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 */
  61static 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 */
 110static 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;
 183do_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);
 309done:
 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;
 319init_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);
 323err_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 */
 354static 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 */
 372static 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 */
 406static 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);
 437out:
 438	return err;
 439err_out:
 440	while (nr > 0) {
 441		unlock_page(pages[--nr]);
 442		page_cache_release(pages[nr]);
 443	}
 444	goto out;
 445}
 446
 447static 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 */
 480static 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;
 550do_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))) {
 618map_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);
 742retry_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		}
 833rl_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 */
1276static 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);
1308out:
1309	return total;
1310err_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
1325static 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
1354static 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 */
1392static 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);
1424out:
1425	return total;
1426err_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
1445static 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 */
1469static 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;
1576err_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 */
1624static 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;
1736err_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 */
1770static 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);
2059err_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 */
2072static 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);
2104out:
2105	current->backing_dev_info = NULL;
2106	return written ? written : err;
2107}
2108
2109/**
2110 * ntfs_file_aio_write -
2111 */
2112static 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 */
2157static 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
2193const 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
2227const 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
2234const struct file_operations ntfs_empty_file_ops = {};
2235
2236const struct inode_operations ntfs_empty_inode_ops = {};