1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /**
3  * mft.c - NTFS kernel mft record operations. Part of the Linux-NTFS project.
4  *
5  * Copyright (c) 2001-2012 Anton Altaparmakov and Tuxera Inc.
6  * Copyright (c) 2002 Richard Russon
7  */
8 
9 #include <linux/buffer_head.h>
10 #include <linux/slab.h>
11 #include <linux/swap.h>
12 #include <linux/bio.h>
13 
14 #include "attrib.h"
15 #include "aops.h"
16 #include "bitmap.h"
17 #include "debug.h"
18 #include "dir.h"
19 #include "lcnalloc.h"
20 #include "malloc.h"
21 #include "mft.h"
22 #include "ntfs.h"
23 
24 #define MAX_BHS	(PAGE_SIZE / NTFS_BLOCK_SIZE)
25 
26 /**
27  * map_mft_record_page - map the page in which a specific mft record resides
28  * @ni:		ntfs inode whose mft record page to map
29  *
30  * This maps the page in which the mft record of the ntfs inode @ni is situated
31  * and returns a pointer to the mft record within the mapped page.
32  *
33  * Return value needs to be checked with IS_ERR() and if that is true PTR_ERR()
34  * contains the negative error code returned.
35  */
map_mft_record_page(ntfs_inode * ni)36 static inline MFT_RECORD *map_mft_record_page(ntfs_inode *ni)
37 {
38 	loff_t i_size;
39 	ntfs_volume *vol = ni->vol;
40 	struct inode *mft_vi = vol->mft_ino;
41 	struct page *page;
42 	unsigned long index, end_index;
43 	unsigned ofs;
44 
45 	BUG_ON(ni->page);
46 	/*
47 	 * The index into the page cache and the offset within the page cache
48 	 * page of the wanted mft record. FIXME: We need to check for
49 	 * overflowing the unsigned long, but I don't think we would ever get
50 	 * here if the volume was that big...
51 	 */
52 	index = (u64)ni->mft_no << vol->mft_record_size_bits >>
53 			PAGE_SHIFT;
54 	ofs = (ni->mft_no << vol->mft_record_size_bits) & ~PAGE_MASK;
55 
56 	i_size = i_size_read(mft_vi);
57 	/* The maximum valid index into the page cache for $MFT's data. */
58 	end_index = i_size >> PAGE_SHIFT;
59 
60 	/* If the wanted index is out of bounds the mft record doesn't exist. */
61 	if (unlikely(index >= end_index)) {
62 		if (index > end_index || (i_size & ~PAGE_MASK) < ofs +
63 				vol->mft_record_size) {
64 			page = ERR_PTR(-ENOENT);
65 			ntfs_error(vol->sb, "Attempt to read mft record 0x%lx, "
66 					"which is beyond the end of the mft.  "
67 					"This is probably a bug in the ntfs "
68 					"driver.", ni->mft_no);
69 			goto err_out;
70 		}
71 	}
72 	/* Read, map, and pin the page. */
73 	page = ntfs_map_page(mft_vi->i_mapping, index);
74 	if (!IS_ERR(page)) {
75 		/* Catch multi sector transfer fixup errors. */
76 		if (likely(ntfs_is_mft_recordp((le32*)(page_address(page) +
77 				ofs)))) {
78 			ni->page = page;
79 			ni->page_ofs = ofs;
80 			return page_address(page) + ofs;
81 		}
82 		ntfs_error(vol->sb, "Mft record 0x%lx is corrupt.  "
83 				"Run chkdsk.", ni->mft_no);
84 		ntfs_unmap_page(page);
85 		page = ERR_PTR(-EIO);
86 		NVolSetErrors(vol);
87 	}
88 err_out:
89 	ni->page = NULL;
90 	ni->page_ofs = 0;
91 	return (void*)page;
92 }
93 
94 /**
95  * map_mft_record - map, pin and lock an mft record
96  * @ni:		ntfs inode whose MFT record to map
97  *
98  * First, take the mrec_lock mutex.  We might now be sleeping, while waiting
99  * for the mutex if it was already locked by someone else.
100  *
101  * The page of the record is mapped using map_mft_record_page() before being
102  * returned to the caller.
103  *
104  * This in turn uses ntfs_map_page() to get the page containing the wanted mft
105  * record (it in turn calls read_cache_page() which reads it in from disk if
106  * necessary, increments the use count on the page so that it cannot disappear
107  * under us and returns a reference to the page cache page).
108  *
109  * If read_cache_page() invokes ntfs_readpage() to load the page from disk, it
110  * sets PG_locked and clears PG_uptodate on the page. Once I/O has completed
111  * and the post-read mst fixups on each mft record in the page have been
112  * performed, the page gets PG_uptodate set and PG_locked cleared (this is done
113  * in our asynchronous I/O completion handler end_buffer_read_mft_async()).
114  * ntfs_map_page() waits for PG_locked to become clear and checks if
115  * PG_uptodate is set and returns an error code if not. This provides
116  * sufficient protection against races when reading/using the page.
117  *
118  * However there is the write mapping to think about. Doing the above described
119  * checking here will be fine, because when initiating the write we will set
120  * PG_locked and clear PG_uptodate making sure nobody is touching the page
121  * contents. Doing the locking this way means that the commit to disk code in
122  * the page cache code paths is automatically sufficiently locked with us as
123  * we will not touch a page that has been locked or is not uptodate. The only
124  * locking problem then is them locking the page while we are accessing it.
125  *
126  * So that code will end up having to own the mrec_lock of all mft
127  * records/inodes present in the page before I/O can proceed. In that case we
128  * wouldn't need to bother with PG_locked and PG_uptodate as nobody will be
129  * accessing anything without owning the mrec_lock mutex.  But we do need to
130  * use them because of the read_cache_page() invocation and the code becomes so
131  * much simpler this way that it is well worth it.
132  *
133  * The mft record is now ours and we return a pointer to it. You need to check
134  * the returned pointer with IS_ERR() and if that is true, PTR_ERR() will return
135  * the error code.
136  *
137  * NOTE: Caller is responsible for setting the mft record dirty before calling
138  * unmap_mft_record(). This is obviously only necessary if the caller really
139  * modified the mft record...
140  * Q: Do we want to recycle one of the VFS inode state bits instead?
141  * A: No, the inode ones mean we want to change the mft record, not we want to
142  * write it out.
143  */
map_mft_record(ntfs_inode * ni)144 MFT_RECORD *map_mft_record(ntfs_inode *ni)
145 {
146 	MFT_RECORD *m;
147 
148 	ntfs_debug("Entering for mft_no 0x%lx.", ni->mft_no);
149 
150 	/* Make sure the ntfs inode doesn't go away. */
151 	atomic_inc(&ni->count);
152 
153 	/* Serialize access to this mft record. */
154 	mutex_lock(&ni->mrec_lock);
155 
156 	m = map_mft_record_page(ni);
157 	if (!IS_ERR(m))
158 		return m;
159 
160 	mutex_unlock(&ni->mrec_lock);
161 	atomic_dec(&ni->count);
162 	ntfs_error(ni->vol->sb, "Failed with error code %lu.", -PTR_ERR(m));
163 	return m;
164 }
165 
166 /**
167  * unmap_mft_record_page - unmap the page in which a specific mft record resides
168  * @ni:		ntfs inode whose mft record page to unmap
169  *
170  * This unmaps the page in which the mft record of the ntfs inode @ni is
171  * situated and returns. This is a NOOP if highmem is not configured.
172  *
173  * The unmap happens via ntfs_unmap_page() which in turn decrements the use
174  * count on the page thus releasing it from the pinned state.
175  *
176  * We do not actually unmap the page from memory of course, as that will be
177  * done by the page cache code itself when memory pressure increases or
178  * whatever.
179  */
unmap_mft_record_page(ntfs_inode * ni)180 static inline void unmap_mft_record_page(ntfs_inode *ni)
181 {
182 	BUG_ON(!ni->page);
183 
184 	// TODO: If dirty, blah...
185 	ntfs_unmap_page(ni->page);
186 	ni->page = NULL;
187 	ni->page_ofs = 0;
188 	return;
189 }
190 
191 /**
192  * unmap_mft_record - release a mapped mft record
193  * @ni:		ntfs inode whose MFT record to unmap
194  *
195  * We release the page mapping and the mrec_lock mutex which unmaps the mft
196  * record and releases it for others to get hold of. We also release the ntfs
197  * inode by decrementing the ntfs inode reference count.
198  *
199  * NOTE: If caller has modified the mft record, it is imperative to set the mft
200  * record dirty BEFORE calling unmap_mft_record().
201  */
unmap_mft_record(ntfs_inode * ni)202 void unmap_mft_record(ntfs_inode *ni)
203 {
204 	struct page *page = ni->page;
205 
206 	BUG_ON(!page);
207 
208 	ntfs_debug("Entering for mft_no 0x%lx.", ni->mft_no);
209 
210 	unmap_mft_record_page(ni);
211 	mutex_unlock(&ni->mrec_lock);
212 	atomic_dec(&ni->count);
213 	/*
214 	 * If pure ntfs_inode, i.e. no vfs inode attached, we leave it to
215 	 * ntfs_clear_extent_inode() in the extent inode case, and to the
216 	 * caller in the non-extent, yet pure ntfs inode case, to do the actual
217 	 * tear down of all structures and freeing of all allocated memory.
218 	 */
219 	return;
220 }
221 
222 /**
223  * map_extent_mft_record - load an extent inode and attach it to its base
224  * @base_ni:	base ntfs inode
225  * @mref:	mft reference of the extent inode to load
226  * @ntfs_ino:	on successful return, pointer to the ntfs_inode structure
227  *
228  * Load the extent mft record @mref and attach it to its base inode @base_ni.
229  * Return the mapped extent mft record if IS_ERR(result) is false.  Otherwise
230  * PTR_ERR(result) gives the negative error code.
231  *
232  * On successful return, @ntfs_ino contains a pointer to the ntfs_inode
233  * structure of the mapped extent inode.
234  */
map_extent_mft_record(ntfs_inode * base_ni,MFT_REF mref,ntfs_inode ** ntfs_ino)235 MFT_RECORD *map_extent_mft_record(ntfs_inode *base_ni, MFT_REF mref,
236 		ntfs_inode **ntfs_ino)
237 {
238 	MFT_RECORD *m;
239 	ntfs_inode *ni = NULL;
240 	ntfs_inode **extent_nis = NULL;
241 	int i;
242 	unsigned long mft_no = MREF(mref);
243 	u16 seq_no = MSEQNO(mref);
244 	bool destroy_ni = false;
245 
246 	ntfs_debug("Mapping extent mft record 0x%lx (base mft record 0x%lx).",
247 			mft_no, base_ni->mft_no);
248 	/* Make sure the base ntfs inode doesn't go away. */
249 	atomic_inc(&base_ni->count);
250 	/*
251 	 * Check if this extent inode has already been added to the base inode,
252 	 * in which case just return it. If not found, add it to the base
253 	 * inode before returning it.
254 	 */
255 	mutex_lock(&base_ni->extent_lock);
256 	if (base_ni->nr_extents > 0) {
257 		extent_nis = base_ni->ext.extent_ntfs_inos;
258 		for (i = 0; i < base_ni->nr_extents; i++) {
259 			if (mft_no != extent_nis[i]->mft_no)
260 				continue;
261 			ni = extent_nis[i];
262 			/* Make sure the ntfs inode doesn't go away. */
263 			atomic_inc(&ni->count);
264 			break;
265 		}
266 	}
267 	if (likely(ni != NULL)) {
268 		mutex_unlock(&base_ni->extent_lock);
269 		atomic_dec(&base_ni->count);
270 		/* We found the record; just have to map and return it. */
271 		m = map_mft_record(ni);
272 		/* map_mft_record() has incremented this on success. */
273 		atomic_dec(&ni->count);
274 		if (!IS_ERR(m)) {
275 			/* Verify the sequence number. */
276 			if (likely(le16_to_cpu(m->sequence_number) == seq_no)) {
277 				ntfs_debug("Done 1.");
278 				*ntfs_ino = ni;
279 				return m;
280 			}
281 			unmap_mft_record(ni);
282 			ntfs_error(base_ni->vol->sb, "Found stale extent mft "
283 					"reference! Corrupt filesystem. "
284 					"Run chkdsk.");
285 			return ERR_PTR(-EIO);
286 		}
287 map_err_out:
288 		ntfs_error(base_ni->vol->sb, "Failed to map extent "
289 				"mft record, error code %ld.", -PTR_ERR(m));
290 		return m;
291 	}
292 	/* Record wasn't there. Get a new ntfs inode and initialize it. */
293 	ni = ntfs_new_extent_inode(base_ni->vol->sb, mft_no);
294 	if (unlikely(!ni)) {
295 		mutex_unlock(&base_ni->extent_lock);
296 		atomic_dec(&base_ni->count);
297 		return ERR_PTR(-ENOMEM);
298 	}
299 	ni->vol = base_ni->vol;
300 	ni->seq_no = seq_no;
301 	ni->nr_extents = -1;
302 	ni->ext.base_ntfs_ino = base_ni;
303 	/* Now map the record. */
304 	m = map_mft_record(ni);
305 	if (IS_ERR(m)) {
306 		mutex_unlock(&base_ni->extent_lock);
307 		atomic_dec(&base_ni->count);
308 		ntfs_clear_extent_inode(ni);
309 		goto map_err_out;
310 	}
311 	/* Verify the sequence number if it is present. */
312 	if (seq_no && (le16_to_cpu(m->sequence_number) != seq_no)) {
313 		ntfs_error(base_ni->vol->sb, "Found stale extent mft "
314 				"reference! Corrupt filesystem. Run chkdsk.");
315 		destroy_ni = true;
316 		m = ERR_PTR(-EIO);
317 		goto unm_err_out;
318 	}
319 	/* Attach extent inode to base inode, reallocating memory if needed. */
320 	if (!(base_ni->nr_extents & 3)) {
321 		ntfs_inode **tmp;
322 		int new_size = (base_ni->nr_extents + 4) * sizeof(ntfs_inode *);
323 
324 		tmp = kmalloc(new_size, GFP_NOFS);
325 		if (unlikely(!tmp)) {
326 			ntfs_error(base_ni->vol->sb, "Failed to allocate "
327 					"internal buffer.");
328 			destroy_ni = true;
329 			m = ERR_PTR(-ENOMEM);
330 			goto unm_err_out;
331 		}
332 		if (base_ni->nr_extents) {
333 			BUG_ON(!base_ni->ext.extent_ntfs_inos);
334 			memcpy(tmp, base_ni->ext.extent_ntfs_inos, new_size -
335 					4 * sizeof(ntfs_inode *));
336 			kfree(base_ni->ext.extent_ntfs_inos);
337 		}
338 		base_ni->ext.extent_ntfs_inos = tmp;
339 	}
340 	base_ni->ext.extent_ntfs_inos[base_ni->nr_extents++] = ni;
341 	mutex_unlock(&base_ni->extent_lock);
342 	atomic_dec(&base_ni->count);
343 	ntfs_debug("Done 2.");
344 	*ntfs_ino = ni;
345 	return m;
346 unm_err_out:
347 	unmap_mft_record(ni);
348 	mutex_unlock(&base_ni->extent_lock);
349 	atomic_dec(&base_ni->count);
350 	/*
351 	 * If the extent inode was not attached to the base inode we need to
352 	 * release it or we will leak memory.
353 	 */
354 	if (destroy_ni)
355 		ntfs_clear_extent_inode(ni);
356 	return m;
357 }
358 
359 #ifdef NTFS_RW
360 
361 /**
362  * __mark_mft_record_dirty - set the mft record and the page containing it dirty
363  * @ni:		ntfs inode describing the mapped mft record
364  *
365  * Internal function.  Users should call mark_mft_record_dirty() instead.
366  *
367  * Set the mapped (extent) mft record of the (base or extent) ntfs inode @ni,
368  * as well as the page containing the mft record, dirty.  Also, mark the base
369  * vfs inode dirty.  This ensures that any changes to the mft record are
370  * written out to disk.
371  *
372  * NOTE:  We only set I_DIRTY_DATASYNC (and not I_DIRTY_PAGES)
373  * on the base vfs inode, because even though file data may have been modified,
374  * it is dirty in the inode meta data rather than the data page cache of the
375  * inode, and thus there are no data pages that need writing out.  Therefore, a
376  * full mark_inode_dirty() is overkill.  A mark_inode_dirty_sync(), on the
377  * other hand, is not sufficient, because ->write_inode needs to be called even
378  * in case of fdatasync. This needs to happen or the file data would not
379  * necessarily hit the device synchronously, even though the vfs inode has the
380  * O_SYNC flag set.  Also, I_DIRTY_DATASYNC simply "feels" better than just
381  * I_DIRTY_SYNC, since the file data has not actually hit the block device yet,
382  * which is not what I_DIRTY_SYNC on its own would suggest.
383  */
__mark_mft_record_dirty(ntfs_inode * ni)384 void __mark_mft_record_dirty(ntfs_inode *ni)
385 {
386 	ntfs_inode *base_ni;
387 
388 	ntfs_debug("Entering for inode 0x%lx.", ni->mft_no);
389 	BUG_ON(NInoAttr(ni));
390 	mark_ntfs_record_dirty(ni->page, ni->page_ofs);
391 	/* Determine the base vfs inode and mark it dirty, too. */
392 	mutex_lock(&ni->extent_lock);
393 	if (likely(ni->nr_extents >= 0))
394 		base_ni = ni;
395 	else
396 		base_ni = ni->ext.base_ntfs_ino;
397 	mutex_unlock(&ni->extent_lock);
398 	__mark_inode_dirty(VFS_I(base_ni), I_DIRTY_DATASYNC);
399 }
400 
401 static const char *ntfs_please_email = "Please email "
402 		"linux-ntfs-dev@lists.sourceforge.net and say that you saw "
403 		"this message.  Thank you.";
404 
405 /**
406  * ntfs_sync_mft_mirror_umount - synchronise an mft record to the mft mirror
407  * @vol:	ntfs volume on which the mft record to synchronize resides
408  * @mft_no:	mft record number of mft record to synchronize
409  * @m:		mapped, mst protected (extent) mft record to synchronize
410  *
411  * Write the mapped, mst protected (extent) mft record @m with mft record
412  * number @mft_no to the mft mirror ($MFTMirr) of the ntfs volume @vol,
413  * bypassing the page cache and the $MFTMirr inode itself.
414  *
415  * This function is only for use at umount time when the mft mirror inode has
416  * already been disposed off.  We BUG() if we are called while the mft mirror
417  * inode is still attached to the volume.
418  *
419  * On success return 0.  On error return -errno.
420  *
421  * NOTE:  This function is not implemented yet as I am not convinced it can
422  * actually be triggered considering the sequence of commits we do in super.c::
423  * ntfs_put_super().  But just in case we provide this place holder as the
424  * alternative would be either to BUG() or to get a NULL pointer dereference
425  * and Oops.
426  */
ntfs_sync_mft_mirror_umount(ntfs_volume * vol,const unsigned long mft_no,MFT_RECORD * m)427 static int ntfs_sync_mft_mirror_umount(ntfs_volume *vol,
428 		const unsigned long mft_no, MFT_RECORD *m)
429 {
430 	BUG_ON(vol->mftmirr_ino);
431 	ntfs_error(vol->sb, "Umount time mft mirror syncing is not "
432 			"implemented yet.  %s", ntfs_please_email);
433 	return -EOPNOTSUPP;
434 }
435 
436 /**
437  * ntfs_sync_mft_mirror - synchronize an mft record to the mft mirror
438  * @vol:	ntfs volume on which the mft record to synchronize resides
439  * @mft_no:	mft record number of mft record to synchronize
440  * @m:		mapped, mst protected (extent) mft record to synchronize
441  * @sync:	if true, wait for i/o completion
442  *
443  * Write the mapped, mst protected (extent) mft record @m with mft record
444  * number @mft_no to the mft mirror ($MFTMirr) of the ntfs volume @vol.
445  *
446  * On success return 0.  On error return -errno and set the volume errors flag
447  * in the ntfs volume @vol.
448  *
449  * NOTE:  We always perform synchronous i/o and ignore the @sync parameter.
450  *
451  * TODO:  If @sync is false, want to do truly asynchronous i/o, i.e. just
452  * schedule i/o via ->writepage or do it via kntfsd or whatever.
453  */
ntfs_sync_mft_mirror(ntfs_volume * vol,const unsigned long mft_no,MFT_RECORD * m,int sync)454 int ntfs_sync_mft_mirror(ntfs_volume *vol, const unsigned long mft_no,
455 		MFT_RECORD *m, int sync)
456 {
457 	struct page *page;
458 	unsigned int blocksize = vol->sb->s_blocksize;
459 	int max_bhs = vol->mft_record_size / blocksize;
460 	struct buffer_head *bhs[MAX_BHS];
461 	struct buffer_head *bh, *head;
462 	u8 *kmirr;
463 	runlist_element *rl;
464 	unsigned int block_start, block_end, m_start, m_end, page_ofs;
465 	int i_bhs, nr_bhs, err = 0;
466 	unsigned char blocksize_bits = vol->sb->s_blocksize_bits;
467 
468 	ntfs_debug("Entering for inode 0x%lx.", mft_no);
469 	BUG_ON(!max_bhs);
470 	if (WARN_ON(max_bhs > MAX_BHS))
471 		return -EINVAL;
472 	if (unlikely(!vol->mftmirr_ino)) {
473 		/* This could happen during umount... */
474 		err = ntfs_sync_mft_mirror_umount(vol, mft_no, m);
475 		if (likely(!err))
476 			return err;
477 		goto err_out;
478 	}
479 	/* Get the page containing the mirror copy of the mft record @m. */
480 	page = ntfs_map_page(vol->mftmirr_ino->i_mapping, mft_no >>
481 			(PAGE_SHIFT - vol->mft_record_size_bits));
482 	if (IS_ERR(page)) {
483 		ntfs_error(vol->sb, "Failed to map mft mirror page.");
484 		err = PTR_ERR(page);
485 		goto err_out;
486 	}
487 	lock_page(page);
488 	BUG_ON(!PageUptodate(page));
489 	ClearPageUptodate(page);
490 	/* Offset of the mft mirror record inside the page. */
491 	page_ofs = (mft_no << vol->mft_record_size_bits) & ~PAGE_MASK;
492 	/* The address in the page of the mirror copy of the mft record @m. */
493 	kmirr = page_address(page) + page_ofs;
494 	/* Copy the mst protected mft record to the mirror. */
495 	memcpy(kmirr, m, vol->mft_record_size);
496 	/* Create uptodate buffers if not present. */
497 	if (unlikely(!page_has_buffers(page))) {
498 		struct buffer_head *tail;
499 
500 		bh = head = alloc_page_buffers(page, blocksize, true);
501 		do {
502 			set_buffer_uptodate(bh);
503 			tail = bh;
504 			bh = bh->b_this_page;
505 		} while (bh);
506 		tail->b_this_page = head;
507 		attach_page_private(page, head);
508 	}
509 	bh = head = page_buffers(page);
510 	BUG_ON(!bh);
511 	rl = NULL;
512 	nr_bhs = 0;
513 	block_start = 0;
514 	m_start = kmirr - (u8*)page_address(page);
515 	m_end = m_start + vol->mft_record_size;
516 	do {
517 		block_end = block_start + blocksize;
518 		/* If the buffer is outside the mft record, skip it. */
519 		if (block_end <= m_start)
520 			continue;
521 		if (unlikely(block_start >= m_end))
522 			break;
523 		/* Need to map the buffer if it is not mapped already. */
524 		if (unlikely(!buffer_mapped(bh))) {
525 			VCN vcn;
526 			LCN lcn;
527 			unsigned int vcn_ofs;
528 
529 			bh->b_bdev = vol->sb->s_bdev;
530 			/* Obtain the vcn and offset of the current block. */
531 			vcn = ((VCN)mft_no << vol->mft_record_size_bits) +
532 					(block_start - m_start);
533 			vcn_ofs = vcn & vol->cluster_size_mask;
534 			vcn >>= vol->cluster_size_bits;
535 			if (!rl) {
536 				down_read(&NTFS_I(vol->mftmirr_ino)->
537 						runlist.lock);
538 				rl = NTFS_I(vol->mftmirr_ino)->runlist.rl;
539 				/*
540 				 * $MFTMirr always has the whole of its runlist
541 				 * in memory.
542 				 */
543 				BUG_ON(!rl);
544 			}
545 			/* Seek to element containing target vcn. */
546 			while (rl->length && rl[1].vcn <= vcn)
547 				rl++;
548 			lcn = ntfs_rl_vcn_to_lcn(rl, vcn);
549 			/* For $MFTMirr, only lcn >= 0 is a successful remap. */
550 			if (likely(lcn >= 0)) {
551 				/* Setup buffer head to correct block. */
552 				bh->b_blocknr = ((lcn <<
553 						vol->cluster_size_bits) +
554 						vcn_ofs) >> blocksize_bits;
555 				set_buffer_mapped(bh);
556 			} else {
557 				bh->b_blocknr = -1;
558 				ntfs_error(vol->sb, "Cannot write mft mirror "
559 						"record 0x%lx because its "
560 						"location on disk could not "
561 						"be determined (error code "
562 						"%lli).", mft_no,
563 						(long long)lcn);
564 				err = -EIO;
565 			}
566 		}
567 		BUG_ON(!buffer_uptodate(bh));
568 		BUG_ON(!nr_bhs && (m_start != block_start));
569 		BUG_ON(nr_bhs >= max_bhs);
570 		bhs[nr_bhs++] = bh;
571 		BUG_ON((nr_bhs >= max_bhs) && (m_end != block_end));
572 	} while (block_start = block_end, (bh = bh->b_this_page) != head);
573 	if (unlikely(rl))
574 		up_read(&NTFS_I(vol->mftmirr_ino)->runlist.lock);
575 	if (likely(!err)) {
576 		/* Lock buffers and start synchronous write i/o on them. */
577 		for (i_bhs = 0; i_bhs < nr_bhs; i_bhs++) {
578 			struct buffer_head *tbh = bhs[i_bhs];
579 
580 			if (!trylock_buffer(tbh))
581 				BUG();
582 			BUG_ON(!buffer_uptodate(tbh));
583 			clear_buffer_dirty(tbh);
584 			get_bh(tbh);
585 			tbh->b_end_io = end_buffer_write_sync;
586 			submit_bh(REQ_OP_WRITE, 0, tbh);
587 		}
588 		/* Wait on i/o completion of buffers. */
589 		for (i_bhs = 0; i_bhs < nr_bhs; i_bhs++) {
590 			struct buffer_head *tbh = bhs[i_bhs];
591 
592 			wait_on_buffer(tbh);
593 			if (unlikely(!buffer_uptodate(tbh))) {
594 				err = -EIO;
595 				/*
596 				 * Set the buffer uptodate so the page and
597 				 * buffer states do not become out of sync.
598 				 */
599 				set_buffer_uptodate(tbh);
600 			}
601 		}
602 	} else /* if (unlikely(err)) */ {
603 		/* Clean the buffers. */
604 		for (i_bhs = 0; i_bhs < nr_bhs; i_bhs++)
605 			clear_buffer_dirty(bhs[i_bhs]);
606 	}
607 	/* Current state: all buffers are clean, unlocked, and uptodate. */
608 	/* Remove the mst protection fixups again. */
609 	post_write_mst_fixup((NTFS_RECORD*)kmirr);
610 	flush_dcache_page(page);
611 	SetPageUptodate(page);
612 	unlock_page(page);
613 	ntfs_unmap_page(page);
614 	if (likely(!err)) {
615 		ntfs_debug("Done.");
616 	} else {
617 		ntfs_error(vol->sb, "I/O error while writing mft mirror "
618 				"record 0x%lx!", mft_no);
619 err_out:
620 		ntfs_error(vol->sb, "Failed to synchronize $MFTMirr (error "
621 				"code %i).  Volume will be left marked dirty "
622 				"on umount.  Run ntfsfix on the partition "
623 				"after umounting to correct this.", -err);
624 		NVolSetErrors(vol);
625 	}
626 	return err;
627 }
628 
629 /**
630  * write_mft_record_nolock - write out a mapped (extent) mft record
631  * @ni:		ntfs inode describing the mapped (extent) mft record
632  * @m:		mapped (extent) mft record to write
633  * @sync:	if true, wait for i/o completion
634  *
635  * Write the mapped (extent) mft record @m described by the (regular or extent)
636  * ntfs inode @ni to backing store.  If the mft record @m has a counterpart in
637  * the mft mirror, that is also updated.
638  *
639  * We only write the mft record if the ntfs inode @ni is dirty and the first
640  * buffer belonging to its mft record is dirty, too.  We ignore the dirty state
641  * of subsequent buffers because we could have raced with
642  * fs/ntfs/aops.c::mark_ntfs_record_dirty().
643  *
644  * On success, clean the mft record and return 0.  On error, leave the mft
645  * record dirty and return -errno.
646  *
647  * NOTE:  We always perform synchronous i/o and ignore the @sync parameter.
648  * However, if the mft record has a counterpart in the mft mirror and @sync is
649  * true, we write the mft record, wait for i/o completion, and only then write
650  * the mft mirror copy.  This ensures that if the system crashes either the mft
651  * or the mft mirror will contain a self-consistent mft record @m.  If @sync is
652  * false on the other hand, we start i/o on both and then wait for completion
653  * on them.  This provides a speedup but no longer guarantees that you will end
654  * up with a self-consistent mft record in the case of a crash but if you asked
655  * for asynchronous writing you probably do not care about that anyway.
656  *
657  * TODO:  If @sync is false, want to do truly asynchronous i/o, i.e. just
658  * schedule i/o via ->writepage or do it via kntfsd or whatever.
659  */
write_mft_record_nolock(ntfs_inode * ni,MFT_RECORD * m,int sync)660 int write_mft_record_nolock(ntfs_inode *ni, MFT_RECORD *m, int sync)
661 {
662 	ntfs_volume *vol = ni->vol;
663 	struct page *page = ni->page;
664 	unsigned int blocksize = vol->sb->s_blocksize;
665 	unsigned char blocksize_bits = vol->sb->s_blocksize_bits;
666 	int max_bhs = vol->mft_record_size / blocksize;
667 	struct buffer_head *bhs[MAX_BHS];
668 	struct buffer_head *bh, *head;
669 	runlist_element *rl;
670 	unsigned int block_start, block_end, m_start, m_end;
671 	int i_bhs, nr_bhs, err = 0;
672 
673 	ntfs_debug("Entering for inode 0x%lx.", ni->mft_no);
674 	BUG_ON(NInoAttr(ni));
675 	BUG_ON(!max_bhs);
676 	BUG_ON(!PageLocked(page));
677 	if (WARN_ON(max_bhs > MAX_BHS)) {
678 		err = -EINVAL;
679 		goto err_out;
680 	}
681 	/*
682 	 * If the ntfs_inode is clean no need to do anything.  If it is dirty,
683 	 * mark it as clean now so that it can be redirtied later on if needed.
684 	 * There is no danger of races since the caller is holding the locks
685 	 * for the mft record @m and the page it is in.
686 	 */
687 	if (!NInoTestClearDirty(ni))
688 		goto done;
689 	bh = head = page_buffers(page);
690 	BUG_ON(!bh);
691 	rl = NULL;
692 	nr_bhs = 0;
693 	block_start = 0;
694 	m_start = ni->page_ofs;
695 	m_end = m_start + vol->mft_record_size;
696 	do {
697 		block_end = block_start + blocksize;
698 		/* If the buffer is outside the mft record, skip it. */
699 		if (block_end <= m_start)
700 			continue;
701 		if (unlikely(block_start >= m_end))
702 			break;
703 		/*
704 		 * If this block is not the first one in the record, we ignore
705 		 * the buffer's dirty state because we could have raced with a
706 		 * parallel mark_ntfs_record_dirty().
707 		 */
708 		if (block_start == m_start) {
709 			/* This block is the first one in the record. */
710 			if (!buffer_dirty(bh)) {
711 				BUG_ON(nr_bhs);
712 				/* Clean records are not written out. */
713 				break;
714 			}
715 		}
716 		/* Need to map the buffer if it is not mapped already. */
717 		if (unlikely(!buffer_mapped(bh))) {
718 			VCN vcn;
719 			LCN lcn;
720 			unsigned int vcn_ofs;
721 
722 			bh->b_bdev = vol->sb->s_bdev;
723 			/* Obtain the vcn and offset of the current block. */
724 			vcn = ((VCN)ni->mft_no << vol->mft_record_size_bits) +
725 					(block_start - m_start);
726 			vcn_ofs = vcn & vol->cluster_size_mask;
727 			vcn >>= vol->cluster_size_bits;
728 			if (!rl) {
729 				down_read(&NTFS_I(vol->mft_ino)->runlist.lock);
730 				rl = NTFS_I(vol->mft_ino)->runlist.rl;
731 				BUG_ON(!rl);
732 			}
733 			/* Seek to element containing target vcn. */
734 			while (rl->length && rl[1].vcn <= vcn)
735 				rl++;
736 			lcn = ntfs_rl_vcn_to_lcn(rl, vcn);
737 			/* For $MFT, only lcn >= 0 is a successful remap. */
738 			if (likely(lcn >= 0)) {
739 				/* Setup buffer head to correct block. */
740 				bh->b_blocknr = ((lcn <<
741 						vol->cluster_size_bits) +
742 						vcn_ofs) >> blocksize_bits;
743 				set_buffer_mapped(bh);
744 			} else {
745 				bh->b_blocknr = -1;
746 				ntfs_error(vol->sb, "Cannot write mft record "
747 						"0x%lx because its location "
748 						"on disk could not be "
749 						"determined (error code %lli).",
750 						ni->mft_no, (long long)lcn);
751 				err = -EIO;
752 			}
753 		}
754 		BUG_ON(!buffer_uptodate(bh));
755 		BUG_ON(!nr_bhs && (m_start != block_start));
756 		BUG_ON(nr_bhs >= max_bhs);
757 		bhs[nr_bhs++] = bh;
758 		BUG_ON((nr_bhs >= max_bhs) && (m_end != block_end));
759 	} while (block_start = block_end, (bh = bh->b_this_page) != head);
760 	if (unlikely(rl))
761 		up_read(&NTFS_I(vol->mft_ino)->runlist.lock);
762 	if (!nr_bhs)
763 		goto done;
764 	if (unlikely(err))
765 		goto cleanup_out;
766 	/* Apply the mst protection fixups. */
767 	err = pre_write_mst_fixup((NTFS_RECORD*)m, vol->mft_record_size);
768 	if (err) {
769 		ntfs_error(vol->sb, "Failed to apply mst fixups!");
770 		goto cleanup_out;
771 	}
772 	flush_dcache_mft_record_page(ni);
773 	/* Lock buffers and start synchronous write i/o on them. */
774 	for (i_bhs = 0; i_bhs < nr_bhs; i_bhs++) {
775 		struct buffer_head *tbh = bhs[i_bhs];
776 
777 		if (!trylock_buffer(tbh))
778 			BUG();
779 		BUG_ON(!buffer_uptodate(tbh));
780 		clear_buffer_dirty(tbh);
781 		get_bh(tbh);
782 		tbh->b_end_io = end_buffer_write_sync;
783 		submit_bh(REQ_OP_WRITE, 0, tbh);
784 	}
785 	/* Synchronize the mft mirror now if not @sync. */
786 	if (!sync && ni->mft_no < vol->mftmirr_size)
787 		ntfs_sync_mft_mirror(vol, ni->mft_no, m, sync);
788 	/* Wait on i/o completion of buffers. */
789 	for (i_bhs = 0; i_bhs < nr_bhs; i_bhs++) {
790 		struct buffer_head *tbh = bhs[i_bhs];
791 
792 		wait_on_buffer(tbh);
793 		if (unlikely(!buffer_uptodate(tbh))) {
794 			err = -EIO;
795 			/*
796 			 * Set the buffer uptodate so the page and buffer
797 			 * states do not become out of sync.
798 			 */
799 			if (PageUptodate(page))
800 				set_buffer_uptodate(tbh);
801 		}
802 	}
803 	/* If @sync, now synchronize the mft mirror. */
804 	if (sync && ni->mft_no < vol->mftmirr_size)
805 		ntfs_sync_mft_mirror(vol, ni->mft_no, m, sync);
806 	/* Remove the mst protection fixups again. */
807 	post_write_mst_fixup((NTFS_RECORD*)m);
808 	flush_dcache_mft_record_page(ni);
809 	if (unlikely(err)) {
810 		/* I/O error during writing.  This is really bad! */
811 		ntfs_error(vol->sb, "I/O error while writing mft record "
812 				"0x%lx!  Marking base inode as bad.  You "
813 				"should unmount the volume and run chkdsk.",
814 				ni->mft_no);
815 		goto err_out;
816 	}
817 done:
818 	ntfs_debug("Done.");
819 	return 0;
820 cleanup_out:
821 	/* Clean the buffers. */
822 	for (i_bhs = 0; i_bhs < nr_bhs; i_bhs++)
823 		clear_buffer_dirty(bhs[i_bhs]);
824 err_out:
825 	/*
826 	 * Current state: all buffers are clean, unlocked, and uptodate.
827 	 * The caller should mark the base inode as bad so that no more i/o
828 	 * happens.  ->clear_inode() will still be invoked so all extent inodes
829 	 * and other allocated memory will be freed.
830 	 */
831 	if (err == -ENOMEM) {
832 		ntfs_error(vol->sb, "Not enough memory to write mft record.  "
833 				"Redirtying so the write is retried later.");
834 		mark_mft_record_dirty(ni);
835 		err = 0;
836 	} else
837 		NVolSetErrors(vol);
838 	return err;
839 }
840 
841 /**
842  * ntfs_may_write_mft_record - check if an mft record may be written out
843  * @vol:	[IN]  ntfs volume on which the mft record to check resides
844  * @mft_no:	[IN]  mft record number of the mft record to check
845  * @m:		[IN]  mapped mft record to check
846  * @locked_ni:	[OUT] caller has to unlock this ntfs inode if one is returned
847  *
848  * Check if the mapped (base or extent) mft record @m with mft record number
849  * @mft_no belonging to the ntfs volume @vol may be written out.  If necessary
850  * and possible the ntfs inode of the mft record is locked and the base vfs
851  * inode is pinned.  The locked ntfs inode is then returned in @locked_ni.  The
852  * caller is responsible for unlocking the ntfs inode and unpinning the base
853  * vfs inode.
854  *
855  * Return 'true' if the mft record may be written out and 'false' if not.
856  *
857  * The caller has locked the page and cleared the uptodate flag on it which
858  * means that we can safely write out any dirty mft records that do not have
859  * their inodes in icache as determined by ilookup5() as anyone
860  * opening/creating such an inode would block when attempting to map the mft
861  * record in read_cache_page() until we are finished with the write out.
862  *
863  * Here is a description of the tests we perform:
864  *
865  * If the inode is found in icache we know the mft record must be a base mft
866  * record.  If it is dirty, we do not write it and return 'false' as the vfs
867  * inode write paths will result in the access times being updated which would
868  * cause the base mft record to be redirtied and written out again.  (We know
869  * the access time update will modify the base mft record because Windows
870  * chkdsk complains if the standard information attribute is not in the base
871  * mft record.)
872  *
873  * If the inode is in icache and not dirty, we attempt to lock the mft record
874  * and if we find the lock was already taken, it is not safe to write the mft
875  * record and we return 'false'.
876  *
877  * If we manage to obtain the lock we have exclusive access to the mft record,
878  * which also allows us safe writeout of the mft record.  We then set
879  * @locked_ni to the locked ntfs inode and return 'true'.
880  *
881  * Note we cannot just lock the mft record and sleep while waiting for the lock
882  * because this would deadlock due to lock reversal (normally the mft record is
883  * locked before the page is locked but we already have the page locked here
884  * when we try to lock the mft record).
885  *
886  * If the inode is not in icache we need to perform further checks.
887  *
888  * If the mft record is not a FILE record or it is a base mft record, we can
889  * safely write it and return 'true'.
890  *
891  * We now know the mft record is an extent mft record.  We check if the inode
892  * corresponding to its base mft record is in icache and obtain a reference to
893  * it if it is.  If it is not, we can safely write it and return 'true'.
894  *
895  * We now have the base inode for the extent mft record.  We check if it has an
896  * ntfs inode for the extent mft record attached and if not it is safe to write
897  * the extent mft record and we return 'true'.
898  *
899  * The ntfs inode for the extent mft record is attached to the base inode so we
900  * attempt to lock the extent mft record and if we find the lock was already
901  * taken, it is not safe to write the extent mft record and we return 'false'.
902  *
903  * If we manage to obtain the lock we have exclusive access to the extent mft
904  * record, which also allows us safe writeout of the extent mft record.  We
905  * set the ntfs inode of the extent mft record clean and then set @locked_ni to
906  * the now locked ntfs inode and return 'true'.
907  *
908  * Note, the reason for actually writing dirty mft records here and not just
909  * relying on the vfs inode dirty code paths is that we can have mft records
910  * modified without them ever having actual inodes in memory.  Also we can have
911  * dirty mft records with clean ntfs inodes in memory.  None of the described
912  * cases would result in the dirty mft records being written out if we only
913  * relied on the vfs inode dirty code paths.  And these cases can really occur
914  * during allocation of new mft records and in particular when the
915  * initialized_size of the $MFT/$DATA attribute is extended and the new space
916  * is initialized using ntfs_mft_record_format().  The clean inode can then
917  * appear if the mft record is reused for a new inode before it got written
918  * out.
919  */
ntfs_may_write_mft_record(ntfs_volume * vol,const unsigned long mft_no,const MFT_RECORD * m,ntfs_inode ** locked_ni)920 bool ntfs_may_write_mft_record(ntfs_volume *vol, const unsigned long mft_no,
921 		const MFT_RECORD *m, ntfs_inode **locked_ni)
922 {
923 	struct super_block *sb = vol->sb;
924 	struct inode *mft_vi = vol->mft_ino;
925 	struct inode *vi;
926 	ntfs_inode *ni, *eni, **extent_nis;
927 	int i;
928 	ntfs_attr na;
929 
930 	ntfs_debug("Entering for inode 0x%lx.", mft_no);
931 	/*
932 	 * Normally we do not return a locked inode so set @locked_ni to NULL.
933 	 */
934 	BUG_ON(!locked_ni);
935 	*locked_ni = NULL;
936 	/*
937 	 * Check if the inode corresponding to this mft record is in the VFS
938 	 * inode cache and obtain a reference to it if it is.
939 	 */
940 	ntfs_debug("Looking for inode 0x%lx in icache.", mft_no);
941 	na.mft_no = mft_no;
942 	na.name = NULL;
943 	na.name_len = 0;
944 	na.type = AT_UNUSED;
945 	/*
946 	 * Optimize inode 0, i.e. $MFT itself, since we have it in memory and
947 	 * we get here for it rather often.
948 	 */
949 	if (!mft_no) {
950 		/* Balance the below iput(). */
951 		vi = igrab(mft_vi);
952 		BUG_ON(vi != mft_vi);
953 	} else {
954 		/*
955 		 * Have to use ilookup5_nowait() since ilookup5() waits for the
956 		 * inode lock which causes ntfs to deadlock when a concurrent
957 		 * inode write via the inode dirty code paths and the page
958 		 * dirty code path of the inode dirty code path when writing
959 		 * $MFT occurs.
960 		 */
961 		vi = ilookup5_nowait(sb, mft_no, ntfs_test_inode, &na);
962 	}
963 	if (vi) {
964 		ntfs_debug("Base inode 0x%lx is in icache.", mft_no);
965 		/* The inode is in icache. */
966 		ni = NTFS_I(vi);
967 		/* Take a reference to the ntfs inode. */
968 		atomic_inc(&ni->count);
969 		/* If the inode is dirty, do not write this record. */
970 		if (NInoDirty(ni)) {
971 			ntfs_debug("Inode 0x%lx is dirty, do not write it.",
972 					mft_no);
973 			atomic_dec(&ni->count);
974 			iput(vi);
975 			return false;
976 		}
977 		ntfs_debug("Inode 0x%lx is not dirty.", mft_no);
978 		/* The inode is not dirty, try to take the mft record lock. */
979 		if (unlikely(!mutex_trylock(&ni->mrec_lock))) {
980 			ntfs_debug("Mft record 0x%lx is already locked, do "
981 					"not write it.", mft_no);
982 			atomic_dec(&ni->count);
983 			iput(vi);
984 			return false;
985 		}
986 		ntfs_debug("Managed to lock mft record 0x%lx, write it.",
987 				mft_no);
988 		/*
989 		 * The write has to occur while we hold the mft record lock so
990 		 * return the locked ntfs inode.
991 		 */
992 		*locked_ni = ni;
993 		return true;
994 	}
995 	ntfs_debug("Inode 0x%lx is not in icache.", mft_no);
996 	/* The inode is not in icache. */
997 	/* Write the record if it is not a mft record (type "FILE"). */
998 	if (!ntfs_is_mft_record(m->magic)) {
999 		ntfs_debug("Mft record 0x%lx is not a FILE record, write it.",
1000 				mft_no);
1001 		return true;
1002 	}
1003 	/* Write the mft record if it is a base inode. */
1004 	if (!m->base_mft_record) {
1005 		ntfs_debug("Mft record 0x%lx is a base record, write it.",
1006 				mft_no);
1007 		return true;
1008 	}
1009 	/*
1010 	 * This is an extent mft record.  Check if the inode corresponding to
1011 	 * its base mft record is in icache and obtain a reference to it if it
1012 	 * is.
1013 	 */
1014 	na.mft_no = MREF_LE(m->base_mft_record);
1015 	ntfs_debug("Mft record 0x%lx is an extent record.  Looking for base "
1016 			"inode 0x%lx in icache.", mft_no, na.mft_no);
1017 	if (!na.mft_no) {
1018 		/* Balance the below iput(). */
1019 		vi = igrab(mft_vi);
1020 		BUG_ON(vi != mft_vi);
1021 	} else
1022 		vi = ilookup5_nowait(sb, na.mft_no, ntfs_test_inode,
1023 				&na);
1024 	if (!vi) {
1025 		/*
1026 		 * The base inode is not in icache, write this extent mft
1027 		 * record.
1028 		 */
1029 		ntfs_debug("Base inode 0x%lx is not in icache, write the "
1030 				"extent record.", na.mft_no);
1031 		return true;
1032 	}
1033 	ntfs_debug("Base inode 0x%lx is in icache.", na.mft_no);
1034 	/*
1035 	 * The base inode is in icache.  Check if it has the extent inode
1036 	 * corresponding to this extent mft record attached.
1037 	 */
1038 	ni = NTFS_I(vi);
1039 	mutex_lock(&ni->extent_lock);
1040 	if (ni->nr_extents <= 0) {
1041 		/*
1042 		 * The base inode has no attached extent inodes, write this
1043 		 * extent mft record.
1044 		 */
1045 		mutex_unlock(&ni->extent_lock);
1046 		iput(vi);
1047 		ntfs_debug("Base inode 0x%lx has no attached extent inodes, "
1048 				"write the extent record.", na.mft_no);
1049 		return true;
1050 	}
1051 	/* Iterate over the attached extent inodes. */
1052 	extent_nis = ni->ext.extent_ntfs_inos;
1053 	for (eni = NULL, i = 0; i < ni->nr_extents; ++i) {
1054 		if (mft_no == extent_nis[i]->mft_no) {
1055 			/*
1056 			 * Found the extent inode corresponding to this extent
1057 			 * mft record.
1058 			 */
1059 			eni = extent_nis[i];
1060 			break;
1061 		}
1062 	}
1063 	/*
1064 	 * If the extent inode was not attached to the base inode, write this
1065 	 * extent mft record.
1066 	 */
1067 	if (!eni) {
1068 		mutex_unlock(&ni->extent_lock);
1069 		iput(vi);
1070 		ntfs_debug("Extent inode 0x%lx is not attached to its base "
1071 				"inode 0x%lx, write the extent record.",
1072 				mft_no, na.mft_no);
1073 		return true;
1074 	}
1075 	ntfs_debug("Extent inode 0x%lx is attached to its base inode 0x%lx.",
1076 			mft_no, na.mft_no);
1077 	/* Take a reference to the extent ntfs inode. */
1078 	atomic_inc(&eni->count);
1079 	mutex_unlock(&ni->extent_lock);
1080 	/*
1081 	 * Found the extent inode coresponding to this extent mft record.
1082 	 * Try to take the mft record lock.
1083 	 */
1084 	if (unlikely(!mutex_trylock(&eni->mrec_lock))) {
1085 		atomic_dec(&eni->count);
1086 		iput(vi);
1087 		ntfs_debug("Extent mft record 0x%lx is already locked, do "
1088 				"not write it.", mft_no);
1089 		return false;
1090 	}
1091 	ntfs_debug("Managed to lock extent mft record 0x%lx, write it.",
1092 			mft_no);
1093 	if (NInoTestClearDirty(eni))
1094 		ntfs_debug("Extent inode 0x%lx is dirty, marking it clean.",
1095 				mft_no);
1096 	/*
1097 	 * The write has to occur while we hold the mft record lock so return
1098 	 * the locked extent ntfs inode.
1099 	 */
1100 	*locked_ni = eni;
1101 	return true;
1102 }
1103 
1104 static const char *es = "  Leaving inconsistent metadata.  Unmount and run "
1105 		"chkdsk.";
1106 
1107 /**
1108  * ntfs_mft_bitmap_find_and_alloc_free_rec_nolock - see name
1109  * @vol:	volume on which to search for a free mft record
1110  * @base_ni:	open base inode if allocating an extent mft record or NULL
1111  *
1112  * Search for a free mft record in the mft bitmap attribute on the ntfs volume
1113  * @vol.
1114  *
1115  * If @base_ni is NULL start the search at the default allocator position.
1116  *
1117  * If @base_ni is not NULL start the search at the mft record after the base
1118  * mft record @base_ni.
1119  *
1120  * Return the free mft record on success and -errno on error.  An error code of
1121  * -ENOSPC means that there are no free mft records in the currently
1122  * initialized mft bitmap.
1123  *
1124  * Locking: Caller must hold vol->mftbmp_lock for writing.
1125  */
ntfs_mft_bitmap_find_and_alloc_free_rec_nolock(ntfs_volume * vol,ntfs_inode * base_ni)1126 static int ntfs_mft_bitmap_find_and_alloc_free_rec_nolock(ntfs_volume *vol,
1127 		ntfs_inode *base_ni)
1128 {
1129 	s64 pass_end, ll, data_pos, pass_start, ofs, bit;
1130 	unsigned long flags;
1131 	struct address_space *mftbmp_mapping;
1132 	u8 *buf, *byte;
1133 	struct page *page;
1134 	unsigned int page_ofs, size;
1135 	u8 pass, b;
1136 
1137 	ntfs_debug("Searching for free mft record in the currently "
1138 			"initialized mft bitmap.");
1139 	mftbmp_mapping = vol->mftbmp_ino->i_mapping;
1140 	/*
1141 	 * Set the end of the pass making sure we do not overflow the mft
1142 	 * bitmap.
1143 	 */
1144 	read_lock_irqsave(&NTFS_I(vol->mft_ino)->size_lock, flags);
1145 	pass_end = NTFS_I(vol->mft_ino)->allocated_size >>
1146 			vol->mft_record_size_bits;
1147 	read_unlock_irqrestore(&NTFS_I(vol->mft_ino)->size_lock, flags);
1148 	read_lock_irqsave(&NTFS_I(vol->mftbmp_ino)->size_lock, flags);
1149 	ll = NTFS_I(vol->mftbmp_ino)->initialized_size << 3;
1150 	read_unlock_irqrestore(&NTFS_I(vol->mftbmp_ino)->size_lock, flags);
1151 	if (pass_end > ll)
1152 		pass_end = ll;
1153 	pass = 1;
1154 	if (!base_ni)
1155 		data_pos = vol->mft_data_pos;
1156 	else
1157 		data_pos = base_ni->mft_no + 1;
1158 	if (data_pos < 24)
1159 		data_pos = 24;
1160 	if (data_pos >= pass_end) {
1161 		data_pos = 24;
1162 		pass = 2;
1163 		/* This happens on a freshly formatted volume. */
1164 		if (data_pos >= pass_end)
1165 			return -ENOSPC;
1166 	}
1167 	pass_start = data_pos;
1168 	ntfs_debug("Starting bitmap search: pass %u, pass_start 0x%llx, "
1169 			"pass_end 0x%llx, data_pos 0x%llx.", pass,
1170 			(long long)pass_start, (long long)pass_end,
1171 			(long long)data_pos);
1172 	/* Loop until a free mft record is found. */
1173 	for (; pass <= 2;) {
1174 		/* Cap size to pass_end. */
1175 		ofs = data_pos >> 3;
1176 		page_ofs = ofs & ~PAGE_MASK;
1177 		size = PAGE_SIZE - page_ofs;
1178 		ll = ((pass_end + 7) >> 3) - ofs;
1179 		if (size > ll)
1180 			size = ll;
1181 		size <<= 3;
1182 		/*
1183 		 * If we are still within the active pass, search the next page
1184 		 * for a zero bit.
1185 		 */
1186 		if (size) {
1187 			page = ntfs_map_page(mftbmp_mapping,
1188 					ofs >> PAGE_SHIFT);
1189 			if (IS_ERR(page)) {
1190 				ntfs_error(vol->sb, "Failed to read mft "
1191 						"bitmap, aborting.");
1192 				return PTR_ERR(page);
1193 			}
1194 			buf = (u8*)page_address(page) + page_ofs;
1195 			bit = data_pos & 7;
1196 			data_pos &= ~7ull;
1197 			ntfs_debug("Before inner for loop: size 0x%x, "
1198 					"data_pos 0x%llx, bit 0x%llx", size,
1199 					(long long)data_pos, (long long)bit);
1200 			for (; bit < size && data_pos + bit < pass_end;
1201 					bit &= ~7ull, bit += 8) {
1202 				byte = buf + (bit >> 3);
1203 				if (*byte == 0xff)
1204 					continue;
1205 				b = ffz((unsigned long)*byte);
1206 				if (b < 8 && b >= (bit & 7)) {
1207 					ll = data_pos + (bit & ~7ull) + b;
1208 					if (unlikely(ll > (1ll << 32))) {
1209 						ntfs_unmap_page(page);
1210 						return -ENOSPC;
1211 					}
1212 					*byte |= 1 << b;
1213 					flush_dcache_page(page);
1214 					set_page_dirty(page);
1215 					ntfs_unmap_page(page);
1216 					ntfs_debug("Done.  (Found and "
1217 							"allocated mft record "
1218 							"0x%llx.)",
1219 							(long long)ll);
1220 					return ll;
1221 				}
1222 			}
1223 			ntfs_debug("After inner for loop: size 0x%x, "
1224 					"data_pos 0x%llx, bit 0x%llx", size,
1225 					(long long)data_pos, (long long)bit);
1226 			data_pos += size;
1227 			ntfs_unmap_page(page);
1228 			/*
1229 			 * If the end of the pass has not been reached yet,
1230 			 * continue searching the mft bitmap for a zero bit.
1231 			 */
1232 			if (data_pos < pass_end)
1233 				continue;
1234 		}
1235 		/* Do the next pass. */
1236 		if (++pass == 2) {
1237 			/*
1238 			 * Starting the second pass, in which we scan the first
1239 			 * part of the zone which we omitted earlier.
1240 			 */
1241 			pass_end = pass_start;
1242 			data_pos = pass_start = 24;
1243 			ntfs_debug("pass %i, pass_start 0x%llx, pass_end "
1244 					"0x%llx.", pass, (long long)pass_start,
1245 					(long long)pass_end);
1246 			if (data_pos >= pass_end)
1247 				break;
1248 		}
1249 	}
1250 	/* No free mft records in currently initialized mft bitmap. */
1251 	ntfs_debug("Done.  (No free mft records left in currently initialized "
1252 			"mft bitmap.)");
1253 	return -ENOSPC;
1254 }
1255 
1256 /**
1257  * ntfs_mft_bitmap_extend_allocation_nolock - extend mft bitmap by a cluster
1258  * @vol:	volume on which to extend the mft bitmap attribute
1259  *
1260  * Extend the mft bitmap attribute on the ntfs volume @vol by one cluster.
1261  *
1262  * Note: Only changes allocated_size, i.e. does not touch initialized_size or
1263  * data_size.
1264  *
1265  * Return 0 on success and -errno on error.
1266  *
1267  * Locking: - Caller must hold vol->mftbmp_lock for writing.
1268  *	    - This function takes NTFS_I(vol->mftbmp_ino)->runlist.lock for
1269  *	      writing and releases it before returning.
1270  *	    - This function takes vol->lcnbmp_lock for writing and releases it
1271  *	      before returning.
1272  */
ntfs_mft_bitmap_extend_allocation_nolock(ntfs_volume * vol)1273 static int ntfs_mft_bitmap_extend_allocation_nolock(ntfs_volume *vol)
1274 {
1275 	LCN lcn;
1276 	s64 ll;
1277 	unsigned long flags;
1278 	struct page *page;
1279 	ntfs_inode *mft_ni, *mftbmp_ni;
1280 	runlist_element *rl, *rl2 = NULL;
1281 	ntfs_attr_search_ctx *ctx = NULL;
1282 	MFT_RECORD *mrec;
1283 	ATTR_RECORD *a = NULL;
1284 	int ret, mp_size;
1285 	u32 old_alen = 0;
1286 	u8 *b, tb;
1287 	struct {
1288 		u8 added_cluster:1;
1289 		u8 added_run:1;
1290 		u8 mp_rebuilt:1;
1291 	} status = { 0, 0, 0 };
1292 
1293 	ntfs_debug("Extending mft bitmap allocation.");
1294 	mft_ni = NTFS_I(vol->mft_ino);
1295 	mftbmp_ni = NTFS_I(vol->mftbmp_ino);
1296 	/*
1297 	 * Determine the last lcn of the mft bitmap.  The allocated size of the
1298 	 * mft bitmap cannot be zero so we are ok to do this.
1299 	 */
1300 	down_write(&mftbmp_ni->runlist.lock);
1301 	read_lock_irqsave(&mftbmp_ni->size_lock, flags);
1302 	ll = mftbmp_ni->allocated_size;
1303 	read_unlock_irqrestore(&mftbmp_ni->size_lock, flags);
1304 	rl = ntfs_attr_find_vcn_nolock(mftbmp_ni,
1305 			(ll - 1) >> vol->cluster_size_bits, NULL);
1306 	if (IS_ERR(rl) || unlikely(!rl->length || rl->lcn < 0)) {
1307 		up_write(&mftbmp_ni->runlist.lock);
1308 		ntfs_error(vol->sb, "Failed to determine last allocated "
1309 				"cluster of mft bitmap attribute.");
1310 		if (!IS_ERR(rl))
1311 			ret = -EIO;
1312 		else
1313 			ret = PTR_ERR(rl);
1314 		return ret;
1315 	}
1316 	lcn = rl->lcn + rl->length;
1317 	ntfs_debug("Last lcn of mft bitmap attribute is 0x%llx.",
1318 			(long long)lcn);
1319 	/*
1320 	 * Attempt to get the cluster following the last allocated cluster by
1321 	 * hand as it may be in the MFT zone so the allocator would not give it
1322 	 * to us.
1323 	 */
1324 	ll = lcn >> 3;
1325 	page = ntfs_map_page(vol->lcnbmp_ino->i_mapping,
1326 			ll >> PAGE_SHIFT);
1327 	if (IS_ERR(page)) {
1328 		up_write(&mftbmp_ni->runlist.lock);
1329 		ntfs_error(vol->sb, "Failed to read from lcn bitmap.");
1330 		return PTR_ERR(page);
1331 	}
1332 	b = (u8*)page_address(page) + (ll & ~PAGE_MASK);
1333 	tb = 1 << (lcn & 7ull);
1334 	down_write(&vol->lcnbmp_lock);
1335 	if (*b != 0xff && !(*b & tb)) {
1336 		/* Next cluster is free, allocate it. */
1337 		*b |= tb;
1338 		flush_dcache_page(page);
1339 		set_page_dirty(page);
1340 		up_write(&vol->lcnbmp_lock);
1341 		ntfs_unmap_page(page);
1342 		/* Update the mft bitmap runlist. */
1343 		rl->length++;
1344 		rl[1].vcn++;
1345 		status.added_cluster = 1;
1346 		ntfs_debug("Appending one cluster to mft bitmap.");
1347 	} else {
1348 		up_write(&vol->lcnbmp_lock);
1349 		ntfs_unmap_page(page);
1350 		/* Allocate a cluster from the DATA_ZONE. */
1351 		rl2 = ntfs_cluster_alloc(vol, rl[1].vcn, 1, lcn, DATA_ZONE,
1352 				true);
1353 		if (IS_ERR(rl2)) {
1354 			up_write(&mftbmp_ni->runlist.lock);
1355 			ntfs_error(vol->sb, "Failed to allocate a cluster for "
1356 					"the mft bitmap.");
1357 			return PTR_ERR(rl2);
1358 		}
1359 		rl = ntfs_runlists_merge(mftbmp_ni->runlist.rl, rl2);
1360 		if (IS_ERR(rl)) {
1361 			up_write(&mftbmp_ni->runlist.lock);
1362 			ntfs_error(vol->sb, "Failed to merge runlists for mft "
1363 					"bitmap.");
1364 			if (ntfs_cluster_free_from_rl(vol, rl2)) {
1365 				ntfs_error(vol->sb, "Failed to deallocate "
1366 						"allocated cluster.%s", es);
1367 				NVolSetErrors(vol);
1368 			}
1369 			ntfs_free(rl2);
1370 			return PTR_ERR(rl);
1371 		}
1372 		mftbmp_ni->runlist.rl = rl;
1373 		status.added_run = 1;
1374 		ntfs_debug("Adding one run to mft bitmap.");
1375 		/* Find the last run in the new runlist. */
1376 		for (; rl[1].length; rl++)
1377 			;
1378 	}
1379 	/*
1380 	 * Update the attribute record as well.  Note: @rl is the last
1381 	 * (non-terminator) runlist element of mft bitmap.
1382 	 */
1383 	mrec = map_mft_record(mft_ni);
1384 	if (IS_ERR(mrec)) {
1385 		ntfs_error(vol->sb, "Failed to map mft record.");
1386 		ret = PTR_ERR(mrec);
1387 		goto undo_alloc;
1388 	}
1389 	ctx = ntfs_attr_get_search_ctx(mft_ni, mrec);
1390 	if (unlikely(!ctx)) {
1391 		ntfs_error(vol->sb, "Failed to get search context.");
1392 		ret = -ENOMEM;
1393 		goto undo_alloc;
1394 	}
1395 	ret = ntfs_attr_lookup(mftbmp_ni->type, mftbmp_ni->name,
1396 			mftbmp_ni->name_len, CASE_SENSITIVE, rl[1].vcn, NULL,
1397 			0, ctx);
1398 	if (unlikely(ret)) {
1399 		ntfs_error(vol->sb, "Failed to find last attribute extent of "
1400 				"mft bitmap attribute.");
1401 		if (ret == -ENOENT)
1402 			ret = -EIO;
1403 		goto undo_alloc;
1404 	}
1405 	a = ctx->attr;
1406 	ll = sle64_to_cpu(a->data.non_resident.lowest_vcn);
1407 	/* Search back for the previous last allocated cluster of mft bitmap. */
1408 	for (rl2 = rl; rl2 > mftbmp_ni->runlist.rl; rl2--) {
1409 		if (ll >= rl2->vcn)
1410 			break;
1411 	}
1412 	BUG_ON(ll < rl2->vcn);
1413 	BUG_ON(ll >= rl2->vcn + rl2->length);
1414 	/* Get the size for the new mapping pairs array for this extent. */
1415 	mp_size = ntfs_get_size_for_mapping_pairs(vol, rl2, ll, -1);
1416 	if (unlikely(mp_size <= 0)) {
1417 		ntfs_error(vol->sb, "Get size for mapping pairs failed for "
1418 				"mft bitmap attribute extent.");
1419 		ret = mp_size;
1420 		if (!ret)
1421 			ret = -EIO;
1422 		goto undo_alloc;
1423 	}
1424 	/* Expand the attribute record if necessary. */
1425 	old_alen = le32_to_cpu(a->length);
1426 	ret = ntfs_attr_record_resize(ctx->mrec, a, mp_size +
1427 			le16_to_cpu(a->data.non_resident.mapping_pairs_offset));
1428 	if (unlikely(ret)) {
1429 		if (ret != -ENOSPC) {
1430 			ntfs_error(vol->sb, "Failed to resize attribute "
1431 					"record for mft bitmap attribute.");
1432 			goto undo_alloc;
1433 		}
1434 		// TODO: Deal with this by moving this extent to a new mft
1435 		// record or by starting a new extent in a new mft record or by
1436 		// moving other attributes out of this mft record.
1437 		// Note: It will need to be a special mft record and if none of
1438 		// those are available it gets rather complicated...
1439 		ntfs_error(vol->sb, "Not enough space in this mft record to "
1440 				"accommodate extended mft bitmap attribute "
1441 				"extent.  Cannot handle this yet.");
1442 		ret = -EOPNOTSUPP;
1443 		goto undo_alloc;
1444 	}
1445 	status.mp_rebuilt = 1;
1446 	/* Generate the mapping pairs array directly into the attr record. */
1447 	ret = ntfs_mapping_pairs_build(vol, (u8*)a +
1448 			le16_to_cpu(a->data.non_resident.mapping_pairs_offset),
1449 			mp_size, rl2, ll, -1, NULL);
1450 	if (unlikely(ret)) {
1451 		ntfs_error(vol->sb, "Failed to build mapping pairs array for "
1452 				"mft bitmap attribute.");
1453 		goto undo_alloc;
1454 	}
1455 	/* Update the highest_vcn. */
1456 	a->data.non_resident.highest_vcn = cpu_to_sle64(rl[1].vcn - 1);
1457 	/*
1458 	 * We now have extended the mft bitmap allocated_size by one cluster.
1459 	 * Reflect this in the ntfs_inode structure and the attribute record.
1460 	 */
1461 	if (a->data.non_resident.lowest_vcn) {
1462 		/*
1463 		 * We are not in the first attribute extent, switch to it, but
1464 		 * first ensure the changes will make it to disk later.
1465 		 */
1466 		flush_dcache_mft_record_page(ctx->ntfs_ino);
1467 		mark_mft_record_dirty(ctx->ntfs_ino);
1468 		ntfs_attr_reinit_search_ctx(ctx);
1469 		ret = ntfs_attr_lookup(mftbmp_ni->type, mftbmp_ni->name,
1470 				mftbmp_ni->name_len, CASE_SENSITIVE, 0, NULL,
1471 				0, ctx);
1472 		if (unlikely(ret)) {
1473 			ntfs_error(vol->sb, "Failed to find first attribute "
1474 					"extent of mft bitmap attribute.");
1475 			goto restore_undo_alloc;
1476 		}
1477 		a = ctx->attr;
1478 	}
1479 	write_lock_irqsave(&mftbmp_ni->size_lock, flags);
1480 	mftbmp_ni->allocated_size += vol->cluster_size;
1481 	a->data.non_resident.allocated_size =
1482 			cpu_to_sle64(mftbmp_ni->allocated_size);
1483 	write_unlock_irqrestore(&mftbmp_ni->size_lock, flags);
1484 	/* Ensure the changes make it to disk. */
1485 	flush_dcache_mft_record_page(ctx->ntfs_ino);
1486 	mark_mft_record_dirty(ctx->ntfs_ino);
1487 	ntfs_attr_put_search_ctx(ctx);
1488 	unmap_mft_record(mft_ni);
1489 	up_write(&mftbmp_ni->runlist.lock);
1490 	ntfs_debug("Done.");
1491 	return 0;
1492 restore_undo_alloc:
1493 	ntfs_attr_reinit_search_ctx(ctx);
1494 	if (ntfs_attr_lookup(mftbmp_ni->type, mftbmp_ni->name,
1495 			mftbmp_ni->name_len, CASE_SENSITIVE, rl[1].vcn, NULL,
1496 			0, ctx)) {
1497 		ntfs_error(vol->sb, "Failed to find last attribute extent of "
1498 				"mft bitmap attribute.%s", es);
1499 		write_lock_irqsave(&mftbmp_ni->size_lock, flags);
1500 		mftbmp_ni->allocated_size += vol->cluster_size;
1501 		write_unlock_irqrestore(&mftbmp_ni->size_lock, flags);
1502 		ntfs_attr_put_search_ctx(ctx);
1503 		unmap_mft_record(mft_ni);
1504 		up_write(&mftbmp_ni->runlist.lock);
1505 		/*
1506 		 * The only thing that is now wrong is ->allocated_size of the
1507 		 * base attribute extent which chkdsk should be able to fix.
1508 		 */
1509 		NVolSetErrors(vol);
1510 		return ret;
1511 	}
1512 	a = ctx->attr;
1513 	a->data.non_resident.highest_vcn = cpu_to_sle64(rl[1].vcn - 2);
1514 undo_alloc:
1515 	if (status.added_cluster) {
1516 		/* Truncate the last run in the runlist by one cluster. */
1517 		rl->length--;
1518 		rl[1].vcn--;
1519 	} else if (status.added_run) {
1520 		lcn = rl->lcn;
1521 		/* Remove the last run from the runlist. */
1522 		rl->lcn = rl[1].lcn;
1523 		rl->length = 0;
1524 	}
1525 	/* Deallocate the cluster. */
1526 	down_write(&vol->lcnbmp_lock);
1527 	if (ntfs_bitmap_clear_bit(vol->lcnbmp_ino, lcn)) {
1528 		ntfs_error(vol->sb, "Failed to free allocated cluster.%s", es);
1529 		NVolSetErrors(vol);
1530 	}
1531 	up_write(&vol->lcnbmp_lock);
1532 	if (status.mp_rebuilt) {
1533 		if (ntfs_mapping_pairs_build(vol, (u8*)a + le16_to_cpu(
1534 				a->data.non_resident.mapping_pairs_offset),
1535 				old_alen - le16_to_cpu(
1536 				a->data.non_resident.mapping_pairs_offset),
1537 				rl2, ll, -1, NULL)) {
1538 			ntfs_error(vol->sb, "Failed to restore mapping pairs "
1539 					"array.%s", es);
1540 			NVolSetErrors(vol);
1541 		}
1542 		if (ntfs_attr_record_resize(ctx->mrec, a, old_alen)) {
1543 			ntfs_error(vol->sb, "Failed to restore attribute "
1544 					"record.%s", es);
1545 			NVolSetErrors(vol);
1546 		}
1547 		flush_dcache_mft_record_page(ctx->ntfs_ino);
1548 		mark_mft_record_dirty(ctx->ntfs_ino);
1549 	}
1550 	if (ctx)
1551 		ntfs_attr_put_search_ctx(ctx);
1552 	if (!IS_ERR(mrec))
1553 		unmap_mft_record(mft_ni);
1554 	up_write(&mftbmp_ni->runlist.lock);
1555 	return ret;
1556 }
1557 
1558 /**
1559  * ntfs_mft_bitmap_extend_initialized_nolock - extend mftbmp initialized data
1560  * @vol:	volume on which to extend the mft bitmap attribute
1561  *
1562  * Extend the initialized portion of the mft bitmap attribute on the ntfs
1563  * volume @vol by 8 bytes.
1564  *
1565  * Note:  Only changes initialized_size and data_size, i.e. requires that
1566  * allocated_size is big enough to fit the new initialized_size.
1567  *
1568  * Return 0 on success and -error on error.
1569  *
1570  * Locking: Caller must hold vol->mftbmp_lock for writing.
1571  */
ntfs_mft_bitmap_extend_initialized_nolock(ntfs_volume * vol)1572 static int ntfs_mft_bitmap_extend_initialized_nolock(ntfs_volume *vol)
1573 {
1574 	s64 old_data_size, old_initialized_size;
1575 	unsigned long flags;
1576 	struct inode *mftbmp_vi;
1577 	ntfs_inode *mft_ni, *mftbmp_ni;
1578 	ntfs_attr_search_ctx *ctx;
1579 	MFT_RECORD *mrec;
1580 	ATTR_RECORD *a;
1581 	int ret;
1582 
1583 	ntfs_debug("Extending mft bitmap initiailized (and data) size.");
1584 	mft_ni = NTFS_I(vol->mft_ino);
1585 	mftbmp_vi = vol->mftbmp_ino;
1586 	mftbmp_ni = NTFS_I(mftbmp_vi);
1587 	/* Get the attribute record. */
1588 	mrec = map_mft_record(mft_ni);
1589 	if (IS_ERR(mrec)) {
1590 		ntfs_error(vol->sb, "Failed to map mft record.");
1591 		return PTR_ERR(mrec);
1592 	}
1593 	ctx = ntfs_attr_get_search_ctx(mft_ni, mrec);
1594 	if (unlikely(!ctx)) {
1595 		ntfs_error(vol->sb, "Failed to get search context.");
1596 		ret = -ENOMEM;
1597 		goto unm_err_out;
1598 	}
1599 	ret = ntfs_attr_lookup(mftbmp_ni->type, mftbmp_ni->name,
1600 			mftbmp_ni->name_len, CASE_SENSITIVE, 0, NULL, 0, ctx);
1601 	if (unlikely(ret)) {
1602 		ntfs_error(vol->sb, "Failed to find first attribute extent of "
1603 				"mft bitmap attribute.");
1604 		if (ret == -ENOENT)
1605 			ret = -EIO;
1606 		goto put_err_out;
1607 	}
1608 	a = ctx->attr;
1609 	write_lock_irqsave(&mftbmp_ni->size_lock, flags);
1610 	old_data_size = i_size_read(mftbmp_vi);
1611 	old_initialized_size = mftbmp_ni->initialized_size;
1612 	/*
1613 	 * We can simply update the initialized_size before filling the space
1614 	 * with zeroes because the caller is holding the mft bitmap lock for
1615 	 * writing which ensures that no one else is trying to access the data.
1616 	 */
1617 	mftbmp_ni->initialized_size += 8;
1618 	a->data.non_resident.initialized_size =
1619 			cpu_to_sle64(mftbmp_ni->initialized_size);
1620 	if (mftbmp_ni->initialized_size > old_data_size) {
1621 		i_size_write(mftbmp_vi, mftbmp_ni->initialized_size);
1622 		a->data.non_resident.data_size =
1623 				cpu_to_sle64(mftbmp_ni->initialized_size);
1624 	}
1625 	write_unlock_irqrestore(&mftbmp_ni->size_lock, flags);
1626 	/* Ensure the changes make it to disk. */
1627 	flush_dcache_mft_record_page(ctx->ntfs_ino);
1628 	mark_mft_record_dirty(ctx->ntfs_ino);
1629 	ntfs_attr_put_search_ctx(ctx);
1630 	unmap_mft_record(mft_ni);
1631 	/* Initialize the mft bitmap attribute value with zeroes. */
1632 	ret = ntfs_attr_set(mftbmp_ni, old_initialized_size, 8, 0);
1633 	if (likely(!ret)) {
1634 		ntfs_debug("Done.  (Wrote eight initialized bytes to mft "
1635 				"bitmap.");
1636 		return 0;
1637 	}
1638 	ntfs_error(vol->sb, "Failed to write to mft bitmap.");
1639 	/* Try to recover from the error. */
1640 	mrec = map_mft_record(mft_ni);
1641 	if (IS_ERR(mrec)) {
1642 		ntfs_error(vol->sb, "Failed to map mft record.%s", es);
1643 		NVolSetErrors(vol);
1644 		return ret;
1645 	}
1646 	ctx = ntfs_attr_get_search_ctx(mft_ni, mrec);
1647 	if (unlikely(!ctx)) {
1648 		ntfs_error(vol->sb, "Failed to get search context.%s", es);
1649 		NVolSetErrors(vol);
1650 		goto unm_err_out;
1651 	}
1652 	if (ntfs_attr_lookup(mftbmp_ni->type, mftbmp_ni->name,
1653 			mftbmp_ni->name_len, CASE_SENSITIVE, 0, NULL, 0, ctx)) {
1654 		ntfs_error(vol->sb, "Failed to find first attribute extent of "
1655 				"mft bitmap attribute.%s", es);
1656 		NVolSetErrors(vol);
1657 put_err_out:
1658 		ntfs_attr_put_search_ctx(ctx);
1659 unm_err_out:
1660 		unmap_mft_record(mft_ni);
1661 		goto err_out;
1662 	}
1663 	a = ctx->attr;
1664 	write_lock_irqsave(&mftbmp_ni->size_lock, flags);
1665 	mftbmp_ni->initialized_size = old_initialized_size;
1666 	a->data.non_resident.initialized_size =
1667 			cpu_to_sle64(old_initialized_size);
1668 	if (i_size_read(mftbmp_vi) != old_data_size) {
1669 		i_size_write(mftbmp_vi, old_data_size);
1670 		a->data.non_resident.data_size = cpu_to_sle64(old_data_size);
1671 	}
1672 	write_unlock_irqrestore(&mftbmp_ni->size_lock, flags);
1673 	flush_dcache_mft_record_page(ctx->ntfs_ino);
1674 	mark_mft_record_dirty(ctx->ntfs_ino);
1675 	ntfs_attr_put_search_ctx(ctx);
1676 	unmap_mft_record(mft_ni);
1677 #ifdef DEBUG
1678 	read_lock_irqsave(&mftbmp_ni->size_lock, flags);
1679 	ntfs_debug("Restored status of mftbmp: allocated_size 0x%llx, "
1680 			"data_size 0x%llx, initialized_size 0x%llx.",
1681 			(long long)mftbmp_ni->allocated_size,
1682 			(long long)i_size_read(mftbmp_vi),
1683 			(long long)mftbmp_ni->initialized_size);
1684 	read_unlock_irqrestore(&mftbmp_ni->size_lock, flags);
1685 #endif /* DEBUG */
1686 err_out:
1687 	return ret;
1688 }
1689 
1690 /**
1691  * ntfs_mft_data_extend_allocation_nolock - extend mft data attribute
1692  * @vol:	volume on which to extend the mft data attribute
1693  *
1694  * Extend the mft data attribute on the ntfs volume @vol by 16 mft records
1695  * worth of clusters or if not enough space for this by one mft record worth
1696  * of clusters.
1697  *
1698  * Note:  Only changes allocated_size, i.e. does not touch initialized_size or
1699  * data_size.
1700  *
1701  * Return 0 on success and -errno on error.
1702  *
1703  * Locking: - Caller must hold vol->mftbmp_lock for writing.
1704  *	    - This function takes NTFS_I(vol->mft_ino)->runlist.lock for
1705  *	      writing and releases it before returning.
1706  *	    - This function calls functions which take vol->lcnbmp_lock for
1707  *	      writing and release it before returning.
1708  */
ntfs_mft_data_extend_allocation_nolock(ntfs_volume * vol)1709 static int ntfs_mft_data_extend_allocation_nolock(ntfs_volume *vol)
1710 {
1711 	LCN lcn;
1712 	VCN old_last_vcn;
1713 	s64 min_nr, nr, ll;
1714 	unsigned long flags;
1715 	ntfs_inode *mft_ni;
1716 	runlist_element *rl, *rl2;
1717 	ntfs_attr_search_ctx *ctx = NULL;
1718 	MFT_RECORD *mrec;
1719 	ATTR_RECORD *a = NULL;
1720 	int ret, mp_size;
1721 	u32 old_alen = 0;
1722 	bool mp_rebuilt = false;
1723 
1724 	ntfs_debug("Extending mft data allocation.");
1725 	mft_ni = NTFS_I(vol->mft_ino);
1726 	/*
1727 	 * Determine the preferred allocation location, i.e. the last lcn of
1728 	 * the mft data attribute.  The allocated size of the mft data
1729 	 * attribute cannot be zero so we are ok to do this.
1730 	 */
1731 	down_write(&mft_ni->runlist.lock);
1732 	read_lock_irqsave(&mft_ni->size_lock, flags);
1733 	ll = mft_ni->allocated_size;
1734 	read_unlock_irqrestore(&mft_ni->size_lock, flags);
1735 	rl = ntfs_attr_find_vcn_nolock(mft_ni,
1736 			(ll - 1) >> vol->cluster_size_bits, NULL);
1737 	if (IS_ERR(rl) || unlikely(!rl->length || rl->lcn < 0)) {
1738 		up_write(&mft_ni->runlist.lock);
1739 		ntfs_error(vol->sb, "Failed to determine last allocated "
1740 				"cluster of mft data attribute.");
1741 		if (!IS_ERR(rl))
1742 			ret = -EIO;
1743 		else
1744 			ret = PTR_ERR(rl);
1745 		return ret;
1746 	}
1747 	lcn = rl->lcn + rl->length;
1748 	ntfs_debug("Last lcn of mft data attribute is 0x%llx.", (long long)lcn);
1749 	/* Minimum allocation is one mft record worth of clusters. */
1750 	min_nr = vol->mft_record_size >> vol->cluster_size_bits;
1751 	if (!min_nr)
1752 		min_nr = 1;
1753 	/* Want to allocate 16 mft records worth of clusters. */
1754 	nr = vol->mft_record_size << 4 >> vol->cluster_size_bits;
1755 	if (!nr)
1756 		nr = min_nr;
1757 	/* Ensure we do not go above 2^32-1 mft records. */
1758 	read_lock_irqsave(&mft_ni->size_lock, flags);
1759 	ll = mft_ni->allocated_size;
1760 	read_unlock_irqrestore(&mft_ni->size_lock, flags);
1761 	if (unlikely((ll + (nr << vol->cluster_size_bits)) >>
1762 			vol->mft_record_size_bits >= (1ll << 32))) {
1763 		nr = min_nr;
1764 		if (unlikely((ll + (nr << vol->cluster_size_bits)) >>
1765 				vol->mft_record_size_bits >= (1ll << 32))) {
1766 			ntfs_warning(vol->sb, "Cannot allocate mft record "
1767 					"because the maximum number of inodes "
1768 					"(2^32) has already been reached.");
1769 			up_write(&mft_ni->runlist.lock);
1770 			return -ENOSPC;
1771 		}
1772 	}
1773 	ntfs_debug("Trying mft data allocation with %s cluster count %lli.",
1774 			nr > min_nr ? "default" : "minimal", (long long)nr);
1775 	old_last_vcn = rl[1].vcn;
1776 	do {
1777 		rl2 = ntfs_cluster_alloc(vol, old_last_vcn, nr, lcn, MFT_ZONE,
1778 				true);
1779 		if (!IS_ERR(rl2))
1780 			break;
1781 		if (PTR_ERR(rl2) != -ENOSPC || nr == min_nr) {
1782 			ntfs_error(vol->sb, "Failed to allocate the minimal "
1783 					"number of clusters (%lli) for the "
1784 					"mft data attribute.", (long long)nr);
1785 			up_write(&mft_ni->runlist.lock);
1786 			return PTR_ERR(rl2);
1787 		}
1788 		/*
1789 		 * There is not enough space to do the allocation, but there
1790 		 * might be enough space to do a minimal allocation so try that
1791 		 * before failing.
1792 		 */
1793 		nr = min_nr;
1794 		ntfs_debug("Retrying mft data allocation with minimal cluster "
1795 				"count %lli.", (long long)nr);
1796 	} while (1);
1797 	rl = ntfs_runlists_merge(mft_ni->runlist.rl, rl2);
1798 	if (IS_ERR(rl)) {
1799 		up_write(&mft_ni->runlist.lock);
1800 		ntfs_error(vol->sb, "Failed to merge runlists for mft data "
1801 				"attribute.");
1802 		if (ntfs_cluster_free_from_rl(vol, rl2)) {
1803 			ntfs_error(vol->sb, "Failed to deallocate clusters "
1804 					"from the mft data attribute.%s", es);
1805 			NVolSetErrors(vol);
1806 		}
1807 		ntfs_free(rl2);
1808 		return PTR_ERR(rl);
1809 	}
1810 	mft_ni->runlist.rl = rl;
1811 	ntfs_debug("Allocated %lli clusters.", (long long)nr);
1812 	/* Find the last run in the new runlist. */
1813 	for (; rl[1].length; rl++)
1814 		;
1815 	/* Update the attribute record as well. */
1816 	mrec = map_mft_record(mft_ni);
1817 	if (IS_ERR(mrec)) {
1818 		ntfs_error(vol->sb, "Failed to map mft record.");
1819 		ret = PTR_ERR(mrec);
1820 		goto undo_alloc;
1821 	}
1822 	ctx = ntfs_attr_get_search_ctx(mft_ni, mrec);
1823 	if (unlikely(!ctx)) {
1824 		ntfs_error(vol->sb, "Failed to get search context.");
1825 		ret = -ENOMEM;
1826 		goto undo_alloc;
1827 	}
1828 	ret = ntfs_attr_lookup(mft_ni->type, mft_ni->name, mft_ni->name_len,
1829 			CASE_SENSITIVE, rl[1].vcn, NULL, 0, ctx);
1830 	if (unlikely(ret)) {
1831 		ntfs_error(vol->sb, "Failed to find last attribute extent of "
1832 				"mft data attribute.");
1833 		if (ret == -ENOENT)
1834 			ret = -EIO;
1835 		goto undo_alloc;
1836 	}
1837 	a = ctx->attr;
1838 	ll = sle64_to_cpu(a->data.non_resident.lowest_vcn);
1839 	/* Search back for the previous last allocated cluster of mft bitmap. */
1840 	for (rl2 = rl; rl2 > mft_ni->runlist.rl; rl2--) {
1841 		if (ll >= rl2->vcn)
1842 			break;
1843 	}
1844 	BUG_ON(ll < rl2->vcn);
1845 	BUG_ON(ll >= rl2->vcn + rl2->length);
1846 	/* Get the size for the new mapping pairs array for this extent. */
1847 	mp_size = ntfs_get_size_for_mapping_pairs(vol, rl2, ll, -1);
1848 	if (unlikely(mp_size <= 0)) {
1849 		ntfs_error(vol->sb, "Get size for mapping pairs failed for "
1850 				"mft data attribute extent.");
1851 		ret = mp_size;
1852 		if (!ret)
1853 			ret = -EIO;
1854 		goto undo_alloc;
1855 	}
1856 	/* Expand the attribute record if necessary. */
1857 	old_alen = le32_to_cpu(a->length);
1858 	ret = ntfs_attr_record_resize(ctx->mrec, a, mp_size +
1859 			le16_to_cpu(a->data.non_resident.mapping_pairs_offset));
1860 	if (unlikely(ret)) {
1861 		if (ret != -ENOSPC) {
1862 			ntfs_error(vol->sb, "Failed to resize attribute "
1863 					"record for mft data attribute.");
1864 			goto undo_alloc;
1865 		}
1866 		// TODO: Deal with this by moving this extent to a new mft
1867 		// record or by starting a new extent in a new mft record or by
1868 		// moving other attributes out of this mft record.
1869 		// Note: Use the special reserved mft records and ensure that
1870 		// this extent is not required to find the mft record in
1871 		// question.  If no free special records left we would need to
1872 		// move an existing record away, insert ours in its place, and
1873 		// then place the moved record into the newly allocated space
1874 		// and we would then need to update all references to this mft
1875 		// record appropriately.  This is rather complicated...
1876 		ntfs_error(vol->sb, "Not enough space in this mft record to "
1877 				"accommodate extended mft data attribute "
1878 				"extent.  Cannot handle this yet.");
1879 		ret = -EOPNOTSUPP;
1880 		goto undo_alloc;
1881 	}
1882 	mp_rebuilt = true;
1883 	/* Generate the mapping pairs array directly into the attr record. */
1884 	ret = ntfs_mapping_pairs_build(vol, (u8*)a +
1885 			le16_to_cpu(a->data.non_resident.mapping_pairs_offset),
1886 			mp_size, rl2, ll, -1, NULL);
1887 	if (unlikely(ret)) {
1888 		ntfs_error(vol->sb, "Failed to build mapping pairs array of "
1889 				"mft data attribute.");
1890 		goto undo_alloc;
1891 	}
1892 	/* Update the highest_vcn. */
1893 	a->data.non_resident.highest_vcn = cpu_to_sle64(rl[1].vcn - 1);
1894 	/*
1895 	 * We now have extended the mft data allocated_size by nr clusters.
1896 	 * Reflect this in the ntfs_inode structure and the attribute record.
1897 	 * @rl is the last (non-terminator) runlist element of mft data
1898 	 * attribute.
1899 	 */
1900 	if (a->data.non_resident.lowest_vcn) {
1901 		/*
1902 		 * We are not in the first attribute extent, switch to it, but
1903 		 * first ensure the changes will make it to disk later.
1904 		 */
1905 		flush_dcache_mft_record_page(ctx->ntfs_ino);
1906 		mark_mft_record_dirty(ctx->ntfs_ino);
1907 		ntfs_attr_reinit_search_ctx(ctx);
1908 		ret = ntfs_attr_lookup(mft_ni->type, mft_ni->name,
1909 				mft_ni->name_len, CASE_SENSITIVE, 0, NULL, 0,
1910 				ctx);
1911 		if (unlikely(ret)) {
1912 			ntfs_error(vol->sb, "Failed to find first attribute "
1913 					"extent of mft data attribute.");
1914 			goto restore_undo_alloc;
1915 		}
1916 		a = ctx->attr;
1917 	}
1918 	write_lock_irqsave(&mft_ni->size_lock, flags);
1919 	mft_ni->allocated_size += nr << vol->cluster_size_bits;
1920 	a->data.non_resident.allocated_size =
1921 			cpu_to_sle64(mft_ni->allocated_size);
1922 	write_unlock_irqrestore(&mft_ni->size_lock, flags);
1923 	/* Ensure the changes make it to disk. */
1924 	flush_dcache_mft_record_page(ctx->ntfs_ino);
1925 	mark_mft_record_dirty(ctx->ntfs_ino);
1926 	ntfs_attr_put_search_ctx(ctx);
1927 	unmap_mft_record(mft_ni);
1928 	up_write(&mft_ni->runlist.lock);
1929 	ntfs_debug("Done.");
1930 	return 0;
1931 restore_undo_alloc:
1932 	ntfs_attr_reinit_search_ctx(ctx);
1933 	if (ntfs_attr_lookup(mft_ni->type, mft_ni->name, mft_ni->name_len,
1934 			CASE_SENSITIVE, rl[1].vcn, NULL, 0, ctx)) {
1935 		ntfs_error(vol->sb, "Failed to find last attribute extent of "
1936 				"mft data attribute.%s", es);
1937 		write_lock_irqsave(&mft_ni->size_lock, flags);
1938 		mft_ni->allocated_size += nr << vol->cluster_size_bits;
1939 		write_unlock_irqrestore(&mft_ni->size_lock, flags);
1940 		ntfs_attr_put_search_ctx(ctx);
1941 		unmap_mft_record(mft_ni);
1942 		up_write(&mft_ni->runlist.lock);
1943 		/*
1944 		 * The only thing that is now wrong is ->allocated_size of the
1945 		 * base attribute extent which chkdsk should be able to fix.
1946 		 */
1947 		NVolSetErrors(vol);
1948 		return ret;
1949 	}
1950 	ctx->attr->data.non_resident.highest_vcn =
1951 			cpu_to_sle64(old_last_vcn - 1);
1952 undo_alloc:
1953 	if (ntfs_cluster_free(mft_ni, old_last_vcn, -1, ctx) < 0) {
1954 		ntfs_error(vol->sb, "Failed to free clusters from mft data "
1955 				"attribute.%s", es);
1956 		NVolSetErrors(vol);
1957 	}
1958 	a = ctx->attr;
1959 	if (ntfs_rl_truncate_nolock(vol, &mft_ni->runlist, old_last_vcn)) {
1960 		ntfs_error(vol->sb, "Failed to truncate mft data attribute "
1961 				"runlist.%s", es);
1962 		NVolSetErrors(vol);
1963 	}
1964 	if (mp_rebuilt && !IS_ERR(ctx->mrec)) {
1965 		if (ntfs_mapping_pairs_build(vol, (u8*)a + le16_to_cpu(
1966 				a->data.non_resident.mapping_pairs_offset),
1967 				old_alen - le16_to_cpu(
1968 				a->data.non_resident.mapping_pairs_offset),
1969 				rl2, ll, -1, NULL)) {
1970 			ntfs_error(vol->sb, "Failed to restore mapping pairs "
1971 					"array.%s", es);
1972 			NVolSetErrors(vol);
1973 		}
1974 		if (ntfs_attr_record_resize(ctx->mrec, a, old_alen)) {
1975 			ntfs_error(vol->sb, "Failed to restore attribute "
1976 					"record.%s", es);
1977 			NVolSetErrors(vol);
1978 		}
1979 		flush_dcache_mft_record_page(ctx->ntfs_ino);
1980 		mark_mft_record_dirty(ctx->ntfs_ino);
1981 	} else if (IS_ERR(ctx->mrec)) {
1982 		ntfs_error(vol->sb, "Failed to restore attribute search "
1983 				"context.%s", es);
1984 		NVolSetErrors(vol);
1985 	}
1986 	if (ctx)
1987 		ntfs_attr_put_search_ctx(ctx);
1988 	if (!IS_ERR(mrec))
1989 		unmap_mft_record(mft_ni);
1990 	up_write(&mft_ni->runlist.lock);
1991 	return ret;
1992 }
1993 
1994 /**
1995  * ntfs_mft_record_layout - layout an mft record into a memory buffer
1996  * @vol:	volume to which the mft record will belong
1997  * @mft_no:	mft reference specifying the mft record number
1998  * @m:		destination buffer of size >= @vol->mft_record_size bytes
1999  *
2000  * Layout an empty, unused mft record with the mft record number @mft_no into
2001  * the buffer @m.  The volume @vol is needed because the mft record structure
2002  * was modified in NTFS 3.1 so we need to know which volume version this mft
2003  * record will be used on.
2004  *
2005  * Return 0 on success and -errno on error.
2006  */
ntfs_mft_record_layout(const ntfs_volume * vol,const s64 mft_no,MFT_RECORD * m)2007 static int ntfs_mft_record_layout(const ntfs_volume *vol, const s64 mft_no,
2008 		MFT_RECORD *m)
2009 {
2010 	ATTR_RECORD *a;
2011 
2012 	ntfs_debug("Entering for mft record 0x%llx.", (long long)mft_no);
2013 	if (mft_no >= (1ll << 32)) {
2014 		ntfs_error(vol->sb, "Mft record number 0x%llx exceeds "
2015 				"maximum of 2^32.", (long long)mft_no);
2016 		return -ERANGE;
2017 	}
2018 	/* Start by clearing the whole mft record to gives us a clean slate. */
2019 	memset(m, 0, vol->mft_record_size);
2020 	/* Aligned to 2-byte boundary. */
2021 	if (vol->major_ver < 3 || (vol->major_ver == 3 && !vol->minor_ver))
2022 		m->usa_ofs = cpu_to_le16((sizeof(MFT_RECORD_OLD) + 1) & ~1);
2023 	else {
2024 		m->usa_ofs = cpu_to_le16((sizeof(MFT_RECORD) + 1) & ~1);
2025 		/*
2026 		 * Set the NTFS 3.1+ specific fields while we know that the
2027 		 * volume version is 3.1+.
2028 		 */
2029 		m->reserved = 0;
2030 		m->mft_record_number = cpu_to_le32((u32)mft_no);
2031 	}
2032 	m->magic = magic_FILE;
2033 	if (vol->mft_record_size >= NTFS_BLOCK_SIZE)
2034 		m->usa_count = cpu_to_le16(vol->mft_record_size /
2035 				NTFS_BLOCK_SIZE + 1);
2036 	else {
2037 		m->usa_count = cpu_to_le16(1);
2038 		ntfs_warning(vol->sb, "Sector size is bigger than mft record "
2039 				"size.  Setting usa_count to 1.  If chkdsk "
2040 				"reports this as corruption, please email "
2041 				"linux-ntfs-dev@lists.sourceforge.net stating "
2042 				"that you saw this message and that the "
2043 				"modified filesystem created was corrupt.  "
2044 				"Thank you.");
2045 	}
2046 	/* Set the update sequence number to 1. */
2047 	*(le16*)((u8*)m + le16_to_cpu(m->usa_ofs)) = cpu_to_le16(1);
2048 	m->lsn = 0;
2049 	m->sequence_number = cpu_to_le16(1);
2050 	m->link_count = 0;
2051 	/*
2052 	 * Place the attributes straight after the update sequence array,
2053 	 * aligned to 8-byte boundary.
2054 	 */
2055 	m->attrs_offset = cpu_to_le16((le16_to_cpu(m->usa_ofs) +
2056 			(le16_to_cpu(m->usa_count) << 1) + 7) & ~7);
2057 	m->flags = 0;
2058 	/*
2059 	 * Using attrs_offset plus eight bytes (for the termination attribute).
2060 	 * attrs_offset is already aligned to 8-byte boundary, so no need to
2061 	 * align again.
2062 	 */
2063 	m->bytes_in_use = cpu_to_le32(le16_to_cpu(m->attrs_offset) + 8);
2064 	m->bytes_allocated = cpu_to_le32(vol->mft_record_size);
2065 	m->base_mft_record = 0;
2066 	m->next_attr_instance = 0;
2067 	/* Add the termination attribute. */
2068 	a = (ATTR_RECORD*)((u8*)m + le16_to_cpu(m->attrs_offset));
2069 	a->type = AT_END;
2070 	a->length = 0;
2071 	ntfs_debug("Done.");
2072 	return 0;
2073 }
2074 
2075 /**
2076  * ntfs_mft_record_format - format an mft record on an ntfs volume
2077  * @vol:	volume on which to format the mft record
2078  * @mft_no:	mft record number to format
2079  *
2080  * Format the mft record @mft_no in $MFT/$DATA, i.e. lay out an empty, unused
2081  * mft record into the appropriate place of the mft data attribute.  This is
2082  * used when extending the mft data attribute.
2083  *
2084  * Return 0 on success and -errno on error.
2085  */
ntfs_mft_record_format(const ntfs_volume * vol,const s64 mft_no)2086 static int ntfs_mft_record_format(const ntfs_volume *vol, const s64 mft_no)
2087 {
2088 	loff_t i_size;
2089 	struct inode *mft_vi = vol->mft_ino;
2090 	struct page *page;
2091 	MFT_RECORD *m;
2092 	pgoff_t index, end_index;
2093 	unsigned int ofs;
2094 	int err;
2095 
2096 	ntfs_debug("Entering for mft record 0x%llx.", (long long)mft_no);
2097 	/*
2098 	 * The index into the page cache and the offset within the page cache
2099 	 * page of the wanted mft record.
2100 	 */
2101 	index = mft_no << vol->mft_record_size_bits >> PAGE_SHIFT;
2102 	ofs = (mft_no << vol->mft_record_size_bits) & ~PAGE_MASK;
2103 	/* The maximum valid index into the page cache for $MFT's data. */
2104 	i_size = i_size_read(mft_vi);
2105 	end_index = i_size >> PAGE_SHIFT;
2106 	if (unlikely(index >= end_index)) {
2107 		if (unlikely(index > end_index || ofs + vol->mft_record_size >=
2108 				(i_size & ~PAGE_MASK))) {
2109 			ntfs_error(vol->sb, "Tried to format non-existing mft "
2110 					"record 0x%llx.", (long long)mft_no);
2111 			return -ENOENT;
2112 		}
2113 	}
2114 	/* Read, map, and pin the page containing the mft record. */
2115 	page = ntfs_map_page(mft_vi->i_mapping, index);
2116 	if (IS_ERR(page)) {
2117 		ntfs_error(vol->sb, "Failed to map page containing mft record "
2118 				"to format 0x%llx.", (long long)mft_no);
2119 		return PTR_ERR(page);
2120 	}
2121 	lock_page(page);
2122 	BUG_ON(!PageUptodate(page));
2123 	ClearPageUptodate(page);
2124 	m = (MFT_RECORD*)((u8*)page_address(page) + ofs);
2125 	err = ntfs_mft_record_layout(vol, mft_no, m);
2126 	if (unlikely(err)) {
2127 		ntfs_error(vol->sb, "Failed to layout mft record 0x%llx.",
2128 				(long long)mft_no);
2129 		SetPageUptodate(page);
2130 		unlock_page(page);
2131 		ntfs_unmap_page(page);
2132 		return err;
2133 	}
2134 	flush_dcache_page(page);
2135 	SetPageUptodate(page);
2136 	unlock_page(page);
2137 	/*
2138 	 * Make sure the mft record is written out to disk.  We could use
2139 	 * ilookup5() to check if an inode is in icache and so on but this is
2140 	 * unnecessary as ntfs_writepage() will write the dirty record anyway.
2141 	 */
2142 	mark_ntfs_record_dirty(page, ofs);
2143 	ntfs_unmap_page(page);
2144 	ntfs_debug("Done.");
2145 	return 0;
2146 }
2147 
2148 /**
2149  * ntfs_mft_record_alloc - allocate an mft record on an ntfs volume
2150  * @vol:	[IN]  volume on which to allocate the mft record
2151  * @mode:	[IN]  mode if want a file or directory, i.e. base inode or 0
2152  * @base_ni:	[IN]  open base inode if allocating an extent mft record or NULL
2153  * @mrec:	[OUT] on successful return this is the mapped mft record
2154  *
2155  * Allocate an mft record in $MFT/$DATA of an open ntfs volume @vol.
2156  *
2157  * If @base_ni is NULL make the mft record a base mft record, i.e. a file or
2158  * direvctory inode, and allocate it at the default allocator position.  In
2159  * this case @mode is the file mode as given to us by the caller.  We in
2160  * particular use @mode to distinguish whether a file or a directory is being
2161  * created (S_IFDIR(mode) and S_IFREG(mode), respectively).
2162  *
2163  * If @base_ni is not NULL make the allocated mft record an extent record,
2164  * allocate it starting at the mft record after the base mft record and attach
2165  * the allocated and opened ntfs inode to the base inode @base_ni.  In this
2166  * case @mode must be 0 as it is meaningless for extent inodes.
2167  *
2168  * You need to check the return value with IS_ERR().  If false, the function
2169  * was successful and the return value is the now opened ntfs inode of the
2170  * allocated mft record.  *@mrec is then set to the allocated, mapped, pinned,
2171  * and locked mft record.  If IS_ERR() is true, the function failed and the
2172  * error code is obtained from PTR_ERR(return value).  *@mrec is undefined in
2173  * this case.
2174  *
2175  * Allocation strategy:
2176  *
2177  * To find a free mft record, we scan the mft bitmap for a zero bit.  To
2178  * optimize this we start scanning at the place specified by @base_ni or if
2179  * @base_ni is NULL we start where we last stopped and we perform wrap around
2180  * when we reach the end.  Note, we do not try to allocate mft records below
2181  * number 24 because numbers 0 to 15 are the defined system files anyway and 16
2182  * to 24 are special in that they are used for storing extension mft records
2183  * for the $DATA attribute of $MFT.  This is required to avoid the possibility
2184  * of creating a runlist with a circular dependency which once written to disk
2185  * can never be read in again.  Windows will only use records 16 to 24 for
2186  * normal files if the volume is completely out of space.  We never use them
2187  * which means that when the volume is really out of space we cannot create any
2188  * more files while Windows can still create up to 8 small files.  We can start
2189  * doing this at some later time, it does not matter much for now.
2190  *
2191  * When scanning the mft bitmap, we only search up to the last allocated mft
2192  * record.  If there are no free records left in the range 24 to number of
2193  * allocated mft records, then we extend the $MFT/$DATA attribute in order to
2194  * create free mft records.  We extend the allocated size of $MFT/$DATA by 16
2195  * records at a time or one cluster, if cluster size is above 16kiB.  If there
2196  * is not sufficient space to do this, we try to extend by a single mft record
2197  * or one cluster, if cluster size is above the mft record size.
2198  *
2199  * No matter how many mft records we allocate, we initialize only the first
2200  * allocated mft record, incrementing mft data size and initialized size
2201  * accordingly, open an ntfs_inode for it and return it to the caller, unless
2202  * there are less than 24 mft records, in which case we allocate and initialize
2203  * mft records until we reach record 24 which we consider as the first free mft
2204  * record for use by normal files.
2205  *
2206  * If during any stage we overflow the initialized data in the mft bitmap, we
2207  * extend the initialized size (and data size) by 8 bytes, allocating another
2208  * cluster if required.  The bitmap data size has to be at least equal to the
2209  * number of mft records in the mft, but it can be bigger, in which case the
2210  * superflous bits are padded with zeroes.
2211  *
2212  * Thus, when we return successfully (IS_ERR() is false), we will have:
2213  *	- initialized / extended the mft bitmap if necessary,
2214  *	- initialized / extended the mft data if necessary,
2215  *	- set the bit corresponding to the mft record being allocated in the
2216  *	  mft bitmap,
2217  *	- opened an ntfs_inode for the allocated mft record, and we will have
2218  *	- returned the ntfs_inode as well as the allocated mapped, pinned, and
2219  *	  locked mft record.
2220  *
2221  * On error, the volume will be left in a consistent state and no record will
2222  * be allocated.  If rolling back a partial operation fails, we may leave some
2223  * inconsistent metadata in which case we set NVolErrors() so the volume is
2224  * left dirty when unmounted.
2225  *
2226  * Note, this function cannot make use of most of the normal functions, like
2227  * for example for attribute resizing, etc, because when the run list overflows
2228  * the base mft record and an attribute list is used, it is very important that
2229  * the extension mft records used to store the $DATA attribute of $MFT can be
2230  * reached without having to read the information contained inside them, as
2231  * this would make it impossible to find them in the first place after the
2232  * volume is unmounted.  $MFT/$BITMAP probably does not need to follow this
2233  * rule because the bitmap is not essential for finding the mft records, but on
2234  * the other hand, handling the bitmap in this special way would make life
2235  * easier because otherwise there might be circular invocations of functions
2236  * when reading the bitmap.
2237  */
ntfs_mft_record_alloc(ntfs_volume * vol,const int mode,ntfs_inode * base_ni,MFT_RECORD ** mrec)2238 ntfs_inode *ntfs_mft_record_alloc(ntfs_volume *vol, const int mode,
2239 		ntfs_inode *base_ni, MFT_RECORD **mrec)
2240 {
2241 	s64 ll, bit, old_data_initialized, old_data_size;
2242 	unsigned long flags;
2243 	struct inode *vi;
2244 	struct page *page;
2245 	ntfs_inode *mft_ni, *mftbmp_ni, *ni;
2246 	ntfs_attr_search_ctx *ctx;
2247 	MFT_RECORD *m;
2248 	ATTR_RECORD *a;
2249 	pgoff_t index;
2250 	unsigned int ofs;
2251 	int err;
2252 	le16 seq_no, usn;
2253 	bool record_formatted = false;
2254 
2255 	if (base_ni) {
2256 		ntfs_debug("Entering (allocating an extent mft record for "
2257 				"base mft record 0x%llx).",
2258 				(long long)base_ni->mft_no);
2259 		/* @mode and @base_ni are mutually exclusive. */
2260 		BUG_ON(mode);
2261 	} else
2262 		ntfs_debug("Entering (allocating a base mft record).");
2263 	if (mode) {
2264 		/* @mode and @base_ni are mutually exclusive. */
2265 		BUG_ON(base_ni);
2266 		/* We only support creation of normal files and directories. */
2267 		if (!S_ISREG(mode) && !S_ISDIR(mode))
2268 			return ERR_PTR(-EOPNOTSUPP);
2269 	}
2270 	BUG_ON(!mrec);
2271 	mft_ni = NTFS_I(vol->mft_ino);
2272 	mftbmp_ni = NTFS_I(vol->mftbmp_ino);
2273 	down_write(&vol->mftbmp_lock);
2274 	bit = ntfs_mft_bitmap_find_and_alloc_free_rec_nolock(vol, base_ni);
2275 	if (bit >= 0) {
2276 		ntfs_debug("Found and allocated free record (#1), bit 0x%llx.",
2277 				(long long)bit);
2278 		goto have_alloc_rec;
2279 	}
2280 	if (bit != -ENOSPC) {
2281 		up_write(&vol->mftbmp_lock);
2282 		return ERR_PTR(bit);
2283 	}
2284 	/*
2285 	 * No free mft records left.  If the mft bitmap already covers more
2286 	 * than the currently used mft records, the next records are all free,
2287 	 * so we can simply allocate the first unused mft record.
2288 	 * Note: We also have to make sure that the mft bitmap at least covers
2289 	 * the first 24 mft records as they are special and whilst they may not
2290 	 * be in use, we do not allocate from them.
2291 	 */
2292 	read_lock_irqsave(&mft_ni->size_lock, flags);
2293 	ll = mft_ni->initialized_size >> vol->mft_record_size_bits;
2294 	read_unlock_irqrestore(&mft_ni->size_lock, flags);
2295 	read_lock_irqsave(&mftbmp_ni->size_lock, flags);
2296 	old_data_initialized = mftbmp_ni->initialized_size;
2297 	read_unlock_irqrestore(&mftbmp_ni->size_lock, flags);
2298 	if (old_data_initialized << 3 > ll && old_data_initialized > 3) {
2299 		bit = ll;
2300 		if (bit < 24)
2301 			bit = 24;
2302 		if (unlikely(bit >= (1ll << 32)))
2303 			goto max_err_out;
2304 		ntfs_debug("Found free record (#2), bit 0x%llx.",
2305 				(long long)bit);
2306 		goto found_free_rec;
2307 	}
2308 	/*
2309 	 * The mft bitmap needs to be expanded until it covers the first unused
2310 	 * mft record that we can allocate.
2311 	 * Note: The smallest mft record we allocate is mft record 24.
2312 	 */
2313 	bit = old_data_initialized << 3;
2314 	if (unlikely(bit >= (1ll << 32)))
2315 		goto max_err_out;
2316 	read_lock_irqsave(&mftbmp_ni->size_lock, flags);
2317 	old_data_size = mftbmp_ni->allocated_size;
2318 	ntfs_debug("Status of mftbmp before extension: allocated_size 0x%llx, "
2319 			"data_size 0x%llx, initialized_size 0x%llx.",
2320 			(long long)old_data_size,
2321 			(long long)i_size_read(vol->mftbmp_ino),
2322 			(long long)old_data_initialized);
2323 	read_unlock_irqrestore(&mftbmp_ni->size_lock, flags);
2324 	if (old_data_initialized + 8 > old_data_size) {
2325 		/* Need to extend bitmap by one more cluster. */
2326 		ntfs_debug("mftbmp: initialized_size + 8 > allocated_size.");
2327 		err = ntfs_mft_bitmap_extend_allocation_nolock(vol);
2328 		if (unlikely(err)) {
2329 			up_write(&vol->mftbmp_lock);
2330 			goto err_out;
2331 		}
2332 #ifdef DEBUG
2333 		read_lock_irqsave(&mftbmp_ni->size_lock, flags);
2334 		ntfs_debug("Status of mftbmp after allocation extension: "
2335 				"allocated_size 0x%llx, data_size 0x%llx, "
2336 				"initialized_size 0x%llx.",
2337 				(long long)mftbmp_ni->allocated_size,
2338 				(long long)i_size_read(vol->mftbmp_ino),
2339 				(long long)mftbmp_ni->initialized_size);
2340 		read_unlock_irqrestore(&mftbmp_ni->size_lock, flags);
2341 #endif /* DEBUG */
2342 	}
2343 	/*
2344 	 * We now have sufficient allocated space, extend the initialized_size
2345 	 * as well as the data_size if necessary and fill the new space with
2346 	 * zeroes.
2347 	 */
2348 	err = ntfs_mft_bitmap_extend_initialized_nolock(vol);
2349 	if (unlikely(err)) {
2350 		up_write(&vol->mftbmp_lock);
2351 		goto err_out;
2352 	}
2353 #ifdef DEBUG
2354 	read_lock_irqsave(&mftbmp_ni->size_lock, flags);
2355 	ntfs_debug("Status of mftbmp after initialized extension: "
2356 			"allocated_size 0x%llx, data_size 0x%llx, "
2357 			"initialized_size 0x%llx.",
2358 			(long long)mftbmp_ni->allocated_size,
2359 			(long long)i_size_read(vol->mftbmp_ino),
2360 			(long long)mftbmp_ni->initialized_size);
2361 	read_unlock_irqrestore(&mftbmp_ni->size_lock, flags);
2362 #endif /* DEBUG */
2363 	ntfs_debug("Found free record (#3), bit 0x%llx.", (long long)bit);
2364 found_free_rec:
2365 	/* @bit is the found free mft record, allocate it in the mft bitmap. */
2366 	ntfs_debug("At found_free_rec.");
2367 	err = ntfs_bitmap_set_bit(vol->mftbmp_ino, bit);
2368 	if (unlikely(err)) {
2369 		ntfs_error(vol->sb, "Failed to allocate bit in mft bitmap.");
2370 		up_write(&vol->mftbmp_lock);
2371 		goto err_out;
2372 	}
2373 	ntfs_debug("Set bit 0x%llx in mft bitmap.", (long long)bit);
2374 have_alloc_rec:
2375 	/*
2376 	 * The mft bitmap is now uptodate.  Deal with mft data attribute now.
2377 	 * Note, we keep hold of the mft bitmap lock for writing until all
2378 	 * modifications to the mft data attribute are complete, too, as they
2379 	 * will impact decisions for mft bitmap and mft record allocation done
2380 	 * by a parallel allocation and if the lock is not maintained a
2381 	 * parallel allocation could allocate the same mft record as this one.
2382 	 */
2383 	ll = (bit + 1) << vol->mft_record_size_bits;
2384 	read_lock_irqsave(&mft_ni->size_lock, flags);
2385 	old_data_initialized = mft_ni->initialized_size;
2386 	read_unlock_irqrestore(&mft_ni->size_lock, flags);
2387 	if (ll <= old_data_initialized) {
2388 		ntfs_debug("Allocated mft record already initialized.");
2389 		goto mft_rec_already_initialized;
2390 	}
2391 	ntfs_debug("Initializing allocated mft record.");
2392 	/*
2393 	 * The mft record is outside the initialized data.  Extend the mft data
2394 	 * attribute until it covers the allocated record.  The loop is only
2395 	 * actually traversed more than once when a freshly formatted volume is
2396 	 * first written to so it optimizes away nicely in the common case.
2397 	 */
2398 	read_lock_irqsave(&mft_ni->size_lock, flags);
2399 	ntfs_debug("Status of mft data before extension: "
2400 			"allocated_size 0x%llx, data_size 0x%llx, "
2401 			"initialized_size 0x%llx.",
2402 			(long long)mft_ni->allocated_size,
2403 			(long long)i_size_read(vol->mft_ino),
2404 			(long long)mft_ni->initialized_size);
2405 	while (ll > mft_ni->allocated_size) {
2406 		read_unlock_irqrestore(&mft_ni->size_lock, flags);
2407 		err = ntfs_mft_data_extend_allocation_nolock(vol);
2408 		if (unlikely(err)) {
2409 			ntfs_error(vol->sb, "Failed to extend mft data "
2410 					"allocation.");
2411 			goto undo_mftbmp_alloc_nolock;
2412 		}
2413 		read_lock_irqsave(&mft_ni->size_lock, flags);
2414 		ntfs_debug("Status of mft data after allocation extension: "
2415 				"allocated_size 0x%llx, data_size 0x%llx, "
2416 				"initialized_size 0x%llx.",
2417 				(long long)mft_ni->allocated_size,
2418 				(long long)i_size_read(vol->mft_ino),
2419 				(long long)mft_ni->initialized_size);
2420 	}
2421 	read_unlock_irqrestore(&mft_ni->size_lock, flags);
2422 	/*
2423 	 * Extend mft data initialized size (and data size of course) to reach
2424 	 * the allocated mft record, formatting the mft records allong the way.
2425 	 * Note: We only modify the ntfs_inode structure as that is all that is
2426 	 * needed by ntfs_mft_record_format().  We will update the attribute
2427 	 * record itself in one fell swoop later on.
2428 	 */
2429 	write_lock_irqsave(&mft_ni->size_lock, flags);
2430 	old_data_initialized = mft_ni->initialized_size;
2431 	old_data_size = vol->mft_ino->i_size;
2432 	while (ll > mft_ni->initialized_size) {
2433 		s64 new_initialized_size, mft_no;
2434 
2435 		new_initialized_size = mft_ni->initialized_size +
2436 				vol->mft_record_size;
2437 		mft_no = mft_ni->initialized_size >> vol->mft_record_size_bits;
2438 		if (new_initialized_size > i_size_read(vol->mft_ino))
2439 			i_size_write(vol->mft_ino, new_initialized_size);
2440 		write_unlock_irqrestore(&mft_ni->size_lock, flags);
2441 		ntfs_debug("Initializing mft record 0x%llx.",
2442 				(long long)mft_no);
2443 		err = ntfs_mft_record_format(vol, mft_no);
2444 		if (unlikely(err)) {
2445 			ntfs_error(vol->sb, "Failed to format mft record.");
2446 			goto undo_data_init;
2447 		}
2448 		write_lock_irqsave(&mft_ni->size_lock, flags);
2449 		mft_ni->initialized_size = new_initialized_size;
2450 	}
2451 	write_unlock_irqrestore(&mft_ni->size_lock, flags);
2452 	record_formatted = true;
2453 	/* Update the mft data attribute record to reflect the new sizes. */
2454 	m = map_mft_record(mft_ni);
2455 	if (IS_ERR(m)) {
2456 		ntfs_error(vol->sb, "Failed to map mft record.");
2457 		err = PTR_ERR(m);
2458 		goto undo_data_init;
2459 	}
2460 	ctx = ntfs_attr_get_search_ctx(mft_ni, m);
2461 	if (unlikely(!ctx)) {
2462 		ntfs_error(vol->sb, "Failed to get search context.");
2463 		err = -ENOMEM;
2464 		unmap_mft_record(mft_ni);
2465 		goto undo_data_init;
2466 	}
2467 	err = ntfs_attr_lookup(mft_ni->type, mft_ni->name, mft_ni->name_len,
2468 			CASE_SENSITIVE, 0, NULL, 0, ctx);
2469 	if (unlikely(err)) {
2470 		ntfs_error(vol->sb, "Failed to find first attribute extent of "
2471 				"mft data attribute.");
2472 		ntfs_attr_put_search_ctx(ctx);
2473 		unmap_mft_record(mft_ni);
2474 		goto undo_data_init;
2475 	}
2476 	a = ctx->attr;
2477 	read_lock_irqsave(&mft_ni->size_lock, flags);
2478 	a->data.non_resident.initialized_size =
2479 			cpu_to_sle64(mft_ni->initialized_size);
2480 	a->data.non_resident.data_size =
2481 			cpu_to_sle64(i_size_read(vol->mft_ino));
2482 	read_unlock_irqrestore(&mft_ni->size_lock, flags);
2483 	/* Ensure the changes make it to disk. */
2484 	flush_dcache_mft_record_page(ctx->ntfs_ino);
2485 	mark_mft_record_dirty(ctx->ntfs_ino);
2486 	ntfs_attr_put_search_ctx(ctx);
2487 	unmap_mft_record(mft_ni);
2488 	read_lock_irqsave(&mft_ni->size_lock, flags);
2489 	ntfs_debug("Status of mft data after mft record initialization: "
2490 			"allocated_size 0x%llx, data_size 0x%llx, "
2491 			"initialized_size 0x%llx.",
2492 			(long long)mft_ni->allocated_size,
2493 			(long long)i_size_read(vol->mft_ino),
2494 			(long long)mft_ni->initialized_size);
2495 	BUG_ON(i_size_read(vol->mft_ino) > mft_ni->allocated_size);
2496 	BUG_ON(mft_ni->initialized_size > i_size_read(vol->mft_ino));
2497 	read_unlock_irqrestore(&mft_ni->size_lock, flags);
2498 mft_rec_already_initialized:
2499 	/*
2500 	 * We can finally drop the mft bitmap lock as the mft data attribute
2501 	 * has been fully updated.  The only disparity left is that the
2502 	 * allocated mft record still needs to be marked as in use to match the
2503 	 * set bit in the mft bitmap but this is actually not a problem since
2504 	 * this mft record is not referenced from anywhere yet and the fact
2505 	 * that it is allocated in the mft bitmap means that no-one will try to
2506 	 * allocate it either.
2507 	 */
2508 	up_write(&vol->mftbmp_lock);
2509 	/*
2510 	 * We now have allocated and initialized the mft record.  Calculate the
2511 	 * index of and the offset within the page cache page the record is in.
2512 	 */
2513 	index = bit << vol->mft_record_size_bits >> PAGE_SHIFT;
2514 	ofs = (bit << vol->mft_record_size_bits) & ~PAGE_MASK;
2515 	/* Read, map, and pin the page containing the mft record. */
2516 	page = ntfs_map_page(vol->mft_ino->i_mapping, index);
2517 	if (IS_ERR(page)) {
2518 		ntfs_error(vol->sb, "Failed to map page containing allocated "
2519 				"mft record 0x%llx.", (long long)bit);
2520 		err = PTR_ERR(page);
2521 		goto undo_mftbmp_alloc;
2522 	}
2523 	lock_page(page);
2524 	BUG_ON(!PageUptodate(page));
2525 	ClearPageUptodate(page);
2526 	m = (MFT_RECORD*)((u8*)page_address(page) + ofs);
2527 	/* If we just formatted the mft record no need to do it again. */
2528 	if (!record_formatted) {
2529 		/* Sanity check that the mft record is really not in use. */
2530 		if (ntfs_is_file_record(m->magic) &&
2531 				(m->flags & MFT_RECORD_IN_USE)) {
2532 			ntfs_error(vol->sb, "Mft record 0x%llx was marked "
2533 					"free in mft bitmap but is marked "
2534 					"used itself.  Corrupt filesystem.  "
2535 					"Unmount and run chkdsk.",
2536 					(long long)bit);
2537 			err = -EIO;
2538 			SetPageUptodate(page);
2539 			unlock_page(page);
2540 			ntfs_unmap_page(page);
2541 			NVolSetErrors(vol);
2542 			goto undo_mftbmp_alloc;
2543 		}
2544 		/*
2545 		 * We need to (re-)format the mft record, preserving the
2546 		 * sequence number if it is not zero as well as the update
2547 		 * sequence number if it is not zero or -1 (0xffff).  This
2548 		 * means we do not need to care whether or not something went
2549 		 * wrong with the previous mft record.
2550 		 */
2551 		seq_no = m->sequence_number;
2552 		usn = *(le16*)((u8*)m + le16_to_cpu(m->usa_ofs));
2553 		err = ntfs_mft_record_layout(vol, bit, m);
2554 		if (unlikely(err)) {
2555 			ntfs_error(vol->sb, "Failed to layout allocated mft "
2556 					"record 0x%llx.", (long long)bit);
2557 			SetPageUptodate(page);
2558 			unlock_page(page);
2559 			ntfs_unmap_page(page);
2560 			goto undo_mftbmp_alloc;
2561 		}
2562 		if (seq_no)
2563 			m->sequence_number = seq_no;
2564 		if (usn && le16_to_cpu(usn) != 0xffff)
2565 			*(le16*)((u8*)m + le16_to_cpu(m->usa_ofs)) = usn;
2566 	}
2567 	/* Set the mft record itself in use. */
2568 	m->flags |= MFT_RECORD_IN_USE;
2569 	if (S_ISDIR(mode))
2570 		m->flags |= MFT_RECORD_IS_DIRECTORY;
2571 	flush_dcache_page(page);
2572 	SetPageUptodate(page);
2573 	if (base_ni) {
2574 		MFT_RECORD *m_tmp;
2575 
2576 		/*
2577 		 * Setup the base mft record in the extent mft record.  This
2578 		 * completes initialization of the allocated extent mft record
2579 		 * and we can simply use it with map_extent_mft_record().
2580 		 */
2581 		m->base_mft_record = MK_LE_MREF(base_ni->mft_no,
2582 				base_ni->seq_no);
2583 		/*
2584 		 * Allocate an extent inode structure for the new mft record,
2585 		 * attach it to the base inode @base_ni and map, pin, and lock
2586 		 * its, i.e. the allocated, mft record.
2587 		 */
2588 		m_tmp = map_extent_mft_record(base_ni, bit, &ni);
2589 		if (IS_ERR(m_tmp)) {
2590 			ntfs_error(vol->sb, "Failed to map allocated extent "
2591 					"mft record 0x%llx.", (long long)bit);
2592 			err = PTR_ERR(m_tmp);
2593 			/* Set the mft record itself not in use. */
2594 			m->flags &= cpu_to_le16(
2595 					~le16_to_cpu(MFT_RECORD_IN_USE));
2596 			flush_dcache_page(page);
2597 			/* Make sure the mft record is written out to disk. */
2598 			mark_ntfs_record_dirty(page, ofs);
2599 			unlock_page(page);
2600 			ntfs_unmap_page(page);
2601 			goto undo_mftbmp_alloc;
2602 		}
2603 		BUG_ON(m != m_tmp);
2604 		/*
2605 		 * Make sure the allocated mft record is written out to disk.
2606 		 * No need to set the inode dirty because the caller is going
2607 		 * to do that anyway after finishing with the new extent mft
2608 		 * record (e.g. at a minimum a new attribute will be added to
2609 		 * the mft record.
2610 		 */
2611 		mark_ntfs_record_dirty(page, ofs);
2612 		unlock_page(page);
2613 		/*
2614 		 * Need to unmap the page since map_extent_mft_record() mapped
2615 		 * it as well so we have it mapped twice at the moment.
2616 		 */
2617 		ntfs_unmap_page(page);
2618 	} else {
2619 		/*
2620 		 * Allocate a new VFS inode and set it up.  NOTE: @vi->i_nlink
2621 		 * is set to 1 but the mft record->link_count is 0.  The caller
2622 		 * needs to bear this in mind.
2623 		 */
2624 		vi = new_inode(vol->sb);
2625 		if (unlikely(!vi)) {
2626 			err = -ENOMEM;
2627 			/* Set the mft record itself not in use. */
2628 			m->flags &= cpu_to_le16(
2629 					~le16_to_cpu(MFT_RECORD_IN_USE));
2630 			flush_dcache_page(page);
2631 			/* Make sure the mft record is written out to disk. */
2632 			mark_ntfs_record_dirty(page, ofs);
2633 			unlock_page(page);
2634 			ntfs_unmap_page(page);
2635 			goto undo_mftbmp_alloc;
2636 		}
2637 		vi->i_ino = bit;
2638 
2639 		/* The owner and group come from the ntfs volume. */
2640 		vi->i_uid = vol->uid;
2641 		vi->i_gid = vol->gid;
2642 
2643 		/* Initialize the ntfs specific part of @vi. */
2644 		ntfs_init_big_inode(vi);
2645 		ni = NTFS_I(vi);
2646 		/*
2647 		 * Set the appropriate mode, attribute type, and name.  For
2648 		 * directories, also setup the index values to the defaults.
2649 		 */
2650 		if (S_ISDIR(mode)) {
2651 			vi->i_mode = S_IFDIR | S_IRWXUGO;
2652 			vi->i_mode &= ~vol->dmask;
2653 
2654 			NInoSetMstProtected(ni);
2655 			ni->type = AT_INDEX_ALLOCATION;
2656 			ni->name = I30;
2657 			ni->name_len = 4;
2658 
2659 			ni->itype.index.block_size = 4096;
2660 			ni->itype.index.block_size_bits = ntfs_ffs(4096) - 1;
2661 			ni->itype.index.collation_rule = COLLATION_FILE_NAME;
2662 			if (vol->cluster_size <= ni->itype.index.block_size) {
2663 				ni->itype.index.vcn_size = vol->cluster_size;
2664 				ni->itype.index.vcn_size_bits =
2665 						vol->cluster_size_bits;
2666 			} else {
2667 				ni->itype.index.vcn_size = vol->sector_size;
2668 				ni->itype.index.vcn_size_bits =
2669 						vol->sector_size_bits;
2670 			}
2671 		} else {
2672 			vi->i_mode = S_IFREG | S_IRWXUGO;
2673 			vi->i_mode &= ~vol->fmask;
2674 
2675 			ni->type = AT_DATA;
2676 			ni->name = NULL;
2677 			ni->name_len = 0;
2678 		}
2679 		if (IS_RDONLY(vi))
2680 			vi->i_mode &= ~S_IWUGO;
2681 
2682 		/* Set the inode times to the current time. */
2683 		vi->i_atime = vi->i_mtime = vi->i_ctime =
2684 			current_time(vi);
2685 		/*
2686 		 * Set the file size to 0, the ntfs inode sizes are set to 0 by
2687 		 * the call to ntfs_init_big_inode() below.
2688 		 */
2689 		vi->i_size = 0;
2690 		vi->i_blocks = 0;
2691 
2692 		/* Set the sequence number. */
2693 		vi->i_generation = ni->seq_no = le16_to_cpu(m->sequence_number);
2694 		/*
2695 		 * Manually map, pin, and lock the mft record as we already
2696 		 * have its page mapped and it is very easy to do.
2697 		 */
2698 		atomic_inc(&ni->count);
2699 		mutex_lock(&ni->mrec_lock);
2700 		ni->page = page;
2701 		ni->page_ofs = ofs;
2702 		/*
2703 		 * Make sure the allocated mft record is written out to disk.
2704 		 * NOTE: We do not set the ntfs inode dirty because this would
2705 		 * fail in ntfs_write_inode() because the inode does not have a
2706 		 * standard information attribute yet.  Also, there is no need
2707 		 * to set the inode dirty because the caller is going to do
2708 		 * that anyway after finishing with the new mft record (e.g. at
2709 		 * a minimum some new attributes will be added to the mft
2710 		 * record.
2711 		 */
2712 		mark_ntfs_record_dirty(page, ofs);
2713 		unlock_page(page);
2714 
2715 		/* Add the inode to the inode hash for the superblock. */
2716 		insert_inode_hash(vi);
2717 
2718 		/* Update the default mft allocation position. */
2719 		vol->mft_data_pos = bit + 1;
2720 	}
2721 	/*
2722 	 * Return the opened, allocated inode of the allocated mft record as
2723 	 * well as the mapped, pinned, and locked mft record.
2724 	 */
2725 	ntfs_debug("Returning opened, allocated %sinode 0x%llx.",
2726 			base_ni ? "extent " : "", (long long)bit);
2727 	*mrec = m;
2728 	return ni;
2729 undo_data_init:
2730 	write_lock_irqsave(&mft_ni->size_lock, flags);
2731 	mft_ni->initialized_size = old_data_initialized;
2732 	i_size_write(vol->mft_ino, old_data_size);
2733 	write_unlock_irqrestore(&mft_ni->size_lock, flags);
2734 	goto undo_mftbmp_alloc_nolock;
2735 undo_mftbmp_alloc:
2736 	down_write(&vol->mftbmp_lock);
2737 undo_mftbmp_alloc_nolock:
2738 	if (ntfs_bitmap_clear_bit(vol->mftbmp_ino, bit)) {
2739 		ntfs_error(vol->sb, "Failed to clear bit in mft bitmap.%s", es);
2740 		NVolSetErrors(vol);
2741 	}
2742 	up_write(&vol->mftbmp_lock);
2743 err_out:
2744 	return ERR_PTR(err);
2745 max_err_out:
2746 	ntfs_warning(vol->sb, "Cannot allocate mft record because the maximum "
2747 			"number of inodes (2^32) has already been reached.");
2748 	up_write(&vol->mftbmp_lock);
2749 	return ERR_PTR(-ENOSPC);
2750 }
2751 
2752 /**
2753  * ntfs_extent_mft_record_free - free an extent mft record on an ntfs volume
2754  * @ni:		ntfs inode of the mapped extent mft record to free
2755  * @m:		mapped extent mft record of the ntfs inode @ni
2756  *
2757  * Free the mapped extent mft record @m of the extent ntfs inode @ni.
2758  *
2759  * Note that this function unmaps the mft record and closes and destroys @ni
2760  * internally and hence you cannot use either @ni nor @m any more after this
2761  * function returns success.
2762  *
2763  * On success return 0 and on error return -errno.  @ni and @m are still valid
2764  * in this case and have not been freed.
2765  *
2766  * For some errors an error message is displayed and the success code 0 is
2767  * returned and the volume is then left dirty on umount.  This makes sense in
2768  * case we could not rollback the changes that were already done since the
2769  * caller no longer wants to reference this mft record so it does not matter to
2770  * the caller if something is wrong with it as long as it is properly detached
2771  * from the base inode.
2772  */
ntfs_extent_mft_record_free(ntfs_inode * ni,MFT_RECORD * m)2773 int ntfs_extent_mft_record_free(ntfs_inode *ni, MFT_RECORD *m)
2774 {
2775 	unsigned long mft_no = ni->mft_no;
2776 	ntfs_volume *vol = ni->vol;
2777 	ntfs_inode *base_ni;
2778 	ntfs_inode **extent_nis;
2779 	int i, err;
2780 	le16 old_seq_no;
2781 	u16 seq_no;
2782 
2783 	BUG_ON(NInoAttr(ni));
2784 	BUG_ON(ni->nr_extents != -1);
2785 
2786 	mutex_lock(&ni->extent_lock);
2787 	base_ni = ni->ext.base_ntfs_ino;
2788 	mutex_unlock(&ni->extent_lock);
2789 
2790 	BUG_ON(base_ni->nr_extents <= 0);
2791 
2792 	ntfs_debug("Entering for extent inode 0x%lx, base inode 0x%lx.\n",
2793 			mft_no, base_ni->mft_no);
2794 
2795 	mutex_lock(&base_ni->extent_lock);
2796 
2797 	/* Make sure we are holding the only reference to the extent inode. */
2798 	if (atomic_read(&ni->count) > 2) {
2799 		ntfs_error(vol->sb, "Tried to free busy extent inode 0x%lx, "
2800 				"not freeing.", base_ni->mft_no);
2801 		mutex_unlock(&base_ni->extent_lock);
2802 		return -EBUSY;
2803 	}
2804 
2805 	/* Dissociate the ntfs inode from the base inode. */
2806 	extent_nis = base_ni->ext.extent_ntfs_inos;
2807 	err = -ENOENT;
2808 	for (i = 0; i < base_ni->nr_extents; i++) {
2809 		if (ni != extent_nis[i])
2810 			continue;
2811 		extent_nis += i;
2812 		base_ni->nr_extents--;
2813 		memmove(extent_nis, extent_nis + 1, (base_ni->nr_extents - i) *
2814 				sizeof(ntfs_inode*));
2815 		err = 0;
2816 		break;
2817 	}
2818 
2819 	mutex_unlock(&base_ni->extent_lock);
2820 
2821 	if (unlikely(err)) {
2822 		ntfs_error(vol->sb, "Extent inode 0x%lx is not attached to "
2823 				"its base inode 0x%lx.", mft_no,
2824 				base_ni->mft_no);
2825 		BUG();
2826 	}
2827 
2828 	/*
2829 	 * The extent inode is no longer attached to the base inode so no one
2830 	 * can get a reference to it any more.
2831 	 */
2832 
2833 	/* Mark the mft record as not in use. */
2834 	m->flags &= ~MFT_RECORD_IN_USE;
2835 
2836 	/* Increment the sequence number, skipping zero, if it is not zero. */
2837 	old_seq_no = m->sequence_number;
2838 	seq_no = le16_to_cpu(old_seq_no);
2839 	if (seq_no == 0xffff)
2840 		seq_no = 1;
2841 	else if (seq_no)
2842 		seq_no++;
2843 	m->sequence_number = cpu_to_le16(seq_no);
2844 
2845 	/*
2846 	 * Set the ntfs inode dirty and write it out.  We do not need to worry
2847 	 * about the base inode here since whatever caused the extent mft
2848 	 * record to be freed is guaranteed to do it already.
2849 	 */
2850 	NInoSetDirty(ni);
2851 	err = write_mft_record(ni, m, 0);
2852 	if (unlikely(err)) {
2853 		ntfs_error(vol->sb, "Failed to write mft record 0x%lx, not "
2854 				"freeing.", mft_no);
2855 		goto rollback;
2856 	}
2857 rollback_error:
2858 	/* Unmap and throw away the now freed extent inode. */
2859 	unmap_extent_mft_record(ni);
2860 	ntfs_clear_extent_inode(ni);
2861 
2862 	/* Clear the bit in the $MFT/$BITMAP corresponding to this record. */
2863 	down_write(&vol->mftbmp_lock);
2864 	err = ntfs_bitmap_clear_bit(vol->mftbmp_ino, mft_no);
2865 	up_write(&vol->mftbmp_lock);
2866 	if (unlikely(err)) {
2867 		/*
2868 		 * The extent inode is gone but we failed to deallocate it in
2869 		 * the mft bitmap.  Just emit a warning and leave the volume
2870 		 * dirty on umount.
2871 		 */
2872 		ntfs_error(vol->sb, "Failed to clear bit in mft bitmap.%s", es);
2873 		NVolSetErrors(vol);
2874 	}
2875 	return 0;
2876 rollback:
2877 	/* Rollback what we did... */
2878 	mutex_lock(&base_ni->extent_lock);
2879 	extent_nis = base_ni->ext.extent_ntfs_inos;
2880 	if (!(base_ni->nr_extents & 3)) {
2881 		int new_size = (base_ni->nr_extents + 4) * sizeof(ntfs_inode*);
2882 
2883 		extent_nis = kmalloc(new_size, GFP_NOFS);
2884 		if (unlikely(!extent_nis)) {
2885 			ntfs_error(vol->sb, "Failed to allocate internal "
2886 					"buffer during rollback.%s", es);
2887 			mutex_unlock(&base_ni->extent_lock);
2888 			NVolSetErrors(vol);
2889 			goto rollback_error;
2890 		}
2891 		if (base_ni->nr_extents) {
2892 			BUG_ON(!base_ni->ext.extent_ntfs_inos);
2893 			memcpy(extent_nis, base_ni->ext.extent_ntfs_inos,
2894 					new_size - 4 * sizeof(ntfs_inode*));
2895 			kfree(base_ni->ext.extent_ntfs_inos);
2896 		}
2897 		base_ni->ext.extent_ntfs_inos = extent_nis;
2898 	}
2899 	m->flags |= MFT_RECORD_IN_USE;
2900 	m->sequence_number = old_seq_no;
2901 	extent_nis[base_ni->nr_extents++] = ni;
2902 	mutex_unlock(&base_ni->extent_lock);
2903 	mark_mft_record_dirty(ni);
2904 	return err;
2905 }
2906 #endif /* NTFS_RW */
2907