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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 <matthew.r.wilcox@intel.com> | |
6 | * Author: Ross Zwisler <ross.zwisler@linux.intel.com> | |
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 | 13 | #include <linux/fs.h> |
f7ca90b1 MW |
14 | #include <linux/highmem.h> |
15 | #include <linux/memcontrol.h> | |
16 | #include <linux/mm.h> | |
d475c634 | 17 | #include <linux/mutex.h> |
9973c98e | 18 | #include <linux/pagevec.h> |
289c6aed | 19 | #include <linux/sched.h> |
f361bf4a | 20 | #include <linux/sched/signal.h> |
d475c634 | 21 | #include <linux/uio.h> |
f7ca90b1 | 22 | #include <linux/vmstat.h> |
34c0fd54 | 23 | #include <linux/pfn_t.h> |
0e749e54 | 24 | #include <linux/sizes.h> |
4b4bb46d | 25 | #include <linux/mmu_notifier.h> |
a254e568 | 26 | #include <linux/iomap.h> |
06083a09 | 27 | #include <linux/rmap.h> |
11cf9d86 | 28 | #include <asm/pgalloc.h> |
d475c634 | 29 | |
282a8e03 RZ |
30 | #define CREATE_TRACE_POINTS |
31 | #include <trace/events/fs_dax.h> | |
32 | ||
ac401cc7 JK |
33 | /* We choose 4096 entries - same as per-zone page wait tables */ |
34 | #define DAX_WAIT_TABLE_BITS 12 | |
35 | #define DAX_WAIT_TABLE_ENTRIES (1 << DAX_WAIT_TABLE_BITS) | |
36 | ||
917f3452 RZ |
37 | /* The 'colour' (ie low bits) within a PMD of a page offset. */ |
38 | #define PG_PMD_COLOUR ((PMD_SIZE >> PAGE_SHIFT) - 1) | |
977fbdcd | 39 | #define PG_PMD_NR (PMD_SIZE >> PAGE_SHIFT) |
917f3452 | 40 | |
ce95ab0f | 41 | static wait_queue_head_t wait_table[DAX_WAIT_TABLE_ENTRIES]; |
ac401cc7 JK |
42 | |
43 | static int __init init_dax_wait_table(void) | |
44 | { | |
45 | int i; | |
46 | ||
47 | for (i = 0; i < DAX_WAIT_TABLE_ENTRIES; i++) | |
48 | init_waitqueue_head(wait_table + i); | |
49 | return 0; | |
50 | } | |
51 | fs_initcall(init_dax_wait_table); | |
52 | ||
527b19d0 | 53 | /* |
3159f943 MW |
54 | * DAX pagecache entries use XArray value entries so they can't be mistaken |
55 | * for pages. We use one bit for locking, one bit for the entry size (PMD) | |
56 | * and two more to tell us if the entry is a zero page or an empty entry that | |
57 | * is just used for locking. In total four special bits. | |
527b19d0 RZ |
58 | * |
59 | * If the PMD bit isn't set the entry has size PAGE_SIZE, and if the ZERO_PAGE | |
60 | * and EMPTY bits aren't set the entry is a normal DAX entry with a filesystem | |
61 | * block allocation. | |
62 | */ | |
3159f943 MW |
63 | #define DAX_SHIFT (4) |
64 | #define DAX_LOCKED (1UL << 0) | |
65 | #define DAX_PMD (1UL << 1) | |
66 | #define DAX_ZERO_PAGE (1UL << 2) | |
67 | #define DAX_EMPTY (1UL << 3) | |
527b19d0 | 68 | |
a77d19f4 | 69 | static unsigned long dax_to_pfn(void *entry) |
527b19d0 | 70 | { |
3159f943 | 71 | return xa_to_value(entry) >> DAX_SHIFT; |
527b19d0 RZ |
72 | } |
73 | ||
9f32d221 MW |
74 | static void *dax_make_entry(pfn_t pfn, unsigned long flags) |
75 | { | |
76 | return xa_mk_value(flags | (pfn_t_to_pfn(pfn) << DAX_SHIFT)); | |
77 | } | |
78 | ||
cfc93c6c MW |
79 | static bool dax_is_locked(void *entry) |
80 | { | |
81 | return xa_to_value(entry) & DAX_LOCKED; | |
82 | } | |
83 | ||
a77d19f4 | 84 | static unsigned int dax_entry_order(void *entry) |
527b19d0 | 85 | { |
3159f943 | 86 | if (xa_to_value(entry) & DAX_PMD) |
cfc93c6c | 87 | return PMD_ORDER; |
527b19d0 RZ |
88 | return 0; |
89 | } | |
90 | ||
fda490d3 | 91 | static unsigned long dax_is_pmd_entry(void *entry) |
d1a5f2b4 | 92 | { |
3159f943 | 93 | return xa_to_value(entry) & DAX_PMD; |
d1a5f2b4 DW |
94 | } |
95 | ||
fda490d3 | 96 | static bool dax_is_pte_entry(void *entry) |
d475c634 | 97 | { |
3159f943 | 98 | return !(xa_to_value(entry) & DAX_PMD); |
d475c634 MW |
99 | } |
100 | ||
642261ac | 101 | static int dax_is_zero_entry(void *entry) |
d475c634 | 102 | { |
3159f943 | 103 | return xa_to_value(entry) & DAX_ZERO_PAGE; |
d475c634 MW |
104 | } |
105 | ||
642261ac | 106 | static int dax_is_empty_entry(void *entry) |
b2e0d162 | 107 | { |
3159f943 | 108 | return xa_to_value(entry) & DAX_EMPTY; |
b2e0d162 DW |
109 | } |
110 | ||
23c84eb7 MWO |
111 | /* |
112 | * true if the entry that was found is of a smaller order than the entry | |
113 | * we were looking for | |
114 | */ | |
115 | static bool dax_is_conflict(void *entry) | |
116 | { | |
117 | return entry == XA_RETRY_ENTRY; | |
118 | } | |
119 | ||
ac401cc7 | 120 | /* |
a77d19f4 | 121 | * DAX page cache entry locking |
ac401cc7 JK |
122 | */ |
123 | struct exceptional_entry_key { | |
ec4907ff | 124 | struct xarray *xa; |
63e95b5c | 125 | pgoff_t entry_start; |
ac401cc7 JK |
126 | }; |
127 | ||
128 | struct wait_exceptional_entry_queue { | |
ac6424b9 | 129 | wait_queue_entry_t wait; |
ac401cc7 JK |
130 | struct exceptional_entry_key key; |
131 | }; | |
132 | ||
698ab77a VG |
133 | /** |
134 | * enum dax_wake_mode: waitqueue wakeup behaviour | |
135 | * @WAKE_ALL: wake all waiters in the waitqueue | |
136 | * @WAKE_NEXT: wake only the first waiter in the waitqueue | |
137 | */ | |
138 | enum dax_wake_mode { | |
139 | WAKE_ALL, | |
140 | WAKE_NEXT, | |
141 | }; | |
142 | ||
b15cd800 MW |
143 | static wait_queue_head_t *dax_entry_waitqueue(struct xa_state *xas, |
144 | void *entry, struct exceptional_entry_key *key) | |
63e95b5c RZ |
145 | { |
146 | unsigned long hash; | |
b15cd800 | 147 | unsigned long index = xas->xa_index; |
63e95b5c RZ |
148 | |
149 | /* | |
150 | * If 'entry' is a PMD, align the 'index' that we use for the wait | |
151 | * queue to the start of that PMD. This ensures that all offsets in | |
152 | * the range covered by the PMD map to the same bit lock. | |
153 | */ | |
642261ac | 154 | if (dax_is_pmd_entry(entry)) |
917f3452 | 155 | index &= ~PG_PMD_COLOUR; |
b15cd800 | 156 | key->xa = xas->xa; |
63e95b5c RZ |
157 | key->entry_start = index; |
158 | ||
b15cd800 | 159 | hash = hash_long((unsigned long)xas->xa ^ index, DAX_WAIT_TABLE_BITS); |
63e95b5c RZ |
160 | return wait_table + hash; |
161 | } | |
162 | ||
ec4907ff MW |
163 | static int wake_exceptional_entry_func(wait_queue_entry_t *wait, |
164 | unsigned int mode, int sync, void *keyp) | |
ac401cc7 JK |
165 | { |
166 | struct exceptional_entry_key *key = keyp; | |
167 | struct wait_exceptional_entry_queue *ewait = | |
168 | container_of(wait, struct wait_exceptional_entry_queue, wait); | |
169 | ||
ec4907ff | 170 | if (key->xa != ewait->key.xa || |
63e95b5c | 171 | key->entry_start != ewait->key.entry_start) |
ac401cc7 JK |
172 | return 0; |
173 | return autoremove_wake_function(wait, mode, sync, NULL); | |
174 | } | |
175 | ||
e30331ff | 176 | /* |
b93b0163 MW |
177 | * @entry may no longer be the entry at the index in the mapping. |
178 | * The important information it's conveying is whether the entry at | |
179 | * this index used to be a PMD entry. | |
e30331ff | 180 | */ |
698ab77a VG |
181 | static void dax_wake_entry(struct xa_state *xas, void *entry, |
182 | enum dax_wake_mode mode) | |
e30331ff RZ |
183 | { |
184 | struct exceptional_entry_key key; | |
185 | wait_queue_head_t *wq; | |
186 | ||
b15cd800 | 187 | wq = dax_entry_waitqueue(xas, entry, &key); |
e30331ff RZ |
188 | |
189 | /* | |
190 | * Checking for locked entry and prepare_to_wait_exclusive() happens | |
b93b0163 | 191 | * under the i_pages lock, ditto for entry handling in our callers. |
e30331ff RZ |
192 | * So at this point all tasks that could have seen our entry locked |
193 | * must be in the waitqueue and the following check will see them. | |
194 | */ | |
195 | if (waitqueue_active(wq)) | |
698ab77a | 196 | __wake_up(wq, TASK_NORMAL, mode == WAKE_ALL ? 0 : 1, &key); |
e30331ff RZ |
197 | } |
198 | ||
cfc93c6c MW |
199 | /* |
200 | * Look up entry in page cache, wait for it to become unlocked if it | |
201 | * is a DAX entry and return it. The caller must subsequently call | |
202 | * put_unlocked_entry() if it did not lock the entry or dax_unlock_entry() | |
23c84eb7 MWO |
203 | * if it did. The entry returned may have a larger order than @order. |
204 | * If @order is larger than the order of the entry found in i_pages, this | |
205 | * function returns a dax_is_conflict entry. | |
cfc93c6c MW |
206 | * |
207 | * Must be called with the i_pages lock held. | |
208 | */ | |
23c84eb7 | 209 | static void *get_unlocked_entry(struct xa_state *xas, unsigned int order) |
cfc93c6c MW |
210 | { |
211 | void *entry; | |
212 | struct wait_exceptional_entry_queue ewait; | |
213 | wait_queue_head_t *wq; | |
214 | ||
215 | init_wait(&ewait.wait); | |
216 | ewait.wait.func = wake_exceptional_entry_func; | |
217 | ||
218 | for (;;) { | |
0e40de03 | 219 | entry = xas_find_conflict(xas); |
6370740e DW |
220 | if (!entry || WARN_ON_ONCE(!xa_is_value(entry))) |
221 | return entry; | |
23c84eb7 MWO |
222 | if (dax_entry_order(entry) < order) |
223 | return XA_RETRY_ENTRY; | |
6370740e | 224 | if (!dax_is_locked(entry)) |
cfc93c6c MW |
225 | return entry; |
226 | ||
b15cd800 | 227 | wq = dax_entry_waitqueue(xas, entry, &ewait.key); |
cfc93c6c MW |
228 | prepare_to_wait_exclusive(wq, &ewait.wait, |
229 | TASK_UNINTERRUPTIBLE); | |
230 | xas_unlock_irq(xas); | |
231 | xas_reset(xas); | |
232 | schedule(); | |
233 | finish_wait(wq, &ewait.wait); | |
234 | xas_lock_irq(xas); | |
235 | } | |
236 | } | |
237 | ||
55e56f06 MW |
238 | /* |
239 | * The only thing keeping the address space around is the i_pages lock | |
240 | * (it's cycled in clear_inode() after removing the entries from i_pages) | |
241 | * After we call xas_unlock_irq(), we cannot touch xas->xa. | |
242 | */ | |
243 | static void wait_entry_unlocked(struct xa_state *xas, void *entry) | |
244 | { | |
245 | struct wait_exceptional_entry_queue ewait; | |
246 | wait_queue_head_t *wq; | |
247 | ||
248 | init_wait(&ewait.wait); | |
249 | ewait.wait.func = wake_exceptional_entry_func; | |
250 | ||
251 | wq = dax_entry_waitqueue(xas, entry, &ewait.key); | |
d8a70641 DW |
252 | /* |
253 | * Unlike get_unlocked_entry() there is no guarantee that this | |
254 | * path ever successfully retrieves an unlocked entry before an | |
255 | * inode dies. Perform a non-exclusive wait in case this path | |
256 | * never successfully performs its own wake up. | |
257 | */ | |
258 | prepare_to_wait(wq, &ewait.wait, TASK_UNINTERRUPTIBLE); | |
55e56f06 MW |
259 | xas_unlock_irq(xas); |
260 | schedule(); | |
261 | finish_wait(wq, &ewait.wait); | |
55e56f06 MW |
262 | } |
263 | ||
4c3d043d VG |
264 | static void put_unlocked_entry(struct xa_state *xas, void *entry, |
265 | enum dax_wake_mode mode) | |
cfc93c6c | 266 | { |
61c30c98 | 267 | if (entry && !dax_is_conflict(entry)) |
4c3d043d | 268 | dax_wake_entry(xas, entry, mode); |
cfc93c6c MW |
269 | } |
270 | ||
271 | /* | |
272 | * We used the xa_state to get the entry, but then we locked the entry and | |
273 | * dropped the xa_lock, so we know the xa_state is stale and must be reset | |
274 | * before use. | |
275 | */ | |
276 | static void dax_unlock_entry(struct xa_state *xas, void *entry) | |
277 | { | |
278 | void *old; | |
279 | ||
7ae2ea7d | 280 | BUG_ON(dax_is_locked(entry)); |
cfc93c6c MW |
281 | xas_reset(xas); |
282 | xas_lock_irq(xas); | |
283 | old = xas_store(xas, entry); | |
284 | xas_unlock_irq(xas); | |
285 | BUG_ON(!dax_is_locked(old)); | |
698ab77a | 286 | dax_wake_entry(xas, entry, WAKE_NEXT); |
cfc93c6c MW |
287 | } |
288 | ||
289 | /* | |
290 | * Return: The entry stored at this location before it was locked. | |
291 | */ | |
292 | static void *dax_lock_entry(struct xa_state *xas, void *entry) | |
293 | { | |
294 | unsigned long v = xa_to_value(entry); | |
295 | return xas_store(xas, xa_mk_value(v | DAX_LOCKED)); | |
296 | } | |
297 | ||
d2c997c0 DW |
298 | static unsigned long dax_entry_size(void *entry) |
299 | { | |
300 | if (dax_is_zero_entry(entry)) | |
301 | return 0; | |
302 | else if (dax_is_empty_entry(entry)) | |
303 | return 0; | |
304 | else if (dax_is_pmd_entry(entry)) | |
305 | return PMD_SIZE; | |
306 | else | |
307 | return PAGE_SIZE; | |
308 | } | |
309 | ||
a77d19f4 | 310 | static unsigned long dax_end_pfn(void *entry) |
d2c997c0 | 311 | { |
a77d19f4 | 312 | return dax_to_pfn(entry) + dax_entry_size(entry) / PAGE_SIZE; |
d2c997c0 DW |
313 | } |
314 | ||
315 | /* | |
316 | * Iterate through all mapped pfns represented by an entry, i.e. skip | |
317 | * 'empty' and 'zero' entries. | |
318 | */ | |
319 | #define for_each_mapped_pfn(entry, pfn) \ | |
a77d19f4 MW |
320 | for (pfn = dax_to_pfn(entry); \ |
321 | pfn < dax_end_pfn(entry); pfn++) | |
d2c997c0 | 322 | |
16900426 | 323 | static inline bool dax_page_is_shared(struct page *page) |
6061b69b | 324 | { |
16900426 | 325 | return page->mapping == PAGE_MAPPING_DAX_SHARED; |
6061b69b SR |
326 | } |
327 | ||
73449daf | 328 | /* |
16900426 SR |
329 | * Set the page->mapping with PAGE_MAPPING_DAX_SHARED flag, increase the |
330 | * refcount. | |
6061b69b | 331 | */ |
16900426 | 332 | static inline void dax_page_share_get(struct page *page) |
6061b69b | 333 | { |
16900426 | 334 | if (page->mapping != PAGE_MAPPING_DAX_SHARED) { |
6061b69b SR |
335 | /* |
336 | * Reset the index if the page was already mapped | |
337 | * regularly before. | |
338 | */ | |
339 | if (page->mapping) | |
16900426 SR |
340 | page->share = 1; |
341 | page->mapping = PAGE_MAPPING_DAX_SHARED; | |
6061b69b | 342 | } |
16900426 SR |
343 | page->share++; |
344 | } | |
345 | ||
346 | static inline unsigned long dax_page_share_put(struct page *page) | |
347 | { | |
348 | return --page->share; | |
6061b69b SR |
349 | } |
350 | ||
351 | /* | |
16900426 | 352 | * When it is called in dax_insert_entry(), the shared flag will indicate that |
6061b69b | 353 | * whether this entry is shared by multiple files. If so, set the page->mapping |
16900426 | 354 | * PAGE_MAPPING_DAX_SHARED, and use page->share as refcount. |
73449daf DW |
355 | */ |
356 | static void dax_associate_entry(void *entry, struct address_space *mapping, | |
16900426 | 357 | struct vm_area_struct *vma, unsigned long address, bool shared) |
d2c997c0 | 358 | { |
73449daf DW |
359 | unsigned long size = dax_entry_size(entry), pfn, index; |
360 | int i = 0; | |
d2c997c0 DW |
361 | |
362 | if (IS_ENABLED(CONFIG_FS_DAX_LIMITED)) | |
363 | return; | |
364 | ||
73449daf | 365 | index = linear_page_index(vma, address & ~(size - 1)); |
d2c997c0 DW |
366 | for_each_mapped_pfn(entry, pfn) { |
367 | struct page *page = pfn_to_page(pfn); | |
368 | ||
16900426 SR |
369 | if (shared) { |
370 | dax_page_share_get(page); | |
6061b69b SR |
371 | } else { |
372 | WARN_ON_ONCE(page->mapping); | |
373 | page->mapping = mapping; | |
374 | page->index = index + i++; | |
375 | } | |
d2c997c0 DW |
376 | } |
377 | } | |
378 | ||
379 | static void dax_disassociate_entry(void *entry, struct address_space *mapping, | |
380 | bool trunc) | |
381 | { | |
382 | unsigned long pfn; | |
383 | ||
384 | if (IS_ENABLED(CONFIG_FS_DAX_LIMITED)) | |
385 | return; | |
386 | ||
387 | for_each_mapped_pfn(entry, pfn) { | |
388 | struct page *page = pfn_to_page(pfn); | |
389 | ||
390 | WARN_ON_ONCE(trunc && page_ref_count(page) > 1); | |
16900426 SR |
391 | if (dax_page_is_shared(page)) { |
392 | /* keep the shared flag if this page is still shared */ | |
393 | if (dax_page_share_put(page) > 0) | |
6061b69b SR |
394 | continue; |
395 | } else | |
396 | WARN_ON_ONCE(page->mapping && page->mapping != mapping); | |
d2c997c0 | 397 | page->mapping = NULL; |
73449daf | 398 | page->index = 0; |
d2c997c0 DW |
399 | } |
400 | } | |
401 | ||
5fac7408 DW |
402 | static struct page *dax_busy_page(void *entry) |
403 | { | |
404 | unsigned long pfn; | |
405 | ||
406 | for_each_mapped_pfn(entry, pfn) { | |
407 | struct page *page = pfn_to_page(pfn); | |
408 | ||
409 | if (page_ref_count(page) > 1) | |
410 | return page; | |
411 | } | |
412 | return NULL; | |
413 | } | |
414 | ||
91e79d22 MWO |
415 | /** |
416 | * dax_lock_folio - Lock the DAX entry corresponding to a folio | |
417 | * @folio: The folio whose entry we want to lock | |
c5bbd451 MW |
418 | * |
419 | * Context: Process context. | |
91e79d22 | 420 | * Return: A cookie to pass to dax_unlock_folio() or 0 if the entry could |
27359fd6 | 421 | * not be locked. |
c5bbd451 | 422 | */ |
91e79d22 | 423 | dax_entry_t dax_lock_folio(struct folio *folio) |
c2a7d2a1 | 424 | { |
9f32d221 MW |
425 | XA_STATE(xas, NULL, 0); |
426 | void *entry; | |
c2a7d2a1 | 427 | |
91e79d22 | 428 | /* Ensure folio->mapping isn't freed while we look at it */ |
c5bbd451 | 429 | rcu_read_lock(); |
c2a7d2a1 | 430 | for (;;) { |
91e79d22 | 431 | struct address_space *mapping = READ_ONCE(folio->mapping); |
c2a7d2a1 | 432 | |
27359fd6 | 433 | entry = NULL; |
c93db7bb | 434 | if (!mapping || !dax_mapping(mapping)) |
c5bbd451 | 435 | break; |
c2a7d2a1 DW |
436 | |
437 | /* | |
438 | * In the device-dax case there's no need to lock, a | |
439 | * struct dev_pagemap pin is sufficient to keep the | |
440 | * inode alive, and we assume we have dev_pagemap pin | |
441 | * otherwise we would not have a valid pfn_to_page() | |
442 | * translation. | |
443 | */ | |
27359fd6 | 444 | entry = (void *)~0UL; |
9f32d221 | 445 | if (S_ISCHR(mapping->host->i_mode)) |
c5bbd451 | 446 | break; |
c2a7d2a1 | 447 | |
9f32d221 MW |
448 | xas.xa = &mapping->i_pages; |
449 | xas_lock_irq(&xas); | |
91e79d22 | 450 | if (mapping != folio->mapping) { |
9f32d221 | 451 | xas_unlock_irq(&xas); |
c2a7d2a1 DW |
452 | continue; |
453 | } | |
91e79d22 | 454 | xas_set(&xas, folio->index); |
9f32d221 MW |
455 | entry = xas_load(&xas); |
456 | if (dax_is_locked(entry)) { | |
c5bbd451 | 457 | rcu_read_unlock(); |
55e56f06 | 458 | wait_entry_unlocked(&xas, entry); |
c5bbd451 | 459 | rcu_read_lock(); |
6d7cd8c1 | 460 | continue; |
c2a7d2a1 | 461 | } |
9f32d221 MW |
462 | dax_lock_entry(&xas, entry); |
463 | xas_unlock_irq(&xas); | |
c5bbd451 | 464 | break; |
c2a7d2a1 | 465 | } |
c5bbd451 | 466 | rcu_read_unlock(); |
27359fd6 | 467 | return (dax_entry_t)entry; |
c2a7d2a1 DW |
468 | } |
469 | ||
91e79d22 | 470 | void dax_unlock_folio(struct folio *folio, dax_entry_t cookie) |
c2a7d2a1 | 471 | { |
91e79d22 MWO |
472 | struct address_space *mapping = folio->mapping; |
473 | XA_STATE(xas, &mapping->i_pages, folio->index); | |
c2a7d2a1 | 474 | |
9f32d221 | 475 | if (S_ISCHR(mapping->host->i_mode)) |
c2a7d2a1 DW |
476 | return; |
477 | ||
27359fd6 | 478 | dax_unlock_entry(&xas, (void *)cookie); |
c2a7d2a1 DW |
479 | } |
480 | ||
2f437eff SR |
481 | /* |
482 | * dax_lock_mapping_entry - Lock the DAX entry corresponding to a mapping | |
483 | * @mapping: the file's mapping whose entry we want to lock | |
484 | * @index: the offset within this file | |
485 | * @page: output the dax page corresponding to this dax entry | |
486 | * | |
487 | * Return: A cookie to pass to dax_unlock_mapping_entry() or 0 if the entry | |
488 | * could not be locked. | |
489 | */ | |
490 | dax_entry_t dax_lock_mapping_entry(struct address_space *mapping, pgoff_t index, | |
491 | struct page **page) | |
492 | { | |
493 | XA_STATE(xas, NULL, 0); | |
494 | void *entry; | |
495 | ||
496 | rcu_read_lock(); | |
497 | for (;;) { | |
498 | entry = NULL; | |
499 | if (!dax_mapping(mapping)) | |
500 | break; | |
501 | ||
502 | xas.xa = &mapping->i_pages; | |
503 | xas_lock_irq(&xas); | |
504 | xas_set(&xas, index); | |
505 | entry = xas_load(&xas); | |
506 | if (dax_is_locked(entry)) { | |
507 | rcu_read_unlock(); | |
508 | wait_entry_unlocked(&xas, entry); | |
509 | rcu_read_lock(); | |
510 | continue; | |
511 | } | |
512 | if (!entry || | |
513 | dax_is_zero_entry(entry) || dax_is_empty_entry(entry)) { | |
514 | /* | |
515 | * Because we are looking for entry from file's mapping | |
516 | * and index, so the entry may not be inserted for now, | |
517 | * or even a zero/empty entry. We don't think this is | |
518 | * an error case. So, return a special value and do | |
519 | * not output @page. | |
520 | */ | |
521 | entry = (void *)~0UL; | |
522 | } else { | |
523 | *page = pfn_to_page(dax_to_pfn(entry)); | |
524 | dax_lock_entry(&xas, entry); | |
525 | } | |
526 | xas_unlock_irq(&xas); | |
527 | break; | |
528 | } | |
529 | rcu_read_unlock(); | |
530 | return (dax_entry_t)entry; | |
531 | } | |
532 | ||
533 | void dax_unlock_mapping_entry(struct address_space *mapping, pgoff_t index, | |
534 | dax_entry_t cookie) | |
535 | { | |
536 | XA_STATE(xas, &mapping->i_pages, index); | |
537 | ||
538 | if (cookie == ~0UL) | |
539 | return; | |
540 | ||
541 | dax_unlock_entry(&xas, (void *)cookie); | |
542 | } | |
543 | ||
ac401cc7 | 544 | /* |
a77d19f4 MW |
545 | * Find page cache entry at given index. If it is a DAX entry, return it |
546 | * with the entry locked. If the page cache doesn't contain an entry at | |
547 | * that index, add a locked empty entry. | |
ac401cc7 | 548 | * |
3159f943 | 549 | * When requesting an entry with size DAX_PMD, grab_mapping_entry() will |
b15cd800 MW |
550 | * either return that locked entry or will return VM_FAULT_FALLBACK. |
551 | * This will happen if there are any PTE entries within the PMD range | |
552 | * that we are requesting. | |
642261ac | 553 | * |
b15cd800 MW |
554 | * We always favor PTE entries over PMD entries. There isn't a flow where we |
555 | * evict PTE entries in order to 'upgrade' them to a PMD entry. A PMD | |
556 | * insertion will fail if it finds any PTE entries already in the tree, and a | |
557 | * PTE insertion will cause an existing PMD entry to be unmapped and | |
558 | * downgraded to PTE entries. This happens for both PMD zero pages as | |
559 | * well as PMD empty entries. | |
642261ac | 560 | * |
b15cd800 MW |
561 | * The exception to this downgrade path is for PMD entries that have |
562 | * real storage backing them. We will leave these real PMD entries in | |
563 | * the tree, and PTE writes will simply dirty the entire PMD entry. | |
642261ac | 564 | * |
ac401cc7 JK |
565 | * Note: Unlike filemap_fault() we don't honor FAULT_FLAG_RETRY flags. For |
566 | * persistent memory the benefit is doubtful. We can add that later if we can | |
567 | * show it helps. | |
b15cd800 MW |
568 | * |
569 | * On error, this function does not return an ERR_PTR. Instead it returns | |
570 | * a VM_FAULT code, encoded as an xarray internal entry. The ERR_PTR values | |
571 | * overlap with xarray value entries. | |
ac401cc7 | 572 | */ |
b15cd800 | 573 | static void *grab_mapping_entry(struct xa_state *xas, |
23c84eb7 | 574 | struct address_space *mapping, unsigned int order) |
ac401cc7 | 575 | { |
b15cd800 | 576 | unsigned long index = xas->xa_index; |
1a14e377 | 577 | bool pmd_downgrade; /* splitting PMD entry into PTE entries? */ |
b15cd800 | 578 | void *entry; |
642261ac | 579 | |
b15cd800 | 580 | retry: |
1a14e377 | 581 | pmd_downgrade = false; |
b15cd800 | 582 | xas_lock_irq(xas); |
23c84eb7 | 583 | entry = get_unlocked_entry(xas, order); |
91d25ba8 | 584 | |
642261ac | 585 | if (entry) { |
23c84eb7 MWO |
586 | if (dax_is_conflict(entry)) |
587 | goto fallback; | |
0e40de03 | 588 | if (!xa_is_value(entry)) { |
49688e65 | 589 | xas_set_err(xas, -EIO); |
b15cd800 MW |
590 | goto out_unlock; |
591 | } | |
592 | ||
23c84eb7 | 593 | if (order == 0) { |
91d25ba8 | 594 | if (dax_is_pmd_entry(entry) && |
642261ac RZ |
595 | (dax_is_zero_entry(entry) || |
596 | dax_is_empty_entry(entry))) { | |
597 | pmd_downgrade = true; | |
598 | } | |
599 | } | |
600 | } | |
601 | ||
b15cd800 MW |
602 | if (pmd_downgrade) { |
603 | /* | |
604 | * Make sure 'entry' remains valid while we drop | |
605 | * the i_pages lock. | |
606 | */ | |
607 | dax_lock_entry(xas, entry); | |
642261ac | 608 | |
642261ac RZ |
609 | /* |
610 | * Besides huge zero pages the only other thing that gets | |
611 | * downgraded are empty entries which don't need to be | |
612 | * unmapped. | |
613 | */ | |
b15cd800 MW |
614 | if (dax_is_zero_entry(entry)) { |
615 | xas_unlock_irq(xas); | |
616 | unmap_mapping_pages(mapping, | |
617 | xas->xa_index & ~PG_PMD_COLOUR, | |
618 | PG_PMD_NR, false); | |
619 | xas_reset(xas); | |
620 | xas_lock_irq(xas); | |
e11f8b7b RZ |
621 | } |
622 | ||
b15cd800 MW |
623 | dax_disassociate_entry(entry, mapping, false); |
624 | xas_store(xas, NULL); /* undo the PMD join */ | |
698ab77a | 625 | dax_wake_entry(xas, entry, WAKE_ALL); |
7f0e07fb | 626 | mapping->nrpages -= PG_PMD_NR; |
b15cd800 MW |
627 | entry = NULL; |
628 | xas_set(xas, index); | |
629 | } | |
642261ac | 630 | |
b15cd800 MW |
631 | if (entry) { |
632 | dax_lock_entry(xas, entry); | |
633 | } else { | |
23c84eb7 MWO |
634 | unsigned long flags = DAX_EMPTY; |
635 | ||
636 | if (order > 0) | |
637 | flags |= DAX_PMD; | |
638 | entry = dax_make_entry(pfn_to_pfn_t(0), flags); | |
b15cd800 MW |
639 | dax_lock_entry(xas, entry); |
640 | if (xas_error(xas)) | |
641 | goto out_unlock; | |
7f0e07fb | 642 | mapping->nrpages += 1UL << order; |
ac401cc7 | 643 | } |
b15cd800 MW |
644 | |
645 | out_unlock: | |
646 | xas_unlock_irq(xas); | |
647 | if (xas_nomem(xas, mapping_gfp_mask(mapping) & ~__GFP_HIGHMEM)) | |
648 | goto retry; | |
649 | if (xas->xa_node == XA_ERROR(-ENOMEM)) | |
650 | return xa_mk_internal(VM_FAULT_OOM); | |
651 | if (xas_error(xas)) | |
652 | return xa_mk_internal(VM_FAULT_SIGBUS); | |
e3ad61c6 | 653 | return entry; |
b15cd800 MW |
654 | fallback: |
655 | xas_unlock_irq(xas); | |
656 | return xa_mk_internal(VM_FAULT_FALLBACK); | |
ac401cc7 JK |
657 | } |
658 | ||
5fac7408 | 659 | /** |
6bbdd563 | 660 | * dax_layout_busy_page_range - find first pinned page in @mapping |
5fac7408 | 661 | * @mapping: address space to scan for a page with ref count > 1 |
6bbdd563 VG |
662 | * @start: Starting offset. Page containing 'start' is included. |
663 | * @end: End offset. Page containing 'end' is included. If 'end' is LLONG_MAX, | |
664 | * pages from 'start' till the end of file are included. | |
5fac7408 DW |
665 | * |
666 | * DAX requires ZONE_DEVICE mapped pages. These pages are never | |
667 | * 'onlined' to the page allocator so they are considered idle when | |
668 | * page->count == 1. A filesystem uses this interface to determine if | |
669 | * any page in the mapping is busy, i.e. for DMA, or other | |
670 | * get_user_pages() usages. | |
671 | * | |
672 | * It is expected that the filesystem is holding locks to block the | |
673 | * establishment of new mappings in this address_space. I.e. it expects | |
674 | * to be able to run unmap_mapping_range() and subsequently not race | |
675 | * mapping_mapped() becoming true. | |
676 | */ | |
6bbdd563 VG |
677 | struct page *dax_layout_busy_page_range(struct address_space *mapping, |
678 | loff_t start, loff_t end) | |
5fac7408 | 679 | { |
084a8990 MW |
680 | void *entry; |
681 | unsigned int scanned = 0; | |
5fac7408 | 682 | struct page *page = NULL; |
6bbdd563 VG |
683 | pgoff_t start_idx = start >> PAGE_SHIFT; |
684 | pgoff_t end_idx; | |
685 | XA_STATE(xas, &mapping->i_pages, start_idx); | |
5fac7408 DW |
686 | |
687 | /* | |
688 | * In the 'limited' case get_user_pages() for dax is disabled. | |
689 | */ | |
690 | if (IS_ENABLED(CONFIG_FS_DAX_LIMITED)) | |
691 | return NULL; | |
692 | ||
693 | if (!dax_mapping(mapping) || !mapping_mapped(mapping)) | |
694 | return NULL; | |
695 | ||
6bbdd563 VG |
696 | /* If end == LLONG_MAX, all pages from start to till end of file */ |
697 | if (end == LLONG_MAX) | |
698 | end_idx = ULONG_MAX; | |
699 | else | |
700 | end_idx = end >> PAGE_SHIFT; | |
5fac7408 DW |
701 | /* |
702 | * If we race get_user_pages_fast() here either we'll see the | |
084a8990 | 703 | * elevated page count in the iteration and wait, or |
5fac7408 DW |
704 | * get_user_pages_fast() will see that the page it took a reference |
705 | * against is no longer mapped in the page tables and bail to the | |
706 | * get_user_pages() slow path. The slow path is protected by | |
707 | * pte_lock() and pmd_lock(). New references are not taken without | |
6bbdd563 | 708 | * holding those locks, and unmap_mapping_pages() will not zero the |
5fac7408 DW |
709 | * pte or pmd without holding the respective lock, so we are |
710 | * guaranteed to either see new references or prevent new | |
711 | * references from being established. | |
712 | */ | |
6bbdd563 | 713 | unmap_mapping_pages(mapping, start_idx, end_idx - start_idx + 1, 0); |
5fac7408 | 714 | |
084a8990 | 715 | xas_lock_irq(&xas); |
6bbdd563 | 716 | xas_for_each(&xas, entry, end_idx) { |
084a8990 MW |
717 | if (WARN_ON_ONCE(!xa_is_value(entry))) |
718 | continue; | |
719 | if (unlikely(dax_is_locked(entry))) | |
23c84eb7 | 720 | entry = get_unlocked_entry(&xas, 0); |
084a8990 MW |
721 | if (entry) |
722 | page = dax_busy_page(entry); | |
4c3d043d | 723 | put_unlocked_entry(&xas, entry, WAKE_NEXT); |
5fac7408 DW |
724 | if (page) |
725 | break; | |
084a8990 MW |
726 | if (++scanned % XA_CHECK_SCHED) |
727 | continue; | |
728 | ||
729 | xas_pause(&xas); | |
730 | xas_unlock_irq(&xas); | |
731 | cond_resched(); | |
732 | xas_lock_irq(&xas); | |
5fac7408 | 733 | } |
084a8990 | 734 | xas_unlock_irq(&xas); |
5fac7408 DW |
735 | return page; |
736 | } | |
6bbdd563 VG |
737 | EXPORT_SYMBOL_GPL(dax_layout_busy_page_range); |
738 | ||
739 | struct page *dax_layout_busy_page(struct address_space *mapping) | |
740 | { | |
741 | return dax_layout_busy_page_range(mapping, 0, LLONG_MAX); | |
742 | } | |
5fac7408 DW |
743 | EXPORT_SYMBOL_GPL(dax_layout_busy_page); |
744 | ||
a77d19f4 | 745 | static int __dax_invalidate_entry(struct address_space *mapping, |
c6dcf52c JK |
746 | pgoff_t index, bool trunc) |
747 | { | |
07f2d89c | 748 | XA_STATE(xas, &mapping->i_pages, index); |
c6dcf52c JK |
749 | int ret = 0; |
750 | void *entry; | |
c6dcf52c | 751 | |
07f2d89c | 752 | xas_lock_irq(&xas); |
23c84eb7 | 753 | entry = get_unlocked_entry(&xas, 0); |
3159f943 | 754 | if (!entry || WARN_ON_ONCE(!xa_is_value(entry))) |
c6dcf52c JK |
755 | goto out; |
756 | if (!trunc && | |
07f2d89c MW |
757 | (xas_get_mark(&xas, PAGECACHE_TAG_DIRTY) || |
758 | xas_get_mark(&xas, PAGECACHE_TAG_TOWRITE))) | |
c6dcf52c | 759 | goto out; |
d2c997c0 | 760 | dax_disassociate_entry(entry, mapping, trunc); |
07f2d89c | 761 | xas_store(&xas, NULL); |
7f0e07fb | 762 | mapping->nrpages -= 1UL << dax_entry_order(entry); |
c6dcf52c JK |
763 | ret = 1; |
764 | out: | |
23738832 | 765 | put_unlocked_entry(&xas, entry, WAKE_ALL); |
07f2d89c | 766 | xas_unlock_irq(&xas); |
c6dcf52c JK |
767 | return ret; |
768 | } | |
07f2d89c | 769 | |
f76b3a32 SR |
770 | static int __dax_clear_dirty_range(struct address_space *mapping, |
771 | pgoff_t start, pgoff_t end) | |
772 | { | |
773 | XA_STATE(xas, &mapping->i_pages, start); | |
774 | unsigned int scanned = 0; | |
775 | void *entry; | |
776 | ||
777 | xas_lock_irq(&xas); | |
778 | xas_for_each(&xas, entry, end) { | |
779 | entry = get_unlocked_entry(&xas, 0); | |
780 | xas_clear_mark(&xas, PAGECACHE_TAG_DIRTY); | |
781 | xas_clear_mark(&xas, PAGECACHE_TAG_TOWRITE); | |
782 | put_unlocked_entry(&xas, entry, WAKE_NEXT); | |
783 | ||
784 | if (++scanned % XA_CHECK_SCHED) | |
785 | continue; | |
786 | ||
787 | xas_pause(&xas); | |
788 | xas_unlock_irq(&xas); | |
789 | cond_resched(); | |
790 | xas_lock_irq(&xas); | |
791 | } | |
792 | xas_unlock_irq(&xas); | |
793 | ||
794 | return 0; | |
795 | } | |
796 | ||
ac401cc7 | 797 | /* |
3159f943 MW |
798 | * Delete DAX entry at @index from @mapping. Wait for it |
799 | * to be unlocked before deleting it. | |
ac401cc7 JK |
800 | */ |
801 | int dax_delete_mapping_entry(struct address_space *mapping, pgoff_t index) | |
802 | { | |
a77d19f4 | 803 | int ret = __dax_invalidate_entry(mapping, index, true); |
ac401cc7 | 804 | |
ac401cc7 JK |
805 | /* |
806 | * This gets called from truncate / punch_hole path. As such, the caller | |
807 | * must hold locks protecting against concurrent modifications of the | |
a77d19f4 | 808 | * page cache (usually fs-private i_mmap_sem for writing). Since the |
3159f943 | 809 | * caller has seen a DAX entry for this index, we better find it |
ac401cc7 JK |
810 | * at that index as well... |
811 | */ | |
c6dcf52c JK |
812 | WARN_ON_ONCE(!ret); |
813 | return ret; | |
814 | } | |
815 | ||
c6dcf52c | 816 | /* |
3159f943 | 817 | * Invalidate DAX entry if it is clean. |
c6dcf52c JK |
818 | */ |
819 | int dax_invalidate_mapping_entry_sync(struct address_space *mapping, | |
820 | pgoff_t index) | |
821 | { | |
a77d19f4 | 822 | return __dax_invalidate_entry(mapping, index, false); |
ac401cc7 JK |
823 | } |
824 | ||
60696eb2 | 825 | static pgoff_t dax_iomap_pgoff(const struct iomap *iomap, loff_t pos) |
f7ca90b1 | 826 | { |
de205114 | 827 | return PHYS_PFN(iomap->addr + (pos & PAGE_MASK) - iomap->offset); |
429f8de7 CH |
828 | } |
829 | ||
830 | static int copy_cow_page_dax(struct vm_fault *vmf, const struct iomap_iter *iter) | |
831 | { | |
60696eb2 | 832 | pgoff_t pgoff = dax_iomap_pgoff(&iter->iomap, iter->pos); |
cccbce67 | 833 | void *vto, *kaddr; |
cccbce67 DW |
834 | long rc; |
835 | int id; | |
836 | ||
cccbce67 | 837 | id = dax_read_lock(); |
e511c4a3 JC |
838 | rc = dax_direct_access(iter->iomap.dax_dev, pgoff, 1, DAX_ACCESS, |
839 | &kaddr, NULL); | |
cccbce67 DW |
840 | if (rc < 0) { |
841 | dax_read_unlock(id); | |
842 | return rc; | |
843 | } | |
429f8de7 CH |
844 | vto = kmap_atomic(vmf->cow_page); |
845 | copy_user_page(vto, kaddr, vmf->address, vmf->cow_page); | |
f7ca90b1 | 846 | kunmap_atomic(vto); |
cccbce67 | 847 | dax_read_unlock(id); |
f7ca90b1 MW |
848 | return 0; |
849 | } | |
850 | ||
e5d6df73 SR |
851 | /* |
852 | * MAP_SYNC on a dax mapping guarantees dirty metadata is | |
853 | * flushed on write-faults (non-cow), but not read-faults. | |
854 | */ | |
855 | static bool dax_fault_is_synchronous(const struct iomap_iter *iter, | |
856 | struct vm_area_struct *vma) | |
857 | { | |
858 | return (iter->flags & IOMAP_WRITE) && (vma->vm_flags & VM_SYNC) && | |
859 | (iter->iomap.flags & IOMAP_F_DIRTY); | |
860 | } | |
861 | ||
642261ac RZ |
862 | /* |
863 | * By this point grab_mapping_entry() has ensured that we have a locked entry | |
864 | * of the appropriate size so we don't have to worry about downgrading PMDs to | |
865 | * PTEs. If we happen to be trying to insert a PTE and there is a PMD | |
866 | * already in the tree, we will skip the insertion and just dirty the PMD as | |
867 | * appropriate. | |
868 | */ | |
e5d6df73 SR |
869 | static void *dax_insert_entry(struct xa_state *xas, struct vm_fault *vmf, |
870 | const struct iomap_iter *iter, void *entry, pfn_t pfn, | |
871 | unsigned long flags) | |
9973c98e | 872 | { |
e5d6df73 | 873 | struct address_space *mapping = vmf->vma->vm_file->f_mapping; |
b15cd800 | 874 | void *new_entry = dax_make_entry(pfn, flags); |
c6f0b395 SR |
875 | bool write = iter->flags & IOMAP_WRITE; |
876 | bool dirty = write && !dax_fault_is_synchronous(iter, vmf->vma); | |
877 | bool shared = iter->iomap.flags & IOMAP_F_SHARED; | |
9973c98e | 878 | |
f5b7b748 | 879 | if (dirty) |
d2b2a28e | 880 | __mark_inode_dirty(mapping->host, I_DIRTY_PAGES); |
9973c98e | 881 | |
c6f0b395 | 882 | if (shared || (dax_is_zero_entry(entry) && !(flags & DAX_ZERO_PAGE))) { |
b15cd800 | 883 | unsigned long index = xas->xa_index; |
91d25ba8 RZ |
884 | /* we are replacing a zero page with block mapping */ |
885 | if (dax_is_pmd_entry(entry)) | |
977fbdcd | 886 | unmap_mapping_pages(mapping, index & ~PG_PMD_COLOUR, |
b15cd800 | 887 | PG_PMD_NR, false); |
91d25ba8 | 888 | else /* pte entry */ |
b15cd800 | 889 | unmap_mapping_pages(mapping, index, 1, false); |
9973c98e RZ |
890 | } |
891 | ||
b15cd800 MW |
892 | xas_reset(xas); |
893 | xas_lock_irq(xas); | |
c6f0b395 | 894 | if (shared || dax_is_zero_entry(entry) || dax_is_empty_entry(entry)) { |
1571c029 JK |
895 | void *old; |
896 | ||
d2c997c0 | 897 | dax_disassociate_entry(entry, mapping, false); |
6061b69b | 898 | dax_associate_entry(new_entry, mapping, vmf->vma, vmf->address, |
c6f0b395 | 899 | shared); |
642261ac | 900 | /* |
a77d19f4 | 901 | * Only swap our new entry into the page cache if the current |
642261ac | 902 | * entry is a zero page or an empty entry. If a normal PTE or |
a77d19f4 | 903 | * PMD entry is already in the cache, we leave it alone. This |
642261ac RZ |
904 | * means that if we are trying to insert a PTE and the |
905 | * existing entry is a PMD, we will just leave the PMD in the | |
906 | * tree and dirty it if necessary. | |
907 | */ | |
1571c029 | 908 | old = dax_lock_entry(xas, new_entry); |
b15cd800 MW |
909 | WARN_ON_ONCE(old != xa_mk_value(xa_to_value(entry) | |
910 | DAX_LOCKED)); | |
91d25ba8 | 911 | entry = new_entry; |
b15cd800 MW |
912 | } else { |
913 | xas_load(xas); /* Walk the xa_state */ | |
9973c98e | 914 | } |
91d25ba8 | 915 | |
f5b7b748 | 916 | if (dirty) |
b15cd800 | 917 | xas_set_mark(xas, PAGECACHE_TAG_DIRTY); |
91d25ba8 | 918 | |
c6f0b395 | 919 | if (write && shared) |
e5d6df73 SR |
920 | xas_set_mark(xas, PAGECACHE_TAG_TOWRITE); |
921 | ||
b15cd800 | 922 | xas_unlock_irq(xas); |
91d25ba8 | 923 | return entry; |
9973c98e RZ |
924 | } |
925 | ||
9fc747f6 MW |
926 | static int dax_writeback_one(struct xa_state *xas, struct dax_device *dax_dev, |
927 | struct address_space *mapping, void *entry) | |
9973c98e | 928 | { |
06083a09 | 929 | unsigned long pfn, index, count, end; |
3fe0791c | 930 | long ret = 0; |
06083a09 | 931 | struct vm_area_struct *vma; |
9973c98e | 932 | |
9973c98e | 933 | /* |
a6abc2c0 JK |
934 | * A page got tagged dirty in DAX mapping? Something is seriously |
935 | * wrong. | |
9973c98e | 936 | */ |
3159f943 | 937 | if (WARN_ON(!xa_is_value(entry))) |
a6abc2c0 | 938 | return -EIO; |
9973c98e | 939 | |
9fc747f6 MW |
940 | if (unlikely(dax_is_locked(entry))) { |
941 | void *old_entry = entry; | |
942 | ||
23c84eb7 | 943 | entry = get_unlocked_entry(xas, 0); |
9fc747f6 MW |
944 | |
945 | /* Entry got punched out / reallocated? */ | |
946 | if (!entry || WARN_ON_ONCE(!xa_is_value(entry))) | |
947 | goto put_unlocked; | |
948 | /* | |
949 | * Entry got reallocated elsewhere? No need to writeback. | |
950 | * We have to compare pfns as we must not bail out due to | |
951 | * difference in lockbit or entry type. | |
952 | */ | |
953 | if (dax_to_pfn(old_entry) != dax_to_pfn(entry)) | |
954 | goto put_unlocked; | |
955 | if (WARN_ON_ONCE(dax_is_empty_entry(entry) || | |
956 | dax_is_zero_entry(entry))) { | |
957 | ret = -EIO; | |
958 | goto put_unlocked; | |
959 | } | |
960 | ||
961 | /* Another fsync thread may have already done this entry */ | |
962 | if (!xas_get_mark(xas, PAGECACHE_TAG_TOWRITE)) | |
963 | goto put_unlocked; | |
9973c98e RZ |
964 | } |
965 | ||
a6abc2c0 | 966 | /* Lock the entry to serialize with page faults */ |
9fc747f6 MW |
967 | dax_lock_entry(xas, entry); |
968 | ||
a6abc2c0 JK |
969 | /* |
970 | * We can clear the tag now but we have to be careful so that concurrent | |
971 | * dax_writeback_one() calls for the same index cannot finish before we | |
972 | * actually flush the caches. This is achieved as the calls will look | |
b93b0163 MW |
973 | * at the entry only under the i_pages lock and once they do that |
974 | * they will see the entry locked and wait for it to unlock. | |
a6abc2c0 | 975 | */ |
9fc747f6 MW |
976 | xas_clear_mark(xas, PAGECACHE_TAG_TOWRITE); |
977 | xas_unlock_irq(xas); | |
a6abc2c0 | 978 | |
642261ac | 979 | /* |
e4b3448b MW |
980 | * If dax_writeback_mapping_range() was given a wbc->range_start |
981 | * in the middle of a PMD, the 'index' we use needs to be | |
982 | * aligned to the start of the PMD. | |
3fe0791c DW |
983 | * This allows us to flush for PMD_SIZE and not have to worry about |
984 | * partial PMD writebacks. | |
642261ac | 985 | */ |
a77d19f4 | 986 | pfn = dax_to_pfn(entry); |
e4b3448b MW |
987 | count = 1UL << dax_entry_order(entry); |
988 | index = xas->xa_index & ~(count - 1); | |
06083a09 MS |
989 | end = index + count - 1; |
990 | ||
991 | /* Walk all mappings of a given index of a file and writeprotect them */ | |
992 | i_mmap_lock_read(mapping); | |
993 | vma_interval_tree_foreach(vma, &mapping->i_mmap, index, end) { | |
994 | pfn_mkclean_range(pfn, count, index, vma); | |
995 | cond_resched(); | |
996 | } | |
997 | i_mmap_unlock_read(mapping); | |
cccbce67 | 998 | |
e4b3448b | 999 | dax_flush(dax_dev, page_address(pfn_to_page(pfn)), count * PAGE_SIZE); |
4b4bb46d JK |
1000 | /* |
1001 | * After we have flushed the cache, we can clear the dirty tag. There | |
1002 | * cannot be new dirty data in the pfn after the flush has completed as | |
1003 | * the pfn mappings are writeprotected and fault waits for mapping | |
1004 | * entry lock. | |
1005 | */ | |
9fc747f6 MW |
1006 | xas_reset(xas); |
1007 | xas_lock_irq(xas); | |
1008 | xas_store(xas, entry); | |
1009 | xas_clear_mark(xas, PAGECACHE_TAG_DIRTY); | |
698ab77a | 1010 | dax_wake_entry(xas, entry, WAKE_NEXT); |
9fc747f6 | 1011 | |
e4b3448b | 1012 | trace_dax_writeback_one(mapping->host, index, count); |
9973c98e RZ |
1013 | return ret; |
1014 | ||
a6abc2c0 | 1015 | put_unlocked: |
4c3d043d | 1016 | put_unlocked_entry(xas, entry, WAKE_NEXT); |
9973c98e RZ |
1017 | return ret; |
1018 | } | |
1019 | ||
1020 | /* | |
1021 | * Flush the mapping to the persistent domain within the byte range of [start, | |
1022 | * end]. This is required by data integrity operations to ensure file data is | |
1023 | * on persistent storage prior to completion of the operation. | |
1024 | */ | |
7f6d5b52 | 1025 | int dax_writeback_mapping_range(struct address_space *mapping, |
3f666c56 | 1026 | struct dax_device *dax_dev, struct writeback_control *wbc) |
9973c98e | 1027 | { |
9fc747f6 | 1028 | XA_STATE(xas, &mapping->i_pages, wbc->range_start >> PAGE_SHIFT); |
9973c98e | 1029 | struct inode *inode = mapping->host; |
9fc747f6 | 1030 | pgoff_t end_index = wbc->range_end >> PAGE_SHIFT; |
9fc747f6 MW |
1031 | void *entry; |
1032 | int ret = 0; | |
1033 | unsigned int scanned = 0; | |
9973c98e RZ |
1034 | |
1035 | if (WARN_ON_ONCE(inode->i_blkbits != PAGE_SHIFT)) | |
1036 | return -EIO; | |
1037 | ||
7716506a | 1038 | if (mapping_empty(mapping) || wbc->sync_mode != WB_SYNC_ALL) |
7f6d5b52 RZ |
1039 | return 0; |
1040 | ||
9fc747f6 | 1041 | trace_dax_writeback_range(inode, xas.xa_index, end_index); |
9973c98e | 1042 | |
9fc747f6 | 1043 | tag_pages_for_writeback(mapping, xas.xa_index, end_index); |
9973c98e | 1044 | |
9fc747f6 MW |
1045 | xas_lock_irq(&xas); |
1046 | xas_for_each_marked(&xas, entry, end_index, PAGECACHE_TAG_TOWRITE) { | |
1047 | ret = dax_writeback_one(&xas, dax_dev, mapping, entry); | |
1048 | if (ret < 0) { | |
1049 | mapping_set_error(mapping, ret); | |
9973c98e | 1050 | break; |
9973c98e | 1051 | } |
9fc747f6 MW |
1052 | if (++scanned % XA_CHECK_SCHED) |
1053 | continue; | |
1054 | ||
1055 | xas_pause(&xas); | |
1056 | xas_unlock_irq(&xas); | |
1057 | cond_resched(); | |
1058 | xas_lock_irq(&xas); | |
9973c98e | 1059 | } |
9fc747f6 | 1060 | xas_unlock_irq(&xas); |
9fc747f6 MW |
1061 | trace_dax_writeback_range_done(inode, xas.xa_index, end_index); |
1062 | return ret; | |
9973c98e RZ |
1063 | } |
1064 | EXPORT_SYMBOL_GPL(dax_writeback_mapping_range); | |
1065 | ||
e28cd3e5 SR |
1066 | static int dax_iomap_direct_access(const struct iomap *iomap, loff_t pos, |
1067 | size_t size, void **kaddr, pfn_t *pfnp) | |
f7ca90b1 | 1068 | { |
60696eb2 | 1069 | pgoff_t pgoff = dax_iomap_pgoff(iomap, pos); |
e28cd3e5 | 1070 | int id, rc = 0; |
5e161e40 | 1071 | long length; |
f7ca90b1 | 1072 | |
cccbce67 | 1073 | id = dax_read_lock(); |
5e161e40 | 1074 | length = dax_direct_access(iomap->dax_dev, pgoff, PHYS_PFN(size), |
e28cd3e5 | 1075 | DAX_ACCESS, kaddr, pfnp); |
5e161e40 JK |
1076 | if (length < 0) { |
1077 | rc = length; | |
1078 | goto out; | |
cccbce67 | 1079 | } |
e28cd3e5 SR |
1080 | if (!pfnp) |
1081 | goto out_check_addr; | |
5e161e40 JK |
1082 | rc = -EINVAL; |
1083 | if (PFN_PHYS(length) < size) | |
1084 | goto out; | |
1085 | if (pfn_t_to_pfn(*pfnp) & (PHYS_PFN(size)-1)) | |
1086 | goto out; | |
1087 | /* For larger pages we need devmap */ | |
1088 | if (length > 1 && !pfn_t_devmap(*pfnp)) | |
1089 | goto out; | |
1090 | rc = 0; | |
e28cd3e5 SR |
1091 | |
1092 | out_check_addr: | |
1093 | if (!kaddr) | |
1094 | goto out; | |
1095 | if (!*kaddr) | |
1096 | rc = -EFAULT; | |
5e161e40 | 1097 | out: |
cccbce67 | 1098 | dax_read_unlock(id); |
5e161e40 | 1099 | return rc; |
0e3b210c | 1100 | } |
0e3b210c | 1101 | |
ff17b8df | 1102 | /** |
708dfad2 SR |
1103 | * dax_iomap_copy_around - Prepare for an unaligned write to a shared/cow page |
1104 | * by copying the data before and after the range to be written. | |
ff17b8df SR |
1105 | * @pos: address to do copy from. |
1106 | * @length: size of copy operation. | |
1107 | * @align_size: aligned w.r.t align_size (either PMD_SIZE or PAGE_SIZE) | |
1108 | * @srcmap: iomap srcmap | |
1109 | * @daddr: destination address to copy to. | |
1110 | * | |
1111 | * This can be called from two places. Either during DAX write fault (page | |
1112 | * aligned), to copy the length size data to daddr. Or, while doing normal DAX | |
708dfad2 | 1113 | * write operation, dax_iomap_iter() might call this to do the copy of either |
ff17b8df | 1114 | * start or end unaligned address. In the latter case the rest of the copy of |
708dfad2 SR |
1115 | * aligned ranges is taken care by dax_iomap_iter() itself. |
1116 | * If the srcmap contains invalid data, such as HOLE and UNWRITTEN, zero the | |
1117 | * area to make sure no old data remains. | |
ff17b8df | 1118 | */ |
708dfad2 | 1119 | static int dax_iomap_copy_around(loff_t pos, uint64_t length, size_t align_size, |
ff17b8df SR |
1120 | const struct iomap *srcmap, void *daddr) |
1121 | { | |
1122 | loff_t head_off = pos & (align_size - 1); | |
1123 | size_t size = ALIGN(head_off + length, align_size); | |
1124 | loff_t end = pos + length; | |
1125 | loff_t pg_end = round_up(end, align_size); | |
708dfad2 | 1126 | /* copy_all is usually in page fault case */ |
ff17b8df | 1127 | bool copy_all = head_off == 0 && end == pg_end; |
708dfad2 SR |
1128 | /* zero the edges if srcmap is a HOLE or IOMAP_UNWRITTEN */ |
1129 | bool zero_edge = srcmap->flags & IOMAP_F_SHARED || | |
1130 | srcmap->type == IOMAP_UNWRITTEN; | |
ff17b8df SR |
1131 | void *saddr = 0; |
1132 | int ret = 0; | |
1133 | ||
708dfad2 SR |
1134 | if (!zero_edge) { |
1135 | ret = dax_iomap_direct_access(srcmap, pos, size, &saddr, NULL); | |
1136 | if (ret) | |
1ea7ca1b | 1137 | return dax_mem2blk_err(ret); |
708dfad2 | 1138 | } |
ff17b8df SR |
1139 | |
1140 | if (copy_all) { | |
708dfad2 SR |
1141 | if (zero_edge) |
1142 | memset(daddr, 0, size); | |
1143 | else | |
1144 | ret = copy_mc_to_kernel(daddr, saddr, length); | |
1145 | goto out; | |
ff17b8df SR |
1146 | } |
1147 | ||
1148 | /* Copy the head part of the range */ | |
1149 | if (head_off) { | |
708dfad2 SR |
1150 | if (zero_edge) |
1151 | memset(daddr, 0, head_off); | |
1152 | else { | |
1153 | ret = copy_mc_to_kernel(daddr, saddr, head_off); | |
1154 | if (ret) | |
1155 | return -EIO; | |
1156 | } | |
ff17b8df SR |
1157 | } |
1158 | ||
1159 | /* Copy the tail part of the range */ | |
1160 | if (end < pg_end) { | |
1161 | loff_t tail_off = head_off + length; | |
1162 | loff_t tail_len = pg_end - end; | |
1163 | ||
708dfad2 SR |
1164 | if (zero_edge) |
1165 | memset(daddr + tail_off, 0, tail_len); | |
1166 | else { | |
1167 | ret = copy_mc_to_kernel(daddr + tail_off, | |
1168 | saddr + tail_off, tail_len); | |
1169 | if (ret) | |
1170 | return -EIO; | |
1171 | } | |
ff17b8df | 1172 | } |
708dfad2 SR |
1173 | out: |
1174 | if (zero_edge) | |
1175 | dax_flush(srcmap->dax_dev, daddr, size); | |
1176 | return ret ? -EIO : 0; | |
ff17b8df SR |
1177 | } |
1178 | ||
e30331ff | 1179 | /* |
91d25ba8 RZ |
1180 | * The user has performed a load from a hole in the file. Allocating a new |
1181 | * page in the file would cause excessive storage usage for workloads with | |
1182 | * sparse files. Instead we insert a read-only mapping of the 4k zero page. | |
1183 | * If this page is ever written to we will re-fault and change the mapping to | |
1184 | * point to real DAX storage instead. | |
e30331ff | 1185 | */ |
e5d6df73 SR |
1186 | static vm_fault_t dax_load_hole(struct xa_state *xas, struct vm_fault *vmf, |
1187 | const struct iomap_iter *iter, void **entry) | |
e30331ff | 1188 | { |
e5d6df73 | 1189 | struct inode *inode = iter->inode; |
91d25ba8 | 1190 | unsigned long vaddr = vmf->address; |
b90ca5cc MW |
1191 | pfn_t pfn = pfn_to_pfn_t(my_zero_pfn(vaddr)); |
1192 | vm_fault_t ret; | |
e30331ff | 1193 | |
e5d6df73 | 1194 | *entry = dax_insert_entry(xas, vmf, iter, *entry, pfn, DAX_ZERO_PAGE); |
3159f943 | 1195 | |
ab77dab4 | 1196 | ret = vmf_insert_mixed(vmf->vma, vaddr, pfn); |
e30331ff RZ |
1197 | trace_dax_load_hole(inode, vmf, ret); |
1198 | return ret; | |
1199 | } | |
1200 | ||
c2436190 SR |
1201 | #ifdef CONFIG_FS_DAX_PMD |
1202 | static vm_fault_t dax_pmd_load_hole(struct xa_state *xas, struct vm_fault *vmf, | |
e5d6df73 | 1203 | const struct iomap_iter *iter, void **entry) |
c2436190 SR |
1204 | { |
1205 | struct address_space *mapping = vmf->vma->vm_file->f_mapping; | |
1206 | unsigned long pmd_addr = vmf->address & PMD_MASK; | |
1207 | struct vm_area_struct *vma = vmf->vma; | |
1208 | struct inode *inode = mapping->host; | |
1209 | pgtable_t pgtable = NULL; | |
1210 | struct page *zero_page; | |
1211 | spinlock_t *ptl; | |
1212 | pmd_t pmd_entry; | |
1213 | pfn_t pfn; | |
1214 | ||
1215 | zero_page = mm_get_huge_zero_page(vmf->vma->vm_mm); | |
1216 | ||
1217 | if (unlikely(!zero_page)) | |
1218 | goto fallback; | |
1219 | ||
1220 | pfn = page_to_pfn_t(zero_page); | |
e5d6df73 SR |
1221 | *entry = dax_insert_entry(xas, vmf, iter, *entry, pfn, |
1222 | DAX_PMD | DAX_ZERO_PAGE); | |
c2436190 SR |
1223 | |
1224 | if (arch_needs_pgtable_deposit()) { | |
1225 | pgtable = pte_alloc_one(vma->vm_mm); | |
1226 | if (!pgtable) | |
1227 | return VM_FAULT_OOM; | |
1228 | } | |
1229 | ||
1230 | ptl = pmd_lock(vmf->vma->vm_mm, vmf->pmd); | |
1231 | if (!pmd_none(*(vmf->pmd))) { | |
1232 | spin_unlock(ptl); | |
1233 | goto fallback; | |
1234 | } | |
1235 | ||
1236 | if (pgtable) { | |
1237 | pgtable_trans_huge_deposit(vma->vm_mm, vmf->pmd, pgtable); | |
1238 | mm_inc_nr_ptes(vma->vm_mm); | |
1239 | } | |
1240 | pmd_entry = mk_pmd(zero_page, vmf->vma->vm_page_prot); | |
1241 | pmd_entry = pmd_mkhuge(pmd_entry); | |
1242 | set_pmd_at(vmf->vma->vm_mm, pmd_addr, vmf->pmd, pmd_entry); | |
1243 | spin_unlock(ptl); | |
1244 | trace_dax_pmd_load_hole(inode, vmf, zero_page, *entry); | |
1245 | return VM_FAULT_NOPAGE; | |
1246 | ||
1247 | fallback: | |
1248 | if (pgtable) | |
1249 | pte_free(vma->vm_mm, pgtable); | |
1250 | trace_dax_pmd_load_hole_fallback(inode, vmf, zero_page, *entry); | |
1251 | return VM_FAULT_FALLBACK; | |
1252 | } | |
1253 | #else | |
1254 | static vm_fault_t dax_pmd_load_hole(struct xa_state *xas, struct vm_fault *vmf, | |
e5d6df73 | 1255 | const struct iomap_iter *iter, void **entry) |
c2436190 SR |
1256 | { |
1257 | return VM_FAULT_FALLBACK; | |
1258 | } | |
1259 | #endif /* CONFIG_FS_DAX_PMD */ | |
1260 | ||
d984648e SR |
1261 | static s64 dax_unshare_iter(struct iomap_iter *iter) |
1262 | { | |
1263 | struct iomap *iomap = &iter->iomap; | |
1264 | const struct iomap *srcmap = iomap_iter_srcmap(iter); | |
1265 | loff_t pos = iter->pos; | |
1266 | loff_t length = iomap_length(iter); | |
1267 | int id = 0; | |
1268 | s64 ret = 0; | |
1269 | void *daddr = NULL, *saddr = NULL; | |
1270 | ||
1271 | /* don't bother with blocks that are not shared to start with */ | |
1272 | if (!(iomap->flags & IOMAP_F_SHARED)) | |
1273 | return length; | |
d984648e SR |
1274 | |
1275 | id = dax_read_lock(); | |
1276 | ret = dax_iomap_direct_access(iomap, pos, length, &daddr, NULL); | |
1277 | if (ret < 0) | |
1278 | goto out_unlock; | |
1279 | ||
13dd4e04 SR |
1280 | /* zero the distance if srcmap is HOLE or UNWRITTEN */ |
1281 | if (srcmap->flags & IOMAP_F_SHARED || srcmap->type == IOMAP_UNWRITTEN) { | |
1282 | memset(daddr, 0, length); | |
1283 | dax_flush(iomap->dax_dev, daddr, length); | |
1284 | ret = length; | |
1285 | goto out_unlock; | |
1286 | } | |
1287 | ||
d984648e SR |
1288 | ret = dax_iomap_direct_access(srcmap, pos, length, &saddr, NULL); |
1289 | if (ret < 0) | |
1290 | goto out_unlock; | |
1291 | ||
388bc034 SR |
1292 | if (copy_mc_to_kernel(daddr, saddr, length) == 0) |
1293 | ret = length; | |
1294 | else | |
d984648e SR |
1295 | ret = -EIO; |
1296 | ||
1297 | out_unlock: | |
1298 | dax_read_unlock(id); | |
1ea7ca1b | 1299 | return dax_mem2blk_err(ret); |
d984648e SR |
1300 | } |
1301 | ||
1302 | int dax_file_unshare(struct inode *inode, loff_t pos, loff_t len, | |
1303 | const struct iomap_ops *ops) | |
1304 | { | |
1305 | struct iomap_iter iter = { | |
1306 | .inode = inode, | |
1307 | .pos = pos, | |
1308 | .len = len, | |
1309 | .flags = IOMAP_WRITE | IOMAP_UNSHARE | IOMAP_DAX, | |
1310 | }; | |
1311 | int ret; | |
1312 | ||
1313 | while ((ret = iomap_iter(&iter, ops)) > 0) | |
1314 | iter.processed = dax_unshare_iter(&iter); | |
1315 | return ret; | |
1316 | } | |
1317 | EXPORT_SYMBOL_GPL(dax_file_unshare); | |
1318 | ||
8dbfc76d | 1319 | static int dax_memzero(struct iomap_iter *iter, loff_t pos, size_t size) |
e5c71954 | 1320 | { |
8dbfc76d SR |
1321 | const struct iomap *iomap = &iter->iomap; |
1322 | const struct iomap *srcmap = iomap_iter_srcmap(iter); | |
1323 | unsigned offset = offset_in_page(pos); | |
1324 | pgoff_t pgoff = dax_iomap_pgoff(iomap, pos); | |
e5c71954 CH |
1325 | void *kaddr; |
1326 | long ret; | |
1327 | ||
8dbfc76d SR |
1328 | ret = dax_direct_access(iomap->dax_dev, pgoff, 1, DAX_ACCESS, &kaddr, |
1329 | NULL); | |
1330 | if (ret < 0) | |
1ea7ca1b JC |
1331 | return dax_mem2blk_err(ret); |
1332 | ||
8dbfc76d | 1333 | memset(kaddr + offset, 0, size); |
708dfad2 SR |
1334 | if (iomap->flags & IOMAP_F_SHARED) |
1335 | ret = dax_iomap_copy_around(pos, size, PAGE_SIZE, srcmap, | |
1336 | kaddr); | |
1337 | else | |
8dbfc76d | 1338 | dax_flush(iomap->dax_dev, kaddr + offset, size); |
e5c71954 CH |
1339 | return ret; |
1340 | } | |
1341 | ||
c6f40468 | 1342 | static s64 dax_zero_iter(struct iomap_iter *iter, bool *did_zero) |
679c8bd3 | 1343 | { |
c6f40468 CH |
1344 | const struct iomap *iomap = &iter->iomap; |
1345 | const struct iomap *srcmap = iomap_iter_srcmap(iter); | |
1346 | loff_t pos = iter->pos; | |
1347 | u64 length = iomap_length(iter); | |
1348 | s64 written = 0; | |
1349 | ||
1350 | /* already zeroed? we're done. */ | |
1351 | if (srcmap->type == IOMAP_HOLE || srcmap->type == IOMAP_UNWRITTEN) | |
1352 | return length; | |
1353 | ||
f80e1668 SR |
1354 | /* |
1355 | * invalidate the pages whose sharing state is to be changed | |
1356 | * because of CoW. | |
1357 | */ | |
1358 | if (iomap->flags & IOMAP_F_SHARED) | |
1359 | invalidate_inode_pages2_range(iter->inode->i_mapping, | |
1360 | pos >> PAGE_SHIFT, | |
1361 | (pos + length - 1) >> PAGE_SHIFT); | |
1362 | ||
c6f40468 CH |
1363 | do { |
1364 | unsigned offset = offset_in_page(pos); | |
1365 | unsigned size = min_t(u64, PAGE_SIZE - offset, length); | |
1366 | pgoff_t pgoff = dax_iomap_pgoff(iomap, pos); | |
1367 | long rc; | |
1368 | int id; | |
1369 | ||
1370 | id = dax_read_lock(); | |
1371 | if (IS_ALIGNED(pos, PAGE_SIZE) && size == PAGE_SIZE) | |
1372 | rc = dax_zero_page_range(iomap->dax_dev, pgoff, 1); | |
1373 | else | |
8dbfc76d | 1374 | rc = dax_memzero(iter, pos, size); |
c6f40468 | 1375 | dax_read_unlock(id); |
cccbce67 | 1376 | |
c6f40468 CH |
1377 | if (rc < 0) |
1378 | return rc; | |
1379 | pos += size; | |
1380 | length -= size; | |
1381 | written += size; | |
c6f40468 | 1382 | } while (length > 0); |
e5c71954 | 1383 | |
f8189d5d KX |
1384 | if (did_zero) |
1385 | *did_zero = true; | |
c6f40468 CH |
1386 | return written; |
1387 | } | |
1388 | ||
1389 | int dax_zero_range(struct inode *inode, loff_t pos, loff_t len, bool *did_zero, | |
1390 | const struct iomap_ops *ops) | |
1391 | { | |
1392 | struct iomap_iter iter = { | |
1393 | .inode = inode, | |
1394 | .pos = pos, | |
1395 | .len = len, | |
952da063 | 1396 | .flags = IOMAP_DAX | IOMAP_ZERO, |
c6f40468 CH |
1397 | }; |
1398 | int ret; | |
1399 | ||
1400 | while ((ret = iomap_iter(&iter, ops)) > 0) | |
1401 | iter.processed = dax_zero_iter(&iter, did_zero); | |
1402 | return ret; | |
1403 | } | |
1404 | EXPORT_SYMBOL_GPL(dax_zero_range); | |
1405 | ||
1406 | int dax_truncate_page(struct inode *inode, loff_t pos, bool *did_zero, | |
1407 | const struct iomap_ops *ops) | |
1408 | { | |
1409 | unsigned int blocksize = i_blocksize(inode); | |
1410 | unsigned int off = pos & (blocksize - 1); | |
1411 | ||
1412 | /* Block boundary? Nothing to do */ | |
1413 | if (!off) | |
1414 | return 0; | |
1415 | return dax_zero_range(inode, pos, blocksize - off, did_zero, ops); | |
679c8bd3 | 1416 | } |
c6f40468 | 1417 | EXPORT_SYMBOL_GPL(dax_truncate_page); |
679c8bd3 | 1418 | |
ca289e0b CH |
1419 | static loff_t dax_iomap_iter(const struct iomap_iter *iomi, |
1420 | struct iov_iter *iter) | |
a254e568 | 1421 | { |
ca289e0b | 1422 | const struct iomap *iomap = &iomi->iomap; |
f80e1668 | 1423 | const struct iomap *srcmap = iomap_iter_srcmap(iomi); |
ca289e0b CH |
1424 | loff_t length = iomap_length(iomi); |
1425 | loff_t pos = iomi->pos; | |
cccbce67 | 1426 | struct dax_device *dax_dev = iomap->dax_dev; |
a254e568 | 1427 | loff_t end = pos + length, done = 0; |
ff17b8df | 1428 | bool write = iov_iter_rw(iter) == WRITE; |
f80e1668 | 1429 | bool cow = write && iomap->flags & IOMAP_F_SHARED; |
a254e568 | 1430 | ssize_t ret = 0; |
a77d4786 | 1431 | size_t xfer; |
cccbce67 | 1432 | int id; |
a254e568 | 1433 | |
ff17b8df | 1434 | if (!write) { |
ca289e0b | 1435 | end = min(end, i_size_read(iomi->inode)); |
a254e568 CH |
1436 | if (pos >= end) |
1437 | return 0; | |
1438 | ||
1439 | if (iomap->type == IOMAP_HOLE || iomap->type == IOMAP_UNWRITTEN) | |
1440 | return iov_iter_zero(min(length, end - pos), iter); | |
1441 | } | |
1442 | ||
ff17b8df SR |
1443 | /* |
1444 | * In DAX mode, enforce either pure overwrites of written extents, or | |
1445 | * writes to unwritten extents as part of a copy-on-write operation. | |
1446 | */ | |
1447 | if (WARN_ON_ONCE(iomap->type != IOMAP_MAPPED && | |
1448 | !(iomap->flags & IOMAP_F_SHARED))) | |
a254e568 CH |
1449 | return -EIO; |
1450 | ||
e3fce68c JK |
1451 | /* |
1452 | * Write can allocate block for an area which has a hole page mapped | |
1453 | * into page tables. We have to tear down these mappings so that data | |
1454 | * written by write(2) is visible in mmap. | |
1455 | */ | |
f80e1668 | 1456 | if (iomap->flags & IOMAP_F_NEW || cow) { |
f76b3a32 SR |
1457 | /* |
1458 | * Filesystem allows CoW on non-shared extents. The src extents | |
1459 | * may have been mmapped with dirty mark before. To be able to | |
1460 | * invalidate its dax entries, we need to clear the dirty mark | |
1461 | * in advance. | |
1462 | */ | |
1463 | if (cow) | |
1464 | __dax_clear_dirty_range(iomi->inode->i_mapping, | |
1465 | pos >> PAGE_SHIFT, | |
1466 | (end - 1) >> PAGE_SHIFT); | |
ca289e0b | 1467 | invalidate_inode_pages2_range(iomi->inode->i_mapping, |
e3fce68c JK |
1468 | pos >> PAGE_SHIFT, |
1469 | (end - 1) >> PAGE_SHIFT); | |
1470 | } | |
1471 | ||
cccbce67 | 1472 | id = dax_read_lock(); |
a254e568 CH |
1473 | while (pos < end) { |
1474 | unsigned offset = pos & (PAGE_SIZE - 1); | |
cccbce67 | 1475 | const size_t size = ALIGN(length + offset, PAGE_SIZE); |
60696eb2 | 1476 | pgoff_t pgoff = dax_iomap_pgoff(iomap, pos); |
a254e568 | 1477 | ssize_t map_len; |
047218ec | 1478 | bool recovery = false; |
cccbce67 | 1479 | void *kaddr; |
a254e568 | 1480 | |
d1908f52 MH |
1481 | if (fatal_signal_pending(current)) { |
1482 | ret = -EINTR; | |
1483 | break; | |
1484 | } | |
1485 | ||
cccbce67 | 1486 | map_len = dax_direct_access(dax_dev, pgoff, PHYS_PFN(size), |
e511c4a3 | 1487 | DAX_ACCESS, &kaddr, NULL); |
1ea7ca1b | 1488 | if (map_len == -EHWPOISON && iov_iter_rw(iter) == WRITE) { |
047218ec JC |
1489 | map_len = dax_direct_access(dax_dev, pgoff, |
1490 | PHYS_PFN(size), DAX_RECOVERY_WRITE, | |
1491 | &kaddr, NULL); | |
1492 | if (map_len > 0) | |
1493 | recovery = true; | |
1494 | } | |
a254e568 | 1495 | if (map_len < 0) { |
1ea7ca1b | 1496 | ret = dax_mem2blk_err(map_len); |
a254e568 CH |
1497 | break; |
1498 | } | |
1499 | ||
f80e1668 | 1500 | if (cow) { |
708dfad2 SR |
1501 | ret = dax_iomap_copy_around(pos, length, PAGE_SIZE, |
1502 | srcmap, kaddr); | |
ff17b8df SR |
1503 | if (ret) |
1504 | break; | |
1505 | } | |
1506 | ||
cccbce67 DW |
1507 | map_len = PFN_PHYS(map_len); |
1508 | kaddr += offset; | |
a254e568 CH |
1509 | map_len -= offset; |
1510 | if (map_len > end - pos) | |
1511 | map_len = end - pos; | |
1512 | ||
047218ec JC |
1513 | if (recovery) |
1514 | xfer = dax_recovery_write(dax_dev, pgoff, kaddr, | |
1515 | map_len, iter); | |
ff17b8df | 1516 | else if (write) |
a77d4786 | 1517 | xfer = dax_copy_from_iter(dax_dev, pgoff, kaddr, |
fec53774 | 1518 | map_len, iter); |
a254e568 | 1519 | else |
a77d4786 | 1520 | xfer = dax_copy_to_iter(dax_dev, pgoff, kaddr, |
b3a9a0c3 | 1521 | map_len, iter); |
a254e568 | 1522 | |
a77d4786 DW |
1523 | pos += xfer; |
1524 | length -= xfer; | |
1525 | done += xfer; | |
1526 | ||
1527 | if (xfer == 0) | |
1528 | ret = -EFAULT; | |
1529 | if (xfer < map_len) | |
1530 | break; | |
a254e568 | 1531 | } |
cccbce67 | 1532 | dax_read_unlock(id); |
a254e568 CH |
1533 | |
1534 | return done ? done : ret; | |
1535 | } | |
1536 | ||
1537 | /** | |
11c59c92 | 1538 | * dax_iomap_rw - Perform I/O to a DAX file |
a254e568 CH |
1539 | * @iocb: The control block for this I/O |
1540 | * @iter: The addresses to do I/O from or to | |
1541 | * @ops: iomap ops passed from the file system | |
1542 | * | |
1543 | * This function performs read and write operations to directly mapped | |
1544 | * persistent memory. The callers needs to take care of read/write exclusion | |
1545 | * and evicting any page cache pages in the region under I/O. | |
1546 | */ | |
1547 | ssize_t | |
11c59c92 | 1548 | dax_iomap_rw(struct kiocb *iocb, struct iov_iter *iter, |
8ff6daa1 | 1549 | const struct iomap_ops *ops) |
a254e568 | 1550 | { |
ca289e0b CH |
1551 | struct iomap_iter iomi = { |
1552 | .inode = iocb->ki_filp->f_mapping->host, | |
1553 | .pos = iocb->ki_pos, | |
1554 | .len = iov_iter_count(iter), | |
952da063 | 1555 | .flags = IOMAP_DAX, |
ca289e0b CH |
1556 | }; |
1557 | loff_t done = 0; | |
1558 | int ret; | |
a254e568 | 1559 | |
17d9c15c LJ |
1560 | if (!iomi.len) |
1561 | return 0; | |
1562 | ||
168316db | 1563 | if (iov_iter_rw(iter) == WRITE) { |
ca289e0b CH |
1564 | lockdep_assert_held_write(&iomi.inode->i_rwsem); |
1565 | iomi.flags |= IOMAP_WRITE; | |
168316db | 1566 | } else { |
ca289e0b | 1567 | lockdep_assert_held(&iomi.inode->i_rwsem); |
168316db | 1568 | } |
a254e568 | 1569 | |
96222d53 | 1570 | if (iocb->ki_flags & IOCB_NOWAIT) |
ca289e0b | 1571 | iomi.flags |= IOMAP_NOWAIT; |
96222d53 | 1572 | |
ca289e0b CH |
1573 | while ((ret = iomap_iter(&iomi, ops)) > 0) |
1574 | iomi.processed = dax_iomap_iter(&iomi, iter); | |
a254e568 | 1575 | |
ca289e0b CH |
1576 | done = iomi.pos - iocb->ki_pos; |
1577 | iocb->ki_pos = iomi.pos; | |
a254e568 CH |
1578 | return done ? done : ret; |
1579 | } | |
11c59c92 | 1580 | EXPORT_SYMBOL_GPL(dax_iomap_rw); |
a7d73fe6 | 1581 | |
ab77dab4 | 1582 | static vm_fault_t dax_fault_return(int error) |
9f141d6e JK |
1583 | { |
1584 | if (error == 0) | |
1585 | return VM_FAULT_NOPAGE; | |
c9aed74e | 1586 | return vmf_error(error); |
9f141d6e JK |
1587 | } |
1588 | ||
55f81639 SR |
1589 | /* |
1590 | * When handling a synchronous page fault and the inode need a fsync, we can | |
1591 | * insert the PTE/PMD into page tables only after that fsync happened. Skip | |
1592 | * insertion for now and return the pfn so that caller can insert it after the | |
1593 | * fsync is done. | |
1594 | */ | |
1595 | static vm_fault_t dax_fault_synchronous_pfnp(pfn_t *pfnp, pfn_t pfn) | |
1596 | { | |
1597 | if (WARN_ON_ONCE(!pfnp)) | |
1598 | return VM_FAULT_SIGBUS; | |
1599 | *pfnp = pfn; | |
1600 | return VM_FAULT_NEEDDSYNC; | |
1601 | } | |
1602 | ||
65dd814a CH |
1603 | static vm_fault_t dax_fault_cow_page(struct vm_fault *vmf, |
1604 | const struct iomap_iter *iter) | |
55f81639 | 1605 | { |
55f81639 SR |
1606 | vm_fault_t ret; |
1607 | int error = 0; | |
1608 | ||
65dd814a | 1609 | switch (iter->iomap.type) { |
55f81639 SR |
1610 | case IOMAP_HOLE: |
1611 | case IOMAP_UNWRITTEN: | |
429f8de7 | 1612 | clear_user_highpage(vmf->cow_page, vmf->address); |
55f81639 SR |
1613 | break; |
1614 | case IOMAP_MAPPED: | |
429f8de7 | 1615 | error = copy_cow_page_dax(vmf, iter); |
55f81639 SR |
1616 | break; |
1617 | default: | |
1618 | WARN_ON_ONCE(1); | |
1619 | error = -EIO; | |
1620 | break; | |
1621 | } | |
1622 | ||
1623 | if (error) | |
1624 | return dax_fault_return(error); | |
1625 | ||
1626 | __SetPageUptodate(vmf->cow_page); | |
1627 | ret = finish_fault(vmf); | |
1628 | if (!ret) | |
1629 | return VM_FAULT_DONE_COW; | |
1630 | return ret; | |
1631 | } | |
1632 | ||
c2436190 | 1633 | /** |
65dd814a | 1634 | * dax_fault_iter - Common actor to handle pfn insertion in PTE/PMD fault. |
c2436190 | 1635 | * @vmf: vm fault instance |
65dd814a | 1636 | * @iter: iomap iter |
c2436190 SR |
1637 | * @pfnp: pfn to be returned |
1638 | * @xas: the dax mapping tree of a file | |
1639 | * @entry: an unlocked dax entry to be inserted | |
1640 | * @pmd: distinguish whether it is a pmd fault | |
c2436190 | 1641 | */ |
65dd814a CH |
1642 | static vm_fault_t dax_fault_iter(struct vm_fault *vmf, |
1643 | const struct iomap_iter *iter, pfn_t *pfnp, | |
1644 | struct xa_state *xas, void **entry, bool pmd) | |
c2436190 | 1645 | { |
65dd814a | 1646 | const struct iomap *iomap = &iter->iomap; |
708dfad2 | 1647 | const struct iomap *srcmap = iomap_iter_srcmap(iter); |
c2436190 SR |
1648 | size_t size = pmd ? PMD_SIZE : PAGE_SIZE; |
1649 | loff_t pos = (loff_t)xas->xa_index << PAGE_SHIFT; | |
e5d6df73 | 1650 | bool write = iter->flags & IOMAP_WRITE; |
c2436190 SR |
1651 | unsigned long entry_flags = pmd ? DAX_PMD : 0; |
1652 | int err = 0; | |
1653 | pfn_t pfn; | |
ff17b8df | 1654 | void *kaddr; |
c2436190 | 1655 | |
65dd814a CH |
1656 | if (!pmd && vmf->cow_page) |
1657 | return dax_fault_cow_page(vmf, iter); | |
1658 | ||
c2436190 SR |
1659 | /* if we are reading UNWRITTEN and HOLE, return a hole. */ |
1660 | if (!write && | |
1661 | (iomap->type == IOMAP_UNWRITTEN || iomap->type == IOMAP_HOLE)) { | |
1662 | if (!pmd) | |
e5d6df73 SR |
1663 | return dax_load_hole(xas, vmf, iter, entry); |
1664 | return dax_pmd_load_hole(xas, vmf, iter, entry); | |
c2436190 SR |
1665 | } |
1666 | ||
ff17b8df | 1667 | if (iomap->type != IOMAP_MAPPED && !(iomap->flags & IOMAP_F_SHARED)) { |
c2436190 SR |
1668 | WARN_ON_ONCE(1); |
1669 | return pmd ? VM_FAULT_FALLBACK : VM_FAULT_SIGBUS; | |
1670 | } | |
1671 | ||
ff17b8df | 1672 | err = dax_iomap_direct_access(iomap, pos, size, &kaddr, &pfn); |
c2436190 SR |
1673 | if (err) |
1674 | return pmd ? VM_FAULT_FALLBACK : dax_fault_return(err); | |
1675 | ||
e5d6df73 | 1676 | *entry = dax_insert_entry(xas, vmf, iter, *entry, pfn, entry_flags); |
c2436190 | 1677 | |
708dfad2 SR |
1678 | if (write && iomap->flags & IOMAP_F_SHARED) { |
1679 | err = dax_iomap_copy_around(pos, size, size, srcmap, kaddr); | |
ff17b8df SR |
1680 | if (err) |
1681 | return dax_fault_return(err); | |
1682 | } | |
c2436190 | 1683 | |
e5d6df73 | 1684 | if (dax_fault_is_synchronous(iter, vmf->vma)) |
c2436190 SR |
1685 | return dax_fault_synchronous_pfnp(pfnp, pfn); |
1686 | ||
1687 | /* insert PMD pfn */ | |
1688 | if (pmd) | |
1689 | return vmf_insert_pfn_pmd(vmf, pfn, write); | |
1690 | ||
1691 | /* insert PTE pfn */ | |
1692 | if (write) | |
1693 | return vmf_insert_mixed_mkwrite(vmf->vma, vmf->address, pfn); | |
1694 | return vmf_insert_mixed(vmf->vma, vmf->address, pfn); | |
1695 | } | |
1696 | ||
ab77dab4 | 1697 | static vm_fault_t dax_iomap_pte_fault(struct vm_fault *vmf, pfn_t *pfnp, |
c0b24625 | 1698 | int *iomap_errp, const struct iomap_ops *ops) |
a7d73fe6 | 1699 | { |
65dd814a | 1700 | struct address_space *mapping = vmf->vma->vm_file->f_mapping; |
b15cd800 | 1701 | XA_STATE(xas, &mapping->i_pages, vmf->pgoff); |
65dd814a CH |
1702 | struct iomap_iter iter = { |
1703 | .inode = mapping->host, | |
1704 | .pos = (loff_t)vmf->pgoff << PAGE_SHIFT, | |
1705 | .len = PAGE_SIZE, | |
952da063 | 1706 | .flags = IOMAP_DAX | IOMAP_FAULT, |
65dd814a | 1707 | }; |
ab77dab4 | 1708 | vm_fault_t ret = 0; |
a7d73fe6 | 1709 | void *entry; |
65dd814a | 1710 | int error; |
a7d73fe6 | 1711 | |
65dd814a | 1712 | trace_dax_pte_fault(iter.inode, vmf, ret); |
a7d73fe6 CH |
1713 | /* |
1714 | * Check whether offset isn't beyond end of file now. Caller is supposed | |
1715 | * to hold locks serializing us with truncate / punch hole so this is | |
1716 | * a reliable test. | |
1717 | */ | |
65dd814a | 1718 | if (iter.pos >= i_size_read(iter.inode)) { |
ab77dab4 | 1719 | ret = VM_FAULT_SIGBUS; |
a9c42b33 RZ |
1720 | goto out; |
1721 | } | |
a7d73fe6 | 1722 | |
65dd814a CH |
1723 | if ((vmf->flags & FAULT_FLAG_WRITE) && !vmf->cow_page) |
1724 | iter.flags |= IOMAP_WRITE; | |
a7d73fe6 | 1725 | |
b15cd800 MW |
1726 | entry = grab_mapping_entry(&xas, mapping, 0); |
1727 | if (xa_is_internal(entry)) { | |
1728 | ret = xa_to_internal(entry); | |
13e451fd JK |
1729 | goto out; |
1730 | } | |
1731 | ||
e2093926 RZ |
1732 | /* |
1733 | * It is possible, particularly with mixed reads & writes to private | |
1734 | * mappings, that we have raced with a PMD fault that overlaps with | |
1735 | * the PTE we need to set up. If so just return and the fault will be | |
1736 | * retried. | |
1737 | */ | |
1738 | if (pmd_trans_huge(*vmf->pmd) || pmd_devmap(*vmf->pmd)) { | |
ab77dab4 | 1739 | ret = VM_FAULT_NOPAGE; |
e2093926 RZ |
1740 | goto unlock_entry; |
1741 | } | |
1742 | ||
65dd814a CH |
1743 | while ((error = iomap_iter(&iter, ops)) > 0) { |
1744 | if (WARN_ON_ONCE(iomap_length(&iter) < PAGE_SIZE)) { | |
1745 | iter.processed = -EIO; /* fs corruption? */ | |
1746 | continue; | |
a7d73fe6 CH |
1747 | } |
1748 | ||
65dd814a CH |
1749 | ret = dax_fault_iter(vmf, &iter, pfnp, &xas, &entry, false); |
1750 | if (ret != VM_FAULT_SIGBUS && | |
1751 | (iter.iomap.flags & IOMAP_F_NEW)) { | |
a7d73fe6 | 1752 | count_vm_event(PGMAJFAULT); |
65dd814a CH |
1753 | count_memcg_event_mm(vmf->vma->vm_mm, PGMAJFAULT); |
1754 | ret |= VM_FAULT_MAJOR; | |
a7d73fe6 | 1755 | } |
1b5a1cb2 | 1756 | |
65dd814a CH |
1757 | if (!(ret & VM_FAULT_ERROR)) |
1758 | iter.processed = PAGE_SIZE; | |
a7d73fe6 CH |
1759 | } |
1760 | ||
65dd814a CH |
1761 | if (iomap_errp) |
1762 | *iomap_errp = error; | |
1763 | if (!ret && error) | |
1764 | ret = dax_fault_return(error); | |
9f141d6e | 1765 | |
c2436190 | 1766 | unlock_entry: |
b15cd800 | 1767 | dax_unlock_entry(&xas, entry); |
c2436190 | 1768 | out: |
65dd814a CH |
1769 | trace_dax_pte_fault_done(iter.inode, vmf, ret); |
1770 | return ret; | |
a7d73fe6 | 1771 | } |
642261ac RZ |
1772 | |
1773 | #ifdef CONFIG_FS_DAX_PMD | |
55f81639 SR |
1774 | static bool dax_fault_check_fallback(struct vm_fault *vmf, struct xa_state *xas, |
1775 | pgoff_t max_pgoff) | |
642261ac | 1776 | { |
f4200391 | 1777 | unsigned long pmd_addr = vmf->address & PMD_MASK; |
55f81639 | 1778 | bool write = vmf->flags & FAULT_FLAG_WRITE; |
642261ac | 1779 | |
55f81639 SR |
1780 | /* |
1781 | * Make sure that the faulting address's PMD offset (color) matches | |
1782 | * the PMD offset from the start of the file. This is necessary so | |
1783 | * that a PMD range in the page table overlaps exactly with a PMD | |
1784 | * range in the page cache. | |
1785 | */ | |
1786 | if ((vmf->pgoff & PG_PMD_COLOUR) != | |
1787 | ((vmf->address >> PAGE_SHIFT) & PG_PMD_COLOUR)) | |
1788 | return true; | |
642261ac | 1789 | |
55f81639 SR |
1790 | /* Fall back to PTEs if we're going to COW */ |
1791 | if (write && !(vmf->vma->vm_flags & VM_SHARED)) | |
1792 | return true; | |
11cf9d86 | 1793 | |
55f81639 SR |
1794 | /* If the PMD would extend outside the VMA */ |
1795 | if (pmd_addr < vmf->vma->vm_start) | |
1796 | return true; | |
1797 | if ((pmd_addr + PMD_SIZE) > vmf->vma->vm_end) | |
1798 | return true; | |
642261ac | 1799 | |
55f81639 SR |
1800 | /* If the PMD would extend beyond the file size */ |
1801 | if ((xas->xa_index | PG_PMD_COLOUR) >= max_pgoff) | |
1802 | return true; | |
653b2ea3 | 1803 | |
55f81639 | 1804 | return false; |
642261ac RZ |
1805 | } |
1806 | ||
ab77dab4 | 1807 | static vm_fault_t dax_iomap_pmd_fault(struct vm_fault *vmf, pfn_t *pfnp, |
a2d58167 | 1808 | const struct iomap_ops *ops) |
642261ac | 1809 | { |
65dd814a | 1810 | struct address_space *mapping = vmf->vma->vm_file->f_mapping; |
b15cd800 | 1811 | XA_STATE_ORDER(xas, &mapping->i_pages, vmf->pgoff, PMD_ORDER); |
65dd814a CH |
1812 | struct iomap_iter iter = { |
1813 | .inode = mapping->host, | |
1814 | .len = PMD_SIZE, | |
952da063 | 1815 | .flags = IOMAP_DAX | IOMAP_FAULT, |
65dd814a | 1816 | }; |
c2436190 | 1817 | vm_fault_t ret = VM_FAULT_FALLBACK; |
b15cd800 | 1818 | pgoff_t max_pgoff; |
642261ac | 1819 | void *entry; |
642261ac | 1820 | |
65dd814a CH |
1821 | if (vmf->flags & FAULT_FLAG_WRITE) |
1822 | iter.flags |= IOMAP_WRITE; | |
642261ac | 1823 | |
282a8e03 RZ |
1824 | /* |
1825 | * Check whether offset isn't beyond end of file now. Caller is | |
1826 | * supposed to hold locks serializing us with truncate / punch hole so | |
1827 | * this is a reliable test. | |
1828 | */ | |
65dd814a | 1829 | max_pgoff = DIV_ROUND_UP(i_size_read(iter.inode), PAGE_SIZE); |
fffa281b | 1830 | |
65dd814a | 1831 | trace_dax_pmd_fault(iter.inode, vmf, max_pgoff, 0); |
642261ac | 1832 | |
b15cd800 | 1833 | if (xas.xa_index >= max_pgoff) { |
c2436190 | 1834 | ret = VM_FAULT_SIGBUS; |
282a8e03 RZ |
1835 | goto out; |
1836 | } | |
642261ac | 1837 | |
55f81639 | 1838 | if (dax_fault_check_fallback(vmf, &xas, max_pgoff)) |
642261ac RZ |
1839 | goto fallback; |
1840 | ||
876f2946 | 1841 | /* |
b15cd800 MW |
1842 | * grab_mapping_entry() will make sure we get an empty PMD entry, |
1843 | * a zero PMD entry or a DAX PMD. If it can't (because a PTE | |
1844 | * entry is already in the array, for instance), it will return | |
1845 | * VM_FAULT_FALLBACK. | |
876f2946 | 1846 | */ |
23c84eb7 | 1847 | entry = grab_mapping_entry(&xas, mapping, PMD_ORDER); |
b15cd800 | 1848 | if (xa_is_internal(entry)) { |
c2436190 | 1849 | ret = xa_to_internal(entry); |
876f2946 | 1850 | goto fallback; |
b15cd800 | 1851 | } |
876f2946 | 1852 | |
e2093926 RZ |
1853 | /* |
1854 | * It is possible, particularly with mixed reads & writes to private | |
1855 | * mappings, that we have raced with a PTE fault that overlaps with | |
1856 | * the PMD we need to set up. If so just return and the fault will be | |
1857 | * retried. | |
1858 | */ | |
1859 | if (!pmd_none(*vmf->pmd) && !pmd_trans_huge(*vmf->pmd) && | |
1860 | !pmd_devmap(*vmf->pmd)) { | |
c2436190 | 1861 | ret = 0; |
e2093926 RZ |
1862 | goto unlock_entry; |
1863 | } | |
1864 | ||
65dd814a | 1865 | iter.pos = (loff_t)xas.xa_index << PAGE_SHIFT; |
dd0c6425 | 1866 | while (iomap_iter(&iter, ops) > 0) { |
65dd814a CH |
1867 | if (iomap_length(&iter) < PMD_SIZE) |
1868 | continue; /* actually breaks out of the loop */ | |
caa51d26 | 1869 | |
65dd814a CH |
1870 | ret = dax_fault_iter(vmf, &iter, pfnp, &xas, &entry, true); |
1871 | if (ret != VM_FAULT_FALLBACK) | |
1872 | iter.processed = PMD_SIZE; | |
642261ac RZ |
1873 | } |
1874 | ||
c2436190 | 1875 | unlock_entry: |
b15cd800 | 1876 | dax_unlock_entry(&xas, entry); |
c2436190 SR |
1877 | fallback: |
1878 | if (ret == VM_FAULT_FALLBACK) { | |
65dd814a | 1879 | split_huge_pmd(vmf->vma, vmf->pmd, vmf->address); |
642261ac RZ |
1880 | count_vm_event(THP_FAULT_FALLBACK); |
1881 | } | |
282a8e03 | 1882 | out: |
65dd814a | 1883 | trace_dax_pmd_fault_done(iter.inode, vmf, max_pgoff, ret); |
c2436190 | 1884 | return ret; |
642261ac | 1885 | } |
a2d58167 | 1886 | #else |
ab77dab4 | 1887 | static vm_fault_t dax_iomap_pmd_fault(struct vm_fault *vmf, pfn_t *pfnp, |
01cddfe9 | 1888 | const struct iomap_ops *ops) |
a2d58167 DJ |
1889 | { |
1890 | return VM_FAULT_FALLBACK; | |
1891 | } | |
642261ac | 1892 | #endif /* CONFIG_FS_DAX_PMD */ |
a2d58167 DJ |
1893 | |
1894 | /** | |
1895 | * dax_iomap_fault - handle a page fault on a DAX file | |
1896 | * @vmf: The description of the fault | |
1d024e7a | 1897 | * @order: Order of the page to fault in |
9a0dd422 | 1898 | * @pfnp: PFN to insert for synchronous faults if fsync is required |
c0b24625 | 1899 | * @iomap_errp: Storage for detailed error code in case of error |
cec04e8c | 1900 | * @ops: Iomap ops passed from the file system |
a2d58167 DJ |
1901 | * |
1902 | * When a page fault occurs, filesystems may call this helper in | |
1903 | * their fault handler for DAX files. dax_iomap_fault() assumes the caller | |
1904 | * has done all the necessary locking for page fault to proceed | |
1905 | * successfully. | |
1906 | */ | |
1d024e7a | 1907 | vm_fault_t dax_iomap_fault(struct vm_fault *vmf, unsigned int order, |
c0b24625 | 1908 | pfn_t *pfnp, int *iomap_errp, const struct iomap_ops *ops) |
a2d58167 | 1909 | { |
1d024e7a | 1910 | if (order == 0) |
c0b24625 | 1911 | return dax_iomap_pte_fault(vmf, pfnp, iomap_errp, ops); |
1d024e7a | 1912 | else if (order == PMD_ORDER) |
9a0dd422 | 1913 | return dax_iomap_pmd_fault(vmf, pfnp, ops); |
1d024e7a | 1914 | else |
a2d58167 | 1915 | return VM_FAULT_FALLBACK; |
a2d58167 DJ |
1916 | } |
1917 | EXPORT_SYMBOL_GPL(dax_iomap_fault); | |
71eab6df | 1918 | |
a77d19f4 | 1919 | /* |
71eab6df JK |
1920 | * dax_insert_pfn_mkwrite - insert PTE or PMD entry into page tables |
1921 | * @vmf: The description of the fault | |
71eab6df | 1922 | * @pfn: PFN to insert |
cfc93c6c | 1923 | * @order: Order of entry to insert. |
71eab6df | 1924 | * |
a77d19f4 MW |
1925 | * This function inserts a writeable PTE or PMD entry into the page tables |
1926 | * for an mmaped DAX file. It also marks the page cache entry as dirty. | |
71eab6df | 1927 | */ |
cfc93c6c MW |
1928 | static vm_fault_t |
1929 | dax_insert_pfn_mkwrite(struct vm_fault *vmf, pfn_t pfn, unsigned int order) | |
71eab6df JK |
1930 | { |
1931 | struct address_space *mapping = vmf->vma->vm_file->f_mapping; | |
cfc93c6c MW |
1932 | XA_STATE_ORDER(xas, &mapping->i_pages, vmf->pgoff, order); |
1933 | void *entry; | |
ab77dab4 | 1934 | vm_fault_t ret; |
71eab6df | 1935 | |
cfc93c6c | 1936 | xas_lock_irq(&xas); |
23c84eb7 | 1937 | entry = get_unlocked_entry(&xas, order); |
71eab6df | 1938 | /* Did we race with someone splitting entry or so? */ |
23c84eb7 MWO |
1939 | if (!entry || dax_is_conflict(entry) || |
1940 | (order == 0 && !dax_is_pte_entry(entry))) { | |
4c3d043d | 1941 | put_unlocked_entry(&xas, entry, WAKE_NEXT); |
cfc93c6c | 1942 | xas_unlock_irq(&xas); |
71eab6df JK |
1943 | trace_dax_insert_pfn_mkwrite_no_entry(mapping->host, vmf, |
1944 | VM_FAULT_NOPAGE); | |
1945 | return VM_FAULT_NOPAGE; | |
1946 | } | |
cfc93c6c MW |
1947 | xas_set_mark(&xas, PAGECACHE_TAG_DIRTY); |
1948 | dax_lock_entry(&xas, entry); | |
1949 | xas_unlock_irq(&xas); | |
1950 | if (order == 0) | |
ab77dab4 | 1951 | ret = vmf_insert_mixed_mkwrite(vmf->vma, vmf->address, pfn); |
71eab6df | 1952 | #ifdef CONFIG_FS_DAX_PMD |
cfc93c6c | 1953 | else if (order == PMD_ORDER) |
fce86ff5 | 1954 | ret = vmf_insert_pfn_pmd(vmf, pfn, FAULT_FLAG_WRITE); |
71eab6df | 1955 | #endif |
cfc93c6c | 1956 | else |
ab77dab4 | 1957 | ret = VM_FAULT_FALLBACK; |
cfc93c6c | 1958 | dax_unlock_entry(&xas, entry); |
ab77dab4 SJ |
1959 | trace_dax_insert_pfn_mkwrite(mapping->host, vmf, ret); |
1960 | return ret; | |
71eab6df JK |
1961 | } |
1962 | ||
1963 | /** | |
1964 | * dax_finish_sync_fault - finish synchronous page fault | |
1965 | * @vmf: The description of the fault | |
1d024e7a | 1966 | * @order: Order of entry to be inserted |
71eab6df JK |
1967 | * @pfn: PFN to insert |
1968 | * | |
1969 | * This function ensures that the file range touched by the page fault is | |
1970 | * stored persistently on the media and handles inserting of appropriate page | |
1971 | * table entry. | |
1972 | */ | |
1d024e7a MWO |
1973 | vm_fault_t dax_finish_sync_fault(struct vm_fault *vmf, unsigned int order, |
1974 | pfn_t pfn) | |
71eab6df JK |
1975 | { |
1976 | int err; | |
1977 | loff_t start = ((loff_t)vmf->pgoff) << PAGE_SHIFT; | |
cfc93c6c | 1978 | size_t len = PAGE_SIZE << order; |
71eab6df | 1979 | |
71eab6df JK |
1980 | err = vfs_fsync_range(vmf->vma->vm_file, start, start + len - 1, 1); |
1981 | if (err) | |
1982 | return VM_FAULT_SIGBUS; | |
cfc93c6c | 1983 | return dax_insert_pfn_mkwrite(vmf, pfn, order); |
71eab6df JK |
1984 | } |
1985 | EXPORT_SYMBOL_GPL(dax_finish_sync_fault); | |
6f7db389 SR |
1986 | |
1987 | static loff_t dax_range_compare_iter(struct iomap_iter *it_src, | |
1988 | struct iomap_iter *it_dest, u64 len, bool *same) | |
1989 | { | |
1990 | const struct iomap *smap = &it_src->iomap; | |
1991 | const struct iomap *dmap = &it_dest->iomap; | |
1992 | loff_t pos1 = it_src->pos, pos2 = it_dest->pos; | |
1993 | void *saddr, *daddr; | |
1994 | int id, ret; | |
1995 | ||
1996 | len = min(len, min(smap->length, dmap->length)); | |
1997 | ||
1998 | if (smap->type == IOMAP_HOLE && dmap->type == IOMAP_HOLE) { | |
1999 | *same = true; | |
2000 | return len; | |
2001 | } | |
2002 | ||
2003 | if (smap->type == IOMAP_HOLE || dmap->type == IOMAP_HOLE) { | |
2004 | *same = false; | |
2005 | return 0; | |
2006 | } | |
2007 | ||
2008 | id = dax_read_lock(); | |
2009 | ret = dax_iomap_direct_access(smap, pos1, ALIGN(pos1 + len, PAGE_SIZE), | |
2010 | &saddr, NULL); | |
2011 | if (ret < 0) | |
2012 | goto out_unlock; | |
2013 | ||
2014 | ret = dax_iomap_direct_access(dmap, pos2, ALIGN(pos2 + len, PAGE_SIZE), | |
2015 | &daddr, NULL); | |
2016 | if (ret < 0) | |
2017 | goto out_unlock; | |
2018 | ||
2019 | *same = !memcmp(saddr, daddr, len); | |
2020 | if (!*same) | |
2021 | len = 0; | |
2022 | dax_read_unlock(id); | |
2023 | return len; | |
2024 | ||
2025 | out_unlock: | |
2026 | dax_read_unlock(id); | |
2027 | return -EIO; | |
2028 | } | |
2029 | ||
2030 | int dax_dedupe_file_range_compare(struct inode *src, loff_t srcoff, | |
2031 | struct inode *dst, loff_t dstoff, loff_t len, bool *same, | |
2032 | const struct iomap_ops *ops) | |
2033 | { | |
2034 | struct iomap_iter src_iter = { | |
2035 | .inode = src, | |
2036 | .pos = srcoff, | |
2037 | .len = len, | |
2038 | .flags = IOMAP_DAX, | |
2039 | }; | |
2040 | struct iomap_iter dst_iter = { | |
2041 | .inode = dst, | |
2042 | .pos = dstoff, | |
2043 | .len = len, | |
2044 | .flags = IOMAP_DAX, | |
2045 | }; | |
0e79e373 | 2046 | int ret, compared = 0; |
6f7db389 | 2047 | |
0e79e373 SR |
2048 | while ((ret = iomap_iter(&src_iter, ops)) > 0 && |
2049 | (ret = iomap_iter(&dst_iter, ops)) > 0) { | |
e900ba10 SR |
2050 | compared = dax_range_compare_iter(&src_iter, &dst_iter, |
2051 | min(src_iter.len, dst_iter.len), same); | |
0e79e373 SR |
2052 | if (compared < 0) |
2053 | return ret; | |
2054 | src_iter.processed = dst_iter.processed = compared; | |
6f7db389 SR |
2055 | } |
2056 | return ret; | |
2057 | } | |
2058 | ||
2059 | int dax_remap_file_range_prep(struct file *file_in, loff_t pos_in, | |
2060 | struct file *file_out, loff_t pos_out, | |
2061 | loff_t *len, unsigned int remap_flags, | |
2062 | const struct iomap_ops *ops) | |
2063 | { | |
2064 | return __generic_remap_file_range_prep(file_in, pos_in, file_out, | |
2065 | pos_out, len, remap_flags, ops); | |
2066 | } | |
2067 | EXPORT_SYMBOL_GPL(dax_remap_file_range_prep); |