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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * dax: direct host memory access
4 * Copyright (C) 2020 Red Hat, Inc.
5 */
6
7#include "fuse_i.h"
8
9#include <linux/delay.h>
10#include <linux/dax.h>
11#include <linux/uio.h>
12#include <linux/pagemap.h>
13#include <linux/pfn_t.h>
14#include <linux/iomap.h>
15#include <linux/interval_tree.h>
16
17/*
18 * Default memory range size. A power of 2 so it agrees with common FUSE_INIT
19 * map_alignment values 4KB and 64KB.
20 */
21#define FUSE_DAX_SHIFT 21
22#define FUSE_DAX_SZ (1 << FUSE_DAX_SHIFT)
23#define FUSE_DAX_PAGES (FUSE_DAX_SZ / PAGE_SIZE)
24
25/* Number of ranges reclaimer will try to free in one invocation */
26#define FUSE_DAX_RECLAIM_CHUNK (10)
27
28/*
29 * Dax memory reclaim threshold in percetage of total ranges. When free
30 * number of free ranges drops below this threshold, reclaim can trigger
31 * Default is 20%
32 */
33#define FUSE_DAX_RECLAIM_THRESHOLD (20)
34
35/** Translation information for file offsets to DAX window offsets */
36struct fuse_dax_mapping {
37 /* Pointer to inode where this memory range is mapped */
38 struct inode *inode;
39
40 /* Will connect in fcd->free_ranges to keep track of free memory */
41 struct list_head list;
42
43 /* For interval tree in file/inode */
44 struct interval_tree_node itn;
45
46 /* Will connect in fc->busy_ranges to keep track busy memory */
47 struct list_head busy_list;
48
49 /** Position in DAX window */
50 u64 window_offset;
51
52 /** Length of mapping, in bytes */
53 loff_t length;
54
55 /* Is this mapping read-only or read-write */
56 bool writable;
57
58 /* reference count when the mapping is used by dax iomap. */
59 refcount_t refcnt;
60};
61
62/* Per-inode dax map */
63struct fuse_inode_dax {
64 /* Semaphore to protect modifications to the dmap tree */
65 struct rw_semaphore sem;
66
67 /* Sorted rb tree of struct fuse_dax_mapping elements */
68 struct rb_root_cached tree;
69 unsigned long nr;
70};
71
72struct fuse_conn_dax {
73 /* DAX device */
74 struct dax_device *dev;
75
76 /* Lock protecting accessess to members of this structure */
77 spinlock_t lock;
78
79 /* List of memory ranges which are busy */
80 unsigned long nr_busy_ranges;
81 struct list_head busy_ranges;
82
83 /* Worker to free up memory ranges */
84 struct delayed_work free_work;
85
86 /* Wait queue for a dax range to become free */
87 wait_queue_head_t range_waitq;
88
89 /* DAX Window Free Ranges */
90 long nr_free_ranges;
91 struct list_head free_ranges;
92
93 unsigned long nr_ranges;
94};
95
96static inline struct fuse_dax_mapping *
97node_to_dmap(struct interval_tree_node *node)
98{
99 if (!node)
100 return NULL;
101
102 return container_of(node, struct fuse_dax_mapping, itn);
103}
104
105static struct fuse_dax_mapping *
106alloc_dax_mapping_reclaim(struct fuse_conn_dax *fcd, struct inode *inode);
107
108static void
109__kick_dmap_free_worker(struct fuse_conn_dax *fcd, unsigned long delay_ms)
110{
111 unsigned long free_threshold;
112
113 /* If number of free ranges are below threshold, start reclaim */
114 free_threshold = max_t(unsigned long, fcd->nr_ranges * FUSE_DAX_RECLAIM_THRESHOLD / 100,
115 1);
116 if (fcd->nr_free_ranges < free_threshold)
117 queue_delayed_work(system_long_wq, &fcd->free_work,
118 msecs_to_jiffies(delay_ms));
119}
120
121static void kick_dmap_free_worker(struct fuse_conn_dax *fcd,
122 unsigned long delay_ms)
123{
124 spin_lock(&fcd->lock);
125 __kick_dmap_free_worker(fcd, delay_ms);
126 spin_unlock(&fcd->lock);
127}
128
129static struct fuse_dax_mapping *alloc_dax_mapping(struct fuse_conn_dax *fcd)
130{
131 struct fuse_dax_mapping *dmap;
132
133 spin_lock(&fcd->lock);
134 dmap = list_first_entry_or_null(&fcd->free_ranges,
135 struct fuse_dax_mapping, list);
136 if (dmap) {
137 list_del_init(&dmap->list);
138 WARN_ON(fcd->nr_free_ranges <= 0);
139 fcd->nr_free_ranges--;
140 }
141 __kick_dmap_free_worker(fcd, 0);
142 spin_unlock(&fcd->lock);
143
144 return dmap;
145}
146
147/* This assumes fcd->lock is held */
148static void __dmap_remove_busy_list(struct fuse_conn_dax *fcd,
149 struct fuse_dax_mapping *dmap)
150{
151 list_del_init(&dmap->busy_list);
152 WARN_ON(fcd->nr_busy_ranges == 0);
153 fcd->nr_busy_ranges--;
154}
155
156static void dmap_remove_busy_list(struct fuse_conn_dax *fcd,
157 struct fuse_dax_mapping *dmap)
158{
159 spin_lock(&fcd->lock);
160 __dmap_remove_busy_list(fcd, dmap);
161 spin_unlock(&fcd->lock);
162}
163
164/* This assumes fcd->lock is held */
165static void __dmap_add_to_free_pool(struct fuse_conn_dax *fcd,
166 struct fuse_dax_mapping *dmap)
167{
168 list_add_tail(&dmap->list, &fcd->free_ranges);
169 fcd->nr_free_ranges++;
170 wake_up(&fcd->range_waitq);
171}
172
173static void dmap_add_to_free_pool(struct fuse_conn_dax *fcd,
174 struct fuse_dax_mapping *dmap)
175{
176 /* Return fuse_dax_mapping to free list */
177 spin_lock(&fcd->lock);
178 __dmap_add_to_free_pool(fcd, dmap);
179 spin_unlock(&fcd->lock);
180}
181
182static int fuse_setup_one_mapping(struct inode *inode, unsigned long start_idx,
183 struct fuse_dax_mapping *dmap, bool writable,
184 bool upgrade)
185{
186 struct fuse_mount *fm = get_fuse_mount(inode);
187 struct fuse_conn_dax *fcd = fm->fc->dax;
188 struct fuse_inode *fi = get_fuse_inode(inode);
189 struct fuse_setupmapping_in inarg;
190 loff_t offset = start_idx << FUSE_DAX_SHIFT;
191 FUSE_ARGS(args);
192 ssize_t err;
193
194 WARN_ON(fcd->nr_free_ranges < 0);
195
196 /* Ask fuse daemon to setup mapping */
197 memset(&inarg, 0, sizeof(inarg));
198 inarg.foffset = offset;
199 inarg.fh = -1;
200 inarg.moffset = dmap->window_offset;
201 inarg.len = FUSE_DAX_SZ;
202 inarg.flags |= FUSE_SETUPMAPPING_FLAG_READ;
203 if (writable)
204 inarg.flags |= FUSE_SETUPMAPPING_FLAG_WRITE;
205 args.opcode = FUSE_SETUPMAPPING;
206 args.nodeid = fi->nodeid;
207 args.in_numargs = 1;
208 args.in_args[0].size = sizeof(inarg);
209 args.in_args[0].value = &inarg;
210 err = fuse_simple_request(fm, &args);
211 if (err < 0)
212 return err;
213 dmap->writable = writable;
214 if (!upgrade) {
215 /*
216 * We don't take a reference on inode. inode is valid right now
217 * and when inode is going away, cleanup logic should first
218 * cleanup dmap entries.
219 */
220 dmap->inode = inode;
221 dmap->itn.start = dmap->itn.last = start_idx;
222 /* Protected by fi->dax->sem */
223 interval_tree_insert(&dmap->itn, &fi->dax->tree);
224 fi->dax->nr++;
225 spin_lock(&fcd->lock);
226 list_add_tail(&dmap->busy_list, &fcd->busy_ranges);
227 fcd->nr_busy_ranges++;
228 spin_unlock(&fcd->lock);
229 }
230 return 0;
231}
232
233static int fuse_send_removemapping(struct inode *inode,
234 struct fuse_removemapping_in *inargp,
235 struct fuse_removemapping_one *remove_one)
236{
237 struct fuse_inode *fi = get_fuse_inode(inode);
238 struct fuse_mount *fm = get_fuse_mount(inode);
239 FUSE_ARGS(args);
240
241 args.opcode = FUSE_REMOVEMAPPING;
242 args.nodeid = fi->nodeid;
243 args.in_numargs = 2;
244 args.in_args[0].size = sizeof(*inargp);
245 args.in_args[0].value = inargp;
246 args.in_args[1].size = inargp->count * sizeof(*remove_one);
247 args.in_args[1].value = remove_one;
248 return fuse_simple_request(fm, &args);
249}
250
251static int dmap_removemapping_list(struct inode *inode, unsigned int num,
252 struct list_head *to_remove)
253{
254 struct fuse_removemapping_one *remove_one, *ptr;
255 struct fuse_removemapping_in inarg;
256 struct fuse_dax_mapping *dmap;
257 int ret, i = 0, nr_alloc;
258
259 nr_alloc = min_t(unsigned int, num, FUSE_REMOVEMAPPING_MAX_ENTRY);
260 remove_one = kmalloc_array(nr_alloc, sizeof(*remove_one), GFP_NOFS);
261 if (!remove_one)
262 return -ENOMEM;
263
264 ptr = remove_one;
265 list_for_each_entry(dmap, to_remove, list) {
266 ptr->moffset = dmap->window_offset;
267 ptr->len = dmap->length;
268 ptr++;
269 i++;
270 num--;
271 if (i >= nr_alloc || num == 0) {
272 memset(&inarg, 0, sizeof(inarg));
273 inarg.count = i;
274 ret = fuse_send_removemapping(inode, &inarg,
275 remove_one);
276 if (ret)
277 goto out;
278 ptr = remove_one;
279 i = 0;
280 }
281 }
282out:
283 kfree(remove_one);
284 return ret;
285}
286
287/*
288 * Cleanup dmap entry and add back to free list. This should be called with
289 * fcd->lock held.
290 */
291static void dmap_reinit_add_to_free_pool(struct fuse_conn_dax *fcd,
292 struct fuse_dax_mapping *dmap)
293{
294 pr_debug("fuse: freeing memory range start_idx=0x%lx end_idx=0x%lx window_offset=0x%llx length=0x%llx\n",
295 dmap->itn.start, dmap->itn.last, dmap->window_offset,
296 dmap->length);
297 __dmap_remove_busy_list(fcd, dmap);
298 dmap->inode = NULL;
299 dmap->itn.start = dmap->itn.last = 0;
300 __dmap_add_to_free_pool(fcd, dmap);
301}
302
303/*
304 * Free inode dmap entries whose range falls inside [start, end].
305 * Does not take any locks. At this point of time it should only be
306 * called from evict_inode() path where we know all dmap entries can be
307 * reclaimed.
308 */
309static void inode_reclaim_dmap_range(struct fuse_conn_dax *fcd,
310 struct inode *inode,
311 loff_t start, loff_t end)
312{
313 struct fuse_inode *fi = get_fuse_inode(inode);
314 struct fuse_dax_mapping *dmap, *n;
315 int err, num = 0;
316 LIST_HEAD(to_remove);
317 unsigned long start_idx = start >> FUSE_DAX_SHIFT;
318 unsigned long end_idx = end >> FUSE_DAX_SHIFT;
319 struct interval_tree_node *node;
320
321 while (1) {
322 node = interval_tree_iter_first(&fi->dax->tree, start_idx,
323 end_idx);
324 if (!node)
325 break;
326 dmap = node_to_dmap(node);
327 /* inode is going away. There should not be any users of dmap */
328 WARN_ON(refcount_read(&dmap->refcnt) > 1);
329 interval_tree_remove(&dmap->itn, &fi->dax->tree);
330 num++;
331 list_add(&dmap->list, &to_remove);
332 }
333
334 /* Nothing to remove */
335 if (list_empty(&to_remove))
336 return;
337
338 WARN_ON(fi->dax->nr < num);
339 fi->dax->nr -= num;
340 err = dmap_removemapping_list(inode, num, &to_remove);
341 if (err && err != -ENOTCONN) {
342 pr_warn("Failed to removemappings. start=0x%llx end=0x%llx\n",
343 start, end);
344 }
345 spin_lock(&fcd->lock);
346 list_for_each_entry_safe(dmap, n, &to_remove, list) {
347 list_del_init(&dmap->list);
348 dmap_reinit_add_to_free_pool(fcd, dmap);
349 }
350 spin_unlock(&fcd->lock);
351}
352
353static int dmap_removemapping_one(struct inode *inode,
354 struct fuse_dax_mapping *dmap)
355{
356 struct fuse_removemapping_one forget_one;
357 struct fuse_removemapping_in inarg;
358
359 memset(&inarg, 0, sizeof(inarg));
360 inarg.count = 1;
361 memset(&forget_one, 0, sizeof(forget_one));
362 forget_one.moffset = dmap->window_offset;
363 forget_one.len = dmap->length;
364
365 return fuse_send_removemapping(inode, &inarg, &forget_one);
366}
367
368/*
369 * It is called from evict_inode() and by that time inode is going away. So
370 * this function does not take any locks like fi->dax->sem for traversing
371 * that fuse inode interval tree. If that lock is taken then lock validator
372 * complains of deadlock situation w.r.t fs_reclaim lock.
373 */
374void fuse_dax_inode_cleanup(struct inode *inode)
375{
376 struct fuse_conn *fc = get_fuse_conn(inode);
377 struct fuse_inode *fi = get_fuse_inode(inode);
378
379 /*
380 * fuse_evict_inode() has already called truncate_inode_pages_final()
381 * before we arrive here. So we should not have to worry about any
382 * pages/exception entries still associated with inode.
383 */
384 inode_reclaim_dmap_range(fc->dax, inode, 0, -1);
385 WARN_ON(fi->dax->nr);
386}
387
388static void fuse_fill_iomap_hole(struct iomap *iomap, loff_t length)
389{
390 iomap->addr = IOMAP_NULL_ADDR;
391 iomap->length = length;
392 iomap->type = IOMAP_HOLE;
393}
394
395static void fuse_fill_iomap(struct inode *inode, loff_t pos, loff_t length,
396 struct iomap *iomap, struct fuse_dax_mapping *dmap,
397 unsigned int flags)
398{
399 loff_t offset, len;
400 loff_t i_size = i_size_read(inode);
401
402 offset = pos - (dmap->itn.start << FUSE_DAX_SHIFT);
403 len = min(length, dmap->length - offset);
404
405 /* If length is beyond end of file, truncate further */
406 if (pos + len > i_size)
407 len = i_size - pos;
408
409 if (len > 0) {
410 iomap->addr = dmap->window_offset + offset;
411 iomap->length = len;
412 if (flags & IOMAP_FAULT)
413 iomap->length = ALIGN(len, PAGE_SIZE);
414 iomap->type = IOMAP_MAPPED;
415 /*
416 * increace refcnt so that reclaim code knows this dmap is in
417 * use. This assumes fi->dax->sem mutex is held either
418 * shared/exclusive.
419 */
420 refcount_inc(&dmap->refcnt);
421
422 /* iomap->private should be NULL */
423 WARN_ON_ONCE(iomap->private);
424 iomap->private = dmap;
425 } else {
426 /* Mapping beyond end of file is hole */
427 fuse_fill_iomap_hole(iomap, length);
428 }
429}
430
431static int fuse_setup_new_dax_mapping(struct inode *inode, loff_t pos,
432 loff_t length, unsigned int flags,
433 struct iomap *iomap)
434{
435 struct fuse_inode *fi = get_fuse_inode(inode);
436 struct fuse_conn *fc = get_fuse_conn(inode);
437 struct fuse_conn_dax *fcd = fc->dax;
438 struct fuse_dax_mapping *dmap, *alloc_dmap = NULL;
439 int ret;
440 bool writable = flags & IOMAP_WRITE;
441 unsigned long start_idx = pos >> FUSE_DAX_SHIFT;
442 struct interval_tree_node *node;
443
444 /*
445 * Can't do inline reclaim in fault path. We call
446 * dax_layout_busy_page() before we free a range. And
447 * fuse_wait_dax_page() drops mapping->invalidate_lock and requires it.
448 * In fault path we enter with mapping->invalidate_lock held and can't
449 * drop it. Also in fault path we hold mapping->invalidate_lock shared
450 * and not exclusive, so that creates further issues with
451 * fuse_wait_dax_page(). Hence return -EAGAIN and fuse_dax_fault()
452 * will wait for a memory range to become free and retry.
453 */
454 if (flags & IOMAP_FAULT) {
455 alloc_dmap = alloc_dax_mapping(fcd);
456 if (!alloc_dmap)
457 return -EAGAIN;
458 } else {
459 alloc_dmap = alloc_dax_mapping_reclaim(fcd, inode);
460 if (IS_ERR(alloc_dmap))
461 return PTR_ERR(alloc_dmap);
462 }
463
464 /* If we are here, we should have memory allocated */
465 if (WARN_ON(!alloc_dmap))
466 return -EIO;
467
468 /*
469 * Take write lock so that only one caller can try to setup mapping
470 * and other waits.
471 */
472 down_write(&fi->dax->sem);
473 /*
474 * We dropped lock. Check again if somebody else setup
475 * mapping already.
476 */
477 node = interval_tree_iter_first(&fi->dax->tree, start_idx, start_idx);
478 if (node) {
479 dmap = node_to_dmap(node);
480 fuse_fill_iomap(inode, pos, length, iomap, dmap, flags);
481 dmap_add_to_free_pool(fcd, alloc_dmap);
482 up_write(&fi->dax->sem);
483 return 0;
484 }
485
486 /* Setup one mapping */
487 ret = fuse_setup_one_mapping(inode, pos >> FUSE_DAX_SHIFT, alloc_dmap,
488 writable, false);
489 if (ret < 0) {
490 dmap_add_to_free_pool(fcd, alloc_dmap);
491 up_write(&fi->dax->sem);
492 return ret;
493 }
494 fuse_fill_iomap(inode, pos, length, iomap, alloc_dmap, flags);
495 up_write(&fi->dax->sem);
496 return 0;
497}
498
499static int fuse_upgrade_dax_mapping(struct inode *inode, loff_t pos,
500 loff_t length, unsigned int flags,
501 struct iomap *iomap)
502{
503 struct fuse_inode *fi = get_fuse_inode(inode);
504 struct fuse_dax_mapping *dmap;
505 int ret;
506 unsigned long idx = pos >> FUSE_DAX_SHIFT;
507 struct interval_tree_node *node;
508
509 /*
510 * Take exclusive lock so that only one caller can try to setup
511 * mapping and others wait.
512 */
513 down_write(&fi->dax->sem);
514 node = interval_tree_iter_first(&fi->dax->tree, idx, idx);
515
516 /* We are holding either inode lock or invalidate_lock, and that should
517 * ensure that dmap can't be truncated. We are holding a reference
518 * on dmap and that should make sure it can't be reclaimed. So dmap
519 * should still be there in tree despite the fact we dropped and
520 * re-acquired the fi->dax->sem lock.
521 */
522 ret = -EIO;
523 if (WARN_ON(!node))
524 goto out_err;
525
526 dmap = node_to_dmap(node);
527
528 /* We took an extra reference on dmap to make sure its not reclaimd.
529 * Now we hold fi->dax->sem lock and that reference is not needed
530 * anymore. Drop it.
531 */
532 if (refcount_dec_and_test(&dmap->refcnt)) {
533 /* refcount should not hit 0. This object only goes
534 * away when fuse connection goes away
535 */
536 WARN_ON_ONCE(1);
537 }
538
539 /* Maybe another thread already upgraded mapping while we were not
540 * holding lock.
541 */
542 if (dmap->writable) {
543 ret = 0;
544 goto out_fill_iomap;
545 }
546
547 ret = fuse_setup_one_mapping(inode, pos >> FUSE_DAX_SHIFT, dmap, true,
548 true);
549 if (ret < 0)
550 goto out_err;
551out_fill_iomap:
552 fuse_fill_iomap(inode, pos, length, iomap, dmap, flags);
553out_err:
554 up_write(&fi->dax->sem);
555 return ret;
556}
557
558/* This is just for DAX and the mapping is ephemeral, do not use it for other
559 * purposes since there is no block device with a permanent mapping.
560 */
561static int fuse_iomap_begin(struct inode *inode, loff_t pos, loff_t length,
562 unsigned int flags, struct iomap *iomap,
563 struct iomap *srcmap)
564{
565 struct fuse_inode *fi = get_fuse_inode(inode);
566 struct fuse_conn *fc = get_fuse_conn(inode);
567 struct fuse_dax_mapping *dmap;
568 bool writable = flags & IOMAP_WRITE;
569 unsigned long start_idx = pos >> FUSE_DAX_SHIFT;
570 struct interval_tree_node *node;
571
572 /* We don't support FIEMAP */
573 if (WARN_ON(flags & IOMAP_REPORT))
574 return -EIO;
575
576 iomap->offset = pos;
577 iomap->flags = 0;
578 iomap->bdev = NULL;
579 iomap->dax_dev = fc->dax->dev;
580
581 /*
582 * Both read/write and mmap path can race here. So we need something
583 * to make sure if we are setting up mapping, then other path waits
584 *
585 * For now, use a semaphore for this. It probably needs to be
586 * optimized later.
587 */
588 down_read(&fi->dax->sem);
589 node = interval_tree_iter_first(&fi->dax->tree, start_idx, start_idx);
590 if (node) {
591 dmap = node_to_dmap(node);
592 if (writable && !dmap->writable) {
593 /* Upgrade read-only mapping to read-write. This will
594 * require exclusive fi->dax->sem lock as we don't want
595 * two threads to be trying to this simultaneously
596 * for same dmap. So drop shared lock and acquire
597 * exclusive lock.
598 *
599 * Before dropping fi->dax->sem lock, take reference
600 * on dmap so that its not freed by range reclaim.
601 */
602 refcount_inc(&dmap->refcnt);
603 up_read(&fi->dax->sem);
604 pr_debug("%s: Upgrading mapping at offset 0x%llx length 0x%llx\n",
605 __func__, pos, length);
606 return fuse_upgrade_dax_mapping(inode, pos, length,
607 flags, iomap);
608 } else {
609 fuse_fill_iomap(inode, pos, length, iomap, dmap, flags);
610 up_read(&fi->dax->sem);
611 return 0;
612 }
613 } else {
614 up_read(&fi->dax->sem);
615 pr_debug("%s: no mapping at offset 0x%llx length 0x%llx\n",
616 __func__, pos, length);
617 if (pos >= i_size_read(inode))
618 goto iomap_hole;
619
620 return fuse_setup_new_dax_mapping(inode, pos, length, flags,
621 iomap);
622 }
623
624 /*
625 * If read beyond end of file happens, fs code seems to return
626 * it as hole
627 */
628iomap_hole:
629 fuse_fill_iomap_hole(iomap, length);
630 pr_debug("%s returning hole mapping. pos=0x%llx length_asked=0x%llx length_returned=0x%llx\n",
631 __func__, pos, length, iomap->length);
632 return 0;
633}
634
635static int fuse_iomap_end(struct inode *inode, loff_t pos, loff_t length,
636 ssize_t written, unsigned int flags,
637 struct iomap *iomap)
638{
639 struct fuse_dax_mapping *dmap = iomap->private;
640
641 if (dmap) {
642 if (refcount_dec_and_test(&dmap->refcnt)) {
643 /* refcount should not hit 0. This object only goes
644 * away when fuse connection goes away
645 */
646 WARN_ON_ONCE(1);
647 }
648 }
649
650 /* DAX writes beyond end-of-file aren't handled using iomap, so the
651 * file size is unchanged and there is nothing to do here.
652 */
653 return 0;
654}
655
656static const struct iomap_ops fuse_iomap_ops = {
657 .iomap_begin = fuse_iomap_begin,
658 .iomap_end = fuse_iomap_end,
659};
660
661static void fuse_wait_dax_page(struct inode *inode)
662{
663 filemap_invalidate_unlock(inode->i_mapping);
664 schedule();
665 filemap_invalidate_lock(inode->i_mapping);
666}
667
668/* Should be called with mapping->invalidate_lock held exclusively */
669static int __fuse_dax_break_layouts(struct inode *inode, bool *retry,
670 loff_t start, loff_t end)
671{
672 struct page *page;
673
674 page = dax_layout_busy_page_range(inode->i_mapping, start, end);
675 if (!page)
676 return 0;
677
678 *retry = true;
679 return ___wait_var_event(&page->_refcount,
680 atomic_read(&page->_refcount) == 1, TASK_INTERRUPTIBLE,
681 0, 0, fuse_wait_dax_page(inode));
682}
683
684/* dmap_end == 0 leads to unmapping of whole file */
685int fuse_dax_break_layouts(struct inode *inode, u64 dmap_start,
686 u64 dmap_end)
687{
688 bool retry;
689 int ret;
690
691 do {
692 retry = false;
693 ret = __fuse_dax_break_layouts(inode, &retry, dmap_start,
694 dmap_end);
695 } while (ret == 0 && retry);
696
697 return ret;
698}
699
700ssize_t fuse_dax_read_iter(struct kiocb *iocb, struct iov_iter *to)
701{
702 struct inode *inode = file_inode(iocb->ki_filp);
703 ssize_t ret;
704
705 if (iocb->ki_flags & IOCB_NOWAIT) {
706 if (!inode_trylock_shared(inode))
707 return -EAGAIN;
708 } else {
709 inode_lock_shared(inode);
710 }
711
712 ret = dax_iomap_rw(iocb, to, &fuse_iomap_ops);
713 inode_unlock_shared(inode);
714
715 /* TODO file_accessed(iocb->f_filp) */
716 return ret;
717}
718
719static bool file_extending_write(struct kiocb *iocb, struct iov_iter *from)
720{
721 struct inode *inode = file_inode(iocb->ki_filp);
722
723 return (iov_iter_rw(from) == WRITE &&
724 ((iocb->ki_pos) >= i_size_read(inode) ||
725 (iocb->ki_pos + iov_iter_count(from) > i_size_read(inode))));
726}
727
728static ssize_t fuse_dax_direct_write(struct kiocb *iocb, struct iov_iter *from)
729{
730 struct inode *inode = file_inode(iocb->ki_filp);
731 struct fuse_io_priv io = FUSE_IO_PRIV_SYNC(iocb);
732 ssize_t ret;
733
734 ret = fuse_direct_io(&io, from, &iocb->ki_pos, FUSE_DIO_WRITE);
735
736 fuse_write_update_attr(inode, iocb->ki_pos, ret);
737 return ret;
738}
739
740ssize_t fuse_dax_write_iter(struct kiocb *iocb, struct iov_iter *from)
741{
742 struct inode *inode = file_inode(iocb->ki_filp);
743 ssize_t ret;
744
745 if (iocb->ki_flags & IOCB_NOWAIT) {
746 if (!inode_trylock(inode))
747 return -EAGAIN;
748 } else {
749 inode_lock(inode);
750 }
751
752 ret = generic_write_checks(iocb, from);
753 if (ret <= 0)
754 goto out;
755
756 ret = file_remove_privs(iocb->ki_filp);
757 if (ret)
758 goto out;
759 /* TODO file_update_time() but we don't want metadata I/O */
760
761 /* Do not use dax for file extending writes as write and on
762 * disk i_size increase are not atomic otherwise.
763 */
764 if (file_extending_write(iocb, from))
765 ret = fuse_dax_direct_write(iocb, from);
766 else
767 ret = dax_iomap_rw(iocb, from, &fuse_iomap_ops);
768
769out:
770 inode_unlock(inode);
771
772 if (ret > 0)
773 ret = generic_write_sync(iocb, ret);
774 return ret;
775}
776
777static int fuse_dax_writepages(struct address_space *mapping,
778 struct writeback_control *wbc)
779{
780
781 struct inode *inode = mapping->host;
782 struct fuse_conn *fc = get_fuse_conn(inode);
783
784 return dax_writeback_mapping_range(mapping, fc->dax->dev, wbc);
785}
786
787static vm_fault_t __fuse_dax_fault(struct vm_fault *vmf,
788 enum page_entry_size pe_size, bool write)
789{
790 vm_fault_t ret;
791 struct inode *inode = file_inode(vmf->vma->vm_file);
792 struct super_block *sb = inode->i_sb;
793 pfn_t pfn;
794 int error = 0;
795 struct fuse_conn *fc = get_fuse_conn(inode);
796 struct fuse_conn_dax *fcd = fc->dax;
797 bool retry = false;
798
799 if (write)
800 sb_start_pagefault(sb);
801retry:
802 if (retry && !(fcd->nr_free_ranges > 0))
803 wait_event(fcd->range_waitq, (fcd->nr_free_ranges > 0));
804
805 /*
806 * We need to serialize against not only truncate but also against
807 * fuse dax memory range reclaim. While a range is being reclaimed,
808 * we do not want any read/write/mmap to make progress and try
809 * to populate page cache or access memory we are trying to free.
810 */
811 filemap_invalidate_lock_shared(inode->i_mapping);
812 ret = dax_iomap_fault(vmf, pe_size, &pfn, &error, &fuse_iomap_ops);
813 if ((ret & VM_FAULT_ERROR) && error == -EAGAIN) {
814 error = 0;
815 retry = true;
816 filemap_invalidate_unlock_shared(inode->i_mapping);
817 goto retry;
818 }
819
820 if (ret & VM_FAULT_NEEDDSYNC)
821 ret = dax_finish_sync_fault(vmf, pe_size, pfn);
822 filemap_invalidate_unlock_shared(inode->i_mapping);
823
824 if (write)
825 sb_end_pagefault(sb);
826
827 return ret;
828}
829
830static vm_fault_t fuse_dax_fault(struct vm_fault *vmf)
831{
832 return __fuse_dax_fault(vmf, PE_SIZE_PTE,
833 vmf->flags & FAULT_FLAG_WRITE);
834}
835
836static vm_fault_t fuse_dax_huge_fault(struct vm_fault *vmf,
837 enum page_entry_size pe_size)
838{
839 return __fuse_dax_fault(vmf, pe_size, vmf->flags & FAULT_FLAG_WRITE);
840}
841
842static vm_fault_t fuse_dax_page_mkwrite(struct vm_fault *vmf)
843{
844 return __fuse_dax_fault(vmf, PE_SIZE_PTE, true);
845}
846
847static vm_fault_t fuse_dax_pfn_mkwrite(struct vm_fault *vmf)
848{
849 return __fuse_dax_fault(vmf, PE_SIZE_PTE, true);
850}
851
852static const struct vm_operations_struct fuse_dax_vm_ops = {
853 .fault = fuse_dax_fault,
854 .huge_fault = fuse_dax_huge_fault,
855 .page_mkwrite = fuse_dax_page_mkwrite,
856 .pfn_mkwrite = fuse_dax_pfn_mkwrite,
857};
858
859int fuse_dax_mmap(struct file *file, struct vm_area_struct *vma)
860{
861 file_accessed(file);
862 vma->vm_ops = &fuse_dax_vm_ops;
863 vma->vm_flags |= VM_MIXEDMAP | VM_HUGEPAGE;
864 return 0;
865}
866
867static int dmap_writeback_invalidate(struct inode *inode,
868 struct fuse_dax_mapping *dmap)
869{
870 int ret;
871 loff_t start_pos = dmap->itn.start << FUSE_DAX_SHIFT;
872 loff_t end_pos = (start_pos + FUSE_DAX_SZ - 1);
873
874 ret = filemap_fdatawrite_range(inode->i_mapping, start_pos, end_pos);
875 if (ret) {
876 pr_debug("fuse: filemap_fdatawrite_range() failed. err=%d start_pos=0x%llx, end_pos=0x%llx\n",
877 ret, start_pos, end_pos);
878 return ret;
879 }
880
881 ret = invalidate_inode_pages2_range(inode->i_mapping,
882 start_pos >> PAGE_SHIFT,
883 end_pos >> PAGE_SHIFT);
884 if (ret)
885 pr_debug("fuse: invalidate_inode_pages2_range() failed err=%d\n",
886 ret);
887
888 return ret;
889}
890
891static int reclaim_one_dmap_locked(struct inode *inode,
892 struct fuse_dax_mapping *dmap)
893{
894 int ret;
895 struct fuse_inode *fi = get_fuse_inode(inode);
896
897 /*
898 * igrab() was done to make sure inode won't go under us, and this
899 * further avoids the race with evict().
900 */
901 ret = dmap_writeback_invalidate(inode, dmap);
902 if (ret)
903 return ret;
904
905 /* Remove dax mapping from inode interval tree now */
906 interval_tree_remove(&dmap->itn, &fi->dax->tree);
907 fi->dax->nr--;
908
909 /* It is possible that umount/shutdown has killed the fuse connection
910 * and worker thread is trying to reclaim memory in parallel. Don't
911 * warn in that case.
912 */
913 ret = dmap_removemapping_one(inode, dmap);
914 if (ret && ret != -ENOTCONN) {
915 pr_warn("Failed to remove mapping. offset=0x%llx len=0x%llx ret=%d\n",
916 dmap->window_offset, dmap->length, ret);
917 }
918 return 0;
919}
920
921/* Find first mapped dmap for an inode and return file offset. Caller needs
922 * to hold fi->dax->sem lock either shared or exclusive.
923 */
924static struct fuse_dax_mapping *inode_lookup_first_dmap(struct inode *inode)
925{
926 struct fuse_inode *fi = get_fuse_inode(inode);
927 struct fuse_dax_mapping *dmap;
928 struct interval_tree_node *node;
929
930 for (node = interval_tree_iter_first(&fi->dax->tree, 0, -1); node;
931 node = interval_tree_iter_next(node, 0, -1)) {
932 dmap = node_to_dmap(node);
933 /* still in use. */
934 if (refcount_read(&dmap->refcnt) > 1)
935 continue;
936
937 return dmap;
938 }
939
940 return NULL;
941}
942
943/*
944 * Find first mapping in the tree and free it and return it. Do not add
945 * it back to free pool.
946 */
947static struct fuse_dax_mapping *
948inode_inline_reclaim_one_dmap(struct fuse_conn_dax *fcd, struct inode *inode,
949 bool *retry)
950{
951 struct fuse_inode *fi = get_fuse_inode(inode);
952 struct fuse_dax_mapping *dmap;
953 u64 dmap_start, dmap_end;
954 unsigned long start_idx;
955 int ret;
956 struct interval_tree_node *node;
957
958 filemap_invalidate_lock(inode->i_mapping);
959
960 /* Lookup a dmap and corresponding file offset to reclaim. */
961 down_read(&fi->dax->sem);
962 dmap = inode_lookup_first_dmap(inode);
963 if (dmap) {
964 start_idx = dmap->itn.start;
965 dmap_start = start_idx << FUSE_DAX_SHIFT;
966 dmap_end = dmap_start + FUSE_DAX_SZ - 1;
967 }
968 up_read(&fi->dax->sem);
969
970 if (!dmap)
971 goto out_mmap_sem;
972 /*
973 * Make sure there are no references to inode pages using
974 * get_user_pages()
975 */
976 ret = fuse_dax_break_layouts(inode, dmap_start, dmap_end);
977 if (ret) {
978 pr_debug("fuse: fuse_dax_break_layouts() failed. err=%d\n",
979 ret);
980 dmap = ERR_PTR(ret);
981 goto out_mmap_sem;
982 }
983
984 down_write(&fi->dax->sem);
985 node = interval_tree_iter_first(&fi->dax->tree, start_idx, start_idx);
986 /* Range already got reclaimed by somebody else */
987 if (!node) {
988 if (retry)
989 *retry = true;
990 goto out_write_dmap_sem;
991 }
992
993 dmap = node_to_dmap(node);
994 /* still in use. */
995 if (refcount_read(&dmap->refcnt) > 1) {
996 dmap = NULL;
997 if (retry)
998 *retry = true;
999 goto out_write_dmap_sem;
1000 }
1001
1002 ret = reclaim_one_dmap_locked(inode, dmap);
1003 if (ret < 0) {
1004 dmap = ERR_PTR(ret);
1005 goto out_write_dmap_sem;
1006 }
1007
1008 /* Clean up dmap. Do not add back to free list */
1009 dmap_remove_busy_list(fcd, dmap);
1010 dmap->inode = NULL;
1011 dmap->itn.start = dmap->itn.last = 0;
1012
1013 pr_debug("fuse: %s: inline reclaimed memory range. inode=%p, window_offset=0x%llx, length=0x%llx\n",
1014 __func__, inode, dmap->window_offset, dmap->length);
1015
1016out_write_dmap_sem:
1017 up_write(&fi->dax->sem);
1018out_mmap_sem:
1019 filemap_invalidate_unlock(inode->i_mapping);
1020 return dmap;
1021}
1022
1023static struct fuse_dax_mapping *
1024alloc_dax_mapping_reclaim(struct fuse_conn_dax *fcd, struct inode *inode)
1025{
1026 struct fuse_dax_mapping *dmap;
1027 struct fuse_inode *fi = get_fuse_inode(inode);
1028
1029 while (1) {
1030 bool retry = false;
1031
1032 dmap = alloc_dax_mapping(fcd);
1033 if (dmap)
1034 return dmap;
1035
1036 dmap = inode_inline_reclaim_one_dmap(fcd, inode, &retry);
1037 /*
1038 * Either we got a mapping or it is an error, return in both
1039 * the cases.
1040 */
1041 if (dmap)
1042 return dmap;
1043
1044 /* If we could not reclaim a mapping because it
1045 * had a reference or some other temporary failure,
1046 * Try again. We want to give up inline reclaim only
1047 * if there is no range assigned to this node. Otherwise
1048 * if a deadlock is possible if we sleep with
1049 * mapping->invalidate_lock held and worker to free memory
1050 * can't make progress due to unavailability of
1051 * mapping->invalidate_lock. So sleep only if fi->dax->nr=0
1052 */
1053 if (retry)
1054 continue;
1055 /*
1056 * There are no mappings which can be reclaimed. Wait for one.
1057 * We are not holding fi->dax->sem. So it is possible
1058 * that range gets added now. But as we are not holding
1059 * mapping->invalidate_lock, worker should still be able to
1060 * free up a range and wake us up.
1061 */
1062 if (!fi->dax->nr && !(fcd->nr_free_ranges > 0)) {
1063 if (wait_event_killable_exclusive(fcd->range_waitq,
1064 (fcd->nr_free_ranges > 0))) {
1065 return ERR_PTR(-EINTR);
1066 }
1067 }
1068 }
1069}
1070
1071static int lookup_and_reclaim_dmap_locked(struct fuse_conn_dax *fcd,
1072 struct inode *inode,
1073 unsigned long start_idx)
1074{
1075 int ret;
1076 struct fuse_inode *fi = get_fuse_inode(inode);
1077 struct fuse_dax_mapping *dmap;
1078 struct interval_tree_node *node;
1079
1080 /* Find fuse dax mapping at file offset inode. */
1081 node = interval_tree_iter_first(&fi->dax->tree, start_idx, start_idx);
1082
1083 /* Range already got cleaned up by somebody else */
1084 if (!node)
1085 return 0;
1086 dmap = node_to_dmap(node);
1087
1088 /* still in use. */
1089 if (refcount_read(&dmap->refcnt) > 1)
1090 return 0;
1091
1092 ret = reclaim_one_dmap_locked(inode, dmap);
1093 if (ret < 0)
1094 return ret;
1095
1096 /* Cleanup dmap entry and add back to free list */
1097 spin_lock(&fcd->lock);
1098 dmap_reinit_add_to_free_pool(fcd, dmap);
1099 spin_unlock(&fcd->lock);
1100 return ret;
1101}
1102
1103/*
1104 * Free a range of memory.
1105 * Locking:
1106 * 1. Take mapping->invalidate_lock to block dax faults.
1107 * 2. Take fi->dax->sem to protect interval tree and also to make sure
1108 * read/write can not reuse a dmap which we might be freeing.
1109 */
1110static int lookup_and_reclaim_dmap(struct fuse_conn_dax *fcd,
1111 struct inode *inode,
1112 unsigned long start_idx,
1113 unsigned long end_idx)
1114{
1115 int ret;
1116 struct fuse_inode *fi = get_fuse_inode(inode);
1117 loff_t dmap_start = start_idx << FUSE_DAX_SHIFT;
1118 loff_t dmap_end = (dmap_start + FUSE_DAX_SZ) - 1;
1119
1120 filemap_invalidate_lock(inode->i_mapping);
1121 ret = fuse_dax_break_layouts(inode, dmap_start, dmap_end);
1122 if (ret) {
1123 pr_debug("virtio_fs: fuse_dax_break_layouts() failed. err=%d\n",
1124 ret);
1125 goto out_mmap_sem;
1126 }
1127
1128 down_write(&fi->dax->sem);
1129 ret = lookup_and_reclaim_dmap_locked(fcd, inode, start_idx);
1130 up_write(&fi->dax->sem);
1131out_mmap_sem:
1132 filemap_invalidate_unlock(inode->i_mapping);
1133 return ret;
1134}
1135
1136static int try_to_free_dmap_chunks(struct fuse_conn_dax *fcd,
1137 unsigned long nr_to_free)
1138{
1139 struct fuse_dax_mapping *dmap, *pos, *temp;
1140 int ret, nr_freed = 0;
1141 unsigned long start_idx = 0, end_idx = 0;
1142 struct inode *inode = NULL;
1143
1144 /* Pick first busy range and free it for now*/
1145 while (1) {
1146 if (nr_freed >= nr_to_free)
1147 break;
1148
1149 dmap = NULL;
1150 spin_lock(&fcd->lock);
1151
1152 if (!fcd->nr_busy_ranges) {
1153 spin_unlock(&fcd->lock);
1154 return 0;
1155 }
1156
1157 list_for_each_entry_safe(pos, temp, &fcd->busy_ranges,
1158 busy_list) {
1159 /* skip this range if it's in use. */
1160 if (refcount_read(&pos->refcnt) > 1)
1161 continue;
1162
1163 inode = igrab(pos->inode);
1164 /*
1165 * This inode is going away. That will free
1166 * up all the ranges anyway, continue to
1167 * next range.
1168 */
1169 if (!inode)
1170 continue;
1171 /*
1172 * Take this element off list and add it tail. If
1173 * this element can't be freed, it will help with
1174 * selecting new element in next iteration of loop.
1175 */
1176 dmap = pos;
1177 list_move_tail(&dmap->busy_list, &fcd->busy_ranges);
1178 start_idx = end_idx = dmap->itn.start;
1179 break;
1180 }
1181 spin_unlock(&fcd->lock);
1182 if (!dmap)
1183 return 0;
1184
1185 ret = lookup_and_reclaim_dmap(fcd, inode, start_idx, end_idx);
1186 iput(inode);
1187 if (ret)
1188 return ret;
1189 nr_freed++;
1190 }
1191 return 0;
1192}
1193
1194static void fuse_dax_free_mem_worker(struct work_struct *work)
1195{
1196 int ret;
1197 struct fuse_conn_dax *fcd = container_of(work, struct fuse_conn_dax,
1198 free_work.work);
1199 ret = try_to_free_dmap_chunks(fcd, FUSE_DAX_RECLAIM_CHUNK);
1200 if (ret) {
1201 pr_debug("fuse: try_to_free_dmap_chunks() failed with err=%d\n",
1202 ret);
1203 }
1204
1205 /* If number of free ranges are still below threshold, requeue */
1206 kick_dmap_free_worker(fcd, 1);
1207}
1208
1209static void fuse_free_dax_mem_ranges(struct list_head *mem_list)
1210{
1211 struct fuse_dax_mapping *range, *temp;
1212
1213 /* Free All allocated elements */
1214 list_for_each_entry_safe(range, temp, mem_list, list) {
1215 list_del(&range->list);
1216 if (!list_empty(&range->busy_list))
1217 list_del(&range->busy_list);
1218 kfree(range);
1219 }
1220}
1221
1222void fuse_dax_conn_free(struct fuse_conn *fc)
1223{
1224 if (fc->dax) {
1225 fuse_free_dax_mem_ranges(&fc->dax->free_ranges);
1226 kfree(fc->dax);
1227 }
1228}
1229
1230static int fuse_dax_mem_range_init(struct fuse_conn_dax *fcd)
1231{
1232 long nr_pages, nr_ranges;
1233 struct fuse_dax_mapping *range;
1234 int ret, id;
1235 size_t dax_size = -1;
1236 unsigned long i;
1237
1238 init_waitqueue_head(&fcd->range_waitq);
1239 INIT_LIST_HEAD(&fcd->free_ranges);
1240 INIT_LIST_HEAD(&fcd->busy_ranges);
1241 INIT_DELAYED_WORK(&fcd->free_work, fuse_dax_free_mem_worker);
1242
1243 id = dax_read_lock();
1244 nr_pages = dax_direct_access(fcd->dev, 0, PHYS_PFN(dax_size),
1245 DAX_ACCESS, NULL, NULL);
1246 dax_read_unlock(id);
1247 if (nr_pages < 0) {
1248 pr_debug("dax_direct_access() returned %ld\n", nr_pages);
1249 return nr_pages;
1250 }
1251
1252 nr_ranges = nr_pages/FUSE_DAX_PAGES;
1253 pr_debug("%s: dax mapped %ld pages. nr_ranges=%ld\n",
1254 __func__, nr_pages, nr_ranges);
1255
1256 for (i = 0; i < nr_ranges; i++) {
1257 range = kzalloc(sizeof(struct fuse_dax_mapping), GFP_KERNEL);
1258 ret = -ENOMEM;
1259 if (!range)
1260 goto out_err;
1261
1262 /* TODO: This offset only works if virtio-fs driver is not
1263 * having some memory hidden at the beginning. This needs
1264 * better handling
1265 */
1266 range->window_offset = i * FUSE_DAX_SZ;
1267 range->length = FUSE_DAX_SZ;
1268 INIT_LIST_HEAD(&range->busy_list);
1269 refcount_set(&range->refcnt, 1);
1270 list_add_tail(&range->list, &fcd->free_ranges);
1271 }
1272
1273 fcd->nr_free_ranges = nr_ranges;
1274 fcd->nr_ranges = nr_ranges;
1275 return 0;
1276out_err:
1277 /* Free All allocated elements */
1278 fuse_free_dax_mem_ranges(&fcd->free_ranges);
1279 return ret;
1280}
1281
1282int fuse_dax_conn_alloc(struct fuse_conn *fc, enum fuse_dax_mode dax_mode,
1283 struct dax_device *dax_dev)
1284{
1285 struct fuse_conn_dax *fcd;
1286 int err;
1287
1288 fc->dax_mode = dax_mode;
1289
1290 if (!dax_dev)
1291 return 0;
1292
1293 fcd = kzalloc(sizeof(*fcd), GFP_KERNEL);
1294 if (!fcd)
1295 return -ENOMEM;
1296
1297 spin_lock_init(&fcd->lock);
1298 fcd->dev = dax_dev;
1299 err = fuse_dax_mem_range_init(fcd);
1300 if (err) {
1301 kfree(fcd);
1302 return err;
1303 }
1304
1305 fc->dax = fcd;
1306 return 0;
1307}
1308
1309bool fuse_dax_inode_alloc(struct super_block *sb, struct fuse_inode *fi)
1310{
1311 struct fuse_conn *fc = get_fuse_conn_super(sb);
1312
1313 fi->dax = NULL;
1314 if (fc->dax) {
1315 fi->dax = kzalloc(sizeof(*fi->dax), GFP_KERNEL_ACCOUNT);
1316 if (!fi->dax)
1317 return false;
1318
1319 init_rwsem(&fi->dax->sem);
1320 fi->dax->tree = RB_ROOT_CACHED;
1321 }
1322
1323 return true;
1324}
1325
1326static const struct address_space_operations fuse_dax_file_aops = {
1327 .writepages = fuse_dax_writepages,
1328 .direct_IO = noop_direct_IO,
1329 .dirty_folio = noop_dirty_folio,
1330};
1331
1332static bool fuse_should_enable_dax(struct inode *inode, unsigned int flags)
1333{
1334 struct fuse_conn *fc = get_fuse_conn(inode);
1335 enum fuse_dax_mode dax_mode = fc->dax_mode;
1336
1337 if (dax_mode == FUSE_DAX_NEVER)
1338 return false;
1339
1340 /*
1341 * fc->dax may be NULL in 'inode' mode when filesystem device doesn't
1342 * support DAX, in which case it will silently fallback to 'never' mode.
1343 */
1344 if (!fc->dax)
1345 return false;
1346
1347 if (dax_mode == FUSE_DAX_ALWAYS)
1348 return true;
1349
1350 /* dax_mode is FUSE_DAX_INODE* */
1351 return fc->inode_dax && (flags & FUSE_ATTR_DAX);
1352}
1353
1354void fuse_dax_inode_init(struct inode *inode, unsigned int flags)
1355{
1356 if (!fuse_should_enable_dax(inode, flags))
1357 return;
1358
1359 inode->i_flags |= S_DAX;
1360 inode->i_data.a_ops = &fuse_dax_file_aops;
1361}
1362
1363void fuse_dax_dontcache(struct inode *inode, unsigned int flags)
1364{
1365 struct fuse_conn *fc = get_fuse_conn(inode);
1366
1367 if (fuse_is_inode_dax_mode(fc->dax_mode) &&
1368 ((bool) IS_DAX(inode) != (bool) (flags & FUSE_ATTR_DAX)))
1369 d_mark_dontcache(inode);
1370}
1371
1372bool fuse_dax_check_alignment(struct fuse_conn *fc, unsigned int map_alignment)
1373{
1374 if (fc->dax && (map_alignment > FUSE_DAX_SHIFT)) {
1375 pr_warn("FUSE: map_alignment %u incompatible with dax mem range size %u\n",
1376 map_alignment, FUSE_DAX_SZ);
1377 return false;
1378 }
1379 return true;
1380}
1381
1382void fuse_dax_cancel_work(struct fuse_conn *fc)
1383{
1384 struct fuse_conn_dax *fcd = fc->dax;
1385
1386 if (fcd)
1387 cancel_delayed_work_sync(&fcd->free_work);
1388
1389}
1390EXPORT_SYMBOL_GPL(fuse_dax_cancel_work);