *
394 * Note we ensure the allocation is big enough to at least
395 * write some data but we do not require the allocation to be
396 * complete, i.e. it may be partial.
397 */
398 ll = ntfs_attr_extend_allocation(ni, end, -1, pos);
399 if (likely(ll >= 0)) {
400 BUG_ON(pos >= ll);
401 /* If the extension was partial truncate the write. */
402 if (end > ll) {
403 ntfs_debug("Truncating write to inode 0x%lx, "
404 "attribute type 0x%x, because "
405 "the allocation was only "
406 "partially extended.",
407 vi->i_ino, (unsigned)
408 le32_to_cpu(ni->type));
409 iov_iter_truncate(from, ll - pos);
410 }
411 } else {
412 err = ll;
413 read_lock_irqsave(&ni->size_lock, flags);
414 ll = ni->allocated_size;
415 read_unlock_irqrestore(&ni->size_lock, flags);
416 /* Perform a partial write if possible or fail. */
417 if (pos < ll) {
418 ntfs_debug("Truncating write to inode 0x%lx "
419 "attribute type 0x%x, because "
420 "extending the allocation "
421 "failed (error %d).",
422 vi->i_ino, (unsigned)
423 le32_to_cpu(ni->type),
424 (int)-err);
425 iov_iter_truncate(from, ll - pos);
426 } else {
427 if (err != -ENOSPC)
428 ntfs_error(vi->i_sb, "Cannot perform "
429 "write to inode "
430 "0x%lx, attribute "
431 "type 0x%x, because "
432 "extending the "
433 "allocation failed "
434 "(error %ld).",
435 vi->i_ino, (unsigned)
436 le32_to_cpu(ni->type),
437 (long)-err);
438 else
439 ntfs_debug("Cannot perform write to "
440 "inode 0x%lx, "
441 "attribute type 0x%x, "
442 "because there is not "
443 "space left.",
444 vi->i_ino, (unsigned)
445 le32_to_cpu(ni->type));
446 goto out;
447 }
448 }
449 }
450 /*
451 * If the write starts beyond the initialized size, extend it up to the
452 * beginning of the write and initialize all non-sparse space between
453 * the old initialized size and the new one. This automatically also
454 * increments the vfs inode->i_size to keep it above or equal to the
455 * initialized_size.
456 */
457 read_lock_irqsave(&ni->size_lock, flags);
458 ll = ni->initialized_size;
459 read_unlock_irqrestore(&ni->size_lock, flags);
460 if (pos > ll) {
461 /*
462 * Wait for ongoing direct i/o to complete before proceeding.
463 * New direct i/o cannot start as we hold i_mutex.
464 */
465 inode_dio_wait(vi);
466 err = ntfs_attr_extend_initialized(ni, pos);
467 if (unlikely(err < 0))
468 ntfs_error(vi->i_sb, "Cannot perform write to inode "
469 "0x%lx, attribute type 0x%x, because "
470 "extending the initialized size "
471 "failed (error %d).", vi->i_ino,
472 (unsigned)le32_to_cpu(ni->type),
473 (int)-err);
474 }
475out:
476 return err;
477}
478
479/**
480 * __ntfs_grab_cache_pages - obtain a number of locked pages
481 * @mapping: address space mapping from which to obtain page cache pages
482 * @index: starting index in @mapping at which to begin obtaining pages
483 * @nr_pages: number of page cache pages to obtain
484 * @pages: array of pages in which to return the obtained page cache pages
485 * @cached_page: allocated but as yet unused page
486 *
487 * Obtain @nr_pages locked page cache pages from the mapping @mapping and
488 * starting at index @index.
489 *
490 * If a page is newly created, add it to lru list
491 *
492 * Note, the page locks are obtained in ascending page index order.
493 */
494static inline int __ntfs_grab_cache_pages(struct address_space *mapping,
495 pgoff_t index, const unsigned nr_pages, struct page **pages,
496 struct page **cached_page)
497{
498 int err, nr;
499
500 BUG_ON(!nr_pages);
501 err = nr = 0;
502 do {
503 pages[nr] = find_get_page_flags(mapping, index, FGP_LOCK |
504 FGP_ACCESSED);
505 if (!pages[nr]) {
506 if (!*cached_page) {
507 *cached_page = page_cache_alloc(mapping);
508 if (unlikely(!*cached_page)) {
509 err = -ENOMEM;
510 goto err_out;
511 }
512 }
513 err = add_to_page_cache_lru(*cached_page, mapping,
514 index,
515 mapping_gfp_constraint(mapping, GFP_KERNEL));
516 if (unlikely(err)) {
517 if (err == -EEXIST)
518 continue;
519 goto err_out;
520 }
521 pages[nr] = *cached_page;
522 *cached_page = NULL;
523 }
524 index++;
525 nr++;
526 } while (nr < nr_pages);
527out:
528 return err;
529err_out:
530 while (nr > 0) {
531 unlock_page(pages[--nr]);
532 put_page(pages[nr]);
533 }
534 goto out;
535}
536
537static inline int ntfs_submit_bh_for_read(struct buffer_head *bh)
538{
539 lock_buffer(bh);
540 get_bh(bh);
541 bh->b_end_io = end_buffer_read_sync;
542 return submit_bh(REQ_OP_READ, 0, bh);
543}
544
545/**
546 * ntfs_prepare_pages_for_non_resident_write - prepare pages for receiving data
547 * @pages: array of destination pages
548 * @nr_pages: number of pages in @pages
549 * @pos: byte position in file at which the write begins
550 * @bytes: number of bytes to be written
551 *
552 * This is called for non-resident attributes from ntfs_file_buffered_write()
553 * with i_mutex held on the inode (@pages[0]->mapping->host). There are
554 * @nr_pages pages in @pages which are locked but not kmap()ped. The source
555 * data has not yet been copied into the @pages.
556 *
557 * Need to fill any holes with actual clusters, allocate buffers if necessary,
558 * ensure all the buffers are mapped, and bring uptodate any buffers that are
559 * only partially being written to.
560 *
561 * If @nr_pages is greater than one, we are guaranteed that the cluster size is
562 * greater than PAGE_SIZE, that all pages in @pages are entirely inside
563 * the same cluster and that they are the entirety of that cluster, and that
564 * the cluster is sparse, i.e. we need to allocate a cluster to fill the hole.
565 *
566 * i_size is not to be modified yet.
567 *
568 * Return 0 on success or -errno on error.
569 */
570static int ntfs_prepare_pages_for_non_resident_write(struct page **pages,
571 unsigned nr_pages, s64 pos, size_t bytes)
572{
573 VCN vcn, highest_vcn = 0, cpos, cend, bh_cpos, bh_cend;
574 LCN lcn;
575 s64 bh_pos, vcn_len, end, initialized_size;
576 sector_t lcn_block;
577 struct page *page;
578 struct inode *vi;
579 ntfs_inode *ni, *base_ni = NULL;
580 ntfs_volume *vol;
581 runlist_element *rl, *rl2;
582 struct buffer_head *bh, *head, *wait[2], **wait_bh = wait;
583 ntfs_attr_search_ctx *ctx = NULL;
584 MFT_RECORD *m = NULL;
585 ATTR_RECORD *a = NULL;
586 unsigned long flags;
587 u32 attr_rec_len = 0;
588 unsigned blocksize, u;
589 int err, mp_size;
590 bool rl_write_locked, was_hole, is_retry;
591 unsigned char blocksize_bits;
592 struct {
593 u8 runlist_merged:1;
594 u8 mft_attr_mapped:1;
595 u8 mp_rebuilt:1;
596 u8 attr_switched:1;
597 } status = { 0, 0, 0, 0 };
598
599 BUG_ON(!nr_pages);
600 BUG_ON(!pages);
601 BUG_ON(!*pages);
602 vi = pages[0]->mapping->host;
603 ni = NTFS_I(vi);
604 vol = ni->vol;
605 ntfs_debug("Entering for inode 0x%lx, attribute type 0x%x, start page "
606 "index 0x%lx, nr_pages 0x%x, pos 0x%llx, bytes 0x%zx.",
607 vi->i_ino, ni->type, pages[0]->index, nr_pages,
608 (long long)pos, bytes);
609 blocksize = vol->sb->s_blocksize;
610 blocksize_bits = vol->sb->s_blocksize_bits;
611 u = 0;
612 do {
613 page = pages[u];
614 BUG_ON(!page);
615 /*
616 * create_empty_buffers() will create uptodate/dirty buffers if
617 * the page is uptodate/dirty.
618 */
619 if (!page_has_buffers(page)) {
620 create_empty_buffers(page, blocksize, 0);
621 if (unlikely(!page_has_buffers(page)))
622 return -ENOMEM;
623 }
624 } while (++u < nr_pages);
625 rl_write_locked = false;
626 rl = NULL;
627 err = 0;
628 vcn = lcn = -1;
629 vcn_len = 0;
630 lcn_block = -1;
631 was_hole = false;
632 cpos = pos >> vol->cluster_size_bits;
633 end = pos + bytes;
634 cend = (end + vol->cluster_size - 1) >> vol->cluster_size_bits;
635 /*
636 * Loop over each page and for each page over each buffer. Use goto to
637 * reduce indentation.
638 */
639 u = 0;
640do_next_page:
641 page = pages[u];
642 bh_pos = (s64)page->index << PAGE_SHIFT;
643 bh = head = page_buffers(page);
644 do {
645 VCN cdelta;
646 s64 bh_end;
647 unsigned bh_cofs;
648
649 /* Clear buffer_new on all buffers to reinitialise state. */
650 if (buffer_new(bh))
651 clear_buffer_new(bh);
652 bh_end = bh_pos + blocksize;
653 bh_cpos = bh_pos >> vol->cluster_size_bits;
654 bh_cofs = bh_pos & vol->cluster_size_mask;
655 if (buffer_mapped(bh)) {
656 /*
657 * The buffer is already mapped. If it is uptodate,
658 * ignore it.
659 */
660 if (buffer_uptodate(bh))
661 continue;
662 /*
663 * The buffer is not uptodate. If the page is uptodate
664 * set the buffer uptodate and otherwise ignore it.
665 */
666 if (PageUptodate(page)) {
667 set_buffer_uptodate(bh);
668 continue;
669 }
670 /*
671 * Neither the page nor the buffer are uptodate. If
672 * the buffer is only partially being written to, we
673 * need to read it in before the write, i.e. now.
674 */
675 if ((bh_pos < pos && bh_end > pos) ||
676 (bh_pos < end && bh_end > end)) {
677 /*
678 * If the buffer is fully or partially within
679 * the initialized size, do an actual read.
680 * Otherwise, simply zero the buffer.
681 */
682 read_lock_irqsave(&ni->size_lock, flags);
683 initialized_size = ni->initialized_size;
684 read_unlock_irqrestore(&ni->size_lock, flags);
685 if (bh_pos < initialized_size) {
686 ntfs_submit_bh_for_read(bh);
687 *wait_bh++ = bh;
688 } else {
689 zero_user(page, bh_offset(bh),
690 blocksize);
691 set_buffer_uptodate(bh);
692 }
693 }
694 continue;
695 }
696 /* Unmapped buffer. Need to map it. */
697 bh->b_bdev = vol->sb->s_bdev;
698 /*
699 * If the current buffer is in the same clusters as the map
700 * cache, there is no need to check the runlist again. The
701 * map cache is made up of @vcn, which is the first cached file
702 * cluster, @vcn_len which is the number of cached file
703 * clusters, @lcn is the device cluster corresponding to @vcn,
704 * and @lcn_block is the block number corresponding to @lcn.
705 */
706 cdelta = bh_cpos - vcn;
707 if (likely(!cdelta || (cdelta > 0 && cdelta < vcn_len))) {
708map_buffer_cached:
709 BUG_ON(lcn < 0);
710 bh->b_blocknr = lcn_block +
711 (cdelta << (vol->cluster_size_bits -
712 blocksize_bits)) +
713 (bh_cofs >> blocksize_bits);
714 set_buffer_mapped(bh);
715 /*
716 * If the page is uptodate so is the buffer. If the
717 * buffer is fully outside the write, we ignore it if
718 * it was already allocated and we mark it dirty so it
719 * gets written out if we allocated it. On the other
720 * hand, if we allocated the buffer but we are not
721 * marking it dirty we set buffer_new so we can do
722 * error recovery.
723 */
724 if (PageUptodate(page)) {
725 if (!buffer_uptodate(bh))
726 set_buffer_uptodate(bh);
727 if (unlikely(was_hole)) {
728 /* We allocated the buffer. */
729 clean_bdev_bh_alias(bh);
730 if (bh_end <= pos || bh_pos >= end)
731 mark_buffer_dirty(bh);
732 else
733 set_buffer_new(bh);
734 }
735 continue;
736 }
737 /* Page is _not_ uptodate. */
738 if (likely(!was_hole)) {
739 /*
740 * Buffer was already allocated. If it is not
741 * uptodate and is only partially being written
742 * to, we need to read it in before the write,
743 * i.e. now.
744 */
745 if (!buffer_uptodate(bh) && bh_pos < end &&
746 bh_end > pos &&
747 (bh_pos < pos ||
748 bh_end > end)) {
749 /*
750 * If the buffer is fully or partially
751 * within the initialized size, do an
752 * actual read. Otherwise, simply zero
753 * the buffer.
754 */
755 read_lock_irqsave(&ni->size_lock,
756 flags);
757 initialized_size = ni->initialized_size;
758 read_unlock_irqrestore(&ni->size_lock,
759 flags);
760 if (bh_pos < initialized_size) {
761 ntfs_submit_bh_for_read(bh);
762 *wait_bh++ = bh;
763 } else {
764 zero_user(page, bh_offset(bh),
765 blocksize);
766 set_buffer_uptodate(bh);
767 }
768 }
769 continue;
770 }
771 /* We allocated the buffer. */
772 clean_bdev_bh_alias(bh);
773 /*
774 * If the buffer is fully outside the write, zero it,
775 * set it uptodate, and mark it dirty so it gets
776 * written out. If it is partially being written to,
777 * zero region surrounding the write but leave it to
778 * commit write to do anything else. Finally, if the
779 * buffer is fully being overwritten, do nothing.
780 */
781 if (bh_end <= pos || bh_pos >= end) {
782 if (!buffer_uptodate(bh)) {
783 zero_user(page, bh_offset(bh),
784 blocksize);
785 set_buffer_uptodate(bh);
786 }
787 mark_buffer_dirty(bh);
788 continue;
789 }
790 set_buffer_new(bh);
791 if (!buffer_uptodate(bh) &&
792 (bh_pos < pos || bh_end > end)) {
793 u8 *kaddr;
794 unsigned pofs;
795
796 kaddr = kmap_atomic(page);
797 if (bh_pos < pos) {
798 pofs = bh_pos & ~PAGE_MASK;
799 memset(kaddr + pofs, 0, pos - bh_pos);
800 }
801 if (bh_end > end) {
802 pofs = end & ~PAGE_MASK;
803 memset(kaddr + pofs, 0, bh_end - end);
804 }
805 kunmap_atomic(kaddr);
806 flush_dcache_page(page);
807 }
808 continue;
809 }
810 /*
811 * Slow path: this is the first buffer in the cluster. If it
812 * is outside allocated size and is not uptodate, zero it and
813 * set it uptodate.
814 */
815 read_lock_irqsave(&ni->size_lock, flags);
816 initialized_size = ni->allocated_size;
817 read_unlock_irqrestore(&ni->size_lock, flags);
818 if (bh_pos > initialized_size) {
819 if (PageUptodate(page)) {
820 if (!buffer_uptodate(bh))
821 set_buffer_uptodate(bh);
822 } else if (!buffer_uptodate(bh)) {
823 zero_user(page, bh_offset(bh), blocksize);
824 set_buffer_uptodate(bh);
825 }
826 continue;
827 }
828 is_retry = false;
829 if (!rl) {
830 down_read(&ni->runlist.lock);
831retry_remap:
832 rl = ni->runlist.rl;
833 }
834 if (likely(rl != NULL)) {
835 /* Seek to element containing target cluster. */
836 while (rl->length && rl[1].vcn <= bh_cpos)
837 rl++;
838 lcn = ntfs_rl_vcn_to_lcn(rl, bh_cpos);
839 if (likely(lcn >= 0)) {
840 /*
841 * Successful remap, setup the map cache and
842 * use that to deal with the buffer.
843 */
844 was_hole = false;
845 vcn = bh_cpos;
846 vcn_len = rl[1].vcn - vcn;
847 lcn_block = lcn << (vol->cluster_size_bits -
848 blocksize_bits);
849 cdelta = 0;
850 /*
851 * If the number of remaining clusters touched
852 * by the write is smaller or equal to the
853 * number of cached clusters, unlock the
854 * runlist as the map cache will be used from
855 * now on.
856 */
857 if (likely(vcn + vcn_len >= cend)) {
858 if (rl_write_locked) {
859 up_write(&ni->runlist.lock);
860 rl_write_locked = false;
861 } else
862 up_read(&ni->runlist.lock);
863 rl = NULL;
864 }
865 goto map_buffer_cached;
866 }
867 } else
868 lcn = LCN_RL_NOT_MAPPED;
869 /*
870 * If it is not a hole and not out of bounds, the runlist is
871 * probably unmapped so try to map it now.
872 */
873 if (unlikely(lcn != LCN_HOLE && lcn != LCN_ENOENT)) {
874 if (likely(!is_retry && lcn == LCN_RL_NOT_MAPPED)) {
875 /* Attempt to map runlist. */
876 if (!rl_write_locked) {
877 /*
878 * We need the runlist locked for
879 * writing, so if it is locked for
880 * reading relock it now and retry in
881 * case it changed whilst we dropped
882 * the lock.
883 */
884 up_read(&ni->runlist.lock);
885 down_write(&ni->runlist.lock);
886 rl_write_locked = true;
887 goto retry_remap;
888 }
889 err = ntfs_map_runlist_nolock(ni, bh_cpos,
890 NULL);
891 if (likely(!err)) {
892 is_retry = true;
893 goto retry_remap;
894 }
895 /*
896 * If @vcn is out of bounds, pretend @lcn is
897 * LCN_ENOENT. As long as the buffer is out
898 * of bounds this will work fine.
899 */
900 if (err == -ENOENT) {
901 lcn = LCN_ENOENT;
902 err = 0;
903 goto rl_not_mapped_enoent;
904 }
905 } else
906 err = -EIO;
907 /* Failed to map the buffer, even after retrying. */
908 bh->b_blocknr = -1;
909 ntfs_error(vol->sb, "Failed to write to inode 0x%lx, "
910 "attribute type 0x%x, vcn 0x%llx, "
911 "vcn offset 0x%x, because its "
912 "location on disk could not be "
913 "determined%s (error code %i).",
914 ni->mft_no, ni->type,
915 (unsigned long long)bh_cpos,
916 (unsigned)bh_pos &
917 vol->cluster_size_mask,
918 is_retry ? " even after retrying" : "",
919 err);
920 break;
921 }
922rl_not_mapped_enoent:
923 /*
924 * The buffer is in a hole or out of bounds. We need to fill
925 * the hole, unless the buffer is in a cluster which is not
926 * touched by the write, in which case we just leave the buffer
927 * unmapped. This can only happen when the cluster size is
928 * less than the page cache size.
929 */
930 if (unlikely(vol->cluster_size < PAGE_SIZE)) {
931 bh_cend = (bh_end + vol->cluster_size - 1) >>
932 vol->cluster_size_bits;
933 if ((bh_cend <= cpos || bh_cpos >= cend)) {
934 bh->b_blocknr = -1;
935 /*
936 * If the buffer is uptodate we skip it. If it
937 * is not but the page is uptodate, we can set
938 * the buffer uptodate. If the page is not
939 * uptodate, we can clear the buffer and set it
940 * uptodate. Whether this is worthwhile is
941 * debatable and this could be removed.
942 */
943 if (PageUptodate(page)) {
944 if (!buffer_uptodate(bh))
945 set_buffer_uptodate(bh);
946 } else if (!buffer_uptodate(bh)) {
947 zero_user(page, bh_offset(bh),
948 blocksize);
949 set_buffer_uptodate(bh);
950 }
951 continue;
952 }
953 }
954 /*
955 * Out of bounds buffer is invalid if it was not really out of
956 * bounds.
957 */
958 BUG_ON(lcn != LCN_HOLE);
959 /*
960 * We need the runlist locked for writing, so if it is locked
961 * for reading relock it now and retry in case it changed
962 * whilst we dropped the lock.
963 */
964 BUG_ON(!rl);
965 if (!rl_write_locked) {
966 up_read(&ni->runlist.lock);
967 down_write(&ni->runlist.lock);
968 rl_write_locked = true;
969 goto retry_remap;
970 }
971 /* Find the previous last allocated cluster. */
972 BUG_ON(rl->lcn != LCN_HOLE);
973 lcn = -1;
974 rl2 = rl;
975 while (--rl2 >= ni->runlist.rl) {
976 if (rl2->lcn >= 0) {
977 lcn = rl2->lcn + rl2->length;
978 break;
979 }
980 }
981 rl2 = ntfs_cluster_alloc(vol, bh_cpos, 1, lcn, DATA_ZONE,
982 false);
983 if (IS_ERR(rl2)) {
984 err = PTR_ERR(rl2);
985 ntfs_debug("Failed to allocate cluster, error code %i.",
986 err);
987 break;
988 }
989 lcn = rl2->lcn;
990 rl = ntfs_runlists_merge(ni->runlist.rl, rl2);
991 if (IS_ERR(rl)) {
992 err = PTR_ERR(rl);
993 if (err != -ENOMEM)
994 err = -EIO;
995 if (ntfs_cluster_free_from_rl(vol, rl2)) {
996 ntfs_error(vol->sb, "Failed to release "
997 "allocated cluster in error "
998 "code path. Run chkdsk to "
999 "recover the lost cluster.");
1000 NVolSetErrors(vol);
1001 }
1002 ntfs_free(rl2);
1003 break;
1004 }
1005 ni->runlist.rl = rl;
1006 status.runlist_merged = 1;
1007 ntfs_debug("Allocated cluster, lcn 0x%llx.",
1008 (unsigned long long)lcn);
1009 /* Map and lock the mft record and get the attribute record. */
1010 if (!NInoAttr(ni))
1011 base_ni = ni;
1012 else
1013 base_ni = ni->ext.base_ntfs_ino;
1014 m = map_mft_record(base_ni);
1015 if (IS_ERR(m)) {
1016 err = PTR_ERR(m);
1017 break;
1018 }
1019 ctx = ntfs_attr_get_search_ctx(base_ni, m);
1020 if (unlikely(!ctx)) {
1021 err = -ENOMEM;
1022 unmap_mft_record(base_ni);
1023 break;
1024 }
1025 status.mft_attr_mapped = 1;
1026 err = ntfs_attr_lookup(ni->type, ni->name, ni->name_len,
1027 CASE_SENSITIVE, bh_cpos, NULL, 0, ctx);
1028 if (unlikely(err)) {
1029 if (err == -ENOENT)
1030 err = -EIO;
1031 break;
1032 }
1033 m = ctx->mrec;
1034 a = ctx->attr;
1035 /*
1036 * Find the runlist element with which the attribute extent
1037 * starts. Note, we cannot use the _attr_ version because we
1038 * have mapped the mft record. That is ok because we know the
1039 * runlist fragment must be mapped already to have ever gotten
1040 * here, so we can just use the _rl_ version.
1041 */
1042 vcn = sle64_to_cpu(a->data.non_resident.lowest_vcn);
1043 rl2 = ntfs_rl_find_vcn_nolock(rl, vcn);
1044 BUG_ON(!rl2);
1045 BUG_ON(!rl2->length);
1046 BUG_ON(rl2->lcn < LCN_HOLE);
1047 highest_vcn = sle64_to_cpu(a->data.non_resident.highest_vcn);
1048 /*
1049 * If @highest_vcn is zero, calculate the real highest_vcn
1050 * (which can really be zero).
1051 */
1052 if (!highest_vcn)
1053 highest_vcn = (sle64_to_cpu(
1054 a->data.non_resident.allocated_size) >>
1055 vol->cluster_size_bits) - 1;
1056 /*
1057 * Determine the size of the mapping pairs array for the new
1058 * extent, i.e. the old extent with the hole filled.
1059 */
1060 mp_size = ntfs_get_size_for_mapping_pairs(vol, rl2, vcn,
1061 highest_vcn);
1062 if (unlikely(mp_size <= 0)) {
1063 if (!(err = mp_size))
1064 err = -EIO;
1065 ntfs_debug("Failed to get size for mapping pairs "
1066 "array, error code %i.", err);
1067 break;
1068 }
1069 /*
1070 * Resize the attribute record to fit the new mapping pairs
1071 * array.
1072 */
1073 attr_rec_len = le32_to_cpu(a->length);
1074 err = ntfs_attr_record_resize(m, a, mp_size + le16_to_cpu(
1075 a->data.non_resident.mapping_pairs_offset));
1076 if (unlikely(err)) {
1077 BUG_ON(err != -ENOSPC);
1078 // TODO: Deal with this by using the current attribute
1079 // and fill it with as much of the mapping pairs
1080 // array as possible. Then loop over each attribute
1081 // extent rewriting the mapping pairs arrays as we go
1082 // along and if when we reach the end we have not
1083 // enough space, try to resize the last attribute
1084 // extent and if even that fails, add a new attribute
1085 // extent.
1086 // We could also try to resize at each step in the hope
1087 // that we will not need to rewrite every single extent.
1088 // Note, we may need to decompress some extents to fill
1089 // the runlist as we are walking the extents...
1090 ntfs_error(vol->sb, "Not enough space in the mft "
1091 "record for the extended attribute "
1092 "record. This case is not "
1093 "implemented yet.");
1094 err = -EOPNOTSUPP;
1095 break ;
1096 }
1097 status.mp_rebuilt = 1;
1098 /*
1099 * Generate the mapping pairs array directly into the attribute
1100 * record.
1101 */
1102 err = ntfs_mapping_pairs_build(vol, (u8*)a + le16_to_cpu(
1103 a->data.non_resident.mapping_pairs_offset),
1104 mp_size, rl2, vcn, highest_vcn, NULL);
1105 if (unlikely(err)) {
1106 ntfs_error(vol->sb, "Cannot fill hole in inode 0x%lx, "
1107 "attribute type 0x%x, because building "
1108 "the mapping pairs failed with error "
1109 "code %i.", vi->i_ino,
1110 (unsigned)le32_to_cpu(ni->type), err);
1111 err = -EIO;
1112 break;
1113 }
1114 /* Update the highest_vcn but only if it was not set. */
1115 if (unlikely(!a->data.non_resident.highest_vcn))
1116 a->data.non_resident.highest_vcn =
1117 cpu_to_sle64(highest_vcn);
1118 /*
1119 * If the attribute is sparse/compressed, update the compressed
1120 * size in the ntfs_inode structure and the attribute record.
1121 */
1122 if (likely(NInoSparse(ni) || NInoCompressed(ni))) {
1123 /*
1124 * If we are not in the first attribute extent, switch
1125 * to it, but first ensure the changes will make it to
1126 * disk later.
1127 */
1128 if (a->data.non_resident.lowest_vcn) {
1129 flush_dcache_mft_record_page(ctx->ntfs_ino);
1130 mark_mft_record_dirty(ctx->ntfs_ino);
1131 ntfs_attr_reinit_search_ctx(ctx);
1132 err = ntfs_attr_lookup(ni->type, ni->name,
1133 ni->name_len, CASE_SENSITIVE,
1134 0, NULL, 0, ctx);
1135 if (unlikely(err)) {
1136 status.attr_switched = 1;
1137 break;
1138 }
1139 /* @m is not used any more so do not set it. */
1140 a = ctx->attr;
1141 }
1142 write_lock_irqsave(&ni->size_lock, flags);
1143 ni->itype.compressed.size += vol->cluster_size;
1144 a->data.non_resident.compressed_size =
1145 cpu_to_sle64(ni->itype.compressed.size);
1146 write_unlock_irqrestore(&ni->size_lock, flags);
1147 }
1148 /* Ensure the changes make it to disk. */
1149 flush_dcache_mft_record_page(ctx->ntfs_ino);
1150 mark_mft_record_dirty(ctx->ntfs_ino);
1151 ntfs_attr_put_search_ctx(ctx);
1152 unmap_mft_record(base_ni);
1153 /* Successfully filled the hole. */
1154 status.runlist_merged = 0;
1155 status.mft_attr_mapped = 0;
1156 status.mp_rebuilt = 0;
1157 /* Setup the map cache and use that to deal with the buffer. */
1158 was_hole = true;
1159 vcn = bh_cpos;
1160 vcn_len = 1;
1161 lcn_block = lcn << (vol->cluster_size_bits - blocksize_bits);
1162 cdelta = 0;
1163 /*
1164 * If the number of remaining clusters in the @pages is smaller
1165 * or equal to the number of cached clusters, unlock the
1166 * runlist as the map cache will be used from now on.
1167 */
1168 if (likely(vcn + vcn_len >= cend)) {
1169 up_write(&ni->runlist.lock);
1170 rl_write_locked = false;
1171 rl = NULL;
1172 }
1173 goto map_buffer_cached;
1174 } while (bh_pos += blocksize, (bh = bh->b_this_page) != head);
1175 /* If there are no errors, do the next page. */
1176 if (likely(!err && ++u < nr_pages))
1177 goto do_next_page;
1178 /* If there are no errors, release the runlist lock if we took it. */
1179 if (likely(!err)) {
1180 if (unlikely(rl_write_locked)) {
1181 up_write(&ni->runlist.lock);
1182 rl_write_locked = false;
1183 } else if (unlikely(rl))
1184 up_read(&ni->runlist.lock);
1185 rl = NULL;
1186 }
1187 /* If we issued read requests, let them complete. */
1188 read_lock_irqsave(&ni->size_lock, flags);
1189 initialized_size = ni->initialized_size;
1190 read_unlock_irqrestore(&ni->size_lock, flags);
1191 while (wait_bh > wait) {
1192 bh = *--wait_bh;
1193 wait_on_buffer(bh);
1194 if (likely(buffer_uptodate(bh))) {
1195 page = bh->b_page;
1196 bh_pos = ((s64)page->index << PAGE_SHIFT) +
1197 bh_offset(bh);
1198 /*
1199 * If the buffer overflows the initialized size, need
1200 * to zero the overflowing region.
1201 */
1202 if (unlikely(bh_pos + blocksize > initialized_size)) {
1203 int ofs = 0;
1204
1205 if (likely(bh_pos < initialized_size))
1206 ofs = initialized_size - bh_pos;
1207 zero_user_segment(page, bh_offset(bh) + ofs,
1208 blocksize);
1209 }
1210 } else /* if (unlikely(!buffer_uptodate(bh))) */
1211 err = -EIO;
1212 }
1213 if (likely(!err)) {
1214 /* Clear buffer_new on all buffers. */
1215 u = 0;
1216 do {
1217 bh = head = page_buffers(pages[u]);
1218 do {
1219 if (buffer_new(bh))
1220 clear_buffer_new(bh);
1221 } while ((bh = bh->b_this_page) != head);
1222 } while (++u < nr_pages);
1223 ntfs_debug("Done.");
1224 return err;
1225 }
1226 if (status.attr_switched) {
1227 /* Get back to the attribute extent we modified. */
1228 ntfs_attr_reinit_search_ctx(ctx);
1229 if (ntfs_attr_lookup(ni->type, ni->name, ni->name_len,
1230 CASE_SENSITIVE, bh_cpos, NULL, 0, ctx)) {
1231 ntfs_error(vol->sb, "Failed to find required "
1232 "attribute extent of attribute in "
1233 "error code path. Run chkdsk to "
1234 "recover.");
1235 write_lock_irqsave(&ni->size_lock, flags);
1236 ni->itype.compressed.size += vol->cluster_size;
1237 write_unlock_irqrestore(&ni->size_lock, flags);
1238 flush_dcache_mft_record_page(ctx->ntfs_ino);
1239 mark_mft_record_dirty(ctx->ntfs_ino);
1240 /*
1241 * The only thing that is now wrong is the compressed
1242 * size of the base attribute extent which chkdsk
1243 * should be able to fix.
1244 */
1245 NVolSetErrors(vol);
1246 } else {
1247 m = ctx->mrec;
1248 a = ctx->attr;
1249 status.attr_switched = 0;
1250 }
1251 }
1252 /*
1253 * If the runlist has been modified, need to restore it by punching a
1254 * hole into it and we then need to deallocate the on-disk cluster as
1255 * well. Note, we only modify the runlist if we are able to generate a
1256 * new mapping pairs array, i.e. only when the mapped attribute extent
1257 * is not switched.
1258 */
1259 if (status.runlist_merged && !status.attr_switched) {
1260 BUG_ON(!rl_write_locked);
1261 /* Make the file cluster we allocated sparse in the runlist. */
1262 if (ntfs_rl_punch_nolock(vol, &ni->runlist, bh_cpos, 1)) {
1263 ntfs_error(vol->sb, "Failed to punch hole into "
1264 "attribute runlist in error code "
1265 "path. Run chkdsk to recover the "
1266 "lost cluster.");
1267 NVolSetErrors(vol);
1268 } else /* if (success) */ {
1269 status.runlist_merged = 0;
1270 /*
1271 * Deallocate the on-disk cluster we allocated but only
1272 * if we succeeded in punching its vcn out of the
1273 * runlist.
1274 */
1275 down_write(&vol->lcnbmp_lock);
1276 if (ntfs_bitmap_clear_bit(vol->lcnbmp_ino, lcn)) {
1277 ntfs_error(vol->sb, "Failed to release "
1278 "allocated cluster in error "
1279 "code path. Run chkdsk to "
1280 "recover the lost cluster.");
1281 NVolSetErrors(vol);
1282 }
1283 up_write(&vol->lcnbmp_lock);
1284 }
1285 }
1286 /*
1287 * Resize the attribute record to its old size and rebuild the mapping
1288 * pairs array. Note, we only can do this if the runlist has been
1289 * restored to its old state which also implies that the mapped
1290 * attribute extent is not switched.
1291 */
1292 if (status.mp_rebuilt && !status.runlist_merged) {
1293 if (ntfs_attr_record_resize(m, a, attr_rec_len)) {
1294 ntfs_error(vol->sb, "Failed to restore attribute "
1295 "record in error code path. Run "
1296 "chkdsk to recover.");
1297 NVolSetErrors(vol);
1298 } else /* if (success) */ {
1299 if (ntfs_mapping_pairs_build(vol, (u8*)a +
1300 le16_to_cpu(a->data.non_resident.
1301 mapping_pairs_offset), attr_rec_len -
1302 le16_to_cpu(a->data.non_resident.
1303 mapping_pairs_offset), ni->runlist.rl,
1304 vcn, highest_vcn, NULL)) {
1305 ntfs_error(vol->sb, "Failed to restore "
1306 "mapping pairs array in error "
1307 "code path. Run chkdsk to "
1308 "recover.");
1309 NVolSetErrors(vol);
1310 }
1311 flush_dcache_mft_record_page(ctx->ntfs_ino);
1312 mark_mft_record_dirty(ctx->ntfs_ino);
1313 }
1314 }
1315 /* Release the mft record and the attribute. */
1316 if (status.mft_attr_mapped) {
1317 ntfs_attr_put_search_ctx(ctx);
1318 unmap_mft_record(base_ni);
1319 }
1320 /* Release the runlist lock. */
1321 if (rl_write_locked)
1322 up_write(&ni->runlist.lock);
1323 else if (rl)
1324 up_read(&ni->runlist.lock);
1325 /*
1326 * Zero out any newly allocated blocks to avoid exposing stale data.
1327 * If BH_New is set, we know that the block was newly allocated above
1328 * and that it has not been fully zeroed and marked dirty yet.
1329 */
1330 nr_pages = u;
1331 u = 0;
1332 end = bh_cpos << vol->cluster_size_bits;
1333 do {
1334 page = pages[u];
1335 bh = head = page_buffers(page);
1336 do {
1337 if (u == nr_pages &&
1338 ((s64)page->index << PAGE_SHIFT) +
1339 bh_offset(bh) >= end)
1340 break;
1341 if (!buffer_new(bh))
1342 continue;
1343 clear_buffer_new(bh);
1344 if (!buffer_uptodate(bh)) {
1345 if (PageUptodate(page))
1346 set_buffer_uptodate(bh);
1347 else {
1348 zero_user(page, bh_offset(bh),
1349 blocksize);
1350 set_buffer_uptodate(bh);
1351 }
1352 }
1353 mark_buffer_dirty(bh);
1354 } while ((bh = bh->b_this_page) != head);
1355 } while (++u <= nr_pages);
1356 ntfs_error(vol->sb, "Failed. Returning error code %i.", err);
1357 return err;
1358}
1359
1360static inline void ntfs_flush_dcache_pages(struct page **pages,
1361 unsigned nr_pages)
1362{
1363 BUG_ON(!nr_pages);
1364 /*
1365 * Warning: Do not do the decrement at the same time as the call to
1366 * flush_dcache_page() because it is a NULL macro on i386 and hence the
1367 * decrement never happens so the loop never terminates.
1368 */
1369 do {
1370 --nr_pages;
1371 flush_dcache_page(pages[nr_pages]);
1372 } while (nr_pages > 0);
1373}
1374
1375/**
1376 * ntfs_commit_pages_after_non_resident_write - commit the received data
1377 * @pages: array of destination pages
1378 * @nr_pages: number of pages in @pages
1379 * @pos: byte position in file at which the write begins
1380 * @bytes: number of bytes to be written
1381 *
1382 * See description of ntfs_commit_pages_after_write(), below.
1383 */
1384static inline int ntfs_commit_pages_after_non_resident_write(
1385 struct page **pages, const unsigned nr_pages,
1386 s64 pos, size_t bytes)
1387{
1388 s64 end, initialized_size;
1389 struct inode *vi;
1390 ntfs_inode *ni, *base_ni;
1391 struct buffer_head *bh, *head;
1392 ntfs_attr_search_ctx *ctx;
1393 MFT_RECORD *m;
1394 ATTR_RECORD *a;
1395 unsigned long flags;
1396 unsigned blocksize, u;
1397 int err;
1398
1399 vi = pages[0]->mapping->host;
1400 ni = NTFS_I(vi);
1401 blocksize = vi->i_sb->s_blocksize;
1402 end = pos + bytes;
1403 u = 0;
1404 do {
1405 s64 bh_pos;
1406 struct page *page;
1407 bool partial;
1408
1409 page = pages[u];
1410 bh_pos = (s64)page->index << PAGE_SHIFT;
1411 bh = head = page_buffers(page);
1412 partial = false;
1413 do {
1414 s64 bh_end;
1415
1416 bh_end = bh_pos + blocksize;
1417 if (bh_end <= pos || bh_pos >= end) {
1418 if (!buffer_uptodate(bh))
1419 partial = true;
1420 } else {
1421 set_buffer_uptodate(bh);
1422 mark_buffer_dirty(bh);
1423 }
1424 } while (bh_pos += blocksize, (bh = bh->b_this_page) != head);
1425 /*
1426 * If all buffers are now uptodate but the page is not, set the
1427 * page uptodate.
1428 */
1429 if (!partial && !PageUptodate(page))
1430 SetPageUptodate(page);
1431 } while (++u < nr_pages);
1432 /*
1433 * Finally, if we do not need to update initialized_size or i_size we
1434 * are finished.
1435 */
1436 read_lock_irqsave(&ni->size_lock, flags);
1437 initialized_size = ni->initialized_size;
1438 read_unlock_irqrestore(&ni->size_lock, flags);
1439 if (end <= initialized_size) {
1440 ntfs_debug("Done.");
1441 return 0;
1442 }
1443 /*
1444 * Update initialized_size/i_size as appropriate, both in the inode and
1445 * the mft record.
1446 */
1447 if (!NInoAttr(ni))
1448 base_ni = ni;
1449 else
1450 base_ni = ni->ext.base_ntfs_ino;
1451 /* Map, pin, and lock the mft record. */
1452 m = map_mft_record(base_ni);
1453 if (IS_ERR(m)) {
1454 err = PTR_ERR(m);
1455 m = NULL;
1456 ctx = NULL;
1457 goto err_out;
1458 }
1459 BUG_ON(!NInoNonResident(ni));
1460 ctx = ntfs_attr_get_search_ctx(base_ni, m);
1461 if (unlikely(!ctx)) {
1462 err = -ENOMEM;
1463 goto err_out;
1464 }
1465 err = ntfs_attr_lookup(ni->type, ni->name, ni->name_len,
1466 CASE_SENSITIVE, 0, NULL, 0, ctx);
1467 if (unlikely(err)) {
1468 if (err == -ENOENT)
1469 err = -EIO;
1470 goto err_out;
1471 }
1472 a = ctx->attr;
1473 BUG_ON(!a->non_resident);
1474 write_lock_irqsave(&ni->size_lock, flags);
1475 BUG_ON(end > ni->allocated_size);
1476 ni->initialized_size = end;
1477 a->data.non_resident.initialized_size = cpu_to_sle64(end);
1478 if (end > i_size_read(vi)) {
1479 i_size_write(vi, end);
1480 a->data.non_resident.data_size =
1481 a->data.non_resident.initialized_size;
1482 }
1483 write_unlock_irqrestore(&ni->size_lock, flags);
1484 /* Mark the mft record dirty, so it gets written back. */
1485 flush_dcache_mft_record_page(ctx->ntfs_ino);
1486 mark_mft_record_dirty(ctx->ntfs_ino);
1487 ntfs_attr_put_search_ctx(ctx);
1488 unmap_mft_record(base_ni);
1489 ntfs_debug("Done.");
1490 return 0;
1491err_out:
1492 if (ctx)
1493 ntfs_attr_put_search_ctx(ctx);
1494 if (m)
1495 unmap_mft_record(base_ni);
1496 ntfs_error(vi->i_sb, "Failed to update initialized_size/i_size (error "
1497 "code %i).", err);
1498 if (err != -ENOMEM)
1499 NVolSetErrors(ni->vol);
1500 return err;
1501}
1502
1503/**
1504 * ntfs_commit_pages_after_write - commit the received data
1505 * @pages: array of destination pages
1506 * @nr_pages: number of pages in @pages
1507 * @pos: byte position in file at which the write begins
1508 * @bytes: number of bytes to be written
1509 *
1510 * This is called from ntfs_file_buffered_write() with i_mutex held on the inode
1511 * (@pages[0]->mapping->host). There are @nr_pages pages in @pages which are
1512 * locked but not kmap()ped. The source data has already been copied into the
1513 * @page. ntfs_prepare_pages_for_non_resident_write() has been called before
1514 * the data was copied (for non-resident attributes only) and it returned
1515 * success.
1516 *
1517 * Need to set uptodate and mark dirty all buffers within the boundary of the
1518 * write. If all buffers in a page are uptodate we set the page uptodate, too.
1519 *
1520 * Setting the buffers dirty ensures that they get written out later when
1521 * ntfs_writepage() is invoked by the VM.
1522 *
1523 * Finally, we need to update i_size and initialized_size as appropriate both
1524 * in the inode and the mft record.
1525 *
1526 * This is modelled after fs/buffer.c::generic_commit_write(), which marks
1527 * buffers uptodate and dirty, sets the page uptodate if all buffers in the
1528 * page are uptodate, and updates i_size if the end of io is beyond i_size. In
1529 * that case, it also marks the inode dirty.
1530 *
1531 * If things have gone as outlined in
1532 * ntfs_prepare_pages_for_non_resident_write(), we do not need to do any page
1533 * content modifications here for non-resident attributes. For resident
1534 * attributes we need to do the uptodate bringing here which we combine with
1535 * the copying into the mft record which means we save one atomic kmap.
1536 *
1537 * Return 0 on success or -errno on error.
1538 */
1539static int ntfs_commit_pages_after_write(struct page **pages,
1540 const unsigned nr_pages, s64 pos, size_t bytes)
1541{
1542 s64 end, initialized_size;
1543 loff_t i_size;
1544 struct inode *vi;
1545 ntfs_inode *ni, *base_ni;
1546 struct page *page;
1547 ntfs_attr_search_ctx *ctx;
1548 MFT_RECORD *m;
1549 ATTR_RECORD *a;
1550 char *kattr, *kaddr;
1551 unsigned long flags;
1552 u32 attr_len;
1553 int err;
1554
1555 BUG_ON(!nr_pages);
1556 BUG_ON(!pages);
1557 page = pages[0];
1558 BUG_ON(!page);
1559 vi = page->mapping->host;
1560 ni = NTFS_I(vi);
1561 ntfs_debug("Entering for inode 0x%lx, attribute type 0x%x, start page "
1562 "index 0x%lx, nr_pages 0x%x, pos 0x%llx, bytes 0x%zx.",
1563 vi->i_ino, ni->type, page->index, nr_pages,
1564 (long long)pos, bytes);
1565 if (NInoNonResident(ni))
1566 return ntfs_commit_pages_after_non_resident_write(pages,
1567 nr_pages, pos, bytes);
1568 BUG_ON(nr_pages > 1);
1569 /*
1570 * Attribute is resident, implying it is not compressed, encrypted, or
1571 * sparse.
1572 */
1573 if (!NInoAttr(ni))
1574 base_ni = ni;
1575 else
1576 base_ni = ni->ext.base_ntfs_ino;
1577 BUG_ON(NInoNonResident(ni));
1578 /* Map, pin, and lock the mft record. */
1579 m = map_mft_record(base_ni);
1580 if (IS_ERR(m)) {
1581 err = PTR_ERR(m);
1582 m = NULL;
1583 ctx = NULL;
1584 goto err_out;
1585 }
1586 ctx = ntfs_attr_get_search_ctx(base_ni, m);
1587 if (unlikely(!ctx)) {
1588 err = -ENOMEM;
1589 goto err_out;
1590 }
1591 err = ntfs_attr_lookup(ni->type, ni->name, ni->name_len,
1592 CASE_SENSITIVE, 0, NULL, 0, ctx);
1593 if (unlikely(err)) {
1594 if (err == -ENOENT)
1595 err = -EIO;
1596 goto err_out;
1597 }
1598 a = ctx->attr;
1599 BUG_ON(a->non_resident);
1600 /* The total length of the attribute value. */
1601 attr_len = le32_to_cpu(a->data.resident.value_length);
1602 i_size = i_size_read(vi);
1603 BUG_ON(attr_len != i_size);
1604 BUG_ON(pos > attr_len);
1605 end = pos + bytes;
1606 BUG_ON(end > le32_to_cpu(a->length) -
1607 le16_to_cpu(a->data.resident.value_offset));
1608 kattr = (u8*)a + le16_to_cpu(a->data.resident.value_offset);
1609 kaddr = kmap_atomic(page);
1610 /* Copy the received data from the page to the mft record. */
1611 memcpy(kattr + pos, kaddr + pos, bytes);
1612 /* Update the attribute length if necessary. */
1613 if (end > attr_len) {
1614 attr_len = end;
1615 a->data.resident.value_length = cpu_to_le32(attr_len);
1616 }
1617 /*
1618 * If the page is not uptodate, bring the out of bounds area(s)
1619 * uptodate by copying data from the mft record to the page.
1620 */
1621 if (!PageUptodate(page)) {
1622 if (pos > 0)
1623 memcpy(kaddr, kattr, pos);
1624 if (end < attr_len)
1625 memcpy(kaddr + end, kattr + end, attr_len - end);
1626 /* Zero the region outside the end of the attribute value. */
1627 memset(kaddr + attr_len, 0, PAGE_SIZE - attr_len);
1628 flush_dcache_page(page);
1629 SetPageUptodate(page);
1630 }
1631 kunmap_atomic(kaddr);
1632 /* Update initialized_size/i_size if necessary. */
1633 read_lock_irqsave(&ni->size_lock, flags);
1634 initialized_size = ni->initialized_size;
1635 BUG_ON(end > ni->allocated_size);
1636 read_unlock_irqrestore(&ni->size_lock, flags);
1637 BUG_ON(initialized_size != i_size);
1638 if (end > initialized_size) {
1639 write_lock_irqsave(&ni->size_lock, flags);
1640 ni->initialized_size = end;
1641 i_size_write(vi, end);
1642 write_unlock_irqrestore(&ni->size_lock, flags);
1643 }
1644 /* Mark the mft record dirty, so it gets written back. */
1645 flush_dcache_mft_record_page(ctx->ntfs_ino);
1646 mark_mft_record_dirty(ctx->ntfs_ino);
1647 ntfs_attr_put_search_ctx(ctx);
1648 unmap_mft_record(base_ni);
1649 ntfs_debug("Done.");
1650 return 0;
1651err_out:
1652 if (err == -ENOMEM) {
1653 ntfs_warning(vi->i_sb, "Error allocating memory required to "
1654 "commit the write.");
1655 if (PageUptodate(page)) {
1656 ntfs_warning(vi->i_sb, "Page is uptodate, setting "
1657 "dirty so the write will be retried "
1658 "later on by the VM.");
1659 /*
1660 * Put the page on mapping->dirty_pages, but leave its
1661 * buffers' dirty state as-is.
1662 */
1663 __set_page_dirty_nobuffers(page);
1664 err = 0;
1665 } else
1666 ntfs_error(vi->i_sb, "Page is not uptodate. Written "
1667 "data has been lost.");
1668 } else {
1669 ntfs_error(vi->i_sb, "Resident attribute commit write failed "
1670 "with error %i.", err);
1671 NVolSetErrors(ni->vol);
1672 }
1673 if (ctx)
1674 ntfs_attr_put_search_ctx(ctx);
1675 if (m)
1676 unmap_mft_record(base_ni);
1677 return err;
1678}
1679
1680/*
1681 * Copy as much as we can into the pages and return the number of bytes which
1682 * were successfully copied. If a fault is encountered then clear the pages
1683 * out to (ofs + bytes) and return the number of bytes which were copied.
1684 */
1685static size_t ntfs_copy_from_user_iter(struct page **pages, unsigned nr_pages,
1686 unsigned ofs, struct iov_iter *i, size_t bytes)
1687{
1688 struct page **last_page = pages + nr_pages;
1689 size_t total = 0;
1690 struct iov_iter data = *i;
1691 unsigned len, copied;
1692
1693 do {
1694 len = PAGE_SIZE - ofs;
1695 if (len > bytes)
1696 len = bytes;
1697 copied = iov_iter_copy_from_user_atomic(*pages, &data, ofs,
1698 len);
1699 total += copied;
1700 bytes -= copied;
1701 if (!bytes)
1702 break;
1703 iov_iter_advance(&data, copied);
1704 if (copied < len)
1705 goto err;
1706 ofs = 0;
1707 } while (++pages < last_page);
1708out:
1709 return total;
1710err:
1711 /* Zero the rest of the target like __copy_from_user(). */
1712 len = PAGE_SIZE - copied;
1713 do {
1714 if (len > bytes)
1715 len = bytes;
1716 zero_user(*pages, copied, len);
1717 bytes -= len;
1718 copied = 0;
1719 len = PAGE_SIZE;
1720 } while (++pages < last_page);
1721 goto out;
1722}
1723
1724/**
1725 * ntfs_perform_write - perform buffered write to a file
1726 * @file: file to write to
1727 * @i: iov_iter with data to write
1728 * @pos: byte offset in file at which to begin writing to
1729 */
1730static ssize_t ntfs_perform_write(struct file *file, struct iov_iter *i,
1731 loff_t pos)
1732{
1733 struct address_space *mapping = file->f_mapping;
1734 struct inode *vi = mapping->host;
1735 ntfs_inode *ni = NTFS_I(vi);
1736 ntfs_volume *vol = ni->vol;
1737 struct page *pages[NTFS_MAX_PAGES_PER_CLUSTER];
1738 struct page *cached_page = NULL;
1739 VCN last_vcn;
1740 LCN lcn;
1741 size_t bytes;
1742 ssize_t status, written = 0;
1743 unsigned nr_pages;
1744
1745 ntfs_debug("Entering for i_ino 0x%lx, attribute type 0x%x, pos "
1746 "0x%llx, count 0x%lx.", vi->i_ino,
1747 (unsigned)le32_to_cpu(ni->type),
1748 (unsigned long long)pos,
1749 (unsigned long)iov_iter_count(i));
1750 /*
1751 * If a previous ntfs_truncate() failed, repeat it and abort if it
1752 * fails again.
1753 */
1754 if (unlikely(NInoTruncateFailed(ni))) {
1755 int err;
1756
1757 inode_dio_wait(vi);
1758 err = ntfs_truncate(vi);
1759 if (err || NInoTruncateFailed(ni)) {
1760 if (!err)
1761 err = -EIO;
1762 ntfs_error(vol->sb, "Cannot perform write to inode "
1763 "0x%lx, attribute type 0x%x, because "
1764 "ntfs_truncate() failed (error code "
1765 "%i).", vi->i_ino,
1766 (unsigned)le32_to_cpu(ni->type), err);
1767 return err;
1768 }
1769 }
1770 /*
1771 * Determine the number of pages per cluster for non-resident
1772 * attributes.
1773 */
1774 nr_pages = 1;
1775 if (vol->cluster_size > PAGE_SIZE && NInoNonResident(ni))
1776 nr_pages = vol->cluster_size >> PAGE_SHIFT;
1777 last_vcn = -1;
1778 do {
1779 VCN vcn;
1780 pgoff_t idx, start_idx;
1781 unsigned ofs, do_pages, u;
1782 size_t copied;
1783
1784 start_idx = idx = pos >> PAGE_SHIFT;
1785 ofs = pos & ~PAGE_MASK;
1786 bytes = PAGE_SIZE - ofs;
1787 do_pages = 1;
1788 if (nr_pages > 1) {
1789 vcn = pos >> vol->cluster_size_bits;
1790 if (vcn != last_vcn) {
1791 last_vcn = vcn;
1792 /*
1793 * Get the lcn of the vcn the write is in. If
1794 * it is a hole, need to lock down all pages in
1795 * the cluster.
1796 */
1797 down_read(&ni->runlist.lock);
1798 lcn = ntfs_attr_vcn_to_lcn_nolock(ni, pos >>
1799 vol->cluster_size_bits, false);
1800 up_read(&ni->runlist.lock);
1801 if (unlikely(lcn < LCN_HOLE)) {
1802 if (lcn == LCN_ENOMEM)
1803 status = -ENOMEM;
1804 else {
1805 status = -EIO;
1806 ntfs_error(vol->sb, "Cannot "
1807 "perform write to "
1808 "inode 0x%lx, "
1809 "attribute type 0x%x, "
1810 "because the attribute "
1811 "is corrupt.",
1812 vi->i_ino, (unsigned)
1813 le32_to_cpu(ni->type));
1814 }
1815 break;
1816 }
1817 if (lcn == LCN_HOLE) {
1818 start_idx = (pos & ~(s64)
1819 vol->cluster_size_mask)
1820 >> PAGE_SHIFT;
1821 bytes = vol->cluster_size - (pos &
1822 vol->cluster_size_mask);
1823 do_pages = nr_pages;
1824 }
1825 }
1826 }
1827 if (bytes > iov_iter_count(i))
1828 bytes = iov_iter_count(i);
1829again:
1830 /*
1831 * Bring in the user page(s) that we will copy from _first_.
1832 * Otherwise there is a nasty deadlock on copying from the same
1833 * page(s) as we are writing to, without it/them being marked
1834 * up-to-date. Note, at present there is nothing to stop the
1835 * pages being swapped out between us bringing them into memory
1836 * and doing the actual copying.
1837 */
1838 if (unlikely(iov_iter_fault_in_readable(i, bytes))) {
1839 status = -EFAULT;
1840 break;
1841 }
1842 /* Get and lock @do_pages starting at index @start_idx. */
1843 status = __ntfs_grab_cache_pages(mapping, start_idx, do_pages,
1844 pages, &cached_page);
1845 if (unlikely(status))
1846 break;
1847 /*
1848 * For non-resident attributes, we need to fill any holes with
1849 * actual clusters and ensure all bufferes are mapped. We also
1850 * need to bring uptodate any buffers that are only partially
1851 * being written to.
1852 */
1853 if (NInoNonResident(ni)) {
1854 status = ntfs_prepare_pages_for_non_resident_write(
1855 pages, do_pages, pos, bytes);
1856 if (unlikely(status)) {
1857 do {
1858 unlock_page(pages[--do_pages]);
1859 put_page(pages[do_pages]);
1860 } while (do_pages);
1861 break;
1862 }
1863 }
1864 u = (pos >> PAGE_SHIFT) - pages[0]->index;
1865 copied = ntfs_copy_from_user_iter(pages + u, do_pages - u, ofs,
1866 i, bytes);
1867 ntfs_flush_dcache_pages(pages + u, do_pages - u);
1868 status = 0;
1869 if (likely(copied == bytes)) {
1870 status = ntfs_commit_pages_after_write(pages, do_pages,
1871 pos, bytes);
1872 if (!status)
1873 status = bytes;
1874 }
1875 do {
1876 unlock_page(pages[--do_pages]);
1877 put_page(pages[do_pages]);
1878 } while (do_pages);
1879 if (unlikely(status < 0))
1880 break;
1881 copied = status;
1882 cond_resched();
1883 if (unlikely(!copied)) {
1884 size_t sc;
1885
1886 /*
1887 * We failed to copy anything. Fall back to single
1888 * segment length write.
1889 *
1890 * This is needed to avoid possible livelock in the
1891 * case that all segments in the iov cannot be copied
1892 * at once without a pagefault.
1893 */
1894 sc = iov_iter_single_seg_count(i);
1895 if (bytes > sc)
1896 bytes = sc;
1897 goto again;
1898 }
1899 iov_iter_advance(i, copied);
1900 pos += copied;
1901 written += copied;
1902 balance_dirty_pages_ratelimited(mapping);
1903 if (fatal_signal_pending(current)) {
1904 status = -EINTR;
1905 break;
1906 }
1907 } while (iov_iter_count(i));
1908 if (cached_page)
1909 put_page(cached_page);
1910 ntfs_debug("Done. Returning %s (written 0x%lx, status %li).",
1911 written ? "written" : "status", (unsigned long)written,
1912 (long)status);
1913 return written ? written : status;
1914}
1915
1916/**
1917 * ntfs_file_write_iter - simple wrapper for ntfs_file_write_iter_nolock()
1918 * @iocb: IO state structure
1919 * @from: iov_iter with data to write
1920 *
1921 * Basically the same as generic_file_write_iter() except that it ends up
1922 * up calling ntfs_perform_write() instead of generic_perform_write() and that
1923 * O_DIRECT is not implemented.
1924 */
1925static ssize_t ntfs_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
1926{
1927 struct file *file = iocb->ki_filp;
1928 struct inode *vi = file_inode(file);
1929 ssize_t written = 0;
1930 ssize_t err;
1931
1932 inode_lock(vi);
1933 /* We can write back this queue in page reclaim. */
1934 current->backing_dev_info = inode_to_bdi(vi);
1935 err = ntfs_prepare_file_for_write(iocb, from);
1936 if (iov_iter_count(from) && !err)
1937 written = ntfs_perform_write(file, from, iocb->ki_pos);
1938 current->backing_dev_info = NULL;
1939 inode_unlock(vi);
1940 iocb->ki_pos += written;
1941 if (likely(written > 0))
1942 written = generic_write_sync(iocb, written);
1943 return written ? written : err;
1944}
1945
1946/**
1947 * ntfs_file_fsync - sync a file to disk
1948 * @filp: file to be synced
1949 * @datasync: if non-zero only flush user data and not metadata
1950 *
1951 * Data integrity sync of a file to disk. Used for fsync, fdatasync, and msync
1952 * system calls. This function is inspired by fs/buffer.c::file_fsync().
1953 *
1954 * If @datasync is false, write the mft record and all associated extent mft
1955 * records as well as the $DATA attribute and then sync the block device.
1956 *
1957 * If @datasync is true and the attribute is non-resident, we skip the writing
1958 * of the mft record and all associated extent mft records (this might still
1959 * happen due to the write_inode_now() call).
1960 *
1961 * Also, if @datasync is true, we do not wait on the inode to be written out
1962 * but we always wait on the page cache pages to be written out.
1963 *
1964 * Locking: Caller must hold i_mutex on the inode.
1965 *
1966 * TODO: We should probably also write all attribute/index inodes associated
1967 * with this inode but since we have no simple way of getting to them we ignore
1968 * this problem for now.
1969 */
1970static int ntfs_file_fsync(struct file *filp, loff_t start, loff_t end,
1971 int datasync)
1972{
1973 struct inode *vi = filp->f_mapping->host;
1974 int err, ret = 0;
1975
1976 ntfs_debug("Entering for inode 0x%lx.", vi->i_ino);
1977
1978 err = file_write_and_wait_range(filp, start, end);
1979 if (err)
1980 return err;
1981 inode_lock(vi);
1982
1983 BUG_ON(S_ISDIR(vi->i_mode));
1984 if (!datasync || !NInoNonResident(NTFS_I(vi)))
1985 ret = __ntfs_write_inode(vi, 1);
1986 write_inode_now(vi, !datasync);
1987 /*
1988 * NOTE: If we were to use mapping->private_list (see ext2 and
1989 * fs/buffer.c) for dirty blocks then we could optimize the below to be
1990 * sync_mapping_buffers(vi->i_mapping).
1991 */
1992 err = sync_blockdev(vi->i_sb->s_bdev);
1993 if (unlikely(err && !ret))
1994 ret = err;
1995 if (likely(!ret))
1996 ntfs_debug("Done.");
1997 else
1998 ntfs_warning(vi->i_sb, "Failed to f%ssync inode 0x%lx. Error "
1999 "%u.", datasync ? "data" : "", vi->i_ino, -ret);
2000 inode_unlock(vi);
2001 return ret;
2002}
2003
2004#endif /* NTFS_RW */
2005
2006const struct file_operations ntfs_file_ops = {
2007 .llseek = generic_file_llseek,
2008 .read_iter = generic_file_read_iter,
2009#ifdef NTFS_RW
2010 .write_iter = ntfs_file_write_iter,
2011 .fsync = ntfs_file_fsync,
2012#endif /* NTFS_RW */
2013 .mmap = generic_file_mmap,
2014 .open = ntfs_file_open,
2015 .splice_read = generic_file_splice_read,
2016};
2017
2018const struct inode_operations ntfs_file_inode_ops = {
2019#ifdef NTFS_RW
2020 .setattr = ntfs_setattr,
2021#endif /* NTFS_RW */
2022};
2023
2024const struct file_operations ntfs_empty_file_ops = {};
2025
2026const struct inode_operations ntfs_empty_inode_ops = {};