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2025cf9e | 1 | // SPDX-License-Identifier: GPL-2.0-only |
d475c634 MW |
2 | /* |
3 | * fs/dax.c - Direct Access filesystem code | |
4 | * Copyright (c) 2013-2014 Intel Corporation | |
5 | * Author: Matthew Wilcox <[email protected]> | |
6 | * Author: Ross Zwisler <[email protected]> | |
d475c634 MW |
7 | */ |
8 | ||
9 | #include <linux/atomic.h> | |
10 | #include <linux/blkdev.h> | |
11 | #include <linux/buffer_head.h> | |
d77e92e2 | 12 | #include <linux/dax.h> |
d475c634 MW |
13 | #include <linux/fs.h> |
14 | #include <linux/genhd.h> | |
f7ca90b1 MW |
15 | #include <linux/highmem.h> |
16 | #include <linux/memcontrol.h> | |
17 | #include <linux/mm.h> | |
d475c634 | 18 | #include <linux/mutex.h> |
9973c98e | 19 | #include <linux/pagevec.h> |
289c6aed | 20 | #include <linux/sched.h> |
f361bf4a | 21 | #include <linux/sched/signal.h> |
d475c634 | 22 | #include <linux/uio.h> |
f7ca90b1 | 23 | #include <linux/vmstat.h> |
34c0fd54 | 24 | #include <linux/pfn_t.h> |
0e749e54 | 25 | #include <linux/sizes.h> |
4b4bb46d | 26 | #include <linux/mmu_notifier.h> |
a254e568 | 27 | #include <linux/iomap.h> |
11cf9d86 | 28 | #include <asm/pgalloc.h> |
a254e568 | 29 | #include "internal.h" |
d475c634 | 30 | |
282a8e03 RZ |
31 | #define CREATE_TRACE_POINTS |
32 | #include <trace/events/fs_dax.h> | |
33 | ||
cfc93c6c MW |
34 | static inline unsigned int pe_order(enum page_entry_size pe_size) |
35 | { | |
36 | if (pe_size == PE_SIZE_PTE) | |
37 | return PAGE_SHIFT - PAGE_SHIFT; | |
38 | if (pe_size == PE_SIZE_PMD) | |
39 | return PMD_SHIFT - PAGE_SHIFT; | |
40 | if (pe_size == PE_SIZE_PUD) | |
41 | return PUD_SHIFT - PAGE_SHIFT; | |
42 | return ~0; | |
43 | } | |
44 | ||
ac401cc7 JK |
45 | /* We choose 4096 entries - same as per-zone page wait tables */ |
46 | #define DAX_WAIT_TABLE_BITS 12 | |
47 | #define DAX_WAIT_TABLE_ENTRIES (1 << DAX_WAIT_TABLE_BITS) | |
48 | ||
917f3452 RZ |
49 | /* The 'colour' (ie low bits) within a PMD of a page offset. */ |
50 | #define PG_PMD_COLOUR ((PMD_SIZE >> PAGE_SHIFT) - 1) | |
977fbdcd | 51 | #define PG_PMD_NR (PMD_SIZE >> PAGE_SHIFT) |
917f3452 | 52 | |
cfc93c6c MW |
53 | /* The order of a PMD entry */ |
54 | #define PMD_ORDER (PMD_SHIFT - PAGE_SHIFT) | |
55 | ||
ce95ab0f | 56 | static wait_queue_head_t wait_table[DAX_WAIT_TABLE_ENTRIES]; |
ac401cc7 JK |
57 | |
58 | static int __init init_dax_wait_table(void) | |
59 | { | |
60 | int i; | |
61 | ||
62 | for (i = 0; i < DAX_WAIT_TABLE_ENTRIES; i++) | |
63 | init_waitqueue_head(wait_table + i); | |
64 | return 0; | |
65 | } | |
66 | fs_initcall(init_dax_wait_table); | |
67 | ||
527b19d0 | 68 | /* |
3159f943 MW |
69 | * DAX pagecache entries use XArray value entries so they can't be mistaken |
70 | * for pages. We use one bit for locking, one bit for the entry size (PMD) | |
71 | * and two more to tell us if the entry is a zero page or an empty entry that | |
72 | * is just used for locking. In total four special bits. | |
527b19d0 RZ |
73 | * |
74 | * If the PMD bit isn't set the entry has size PAGE_SIZE, and if the ZERO_PAGE | |
75 | * and EMPTY bits aren't set the entry is a normal DAX entry with a filesystem | |
76 | * block allocation. | |
77 | */ | |
3159f943 MW |
78 | #define DAX_SHIFT (4) |
79 | #define DAX_LOCKED (1UL << 0) | |
80 | #define DAX_PMD (1UL << 1) | |
81 | #define DAX_ZERO_PAGE (1UL << 2) | |
82 | #define DAX_EMPTY (1UL << 3) | |
527b19d0 | 83 | |
a77d19f4 | 84 | static unsigned long dax_to_pfn(void *entry) |
527b19d0 | 85 | { |
3159f943 | 86 | return xa_to_value(entry) >> DAX_SHIFT; |
527b19d0 RZ |
87 | } |
88 | ||
9f32d221 MW |
89 | static void *dax_make_entry(pfn_t pfn, unsigned long flags) |
90 | { | |
91 | return xa_mk_value(flags | (pfn_t_to_pfn(pfn) << DAX_SHIFT)); | |
92 | } | |
93 | ||
cfc93c6c MW |
94 | static bool dax_is_locked(void *entry) |
95 | { | |
96 | return xa_to_value(entry) & DAX_LOCKED; | |
97 | } | |
98 | ||
a77d19f4 | 99 | static unsigned int dax_entry_order(void *entry) |
527b19d0 | 100 | { |
3159f943 | 101 | if (xa_to_value(entry) & DAX_PMD) |
cfc93c6c | 102 | return PMD_ORDER; |
527b19d0 RZ |
103 | return 0; |
104 | } | |
105 | ||
fda490d3 | 106 | static unsigned long dax_is_pmd_entry(void *entry) |
d1a5f2b4 | 107 | { |
3159f943 | 108 | return xa_to_value(entry) & DAX_PMD; |
d1a5f2b4 DW |
109 | } |
110 | ||
fda490d3 | 111 | static bool dax_is_pte_entry(void *entry) |
d475c634 | 112 | { |
3159f943 | 113 | return !(xa_to_value(entry) & DAX_PMD); |
d475c634 MW |
114 | } |
115 | ||
642261ac | 116 | static int dax_is_zero_entry(void *entry) |
d475c634 | 117 | { |
3159f943 | 118 | return xa_to_value(entry) & DAX_ZERO_PAGE; |
d475c634 MW |
119 | } |
120 | ||
642261ac | 121 | static int dax_is_empty_entry(void *entry) |
b2e0d162 | 122 | { |
3159f943 | 123 | return xa_to_value(entry) & DAX_EMPTY; |
b2e0d162 DW |
124 | } |
125 | ||
ac401cc7 | 126 | /* |
a77d19f4 | 127 | * DAX page cache entry locking |
ac401cc7 JK |
128 | */ |
129 | struct exceptional_entry_key { | |
ec4907ff | 130 | struct xarray *xa; |
63e95b5c | 131 | pgoff_t entry_start; |
ac401cc7 JK |
132 | }; |
133 | ||
134 | struct wait_exceptional_entry_queue { | |
ac6424b9 | 135 | wait_queue_entry_t wait; |
ac401cc7 JK |
136 | struct exceptional_entry_key key; |
137 | }; | |
138 | ||
b15cd800 MW |
139 | static wait_queue_head_t *dax_entry_waitqueue(struct xa_state *xas, |
140 | void *entry, struct exceptional_entry_key *key) | |
63e95b5c RZ |
141 | { |
142 | unsigned long hash; | |
b15cd800 | 143 | unsigned long index = xas->xa_index; |
63e95b5c RZ |
144 | |
145 | /* | |
146 | * If 'entry' is a PMD, align the 'index' that we use for the wait | |
147 | * queue to the start of that PMD. This ensures that all offsets in | |
148 | * the range covered by the PMD map to the same bit lock. | |
149 | */ | |
642261ac | 150 | if (dax_is_pmd_entry(entry)) |
917f3452 | 151 | index &= ~PG_PMD_COLOUR; |
b15cd800 | 152 | key->xa = xas->xa; |
63e95b5c RZ |
153 | key->entry_start = index; |
154 | ||
b15cd800 | 155 | hash = hash_long((unsigned long)xas->xa ^ index, DAX_WAIT_TABLE_BITS); |
63e95b5c RZ |
156 | return wait_table + hash; |
157 | } | |
158 | ||
ec4907ff MW |
159 | static int wake_exceptional_entry_func(wait_queue_entry_t *wait, |
160 | unsigned int mode, int sync, void *keyp) | |
ac401cc7 JK |
161 | { |
162 | struct exceptional_entry_key *key = keyp; | |
163 | struct wait_exceptional_entry_queue *ewait = | |
164 | container_of(wait, struct wait_exceptional_entry_queue, wait); | |
165 | ||
ec4907ff | 166 | if (key->xa != ewait->key.xa || |
63e95b5c | 167 | key->entry_start != ewait->key.entry_start) |
ac401cc7 JK |
168 | return 0; |
169 | return autoremove_wake_function(wait, mode, sync, NULL); | |
170 | } | |
171 | ||
e30331ff | 172 | /* |
b93b0163 MW |
173 | * @entry may no longer be the entry at the index in the mapping. |
174 | * The important information it's conveying is whether the entry at | |
175 | * this index used to be a PMD entry. | |
e30331ff | 176 | */ |
b15cd800 | 177 | static void dax_wake_entry(struct xa_state *xas, void *entry, bool wake_all) |
e30331ff RZ |
178 | { |
179 | struct exceptional_entry_key key; | |
180 | wait_queue_head_t *wq; | |
181 | ||
b15cd800 | 182 | wq = dax_entry_waitqueue(xas, entry, &key); |
e30331ff RZ |
183 | |
184 | /* | |
185 | * Checking for locked entry and prepare_to_wait_exclusive() happens | |
b93b0163 | 186 | * under the i_pages lock, ditto for entry handling in our callers. |
e30331ff RZ |
187 | * So at this point all tasks that could have seen our entry locked |
188 | * must be in the waitqueue and the following check will see them. | |
189 | */ | |
190 | if (waitqueue_active(wq)) | |
191 | __wake_up(wq, TASK_NORMAL, wake_all ? 0 : 1, &key); | |
192 | } | |
193 | ||
cfc93c6c MW |
194 | /* |
195 | * Look up entry in page cache, wait for it to become unlocked if it | |
196 | * is a DAX entry and return it. The caller must subsequently call | |
197 | * put_unlocked_entry() if it did not lock the entry or dax_unlock_entry() | |
198 | * if it did. | |
199 | * | |
200 | * Must be called with the i_pages lock held. | |
201 | */ | |
202 | static void *get_unlocked_entry(struct xa_state *xas) | |
203 | { | |
204 | void *entry; | |
205 | struct wait_exceptional_entry_queue ewait; | |
206 | wait_queue_head_t *wq; | |
207 | ||
208 | init_wait(&ewait.wait); | |
209 | ewait.wait.func = wake_exceptional_entry_func; | |
210 | ||
211 | for (;;) { | |
0e40de03 MW |
212 | entry = xas_find_conflict(xas); |
213 | if (!entry || WARN_ON_ONCE(!xa_is_value(entry)) || | |
cfc93c6c MW |
214 | !dax_is_locked(entry)) |
215 | return entry; | |
216 | ||
b15cd800 | 217 | wq = dax_entry_waitqueue(xas, entry, &ewait.key); |
cfc93c6c MW |
218 | prepare_to_wait_exclusive(wq, &ewait.wait, |
219 | TASK_UNINTERRUPTIBLE); | |
220 | xas_unlock_irq(xas); | |
221 | xas_reset(xas); | |
222 | schedule(); | |
223 | finish_wait(wq, &ewait.wait); | |
224 | xas_lock_irq(xas); | |
225 | } | |
226 | } | |
227 | ||
55e56f06 MW |
228 | /* |
229 | * The only thing keeping the address space around is the i_pages lock | |
230 | * (it's cycled in clear_inode() after removing the entries from i_pages) | |
231 | * After we call xas_unlock_irq(), we cannot touch xas->xa. | |
232 | */ | |
233 | static void wait_entry_unlocked(struct xa_state *xas, void *entry) | |
234 | { | |
235 | struct wait_exceptional_entry_queue ewait; | |
236 | wait_queue_head_t *wq; | |
237 | ||
238 | init_wait(&ewait.wait); | |
239 | ewait.wait.func = wake_exceptional_entry_func; | |
240 | ||
241 | wq = dax_entry_waitqueue(xas, entry, &ewait.key); | |
d8a70641 DW |
242 | /* |
243 | * Unlike get_unlocked_entry() there is no guarantee that this | |
244 | * path ever successfully retrieves an unlocked entry before an | |
245 | * inode dies. Perform a non-exclusive wait in case this path | |
246 | * never successfully performs its own wake up. | |
247 | */ | |
248 | prepare_to_wait(wq, &ewait.wait, TASK_UNINTERRUPTIBLE); | |
55e56f06 MW |
249 | xas_unlock_irq(xas); |
250 | schedule(); | |
251 | finish_wait(wq, &ewait.wait); | |
55e56f06 MW |
252 | } |
253 | ||
cfc93c6c MW |
254 | static void put_unlocked_entry(struct xa_state *xas, void *entry) |
255 | { | |
256 | /* If we were the only waiter woken, wake the next one */ | |
257 | if (entry) | |
258 | dax_wake_entry(xas, entry, false); | |
259 | } | |
260 | ||
261 | /* | |
262 | * We used the xa_state to get the entry, but then we locked the entry and | |
263 | * dropped the xa_lock, so we know the xa_state is stale and must be reset | |
264 | * before use. | |
265 | */ | |
266 | static void dax_unlock_entry(struct xa_state *xas, void *entry) | |
267 | { | |
268 | void *old; | |
269 | ||
7ae2ea7d | 270 | BUG_ON(dax_is_locked(entry)); |
cfc93c6c MW |
271 | xas_reset(xas); |
272 | xas_lock_irq(xas); | |
273 | old = xas_store(xas, entry); | |
274 | xas_unlock_irq(xas); | |
275 | BUG_ON(!dax_is_locked(old)); | |
276 | dax_wake_entry(xas, entry, false); | |
277 | } | |
278 | ||
279 | /* | |
280 | * Return: The entry stored at this location before it was locked. | |
281 | */ | |
282 | static void *dax_lock_entry(struct xa_state *xas, void *entry) | |
283 | { | |
284 | unsigned long v = xa_to_value(entry); | |
285 | return xas_store(xas, xa_mk_value(v | DAX_LOCKED)); | |
286 | } | |
287 | ||
d2c997c0 DW |
288 | static unsigned long dax_entry_size(void *entry) |
289 | { | |
290 | if (dax_is_zero_entry(entry)) | |
291 | return 0; | |
292 | else if (dax_is_empty_entry(entry)) | |
293 | return 0; | |
294 | else if (dax_is_pmd_entry(entry)) | |
295 | return PMD_SIZE; | |
296 | else | |
297 | return PAGE_SIZE; | |
298 | } | |
299 | ||
a77d19f4 | 300 | static unsigned long dax_end_pfn(void *entry) |
d2c997c0 | 301 | { |
a77d19f4 | 302 | return dax_to_pfn(entry) + dax_entry_size(entry) / PAGE_SIZE; |
d2c997c0 DW |
303 | } |
304 | ||
305 | /* | |
306 | * Iterate through all mapped pfns represented by an entry, i.e. skip | |
307 | * 'empty' and 'zero' entries. | |
308 | */ | |
309 | #define for_each_mapped_pfn(entry, pfn) \ | |
a77d19f4 MW |
310 | for (pfn = dax_to_pfn(entry); \ |
311 | pfn < dax_end_pfn(entry); pfn++) | |
d2c997c0 | 312 | |
73449daf DW |
313 | /* |
314 | * TODO: for reflink+dax we need a way to associate a single page with | |
315 | * multiple address_space instances at different linear_page_index() | |
316 | * offsets. | |
317 | */ | |
318 | static void dax_associate_entry(void *entry, struct address_space *mapping, | |
319 | struct vm_area_struct *vma, unsigned long address) | |
d2c997c0 | 320 | { |
73449daf DW |
321 | unsigned long size = dax_entry_size(entry), pfn, index; |
322 | int i = 0; | |
d2c997c0 DW |
323 | |
324 | if (IS_ENABLED(CONFIG_FS_DAX_LIMITED)) | |
325 | return; | |
326 | ||
73449daf | 327 | index = linear_page_index(vma, address & ~(size - 1)); |
d2c997c0 DW |
328 | for_each_mapped_pfn(entry, pfn) { |
329 | struct page *page = pfn_to_page(pfn); | |
330 | ||
331 | WARN_ON_ONCE(page->mapping); | |
332 | page->mapping = mapping; | |
73449daf | 333 | page->index = index + i++; |
d2c997c0 DW |
334 | } |
335 | } | |
336 | ||
337 | static void dax_disassociate_entry(void *entry, struct address_space *mapping, | |
338 | bool trunc) | |
339 | { | |
340 | unsigned long pfn; | |
341 | ||
342 | if (IS_ENABLED(CONFIG_FS_DAX_LIMITED)) | |
343 | return; | |
344 | ||
345 | for_each_mapped_pfn(entry, pfn) { | |
346 | struct page *page = pfn_to_page(pfn); | |
347 | ||
348 | WARN_ON_ONCE(trunc && page_ref_count(page) > 1); | |
349 | WARN_ON_ONCE(page->mapping && page->mapping != mapping); | |
350 | page->mapping = NULL; | |
73449daf | 351 | page->index = 0; |
d2c997c0 DW |
352 | } |
353 | } | |
354 | ||
5fac7408 DW |
355 | static struct page *dax_busy_page(void *entry) |
356 | { | |
357 | unsigned long pfn; | |
358 | ||
359 | for_each_mapped_pfn(entry, pfn) { | |
360 | struct page *page = pfn_to_page(pfn); | |
361 | ||
362 | if (page_ref_count(page) > 1) | |
363 | return page; | |
364 | } | |
365 | return NULL; | |
366 | } | |
367 | ||
c5bbd451 MW |
368 | /* |
369 | * dax_lock_mapping_entry - Lock the DAX entry corresponding to a page | |
370 | * @page: The page whose entry we want to lock | |
371 | * | |
372 | * Context: Process context. | |
27359fd6 MW |
373 | * Return: A cookie to pass to dax_unlock_page() or 0 if the entry could |
374 | * not be locked. | |
c5bbd451 | 375 | */ |
27359fd6 | 376 | dax_entry_t dax_lock_page(struct page *page) |
c2a7d2a1 | 377 | { |
9f32d221 MW |
378 | XA_STATE(xas, NULL, 0); |
379 | void *entry; | |
c2a7d2a1 | 380 | |
c5bbd451 MW |
381 | /* Ensure page->mapping isn't freed while we look at it */ |
382 | rcu_read_lock(); | |
c2a7d2a1 | 383 | for (;;) { |
9f32d221 | 384 | struct address_space *mapping = READ_ONCE(page->mapping); |
c2a7d2a1 | 385 | |
27359fd6 | 386 | entry = NULL; |
c93db7bb | 387 | if (!mapping || !dax_mapping(mapping)) |
c5bbd451 | 388 | break; |
c2a7d2a1 DW |
389 | |
390 | /* | |
391 | * In the device-dax case there's no need to lock, a | |
392 | * struct dev_pagemap pin is sufficient to keep the | |
393 | * inode alive, and we assume we have dev_pagemap pin | |
394 | * otherwise we would not have a valid pfn_to_page() | |
395 | * translation. | |
396 | */ | |
27359fd6 | 397 | entry = (void *)~0UL; |
9f32d221 | 398 | if (S_ISCHR(mapping->host->i_mode)) |
c5bbd451 | 399 | break; |
c2a7d2a1 | 400 | |
9f32d221 MW |
401 | xas.xa = &mapping->i_pages; |
402 | xas_lock_irq(&xas); | |
c2a7d2a1 | 403 | if (mapping != page->mapping) { |
9f32d221 | 404 | xas_unlock_irq(&xas); |
c2a7d2a1 DW |
405 | continue; |
406 | } | |
9f32d221 MW |
407 | xas_set(&xas, page->index); |
408 | entry = xas_load(&xas); | |
409 | if (dax_is_locked(entry)) { | |
c5bbd451 | 410 | rcu_read_unlock(); |
55e56f06 | 411 | wait_entry_unlocked(&xas, entry); |
c5bbd451 | 412 | rcu_read_lock(); |
6d7cd8c1 | 413 | continue; |
c2a7d2a1 | 414 | } |
9f32d221 MW |
415 | dax_lock_entry(&xas, entry); |
416 | xas_unlock_irq(&xas); | |
c5bbd451 | 417 | break; |
c2a7d2a1 | 418 | } |
c5bbd451 | 419 | rcu_read_unlock(); |
27359fd6 | 420 | return (dax_entry_t)entry; |
c2a7d2a1 DW |
421 | } |
422 | ||
27359fd6 | 423 | void dax_unlock_page(struct page *page, dax_entry_t cookie) |
c2a7d2a1 DW |
424 | { |
425 | struct address_space *mapping = page->mapping; | |
9f32d221 | 426 | XA_STATE(xas, &mapping->i_pages, page->index); |
c2a7d2a1 | 427 | |
9f32d221 | 428 | if (S_ISCHR(mapping->host->i_mode)) |
c2a7d2a1 DW |
429 | return; |
430 | ||
27359fd6 | 431 | dax_unlock_entry(&xas, (void *)cookie); |
c2a7d2a1 DW |
432 | } |
433 | ||
ac401cc7 | 434 | /* |
a77d19f4 MW |
435 | * Find page cache entry at given index. If it is a DAX entry, return it |
436 | * with the entry locked. If the page cache doesn't contain an entry at | |
437 | * that index, add a locked empty entry. | |
ac401cc7 | 438 | * |
3159f943 | 439 | * When requesting an entry with size DAX_PMD, grab_mapping_entry() will |
b15cd800 MW |
440 | * either return that locked entry or will return VM_FAULT_FALLBACK. |
441 | * This will happen if there are any PTE entries within the PMD range | |
442 | * that we are requesting. | |
642261ac | 443 | * |
b15cd800 MW |
444 | * We always favor PTE entries over PMD entries. There isn't a flow where we |
445 | * evict PTE entries in order to 'upgrade' them to a PMD entry. A PMD | |
446 | * insertion will fail if it finds any PTE entries already in the tree, and a | |
447 | * PTE insertion will cause an existing PMD entry to be unmapped and | |
448 | * downgraded to PTE entries. This happens for both PMD zero pages as | |
449 | * well as PMD empty entries. | |
642261ac | 450 | * |
b15cd800 MW |
451 | * The exception to this downgrade path is for PMD entries that have |
452 | * real storage backing them. We will leave these real PMD entries in | |
453 | * the tree, and PTE writes will simply dirty the entire PMD entry. | |
642261ac | 454 | * |
ac401cc7 JK |
455 | * Note: Unlike filemap_fault() we don't honor FAULT_FLAG_RETRY flags. For |
456 | * persistent memory the benefit is doubtful. We can add that later if we can | |
457 | * show it helps. | |
b15cd800 MW |
458 | * |
459 | * On error, this function does not return an ERR_PTR. Instead it returns | |
460 | * a VM_FAULT code, encoded as an xarray internal entry. The ERR_PTR values | |
461 | * overlap with xarray value entries. | |
ac401cc7 | 462 | */ |
b15cd800 MW |
463 | static void *grab_mapping_entry(struct xa_state *xas, |
464 | struct address_space *mapping, unsigned long size_flag) | |
ac401cc7 | 465 | { |
b15cd800 MW |
466 | unsigned long index = xas->xa_index; |
467 | bool pmd_downgrade = false; /* splitting PMD entry into PTE entries? */ | |
468 | void *entry; | |
642261ac | 469 | |
b15cd800 MW |
470 | retry: |
471 | xas_lock_irq(xas); | |
472 | entry = get_unlocked_entry(xas); | |
91d25ba8 | 473 | |
642261ac | 474 | if (entry) { |
0e40de03 | 475 | if (!xa_is_value(entry)) { |
b15cd800 MW |
476 | xas_set_err(xas, EIO); |
477 | goto out_unlock; | |
478 | } | |
479 | ||
3159f943 | 480 | if (size_flag & DAX_PMD) { |
91d25ba8 | 481 | if (dax_is_pte_entry(entry)) { |
b15cd800 MW |
482 | put_unlocked_entry(xas, entry); |
483 | goto fallback; | |
642261ac RZ |
484 | } |
485 | } else { /* trying to grab a PTE entry */ | |
91d25ba8 | 486 | if (dax_is_pmd_entry(entry) && |
642261ac RZ |
487 | (dax_is_zero_entry(entry) || |
488 | dax_is_empty_entry(entry))) { | |
489 | pmd_downgrade = true; | |
490 | } | |
491 | } | |
492 | } | |
493 | ||
b15cd800 MW |
494 | if (pmd_downgrade) { |
495 | /* | |
496 | * Make sure 'entry' remains valid while we drop | |
497 | * the i_pages lock. | |
498 | */ | |
499 | dax_lock_entry(xas, entry); | |
642261ac | 500 | |
642261ac RZ |
501 | /* |
502 | * Besides huge zero pages the only other thing that gets | |
503 | * downgraded are empty entries which don't need to be | |
504 | * unmapped. | |
505 | */ | |
b15cd800 MW |
506 | if (dax_is_zero_entry(entry)) { |
507 | xas_unlock_irq(xas); | |
508 | unmap_mapping_pages(mapping, | |
509 | xas->xa_index & ~PG_PMD_COLOUR, | |
510 | PG_PMD_NR, false); | |
511 | xas_reset(xas); | |
512 | xas_lock_irq(xas); | |
e11f8b7b RZ |
513 | } |
514 | ||
b15cd800 MW |
515 | dax_disassociate_entry(entry, mapping, false); |
516 | xas_store(xas, NULL); /* undo the PMD join */ | |
517 | dax_wake_entry(xas, entry, true); | |
518 | mapping->nrexceptional--; | |
519 | entry = NULL; | |
520 | xas_set(xas, index); | |
521 | } | |
642261ac | 522 | |
b15cd800 MW |
523 | if (entry) { |
524 | dax_lock_entry(xas, entry); | |
525 | } else { | |
526 | entry = dax_make_entry(pfn_to_pfn_t(0), size_flag | DAX_EMPTY); | |
527 | dax_lock_entry(xas, entry); | |
528 | if (xas_error(xas)) | |
529 | goto out_unlock; | |
ac401cc7 | 530 | mapping->nrexceptional++; |
ac401cc7 | 531 | } |
b15cd800 MW |
532 | |
533 | out_unlock: | |
534 | xas_unlock_irq(xas); | |
535 | if (xas_nomem(xas, mapping_gfp_mask(mapping) & ~__GFP_HIGHMEM)) | |
536 | goto retry; | |
537 | if (xas->xa_node == XA_ERROR(-ENOMEM)) | |
538 | return xa_mk_internal(VM_FAULT_OOM); | |
539 | if (xas_error(xas)) | |
540 | return xa_mk_internal(VM_FAULT_SIGBUS); | |
e3ad61c6 | 541 | return entry; |
b15cd800 MW |
542 | fallback: |
543 | xas_unlock_irq(xas); | |
544 | return xa_mk_internal(VM_FAULT_FALLBACK); | |
ac401cc7 JK |
545 | } |
546 | ||
5fac7408 DW |
547 | /** |
548 | * dax_layout_busy_page - find first pinned page in @mapping | |
549 | * @mapping: address space to scan for a page with ref count > 1 | |
550 | * | |
551 | * DAX requires ZONE_DEVICE mapped pages. These pages are never | |
552 | * 'onlined' to the page allocator so they are considered idle when | |
553 | * page->count == 1. A filesystem uses this interface to determine if | |
554 | * any page in the mapping is busy, i.e. for DMA, or other | |
555 | * get_user_pages() usages. | |
556 | * | |
557 | * It is expected that the filesystem is holding locks to block the | |
558 | * establishment of new mappings in this address_space. I.e. it expects | |
559 | * to be able to run unmap_mapping_range() and subsequently not race | |
560 | * mapping_mapped() becoming true. | |
561 | */ | |
562 | struct page *dax_layout_busy_page(struct address_space *mapping) | |
563 | { | |
084a8990 MW |
564 | XA_STATE(xas, &mapping->i_pages, 0); |
565 | void *entry; | |
566 | unsigned int scanned = 0; | |
5fac7408 | 567 | struct page *page = NULL; |
5fac7408 DW |
568 | |
569 | /* | |
570 | * In the 'limited' case get_user_pages() for dax is disabled. | |
571 | */ | |
572 | if (IS_ENABLED(CONFIG_FS_DAX_LIMITED)) | |
573 | return NULL; | |
574 | ||
575 | if (!dax_mapping(mapping) || !mapping_mapped(mapping)) | |
576 | return NULL; | |
577 | ||
5fac7408 DW |
578 | /* |
579 | * If we race get_user_pages_fast() here either we'll see the | |
084a8990 | 580 | * elevated page count in the iteration and wait, or |
5fac7408 DW |
581 | * get_user_pages_fast() will see that the page it took a reference |
582 | * against is no longer mapped in the page tables and bail to the | |
583 | * get_user_pages() slow path. The slow path is protected by | |
584 | * pte_lock() and pmd_lock(). New references are not taken without | |
585 | * holding those locks, and unmap_mapping_range() will not zero the | |
586 | * pte or pmd without holding the respective lock, so we are | |
587 | * guaranteed to either see new references or prevent new | |
588 | * references from being established. | |
589 | */ | |
590 | unmap_mapping_range(mapping, 0, 0, 1); | |
591 | ||
084a8990 MW |
592 | xas_lock_irq(&xas); |
593 | xas_for_each(&xas, entry, ULONG_MAX) { | |
594 | if (WARN_ON_ONCE(!xa_is_value(entry))) | |
595 | continue; | |
596 | if (unlikely(dax_is_locked(entry))) | |
597 | entry = get_unlocked_entry(&xas); | |
598 | if (entry) | |
599 | page = dax_busy_page(entry); | |
600 | put_unlocked_entry(&xas, entry); | |
5fac7408 DW |
601 | if (page) |
602 | break; | |
084a8990 MW |
603 | if (++scanned % XA_CHECK_SCHED) |
604 | continue; | |
605 | ||
606 | xas_pause(&xas); | |
607 | xas_unlock_irq(&xas); | |
608 | cond_resched(); | |
609 | xas_lock_irq(&xas); | |
5fac7408 | 610 | } |
084a8990 | 611 | xas_unlock_irq(&xas); |
5fac7408 DW |
612 | return page; |
613 | } | |
614 | EXPORT_SYMBOL_GPL(dax_layout_busy_page); | |
615 | ||
a77d19f4 | 616 | static int __dax_invalidate_entry(struct address_space *mapping, |
c6dcf52c JK |
617 | pgoff_t index, bool trunc) |
618 | { | |
07f2d89c | 619 | XA_STATE(xas, &mapping->i_pages, index); |
c6dcf52c JK |
620 | int ret = 0; |
621 | void *entry; | |
c6dcf52c | 622 | |
07f2d89c MW |
623 | xas_lock_irq(&xas); |
624 | entry = get_unlocked_entry(&xas); | |
3159f943 | 625 | if (!entry || WARN_ON_ONCE(!xa_is_value(entry))) |
c6dcf52c JK |
626 | goto out; |
627 | if (!trunc && | |
07f2d89c MW |
628 | (xas_get_mark(&xas, PAGECACHE_TAG_DIRTY) || |
629 | xas_get_mark(&xas, PAGECACHE_TAG_TOWRITE))) | |
c6dcf52c | 630 | goto out; |
d2c997c0 | 631 | dax_disassociate_entry(entry, mapping, trunc); |
07f2d89c | 632 | xas_store(&xas, NULL); |
c6dcf52c JK |
633 | mapping->nrexceptional--; |
634 | ret = 1; | |
635 | out: | |
07f2d89c MW |
636 | put_unlocked_entry(&xas, entry); |
637 | xas_unlock_irq(&xas); | |
c6dcf52c JK |
638 | return ret; |
639 | } | |
07f2d89c | 640 | |
ac401cc7 | 641 | /* |
3159f943 MW |
642 | * Delete DAX entry at @index from @mapping. Wait for it |
643 | * to be unlocked before deleting it. | |
ac401cc7 JK |
644 | */ |
645 | int dax_delete_mapping_entry(struct address_space *mapping, pgoff_t index) | |
646 | { | |
a77d19f4 | 647 | int ret = __dax_invalidate_entry(mapping, index, true); |
ac401cc7 | 648 | |
ac401cc7 JK |
649 | /* |
650 | * This gets called from truncate / punch_hole path. As such, the caller | |
651 | * must hold locks protecting against concurrent modifications of the | |
a77d19f4 | 652 | * page cache (usually fs-private i_mmap_sem for writing). Since the |
3159f943 | 653 | * caller has seen a DAX entry for this index, we better find it |
ac401cc7 JK |
654 | * at that index as well... |
655 | */ | |
c6dcf52c JK |
656 | WARN_ON_ONCE(!ret); |
657 | return ret; | |
658 | } | |
659 | ||
c6dcf52c | 660 | /* |
3159f943 | 661 | * Invalidate DAX entry if it is clean. |
c6dcf52c JK |
662 | */ |
663 | int dax_invalidate_mapping_entry_sync(struct address_space *mapping, | |
664 | pgoff_t index) | |
665 | { | |
a77d19f4 | 666 | return __dax_invalidate_entry(mapping, index, false); |
ac401cc7 JK |
667 | } |
668 | ||
cccbce67 DW |
669 | static int copy_user_dax(struct block_device *bdev, struct dax_device *dax_dev, |
670 | sector_t sector, size_t size, struct page *to, | |
671 | unsigned long vaddr) | |
f7ca90b1 | 672 | { |
cccbce67 DW |
673 | void *vto, *kaddr; |
674 | pgoff_t pgoff; | |
cccbce67 DW |
675 | long rc; |
676 | int id; | |
677 | ||
678 | rc = bdev_dax_pgoff(bdev, sector, size, &pgoff); | |
679 | if (rc) | |
680 | return rc; | |
681 | ||
682 | id = dax_read_lock(); | |
86ed913b | 683 | rc = dax_direct_access(dax_dev, pgoff, PHYS_PFN(size), &kaddr, NULL); |
cccbce67 DW |
684 | if (rc < 0) { |
685 | dax_read_unlock(id); | |
686 | return rc; | |
687 | } | |
f7ca90b1 | 688 | vto = kmap_atomic(to); |
cccbce67 | 689 | copy_user_page(vto, (void __force *)kaddr, vaddr, to); |
f7ca90b1 | 690 | kunmap_atomic(vto); |
cccbce67 | 691 | dax_read_unlock(id); |
f7ca90b1 MW |
692 | return 0; |
693 | } | |
694 | ||
642261ac RZ |
695 | /* |
696 | * By this point grab_mapping_entry() has ensured that we have a locked entry | |
697 | * of the appropriate size so we don't have to worry about downgrading PMDs to | |
698 | * PTEs. If we happen to be trying to insert a PTE and there is a PMD | |
699 | * already in the tree, we will skip the insertion and just dirty the PMD as | |
700 | * appropriate. | |
701 | */ | |
b15cd800 MW |
702 | static void *dax_insert_entry(struct xa_state *xas, |
703 | struct address_space *mapping, struct vm_fault *vmf, | |
704 | void *entry, pfn_t pfn, unsigned long flags, bool dirty) | |
9973c98e | 705 | { |
b15cd800 | 706 | void *new_entry = dax_make_entry(pfn, flags); |
9973c98e | 707 | |
f5b7b748 | 708 | if (dirty) |
d2b2a28e | 709 | __mark_inode_dirty(mapping->host, I_DIRTY_PAGES); |
9973c98e | 710 | |
3159f943 | 711 | if (dax_is_zero_entry(entry) && !(flags & DAX_ZERO_PAGE)) { |
b15cd800 | 712 | unsigned long index = xas->xa_index; |
91d25ba8 RZ |
713 | /* we are replacing a zero page with block mapping */ |
714 | if (dax_is_pmd_entry(entry)) | |
977fbdcd | 715 | unmap_mapping_pages(mapping, index & ~PG_PMD_COLOUR, |
b15cd800 | 716 | PG_PMD_NR, false); |
91d25ba8 | 717 | else /* pte entry */ |
b15cd800 | 718 | unmap_mapping_pages(mapping, index, 1, false); |
9973c98e RZ |
719 | } |
720 | ||
b15cd800 MW |
721 | xas_reset(xas); |
722 | xas_lock_irq(xas); | |
1571c029 JK |
723 | if (dax_is_zero_entry(entry) || dax_is_empty_entry(entry)) { |
724 | void *old; | |
725 | ||
d2c997c0 | 726 | dax_disassociate_entry(entry, mapping, false); |
73449daf | 727 | dax_associate_entry(new_entry, mapping, vmf->vma, vmf->address); |
642261ac | 728 | /* |
a77d19f4 | 729 | * Only swap our new entry into the page cache if the current |
642261ac | 730 | * entry is a zero page or an empty entry. If a normal PTE or |
a77d19f4 | 731 | * PMD entry is already in the cache, we leave it alone. This |
642261ac RZ |
732 | * means that if we are trying to insert a PTE and the |
733 | * existing entry is a PMD, we will just leave the PMD in the | |
734 | * tree and dirty it if necessary. | |
735 | */ | |
1571c029 | 736 | old = dax_lock_entry(xas, new_entry); |
b15cd800 MW |
737 | WARN_ON_ONCE(old != xa_mk_value(xa_to_value(entry) | |
738 | DAX_LOCKED)); | |
91d25ba8 | 739 | entry = new_entry; |
b15cd800 MW |
740 | } else { |
741 | xas_load(xas); /* Walk the xa_state */ | |
9973c98e | 742 | } |
91d25ba8 | 743 | |
f5b7b748 | 744 | if (dirty) |
b15cd800 | 745 | xas_set_mark(xas, PAGECACHE_TAG_DIRTY); |
91d25ba8 | 746 | |
b15cd800 | 747 | xas_unlock_irq(xas); |
91d25ba8 | 748 | return entry; |
9973c98e RZ |
749 | } |
750 | ||
a77d19f4 MW |
751 | static inline |
752 | unsigned long pgoff_address(pgoff_t pgoff, struct vm_area_struct *vma) | |
4b4bb46d JK |
753 | { |
754 | unsigned long address; | |
755 | ||
756 | address = vma->vm_start + ((pgoff - vma->vm_pgoff) << PAGE_SHIFT); | |
757 | VM_BUG_ON_VMA(address < vma->vm_start || address >= vma->vm_end, vma); | |
758 | return address; | |
759 | } | |
760 | ||
761 | /* Walk all mappings of a given index of a file and writeprotect them */ | |
a77d19f4 MW |
762 | static void dax_entry_mkclean(struct address_space *mapping, pgoff_t index, |
763 | unsigned long pfn) | |
4b4bb46d JK |
764 | { |
765 | struct vm_area_struct *vma; | |
f729c8c9 RZ |
766 | pte_t pte, *ptep = NULL; |
767 | pmd_t *pmdp = NULL; | |
4b4bb46d | 768 | spinlock_t *ptl; |
4b4bb46d JK |
769 | |
770 | i_mmap_lock_read(mapping); | |
771 | vma_interval_tree_foreach(vma, &mapping->i_mmap, index, index) { | |
ac46d4f3 JG |
772 | struct mmu_notifier_range range; |
773 | unsigned long address; | |
4b4bb46d JK |
774 | |
775 | cond_resched(); | |
776 | ||
777 | if (!(vma->vm_flags & VM_SHARED)) | |
778 | continue; | |
779 | ||
780 | address = pgoff_address(index, vma); | |
a4d1a885 JG |
781 | |
782 | /* | |
0cefc36b | 783 | * Note because we provide range to follow_pte_pmd it will |
a4d1a885 JG |
784 | * call mmu_notifier_invalidate_range_start() on our behalf |
785 | * before taking any lock. | |
786 | */ | |
ac46d4f3 JG |
787 | if (follow_pte_pmd(vma->vm_mm, address, &range, |
788 | &ptep, &pmdp, &ptl)) | |
4b4bb46d | 789 | continue; |
4b4bb46d | 790 | |
0f10851e JG |
791 | /* |
792 | * No need to call mmu_notifier_invalidate_range() as we are | |
793 | * downgrading page table protection not changing it to point | |
794 | * to a new page. | |
795 | * | |
ad56b738 | 796 | * See Documentation/vm/mmu_notifier.rst |
0f10851e | 797 | */ |
f729c8c9 RZ |
798 | if (pmdp) { |
799 | #ifdef CONFIG_FS_DAX_PMD | |
800 | pmd_t pmd; | |
801 | ||
802 | if (pfn != pmd_pfn(*pmdp)) | |
803 | goto unlock_pmd; | |
f6f37321 | 804 | if (!pmd_dirty(*pmdp) && !pmd_write(*pmdp)) |
f729c8c9 RZ |
805 | goto unlock_pmd; |
806 | ||
807 | flush_cache_page(vma, address, pfn); | |
024eee0e | 808 | pmd = pmdp_invalidate(vma, address, pmdp); |
f729c8c9 RZ |
809 | pmd = pmd_wrprotect(pmd); |
810 | pmd = pmd_mkclean(pmd); | |
811 | set_pmd_at(vma->vm_mm, address, pmdp, pmd); | |
f729c8c9 | 812 | unlock_pmd: |
f729c8c9 | 813 | #endif |
ee190ca6 | 814 | spin_unlock(ptl); |
f729c8c9 RZ |
815 | } else { |
816 | if (pfn != pte_pfn(*ptep)) | |
817 | goto unlock_pte; | |
818 | if (!pte_dirty(*ptep) && !pte_write(*ptep)) | |
819 | goto unlock_pte; | |
820 | ||
821 | flush_cache_page(vma, address, pfn); | |
822 | pte = ptep_clear_flush(vma, address, ptep); | |
823 | pte = pte_wrprotect(pte); | |
824 | pte = pte_mkclean(pte); | |
825 | set_pte_at(vma->vm_mm, address, ptep, pte); | |
f729c8c9 RZ |
826 | unlock_pte: |
827 | pte_unmap_unlock(ptep, ptl); | |
828 | } | |
4b4bb46d | 829 | |
ac46d4f3 | 830 | mmu_notifier_invalidate_range_end(&range); |
4b4bb46d JK |
831 | } |
832 | i_mmap_unlock_read(mapping); | |
833 | } | |
834 | ||
9fc747f6 MW |
835 | static int dax_writeback_one(struct xa_state *xas, struct dax_device *dax_dev, |
836 | struct address_space *mapping, void *entry) | |
9973c98e | 837 | { |
e4b3448b | 838 | unsigned long pfn, index, count; |
3fe0791c | 839 | long ret = 0; |
9973c98e | 840 | |
9973c98e | 841 | /* |
a6abc2c0 JK |
842 | * A page got tagged dirty in DAX mapping? Something is seriously |
843 | * wrong. | |
9973c98e | 844 | */ |
3159f943 | 845 | if (WARN_ON(!xa_is_value(entry))) |
a6abc2c0 | 846 | return -EIO; |
9973c98e | 847 | |
9fc747f6 MW |
848 | if (unlikely(dax_is_locked(entry))) { |
849 | void *old_entry = entry; | |
850 | ||
851 | entry = get_unlocked_entry(xas); | |
852 | ||
853 | /* Entry got punched out / reallocated? */ | |
854 | if (!entry || WARN_ON_ONCE(!xa_is_value(entry))) | |
855 | goto put_unlocked; | |
856 | /* | |
857 | * Entry got reallocated elsewhere? No need to writeback. | |
858 | * We have to compare pfns as we must not bail out due to | |
859 | * difference in lockbit or entry type. | |
860 | */ | |
861 | if (dax_to_pfn(old_entry) != dax_to_pfn(entry)) | |
862 | goto put_unlocked; | |
863 | if (WARN_ON_ONCE(dax_is_empty_entry(entry) || | |
864 | dax_is_zero_entry(entry))) { | |
865 | ret = -EIO; | |
866 | goto put_unlocked; | |
867 | } | |
868 | ||
869 | /* Another fsync thread may have already done this entry */ | |
870 | if (!xas_get_mark(xas, PAGECACHE_TAG_TOWRITE)) | |
871 | goto put_unlocked; | |
9973c98e RZ |
872 | } |
873 | ||
a6abc2c0 | 874 | /* Lock the entry to serialize with page faults */ |
9fc747f6 MW |
875 | dax_lock_entry(xas, entry); |
876 | ||
a6abc2c0 JK |
877 | /* |
878 | * We can clear the tag now but we have to be careful so that concurrent | |
879 | * dax_writeback_one() calls for the same index cannot finish before we | |
880 | * actually flush the caches. This is achieved as the calls will look | |
b93b0163 MW |
881 | * at the entry only under the i_pages lock and once they do that |
882 | * they will see the entry locked and wait for it to unlock. | |
a6abc2c0 | 883 | */ |
9fc747f6 MW |
884 | xas_clear_mark(xas, PAGECACHE_TAG_TOWRITE); |
885 | xas_unlock_irq(xas); | |
a6abc2c0 | 886 | |
642261ac | 887 | /* |
e4b3448b MW |
888 | * If dax_writeback_mapping_range() was given a wbc->range_start |
889 | * in the middle of a PMD, the 'index' we use needs to be | |
890 | * aligned to the start of the PMD. | |
3fe0791c DW |
891 | * This allows us to flush for PMD_SIZE and not have to worry about |
892 | * partial PMD writebacks. | |
642261ac | 893 | */ |
a77d19f4 | 894 | pfn = dax_to_pfn(entry); |
e4b3448b MW |
895 | count = 1UL << dax_entry_order(entry); |
896 | index = xas->xa_index & ~(count - 1); | |
cccbce67 | 897 | |
e4b3448b MW |
898 | dax_entry_mkclean(mapping, index, pfn); |
899 | dax_flush(dax_dev, page_address(pfn_to_page(pfn)), count * PAGE_SIZE); | |
4b4bb46d JK |
900 | /* |
901 | * After we have flushed the cache, we can clear the dirty tag. There | |
902 | * cannot be new dirty data in the pfn after the flush has completed as | |
903 | * the pfn mappings are writeprotected and fault waits for mapping | |
904 | * entry lock. | |
905 | */ | |
9fc747f6 MW |
906 | xas_reset(xas); |
907 | xas_lock_irq(xas); | |
908 | xas_store(xas, entry); | |
909 | xas_clear_mark(xas, PAGECACHE_TAG_DIRTY); | |
910 | dax_wake_entry(xas, entry, false); | |
911 | ||
e4b3448b | 912 | trace_dax_writeback_one(mapping->host, index, count); |
9973c98e RZ |
913 | return ret; |
914 | ||
a6abc2c0 | 915 | put_unlocked: |
9fc747f6 | 916 | put_unlocked_entry(xas, entry); |
9973c98e RZ |
917 | return ret; |
918 | } | |
919 | ||
920 | /* | |
921 | * Flush the mapping to the persistent domain within the byte range of [start, | |
922 | * end]. This is required by data integrity operations to ensure file data is | |
923 | * on persistent storage prior to completion of the operation. | |
924 | */ | |
7f6d5b52 RZ |
925 | int dax_writeback_mapping_range(struct address_space *mapping, |
926 | struct block_device *bdev, struct writeback_control *wbc) | |
9973c98e | 927 | { |
9fc747f6 | 928 | XA_STATE(xas, &mapping->i_pages, wbc->range_start >> PAGE_SHIFT); |
9973c98e | 929 | struct inode *inode = mapping->host; |
9fc747f6 | 930 | pgoff_t end_index = wbc->range_end >> PAGE_SHIFT; |
cccbce67 | 931 | struct dax_device *dax_dev; |
9fc747f6 MW |
932 | void *entry; |
933 | int ret = 0; | |
934 | unsigned int scanned = 0; | |
9973c98e RZ |
935 | |
936 | if (WARN_ON_ONCE(inode->i_blkbits != PAGE_SHIFT)) | |
937 | return -EIO; | |
938 | ||
7f6d5b52 RZ |
939 | if (!mapping->nrexceptional || wbc->sync_mode != WB_SYNC_ALL) |
940 | return 0; | |
941 | ||
cccbce67 DW |
942 | dax_dev = dax_get_by_host(bdev->bd_disk->disk_name); |
943 | if (!dax_dev) | |
944 | return -EIO; | |
945 | ||
9fc747f6 | 946 | trace_dax_writeback_range(inode, xas.xa_index, end_index); |
9973c98e | 947 | |
9fc747f6 | 948 | tag_pages_for_writeback(mapping, xas.xa_index, end_index); |
9973c98e | 949 | |
9fc747f6 MW |
950 | xas_lock_irq(&xas); |
951 | xas_for_each_marked(&xas, entry, end_index, PAGECACHE_TAG_TOWRITE) { | |
952 | ret = dax_writeback_one(&xas, dax_dev, mapping, entry); | |
953 | if (ret < 0) { | |
954 | mapping_set_error(mapping, ret); | |
9973c98e | 955 | break; |
9973c98e | 956 | } |
9fc747f6 MW |
957 | if (++scanned % XA_CHECK_SCHED) |
958 | continue; | |
959 | ||
960 | xas_pause(&xas); | |
961 | xas_unlock_irq(&xas); | |
962 | cond_resched(); | |
963 | xas_lock_irq(&xas); | |
9973c98e | 964 | } |
9fc747f6 | 965 | xas_unlock_irq(&xas); |
cccbce67 | 966 | put_dax(dax_dev); |
9fc747f6 MW |
967 | trace_dax_writeback_range_done(inode, xas.xa_index, end_index); |
968 | return ret; | |
9973c98e RZ |
969 | } |
970 | EXPORT_SYMBOL_GPL(dax_writeback_mapping_range); | |
971 | ||
31a6f1a6 | 972 | static sector_t dax_iomap_sector(struct iomap *iomap, loff_t pos) |
f7ca90b1 | 973 | { |
a3841f94 | 974 | return (iomap->addr + (pos & PAGE_MASK) - iomap->offset) >> 9; |
31a6f1a6 JK |
975 | } |
976 | ||
5e161e40 JK |
977 | static int dax_iomap_pfn(struct iomap *iomap, loff_t pos, size_t size, |
978 | pfn_t *pfnp) | |
f7ca90b1 | 979 | { |
31a6f1a6 | 980 | const sector_t sector = dax_iomap_sector(iomap, pos); |
cccbce67 DW |
981 | pgoff_t pgoff; |
982 | int id, rc; | |
5e161e40 | 983 | long length; |
f7ca90b1 | 984 | |
5e161e40 | 985 | rc = bdev_dax_pgoff(iomap->bdev, sector, size, &pgoff); |
cccbce67 DW |
986 | if (rc) |
987 | return rc; | |
cccbce67 | 988 | id = dax_read_lock(); |
5e161e40 | 989 | length = dax_direct_access(iomap->dax_dev, pgoff, PHYS_PFN(size), |
86ed913b | 990 | NULL, pfnp); |
5e161e40 JK |
991 | if (length < 0) { |
992 | rc = length; | |
993 | goto out; | |
cccbce67 | 994 | } |
5e161e40 JK |
995 | rc = -EINVAL; |
996 | if (PFN_PHYS(length) < size) | |
997 | goto out; | |
998 | if (pfn_t_to_pfn(*pfnp) & (PHYS_PFN(size)-1)) | |
999 | goto out; | |
1000 | /* For larger pages we need devmap */ | |
1001 | if (length > 1 && !pfn_t_devmap(*pfnp)) | |
1002 | goto out; | |
1003 | rc = 0; | |
1004 | out: | |
cccbce67 | 1005 | dax_read_unlock(id); |
5e161e40 | 1006 | return rc; |
0e3b210c | 1007 | } |
0e3b210c | 1008 | |
e30331ff | 1009 | /* |
91d25ba8 RZ |
1010 | * The user has performed a load from a hole in the file. Allocating a new |
1011 | * page in the file would cause excessive storage usage for workloads with | |
1012 | * sparse files. Instead we insert a read-only mapping of the 4k zero page. | |
1013 | * If this page is ever written to we will re-fault and change the mapping to | |
1014 | * point to real DAX storage instead. | |
e30331ff | 1015 | */ |
b15cd800 MW |
1016 | static vm_fault_t dax_load_hole(struct xa_state *xas, |
1017 | struct address_space *mapping, void **entry, | |
1018 | struct vm_fault *vmf) | |
e30331ff RZ |
1019 | { |
1020 | struct inode *inode = mapping->host; | |
91d25ba8 | 1021 | unsigned long vaddr = vmf->address; |
b90ca5cc MW |
1022 | pfn_t pfn = pfn_to_pfn_t(my_zero_pfn(vaddr)); |
1023 | vm_fault_t ret; | |
e30331ff | 1024 | |
b15cd800 | 1025 | *entry = dax_insert_entry(xas, mapping, vmf, *entry, pfn, |
3159f943 MW |
1026 | DAX_ZERO_PAGE, false); |
1027 | ||
ab77dab4 | 1028 | ret = vmf_insert_mixed(vmf->vma, vaddr, pfn); |
e30331ff RZ |
1029 | trace_dax_load_hole(inode, vmf, ret); |
1030 | return ret; | |
1031 | } | |
1032 | ||
4b0228fa VV |
1033 | static bool dax_range_is_aligned(struct block_device *bdev, |
1034 | unsigned int offset, unsigned int length) | |
1035 | { | |
1036 | unsigned short sector_size = bdev_logical_block_size(bdev); | |
1037 | ||
1038 | if (!IS_ALIGNED(offset, sector_size)) | |
1039 | return false; | |
1040 | if (!IS_ALIGNED(length, sector_size)) | |
1041 | return false; | |
1042 | ||
1043 | return true; | |
1044 | } | |
1045 | ||
cccbce67 DW |
1046 | int __dax_zero_page_range(struct block_device *bdev, |
1047 | struct dax_device *dax_dev, sector_t sector, | |
1048 | unsigned int offset, unsigned int size) | |
679c8bd3 | 1049 | { |
cccbce67 DW |
1050 | if (dax_range_is_aligned(bdev, offset, size)) { |
1051 | sector_t start_sector = sector + (offset >> 9); | |
4b0228fa VV |
1052 | |
1053 | return blkdev_issue_zeroout(bdev, start_sector, | |
53ef7d0e | 1054 | size >> 9, GFP_NOFS, 0); |
4b0228fa | 1055 | } else { |
cccbce67 DW |
1056 | pgoff_t pgoff; |
1057 | long rc, id; | |
1058 | void *kaddr; | |
cccbce67 | 1059 | |
e84b83b9 | 1060 | rc = bdev_dax_pgoff(bdev, sector, PAGE_SIZE, &pgoff); |
cccbce67 DW |
1061 | if (rc) |
1062 | return rc; | |
1063 | ||
1064 | id = dax_read_lock(); | |
86ed913b | 1065 | rc = dax_direct_access(dax_dev, pgoff, 1, &kaddr, NULL); |
cccbce67 DW |
1066 | if (rc < 0) { |
1067 | dax_read_unlock(id); | |
1068 | return rc; | |
1069 | } | |
81f55870 | 1070 | memset(kaddr + offset, 0, size); |
c3ca015f | 1071 | dax_flush(dax_dev, kaddr + offset, size); |
cccbce67 | 1072 | dax_read_unlock(id); |
4b0228fa | 1073 | } |
679c8bd3 CH |
1074 | return 0; |
1075 | } | |
1076 | EXPORT_SYMBOL_GPL(__dax_zero_page_range); | |
1077 | ||
a254e568 | 1078 | static loff_t |
11c59c92 | 1079 | dax_iomap_actor(struct inode *inode, loff_t pos, loff_t length, void *data, |
a254e568 CH |
1080 | struct iomap *iomap) |
1081 | { | |
cccbce67 DW |
1082 | struct block_device *bdev = iomap->bdev; |
1083 | struct dax_device *dax_dev = iomap->dax_dev; | |
a254e568 CH |
1084 | struct iov_iter *iter = data; |
1085 | loff_t end = pos + length, done = 0; | |
1086 | ssize_t ret = 0; | |
a77d4786 | 1087 | size_t xfer; |
cccbce67 | 1088 | int id; |
a254e568 CH |
1089 | |
1090 | if (iov_iter_rw(iter) == READ) { | |
1091 | end = min(end, i_size_read(inode)); | |
1092 | if (pos >= end) | |
1093 | return 0; | |
1094 | ||
1095 | if (iomap->type == IOMAP_HOLE || iomap->type == IOMAP_UNWRITTEN) | |
1096 | return iov_iter_zero(min(length, end - pos), iter); | |
1097 | } | |
1098 | ||
1099 | if (WARN_ON_ONCE(iomap->type != IOMAP_MAPPED)) | |
1100 | return -EIO; | |
1101 | ||
e3fce68c JK |
1102 | /* |
1103 | * Write can allocate block for an area which has a hole page mapped | |
1104 | * into page tables. We have to tear down these mappings so that data | |
1105 | * written by write(2) is visible in mmap. | |
1106 | */ | |
cd656375 | 1107 | if (iomap->flags & IOMAP_F_NEW) { |
e3fce68c JK |
1108 | invalidate_inode_pages2_range(inode->i_mapping, |
1109 | pos >> PAGE_SHIFT, | |
1110 | (end - 1) >> PAGE_SHIFT); | |
1111 | } | |
1112 | ||
cccbce67 | 1113 | id = dax_read_lock(); |
a254e568 CH |
1114 | while (pos < end) { |
1115 | unsigned offset = pos & (PAGE_SIZE - 1); | |
cccbce67 DW |
1116 | const size_t size = ALIGN(length + offset, PAGE_SIZE); |
1117 | const sector_t sector = dax_iomap_sector(iomap, pos); | |
a254e568 | 1118 | ssize_t map_len; |
cccbce67 DW |
1119 | pgoff_t pgoff; |
1120 | void *kaddr; | |
a254e568 | 1121 | |
d1908f52 MH |
1122 | if (fatal_signal_pending(current)) { |
1123 | ret = -EINTR; | |
1124 | break; | |
1125 | } | |
1126 | ||
cccbce67 DW |
1127 | ret = bdev_dax_pgoff(bdev, sector, size, &pgoff); |
1128 | if (ret) | |
1129 | break; | |
1130 | ||
1131 | map_len = dax_direct_access(dax_dev, pgoff, PHYS_PFN(size), | |
86ed913b | 1132 | &kaddr, NULL); |
a254e568 CH |
1133 | if (map_len < 0) { |
1134 | ret = map_len; | |
1135 | break; | |
1136 | } | |
1137 | ||
cccbce67 DW |
1138 | map_len = PFN_PHYS(map_len); |
1139 | kaddr += offset; | |
a254e568 CH |
1140 | map_len -= offset; |
1141 | if (map_len > end - pos) | |
1142 | map_len = end - pos; | |
1143 | ||
a2e050f5 RZ |
1144 | /* |
1145 | * The userspace address for the memory copy has already been | |
1146 | * validated via access_ok() in either vfs_read() or | |
1147 | * vfs_write(), depending on which operation we are doing. | |
1148 | */ | |
a254e568 | 1149 | if (iov_iter_rw(iter) == WRITE) |
a77d4786 | 1150 | xfer = dax_copy_from_iter(dax_dev, pgoff, kaddr, |
fec53774 | 1151 | map_len, iter); |
a254e568 | 1152 | else |
a77d4786 | 1153 | xfer = dax_copy_to_iter(dax_dev, pgoff, kaddr, |
b3a9a0c3 | 1154 | map_len, iter); |
a254e568 | 1155 | |
a77d4786 DW |
1156 | pos += xfer; |
1157 | length -= xfer; | |
1158 | done += xfer; | |
1159 | ||
1160 | if (xfer == 0) | |
1161 | ret = -EFAULT; | |
1162 | if (xfer < map_len) | |
1163 | break; | |
a254e568 | 1164 | } |
cccbce67 | 1165 | dax_read_unlock(id); |
a254e568 CH |
1166 | |
1167 | return done ? done : ret; | |
1168 | } | |
1169 | ||
1170 | /** | |
11c59c92 | 1171 | * dax_iomap_rw - Perform I/O to a DAX file |
a254e568 CH |
1172 | * @iocb: The control block for this I/O |
1173 | * @iter: The addresses to do I/O from or to | |
1174 | * @ops: iomap ops passed from the file system | |
1175 | * | |
1176 | * This function performs read and write operations to directly mapped | |
1177 | * persistent memory. The callers needs to take care of read/write exclusion | |
1178 | * and evicting any page cache pages in the region under I/O. | |
1179 | */ | |
1180 | ssize_t | |
11c59c92 | 1181 | dax_iomap_rw(struct kiocb *iocb, struct iov_iter *iter, |
8ff6daa1 | 1182 | const struct iomap_ops *ops) |
a254e568 CH |
1183 | { |
1184 | struct address_space *mapping = iocb->ki_filp->f_mapping; | |
1185 | struct inode *inode = mapping->host; | |
1186 | loff_t pos = iocb->ki_pos, ret = 0, done = 0; | |
1187 | unsigned flags = 0; | |
1188 | ||
168316db | 1189 | if (iov_iter_rw(iter) == WRITE) { |
9ffbe8ac | 1190 | lockdep_assert_held_write(&inode->i_rwsem); |
a254e568 | 1191 | flags |= IOMAP_WRITE; |
168316db CH |
1192 | } else { |
1193 | lockdep_assert_held(&inode->i_rwsem); | |
1194 | } | |
a254e568 | 1195 | |
a254e568 CH |
1196 | while (iov_iter_count(iter)) { |
1197 | ret = iomap_apply(inode, pos, iov_iter_count(iter), flags, ops, | |
11c59c92 | 1198 | iter, dax_iomap_actor); |
a254e568 CH |
1199 | if (ret <= 0) |
1200 | break; | |
1201 | pos += ret; | |
1202 | done += ret; | |
1203 | } | |
1204 | ||
1205 | iocb->ki_pos += done; | |
1206 | return done ? done : ret; | |
1207 | } | |
11c59c92 | 1208 | EXPORT_SYMBOL_GPL(dax_iomap_rw); |
a7d73fe6 | 1209 | |
ab77dab4 | 1210 | static vm_fault_t dax_fault_return(int error) |
9f141d6e JK |
1211 | { |
1212 | if (error == 0) | |
1213 | return VM_FAULT_NOPAGE; | |
c9aed74e | 1214 | return vmf_error(error); |
9f141d6e JK |
1215 | } |
1216 | ||
aaa422c4 DW |
1217 | /* |
1218 | * MAP_SYNC on a dax mapping guarantees dirty metadata is | |
1219 | * flushed on write-faults (non-cow), but not read-faults. | |
1220 | */ | |
1221 | static bool dax_fault_is_synchronous(unsigned long flags, | |
1222 | struct vm_area_struct *vma, struct iomap *iomap) | |
1223 | { | |
1224 | return (flags & IOMAP_WRITE) && (vma->vm_flags & VM_SYNC) | |
1225 | && (iomap->flags & IOMAP_F_DIRTY); | |
1226 | } | |
1227 | ||
ab77dab4 | 1228 | static vm_fault_t dax_iomap_pte_fault(struct vm_fault *vmf, pfn_t *pfnp, |
c0b24625 | 1229 | int *iomap_errp, const struct iomap_ops *ops) |
a7d73fe6 | 1230 | { |
a0987ad5 JK |
1231 | struct vm_area_struct *vma = vmf->vma; |
1232 | struct address_space *mapping = vma->vm_file->f_mapping; | |
b15cd800 | 1233 | XA_STATE(xas, &mapping->i_pages, vmf->pgoff); |
a7d73fe6 | 1234 | struct inode *inode = mapping->host; |
1a29d85e | 1235 | unsigned long vaddr = vmf->address; |
a7d73fe6 | 1236 | loff_t pos = (loff_t)vmf->pgoff << PAGE_SHIFT; |
a7d73fe6 | 1237 | struct iomap iomap = { 0 }; |
9484ab1b | 1238 | unsigned flags = IOMAP_FAULT; |
a7d73fe6 | 1239 | int error, major = 0; |
d2c43ef1 | 1240 | bool write = vmf->flags & FAULT_FLAG_WRITE; |
caa51d26 | 1241 | bool sync; |
ab77dab4 | 1242 | vm_fault_t ret = 0; |
a7d73fe6 | 1243 | void *entry; |
1b5a1cb2 | 1244 | pfn_t pfn; |
a7d73fe6 | 1245 | |
ab77dab4 | 1246 | trace_dax_pte_fault(inode, vmf, ret); |
a7d73fe6 CH |
1247 | /* |
1248 | * Check whether offset isn't beyond end of file now. Caller is supposed | |
1249 | * to hold locks serializing us with truncate / punch hole so this is | |
1250 | * a reliable test. | |
1251 | */ | |
a9c42b33 | 1252 | if (pos >= i_size_read(inode)) { |
ab77dab4 | 1253 | ret = VM_FAULT_SIGBUS; |
a9c42b33 RZ |
1254 | goto out; |
1255 | } | |
a7d73fe6 | 1256 | |
d2c43ef1 | 1257 | if (write && !vmf->cow_page) |
a7d73fe6 CH |
1258 | flags |= IOMAP_WRITE; |
1259 | ||
b15cd800 MW |
1260 | entry = grab_mapping_entry(&xas, mapping, 0); |
1261 | if (xa_is_internal(entry)) { | |
1262 | ret = xa_to_internal(entry); | |
13e451fd JK |
1263 | goto out; |
1264 | } | |
1265 | ||
e2093926 RZ |
1266 | /* |
1267 | * It is possible, particularly with mixed reads & writes to private | |
1268 | * mappings, that we have raced with a PMD fault that overlaps with | |
1269 | * the PTE we need to set up. If so just return and the fault will be | |
1270 | * retried. | |
1271 | */ | |
1272 | if (pmd_trans_huge(*vmf->pmd) || pmd_devmap(*vmf->pmd)) { | |
ab77dab4 | 1273 | ret = VM_FAULT_NOPAGE; |
e2093926 RZ |
1274 | goto unlock_entry; |
1275 | } | |
1276 | ||
a7d73fe6 CH |
1277 | /* |
1278 | * Note that we don't bother to use iomap_apply here: DAX required | |
1279 | * the file system block size to be equal the page size, which means | |
1280 | * that we never have to deal with more than a single extent here. | |
1281 | */ | |
1282 | error = ops->iomap_begin(inode, pos, PAGE_SIZE, flags, &iomap); | |
c0b24625 JK |
1283 | if (iomap_errp) |
1284 | *iomap_errp = error; | |
a9c42b33 | 1285 | if (error) { |
ab77dab4 | 1286 | ret = dax_fault_return(error); |
13e451fd | 1287 | goto unlock_entry; |
a9c42b33 | 1288 | } |
a7d73fe6 | 1289 | if (WARN_ON_ONCE(iomap.offset + iomap.length < pos + PAGE_SIZE)) { |
13e451fd JK |
1290 | error = -EIO; /* fs corruption? */ |
1291 | goto error_finish_iomap; | |
a7d73fe6 CH |
1292 | } |
1293 | ||
a7d73fe6 | 1294 | if (vmf->cow_page) { |
31a6f1a6 JK |
1295 | sector_t sector = dax_iomap_sector(&iomap, pos); |
1296 | ||
a7d73fe6 CH |
1297 | switch (iomap.type) { |
1298 | case IOMAP_HOLE: | |
1299 | case IOMAP_UNWRITTEN: | |
1300 | clear_user_highpage(vmf->cow_page, vaddr); | |
1301 | break; | |
1302 | case IOMAP_MAPPED: | |
cccbce67 DW |
1303 | error = copy_user_dax(iomap.bdev, iomap.dax_dev, |
1304 | sector, PAGE_SIZE, vmf->cow_page, vaddr); | |
a7d73fe6 CH |
1305 | break; |
1306 | default: | |
1307 | WARN_ON_ONCE(1); | |
1308 | error = -EIO; | |
1309 | break; | |
1310 | } | |
1311 | ||
1312 | if (error) | |
13e451fd | 1313 | goto error_finish_iomap; |
b1aa812b JK |
1314 | |
1315 | __SetPageUptodate(vmf->cow_page); | |
ab77dab4 SJ |
1316 | ret = finish_fault(vmf); |
1317 | if (!ret) | |
1318 | ret = VM_FAULT_DONE_COW; | |
13e451fd | 1319 | goto finish_iomap; |
a7d73fe6 CH |
1320 | } |
1321 | ||
aaa422c4 | 1322 | sync = dax_fault_is_synchronous(flags, vma, &iomap); |
caa51d26 | 1323 | |
a7d73fe6 CH |
1324 | switch (iomap.type) { |
1325 | case IOMAP_MAPPED: | |
1326 | if (iomap.flags & IOMAP_F_NEW) { | |
1327 | count_vm_event(PGMAJFAULT); | |
a0987ad5 | 1328 | count_memcg_event_mm(vma->vm_mm, PGMAJFAULT); |
a7d73fe6 CH |
1329 | major = VM_FAULT_MAJOR; |
1330 | } | |
1b5a1cb2 JK |
1331 | error = dax_iomap_pfn(&iomap, pos, PAGE_SIZE, &pfn); |
1332 | if (error < 0) | |
1333 | goto error_finish_iomap; | |
1334 | ||
b15cd800 | 1335 | entry = dax_insert_entry(&xas, mapping, vmf, entry, pfn, |
caa51d26 | 1336 | 0, write && !sync); |
1b5a1cb2 | 1337 | |
caa51d26 JK |
1338 | /* |
1339 | * If we are doing synchronous page fault and inode needs fsync, | |
1340 | * we can insert PTE into page tables only after that happens. | |
1341 | * Skip insertion for now and return the pfn so that caller can | |
1342 | * insert it after fsync is done. | |
1343 | */ | |
1344 | if (sync) { | |
1345 | if (WARN_ON_ONCE(!pfnp)) { | |
1346 | error = -EIO; | |
1347 | goto error_finish_iomap; | |
1348 | } | |
1349 | *pfnp = pfn; | |
ab77dab4 | 1350 | ret = VM_FAULT_NEEDDSYNC | major; |
caa51d26 JK |
1351 | goto finish_iomap; |
1352 | } | |
1b5a1cb2 JK |
1353 | trace_dax_insert_mapping(inode, vmf, entry); |
1354 | if (write) | |
ab77dab4 | 1355 | ret = vmf_insert_mixed_mkwrite(vma, vaddr, pfn); |
1b5a1cb2 | 1356 | else |
ab77dab4 | 1357 | ret = vmf_insert_mixed(vma, vaddr, pfn); |
1b5a1cb2 | 1358 | |
ab77dab4 | 1359 | goto finish_iomap; |
a7d73fe6 CH |
1360 | case IOMAP_UNWRITTEN: |
1361 | case IOMAP_HOLE: | |
d2c43ef1 | 1362 | if (!write) { |
b15cd800 | 1363 | ret = dax_load_hole(&xas, mapping, &entry, vmf); |
13e451fd | 1364 | goto finish_iomap; |
1550290b | 1365 | } |
a7d73fe6 CH |
1366 | /*FALLTHRU*/ |
1367 | default: | |
1368 | WARN_ON_ONCE(1); | |
1369 | error = -EIO; | |
1370 | break; | |
1371 | } | |
1372 | ||
13e451fd | 1373 | error_finish_iomap: |
ab77dab4 | 1374 | ret = dax_fault_return(error); |
9f141d6e JK |
1375 | finish_iomap: |
1376 | if (ops->iomap_end) { | |
1377 | int copied = PAGE_SIZE; | |
1378 | ||
ab77dab4 | 1379 | if (ret & VM_FAULT_ERROR) |
9f141d6e JK |
1380 | copied = 0; |
1381 | /* | |
1382 | * The fault is done by now and there's no way back (other | |
1383 | * thread may be already happily using PTE we have installed). | |
1384 | * Just ignore error from ->iomap_end since we cannot do much | |
1385 | * with it. | |
1386 | */ | |
1387 | ops->iomap_end(inode, pos, PAGE_SIZE, copied, flags, &iomap); | |
1550290b | 1388 | } |
13e451fd | 1389 | unlock_entry: |
b15cd800 | 1390 | dax_unlock_entry(&xas, entry); |
13e451fd | 1391 | out: |
ab77dab4 SJ |
1392 | trace_dax_pte_fault_done(inode, vmf, ret); |
1393 | return ret | major; | |
a7d73fe6 | 1394 | } |
642261ac RZ |
1395 | |
1396 | #ifdef CONFIG_FS_DAX_PMD | |
b15cd800 MW |
1397 | static vm_fault_t dax_pmd_load_hole(struct xa_state *xas, struct vm_fault *vmf, |
1398 | struct iomap *iomap, void **entry) | |
642261ac | 1399 | { |
f4200391 DJ |
1400 | struct address_space *mapping = vmf->vma->vm_file->f_mapping; |
1401 | unsigned long pmd_addr = vmf->address & PMD_MASK; | |
11cf9d86 | 1402 | struct vm_area_struct *vma = vmf->vma; |
653b2ea3 | 1403 | struct inode *inode = mapping->host; |
11cf9d86 | 1404 | pgtable_t pgtable = NULL; |
642261ac RZ |
1405 | struct page *zero_page; |
1406 | spinlock_t *ptl; | |
1407 | pmd_t pmd_entry; | |
3fe0791c | 1408 | pfn_t pfn; |
642261ac | 1409 | |
f4200391 | 1410 | zero_page = mm_get_huge_zero_page(vmf->vma->vm_mm); |
642261ac RZ |
1411 | |
1412 | if (unlikely(!zero_page)) | |
653b2ea3 | 1413 | goto fallback; |
642261ac | 1414 | |
3fe0791c | 1415 | pfn = page_to_pfn_t(zero_page); |
b15cd800 | 1416 | *entry = dax_insert_entry(xas, mapping, vmf, *entry, pfn, |
3159f943 | 1417 | DAX_PMD | DAX_ZERO_PAGE, false); |
642261ac | 1418 | |
11cf9d86 AK |
1419 | if (arch_needs_pgtable_deposit()) { |
1420 | pgtable = pte_alloc_one(vma->vm_mm); | |
1421 | if (!pgtable) | |
1422 | return VM_FAULT_OOM; | |
1423 | } | |
1424 | ||
f4200391 DJ |
1425 | ptl = pmd_lock(vmf->vma->vm_mm, vmf->pmd); |
1426 | if (!pmd_none(*(vmf->pmd))) { | |
642261ac | 1427 | spin_unlock(ptl); |
653b2ea3 | 1428 | goto fallback; |
642261ac RZ |
1429 | } |
1430 | ||
11cf9d86 AK |
1431 | if (pgtable) { |
1432 | pgtable_trans_huge_deposit(vma->vm_mm, vmf->pmd, pgtable); | |
1433 | mm_inc_nr_ptes(vma->vm_mm); | |
1434 | } | |
f4200391 | 1435 | pmd_entry = mk_pmd(zero_page, vmf->vma->vm_page_prot); |
642261ac | 1436 | pmd_entry = pmd_mkhuge(pmd_entry); |
f4200391 | 1437 | set_pmd_at(vmf->vma->vm_mm, pmd_addr, vmf->pmd, pmd_entry); |
642261ac | 1438 | spin_unlock(ptl); |
b15cd800 | 1439 | trace_dax_pmd_load_hole(inode, vmf, zero_page, *entry); |
642261ac | 1440 | return VM_FAULT_NOPAGE; |
653b2ea3 RZ |
1441 | |
1442 | fallback: | |
11cf9d86 AK |
1443 | if (pgtable) |
1444 | pte_free(vma->vm_mm, pgtable); | |
b15cd800 | 1445 | trace_dax_pmd_load_hole_fallback(inode, vmf, zero_page, *entry); |
653b2ea3 | 1446 | return VM_FAULT_FALLBACK; |
642261ac RZ |
1447 | } |
1448 | ||
ab77dab4 | 1449 | static vm_fault_t dax_iomap_pmd_fault(struct vm_fault *vmf, pfn_t *pfnp, |
a2d58167 | 1450 | const struct iomap_ops *ops) |
642261ac | 1451 | { |
f4200391 | 1452 | struct vm_area_struct *vma = vmf->vma; |
642261ac | 1453 | struct address_space *mapping = vma->vm_file->f_mapping; |
b15cd800 | 1454 | XA_STATE_ORDER(xas, &mapping->i_pages, vmf->pgoff, PMD_ORDER); |
d8a849e1 DJ |
1455 | unsigned long pmd_addr = vmf->address & PMD_MASK; |
1456 | bool write = vmf->flags & FAULT_FLAG_WRITE; | |
caa51d26 | 1457 | bool sync; |
9484ab1b | 1458 | unsigned int iomap_flags = (write ? IOMAP_WRITE : 0) | IOMAP_FAULT; |
642261ac | 1459 | struct inode *inode = mapping->host; |
ab77dab4 | 1460 | vm_fault_t result = VM_FAULT_FALLBACK; |
642261ac | 1461 | struct iomap iomap = { 0 }; |
b15cd800 | 1462 | pgoff_t max_pgoff; |
642261ac RZ |
1463 | void *entry; |
1464 | loff_t pos; | |
1465 | int error; | |
302a5e31 | 1466 | pfn_t pfn; |
642261ac | 1467 | |
282a8e03 RZ |
1468 | /* |
1469 | * Check whether offset isn't beyond end of file now. Caller is | |
1470 | * supposed to hold locks serializing us with truncate / punch hole so | |
1471 | * this is a reliable test. | |
1472 | */ | |
957ac8c4 | 1473 | max_pgoff = DIV_ROUND_UP(i_size_read(inode), PAGE_SIZE); |
282a8e03 | 1474 | |
f4200391 | 1475 | trace_dax_pmd_fault(inode, vmf, max_pgoff, 0); |
282a8e03 | 1476 | |
fffa281b RZ |
1477 | /* |
1478 | * Make sure that the faulting address's PMD offset (color) matches | |
1479 | * the PMD offset from the start of the file. This is necessary so | |
1480 | * that a PMD range in the page table overlaps exactly with a PMD | |
a77d19f4 | 1481 | * range in the page cache. |
fffa281b RZ |
1482 | */ |
1483 | if ((vmf->pgoff & PG_PMD_COLOUR) != | |
1484 | ((vmf->address >> PAGE_SHIFT) & PG_PMD_COLOUR)) | |
1485 | goto fallback; | |
1486 | ||
642261ac RZ |
1487 | /* Fall back to PTEs if we're going to COW */ |
1488 | if (write && !(vma->vm_flags & VM_SHARED)) | |
1489 | goto fallback; | |
1490 | ||
1491 | /* If the PMD would extend outside the VMA */ | |
1492 | if (pmd_addr < vma->vm_start) | |
1493 | goto fallback; | |
1494 | if ((pmd_addr + PMD_SIZE) > vma->vm_end) | |
1495 | goto fallback; | |
1496 | ||
b15cd800 | 1497 | if (xas.xa_index >= max_pgoff) { |
282a8e03 RZ |
1498 | result = VM_FAULT_SIGBUS; |
1499 | goto out; | |
1500 | } | |
642261ac RZ |
1501 | |
1502 | /* If the PMD would extend beyond the file size */ | |
b15cd800 | 1503 | if ((xas.xa_index | PG_PMD_COLOUR) >= max_pgoff) |
642261ac RZ |
1504 | goto fallback; |
1505 | ||
876f2946 | 1506 | /* |
b15cd800 MW |
1507 | * grab_mapping_entry() will make sure we get an empty PMD entry, |
1508 | * a zero PMD entry or a DAX PMD. If it can't (because a PTE | |
1509 | * entry is already in the array, for instance), it will return | |
1510 | * VM_FAULT_FALLBACK. | |
876f2946 | 1511 | */ |
b15cd800 MW |
1512 | entry = grab_mapping_entry(&xas, mapping, DAX_PMD); |
1513 | if (xa_is_internal(entry)) { | |
1514 | result = xa_to_internal(entry); | |
876f2946 | 1515 | goto fallback; |
b15cd800 | 1516 | } |
876f2946 | 1517 | |
e2093926 RZ |
1518 | /* |
1519 | * It is possible, particularly with mixed reads & writes to private | |
1520 | * mappings, that we have raced with a PTE fault that overlaps with | |
1521 | * the PMD we need to set up. If so just return and the fault will be | |
1522 | * retried. | |
1523 | */ | |
1524 | if (!pmd_none(*vmf->pmd) && !pmd_trans_huge(*vmf->pmd) && | |
1525 | !pmd_devmap(*vmf->pmd)) { | |
1526 | result = 0; | |
1527 | goto unlock_entry; | |
1528 | } | |
1529 | ||
642261ac RZ |
1530 | /* |
1531 | * Note that we don't use iomap_apply here. We aren't doing I/O, only | |
1532 | * setting up a mapping, so really we're using iomap_begin() as a way | |
1533 | * to look up our filesystem block. | |
1534 | */ | |
b15cd800 | 1535 | pos = (loff_t)xas.xa_index << PAGE_SHIFT; |
642261ac RZ |
1536 | error = ops->iomap_begin(inode, pos, PMD_SIZE, iomap_flags, &iomap); |
1537 | if (error) | |
876f2946 | 1538 | goto unlock_entry; |
9f141d6e | 1539 | |
642261ac RZ |
1540 | if (iomap.offset + iomap.length < pos + PMD_SIZE) |
1541 | goto finish_iomap; | |
1542 | ||
aaa422c4 | 1543 | sync = dax_fault_is_synchronous(iomap_flags, vma, &iomap); |
caa51d26 | 1544 | |
642261ac RZ |
1545 | switch (iomap.type) { |
1546 | case IOMAP_MAPPED: | |
302a5e31 JK |
1547 | error = dax_iomap_pfn(&iomap, pos, PMD_SIZE, &pfn); |
1548 | if (error < 0) | |
1549 | goto finish_iomap; | |
1550 | ||
b15cd800 | 1551 | entry = dax_insert_entry(&xas, mapping, vmf, entry, pfn, |
3159f943 | 1552 | DAX_PMD, write && !sync); |
302a5e31 | 1553 | |
caa51d26 JK |
1554 | /* |
1555 | * If we are doing synchronous page fault and inode needs fsync, | |
1556 | * we can insert PMD into page tables only after that happens. | |
1557 | * Skip insertion for now and return the pfn so that caller can | |
1558 | * insert it after fsync is done. | |
1559 | */ | |
1560 | if (sync) { | |
1561 | if (WARN_ON_ONCE(!pfnp)) | |
1562 | goto finish_iomap; | |
1563 | *pfnp = pfn; | |
1564 | result = VM_FAULT_NEEDDSYNC; | |
1565 | goto finish_iomap; | |
1566 | } | |
1567 | ||
302a5e31 | 1568 | trace_dax_pmd_insert_mapping(inode, vmf, PMD_SIZE, pfn, entry); |
fce86ff5 | 1569 | result = vmf_insert_pfn_pmd(vmf, pfn, write); |
642261ac RZ |
1570 | break; |
1571 | case IOMAP_UNWRITTEN: | |
1572 | case IOMAP_HOLE: | |
1573 | if (WARN_ON_ONCE(write)) | |
876f2946 | 1574 | break; |
b15cd800 | 1575 | result = dax_pmd_load_hole(&xas, vmf, &iomap, &entry); |
642261ac RZ |
1576 | break; |
1577 | default: | |
1578 | WARN_ON_ONCE(1); | |
1579 | break; | |
1580 | } | |
1581 | ||
1582 | finish_iomap: | |
1583 | if (ops->iomap_end) { | |
9f141d6e JK |
1584 | int copied = PMD_SIZE; |
1585 | ||
1586 | if (result == VM_FAULT_FALLBACK) | |
1587 | copied = 0; | |
1588 | /* | |
1589 | * The fault is done by now and there's no way back (other | |
1590 | * thread may be already happily using PMD we have installed). | |
1591 | * Just ignore error from ->iomap_end since we cannot do much | |
1592 | * with it. | |
1593 | */ | |
1594 | ops->iomap_end(inode, pos, PMD_SIZE, copied, iomap_flags, | |
1595 | &iomap); | |
642261ac | 1596 | } |
876f2946 | 1597 | unlock_entry: |
b15cd800 | 1598 | dax_unlock_entry(&xas, entry); |
642261ac RZ |
1599 | fallback: |
1600 | if (result == VM_FAULT_FALLBACK) { | |
d8a849e1 | 1601 | split_huge_pmd(vma, vmf->pmd, vmf->address); |
642261ac RZ |
1602 | count_vm_event(THP_FAULT_FALLBACK); |
1603 | } | |
282a8e03 | 1604 | out: |
f4200391 | 1605 | trace_dax_pmd_fault_done(inode, vmf, max_pgoff, result); |
642261ac RZ |
1606 | return result; |
1607 | } | |
a2d58167 | 1608 | #else |
ab77dab4 | 1609 | static vm_fault_t dax_iomap_pmd_fault(struct vm_fault *vmf, pfn_t *pfnp, |
01cddfe9 | 1610 | const struct iomap_ops *ops) |
a2d58167 DJ |
1611 | { |
1612 | return VM_FAULT_FALLBACK; | |
1613 | } | |
642261ac | 1614 | #endif /* CONFIG_FS_DAX_PMD */ |
a2d58167 DJ |
1615 | |
1616 | /** | |
1617 | * dax_iomap_fault - handle a page fault on a DAX file | |
1618 | * @vmf: The description of the fault | |
cec04e8c | 1619 | * @pe_size: Size of the page to fault in |
9a0dd422 | 1620 | * @pfnp: PFN to insert for synchronous faults if fsync is required |
c0b24625 | 1621 | * @iomap_errp: Storage for detailed error code in case of error |
cec04e8c | 1622 | * @ops: Iomap ops passed from the file system |
a2d58167 DJ |
1623 | * |
1624 | * When a page fault occurs, filesystems may call this helper in | |
1625 | * their fault handler for DAX files. dax_iomap_fault() assumes the caller | |
1626 | * has done all the necessary locking for page fault to proceed | |
1627 | * successfully. | |
1628 | */ | |
ab77dab4 | 1629 | vm_fault_t dax_iomap_fault(struct vm_fault *vmf, enum page_entry_size pe_size, |
c0b24625 | 1630 | pfn_t *pfnp, int *iomap_errp, const struct iomap_ops *ops) |
a2d58167 | 1631 | { |
c791ace1 DJ |
1632 | switch (pe_size) { |
1633 | case PE_SIZE_PTE: | |
c0b24625 | 1634 | return dax_iomap_pte_fault(vmf, pfnp, iomap_errp, ops); |
c791ace1 | 1635 | case PE_SIZE_PMD: |
9a0dd422 | 1636 | return dax_iomap_pmd_fault(vmf, pfnp, ops); |
a2d58167 DJ |
1637 | default: |
1638 | return VM_FAULT_FALLBACK; | |
1639 | } | |
1640 | } | |
1641 | EXPORT_SYMBOL_GPL(dax_iomap_fault); | |
71eab6df | 1642 | |
a77d19f4 | 1643 | /* |
71eab6df JK |
1644 | * dax_insert_pfn_mkwrite - insert PTE or PMD entry into page tables |
1645 | * @vmf: The description of the fault | |
71eab6df | 1646 | * @pfn: PFN to insert |
cfc93c6c | 1647 | * @order: Order of entry to insert. |
71eab6df | 1648 | * |
a77d19f4 MW |
1649 | * This function inserts a writeable PTE or PMD entry into the page tables |
1650 | * for an mmaped DAX file. It also marks the page cache entry as dirty. | |
71eab6df | 1651 | */ |
cfc93c6c MW |
1652 | static vm_fault_t |
1653 | dax_insert_pfn_mkwrite(struct vm_fault *vmf, pfn_t pfn, unsigned int order) | |
71eab6df JK |
1654 | { |
1655 | struct address_space *mapping = vmf->vma->vm_file->f_mapping; | |
cfc93c6c MW |
1656 | XA_STATE_ORDER(xas, &mapping->i_pages, vmf->pgoff, order); |
1657 | void *entry; | |
ab77dab4 | 1658 | vm_fault_t ret; |
71eab6df | 1659 | |
cfc93c6c MW |
1660 | xas_lock_irq(&xas); |
1661 | entry = get_unlocked_entry(&xas); | |
71eab6df JK |
1662 | /* Did we race with someone splitting entry or so? */ |
1663 | if (!entry || | |
cfc93c6c | 1664 | (order == 0 && !dax_is_pte_entry(entry)) || |
0e40de03 | 1665 | (order == PMD_ORDER && !dax_is_pmd_entry(entry))) { |
cfc93c6c MW |
1666 | put_unlocked_entry(&xas, entry); |
1667 | xas_unlock_irq(&xas); | |
71eab6df JK |
1668 | trace_dax_insert_pfn_mkwrite_no_entry(mapping->host, vmf, |
1669 | VM_FAULT_NOPAGE); | |
1670 | return VM_FAULT_NOPAGE; | |
1671 | } | |
cfc93c6c MW |
1672 | xas_set_mark(&xas, PAGECACHE_TAG_DIRTY); |
1673 | dax_lock_entry(&xas, entry); | |
1674 | xas_unlock_irq(&xas); | |
1675 | if (order == 0) | |
ab77dab4 | 1676 | ret = vmf_insert_mixed_mkwrite(vmf->vma, vmf->address, pfn); |
71eab6df | 1677 | #ifdef CONFIG_FS_DAX_PMD |
cfc93c6c | 1678 | else if (order == PMD_ORDER) |
fce86ff5 | 1679 | ret = vmf_insert_pfn_pmd(vmf, pfn, FAULT_FLAG_WRITE); |
71eab6df | 1680 | #endif |
cfc93c6c | 1681 | else |
ab77dab4 | 1682 | ret = VM_FAULT_FALLBACK; |
cfc93c6c | 1683 | dax_unlock_entry(&xas, entry); |
ab77dab4 SJ |
1684 | trace_dax_insert_pfn_mkwrite(mapping->host, vmf, ret); |
1685 | return ret; | |
71eab6df JK |
1686 | } |
1687 | ||
1688 | /** | |
1689 | * dax_finish_sync_fault - finish synchronous page fault | |
1690 | * @vmf: The description of the fault | |
1691 | * @pe_size: Size of entry to be inserted | |
1692 | * @pfn: PFN to insert | |
1693 | * | |
1694 | * This function ensures that the file range touched by the page fault is | |
1695 | * stored persistently on the media and handles inserting of appropriate page | |
1696 | * table entry. | |
1697 | */ | |
ab77dab4 SJ |
1698 | vm_fault_t dax_finish_sync_fault(struct vm_fault *vmf, |
1699 | enum page_entry_size pe_size, pfn_t pfn) | |
71eab6df JK |
1700 | { |
1701 | int err; | |
1702 | loff_t start = ((loff_t)vmf->pgoff) << PAGE_SHIFT; | |
cfc93c6c MW |
1703 | unsigned int order = pe_order(pe_size); |
1704 | size_t len = PAGE_SIZE << order; | |
71eab6df | 1705 | |
71eab6df JK |
1706 | err = vfs_fsync_range(vmf->vma->vm_file, start, start + len - 1, 1); |
1707 | if (err) | |
1708 | return VM_FAULT_SIGBUS; | |
cfc93c6c | 1709 | return dax_insert_pfn_mkwrite(vmf, pfn, order); |
71eab6df JK |
1710 | } |
1711 | EXPORT_SYMBOL_GPL(dax_finish_sync_fault); |