1 // SPDX-License-Identifier: GPL-2.0-only 1 // SPDX-License-Identifier: GPL-2.0-only
2 /* 2 /*
3 * fs/dax.c - Direct Access filesystem code 3 * fs/dax.c - Direct Access filesystem code
4 * Copyright (c) 2013-2014 Intel Corporation 4 * Copyright (c) 2013-2014 Intel Corporation
5 * Author: Matthew Wilcox <matthew.r.wilcox@in 5 * Author: Matthew Wilcox <matthew.r.wilcox@intel.com>
6 * Author: Ross Zwisler <ross.zwisler@linux.in 6 * Author: Ross Zwisler <ross.zwisler@linux.intel.com>
7 */ 7 */
8 8
9 #include <linux/atomic.h> 9 #include <linux/atomic.h>
10 #include <linux/blkdev.h> 10 #include <linux/blkdev.h>
11 #include <linux/buffer_head.h> 11 #include <linux/buffer_head.h>
12 #include <linux/dax.h> 12 #include <linux/dax.h>
13 #include <linux/fs.h> 13 #include <linux/fs.h>
14 #include <linux/highmem.h> 14 #include <linux/highmem.h>
15 #include <linux/memcontrol.h> 15 #include <linux/memcontrol.h>
16 #include <linux/mm.h> 16 #include <linux/mm.h>
17 #include <linux/mutex.h> 17 #include <linux/mutex.h>
18 #include <linux/pagevec.h> 18 #include <linux/pagevec.h>
19 #include <linux/sched.h> 19 #include <linux/sched.h>
20 #include <linux/sched/signal.h> 20 #include <linux/sched/signal.h>
21 #include <linux/uio.h> 21 #include <linux/uio.h>
22 #include <linux/vmstat.h> 22 #include <linux/vmstat.h>
23 #include <linux/pfn_t.h> 23 #include <linux/pfn_t.h>
24 #include <linux/sizes.h> 24 #include <linux/sizes.h>
25 #include <linux/mmu_notifier.h> 25 #include <linux/mmu_notifier.h>
26 #include <linux/iomap.h> 26 #include <linux/iomap.h>
27 #include <linux/rmap.h> 27 #include <linux/rmap.h>
28 #include <asm/pgalloc.h> 28 #include <asm/pgalloc.h>
29 29
30 #define CREATE_TRACE_POINTS 30 #define CREATE_TRACE_POINTS
31 #include <trace/events/fs_dax.h> 31 #include <trace/events/fs_dax.h>
32 32
33 /* We choose 4096 entries - same as per-zone p 33 /* We choose 4096 entries - same as per-zone page wait tables */
34 #define DAX_WAIT_TABLE_BITS 12 34 #define DAX_WAIT_TABLE_BITS 12
35 #define DAX_WAIT_TABLE_ENTRIES (1 << DAX_WAIT_ 35 #define DAX_WAIT_TABLE_ENTRIES (1 << DAX_WAIT_TABLE_BITS)
36 36
37 /* The 'colour' (ie low bits) within a PMD of 37 /* The 'colour' (ie low bits) within a PMD of a page offset. */
38 #define PG_PMD_COLOUR ((PMD_SIZE >> PAGE_SHI 38 #define PG_PMD_COLOUR ((PMD_SIZE >> PAGE_SHIFT) - 1)
39 #define PG_PMD_NR (PMD_SIZE >> PAGE_SHIF 39 #define PG_PMD_NR (PMD_SIZE >> PAGE_SHIFT)
40 40
41 static wait_queue_head_t wait_table[DAX_WAIT_T 41 static wait_queue_head_t wait_table[DAX_WAIT_TABLE_ENTRIES];
42 42
43 static int __init init_dax_wait_table(void) 43 static int __init init_dax_wait_table(void)
44 { 44 {
45 int i; 45 int i;
46 46
47 for (i = 0; i < DAX_WAIT_TABLE_ENTRIES 47 for (i = 0; i < DAX_WAIT_TABLE_ENTRIES; i++)
48 init_waitqueue_head(wait_table 48 init_waitqueue_head(wait_table + i);
49 return 0; 49 return 0;
50 } 50 }
51 fs_initcall(init_dax_wait_table); 51 fs_initcall(init_dax_wait_table);
52 52
53 /* 53 /*
54 * DAX pagecache entries use XArray value entr 54 * DAX pagecache entries use XArray value entries so they can't be mistaken
55 * for pages. We use one bit for locking, one 55 * for pages. We use one bit for locking, one bit for the entry size (PMD)
56 * and two more to tell us if the entry is a z 56 * and two more to tell us if the entry is a zero page or an empty entry that
57 * is just used for locking. In total four sp 57 * is just used for locking. In total four special bits.
58 * 58 *
59 * If the PMD bit isn't set the entry has size 59 * If the PMD bit isn't set the entry has size PAGE_SIZE, and if the ZERO_PAGE
60 * and EMPTY bits aren't set the entry is a no 60 * and EMPTY bits aren't set the entry is a normal DAX entry with a filesystem
61 * block allocation. 61 * block allocation.
62 */ 62 */
63 #define DAX_SHIFT (4) 63 #define DAX_SHIFT (4)
64 #define DAX_LOCKED (1UL << 0) 64 #define DAX_LOCKED (1UL << 0)
65 #define DAX_PMD (1UL << 1) 65 #define DAX_PMD (1UL << 1)
66 #define DAX_ZERO_PAGE (1UL << 2) 66 #define DAX_ZERO_PAGE (1UL << 2)
67 #define DAX_EMPTY (1UL << 3) 67 #define DAX_EMPTY (1UL << 3)
68 68
69 static unsigned long dax_to_pfn(void *entry) 69 static unsigned long dax_to_pfn(void *entry)
70 { 70 {
71 return xa_to_value(entry) >> DAX_SHIFT 71 return xa_to_value(entry) >> DAX_SHIFT;
72 } 72 }
73 73
74 static void *dax_make_entry(pfn_t pfn, unsigne 74 static void *dax_make_entry(pfn_t pfn, unsigned long flags)
75 { 75 {
76 return xa_mk_value(flags | (pfn_t_to_p 76 return xa_mk_value(flags | (pfn_t_to_pfn(pfn) << DAX_SHIFT));
77 } 77 }
78 78
79 static bool dax_is_locked(void *entry) 79 static bool dax_is_locked(void *entry)
80 { 80 {
81 return xa_to_value(entry) & DAX_LOCKED 81 return xa_to_value(entry) & DAX_LOCKED;
82 } 82 }
83 83
84 static unsigned int dax_entry_order(void *entr 84 static unsigned int dax_entry_order(void *entry)
85 { 85 {
86 if (xa_to_value(entry) & DAX_PMD) 86 if (xa_to_value(entry) & DAX_PMD)
87 return PMD_ORDER; 87 return PMD_ORDER;
88 return 0; 88 return 0;
89 } 89 }
90 90
91 static unsigned long dax_is_pmd_entry(void *en 91 static unsigned long dax_is_pmd_entry(void *entry)
92 { 92 {
93 return xa_to_value(entry) & DAX_PMD; 93 return xa_to_value(entry) & DAX_PMD;
94 } 94 }
95 95
96 static bool dax_is_pte_entry(void *entry) 96 static bool dax_is_pte_entry(void *entry)
97 { 97 {
98 return !(xa_to_value(entry) & DAX_PMD) 98 return !(xa_to_value(entry) & DAX_PMD);
99 } 99 }
100 100
101 static int dax_is_zero_entry(void *entry) 101 static int dax_is_zero_entry(void *entry)
102 { 102 {
103 return xa_to_value(entry) & DAX_ZERO_P 103 return xa_to_value(entry) & DAX_ZERO_PAGE;
104 } 104 }
105 105
106 static int dax_is_empty_entry(void *entry) 106 static int dax_is_empty_entry(void *entry)
107 { 107 {
108 return xa_to_value(entry) & DAX_EMPTY; 108 return xa_to_value(entry) & DAX_EMPTY;
109 } 109 }
110 110
111 /* 111 /*
112 * true if the entry that was found is of a sm 112 * true if the entry that was found is of a smaller order than the entry
113 * we were looking for 113 * we were looking for
114 */ 114 */
115 static bool dax_is_conflict(void *entry) 115 static bool dax_is_conflict(void *entry)
116 { 116 {
117 return entry == XA_RETRY_ENTRY; 117 return entry == XA_RETRY_ENTRY;
118 } 118 }
119 119
120 /* 120 /*
121 * DAX page cache entry locking 121 * DAX page cache entry locking
122 */ 122 */
123 struct exceptional_entry_key { 123 struct exceptional_entry_key {
124 struct xarray *xa; 124 struct xarray *xa;
125 pgoff_t entry_start; 125 pgoff_t entry_start;
126 }; 126 };
127 127
128 struct wait_exceptional_entry_queue { 128 struct wait_exceptional_entry_queue {
129 wait_queue_entry_t wait; 129 wait_queue_entry_t wait;
130 struct exceptional_entry_key key; 130 struct exceptional_entry_key key;
131 }; 131 };
132 132
133 /** 133 /**
134 * enum dax_wake_mode: waitqueue wakeup behavi 134 * enum dax_wake_mode: waitqueue wakeup behaviour
135 * @WAKE_ALL: wake all waiters in the waitqueu 135 * @WAKE_ALL: wake all waiters in the waitqueue
136 * @WAKE_NEXT: wake only the first waiter in t 136 * @WAKE_NEXT: wake only the first waiter in the waitqueue
137 */ 137 */
138 enum dax_wake_mode { 138 enum dax_wake_mode {
139 WAKE_ALL, 139 WAKE_ALL,
140 WAKE_NEXT, 140 WAKE_NEXT,
141 }; 141 };
142 142
143 static wait_queue_head_t *dax_entry_waitqueue( 143 static wait_queue_head_t *dax_entry_waitqueue(struct xa_state *xas,
144 void *entry, struct exceptiona 144 void *entry, struct exceptional_entry_key *key)
145 { 145 {
146 unsigned long hash; 146 unsigned long hash;
147 unsigned long index = xas->xa_index; 147 unsigned long index = xas->xa_index;
148 148
149 /* 149 /*
150 * If 'entry' is a PMD, align the 'ind 150 * If 'entry' is a PMD, align the 'index' that we use for the wait
151 * queue to the start of that PMD. Th 151 * queue to the start of that PMD. This ensures that all offsets in
152 * the range covered by the PMD map to 152 * the range covered by the PMD map to the same bit lock.
153 */ 153 */
154 if (dax_is_pmd_entry(entry)) 154 if (dax_is_pmd_entry(entry))
155 index &= ~PG_PMD_COLOUR; 155 index &= ~PG_PMD_COLOUR;
156 key->xa = xas->xa; 156 key->xa = xas->xa;
157 key->entry_start = index; 157 key->entry_start = index;
158 158
159 hash = hash_long((unsigned long)xas->x 159 hash = hash_long((unsigned long)xas->xa ^ index, DAX_WAIT_TABLE_BITS);
160 return wait_table + hash; 160 return wait_table + hash;
161 } 161 }
162 162
163 static int wake_exceptional_entry_func(wait_qu 163 static int wake_exceptional_entry_func(wait_queue_entry_t *wait,
164 unsigned int mode, int sync, v 164 unsigned int mode, int sync, void *keyp)
165 { 165 {
166 struct exceptional_entry_key *key = ke 166 struct exceptional_entry_key *key = keyp;
167 struct wait_exceptional_entry_queue *e 167 struct wait_exceptional_entry_queue *ewait =
168 container_of(wait, struct wait 168 container_of(wait, struct wait_exceptional_entry_queue, wait);
169 169
170 if (key->xa != ewait->key.xa || 170 if (key->xa != ewait->key.xa ||
171 key->entry_start != ewait->key.ent 171 key->entry_start != ewait->key.entry_start)
172 return 0; 172 return 0;
173 return autoremove_wake_function(wait, 173 return autoremove_wake_function(wait, mode, sync, NULL);
174 } 174 }
175 175
176 /* 176 /*
177 * @entry may no longer be the entry at the in 177 * @entry may no longer be the entry at the index in the mapping.
178 * The important information it's conveying is 178 * The important information it's conveying is whether the entry at
179 * this index used to be a PMD entry. 179 * this index used to be a PMD entry.
180 */ 180 */
181 static void dax_wake_entry(struct xa_state *xa 181 static void dax_wake_entry(struct xa_state *xas, void *entry,
182 enum dax_wake_mode 182 enum dax_wake_mode mode)
183 { 183 {
184 struct exceptional_entry_key key; 184 struct exceptional_entry_key key;
185 wait_queue_head_t *wq; 185 wait_queue_head_t *wq;
186 186
187 wq = dax_entry_waitqueue(xas, entry, & 187 wq = dax_entry_waitqueue(xas, entry, &key);
188 188
189 /* 189 /*
190 * Checking for locked entry and prepa 190 * Checking for locked entry and prepare_to_wait_exclusive() happens
191 * under the i_pages lock, ditto for e 191 * under the i_pages lock, ditto for entry handling in our callers.
192 * So at this point all tasks that cou 192 * So at this point all tasks that could have seen our entry locked
193 * must be in the waitqueue and the fo 193 * must be in the waitqueue and the following check will see them.
194 */ 194 */
195 if (waitqueue_active(wq)) 195 if (waitqueue_active(wq))
196 __wake_up(wq, TASK_NORMAL, mod 196 __wake_up(wq, TASK_NORMAL, mode == WAKE_ALL ? 0 : 1, &key);
197 } 197 }
198 198
199 /* 199 /*
200 * Look up entry in page cache, wait for it to 200 * Look up entry in page cache, wait for it to become unlocked if it
201 * is a DAX entry and return it. The caller m 201 * is a DAX entry and return it. The caller must subsequently call
202 * put_unlocked_entry() if it did not lock the 202 * put_unlocked_entry() if it did not lock the entry or dax_unlock_entry()
203 * if it did. The entry returned may have a l 203 * if it did. The entry returned may have a larger order than @order.
204 * If @order is larger than the order of the e 204 * If @order is larger than the order of the entry found in i_pages, this
205 * function returns a dax_is_conflict entry. 205 * function returns a dax_is_conflict entry.
206 * 206 *
207 * Must be called with the i_pages lock held. 207 * Must be called with the i_pages lock held.
208 */ 208 */
209 static void *get_unlocked_entry(struct xa_stat 209 static void *get_unlocked_entry(struct xa_state *xas, unsigned int order)
210 { 210 {
211 void *entry; 211 void *entry;
212 struct wait_exceptional_entry_queue ew 212 struct wait_exceptional_entry_queue ewait;
213 wait_queue_head_t *wq; 213 wait_queue_head_t *wq;
214 214
215 init_wait(&ewait.wait); 215 init_wait(&ewait.wait);
216 ewait.wait.func = wake_exceptional_ent 216 ewait.wait.func = wake_exceptional_entry_func;
217 217
218 for (;;) { 218 for (;;) {
219 entry = xas_find_conflict(xas) 219 entry = xas_find_conflict(xas);
220 if (!entry || WARN_ON_ONCE(!xa 220 if (!entry || WARN_ON_ONCE(!xa_is_value(entry)))
221 return entry; 221 return entry;
222 if (dax_entry_order(entry) < o 222 if (dax_entry_order(entry) < order)
223 return XA_RETRY_ENTRY; 223 return XA_RETRY_ENTRY;
224 if (!dax_is_locked(entry)) 224 if (!dax_is_locked(entry))
225 return entry; 225 return entry;
226 226
227 wq = dax_entry_waitqueue(xas, 227 wq = dax_entry_waitqueue(xas, entry, &ewait.key);
228 prepare_to_wait_exclusive(wq, 228 prepare_to_wait_exclusive(wq, &ewait.wait,
229 TASK 229 TASK_UNINTERRUPTIBLE);
230 xas_unlock_irq(xas); 230 xas_unlock_irq(xas);
231 xas_reset(xas); 231 xas_reset(xas);
232 schedule(); 232 schedule();
233 finish_wait(wq, &ewait.wait); 233 finish_wait(wq, &ewait.wait);
234 xas_lock_irq(xas); 234 xas_lock_irq(xas);
235 } 235 }
236 } 236 }
237 237
238 /* 238 /*
239 * The only thing keeping the address space ar 239 * The only thing keeping the address space around is the i_pages lock
240 * (it's cycled in clear_inode() after removin 240 * (it's cycled in clear_inode() after removing the entries from i_pages)
241 * After we call xas_unlock_irq(), we cannot t 241 * After we call xas_unlock_irq(), we cannot touch xas->xa.
242 */ 242 */
243 static void wait_entry_unlocked(struct xa_stat 243 static void wait_entry_unlocked(struct xa_state *xas, void *entry)
244 { 244 {
245 struct wait_exceptional_entry_queue ew 245 struct wait_exceptional_entry_queue ewait;
246 wait_queue_head_t *wq; 246 wait_queue_head_t *wq;
247 247
248 init_wait(&ewait.wait); 248 init_wait(&ewait.wait);
249 ewait.wait.func = wake_exceptional_ent 249 ewait.wait.func = wake_exceptional_entry_func;
250 250
251 wq = dax_entry_waitqueue(xas, entry, & 251 wq = dax_entry_waitqueue(xas, entry, &ewait.key);
252 /* 252 /*
253 * Unlike get_unlocked_entry() there i 253 * Unlike get_unlocked_entry() there is no guarantee that this
254 * path ever successfully retrieves an 254 * path ever successfully retrieves an unlocked entry before an
255 * inode dies. Perform a non-exclusive 255 * inode dies. Perform a non-exclusive wait in case this path
256 * never successfully performs its own 256 * never successfully performs its own wake up.
257 */ 257 */
258 prepare_to_wait(wq, &ewait.wait, TASK_ 258 prepare_to_wait(wq, &ewait.wait, TASK_UNINTERRUPTIBLE);
259 xas_unlock_irq(xas); 259 xas_unlock_irq(xas);
260 schedule(); 260 schedule();
261 finish_wait(wq, &ewait.wait); 261 finish_wait(wq, &ewait.wait);
262 } 262 }
263 263
264 static void put_unlocked_entry(struct xa_state 264 static void put_unlocked_entry(struct xa_state *xas, void *entry,
265 enum dax_wake_m 265 enum dax_wake_mode mode)
266 { 266 {
267 if (entry && !dax_is_conflict(entry)) 267 if (entry && !dax_is_conflict(entry))
268 dax_wake_entry(xas, entry, mod 268 dax_wake_entry(xas, entry, mode);
269 } 269 }
270 270
271 /* 271 /*
272 * We used the xa_state to get the entry, but 272 * We used the xa_state to get the entry, but then we locked the entry and
273 * dropped the xa_lock, so we know the xa_stat 273 * dropped the xa_lock, so we know the xa_state is stale and must be reset
274 * before use. 274 * before use.
275 */ 275 */
276 static void dax_unlock_entry(struct xa_state * 276 static void dax_unlock_entry(struct xa_state *xas, void *entry)
277 { 277 {
278 void *old; 278 void *old;
279 279
280 BUG_ON(dax_is_locked(entry)); 280 BUG_ON(dax_is_locked(entry));
281 xas_reset(xas); 281 xas_reset(xas);
282 xas_lock_irq(xas); 282 xas_lock_irq(xas);
283 old = xas_store(xas, entry); 283 old = xas_store(xas, entry);
284 xas_unlock_irq(xas); 284 xas_unlock_irq(xas);
285 BUG_ON(!dax_is_locked(old)); 285 BUG_ON(!dax_is_locked(old));
286 dax_wake_entry(xas, entry, WAKE_NEXT); 286 dax_wake_entry(xas, entry, WAKE_NEXT);
287 } 287 }
288 288
289 /* 289 /*
290 * Return: The entry stored at this location b 290 * Return: The entry stored at this location before it was locked.
291 */ 291 */
292 static void *dax_lock_entry(struct xa_state *x 292 static void *dax_lock_entry(struct xa_state *xas, void *entry)
293 { 293 {
294 unsigned long v = xa_to_value(entry); 294 unsigned long v = xa_to_value(entry);
295 return xas_store(xas, xa_mk_value(v | 295 return xas_store(xas, xa_mk_value(v | DAX_LOCKED));
296 } 296 }
297 297
298 static unsigned long dax_entry_size(void *entr 298 static unsigned long dax_entry_size(void *entry)
299 { 299 {
300 if (dax_is_zero_entry(entry)) 300 if (dax_is_zero_entry(entry))
301 return 0; 301 return 0;
302 else if (dax_is_empty_entry(entry)) 302 else if (dax_is_empty_entry(entry))
303 return 0; 303 return 0;
304 else if (dax_is_pmd_entry(entry)) 304 else if (dax_is_pmd_entry(entry))
305 return PMD_SIZE; 305 return PMD_SIZE;
306 else 306 else
307 return PAGE_SIZE; 307 return PAGE_SIZE;
308 } 308 }
309 309
310 static unsigned long dax_end_pfn(void *entry) 310 static unsigned long dax_end_pfn(void *entry)
311 { 311 {
312 return dax_to_pfn(entry) + dax_entry_s 312 return dax_to_pfn(entry) + dax_entry_size(entry) / PAGE_SIZE;
313 } 313 }
314 314
315 /* 315 /*
316 * Iterate through all mapped pfns represented 316 * Iterate through all mapped pfns represented by an entry, i.e. skip
317 * 'empty' and 'zero' entries. 317 * 'empty' and 'zero' entries.
318 */ 318 */
319 #define for_each_mapped_pfn(entry, pfn) \ 319 #define for_each_mapped_pfn(entry, pfn) \
320 for (pfn = dax_to_pfn(entry); \ 320 for (pfn = dax_to_pfn(entry); \
321 pfn < dax_end_pfn(entr 321 pfn < dax_end_pfn(entry); pfn++)
322 322
323 static inline bool dax_page_is_shared(struct p 323 static inline bool dax_page_is_shared(struct page *page)
324 { 324 {
325 return page->mapping == PAGE_MAPPING_D 325 return page->mapping == PAGE_MAPPING_DAX_SHARED;
326 } 326 }
327 327
328 /* 328 /*
329 * Set the page->mapping with PAGE_MAPPING_DAX 329 * Set the page->mapping with PAGE_MAPPING_DAX_SHARED flag, increase the
330 * refcount. 330 * refcount.
331 */ 331 */
332 static inline void dax_page_share_get(struct p 332 static inline void dax_page_share_get(struct page *page)
333 { 333 {
334 if (page->mapping != PAGE_MAPPING_DAX_ 334 if (page->mapping != PAGE_MAPPING_DAX_SHARED) {
335 /* 335 /*
336 * Reset the index if the page 336 * Reset the index if the page was already mapped
337 * regularly before. 337 * regularly before.
338 */ 338 */
339 if (page->mapping) 339 if (page->mapping)
340 page->share = 1; 340 page->share = 1;
341 page->mapping = PAGE_MAPPING_D 341 page->mapping = PAGE_MAPPING_DAX_SHARED;
342 } 342 }
343 page->share++; 343 page->share++;
344 } 344 }
345 345
346 static inline unsigned long dax_page_share_put 346 static inline unsigned long dax_page_share_put(struct page *page)
347 { 347 {
348 return --page->share; 348 return --page->share;
349 } 349 }
350 350
351 /* 351 /*
352 * When it is called in dax_insert_entry(), th 352 * When it is called in dax_insert_entry(), the shared flag will indicate that
353 * whether this entry is shared by multiple fi 353 * whether this entry is shared by multiple files. If so, set the page->mapping
354 * PAGE_MAPPING_DAX_SHARED, and use page->shar 354 * PAGE_MAPPING_DAX_SHARED, and use page->share as refcount.
355 */ 355 */
356 static void dax_associate_entry(void *entry, s 356 static void dax_associate_entry(void *entry, struct address_space *mapping,
357 struct vm_area_struct *vma, un 357 struct vm_area_struct *vma, unsigned long address, bool shared)
358 { 358 {
359 unsigned long size = dax_entry_size(en 359 unsigned long size = dax_entry_size(entry), pfn, index;
360 int i = 0; 360 int i = 0;
361 361
362 if (IS_ENABLED(CONFIG_FS_DAX_LIMITED)) 362 if (IS_ENABLED(CONFIG_FS_DAX_LIMITED))
363 return; 363 return;
364 364
365 index = linear_page_index(vma, address 365 index = linear_page_index(vma, address & ~(size - 1));
366 for_each_mapped_pfn(entry, pfn) { 366 for_each_mapped_pfn(entry, pfn) {
367 struct page *page = pfn_to_pag 367 struct page *page = pfn_to_page(pfn);
368 368
369 if (shared) { 369 if (shared) {
370 dax_page_share_get(pag 370 dax_page_share_get(page);
371 } else { 371 } else {
372 WARN_ON_ONCE(page->map 372 WARN_ON_ONCE(page->mapping);
373 page->mapping = mappin 373 page->mapping = mapping;
374 page->index = index + 374 page->index = index + i++;
375 } 375 }
376 } 376 }
377 } 377 }
378 378
379 static void dax_disassociate_entry(void *entry 379 static void dax_disassociate_entry(void *entry, struct address_space *mapping,
380 bool trunc) 380 bool trunc)
381 { 381 {
382 unsigned long pfn; 382 unsigned long pfn;
383 383
384 if (IS_ENABLED(CONFIG_FS_DAX_LIMITED)) 384 if (IS_ENABLED(CONFIG_FS_DAX_LIMITED))
385 return; 385 return;
386 386
387 for_each_mapped_pfn(entry, pfn) { 387 for_each_mapped_pfn(entry, pfn) {
388 struct page *page = pfn_to_pag 388 struct page *page = pfn_to_page(pfn);
389 389
390 WARN_ON_ONCE(trunc && page_ref 390 WARN_ON_ONCE(trunc && page_ref_count(page) > 1);
391 if (dax_page_is_shared(page)) 391 if (dax_page_is_shared(page)) {
392 /* keep the shared fla 392 /* keep the shared flag if this page is still shared */
393 if (dax_page_share_put 393 if (dax_page_share_put(page) > 0)
394 continue; 394 continue;
395 } else 395 } else
396 WARN_ON_ONCE(page->map 396 WARN_ON_ONCE(page->mapping && page->mapping != mapping);
397 page->mapping = NULL; 397 page->mapping = NULL;
398 page->index = 0; 398 page->index = 0;
399 } 399 }
400 } 400 }
401 401
402 static struct page *dax_busy_page(void *entry) 402 static struct page *dax_busy_page(void *entry)
403 { 403 {
404 unsigned long pfn; 404 unsigned long pfn;
405 405
406 for_each_mapped_pfn(entry, pfn) { 406 for_each_mapped_pfn(entry, pfn) {
407 struct page *page = pfn_to_pag 407 struct page *page = pfn_to_page(pfn);
408 408
409 if (page_ref_count(page) > 1) 409 if (page_ref_count(page) > 1)
410 return page; 410 return page;
411 } 411 }
412 return NULL; 412 return NULL;
413 } 413 }
414 414
415 /** 415 /**
416 * dax_lock_folio - Lock the DAX entry corresp 416 * dax_lock_folio - Lock the DAX entry corresponding to a folio
417 * @folio: The folio whose entry we want to lo 417 * @folio: The folio whose entry we want to lock
418 * 418 *
419 * Context: Process context. 419 * Context: Process context.
420 * Return: A cookie to pass to dax_unlock_foli 420 * Return: A cookie to pass to dax_unlock_folio() or 0 if the entry could
421 * not be locked. 421 * not be locked.
422 */ 422 */
423 dax_entry_t dax_lock_folio(struct folio *folio 423 dax_entry_t dax_lock_folio(struct folio *folio)
424 { 424 {
425 XA_STATE(xas, NULL, 0); 425 XA_STATE(xas, NULL, 0);
426 void *entry; 426 void *entry;
427 427
428 /* Ensure folio->mapping isn't freed w 428 /* Ensure folio->mapping isn't freed while we look at it */
429 rcu_read_lock(); 429 rcu_read_lock();
430 for (;;) { 430 for (;;) {
431 struct address_space *mapping 431 struct address_space *mapping = READ_ONCE(folio->mapping);
432 432
433 entry = NULL; 433 entry = NULL;
434 if (!mapping || !dax_mapping(m 434 if (!mapping || !dax_mapping(mapping))
435 break; 435 break;
436 436
437 /* 437 /*
438 * In the device-dax case ther 438 * In the device-dax case there's no need to lock, a
439 * struct dev_pagemap pin is s 439 * struct dev_pagemap pin is sufficient to keep the
440 * inode alive, and we assume 440 * inode alive, and we assume we have dev_pagemap pin
441 * otherwise we would not have 441 * otherwise we would not have a valid pfn_to_page()
442 * translation. 442 * translation.
443 */ 443 */
444 entry = (void *)~0UL; 444 entry = (void *)~0UL;
445 if (S_ISCHR(mapping->host->i_m 445 if (S_ISCHR(mapping->host->i_mode))
446 break; 446 break;
447 447
448 xas.xa = &mapping->i_pages; 448 xas.xa = &mapping->i_pages;
449 xas_lock_irq(&xas); 449 xas_lock_irq(&xas);
450 if (mapping != folio->mapping) 450 if (mapping != folio->mapping) {
451 xas_unlock_irq(&xas); 451 xas_unlock_irq(&xas);
452 continue; 452 continue;
453 } 453 }
454 xas_set(&xas, folio->index); 454 xas_set(&xas, folio->index);
455 entry = xas_load(&xas); 455 entry = xas_load(&xas);
456 if (dax_is_locked(entry)) { 456 if (dax_is_locked(entry)) {
457 rcu_read_unlock(); 457 rcu_read_unlock();
458 wait_entry_unlocked(&x 458 wait_entry_unlocked(&xas, entry);
459 rcu_read_lock(); 459 rcu_read_lock();
460 continue; 460 continue;
461 } 461 }
462 dax_lock_entry(&xas, entry); 462 dax_lock_entry(&xas, entry);
463 xas_unlock_irq(&xas); 463 xas_unlock_irq(&xas);
464 break; 464 break;
465 } 465 }
466 rcu_read_unlock(); 466 rcu_read_unlock();
467 return (dax_entry_t)entry; 467 return (dax_entry_t)entry;
468 } 468 }
469 469
470 void dax_unlock_folio(struct folio *folio, dax 470 void dax_unlock_folio(struct folio *folio, dax_entry_t cookie)
471 { 471 {
472 struct address_space *mapping = folio- 472 struct address_space *mapping = folio->mapping;
473 XA_STATE(xas, &mapping->i_pages, folio 473 XA_STATE(xas, &mapping->i_pages, folio->index);
474 474
475 if (S_ISCHR(mapping->host->i_mode)) 475 if (S_ISCHR(mapping->host->i_mode))
476 return; 476 return;
477 477
478 dax_unlock_entry(&xas, (void *)cookie) 478 dax_unlock_entry(&xas, (void *)cookie);
479 } 479 }
480 480
481 /* 481 /*
482 * dax_lock_mapping_entry - Lock the DAX entry 482 * dax_lock_mapping_entry - Lock the DAX entry corresponding to a mapping
483 * @mapping: the file's mapping whose entry we 483 * @mapping: the file's mapping whose entry we want to lock
484 * @index: the offset within this file 484 * @index: the offset within this file
485 * @page: output the dax page corresponding to 485 * @page: output the dax page corresponding to this dax entry
486 * 486 *
487 * Return: A cookie to pass to dax_unlock_mapp 487 * Return: A cookie to pass to dax_unlock_mapping_entry() or 0 if the entry
488 * could not be locked. 488 * could not be locked.
489 */ 489 */
490 dax_entry_t dax_lock_mapping_entry(struct addr 490 dax_entry_t dax_lock_mapping_entry(struct address_space *mapping, pgoff_t index,
491 struct page **page) 491 struct page **page)
492 { 492 {
493 XA_STATE(xas, NULL, 0); 493 XA_STATE(xas, NULL, 0);
494 void *entry; 494 void *entry;
495 495
496 rcu_read_lock(); 496 rcu_read_lock();
497 for (;;) { 497 for (;;) {
498 entry = NULL; 498 entry = NULL;
499 if (!dax_mapping(mapping)) 499 if (!dax_mapping(mapping))
500 break; 500 break;
501 501
502 xas.xa = &mapping->i_pages; 502 xas.xa = &mapping->i_pages;
503 xas_lock_irq(&xas); 503 xas_lock_irq(&xas);
504 xas_set(&xas, index); 504 xas_set(&xas, index);
505 entry = xas_load(&xas); 505 entry = xas_load(&xas);
506 if (dax_is_locked(entry)) { 506 if (dax_is_locked(entry)) {
507 rcu_read_unlock(); 507 rcu_read_unlock();
508 wait_entry_unlocked(&x 508 wait_entry_unlocked(&xas, entry);
509 rcu_read_lock(); 509 rcu_read_lock();
510 continue; 510 continue;
511 } 511 }
512 if (!entry || 512 if (!entry ||
513 dax_is_zero_entry(entry) | 513 dax_is_zero_entry(entry) || dax_is_empty_entry(entry)) {
514 /* 514 /*
515 * Because we are look 515 * Because we are looking for entry from file's mapping
516 * and index, so the e 516 * and index, so the entry may not be inserted for now,
517 * or even a zero/empt 517 * or even a zero/empty entry. We don't think this is
518 * an error case. So, 518 * an error case. So, return a special value and do
519 * not output @page. 519 * not output @page.
520 */ 520 */
521 entry = (void *)~0UL; 521 entry = (void *)~0UL;
522 } else { 522 } else {
523 *page = pfn_to_page(da 523 *page = pfn_to_page(dax_to_pfn(entry));
524 dax_lock_entry(&xas, e 524 dax_lock_entry(&xas, entry);
525 } 525 }
526 xas_unlock_irq(&xas); 526 xas_unlock_irq(&xas);
527 break; 527 break;
528 } 528 }
529 rcu_read_unlock(); 529 rcu_read_unlock();
530 return (dax_entry_t)entry; 530 return (dax_entry_t)entry;
531 } 531 }
532 532
533 void dax_unlock_mapping_entry(struct address_s 533 void dax_unlock_mapping_entry(struct address_space *mapping, pgoff_t index,
534 dax_entry_t cookie) 534 dax_entry_t cookie)
535 { 535 {
536 XA_STATE(xas, &mapping->i_pages, index 536 XA_STATE(xas, &mapping->i_pages, index);
537 537
538 if (cookie == ~0UL) 538 if (cookie == ~0UL)
539 return; 539 return;
540 540
541 dax_unlock_entry(&xas, (void *)cookie) 541 dax_unlock_entry(&xas, (void *)cookie);
542 } 542 }
543 543
544 /* 544 /*
545 * Find page cache entry at given index. If it 545 * Find page cache entry at given index. If it is a DAX entry, return it
546 * with the entry locked. If the page cache do 546 * with the entry locked. If the page cache doesn't contain an entry at
547 * that index, add a locked empty entry. 547 * that index, add a locked empty entry.
548 * 548 *
549 * When requesting an entry with size DAX_PMD, 549 * When requesting an entry with size DAX_PMD, grab_mapping_entry() will
550 * either return that locked entry or will ret 550 * either return that locked entry or will return VM_FAULT_FALLBACK.
551 * This will happen if there are any PTE entri 551 * This will happen if there are any PTE entries within the PMD range
552 * that we are requesting. 552 * that we are requesting.
553 * 553 *
554 * We always favor PTE entries over PMD entrie 554 * We always favor PTE entries over PMD entries. There isn't a flow where we
555 * evict PTE entries in order to 'upgrade' the 555 * evict PTE entries in order to 'upgrade' them to a PMD entry. A PMD
556 * insertion will fail if it finds any PTE ent 556 * insertion will fail if it finds any PTE entries already in the tree, and a
557 * PTE insertion will cause an existing PMD en 557 * PTE insertion will cause an existing PMD entry to be unmapped and
558 * downgraded to PTE entries. This happens fo 558 * downgraded to PTE entries. This happens for both PMD zero pages as
559 * well as PMD empty entries. 559 * well as PMD empty entries.
560 * 560 *
561 * The exception to this downgrade path is for 561 * The exception to this downgrade path is for PMD entries that have
562 * real storage backing them. We will leave t 562 * real storage backing them. We will leave these real PMD entries in
563 * the tree, and PTE writes will simply dirty 563 * the tree, and PTE writes will simply dirty the entire PMD entry.
564 * 564 *
565 * Note: Unlike filemap_fault() we don't honor 565 * Note: Unlike filemap_fault() we don't honor FAULT_FLAG_RETRY flags. For
566 * persistent memory the benefit is doubtful. 566 * persistent memory the benefit is doubtful. We can add that later if we can
567 * show it helps. 567 * show it helps.
568 * 568 *
569 * On error, this function does not return an 569 * On error, this function does not return an ERR_PTR. Instead it returns
570 * a VM_FAULT code, encoded as an xarray inter 570 * a VM_FAULT code, encoded as an xarray internal entry. The ERR_PTR values
571 * overlap with xarray value entries. 571 * overlap with xarray value entries.
572 */ 572 */
573 static void *grab_mapping_entry(struct xa_stat 573 static void *grab_mapping_entry(struct xa_state *xas,
574 struct address_space *mapping, 574 struct address_space *mapping, unsigned int order)
575 { 575 {
576 unsigned long index = xas->xa_index; 576 unsigned long index = xas->xa_index;
577 bool pmd_downgrade; /* splitting P 577 bool pmd_downgrade; /* splitting PMD entry into PTE entries? */
578 void *entry; 578 void *entry;
579 579
580 retry: 580 retry:
581 pmd_downgrade = false; 581 pmd_downgrade = false;
582 xas_lock_irq(xas); 582 xas_lock_irq(xas);
583 entry = get_unlocked_entry(xas, order) 583 entry = get_unlocked_entry(xas, order);
584 584
585 if (entry) { 585 if (entry) {
586 if (dax_is_conflict(entry)) 586 if (dax_is_conflict(entry))
587 goto fallback; 587 goto fallback;
588 if (!xa_is_value(entry)) { 588 if (!xa_is_value(entry)) {
589 xas_set_err(xas, -EIO) 589 xas_set_err(xas, -EIO);
590 goto out_unlock; 590 goto out_unlock;
591 } 591 }
592 592
593 if (order == 0) { 593 if (order == 0) {
594 if (dax_is_pmd_entry(e 594 if (dax_is_pmd_entry(entry) &&
595 (dax_is_zero_entry 595 (dax_is_zero_entry(entry) ||
596 dax_is_empty_entr 596 dax_is_empty_entry(entry))) {
597 pmd_downgrade 597 pmd_downgrade = true;
598 } 598 }
599 } 599 }
600 } 600 }
601 601
602 if (pmd_downgrade) { 602 if (pmd_downgrade) {
603 /* 603 /*
604 * Make sure 'entry' remains v 604 * Make sure 'entry' remains valid while we drop
605 * the i_pages lock. 605 * the i_pages lock.
606 */ 606 */
607 dax_lock_entry(xas, entry); 607 dax_lock_entry(xas, entry);
608 608
609 /* 609 /*
610 * Besides huge zero pages the 610 * Besides huge zero pages the only other thing that gets
611 * downgraded are empty entrie 611 * downgraded are empty entries which don't need to be
612 * unmapped. 612 * unmapped.
613 */ 613 */
614 if (dax_is_zero_entry(entry)) 614 if (dax_is_zero_entry(entry)) {
615 xas_unlock_irq(xas); 615 xas_unlock_irq(xas);
616 unmap_mapping_pages(ma 616 unmap_mapping_pages(mapping,
617 xas->x 617 xas->xa_index & ~PG_PMD_COLOUR,
618 PG_PMD 618 PG_PMD_NR, false);
619 xas_reset(xas); 619 xas_reset(xas);
620 xas_lock_irq(xas); 620 xas_lock_irq(xas);
621 } 621 }
622 622
623 dax_disassociate_entry(entry, 623 dax_disassociate_entry(entry, mapping, false);
624 xas_store(xas, NULL); /* und 624 xas_store(xas, NULL); /* undo the PMD join */
625 dax_wake_entry(xas, entry, WAK 625 dax_wake_entry(xas, entry, WAKE_ALL);
626 mapping->nrpages -= PG_PMD_NR; 626 mapping->nrpages -= PG_PMD_NR;
627 entry = NULL; 627 entry = NULL;
628 xas_set(xas, index); 628 xas_set(xas, index);
629 } 629 }
630 630
631 if (entry) { 631 if (entry) {
632 dax_lock_entry(xas, entry); 632 dax_lock_entry(xas, entry);
633 } else { 633 } else {
634 unsigned long flags = DAX_EMPT 634 unsigned long flags = DAX_EMPTY;
635 635
636 if (order > 0) 636 if (order > 0)
637 flags |= DAX_PMD; 637 flags |= DAX_PMD;
638 entry = dax_make_entry(pfn_to_ 638 entry = dax_make_entry(pfn_to_pfn_t(0), flags);
639 dax_lock_entry(xas, entry); 639 dax_lock_entry(xas, entry);
640 if (xas_error(xas)) 640 if (xas_error(xas))
641 goto out_unlock; 641 goto out_unlock;
642 mapping->nrpages += 1UL << ord 642 mapping->nrpages += 1UL << order;
643 } 643 }
644 644
645 out_unlock: 645 out_unlock:
646 xas_unlock_irq(xas); 646 xas_unlock_irq(xas);
647 if (xas_nomem(xas, mapping_gfp_mask(ma 647 if (xas_nomem(xas, mapping_gfp_mask(mapping) & ~__GFP_HIGHMEM))
648 goto retry; 648 goto retry;
649 if (xas->xa_node == XA_ERROR(-ENOMEM)) 649 if (xas->xa_node == XA_ERROR(-ENOMEM))
650 return xa_mk_internal(VM_FAULT 650 return xa_mk_internal(VM_FAULT_OOM);
651 if (xas_error(xas)) 651 if (xas_error(xas))
652 return xa_mk_internal(VM_FAULT 652 return xa_mk_internal(VM_FAULT_SIGBUS);
653 return entry; 653 return entry;
654 fallback: 654 fallback:
655 xas_unlock_irq(xas); 655 xas_unlock_irq(xas);
656 return xa_mk_internal(VM_FAULT_FALLBAC 656 return xa_mk_internal(VM_FAULT_FALLBACK);
657 } 657 }
658 658
659 /** 659 /**
660 * dax_layout_busy_page_range - find first pin 660 * dax_layout_busy_page_range - find first pinned page in @mapping
661 * @mapping: address space to scan for a page 661 * @mapping: address space to scan for a page with ref count > 1
662 * @start: Starting offset. Page containing 's 662 * @start: Starting offset. Page containing 'start' is included.
663 * @end: End offset. Page containing 'end' is 663 * @end: End offset. Page containing 'end' is included. If 'end' is LLONG_MAX,
664 * pages from 'start' till the end of fi 664 * pages from 'start' till the end of file are included.
665 * 665 *
666 * DAX requires ZONE_DEVICE mapped pages. Thes 666 * DAX requires ZONE_DEVICE mapped pages. These pages are never
667 * 'onlined' to the page allocator so they are 667 * 'onlined' to the page allocator so they are considered idle when
668 * page->count == 1. A filesystem uses this in 668 * page->count == 1. A filesystem uses this interface to determine if
669 * any page in the mapping is busy, i.e. for D 669 * any page in the mapping is busy, i.e. for DMA, or other
670 * get_user_pages() usages. 670 * get_user_pages() usages.
671 * 671 *
672 * It is expected that the filesystem is holdi 672 * It is expected that the filesystem is holding locks to block the
673 * establishment of new mappings in this addre 673 * establishment of new mappings in this address_space. I.e. it expects
674 * to be able to run unmap_mapping_range() and 674 * to be able to run unmap_mapping_range() and subsequently not race
675 * mapping_mapped() becoming true. 675 * mapping_mapped() becoming true.
676 */ 676 */
677 struct page *dax_layout_busy_page_range(struct 677 struct page *dax_layout_busy_page_range(struct address_space *mapping,
678 loff_t 678 loff_t start, loff_t end)
679 { 679 {
680 void *entry; 680 void *entry;
681 unsigned int scanned = 0; 681 unsigned int scanned = 0;
682 struct page *page = NULL; 682 struct page *page = NULL;
683 pgoff_t start_idx = start >> PAGE_SHIF 683 pgoff_t start_idx = start >> PAGE_SHIFT;
684 pgoff_t end_idx; 684 pgoff_t end_idx;
685 XA_STATE(xas, &mapping->i_pages, start 685 XA_STATE(xas, &mapping->i_pages, start_idx);
686 686
687 /* 687 /*
688 * In the 'limited' case get_user_page 688 * In the 'limited' case get_user_pages() for dax is disabled.
689 */ 689 */
690 if (IS_ENABLED(CONFIG_FS_DAX_LIMITED)) 690 if (IS_ENABLED(CONFIG_FS_DAX_LIMITED))
691 return NULL; 691 return NULL;
692 692
693 if (!dax_mapping(mapping) || !mapping_ 693 if (!dax_mapping(mapping) || !mapping_mapped(mapping))
694 return NULL; 694 return NULL;
695 695
696 /* If end == LLONG_MAX, all pages from 696 /* If end == LLONG_MAX, all pages from start to till end of file */
697 if (end == LLONG_MAX) 697 if (end == LLONG_MAX)
698 end_idx = ULONG_MAX; 698 end_idx = ULONG_MAX;
699 else 699 else
700 end_idx = end >> PAGE_SHIFT; 700 end_idx = end >> PAGE_SHIFT;
701 /* 701 /*
702 * If we race get_user_pages_fast() he 702 * If we race get_user_pages_fast() here either we'll see the
703 * elevated page count in the iteratio 703 * elevated page count in the iteration and wait, or
704 * get_user_pages_fast() will see that 704 * get_user_pages_fast() will see that the page it took a reference
705 * against is no longer mapped in the 705 * against is no longer mapped in the page tables and bail to the
706 * get_user_pages() slow path. The sl 706 * get_user_pages() slow path. The slow path is protected by
707 * pte_lock() and pmd_lock(). New refe 707 * pte_lock() and pmd_lock(). New references are not taken without
708 * holding those locks, and unmap_mapp 708 * holding those locks, and unmap_mapping_pages() will not zero the
709 * pte or pmd without holding the resp 709 * pte or pmd without holding the respective lock, so we are
710 * guaranteed to either see new refere 710 * guaranteed to either see new references or prevent new
711 * references from being established. 711 * references from being established.
712 */ 712 */
713 unmap_mapping_pages(mapping, start_idx 713 unmap_mapping_pages(mapping, start_idx, end_idx - start_idx + 1, 0);
714 714
715 xas_lock_irq(&xas); 715 xas_lock_irq(&xas);
716 xas_for_each(&xas, entry, end_idx) { 716 xas_for_each(&xas, entry, end_idx) {
717 if (WARN_ON_ONCE(!xa_is_value( 717 if (WARN_ON_ONCE(!xa_is_value(entry)))
718 continue; 718 continue;
719 if (unlikely(dax_is_locked(ent 719 if (unlikely(dax_is_locked(entry)))
720 entry = get_unlocked_e 720 entry = get_unlocked_entry(&xas, 0);
721 if (entry) 721 if (entry)
722 page = dax_busy_page(e 722 page = dax_busy_page(entry);
723 put_unlocked_entry(&xas, entry 723 put_unlocked_entry(&xas, entry, WAKE_NEXT);
724 if (page) 724 if (page)
725 break; 725 break;
726 if (++scanned % XA_CHECK_SCHED 726 if (++scanned % XA_CHECK_SCHED)
727 continue; 727 continue;
728 728
729 xas_pause(&xas); 729 xas_pause(&xas);
730 xas_unlock_irq(&xas); 730 xas_unlock_irq(&xas);
731 cond_resched(); 731 cond_resched();
732 xas_lock_irq(&xas); 732 xas_lock_irq(&xas);
733 } 733 }
734 xas_unlock_irq(&xas); 734 xas_unlock_irq(&xas);
735 return page; 735 return page;
736 } 736 }
737 EXPORT_SYMBOL_GPL(dax_layout_busy_page_range); 737 EXPORT_SYMBOL_GPL(dax_layout_busy_page_range);
738 738
739 struct page *dax_layout_busy_page(struct addre 739 struct page *dax_layout_busy_page(struct address_space *mapping)
740 { 740 {
741 return dax_layout_busy_page_range(mapp 741 return dax_layout_busy_page_range(mapping, 0, LLONG_MAX);
742 } 742 }
743 EXPORT_SYMBOL_GPL(dax_layout_busy_page); 743 EXPORT_SYMBOL_GPL(dax_layout_busy_page);
744 744
745 static int __dax_invalidate_entry(struct addre 745 static int __dax_invalidate_entry(struct address_space *mapping,
746 pgof 746 pgoff_t index, bool trunc)
747 { 747 {
748 XA_STATE(xas, &mapping->i_pages, index 748 XA_STATE(xas, &mapping->i_pages, index);
749 int ret = 0; 749 int ret = 0;
750 void *entry; 750 void *entry;
751 751
752 xas_lock_irq(&xas); 752 xas_lock_irq(&xas);
753 entry = get_unlocked_entry(&xas, 0); 753 entry = get_unlocked_entry(&xas, 0);
754 if (!entry || WARN_ON_ONCE(!xa_is_valu 754 if (!entry || WARN_ON_ONCE(!xa_is_value(entry)))
755 goto out; 755 goto out;
756 if (!trunc && 756 if (!trunc &&
757 (xas_get_mark(&xas, PAGECACHE_TAG_ 757 (xas_get_mark(&xas, PAGECACHE_TAG_DIRTY) ||
758 xas_get_mark(&xas, PAGECACHE_TAG_ 758 xas_get_mark(&xas, PAGECACHE_TAG_TOWRITE)))
759 goto out; 759 goto out;
760 dax_disassociate_entry(entry, mapping, 760 dax_disassociate_entry(entry, mapping, trunc);
761 xas_store(&xas, NULL); 761 xas_store(&xas, NULL);
762 mapping->nrpages -= 1UL << dax_entry_o 762 mapping->nrpages -= 1UL << dax_entry_order(entry);
763 ret = 1; 763 ret = 1;
764 out: 764 out:
765 put_unlocked_entry(&xas, entry, WAKE_A 765 put_unlocked_entry(&xas, entry, WAKE_ALL);
766 xas_unlock_irq(&xas); 766 xas_unlock_irq(&xas);
767 return ret; 767 return ret;
768 } 768 }
769 769
770 static int __dax_clear_dirty_range(struct addr 770 static int __dax_clear_dirty_range(struct address_space *mapping,
771 pgoff_t start, pgoff_t end) 771 pgoff_t start, pgoff_t end)
772 { 772 {
773 XA_STATE(xas, &mapping->i_pages, start 773 XA_STATE(xas, &mapping->i_pages, start);
774 unsigned int scanned = 0; 774 unsigned int scanned = 0;
775 void *entry; 775 void *entry;
776 776
777 xas_lock_irq(&xas); 777 xas_lock_irq(&xas);
778 xas_for_each(&xas, entry, end) { 778 xas_for_each(&xas, entry, end) {
779 entry = get_unlocked_entry(&xa 779 entry = get_unlocked_entry(&xas, 0);
780 xas_clear_mark(&xas, PAGECACHE 780 xas_clear_mark(&xas, PAGECACHE_TAG_DIRTY);
781 xas_clear_mark(&xas, PAGECACHE 781 xas_clear_mark(&xas, PAGECACHE_TAG_TOWRITE);
782 put_unlocked_entry(&xas, entry 782 put_unlocked_entry(&xas, entry, WAKE_NEXT);
783 783
784 if (++scanned % XA_CHECK_SCHED 784 if (++scanned % XA_CHECK_SCHED)
785 continue; 785 continue;
786 786
787 xas_pause(&xas); 787 xas_pause(&xas);
788 xas_unlock_irq(&xas); 788 xas_unlock_irq(&xas);
789 cond_resched(); 789 cond_resched();
790 xas_lock_irq(&xas); 790 xas_lock_irq(&xas);
791 } 791 }
792 xas_unlock_irq(&xas); 792 xas_unlock_irq(&xas);
793 793
794 return 0; 794 return 0;
795 } 795 }
796 796
797 /* 797 /*
798 * Delete DAX entry at @index from @mapping. 798 * Delete DAX entry at @index from @mapping. Wait for it
799 * to be unlocked before deleting it. 799 * to be unlocked before deleting it.
800 */ 800 */
801 int dax_delete_mapping_entry(struct address_sp 801 int dax_delete_mapping_entry(struct address_space *mapping, pgoff_t index)
802 { 802 {
803 int ret = __dax_invalidate_entry(mappi 803 int ret = __dax_invalidate_entry(mapping, index, true);
804 804
805 /* 805 /*
806 * This gets called from truncate / pu 806 * This gets called from truncate / punch_hole path. As such, the caller
807 * must hold locks protecting against 807 * must hold locks protecting against concurrent modifications of the
808 * page cache (usually fs-private i_mm 808 * page cache (usually fs-private i_mmap_sem for writing). Since the
809 * caller has seen a DAX entry for thi 809 * caller has seen a DAX entry for this index, we better find it
810 * at that index as well... 810 * at that index as well...
811 */ 811 */
812 WARN_ON_ONCE(!ret); 812 WARN_ON_ONCE(!ret);
813 return ret; 813 return ret;
814 } 814 }
815 815
816 /* 816 /*
817 * Invalidate DAX entry if it is clean. 817 * Invalidate DAX entry if it is clean.
818 */ 818 */
819 int dax_invalidate_mapping_entry_sync(struct a 819 int dax_invalidate_mapping_entry_sync(struct address_space *mapping,
820 pgoff_t 820 pgoff_t index)
821 { 821 {
822 return __dax_invalidate_entry(mapping, 822 return __dax_invalidate_entry(mapping, index, false);
823 } 823 }
824 824
825 static pgoff_t dax_iomap_pgoff(const struct io 825 static pgoff_t dax_iomap_pgoff(const struct iomap *iomap, loff_t pos)
826 { 826 {
827 return PHYS_PFN(iomap->addr + (pos & P 827 return PHYS_PFN(iomap->addr + (pos & PAGE_MASK) - iomap->offset);
828 } 828 }
829 829
830 static int copy_cow_page_dax(struct vm_fault * 830 static int copy_cow_page_dax(struct vm_fault *vmf, const struct iomap_iter *iter)
831 { 831 {
832 pgoff_t pgoff = dax_iomap_pgoff(&iter- 832 pgoff_t pgoff = dax_iomap_pgoff(&iter->iomap, iter->pos);
833 void *vto, *kaddr; 833 void *vto, *kaddr;
834 long rc; 834 long rc;
835 int id; 835 int id;
836 836
837 id = dax_read_lock(); 837 id = dax_read_lock();
838 rc = dax_direct_access(iter->iomap.dax 838 rc = dax_direct_access(iter->iomap.dax_dev, pgoff, 1, DAX_ACCESS,
839 &kaddr, NULL); 839 &kaddr, NULL);
840 if (rc < 0) { 840 if (rc < 0) {
841 dax_read_unlock(id); 841 dax_read_unlock(id);
842 return rc; 842 return rc;
843 } 843 }
844 vto = kmap_atomic(vmf->cow_page); 844 vto = kmap_atomic(vmf->cow_page);
845 copy_user_page(vto, kaddr, vmf->addres 845 copy_user_page(vto, kaddr, vmf->address, vmf->cow_page);
846 kunmap_atomic(vto); 846 kunmap_atomic(vto);
847 dax_read_unlock(id); 847 dax_read_unlock(id);
848 return 0; 848 return 0;
849 } 849 }
850 850
851 /* 851 /*
852 * MAP_SYNC on a dax mapping guarantees dirty 852 * MAP_SYNC on a dax mapping guarantees dirty metadata is
853 * flushed on write-faults (non-cow), but not 853 * flushed on write-faults (non-cow), but not read-faults.
854 */ 854 */
855 static bool dax_fault_is_synchronous(const str 855 static bool dax_fault_is_synchronous(const struct iomap_iter *iter,
856 struct vm_area_struct *vma) 856 struct vm_area_struct *vma)
857 { 857 {
858 return (iter->flags & IOMAP_WRITE) && 858 return (iter->flags & IOMAP_WRITE) && (vma->vm_flags & VM_SYNC) &&
859 (iter->iomap.flags & IOMAP_F_D 859 (iter->iomap.flags & IOMAP_F_DIRTY);
860 } 860 }
861 861
862 /* 862 /*
863 * By this point grab_mapping_entry() has ensu 863 * By this point grab_mapping_entry() has ensured that we have a locked entry
864 * of the appropriate size so we don't have to 864 * of the appropriate size so we don't have to worry about downgrading PMDs to
865 * PTEs. If we happen to be trying to insert 865 * PTEs. If we happen to be trying to insert a PTE and there is a PMD
866 * already in the tree, we will skip the inser 866 * already in the tree, we will skip the insertion and just dirty the PMD as
867 * appropriate. 867 * appropriate.
868 */ 868 */
869 static void *dax_insert_entry(struct xa_state 869 static void *dax_insert_entry(struct xa_state *xas, struct vm_fault *vmf,
870 const struct iomap_iter *iter, 870 const struct iomap_iter *iter, void *entry, pfn_t pfn,
871 unsigned long flags) 871 unsigned long flags)
872 { 872 {
873 struct address_space *mapping = vmf->v 873 struct address_space *mapping = vmf->vma->vm_file->f_mapping;
874 void *new_entry = dax_make_entry(pfn, 874 void *new_entry = dax_make_entry(pfn, flags);
875 bool write = iter->flags & IOMAP_WRITE 875 bool write = iter->flags & IOMAP_WRITE;
876 bool dirty = write && !dax_fault_is_sy 876 bool dirty = write && !dax_fault_is_synchronous(iter, vmf->vma);
877 bool shared = iter->iomap.flags & IOMA 877 bool shared = iter->iomap.flags & IOMAP_F_SHARED;
878 878
879 if (dirty) 879 if (dirty)
880 __mark_inode_dirty(mapping->ho 880 __mark_inode_dirty(mapping->host, I_DIRTY_PAGES);
881 881
882 if (shared || (dax_is_zero_entry(entry 882 if (shared || (dax_is_zero_entry(entry) && !(flags & DAX_ZERO_PAGE))) {
883 unsigned long index = xas->xa_ 883 unsigned long index = xas->xa_index;
884 /* we are replacing a zero pag 884 /* we are replacing a zero page with block mapping */
885 if (dax_is_pmd_entry(entry)) 885 if (dax_is_pmd_entry(entry))
886 unmap_mapping_pages(ma 886 unmap_mapping_pages(mapping, index & ~PG_PMD_COLOUR,
887 PG_PMD 887 PG_PMD_NR, false);
888 else /* pte entry */ 888 else /* pte entry */
889 unmap_mapping_pages(ma 889 unmap_mapping_pages(mapping, index, 1, false);
890 } 890 }
891 891
892 xas_reset(xas); 892 xas_reset(xas);
893 xas_lock_irq(xas); 893 xas_lock_irq(xas);
894 if (shared || dax_is_zero_entry(entry) 894 if (shared || dax_is_zero_entry(entry) || dax_is_empty_entry(entry)) {
895 void *old; 895 void *old;
896 896
897 dax_disassociate_entry(entry, 897 dax_disassociate_entry(entry, mapping, false);
898 dax_associate_entry(new_entry, 898 dax_associate_entry(new_entry, mapping, vmf->vma, vmf->address,
899 shared); 899 shared);
900 /* 900 /*
901 * Only swap our new entry int 901 * Only swap our new entry into the page cache if the current
902 * entry is a zero page or an 902 * entry is a zero page or an empty entry. If a normal PTE or
903 * PMD entry is already in the 903 * PMD entry is already in the cache, we leave it alone. This
904 * means that if we are trying 904 * means that if we are trying to insert a PTE and the
905 * existing entry is a PMD, we 905 * existing entry is a PMD, we will just leave the PMD in the
906 * tree and dirty it if necess 906 * tree and dirty it if necessary.
907 */ 907 */
908 old = dax_lock_entry(xas, new_ 908 old = dax_lock_entry(xas, new_entry);
909 WARN_ON_ONCE(old != xa_mk_valu 909 WARN_ON_ONCE(old != xa_mk_value(xa_to_value(entry) |
910 DAX_LO 910 DAX_LOCKED));
911 entry = new_entry; 911 entry = new_entry;
912 } else { 912 } else {
913 xas_load(xas); /* Walk the xa 913 xas_load(xas); /* Walk the xa_state */
914 } 914 }
915 915
916 if (dirty) 916 if (dirty)
917 xas_set_mark(xas, PAGECACHE_TA 917 xas_set_mark(xas, PAGECACHE_TAG_DIRTY);
918 918
919 if (write && shared) 919 if (write && shared)
920 xas_set_mark(xas, PAGECACHE_TA 920 xas_set_mark(xas, PAGECACHE_TAG_TOWRITE);
921 921
922 xas_unlock_irq(xas); 922 xas_unlock_irq(xas);
923 return entry; 923 return entry;
924 } 924 }
925 925
926 static int dax_writeback_one(struct xa_state * 926 static int dax_writeback_one(struct xa_state *xas, struct dax_device *dax_dev,
927 struct address_space *mapping, 927 struct address_space *mapping, void *entry)
928 { 928 {
929 unsigned long pfn, index, count, end; 929 unsigned long pfn, index, count, end;
930 long ret = 0; 930 long ret = 0;
931 struct vm_area_struct *vma; 931 struct vm_area_struct *vma;
932 932
933 /* 933 /*
934 * A page got tagged dirty in DAX mapp 934 * A page got tagged dirty in DAX mapping? Something is seriously
935 * wrong. 935 * wrong.
936 */ 936 */
937 if (WARN_ON(!xa_is_value(entry))) 937 if (WARN_ON(!xa_is_value(entry)))
938 return -EIO; 938 return -EIO;
939 939
940 if (unlikely(dax_is_locked(entry))) { 940 if (unlikely(dax_is_locked(entry))) {
941 void *old_entry = entry; 941 void *old_entry = entry;
942 942
943 entry = get_unlocked_entry(xas 943 entry = get_unlocked_entry(xas, 0);
944 944
945 /* Entry got punched out / rea 945 /* Entry got punched out / reallocated? */
946 if (!entry || WARN_ON_ONCE(!xa 946 if (!entry || WARN_ON_ONCE(!xa_is_value(entry)))
947 goto put_unlocked; 947 goto put_unlocked;
948 /* 948 /*
949 * Entry got reallocated elsew 949 * Entry got reallocated elsewhere? No need to writeback.
950 * We have to compare pfns as 950 * We have to compare pfns as we must not bail out due to
951 * difference in lockbit or en 951 * difference in lockbit or entry type.
952 */ 952 */
953 if (dax_to_pfn(old_entry) != d 953 if (dax_to_pfn(old_entry) != dax_to_pfn(entry))
954 goto put_unlocked; 954 goto put_unlocked;
955 if (WARN_ON_ONCE(dax_is_empty_ 955 if (WARN_ON_ONCE(dax_is_empty_entry(entry) ||
956 dax_is 956 dax_is_zero_entry(entry))) {
957 ret = -EIO; 957 ret = -EIO;
958 goto put_unlocked; 958 goto put_unlocked;
959 } 959 }
960 960
961 /* Another fsync thread may ha 961 /* Another fsync thread may have already done this entry */
962 if (!xas_get_mark(xas, PAGECAC 962 if (!xas_get_mark(xas, PAGECACHE_TAG_TOWRITE))
963 goto put_unlocked; 963 goto put_unlocked;
964 } 964 }
965 965
966 /* Lock the entry to serialize with pa 966 /* Lock the entry to serialize with page faults */
967 dax_lock_entry(xas, entry); 967 dax_lock_entry(xas, entry);
968 968
969 /* 969 /*
970 * We can clear the tag now but we hav 970 * We can clear the tag now but we have to be careful so that concurrent
971 * dax_writeback_one() calls for the s 971 * dax_writeback_one() calls for the same index cannot finish before we
972 * actually flush the caches. This is 972 * actually flush the caches. This is achieved as the calls will look
973 * at the entry only under the i_pages 973 * at the entry only under the i_pages lock and once they do that
974 * they will see the entry locked and 974 * they will see the entry locked and wait for it to unlock.
975 */ 975 */
976 xas_clear_mark(xas, PAGECACHE_TAG_TOWR 976 xas_clear_mark(xas, PAGECACHE_TAG_TOWRITE);
977 xas_unlock_irq(xas); 977 xas_unlock_irq(xas);
978 978
979 /* 979 /*
980 * If dax_writeback_mapping_range() wa 980 * If dax_writeback_mapping_range() was given a wbc->range_start
981 * in the middle of a PMD, the 'index' 981 * in the middle of a PMD, the 'index' we use needs to be
982 * aligned to the start of the PMD. 982 * aligned to the start of the PMD.
983 * This allows us to flush for PMD_SIZ 983 * This allows us to flush for PMD_SIZE and not have to worry about
984 * partial PMD writebacks. 984 * partial PMD writebacks.
985 */ 985 */
986 pfn = dax_to_pfn(entry); 986 pfn = dax_to_pfn(entry);
987 count = 1UL << dax_entry_order(entry); 987 count = 1UL << dax_entry_order(entry);
988 index = xas->xa_index & ~(count - 1); 988 index = xas->xa_index & ~(count - 1);
989 end = index + count - 1; 989 end = index + count - 1;
990 990
991 /* Walk all mappings of a given index 991 /* Walk all mappings of a given index of a file and writeprotect them */
992 i_mmap_lock_read(mapping); 992 i_mmap_lock_read(mapping);
993 vma_interval_tree_foreach(vma, &mappin 993 vma_interval_tree_foreach(vma, &mapping->i_mmap, index, end) {
994 pfn_mkclean_range(pfn, count, 994 pfn_mkclean_range(pfn, count, index, vma);
995 cond_resched(); 995 cond_resched();
996 } 996 }
997 i_mmap_unlock_read(mapping); 997 i_mmap_unlock_read(mapping);
998 998
999 dax_flush(dax_dev, page_address(pfn_to 999 dax_flush(dax_dev, page_address(pfn_to_page(pfn)), count * PAGE_SIZE);
1000 /* 1000 /*
1001 * After we have flushed the cache, w 1001 * After we have flushed the cache, we can clear the dirty tag. There
1002 * cannot be new dirty data in the pf 1002 * cannot be new dirty data in the pfn after the flush has completed as
1003 * the pfn mappings are writeprotecte 1003 * the pfn mappings are writeprotected and fault waits for mapping
1004 * entry lock. 1004 * entry lock.
1005 */ 1005 */
1006 xas_reset(xas); 1006 xas_reset(xas);
1007 xas_lock_irq(xas); 1007 xas_lock_irq(xas);
1008 xas_store(xas, entry); 1008 xas_store(xas, entry);
1009 xas_clear_mark(xas, PAGECACHE_TAG_DIR 1009 xas_clear_mark(xas, PAGECACHE_TAG_DIRTY);
1010 dax_wake_entry(xas, entry, WAKE_NEXT) 1010 dax_wake_entry(xas, entry, WAKE_NEXT);
1011 1011
1012 trace_dax_writeback_one(mapping->host 1012 trace_dax_writeback_one(mapping->host, index, count);
1013 return ret; 1013 return ret;
1014 1014
1015 put_unlocked: 1015 put_unlocked:
1016 put_unlocked_entry(xas, entry, WAKE_N 1016 put_unlocked_entry(xas, entry, WAKE_NEXT);
1017 return ret; 1017 return ret;
1018 } 1018 }
1019 1019
1020 /* 1020 /*
1021 * Flush the mapping to the persistent domain 1021 * Flush the mapping to the persistent domain within the byte range of [start,
1022 * end]. This is required by data integrity o 1022 * end]. This is required by data integrity operations to ensure file data is
1023 * on persistent storage prior to completion 1023 * on persistent storage prior to completion of the operation.
1024 */ 1024 */
1025 int dax_writeback_mapping_range(struct addres 1025 int dax_writeback_mapping_range(struct address_space *mapping,
1026 struct dax_device *dax_dev, s 1026 struct dax_device *dax_dev, struct writeback_control *wbc)
1027 { 1027 {
1028 XA_STATE(xas, &mapping->i_pages, wbc- 1028 XA_STATE(xas, &mapping->i_pages, wbc->range_start >> PAGE_SHIFT);
1029 struct inode *inode = mapping->host; 1029 struct inode *inode = mapping->host;
1030 pgoff_t end_index = wbc->range_end >> 1030 pgoff_t end_index = wbc->range_end >> PAGE_SHIFT;
1031 void *entry; 1031 void *entry;
1032 int ret = 0; 1032 int ret = 0;
1033 unsigned int scanned = 0; 1033 unsigned int scanned = 0;
1034 1034
1035 if (WARN_ON_ONCE(inode->i_blkbits != 1035 if (WARN_ON_ONCE(inode->i_blkbits != PAGE_SHIFT))
1036 return -EIO; 1036 return -EIO;
1037 1037
1038 if (mapping_empty(mapping) || wbc->sy 1038 if (mapping_empty(mapping) || wbc->sync_mode != WB_SYNC_ALL)
1039 return 0; 1039 return 0;
1040 1040
1041 trace_dax_writeback_range(inode, xas. 1041 trace_dax_writeback_range(inode, xas.xa_index, end_index);
1042 1042
1043 tag_pages_for_writeback(mapping, xas. 1043 tag_pages_for_writeback(mapping, xas.xa_index, end_index);
1044 1044
1045 xas_lock_irq(&xas); 1045 xas_lock_irq(&xas);
1046 xas_for_each_marked(&xas, entry, end_ 1046 xas_for_each_marked(&xas, entry, end_index, PAGECACHE_TAG_TOWRITE) {
1047 ret = dax_writeback_one(&xas, 1047 ret = dax_writeback_one(&xas, dax_dev, mapping, entry);
1048 if (ret < 0) { 1048 if (ret < 0) {
1049 mapping_set_error(map 1049 mapping_set_error(mapping, ret);
1050 break; 1050 break;
1051 } 1051 }
1052 if (++scanned % XA_CHECK_SCHE 1052 if (++scanned % XA_CHECK_SCHED)
1053 continue; 1053 continue;
1054 1054
1055 xas_pause(&xas); 1055 xas_pause(&xas);
1056 xas_unlock_irq(&xas); 1056 xas_unlock_irq(&xas);
1057 cond_resched(); 1057 cond_resched();
1058 xas_lock_irq(&xas); 1058 xas_lock_irq(&xas);
1059 } 1059 }
1060 xas_unlock_irq(&xas); 1060 xas_unlock_irq(&xas);
1061 trace_dax_writeback_range_done(inode, 1061 trace_dax_writeback_range_done(inode, xas.xa_index, end_index);
1062 return ret; 1062 return ret;
1063 } 1063 }
1064 EXPORT_SYMBOL_GPL(dax_writeback_mapping_range 1064 EXPORT_SYMBOL_GPL(dax_writeback_mapping_range);
1065 1065
1066 static int dax_iomap_direct_access(const stru 1066 static int dax_iomap_direct_access(const struct iomap *iomap, loff_t pos,
1067 size_t size, void **kaddr, pf 1067 size_t size, void **kaddr, pfn_t *pfnp)
1068 { 1068 {
1069 pgoff_t pgoff = dax_iomap_pgoff(iomap 1069 pgoff_t pgoff = dax_iomap_pgoff(iomap, pos);
1070 int id, rc = 0; 1070 int id, rc = 0;
1071 long length; 1071 long length;
1072 1072
1073 id = dax_read_lock(); 1073 id = dax_read_lock();
1074 length = dax_direct_access(iomap->dax 1074 length = dax_direct_access(iomap->dax_dev, pgoff, PHYS_PFN(size),
1075 DAX_ACCESS 1075 DAX_ACCESS, kaddr, pfnp);
1076 if (length < 0) { 1076 if (length < 0) {
1077 rc = length; 1077 rc = length;
1078 goto out; 1078 goto out;
1079 } 1079 }
1080 if (!pfnp) 1080 if (!pfnp)
1081 goto out_check_addr; 1081 goto out_check_addr;
1082 rc = -EINVAL; 1082 rc = -EINVAL;
1083 if (PFN_PHYS(length) < size) 1083 if (PFN_PHYS(length) < size)
1084 goto out; 1084 goto out;
1085 if (pfn_t_to_pfn(*pfnp) & (PHYS_PFN(s 1085 if (pfn_t_to_pfn(*pfnp) & (PHYS_PFN(size)-1))
1086 goto out; 1086 goto out;
1087 /* For larger pages we need devmap */ 1087 /* For larger pages we need devmap */
1088 if (length > 1 && !pfn_t_devmap(*pfnp 1088 if (length > 1 && !pfn_t_devmap(*pfnp))
1089 goto out; 1089 goto out;
1090 rc = 0; 1090 rc = 0;
1091 1091
1092 out_check_addr: 1092 out_check_addr:
1093 if (!kaddr) 1093 if (!kaddr)
1094 goto out; 1094 goto out;
1095 if (!*kaddr) 1095 if (!*kaddr)
1096 rc = -EFAULT; 1096 rc = -EFAULT;
1097 out: 1097 out:
1098 dax_read_unlock(id); 1098 dax_read_unlock(id);
1099 return rc; 1099 return rc;
1100 } 1100 }
1101 1101
1102 /** 1102 /**
1103 * dax_iomap_copy_around - Prepare for an una 1103 * dax_iomap_copy_around - Prepare for an unaligned write to a shared/cow page
1104 * by copying the data before and after the r 1104 * by copying the data before and after the range to be written.
1105 * @pos: address to do copy from. 1105 * @pos: address to do copy from.
1106 * @length: size of copy operation. 1106 * @length: size of copy operation.
1107 * @align_size: aligned w.r.t align_size (eit 1107 * @align_size: aligned w.r.t align_size (either PMD_SIZE or PAGE_SIZE)
1108 * @srcmap: iomap srcmap 1108 * @srcmap: iomap srcmap
1109 * @daddr: destination address to copy t 1109 * @daddr: destination address to copy to.
1110 * 1110 *
1111 * This can be called from two places. Either 1111 * This can be called from two places. Either during DAX write fault (page
1112 * aligned), to copy the length size data to 1112 * aligned), to copy the length size data to daddr. Or, while doing normal DAX
1113 * write operation, dax_iomap_iter() might ca 1113 * write operation, dax_iomap_iter() might call this to do the copy of either
1114 * start or end unaligned address. In the lat 1114 * start or end unaligned address. In the latter case the rest of the copy of
1115 * aligned ranges is taken care by dax_iomap_ 1115 * aligned ranges is taken care by dax_iomap_iter() itself.
1116 * If the srcmap contains invalid data, such 1116 * If the srcmap contains invalid data, such as HOLE and UNWRITTEN, zero the
1117 * area to make sure no old data remains. 1117 * area to make sure no old data remains.
1118 */ 1118 */
1119 static int dax_iomap_copy_around(loff_t pos, 1119 static int dax_iomap_copy_around(loff_t pos, uint64_t length, size_t align_size,
1120 const struct iomap *srcmap, v 1120 const struct iomap *srcmap, void *daddr)
1121 { 1121 {
1122 loff_t head_off = pos & (align_size - 1122 loff_t head_off = pos & (align_size - 1);
1123 size_t size = ALIGN(head_off + length 1123 size_t size = ALIGN(head_off + length, align_size);
1124 loff_t end = pos + length; 1124 loff_t end = pos + length;
1125 loff_t pg_end = round_up(end, align_s 1125 loff_t pg_end = round_up(end, align_size);
1126 /* copy_all is usually in page fault 1126 /* copy_all is usually in page fault case */
1127 bool copy_all = head_off == 0 && end 1127 bool copy_all = head_off == 0 && end == pg_end;
1128 /* zero the edges if srcmap is a HOLE 1128 /* zero the edges if srcmap is a HOLE or IOMAP_UNWRITTEN */
1129 bool zero_edge = srcmap->flags & IOMA 1129 bool zero_edge = srcmap->flags & IOMAP_F_SHARED ||
1130 srcmap->type == IOMA 1130 srcmap->type == IOMAP_UNWRITTEN;
1131 void *saddr = NULL; 1131 void *saddr = NULL;
1132 int ret = 0; 1132 int ret = 0;
1133 1133
1134 if (!zero_edge) { 1134 if (!zero_edge) {
1135 ret = dax_iomap_direct_access 1135 ret = dax_iomap_direct_access(srcmap, pos, size, &saddr, NULL);
1136 if (ret) 1136 if (ret)
1137 return dax_mem2blk_er 1137 return dax_mem2blk_err(ret);
1138 } 1138 }
1139 1139
1140 if (copy_all) { 1140 if (copy_all) {
1141 if (zero_edge) 1141 if (zero_edge)
1142 memset(daddr, 0, size 1142 memset(daddr, 0, size);
1143 else 1143 else
1144 ret = copy_mc_to_kern 1144 ret = copy_mc_to_kernel(daddr, saddr, length);
1145 goto out; 1145 goto out;
1146 } 1146 }
1147 1147
1148 /* Copy the head part of the range */ 1148 /* Copy the head part of the range */
1149 if (head_off) { 1149 if (head_off) {
1150 if (zero_edge) 1150 if (zero_edge)
1151 memset(daddr, 0, head 1151 memset(daddr, 0, head_off);
1152 else { 1152 else {
1153 ret = copy_mc_to_kern 1153 ret = copy_mc_to_kernel(daddr, saddr, head_off);
1154 if (ret) 1154 if (ret)
1155 return -EIO; 1155 return -EIO;
1156 } 1156 }
1157 } 1157 }
1158 1158
1159 /* Copy the tail part of the range */ 1159 /* Copy the tail part of the range */
1160 if (end < pg_end) { 1160 if (end < pg_end) {
1161 loff_t tail_off = head_off + 1161 loff_t tail_off = head_off + length;
1162 loff_t tail_len = pg_end - en 1162 loff_t tail_len = pg_end - end;
1163 1163
1164 if (zero_edge) 1164 if (zero_edge)
1165 memset(daddr + tail_o 1165 memset(daddr + tail_off, 0, tail_len);
1166 else { 1166 else {
1167 ret = copy_mc_to_kern 1167 ret = copy_mc_to_kernel(daddr + tail_off,
1168 1168 saddr + tail_off, tail_len);
1169 if (ret) 1169 if (ret)
1170 return -EIO; 1170 return -EIO;
1171 } 1171 }
1172 } 1172 }
1173 out: 1173 out:
1174 if (zero_edge) 1174 if (zero_edge)
1175 dax_flush(srcmap->dax_dev, da 1175 dax_flush(srcmap->dax_dev, daddr, size);
1176 return ret ? -EIO : 0; 1176 return ret ? -EIO : 0;
1177 } 1177 }
1178 1178
1179 /* 1179 /*
1180 * The user has performed a load from a hole 1180 * The user has performed a load from a hole in the file. Allocating a new
1181 * page in the file would cause excessive sto 1181 * page in the file would cause excessive storage usage for workloads with
1182 * sparse files. Instead we insert a read-on 1182 * sparse files. Instead we insert a read-only mapping of the 4k zero page.
1183 * If this page is ever written to we will re 1183 * If this page is ever written to we will re-fault and change the mapping to
1184 * point to real DAX storage instead. 1184 * point to real DAX storage instead.
1185 */ 1185 */
1186 static vm_fault_t dax_load_hole(struct xa_sta 1186 static vm_fault_t dax_load_hole(struct xa_state *xas, struct vm_fault *vmf,
1187 const struct iomap_iter *iter 1187 const struct iomap_iter *iter, void **entry)
1188 { 1188 {
1189 struct inode *inode = iter->inode; 1189 struct inode *inode = iter->inode;
1190 unsigned long vaddr = vmf->address; 1190 unsigned long vaddr = vmf->address;
1191 pfn_t pfn = pfn_to_pfn_t(my_zero_pfn( 1191 pfn_t pfn = pfn_to_pfn_t(my_zero_pfn(vaddr));
1192 vm_fault_t ret; 1192 vm_fault_t ret;
1193 1193
1194 *entry = dax_insert_entry(xas, vmf, i 1194 *entry = dax_insert_entry(xas, vmf, iter, *entry, pfn, DAX_ZERO_PAGE);
1195 1195
1196 ret = vmf_insert_mixed(vmf->vma, vadd 1196 ret = vmf_insert_mixed(vmf->vma, vaddr, pfn);
1197 trace_dax_load_hole(inode, vmf, ret); 1197 trace_dax_load_hole(inode, vmf, ret);
1198 return ret; 1198 return ret;
1199 } 1199 }
1200 1200
1201 #ifdef CONFIG_FS_DAX_PMD 1201 #ifdef CONFIG_FS_DAX_PMD
1202 static vm_fault_t dax_pmd_load_hole(struct xa 1202 static vm_fault_t dax_pmd_load_hole(struct xa_state *xas, struct vm_fault *vmf,
1203 const struct iomap_iter *iter 1203 const struct iomap_iter *iter, void **entry)
1204 { 1204 {
1205 struct address_space *mapping = vmf-> 1205 struct address_space *mapping = vmf->vma->vm_file->f_mapping;
1206 unsigned long pmd_addr = vmf->address 1206 unsigned long pmd_addr = vmf->address & PMD_MASK;
1207 struct vm_area_struct *vma = vmf->vma 1207 struct vm_area_struct *vma = vmf->vma;
1208 struct inode *inode = mapping->host; 1208 struct inode *inode = mapping->host;
1209 pgtable_t pgtable = NULL; 1209 pgtable_t pgtable = NULL;
1210 struct folio *zero_folio; 1210 struct folio *zero_folio;
1211 spinlock_t *ptl; 1211 spinlock_t *ptl;
1212 pmd_t pmd_entry; 1212 pmd_t pmd_entry;
1213 pfn_t pfn; 1213 pfn_t pfn;
1214 1214
1215 zero_folio = mm_get_huge_zero_folio(v 1215 zero_folio = mm_get_huge_zero_folio(vmf->vma->vm_mm);
1216 1216
1217 if (unlikely(!zero_folio)) 1217 if (unlikely(!zero_folio))
1218 goto fallback; 1218 goto fallback;
1219 1219
1220 pfn = page_to_pfn_t(&zero_folio->page 1220 pfn = page_to_pfn_t(&zero_folio->page);
1221 *entry = dax_insert_entry(xas, vmf, i 1221 *entry = dax_insert_entry(xas, vmf, iter, *entry, pfn,
1222 DAX_PMD | D 1222 DAX_PMD | DAX_ZERO_PAGE);
1223 1223
1224 if (arch_needs_pgtable_deposit()) { 1224 if (arch_needs_pgtable_deposit()) {
1225 pgtable = pte_alloc_one(vma-> 1225 pgtable = pte_alloc_one(vma->vm_mm);
1226 if (!pgtable) 1226 if (!pgtable)
1227 return VM_FAULT_OOM; 1227 return VM_FAULT_OOM;
1228 } 1228 }
1229 1229
1230 ptl = pmd_lock(vmf->vma->vm_mm, vmf-> 1230 ptl = pmd_lock(vmf->vma->vm_mm, vmf->pmd);
1231 if (!pmd_none(*(vmf->pmd))) { 1231 if (!pmd_none(*(vmf->pmd))) {
1232 spin_unlock(ptl); 1232 spin_unlock(ptl);
1233 goto fallback; 1233 goto fallback;
1234 } 1234 }
1235 1235
1236 if (pgtable) { 1236 if (pgtable) {
1237 pgtable_trans_huge_deposit(vm 1237 pgtable_trans_huge_deposit(vma->vm_mm, vmf->pmd, pgtable);
1238 mm_inc_nr_ptes(vma->vm_mm); 1238 mm_inc_nr_ptes(vma->vm_mm);
1239 } 1239 }
1240 pmd_entry = mk_pmd(&zero_folio->page, 1240 pmd_entry = mk_pmd(&zero_folio->page, vmf->vma->vm_page_prot);
1241 pmd_entry = pmd_mkhuge(pmd_entry); 1241 pmd_entry = pmd_mkhuge(pmd_entry);
1242 set_pmd_at(vmf->vma->vm_mm, pmd_addr, 1242 set_pmd_at(vmf->vma->vm_mm, pmd_addr, vmf->pmd, pmd_entry);
1243 spin_unlock(ptl); 1243 spin_unlock(ptl);
1244 trace_dax_pmd_load_hole(inode, vmf, z 1244 trace_dax_pmd_load_hole(inode, vmf, zero_folio, *entry);
1245 return VM_FAULT_NOPAGE; 1245 return VM_FAULT_NOPAGE;
1246 1246
1247 fallback: 1247 fallback:
1248 if (pgtable) 1248 if (pgtable)
1249 pte_free(vma->vm_mm, pgtable) 1249 pte_free(vma->vm_mm, pgtable);
1250 trace_dax_pmd_load_hole_fallback(inod 1250 trace_dax_pmd_load_hole_fallback(inode, vmf, zero_folio, *entry);
1251 return VM_FAULT_FALLBACK; 1251 return VM_FAULT_FALLBACK;
1252 } 1252 }
1253 #else 1253 #else
1254 static vm_fault_t dax_pmd_load_hole(struct xa 1254 static vm_fault_t dax_pmd_load_hole(struct xa_state *xas, struct vm_fault *vmf,
1255 const struct iomap_iter *iter 1255 const struct iomap_iter *iter, void **entry)
1256 { 1256 {
1257 return VM_FAULT_FALLBACK; 1257 return VM_FAULT_FALLBACK;
1258 } 1258 }
1259 #endif /* CONFIG_FS_DAX_PMD */ 1259 #endif /* CONFIG_FS_DAX_PMD */
1260 1260
1261 static s64 dax_unshare_iter(struct iomap_iter 1261 static s64 dax_unshare_iter(struct iomap_iter *iter)
1262 { 1262 {
1263 struct iomap *iomap = &iter->iomap; 1263 struct iomap *iomap = &iter->iomap;
1264 const struct iomap *srcmap = iomap_it 1264 const struct iomap *srcmap = iomap_iter_srcmap(iter);
1265 loff_t copy_pos = iter->pos; 1265 loff_t copy_pos = iter->pos;
1266 u64 copy_len = iomap_length(iter); 1266 u64 copy_len = iomap_length(iter);
1267 u32 mod; 1267 u32 mod;
1268 int id = 0; 1268 int id = 0;
1269 s64 ret = 0; 1269 s64 ret = 0;
1270 void *daddr = NULL, *saddr = NULL; 1270 void *daddr = NULL, *saddr = NULL;
1271 1271
1272 if (!iomap_want_unshare_iter(iter)) 1272 if (!iomap_want_unshare_iter(iter))
1273 return iomap_length(iter); 1273 return iomap_length(iter);
1274 1274
1275 /* 1275 /*
1276 * Extend the file range to be aligne 1276 * Extend the file range to be aligned to fsblock/pagesize, because
1277 * we need to copy entire blocks, not 1277 * we need to copy entire blocks, not just the byte range specified.
1278 * Invalidate the mapping because we' 1278 * Invalidate the mapping because we're about to CoW.
1279 */ 1279 */
1280 mod = offset_in_page(copy_pos); 1280 mod = offset_in_page(copy_pos);
1281 if (mod) { 1281 if (mod) {
1282 copy_len += mod; 1282 copy_len += mod;
1283 copy_pos -= mod; 1283 copy_pos -= mod;
1284 } 1284 }
1285 1285
1286 mod = offset_in_page(copy_pos + copy_ 1286 mod = offset_in_page(copy_pos + copy_len);
1287 if (mod) 1287 if (mod)
1288 copy_len += PAGE_SIZE - mod; 1288 copy_len += PAGE_SIZE - mod;
1289 1289
1290 invalidate_inode_pages2_range(iter->i 1290 invalidate_inode_pages2_range(iter->inode->i_mapping,
1291 copy_po 1291 copy_pos >> PAGE_SHIFT,
1292 (copy_p 1292 (copy_pos + copy_len - 1) >> PAGE_SHIFT);
1293 1293
1294 id = dax_read_lock(); 1294 id = dax_read_lock();
1295 ret = dax_iomap_direct_access(iomap, 1295 ret = dax_iomap_direct_access(iomap, copy_pos, copy_len, &daddr, NULL);
1296 if (ret < 0) 1296 if (ret < 0)
1297 goto out_unlock; 1297 goto out_unlock;
1298 1298
1299 ret = dax_iomap_direct_access(srcmap, 1299 ret = dax_iomap_direct_access(srcmap, copy_pos, copy_len, &saddr, NULL);
1300 if (ret < 0) 1300 if (ret < 0)
1301 goto out_unlock; 1301 goto out_unlock;
1302 1302
1303 if (copy_mc_to_kernel(daddr, saddr, c 1303 if (copy_mc_to_kernel(daddr, saddr, copy_len) == 0)
1304 ret = iomap_length(iter); 1304 ret = iomap_length(iter);
1305 else 1305 else
1306 ret = -EIO; 1306 ret = -EIO;
1307 1307
1308 out_unlock: 1308 out_unlock:
1309 dax_read_unlock(id); 1309 dax_read_unlock(id);
1310 return dax_mem2blk_err(ret); 1310 return dax_mem2blk_err(ret);
1311 } 1311 }
1312 1312
1313 int dax_file_unshare(struct inode *inode, lof 1313 int dax_file_unshare(struct inode *inode, loff_t pos, loff_t len,
1314 const struct iomap_ops *ops) 1314 const struct iomap_ops *ops)
1315 { 1315 {
1316 struct iomap_iter iter = { 1316 struct iomap_iter iter = {
1317 .inode = inode, 1317 .inode = inode,
1318 .pos = pos, 1318 .pos = pos,
1319 .flags = IOMAP_WRITE 1319 .flags = IOMAP_WRITE | IOMAP_UNSHARE | IOMAP_DAX,
1320 }; 1320 };
1321 loff_t size = i_size_read(inode); 1321 loff_t size = i_size_read(inode);
1322 int ret; 1322 int ret;
1323 1323
1324 if (pos < 0 || pos >= size) 1324 if (pos < 0 || pos >= size)
1325 return 0; 1325 return 0;
1326 1326
1327 iter.len = min(len, size - pos); 1327 iter.len = min(len, size - pos);
1328 while ((ret = iomap_iter(&iter, ops)) 1328 while ((ret = iomap_iter(&iter, ops)) > 0)
1329 iter.processed = dax_unshare_ 1329 iter.processed = dax_unshare_iter(&iter);
1330 return ret; 1330 return ret;
1331 } 1331 }
1332 EXPORT_SYMBOL_GPL(dax_file_unshare); 1332 EXPORT_SYMBOL_GPL(dax_file_unshare);
1333 1333
1334 static int dax_memzero(struct iomap_iter *ite 1334 static int dax_memzero(struct iomap_iter *iter, loff_t pos, size_t size)
1335 { 1335 {
1336 const struct iomap *iomap = &iter->io 1336 const struct iomap *iomap = &iter->iomap;
1337 const struct iomap *srcmap = iomap_it 1337 const struct iomap *srcmap = iomap_iter_srcmap(iter);
1338 unsigned offset = offset_in_page(pos) 1338 unsigned offset = offset_in_page(pos);
1339 pgoff_t pgoff = dax_iomap_pgoff(iomap 1339 pgoff_t pgoff = dax_iomap_pgoff(iomap, pos);
1340 void *kaddr; 1340 void *kaddr;
1341 long ret; 1341 long ret;
1342 1342
1343 ret = dax_direct_access(iomap->dax_de 1343 ret = dax_direct_access(iomap->dax_dev, pgoff, 1, DAX_ACCESS, &kaddr,
1344 NULL); 1344 NULL);
1345 if (ret < 0) 1345 if (ret < 0)
1346 return dax_mem2blk_err(ret); 1346 return dax_mem2blk_err(ret);
1347 1347
1348 memset(kaddr + offset, 0, size); 1348 memset(kaddr + offset, 0, size);
1349 if (iomap->flags & IOMAP_F_SHARED) 1349 if (iomap->flags & IOMAP_F_SHARED)
1350 ret = dax_iomap_copy_around(p 1350 ret = dax_iomap_copy_around(pos, size, PAGE_SIZE, srcmap,
1351 k 1351 kaddr);
1352 else 1352 else
1353 dax_flush(iomap->dax_dev, kad 1353 dax_flush(iomap->dax_dev, kaddr + offset, size);
1354 return ret; 1354 return ret;
1355 } 1355 }
1356 1356
1357 static s64 dax_zero_iter(struct iomap_iter *i 1357 static s64 dax_zero_iter(struct iomap_iter *iter, bool *did_zero)
1358 { 1358 {
1359 const struct iomap *iomap = &iter->io 1359 const struct iomap *iomap = &iter->iomap;
1360 const struct iomap *srcmap = iomap_it 1360 const struct iomap *srcmap = iomap_iter_srcmap(iter);
1361 loff_t pos = iter->pos; 1361 loff_t pos = iter->pos;
1362 u64 length = iomap_length(iter); 1362 u64 length = iomap_length(iter);
1363 s64 written = 0; 1363 s64 written = 0;
1364 1364
1365 /* already zeroed? we're done. */ 1365 /* already zeroed? we're done. */
1366 if (srcmap->type == IOMAP_HOLE || src 1366 if (srcmap->type == IOMAP_HOLE || srcmap->type == IOMAP_UNWRITTEN)
1367 return length; 1367 return length;
1368 1368
1369 /* 1369 /*
1370 * invalidate the pages whose sharing 1370 * invalidate the pages whose sharing state is to be changed
1371 * because of CoW. 1371 * because of CoW.
1372 */ 1372 */
1373 if (iomap->flags & IOMAP_F_SHARED) 1373 if (iomap->flags & IOMAP_F_SHARED)
1374 invalidate_inode_pages2_range 1374 invalidate_inode_pages2_range(iter->inode->i_mapping,
1375 1375 pos >> PAGE_SHIFT,
1376 1376 (pos + length - 1) >> PAGE_SHIFT);
1377 1377
1378 do { 1378 do {
1379 unsigned offset = offset_in_p 1379 unsigned offset = offset_in_page(pos);
1380 unsigned size = min_t(u64, PA 1380 unsigned size = min_t(u64, PAGE_SIZE - offset, length);
1381 pgoff_t pgoff = dax_iomap_pgo 1381 pgoff_t pgoff = dax_iomap_pgoff(iomap, pos);
1382 long rc; 1382 long rc;
1383 int id; 1383 int id;
1384 1384
1385 id = dax_read_lock(); 1385 id = dax_read_lock();
1386 if (IS_ALIGNED(pos, PAGE_SIZE 1386 if (IS_ALIGNED(pos, PAGE_SIZE) && size == PAGE_SIZE)
1387 rc = dax_zero_page_ra 1387 rc = dax_zero_page_range(iomap->dax_dev, pgoff, 1);
1388 else 1388 else
1389 rc = dax_memzero(iter 1389 rc = dax_memzero(iter, pos, size);
1390 dax_read_unlock(id); 1390 dax_read_unlock(id);
1391 1391
1392 if (rc < 0) 1392 if (rc < 0)
1393 return rc; 1393 return rc;
1394 pos += size; 1394 pos += size;
1395 length -= size; 1395 length -= size;
1396 written += size; 1396 written += size;
1397 } while (length > 0); 1397 } while (length > 0);
1398 1398
1399 if (did_zero) 1399 if (did_zero)
1400 *did_zero = true; 1400 *did_zero = true;
1401 return written; 1401 return written;
1402 } 1402 }
1403 1403
1404 int dax_zero_range(struct inode *inode, loff_ 1404 int dax_zero_range(struct inode *inode, loff_t pos, loff_t len, bool *did_zero,
1405 const struct iomap_ops *ops) 1405 const struct iomap_ops *ops)
1406 { 1406 {
1407 struct iomap_iter iter = { 1407 struct iomap_iter iter = {
1408 .inode = inode, 1408 .inode = inode,
1409 .pos = pos, 1409 .pos = pos,
1410 .len = len, 1410 .len = len,
1411 .flags = IOMAP_DAX | 1411 .flags = IOMAP_DAX | IOMAP_ZERO,
1412 }; 1412 };
1413 int ret; 1413 int ret;
1414 1414
1415 while ((ret = iomap_iter(&iter, ops)) 1415 while ((ret = iomap_iter(&iter, ops)) > 0)
1416 iter.processed = dax_zero_ite 1416 iter.processed = dax_zero_iter(&iter, did_zero);
1417 return ret; 1417 return ret;
1418 } 1418 }
1419 EXPORT_SYMBOL_GPL(dax_zero_range); 1419 EXPORT_SYMBOL_GPL(dax_zero_range);
1420 1420
1421 int dax_truncate_page(struct inode *inode, lo 1421 int dax_truncate_page(struct inode *inode, loff_t pos, bool *did_zero,
1422 const struct iomap_ops *ops) 1422 const struct iomap_ops *ops)
1423 { 1423 {
1424 unsigned int blocksize = i_blocksize( 1424 unsigned int blocksize = i_blocksize(inode);
1425 unsigned int off = pos & (blocksize - 1425 unsigned int off = pos & (blocksize - 1);
1426 1426
1427 /* Block boundary? Nothing to do */ 1427 /* Block boundary? Nothing to do */
1428 if (!off) 1428 if (!off)
1429 return 0; 1429 return 0;
1430 return dax_zero_range(inode, pos, blo 1430 return dax_zero_range(inode, pos, blocksize - off, did_zero, ops);
1431 } 1431 }
1432 EXPORT_SYMBOL_GPL(dax_truncate_page); 1432 EXPORT_SYMBOL_GPL(dax_truncate_page);
1433 1433
1434 static loff_t dax_iomap_iter(const struct iom 1434 static loff_t dax_iomap_iter(const struct iomap_iter *iomi,
1435 struct iov_iter *iter) 1435 struct iov_iter *iter)
1436 { 1436 {
1437 const struct iomap *iomap = &iomi->io 1437 const struct iomap *iomap = &iomi->iomap;
1438 const struct iomap *srcmap = iomap_it 1438 const struct iomap *srcmap = iomap_iter_srcmap(iomi);
1439 loff_t length = iomap_length(iomi); 1439 loff_t length = iomap_length(iomi);
1440 loff_t pos = iomi->pos; 1440 loff_t pos = iomi->pos;
1441 struct dax_device *dax_dev = iomap->d 1441 struct dax_device *dax_dev = iomap->dax_dev;
1442 loff_t end = pos + length, done = 0; 1442 loff_t end = pos + length, done = 0;
1443 bool write = iov_iter_rw(iter) == WRI 1443 bool write = iov_iter_rw(iter) == WRITE;
1444 bool cow = write && iomap->flags & IO 1444 bool cow = write && iomap->flags & IOMAP_F_SHARED;
1445 ssize_t ret = 0; 1445 ssize_t ret = 0;
1446 size_t xfer; 1446 size_t xfer;
1447 int id; 1447 int id;
1448 1448
1449 if (!write) { 1449 if (!write) {
1450 end = min(end, i_size_read(io 1450 end = min(end, i_size_read(iomi->inode));
1451 if (pos >= end) 1451 if (pos >= end)
1452 return 0; 1452 return 0;
1453 1453
1454 if (iomap->type == IOMAP_HOLE 1454 if (iomap->type == IOMAP_HOLE || iomap->type == IOMAP_UNWRITTEN)
1455 return iov_iter_zero( 1455 return iov_iter_zero(min(length, end - pos), iter);
1456 } 1456 }
1457 1457
1458 /* 1458 /*
1459 * In DAX mode, enforce either pure o 1459 * In DAX mode, enforce either pure overwrites of written extents, or
1460 * writes to unwritten extents as par 1460 * writes to unwritten extents as part of a copy-on-write operation.
1461 */ 1461 */
1462 if (WARN_ON_ONCE(iomap->type != IOMAP 1462 if (WARN_ON_ONCE(iomap->type != IOMAP_MAPPED &&
1463 !(iomap->flags & IOMA 1463 !(iomap->flags & IOMAP_F_SHARED)))
1464 return -EIO; 1464 return -EIO;
1465 1465
1466 /* 1466 /*
1467 * Write can allocate block for an ar 1467 * Write can allocate block for an area which has a hole page mapped
1468 * into page tables. We have to tear 1468 * into page tables. We have to tear down these mappings so that data
1469 * written by write(2) is visible in 1469 * written by write(2) is visible in mmap.
1470 */ 1470 */
1471 if (iomap->flags & IOMAP_F_NEW || cow 1471 if (iomap->flags & IOMAP_F_NEW || cow) {
1472 /* 1472 /*
1473 * Filesystem allows CoW on n 1473 * Filesystem allows CoW on non-shared extents. The src extents
1474 * may have been mmapped with 1474 * may have been mmapped with dirty mark before. To be able to
1475 * invalidate its dax entries 1475 * invalidate its dax entries, we need to clear the dirty mark
1476 * in advance. 1476 * in advance.
1477 */ 1477 */
1478 if (cow) 1478 if (cow)
1479 __dax_clear_dirty_ran 1479 __dax_clear_dirty_range(iomi->inode->i_mapping,
1480 1480 pos >> PAGE_SHIFT,
1481 1481 (end - 1) >> PAGE_SHIFT);
1482 invalidate_inode_pages2_range 1482 invalidate_inode_pages2_range(iomi->inode->i_mapping,
1483 1483 pos >> PAGE_SHIFT,
1484 1484 (end - 1) >> PAGE_SHIFT);
1485 } 1485 }
1486 1486
1487 id = dax_read_lock(); 1487 id = dax_read_lock();
1488 while (pos < end) { 1488 while (pos < end) {
1489 unsigned offset = pos & (PAGE 1489 unsigned offset = pos & (PAGE_SIZE - 1);
1490 const size_t size = ALIGN(len 1490 const size_t size = ALIGN(length + offset, PAGE_SIZE);
1491 pgoff_t pgoff = dax_iomap_pgo 1491 pgoff_t pgoff = dax_iomap_pgoff(iomap, pos);
1492 ssize_t map_len; 1492 ssize_t map_len;
1493 bool recovery = false; 1493 bool recovery = false;
1494 void *kaddr; 1494 void *kaddr;
1495 1495
1496 if (fatal_signal_pending(curr 1496 if (fatal_signal_pending(current)) {
1497 ret = -EINTR; 1497 ret = -EINTR;
1498 break; 1498 break;
1499 } 1499 }
1500 1500
1501 map_len = dax_direct_access(d 1501 map_len = dax_direct_access(dax_dev, pgoff, PHYS_PFN(size),
1502 DAX_ACCESS, & 1502 DAX_ACCESS, &kaddr, NULL);
1503 if (map_len == -EHWPOISON && 1503 if (map_len == -EHWPOISON && iov_iter_rw(iter) == WRITE) {
1504 map_len = dax_direct_ 1504 map_len = dax_direct_access(dax_dev, pgoff,
1505 PHYS_ 1505 PHYS_PFN(size), DAX_RECOVERY_WRITE,
1506 &kadd 1506 &kaddr, NULL);
1507 if (map_len > 0) 1507 if (map_len > 0)
1508 recovery = tr 1508 recovery = true;
1509 } 1509 }
1510 if (map_len < 0) { 1510 if (map_len < 0) {
1511 ret = dax_mem2blk_err 1511 ret = dax_mem2blk_err(map_len);
1512 break; 1512 break;
1513 } 1513 }
1514 1514
1515 if (cow) { 1515 if (cow) {
1516 ret = dax_iomap_copy_ 1516 ret = dax_iomap_copy_around(pos, length, PAGE_SIZE,
1517 1517 srcmap, kaddr);
1518 if (ret) 1518 if (ret)
1519 break; 1519 break;
1520 } 1520 }
1521 1521
1522 map_len = PFN_PHYS(map_len); 1522 map_len = PFN_PHYS(map_len);
1523 kaddr += offset; 1523 kaddr += offset;
1524 map_len -= offset; 1524 map_len -= offset;
1525 if (map_len > end - pos) 1525 if (map_len > end - pos)
1526 map_len = end - pos; 1526 map_len = end - pos;
1527 1527
1528 if (recovery) 1528 if (recovery)
1529 xfer = dax_recovery_w 1529 xfer = dax_recovery_write(dax_dev, pgoff, kaddr,
1530 map_l 1530 map_len, iter);
1531 else if (write) 1531 else if (write)
1532 xfer = dax_copy_from_ 1532 xfer = dax_copy_from_iter(dax_dev, pgoff, kaddr,
1533 map_l 1533 map_len, iter);
1534 else 1534 else
1535 xfer = dax_copy_to_it 1535 xfer = dax_copy_to_iter(dax_dev, pgoff, kaddr,
1536 map_l 1536 map_len, iter);
1537 1537
1538 pos += xfer; 1538 pos += xfer;
1539 length -= xfer; 1539 length -= xfer;
1540 done += xfer; 1540 done += xfer;
1541 1541
1542 if (xfer == 0) 1542 if (xfer == 0)
1543 ret = -EFAULT; 1543 ret = -EFAULT;
1544 if (xfer < map_len) 1544 if (xfer < map_len)
1545 break; 1545 break;
1546 } 1546 }
1547 dax_read_unlock(id); 1547 dax_read_unlock(id);
1548 1548
1549 return done ? done : ret; 1549 return done ? done : ret;
1550 } 1550 }
1551 1551
1552 /** 1552 /**
1553 * dax_iomap_rw - Perform I/O to a DAX file 1553 * dax_iomap_rw - Perform I/O to a DAX file
1554 * @iocb: The control block for this I/ 1554 * @iocb: The control block for this I/O
1555 * @iter: The addresses to do I/O from 1555 * @iter: The addresses to do I/O from or to
1556 * @ops: iomap ops passed from the fil 1556 * @ops: iomap ops passed from the file system
1557 * 1557 *
1558 * This function performs read and write oper 1558 * This function performs read and write operations to directly mapped
1559 * persistent memory. The callers needs to t 1559 * persistent memory. The callers needs to take care of read/write exclusion
1560 * and evicting any page cache pages in the r 1560 * and evicting any page cache pages in the region under I/O.
1561 */ 1561 */
1562 ssize_t 1562 ssize_t
1563 dax_iomap_rw(struct kiocb *iocb, struct iov_i 1563 dax_iomap_rw(struct kiocb *iocb, struct iov_iter *iter,
1564 const struct iomap_ops *ops) 1564 const struct iomap_ops *ops)
1565 { 1565 {
1566 struct iomap_iter iomi = { 1566 struct iomap_iter iomi = {
1567 .inode = iocb->ki_fi 1567 .inode = iocb->ki_filp->f_mapping->host,
1568 .pos = iocb->ki_po 1568 .pos = iocb->ki_pos,
1569 .len = iov_iter_co 1569 .len = iov_iter_count(iter),
1570 .flags = IOMAP_DAX, 1570 .flags = IOMAP_DAX,
1571 }; 1571 };
1572 loff_t done = 0; 1572 loff_t done = 0;
1573 int ret; 1573 int ret;
1574 1574
1575 if (!iomi.len) 1575 if (!iomi.len)
1576 return 0; 1576 return 0;
1577 1577
1578 if (iov_iter_rw(iter) == WRITE) { 1578 if (iov_iter_rw(iter) == WRITE) {
1579 lockdep_assert_held_write(&io 1579 lockdep_assert_held_write(&iomi.inode->i_rwsem);
1580 iomi.flags |= IOMAP_WRITE; 1580 iomi.flags |= IOMAP_WRITE;
1581 } else { 1581 } else {
1582 lockdep_assert_held(&iomi.ino 1582 lockdep_assert_held(&iomi.inode->i_rwsem);
1583 } 1583 }
1584 1584
1585 if (iocb->ki_flags & IOCB_NOWAIT) 1585 if (iocb->ki_flags & IOCB_NOWAIT)
1586 iomi.flags |= IOMAP_NOWAIT; 1586 iomi.flags |= IOMAP_NOWAIT;
1587 1587
1588 while ((ret = iomap_iter(&iomi, ops)) 1588 while ((ret = iomap_iter(&iomi, ops)) > 0)
1589 iomi.processed = dax_iomap_it 1589 iomi.processed = dax_iomap_iter(&iomi, iter);
1590 1590
1591 done = iomi.pos - iocb->ki_pos; 1591 done = iomi.pos - iocb->ki_pos;
1592 iocb->ki_pos = iomi.pos; 1592 iocb->ki_pos = iomi.pos;
1593 return done ? done : ret; 1593 return done ? done : ret;
1594 } 1594 }
1595 EXPORT_SYMBOL_GPL(dax_iomap_rw); 1595 EXPORT_SYMBOL_GPL(dax_iomap_rw);
1596 1596
1597 static vm_fault_t dax_fault_return(int error) 1597 static vm_fault_t dax_fault_return(int error)
1598 { 1598 {
1599 if (error == 0) 1599 if (error == 0)
1600 return VM_FAULT_NOPAGE; 1600 return VM_FAULT_NOPAGE;
1601 return vmf_error(error); 1601 return vmf_error(error);
1602 } 1602 }
1603 1603
1604 /* 1604 /*
1605 * When handling a synchronous page fault and 1605 * When handling a synchronous page fault and the inode need a fsync, we can
1606 * insert the PTE/PMD into page tables only a 1606 * insert the PTE/PMD into page tables only after that fsync happened. Skip
1607 * insertion for now and return the pfn so th 1607 * insertion for now and return the pfn so that caller can insert it after the
1608 * fsync is done. 1608 * fsync is done.
1609 */ 1609 */
1610 static vm_fault_t dax_fault_synchronous_pfnp( 1610 static vm_fault_t dax_fault_synchronous_pfnp(pfn_t *pfnp, pfn_t pfn)
1611 { 1611 {
1612 if (WARN_ON_ONCE(!pfnp)) 1612 if (WARN_ON_ONCE(!pfnp))
1613 return VM_FAULT_SIGBUS; 1613 return VM_FAULT_SIGBUS;
1614 *pfnp = pfn; 1614 *pfnp = pfn;
1615 return VM_FAULT_NEEDDSYNC; 1615 return VM_FAULT_NEEDDSYNC;
1616 } 1616 }
1617 1617
1618 static vm_fault_t dax_fault_cow_page(struct v 1618 static vm_fault_t dax_fault_cow_page(struct vm_fault *vmf,
1619 const struct iomap_iter *iter 1619 const struct iomap_iter *iter)
1620 { 1620 {
1621 vm_fault_t ret; 1621 vm_fault_t ret;
1622 int error = 0; 1622 int error = 0;
1623 1623
1624 switch (iter->iomap.type) { 1624 switch (iter->iomap.type) {
1625 case IOMAP_HOLE: 1625 case IOMAP_HOLE:
1626 case IOMAP_UNWRITTEN: 1626 case IOMAP_UNWRITTEN:
1627 clear_user_highpage(vmf->cow_ 1627 clear_user_highpage(vmf->cow_page, vmf->address);
1628 break; 1628 break;
1629 case IOMAP_MAPPED: 1629 case IOMAP_MAPPED:
1630 error = copy_cow_page_dax(vmf 1630 error = copy_cow_page_dax(vmf, iter);
1631 break; 1631 break;
1632 default: 1632 default:
1633 WARN_ON_ONCE(1); 1633 WARN_ON_ONCE(1);
1634 error = -EIO; 1634 error = -EIO;
1635 break; 1635 break;
1636 } 1636 }
1637 1637
1638 if (error) 1638 if (error)
1639 return dax_fault_return(error 1639 return dax_fault_return(error);
1640 1640
1641 __SetPageUptodate(vmf->cow_page); 1641 __SetPageUptodate(vmf->cow_page);
1642 ret = finish_fault(vmf); 1642 ret = finish_fault(vmf);
1643 if (!ret) 1643 if (!ret)
1644 return VM_FAULT_DONE_COW; 1644 return VM_FAULT_DONE_COW;
1645 return ret; 1645 return ret;
1646 } 1646 }
1647 1647
1648 /** 1648 /**
1649 * dax_fault_iter - Common actor to handle pf 1649 * dax_fault_iter - Common actor to handle pfn insertion in PTE/PMD fault.
1650 * @vmf: vm fault instance 1650 * @vmf: vm fault instance
1651 * @iter: iomap iter 1651 * @iter: iomap iter
1652 * @pfnp: pfn to be returned 1652 * @pfnp: pfn to be returned
1653 * @xas: the dax mapping tree of a fil 1653 * @xas: the dax mapping tree of a file
1654 * @entry: an unlocked dax entry to be i 1654 * @entry: an unlocked dax entry to be inserted
1655 * @pmd: distinguish whether it is a p 1655 * @pmd: distinguish whether it is a pmd fault
1656 */ 1656 */
1657 static vm_fault_t dax_fault_iter(struct vm_fa 1657 static vm_fault_t dax_fault_iter(struct vm_fault *vmf,
1658 const struct iomap_iter *iter 1658 const struct iomap_iter *iter, pfn_t *pfnp,
1659 struct xa_state *xas, void ** 1659 struct xa_state *xas, void **entry, bool pmd)
1660 { 1660 {
1661 const struct iomap *iomap = &iter->io 1661 const struct iomap *iomap = &iter->iomap;
1662 const struct iomap *srcmap = iomap_it 1662 const struct iomap *srcmap = iomap_iter_srcmap(iter);
1663 size_t size = pmd ? PMD_SIZE : PAGE_S 1663 size_t size = pmd ? PMD_SIZE : PAGE_SIZE;
1664 loff_t pos = (loff_t)xas->xa_index << 1664 loff_t pos = (loff_t)xas->xa_index << PAGE_SHIFT;
1665 bool write = iter->flags & IOMAP_WRIT 1665 bool write = iter->flags & IOMAP_WRITE;
1666 unsigned long entry_flags = pmd ? DAX 1666 unsigned long entry_flags = pmd ? DAX_PMD : 0;
1667 int err = 0; 1667 int err = 0;
1668 pfn_t pfn; 1668 pfn_t pfn;
1669 void *kaddr; 1669 void *kaddr;
1670 1670
1671 if (!pmd && vmf->cow_page) 1671 if (!pmd && vmf->cow_page)
1672 return dax_fault_cow_page(vmf 1672 return dax_fault_cow_page(vmf, iter);
1673 1673
1674 /* if we are reading UNWRITTEN and HO 1674 /* if we are reading UNWRITTEN and HOLE, return a hole. */
1675 if (!write && 1675 if (!write &&
1676 (iomap->type == IOMAP_UNWRITTEN | 1676 (iomap->type == IOMAP_UNWRITTEN || iomap->type == IOMAP_HOLE)) {
1677 if (!pmd) 1677 if (!pmd)
1678 return dax_load_hole( 1678 return dax_load_hole(xas, vmf, iter, entry);
1679 return dax_pmd_load_hole(xas, 1679 return dax_pmd_load_hole(xas, vmf, iter, entry);
1680 } 1680 }
1681 1681
1682 if (iomap->type != IOMAP_MAPPED && !( 1682 if (iomap->type != IOMAP_MAPPED && !(iomap->flags & IOMAP_F_SHARED)) {
1683 WARN_ON_ONCE(1); 1683 WARN_ON_ONCE(1);
1684 return pmd ? VM_FAULT_FALLBAC 1684 return pmd ? VM_FAULT_FALLBACK : VM_FAULT_SIGBUS;
1685 } 1685 }
1686 1686
1687 err = dax_iomap_direct_access(iomap, 1687 err = dax_iomap_direct_access(iomap, pos, size, &kaddr, &pfn);
1688 if (err) 1688 if (err)
1689 return pmd ? VM_FAULT_FALLBAC 1689 return pmd ? VM_FAULT_FALLBACK : dax_fault_return(err);
1690 1690
1691 *entry = dax_insert_entry(xas, vmf, i 1691 *entry = dax_insert_entry(xas, vmf, iter, *entry, pfn, entry_flags);
1692 1692
1693 if (write && iomap->flags & IOMAP_F_S 1693 if (write && iomap->flags & IOMAP_F_SHARED) {
1694 err = dax_iomap_copy_around(p 1694 err = dax_iomap_copy_around(pos, size, size, srcmap, kaddr);
1695 if (err) 1695 if (err)
1696 return dax_fault_retu 1696 return dax_fault_return(err);
1697 } 1697 }
1698 1698
1699 if (dax_fault_is_synchronous(iter, vm 1699 if (dax_fault_is_synchronous(iter, vmf->vma))
1700 return dax_fault_synchronous_ 1700 return dax_fault_synchronous_pfnp(pfnp, pfn);
1701 1701
1702 /* insert PMD pfn */ 1702 /* insert PMD pfn */
1703 if (pmd) 1703 if (pmd)
1704 return vmf_insert_pfn_pmd(vmf 1704 return vmf_insert_pfn_pmd(vmf, pfn, write);
1705 1705
1706 /* insert PTE pfn */ 1706 /* insert PTE pfn */
1707 if (write) 1707 if (write)
1708 return vmf_insert_mixed_mkwri 1708 return vmf_insert_mixed_mkwrite(vmf->vma, vmf->address, pfn);
1709 return vmf_insert_mixed(vmf->vma, vmf 1709 return vmf_insert_mixed(vmf->vma, vmf->address, pfn);
1710 } 1710 }
1711 1711
1712 static vm_fault_t dax_iomap_pte_fault(struct 1712 static vm_fault_t dax_iomap_pte_fault(struct vm_fault *vmf, pfn_t *pfnp,
1713 int *iomap_err 1713 int *iomap_errp, const struct iomap_ops *ops)
1714 { 1714 {
1715 struct address_space *mapping = vmf-> 1715 struct address_space *mapping = vmf->vma->vm_file->f_mapping;
1716 XA_STATE(xas, &mapping->i_pages, vmf- 1716 XA_STATE(xas, &mapping->i_pages, vmf->pgoff);
1717 struct iomap_iter iter = { 1717 struct iomap_iter iter = {
1718 .inode = mapping->ho 1718 .inode = mapping->host,
1719 .pos = (loff_t)vmf 1719 .pos = (loff_t)vmf->pgoff << PAGE_SHIFT,
1720 .len = PAGE_SIZE, 1720 .len = PAGE_SIZE,
1721 .flags = IOMAP_DAX | 1721 .flags = IOMAP_DAX | IOMAP_FAULT,
1722 }; 1722 };
1723 vm_fault_t ret = 0; 1723 vm_fault_t ret = 0;
1724 void *entry; 1724 void *entry;
1725 int error; 1725 int error;
1726 1726
1727 trace_dax_pte_fault(iter.inode, vmf, 1727 trace_dax_pte_fault(iter.inode, vmf, ret);
1728 /* 1728 /*
1729 * Check whether offset isn't beyond 1729 * Check whether offset isn't beyond end of file now. Caller is supposed
1730 * to hold locks serializing us with 1730 * to hold locks serializing us with truncate / punch hole so this is
1731 * a reliable test. 1731 * a reliable test.
1732 */ 1732 */
1733 if (iter.pos >= i_size_read(iter.inod 1733 if (iter.pos >= i_size_read(iter.inode)) {
1734 ret = VM_FAULT_SIGBUS; 1734 ret = VM_FAULT_SIGBUS;
1735 goto out; 1735 goto out;
1736 } 1736 }
1737 1737
1738 if ((vmf->flags & FAULT_FLAG_WRITE) & 1738 if ((vmf->flags & FAULT_FLAG_WRITE) && !vmf->cow_page)
1739 iter.flags |= IOMAP_WRITE; 1739 iter.flags |= IOMAP_WRITE;
1740 1740
1741 entry = grab_mapping_entry(&xas, mapp 1741 entry = grab_mapping_entry(&xas, mapping, 0);
1742 if (xa_is_internal(entry)) { 1742 if (xa_is_internal(entry)) {
1743 ret = xa_to_internal(entry); 1743 ret = xa_to_internal(entry);
1744 goto out; 1744 goto out;
1745 } 1745 }
1746 1746
1747 /* 1747 /*
1748 * It is possible, particularly with 1748 * It is possible, particularly with mixed reads & writes to private
1749 * mappings, that we have raced with 1749 * mappings, that we have raced with a PMD fault that overlaps with
1750 * the PTE we need to set up. If so 1750 * the PTE we need to set up. If so just return and the fault will be
1751 * retried. 1751 * retried.
1752 */ 1752 */
1753 if (pmd_trans_huge(*vmf->pmd) || pmd_ 1753 if (pmd_trans_huge(*vmf->pmd) || pmd_devmap(*vmf->pmd)) {
1754 ret = VM_FAULT_NOPAGE; 1754 ret = VM_FAULT_NOPAGE;
1755 goto unlock_entry; 1755 goto unlock_entry;
1756 } 1756 }
1757 1757
1758 while ((error = iomap_iter(&iter, ops 1758 while ((error = iomap_iter(&iter, ops)) > 0) {
1759 if (WARN_ON_ONCE(iomap_length 1759 if (WARN_ON_ONCE(iomap_length(&iter) < PAGE_SIZE)) {
1760 iter.processed = -EIO 1760 iter.processed = -EIO; /* fs corruption? */
1761 continue; 1761 continue;
1762 } 1762 }
1763 1763
1764 ret = dax_fault_iter(vmf, &it 1764 ret = dax_fault_iter(vmf, &iter, pfnp, &xas, &entry, false);
1765 if (ret != VM_FAULT_SIGBUS && 1765 if (ret != VM_FAULT_SIGBUS &&
1766 (iter.iomap.flags & IOMAP 1766 (iter.iomap.flags & IOMAP_F_NEW)) {
1767 count_vm_event(PGMAJF 1767 count_vm_event(PGMAJFAULT);
1768 count_memcg_event_mm( 1768 count_memcg_event_mm(vmf->vma->vm_mm, PGMAJFAULT);
1769 ret |= VM_FAULT_MAJOR 1769 ret |= VM_FAULT_MAJOR;
1770 } 1770 }
1771 1771
1772 if (!(ret & VM_FAULT_ERROR)) 1772 if (!(ret & VM_FAULT_ERROR))
1773 iter.processed = PAGE 1773 iter.processed = PAGE_SIZE;
1774 } 1774 }
1775 1775
1776 if (iomap_errp) 1776 if (iomap_errp)
1777 *iomap_errp = error; 1777 *iomap_errp = error;
1778 if (!ret && error) 1778 if (!ret && error)
1779 ret = dax_fault_return(error) 1779 ret = dax_fault_return(error);
1780 1780
1781 unlock_entry: 1781 unlock_entry:
1782 dax_unlock_entry(&xas, entry); 1782 dax_unlock_entry(&xas, entry);
1783 out: 1783 out:
1784 trace_dax_pte_fault_done(iter.inode, 1784 trace_dax_pte_fault_done(iter.inode, vmf, ret);
1785 return ret; 1785 return ret;
1786 } 1786 }
1787 1787
1788 #ifdef CONFIG_FS_DAX_PMD 1788 #ifdef CONFIG_FS_DAX_PMD
1789 static bool dax_fault_check_fallback(struct v 1789 static bool dax_fault_check_fallback(struct vm_fault *vmf, struct xa_state *xas,
1790 pgoff_t max_pgoff) 1790 pgoff_t max_pgoff)
1791 { 1791 {
1792 unsigned long pmd_addr = vmf->address 1792 unsigned long pmd_addr = vmf->address & PMD_MASK;
1793 bool write = vmf->flags & FAULT_FLAG_ 1793 bool write = vmf->flags & FAULT_FLAG_WRITE;
1794 1794
1795 /* 1795 /*
1796 * Make sure that the faulting addres 1796 * Make sure that the faulting address's PMD offset (color) matches
1797 * the PMD offset from the start of t 1797 * the PMD offset from the start of the file. This is necessary so
1798 * that a PMD range in the page table 1798 * that a PMD range in the page table overlaps exactly with a PMD
1799 * range in the page cache. 1799 * range in the page cache.
1800 */ 1800 */
1801 if ((vmf->pgoff & PG_PMD_COLOUR) != 1801 if ((vmf->pgoff & PG_PMD_COLOUR) !=
1802 ((vmf->address >> PAGE_SHIFT) & P 1802 ((vmf->address >> PAGE_SHIFT) & PG_PMD_COLOUR))
1803 return true; 1803 return true;
1804 1804
1805 /* Fall back to PTEs if we're going t 1805 /* Fall back to PTEs if we're going to COW */
1806 if (write && !(vmf->vma->vm_flags & V 1806 if (write && !(vmf->vma->vm_flags & VM_SHARED))
1807 return true; 1807 return true;
1808 1808
1809 /* If the PMD would extend outside th 1809 /* If the PMD would extend outside the VMA */
1810 if (pmd_addr < vmf->vma->vm_start) 1810 if (pmd_addr < vmf->vma->vm_start)
1811 return true; 1811 return true;
1812 if ((pmd_addr + PMD_SIZE) > vmf->vma- 1812 if ((pmd_addr + PMD_SIZE) > vmf->vma->vm_end)
1813 return true; 1813 return true;
1814 1814
1815 /* If the PMD would extend beyond the 1815 /* If the PMD would extend beyond the file size */
1816 if ((xas->xa_index | PG_PMD_COLOUR) > 1816 if ((xas->xa_index | PG_PMD_COLOUR) >= max_pgoff)
1817 return true; 1817 return true;
1818 1818
1819 return false; 1819 return false;
1820 } 1820 }
1821 1821
1822 static vm_fault_t dax_iomap_pmd_fault(struct 1822 static vm_fault_t dax_iomap_pmd_fault(struct vm_fault *vmf, pfn_t *pfnp,
1823 const struct i 1823 const struct iomap_ops *ops)
1824 { 1824 {
1825 struct address_space *mapping = vmf-> 1825 struct address_space *mapping = vmf->vma->vm_file->f_mapping;
1826 XA_STATE_ORDER(xas, &mapping->i_pages 1826 XA_STATE_ORDER(xas, &mapping->i_pages, vmf->pgoff, PMD_ORDER);
1827 struct iomap_iter iter = { 1827 struct iomap_iter iter = {
1828 .inode = mapping->ho 1828 .inode = mapping->host,
1829 .len = PMD_SIZE, 1829 .len = PMD_SIZE,
1830 .flags = IOMAP_DAX | 1830 .flags = IOMAP_DAX | IOMAP_FAULT,
1831 }; 1831 };
1832 vm_fault_t ret = VM_FAULT_FALLBACK; 1832 vm_fault_t ret = VM_FAULT_FALLBACK;
1833 pgoff_t max_pgoff; 1833 pgoff_t max_pgoff;
1834 void *entry; 1834 void *entry;
1835 1835
1836 if (vmf->flags & FAULT_FLAG_WRITE) 1836 if (vmf->flags & FAULT_FLAG_WRITE)
1837 iter.flags |= IOMAP_WRITE; 1837 iter.flags |= IOMAP_WRITE;
1838 1838
1839 /* 1839 /*
1840 * Check whether offset isn't beyond 1840 * Check whether offset isn't beyond end of file now. Caller is
1841 * supposed to hold locks serializing 1841 * supposed to hold locks serializing us with truncate / punch hole so
1842 * this is a reliable test. 1842 * this is a reliable test.
1843 */ 1843 */
1844 max_pgoff = DIV_ROUND_UP(i_size_read( 1844 max_pgoff = DIV_ROUND_UP(i_size_read(iter.inode), PAGE_SIZE);
1845 1845
1846 trace_dax_pmd_fault(iter.inode, vmf, 1846 trace_dax_pmd_fault(iter.inode, vmf, max_pgoff, 0);
1847 1847
1848 if (xas.xa_index >= max_pgoff) { 1848 if (xas.xa_index >= max_pgoff) {
1849 ret = VM_FAULT_SIGBUS; 1849 ret = VM_FAULT_SIGBUS;
1850 goto out; 1850 goto out;
1851 } 1851 }
1852 1852
1853 if (dax_fault_check_fallback(vmf, &xa 1853 if (dax_fault_check_fallback(vmf, &xas, max_pgoff))
1854 goto fallback; 1854 goto fallback;
1855 1855
1856 /* 1856 /*
1857 * grab_mapping_entry() will make sur 1857 * grab_mapping_entry() will make sure we get an empty PMD entry,
1858 * a zero PMD entry or a DAX PMD. If 1858 * a zero PMD entry or a DAX PMD. If it can't (because a PTE
1859 * entry is already in the array, for 1859 * entry is already in the array, for instance), it will return
1860 * VM_FAULT_FALLBACK. 1860 * VM_FAULT_FALLBACK.
1861 */ 1861 */
1862 entry = grab_mapping_entry(&xas, mapp 1862 entry = grab_mapping_entry(&xas, mapping, PMD_ORDER);
1863 if (xa_is_internal(entry)) { 1863 if (xa_is_internal(entry)) {
1864 ret = xa_to_internal(entry); 1864 ret = xa_to_internal(entry);
1865 goto fallback; 1865 goto fallback;
1866 } 1866 }
1867 1867
1868 /* 1868 /*
1869 * It is possible, particularly with 1869 * It is possible, particularly with mixed reads & writes to private
1870 * mappings, that we have raced with 1870 * mappings, that we have raced with a PTE fault that overlaps with
1871 * the PMD we need to set up. If so 1871 * the PMD we need to set up. If so just return and the fault will be
1872 * retried. 1872 * retried.
1873 */ 1873 */
1874 if (!pmd_none(*vmf->pmd) && !pmd_tran 1874 if (!pmd_none(*vmf->pmd) && !pmd_trans_huge(*vmf->pmd) &&
1875 !pmd_devmap(*vmf->pmd 1875 !pmd_devmap(*vmf->pmd)) {
1876 ret = 0; 1876 ret = 0;
1877 goto unlock_entry; 1877 goto unlock_entry;
1878 } 1878 }
1879 1879
1880 iter.pos = (loff_t)xas.xa_index << PA 1880 iter.pos = (loff_t)xas.xa_index << PAGE_SHIFT;
1881 while (iomap_iter(&iter, ops) > 0) { 1881 while (iomap_iter(&iter, ops) > 0) {
1882 if (iomap_length(&iter) < PMD 1882 if (iomap_length(&iter) < PMD_SIZE)
1883 continue; /* actually 1883 continue; /* actually breaks out of the loop */
1884 1884
1885 ret = dax_fault_iter(vmf, &it 1885 ret = dax_fault_iter(vmf, &iter, pfnp, &xas, &entry, true);
1886 if (ret != VM_FAULT_FALLBACK) 1886 if (ret != VM_FAULT_FALLBACK)
1887 iter.processed = PMD_ 1887 iter.processed = PMD_SIZE;
1888 } 1888 }
1889 1889
1890 unlock_entry: 1890 unlock_entry:
1891 dax_unlock_entry(&xas, entry); 1891 dax_unlock_entry(&xas, entry);
1892 fallback: 1892 fallback:
1893 if (ret == VM_FAULT_FALLBACK) { 1893 if (ret == VM_FAULT_FALLBACK) {
1894 split_huge_pmd(vmf->vma, vmf- 1894 split_huge_pmd(vmf->vma, vmf->pmd, vmf->address);
1895 count_vm_event(THP_FAULT_FALL 1895 count_vm_event(THP_FAULT_FALLBACK);
1896 } 1896 }
1897 out: 1897 out:
1898 trace_dax_pmd_fault_done(iter.inode, 1898 trace_dax_pmd_fault_done(iter.inode, vmf, max_pgoff, ret);
1899 return ret; 1899 return ret;
1900 } 1900 }
1901 #else 1901 #else
1902 static vm_fault_t dax_iomap_pmd_fault(struct 1902 static vm_fault_t dax_iomap_pmd_fault(struct vm_fault *vmf, pfn_t *pfnp,
1903 const struct i 1903 const struct iomap_ops *ops)
1904 { 1904 {
1905 return VM_FAULT_FALLBACK; 1905 return VM_FAULT_FALLBACK;
1906 } 1906 }
1907 #endif /* CONFIG_FS_DAX_PMD */ 1907 #endif /* CONFIG_FS_DAX_PMD */
1908 1908
1909 /** 1909 /**
1910 * dax_iomap_fault - handle a page fault on a 1910 * dax_iomap_fault - handle a page fault on a DAX file
1911 * @vmf: The description of the fault 1911 * @vmf: The description of the fault
1912 * @order: Order of the page to fault in 1912 * @order: Order of the page to fault in
1913 * @pfnp: PFN to insert for synchronous fault 1913 * @pfnp: PFN to insert for synchronous faults if fsync is required
1914 * @iomap_errp: Storage for detailed error co 1914 * @iomap_errp: Storage for detailed error code in case of error
1915 * @ops: Iomap ops passed from the file syste 1915 * @ops: Iomap ops passed from the file system
1916 * 1916 *
1917 * When a page fault occurs, filesystems may 1917 * When a page fault occurs, filesystems may call this helper in
1918 * their fault handler for DAX files. dax_iom 1918 * their fault handler for DAX files. dax_iomap_fault() assumes the caller
1919 * has done all the necessary locking for pag 1919 * has done all the necessary locking for page fault to proceed
1920 * successfully. 1920 * successfully.
1921 */ 1921 */
1922 vm_fault_t dax_iomap_fault(struct vm_fault *v 1922 vm_fault_t dax_iomap_fault(struct vm_fault *vmf, unsigned int order,
1923 pfn_t *pfnp, int *iomap_e 1923 pfn_t *pfnp, int *iomap_errp, const struct iomap_ops *ops)
1924 { 1924 {
1925 if (order == 0) 1925 if (order == 0)
1926 return dax_iomap_pte_fault(vm 1926 return dax_iomap_pte_fault(vmf, pfnp, iomap_errp, ops);
1927 else if (order == PMD_ORDER) 1927 else if (order == PMD_ORDER)
1928 return dax_iomap_pmd_fault(vm 1928 return dax_iomap_pmd_fault(vmf, pfnp, ops);
1929 else 1929 else
1930 return VM_FAULT_FALLBACK; 1930 return VM_FAULT_FALLBACK;
1931 } 1931 }
1932 EXPORT_SYMBOL_GPL(dax_iomap_fault); 1932 EXPORT_SYMBOL_GPL(dax_iomap_fault);
1933 1933
1934 /* 1934 /*
1935 * dax_insert_pfn_mkwrite - insert PTE or PMD 1935 * dax_insert_pfn_mkwrite - insert PTE or PMD entry into page tables
1936 * @vmf: The description of the fault 1936 * @vmf: The description of the fault
1937 * @pfn: PFN to insert 1937 * @pfn: PFN to insert
1938 * @order: Order of entry to insert. 1938 * @order: Order of entry to insert.
1939 * 1939 *
1940 * This function inserts a writeable PTE or P 1940 * This function inserts a writeable PTE or PMD entry into the page tables
1941 * for an mmaped DAX file. It also marks the 1941 * for an mmaped DAX file. It also marks the page cache entry as dirty.
1942 */ 1942 */
1943 static vm_fault_t 1943 static vm_fault_t
1944 dax_insert_pfn_mkwrite(struct vm_fault *vmf, 1944 dax_insert_pfn_mkwrite(struct vm_fault *vmf, pfn_t pfn, unsigned int order)
1945 { 1945 {
1946 struct address_space *mapping = vmf-> 1946 struct address_space *mapping = vmf->vma->vm_file->f_mapping;
1947 XA_STATE_ORDER(xas, &mapping->i_pages 1947 XA_STATE_ORDER(xas, &mapping->i_pages, vmf->pgoff, order);
1948 void *entry; 1948 void *entry;
1949 vm_fault_t ret; 1949 vm_fault_t ret;
1950 1950
1951 xas_lock_irq(&xas); 1951 xas_lock_irq(&xas);
1952 entry = get_unlocked_entry(&xas, orde 1952 entry = get_unlocked_entry(&xas, order);
1953 /* Did we race with someone splitting 1953 /* Did we race with someone splitting entry or so? */
1954 if (!entry || dax_is_conflict(entry) 1954 if (!entry || dax_is_conflict(entry) ||
1955 (order == 0 && !dax_is_pte_entry( 1955 (order == 0 && !dax_is_pte_entry(entry))) {
1956 put_unlocked_entry(&xas, entr 1956 put_unlocked_entry(&xas, entry, WAKE_NEXT);
1957 xas_unlock_irq(&xas); 1957 xas_unlock_irq(&xas);
1958 trace_dax_insert_pfn_mkwrite_ 1958 trace_dax_insert_pfn_mkwrite_no_entry(mapping->host, vmf,
1959 1959 VM_FAULT_NOPAGE);
1960 return VM_FAULT_NOPAGE; 1960 return VM_FAULT_NOPAGE;
1961 } 1961 }
1962 xas_set_mark(&xas, PAGECACHE_TAG_DIRT 1962 xas_set_mark(&xas, PAGECACHE_TAG_DIRTY);
1963 dax_lock_entry(&xas, entry); 1963 dax_lock_entry(&xas, entry);
1964 xas_unlock_irq(&xas); 1964 xas_unlock_irq(&xas);
1965 if (order == 0) 1965 if (order == 0)
1966 ret = vmf_insert_mixed_mkwrit 1966 ret = vmf_insert_mixed_mkwrite(vmf->vma, vmf->address, pfn);
1967 #ifdef CONFIG_FS_DAX_PMD 1967 #ifdef CONFIG_FS_DAX_PMD
1968 else if (order == PMD_ORDER) 1968 else if (order == PMD_ORDER)
1969 ret = vmf_insert_pfn_pmd(vmf, 1969 ret = vmf_insert_pfn_pmd(vmf, pfn, FAULT_FLAG_WRITE);
1970 #endif 1970 #endif
1971 else 1971 else
1972 ret = VM_FAULT_FALLBACK; 1972 ret = VM_FAULT_FALLBACK;
1973 dax_unlock_entry(&xas, entry); 1973 dax_unlock_entry(&xas, entry);
1974 trace_dax_insert_pfn_mkwrite(mapping- 1974 trace_dax_insert_pfn_mkwrite(mapping->host, vmf, ret);
1975 return ret; 1975 return ret;
1976 } 1976 }
1977 1977
1978 /** 1978 /**
1979 * dax_finish_sync_fault - finish synchronous 1979 * dax_finish_sync_fault - finish synchronous page fault
1980 * @vmf: The description of the fault 1980 * @vmf: The description of the fault
1981 * @order: Order of entry to be inserted 1981 * @order: Order of entry to be inserted
1982 * @pfn: PFN to insert 1982 * @pfn: PFN to insert
1983 * 1983 *
1984 * This function ensures that the file range 1984 * This function ensures that the file range touched by the page fault is
1985 * stored persistently on the media and handl 1985 * stored persistently on the media and handles inserting of appropriate page
1986 * table entry. 1986 * table entry.
1987 */ 1987 */
1988 vm_fault_t dax_finish_sync_fault(struct vm_fa 1988 vm_fault_t dax_finish_sync_fault(struct vm_fault *vmf, unsigned int order,
1989 pfn_t pfn) 1989 pfn_t pfn)
1990 { 1990 {
1991 int err; 1991 int err;
1992 loff_t start = ((loff_t)vmf->pgoff) < 1992 loff_t start = ((loff_t)vmf->pgoff) << PAGE_SHIFT;
1993 size_t len = PAGE_SIZE << order; 1993 size_t len = PAGE_SIZE << order;
1994 1994
1995 err = vfs_fsync_range(vmf->vma->vm_fi 1995 err = vfs_fsync_range(vmf->vma->vm_file, start, start + len - 1, 1);
1996 if (err) 1996 if (err)
1997 return VM_FAULT_SIGBUS; 1997 return VM_FAULT_SIGBUS;
1998 return dax_insert_pfn_mkwrite(vmf, pf 1998 return dax_insert_pfn_mkwrite(vmf, pfn, order);
1999 } 1999 }
2000 EXPORT_SYMBOL_GPL(dax_finish_sync_fault); 2000 EXPORT_SYMBOL_GPL(dax_finish_sync_fault);
2001 2001
2002 static loff_t dax_range_compare_iter(struct i 2002 static loff_t dax_range_compare_iter(struct iomap_iter *it_src,
2003 struct iomap_iter *it_dest, u 2003 struct iomap_iter *it_dest, u64 len, bool *same)
2004 { 2004 {
2005 const struct iomap *smap = &it_src->i 2005 const struct iomap *smap = &it_src->iomap;
2006 const struct iomap *dmap = &it_dest-> 2006 const struct iomap *dmap = &it_dest->iomap;
2007 loff_t pos1 = it_src->pos, pos2 = it_ 2007 loff_t pos1 = it_src->pos, pos2 = it_dest->pos;
2008 void *saddr, *daddr; 2008 void *saddr, *daddr;
2009 int id, ret; 2009 int id, ret;
2010 2010
2011 len = min(len, min(smap->length, dmap 2011 len = min(len, min(smap->length, dmap->length));
2012 2012
2013 if (smap->type == IOMAP_HOLE && dmap- 2013 if (smap->type == IOMAP_HOLE && dmap->type == IOMAP_HOLE) {
2014 *same = true; 2014 *same = true;
2015 return len; 2015 return len;
2016 } 2016 }
2017 2017
2018 if (smap->type == IOMAP_HOLE || dmap- 2018 if (smap->type == IOMAP_HOLE || dmap->type == IOMAP_HOLE) {
2019 *same = false; 2019 *same = false;
2020 return 0; 2020 return 0;
2021 } 2021 }
2022 2022
2023 id = dax_read_lock(); 2023 id = dax_read_lock();
2024 ret = dax_iomap_direct_access(smap, p 2024 ret = dax_iomap_direct_access(smap, pos1, ALIGN(pos1 + len, PAGE_SIZE),
2025 &saddr, 2025 &saddr, NULL);
2026 if (ret < 0) 2026 if (ret < 0)
2027 goto out_unlock; 2027 goto out_unlock;
2028 2028
2029 ret = dax_iomap_direct_access(dmap, p 2029 ret = dax_iomap_direct_access(dmap, pos2, ALIGN(pos2 + len, PAGE_SIZE),
2030 &daddr, 2030 &daddr, NULL);
2031 if (ret < 0) 2031 if (ret < 0)
2032 goto out_unlock; 2032 goto out_unlock;
2033 2033
2034 *same = !memcmp(saddr, daddr, len); 2034 *same = !memcmp(saddr, daddr, len);
2035 if (!*same) 2035 if (!*same)
2036 len = 0; 2036 len = 0;
2037 dax_read_unlock(id); 2037 dax_read_unlock(id);
2038 return len; 2038 return len;
2039 2039
2040 out_unlock: 2040 out_unlock:
2041 dax_read_unlock(id); 2041 dax_read_unlock(id);
2042 return -EIO; 2042 return -EIO;
2043 } 2043 }
2044 2044
2045 int dax_dedupe_file_range_compare(struct inod 2045 int dax_dedupe_file_range_compare(struct inode *src, loff_t srcoff,
2046 struct inode *dst, loff_t dst 2046 struct inode *dst, loff_t dstoff, loff_t len, bool *same,
2047 const struct iomap_ops *ops) 2047 const struct iomap_ops *ops)
2048 { 2048 {
2049 struct iomap_iter src_iter = { 2049 struct iomap_iter src_iter = {
2050 .inode = src, 2050 .inode = src,
2051 .pos = srcoff, 2051 .pos = srcoff,
2052 .len = len, 2052 .len = len,
2053 .flags = IOMAP_DAX, 2053 .flags = IOMAP_DAX,
2054 }; 2054 };
2055 struct iomap_iter dst_iter = { 2055 struct iomap_iter dst_iter = {
2056 .inode = dst, 2056 .inode = dst,
2057 .pos = dstoff, 2057 .pos = dstoff,
2058 .len = len, 2058 .len = len,
2059 .flags = IOMAP_DAX, 2059 .flags = IOMAP_DAX,
2060 }; 2060 };
2061 int ret, compared = 0; 2061 int ret, compared = 0;
2062 2062
2063 while ((ret = iomap_iter(&src_iter, o 2063 while ((ret = iomap_iter(&src_iter, ops)) > 0 &&
2064 (ret = iomap_iter(&dst_iter, o 2064 (ret = iomap_iter(&dst_iter, ops)) > 0) {
2065 compared = dax_range_compare_ 2065 compared = dax_range_compare_iter(&src_iter, &dst_iter,
2066 min(src_iter. 2066 min(src_iter.len, dst_iter.len), same);
2067 if (compared < 0) 2067 if (compared < 0)
2068 return ret; 2068 return ret;
2069 src_iter.processed = dst_iter 2069 src_iter.processed = dst_iter.processed = compared;
2070 } 2070 }
2071 return ret; 2071 return ret;
2072 } 2072 }
2073 2073
2074 int dax_remap_file_range_prep(struct file *fi 2074 int dax_remap_file_range_prep(struct file *file_in, loff_t pos_in,
2075 struct file *fi 2075 struct file *file_out, loff_t pos_out,
2076 loff_t *len, un 2076 loff_t *len, unsigned int remap_flags,
2077 const struct io 2077 const struct iomap_ops *ops)
2078 { 2078 {
2079 return __generic_remap_file_range_pre 2079 return __generic_remap_file_range_prep(file_in, pos_in, file_out,
2080 2080 pos_out, len, remap_flags, ops);
2081 } 2081 }
2082 EXPORT_SYMBOL_GPL(dax_remap_file_range_prep); 2082 EXPORT_SYMBOL_GPL(dax_remap_file_range_prep);
2083 2083
Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.