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d475c634 MW |
1 | /* |
2 | * fs/dax.c - Direct Access filesystem code | |
3 | * Copyright (c) 2013-2014 Intel Corporation | |
4 | * Author: Matthew Wilcox <matthew.r.wilcox@intel.com> | |
5 | * Author: Ross Zwisler <ross.zwisler@linux.intel.com> | |
6 | * | |
7 | * This program is free software; you can redistribute it and/or modify it | |
8 | * under the terms and conditions of the GNU General Public License, | |
9 | * version 2, as published by the Free Software Foundation. | |
10 | * | |
11 | * This program is distributed in the hope it will be useful, but WITHOUT | |
12 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
13 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for | |
14 | * more details. | |
15 | */ | |
16 | ||
17 | #include <linux/atomic.h> | |
18 | #include <linux/blkdev.h> | |
19 | #include <linux/buffer_head.h> | |
d77e92e2 | 20 | #include <linux/dax.h> |
d475c634 MW |
21 | #include <linux/fs.h> |
22 | #include <linux/genhd.h> | |
f7ca90b1 MW |
23 | #include <linux/highmem.h> |
24 | #include <linux/memcontrol.h> | |
25 | #include <linux/mm.h> | |
d475c634 | 26 | #include <linux/mutex.h> |
9973c98e | 27 | #include <linux/pagevec.h> |
289c6aed | 28 | #include <linux/sched.h> |
f361bf4a | 29 | #include <linux/sched/signal.h> |
d475c634 | 30 | #include <linux/uio.h> |
f7ca90b1 | 31 | #include <linux/vmstat.h> |
34c0fd54 | 32 | #include <linux/pfn_t.h> |
0e749e54 | 33 | #include <linux/sizes.h> |
4b4bb46d | 34 | #include <linux/mmu_notifier.h> |
a254e568 CH |
35 | #include <linux/iomap.h> |
36 | #include "internal.h" | |
d475c634 | 37 | |
282a8e03 RZ |
38 | #define CREATE_TRACE_POINTS |
39 | #include <trace/events/fs_dax.h> | |
40 | ||
ac401cc7 JK |
41 | /* We choose 4096 entries - same as per-zone page wait tables */ |
42 | #define DAX_WAIT_TABLE_BITS 12 | |
43 | #define DAX_WAIT_TABLE_ENTRIES (1 << DAX_WAIT_TABLE_BITS) | |
44 | ||
917f3452 RZ |
45 | /* The 'colour' (ie low bits) within a PMD of a page offset. */ |
46 | #define PG_PMD_COLOUR ((PMD_SIZE >> PAGE_SHIFT) - 1) | |
977fbdcd | 47 | #define PG_PMD_NR (PMD_SIZE >> PAGE_SHIFT) |
917f3452 | 48 | |
ce95ab0f | 49 | static wait_queue_head_t wait_table[DAX_WAIT_TABLE_ENTRIES]; |
ac401cc7 JK |
50 | |
51 | static int __init init_dax_wait_table(void) | |
52 | { | |
53 | int i; | |
54 | ||
55 | for (i = 0; i < DAX_WAIT_TABLE_ENTRIES; i++) | |
56 | init_waitqueue_head(wait_table + i); | |
57 | return 0; | |
58 | } | |
59 | fs_initcall(init_dax_wait_table); | |
60 | ||
527b19d0 RZ |
61 | /* |
62 | * We use lowest available bit in exceptional entry for locking, one bit for | |
63 | * the entry size (PMD) and two more to tell us if the entry is a zero page or | |
64 | * an empty entry that is just used for locking. In total four special bits. | |
65 | * | |
66 | * If the PMD bit isn't set the entry has size PAGE_SIZE, and if the ZERO_PAGE | |
67 | * and EMPTY bits aren't set the entry is a normal DAX entry with a filesystem | |
68 | * block allocation. | |
69 | */ | |
70 | #define RADIX_DAX_SHIFT (RADIX_TREE_EXCEPTIONAL_SHIFT + 4) | |
71 | #define RADIX_DAX_ENTRY_LOCK (1 << RADIX_TREE_EXCEPTIONAL_SHIFT) | |
72 | #define RADIX_DAX_PMD (1 << (RADIX_TREE_EXCEPTIONAL_SHIFT + 1)) | |
73 | #define RADIX_DAX_ZERO_PAGE (1 << (RADIX_TREE_EXCEPTIONAL_SHIFT + 2)) | |
74 | #define RADIX_DAX_EMPTY (1 << (RADIX_TREE_EXCEPTIONAL_SHIFT + 3)) | |
75 | ||
3fe0791c | 76 | static unsigned long dax_radix_pfn(void *entry) |
527b19d0 RZ |
77 | { |
78 | return (unsigned long)entry >> RADIX_DAX_SHIFT; | |
79 | } | |
80 | ||
3fe0791c | 81 | static void *dax_radix_locked_entry(unsigned long pfn, unsigned long flags) |
527b19d0 RZ |
82 | { |
83 | return (void *)(RADIX_TREE_EXCEPTIONAL_ENTRY | flags | | |
3fe0791c | 84 | (pfn << RADIX_DAX_SHIFT) | RADIX_DAX_ENTRY_LOCK); |
527b19d0 RZ |
85 | } |
86 | ||
87 | static unsigned int dax_radix_order(void *entry) | |
88 | { | |
89 | if ((unsigned long)entry & RADIX_DAX_PMD) | |
90 | return PMD_SHIFT - PAGE_SHIFT; | |
91 | return 0; | |
92 | } | |
93 | ||
642261ac | 94 | static int dax_is_pmd_entry(void *entry) |
d1a5f2b4 | 95 | { |
642261ac | 96 | return (unsigned long)entry & RADIX_DAX_PMD; |
d1a5f2b4 DW |
97 | } |
98 | ||
642261ac | 99 | static int dax_is_pte_entry(void *entry) |
d475c634 | 100 | { |
642261ac | 101 | return !((unsigned long)entry & RADIX_DAX_PMD); |
d475c634 MW |
102 | } |
103 | ||
642261ac | 104 | static int dax_is_zero_entry(void *entry) |
d475c634 | 105 | { |
91d25ba8 | 106 | return (unsigned long)entry & RADIX_DAX_ZERO_PAGE; |
d475c634 MW |
107 | } |
108 | ||
642261ac | 109 | static int dax_is_empty_entry(void *entry) |
b2e0d162 | 110 | { |
642261ac | 111 | return (unsigned long)entry & RADIX_DAX_EMPTY; |
b2e0d162 DW |
112 | } |
113 | ||
ac401cc7 JK |
114 | /* |
115 | * DAX radix tree locking | |
116 | */ | |
117 | struct exceptional_entry_key { | |
118 | struct address_space *mapping; | |
63e95b5c | 119 | pgoff_t entry_start; |
ac401cc7 JK |
120 | }; |
121 | ||
122 | struct wait_exceptional_entry_queue { | |
ac6424b9 | 123 | wait_queue_entry_t wait; |
ac401cc7 JK |
124 | struct exceptional_entry_key key; |
125 | }; | |
126 | ||
63e95b5c RZ |
127 | static wait_queue_head_t *dax_entry_waitqueue(struct address_space *mapping, |
128 | pgoff_t index, void *entry, struct exceptional_entry_key *key) | |
129 | { | |
130 | unsigned long hash; | |
131 | ||
132 | /* | |
133 | * If 'entry' is a PMD, align the 'index' that we use for the wait | |
134 | * queue to the start of that PMD. This ensures that all offsets in | |
135 | * the range covered by the PMD map to the same bit lock. | |
136 | */ | |
642261ac | 137 | if (dax_is_pmd_entry(entry)) |
917f3452 | 138 | index &= ~PG_PMD_COLOUR; |
63e95b5c RZ |
139 | |
140 | key->mapping = mapping; | |
141 | key->entry_start = index; | |
142 | ||
143 | hash = hash_long((unsigned long)mapping ^ index, DAX_WAIT_TABLE_BITS); | |
144 | return wait_table + hash; | |
145 | } | |
146 | ||
ac6424b9 | 147 | static int wake_exceptional_entry_func(wait_queue_entry_t *wait, unsigned int mode, |
ac401cc7 JK |
148 | int sync, void *keyp) |
149 | { | |
150 | struct exceptional_entry_key *key = keyp; | |
151 | struct wait_exceptional_entry_queue *ewait = | |
152 | container_of(wait, struct wait_exceptional_entry_queue, wait); | |
153 | ||
154 | if (key->mapping != ewait->key.mapping || | |
63e95b5c | 155 | key->entry_start != ewait->key.entry_start) |
ac401cc7 JK |
156 | return 0; |
157 | return autoremove_wake_function(wait, mode, sync, NULL); | |
158 | } | |
159 | ||
e30331ff | 160 | /* |
b93b0163 MW |
161 | * @entry may no longer be the entry at the index in the mapping. |
162 | * The important information it's conveying is whether the entry at | |
163 | * this index used to be a PMD entry. | |
e30331ff | 164 | */ |
d01ad197 | 165 | static void dax_wake_mapping_entry_waiter(struct address_space *mapping, |
e30331ff RZ |
166 | pgoff_t index, void *entry, bool wake_all) |
167 | { | |
168 | struct exceptional_entry_key key; | |
169 | wait_queue_head_t *wq; | |
170 | ||
171 | wq = dax_entry_waitqueue(mapping, index, entry, &key); | |
172 | ||
173 | /* | |
174 | * Checking for locked entry and prepare_to_wait_exclusive() happens | |
b93b0163 | 175 | * under the i_pages lock, ditto for entry handling in our callers. |
e30331ff RZ |
176 | * So at this point all tasks that could have seen our entry locked |
177 | * must be in the waitqueue and the following check will see them. | |
178 | */ | |
179 | if (waitqueue_active(wq)) | |
180 | __wake_up(wq, TASK_NORMAL, wake_all ? 0 : 1, &key); | |
181 | } | |
182 | ||
ac401cc7 | 183 | /* |
b93b0163 MW |
184 | * Check whether the given slot is locked. Must be called with the i_pages |
185 | * lock held. | |
ac401cc7 JK |
186 | */ |
187 | static inline int slot_locked(struct address_space *mapping, void **slot) | |
188 | { | |
189 | unsigned long entry = (unsigned long) | |
b93b0163 | 190 | radix_tree_deref_slot_protected(slot, &mapping->i_pages.xa_lock); |
ac401cc7 JK |
191 | return entry & RADIX_DAX_ENTRY_LOCK; |
192 | } | |
193 | ||
194 | /* | |
b93b0163 | 195 | * Mark the given slot as locked. Must be called with the i_pages lock held. |
ac401cc7 JK |
196 | */ |
197 | static inline void *lock_slot(struct address_space *mapping, void **slot) | |
198 | { | |
199 | unsigned long entry = (unsigned long) | |
b93b0163 | 200 | radix_tree_deref_slot_protected(slot, &mapping->i_pages.xa_lock); |
ac401cc7 JK |
201 | |
202 | entry |= RADIX_DAX_ENTRY_LOCK; | |
b93b0163 | 203 | radix_tree_replace_slot(&mapping->i_pages, slot, (void *)entry); |
ac401cc7 JK |
204 | return (void *)entry; |
205 | } | |
206 | ||
207 | /* | |
b93b0163 | 208 | * Mark the given slot as unlocked. Must be called with the i_pages lock held. |
ac401cc7 JK |
209 | */ |
210 | static inline void *unlock_slot(struct address_space *mapping, void **slot) | |
211 | { | |
212 | unsigned long entry = (unsigned long) | |
b93b0163 | 213 | radix_tree_deref_slot_protected(slot, &mapping->i_pages.xa_lock); |
ac401cc7 JK |
214 | |
215 | entry &= ~(unsigned long)RADIX_DAX_ENTRY_LOCK; | |
b93b0163 | 216 | radix_tree_replace_slot(&mapping->i_pages, slot, (void *)entry); |
ac401cc7 JK |
217 | return (void *)entry; |
218 | } | |
219 | ||
220 | /* | |
221 | * Lookup entry in radix tree, wait for it to become unlocked if it is | |
222 | * exceptional entry and return it. The caller must call | |
223 | * put_unlocked_mapping_entry() when he decided not to lock the entry or | |
224 | * put_locked_mapping_entry() when he locked the entry and now wants to | |
225 | * unlock it. | |
226 | * | |
b93b0163 | 227 | * Must be called with the i_pages lock held. |
ac401cc7 JK |
228 | */ |
229 | static void *get_unlocked_mapping_entry(struct address_space *mapping, | |
230 | pgoff_t index, void ***slotp) | |
231 | { | |
e3ad61c6 | 232 | void *entry, **slot; |
ac401cc7 | 233 | struct wait_exceptional_entry_queue ewait; |
63e95b5c | 234 | wait_queue_head_t *wq; |
ac401cc7 JK |
235 | |
236 | init_wait(&ewait.wait); | |
237 | ewait.wait.func = wake_exceptional_entry_func; | |
ac401cc7 JK |
238 | |
239 | for (;;) { | |
b93b0163 | 240 | entry = __radix_tree_lookup(&mapping->i_pages, index, NULL, |
ac401cc7 | 241 | &slot); |
91d25ba8 RZ |
242 | if (!entry || |
243 | WARN_ON_ONCE(!radix_tree_exceptional_entry(entry)) || | |
ac401cc7 JK |
244 | !slot_locked(mapping, slot)) { |
245 | if (slotp) | |
246 | *slotp = slot; | |
e3ad61c6 | 247 | return entry; |
ac401cc7 | 248 | } |
63e95b5c RZ |
249 | |
250 | wq = dax_entry_waitqueue(mapping, index, entry, &ewait.key); | |
ac401cc7 JK |
251 | prepare_to_wait_exclusive(wq, &ewait.wait, |
252 | TASK_UNINTERRUPTIBLE); | |
b93b0163 | 253 | xa_unlock_irq(&mapping->i_pages); |
ac401cc7 JK |
254 | schedule(); |
255 | finish_wait(wq, &ewait.wait); | |
b93b0163 | 256 | xa_lock_irq(&mapping->i_pages); |
ac401cc7 JK |
257 | } |
258 | } | |
259 | ||
b1aa812b JK |
260 | static void dax_unlock_mapping_entry(struct address_space *mapping, |
261 | pgoff_t index) | |
262 | { | |
263 | void *entry, **slot; | |
264 | ||
b93b0163 MW |
265 | xa_lock_irq(&mapping->i_pages); |
266 | entry = __radix_tree_lookup(&mapping->i_pages, index, NULL, &slot); | |
b1aa812b JK |
267 | if (WARN_ON_ONCE(!entry || !radix_tree_exceptional_entry(entry) || |
268 | !slot_locked(mapping, slot))) { | |
b93b0163 | 269 | xa_unlock_irq(&mapping->i_pages); |
b1aa812b JK |
270 | return; |
271 | } | |
272 | unlock_slot(mapping, slot); | |
b93b0163 | 273 | xa_unlock_irq(&mapping->i_pages); |
b1aa812b JK |
274 | dax_wake_mapping_entry_waiter(mapping, index, entry, false); |
275 | } | |
276 | ||
422476c4 | 277 | static void put_locked_mapping_entry(struct address_space *mapping, |
91d25ba8 | 278 | pgoff_t index) |
422476c4 | 279 | { |
91d25ba8 | 280 | dax_unlock_mapping_entry(mapping, index); |
422476c4 RZ |
281 | } |
282 | ||
283 | /* | |
284 | * Called when we are done with radix tree entry we looked up via | |
285 | * get_unlocked_mapping_entry() and which we didn't lock in the end. | |
286 | */ | |
287 | static void put_unlocked_mapping_entry(struct address_space *mapping, | |
288 | pgoff_t index, void *entry) | |
289 | { | |
91d25ba8 | 290 | if (!entry) |
422476c4 RZ |
291 | return; |
292 | ||
293 | /* We have to wake up next waiter for the radix tree entry lock */ | |
294 | dax_wake_mapping_entry_waiter(mapping, index, entry, false); | |
295 | } | |
296 | ||
d2c997c0 DW |
297 | static unsigned long dax_entry_size(void *entry) |
298 | { | |
299 | if (dax_is_zero_entry(entry)) | |
300 | return 0; | |
301 | else if (dax_is_empty_entry(entry)) | |
302 | return 0; | |
303 | else if (dax_is_pmd_entry(entry)) | |
304 | return PMD_SIZE; | |
305 | else | |
306 | return PAGE_SIZE; | |
307 | } | |
308 | ||
309 | static unsigned long dax_radix_end_pfn(void *entry) | |
310 | { | |
311 | return dax_radix_pfn(entry) + dax_entry_size(entry) / PAGE_SIZE; | |
312 | } | |
313 | ||
314 | /* | |
315 | * Iterate through all mapped pfns represented by an entry, i.e. skip | |
316 | * 'empty' and 'zero' entries. | |
317 | */ | |
318 | #define for_each_mapped_pfn(entry, pfn) \ | |
319 | for (pfn = dax_radix_pfn(entry); \ | |
320 | pfn < dax_radix_end_pfn(entry); pfn++) | |
321 | ||
322 | static void dax_associate_entry(void *entry, struct address_space *mapping) | |
323 | { | |
324 | unsigned long pfn; | |
325 | ||
326 | if (IS_ENABLED(CONFIG_FS_DAX_LIMITED)) | |
327 | return; | |
328 | ||
329 | for_each_mapped_pfn(entry, pfn) { | |
330 | struct page *page = pfn_to_page(pfn); | |
331 | ||
332 | WARN_ON_ONCE(page->mapping); | |
333 | page->mapping = mapping; | |
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; | |
351 | } | |
352 | } | |
353 | ||
5fac7408 DW |
354 | static struct page *dax_busy_page(void *entry) |
355 | { | |
356 | unsigned long pfn; | |
357 | ||
358 | for_each_mapped_pfn(entry, pfn) { | |
359 | struct page *page = pfn_to_page(pfn); | |
360 | ||
361 | if (page_ref_count(page) > 1) | |
362 | return page; | |
363 | } | |
364 | return NULL; | |
365 | } | |
366 | ||
ac401cc7 | 367 | /* |
91d25ba8 RZ |
368 | * Find radix tree entry at given index. If it points to an exceptional entry, |
369 | * return it with the radix tree entry locked. If the radix tree doesn't | |
370 | * contain given index, create an empty exceptional entry for the index and | |
371 | * return with it locked. | |
ac401cc7 | 372 | * |
642261ac RZ |
373 | * When requesting an entry with size RADIX_DAX_PMD, grab_mapping_entry() will |
374 | * either return that locked entry or will return an error. This error will | |
91d25ba8 RZ |
375 | * happen if there are any 4k entries within the 2MiB range that we are |
376 | * requesting. | |
642261ac RZ |
377 | * |
378 | * We always favor 4k entries over 2MiB entries. There isn't a flow where we | |
379 | * evict 4k entries in order to 'upgrade' them to a 2MiB entry. A 2MiB | |
380 | * insertion will fail if it finds any 4k entries already in the tree, and a | |
381 | * 4k insertion will cause an existing 2MiB entry to be unmapped and | |
382 | * downgraded to 4k entries. This happens for both 2MiB huge zero pages as | |
383 | * well as 2MiB empty entries. | |
384 | * | |
385 | * The exception to this downgrade path is for 2MiB DAX PMD entries that have | |
386 | * real storage backing them. We will leave these real 2MiB DAX entries in | |
387 | * the tree, and PTE writes will simply dirty the entire 2MiB DAX entry. | |
388 | * | |
ac401cc7 JK |
389 | * Note: Unlike filemap_fault() we don't honor FAULT_FLAG_RETRY flags. For |
390 | * persistent memory the benefit is doubtful. We can add that later if we can | |
391 | * show it helps. | |
392 | */ | |
642261ac RZ |
393 | static void *grab_mapping_entry(struct address_space *mapping, pgoff_t index, |
394 | unsigned long size_flag) | |
ac401cc7 | 395 | { |
642261ac | 396 | bool pmd_downgrade = false; /* splitting 2MiB entry into 4k entries? */ |
e3ad61c6 | 397 | void *entry, **slot; |
ac401cc7 JK |
398 | |
399 | restart: | |
b93b0163 | 400 | xa_lock_irq(&mapping->i_pages); |
e3ad61c6 | 401 | entry = get_unlocked_mapping_entry(mapping, index, &slot); |
642261ac | 402 | |
91d25ba8 RZ |
403 | if (WARN_ON_ONCE(entry && !radix_tree_exceptional_entry(entry))) { |
404 | entry = ERR_PTR(-EIO); | |
405 | goto out_unlock; | |
406 | } | |
407 | ||
642261ac RZ |
408 | if (entry) { |
409 | if (size_flag & RADIX_DAX_PMD) { | |
91d25ba8 | 410 | if (dax_is_pte_entry(entry)) { |
642261ac RZ |
411 | put_unlocked_mapping_entry(mapping, index, |
412 | entry); | |
413 | entry = ERR_PTR(-EEXIST); | |
414 | goto out_unlock; | |
415 | } | |
416 | } else { /* trying to grab a PTE entry */ | |
91d25ba8 | 417 | if (dax_is_pmd_entry(entry) && |
642261ac RZ |
418 | (dax_is_zero_entry(entry) || |
419 | dax_is_empty_entry(entry))) { | |
420 | pmd_downgrade = true; | |
421 | } | |
422 | } | |
423 | } | |
424 | ||
ac401cc7 | 425 | /* No entry for given index? Make sure radix tree is big enough. */ |
642261ac | 426 | if (!entry || pmd_downgrade) { |
ac401cc7 JK |
427 | int err; |
428 | ||
642261ac RZ |
429 | if (pmd_downgrade) { |
430 | /* | |
431 | * Make sure 'entry' remains valid while we drop | |
b93b0163 | 432 | * the i_pages lock. |
642261ac RZ |
433 | */ |
434 | entry = lock_slot(mapping, slot); | |
435 | } | |
436 | ||
b93b0163 | 437 | xa_unlock_irq(&mapping->i_pages); |
642261ac RZ |
438 | /* |
439 | * Besides huge zero pages the only other thing that gets | |
440 | * downgraded are empty entries which don't need to be | |
441 | * unmapped. | |
442 | */ | |
443 | if (pmd_downgrade && dax_is_zero_entry(entry)) | |
977fbdcd MW |
444 | unmap_mapping_pages(mapping, index & ~PG_PMD_COLOUR, |
445 | PG_PMD_NR, false); | |
642261ac | 446 | |
ac401cc7 JK |
447 | err = radix_tree_preload( |
448 | mapping_gfp_mask(mapping) & ~__GFP_HIGHMEM); | |
0cb80b48 JK |
449 | if (err) { |
450 | if (pmd_downgrade) | |
91d25ba8 | 451 | put_locked_mapping_entry(mapping, index); |
ac401cc7 | 452 | return ERR_PTR(err); |
0cb80b48 | 453 | } |
b93b0163 | 454 | xa_lock_irq(&mapping->i_pages); |
642261ac | 455 | |
e11f8b7b RZ |
456 | if (!entry) { |
457 | /* | |
b93b0163 | 458 | * We needed to drop the i_pages lock while calling |
e11f8b7b RZ |
459 | * radix_tree_preload() and we didn't have an entry to |
460 | * lock. See if another thread inserted an entry at | |
461 | * our index during this time. | |
462 | */ | |
b93b0163 | 463 | entry = __radix_tree_lookup(&mapping->i_pages, index, |
e11f8b7b RZ |
464 | NULL, &slot); |
465 | if (entry) { | |
466 | radix_tree_preload_end(); | |
b93b0163 | 467 | xa_unlock_irq(&mapping->i_pages); |
e11f8b7b RZ |
468 | goto restart; |
469 | } | |
470 | } | |
471 | ||
642261ac | 472 | if (pmd_downgrade) { |
d2c997c0 | 473 | dax_disassociate_entry(entry, mapping, false); |
b93b0163 | 474 | radix_tree_delete(&mapping->i_pages, index); |
642261ac RZ |
475 | mapping->nrexceptional--; |
476 | dax_wake_mapping_entry_waiter(mapping, index, entry, | |
477 | true); | |
478 | } | |
479 | ||
480 | entry = dax_radix_locked_entry(0, size_flag | RADIX_DAX_EMPTY); | |
481 | ||
b93b0163 | 482 | err = __radix_tree_insert(&mapping->i_pages, index, |
642261ac | 483 | dax_radix_order(entry), entry); |
ac401cc7 JK |
484 | radix_tree_preload_end(); |
485 | if (err) { | |
b93b0163 | 486 | xa_unlock_irq(&mapping->i_pages); |
642261ac | 487 | /* |
e11f8b7b RZ |
488 | * Our insertion of a DAX entry failed, most likely |
489 | * because we were inserting a PMD entry and it | |
490 | * collided with a PTE sized entry at a different | |
491 | * index in the PMD range. We haven't inserted | |
492 | * anything into the radix tree and have no waiters to | |
493 | * wake. | |
642261ac | 494 | */ |
ac401cc7 JK |
495 | return ERR_PTR(err); |
496 | } | |
497 | /* Good, we have inserted empty locked entry into the tree. */ | |
498 | mapping->nrexceptional++; | |
b93b0163 | 499 | xa_unlock_irq(&mapping->i_pages); |
e3ad61c6 | 500 | return entry; |
ac401cc7 | 501 | } |
e3ad61c6 | 502 | entry = lock_slot(mapping, slot); |
642261ac | 503 | out_unlock: |
b93b0163 | 504 | xa_unlock_irq(&mapping->i_pages); |
e3ad61c6 | 505 | return entry; |
ac401cc7 JK |
506 | } |
507 | ||
5fac7408 DW |
508 | /** |
509 | * dax_layout_busy_page - find first pinned page in @mapping | |
510 | * @mapping: address space to scan for a page with ref count > 1 | |
511 | * | |
512 | * DAX requires ZONE_DEVICE mapped pages. These pages are never | |
513 | * 'onlined' to the page allocator so they are considered idle when | |
514 | * page->count == 1. A filesystem uses this interface to determine if | |
515 | * any page in the mapping is busy, i.e. for DMA, or other | |
516 | * get_user_pages() usages. | |
517 | * | |
518 | * It is expected that the filesystem is holding locks to block the | |
519 | * establishment of new mappings in this address_space. I.e. it expects | |
520 | * to be able to run unmap_mapping_range() and subsequently not race | |
521 | * mapping_mapped() becoming true. | |
522 | */ | |
523 | struct page *dax_layout_busy_page(struct address_space *mapping) | |
524 | { | |
525 | pgoff_t indices[PAGEVEC_SIZE]; | |
526 | struct page *page = NULL; | |
527 | struct pagevec pvec; | |
528 | pgoff_t index, end; | |
529 | unsigned i; | |
530 | ||
531 | /* | |
532 | * In the 'limited' case get_user_pages() for dax is disabled. | |
533 | */ | |
534 | if (IS_ENABLED(CONFIG_FS_DAX_LIMITED)) | |
535 | return NULL; | |
536 | ||
537 | if (!dax_mapping(mapping) || !mapping_mapped(mapping)) | |
538 | return NULL; | |
539 | ||
540 | pagevec_init(&pvec); | |
541 | index = 0; | |
542 | end = -1; | |
543 | ||
544 | /* | |
545 | * If we race get_user_pages_fast() here either we'll see the | |
546 | * elevated page count in the pagevec_lookup and wait, or | |
547 | * get_user_pages_fast() will see that the page it took a reference | |
548 | * against is no longer mapped in the page tables and bail to the | |
549 | * get_user_pages() slow path. The slow path is protected by | |
550 | * pte_lock() and pmd_lock(). New references are not taken without | |
551 | * holding those locks, and unmap_mapping_range() will not zero the | |
552 | * pte or pmd without holding the respective lock, so we are | |
553 | * guaranteed to either see new references or prevent new | |
554 | * references from being established. | |
555 | */ | |
556 | unmap_mapping_range(mapping, 0, 0, 1); | |
557 | ||
558 | while (index < end && pagevec_lookup_entries(&pvec, mapping, index, | |
559 | min(end - index, (pgoff_t)PAGEVEC_SIZE), | |
560 | indices)) { | |
561 | for (i = 0; i < pagevec_count(&pvec); i++) { | |
562 | struct page *pvec_ent = pvec.pages[i]; | |
563 | void *entry; | |
564 | ||
565 | index = indices[i]; | |
566 | if (index >= end) | |
567 | break; | |
568 | ||
cdbf8897 RZ |
569 | if (WARN_ON_ONCE( |
570 | !radix_tree_exceptional_entry(pvec_ent))) | |
5fac7408 DW |
571 | continue; |
572 | ||
573 | xa_lock_irq(&mapping->i_pages); | |
574 | entry = get_unlocked_mapping_entry(mapping, index, NULL); | |
575 | if (entry) | |
576 | page = dax_busy_page(entry); | |
577 | put_unlocked_mapping_entry(mapping, index, entry); | |
578 | xa_unlock_irq(&mapping->i_pages); | |
579 | if (page) | |
580 | break; | |
581 | } | |
cdbf8897 RZ |
582 | |
583 | /* | |
584 | * We don't expect normal struct page entries to exist in our | |
585 | * tree, but we keep these pagevec calls so that this code is | |
586 | * consistent with the common pattern for handling pagevecs | |
587 | * throughout the kernel. | |
588 | */ | |
5fac7408 DW |
589 | pagevec_remove_exceptionals(&pvec); |
590 | pagevec_release(&pvec); | |
591 | index++; | |
592 | ||
593 | if (page) | |
594 | break; | |
595 | } | |
596 | return page; | |
597 | } | |
598 | EXPORT_SYMBOL_GPL(dax_layout_busy_page); | |
599 | ||
c6dcf52c JK |
600 | static int __dax_invalidate_mapping_entry(struct address_space *mapping, |
601 | pgoff_t index, bool trunc) | |
602 | { | |
603 | int ret = 0; | |
604 | void *entry; | |
b93b0163 | 605 | struct radix_tree_root *pages = &mapping->i_pages; |
c6dcf52c | 606 | |
b93b0163 | 607 | xa_lock_irq(pages); |
c6dcf52c | 608 | entry = get_unlocked_mapping_entry(mapping, index, NULL); |
91d25ba8 | 609 | if (!entry || WARN_ON_ONCE(!radix_tree_exceptional_entry(entry))) |
c6dcf52c JK |
610 | goto out; |
611 | if (!trunc && | |
b93b0163 MW |
612 | (radix_tree_tag_get(pages, index, PAGECACHE_TAG_DIRTY) || |
613 | radix_tree_tag_get(pages, index, PAGECACHE_TAG_TOWRITE))) | |
c6dcf52c | 614 | goto out; |
d2c997c0 | 615 | dax_disassociate_entry(entry, mapping, trunc); |
b93b0163 | 616 | radix_tree_delete(pages, index); |
c6dcf52c JK |
617 | mapping->nrexceptional--; |
618 | ret = 1; | |
619 | out: | |
620 | put_unlocked_mapping_entry(mapping, index, entry); | |
b93b0163 | 621 | xa_unlock_irq(pages); |
c6dcf52c JK |
622 | return ret; |
623 | } | |
ac401cc7 JK |
624 | /* |
625 | * Delete exceptional DAX entry at @index from @mapping. Wait for radix tree | |
626 | * entry to get unlocked before deleting it. | |
627 | */ | |
628 | int dax_delete_mapping_entry(struct address_space *mapping, pgoff_t index) | |
629 | { | |
c6dcf52c | 630 | int ret = __dax_invalidate_mapping_entry(mapping, index, true); |
ac401cc7 | 631 | |
ac401cc7 JK |
632 | /* |
633 | * This gets called from truncate / punch_hole path. As such, the caller | |
634 | * must hold locks protecting against concurrent modifications of the | |
635 | * radix tree (usually fs-private i_mmap_sem for writing). Since the | |
636 | * caller has seen exceptional entry for this index, we better find it | |
637 | * at that index as well... | |
638 | */ | |
c6dcf52c JK |
639 | WARN_ON_ONCE(!ret); |
640 | return ret; | |
641 | } | |
642 | ||
c6dcf52c JK |
643 | /* |
644 | * Invalidate exceptional DAX entry if it is clean. | |
645 | */ | |
646 | int dax_invalidate_mapping_entry_sync(struct address_space *mapping, | |
647 | pgoff_t index) | |
648 | { | |
649 | return __dax_invalidate_mapping_entry(mapping, index, false); | |
ac401cc7 JK |
650 | } |
651 | ||
cccbce67 DW |
652 | static int copy_user_dax(struct block_device *bdev, struct dax_device *dax_dev, |
653 | sector_t sector, size_t size, struct page *to, | |
654 | unsigned long vaddr) | |
f7ca90b1 | 655 | { |
cccbce67 DW |
656 | void *vto, *kaddr; |
657 | pgoff_t pgoff; | |
658 | pfn_t pfn; | |
659 | long rc; | |
660 | int id; | |
661 | ||
662 | rc = bdev_dax_pgoff(bdev, sector, size, &pgoff); | |
663 | if (rc) | |
664 | return rc; | |
665 | ||
666 | id = dax_read_lock(); | |
667 | rc = dax_direct_access(dax_dev, pgoff, PHYS_PFN(size), &kaddr, &pfn); | |
668 | if (rc < 0) { | |
669 | dax_read_unlock(id); | |
670 | return rc; | |
671 | } | |
f7ca90b1 | 672 | vto = kmap_atomic(to); |
cccbce67 | 673 | copy_user_page(vto, (void __force *)kaddr, vaddr, to); |
f7ca90b1 | 674 | kunmap_atomic(vto); |
cccbce67 | 675 | dax_read_unlock(id); |
f7ca90b1 MW |
676 | return 0; |
677 | } | |
678 | ||
642261ac RZ |
679 | /* |
680 | * By this point grab_mapping_entry() has ensured that we have a locked entry | |
681 | * of the appropriate size so we don't have to worry about downgrading PMDs to | |
682 | * PTEs. If we happen to be trying to insert a PTE and there is a PMD | |
683 | * already in the tree, we will skip the insertion and just dirty the PMD as | |
684 | * appropriate. | |
685 | */ | |
ac401cc7 JK |
686 | static void *dax_insert_mapping_entry(struct address_space *mapping, |
687 | struct vm_fault *vmf, | |
3fe0791c | 688 | void *entry, pfn_t pfn_t, |
f5b7b748 | 689 | unsigned long flags, bool dirty) |
9973c98e | 690 | { |
b93b0163 | 691 | struct radix_tree_root *pages = &mapping->i_pages; |
3fe0791c | 692 | unsigned long pfn = pfn_t_to_pfn(pfn_t); |
ac401cc7 | 693 | pgoff_t index = vmf->pgoff; |
3fe0791c | 694 | void *new_entry; |
9973c98e | 695 | |
f5b7b748 | 696 | if (dirty) |
d2b2a28e | 697 | __mark_inode_dirty(mapping->host, I_DIRTY_PAGES); |
9973c98e | 698 | |
91d25ba8 RZ |
699 | if (dax_is_zero_entry(entry) && !(flags & RADIX_DAX_ZERO_PAGE)) { |
700 | /* we are replacing a zero page with block mapping */ | |
701 | if (dax_is_pmd_entry(entry)) | |
977fbdcd MW |
702 | unmap_mapping_pages(mapping, index & ~PG_PMD_COLOUR, |
703 | PG_PMD_NR, false); | |
91d25ba8 | 704 | else /* pte entry */ |
977fbdcd | 705 | unmap_mapping_pages(mapping, vmf->pgoff, 1, false); |
9973c98e RZ |
706 | } |
707 | ||
b93b0163 | 708 | xa_lock_irq(pages); |
3fe0791c | 709 | new_entry = dax_radix_locked_entry(pfn, flags); |
d2c997c0 DW |
710 | if (dax_entry_size(entry) != dax_entry_size(new_entry)) { |
711 | dax_disassociate_entry(entry, mapping, false); | |
712 | dax_associate_entry(new_entry, mapping); | |
713 | } | |
642261ac | 714 | |
91d25ba8 | 715 | if (dax_is_zero_entry(entry) || dax_is_empty_entry(entry)) { |
642261ac RZ |
716 | /* |
717 | * Only swap our new entry into the radix tree if the current | |
718 | * entry is a zero page or an empty entry. If a normal PTE or | |
719 | * PMD entry is already in the tree, we leave it alone. This | |
720 | * means that if we are trying to insert a PTE and the | |
721 | * existing entry is a PMD, we will just leave the PMD in the | |
722 | * tree and dirty it if necessary. | |
723 | */ | |
f7942430 | 724 | struct radix_tree_node *node; |
ac401cc7 JK |
725 | void **slot; |
726 | void *ret; | |
9973c98e | 727 | |
b93b0163 | 728 | ret = __radix_tree_lookup(pages, index, &node, &slot); |
ac401cc7 | 729 | WARN_ON_ONCE(ret != entry); |
b93b0163 | 730 | __radix_tree_replace(pages, node, slot, |
c7df8ad2 | 731 | new_entry, NULL); |
91d25ba8 | 732 | entry = new_entry; |
9973c98e | 733 | } |
91d25ba8 | 734 | |
f5b7b748 | 735 | if (dirty) |
b93b0163 | 736 | radix_tree_tag_set(pages, index, PAGECACHE_TAG_DIRTY); |
91d25ba8 | 737 | |
b93b0163 | 738 | xa_unlock_irq(pages); |
91d25ba8 | 739 | return entry; |
9973c98e RZ |
740 | } |
741 | ||
4b4bb46d JK |
742 | static inline unsigned long |
743 | pgoff_address(pgoff_t pgoff, struct vm_area_struct *vma) | |
744 | { | |
745 | unsigned long address; | |
746 | ||
747 | address = vma->vm_start + ((pgoff - vma->vm_pgoff) << PAGE_SHIFT); | |
748 | VM_BUG_ON_VMA(address < vma->vm_start || address >= vma->vm_end, vma); | |
749 | return address; | |
750 | } | |
751 | ||
752 | /* Walk all mappings of a given index of a file and writeprotect them */ | |
753 | static void dax_mapping_entry_mkclean(struct address_space *mapping, | |
754 | pgoff_t index, unsigned long pfn) | |
755 | { | |
756 | struct vm_area_struct *vma; | |
f729c8c9 RZ |
757 | pte_t pte, *ptep = NULL; |
758 | pmd_t *pmdp = NULL; | |
4b4bb46d | 759 | spinlock_t *ptl; |
4b4bb46d JK |
760 | |
761 | i_mmap_lock_read(mapping); | |
762 | vma_interval_tree_foreach(vma, &mapping->i_mmap, index, index) { | |
a4d1a885 | 763 | unsigned long address, start, end; |
4b4bb46d JK |
764 | |
765 | cond_resched(); | |
766 | ||
767 | if (!(vma->vm_flags & VM_SHARED)) | |
768 | continue; | |
769 | ||
770 | address = pgoff_address(index, vma); | |
a4d1a885 JG |
771 | |
772 | /* | |
773 | * Note because we provide start/end to follow_pte_pmd it will | |
774 | * call mmu_notifier_invalidate_range_start() on our behalf | |
775 | * before taking any lock. | |
776 | */ | |
777 | if (follow_pte_pmd(vma->vm_mm, address, &start, &end, &ptep, &pmdp, &ptl)) | |
4b4bb46d | 778 | continue; |
4b4bb46d | 779 | |
0f10851e JG |
780 | /* |
781 | * No need to call mmu_notifier_invalidate_range() as we are | |
782 | * downgrading page table protection not changing it to point | |
783 | * to a new page. | |
784 | * | |
ad56b738 | 785 | * See Documentation/vm/mmu_notifier.rst |
0f10851e | 786 | */ |
f729c8c9 RZ |
787 | if (pmdp) { |
788 | #ifdef CONFIG_FS_DAX_PMD | |
789 | pmd_t pmd; | |
790 | ||
791 | if (pfn != pmd_pfn(*pmdp)) | |
792 | goto unlock_pmd; | |
f6f37321 | 793 | if (!pmd_dirty(*pmdp) && !pmd_write(*pmdp)) |
f729c8c9 RZ |
794 | goto unlock_pmd; |
795 | ||
796 | flush_cache_page(vma, address, pfn); | |
797 | pmd = pmdp_huge_clear_flush(vma, address, pmdp); | |
798 | pmd = pmd_wrprotect(pmd); | |
799 | pmd = pmd_mkclean(pmd); | |
800 | set_pmd_at(vma->vm_mm, address, pmdp, pmd); | |
f729c8c9 | 801 | unlock_pmd: |
f729c8c9 | 802 | #endif |
ee190ca6 | 803 | spin_unlock(ptl); |
f729c8c9 RZ |
804 | } else { |
805 | if (pfn != pte_pfn(*ptep)) | |
806 | goto unlock_pte; | |
807 | if (!pte_dirty(*ptep) && !pte_write(*ptep)) | |
808 | goto unlock_pte; | |
809 | ||
810 | flush_cache_page(vma, address, pfn); | |
811 | pte = ptep_clear_flush(vma, address, ptep); | |
812 | pte = pte_wrprotect(pte); | |
813 | pte = pte_mkclean(pte); | |
814 | set_pte_at(vma->vm_mm, address, ptep, pte); | |
f729c8c9 RZ |
815 | unlock_pte: |
816 | pte_unmap_unlock(ptep, ptl); | |
817 | } | |
4b4bb46d | 818 | |
a4d1a885 | 819 | mmu_notifier_invalidate_range_end(vma->vm_mm, start, end); |
4b4bb46d JK |
820 | } |
821 | i_mmap_unlock_read(mapping); | |
822 | } | |
823 | ||
3fe0791c DW |
824 | static int dax_writeback_one(struct dax_device *dax_dev, |
825 | struct address_space *mapping, pgoff_t index, void *entry) | |
9973c98e | 826 | { |
b93b0163 | 827 | struct radix_tree_root *pages = &mapping->i_pages; |
3fe0791c DW |
828 | void *entry2, **slot; |
829 | unsigned long pfn; | |
830 | long ret = 0; | |
cccbce67 | 831 | size_t size; |
9973c98e | 832 | |
9973c98e | 833 | /* |
a6abc2c0 JK |
834 | * A page got tagged dirty in DAX mapping? Something is seriously |
835 | * wrong. | |
9973c98e | 836 | */ |
a6abc2c0 JK |
837 | if (WARN_ON(!radix_tree_exceptional_entry(entry))) |
838 | return -EIO; | |
9973c98e | 839 | |
b93b0163 | 840 | xa_lock_irq(pages); |
a6abc2c0 JK |
841 | entry2 = get_unlocked_mapping_entry(mapping, index, &slot); |
842 | /* Entry got punched out / reallocated? */ | |
91d25ba8 | 843 | if (!entry2 || WARN_ON_ONCE(!radix_tree_exceptional_entry(entry2))) |
a6abc2c0 JK |
844 | goto put_unlocked; |
845 | /* | |
846 | * Entry got reallocated elsewhere? No need to writeback. We have to | |
3fe0791c | 847 | * compare pfns as we must not bail out due to difference in lockbit |
a6abc2c0 JK |
848 | * or entry type. |
849 | */ | |
3fe0791c | 850 | if (dax_radix_pfn(entry2) != dax_radix_pfn(entry)) |
a6abc2c0 | 851 | goto put_unlocked; |
642261ac RZ |
852 | if (WARN_ON_ONCE(dax_is_empty_entry(entry) || |
853 | dax_is_zero_entry(entry))) { | |
9973c98e | 854 | ret = -EIO; |
a6abc2c0 | 855 | goto put_unlocked; |
9973c98e RZ |
856 | } |
857 | ||
a6abc2c0 | 858 | /* Another fsync thread may have already written back this entry */ |
b93b0163 | 859 | if (!radix_tree_tag_get(pages, index, PAGECACHE_TAG_TOWRITE)) |
a6abc2c0 JK |
860 | goto put_unlocked; |
861 | /* Lock the entry to serialize with page faults */ | |
862 | entry = lock_slot(mapping, slot); | |
863 | /* | |
864 | * We can clear the tag now but we have to be careful so that concurrent | |
865 | * dax_writeback_one() calls for the same index cannot finish before we | |
866 | * actually flush the caches. This is achieved as the calls will look | |
b93b0163 MW |
867 | * at the entry only under the i_pages lock and once they do that |
868 | * they will see the entry locked and wait for it to unlock. | |
a6abc2c0 | 869 | */ |
b93b0163 MW |
870 | radix_tree_tag_clear(pages, index, PAGECACHE_TAG_TOWRITE); |
871 | xa_unlock_irq(pages); | |
a6abc2c0 | 872 | |
642261ac RZ |
873 | /* |
874 | * Even if dax_writeback_mapping_range() was given a wbc->range_start | |
875 | * in the middle of a PMD, the 'index' we are given will be aligned to | |
3fe0791c DW |
876 | * the start index of the PMD, as will the pfn we pull from 'entry'. |
877 | * This allows us to flush for PMD_SIZE and not have to worry about | |
878 | * partial PMD writebacks. | |
642261ac | 879 | */ |
3fe0791c | 880 | pfn = dax_radix_pfn(entry); |
cccbce67 DW |
881 | size = PAGE_SIZE << dax_radix_order(entry); |
882 | ||
3fe0791c DW |
883 | dax_mapping_entry_mkclean(mapping, index, pfn); |
884 | dax_flush(dax_dev, page_address(pfn_to_page(pfn)), size); | |
4b4bb46d JK |
885 | /* |
886 | * After we have flushed the cache, we can clear the dirty tag. There | |
887 | * cannot be new dirty data in the pfn after the flush has completed as | |
888 | * the pfn mappings are writeprotected and fault waits for mapping | |
889 | * entry lock. | |
890 | */ | |
b93b0163 MW |
891 | xa_lock_irq(pages); |
892 | radix_tree_tag_clear(pages, index, PAGECACHE_TAG_DIRTY); | |
893 | xa_unlock_irq(pages); | |
f9bc3a07 | 894 | trace_dax_writeback_one(mapping->host, index, size >> PAGE_SHIFT); |
91d25ba8 | 895 | put_locked_mapping_entry(mapping, index); |
9973c98e RZ |
896 | return ret; |
897 | ||
a6abc2c0 JK |
898 | put_unlocked: |
899 | put_unlocked_mapping_entry(mapping, index, entry2); | |
b93b0163 | 900 | xa_unlock_irq(pages); |
9973c98e RZ |
901 | return ret; |
902 | } | |
903 | ||
904 | /* | |
905 | * Flush the mapping to the persistent domain within the byte range of [start, | |
906 | * end]. This is required by data integrity operations to ensure file data is | |
907 | * on persistent storage prior to completion of the operation. | |
908 | */ | |
7f6d5b52 RZ |
909 | int dax_writeback_mapping_range(struct address_space *mapping, |
910 | struct block_device *bdev, struct writeback_control *wbc) | |
9973c98e RZ |
911 | { |
912 | struct inode *inode = mapping->host; | |
642261ac | 913 | pgoff_t start_index, end_index; |
9973c98e | 914 | pgoff_t indices[PAGEVEC_SIZE]; |
cccbce67 | 915 | struct dax_device *dax_dev; |
9973c98e RZ |
916 | struct pagevec pvec; |
917 | bool done = false; | |
918 | int i, ret = 0; | |
9973c98e RZ |
919 | |
920 | if (WARN_ON_ONCE(inode->i_blkbits != PAGE_SHIFT)) | |
921 | return -EIO; | |
922 | ||
7f6d5b52 RZ |
923 | if (!mapping->nrexceptional || wbc->sync_mode != WB_SYNC_ALL) |
924 | return 0; | |
925 | ||
cccbce67 DW |
926 | dax_dev = dax_get_by_host(bdev->bd_disk->disk_name); |
927 | if (!dax_dev) | |
928 | return -EIO; | |
929 | ||
09cbfeaf KS |
930 | start_index = wbc->range_start >> PAGE_SHIFT; |
931 | end_index = wbc->range_end >> PAGE_SHIFT; | |
9973c98e | 932 | |
d14a3f48 RZ |
933 | trace_dax_writeback_range(inode, start_index, end_index); |
934 | ||
9973c98e RZ |
935 | tag_pages_for_writeback(mapping, start_index, end_index); |
936 | ||
86679820 | 937 | pagevec_init(&pvec); |
9973c98e RZ |
938 | while (!done) { |
939 | pvec.nr = find_get_entries_tag(mapping, start_index, | |
940 | PAGECACHE_TAG_TOWRITE, PAGEVEC_SIZE, | |
941 | pvec.pages, indices); | |
942 | ||
943 | if (pvec.nr == 0) | |
944 | break; | |
945 | ||
946 | for (i = 0; i < pvec.nr; i++) { | |
947 | if (indices[i] > end_index) { | |
948 | done = true; | |
949 | break; | |
950 | } | |
951 | ||
3fe0791c DW |
952 | ret = dax_writeback_one(dax_dev, mapping, indices[i], |
953 | pvec.pages[i]); | |
819ec6b9 JL |
954 | if (ret < 0) { |
955 | mapping_set_error(mapping, ret); | |
d14a3f48 | 956 | goto out; |
819ec6b9 | 957 | } |
9973c98e | 958 | } |
1eb643d0 | 959 | start_index = indices[pvec.nr - 1] + 1; |
9973c98e | 960 | } |
d14a3f48 | 961 | out: |
cccbce67 | 962 | put_dax(dax_dev); |
d14a3f48 RZ |
963 | trace_dax_writeback_range_done(inode, start_index, end_index); |
964 | return (ret < 0 ? ret : 0); | |
9973c98e RZ |
965 | } |
966 | EXPORT_SYMBOL_GPL(dax_writeback_mapping_range); | |
967 | ||
31a6f1a6 | 968 | static sector_t dax_iomap_sector(struct iomap *iomap, loff_t pos) |
f7ca90b1 | 969 | { |
a3841f94 | 970 | return (iomap->addr + (pos & PAGE_MASK) - iomap->offset) >> 9; |
31a6f1a6 JK |
971 | } |
972 | ||
5e161e40 JK |
973 | static int dax_iomap_pfn(struct iomap *iomap, loff_t pos, size_t size, |
974 | pfn_t *pfnp) | |
f7ca90b1 | 975 | { |
31a6f1a6 | 976 | const sector_t sector = dax_iomap_sector(iomap, pos); |
cccbce67 | 977 | pgoff_t pgoff; |
5e161e40 | 978 | void *kaddr; |
cccbce67 | 979 | int id, rc; |
5e161e40 | 980 | long length; |
f7ca90b1 | 981 | |
5e161e40 | 982 | rc = bdev_dax_pgoff(iomap->bdev, sector, size, &pgoff); |
cccbce67 DW |
983 | if (rc) |
984 | return rc; | |
cccbce67 | 985 | id = dax_read_lock(); |
5e161e40 JK |
986 | length = dax_direct_access(iomap->dax_dev, pgoff, PHYS_PFN(size), |
987 | &kaddr, pfnp); | |
988 | if (length < 0) { | |
989 | rc = length; | |
990 | goto out; | |
cccbce67 | 991 | } |
5e161e40 JK |
992 | rc = -EINVAL; |
993 | if (PFN_PHYS(length) < size) | |
994 | goto out; | |
995 | if (pfn_t_to_pfn(*pfnp) & (PHYS_PFN(size)-1)) | |
996 | goto out; | |
997 | /* For larger pages we need devmap */ | |
998 | if (length > 1 && !pfn_t_devmap(*pfnp)) | |
999 | goto out; | |
1000 | rc = 0; | |
1001 | out: | |
cccbce67 | 1002 | dax_read_unlock(id); |
5e161e40 | 1003 | return rc; |
0e3b210c | 1004 | } |
0e3b210c | 1005 | |
e30331ff | 1006 | /* |
91d25ba8 RZ |
1007 | * The user has performed a load from a hole in the file. Allocating a new |
1008 | * page in the file would cause excessive storage usage for workloads with | |
1009 | * sparse files. Instead we insert a read-only mapping of the 4k zero page. | |
1010 | * If this page is ever written to we will re-fault and change the mapping to | |
1011 | * point to real DAX storage instead. | |
e30331ff | 1012 | */ |
ab77dab4 | 1013 | static vm_fault_t dax_load_hole(struct address_space *mapping, void *entry, |
e30331ff RZ |
1014 | struct vm_fault *vmf) |
1015 | { | |
1016 | struct inode *inode = mapping->host; | |
91d25ba8 | 1017 | unsigned long vaddr = vmf->address; |
ab77dab4 | 1018 | vm_fault_t ret = VM_FAULT_NOPAGE; |
91d25ba8 | 1019 | struct page *zero_page; |
3fe0791c | 1020 | pfn_t pfn; |
e30331ff | 1021 | |
91d25ba8 RZ |
1022 | zero_page = ZERO_PAGE(0); |
1023 | if (unlikely(!zero_page)) { | |
e30331ff RZ |
1024 | ret = VM_FAULT_OOM; |
1025 | goto out; | |
1026 | } | |
1027 | ||
3fe0791c | 1028 | pfn = page_to_pfn_t(zero_page); |
cc4a90ac MW |
1029 | dax_insert_mapping_entry(mapping, vmf, entry, pfn, RADIX_DAX_ZERO_PAGE, |
1030 | false); | |
ab77dab4 | 1031 | ret = vmf_insert_mixed(vmf->vma, vaddr, pfn); |
e30331ff RZ |
1032 | out: |
1033 | trace_dax_load_hole(inode, vmf, ret); | |
1034 | return ret; | |
1035 | } | |
1036 | ||
4b0228fa VV |
1037 | static bool dax_range_is_aligned(struct block_device *bdev, |
1038 | unsigned int offset, unsigned int length) | |
1039 | { | |
1040 | unsigned short sector_size = bdev_logical_block_size(bdev); | |
1041 | ||
1042 | if (!IS_ALIGNED(offset, sector_size)) | |
1043 | return false; | |
1044 | if (!IS_ALIGNED(length, sector_size)) | |
1045 | return false; | |
1046 | ||
1047 | return true; | |
1048 | } | |
1049 | ||
cccbce67 DW |
1050 | int __dax_zero_page_range(struct block_device *bdev, |
1051 | struct dax_device *dax_dev, sector_t sector, | |
1052 | unsigned int offset, unsigned int size) | |
679c8bd3 | 1053 | { |
cccbce67 DW |
1054 | if (dax_range_is_aligned(bdev, offset, size)) { |
1055 | sector_t start_sector = sector + (offset >> 9); | |
4b0228fa VV |
1056 | |
1057 | return blkdev_issue_zeroout(bdev, start_sector, | |
53ef7d0e | 1058 | size >> 9, GFP_NOFS, 0); |
4b0228fa | 1059 | } else { |
cccbce67 DW |
1060 | pgoff_t pgoff; |
1061 | long rc, id; | |
1062 | void *kaddr; | |
1063 | pfn_t pfn; | |
1064 | ||
e84b83b9 | 1065 | rc = bdev_dax_pgoff(bdev, sector, PAGE_SIZE, &pgoff); |
cccbce67 DW |
1066 | if (rc) |
1067 | return rc; | |
1068 | ||
1069 | id = dax_read_lock(); | |
e84b83b9 | 1070 | rc = dax_direct_access(dax_dev, pgoff, 1, &kaddr, |
cccbce67 DW |
1071 | &pfn); |
1072 | if (rc < 0) { | |
1073 | dax_read_unlock(id); | |
1074 | return rc; | |
1075 | } | |
81f55870 | 1076 | memset(kaddr + offset, 0, size); |
c3ca015f | 1077 | dax_flush(dax_dev, kaddr + offset, size); |
cccbce67 | 1078 | dax_read_unlock(id); |
4b0228fa | 1079 | } |
679c8bd3 CH |
1080 | return 0; |
1081 | } | |
1082 | EXPORT_SYMBOL_GPL(__dax_zero_page_range); | |
1083 | ||
a254e568 | 1084 | static loff_t |
11c59c92 | 1085 | dax_iomap_actor(struct inode *inode, loff_t pos, loff_t length, void *data, |
a254e568 CH |
1086 | struct iomap *iomap) |
1087 | { | |
cccbce67 DW |
1088 | struct block_device *bdev = iomap->bdev; |
1089 | struct dax_device *dax_dev = iomap->dax_dev; | |
a254e568 CH |
1090 | struct iov_iter *iter = data; |
1091 | loff_t end = pos + length, done = 0; | |
1092 | ssize_t ret = 0; | |
a77d4786 | 1093 | size_t xfer; |
cccbce67 | 1094 | int id; |
a254e568 CH |
1095 | |
1096 | if (iov_iter_rw(iter) == READ) { | |
1097 | end = min(end, i_size_read(inode)); | |
1098 | if (pos >= end) | |
1099 | return 0; | |
1100 | ||
1101 | if (iomap->type == IOMAP_HOLE || iomap->type == IOMAP_UNWRITTEN) | |
1102 | return iov_iter_zero(min(length, end - pos), iter); | |
1103 | } | |
1104 | ||
1105 | if (WARN_ON_ONCE(iomap->type != IOMAP_MAPPED)) | |
1106 | return -EIO; | |
1107 | ||
e3fce68c JK |
1108 | /* |
1109 | * Write can allocate block for an area which has a hole page mapped | |
1110 | * into page tables. We have to tear down these mappings so that data | |
1111 | * written by write(2) is visible in mmap. | |
1112 | */ | |
cd656375 | 1113 | if (iomap->flags & IOMAP_F_NEW) { |
e3fce68c JK |
1114 | invalidate_inode_pages2_range(inode->i_mapping, |
1115 | pos >> PAGE_SHIFT, | |
1116 | (end - 1) >> PAGE_SHIFT); | |
1117 | } | |
1118 | ||
cccbce67 | 1119 | id = dax_read_lock(); |
a254e568 CH |
1120 | while (pos < end) { |
1121 | unsigned offset = pos & (PAGE_SIZE - 1); | |
cccbce67 DW |
1122 | const size_t size = ALIGN(length + offset, PAGE_SIZE); |
1123 | const sector_t sector = dax_iomap_sector(iomap, pos); | |
a254e568 | 1124 | ssize_t map_len; |
cccbce67 DW |
1125 | pgoff_t pgoff; |
1126 | void *kaddr; | |
1127 | pfn_t pfn; | |
a254e568 | 1128 | |
d1908f52 MH |
1129 | if (fatal_signal_pending(current)) { |
1130 | ret = -EINTR; | |
1131 | break; | |
1132 | } | |
1133 | ||
cccbce67 DW |
1134 | ret = bdev_dax_pgoff(bdev, sector, size, &pgoff); |
1135 | if (ret) | |
1136 | break; | |
1137 | ||
1138 | map_len = dax_direct_access(dax_dev, pgoff, PHYS_PFN(size), | |
1139 | &kaddr, &pfn); | |
a254e568 CH |
1140 | if (map_len < 0) { |
1141 | ret = map_len; | |
1142 | break; | |
1143 | } | |
1144 | ||
cccbce67 DW |
1145 | map_len = PFN_PHYS(map_len); |
1146 | kaddr += offset; | |
a254e568 CH |
1147 | map_len -= offset; |
1148 | if (map_len > end - pos) | |
1149 | map_len = end - pos; | |
1150 | ||
a2e050f5 RZ |
1151 | /* |
1152 | * The userspace address for the memory copy has already been | |
1153 | * validated via access_ok() in either vfs_read() or | |
1154 | * vfs_write(), depending on which operation we are doing. | |
1155 | */ | |
a254e568 | 1156 | if (iov_iter_rw(iter) == WRITE) |
a77d4786 | 1157 | xfer = dax_copy_from_iter(dax_dev, pgoff, kaddr, |
fec53774 | 1158 | map_len, iter); |
a254e568 | 1159 | else |
a77d4786 | 1160 | xfer = dax_copy_to_iter(dax_dev, pgoff, kaddr, |
b3a9a0c3 | 1161 | map_len, iter); |
a254e568 | 1162 | |
a77d4786 DW |
1163 | pos += xfer; |
1164 | length -= xfer; | |
1165 | done += xfer; | |
1166 | ||
1167 | if (xfer == 0) | |
1168 | ret = -EFAULT; | |
1169 | if (xfer < map_len) | |
1170 | break; | |
a254e568 | 1171 | } |
cccbce67 | 1172 | dax_read_unlock(id); |
a254e568 CH |
1173 | |
1174 | return done ? done : ret; | |
1175 | } | |
1176 | ||
1177 | /** | |
11c59c92 | 1178 | * dax_iomap_rw - Perform I/O to a DAX file |
a254e568 CH |
1179 | * @iocb: The control block for this I/O |
1180 | * @iter: The addresses to do I/O from or to | |
1181 | * @ops: iomap ops passed from the file system | |
1182 | * | |
1183 | * This function performs read and write operations to directly mapped | |
1184 | * persistent memory. The callers needs to take care of read/write exclusion | |
1185 | * and evicting any page cache pages in the region under I/O. | |
1186 | */ | |
1187 | ssize_t | |
11c59c92 | 1188 | dax_iomap_rw(struct kiocb *iocb, struct iov_iter *iter, |
8ff6daa1 | 1189 | const struct iomap_ops *ops) |
a254e568 CH |
1190 | { |
1191 | struct address_space *mapping = iocb->ki_filp->f_mapping; | |
1192 | struct inode *inode = mapping->host; | |
1193 | loff_t pos = iocb->ki_pos, ret = 0, done = 0; | |
1194 | unsigned flags = 0; | |
1195 | ||
168316db CH |
1196 | if (iov_iter_rw(iter) == WRITE) { |
1197 | lockdep_assert_held_exclusive(&inode->i_rwsem); | |
a254e568 | 1198 | flags |= IOMAP_WRITE; |
168316db CH |
1199 | } else { |
1200 | lockdep_assert_held(&inode->i_rwsem); | |
1201 | } | |
a254e568 | 1202 | |
a254e568 CH |
1203 | while (iov_iter_count(iter)) { |
1204 | ret = iomap_apply(inode, pos, iov_iter_count(iter), flags, ops, | |
11c59c92 | 1205 | iter, dax_iomap_actor); |
a254e568 CH |
1206 | if (ret <= 0) |
1207 | break; | |
1208 | pos += ret; | |
1209 | done += ret; | |
1210 | } | |
1211 | ||
1212 | iocb->ki_pos += done; | |
1213 | return done ? done : ret; | |
1214 | } | |
11c59c92 | 1215 | EXPORT_SYMBOL_GPL(dax_iomap_rw); |
a7d73fe6 | 1216 | |
ab77dab4 | 1217 | static vm_fault_t dax_fault_return(int error) |
9f141d6e JK |
1218 | { |
1219 | if (error == 0) | |
1220 | return VM_FAULT_NOPAGE; | |
1221 | if (error == -ENOMEM) | |
1222 | return VM_FAULT_OOM; | |
1223 | return VM_FAULT_SIGBUS; | |
1224 | } | |
1225 | ||
aaa422c4 DW |
1226 | /* |
1227 | * MAP_SYNC on a dax mapping guarantees dirty metadata is | |
1228 | * flushed on write-faults (non-cow), but not read-faults. | |
1229 | */ | |
1230 | static bool dax_fault_is_synchronous(unsigned long flags, | |
1231 | struct vm_area_struct *vma, struct iomap *iomap) | |
1232 | { | |
1233 | return (flags & IOMAP_WRITE) && (vma->vm_flags & VM_SYNC) | |
1234 | && (iomap->flags & IOMAP_F_DIRTY); | |
1235 | } | |
1236 | ||
ab77dab4 | 1237 | static vm_fault_t dax_iomap_pte_fault(struct vm_fault *vmf, pfn_t *pfnp, |
c0b24625 | 1238 | int *iomap_errp, const struct iomap_ops *ops) |
a7d73fe6 | 1239 | { |
a0987ad5 JK |
1240 | struct vm_area_struct *vma = vmf->vma; |
1241 | struct address_space *mapping = vma->vm_file->f_mapping; | |
a7d73fe6 | 1242 | struct inode *inode = mapping->host; |
1a29d85e | 1243 | unsigned long vaddr = vmf->address; |
a7d73fe6 | 1244 | loff_t pos = (loff_t)vmf->pgoff << PAGE_SHIFT; |
a7d73fe6 | 1245 | struct iomap iomap = { 0 }; |
9484ab1b | 1246 | unsigned flags = IOMAP_FAULT; |
a7d73fe6 | 1247 | int error, major = 0; |
d2c43ef1 | 1248 | bool write = vmf->flags & FAULT_FLAG_WRITE; |
caa51d26 | 1249 | bool sync; |
ab77dab4 | 1250 | vm_fault_t ret = 0; |
a7d73fe6 | 1251 | void *entry; |
1b5a1cb2 | 1252 | pfn_t pfn; |
a7d73fe6 | 1253 | |
ab77dab4 | 1254 | trace_dax_pte_fault(inode, vmf, ret); |
a7d73fe6 CH |
1255 | /* |
1256 | * Check whether offset isn't beyond end of file now. Caller is supposed | |
1257 | * to hold locks serializing us with truncate / punch hole so this is | |
1258 | * a reliable test. | |
1259 | */ | |
a9c42b33 | 1260 | if (pos >= i_size_read(inode)) { |
ab77dab4 | 1261 | ret = VM_FAULT_SIGBUS; |
a9c42b33 RZ |
1262 | goto out; |
1263 | } | |
a7d73fe6 | 1264 | |
d2c43ef1 | 1265 | if (write && !vmf->cow_page) |
a7d73fe6 CH |
1266 | flags |= IOMAP_WRITE; |
1267 | ||
13e451fd JK |
1268 | entry = grab_mapping_entry(mapping, vmf->pgoff, 0); |
1269 | if (IS_ERR(entry)) { | |
ab77dab4 | 1270 | ret = dax_fault_return(PTR_ERR(entry)); |
13e451fd JK |
1271 | goto out; |
1272 | } | |
1273 | ||
e2093926 RZ |
1274 | /* |
1275 | * It is possible, particularly with mixed reads & writes to private | |
1276 | * mappings, that we have raced with a PMD fault that overlaps with | |
1277 | * the PTE we need to set up. If so just return and the fault will be | |
1278 | * retried. | |
1279 | */ | |
1280 | if (pmd_trans_huge(*vmf->pmd) || pmd_devmap(*vmf->pmd)) { | |
ab77dab4 | 1281 | ret = VM_FAULT_NOPAGE; |
e2093926 RZ |
1282 | goto unlock_entry; |
1283 | } | |
1284 | ||
a7d73fe6 CH |
1285 | /* |
1286 | * Note that we don't bother to use iomap_apply here: DAX required | |
1287 | * the file system block size to be equal the page size, which means | |
1288 | * that we never have to deal with more than a single extent here. | |
1289 | */ | |
1290 | error = ops->iomap_begin(inode, pos, PAGE_SIZE, flags, &iomap); | |
c0b24625 JK |
1291 | if (iomap_errp) |
1292 | *iomap_errp = error; | |
a9c42b33 | 1293 | if (error) { |
ab77dab4 | 1294 | ret = dax_fault_return(error); |
13e451fd | 1295 | goto unlock_entry; |
a9c42b33 | 1296 | } |
a7d73fe6 | 1297 | if (WARN_ON_ONCE(iomap.offset + iomap.length < pos + PAGE_SIZE)) { |
13e451fd JK |
1298 | error = -EIO; /* fs corruption? */ |
1299 | goto error_finish_iomap; | |
a7d73fe6 CH |
1300 | } |
1301 | ||
a7d73fe6 | 1302 | if (vmf->cow_page) { |
31a6f1a6 JK |
1303 | sector_t sector = dax_iomap_sector(&iomap, pos); |
1304 | ||
a7d73fe6 CH |
1305 | switch (iomap.type) { |
1306 | case IOMAP_HOLE: | |
1307 | case IOMAP_UNWRITTEN: | |
1308 | clear_user_highpage(vmf->cow_page, vaddr); | |
1309 | break; | |
1310 | case IOMAP_MAPPED: | |
cccbce67 DW |
1311 | error = copy_user_dax(iomap.bdev, iomap.dax_dev, |
1312 | sector, PAGE_SIZE, vmf->cow_page, vaddr); | |
a7d73fe6 CH |
1313 | break; |
1314 | default: | |
1315 | WARN_ON_ONCE(1); | |
1316 | error = -EIO; | |
1317 | break; | |
1318 | } | |
1319 | ||
1320 | if (error) | |
13e451fd | 1321 | goto error_finish_iomap; |
b1aa812b JK |
1322 | |
1323 | __SetPageUptodate(vmf->cow_page); | |
ab77dab4 SJ |
1324 | ret = finish_fault(vmf); |
1325 | if (!ret) | |
1326 | ret = VM_FAULT_DONE_COW; | |
13e451fd | 1327 | goto finish_iomap; |
a7d73fe6 CH |
1328 | } |
1329 | ||
aaa422c4 | 1330 | sync = dax_fault_is_synchronous(flags, vma, &iomap); |
caa51d26 | 1331 | |
a7d73fe6 CH |
1332 | switch (iomap.type) { |
1333 | case IOMAP_MAPPED: | |
1334 | if (iomap.flags & IOMAP_F_NEW) { | |
1335 | count_vm_event(PGMAJFAULT); | |
a0987ad5 | 1336 | count_memcg_event_mm(vma->vm_mm, PGMAJFAULT); |
a7d73fe6 CH |
1337 | major = VM_FAULT_MAJOR; |
1338 | } | |
1b5a1cb2 JK |
1339 | error = dax_iomap_pfn(&iomap, pos, PAGE_SIZE, &pfn); |
1340 | if (error < 0) | |
1341 | goto error_finish_iomap; | |
1342 | ||
3fe0791c | 1343 | entry = dax_insert_mapping_entry(mapping, vmf, entry, pfn, |
caa51d26 | 1344 | 0, write && !sync); |
1b5a1cb2 | 1345 | |
caa51d26 JK |
1346 | /* |
1347 | * If we are doing synchronous page fault and inode needs fsync, | |
1348 | * we can insert PTE into page tables only after that happens. | |
1349 | * Skip insertion for now and return the pfn so that caller can | |
1350 | * insert it after fsync is done. | |
1351 | */ | |
1352 | if (sync) { | |
1353 | if (WARN_ON_ONCE(!pfnp)) { | |
1354 | error = -EIO; | |
1355 | goto error_finish_iomap; | |
1356 | } | |
1357 | *pfnp = pfn; | |
ab77dab4 | 1358 | ret = VM_FAULT_NEEDDSYNC | major; |
caa51d26 JK |
1359 | goto finish_iomap; |
1360 | } | |
1b5a1cb2 JK |
1361 | trace_dax_insert_mapping(inode, vmf, entry); |
1362 | if (write) | |
ab77dab4 | 1363 | ret = vmf_insert_mixed_mkwrite(vma, vaddr, pfn); |
1b5a1cb2 | 1364 | else |
ab77dab4 | 1365 | ret = vmf_insert_mixed(vma, vaddr, pfn); |
1b5a1cb2 | 1366 | |
ab77dab4 | 1367 | goto finish_iomap; |
a7d73fe6 CH |
1368 | case IOMAP_UNWRITTEN: |
1369 | case IOMAP_HOLE: | |
d2c43ef1 | 1370 | if (!write) { |
ab77dab4 | 1371 | ret = dax_load_hole(mapping, entry, vmf); |
13e451fd | 1372 | goto finish_iomap; |
1550290b | 1373 | } |
a7d73fe6 CH |
1374 | /*FALLTHRU*/ |
1375 | default: | |
1376 | WARN_ON_ONCE(1); | |
1377 | error = -EIO; | |
1378 | break; | |
1379 | } | |
1380 | ||
13e451fd | 1381 | error_finish_iomap: |
ab77dab4 | 1382 | ret = dax_fault_return(error); |
9f141d6e JK |
1383 | finish_iomap: |
1384 | if (ops->iomap_end) { | |
1385 | int copied = PAGE_SIZE; | |
1386 | ||
ab77dab4 | 1387 | if (ret & VM_FAULT_ERROR) |
9f141d6e JK |
1388 | copied = 0; |
1389 | /* | |
1390 | * The fault is done by now and there's no way back (other | |
1391 | * thread may be already happily using PTE we have installed). | |
1392 | * Just ignore error from ->iomap_end since we cannot do much | |
1393 | * with it. | |
1394 | */ | |
1395 | ops->iomap_end(inode, pos, PAGE_SIZE, copied, flags, &iomap); | |
1550290b | 1396 | } |
13e451fd | 1397 | unlock_entry: |
91d25ba8 | 1398 | put_locked_mapping_entry(mapping, vmf->pgoff); |
13e451fd | 1399 | out: |
ab77dab4 SJ |
1400 | trace_dax_pte_fault_done(inode, vmf, ret); |
1401 | return ret | major; | |
a7d73fe6 | 1402 | } |
642261ac RZ |
1403 | |
1404 | #ifdef CONFIG_FS_DAX_PMD | |
ab77dab4 | 1405 | static vm_fault_t dax_pmd_load_hole(struct vm_fault *vmf, struct iomap *iomap, |
91d25ba8 | 1406 | void *entry) |
642261ac | 1407 | { |
f4200391 DJ |
1408 | struct address_space *mapping = vmf->vma->vm_file->f_mapping; |
1409 | unsigned long pmd_addr = vmf->address & PMD_MASK; | |
653b2ea3 | 1410 | struct inode *inode = mapping->host; |
642261ac | 1411 | struct page *zero_page; |
653b2ea3 | 1412 | void *ret = NULL; |
642261ac RZ |
1413 | spinlock_t *ptl; |
1414 | pmd_t pmd_entry; | |
3fe0791c | 1415 | pfn_t pfn; |
642261ac | 1416 | |
f4200391 | 1417 | zero_page = mm_get_huge_zero_page(vmf->vma->vm_mm); |
642261ac RZ |
1418 | |
1419 | if (unlikely(!zero_page)) | |
653b2ea3 | 1420 | goto fallback; |
642261ac | 1421 | |
3fe0791c DW |
1422 | pfn = page_to_pfn_t(zero_page); |
1423 | ret = dax_insert_mapping_entry(mapping, vmf, entry, pfn, | |
f5b7b748 | 1424 | RADIX_DAX_PMD | RADIX_DAX_ZERO_PAGE, false); |
642261ac | 1425 | |
f4200391 DJ |
1426 | ptl = pmd_lock(vmf->vma->vm_mm, vmf->pmd); |
1427 | if (!pmd_none(*(vmf->pmd))) { | |
642261ac | 1428 | spin_unlock(ptl); |
653b2ea3 | 1429 | goto fallback; |
642261ac RZ |
1430 | } |
1431 | ||
f4200391 | 1432 | pmd_entry = mk_pmd(zero_page, vmf->vma->vm_page_prot); |
642261ac | 1433 | pmd_entry = pmd_mkhuge(pmd_entry); |
f4200391 | 1434 | set_pmd_at(vmf->vma->vm_mm, pmd_addr, vmf->pmd, pmd_entry); |
642261ac | 1435 | spin_unlock(ptl); |
f4200391 | 1436 | trace_dax_pmd_load_hole(inode, vmf, zero_page, ret); |
642261ac | 1437 | return VM_FAULT_NOPAGE; |
653b2ea3 RZ |
1438 | |
1439 | fallback: | |
f4200391 | 1440 | trace_dax_pmd_load_hole_fallback(inode, vmf, zero_page, ret); |
653b2ea3 | 1441 | return VM_FAULT_FALLBACK; |
642261ac RZ |
1442 | } |
1443 | ||
ab77dab4 | 1444 | static vm_fault_t dax_iomap_pmd_fault(struct vm_fault *vmf, pfn_t *pfnp, |
a2d58167 | 1445 | const struct iomap_ops *ops) |
642261ac | 1446 | { |
f4200391 | 1447 | struct vm_area_struct *vma = vmf->vma; |
642261ac | 1448 | struct address_space *mapping = vma->vm_file->f_mapping; |
d8a849e1 DJ |
1449 | unsigned long pmd_addr = vmf->address & PMD_MASK; |
1450 | bool write = vmf->flags & FAULT_FLAG_WRITE; | |
caa51d26 | 1451 | bool sync; |
9484ab1b | 1452 | unsigned int iomap_flags = (write ? IOMAP_WRITE : 0) | IOMAP_FAULT; |
642261ac | 1453 | struct inode *inode = mapping->host; |
ab77dab4 | 1454 | vm_fault_t result = VM_FAULT_FALLBACK; |
642261ac RZ |
1455 | struct iomap iomap = { 0 }; |
1456 | pgoff_t max_pgoff, pgoff; | |
642261ac RZ |
1457 | void *entry; |
1458 | loff_t pos; | |
1459 | int error; | |
302a5e31 | 1460 | pfn_t pfn; |
642261ac | 1461 | |
282a8e03 RZ |
1462 | /* |
1463 | * Check whether offset isn't beyond end of file now. Caller is | |
1464 | * supposed to hold locks serializing us with truncate / punch hole so | |
1465 | * this is a reliable test. | |
1466 | */ | |
1467 | pgoff = linear_page_index(vma, pmd_addr); | |
957ac8c4 | 1468 | max_pgoff = DIV_ROUND_UP(i_size_read(inode), PAGE_SIZE); |
282a8e03 | 1469 | |
f4200391 | 1470 | trace_dax_pmd_fault(inode, vmf, max_pgoff, 0); |
282a8e03 | 1471 | |
fffa281b RZ |
1472 | /* |
1473 | * Make sure that the faulting address's PMD offset (color) matches | |
1474 | * the PMD offset from the start of the file. This is necessary so | |
1475 | * that a PMD range in the page table overlaps exactly with a PMD | |
1476 | * range in the radix tree. | |
1477 | */ | |
1478 | if ((vmf->pgoff & PG_PMD_COLOUR) != | |
1479 | ((vmf->address >> PAGE_SHIFT) & PG_PMD_COLOUR)) | |
1480 | goto fallback; | |
1481 | ||
642261ac RZ |
1482 | /* Fall back to PTEs if we're going to COW */ |
1483 | if (write && !(vma->vm_flags & VM_SHARED)) | |
1484 | goto fallback; | |
1485 | ||
1486 | /* If the PMD would extend outside the VMA */ | |
1487 | if (pmd_addr < vma->vm_start) | |
1488 | goto fallback; | |
1489 | if ((pmd_addr + PMD_SIZE) > vma->vm_end) | |
1490 | goto fallback; | |
1491 | ||
957ac8c4 | 1492 | if (pgoff >= max_pgoff) { |
282a8e03 RZ |
1493 | result = VM_FAULT_SIGBUS; |
1494 | goto out; | |
1495 | } | |
642261ac RZ |
1496 | |
1497 | /* If the PMD would extend beyond the file size */ | |
957ac8c4 | 1498 | if ((pgoff | PG_PMD_COLOUR) >= max_pgoff) |
642261ac RZ |
1499 | goto fallback; |
1500 | ||
876f2946 | 1501 | /* |
91d25ba8 RZ |
1502 | * grab_mapping_entry() will make sure we get a 2MiB empty entry, a |
1503 | * 2MiB zero page entry or a DAX PMD. If it can't (because a 4k page | |
1504 | * is already in the tree, for instance), it will return -EEXIST and | |
1505 | * we just fall back to 4k entries. | |
876f2946 RZ |
1506 | */ |
1507 | entry = grab_mapping_entry(mapping, pgoff, RADIX_DAX_PMD); | |
1508 | if (IS_ERR(entry)) | |
1509 | goto fallback; | |
1510 | ||
e2093926 RZ |
1511 | /* |
1512 | * It is possible, particularly with mixed reads & writes to private | |
1513 | * mappings, that we have raced with a PTE fault that overlaps with | |
1514 | * the PMD we need to set up. If so just return and the fault will be | |
1515 | * retried. | |
1516 | */ | |
1517 | if (!pmd_none(*vmf->pmd) && !pmd_trans_huge(*vmf->pmd) && | |
1518 | !pmd_devmap(*vmf->pmd)) { | |
1519 | result = 0; | |
1520 | goto unlock_entry; | |
1521 | } | |
1522 | ||
642261ac RZ |
1523 | /* |
1524 | * Note that we don't use iomap_apply here. We aren't doing I/O, only | |
1525 | * setting up a mapping, so really we're using iomap_begin() as a way | |
1526 | * to look up our filesystem block. | |
1527 | */ | |
1528 | pos = (loff_t)pgoff << PAGE_SHIFT; | |
1529 | error = ops->iomap_begin(inode, pos, PMD_SIZE, iomap_flags, &iomap); | |
1530 | if (error) | |
876f2946 | 1531 | goto unlock_entry; |
9f141d6e | 1532 | |
642261ac RZ |
1533 | if (iomap.offset + iomap.length < pos + PMD_SIZE) |
1534 | goto finish_iomap; | |
1535 | ||
aaa422c4 | 1536 | sync = dax_fault_is_synchronous(iomap_flags, vma, &iomap); |
caa51d26 | 1537 | |
642261ac RZ |
1538 | switch (iomap.type) { |
1539 | case IOMAP_MAPPED: | |
302a5e31 JK |
1540 | error = dax_iomap_pfn(&iomap, pos, PMD_SIZE, &pfn); |
1541 | if (error < 0) | |
1542 | goto finish_iomap; | |
1543 | ||
3fe0791c | 1544 | entry = dax_insert_mapping_entry(mapping, vmf, entry, pfn, |
caa51d26 | 1545 | RADIX_DAX_PMD, write && !sync); |
302a5e31 | 1546 | |
caa51d26 JK |
1547 | /* |
1548 | * If we are doing synchronous page fault and inode needs fsync, | |
1549 | * we can insert PMD into page tables only after that happens. | |
1550 | * Skip insertion for now and return the pfn so that caller can | |
1551 | * insert it after fsync is done. | |
1552 | */ | |
1553 | if (sync) { | |
1554 | if (WARN_ON_ONCE(!pfnp)) | |
1555 | goto finish_iomap; | |
1556 | *pfnp = pfn; | |
1557 | result = VM_FAULT_NEEDDSYNC; | |
1558 | goto finish_iomap; | |
1559 | } | |
1560 | ||
302a5e31 JK |
1561 | trace_dax_pmd_insert_mapping(inode, vmf, PMD_SIZE, pfn, entry); |
1562 | result = vmf_insert_pfn_pmd(vma, vmf->address, vmf->pmd, pfn, | |
1563 | write); | |
642261ac RZ |
1564 | break; |
1565 | case IOMAP_UNWRITTEN: | |
1566 | case IOMAP_HOLE: | |
1567 | if (WARN_ON_ONCE(write)) | |
876f2946 | 1568 | break; |
91d25ba8 | 1569 | result = dax_pmd_load_hole(vmf, &iomap, entry); |
642261ac RZ |
1570 | break; |
1571 | default: | |
1572 | WARN_ON_ONCE(1); | |
1573 | break; | |
1574 | } | |
1575 | ||
1576 | finish_iomap: | |
1577 | if (ops->iomap_end) { | |
9f141d6e JK |
1578 | int copied = PMD_SIZE; |
1579 | ||
1580 | if (result == VM_FAULT_FALLBACK) | |
1581 | copied = 0; | |
1582 | /* | |
1583 | * The fault is done by now and there's no way back (other | |
1584 | * thread may be already happily using PMD we have installed). | |
1585 | * Just ignore error from ->iomap_end since we cannot do much | |
1586 | * with it. | |
1587 | */ | |
1588 | ops->iomap_end(inode, pos, PMD_SIZE, copied, iomap_flags, | |
1589 | &iomap); | |
642261ac | 1590 | } |
876f2946 | 1591 | unlock_entry: |
91d25ba8 | 1592 | put_locked_mapping_entry(mapping, pgoff); |
642261ac RZ |
1593 | fallback: |
1594 | if (result == VM_FAULT_FALLBACK) { | |
d8a849e1 | 1595 | split_huge_pmd(vma, vmf->pmd, vmf->address); |
642261ac RZ |
1596 | count_vm_event(THP_FAULT_FALLBACK); |
1597 | } | |
282a8e03 | 1598 | out: |
f4200391 | 1599 | trace_dax_pmd_fault_done(inode, vmf, max_pgoff, result); |
642261ac RZ |
1600 | return result; |
1601 | } | |
a2d58167 | 1602 | #else |
ab77dab4 | 1603 | static vm_fault_t dax_iomap_pmd_fault(struct vm_fault *vmf, pfn_t *pfnp, |
01cddfe9 | 1604 | const struct iomap_ops *ops) |
a2d58167 DJ |
1605 | { |
1606 | return VM_FAULT_FALLBACK; | |
1607 | } | |
642261ac | 1608 | #endif /* CONFIG_FS_DAX_PMD */ |
a2d58167 DJ |
1609 | |
1610 | /** | |
1611 | * dax_iomap_fault - handle a page fault on a DAX file | |
1612 | * @vmf: The description of the fault | |
cec04e8c | 1613 | * @pe_size: Size of the page to fault in |
9a0dd422 | 1614 | * @pfnp: PFN to insert for synchronous faults if fsync is required |
c0b24625 | 1615 | * @iomap_errp: Storage for detailed error code in case of error |
cec04e8c | 1616 | * @ops: Iomap ops passed from the file system |
a2d58167 DJ |
1617 | * |
1618 | * When a page fault occurs, filesystems may call this helper in | |
1619 | * their fault handler for DAX files. dax_iomap_fault() assumes the caller | |
1620 | * has done all the necessary locking for page fault to proceed | |
1621 | * successfully. | |
1622 | */ | |
ab77dab4 | 1623 | vm_fault_t dax_iomap_fault(struct vm_fault *vmf, enum page_entry_size pe_size, |
c0b24625 | 1624 | pfn_t *pfnp, int *iomap_errp, const struct iomap_ops *ops) |
a2d58167 | 1625 | { |
c791ace1 DJ |
1626 | switch (pe_size) { |
1627 | case PE_SIZE_PTE: | |
c0b24625 | 1628 | return dax_iomap_pte_fault(vmf, pfnp, iomap_errp, ops); |
c791ace1 | 1629 | case PE_SIZE_PMD: |
9a0dd422 | 1630 | return dax_iomap_pmd_fault(vmf, pfnp, ops); |
a2d58167 DJ |
1631 | default: |
1632 | return VM_FAULT_FALLBACK; | |
1633 | } | |
1634 | } | |
1635 | EXPORT_SYMBOL_GPL(dax_iomap_fault); | |
71eab6df JK |
1636 | |
1637 | /** | |
1638 | * dax_insert_pfn_mkwrite - insert PTE or PMD entry into page tables | |
1639 | * @vmf: The description of the fault | |
1640 | * @pe_size: Size of entry to be inserted | |
1641 | * @pfn: PFN to insert | |
1642 | * | |
1643 | * This function inserts writeable PTE or PMD entry into page tables for mmaped | |
1644 | * DAX file. It takes care of marking corresponding radix tree entry as dirty | |
1645 | * as well. | |
1646 | */ | |
ab77dab4 | 1647 | static vm_fault_t dax_insert_pfn_mkwrite(struct vm_fault *vmf, |
71eab6df JK |
1648 | enum page_entry_size pe_size, |
1649 | pfn_t pfn) | |
1650 | { | |
1651 | struct address_space *mapping = vmf->vma->vm_file->f_mapping; | |
1652 | void *entry, **slot; | |
1653 | pgoff_t index = vmf->pgoff; | |
ab77dab4 | 1654 | vm_fault_t ret; |
71eab6df | 1655 | |
b93b0163 | 1656 | xa_lock_irq(&mapping->i_pages); |
71eab6df JK |
1657 | entry = get_unlocked_mapping_entry(mapping, index, &slot); |
1658 | /* Did we race with someone splitting entry or so? */ | |
1659 | if (!entry || | |
1660 | (pe_size == PE_SIZE_PTE && !dax_is_pte_entry(entry)) || | |
1661 | (pe_size == PE_SIZE_PMD && !dax_is_pmd_entry(entry))) { | |
1662 | put_unlocked_mapping_entry(mapping, index, entry); | |
b93b0163 | 1663 | xa_unlock_irq(&mapping->i_pages); |
71eab6df JK |
1664 | trace_dax_insert_pfn_mkwrite_no_entry(mapping->host, vmf, |
1665 | VM_FAULT_NOPAGE); | |
1666 | return VM_FAULT_NOPAGE; | |
1667 | } | |
b93b0163 | 1668 | radix_tree_tag_set(&mapping->i_pages, index, PAGECACHE_TAG_DIRTY); |
71eab6df | 1669 | entry = lock_slot(mapping, slot); |
b93b0163 | 1670 | xa_unlock_irq(&mapping->i_pages); |
71eab6df JK |
1671 | switch (pe_size) { |
1672 | case PE_SIZE_PTE: | |
ab77dab4 | 1673 | ret = vmf_insert_mixed_mkwrite(vmf->vma, vmf->address, pfn); |
71eab6df JK |
1674 | break; |
1675 | #ifdef CONFIG_FS_DAX_PMD | |
1676 | case PE_SIZE_PMD: | |
ab77dab4 | 1677 | ret = vmf_insert_pfn_pmd(vmf->vma, vmf->address, vmf->pmd, |
71eab6df JK |
1678 | pfn, true); |
1679 | break; | |
1680 | #endif | |
1681 | default: | |
ab77dab4 | 1682 | ret = VM_FAULT_FALLBACK; |
71eab6df JK |
1683 | } |
1684 | put_locked_mapping_entry(mapping, index); | |
ab77dab4 SJ |
1685 | trace_dax_insert_pfn_mkwrite(mapping->host, vmf, ret); |
1686 | return ret; | |
71eab6df JK |
1687 | } |
1688 | ||
1689 | /** | |
1690 | * dax_finish_sync_fault - finish synchronous page fault | |
1691 | * @vmf: The description of the fault | |
1692 | * @pe_size: Size of entry to be inserted | |
1693 | * @pfn: PFN to insert | |
1694 | * | |
1695 | * This function ensures that the file range touched by the page fault is | |
1696 | * stored persistently on the media and handles inserting of appropriate page | |
1697 | * table entry. | |
1698 | */ | |
ab77dab4 SJ |
1699 | vm_fault_t dax_finish_sync_fault(struct vm_fault *vmf, |
1700 | enum page_entry_size pe_size, pfn_t pfn) | |
71eab6df JK |
1701 | { |
1702 | int err; | |
1703 | loff_t start = ((loff_t)vmf->pgoff) << PAGE_SHIFT; | |
1704 | size_t len = 0; | |
1705 | ||
1706 | if (pe_size == PE_SIZE_PTE) | |
1707 | len = PAGE_SIZE; | |
1708 | else if (pe_size == PE_SIZE_PMD) | |
1709 | len = PMD_SIZE; | |
1710 | else | |
1711 | WARN_ON_ONCE(1); | |
1712 | err = vfs_fsync_range(vmf->vma->vm_file, start, start + len - 1, 1); | |
1713 | if (err) | |
1714 | return VM_FAULT_SIGBUS; | |
1715 | return dax_insert_pfn_mkwrite(vmf, pe_size, pfn); | |
1716 | } | |
1717 | EXPORT_SYMBOL_GPL(dax_finish_sync_fault); |