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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 | ||
ce95ab0f | 45 | static wait_queue_head_t wait_table[DAX_WAIT_TABLE_ENTRIES]; |
ac401cc7 JK |
46 | |
47 | static int __init init_dax_wait_table(void) | |
48 | { | |
49 | int i; | |
50 | ||
51 | for (i = 0; i < DAX_WAIT_TABLE_ENTRIES; i++) | |
52 | init_waitqueue_head(wait_table + i); | |
53 | return 0; | |
54 | } | |
55 | fs_initcall(init_dax_wait_table); | |
56 | ||
642261ac | 57 | static int dax_is_pmd_entry(void *entry) |
d1a5f2b4 | 58 | { |
642261ac | 59 | return (unsigned long)entry & RADIX_DAX_PMD; |
d1a5f2b4 DW |
60 | } |
61 | ||
642261ac | 62 | static int dax_is_pte_entry(void *entry) |
d475c634 | 63 | { |
642261ac | 64 | return !((unsigned long)entry & RADIX_DAX_PMD); |
d475c634 MW |
65 | } |
66 | ||
642261ac | 67 | static int dax_is_zero_entry(void *entry) |
d475c634 | 68 | { |
642261ac | 69 | return (unsigned long)entry & RADIX_DAX_HZP; |
d475c634 MW |
70 | } |
71 | ||
642261ac | 72 | static int dax_is_empty_entry(void *entry) |
b2e0d162 | 73 | { |
642261ac | 74 | return (unsigned long)entry & RADIX_DAX_EMPTY; |
b2e0d162 DW |
75 | } |
76 | ||
ac401cc7 JK |
77 | /* |
78 | * DAX radix tree locking | |
79 | */ | |
80 | struct exceptional_entry_key { | |
81 | struct address_space *mapping; | |
63e95b5c | 82 | pgoff_t entry_start; |
ac401cc7 JK |
83 | }; |
84 | ||
85 | struct wait_exceptional_entry_queue { | |
ac6424b9 | 86 | wait_queue_entry_t wait; |
ac401cc7 JK |
87 | struct exceptional_entry_key key; |
88 | }; | |
89 | ||
63e95b5c RZ |
90 | static wait_queue_head_t *dax_entry_waitqueue(struct address_space *mapping, |
91 | pgoff_t index, void *entry, struct exceptional_entry_key *key) | |
92 | { | |
93 | unsigned long hash; | |
94 | ||
95 | /* | |
96 | * If 'entry' is a PMD, align the 'index' that we use for the wait | |
97 | * queue to the start of that PMD. This ensures that all offsets in | |
98 | * the range covered by the PMD map to the same bit lock. | |
99 | */ | |
642261ac | 100 | if (dax_is_pmd_entry(entry)) |
63e95b5c RZ |
101 | index &= ~((1UL << (PMD_SHIFT - PAGE_SHIFT)) - 1); |
102 | ||
103 | key->mapping = mapping; | |
104 | key->entry_start = index; | |
105 | ||
106 | hash = hash_long((unsigned long)mapping ^ index, DAX_WAIT_TABLE_BITS); | |
107 | return wait_table + hash; | |
108 | } | |
109 | ||
ac6424b9 | 110 | static int wake_exceptional_entry_func(wait_queue_entry_t *wait, unsigned int mode, |
ac401cc7 JK |
111 | int sync, void *keyp) |
112 | { | |
113 | struct exceptional_entry_key *key = keyp; | |
114 | struct wait_exceptional_entry_queue *ewait = | |
115 | container_of(wait, struct wait_exceptional_entry_queue, wait); | |
116 | ||
117 | if (key->mapping != ewait->key.mapping || | |
63e95b5c | 118 | key->entry_start != ewait->key.entry_start) |
ac401cc7 JK |
119 | return 0; |
120 | return autoremove_wake_function(wait, mode, sync, NULL); | |
121 | } | |
122 | ||
123 | /* | |
124 | * Check whether the given slot is locked. The function must be called with | |
125 | * mapping->tree_lock held | |
126 | */ | |
127 | static inline int slot_locked(struct address_space *mapping, void **slot) | |
128 | { | |
129 | unsigned long entry = (unsigned long) | |
130 | radix_tree_deref_slot_protected(slot, &mapping->tree_lock); | |
131 | return entry & RADIX_DAX_ENTRY_LOCK; | |
132 | } | |
133 | ||
134 | /* | |
135 | * Mark the given slot is locked. The function must be called with | |
136 | * mapping->tree_lock held | |
137 | */ | |
138 | static inline void *lock_slot(struct address_space *mapping, void **slot) | |
139 | { | |
140 | unsigned long entry = (unsigned long) | |
141 | radix_tree_deref_slot_protected(slot, &mapping->tree_lock); | |
142 | ||
143 | entry |= RADIX_DAX_ENTRY_LOCK; | |
6d75f366 | 144 | radix_tree_replace_slot(&mapping->page_tree, slot, (void *)entry); |
ac401cc7 JK |
145 | return (void *)entry; |
146 | } | |
147 | ||
148 | /* | |
149 | * Mark the given slot is unlocked. The function must be called with | |
150 | * mapping->tree_lock held | |
151 | */ | |
152 | static inline void *unlock_slot(struct address_space *mapping, void **slot) | |
153 | { | |
154 | unsigned long entry = (unsigned long) | |
155 | radix_tree_deref_slot_protected(slot, &mapping->tree_lock); | |
156 | ||
157 | entry &= ~(unsigned long)RADIX_DAX_ENTRY_LOCK; | |
6d75f366 | 158 | radix_tree_replace_slot(&mapping->page_tree, slot, (void *)entry); |
ac401cc7 JK |
159 | return (void *)entry; |
160 | } | |
161 | ||
162 | /* | |
163 | * Lookup entry in radix tree, wait for it to become unlocked if it is | |
164 | * exceptional entry and return it. The caller must call | |
165 | * put_unlocked_mapping_entry() when he decided not to lock the entry or | |
166 | * put_locked_mapping_entry() when he locked the entry and now wants to | |
167 | * unlock it. | |
168 | * | |
169 | * The function must be called with mapping->tree_lock held. | |
170 | */ | |
171 | static void *get_unlocked_mapping_entry(struct address_space *mapping, | |
172 | pgoff_t index, void ***slotp) | |
173 | { | |
e3ad61c6 | 174 | void *entry, **slot; |
ac401cc7 | 175 | struct wait_exceptional_entry_queue ewait; |
63e95b5c | 176 | wait_queue_head_t *wq; |
ac401cc7 JK |
177 | |
178 | init_wait(&ewait.wait); | |
179 | ewait.wait.func = wake_exceptional_entry_func; | |
ac401cc7 JK |
180 | |
181 | for (;;) { | |
e3ad61c6 | 182 | entry = __radix_tree_lookup(&mapping->page_tree, index, NULL, |
ac401cc7 | 183 | &slot); |
e3ad61c6 | 184 | if (!entry || !radix_tree_exceptional_entry(entry) || |
ac401cc7 JK |
185 | !slot_locked(mapping, slot)) { |
186 | if (slotp) | |
187 | *slotp = slot; | |
e3ad61c6 | 188 | return entry; |
ac401cc7 | 189 | } |
63e95b5c RZ |
190 | |
191 | wq = dax_entry_waitqueue(mapping, index, entry, &ewait.key); | |
ac401cc7 JK |
192 | prepare_to_wait_exclusive(wq, &ewait.wait, |
193 | TASK_UNINTERRUPTIBLE); | |
194 | spin_unlock_irq(&mapping->tree_lock); | |
195 | schedule(); | |
196 | finish_wait(wq, &ewait.wait); | |
197 | spin_lock_irq(&mapping->tree_lock); | |
198 | } | |
199 | } | |
200 | ||
b1aa812b JK |
201 | static void dax_unlock_mapping_entry(struct address_space *mapping, |
202 | pgoff_t index) | |
203 | { | |
204 | void *entry, **slot; | |
205 | ||
206 | spin_lock_irq(&mapping->tree_lock); | |
207 | entry = __radix_tree_lookup(&mapping->page_tree, index, NULL, &slot); | |
208 | if (WARN_ON_ONCE(!entry || !radix_tree_exceptional_entry(entry) || | |
209 | !slot_locked(mapping, slot))) { | |
210 | spin_unlock_irq(&mapping->tree_lock); | |
211 | return; | |
212 | } | |
213 | unlock_slot(mapping, slot); | |
214 | spin_unlock_irq(&mapping->tree_lock); | |
215 | dax_wake_mapping_entry_waiter(mapping, index, entry, false); | |
216 | } | |
217 | ||
422476c4 RZ |
218 | static void put_locked_mapping_entry(struct address_space *mapping, |
219 | pgoff_t index, void *entry) | |
220 | { | |
221 | if (!radix_tree_exceptional_entry(entry)) { | |
222 | unlock_page(entry); | |
223 | put_page(entry); | |
224 | } else { | |
225 | dax_unlock_mapping_entry(mapping, index); | |
226 | } | |
227 | } | |
228 | ||
229 | /* | |
230 | * Called when we are done with radix tree entry we looked up via | |
231 | * get_unlocked_mapping_entry() and which we didn't lock in the end. | |
232 | */ | |
233 | static void put_unlocked_mapping_entry(struct address_space *mapping, | |
234 | pgoff_t index, void *entry) | |
235 | { | |
236 | if (!radix_tree_exceptional_entry(entry)) | |
237 | return; | |
238 | ||
239 | /* We have to wake up next waiter for the radix tree entry lock */ | |
240 | dax_wake_mapping_entry_waiter(mapping, index, entry, false); | |
241 | } | |
242 | ||
ac401cc7 JK |
243 | /* |
244 | * Find radix tree entry at given index. If it points to a page, return with | |
245 | * the page locked. If it points to the exceptional entry, return with the | |
246 | * radix tree entry locked. If the radix tree doesn't contain given index, | |
247 | * create empty exceptional entry for the index and return with it locked. | |
248 | * | |
642261ac RZ |
249 | * When requesting an entry with size RADIX_DAX_PMD, grab_mapping_entry() will |
250 | * either return that locked entry or will return an error. This error will | |
251 | * happen if there are any 4k entries (either zero pages or DAX entries) | |
252 | * within the 2MiB range that we are requesting. | |
253 | * | |
254 | * We always favor 4k entries over 2MiB entries. There isn't a flow where we | |
255 | * evict 4k entries in order to 'upgrade' them to a 2MiB entry. A 2MiB | |
256 | * insertion will fail if it finds any 4k entries already in the tree, and a | |
257 | * 4k insertion will cause an existing 2MiB entry to be unmapped and | |
258 | * downgraded to 4k entries. This happens for both 2MiB huge zero pages as | |
259 | * well as 2MiB empty entries. | |
260 | * | |
261 | * The exception to this downgrade path is for 2MiB DAX PMD entries that have | |
262 | * real storage backing them. We will leave these real 2MiB DAX entries in | |
263 | * the tree, and PTE writes will simply dirty the entire 2MiB DAX entry. | |
264 | * | |
ac401cc7 JK |
265 | * Note: Unlike filemap_fault() we don't honor FAULT_FLAG_RETRY flags. For |
266 | * persistent memory the benefit is doubtful. We can add that later if we can | |
267 | * show it helps. | |
268 | */ | |
642261ac RZ |
269 | static void *grab_mapping_entry(struct address_space *mapping, pgoff_t index, |
270 | unsigned long size_flag) | |
ac401cc7 | 271 | { |
642261ac | 272 | bool pmd_downgrade = false; /* splitting 2MiB entry into 4k entries? */ |
e3ad61c6 | 273 | void *entry, **slot; |
ac401cc7 JK |
274 | |
275 | restart: | |
276 | spin_lock_irq(&mapping->tree_lock); | |
e3ad61c6 | 277 | entry = get_unlocked_mapping_entry(mapping, index, &slot); |
642261ac RZ |
278 | |
279 | if (entry) { | |
280 | if (size_flag & RADIX_DAX_PMD) { | |
281 | if (!radix_tree_exceptional_entry(entry) || | |
282 | dax_is_pte_entry(entry)) { | |
283 | put_unlocked_mapping_entry(mapping, index, | |
284 | entry); | |
285 | entry = ERR_PTR(-EEXIST); | |
286 | goto out_unlock; | |
287 | } | |
288 | } else { /* trying to grab a PTE entry */ | |
289 | if (radix_tree_exceptional_entry(entry) && | |
290 | dax_is_pmd_entry(entry) && | |
291 | (dax_is_zero_entry(entry) || | |
292 | dax_is_empty_entry(entry))) { | |
293 | pmd_downgrade = true; | |
294 | } | |
295 | } | |
296 | } | |
297 | ||
ac401cc7 | 298 | /* No entry for given index? Make sure radix tree is big enough. */ |
642261ac | 299 | if (!entry || pmd_downgrade) { |
ac401cc7 JK |
300 | int err; |
301 | ||
642261ac RZ |
302 | if (pmd_downgrade) { |
303 | /* | |
304 | * Make sure 'entry' remains valid while we drop | |
305 | * mapping->tree_lock. | |
306 | */ | |
307 | entry = lock_slot(mapping, slot); | |
308 | } | |
309 | ||
ac401cc7 | 310 | spin_unlock_irq(&mapping->tree_lock); |
642261ac RZ |
311 | /* |
312 | * Besides huge zero pages the only other thing that gets | |
313 | * downgraded are empty entries which don't need to be | |
314 | * unmapped. | |
315 | */ | |
316 | if (pmd_downgrade && dax_is_zero_entry(entry)) | |
317 | unmap_mapping_range(mapping, | |
318 | (index << PAGE_SHIFT) & PMD_MASK, PMD_SIZE, 0); | |
319 | ||
ac401cc7 JK |
320 | err = radix_tree_preload( |
321 | mapping_gfp_mask(mapping) & ~__GFP_HIGHMEM); | |
0cb80b48 JK |
322 | if (err) { |
323 | if (pmd_downgrade) | |
324 | put_locked_mapping_entry(mapping, index, entry); | |
ac401cc7 | 325 | return ERR_PTR(err); |
0cb80b48 | 326 | } |
ac401cc7 | 327 | spin_lock_irq(&mapping->tree_lock); |
642261ac | 328 | |
e11f8b7b RZ |
329 | if (!entry) { |
330 | /* | |
331 | * We needed to drop the page_tree lock while calling | |
332 | * radix_tree_preload() and we didn't have an entry to | |
333 | * lock. See if another thread inserted an entry at | |
334 | * our index during this time. | |
335 | */ | |
336 | entry = __radix_tree_lookup(&mapping->page_tree, index, | |
337 | NULL, &slot); | |
338 | if (entry) { | |
339 | radix_tree_preload_end(); | |
340 | spin_unlock_irq(&mapping->tree_lock); | |
341 | goto restart; | |
342 | } | |
343 | } | |
344 | ||
642261ac RZ |
345 | if (pmd_downgrade) { |
346 | radix_tree_delete(&mapping->page_tree, index); | |
347 | mapping->nrexceptional--; | |
348 | dax_wake_mapping_entry_waiter(mapping, index, entry, | |
349 | true); | |
350 | } | |
351 | ||
352 | entry = dax_radix_locked_entry(0, size_flag | RADIX_DAX_EMPTY); | |
353 | ||
354 | err = __radix_tree_insert(&mapping->page_tree, index, | |
355 | dax_radix_order(entry), entry); | |
ac401cc7 JK |
356 | radix_tree_preload_end(); |
357 | if (err) { | |
358 | spin_unlock_irq(&mapping->tree_lock); | |
642261ac | 359 | /* |
e11f8b7b RZ |
360 | * Our insertion of a DAX entry failed, most likely |
361 | * because we were inserting a PMD entry and it | |
362 | * collided with a PTE sized entry at a different | |
363 | * index in the PMD range. We haven't inserted | |
364 | * anything into the radix tree and have no waiters to | |
365 | * wake. | |
642261ac | 366 | */ |
ac401cc7 JK |
367 | return ERR_PTR(err); |
368 | } | |
369 | /* Good, we have inserted empty locked entry into the tree. */ | |
370 | mapping->nrexceptional++; | |
371 | spin_unlock_irq(&mapping->tree_lock); | |
e3ad61c6 | 372 | return entry; |
ac401cc7 JK |
373 | } |
374 | /* Normal page in radix tree? */ | |
e3ad61c6 RZ |
375 | if (!radix_tree_exceptional_entry(entry)) { |
376 | struct page *page = entry; | |
ac401cc7 JK |
377 | |
378 | get_page(page); | |
379 | spin_unlock_irq(&mapping->tree_lock); | |
380 | lock_page(page); | |
381 | /* Page got truncated? Retry... */ | |
382 | if (unlikely(page->mapping != mapping)) { | |
383 | unlock_page(page); | |
384 | put_page(page); | |
385 | goto restart; | |
386 | } | |
387 | return page; | |
388 | } | |
e3ad61c6 | 389 | entry = lock_slot(mapping, slot); |
642261ac | 390 | out_unlock: |
ac401cc7 | 391 | spin_unlock_irq(&mapping->tree_lock); |
e3ad61c6 | 392 | return entry; |
ac401cc7 JK |
393 | } |
394 | ||
63e95b5c RZ |
395 | /* |
396 | * We do not necessarily hold the mapping->tree_lock when we call this | |
397 | * function so it is possible that 'entry' is no longer a valid item in the | |
642261ac RZ |
398 | * radix tree. This is okay because all we really need to do is to find the |
399 | * correct waitqueue where tasks might be waiting for that old 'entry' and | |
400 | * wake them. | |
63e95b5c | 401 | */ |
ac401cc7 | 402 | void dax_wake_mapping_entry_waiter(struct address_space *mapping, |
63e95b5c | 403 | pgoff_t index, void *entry, bool wake_all) |
ac401cc7 | 404 | { |
63e95b5c RZ |
405 | struct exceptional_entry_key key; |
406 | wait_queue_head_t *wq; | |
407 | ||
408 | wq = dax_entry_waitqueue(mapping, index, entry, &key); | |
ac401cc7 JK |
409 | |
410 | /* | |
411 | * Checking for locked entry and prepare_to_wait_exclusive() happens | |
412 | * under mapping->tree_lock, ditto for entry handling in our callers. | |
413 | * So at this point all tasks that could have seen our entry locked | |
414 | * must be in the waitqueue and the following check will see them. | |
415 | */ | |
63e95b5c | 416 | if (waitqueue_active(wq)) |
ac401cc7 | 417 | __wake_up(wq, TASK_NORMAL, wake_all ? 0 : 1, &key); |
ac401cc7 JK |
418 | } |
419 | ||
c6dcf52c JK |
420 | static int __dax_invalidate_mapping_entry(struct address_space *mapping, |
421 | pgoff_t index, bool trunc) | |
422 | { | |
423 | int ret = 0; | |
424 | void *entry; | |
425 | struct radix_tree_root *page_tree = &mapping->page_tree; | |
426 | ||
427 | spin_lock_irq(&mapping->tree_lock); | |
428 | entry = get_unlocked_mapping_entry(mapping, index, NULL); | |
429 | if (!entry || !radix_tree_exceptional_entry(entry)) | |
430 | goto out; | |
431 | if (!trunc && | |
432 | (radix_tree_tag_get(page_tree, index, PAGECACHE_TAG_DIRTY) || | |
433 | radix_tree_tag_get(page_tree, index, PAGECACHE_TAG_TOWRITE))) | |
434 | goto out; | |
435 | radix_tree_delete(page_tree, index); | |
436 | mapping->nrexceptional--; | |
437 | ret = 1; | |
438 | out: | |
439 | put_unlocked_mapping_entry(mapping, index, entry); | |
440 | spin_unlock_irq(&mapping->tree_lock); | |
441 | return ret; | |
442 | } | |
ac401cc7 JK |
443 | /* |
444 | * Delete exceptional DAX entry at @index from @mapping. Wait for radix tree | |
445 | * entry to get unlocked before deleting it. | |
446 | */ | |
447 | int dax_delete_mapping_entry(struct address_space *mapping, pgoff_t index) | |
448 | { | |
c6dcf52c | 449 | int ret = __dax_invalidate_mapping_entry(mapping, index, true); |
ac401cc7 | 450 | |
ac401cc7 JK |
451 | /* |
452 | * This gets called from truncate / punch_hole path. As such, the caller | |
453 | * must hold locks protecting against concurrent modifications of the | |
454 | * radix tree (usually fs-private i_mmap_sem for writing). Since the | |
455 | * caller has seen exceptional entry for this index, we better find it | |
456 | * at that index as well... | |
457 | */ | |
c6dcf52c JK |
458 | WARN_ON_ONCE(!ret); |
459 | return ret; | |
460 | } | |
461 | ||
c6dcf52c JK |
462 | /* |
463 | * Invalidate exceptional DAX entry if it is clean. | |
464 | */ | |
465 | int dax_invalidate_mapping_entry_sync(struct address_space *mapping, | |
466 | pgoff_t index) | |
467 | { | |
468 | return __dax_invalidate_mapping_entry(mapping, index, false); | |
ac401cc7 JK |
469 | } |
470 | ||
f7ca90b1 MW |
471 | /* |
472 | * The user has performed a load from a hole in the file. Allocating | |
473 | * a new page in the file would cause excessive storage usage for | |
474 | * workloads with sparse files. We allocate a page cache page instead. | |
475 | * We'll kick it out of the page cache if it's ever written to, | |
476 | * otherwise it will simply fall out of the page cache under memory | |
477 | * pressure without ever having been dirtied. | |
478 | */ | |
f449b936 | 479 | static int dax_load_hole(struct address_space *mapping, void **entry, |
ac401cc7 | 480 | struct vm_fault *vmf) |
f7ca90b1 | 481 | { |
678c9fd0 | 482 | struct inode *inode = mapping->host; |
ac401cc7 | 483 | struct page *page; |
f449b936 | 484 | int ret; |
f7ca90b1 | 485 | |
ac401cc7 | 486 | /* Hole page already exists? Return it... */ |
f449b936 JK |
487 | if (!radix_tree_exceptional_entry(*entry)) { |
488 | page = *entry; | |
678c9fd0 | 489 | goto finish_fault; |
ac401cc7 | 490 | } |
f7ca90b1 | 491 | |
ac401cc7 JK |
492 | /* This will replace locked radix tree entry with a hole page */ |
493 | page = find_or_create_page(mapping, vmf->pgoff, | |
494 | vmf->gfp_mask | __GFP_ZERO); | |
678c9fd0 RZ |
495 | if (!page) { |
496 | ret = VM_FAULT_OOM; | |
497 | goto out; | |
498 | } | |
499 | ||
500 | finish_fault: | |
f7ca90b1 | 501 | vmf->page = page; |
f449b936 JK |
502 | ret = finish_fault(vmf); |
503 | vmf->page = NULL; | |
504 | *entry = page; | |
505 | if (!ret) { | |
506 | /* Grab reference for PTE that is now referencing the page */ | |
507 | get_page(page); | |
678c9fd0 | 508 | ret = VM_FAULT_NOPAGE; |
f449b936 | 509 | } |
678c9fd0 RZ |
510 | out: |
511 | trace_dax_load_hole(inode, vmf, ret); | |
f449b936 | 512 | return ret; |
f7ca90b1 MW |
513 | } |
514 | ||
cccbce67 DW |
515 | static int copy_user_dax(struct block_device *bdev, struct dax_device *dax_dev, |
516 | sector_t sector, size_t size, struct page *to, | |
517 | unsigned long vaddr) | |
f7ca90b1 | 518 | { |
cccbce67 DW |
519 | void *vto, *kaddr; |
520 | pgoff_t pgoff; | |
521 | pfn_t pfn; | |
522 | long rc; | |
523 | int id; | |
524 | ||
525 | rc = bdev_dax_pgoff(bdev, sector, size, &pgoff); | |
526 | if (rc) | |
527 | return rc; | |
528 | ||
529 | id = dax_read_lock(); | |
530 | rc = dax_direct_access(dax_dev, pgoff, PHYS_PFN(size), &kaddr, &pfn); | |
531 | if (rc < 0) { | |
532 | dax_read_unlock(id); | |
533 | return rc; | |
534 | } | |
f7ca90b1 | 535 | vto = kmap_atomic(to); |
cccbce67 | 536 | copy_user_page(vto, (void __force *)kaddr, vaddr, to); |
f7ca90b1 | 537 | kunmap_atomic(vto); |
cccbce67 | 538 | dax_read_unlock(id); |
f7ca90b1 MW |
539 | return 0; |
540 | } | |
541 | ||
642261ac RZ |
542 | /* |
543 | * By this point grab_mapping_entry() has ensured that we have a locked entry | |
544 | * of the appropriate size so we don't have to worry about downgrading PMDs to | |
545 | * PTEs. If we happen to be trying to insert a PTE and there is a PMD | |
546 | * already in the tree, we will skip the insertion and just dirty the PMD as | |
547 | * appropriate. | |
548 | */ | |
ac401cc7 JK |
549 | static void *dax_insert_mapping_entry(struct address_space *mapping, |
550 | struct vm_fault *vmf, | |
642261ac RZ |
551 | void *entry, sector_t sector, |
552 | unsigned long flags) | |
9973c98e RZ |
553 | { |
554 | struct radix_tree_root *page_tree = &mapping->page_tree; | |
ac401cc7 JK |
555 | int error = 0; |
556 | bool hole_fill = false; | |
557 | void *new_entry; | |
558 | pgoff_t index = vmf->pgoff; | |
9973c98e | 559 | |
ac401cc7 | 560 | if (vmf->flags & FAULT_FLAG_WRITE) |
d2b2a28e | 561 | __mark_inode_dirty(mapping->host, I_DIRTY_PAGES); |
9973c98e | 562 | |
ac401cc7 JK |
563 | /* Replacing hole page with block mapping? */ |
564 | if (!radix_tree_exceptional_entry(entry)) { | |
565 | hole_fill = true; | |
566 | /* | |
567 | * Unmap the page now before we remove it from page cache below. | |
568 | * The page is locked so it cannot be faulted in again. | |
569 | */ | |
570 | unmap_mapping_range(mapping, vmf->pgoff << PAGE_SHIFT, | |
571 | PAGE_SIZE, 0); | |
572 | error = radix_tree_preload(vmf->gfp_mask & ~__GFP_HIGHMEM); | |
573 | if (error) | |
574 | return ERR_PTR(error); | |
642261ac RZ |
575 | } else if (dax_is_zero_entry(entry) && !(flags & RADIX_DAX_HZP)) { |
576 | /* replacing huge zero page with PMD block mapping */ | |
577 | unmap_mapping_range(mapping, | |
578 | (vmf->pgoff << PAGE_SHIFT) & PMD_MASK, PMD_SIZE, 0); | |
9973c98e RZ |
579 | } |
580 | ||
ac401cc7 | 581 | spin_lock_irq(&mapping->tree_lock); |
642261ac RZ |
582 | new_entry = dax_radix_locked_entry(sector, flags); |
583 | ||
ac401cc7 JK |
584 | if (hole_fill) { |
585 | __delete_from_page_cache(entry, NULL); | |
586 | /* Drop pagecache reference */ | |
587 | put_page(entry); | |
642261ac RZ |
588 | error = __radix_tree_insert(page_tree, index, |
589 | dax_radix_order(new_entry), new_entry); | |
ac401cc7 JK |
590 | if (error) { |
591 | new_entry = ERR_PTR(error); | |
9973c98e RZ |
592 | goto unlock; |
593 | } | |
ac401cc7 | 594 | mapping->nrexceptional++; |
642261ac RZ |
595 | } else if (dax_is_zero_entry(entry) || dax_is_empty_entry(entry)) { |
596 | /* | |
597 | * Only swap our new entry into the radix tree if the current | |
598 | * entry is a zero page or an empty entry. If a normal PTE or | |
599 | * PMD entry is already in the tree, we leave it alone. This | |
600 | * means that if we are trying to insert a PTE and the | |
601 | * existing entry is a PMD, we will just leave the PMD in the | |
602 | * tree and dirty it if necessary. | |
603 | */ | |
f7942430 | 604 | struct radix_tree_node *node; |
ac401cc7 JK |
605 | void **slot; |
606 | void *ret; | |
9973c98e | 607 | |
f7942430 | 608 | ret = __radix_tree_lookup(page_tree, index, &node, &slot); |
ac401cc7 | 609 | WARN_ON_ONCE(ret != entry); |
4d693d08 JW |
610 | __radix_tree_replace(page_tree, node, slot, |
611 | new_entry, NULL, NULL); | |
9973c98e | 612 | } |
ac401cc7 | 613 | if (vmf->flags & FAULT_FLAG_WRITE) |
9973c98e RZ |
614 | radix_tree_tag_set(page_tree, index, PAGECACHE_TAG_DIRTY); |
615 | unlock: | |
616 | spin_unlock_irq(&mapping->tree_lock); | |
ac401cc7 JK |
617 | if (hole_fill) { |
618 | radix_tree_preload_end(); | |
619 | /* | |
620 | * We don't need hole page anymore, it has been replaced with | |
621 | * locked radix tree entry now. | |
622 | */ | |
623 | if (mapping->a_ops->freepage) | |
624 | mapping->a_ops->freepage(entry); | |
625 | unlock_page(entry); | |
626 | put_page(entry); | |
627 | } | |
628 | return new_entry; | |
9973c98e RZ |
629 | } |
630 | ||
4b4bb46d JK |
631 | static inline unsigned long |
632 | pgoff_address(pgoff_t pgoff, struct vm_area_struct *vma) | |
633 | { | |
634 | unsigned long address; | |
635 | ||
636 | address = vma->vm_start + ((pgoff - vma->vm_pgoff) << PAGE_SHIFT); | |
637 | VM_BUG_ON_VMA(address < vma->vm_start || address >= vma->vm_end, vma); | |
638 | return address; | |
639 | } | |
640 | ||
641 | /* Walk all mappings of a given index of a file and writeprotect them */ | |
642 | static void dax_mapping_entry_mkclean(struct address_space *mapping, | |
643 | pgoff_t index, unsigned long pfn) | |
644 | { | |
645 | struct vm_area_struct *vma; | |
f729c8c9 RZ |
646 | pte_t pte, *ptep = NULL; |
647 | pmd_t *pmdp = NULL; | |
4b4bb46d | 648 | spinlock_t *ptl; |
4b4bb46d JK |
649 | |
650 | i_mmap_lock_read(mapping); | |
651 | vma_interval_tree_foreach(vma, &mapping->i_mmap, index, index) { | |
a4d1a885 | 652 | unsigned long address, start, end; |
4b4bb46d JK |
653 | |
654 | cond_resched(); | |
655 | ||
656 | if (!(vma->vm_flags & VM_SHARED)) | |
657 | continue; | |
658 | ||
659 | address = pgoff_address(index, vma); | |
a4d1a885 JG |
660 | |
661 | /* | |
662 | * Note because we provide start/end to follow_pte_pmd it will | |
663 | * call mmu_notifier_invalidate_range_start() on our behalf | |
664 | * before taking any lock. | |
665 | */ | |
666 | if (follow_pte_pmd(vma->vm_mm, address, &start, &end, &ptep, &pmdp, &ptl)) | |
4b4bb46d | 667 | continue; |
4b4bb46d | 668 | |
f729c8c9 RZ |
669 | if (pmdp) { |
670 | #ifdef CONFIG_FS_DAX_PMD | |
671 | pmd_t pmd; | |
672 | ||
673 | if (pfn != pmd_pfn(*pmdp)) | |
674 | goto unlock_pmd; | |
675 | if (!pmd_dirty(*pmdp) && !pmd_write(*pmdp)) | |
676 | goto unlock_pmd; | |
677 | ||
678 | flush_cache_page(vma, address, pfn); | |
679 | pmd = pmdp_huge_clear_flush(vma, address, pmdp); | |
680 | pmd = pmd_wrprotect(pmd); | |
681 | pmd = pmd_mkclean(pmd); | |
682 | set_pmd_at(vma->vm_mm, address, pmdp, pmd); | |
a4d1a885 | 683 | mmu_notifier_invalidate_range(vma->vm_mm, start, end); |
f729c8c9 RZ |
684 | unlock_pmd: |
685 | spin_unlock(ptl); | |
686 | #endif | |
687 | } else { | |
688 | if (pfn != pte_pfn(*ptep)) | |
689 | goto unlock_pte; | |
690 | if (!pte_dirty(*ptep) && !pte_write(*ptep)) | |
691 | goto unlock_pte; | |
692 | ||
693 | flush_cache_page(vma, address, pfn); | |
694 | pte = ptep_clear_flush(vma, address, ptep); | |
695 | pte = pte_wrprotect(pte); | |
696 | pte = pte_mkclean(pte); | |
697 | set_pte_at(vma->vm_mm, address, ptep, pte); | |
a4d1a885 | 698 | mmu_notifier_invalidate_range(vma->vm_mm, start, end); |
f729c8c9 RZ |
699 | unlock_pte: |
700 | pte_unmap_unlock(ptep, ptl); | |
701 | } | |
4b4bb46d | 702 | |
a4d1a885 | 703 | mmu_notifier_invalidate_range_end(vma->vm_mm, start, end); |
4b4bb46d JK |
704 | } |
705 | i_mmap_unlock_read(mapping); | |
706 | } | |
707 | ||
9973c98e | 708 | static int dax_writeback_one(struct block_device *bdev, |
cccbce67 DW |
709 | struct dax_device *dax_dev, struct address_space *mapping, |
710 | pgoff_t index, void *entry) | |
9973c98e RZ |
711 | { |
712 | struct radix_tree_root *page_tree = &mapping->page_tree; | |
cccbce67 DW |
713 | void *entry2, **slot, *kaddr; |
714 | long ret = 0, id; | |
715 | sector_t sector; | |
716 | pgoff_t pgoff; | |
717 | size_t size; | |
718 | pfn_t pfn; | |
9973c98e | 719 | |
9973c98e | 720 | /* |
a6abc2c0 JK |
721 | * A page got tagged dirty in DAX mapping? Something is seriously |
722 | * wrong. | |
9973c98e | 723 | */ |
a6abc2c0 JK |
724 | if (WARN_ON(!radix_tree_exceptional_entry(entry))) |
725 | return -EIO; | |
9973c98e | 726 | |
a6abc2c0 JK |
727 | spin_lock_irq(&mapping->tree_lock); |
728 | entry2 = get_unlocked_mapping_entry(mapping, index, &slot); | |
729 | /* Entry got punched out / reallocated? */ | |
730 | if (!entry2 || !radix_tree_exceptional_entry(entry2)) | |
731 | goto put_unlocked; | |
732 | /* | |
733 | * Entry got reallocated elsewhere? No need to writeback. We have to | |
734 | * compare sectors as we must not bail out due to difference in lockbit | |
735 | * or entry type. | |
736 | */ | |
737 | if (dax_radix_sector(entry2) != dax_radix_sector(entry)) | |
738 | goto put_unlocked; | |
642261ac RZ |
739 | if (WARN_ON_ONCE(dax_is_empty_entry(entry) || |
740 | dax_is_zero_entry(entry))) { | |
9973c98e | 741 | ret = -EIO; |
a6abc2c0 | 742 | goto put_unlocked; |
9973c98e RZ |
743 | } |
744 | ||
a6abc2c0 JK |
745 | /* Another fsync thread may have already written back this entry */ |
746 | if (!radix_tree_tag_get(page_tree, index, PAGECACHE_TAG_TOWRITE)) | |
747 | goto put_unlocked; | |
748 | /* Lock the entry to serialize with page faults */ | |
749 | entry = lock_slot(mapping, slot); | |
750 | /* | |
751 | * We can clear the tag now but we have to be careful so that concurrent | |
752 | * dax_writeback_one() calls for the same index cannot finish before we | |
753 | * actually flush the caches. This is achieved as the calls will look | |
754 | * at the entry only under tree_lock and once they do that they will | |
755 | * see the entry locked and wait for it to unlock. | |
756 | */ | |
757 | radix_tree_tag_clear(page_tree, index, PAGECACHE_TAG_TOWRITE); | |
758 | spin_unlock_irq(&mapping->tree_lock); | |
759 | ||
642261ac RZ |
760 | /* |
761 | * Even if dax_writeback_mapping_range() was given a wbc->range_start | |
762 | * in the middle of a PMD, the 'index' we are given will be aligned to | |
763 | * the start index of the PMD, as will the sector we pull from | |
764 | * 'entry'. This allows us to flush for PMD_SIZE and not have to | |
765 | * worry about partial PMD writebacks. | |
766 | */ | |
cccbce67 DW |
767 | sector = dax_radix_sector(entry); |
768 | size = PAGE_SIZE << dax_radix_order(entry); | |
769 | ||
770 | id = dax_read_lock(); | |
771 | ret = bdev_dax_pgoff(bdev, sector, size, &pgoff); | |
772 | if (ret) | |
773 | goto dax_unlock; | |
9973c98e RZ |
774 | |
775 | /* | |
cccbce67 DW |
776 | * dax_direct_access() may sleep, so cannot hold tree_lock over |
777 | * its invocation. | |
9973c98e | 778 | */ |
cccbce67 DW |
779 | ret = dax_direct_access(dax_dev, pgoff, size / PAGE_SIZE, &kaddr, &pfn); |
780 | if (ret < 0) | |
781 | goto dax_unlock; | |
9973c98e | 782 | |
cccbce67 | 783 | if (WARN_ON_ONCE(ret < size / PAGE_SIZE)) { |
9973c98e | 784 | ret = -EIO; |
cccbce67 | 785 | goto dax_unlock; |
9973c98e RZ |
786 | } |
787 | ||
cccbce67 | 788 | dax_mapping_entry_mkclean(mapping, index, pfn_t_to_pfn(pfn)); |
6318770a | 789 | dax_flush(dax_dev, pgoff, kaddr, size); |
4b4bb46d JK |
790 | /* |
791 | * After we have flushed the cache, we can clear the dirty tag. There | |
792 | * cannot be new dirty data in the pfn after the flush has completed as | |
793 | * the pfn mappings are writeprotected and fault waits for mapping | |
794 | * entry lock. | |
795 | */ | |
796 | spin_lock_irq(&mapping->tree_lock); | |
797 | radix_tree_tag_clear(page_tree, index, PAGECACHE_TAG_DIRTY); | |
798 | spin_unlock_irq(&mapping->tree_lock); | |
f9bc3a07 | 799 | trace_dax_writeback_one(mapping->host, index, size >> PAGE_SHIFT); |
cccbce67 DW |
800 | dax_unlock: |
801 | dax_read_unlock(id); | |
a6abc2c0 | 802 | put_locked_mapping_entry(mapping, index, entry); |
9973c98e RZ |
803 | return ret; |
804 | ||
a6abc2c0 JK |
805 | put_unlocked: |
806 | put_unlocked_mapping_entry(mapping, index, entry2); | |
9973c98e RZ |
807 | spin_unlock_irq(&mapping->tree_lock); |
808 | return ret; | |
809 | } | |
810 | ||
811 | /* | |
812 | * Flush the mapping to the persistent domain within the byte range of [start, | |
813 | * end]. This is required by data integrity operations to ensure file data is | |
814 | * on persistent storage prior to completion of the operation. | |
815 | */ | |
7f6d5b52 RZ |
816 | int dax_writeback_mapping_range(struct address_space *mapping, |
817 | struct block_device *bdev, struct writeback_control *wbc) | |
9973c98e RZ |
818 | { |
819 | struct inode *inode = mapping->host; | |
642261ac | 820 | pgoff_t start_index, end_index; |
9973c98e | 821 | pgoff_t indices[PAGEVEC_SIZE]; |
cccbce67 | 822 | struct dax_device *dax_dev; |
9973c98e RZ |
823 | struct pagevec pvec; |
824 | bool done = false; | |
825 | int i, ret = 0; | |
9973c98e RZ |
826 | |
827 | if (WARN_ON_ONCE(inode->i_blkbits != PAGE_SHIFT)) | |
828 | return -EIO; | |
829 | ||
7f6d5b52 RZ |
830 | if (!mapping->nrexceptional || wbc->sync_mode != WB_SYNC_ALL) |
831 | return 0; | |
832 | ||
cccbce67 DW |
833 | dax_dev = dax_get_by_host(bdev->bd_disk->disk_name); |
834 | if (!dax_dev) | |
835 | return -EIO; | |
836 | ||
09cbfeaf KS |
837 | start_index = wbc->range_start >> PAGE_SHIFT; |
838 | end_index = wbc->range_end >> PAGE_SHIFT; | |
9973c98e | 839 | |
d14a3f48 RZ |
840 | trace_dax_writeback_range(inode, start_index, end_index); |
841 | ||
9973c98e RZ |
842 | tag_pages_for_writeback(mapping, start_index, end_index); |
843 | ||
844 | pagevec_init(&pvec, 0); | |
845 | while (!done) { | |
846 | pvec.nr = find_get_entries_tag(mapping, start_index, | |
847 | PAGECACHE_TAG_TOWRITE, PAGEVEC_SIZE, | |
848 | pvec.pages, indices); | |
849 | ||
850 | if (pvec.nr == 0) | |
851 | break; | |
852 | ||
853 | for (i = 0; i < pvec.nr; i++) { | |
854 | if (indices[i] > end_index) { | |
855 | done = true; | |
856 | break; | |
857 | } | |
858 | ||
cccbce67 DW |
859 | ret = dax_writeback_one(bdev, dax_dev, mapping, |
860 | indices[i], pvec.pages[i]); | |
819ec6b9 JL |
861 | if (ret < 0) { |
862 | mapping_set_error(mapping, ret); | |
d14a3f48 | 863 | goto out; |
819ec6b9 | 864 | } |
9973c98e | 865 | } |
1eb643d0 | 866 | start_index = indices[pvec.nr - 1] + 1; |
9973c98e | 867 | } |
d14a3f48 | 868 | out: |
cccbce67 | 869 | put_dax(dax_dev); |
d14a3f48 RZ |
870 | trace_dax_writeback_range_done(inode, start_index, end_index); |
871 | return (ret < 0 ? ret : 0); | |
9973c98e RZ |
872 | } |
873 | EXPORT_SYMBOL_GPL(dax_writeback_mapping_range); | |
874 | ||
ac401cc7 | 875 | static int dax_insert_mapping(struct address_space *mapping, |
cccbce67 DW |
876 | struct block_device *bdev, struct dax_device *dax_dev, |
877 | sector_t sector, size_t size, void **entryp, | |
878 | struct vm_area_struct *vma, struct vm_fault *vmf) | |
f7ca90b1 | 879 | { |
1a29d85e | 880 | unsigned long vaddr = vmf->address; |
ac401cc7 | 881 | void *entry = *entryp; |
cccbce67 DW |
882 | void *ret, *kaddr; |
883 | pgoff_t pgoff; | |
884 | int id, rc; | |
885 | pfn_t pfn; | |
f7ca90b1 | 886 | |
cccbce67 DW |
887 | rc = bdev_dax_pgoff(bdev, sector, size, &pgoff); |
888 | if (rc) | |
889 | return rc; | |
f7ca90b1 | 890 | |
cccbce67 DW |
891 | id = dax_read_lock(); |
892 | rc = dax_direct_access(dax_dev, pgoff, PHYS_PFN(size), &kaddr, &pfn); | |
893 | if (rc < 0) { | |
894 | dax_read_unlock(id); | |
895 | return rc; | |
896 | } | |
897 | dax_read_unlock(id); | |
898 | ||
899 | ret = dax_insert_mapping_entry(mapping, vmf, entry, sector, 0); | |
4d9a2c87 JK |
900 | if (IS_ERR(ret)) |
901 | return PTR_ERR(ret); | |
ac401cc7 | 902 | *entryp = ret; |
9973c98e | 903 | |
b4440734 | 904 | trace_dax_insert_mapping(mapping->host, vmf, ret); |
cccbce67 | 905 | return vm_insert_mixed(vma, vaddr, pfn); |
f7ca90b1 MW |
906 | } |
907 | ||
0e3b210c BH |
908 | /** |
909 | * dax_pfn_mkwrite - handle first write to DAX page | |
0e3b210c | 910 | * @vmf: The description of the fault |
0e3b210c | 911 | */ |
11bac800 | 912 | int dax_pfn_mkwrite(struct vm_fault *vmf) |
0e3b210c | 913 | { |
11bac800 | 914 | struct file *file = vmf->vma->vm_file; |
ac401cc7 | 915 | struct address_space *mapping = file->f_mapping; |
c3ff68d7 | 916 | struct inode *inode = mapping->host; |
2f89dc12 | 917 | void *entry, **slot; |
ac401cc7 | 918 | pgoff_t index = vmf->pgoff; |
30f471fd | 919 | |
ac401cc7 | 920 | spin_lock_irq(&mapping->tree_lock); |
2f89dc12 JK |
921 | entry = get_unlocked_mapping_entry(mapping, index, &slot); |
922 | if (!entry || !radix_tree_exceptional_entry(entry)) { | |
923 | if (entry) | |
924 | put_unlocked_mapping_entry(mapping, index, entry); | |
925 | spin_unlock_irq(&mapping->tree_lock); | |
c3ff68d7 | 926 | trace_dax_pfn_mkwrite_no_entry(inode, vmf, VM_FAULT_NOPAGE); |
2f89dc12 JK |
927 | return VM_FAULT_NOPAGE; |
928 | } | |
ac401cc7 | 929 | radix_tree_tag_set(&mapping->page_tree, index, PAGECACHE_TAG_DIRTY); |
2f89dc12 | 930 | entry = lock_slot(mapping, slot); |
ac401cc7 | 931 | spin_unlock_irq(&mapping->tree_lock); |
2f89dc12 JK |
932 | /* |
933 | * If we race with somebody updating the PTE and finish_mkwrite_fault() | |
934 | * fails, we don't care. We need to return VM_FAULT_NOPAGE and retry | |
935 | * the fault in either case. | |
936 | */ | |
937 | finish_mkwrite_fault(vmf); | |
938 | put_locked_mapping_entry(mapping, index, entry); | |
c3ff68d7 | 939 | trace_dax_pfn_mkwrite(inode, vmf, VM_FAULT_NOPAGE); |
0e3b210c BH |
940 | return VM_FAULT_NOPAGE; |
941 | } | |
942 | EXPORT_SYMBOL_GPL(dax_pfn_mkwrite); | |
943 | ||
4b0228fa VV |
944 | static bool dax_range_is_aligned(struct block_device *bdev, |
945 | unsigned int offset, unsigned int length) | |
946 | { | |
947 | unsigned short sector_size = bdev_logical_block_size(bdev); | |
948 | ||
949 | if (!IS_ALIGNED(offset, sector_size)) | |
950 | return false; | |
951 | if (!IS_ALIGNED(length, sector_size)) | |
952 | return false; | |
953 | ||
954 | return true; | |
955 | } | |
956 | ||
cccbce67 DW |
957 | int __dax_zero_page_range(struct block_device *bdev, |
958 | struct dax_device *dax_dev, sector_t sector, | |
959 | unsigned int offset, unsigned int size) | |
679c8bd3 | 960 | { |
cccbce67 DW |
961 | if (dax_range_is_aligned(bdev, offset, size)) { |
962 | sector_t start_sector = sector + (offset >> 9); | |
4b0228fa VV |
963 | |
964 | return blkdev_issue_zeroout(bdev, start_sector, | |
53ef7d0e | 965 | size >> 9, GFP_NOFS, 0); |
4b0228fa | 966 | } else { |
cccbce67 DW |
967 | pgoff_t pgoff; |
968 | long rc, id; | |
969 | void *kaddr; | |
970 | pfn_t pfn; | |
971 | ||
e84b83b9 | 972 | rc = bdev_dax_pgoff(bdev, sector, PAGE_SIZE, &pgoff); |
cccbce67 DW |
973 | if (rc) |
974 | return rc; | |
975 | ||
976 | id = dax_read_lock(); | |
e84b83b9 | 977 | rc = dax_direct_access(dax_dev, pgoff, 1, &kaddr, |
cccbce67 DW |
978 | &pfn); |
979 | if (rc < 0) { | |
980 | dax_read_unlock(id); | |
981 | return rc; | |
982 | } | |
81f55870 DW |
983 | memset(kaddr + offset, 0, size); |
984 | dax_flush(dax_dev, pgoff, kaddr + offset, size); | |
cccbce67 | 985 | dax_read_unlock(id); |
4b0228fa | 986 | } |
679c8bd3 CH |
987 | return 0; |
988 | } | |
989 | EXPORT_SYMBOL_GPL(__dax_zero_page_range); | |
990 | ||
333ccc97 | 991 | static sector_t dax_iomap_sector(struct iomap *iomap, loff_t pos) |
25726bc1 | 992 | { |
333ccc97 | 993 | return iomap->blkno + (((pos & PAGE_MASK) - iomap->offset) >> 9); |
25726bc1 | 994 | } |
a254e568 | 995 | |
a254e568 | 996 | static loff_t |
11c59c92 | 997 | dax_iomap_actor(struct inode *inode, loff_t pos, loff_t length, void *data, |
a254e568 CH |
998 | struct iomap *iomap) |
999 | { | |
cccbce67 DW |
1000 | struct block_device *bdev = iomap->bdev; |
1001 | struct dax_device *dax_dev = iomap->dax_dev; | |
a254e568 CH |
1002 | struct iov_iter *iter = data; |
1003 | loff_t end = pos + length, done = 0; | |
1004 | ssize_t ret = 0; | |
cccbce67 | 1005 | int id; |
a254e568 CH |
1006 | |
1007 | if (iov_iter_rw(iter) == READ) { | |
1008 | end = min(end, i_size_read(inode)); | |
1009 | if (pos >= end) | |
1010 | return 0; | |
1011 | ||
1012 | if (iomap->type == IOMAP_HOLE || iomap->type == IOMAP_UNWRITTEN) | |
1013 | return iov_iter_zero(min(length, end - pos), iter); | |
1014 | } | |
1015 | ||
1016 | if (WARN_ON_ONCE(iomap->type != IOMAP_MAPPED)) | |
1017 | return -EIO; | |
1018 | ||
e3fce68c JK |
1019 | /* |
1020 | * Write can allocate block for an area which has a hole page mapped | |
1021 | * into page tables. We have to tear down these mappings so that data | |
1022 | * written by write(2) is visible in mmap. | |
1023 | */ | |
cd656375 | 1024 | if (iomap->flags & IOMAP_F_NEW) { |
e3fce68c JK |
1025 | invalidate_inode_pages2_range(inode->i_mapping, |
1026 | pos >> PAGE_SHIFT, | |
1027 | (end - 1) >> PAGE_SHIFT); | |
1028 | } | |
1029 | ||
cccbce67 | 1030 | id = dax_read_lock(); |
a254e568 CH |
1031 | while (pos < end) { |
1032 | unsigned offset = pos & (PAGE_SIZE - 1); | |
cccbce67 DW |
1033 | const size_t size = ALIGN(length + offset, PAGE_SIZE); |
1034 | const sector_t sector = dax_iomap_sector(iomap, pos); | |
a254e568 | 1035 | ssize_t map_len; |
cccbce67 DW |
1036 | pgoff_t pgoff; |
1037 | void *kaddr; | |
1038 | pfn_t pfn; | |
a254e568 | 1039 | |
d1908f52 MH |
1040 | if (fatal_signal_pending(current)) { |
1041 | ret = -EINTR; | |
1042 | break; | |
1043 | } | |
1044 | ||
cccbce67 DW |
1045 | ret = bdev_dax_pgoff(bdev, sector, size, &pgoff); |
1046 | if (ret) | |
1047 | break; | |
1048 | ||
1049 | map_len = dax_direct_access(dax_dev, pgoff, PHYS_PFN(size), | |
1050 | &kaddr, &pfn); | |
a254e568 CH |
1051 | if (map_len < 0) { |
1052 | ret = map_len; | |
1053 | break; | |
1054 | } | |
1055 | ||
cccbce67 DW |
1056 | map_len = PFN_PHYS(map_len); |
1057 | kaddr += offset; | |
a254e568 CH |
1058 | map_len -= offset; |
1059 | if (map_len > end - pos) | |
1060 | map_len = end - pos; | |
1061 | ||
1062 | if (iov_iter_rw(iter) == WRITE) | |
fec53774 DW |
1063 | map_len = dax_copy_from_iter(dax_dev, pgoff, kaddr, |
1064 | map_len, iter); | |
a254e568 | 1065 | else |
cccbce67 | 1066 | map_len = copy_to_iter(kaddr, map_len, iter); |
a254e568 CH |
1067 | if (map_len <= 0) { |
1068 | ret = map_len ? map_len : -EFAULT; | |
1069 | break; | |
1070 | } | |
1071 | ||
1072 | pos += map_len; | |
1073 | length -= map_len; | |
1074 | done += map_len; | |
1075 | } | |
cccbce67 | 1076 | dax_read_unlock(id); |
a254e568 CH |
1077 | |
1078 | return done ? done : ret; | |
1079 | } | |
1080 | ||
1081 | /** | |
11c59c92 | 1082 | * dax_iomap_rw - Perform I/O to a DAX file |
a254e568 CH |
1083 | * @iocb: The control block for this I/O |
1084 | * @iter: The addresses to do I/O from or to | |
1085 | * @ops: iomap ops passed from the file system | |
1086 | * | |
1087 | * This function performs read and write operations to directly mapped | |
1088 | * persistent memory. The callers needs to take care of read/write exclusion | |
1089 | * and evicting any page cache pages in the region under I/O. | |
1090 | */ | |
1091 | ssize_t | |
11c59c92 | 1092 | dax_iomap_rw(struct kiocb *iocb, struct iov_iter *iter, |
8ff6daa1 | 1093 | const struct iomap_ops *ops) |
a254e568 CH |
1094 | { |
1095 | struct address_space *mapping = iocb->ki_filp->f_mapping; | |
1096 | struct inode *inode = mapping->host; | |
1097 | loff_t pos = iocb->ki_pos, ret = 0, done = 0; | |
1098 | unsigned flags = 0; | |
1099 | ||
168316db CH |
1100 | if (iov_iter_rw(iter) == WRITE) { |
1101 | lockdep_assert_held_exclusive(&inode->i_rwsem); | |
a254e568 | 1102 | flags |= IOMAP_WRITE; |
168316db CH |
1103 | } else { |
1104 | lockdep_assert_held(&inode->i_rwsem); | |
1105 | } | |
a254e568 | 1106 | |
a254e568 CH |
1107 | while (iov_iter_count(iter)) { |
1108 | ret = iomap_apply(inode, pos, iov_iter_count(iter), flags, ops, | |
11c59c92 | 1109 | iter, dax_iomap_actor); |
a254e568 CH |
1110 | if (ret <= 0) |
1111 | break; | |
1112 | pos += ret; | |
1113 | done += ret; | |
1114 | } | |
1115 | ||
1116 | iocb->ki_pos += done; | |
1117 | return done ? done : ret; | |
1118 | } | |
11c59c92 | 1119 | EXPORT_SYMBOL_GPL(dax_iomap_rw); |
a7d73fe6 | 1120 | |
9f141d6e JK |
1121 | static int dax_fault_return(int error) |
1122 | { | |
1123 | if (error == 0) | |
1124 | return VM_FAULT_NOPAGE; | |
1125 | if (error == -ENOMEM) | |
1126 | return VM_FAULT_OOM; | |
1127 | return VM_FAULT_SIGBUS; | |
1128 | } | |
1129 | ||
a2d58167 DJ |
1130 | static int dax_iomap_pte_fault(struct vm_fault *vmf, |
1131 | const struct iomap_ops *ops) | |
a7d73fe6 | 1132 | { |
11bac800 | 1133 | struct address_space *mapping = vmf->vma->vm_file->f_mapping; |
a7d73fe6 | 1134 | struct inode *inode = mapping->host; |
1a29d85e | 1135 | unsigned long vaddr = vmf->address; |
a7d73fe6 CH |
1136 | loff_t pos = (loff_t)vmf->pgoff << PAGE_SHIFT; |
1137 | sector_t sector; | |
1138 | struct iomap iomap = { 0 }; | |
9484ab1b | 1139 | unsigned flags = IOMAP_FAULT; |
a7d73fe6 | 1140 | int error, major = 0; |
b1aa812b | 1141 | int vmf_ret = 0; |
a7d73fe6 CH |
1142 | void *entry; |
1143 | ||
a9c42b33 | 1144 | trace_dax_pte_fault(inode, vmf, vmf_ret); |
a7d73fe6 CH |
1145 | /* |
1146 | * Check whether offset isn't beyond end of file now. Caller is supposed | |
1147 | * to hold locks serializing us with truncate / punch hole so this is | |
1148 | * a reliable test. | |
1149 | */ | |
a9c42b33 RZ |
1150 | if (pos >= i_size_read(inode)) { |
1151 | vmf_ret = VM_FAULT_SIGBUS; | |
1152 | goto out; | |
1153 | } | |
a7d73fe6 | 1154 | |
a7d73fe6 CH |
1155 | if ((vmf->flags & FAULT_FLAG_WRITE) && !vmf->cow_page) |
1156 | flags |= IOMAP_WRITE; | |
1157 | ||
13e451fd JK |
1158 | entry = grab_mapping_entry(mapping, vmf->pgoff, 0); |
1159 | if (IS_ERR(entry)) { | |
1160 | vmf_ret = dax_fault_return(PTR_ERR(entry)); | |
1161 | goto out; | |
1162 | } | |
1163 | ||
e2093926 RZ |
1164 | /* |
1165 | * It is possible, particularly with mixed reads & writes to private | |
1166 | * mappings, that we have raced with a PMD fault that overlaps with | |
1167 | * the PTE we need to set up. If so just return and the fault will be | |
1168 | * retried. | |
1169 | */ | |
1170 | if (pmd_trans_huge(*vmf->pmd) || pmd_devmap(*vmf->pmd)) { | |
1171 | vmf_ret = VM_FAULT_NOPAGE; | |
1172 | goto unlock_entry; | |
1173 | } | |
1174 | ||
a7d73fe6 CH |
1175 | /* |
1176 | * Note that we don't bother to use iomap_apply here: DAX required | |
1177 | * the file system block size to be equal the page size, which means | |
1178 | * that we never have to deal with more than a single extent here. | |
1179 | */ | |
1180 | error = ops->iomap_begin(inode, pos, PAGE_SIZE, flags, &iomap); | |
a9c42b33 RZ |
1181 | if (error) { |
1182 | vmf_ret = dax_fault_return(error); | |
13e451fd | 1183 | goto unlock_entry; |
a9c42b33 | 1184 | } |
a7d73fe6 | 1185 | if (WARN_ON_ONCE(iomap.offset + iomap.length < pos + PAGE_SIZE)) { |
13e451fd JK |
1186 | error = -EIO; /* fs corruption? */ |
1187 | goto error_finish_iomap; | |
a7d73fe6 CH |
1188 | } |
1189 | ||
333ccc97 | 1190 | sector = dax_iomap_sector(&iomap, pos); |
a7d73fe6 CH |
1191 | |
1192 | if (vmf->cow_page) { | |
1193 | switch (iomap.type) { | |
1194 | case IOMAP_HOLE: | |
1195 | case IOMAP_UNWRITTEN: | |
1196 | clear_user_highpage(vmf->cow_page, vaddr); | |
1197 | break; | |
1198 | case IOMAP_MAPPED: | |
cccbce67 DW |
1199 | error = copy_user_dax(iomap.bdev, iomap.dax_dev, |
1200 | sector, PAGE_SIZE, vmf->cow_page, vaddr); | |
a7d73fe6 CH |
1201 | break; |
1202 | default: | |
1203 | WARN_ON_ONCE(1); | |
1204 | error = -EIO; | |
1205 | break; | |
1206 | } | |
1207 | ||
1208 | if (error) | |
13e451fd | 1209 | goto error_finish_iomap; |
b1aa812b JK |
1210 | |
1211 | __SetPageUptodate(vmf->cow_page); | |
1212 | vmf_ret = finish_fault(vmf); | |
1213 | if (!vmf_ret) | |
1214 | vmf_ret = VM_FAULT_DONE_COW; | |
13e451fd | 1215 | goto finish_iomap; |
a7d73fe6 CH |
1216 | } |
1217 | ||
1218 | switch (iomap.type) { | |
1219 | case IOMAP_MAPPED: | |
1220 | if (iomap.flags & IOMAP_F_NEW) { | |
1221 | count_vm_event(PGMAJFAULT); | |
2262185c | 1222 | count_memcg_event_mm(vmf->vma->vm_mm, PGMAJFAULT); |
a7d73fe6 CH |
1223 | major = VM_FAULT_MAJOR; |
1224 | } | |
cccbce67 DW |
1225 | error = dax_insert_mapping(mapping, iomap.bdev, iomap.dax_dev, |
1226 | sector, PAGE_SIZE, &entry, vmf->vma, vmf); | |
9f141d6e JK |
1227 | /* -EBUSY is fine, somebody else faulted on the same PTE */ |
1228 | if (error == -EBUSY) | |
1229 | error = 0; | |
a7d73fe6 CH |
1230 | break; |
1231 | case IOMAP_UNWRITTEN: | |
1232 | case IOMAP_HOLE: | |
1550290b | 1233 | if (!(vmf->flags & FAULT_FLAG_WRITE)) { |
f449b936 | 1234 | vmf_ret = dax_load_hole(mapping, &entry, vmf); |
13e451fd | 1235 | goto finish_iomap; |
1550290b | 1236 | } |
a7d73fe6 CH |
1237 | /*FALLTHRU*/ |
1238 | default: | |
1239 | WARN_ON_ONCE(1); | |
1240 | error = -EIO; | |
1241 | break; | |
1242 | } | |
1243 | ||
13e451fd | 1244 | error_finish_iomap: |
9f141d6e | 1245 | vmf_ret = dax_fault_return(error) | major; |
9f141d6e JK |
1246 | finish_iomap: |
1247 | if (ops->iomap_end) { | |
1248 | int copied = PAGE_SIZE; | |
1249 | ||
1250 | if (vmf_ret & VM_FAULT_ERROR) | |
1251 | copied = 0; | |
1252 | /* | |
1253 | * The fault is done by now and there's no way back (other | |
1254 | * thread may be already happily using PTE we have installed). | |
1255 | * Just ignore error from ->iomap_end since we cannot do much | |
1256 | * with it. | |
1257 | */ | |
1258 | ops->iomap_end(inode, pos, PAGE_SIZE, copied, flags, &iomap); | |
1550290b | 1259 | } |
13e451fd JK |
1260 | unlock_entry: |
1261 | put_locked_mapping_entry(mapping, vmf->pgoff, entry); | |
1262 | out: | |
a9c42b33 | 1263 | trace_dax_pte_fault_done(inode, vmf, vmf_ret); |
9f141d6e | 1264 | return vmf_ret; |
a7d73fe6 | 1265 | } |
642261ac RZ |
1266 | |
1267 | #ifdef CONFIG_FS_DAX_PMD | |
1268 | /* | |
1269 | * The 'colour' (ie low bits) within a PMD of a page offset. This comes up | |
1270 | * more often than one might expect in the below functions. | |
1271 | */ | |
1272 | #define PG_PMD_COLOUR ((PMD_SIZE >> PAGE_SHIFT) - 1) | |
1273 | ||
f4200391 DJ |
1274 | static int dax_pmd_insert_mapping(struct vm_fault *vmf, struct iomap *iomap, |
1275 | loff_t pos, void **entryp) | |
642261ac | 1276 | { |
f4200391 | 1277 | struct address_space *mapping = vmf->vma->vm_file->f_mapping; |
cccbce67 DW |
1278 | const sector_t sector = dax_iomap_sector(iomap, pos); |
1279 | struct dax_device *dax_dev = iomap->dax_dev; | |
642261ac | 1280 | struct block_device *bdev = iomap->bdev; |
27a7ffac | 1281 | struct inode *inode = mapping->host; |
cccbce67 DW |
1282 | const size_t size = PMD_SIZE; |
1283 | void *ret = NULL, *kaddr; | |
1284 | long length = 0; | |
1285 | pgoff_t pgoff; | |
1286 | pfn_t pfn; | |
1287 | int id; | |
1288 | ||
1289 | if (bdev_dax_pgoff(bdev, sector, size, &pgoff) != 0) | |
27a7ffac | 1290 | goto fallback; |
642261ac | 1291 | |
cccbce67 DW |
1292 | id = dax_read_lock(); |
1293 | length = dax_direct_access(dax_dev, pgoff, PHYS_PFN(size), &kaddr, &pfn); | |
1294 | if (length < 0) | |
1295 | goto unlock_fallback; | |
1296 | length = PFN_PHYS(length); | |
1297 | ||
1298 | if (length < size) | |
1299 | goto unlock_fallback; | |
1300 | if (pfn_t_to_pfn(pfn) & PG_PMD_COLOUR) | |
1301 | goto unlock_fallback; | |
1302 | if (!pfn_t_devmap(pfn)) | |
1303 | goto unlock_fallback; | |
1304 | dax_read_unlock(id); | |
1305 | ||
1306 | ret = dax_insert_mapping_entry(mapping, vmf, *entryp, sector, | |
642261ac RZ |
1307 | RADIX_DAX_PMD); |
1308 | if (IS_ERR(ret)) | |
27a7ffac | 1309 | goto fallback; |
642261ac RZ |
1310 | *entryp = ret; |
1311 | ||
cccbce67 | 1312 | trace_dax_pmd_insert_mapping(inode, vmf, length, pfn, ret); |
f4200391 | 1313 | return vmf_insert_pfn_pmd(vmf->vma, vmf->address, vmf->pmd, |
cccbce67 | 1314 | pfn, vmf->flags & FAULT_FLAG_WRITE); |
642261ac | 1315 | |
cccbce67 DW |
1316 | unlock_fallback: |
1317 | dax_read_unlock(id); | |
27a7ffac | 1318 | fallback: |
cccbce67 | 1319 | trace_dax_pmd_insert_mapping_fallback(inode, vmf, length, pfn, ret); |
642261ac RZ |
1320 | return VM_FAULT_FALLBACK; |
1321 | } | |
1322 | ||
f4200391 DJ |
1323 | static int dax_pmd_load_hole(struct vm_fault *vmf, struct iomap *iomap, |
1324 | void **entryp) | |
642261ac | 1325 | { |
f4200391 DJ |
1326 | struct address_space *mapping = vmf->vma->vm_file->f_mapping; |
1327 | unsigned long pmd_addr = vmf->address & PMD_MASK; | |
653b2ea3 | 1328 | struct inode *inode = mapping->host; |
642261ac | 1329 | struct page *zero_page; |
653b2ea3 | 1330 | void *ret = NULL; |
642261ac RZ |
1331 | spinlock_t *ptl; |
1332 | pmd_t pmd_entry; | |
642261ac | 1333 | |
f4200391 | 1334 | zero_page = mm_get_huge_zero_page(vmf->vma->vm_mm); |
642261ac RZ |
1335 | |
1336 | if (unlikely(!zero_page)) | |
653b2ea3 | 1337 | goto fallback; |
642261ac RZ |
1338 | |
1339 | ret = dax_insert_mapping_entry(mapping, vmf, *entryp, 0, | |
1340 | RADIX_DAX_PMD | RADIX_DAX_HZP); | |
1341 | if (IS_ERR(ret)) | |
653b2ea3 | 1342 | goto fallback; |
642261ac RZ |
1343 | *entryp = ret; |
1344 | ||
f4200391 DJ |
1345 | ptl = pmd_lock(vmf->vma->vm_mm, vmf->pmd); |
1346 | if (!pmd_none(*(vmf->pmd))) { | |
642261ac | 1347 | spin_unlock(ptl); |
653b2ea3 | 1348 | goto fallback; |
642261ac RZ |
1349 | } |
1350 | ||
f4200391 | 1351 | pmd_entry = mk_pmd(zero_page, vmf->vma->vm_page_prot); |
642261ac | 1352 | pmd_entry = pmd_mkhuge(pmd_entry); |
f4200391 | 1353 | set_pmd_at(vmf->vma->vm_mm, pmd_addr, vmf->pmd, pmd_entry); |
642261ac | 1354 | spin_unlock(ptl); |
f4200391 | 1355 | trace_dax_pmd_load_hole(inode, vmf, zero_page, ret); |
642261ac | 1356 | return VM_FAULT_NOPAGE; |
653b2ea3 RZ |
1357 | |
1358 | fallback: | |
f4200391 | 1359 | trace_dax_pmd_load_hole_fallback(inode, vmf, zero_page, ret); |
653b2ea3 | 1360 | return VM_FAULT_FALLBACK; |
642261ac RZ |
1361 | } |
1362 | ||
a2d58167 DJ |
1363 | static int dax_iomap_pmd_fault(struct vm_fault *vmf, |
1364 | const struct iomap_ops *ops) | |
642261ac | 1365 | { |
f4200391 | 1366 | struct vm_area_struct *vma = vmf->vma; |
642261ac | 1367 | struct address_space *mapping = vma->vm_file->f_mapping; |
d8a849e1 DJ |
1368 | unsigned long pmd_addr = vmf->address & PMD_MASK; |
1369 | bool write = vmf->flags & FAULT_FLAG_WRITE; | |
9484ab1b | 1370 | unsigned int iomap_flags = (write ? IOMAP_WRITE : 0) | IOMAP_FAULT; |
642261ac RZ |
1371 | struct inode *inode = mapping->host; |
1372 | int result = VM_FAULT_FALLBACK; | |
1373 | struct iomap iomap = { 0 }; | |
1374 | pgoff_t max_pgoff, pgoff; | |
642261ac RZ |
1375 | void *entry; |
1376 | loff_t pos; | |
1377 | int error; | |
1378 | ||
282a8e03 RZ |
1379 | /* |
1380 | * Check whether offset isn't beyond end of file now. Caller is | |
1381 | * supposed to hold locks serializing us with truncate / punch hole so | |
1382 | * this is a reliable test. | |
1383 | */ | |
1384 | pgoff = linear_page_index(vma, pmd_addr); | |
1385 | max_pgoff = (i_size_read(inode) - 1) >> PAGE_SHIFT; | |
1386 | ||
f4200391 | 1387 | trace_dax_pmd_fault(inode, vmf, max_pgoff, 0); |
282a8e03 | 1388 | |
fffa281b RZ |
1389 | /* |
1390 | * Make sure that the faulting address's PMD offset (color) matches | |
1391 | * the PMD offset from the start of the file. This is necessary so | |
1392 | * that a PMD range in the page table overlaps exactly with a PMD | |
1393 | * range in the radix tree. | |
1394 | */ | |
1395 | if ((vmf->pgoff & PG_PMD_COLOUR) != | |
1396 | ((vmf->address >> PAGE_SHIFT) & PG_PMD_COLOUR)) | |
1397 | goto fallback; | |
1398 | ||
642261ac RZ |
1399 | /* Fall back to PTEs if we're going to COW */ |
1400 | if (write && !(vma->vm_flags & VM_SHARED)) | |
1401 | goto fallback; | |
1402 | ||
1403 | /* If the PMD would extend outside the VMA */ | |
1404 | if (pmd_addr < vma->vm_start) | |
1405 | goto fallback; | |
1406 | if ((pmd_addr + PMD_SIZE) > vma->vm_end) | |
1407 | goto fallback; | |
1408 | ||
282a8e03 RZ |
1409 | if (pgoff > max_pgoff) { |
1410 | result = VM_FAULT_SIGBUS; | |
1411 | goto out; | |
1412 | } | |
642261ac RZ |
1413 | |
1414 | /* If the PMD would extend beyond the file size */ | |
1415 | if ((pgoff | PG_PMD_COLOUR) > max_pgoff) | |
1416 | goto fallback; | |
1417 | ||
876f2946 RZ |
1418 | /* |
1419 | * grab_mapping_entry() will make sure we get a 2M empty entry, a DAX | |
1420 | * PMD or a HZP entry. If it can't (because a 4k page is already in | |
1421 | * the tree, for instance), it will return -EEXIST and we just fall | |
1422 | * back to 4k entries. | |
1423 | */ | |
1424 | entry = grab_mapping_entry(mapping, pgoff, RADIX_DAX_PMD); | |
1425 | if (IS_ERR(entry)) | |
1426 | goto fallback; | |
1427 | ||
e2093926 RZ |
1428 | /* |
1429 | * It is possible, particularly with mixed reads & writes to private | |
1430 | * mappings, that we have raced with a PTE fault that overlaps with | |
1431 | * the PMD we need to set up. If so just return and the fault will be | |
1432 | * retried. | |
1433 | */ | |
1434 | if (!pmd_none(*vmf->pmd) && !pmd_trans_huge(*vmf->pmd) && | |
1435 | !pmd_devmap(*vmf->pmd)) { | |
1436 | result = 0; | |
1437 | goto unlock_entry; | |
1438 | } | |
1439 | ||
642261ac RZ |
1440 | /* |
1441 | * Note that we don't use iomap_apply here. We aren't doing I/O, only | |
1442 | * setting up a mapping, so really we're using iomap_begin() as a way | |
1443 | * to look up our filesystem block. | |
1444 | */ | |
1445 | pos = (loff_t)pgoff << PAGE_SHIFT; | |
1446 | error = ops->iomap_begin(inode, pos, PMD_SIZE, iomap_flags, &iomap); | |
1447 | if (error) | |
876f2946 | 1448 | goto unlock_entry; |
9f141d6e | 1449 | |
642261ac RZ |
1450 | if (iomap.offset + iomap.length < pos + PMD_SIZE) |
1451 | goto finish_iomap; | |
1452 | ||
642261ac RZ |
1453 | switch (iomap.type) { |
1454 | case IOMAP_MAPPED: | |
f4200391 | 1455 | result = dax_pmd_insert_mapping(vmf, &iomap, pos, &entry); |
642261ac RZ |
1456 | break; |
1457 | case IOMAP_UNWRITTEN: | |
1458 | case IOMAP_HOLE: | |
1459 | if (WARN_ON_ONCE(write)) | |
876f2946 | 1460 | break; |
f4200391 | 1461 | result = dax_pmd_load_hole(vmf, &iomap, &entry); |
642261ac RZ |
1462 | break; |
1463 | default: | |
1464 | WARN_ON_ONCE(1); | |
1465 | break; | |
1466 | } | |
1467 | ||
1468 | finish_iomap: | |
1469 | if (ops->iomap_end) { | |
9f141d6e JK |
1470 | int copied = PMD_SIZE; |
1471 | ||
1472 | if (result == VM_FAULT_FALLBACK) | |
1473 | copied = 0; | |
1474 | /* | |
1475 | * The fault is done by now and there's no way back (other | |
1476 | * thread may be already happily using PMD we have installed). | |
1477 | * Just ignore error from ->iomap_end since we cannot do much | |
1478 | * with it. | |
1479 | */ | |
1480 | ops->iomap_end(inode, pos, PMD_SIZE, copied, iomap_flags, | |
1481 | &iomap); | |
642261ac | 1482 | } |
876f2946 RZ |
1483 | unlock_entry: |
1484 | put_locked_mapping_entry(mapping, pgoff, entry); | |
642261ac RZ |
1485 | fallback: |
1486 | if (result == VM_FAULT_FALLBACK) { | |
d8a849e1 | 1487 | split_huge_pmd(vma, vmf->pmd, vmf->address); |
642261ac RZ |
1488 | count_vm_event(THP_FAULT_FALLBACK); |
1489 | } | |
282a8e03 | 1490 | out: |
f4200391 | 1491 | trace_dax_pmd_fault_done(inode, vmf, max_pgoff, result); |
642261ac RZ |
1492 | return result; |
1493 | } | |
a2d58167 | 1494 | #else |
01cddfe9 AB |
1495 | static int dax_iomap_pmd_fault(struct vm_fault *vmf, |
1496 | const struct iomap_ops *ops) | |
a2d58167 DJ |
1497 | { |
1498 | return VM_FAULT_FALLBACK; | |
1499 | } | |
642261ac | 1500 | #endif /* CONFIG_FS_DAX_PMD */ |
a2d58167 DJ |
1501 | |
1502 | /** | |
1503 | * dax_iomap_fault - handle a page fault on a DAX file | |
1504 | * @vmf: The description of the fault | |
1505 | * @ops: iomap ops passed from the file system | |
1506 | * | |
1507 | * When a page fault occurs, filesystems may call this helper in | |
1508 | * their fault handler for DAX files. dax_iomap_fault() assumes the caller | |
1509 | * has done all the necessary locking for page fault to proceed | |
1510 | * successfully. | |
1511 | */ | |
c791ace1 DJ |
1512 | int dax_iomap_fault(struct vm_fault *vmf, enum page_entry_size pe_size, |
1513 | const struct iomap_ops *ops) | |
a2d58167 | 1514 | { |
c791ace1 DJ |
1515 | switch (pe_size) { |
1516 | case PE_SIZE_PTE: | |
a2d58167 | 1517 | return dax_iomap_pte_fault(vmf, ops); |
c791ace1 | 1518 | case PE_SIZE_PMD: |
a2d58167 DJ |
1519 | return dax_iomap_pmd_fault(vmf, ops); |
1520 | default: | |
1521 | return VM_FAULT_FALLBACK; | |
1522 | } | |
1523 | } | |
1524 | EXPORT_SYMBOL_GPL(dax_iomap_fault); |