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1 /*
2  * file.c - NTFS kernel file operations.  Part of the Linux-NTFS project.
3  *
4  * Copyright (c) 2001-2011 Anton Altaparmakov and Tuxera Inc.
5  *
6  * This program/include file is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU General Public License as published
8  * by the Free Software Foundation; either version 2 of the License, or
9  * (at your option) any later version.
10  *
11  * This program/include file is distributed in the hope that it will be
12  * useful, but WITHOUT ANY WARRANTY; without even the implied warranty
13  * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14  * GNU General Public License for more details.
15  *
16  * You should have received a copy of the GNU General Public License
17  * along with this program (in the main directory of the Linux-NTFS
18  * distribution in the file COPYING); if not, write to the Free Software
19  * Foundation,Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
20  */
21 
22 #include <linux/buffer_head.h>
23 #include <linux/gfp.h>
24 #include <linux/pagemap.h>
25 #include <linux/pagevec.h>
26 #include <linux/sched.h>
27 #include <linux/swap.h>
28 #include <linux/uio.h>
29 #include <linux/writeback.h>
30 
31 #include <asm/page.h>
32 #include <asm/uaccess.h>
33 
34 #include "attrib.h"
35 #include "bitmap.h"
36 #include "inode.h"
37 #include "debug.h"
38 #include "lcnalloc.h"
39 #include "malloc.h"
40 #include "mft.h"
41 #include "ntfs.h"
42 
43 /**
44  * ntfs_file_open - called when an inode is about to be opened
45  * @vi:		inode to be opened
46  * @filp:	file structure describing the inode
47  *
48  * Limit file size to the page cache limit on architectures where unsigned long
49  * is 32-bits. This is the most we can do for now without overflowing the page
50  * cache page index. Doing it this way means we don't run into problems because
51  * of existing too large files. It would be better to allow the user to read
52  * the beginning of the file but I doubt very much anyone is going to hit this
53  * check on a 32-bit architecture, so there is no point in adding the extra
54  * complexity required to support this.
55  *
56  * On 64-bit architectures, the check is hopefully optimized away by the
57  * compiler.
58  *
59  * After the check passes, just call generic_file_open() to do its work.
60  */
ntfs_file_open(struct inode * vi,struct file * filp)61 static int ntfs_file_open(struct inode *vi, struct file *filp)
62 {
63 	if (sizeof(unsigned long) < 8) {
64 		if (i_size_read(vi) > MAX_LFS_FILESIZE)
65 			return -EOVERFLOW;
66 	}
67 	return generic_file_open(vi, filp);
68 }
69 
70 #ifdef NTFS_RW
71 
72 /**
73  * ntfs_attr_extend_initialized - extend the initialized size of an attribute
74  * @ni:			ntfs inode of the attribute to extend
75  * @new_init_size:	requested new initialized size in bytes
76  * @cached_page:	store any allocated but unused page here
77  * @lru_pvec:		lru-buffering pagevec of the caller
78  *
79  * Extend the initialized size of an attribute described by the ntfs inode @ni
80  * to @new_init_size bytes.  This involves zeroing any non-sparse space between
81  * the old initialized size and @new_init_size both in the page cache and on
82  * disk (if relevant complete pages are already uptodate in the page cache then
83  * these are simply marked dirty).
84  *
85  * As a side-effect, the file size (vfs inode->i_size) may be incremented as,
86  * in the resident attribute case, it is tied to the initialized size and, in
87  * the non-resident attribute case, it may not fall below the initialized size.
88  *
89  * Note that if the attribute is resident, we do not need to touch the page
90  * cache at all.  This is because if the page cache page is not uptodate we
91  * bring it uptodate later, when doing the write to the mft record since we
92  * then already have the page mapped.  And if the page is uptodate, the
93  * non-initialized region will already have been zeroed when the page was
94  * brought uptodate and the region may in fact already have been overwritten
95  * with new data via mmap() based writes, so we cannot just zero it.  And since
96  * POSIX specifies that the behaviour of resizing a file whilst it is mmap()ped
97  * is unspecified, we choose not to do zeroing and thus we do not need to touch
98  * the page at all.  For a more detailed explanation see ntfs_truncate() in
99  * fs/ntfs/inode.c.
100  *
101  * Return 0 on success and -errno on error.  In the case that an error is
102  * encountered it is possible that the initialized size will already have been
103  * incremented some way towards @new_init_size but it is guaranteed that if
104  * this is the case, the necessary zeroing will also have happened and that all
105  * metadata is self-consistent.
106  *
107  * Locking: i_mutex on the vfs inode corrseponsind to the ntfs inode @ni must be
108  *	    held by the caller.
109  */
ntfs_attr_extend_initialized(ntfs_inode * ni,const s64 new_init_size)110 static int ntfs_attr_extend_initialized(ntfs_inode *ni, const s64 new_init_size)
111 {
112 	s64 old_init_size;
113 	loff_t old_i_size;
114 	pgoff_t index, end_index;
115 	unsigned long flags;
116 	struct inode *vi = VFS_I(ni);
117 	ntfs_inode *base_ni;
118 	MFT_RECORD *m = NULL;
119 	ATTR_RECORD *a;
120 	ntfs_attr_search_ctx *ctx = NULL;
121 	struct address_space *mapping;
122 	struct page *page = NULL;
123 	u8 *kattr;
124 	int err;
125 	u32 attr_len;
126 
127 	read_lock_irqsave(&ni->size_lock, flags);
128 	old_init_size = ni->initialized_size;
129 	old_i_size = i_size_read(vi);
130 	BUG_ON(new_init_size > ni->allocated_size);
131 	read_unlock_irqrestore(&ni->size_lock, flags);
132 	ntfs_debug("Entering for i_ino 0x%lx, attribute type 0x%x, "
133 			"old_initialized_size 0x%llx, "
134 			"new_initialized_size 0x%llx, i_size 0x%llx.",
135 			vi->i_ino, (unsigned)le32_to_cpu(ni->type),
136 			(unsigned long long)old_init_size,
137 			(unsigned long long)new_init_size, old_i_size);
138 	if (!NInoAttr(ni))
139 		base_ni = ni;
140 	else
141 		base_ni = ni->ext.base_ntfs_ino;
142 	/* Use goto to reduce indentation and we need the label below anyway. */
143 	if (NInoNonResident(ni))
144 		goto do_non_resident_extend;
145 	BUG_ON(old_init_size != old_i_size);
146 	m = map_mft_record(base_ni);
147 	if (IS_ERR(m)) {
148 		err = PTR_ERR(m);
149 		m = NULL;
150 		goto err_out;
151 	}
152 	ctx = ntfs_attr_get_search_ctx(base_ni, m);
153 	if (unlikely(!ctx)) {
154 		err = -ENOMEM;
155 		goto err_out;
156 	}
157 	err = ntfs_attr_lookup(ni->type, ni->name, ni->name_len,
158 			CASE_SENSITIVE, 0, NULL, 0, ctx);
159 	if (unlikely(err)) {
160 		if (err == -ENOENT)
161 			err = -EIO;
162 		goto err_out;
163 	}
164 	m = ctx->mrec;
165 	a = ctx->attr;
166 	BUG_ON(a->non_resident);
167 	/* The total length of the attribute value. */
168 	attr_len = le32_to_cpu(a->data.resident.value_length);
169 	BUG_ON(old_i_size != (loff_t)attr_len);
170 	/*
171 	 * Do the zeroing in the mft record and update the attribute size in
172 	 * the mft record.
173 	 */
174 	kattr = (u8*)a + le16_to_cpu(a->data.resident.value_offset);
175 	memset(kattr + attr_len, 0, new_init_size - attr_len);
176 	a->data.resident.value_length = cpu_to_le32((u32)new_init_size);
177 	/* Finally, update the sizes in the vfs and ntfs inodes. */
178 	write_lock_irqsave(&ni->size_lock, flags);
179 	i_size_write(vi, new_init_size);
180 	ni->initialized_size = new_init_size;
181 	write_unlock_irqrestore(&ni->size_lock, flags);
182 	goto done;
183 do_non_resident_extend:
184 	/*
185 	 * If the new initialized size @new_init_size exceeds the current file
186 	 * size (vfs inode->i_size), we need to extend the file size to the
187 	 * new initialized size.
188 	 */
189 	if (new_init_size > old_i_size) {
190 		m = map_mft_record(base_ni);
191 		if (IS_ERR(m)) {
192 			err = PTR_ERR(m);
193 			m = NULL;
194 			goto err_out;
195 		}
196 		ctx = ntfs_attr_get_search_ctx(base_ni, m);
197 		if (unlikely(!ctx)) {
198 			err = -ENOMEM;
199 			goto err_out;
200 		}
201 		err = ntfs_attr_lookup(ni->type, ni->name, ni->name_len,
202 				CASE_SENSITIVE, 0, NULL, 0, ctx);
203 		if (unlikely(err)) {
204 			if (err == -ENOENT)
205 				err = -EIO;
206 			goto err_out;
207 		}
208 		m = ctx->mrec;
209 		a = ctx->attr;
210 		BUG_ON(!a->non_resident);
211 		BUG_ON(old_i_size != (loff_t)
212 				sle64_to_cpu(a->data.non_resident.data_size));
213 		a->data.non_resident.data_size = cpu_to_sle64(new_init_size);
214 		flush_dcache_mft_record_page(ctx->ntfs_ino);
215 		mark_mft_record_dirty(ctx->ntfs_ino);
216 		/* Update the file size in the vfs inode. */
217 		i_size_write(vi, new_init_size);
218 		ntfs_attr_put_search_ctx(ctx);
219 		ctx = NULL;
220 		unmap_mft_record(base_ni);
221 		m = NULL;
222 	}
223 	mapping = vi->i_mapping;
224 	index = old_init_size >> PAGE_CACHE_SHIFT;
225 	end_index = (new_init_size + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
226 	do {
227 		/*
228 		 * Read the page.  If the page is not present, this will zero
229 		 * the uninitialized regions for us.
230 		 */
231 		page = read_mapping_page(mapping, index, NULL);
232 		if (IS_ERR(page)) {
233 			err = PTR_ERR(page);
234 			goto init_err_out;
235 		}
236 		if (unlikely(PageError(page))) {
237 			page_cache_release(page);
238 			err = -EIO;
239 			goto init_err_out;
240 		}
241 		/*
242 		 * Update the initialized size in the ntfs inode.  This is
243 		 * enough to make ntfs_writepage() work.
244 		 */
245 		write_lock_irqsave(&ni->size_lock, flags);
246 		ni->initialized_size = (s64)(index + 1) << PAGE_CACHE_SHIFT;
247 		if (ni->initialized_size > new_init_size)
248 			ni->initialized_size = new_init_size;
249 		write_unlock_irqrestore(&ni->size_lock, flags);
250 		/* Set the page dirty so it gets written out. */
251 		set_page_dirty(page);
252 		page_cache_release(page);
253 		/*
254 		 * Play nice with the vm and the rest of the system.  This is
255 		 * very much needed as we can potentially be modifying the
256 		 * initialised size from a very small value to a really huge
257 		 * value, e.g.
258 		 *	f = open(somefile, O_TRUNC);
259 		 *	truncate(f, 10GiB);
260 		 *	seek(f, 10GiB);
261 		 *	write(f, 1);
262 		 * And this would mean we would be marking dirty hundreds of
263 		 * thousands of pages or as in the above example more than
264 		 * two and a half million pages!
265 		 *
266 		 * TODO: For sparse pages could optimize this workload by using
267 		 * the FsMisc / MiscFs page bit as a "PageIsSparse" bit.  This
268 		 * would be set in readpage for sparse pages and here we would
269 		 * not need to mark dirty any pages which have this bit set.
270 		 * The only caveat is that we have to clear the bit everywhere
271 		 * where we allocate any clusters that lie in the page or that
272 		 * contain the page.
273 		 *
274 		 * TODO: An even greater optimization would be for us to only
275 		 * call readpage() on pages which are not in sparse regions as
276 		 * determined from the runlist.  This would greatly reduce the
277 		 * number of pages we read and make dirty in the case of sparse
278 		 * files.
279 		 */
280 		balance_dirty_pages_ratelimited(mapping);
281 		cond_resched();
282 	} while (++index < end_index);
283 	read_lock_irqsave(&ni->size_lock, flags);
284 	BUG_ON(ni->initialized_size != new_init_size);
285 	read_unlock_irqrestore(&ni->size_lock, flags);
286 	/* Now bring in sync the initialized_size in the mft record. */
287 	m = map_mft_record(base_ni);
288 	if (IS_ERR(m)) {
289 		err = PTR_ERR(m);
290 		m = NULL;
291 		goto init_err_out;
292 	}
293 	ctx = ntfs_attr_get_search_ctx(base_ni, m);
294 	if (unlikely(!ctx)) {
295 		err = -ENOMEM;
296 		goto init_err_out;
297 	}
298 	err = ntfs_attr_lookup(ni->type, ni->name, ni->name_len,
299 			CASE_SENSITIVE, 0, NULL, 0, ctx);
300 	if (unlikely(err)) {
301 		if (err == -ENOENT)
302 			err = -EIO;
303 		goto init_err_out;
304 	}
305 	m = ctx->mrec;
306 	a = ctx->attr;
307 	BUG_ON(!a->non_resident);
308 	a->data.non_resident.initialized_size = cpu_to_sle64(new_init_size);
309 done:
310 	flush_dcache_mft_record_page(ctx->ntfs_ino);
311 	mark_mft_record_dirty(ctx->ntfs_ino);
312 	if (ctx)
313 		ntfs_attr_put_search_ctx(ctx);
314 	if (m)
315 		unmap_mft_record(base_ni);
316 	ntfs_debug("Done, initialized_size 0x%llx, i_size 0x%llx.",
317 			(unsigned long long)new_init_size, i_size_read(vi));
318 	return 0;
319 init_err_out:
320 	write_lock_irqsave(&ni->size_lock, flags);
321 	ni->initialized_size = old_init_size;
322 	write_unlock_irqrestore(&ni->size_lock, flags);
323 err_out:
324 	if (ctx)
325 		ntfs_attr_put_search_ctx(ctx);
326 	if (m)
327 		unmap_mft_record(base_ni);
328 	ntfs_debug("Failed.  Returning error code %i.", err);
329 	return err;
330 }
331 
332 /**
333  * ntfs_fault_in_pages_readable -
334  *
335  * Fault a number of userspace pages into pagetables.
336  *
337  * Unlike include/linux/pagemap.h::fault_in_pages_readable(), this one copes
338  * with more than two userspace pages as well as handling the single page case
339  * elegantly.
340  *
341  * If you find this difficult to understand, then think of the while loop being
342  * the following code, except that we do without the integer variable ret:
343  *
344  *	do {
345  *		ret = __get_user(c, uaddr);
346  *		uaddr += PAGE_SIZE;
347  *	} while (!ret && uaddr < end);
348  *
349  * Note, the final __get_user() may well run out-of-bounds of the user buffer,
350  * but _not_ out-of-bounds of the page the user buffer belongs to, and since
351  * this is only a read and not a write, and since it is still in the same page,
352  * it should not matter and this makes the code much simpler.
353  */
ntfs_fault_in_pages_readable(const char __user * uaddr,int bytes)354 static inline void ntfs_fault_in_pages_readable(const char __user *uaddr,
355 		int bytes)
356 {
357 	const char __user *end;
358 	volatile char c;
359 
360 	/* Set @end to the first byte outside the last page we care about. */
361 	end = (const char __user*)PAGE_ALIGN((unsigned long)uaddr + bytes);
362 
363 	while (!__get_user(c, uaddr) && (uaddr += PAGE_SIZE, uaddr < end))
364 		;
365 }
366 
367 /**
368  * ntfs_fault_in_pages_readable_iovec -
369  *
370  * Same as ntfs_fault_in_pages_readable() but operates on an array of iovecs.
371  */
ntfs_fault_in_pages_readable_iovec(const struct iovec * iov,size_t iov_ofs,int bytes)372 static inline void ntfs_fault_in_pages_readable_iovec(const struct iovec *iov,
373 		size_t iov_ofs, int bytes)
374 {
375 	do {
376 		const char __user *buf;
377 		unsigned len;
378 
379 		buf = iov->iov_base + iov_ofs;
380 		len = iov->iov_len - iov_ofs;
381 		if (len > bytes)
382 			len = bytes;
383 		ntfs_fault_in_pages_readable(buf, len);
384 		bytes -= len;
385 		iov++;
386 		iov_ofs = 0;
387 	} while (bytes);
388 }
389 
390 /**
391  * __ntfs_grab_cache_pages - obtain a number of locked pages
392  * @mapping:	address space mapping from which to obtain page cache pages
393  * @index:	starting index in @mapping at which to begin obtaining pages
394  * @nr_pages:	number of page cache pages to obtain
395  * @pages:	array of pages in which to return the obtained page cache pages
396  * @cached_page: allocated but as yet unused page
397  * @lru_pvec:	lru-buffering pagevec of caller
398  *
399  * Obtain @nr_pages locked page cache pages from the mapping @mapping and
400  * starting at index @index.
401  *
402  * If a page is newly created, add it to lru list
403  *
404  * Note, the page locks are obtained in ascending page index order.
405  */
__ntfs_grab_cache_pages(struct address_space * mapping,pgoff_t index,const unsigned nr_pages,struct page ** pages,struct page ** cached_page)406 static inline int __ntfs_grab_cache_pages(struct address_space *mapping,
407 		pgoff_t index, const unsigned nr_pages, struct page **pages,
408 		struct page **cached_page)
409 {
410 	int err, nr;
411 
412 	BUG_ON(!nr_pages);
413 	err = nr = 0;
414 	do {
415 		pages[nr] = find_lock_page(mapping, index);
416 		if (!pages[nr]) {
417 			if (!*cached_page) {
418 				*cached_page = page_cache_alloc(mapping);
419 				if (unlikely(!*cached_page)) {
420 					err = -ENOMEM;
421 					goto err_out;
422 				}
423 			}
424 			err = add_to_page_cache_lru(*cached_page, mapping, index,
425 					GFP_KERNEL);
426 			if (unlikely(err)) {
427 				if (err == -EEXIST)
428 					continue;
429 				goto err_out;
430 			}
431 			pages[nr] = *cached_page;
432 			*cached_page = NULL;
433 		}
434 		index++;
435 		nr++;
436 	} while (nr < nr_pages);
437 out:
438 	return err;
439 err_out:
440 	while (nr > 0) {
441 		unlock_page(pages[--nr]);
442 		page_cache_release(pages[nr]);
443 	}
444 	goto out;
445 }
446 
ntfs_submit_bh_for_read(struct buffer_head * bh)447 static inline int ntfs_submit_bh_for_read(struct buffer_head *bh)
448 {
449 	lock_buffer(bh);
450 	get_bh(bh);
451 	bh->b_end_io = end_buffer_read_sync;
452 	return submit_bh(READ, bh);
453 }
454 
455 /**
456  * ntfs_prepare_pages_for_non_resident_write - prepare pages for receiving data
457  * @pages:	array of destination pages
458  * @nr_pages:	number of pages in @pages
459  * @pos:	byte position in file at which the write begins
460  * @bytes:	number of bytes to be written
461  *
462  * This is called for non-resident attributes from ntfs_file_buffered_write()
463  * with i_mutex held on the inode (@pages[0]->mapping->host).  There are
464  * @nr_pages pages in @pages which are locked but not kmap()ped.  The source
465  * data has not yet been copied into the @pages.
466  *
467  * Need to fill any holes with actual clusters, allocate buffers if necessary,
468  * ensure all the buffers are mapped, and bring uptodate any buffers that are
469  * only partially being written to.
470  *
471  * If @nr_pages is greater than one, we are guaranteed that the cluster size is
472  * greater than PAGE_CACHE_SIZE, that all pages in @pages are entirely inside
473  * the same cluster and that they are the entirety of that cluster, and that
474  * the cluster is sparse, i.e. we need to allocate a cluster to fill the hole.
475  *
476  * i_size is not to be modified yet.
477  *
478  * Return 0 on success or -errno on error.
479  */
ntfs_prepare_pages_for_non_resident_write(struct page ** pages,unsigned nr_pages,s64 pos,size_t bytes)480 static int ntfs_prepare_pages_for_non_resident_write(struct page **pages,
481 		unsigned nr_pages, s64 pos, size_t bytes)
482 {
483 	VCN vcn, highest_vcn = 0, cpos, cend, bh_cpos, bh_cend;
484 	LCN lcn;
485 	s64 bh_pos, vcn_len, end, initialized_size;
486 	sector_t lcn_block;
487 	struct page *page;
488 	struct inode *vi;
489 	ntfs_inode *ni, *base_ni = NULL;
490 	ntfs_volume *vol;
491 	runlist_element *rl, *rl2;
492 	struct buffer_head *bh, *head, *wait[2], **wait_bh = wait;
493 	ntfs_attr_search_ctx *ctx = NULL;
494 	MFT_RECORD *m = NULL;
495 	ATTR_RECORD *a = NULL;
496 	unsigned long flags;
497 	u32 attr_rec_len = 0;
498 	unsigned blocksize, u;
499 	int err, mp_size;
500 	bool rl_write_locked, was_hole, is_retry;
501 	unsigned char blocksize_bits;
502 	struct {
503 		u8 runlist_merged:1;
504 		u8 mft_attr_mapped:1;
505 		u8 mp_rebuilt:1;
506 		u8 attr_switched:1;
507 	} status = { 0, 0, 0, 0 };
508 
509 	BUG_ON(!nr_pages);
510 	BUG_ON(!pages);
511 	BUG_ON(!*pages);
512 	vi = pages[0]->mapping->host;
513 	ni = NTFS_I(vi);
514 	vol = ni->vol;
515 	ntfs_debug("Entering for inode 0x%lx, attribute type 0x%x, start page "
516 			"index 0x%lx, nr_pages 0x%x, pos 0x%llx, bytes 0x%zx.",
517 			vi->i_ino, ni->type, pages[0]->index, nr_pages,
518 			(long long)pos, bytes);
519 	blocksize = vol->sb->s_blocksize;
520 	blocksize_bits = vol->sb->s_blocksize_bits;
521 	u = 0;
522 	do {
523 		page = pages[u];
524 		BUG_ON(!page);
525 		/*
526 		 * create_empty_buffers() will create uptodate/dirty buffers if
527 		 * the page is uptodate/dirty.
528 		 */
529 		if (!page_has_buffers(page)) {
530 			create_empty_buffers(page, blocksize, 0);
531 			if (unlikely(!page_has_buffers(page)))
532 				return -ENOMEM;
533 		}
534 	} while (++u < nr_pages);
535 	rl_write_locked = false;
536 	rl = NULL;
537 	err = 0;
538 	vcn = lcn = -1;
539 	vcn_len = 0;
540 	lcn_block = -1;
541 	was_hole = false;
542 	cpos = pos >> vol->cluster_size_bits;
543 	end = pos + bytes;
544 	cend = (end + vol->cluster_size - 1) >> vol->cluster_size_bits;
545 	/*
546 	 * Loop over each page and for each page over each buffer.  Use goto to
547 	 * reduce indentation.
548 	 */
549 	u = 0;
550 do_next_page:
551 	page = pages[u];
552 	bh_pos = (s64)page->index << PAGE_CACHE_SHIFT;
553 	bh = head = page_buffers(page);
554 	do {
555 		VCN cdelta;
556 		s64 bh_end;
557 		unsigned bh_cofs;
558 
559 		/* Clear buffer_new on all buffers to reinitialise state. */
560 		if (buffer_new(bh))
561 			clear_buffer_new(bh);
562 		bh_end = bh_pos + blocksize;
563 		bh_cpos = bh_pos >> vol->cluster_size_bits;
564 		bh_cofs = bh_pos & vol->cluster_size_mask;
565 		if (buffer_mapped(bh)) {
566 			/*
567 			 * The buffer is already mapped.  If it is uptodate,
568 			 * ignore it.
569 			 */
570 			if (buffer_uptodate(bh))
571 				continue;
572 			/*
573 			 * The buffer is not uptodate.  If the page is uptodate
574 			 * set the buffer uptodate and otherwise ignore it.
575 			 */
576 			if (PageUptodate(page)) {
577 				set_buffer_uptodate(bh);
578 				continue;
579 			}
580 			/*
581 			 * Neither the page nor the buffer are uptodate.  If
582 			 * the buffer is only partially being written to, we
583 			 * need to read it in before the write, i.e. now.
584 			 */
585 			if ((bh_pos < pos && bh_end > pos) ||
586 					(bh_pos < end && bh_end > end)) {
587 				/*
588 				 * If the buffer is fully or partially within
589 				 * the initialized size, do an actual read.
590 				 * Otherwise, simply zero the buffer.
591 				 */
592 				read_lock_irqsave(&ni->size_lock, flags);
593 				initialized_size = ni->initialized_size;
594 				read_unlock_irqrestore(&ni->size_lock, flags);
595 				if (bh_pos < initialized_size) {
596 					ntfs_submit_bh_for_read(bh);
597 					*wait_bh++ = bh;
598 				} else {
599 					zero_user(page, bh_offset(bh),
600 							blocksize);
601 					set_buffer_uptodate(bh);
602 				}
603 			}
604 			continue;
605 		}
606 		/* Unmapped buffer.  Need to map it. */
607 		bh->b_bdev = vol->sb->s_bdev;
608 		/*
609 		 * If the current buffer is in the same clusters as the map
610 		 * cache, there is no need to check the runlist again.  The
611 		 * map cache is made up of @vcn, which is the first cached file
612 		 * cluster, @vcn_len which is the number of cached file
613 		 * clusters, @lcn is the device cluster corresponding to @vcn,
614 		 * and @lcn_block is the block number corresponding to @lcn.
615 		 */
616 		cdelta = bh_cpos - vcn;
617 		if (likely(!cdelta || (cdelta > 0 && cdelta < vcn_len))) {
618 map_buffer_cached:
619 			BUG_ON(lcn < 0);
620 			bh->b_blocknr = lcn_block +
621 					(cdelta << (vol->cluster_size_bits -
622 					blocksize_bits)) +
623 					(bh_cofs >> blocksize_bits);
624 			set_buffer_mapped(bh);
625 			/*
626 			 * If the page is uptodate so is the buffer.  If the
627 			 * buffer is fully outside the write, we ignore it if
628 			 * it was already allocated and we mark it dirty so it
629 			 * gets written out if we allocated it.  On the other
630 			 * hand, if we allocated the buffer but we are not
631 			 * marking it dirty we set buffer_new so we can do
632 			 * error recovery.
633 			 */
634 			if (PageUptodate(page)) {
635 				if (!buffer_uptodate(bh))
636 					set_buffer_uptodate(bh);
637 				if (unlikely(was_hole)) {
638 					/* We allocated the buffer. */
639 					unmap_underlying_metadata(bh->b_bdev,
640 							bh->b_blocknr);
641 					if (bh_end <= pos || bh_pos >= end)
642 						mark_buffer_dirty(bh);
643 					else
644 						set_buffer_new(bh);
645 				}
646 				continue;
647 			}
648 			/* Page is _not_ uptodate. */
649 			if (likely(!was_hole)) {
650 				/*
651 				 * Buffer was already allocated.  If it is not
652 				 * uptodate and is only partially being written
653 				 * to, we need to read it in before the write,
654 				 * i.e. now.
655 				 */
656 				if (!buffer_uptodate(bh) && bh_pos < end &&
657 						bh_end > pos &&
658 						(bh_pos < pos ||
659 						bh_end > end)) {
660 					/*
661 					 * If the buffer is fully or partially
662 					 * within the initialized size, do an
663 					 * actual read.  Otherwise, simply zero
664 					 * the buffer.
665 					 */
666 					read_lock_irqsave(&ni->size_lock,
667 							flags);
668 					initialized_size = ni->initialized_size;
669 					read_unlock_irqrestore(&ni->size_lock,
670 							flags);
671 					if (bh_pos < initialized_size) {
672 						ntfs_submit_bh_for_read(bh);
673 						*wait_bh++ = bh;
674 					} else {
675 						zero_user(page, bh_offset(bh),
676 								blocksize);
677 						set_buffer_uptodate(bh);
678 					}
679 				}
680 				continue;
681 			}
682 			/* We allocated the buffer. */
683 			unmap_underlying_metadata(bh->b_bdev, bh->b_blocknr);
684 			/*
685 			 * If the buffer is fully outside the write, zero it,
686 			 * set it uptodate, and mark it dirty so it gets
687 			 * written out.  If it is partially being written to,
688 			 * zero region surrounding the write but leave it to
689 			 * commit write to do anything else.  Finally, if the
690 			 * buffer is fully being overwritten, do nothing.
691 			 */
692 			if (bh_end <= pos || bh_pos >= end) {
693 				if (!buffer_uptodate(bh)) {
694 					zero_user(page, bh_offset(bh),
695 							blocksize);
696 					set_buffer_uptodate(bh);
697 				}
698 				mark_buffer_dirty(bh);
699 				continue;
700 			}
701 			set_buffer_new(bh);
702 			if (!buffer_uptodate(bh) &&
703 					(bh_pos < pos || bh_end > end)) {
704 				u8 *kaddr;
705 				unsigned pofs;
706 
707 				kaddr = kmap_atomic(page);
708 				if (bh_pos < pos) {
709 					pofs = bh_pos & ~PAGE_CACHE_MASK;
710 					memset(kaddr + pofs, 0, pos - bh_pos);
711 				}
712 				if (bh_end > end) {
713 					pofs = end & ~PAGE_CACHE_MASK;
714 					memset(kaddr + pofs, 0, bh_end - end);
715 				}
716 				kunmap_atomic(kaddr);
717 				flush_dcache_page(page);
718 			}
719 			continue;
720 		}
721 		/*
722 		 * Slow path: this is the first buffer in the cluster.  If it
723 		 * is outside allocated size and is not uptodate, zero it and
724 		 * set it uptodate.
725 		 */
726 		read_lock_irqsave(&ni->size_lock, flags);
727 		initialized_size = ni->allocated_size;
728 		read_unlock_irqrestore(&ni->size_lock, flags);
729 		if (bh_pos > initialized_size) {
730 			if (PageUptodate(page)) {
731 				if (!buffer_uptodate(bh))
732 					set_buffer_uptodate(bh);
733 			} else if (!buffer_uptodate(bh)) {
734 				zero_user(page, bh_offset(bh), blocksize);
735 				set_buffer_uptodate(bh);
736 			}
737 			continue;
738 		}
739 		is_retry = false;
740 		if (!rl) {
741 			down_read(&ni->runlist.lock);
742 retry_remap:
743 			rl = ni->runlist.rl;
744 		}
745 		if (likely(rl != NULL)) {
746 			/* Seek to element containing target cluster. */
747 			while (rl->length && rl[1].vcn <= bh_cpos)
748 				rl++;
749 			lcn = ntfs_rl_vcn_to_lcn(rl, bh_cpos);
750 			if (likely(lcn >= 0)) {
751 				/*
752 				 * Successful remap, setup the map cache and
753 				 * use that to deal with the buffer.
754 				 */
755 				was_hole = false;
756 				vcn = bh_cpos;
757 				vcn_len = rl[1].vcn - vcn;
758 				lcn_block = lcn << (vol->cluster_size_bits -
759 						blocksize_bits);
760 				cdelta = 0;
761 				/*
762 				 * If the number of remaining clusters touched
763 				 * by the write is smaller or equal to the
764 				 * number of cached clusters, unlock the
765 				 * runlist as the map cache will be used from
766 				 * now on.
767 				 */
768 				if (likely(vcn + vcn_len >= cend)) {
769 					if (rl_write_locked) {
770 						up_write(&ni->runlist.lock);
771 						rl_write_locked = false;
772 					} else
773 						up_read(&ni->runlist.lock);
774 					rl = NULL;
775 				}
776 				goto map_buffer_cached;
777 			}
778 		} else
779 			lcn = LCN_RL_NOT_MAPPED;
780 		/*
781 		 * If it is not a hole and not out of bounds, the runlist is
782 		 * probably unmapped so try to map it now.
783 		 */
784 		if (unlikely(lcn != LCN_HOLE && lcn != LCN_ENOENT)) {
785 			if (likely(!is_retry && lcn == LCN_RL_NOT_MAPPED)) {
786 				/* Attempt to map runlist. */
787 				if (!rl_write_locked) {
788 					/*
789 					 * We need the runlist locked for
790 					 * writing, so if it is locked for
791 					 * reading relock it now and retry in
792 					 * case it changed whilst we dropped
793 					 * the lock.
794 					 */
795 					up_read(&ni->runlist.lock);
796 					down_write(&ni->runlist.lock);
797 					rl_write_locked = true;
798 					goto retry_remap;
799 				}
800 				err = ntfs_map_runlist_nolock(ni, bh_cpos,
801 						NULL);
802 				if (likely(!err)) {
803 					is_retry = true;
804 					goto retry_remap;
805 				}
806 				/*
807 				 * If @vcn is out of bounds, pretend @lcn is
808 				 * LCN_ENOENT.  As long as the buffer is out
809 				 * of bounds this will work fine.
810 				 */
811 				if (err == -ENOENT) {
812 					lcn = LCN_ENOENT;
813 					err = 0;
814 					goto rl_not_mapped_enoent;
815 				}
816 			} else
817 				err = -EIO;
818 			/* Failed to map the buffer, even after retrying. */
819 			bh->b_blocknr = -1;
820 			ntfs_error(vol->sb, "Failed to write to inode 0x%lx, "
821 					"attribute type 0x%x, vcn 0x%llx, "
822 					"vcn offset 0x%x, because its "
823 					"location on disk could not be "
824 					"determined%s (error code %i).",
825 					ni->mft_no, ni->type,
826 					(unsigned long long)bh_cpos,
827 					(unsigned)bh_pos &
828 					vol->cluster_size_mask,
829 					is_retry ? " even after retrying" : "",
830 					err);
831 			break;
832 		}
833 rl_not_mapped_enoent:
834 		/*
835 		 * The buffer is in a hole or out of bounds.  We need to fill
836 		 * the hole, unless the buffer is in a cluster which is not
837 		 * touched by the write, in which case we just leave the buffer
838 		 * unmapped.  This can only happen when the cluster size is
839 		 * less than the page cache size.
840 		 */
841 		if (unlikely(vol->cluster_size < PAGE_CACHE_SIZE)) {
842 			bh_cend = (bh_end + vol->cluster_size - 1) >>
843 					vol->cluster_size_bits;
844 			if ((bh_cend <= cpos || bh_cpos >= cend)) {
845 				bh->b_blocknr = -1;
846 				/*
847 				 * If the buffer is uptodate we skip it.  If it
848 				 * is not but the page is uptodate, we can set
849 				 * the buffer uptodate.  If the page is not
850 				 * uptodate, we can clear the buffer and set it
851 				 * uptodate.  Whether this is worthwhile is
852 				 * debatable and this could be removed.
853 				 */
854 				if (PageUptodate(page)) {
855 					if (!buffer_uptodate(bh))
856 						set_buffer_uptodate(bh);
857 				} else if (!buffer_uptodate(bh)) {
858 					zero_user(page, bh_offset(bh),
859 						blocksize);
860 					set_buffer_uptodate(bh);
861 				}
862 				continue;
863 			}
864 		}
865 		/*
866 		 * Out of bounds buffer is invalid if it was not really out of
867 		 * bounds.
868 		 */
869 		BUG_ON(lcn != LCN_HOLE);
870 		/*
871 		 * We need the runlist locked for writing, so if it is locked
872 		 * for reading relock it now and retry in case it changed
873 		 * whilst we dropped the lock.
874 		 */
875 		BUG_ON(!rl);
876 		if (!rl_write_locked) {
877 			up_read(&ni->runlist.lock);
878 			down_write(&ni->runlist.lock);
879 			rl_write_locked = true;
880 			goto retry_remap;
881 		}
882 		/* Find the previous last allocated cluster. */
883 		BUG_ON(rl->lcn != LCN_HOLE);
884 		lcn = -1;
885 		rl2 = rl;
886 		while (--rl2 >= ni->runlist.rl) {
887 			if (rl2->lcn >= 0) {
888 				lcn = rl2->lcn + rl2->length;
889 				break;
890 			}
891 		}
892 		rl2 = ntfs_cluster_alloc(vol, bh_cpos, 1, lcn, DATA_ZONE,
893 				false);
894 		if (IS_ERR(rl2)) {
895 			err = PTR_ERR(rl2);
896 			ntfs_debug("Failed to allocate cluster, error code %i.",
897 					err);
898 			break;
899 		}
900 		lcn = rl2->lcn;
901 		rl = ntfs_runlists_merge(ni->runlist.rl, rl2);
902 		if (IS_ERR(rl)) {
903 			err = PTR_ERR(rl);
904 			if (err != -ENOMEM)
905 				err = -EIO;
906 			if (ntfs_cluster_free_from_rl(vol, rl2)) {
907 				ntfs_error(vol->sb, "Failed to release "
908 						"allocated cluster in error "
909 						"code path.  Run chkdsk to "
910 						"recover the lost cluster.");
911 				NVolSetErrors(vol);
912 			}
913 			ntfs_free(rl2);
914 			break;
915 		}
916 		ni->runlist.rl = rl;
917 		status.runlist_merged = 1;
918 		ntfs_debug("Allocated cluster, lcn 0x%llx.",
919 				(unsigned long long)lcn);
920 		/* Map and lock the mft record and get the attribute record. */
921 		if (!NInoAttr(ni))
922 			base_ni = ni;
923 		else
924 			base_ni = ni->ext.base_ntfs_ino;
925 		m = map_mft_record(base_ni);
926 		if (IS_ERR(m)) {
927 			err = PTR_ERR(m);
928 			break;
929 		}
930 		ctx = ntfs_attr_get_search_ctx(base_ni, m);
931 		if (unlikely(!ctx)) {
932 			err = -ENOMEM;
933 			unmap_mft_record(base_ni);
934 			break;
935 		}
936 		status.mft_attr_mapped = 1;
937 		err = ntfs_attr_lookup(ni->type, ni->name, ni->name_len,
938 				CASE_SENSITIVE, bh_cpos, NULL, 0, ctx);
939 		if (unlikely(err)) {
940 			if (err == -ENOENT)
941 				err = -EIO;
942 			break;
943 		}
944 		m = ctx->mrec;
945 		a = ctx->attr;
946 		/*
947 		 * Find the runlist element with which the attribute extent
948 		 * starts.  Note, we cannot use the _attr_ version because we
949 		 * have mapped the mft record.  That is ok because we know the
950 		 * runlist fragment must be mapped already to have ever gotten
951 		 * here, so we can just use the _rl_ version.
952 		 */
953 		vcn = sle64_to_cpu(a->data.non_resident.lowest_vcn);
954 		rl2 = ntfs_rl_find_vcn_nolock(rl, vcn);
955 		BUG_ON(!rl2);
956 		BUG_ON(!rl2->length);
957 		BUG_ON(rl2->lcn < LCN_HOLE);
958 		highest_vcn = sle64_to_cpu(a->data.non_resident.highest_vcn);
959 		/*
960 		 * If @highest_vcn is zero, calculate the real highest_vcn
961 		 * (which can really be zero).
962 		 */
963 		if (!highest_vcn)
964 			highest_vcn = (sle64_to_cpu(
965 					a->data.non_resident.allocated_size) >>
966 					vol->cluster_size_bits) - 1;
967 		/*
968 		 * Determine the size of the mapping pairs array for the new
969 		 * extent, i.e. the old extent with the hole filled.
970 		 */
971 		mp_size = ntfs_get_size_for_mapping_pairs(vol, rl2, vcn,
972 				highest_vcn);
973 		if (unlikely(mp_size <= 0)) {
974 			if (!(err = mp_size))
975 				err = -EIO;
976 			ntfs_debug("Failed to get size for mapping pairs "
977 					"array, error code %i.", err);
978 			break;
979 		}
980 		/*
981 		 * Resize the attribute record to fit the new mapping pairs
982 		 * array.
983 		 */
984 		attr_rec_len = le32_to_cpu(a->length);
985 		err = ntfs_attr_record_resize(m, a, mp_size + le16_to_cpu(
986 				a->data.non_resident.mapping_pairs_offset));
987 		if (unlikely(err)) {
988 			BUG_ON(err != -ENOSPC);
989 			// TODO: Deal with this by using the current attribute
990 			// and fill it with as much of the mapping pairs
991 			// array as possible.  Then loop over each attribute
992 			// extent rewriting the mapping pairs arrays as we go
993 			// along and if when we reach the end we have not
994 			// enough space, try to resize the last attribute
995 			// extent and if even that fails, add a new attribute
996 			// extent.
997 			// We could also try to resize at each step in the hope
998 			// that we will not need to rewrite every single extent.
999 			// Note, we may need to decompress some extents to fill
1000 			// the runlist as we are walking the extents...
1001 			ntfs_error(vol->sb, "Not enough space in the mft "
1002 					"record for the extended attribute "
1003 					"record.  This case is not "
1004 					"implemented yet.");
1005 			err = -EOPNOTSUPP;
1006 			break ;
1007 		}
1008 		status.mp_rebuilt = 1;
1009 		/*
1010 		 * Generate the mapping pairs array directly into the attribute
1011 		 * record.
1012 		 */
1013 		err = ntfs_mapping_pairs_build(vol, (u8*)a + le16_to_cpu(
1014 				a->data.non_resident.mapping_pairs_offset),
1015 				mp_size, rl2, vcn, highest_vcn, NULL);
1016 		if (unlikely(err)) {
1017 			ntfs_error(vol->sb, "Cannot fill hole in inode 0x%lx, "
1018 					"attribute type 0x%x, because building "
1019 					"the mapping pairs failed with error "
1020 					"code %i.", vi->i_ino,
1021 					(unsigned)le32_to_cpu(ni->type), err);
1022 			err = -EIO;
1023 			break;
1024 		}
1025 		/* Update the highest_vcn but only if it was not set. */
1026 		if (unlikely(!a->data.non_resident.highest_vcn))
1027 			a->data.non_resident.highest_vcn =
1028 					cpu_to_sle64(highest_vcn);
1029 		/*
1030 		 * If the attribute is sparse/compressed, update the compressed
1031 		 * size in the ntfs_inode structure and the attribute record.
1032 		 */
1033 		if (likely(NInoSparse(ni) || NInoCompressed(ni))) {
1034 			/*
1035 			 * If we are not in the first attribute extent, switch
1036 			 * to it, but first ensure the changes will make it to
1037 			 * disk later.
1038 			 */
1039 			if (a->data.non_resident.lowest_vcn) {
1040 				flush_dcache_mft_record_page(ctx->ntfs_ino);
1041 				mark_mft_record_dirty(ctx->ntfs_ino);
1042 				ntfs_attr_reinit_search_ctx(ctx);
1043 				err = ntfs_attr_lookup(ni->type, ni->name,
1044 						ni->name_len, CASE_SENSITIVE,
1045 						0, NULL, 0, ctx);
1046 				if (unlikely(err)) {
1047 					status.attr_switched = 1;
1048 					break;
1049 				}
1050 				/* @m is not used any more so do not set it. */
1051 				a = ctx->attr;
1052 			}
1053 			write_lock_irqsave(&ni->size_lock, flags);
1054 			ni->itype.compressed.size += vol->cluster_size;
1055 			a->data.non_resident.compressed_size =
1056 					cpu_to_sle64(ni->itype.compressed.size);
1057 			write_unlock_irqrestore(&ni->size_lock, flags);
1058 		}
1059 		/* Ensure the changes make it to disk. */
1060 		flush_dcache_mft_record_page(ctx->ntfs_ino);
1061 		mark_mft_record_dirty(ctx->ntfs_ino);
1062 		ntfs_attr_put_search_ctx(ctx);
1063 		unmap_mft_record(base_ni);
1064 		/* Successfully filled the hole. */
1065 		status.runlist_merged = 0;
1066 		status.mft_attr_mapped = 0;
1067 		status.mp_rebuilt = 0;
1068 		/* Setup the map cache and use that to deal with the buffer. */
1069 		was_hole = true;
1070 		vcn = bh_cpos;
1071 		vcn_len = 1;
1072 		lcn_block = lcn << (vol->cluster_size_bits - blocksize_bits);
1073 		cdelta = 0;
1074 		/*
1075 		 * If the number of remaining clusters in the @pages is smaller
1076 		 * or equal to the number of cached clusters, unlock the
1077 		 * runlist as the map cache will be used from now on.
1078 		 */
1079 		if (likely(vcn + vcn_len >= cend)) {
1080 			up_write(&ni->runlist.lock);
1081 			rl_write_locked = false;
1082 			rl = NULL;
1083 		}
1084 		goto map_buffer_cached;
1085 	} while (bh_pos += blocksize, (bh = bh->b_this_page) != head);
1086 	/* If there are no errors, do the next page. */
1087 	if (likely(!err && ++u < nr_pages))
1088 		goto do_next_page;
1089 	/* If there are no errors, release the runlist lock if we took it. */
1090 	if (likely(!err)) {
1091 		if (unlikely(rl_write_locked)) {
1092 			up_write(&ni->runlist.lock);
1093 			rl_write_locked = false;
1094 		} else if (unlikely(rl))
1095 			up_read(&ni->runlist.lock);
1096 		rl = NULL;
1097 	}
1098 	/* If we issued read requests, let them complete. */
1099 	read_lock_irqsave(&ni->size_lock, flags);
1100 	initialized_size = ni->initialized_size;
1101 	read_unlock_irqrestore(&ni->size_lock, flags);
1102 	while (wait_bh > wait) {
1103 		bh = *--wait_bh;
1104 		wait_on_buffer(bh);
1105 		if (likely(buffer_uptodate(bh))) {
1106 			page = bh->b_page;
1107 			bh_pos = ((s64)page->index << PAGE_CACHE_SHIFT) +
1108 					bh_offset(bh);
1109 			/*
1110 			 * If the buffer overflows the initialized size, need
1111 			 * to zero the overflowing region.
1112 			 */
1113 			if (unlikely(bh_pos + blocksize > initialized_size)) {
1114 				int ofs = 0;
1115 
1116 				if (likely(bh_pos < initialized_size))
1117 					ofs = initialized_size - bh_pos;
1118 				zero_user_segment(page, bh_offset(bh) + ofs,
1119 						blocksize);
1120 			}
1121 		} else /* if (unlikely(!buffer_uptodate(bh))) */
1122 			err = -EIO;
1123 	}
1124 	if (likely(!err)) {
1125 		/* Clear buffer_new on all buffers. */
1126 		u = 0;
1127 		do {
1128 			bh = head = page_buffers(pages[u]);
1129 			do {
1130 				if (buffer_new(bh))
1131 					clear_buffer_new(bh);
1132 			} while ((bh = bh->b_this_page) != head);
1133 		} while (++u < nr_pages);
1134 		ntfs_debug("Done.");
1135 		return err;
1136 	}
1137 	if (status.attr_switched) {
1138 		/* Get back to the attribute extent we modified. */
1139 		ntfs_attr_reinit_search_ctx(ctx);
1140 		if (ntfs_attr_lookup(ni->type, ni->name, ni->name_len,
1141 				CASE_SENSITIVE, bh_cpos, NULL, 0, ctx)) {
1142 			ntfs_error(vol->sb, "Failed to find required "
1143 					"attribute extent of attribute in "
1144 					"error code path.  Run chkdsk to "
1145 					"recover.");
1146 			write_lock_irqsave(&ni->size_lock, flags);
1147 			ni->itype.compressed.size += vol->cluster_size;
1148 			write_unlock_irqrestore(&ni->size_lock, flags);
1149 			flush_dcache_mft_record_page(ctx->ntfs_ino);
1150 			mark_mft_record_dirty(ctx->ntfs_ino);
1151 			/*
1152 			 * The only thing that is now wrong is the compressed
1153 			 * size of the base attribute extent which chkdsk
1154 			 * should be able to fix.
1155 			 */
1156 			NVolSetErrors(vol);
1157 		} else {
1158 			m = ctx->mrec;
1159 			a = ctx->attr;
1160 			status.attr_switched = 0;
1161 		}
1162 	}
1163 	/*
1164 	 * If the runlist has been modified, need to restore it by punching a
1165 	 * hole into it and we then need to deallocate the on-disk cluster as
1166 	 * well.  Note, we only modify the runlist if we are able to generate a
1167 	 * new mapping pairs array, i.e. only when the mapped attribute extent
1168 	 * is not switched.
1169 	 */
1170 	if (status.runlist_merged && !status.attr_switched) {
1171 		BUG_ON(!rl_write_locked);
1172 		/* Make the file cluster we allocated sparse in the runlist. */
1173 		if (ntfs_rl_punch_nolock(vol, &ni->runlist, bh_cpos, 1)) {
1174 			ntfs_error(vol->sb, "Failed to punch hole into "
1175 					"attribute runlist in error code "
1176 					"path.  Run chkdsk to recover the "
1177 					"lost cluster.");
1178 			NVolSetErrors(vol);
1179 		} else /* if (success) */ {
1180 			status.runlist_merged = 0;
1181 			/*
1182 			 * Deallocate the on-disk cluster we allocated but only
1183 			 * if we succeeded in punching its vcn out of the
1184 			 * runlist.
1185 			 */
1186 			down_write(&vol->lcnbmp_lock);
1187 			if (ntfs_bitmap_clear_bit(vol->lcnbmp_ino, lcn)) {
1188 				ntfs_error(vol->sb, "Failed to release "
1189 						"allocated cluster in error "
1190 						"code path.  Run chkdsk to "
1191 						"recover the lost cluster.");
1192 				NVolSetErrors(vol);
1193 			}
1194 			up_write(&vol->lcnbmp_lock);
1195 		}
1196 	}
1197 	/*
1198 	 * Resize the attribute record to its old size and rebuild the mapping
1199 	 * pairs array.  Note, we only can do this if the runlist has been
1200 	 * restored to its old state which also implies that the mapped
1201 	 * attribute extent is not switched.
1202 	 */
1203 	if (status.mp_rebuilt && !status.runlist_merged) {
1204 		if (ntfs_attr_record_resize(m, a, attr_rec_len)) {
1205 			ntfs_error(vol->sb, "Failed to restore attribute "
1206 					"record in error code path.  Run "
1207 					"chkdsk to recover.");
1208 			NVolSetErrors(vol);
1209 		} else /* if (success) */ {
1210 			if (ntfs_mapping_pairs_build(vol, (u8*)a +
1211 					le16_to_cpu(a->data.non_resident.
1212 					mapping_pairs_offset), attr_rec_len -
1213 					le16_to_cpu(a->data.non_resident.
1214 					mapping_pairs_offset), ni->runlist.rl,
1215 					vcn, highest_vcn, NULL)) {
1216 				ntfs_error(vol->sb, "Failed to restore "
1217 						"mapping pairs array in error "
1218 						"code path.  Run chkdsk to "
1219 						"recover.");
1220 				NVolSetErrors(vol);
1221 			}
1222 			flush_dcache_mft_record_page(ctx->ntfs_ino);
1223 			mark_mft_record_dirty(ctx->ntfs_ino);
1224 		}
1225 	}
1226 	/* Release the mft record and the attribute. */
1227 	if (status.mft_attr_mapped) {
1228 		ntfs_attr_put_search_ctx(ctx);
1229 		unmap_mft_record(base_ni);
1230 	}
1231 	/* Release the runlist lock. */
1232 	if (rl_write_locked)
1233 		up_write(&ni->runlist.lock);
1234 	else if (rl)
1235 		up_read(&ni->runlist.lock);
1236 	/*
1237 	 * Zero out any newly allocated blocks to avoid exposing stale data.
1238 	 * If BH_New is set, we know that the block was newly allocated above
1239 	 * and that it has not been fully zeroed and marked dirty yet.
1240 	 */
1241 	nr_pages = u;
1242 	u = 0;
1243 	end = bh_cpos << vol->cluster_size_bits;
1244 	do {
1245 		page = pages[u];
1246 		bh = head = page_buffers(page);
1247 		do {
1248 			if (u == nr_pages &&
1249 					((s64)page->index << PAGE_CACHE_SHIFT) +
1250 					bh_offset(bh) >= end)
1251 				break;
1252 			if (!buffer_new(bh))
1253 				continue;
1254 			clear_buffer_new(bh);
1255 			if (!buffer_uptodate(bh)) {
1256 				if (PageUptodate(page))
1257 					set_buffer_uptodate(bh);
1258 				else {
1259 					zero_user(page, bh_offset(bh),
1260 							blocksize);
1261 					set_buffer_uptodate(bh);
1262 				}
1263 			}
1264 			mark_buffer_dirty(bh);
1265 		} while ((bh = bh->b_this_page) != head);
1266 	} while (++u <= nr_pages);
1267 	ntfs_error(vol->sb, "Failed.  Returning error code %i.", err);
1268 	return err;
1269 }
1270 
1271 /*
1272  * Copy as much as we can into the pages and return the number of bytes which
1273  * were successfully copied.  If a fault is encountered then clear the pages
1274  * out to (ofs + bytes) and return the number of bytes which were copied.
1275  */
ntfs_copy_from_user(struct page ** pages,unsigned nr_pages,unsigned ofs,const char __user * buf,size_t bytes)1276 static inline size_t ntfs_copy_from_user(struct page **pages,
1277 		unsigned nr_pages, unsigned ofs, const char __user *buf,
1278 		size_t bytes)
1279 {
1280 	struct page **last_page = pages + nr_pages;
1281 	char *addr;
1282 	size_t total = 0;
1283 	unsigned len;
1284 	int left;
1285 
1286 	do {
1287 		len = PAGE_CACHE_SIZE - ofs;
1288 		if (len > bytes)
1289 			len = bytes;
1290 		addr = kmap_atomic(*pages);
1291 		left = __copy_from_user_inatomic(addr + ofs, buf, len);
1292 		kunmap_atomic(addr);
1293 		if (unlikely(left)) {
1294 			/* Do it the slow way. */
1295 			addr = kmap(*pages);
1296 			left = __copy_from_user(addr + ofs, buf, len);
1297 			kunmap(*pages);
1298 			if (unlikely(left))
1299 				goto err_out;
1300 		}
1301 		total += len;
1302 		bytes -= len;
1303 		if (!bytes)
1304 			break;
1305 		buf += len;
1306 		ofs = 0;
1307 	} while (++pages < last_page);
1308 out:
1309 	return total;
1310 err_out:
1311 	total += len - left;
1312 	/* Zero the rest of the target like __copy_from_user(). */
1313 	while (++pages < last_page) {
1314 		bytes -= len;
1315 		if (!bytes)
1316 			break;
1317 		len = PAGE_CACHE_SIZE;
1318 		if (len > bytes)
1319 			len = bytes;
1320 		zero_user(*pages, 0, len);
1321 	}
1322 	goto out;
1323 }
1324 
__ntfs_copy_from_user_iovec_inatomic(char * vaddr,const struct iovec * iov,size_t iov_ofs,size_t bytes)1325 static size_t __ntfs_copy_from_user_iovec_inatomic(char *vaddr,
1326 		const struct iovec *iov, size_t iov_ofs, size_t bytes)
1327 {
1328 	size_t total = 0;
1329 
1330 	while (1) {
1331 		const char __user *buf = iov->iov_base + iov_ofs;
1332 		unsigned len;
1333 		size_t left;
1334 
1335 		len = iov->iov_len - iov_ofs;
1336 		if (len > bytes)
1337 			len = bytes;
1338 		left = __copy_from_user_inatomic(vaddr, buf, len);
1339 		total += len;
1340 		bytes -= len;
1341 		vaddr += len;
1342 		if (unlikely(left)) {
1343 			total -= left;
1344 			break;
1345 		}
1346 		if (!bytes)
1347 			break;
1348 		iov++;
1349 		iov_ofs = 0;
1350 	}
1351 	return total;
1352 }
1353 
ntfs_set_next_iovec(const struct iovec ** iovp,size_t * iov_ofsp,size_t bytes)1354 static inline void ntfs_set_next_iovec(const struct iovec **iovp,
1355 		size_t *iov_ofsp, size_t bytes)
1356 {
1357 	const struct iovec *iov = *iovp;
1358 	size_t iov_ofs = *iov_ofsp;
1359 
1360 	while (bytes) {
1361 		unsigned len;
1362 
1363 		len = iov->iov_len - iov_ofs;
1364 		if (len > bytes)
1365 			len = bytes;
1366 		bytes -= len;
1367 		iov_ofs += len;
1368 		if (iov->iov_len == iov_ofs) {
1369 			iov++;
1370 			iov_ofs = 0;
1371 		}
1372 	}
1373 	*iovp = iov;
1374 	*iov_ofsp = iov_ofs;
1375 }
1376 
1377 /*
1378  * This has the same side-effects and return value as ntfs_copy_from_user().
1379  * The difference is that on a fault we need to memset the remainder of the
1380  * pages (out to offset + bytes), to emulate ntfs_copy_from_user()'s
1381  * single-segment behaviour.
1382  *
1383  * We call the same helper (__ntfs_copy_from_user_iovec_inatomic()) both when
1384  * atomic and when not atomic.  This is ok because it calls
1385  * __copy_from_user_inatomic() and it is ok to call this when non-atomic.  In
1386  * fact, the only difference between __copy_from_user_inatomic() and
1387  * __copy_from_user() is that the latter calls might_sleep() and the former
1388  * should not zero the tail of the buffer on error.  And on many architectures
1389  * __copy_from_user_inatomic() is just defined to __copy_from_user() so it
1390  * makes no difference at all on those architectures.
1391  */
ntfs_copy_from_user_iovec(struct page ** pages,unsigned nr_pages,unsigned ofs,const struct iovec ** iov,size_t * iov_ofs,size_t bytes)1392 static inline size_t ntfs_copy_from_user_iovec(struct page **pages,
1393 		unsigned nr_pages, unsigned ofs, const struct iovec **iov,
1394 		size_t *iov_ofs, size_t bytes)
1395 {
1396 	struct page **last_page = pages + nr_pages;
1397 	char *addr;
1398 	size_t copied, len, total = 0;
1399 
1400 	do {
1401 		len = PAGE_CACHE_SIZE - ofs;
1402 		if (len > bytes)
1403 			len = bytes;
1404 		addr = kmap_atomic(*pages);
1405 		copied = __ntfs_copy_from_user_iovec_inatomic(addr + ofs,
1406 				*iov, *iov_ofs, len);
1407 		kunmap_atomic(addr);
1408 		if (unlikely(copied != len)) {
1409 			/* Do it the slow way. */
1410 			addr = kmap(*pages);
1411 			copied = __ntfs_copy_from_user_iovec_inatomic(addr +
1412 					ofs, *iov, *iov_ofs, len);
1413 			if (unlikely(copied != len))
1414 				goto err_out;
1415 			kunmap(*pages);
1416 		}
1417 		total += len;
1418 		ntfs_set_next_iovec(iov, iov_ofs, len);
1419 		bytes -= len;
1420 		if (!bytes)
1421 			break;
1422 		ofs = 0;
1423 	} while (++pages < last_page);
1424 out:
1425 	return total;
1426 err_out:
1427 	BUG_ON(copied > len);
1428 	/* Zero the rest of the target like __copy_from_user(). */
1429 	memset(addr + ofs + copied, 0, len - copied);
1430 	kunmap(*pages);
1431 	total += copied;
1432 	ntfs_set_next_iovec(iov, iov_ofs, copied);
1433 	while (++pages < last_page) {
1434 		bytes -= len;
1435 		if (!bytes)
1436 			break;
1437 		len = PAGE_CACHE_SIZE;
1438 		if (len > bytes)
1439 			len = bytes;
1440 		zero_user(*pages, 0, len);
1441 	}
1442 	goto out;
1443 }
1444 
ntfs_flush_dcache_pages(struct page ** pages,unsigned nr_pages)1445 static inline void ntfs_flush_dcache_pages(struct page **pages,
1446 		unsigned nr_pages)
1447 {
1448 	BUG_ON(!nr_pages);
1449 	/*
1450 	 * Warning: Do not do the decrement at the same time as the call to
1451 	 * flush_dcache_page() because it is a NULL macro on i386 and hence the
1452 	 * decrement never happens so the loop never terminates.
1453 	 */
1454 	do {
1455 		--nr_pages;
1456 		flush_dcache_page(pages[nr_pages]);
1457 	} while (nr_pages > 0);
1458 }
1459 
1460 /**
1461  * ntfs_commit_pages_after_non_resident_write - commit the received data
1462  * @pages:	array of destination pages
1463  * @nr_pages:	number of pages in @pages
1464  * @pos:	byte position in file at which the write begins
1465  * @bytes:	number of bytes to be written
1466  *
1467  * See description of ntfs_commit_pages_after_write(), below.
1468  */
ntfs_commit_pages_after_non_resident_write(struct page ** pages,const unsigned nr_pages,s64 pos,size_t bytes)1469 static inline int ntfs_commit_pages_after_non_resident_write(
1470 		struct page **pages, const unsigned nr_pages,
1471 		s64 pos, size_t bytes)
1472 {
1473 	s64 end, initialized_size;
1474 	struct inode *vi;
1475 	ntfs_inode *ni, *base_ni;
1476 	struct buffer_head *bh, *head;
1477 	ntfs_attr_search_ctx *ctx;
1478 	MFT_RECORD *m;
1479 	ATTR_RECORD *a;
1480 	unsigned long flags;
1481 	unsigned blocksize, u;
1482 	int err;
1483 
1484 	vi = pages[0]->mapping->host;
1485 	ni = NTFS_I(vi);
1486 	blocksize = vi->i_sb->s_blocksize;
1487 	end = pos + bytes;
1488 	u = 0;
1489 	do {
1490 		s64 bh_pos;
1491 		struct page *page;
1492 		bool partial;
1493 
1494 		page = pages[u];
1495 		bh_pos = (s64)page->index << PAGE_CACHE_SHIFT;
1496 		bh = head = page_buffers(page);
1497 		partial = false;
1498 		do {
1499 			s64 bh_end;
1500 
1501 			bh_end = bh_pos + blocksize;
1502 			if (bh_end <= pos || bh_pos >= end) {
1503 				if (!buffer_uptodate(bh))
1504 					partial = true;
1505 			} else {
1506 				set_buffer_uptodate(bh);
1507 				mark_buffer_dirty(bh);
1508 			}
1509 		} while (bh_pos += blocksize, (bh = bh->b_this_page) != head);
1510 		/*
1511 		 * If all buffers are now uptodate but the page is not, set the
1512 		 * page uptodate.
1513 		 */
1514 		if (!partial && !PageUptodate(page))
1515 			SetPageUptodate(page);
1516 	} while (++u < nr_pages);
1517 	/*
1518 	 * Finally, if we do not need to update initialized_size or i_size we
1519 	 * are finished.
1520 	 */
1521 	read_lock_irqsave(&ni->size_lock, flags);
1522 	initialized_size = ni->initialized_size;
1523 	read_unlock_irqrestore(&ni->size_lock, flags);
1524 	if (end <= initialized_size) {
1525 		ntfs_debug("Done.");
1526 		return 0;
1527 	}
1528 	/*
1529 	 * Update initialized_size/i_size as appropriate, both in the inode and
1530 	 * the mft record.
1531 	 */
1532 	if (!NInoAttr(ni))
1533 		base_ni = ni;
1534 	else
1535 		base_ni = ni->ext.base_ntfs_ino;
1536 	/* Map, pin, and lock the mft record. */
1537 	m = map_mft_record(base_ni);
1538 	if (IS_ERR(m)) {
1539 		err = PTR_ERR(m);
1540 		m = NULL;
1541 		ctx = NULL;
1542 		goto err_out;
1543 	}
1544 	BUG_ON(!NInoNonResident(ni));
1545 	ctx = ntfs_attr_get_search_ctx(base_ni, m);
1546 	if (unlikely(!ctx)) {
1547 		err = -ENOMEM;
1548 		goto err_out;
1549 	}
1550 	err = ntfs_attr_lookup(ni->type, ni->name, ni->name_len,
1551 			CASE_SENSITIVE, 0, NULL, 0, ctx);
1552 	if (unlikely(err)) {
1553 		if (err == -ENOENT)
1554 			err = -EIO;
1555 		goto err_out;
1556 	}
1557 	a = ctx->attr;
1558 	BUG_ON(!a->non_resident);
1559 	write_lock_irqsave(&ni->size_lock, flags);
1560 	BUG_ON(end > ni->allocated_size);
1561 	ni->initialized_size = end;
1562 	a->data.non_resident.initialized_size = cpu_to_sle64(end);
1563 	if (end > i_size_read(vi)) {
1564 		i_size_write(vi, end);
1565 		a->data.non_resident.data_size =
1566 				a->data.non_resident.initialized_size;
1567 	}
1568 	write_unlock_irqrestore(&ni->size_lock, flags);
1569 	/* Mark the mft record dirty, so it gets written back. */
1570 	flush_dcache_mft_record_page(ctx->ntfs_ino);
1571 	mark_mft_record_dirty(ctx->ntfs_ino);
1572 	ntfs_attr_put_search_ctx(ctx);
1573 	unmap_mft_record(base_ni);
1574 	ntfs_debug("Done.");
1575 	return 0;
1576 err_out:
1577 	if (ctx)
1578 		ntfs_attr_put_search_ctx(ctx);
1579 	if (m)
1580 		unmap_mft_record(base_ni);
1581 	ntfs_error(vi->i_sb, "Failed to update initialized_size/i_size (error "
1582 			"code %i).", err);
1583 	if (err != -ENOMEM)
1584 		NVolSetErrors(ni->vol);
1585 	return err;
1586 }
1587 
1588 /**
1589  * ntfs_commit_pages_after_write - commit the received data
1590  * @pages:	array of destination pages
1591  * @nr_pages:	number of pages in @pages
1592  * @pos:	byte position in file at which the write begins
1593  * @bytes:	number of bytes to be written
1594  *
1595  * This is called from ntfs_file_buffered_write() with i_mutex held on the inode
1596  * (@pages[0]->mapping->host).  There are @nr_pages pages in @pages which are
1597  * locked but not kmap()ped.  The source data has already been copied into the
1598  * @page.  ntfs_prepare_pages_for_non_resident_write() has been called before
1599  * the data was copied (for non-resident attributes only) and it returned
1600  * success.
1601  *
1602  * Need to set uptodate and mark dirty all buffers within the boundary of the
1603  * write.  If all buffers in a page are uptodate we set the page uptodate, too.
1604  *
1605  * Setting the buffers dirty ensures that they get written out later when
1606  * ntfs_writepage() is invoked by the VM.
1607  *
1608  * Finally, we need to update i_size and initialized_size as appropriate both
1609  * in the inode and the mft record.
1610  *
1611  * This is modelled after fs/buffer.c::generic_commit_write(), which marks
1612  * buffers uptodate and dirty, sets the page uptodate if all buffers in the
1613  * page are uptodate, and updates i_size if the end of io is beyond i_size.  In
1614  * that case, it also marks the inode dirty.
1615  *
1616  * If things have gone as outlined in
1617  * ntfs_prepare_pages_for_non_resident_write(), we do not need to do any page
1618  * content modifications here for non-resident attributes.  For resident
1619  * attributes we need to do the uptodate bringing here which we combine with
1620  * the copying into the mft record which means we save one atomic kmap.
1621  *
1622  * Return 0 on success or -errno on error.
1623  */
ntfs_commit_pages_after_write(struct page ** pages,const unsigned nr_pages,s64 pos,size_t bytes)1624 static int ntfs_commit_pages_after_write(struct page **pages,
1625 		const unsigned nr_pages, s64 pos, size_t bytes)
1626 {
1627 	s64 end, initialized_size;
1628 	loff_t i_size;
1629 	struct inode *vi;
1630 	ntfs_inode *ni, *base_ni;
1631 	struct page *page;
1632 	ntfs_attr_search_ctx *ctx;
1633 	MFT_RECORD *m;
1634 	ATTR_RECORD *a;
1635 	char *kattr, *kaddr;
1636 	unsigned long flags;
1637 	u32 attr_len;
1638 	int err;
1639 
1640 	BUG_ON(!nr_pages);
1641 	BUG_ON(!pages);
1642 	page = pages[0];
1643 	BUG_ON(!page);
1644 	vi = page->mapping->host;
1645 	ni = NTFS_I(vi);
1646 	ntfs_debug("Entering for inode 0x%lx, attribute type 0x%x, start page "
1647 			"index 0x%lx, nr_pages 0x%x, pos 0x%llx, bytes 0x%zx.",
1648 			vi->i_ino, ni->type, page->index, nr_pages,
1649 			(long long)pos, bytes);
1650 	if (NInoNonResident(ni))
1651 		return ntfs_commit_pages_after_non_resident_write(pages,
1652 				nr_pages, pos, bytes);
1653 	BUG_ON(nr_pages > 1);
1654 	/*
1655 	 * Attribute is resident, implying it is not compressed, encrypted, or
1656 	 * sparse.
1657 	 */
1658 	if (!NInoAttr(ni))
1659 		base_ni = ni;
1660 	else
1661 		base_ni = ni->ext.base_ntfs_ino;
1662 	BUG_ON(NInoNonResident(ni));
1663 	/* Map, pin, and lock the mft record. */
1664 	m = map_mft_record(base_ni);
1665 	if (IS_ERR(m)) {
1666 		err = PTR_ERR(m);
1667 		m = NULL;
1668 		ctx = NULL;
1669 		goto err_out;
1670 	}
1671 	ctx = ntfs_attr_get_search_ctx(base_ni, m);
1672 	if (unlikely(!ctx)) {
1673 		err = -ENOMEM;
1674 		goto err_out;
1675 	}
1676 	err = ntfs_attr_lookup(ni->type, ni->name, ni->name_len,
1677 			CASE_SENSITIVE, 0, NULL, 0, ctx);
1678 	if (unlikely(err)) {
1679 		if (err == -ENOENT)
1680 			err = -EIO;
1681 		goto err_out;
1682 	}
1683 	a = ctx->attr;
1684 	BUG_ON(a->non_resident);
1685 	/* The total length of the attribute value. */
1686 	attr_len = le32_to_cpu(a->data.resident.value_length);
1687 	i_size = i_size_read(vi);
1688 	BUG_ON(attr_len != i_size);
1689 	BUG_ON(pos > attr_len);
1690 	end = pos + bytes;
1691 	BUG_ON(end > le32_to_cpu(a->length) -
1692 			le16_to_cpu(a->data.resident.value_offset));
1693 	kattr = (u8*)a + le16_to_cpu(a->data.resident.value_offset);
1694 	kaddr = kmap_atomic(page);
1695 	/* Copy the received data from the page to the mft record. */
1696 	memcpy(kattr + pos, kaddr + pos, bytes);
1697 	/* Update the attribute length if necessary. */
1698 	if (end > attr_len) {
1699 		attr_len = end;
1700 		a->data.resident.value_length = cpu_to_le32(attr_len);
1701 	}
1702 	/*
1703 	 * If the page is not uptodate, bring the out of bounds area(s)
1704 	 * uptodate by copying data from the mft record to the page.
1705 	 */
1706 	if (!PageUptodate(page)) {
1707 		if (pos > 0)
1708 			memcpy(kaddr, kattr, pos);
1709 		if (end < attr_len)
1710 			memcpy(kaddr + end, kattr + end, attr_len - end);
1711 		/* Zero the region outside the end of the attribute value. */
1712 		memset(kaddr + attr_len, 0, PAGE_CACHE_SIZE - attr_len);
1713 		flush_dcache_page(page);
1714 		SetPageUptodate(page);
1715 	}
1716 	kunmap_atomic(kaddr);
1717 	/* Update initialized_size/i_size if necessary. */
1718 	read_lock_irqsave(&ni->size_lock, flags);
1719 	initialized_size = ni->initialized_size;
1720 	BUG_ON(end > ni->allocated_size);
1721 	read_unlock_irqrestore(&ni->size_lock, flags);
1722 	BUG_ON(initialized_size != i_size);
1723 	if (end > initialized_size) {
1724 		write_lock_irqsave(&ni->size_lock, flags);
1725 		ni->initialized_size = end;
1726 		i_size_write(vi, end);
1727 		write_unlock_irqrestore(&ni->size_lock, flags);
1728 	}
1729 	/* Mark the mft record dirty, so it gets written back. */
1730 	flush_dcache_mft_record_page(ctx->ntfs_ino);
1731 	mark_mft_record_dirty(ctx->ntfs_ino);
1732 	ntfs_attr_put_search_ctx(ctx);
1733 	unmap_mft_record(base_ni);
1734 	ntfs_debug("Done.");
1735 	return 0;
1736 err_out:
1737 	if (err == -ENOMEM) {
1738 		ntfs_warning(vi->i_sb, "Error allocating memory required to "
1739 				"commit the write.");
1740 		if (PageUptodate(page)) {
1741 			ntfs_warning(vi->i_sb, "Page is uptodate, setting "
1742 					"dirty so the write will be retried "
1743 					"later on by the VM.");
1744 			/*
1745 			 * Put the page on mapping->dirty_pages, but leave its
1746 			 * buffers' dirty state as-is.
1747 			 */
1748 			__set_page_dirty_nobuffers(page);
1749 			err = 0;
1750 		} else
1751 			ntfs_error(vi->i_sb, "Page is not uptodate.  Written "
1752 					"data has been lost.");
1753 	} else {
1754 		ntfs_error(vi->i_sb, "Resident attribute commit write failed "
1755 				"with error %i.", err);
1756 		NVolSetErrors(ni->vol);
1757 	}
1758 	if (ctx)
1759 		ntfs_attr_put_search_ctx(ctx);
1760 	if (m)
1761 		unmap_mft_record(base_ni);
1762 	return err;
1763 }
1764 
1765 /**
1766  * ntfs_file_buffered_write -
1767  *
1768  * Locking: The vfs is holding ->i_mutex on the inode.
1769  */
ntfs_file_buffered_write(struct kiocb * iocb,const struct iovec * iov,unsigned long nr_segs,loff_t pos,loff_t * ppos,size_t count)1770 static ssize_t ntfs_file_buffered_write(struct kiocb *iocb,
1771 		const struct iovec *iov, unsigned long nr_segs,
1772 		loff_t pos, loff_t *ppos, size_t count)
1773 {
1774 	struct file *file = iocb->ki_filp;
1775 	struct address_space *mapping = file->f_mapping;
1776 	struct inode *vi = mapping->host;
1777 	ntfs_inode *ni = NTFS_I(vi);
1778 	ntfs_volume *vol = ni->vol;
1779 	struct page *pages[NTFS_MAX_PAGES_PER_CLUSTER];
1780 	struct page *cached_page = NULL;
1781 	char __user *buf = NULL;
1782 	s64 end, ll;
1783 	VCN last_vcn;
1784 	LCN lcn;
1785 	unsigned long flags;
1786 	size_t bytes, iov_ofs = 0;	/* Offset in the current iovec. */
1787 	ssize_t status, written;
1788 	unsigned nr_pages;
1789 	int err;
1790 
1791 	ntfs_debug("Entering for i_ino 0x%lx, attribute type 0x%x, "
1792 			"pos 0x%llx, count 0x%lx.",
1793 			vi->i_ino, (unsigned)le32_to_cpu(ni->type),
1794 			(unsigned long long)pos, (unsigned long)count);
1795 	if (unlikely(!count))
1796 		return 0;
1797 	BUG_ON(NInoMstProtected(ni));
1798 	/*
1799 	 * If the attribute is not an index root and it is encrypted or
1800 	 * compressed, we cannot write to it yet.  Note we need to check for
1801 	 * AT_INDEX_ALLOCATION since this is the type of both directory and
1802 	 * index inodes.
1803 	 */
1804 	if (ni->type != AT_INDEX_ALLOCATION) {
1805 		/* If file is encrypted, deny access, just like NT4. */
1806 		if (NInoEncrypted(ni)) {
1807 			/*
1808 			 * Reminder for later: Encrypted files are _always_
1809 			 * non-resident so that the content can always be
1810 			 * encrypted.
1811 			 */
1812 			ntfs_debug("Denying write access to encrypted file.");
1813 			return -EACCES;
1814 		}
1815 		if (NInoCompressed(ni)) {
1816 			/* Only unnamed $DATA attribute can be compressed. */
1817 			BUG_ON(ni->type != AT_DATA);
1818 			BUG_ON(ni->name_len);
1819 			/*
1820 			 * Reminder for later: If resident, the data is not
1821 			 * actually compressed.  Only on the switch to non-
1822 			 * resident does compression kick in.  This is in
1823 			 * contrast to encrypted files (see above).
1824 			 */
1825 			ntfs_error(vi->i_sb, "Writing to compressed files is "
1826 					"not implemented yet.  Sorry.");
1827 			return -EOPNOTSUPP;
1828 		}
1829 	}
1830 	/*
1831 	 * If a previous ntfs_truncate() failed, repeat it and abort if it
1832 	 * fails again.
1833 	 */
1834 	if (unlikely(NInoTruncateFailed(ni))) {
1835 		inode_dio_wait(vi);
1836 		err = ntfs_truncate(vi);
1837 		if (err || NInoTruncateFailed(ni)) {
1838 			if (!err)
1839 				err = -EIO;
1840 			ntfs_error(vol->sb, "Cannot perform write to inode "
1841 					"0x%lx, attribute type 0x%x, because "
1842 					"ntfs_truncate() failed (error code "
1843 					"%i).", vi->i_ino,
1844 					(unsigned)le32_to_cpu(ni->type), err);
1845 			return err;
1846 		}
1847 	}
1848 	/* The first byte after the write. */
1849 	end = pos + count;
1850 	/*
1851 	 * If the write goes beyond the allocated size, extend the allocation
1852 	 * to cover the whole of the write, rounded up to the nearest cluster.
1853 	 */
1854 	read_lock_irqsave(&ni->size_lock, flags);
1855 	ll = ni->allocated_size;
1856 	read_unlock_irqrestore(&ni->size_lock, flags);
1857 	if (end > ll) {
1858 		/* Extend the allocation without changing the data size. */
1859 		ll = ntfs_attr_extend_allocation(ni, end, -1, pos);
1860 		if (likely(ll >= 0)) {
1861 			BUG_ON(pos >= ll);
1862 			/* If the extension was partial truncate the write. */
1863 			if (end > ll) {
1864 				ntfs_debug("Truncating write to inode 0x%lx, "
1865 						"attribute type 0x%x, because "
1866 						"the allocation was only "
1867 						"partially extended.",
1868 						vi->i_ino, (unsigned)
1869 						le32_to_cpu(ni->type));
1870 				end = ll;
1871 				count = ll - pos;
1872 			}
1873 		} else {
1874 			err = ll;
1875 			read_lock_irqsave(&ni->size_lock, flags);
1876 			ll = ni->allocated_size;
1877 			read_unlock_irqrestore(&ni->size_lock, flags);
1878 			/* Perform a partial write if possible or fail. */
1879 			if (pos < ll) {
1880 				ntfs_debug("Truncating write to inode 0x%lx, "
1881 						"attribute type 0x%x, because "
1882 						"extending the allocation "
1883 						"failed (error code %i).",
1884 						vi->i_ino, (unsigned)
1885 						le32_to_cpu(ni->type), err);
1886 				end = ll;
1887 				count = ll - pos;
1888 			} else {
1889 				ntfs_error(vol->sb, "Cannot perform write to "
1890 						"inode 0x%lx, attribute type "
1891 						"0x%x, because extending the "
1892 						"allocation failed (error "
1893 						"code %i).", vi->i_ino,
1894 						(unsigned)
1895 						le32_to_cpu(ni->type), err);
1896 				return err;
1897 			}
1898 		}
1899 	}
1900 	written = 0;
1901 	/*
1902 	 * If the write starts beyond the initialized size, extend it up to the
1903 	 * beginning of the write and initialize all non-sparse space between
1904 	 * the old initialized size and the new one.  This automatically also
1905 	 * increments the vfs inode->i_size to keep it above or equal to the
1906 	 * initialized_size.
1907 	 */
1908 	read_lock_irqsave(&ni->size_lock, flags);
1909 	ll = ni->initialized_size;
1910 	read_unlock_irqrestore(&ni->size_lock, flags);
1911 	if (pos > ll) {
1912 		err = ntfs_attr_extend_initialized(ni, pos);
1913 		if (err < 0) {
1914 			ntfs_error(vol->sb, "Cannot perform write to inode "
1915 					"0x%lx, attribute type 0x%x, because "
1916 					"extending the initialized size "
1917 					"failed (error code %i).", vi->i_ino,
1918 					(unsigned)le32_to_cpu(ni->type), err);
1919 			status = err;
1920 			goto err_out;
1921 		}
1922 	}
1923 	/*
1924 	 * Determine the number of pages per cluster for non-resident
1925 	 * attributes.
1926 	 */
1927 	nr_pages = 1;
1928 	if (vol->cluster_size > PAGE_CACHE_SIZE && NInoNonResident(ni))
1929 		nr_pages = vol->cluster_size >> PAGE_CACHE_SHIFT;
1930 	/* Finally, perform the actual write. */
1931 	last_vcn = -1;
1932 	if (likely(nr_segs == 1))
1933 		buf = iov->iov_base;
1934 	do {
1935 		VCN vcn;
1936 		pgoff_t idx, start_idx;
1937 		unsigned ofs, do_pages, u;
1938 		size_t copied;
1939 
1940 		start_idx = idx = pos >> PAGE_CACHE_SHIFT;
1941 		ofs = pos & ~PAGE_CACHE_MASK;
1942 		bytes = PAGE_CACHE_SIZE - ofs;
1943 		do_pages = 1;
1944 		if (nr_pages > 1) {
1945 			vcn = pos >> vol->cluster_size_bits;
1946 			if (vcn != last_vcn) {
1947 				last_vcn = vcn;
1948 				/*
1949 				 * Get the lcn of the vcn the write is in.  If
1950 				 * it is a hole, need to lock down all pages in
1951 				 * the cluster.
1952 				 */
1953 				down_read(&ni->runlist.lock);
1954 				lcn = ntfs_attr_vcn_to_lcn_nolock(ni, pos >>
1955 						vol->cluster_size_bits, false);
1956 				up_read(&ni->runlist.lock);
1957 				if (unlikely(lcn < LCN_HOLE)) {
1958 					status = -EIO;
1959 					if (lcn == LCN_ENOMEM)
1960 						status = -ENOMEM;
1961 					else
1962 						ntfs_error(vol->sb, "Cannot "
1963 							"perform write to "
1964 							"inode 0x%lx, "
1965 							"attribute type 0x%x, "
1966 							"because the attribute "
1967 							"is corrupt.",
1968 							vi->i_ino, (unsigned)
1969 							le32_to_cpu(ni->type));
1970 					break;
1971 				}
1972 				if (lcn == LCN_HOLE) {
1973 					start_idx = (pos & ~(s64)
1974 							vol->cluster_size_mask)
1975 							>> PAGE_CACHE_SHIFT;
1976 					bytes = vol->cluster_size - (pos &
1977 							vol->cluster_size_mask);
1978 					do_pages = nr_pages;
1979 				}
1980 			}
1981 		}
1982 		if (bytes > count)
1983 			bytes = count;
1984 		/*
1985 		 * Bring in the user page(s) that we will copy from _first_.
1986 		 * Otherwise there is a nasty deadlock on copying from the same
1987 		 * page(s) as we are writing to, without it/them being marked
1988 		 * up-to-date.  Note, at present there is nothing to stop the
1989 		 * pages being swapped out between us bringing them into memory
1990 		 * and doing the actual copying.
1991 		 */
1992 		if (likely(nr_segs == 1))
1993 			ntfs_fault_in_pages_readable(buf, bytes);
1994 		else
1995 			ntfs_fault_in_pages_readable_iovec(iov, iov_ofs, bytes);
1996 		/* Get and lock @do_pages starting at index @start_idx. */
1997 		status = __ntfs_grab_cache_pages(mapping, start_idx, do_pages,
1998 				pages, &cached_page);
1999 		if (unlikely(status))
2000 			break;
2001 		/*
2002 		 * For non-resident attributes, we need to fill any holes with
2003 		 * actual clusters and ensure all bufferes are mapped.  We also
2004 		 * need to bring uptodate any buffers that are only partially
2005 		 * being written to.
2006 		 */
2007 		if (NInoNonResident(ni)) {
2008 			status = ntfs_prepare_pages_for_non_resident_write(
2009 					pages, do_pages, pos, bytes);
2010 			if (unlikely(status)) {
2011 				loff_t i_size;
2012 
2013 				do {
2014 					unlock_page(pages[--do_pages]);
2015 					page_cache_release(pages[do_pages]);
2016 				} while (do_pages);
2017 				/*
2018 				 * The write preparation may have instantiated
2019 				 * allocated space outside i_size.  Trim this
2020 				 * off again.  We can ignore any errors in this
2021 				 * case as we will just be waisting a bit of
2022 				 * allocated space, which is not a disaster.
2023 				 */
2024 				i_size = i_size_read(vi);
2025 				if (pos + bytes > i_size)
2026 					vmtruncate(vi, i_size);
2027 				break;
2028 			}
2029 		}
2030 		u = (pos >> PAGE_CACHE_SHIFT) - pages[0]->index;
2031 		if (likely(nr_segs == 1)) {
2032 			copied = ntfs_copy_from_user(pages + u, do_pages - u,
2033 					ofs, buf, bytes);
2034 			buf += copied;
2035 		} else
2036 			copied = ntfs_copy_from_user_iovec(pages + u,
2037 					do_pages - u, ofs, &iov, &iov_ofs,
2038 					bytes);
2039 		ntfs_flush_dcache_pages(pages + u, do_pages - u);
2040 		status = ntfs_commit_pages_after_write(pages, do_pages, pos,
2041 				bytes);
2042 		if (likely(!status)) {
2043 			written += copied;
2044 			count -= copied;
2045 			pos += copied;
2046 			if (unlikely(copied != bytes))
2047 				status = -EFAULT;
2048 		}
2049 		do {
2050 			unlock_page(pages[--do_pages]);
2051 			mark_page_accessed(pages[do_pages]);
2052 			page_cache_release(pages[do_pages]);
2053 		} while (do_pages);
2054 		if (unlikely(status))
2055 			break;
2056 		balance_dirty_pages_ratelimited(mapping);
2057 		cond_resched();
2058 	} while (count);
2059 err_out:
2060 	*ppos = pos;
2061 	if (cached_page)
2062 		page_cache_release(cached_page);
2063 	ntfs_debug("Done.  Returning %s (written 0x%lx, status %li).",
2064 			written ? "written" : "status", (unsigned long)written,
2065 			(long)status);
2066 	return written ? written : status;
2067 }
2068 
2069 /**
2070  * ntfs_file_aio_write_nolock -
2071  */
ntfs_file_aio_write_nolock(struct kiocb * iocb,const struct iovec * iov,unsigned long nr_segs,loff_t * ppos)2072 static ssize_t ntfs_file_aio_write_nolock(struct kiocb *iocb,
2073 		const struct iovec *iov, unsigned long nr_segs, loff_t *ppos)
2074 {
2075 	struct file *file = iocb->ki_filp;
2076 	struct address_space *mapping = file->f_mapping;
2077 	struct inode *inode = mapping->host;
2078 	loff_t pos;
2079 	size_t count;		/* after file limit checks */
2080 	ssize_t written, err;
2081 
2082 	count = 0;
2083 	err = generic_segment_checks(iov, &nr_segs, &count, VERIFY_READ);
2084 	if (err)
2085 		return err;
2086 	pos = *ppos;
2087 	vfs_check_frozen(inode->i_sb, SB_FREEZE_WRITE);
2088 	/* We can write back this queue in page reclaim. */
2089 	current->backing_dev_info = mapping->backing_dev_info;
2090 	written = 0;
2091 	err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode));
2092 	if (err)
2093 		goto out;
2094 	if (!count)
2095 		goto out;
2096 	err = file_remove_suid(file);
2097 	if (err)
2098 		goto out;
2099 	err = file_update_time(file);
2100 	if (err)
2101 		goto out;
2102 	written = ntfs_file_buffered_write(iocb, iov, nr_segs, pos, ppos,
2103 			count);
2104 out:
2105 	current->backing_dev_info = NULL;
2106 	return written ? written : err;
2107 }
2108 
2109 /**
2110  * ntfs_file_aio_write -
2111  */
ntfs_file_aio_write(struct kiocb * iocb,const struct iovec * iov,unsigned long nr_segs,loff_t pos)2112 static ssize_t ntfs_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
2113 		unsigned long nr_segs, loff_t pos)
2114 {
2115 	struct file *file = iocb->ki_filp;
2116 	struct address_space *mapping = file->f_mapping;
2117 	struct inode *inode = mapping->host;
2118 	ssize_t ret;
2119 
2120 	BUG_ON(iocb->ki_pos != pos);
2121 
2122 	mutex_lock(&inode->i_mutex);
2123 	ret = ntfs_file_aio_write_nolock(iocb, iov, nr_segs, &iocb->ki_pos);
2124 	mutex_unlock(&inode->i_mutex);
2125 	if (ret > 0) {
2126 		int err = generic_write_sync(file, pos, ret);
2127 		if (err < 0)
2128 			ret = err;
2129 	}
2130 	return ret;
2131 }
2132 
2133 /**
2134  * ntfs_file_fsync - sync a file to disk
2135  * @filp:	file to be synced
2136  * @datasync:	if non-zero only flush user data and not metadata
2137  *
2138  * Data integrity sync of a file to disk.  Used for fsync, fdatasync, and msync
2139  * system calls.  This function is inspired by fs/buffer.c::file_fsync().
2140  *
2141  * If @datasync is false, write the mft record and all associated extent mft
2142  * records as well as the $DATA attribute and then sync the block device.
2143  *
2144  * If @datasync is true and the attribute is non-resident, we skip the writing
2145  * of the mft record and all associated extent mft records (this might still
2146  * happen due to the write_inode_now() call).
2147  *
2148  * Also, if @datasync is true, we do not wait on the inode to be written out
2149  * but we always wait on the page cache pages to be written out.
2150  *
2151  * Locking: Caller must hold i_mutex on the inode.
2152  *
2153  * TODO: We should probably also write all attribute/index inodes associated
2154  * with this inode but since we have no simple way of getting to them we ignore
2155  * this problem for now.
2156  */
ntfs_file_fsync(struct file * filp,loff_t start,loff_t end,int datasync)2157 static int ntfs_file_fsync(struct file *filp, loff_t start, loff_t end,
2158 			   int datasync)
2159 {
2160 	struct inode *vi = filp->f_mapping->host;
2161 	int err, ret = 0;
2162 
2163 	ntfs_debug("Entering for inode 0x%lx.", vi->i_ino);
2164 
2165 	err = filemap_write_and_wait_range(vi->i_mapping, start, end);
2166 	if (err)
2167 		return err;
2168 	mutex_lock(&vi->i_mutex);
2169 
2170 	BUG_ON(S_ISDIR(vi->i_mode));
2171 	if (!datasync || !NInoNonResident(NTFS_I(vi)))
2172 		ret = __ntfs_write_inode(vi, 1);
2173 	write_inode_now(vi, !datasync);
2174 	/*
2175 	 * NOTE: If we were to use mapping->private_list (see ext2 and
2176 	 * fs/buffer.c) for dirty blocks then we could optimize the below to be
2177 	 * sync_mapping_buffers(vi->i_mapping).
2178 	 */
2179 	err = sync_blockdev(vi->i_sb->s_bdev);
2180 	if (unlikely(err && !ret))
2181 		ret = err;
2182 	if (likely(!ret))
2183 		ntfs_debug("Done.");
2184 	else
2185 		ntfs_warning(vi->i_sb, "Failed to f%ssync inode 0x%lx.  Error "
2186 				"%u.", datasync ? "data" : "", vi->i_ino, -ret);
2187 	mutex_unlock(&vi->i_mutex);
2188 	return ret;
2189 }
2190 
2191 #endif /* NTFS_RW */
2192 
2193 const struct file_operations ntfs_file_ops = {
2194 	.llseek		= generic_file_llseek,	 /* Seek inside file. */
2195 	.read		= do_sync_read,		 /* Read from file. */
2196 	.aio_read	= generic_file_aio_read, /* Async read from file. */
2197 #ifdef NTFS_RW
2198 	.write		= do_sync_write,	 /* Write to file. */
2199 	.aio_write	= ntfs_file_aio_write,	 /* Async write to file. */
2200 	/*.release	= ,*/			 /* Last file is closed.  See
2201 						    fs/ext2/file.c::
2202 						    ext2_release_file() for
2203 						    how to use this to discard
2204 						    preallocated space for
2205 						    write opened files. */
2206 	.fsync		= ntfs_file_fsync,	 /* Sync a file to disk. */
2207 	/*.aio_fsync	= ,*/			 /* Sync all outstanding async
2208 						    i/o operations on a
2209 						    kiocb. */
2210 #endif /* NTFS_RW */
2211 	/*.ioctl	= ,*/			 /* Perform function on the
2212 						    mounted filesystem. */
2213 	.mmap		= generic_file_mmap,	 /* Mmap file. */
2214 	.open		= ntfs_file_open,	 /* Open file. */
2215 	.splice_read	= generic_file_splice_read /* Zero-copy data send with
2216 						    the data source being on
2217 						    the ntfs partition.  We do
2218 						    not need to care about the
2219 						    data destination. */
2220 	/*.sendpage	= ,*/			 /* Zero-copy data send with
2221 						    the data destination being
2222 						    on the ntfs partition.  We
2223 						    do not need to care about
2224 						    the data source. */
2225 };
2226 
2227 const struct inode_operations ntfs_file_inode_ops = {
2228 #ifdef NTFS_RW
2229 	.truncate	= ntfs_truncate_vfs,
2230 	.setattr	= ntfs_setattr,
2231 #endif /* NTFS_RW */
2232 };
2233 
2234 const struct file_operations ntfs_empty_file_ops = {};
2235 
2236 const struct inode_operations ntfs_empty_inode_ops = {};
2237