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d475c634 MW |
1 | /* |
2 | * fs/dax.c - Direct Access filesystem code | |
3 | * Copyright (c) 2013-2014 Intel Corporation | |
4 | * Author: Matthew Wilcox <matthew.r.wilcox@intel.com> | |
5 | * Author: Ross Zwisler <ross.zwisler@linux.intel.com> | |
6 | * | |
7 | * This program is free software; you can redistribute it and/or modify it | |
8 | * under the terms and conditions of the GNU General Public License, | |
9 | * version 2, as published by the Free Software Foundation. | |
10 | * | |
11 | * This program is distributed in the hope it will be useful, but WITHOUT | |
12 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
13 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for | |
14 | * more details. | |
15 | */ | |
16 | ||
17 | #include <linux/atomic.h> | |
18 | #include <linux/blkdev.h> | |
19 | #include <linux/buffer_head.h> | |
d77e92e2 | 20 | #include <linux/dax.h> |
d475c634 MW |
21 | #include <linux/fs.h> |
22 | #include <linux/genhd.h> | |
f7ca90b1 MW |
23 | #include <linux/highmem.h> |
24 | #include <linux/memcontrol.h> | |
25 | #include <linux/mm.h> | |
d475c634 | 26 | #include <linux/mutex.h> |
9973c98e | 27 | #include <linux/pagevec.h> |
2765cfbb | 28 | #include <linux/pmem.h> |
289c6aed | 29 | #include <linux/sched.h> |
d475c634 | 30 | #include <linux/uio.h> |
f7ca90b1 | 31 | #include <linux/vmstat.h> |
34c0fd54 | 32 | #include <linux/pfn_t.h> |
0e749e54 | 33 | #include <linux/sizes.h> |
d475c634 | 34 | |
b2e0d162 DW |
35 | static long dax_map_atomic(struct block_device *bdev, struct blk_dax_ctl *dax) |
36 | { | |
37 | struct request_queue *q = bdev->bd_queue; | |
38 | long rc = -EIO; | |
39 | ||
40 | dax->addr = (void __pmem *) ERR_PTR(-EIO); | |
41 | if (blk_queue_enter(q, true) != 0) | |
42 | return rc; | |
43 | ||
44 | rc = bdev_direct_access(bdev, dax); | |
45 | if (rc < 0) { | |
46 | dax->addr = (void __pmem *) ERR_PTR(rc); | |
47 | blk_queue_exit(q); | |
48 | return rc; | |
49 | } | |
50 | return rc; | |
51 | } | |
52 | ||
53 | static void dax_unmap_atomic(struct block_device *bdev, | |
54 | const struct blk_dax_ctl *dax) | |
55 | { | |
56 | if (IS_ERR(dax->addr)) | |
57 | return; | |
58 | blk_queue_exit(bdev->bd_queue); | |
59 | } | |
60 | ||
d1a5f2b4 DW |
61 | struct page *read_dax_sector(struct block_device *bdev, sector_t n) |
62 | { | |
63 | struct page *page = alloc_pages(GFP_KERNEL, 0); | |
64 | struct blk_dax_ctl dax = { | |
65 | .size = PAGE_SIZE, | |
66 | .sector = n & ~((((int) PAGE_SIZE) / 512) - 1), | |
67 | }; | |
68 | long rc; | |
69 | ||
70 | if (!page) | |
71 | return ERR_PTR(-ENOMEM); | |
72 | ||
73 | rc = dax_map_atomic(bdev, &dax); | |
74 | if (rc < 0) | |
75 | return ERR_PTR(rc); | |
76 | memcpy_from_pmem(page_address(page), dax.addr, PAGE_SIZE); | |
77 | dax_unmap_atomic(bdev, &dax); | |
78 | return page; | |
79 | } | |
80 | ||
1ca19157 DC |
81 | /* |
82 | * dax_clear_blocks() is called from within transaction context from XFS, | |
83 | * and hence this means the stack from this point must follow GFP_NOFS | |
84 | * semantics for all operations. | |
85 | */ | |
b2e0d162 | 86 | int dax_clear_blocks(struct inode *inode, sector_t block, long _size) |
289c6aed MW |
87 | { |
88 | struct block_device *bdev = inode->i_sb->s_bdev; | |
b2e0d162 DW |
89 | struct blk_dax_ctl dax = { |
90 | .sector = block << (inode->i_blkbits - 9), | |
91 | .size = _size, | |
92 | }; | |
289c6aed MW |
93 | |
94 | might_sleep(); | |
95 | do { | |
0e749e54 | 96 | long count, sz; |
289c6aed | 97 | |
b2e0d162 | 98 | count = dax_map_atomic(bdev, &dax); |
289c6aed MW |
99 | if (count < 0) |
100 | return count; | |
0e749e54 | 101 | sz = min_t(long, count, SZ_128K); |
b2e0d162 DW |
102 | clear_pmem(dax.addr, sz); |
103 | dax.size -= sz; | |
104 | dax.sector += sz / 512; | |
105 | dax_unmap_atomic(bdev, &dax); | |
0e749e54 | 106 | cond_resched(); |
b2e0d162 | 107 | } while (dax.size); |
289c6aed | 108 | |
2765cfbb | 109 | wmb_pmem(); |
289c6aed MW |
110 | return 0; |
111 | } | |
112 | EXPORT_SYMBOL_GPL(dax_clear_blocks); | |
113 | ||
2765cfbb | 114 | /* the clear_pmem() calls are ordered by a wmb_pmem() in the caller */ |
e2e05394 RZ |
115 | static void dax_new_buf(void __pmem *addr, unsigned size, unsigned first, |
116 | loff_t pos, loff_t end) | |
d475c634 MW |
117 | { |
118 | loff_t final = end - pos + first; /* The final byte of the buffer */ | |
119 | ||
120 | if (first > 0) | |
e2e05394 | 121 | clear_pmem(addr, first); |
d475c634 | 122 | if (final < size) |
e2e05394 | 123 | clear_pmem(addr + final, size - final); |
d475c634 MW |
124 | } |
125 | ||
126 | static bool buffer_written(struct buffer_head *bh) | |
127 | { | |
128 | return buffer_mapped(bh) && !buffer_unwritten(bh); | |
129 | } | |
130 | ||
131 | /* | |
132 | * When ext4 encounters a hole, it returns without modifying the buffer_head | |
133 | * which means that we can't trust b_size. To cope with this, we set b_state | |
134 | * to 0 before calling get_block and, if any bit is set, we know we can trust | |
135 | * b_size. Unfortunate, really, since ext4 knows precisely how long a hole is | |
136 | * and would save us time calling get_block repeatedly. | |
137 | */ | |
138 | static bool buffer_size_valid(struct buffer_head *bh) | |
139 | { | |
140 | return bh->b_state != 0; | |
141 | } | |
142 | ||
b2e0d162 DW |
143 | |
144 | static sector_t to_sector(const struct buffer_head *bh, | |
145 | const struct inode *inode) | |
146 | { | |
147 | sector_t sector = bh->b_blocknr << (inode->i_blkbits - 9); | |
148 | ||
149 | return sector; | |
150 | } | |
151 | ||
a95cd631 OS |
152 | static ssize_t dax_io(struct inode *inode, struct iov_iter *iter, |
153 | loff_t start, loff_t end, get_block_t get_block, | |
154 | struct buffer_head *bh) | |
d475c634 | 155 | { |
b2e0d162 DW |
156 | loff_t pos = start, max = start, bh_max = start; |
157 | bool hole = false, need_wmb = false; | |
158 | struct block_device *bdev = NULL; | |
159 | int rw = iov_iter_rw(iter), rc; | |
160 | long map_len = 0; | |
161 | struct blk_dax_ctl dax = { | |
162 | .addr = (void __pmem *) ERR_PTR(-EIO), | |
163 | }; | |
164 | ||
165 | if (rw == READ) | |
d475c634 MW |
166 | end = min(end, i_size_read(inode)); |
167 | ||
168 | while (pos < end) { | |
2765cfbb | 169 | size_t len; |
d475c634 MW |
170 | if (pos == max) { |
171 | unsigned blkbits = inode->i_blkbits; | |
e94f5a22 JM |
172 | long page = pos >> PAGE_SHIFT; |
173 | sector_t block = page << (PAGE_SHIFT - blkbits); | |
d475c634 MW |
174 | unsigned first = pos - (block << blkbits); |
175 | long size; | |
176 | ||
177 | if (pos == bh_max) { | |
178 | bh->b_size = PAGE_ALIGN(end - pos); | |
179 | bh->b_state = 0; | |
b2e0d162 DW |
180 | rc = get_block(inode, block, bh, rw == WRITE); |
181 | if (rc) | |
d475c634 MW |
182 | break; |
183 | if (!buffer_size_valid(bh)) | |
184 | bh->b_size = 1 << blkbits; | |
185 | bh_max = pos - first + bh->b_size; | |
b2e0d162 | 186 | bdev = bh->b_bdev; |
d475c634 MW |
187 | } else { |
188 | unsigned done = bh->b_size - | |
189 | (bh_max - (pos - first)); | |
190 | bh->b_blocknr += done >> blkbits; | |
191 | bh->b_size -= done; | |
192 | } | |
193 | ||
b2e0d162 | 194 | hole = rw == READ && !buffer_written(bh); |
d475c634 | 195 | if (hole) { |
d475c634 MW |
196 | size = bh->b_size - first; |
197 | } else { | |
b2e0d162 DW |
198 | dax_unmap_atomic(bdev, &dax); |
199 | dax.sector = to_sector(bh, inode); | |
200 | dax.size = bh->b_size; | |
201 | map_len = dax_map_atomic(bdev, &dax); | |
202 | if (map_len < 0) { | |
203 | rc = map_len; | |
d475c634 | 204 | break; |
b2e0d162 | 205 | } |
2765cfbb | 206 | if (buffer_unwritten(bh) || buffer_new(bh)) { |
b2e0d162 DW |
207 | dax_new_buf(dax.addr, map_len, first, |
208 | pos, end); | |
2765cfbb RZ |
209 | need_wmb = true; |
210 | } | |
b2e0d162 DW |
211 | dax.addr += first; |
212 | size = map_len - first; | |
d475c634 MW |
213 | } |
214 | max = min(pos + size, end); | |
215 | } | |
216 | ||
2765cfbb | 217 | if (iov_iter_rw(iter) == WRITE) { |
b2e0d162 | 218 | len = copy_from_iter_pmem(dax.addr, max - pos, iter); |
2765cfbb RZ |
219 | need_wmb = true; |
220 | } else if (!hole) | |
b2e0d162 | 221 | len = copy_to_iter((void __force *) dax.addr, max - pos, |
e2e05394 | 222 | iter); |
d475c634 MW |
223 | else |
224 | len = iov_iter_zero(max - pos, iter); | |
225 | ||
cadfbb6e | 226 | if (!len) { |
b2e0d162 | 227 | rc = -EFAULT; |
d475c634 | 228 | break; |
cadfbb6e | 229 | } |
d475c634 MW |
230 | |
231 | pos += len; | |
b2e0d162 DW |
232 | if (!IS_ERR(dax.addr)) |
233 | dax.addr += len; | |
d475c634 MW |
234 | } |
235 | ||
2765cfbb RZ |
236 | if (need_wmb) |
237 | wmb_pmem(); | |
b2e0d162 | 238 | dax_unmap_atomic(bdev, &dax); |
2765cfbb | 239 | |
b2e0d162 | 240 | return (pos == start) ? rc : pos - start; |
d475c634 MW |
241 | } |
242 | ||
243 | /** | |
244 | * dax_do_io - Perform I/O to a DAX file | |
d475c634 MW |
245 | * @iocb: The control block for this I/O |
246 | * @inode: The file which the I/O is directed at | |
247 | * @iter: The addresses to do I/O from or to | |
248 | * @pos: The file offset where the I/O starts | |
249 | * @get_block: The filesystem method used to translate file offsets to blocks | |
250 | * @end_io: A filesystem callback for I/O completion | |
251 | * @flags: See below | |
252 | * | |
253 | * This function uses the same locking scheme as do_blockdev_direct_IO: | |
254 | * If @flags has DIO_LOCKING set, we assume that the i_mutex is held by the | |
255 | * caller for writes. For reads, we take and release the i_mutex ourselves. | |
256 | * If DIO_LOCKING is not set, the filesystem takes care of its own locking. | |
257 | * As with do_blockdev_direct_IO(), we increment i_dio_count while the I/O | |
258 | * is in progress. | |
259 | */ | |
a95cd631 OS |
260 | ssize_t dax_do_io(struct kiocb *iocb, struct inode *inode, |
261 | struct iov_iter *iter, loff_t pos, get_block_t get_block, | |
262 | dio_iodone_t end_io, int flags) | |
d475c634 MW |
263 | { |
264 | struct buffer_head bh; | |
265 | ssize_t retval = -EINVAL; | |
266 | loff_t end = pos + iov_iter_count(iter); | |
267 | ||
268 | memset(&bh, 0, sizeof(bh)); | |
eab95db6 | 269 | bh.b_bdev = inode->i_sb->s_bdev; |
d475c634 | 270 | |
a95cd631 | 271 | if ((flags & DIO_LOCKING) && iov_iter_rw(iter) == READ) { |
d475c634 | 272 | struct address_space *mapping = inode->i_mapping; |
5955102c | 273 | inode_lock(inode); |
d475c634 MW |
274 | retval = filemap_write_and_wait_range(mapping, pos, end - 1); |
275 | if (retval) { | |
5955102c | 276 | inode_unlock(inode); |
d475c634 MW |
277 | goto out; |
278 | } | |
279 | } | |
280 | ||
281 | /* Protects against truncate */ | |
bbab37dd MW |
282 | if (!(flags & DIO_SKIP_DIO_COUNT)) |
283 | inode_dio_begin(inode); | |
d475c634 | 284 | |
a95cd631 | 285 | retval = dax_io(inode, iter, pos, end, get_block, &bh); |
d475c634 | 286 | |
a95cd631 | 287 | if ((flags & DIO_LOCKING) && iov_iter_rw(iter) == READ) |
5955102c | 288 | inode_unlock(inode); |
d475c634 MW |
289 | |
290 | if ((retval > 0) && end_io) | |
291 | end_io(iocb, pos, retval, bh.b_private); | |
292 | ||
bbab37dd MW |
293 | if (!(flags & DIO_SKIP_DIO_COUNT)) |
294 | inode_dio_end(inode); | |
d475c634 MW |
295 | out: |
296 | return retval; | |
297 | } | |
298 | EXPORT_SYMBOL_GPL(dax_do_io); | |
f7ca90b1 MW |
299 | |
300 | /* | |
301 | * The user has performed a load from a hole in the file. Allocating | |
302 | * a new page in the file would cause excessive storage usage for | |
303 | * workloads with sparse files. We allocate a page cache page instead. | |
304 | * We'll kick it out of the page cache if it's ever written to, | |
305 | * otherwise it will simply fall out of the page cache under memory | |
306 | * pressure without ever having been dirtied. | |
307 | */ | |
308 | static int dax_load_hole(struct address_space *mapping, struct page *page, | |
309 | struct vm_fault *vmf) | |
310 | { | |
311 | unsigned long size; | |
312 | struct inode *inode = mapping->host; | |
313 | if (!page) | |
314 | page = find_or_create_page(mapping, vmf->pgoff, | |
315 | GFP_KERNEL | __GFP_ZERO); | |
316 | if (!page) | |
317 | return VM_FAULT_OOM; | |
318 | /* Recheck i_size under page lock to avoid truncate race */ | |
319 | size = (i_size_read(inode) + PAGE_SIZE - 1) >> PAGE_SHIFT; | |
320 | if (vmf->pgoff >= size) { | |
321 | unlock_page(page); | |
322 | page_cache_release(page); | |
323 | return VM_FAULT_SIGBUS; | |
324 | } | |
325 | ||
326 | vmf->page = page; | |
327 | return VM_FAULT_LOCKED; | |
328 | } | |
329 | ||
b2e0d162 DW |
330 | static int copy_user_bh(struct page *to, struct inode *inode, |
331 | struct buffer_head *bh, unsigned long vaddr) | |
f7ca90b1 | 332 | { |
b2e0d162 DW |
333 | struct blk_dax_ctl dax = { |
334 | .sector = to_sector(bh, inode), | |
335 | .size = bh->b_size, | |
336 | }; | |
337 | struct block_device *bdev = bh->b_bdev; | |
e2e05394 RZ |
338 | void *vto; |
339 | ||
b2e0d162 DW |
340 | if (dax_map_atomic(bdev, &dax) < 0) |
341 | return PTR_ERR(dax.addr); | |
f7ca90b1 | 342 | vto = kmap_atomic(to); |
b2e0d162 | 343 | copy_user_page(vto, (void __force *)dax.addr, vaddr, to); |
f7ca90b1 | 344 | kunmap_atomic(vto); |
b2e0d162 | 345 | dax_unmap_atomic(bdev, &dax); |
f7ca90b1 MW |
346 | return 0; |
347 | } | |
348 | ||
9973c98e RZ |
349 | #define NO_SECTOR -1 |
350 | #define DAX_PMD_INDEX(page_index) (page_index & (PMD_MASK >> PAGE_CACHE_SHIFT)) | |
351 | ||
352 | static int dax_radix_entry(struct address_space *mapping, pgoff_t index, | |
353 | sector_t sector, bool pmd_entry, bool dirty) | |
354 | { | |
355 | struct radix_tree_root *page_tree = &mapping->page_tree; | |
356 | pgoff_t pmd_index = DAX_PMD_INDEX(index); | |
357 | int type, error = 0; | |
358 | void *entry; | |
359 | ||
360 | WARN_ON_ONCE(pmd_entry && !dirty); | |
361 | __mark_inode_dirty(mapping->host, I_DIRTY_PAGES); | |
362 | ||
363 | spin_lock_irq(&mapping->tree_lock); | |
364 | ||
365 | entry = radix_tree_lookup(page_tree, pmd_index); | |
366 | if (entry && RADIX_DAX_TYPE(entry) == RADIX_DAX_PMD) { | |
367 | index = pmd_index; | |
368 | goto dirty; | |
369 | } | |
370 | ||
371 | entry = radix_tree_lookup(page_tree, index); | |
372 | if (entry) { | |
373 | type = RADIX_DAX_TYPE(entry); | |
374 | if (WARN_ON_ONCE(type != RADIX_DAX_PTE && | |
375 | type != RADIX_DAX_PMD)) { | |
376 | error = -EIO; | |
377 | goto unlock; | |
378 | } | |
379 | ||
380 | if (!pmd_entry || type == RADIX_DAX_PMD) | |
381 | goto dirty; | |
382 | ||
383 | /* | |
384 | * We only insert dirty PMD entries into the radix tree. This | |
385 | * means we don't need to worry about removing a dirty PTE | |
386 | * entry and inserting a clean PMD entry, thus reducing the | |
387 | * range we would flush with a follow-up fsync/msync call. | |
388 | */ | |
389 | radix_tree_delete(&mapping->page_tree, index); | |
390 | mapping->nrexceptional--; | |
391 | } | |
392 | ||
393 | if (sector == NO_SECTOR) { | |
394 | /* | |
395 | * This can happen during correct operation if our pfn_mkwrite | |
396 | * fault raced against a hole punch operation. If this | |
397 | * happens the pte that was hole punched will have been | |
398 | * unmapped and the radix tree entry will have been removed by | |
399 | * the time we are called, but the call will still happen. We | |
400 | * will return all the way up to wp_pfn_shared(), where the | |
401 | * pte_same() check will fail, eventually causing page fault | |
402 | * to be retried by the CPU. | |
403 | */ | |
404 | goto unlock; | |
405 | } | |
406 | ||
407 | error = radix_tree_insert(page_tree, index, | |
408 | RADIX_DAX_ENTRY(sector, pmd_entry)); | |
409 | if (error) | |
410 | goto unlock; | |
411 | ||
412 | mapping->nrexceptional++; | |
413 | dirty: | |
414 | if (dirty) | |
415 | radix_tree_tag_set(page_tree, index, PAGECACHE_TAG_DIRTY); | |
416 | unlock: | |
417 | spin_unlock_irq(&mapping->tree_lock); | |
418 | return error; | |
419 | } | |
420 | ||
421 | static int dax_writeback_one(struct block_device *bdev, | |
422 | struct address_space *mapping, pgoff_t index, void *entry) | |
423 | { | |
424 | struct radix_tree_root *page_tree = &mapping->page_tree; | |
425 | int type = RADIX_DAX_TYPE(entry); | |
426 | struct radix_tree_node *node; | |
427 | struct blk_dax_ctl dax; | |
428 | void **slot; | |
429 | int ret = 0; | |
430 | ||
431 | spin_lock_irq(&mapping->tree_lock); | |
432 | /* | |
433 | * Regular page slots are stabilized by the page lock even | |
434 | * without the tree itself locked. These unlocked entries | |
435 | * need verification under the tree lock. | |
436 | */ | |
437 | if (!__radix_tree_lookup(page_tree, index, &node, &slot)) | |
438 | goto unlock; | |
439 | if (*slot != entry) | |
440 | goto unlock; | |
441 | ||
442 | /* another fsync thread may have already written back this entry */ | |
443 | if (!radix_tree_tag_get(page_tree, index, PAGECACHE_TAG_TOWRITE)) | |
444 | goto unlock; | |
445 | ||
446 | if (WARN_ON_ONCE(type != RADIX_DAX_PTE && type != RADIX_DAX_PMD)) { | |
447 | ret = -EIO; | |
448 | goto unlock; | |
449 | } | |
450 | ||
451 | dax.sector = RADIX_DAX_SECTOR(entry); | |
452 | dax.size = (type == RADIX_DAX_PMD ? PMD_SIZE : PAGE_SIZE); | |
453 | spin_unlock_irq(&mapping->tree_lock); | |
454 | ||
455 | /* | |
456 | * We cannot hold tree_lock while calling dax_map_atomic() because it | |
457 | * eventually calls cond_resched(). | |
458 | */ | |
459 | ret = dax_map_atomic(bdev, &dax); | |
460 | if (ret < 0) | |
461 | return ret; | |
462 | ||
463 | if (WARN_ON_ONCE(ret < dax.size)) { | |
464 | ret = -EIO; | |
465 | goto unmap; | |
466 | } | |
467 | ||
468 | wb_cache_pmem(dax.addr, dax.size); | |
469 | ||
470 | spin_lock_irq(&mapping->tree_lock); | |
471 | radix_tree_tag_clear(page_tree, index, PAGECACHE_TAG_TOWRITE); | |
472 | spin_unlock_irq(&mapping->tree_lock); | |
473 | unmap: | |
474 | dax_unmap_atomic(bdev, &dax); | |
475 | return ret; | |
476 | ||
477 | unlock: | |
478 | spin_unlock_irq(&mapping->tree_lock); | |
479 | return ret; | |
480 | } | |
481 | ||
482 | /* | |
483 | * Flush the mapping to the persistent domain within the byte range of [start, | |
484 | * end]. This is required by data integrity operations to ensure file data is | |
485 | * on persistent storage prior to completion of the operation. | |
486 | */ | |
487 | int dax_writeback_mapping_range(struct address_space *mapping, loff_t start, | |
488 | loff_t end) | |
489 | { | |
490 | struct inode *inode = mapping->host; | |
491 | struct block_device *bdev = inode->i_sb->s_bdev; | |
492 | pgoff_t start_index, end_index, pmd_index; | |
493 | pgoff_t indices[PAGEVEC_SIZE]; | |
494 | struct pagevec pvec; | |
495 | bool done = false; | |
496 | int i, ret = 0; | |
497 | void *entry; | |
498 | ||
499 | if (WARN_ON_ONCE(inode->i_blkbits != PAGE_SHIFT)) | |
500 | return -EIO; | |
501 | ||
502 | start_index = start >> PAGE_CACHE_SHIFT; | |
503 | end_index = end >> PAGE_CACHE_SHIFT; | |
504 | pmd_index = DAX_PMD_INDEX(start_index); | |
505 | ||
506 | rcu_read_lock(); | |
507 | entry = radix_tree_lookup(&mapping->page_tree, pmd_index); | |
508 | rcu_read_unlock(); | |
509 | ||
510 | /* see if the start of our range is covered by a PMD entry */ | |
511 | if (entry && RADIX_DAX_TYPE(entry) == RADIX_DAX_PMD) | |
512 | start_index = pmd_index; | |
513 | ||
514 | tag_pages_for_writeback(mapping, start_index, end_index); | |
515 | ||
516 | pagevec_init(&pvec, 0); | |
517 | while (!done) { | |
518 | pvec.nr = find_get_entries_tag(mapping, start_index, | |
519 | PAGECACHE_TAG_TOWRITE, PAGEVEC_SIZE, | |
520 | pvec.pages, indices); | |
521 | ||
522 | if (pvec.nr == 0) | |
523 | break; | |
524 | ||
525 | for (i = 0; i < pvec.nr; i++) { | |
526 | if (indices[i] > end_index) { | |
527 | done = true; | |
528 | break; | |
529 | } | |
530 | ||
531 | ret = dax_writeback_one(bdev, mapping, indices[i], | |
532 | pvec.pages[i]); | |
533 | if (ret < 0) | |
534 | return ret; | |
535 | } | |
536 | } | |
537 | wmb_pmem(); | |
538 | return 0; | |
539 | } | |
540 | EXPORT_SYMBOL_GPL(dax_writeback_mapping_range); | |
541 | ||
f7ca90b1 MW |
542 | static int dax_insert_mapping(struct inode *inode, struct buffer_head *bh, |
543 | struct vm_area_struct *vma, struct vm_fault *vmf) | |
544 | { | |
f7ca90b1 | 545 | unsigned long vaddr = (unsigned long)vmf->virtual_address; |
b2e0d162 DW |
546 | struct address_space *mapping = inode->i_mapping; |
547 | struct block_device *bdev = bh->b_bdev; | |
548 | struct blk_dax_ctl dax = { | |
549 | .sector = to_sector(bh, inode), | |
550 | .size = bh->b_size, | |
551 | }; | |
f7ca90b1 MW |
552 | pgoff_t size; |
553 | int error; | |
554 | ||
0f90cc66 RZ |
555 | i_mmap_lock_read(mapping); |
556 | ||
f7ca90b1 MW |
557 | /* |
558 | * Check truncate didn't happen while we were allocating a block. | |
559 | * If it did, this block may or may not be still allocated to the | |
560 | * file. We can't tell the filesystem to free it because we can't | |
561 | * take i_mutex here. In the worst case, the file still has blocks | |
562 | * allocated past the end of the file. | |
563 | */ | |
564 | size = (i_size_read(inode) + PAGE_SIZE - 1) >> PAGE_SHIFT; | |
565 | if (unlikely(vmf->pgoff >= size)) { | |
566 | error = -EIO; | |
567 | goto out; | |
568 | } | |
569 | ||
b2e0d162 DW |
570 | if (dax_map_atomic(bdev, &dax) < 0) { |
571 | error = PTR_ERR(dax.addr); | |
f7ca90b1 MW |
572 | goto out; |
573 | } | |
574 | ||
2765cfbb | 575 | if (buffer_unwritten(bh) || buffer_new(bh)) { |
b2e0d162 | 576 | clear_pmem(dax.addr, PAGE_SIZE); |
2765cfbb RZ |
577 | wmb_pmem(); |
578 | } | |
b2e0d162 | 579 | dax_unmap_atomic(bdev, &dax); |
f7ca90b1 | 580 | |
9973c98e RZ |
581 | error = dax_radix_entry(mapping, vmf->pgoff, dax.sector, false, |
582 | vmf->flags & FAULT_FLAG_WRITE); | |
583 | if (error) | |
584 | goto out; | |
585 | ||
01c8f1c4 | 586 | error = vm_insert_mixed(vma, vaddr, dax.pfn); |
f7ca90b1 MW |
587 | |
588 | out: | |
0f90cc66 RZ |
589 | i_mmap_unlock_read(mapping); |
590 | ||
f7ca90b1 MW |
591 | return error; |
592 | } | |
593 | ||
ce5c5d55 DC |
594 | /** |
595 | * __dax_fault - handle a page fault on a DAX file | |
596 | * @vma: The virtual memory area where the fault occurred | |
597 | * @vmf: The description of the fault | |
598 | * @get_block: The filesystem method used to translate file offsets to blocks | |
b2442c5a DC |
599 | * @complete_unwritten: The filesystem method used to convert unwritten blocks |
600 | * to written so the data written to them is exposed. This is required for | |
601 | * required by write faults for filesystems that will return unwritten | |
602 | * extent mappings from @get_block, but it is optional for reads as | |
603 | * dax_insert_mapping() will always zero unwritten blocks. If the fs does | |
604 | * not support unwritten extents, the it should pass NULL. | |
ce5c5d55 DC |
605 | * |
606 | * When a page fault occurs, filesystems may call this helper in their | |
607 | * fault handler for DAX files. __dax_fault() assumes the caller has done all | |
608 | * the necessary locking for the page fault to proceed successfully. | |
609 | */ | |
610 | int __dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf, | |
e842f290 | 611 | get_block_t get_block, dax_iodone_t complete_unwritten) |
f7ca90b1 MW |
612 | { |
613 | struct file *file = vma->vm_file; | |
614 | struct address_space *mapping = file->f_mapping; | |
615 | struct inode *inode = mapping->host; | |
616 | struct page *page; | |
617 | struct buffer_head bh; | |
618 | unsigned long vaddr = (unsigned long)vmf->virtual_address; | |
619 | unsigned blkbits = inode->i_blkbits; | |
620 | sector_t block; | |
621 | pgoff_t size; | |
622 | int error; | |
623 | int major = 0; | |
624 | ||
625 | size = (i_size_read(inode) + PAGE_SIZE - 1) >> PAGE_SHIFT; | |
626 | if (vmf->pgoff >= size) | |
627 | return VM_FAULT_SIGBUS; | |
628 | ||
629 | memset(&bh, 0, sizeof(bh)); | |
630 | block = (sector_t)vmf->pgoff << (PAGE_SHIFT - blkbits); | |
eab95db6 | 631 | bh.b_bdev = inode->i_sb->s_bdev; |
f7ca90b1 MW |
632 | bh.b_size = PAGE_SIZE; |
633 | ||
634 | repeat: | |
635 | page = find_get_page(mapping, vmf->pgoff); | |
636 | if (page) { | |
637 | if (!lock_page_or_retry(page, vma->vm_mm, vmf->flags)) { | |
638 | page_cache_release(page); | |
639 | return VM_FAULT_RETRY; | |
640 | } | |
641 | if (unlikely(page->mapping != mapping)) { | |
642 | unlock_page(page); | |
643 | page_cache_release(page); | |
644 | goto repeat; | |
645 | } | |
646 | size = (i_size_read(inode) + PAGE_SIZE - 1) >> PAGE_SHIFT; | |
647 | if (unlikely(vmf->pgoff >= size)) { | |
648 | /* | |
649 | * We have a struct page covering a hole in the file | |
650 | * from a read fault and we've raced with a truncate | |
651 | */ | |
652 | error = -EIO; | |
0f90cc66 | 653 | goto unlock_page; |
f7ca90b1 MW |
654 | } |
655 | } | |
656 | ||
657 | error = get_block(inode, block, &bh, 0); | |
658 | if (!error && (bh.b_size < PAGE_SIZE)) | |
659 | error = -EIO; /* fs corruption? */ | |
660 | if (error) | |
0f90cc66 | 661 | goto unlock_page; |
f7ca90b1 MW |
662 | |
663 | if (!buffer_mapped(&bh) && !buffer_unwritten(&bh) && !vmf->cow_page) { | |
664 | if (vmf->flags & FAULT_FLAG_WRITE) { | |
665 | error = get_block(inode, block, &bh, 1); | |
666 | count_vm_event(PGMAJFAULT); | |
667 | mem_cgroup_count_vm_event(vma->vm_mm, PGMAJFAULT); | |
668 | major = VM_FAULT_MAJOR; | |
669 | if (!error && (bh.b_size < PAGE_SIZE)) | |
670 | error = -EIO; | |
671 | if (error) | |
0f90cc66 | 672 | goto unlock_page; |
f7ca90b1 MW |
673 | } else { |
674 | return dax_load_hole(mapping, page, vmf); | |
675 | } | |
676 | } | |
677 | ||
678 | if (vmf->cow_page) { | |
679 | struct page *new_page = vmf->cow_page; | |
680 | if (buffer_written(&bh)) | |
b2e0d162 | 681 | error = copy_user_bh(new_page, inode, &bh, vaddr); |
f7ca90b1 MW |
682 | else |
683 | clear_user_highpage(new_page, vaddr); | |
684 | if (error) | |
0f90cc66 | 685 | goto unlock_page; |
f7ca90b1 MW |
686 | vmf->page = page; |
687 | if (!page) { | |
0f90cc66 | 688 | i_mmap_lock_read(mapping); |
f7ca90b1 MW |
689 | /* Check we didn't race with truncate */ |
690 | size = (i_size_read(inode) + PAGE_SIZE - 1) >> | |
691 | PAGE_SHIFT; | |
692 | if (vmf->pgoff >= size) { | |
0f90cc66 | 693 | i_mmap_unlock_read(mapping); |
f7ca90b1 | 694 | error = -EIO; |
0f90cc66 | 695 | goto out; |
f7ca90b1 MW |
696 | } |
697 | } | |
698 | return VM_FAULT_LOCKED; | |
699 | } | |
700 | ||
701 | /* Check we didn't race with a read fault installing a new page */ | |
702 | if (!page && major) | |
703 | page = find_lock_page(mapping, vmf->pgoff); | |
704 | ||
705 | if (page) { | |
706 | unmap_mapping_range(mapping, vmf->pgoff << PAGE_SHIFT, | |
707 | PAGE_CACHE_SIZE, 0); | |
708 | delete_from_page_cache(page); | |
709 | unlock_page(page); | |
710 | page_cache_release(page); | |
9973c98e | 711 | page = NULL; |
f7ca90b1 MW |
712 | } |
713 | ||
e842f290 DC |
714 | /* |
715 | * If we successfully insert the new mapping over an unwritten extent, | |
716 | * we need to ensure we convert the unwritten extent. If there is an | |
717 | * error inserting the mapping, the filesystem needs to leave it as | |
718 | * unwritten to prevent exposure of the stale underlying data to | |
719 | * userspace, but we still need to call the completion function so | |
720 | * the private resources on the mapping buffer can be released. We | |
721 | * indicate what the callback should do via the uptodate variable, same | |
722 | * as for normal BH based IO completions. | |
723 | */ | |
f7ca90b1 | 724 | error = dax_insert_mapping(inode, &bh, vma, vmf); |
b2442c5a DC |
725 | if (buffer_unwritten(&bh)) { |
726 | if (complete_unwritten) | |
727 | complete_unwritten(&bh, !error); | |
728 | else | |
729 | WARN_ON_ONCE(!(vmf->flags & FAULT_FLAG_WRITE)); | |
730 | } | |
f7ca90b1 MW |
731 | |
732 | out: | |
733 | if (error == -ENOMEM) | |
734 | return VM_FAULT_OOM | major; | |
735 | /* -EBUSY is fine, somebody else faulted on the same PTE */ | |
736 | if ((error < 0) && (error != -EBUSY)) | |
737 | return VM_FAULT_SIGBUS | major; | |
738 | return VM_FAULT_NOPAGE | major; | |
739 | ||
0f90cc66 | 740 | unlock_page: |
f7ca90b1 MW |
741 | if (page) { |
742 | unlock_page(page); | |
743 | page_cache_release(page); | |
744 | } | |
745 | goto out; | |
746 | } | |
ce5c5d55 | 747 | EXPORT_SYMBOL(__dax_fault); |
f7ca90b1 MW |
748 | |
749 | /** | |
750 | * dax_fault - handle a page fault on a DAX file | |
751 | * @vma: The virtual memory area where the fault occurred | |
752 | * @vmf: The description of the fault | |
753 | * @get_block: The filesystem method used to translate file offsets to blocks | |
754 | * | |
755 | * When a page fault occurs, filesystems may call this helper in their | |
756 | * fault handler for DAX files. | |
757 | */ | |
758 | int dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf, | |
e842f290 | 759 | get_block_t get_block, dax_iodone_t complete_unwritten) |
f7ca90b1 MW |
760 | { |
761 | int result; | |
762 | struct super_block *sb = file_inode(vma->vm_file)->i_sb; | |
763 | ||
764 | if (vmf->flags & FAULT_FLAG_WRITE) { | |
765 | sb_start_pagefault(sb); | |
766 | file_update_time(vma->vm_file); | |
767 | } | |
ce5c5d55 | 768 | result = __dax_fault(vma, vmf, get_block, complete_unwritten); |
f7ca90b1 MW |
769 | if (vmf->flags & FAULT_FLAG_WRITE) |
770 | sb_end_pagefault(sb); | |
771 | ||
772 | return result; | |
773 | } | |
774 | EXPORT_SYMBOL_GPL(dax_fault); | |
4c0ccfef | 775 | |
844f35db MW |
776 | #ifdef CONFIG_TRANSPARENT_HUGEPAGE |
777 | /* | |
778 | * The 'colour' (ie low bits) within a PMD of a page offset. This comes up | |
779 | * more often than one might expect in the below function. | |
780 | */ | |
781 | #define PG_PMD_COLOUR ((PMD_SIZE >> PAGE_SHIFT) - 1) | |
782 | ||
cbb38e41 DW |
783 | static void __dax_dbg(struct buffer_head *bh, unsigned long address, |
784 | const char *reason, const char *fn) | |
785 | { | |
786 | if (bh) { | |
787 | char bname[BDEVNAME_SIZE]; | |
788 | bdevname(bh->b_bdev, bname); | |
789 | pr_debug("%s: %s addr: %lx dev %s state %lx start %lld " | |
790 | "length %zd fallback: %s\n", fn, current->comm, | |
791 | address, bname, bh->b_state, (u64)bh->b_blocknr, | |
792 | bh->b_size, reason); | |
793 | } else { | |
794 | pr_debug("%s: %s addr: %lx fallback: %s\n", fn, | |
795 | current->comm, address, reason); | |
796 | } | |
797 | } | |
798 | ||
799 | #define dax_pmd_dbg(bh, address, reason) __dax_dbg(bh, address, reason, "dax_pmd") | |
800 | ||
844f35db MW |
801 | int __dax_pmd_fault(struct vm_area_struct *vma, unsigned long address, |
802 | pmd_t *pmd, unsigned int flags, get_block_t get_block, | |
803 | dax_iodone_t complete_unwritten) | |
804 | { | |
805 | struct file *file = vma->vm_file; | |
806 | struct address_space *mapping = file->f_mapping; | |
807 | struct inode *inode = mapping->host; | |
808 | struct buffer_head bh; | |
809 | unsigned blkbits = inode->i_blkbits; | |
810 | unsigned long pmd_addr = address & PMD_MASK; | |
811 | bool write = flags & FAULT_FLAG_WRITE; | |
b2e0d162 | 812 | struct block_device *bdev; |
844f35db | 813 | pgoff_t size, pgoff; |
b2e0d162 | 814 | sector_t block; |
9973c98e RZ |
815 | int error, result = 0; |
816 | bool alloc = false; | |
844f35db | 817 | |
c046c321 | 818 | /* dax pmd mappings require pfn_t_devmap() */ |
ee82c9ed DW |
819 | if (!IS_ENABLED(CONFIG_FS_DAX_PMD)) |
820 | return VM_FAULT_FALLBACK; | |
821 | ||
844f35db | 822 | /* Fall back to PTEs if we're going to COW */ |
59bf4fb9 TK |
823 | if (write && !(vma->vm_flags & VM_SHARED)) { |
824 | split_huge_pmd(vma, pmd, address); | |
cbb38e41 | 825 | dax_pmd_dbg(NULL, address, "cow write"); |
844f35db | 826 | return VM_FAULT_FALLBACK; |
59bf4fb9 | 827 | } |
844f35db | 828 | /* If the PMD would extend outside the VMA */ |
cbb38e41 DW |
829 | if (pmd_addr < vma->vm_start) { |
830 | dax_pmd_dbg(NULL, address, "vma start unaligned"); | |
844f35db | 831 | return VM_FAULT_FALLBACK; |
cbb38e41 DW |
832 | } |
833 | if ((pmd_addr + PMD_SIZE) > vma->vm_end) { | |
834 | dax_pmd_dbg(NULL, address, "vma end unaligned"); | |
844f35db | 835 | return VM_FAULT_FALLBACK; |
cbb38e41 | 836 | } |
844f35db | 837 | |
3fdd1b47 | 838 | pgoff = linear_page_index(vma, pmd_addr); |
844f35db MW |
839 | size = (i_size_read(inode) + PAGE_SIZE - 1) >> PAGE_SHIFT; |
840 | if (pgoff >= size) | |
841 | return VM_FAULT_SIGBUS; | |
842 | /* If the PMD would cover blocks out of the file */ | |
cbb38e41 DW |
843 | if ((pgoff | PG_PMD_COLOUR) >= size) { |
844 | dax_pmd_dbg(NULL, address, | |
845 | "offset + huge page size > file size"); | |
844f35db | 846 | return VM_FAULT_FALLBACK; |
cbb38e41 | 847 | } |
844f35db MW |
848 | |
849 | memset(&bh, 0, sizeof(bh)); | |
d4bbe706 | 850 | bh.b_bdev = inode->i_sb->s_bdev; |
844f35db MW |
851 | block = (sector_t)pgoff << (PAGE_SHIFT - blkbits); |
852 | ||
853 | bh.b_size = PMD_SIZE; | |
9973c98e RZ |
854 | |
855 | if (get_block(inode, block, &bh, 0) != 0) | |
844f35db | 856 | return VM_FAULT_SIGBUS; |
9973c98e RZ |
857 | |
858 | if (!buffer_mapped(&bh) && write) { | |
859 | if (get_block(inode, block, &bh, 1) != 0) | |
860 | return VM_FAULT_SIGBUS; | |
861 | alloc = true; | |
862 | } | |
863 | ||
b2e0d162 | 864 | bdev = bh.b_bdev; |
844f35db MW |
865 | |
866 | /* | |
867 | * If the filesystem isn't willing to tell us the length of a hole, | |
868 | * just fall back to PTEs. Calling get_block 512 times in a loop | |
869 | * would be silly. | |
870 | */ | |
cbb38e41 DW |
871 | if (!buffer_size_valid(&bh) || bh.b_size < PMD_SIZE) { |
872 | dax_pmd_dbg(&bh, address, "allocated block too small"); | |
9973c98e RZ |
873 | return VM_FAULT_FALLBACK; |
874 | } | |
875 | ||
876 | /* | |
877 | * If we allocated new storage, make sure no process has any | |
878 | * zero pages covering this hole | |
879 | */ | |
880 | if (alloc) { | |
881 | loff_t lstart = pgoff << PAGE_SHIFT; | |
882 | loff_t lend = lstart + PMD_SIZE - 1; /* inclusive */ | |
883 | ||
884 | truncate_pagecache_range(inode, lstart, lend); | |
cbb38e41 | 885 | } |
844f35db | 886 | |
de14b9cb | 887 | i_mmap_lock_read(mapping); |
46c043ed | 888 | |
84c4e5e6 MW |
889 | /* |
890 | * If a truncate happened while we were allocating blocks, we may | |
891 | * leave blocks allocated to the file that are beyond EOF. We can't | |
892 | * take i_mutex here, so just leave them hanging; they'll be freed | |
893 | * when the file is deleted. | |
894 | */ | |
844f35db MW |
895 | size = (i_size_read(inode) + PAGE_SIZE - 1) >> PAGE_SHIFT; |
896 | if (pgoff >= size) { | |
897 | result = VM_FAULT_SIGBUS; | |
898 | goto out; | |
899 | } | |
cbb38e41 | 900 | if ((pgoff | PG_PMD_COLOUR) >= size) { |
de14b9cb RZ |
901 | dax_pmd_dbg(&bh, address, |
902 | "offset + huge page size > file size"); | |
844f35db | 903 | goto fallback; |
cbb38e41 | 904 | } |
844f35db | 905 | |
844f35db | 906 | if (!write && !buffer_mapped(&bh) && buffer_uptodate(&bh)) { |
844f35db | 907 | spinlock_t *ptl; |
d295e341 | 908 | pmd_t entry; |
844f35db | 909 | struct page *zero_page = get_huge_zero_page(); |
d295e341 | 910 | |
cbb38e41 DW |
911 | if (unlikely(!zero_page)) { |
912 | dax_pmd_dbg(&bh, address, "no zero page"); | |
844f35db | 913 | goto fallback; |
cbb38e41 | 914 | } |
844f35db | 915 | |
d295e341 KS |
916 | ptl = pmd_lock(vma->vm_mm, pmd); |
917 | if (!pmd_none(*pmd)) { | |
918 | spin_unlock(ptl); | |
cbb38e41 | 919 | dax_pmd_dbg(&bh, address, "pmd already present"); |
d295e341 KS |
920 | goto fallback; |
921 | } | |
922 | ||
cbb38e41 DW |
923 | dev_dbg(part_to_dev(bdev->bd_part), |
924 | "%s: %s addr: %lx pfn: <zero> sect: %llx\n", | |
925 | __func__, current->comm, address, | |
926 | (unsigned long long) to_sector(&bh, inode)); | |
927 | ||
d295e341 KS |
928 | entry = mk_pmd(zero_page, vma->vm_page_prot); |
929 | entry = pmd_mkhuge(entry); | |
930 | set_pmd_at(vma->vm_mm, pmd_addr, pmd, entry); | |
844f35db | 931 | result = VM_FAULT_NOPAGE; |
d295e341 | 932 | spin_unlock(ptl); |
844f35db | 933 | } else { |
b2e0d162 DW |
934 | struct blk_dax_ctl dax = { |
935 | .sector = to_sector(&bh, inode), | |
936 | .size = PMD_SIZE, | |
937 | }; | |
938 | long length = dax_map_atomic(bdev, &dax); | |
939 | ||
844f35db MW |
940 | if (length < 0) { |
941 | result = VM_FAULT_SIGBUS; | |
942 | goto out; | |
943 | } | |
cbb38e41 DW |
944 | if (length < PMD_SIZE) { |
945 | dax_pmd_dbg(&bh, address, "dax-length too small"); | |
946 | dax_unmap_atomic(bdev, &dax); | |
947 | goto fallback; | |
948 | } | |
949 | if (pfn_t_to_pfn(dax.pfn) & PG_PMD_COLOUR) { | |
950 | dax_pmd_dbg(&bh, address, "pfn unaligned"); | |
b2e0d162 | 951 | dax_unmap_atomic(bdev, &dax); |
844f35db | 952 | goto fallback; |
b2e0d162 | 953 | } |
844f35db | 954 | |
c046c321 | 955 | if (!pfn_t_devmap(dax.pfn)) { |
b2e0d162 | 956 | dax_unmap_atomic(bdev, &dax); |
cbb38e41 | 957 | dax_pmd_dbg(&bh, address, "pfn not in memmap"); |
152d7bd8 | 958 | goto fallback; |
b2e0d162 | 959 | } |
152d7bd8 | 960 | |
0f90cc66 | 961 | if (buffer_unwritten(&bh) || buffer_new(&bh)) { |
b2e0d162 | 962 | clear_pmem(dax.addr, PMD_SIZE); |
0f90cc66 RZ |
963 | wmb_pmem(); |
964 | count_vm_event(PGMAJFAULT); | |
965 | mem_cgroup_count_vm_event(vma->vm_mm, PGMAJFAULT); | |
966 | result |= VM_FAULT_MAJOR; | |
967 | } | |
b2e0d162 | 968 | dax_unmap_atomic(bdev, &dax); |
0f90cc66 | 969 | |
9973c98e RZ |
970 | /* |
971 | * For PTE faults we insert a radix tree entry for reads, and | |
972 | * leave it clean. Then on the first write we dirty the radix | |
973 | * tree entry via the dax_pfn_mkwrite() path. This sequence | |
974 | * allows the dax_pfn_mkwrite() call to be simpler and avoid a | |
975 | * call into get_block() to translate the pgoff to a sector in | |
976 | * order to be able to create a new radix tree entry. | |
977 | * | |
978 | * The PMD path doesn't have an equivalent to | |
979 | * dax_pfn_mkwrite(), though, so for a read followed by a | |
980 | * write we traverse all the way through __dax_pmd_fault() | |
981 | * twice. This means we can just skip inserting a radix tree | |
982 | * entry completely on the initial read and just wait until | |
983 | * the write to insert a dirty entry. | |
984 | */ | |
985 | if (write) { | |
986 | error = dax_radix_entry(mapping, pgoff, dax.sector, | |
987 | true, true); | |
988 | if (error) { | |
989 | dax_pmd_dbg(&bh, address, | |
990 | "PMD radix insertion failed"); | |
991 | goto fallback; | |
992 | } | |
993 | } | |
994 | ||
cbb38e41 DW |
995 | dev_dbg(part_to_dev(bdev->bd_part), |
996 | "%s: %s addr: %lx pfn: %lx sect: %llx\n", | |
997 | __func__, current->comm, address, | |
998 | pfn_t_to_pfn(dax.pfn), | |
999 | (unsigned long long) dax.sector); | |
34c0fd54 | 1000 | result |= vmf_insert_pfn_pmd(vma, address, pmd, |
f25748e3 | 1001 | dax.pfn, write); |
844f35db MW |
1002 | } |
1003 | ||
1004 | out: | |
0f90cc66 RZ |
1005 | i_mmap_unlock_read(mapping); |
1006 | ||
844f35db MW |
1007 | if (buffer_unwritten(&bh)) |
1008 | complete_unwritten(&bh, !(result & VM_FAULT_ERROR)); | |
1009 | ||
1010 | return result; | |
1011 | ||
1012 | fallback: | |
1013 | count_vm_event(THP_FAULT_FALLBACK); | |
1014 | result = VM_FAULT_FALLBACK; | |
1015 | goto out; | |
1016 | } | |
1017 | EXPORT_SYMBOL_GPL(__dax_pmd_fault); | |
1018 | ||
1019 | /** | |
1020 | * dax_pmd_fault - handle a PMD fault on a DAX file | |
1021 | * @vma: The virtual memory area where the fault occurred | |
1022 | * @vmf: The description of the fault | |
1023 | * @get_block: The filesystem method used to translate file offsets to blocks | |
1024 | * | |
1025 | * When a page fault occurs, filesystems may call this helper in their | |
1026 | * pmd_fault handler for DAX files. | |
1027 | */ | |
1028 | int dax_pmd_fault(struct vm_area_struct *vma, unsigned long address, | |
1029 | pmd_t *pmd, unsigned int flags, get_block_t get_block, | |
1030 | dax_iodone_t complete_unwritten) | |
1031 | { | |
1032 | int result; | |
1033 | struct super_block *sb = file_inode(vma->vm_file)->i_sb; | |
1034 | ||
1035 | if (flags & FAULT_FLAG_WRITE) { | |
1036 | sb_start_pagefault(sb); | |
1037 | file_update_time(vma->vm_file); | |
1038 | } | |
1039 | result = __dax_pmd_fault(vma, address, pmd, flags, get_block, | |
1040 | complete_unwritten); | |
1041 | if (flags & FAULT_FLAG_WRITE) | |
1042 | sb_end_pagefault(sb); | |
1043 | ||
1044 | return result; | |
1045 | } | |
1046 | EXPORT_SYMBOL_GPL(dax_pmd_fault); | |
dd8a2b6c | 1047 | #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ |
844f35db | 1048 | |
0e3b210c BH |
1049 | /** |
1050 | * dax_pfn_mkwrite - handle first write to DAX page | |
1051 | * @vma: The virtual memory area where the fault occurred | |
1052 | * @vmf: The description of the fault | |
0e3b210c BH |
1053 | */ |
1054 | int dax_pfn_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf) | |
1055 | { | |
9973c98e | 1056 | struct file *file = vma->vm_file; |
0e3b210c | 1057 | |
9973c98e RZ |
1058 | /* |
1059 | * We pass NO_SECTOR to dax_radix_entry() because we expect that a | |
1060 | * RADIX_DAX_PTE entry already exists in the radix tree from a | |
1061 | * previous call to __dax_fault(). We just want to look up that PTE | |
1062 | * entry using vmf->pgoff and make sure the dirty tag is set. This | |
1063 | * saves us from having to make a call to get_block() here to look | |
1064 | * up the sector. | |
1065 | */ | |
1066 | dax_radix_entry(file->f_mapping, vmf->pgoff, NO_SECTOR, false, true); | |
0e3b210c BH |
1067 | return VM_FAULT_NOPAGE; |
1068 | } | |
1069 | EXPORT_SYMBOL_GPL(dax_pfn_mkwrite); | |
1070 | ||
4c0ccfef | 1071 | /** |
25726bc1 | 1072 | * dax_zero_page_range - zero a range within a page of a DAX file |
4c0ccfef MW |
1073 | * @inode: The file being truncated |
1074 | * @from: The file offset that is being truncated to | |
25726bc1 | 1075 | * @length: The number of bytes to zero |
4c0ccfef MW |
1076 | * @get_block: The filesystem method used to translate file offsets to blocks |
1077 | * | |
25726bc1 MW |
1078 | * This function can be called by a filesystem when it is zeroing part of a |
1079 | * page in a DAX file. This is intended for hole-punch operations. If | |
1080 | * you are truncating a file, the helper function dax_truncate_page() may be | |
1081 | * more convenient. | |
4c0ccfef MW |
1082 | * |
1083 | * We work in terms of PAGE_CACHE_SIZE here for commonality with | |
1084 | * block_truncate_page(), but we could go down to PAGE_SIZE if the filesystem | |
1085 | * took care of disposing of the unnecessary blocks. Even if the filesystem | |
1086 | * block size is smaller than PAGE_SIZE, we have to zero the rest of the page | |
25726bc1 | 1087 | * since the file might be mmapped. |
4c0ccfef | 1088 | */ |
25726bc1 MW |
1089 | int dax_zero_page_range(struct inode *inode, loff_t from, unsigned length, |
1090 | get_block_t get_block) | |
4c0ccfef MW |
1091 | { |
1092 | struct buffer_head bh; | |
1093 | pgoff_t index = from >> PAGE_CACHE_SHIFT; | |
1094 | unsigned offset = from & (PAGE_CACHE_SIZE-1); | |
4c0ccfef MW |
1095 | int err; |
1096 | ||
1097 | /* Block boundary? Nothing to do */ | |
1098 | if (!length) | |
1099 | return 0; | |
25726bc1 | 1100 | BUG_ON((offset + length) > PAGE_CACHE_SIZE); |
4c0ccfef MW |
1101 | |
1102 | memset(&bh, 0, sizeof(bh)); | |
eab95db6 | 1103 | bh.b_bdev = inode->i_sb->s_bdev; |
4c0ccfef MW |
1104 | bh.b_size = PAGE_CACHE_SIZE; |
1105 | err = get_block(inode, index, &bh, 0); | |
1106 | if (err < 0) | |
1107 | return err; | |
1108 | if (buffer_written(&bh)) { | |
b2e0d162 DW |
1109 | struct block_device *bdev = bh.b_bdev; |
1110 | struct blk_dax_ctl dax = { | |
1111 | .sector = to_sector(&bh, inode), | |
1112 | .size = PAGE_CACHE_SIZE, | |
1113 | }; | |
1114 | ||
1115 | if (dax_map_atomic(bdev, &dax) < 0) | |
1116 | return PTR_ERR(dax.addr); | |
1117 | clear_pmem(dax.addr + offset, length); | |
2765cfbb | 1118 | wmb_pmem(); |
b2e0d162 | 1119 | dax_unmap_atomic(bdev, &dax); |
4c0ccfef MW |
1120 | } |
1121 | ||
1122 | return 0; | |
1123 | } | |
25726bc1 MW |
1124 | EXPORT_SYMBOL_GPL(dax_zero_page_range); |
1125 | ||
1126 | /** | |
1127 | * dax_truncate_page - handle a partial page being truncated in a DAX file | |
1128 | * @inode: The file being truncated | |
1129 | * @from: The file offset that is being truncated to | |
1130 | * @get_block: The filesystem method used to translate file offsets to blocks | |
1131 | * | |
1132 | * Similar to block_truncate_page(), this function can be called by a | |
1133 | * filesystem when it is truncating a DAX file to handle the partial page. | |
1134 | * | |
1135 | * We work in terms of PAGE_CACHE_SIZE here for commonality with | |
1136 | * block_truncate_page(), but we could go down to PAGE_SIZE if the filesystem | |
1137 | * took care of disposing of the unnecessary blocks. Even if the filesystem | |
1138 | * block size is smaller than PAGE_SIZE, we have to zero the rest of the page | |
1139 | * since the file might be mmapped. | |
1140 | */ | |
1141 | int dax_truncate_page(struct inode *inode, loff_t from, get_block_t get_block) | |
1142 | { | |
1143 | unsigned length = PAGE_CACHE_ALIGN(from) - from; | |
1144 | return dax_zero_page_range(inode, from, length, get_block); | |
1145 | } | |
4c0ccfef | 1146 | EXPORT_SYMBOL_GPL(dax_truncate_page); |