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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Simple file system for zoned block devices exposing zones as files.
4 *
5 * Copyright (C) 2022 Western Digital Corporation or its affiliates.
6 */
7#include <linux/module.h>
8#include <linux/pagemap.h>
9#include <linux/iomap.h>
10#include <linux/init.h>
11#include <linux/slab.h>
12#include <linux/blkdev.h>
13#include <linux/statfs.h>
14#include <linux/writeback.h>
15#include <linux/quotaops.h>
16#include <linux/seq_file.h>
17#include <linux/parser.h>
18#include <linux/uio.h>
19#include <linux/mman.h>
20#include <linux/sched/mm.h>
21#include <linux/task_io_accounting_ops.h>
22
23#include "zonefs.h"
24
25#include "trace.h"
26
27static int zonefs_read_iomap_begin(struct inode *inode, loff_t offset,
28 loff_t length, unsigned int flags,
29 struct iomap *iomap, struct iomap *srcmap)
30{
31 struct zonefs_inode_info *zi = ZONEFS_I(inode);
32 struct zonefs_zone *z = zonefs_inode_zone(inode);
33 struct super_block *sb = inode->i_sb;
34 loff_t isize;
35
36 /*
37 * All blocks are always mapped below EOF. If reading past EOF,
38 * act as if there is a hole up to the file maximum size.
39 */
40 mutex_lock(&zi->i_truncate_mutex);
41 iomap->bdev = inode->i_sb->s_bdev;
42 iomap->offset = ALIGN_DOWN(offset, sb->s_blocksize);
43 isize = i_size_read(inode);
44 if (iomap->offset >= isize) {
45 iomap->type = IOMAP_HOLE;
46 iomap->addr = IOMAP_NULL_ADDR;
47 iomap->length = length;
48 } else {
49 iomap->type = IOMAP_MAPPED;
50 iomap->addr = (z->z_sector << SECTOR_SHIFT) + iomap->offset;
51 iomap->length = isize - iomap->offset;
52 }
53 mutex_unlock(&zi->i_truncate_mutex);
54
55 trace_zonefs_iomap_begin(inode, iomap);
56
57 return 0;
58}
59
60static const struct iomap_ops zonefs_read_iomap_ops = {
61 .iomap_begin = zonefs_read_iomap_begin,
62};
63
64static int zonefs_write_iomap_begin(struct inode *inode, loff_t offset,
65 loff_t length, unsigned int flags,
66 struct iomap *iomap, struct iomap *srcmap)
67{
68 struct zonefs_inode_info *zi = ZONEFS_I(inode);
69 struct zonefs_zone *z = zonefs_inode_zone(inode);
70 struct super_block *sb = inode->i_sb;
71 loff_t isize;
72
73 /* All write I/Os should always be within the file maximum size */
74 if (WARN_ON_ONCE(offset + length > z->z_capacity))
75 return -EIO;
76
77 /*
78 * Sequential zones can only accept direct writes. This is already
79 * checked when writes are issued, so warn if we see a page writeback
80 * operation.
81 */
82 if (WARN_ON_ONCE(zonefs_zone_is_seq(z) && !(flags & IOMAP_DIRECT)))
83 return -EIO;
84
85 /*
86 * For conventional zones, all blocks are always mapped. For sequential
87 * zones, all blocks after always mapped below the inode size (zone
88 * write pointer) and unwriten beyond.
89 */
90 mutex_lock(&zi->i_truncate_mutex);
91 iomap->bdev = inode->i_sb->s_bdev;
92 iomap->offset = ALIGN_DOWN(offset, sb->s_blocksize);
93 iomap->addr = (z->z_sector << SECTOR_SHIFT) + iomap->offset;
94 isize = i_size_read(inode);
95 if (iomap->offset >= isize) {
96 iomap->type = IOMAP_UNWRITTEN;
97 iomap->length = z->z_capacity - iomap->offset;
98 } else {
99 iomap->type = IOMAP_MAPPED;
100 iomap->length = isize - iomap->offset;
101 }
102 mutex_unlock(&zi->i_truncate_mutex);
103
104 trace_zonefs_iomap_begin(inode, iomap);
105
106 return 0;
107}
108
109static const struct iomap_ops zonefs_write_iomap_ops = {
110 .iomap_begin = zonefs_write_iomap_begin,
111};
112
113static int zonefs_read_folio(struct file *unused, struct folio *folio)
114{
115 return iomap_read_folio(folio, &zonefs_read_iomap_ops);
116}
117
118static void zonefs_readahead(struct readahead_control *rac)
119{
120 iomap_readahead(rac, &zonefs_read_iomap_ops);
121}
122
123/*
124 * Map blocks for page writeback. This is used only on conventional zone files,
125 * which implies that the page range can only be within the fixed inode size.
126 */
127static int zonefs_write_map_blocks(struct iomap_writepage_ctx *wpc,
128 struct inode *inode, loff_t offset)
129{
130 struct zonefs_zone *z = zonefs_inode_zone(inode);
131
132 if (WARN_ON_ONCE(zonefs_zone_is_seq(z)))
133 return -EIO;
134 if (WARN_ON_ONCE(offset >= i_size_read(inode)))
135 return -EIO;
136
137 /* If the mapping is already OK, nothing needs to be done */
138 if (offset >= wpc->iomap.offset &&
139 offset < wpc->iomap.offset + wpc->iomap.length)
140 return 0;
141
142 return zonefs_write_iomap_begin(inode, offset,
143 z->z_capacity - offset,
144 IOMAP_WRITE, &wpc->iomap, NULL);
145}
146
147static const struct iomap_writeback_ops zonefs_writeback_ops = {
148 .map_blocks = zonefs_write_map_blocks,
149};
150
151static int zonefs_writepages(struct address_space *mapping,
152 struct writeback_control *wbc)
153{
154 struct iomap_writepage_ctx wpc = { };
155
156 return iomap_writepages(mapping, wbc, &wpc, &zonefs_writeback_ops);
157}
158
159static int zonefs_swap_activate(struct swap_info_struct *sis,
160 struct file *swap_file, sector_t *span)
161{
162 struct inode *inode = file_inode(swap_file);
163
164 if (zonefs_inode_is_seq(inode)) {
165 zonefs_err(inode->i_sb,
166 "swap file: not a conventional zone file\n");
167 return -EINVAL;
168 }
169
170 return iomap_swapfile_activate(sis, swap_file, span,
171 &zonefs_read_iomap_ops);
172}
173
174const struct address_space_operations zonefs_file_aops = {
175 .read_folio = zonefs_read_folio,
176 .readahead = zonefs_readahead,
177 .writepages = zonefs_writepages,
178 .dirty_folio = iomap_dirty_folio,
179 .release_folio = iomap_release_folio,
180 .invalidate_folio = iomap_invalidate_folio,
181 .migrate_folio = filemap_migrate_folio,
182 .is_partially_uptodate = iomap_is_partially_uptodate,
183 .error_remove_folio = generic_error_remove_folio,
184 .swap_activate = zonefs_swap_activate,
185};
186
187int zonefs_file_truncate(struct inode *inode, loff_t isize)
188{
189 struct zonefs_inode_info *zi = ZONEFS_I(inode);
190 struct zonefs_zone *z = zonefs_inode_zone(inode);
191 loff_t old_isize;
192 enum req_op op;
193 int ret = 0;
194
195 /*
196 * Only sequential zone files can be truncated and truncation is allowed
197 * only down to a 0 size, which is equivalent to a zone reset, and to
198 * the maximum file size, which is equivalent to a zone finish.
199 */
200 if (!zonefs_zone_is_seq(z))
201 return -EPERM;
202
203 if (!isize)
204 op = REQ_OP_ZONE_RESET;
205 else if (isize == z->z_capacity)
206 op = REQ_OP_ZONE_FINISH;
207 else
208 return -EPERM;
209
210 inode_dio_wait(inode);
211
212 /* Serialize against page faults */
213 filemap_invalidate_lock(inode->i_mapping);
214
215 /* Serialize against zonefs_iomap_begin() */
216 mutex_lock(&zi->i_truncate_mutex);
217
218 old_isize = i_size_read(inode);
219 if (isize == old_isize)
220 goto unlock;
221
222 ret = zonefs_inode_zone_mgmt(inode, op);
223 if (ret)
224 goto unlock;
225
226 /*
227 * If the mount option ZONEFS_MNTOPT_EXPLICIT_OPEN is set,
228 * take care of open zones.
229 */
230 if (z->z_flags & ZONEFS_ZONE_OPEN) {
231 /*
232 * Truncating a zone to EMPTY or FULL is the equivalent of
233 * closing the zone. For a truncation to 0, we need to
234 * re-open the zone to ensure new writes can be processed.
235 * For a truncation to the maximum file size, the zone is
236 * closed and writes cannot be accepted anymore, so clear
237 * the open flag.
238 */
239 if (!isize)
240 ret = zonefs_inode_zone_mgmt(inode, REQ_OP_ZONE_OPEN);
241 else
242 z->z_flags &= ~ZONEFS_ZONE_OPEN;
243 }
244
245 zonefs_update_stats(inode, isize);
246 truncate_setsize(inode, isize);
247 z->z_wpoffset = isize;
248 zonefs_inode_account_active(inode);
249
250unlock:
251 mutex_unlock(&zi->i_truncate_mutex);
252 filemap_invalidate_unlock(inode->i_mapping);
253
254 return ret;
255}
256
257static int zonefs_file_fsync(struct file *file, loff_t start, loff_t end,
258 int datasync)
259{
260 struct inode *inode = file_inode(file);
261 int ret = 0;
262
263 if (unlikely(IS_IMMUTABLE(inode)))
264 return -EPERM;
265
266 /*
267 * Since only direct writes are allowed in sequential files, page cache
268 * flush is needed only for conventional zone files.
269 */
270 if (zonefs_inode_is_cnv(inode))
271 ret = file_write_and_wait_range(file, start, end);
272 if (!ret)
273 ret = blkdev_issue_flush(inode->i_sb->s_bdev);
274
275 if (ret)
276 zonefs_io_error(inode, true);
277
278 return ret;
279}
280
281static vm_fault_t zonefs_filemap_page_mkwrite(struct vm_fault *vmf)
282{
283 struct inode *inode = file_inode(vmf->vma->vm_file);
284 vm_fault_t ret;
285
286 if (unlikely(IS_IMMUTABLE(inode)))
287 return VM_FAULT_SIGBUS;
288
289 /*
290 * Sanity check: only conventional zone files can have shared
291 * writeable mappings.
292 */
293 if (zonefs_inode_is_seq(inode))
294 return VM_FAULT_NOPAGE;
295
296 sb_start_pagefault(inode->i_sb);
297 file_update_time(vmf->vma->vm_file);
298
299 /* Serialize against truncates */
300 filemap_invalidate_lock_shared(inode->i_mapping);
301 ret = iomap_page_mkwrite(vmf, &zonefs_write_iomap_ops);
302 filemap_invalidate_unlock_shared(inode->i_mapping);
303
304 sb_end_pagefault(inode->i_sb);
305 return ret;
306}
307
308static const struct vm_operations_struct zonefs_file_vm_ops = {
309 .fault = filemap_fault,
310 .map_pages = filemap_map_pages,
311 .page_mkwrite = zonefs_filemap_page_mkwrite,
312};
313
314static int zonefs_file_mmap(struct file *file, struct vm_area_struct *vma)
315{
316 /*
317 * Conventional zones accept random writes, so their files can support
318 * shared writable mappings. For sequential zone files, only read
319 * mappings are possible since there are no guarantees for write
320 * ordering between msync() and page cache writeback.
321 */
322 if (zonefs_inode_is_seq(file_inode(file)) &&
323 (vma->vm_flags & VM_SHARED) && (vma->vm_flags & VM_MAYWRITE))
324 return -EINVAL;
325
326 file_accessed(file);
327 vma->vm_ops = &zonefs_file_vm_ops;
328
329 return 0;
330}
331
332static loff_t zonefs_file_llseek(struct file *file, loff_t offset, int whence)
333{
334 loff_t isize = i_size_read(file_inode(file));
335
336 /*
337 * Seeks are limited to below the zone size for conventional zones
338 * and below the zone write pointer for sequential zones. In both
339 * cases, this limit is the inode size.
340 */
341 return generic_file_llseek_size(file, offset, whence, isize, isize);
342}
343
344static int zonefs_file_write_dio_end_io(struct kiocb *iocb, ssize_t size,
345 int error, unsigned int flags)
346{
347 struct inode *inode = file_inode(iocb->ki_filp);
348 struct zonefs_inode_info *zi = ZONEFS_I(inode);
349
350 if (error) {
351 /*
352 * For Sync IOs, error recovery is called from
353 * zonefs_file_dio_write().
354 */
355 if (!is_sync_kiocb(iocb))
356 zonefs_io_error(inode, true);
357 return error;
358 }
359
360 if (size && zonefs_inode_is_seq(inode)) {
361 /*
362 * Note that we may be seeing completions out of order,
363 * but that is not a problem since a write completed
364 * successfully necessarily means that all preceding writes
365 * were also successful. So we can safely increase the inode
366 * size to the write end location.
367 */
368 mutex_lock(&zi->i_truncate_mutex);
369 if (i_size_read(inode) < iocb->ki_pos + size) {
370 zonefs_update_stats(inode, iocb->ki_pos + size);
371 zonefs_i_size_write(inode, iocb->ki_pos + size);
372 }
373 mutex_unlock(&zi->i_truncate_mutex);
374 }
375
376 return 0;
377}
378
379static const struct iomap_dio_ops zonefs_write_dio_ops = {
380 .end_io = zonefs_file_write_dio_end_io,
381};
382
383/*
384 * Do not exceed the LFS limits nor the file zone size. If pos is under the
385 * limit it becomes a short access. If it exceeds the limit, return -EFBIG.
386 */
387static loff_t zonefs_write_check_limits(struct file *file, loff_t pos,
388 loff_t count)
389{
390 struct inode *inode = file_inode(file);
391 struct zonefs_zone *z = zonefs_inode_zone(inode);
392 loff_t limit = rlimit(RLIMIT_FSIZE);
393 loff_t max_size = z->z_capacity;
394
395 if (limit != RLIM_INFINITY) {
396 if (pos >= limit) {
397 send_sig(SIGXFSZ, current, 0);
398 return -EFBIG;
399 }
400 count = min(count, limit - pos);
401 }
402
403 if (!(file->f_flags & O_LARGEFILE))
404 max_size = min_t(loff_t, MAX_NON_LFS, max_size);
405
406 if (unlikely(pos >= max_size))
407 return -EFBIG;
408
409 return min(count, max_size - pos);
410}
411
412static ssize_t zonefs_write_checks(struct kiocb *iocb, struct iov_iter *from)
413{
414 struct file *file = iocb->ki_filp;
415 struct inode *inode = file_inode(file);
416 struct zonefs_inode_info *zi = ZONEFS_I(inode);
417 struct zonefs_zone *z = zonefs_inode_zone(inode);
418 loff_t count;
419
420 if (IS_SWAPFILE(inode))
421 return -ETXTBSY;
422
423 if (!iov_iter_count(from))
424 return 0;
425
426 if ((iocb->ki_flags & IOCB_NOWAIT) && !(iocb->ki_flags & IOCB_DIRECT))
427 return -EINVAL;
428
429 if (iocb->ki_flags & IOCB_APPEND) {
430 if (zonefs_zone_is_cnv(z))
431 return -EINVAL;
432 mutex_lock(&zi->i_truncate_mutex);
433 iocb->ki_pos = z->z_wpoffset;
434 mutex_unlock(&zi->i_truncate_mutex);
435 }
436
437 count = zonefs_write_check_limits(file, iocb->ki_pos,
438 iov_iter_count(from));
439 if (count < 0)
440 return count;
441
442 iov_iter_truncate(from, count);
443 return iov_iter_count(from);
444}
445
446/*
447 * Handle direct writes. For sequential zone files, this is the only possible
448 * write path. For these files, check that the user is issuing writes
449 * sequentially from the end of the file. This code assumes that the block layer
450 * delivers write requests to the device in sequential order. This is always the
451 * case if a block IO scheduler implementing the ELEVATOR_F_ZBD_SEQ_WRITE
452 * elevator feature is being used (e.g. mq-deadline). The block layer always
453 * automatically select such an elevator for zoned block devices during the
454 * device initialization.
455 */
456static ssize_t zonefs_file_dio_write(struct kiocb *iocb, struct iov_iter *from)
457{
458 struct inode *inode = file_inode(iocb->ki_filp);
459 struct zonefs_inode_info *zi = ZONEFS_I(inode);
460 struct zonefs_zone *z = zonefs_inode_zone(inode);
461 struct super_block *sb = inode->i_sb;
462 ssize_t ret, count;
463
464 /*
465 * For async direct IOs to sequential zone files, refuse IOCB_NOWAIT
466 * as this can cause write reordering (e.g. the first aio gets EAGAIN
467 * on the inode lock but the second goes through but is now unaligned).
468 */
469 if (zonefs_zone_is_seq(z) && !is_sync_kiocb(iocb) &&
470 (iocb->ki_flags & IOCB_NOWAIT))
471 return -EOPNOTSUPP;
472
473 if (iocb->ki_flags & IOCB_NOWAIT) {
474 if (!inode_trylock(inode))
475 return -EAGAIN;
476 } else {
477 inode_lock(inode);
478 }
479
480 count = zonefs_write_checks(iocb, from);
481 if (count <= 0) {
482 ret = count;
483 goto inode_unlock;
484 }
485
486 if ((iocb->ki_pos | count) & (sb->s_blocksize - 1)) {
487 ret = -EINVAL;
488 goto inode_unlock;
489 }
490
491 /* Enforce sequential writes (append only) in sequential zones */
492 if (zonefs_zone_is_seq(z)) {
493 mutex_lock(&zi->i_truncate_mutex);
494 if (iocb->ki_pos != z->z_wpoffset) {
495 mutex_unlock(&zi->i_truncate_mutex);
496 ret = -EINVAL;
497 goto inode_unlock;
498 }
499 /*
500 * Advance the zone write pointer offset. This assumes that the
501 * IO will succeed, which is OK to do because we do not allow
502 * partial writes (IOMAP_DIO_PARTIAL is not set) and if the IO
503 * fails, the error path will correct the write pointer offset.
504 */
505 z->z_wpoffset += count;
506 zonefs_inode_account_active(inode);
507 mutex_unlock(&zi->i_truncate_mutex);
508 }
509
510 /*
511 * iomap_dio_rw() may return ENOTBLK if there was an issue with
512 * page invalidation. Overwrite that error code with EBUSY so that
513 * the user can make sense of the error.
514 */
515 ret = iomap_dio_rw(iocb, from, &zonefs_write_iomap_ops,
516 &zonefs_write_dio_ops, 0, NULL, 0);
517 if (ret == -ENOTBLK)
518 ret = -EBUSY;
519
520 /*
521 * For a failed IO or partial completion, trigger error recovery
522 * to update the zone write pointer offset to a correct value.
523 * For asynchronous IOs, zonefs_file_write_dio_end_io() may already
524 * have executed error recovery if the IO already completed when we
525 * reach here. However, we cannot know that and execute error recovery
526 * again (that will not change anything).
527 */
528 if (zonefs_zone_is_seq(z)) {
529 if (ret > 0 && ret != count)
530 ret = -EIO;
531 if (ret < 0 && ret != -EIOCBQUEUED)
532 zonefs_io_error(inode, true);
533 }
534
535inode_unlock:
536 inode_unlock(inode);
537
538 return ret;
539}
540
541static ssize_t zonefs_file_buffered_write(struct kiocb *iocb,
542 struct iov_iter *from)
543{
544 struct inode *inode = file_inode(iocb->ki_filp);
545 ssize_t ret;
546
547 /*
548 * Direct IO writes are mandatory for sequential zone files so that the
549 * write IO issuing order is preserved.
550 */
551 if (zonefs_inode_is_seq(inode))
552 return -EIO;
553
554 if (iocb->ki_flags & IOCB_NOWAIT) {
555 if (!inode_trylock(inode))
556 return -EAGAIN;
557 } else {
558 inode_lock(inode);
559 }
560
561 ret = zonefs_write_checks(iocb, from);
562 if (ret <= 0)
563 goto inode_unlock;
564
565 ret = iomap_file_buffered_write(iocb, from, &zonefs_write_iomap_ops);
566 if (ret == -EIO)
567 zonefs_io_error(inode, true);
568
569inode_unlock:
570 inode_unlock(inode);
571 if (ret > 0)
572 ret = generic_write_sync(iocb, ret);
573
574 return ret;
575}
576
577static ssize_t zonefs_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
578{
579 struct inode *inode = file_inode(iocb->ki_filp);
580 struct zonefs_zone *z = zonefs_inode_zone(inode);
581
582 if (unlikely(IS_IMMUTABLE(inode)))
583 return -EPERM;
584
585 if (sb_rdonly(inode->i_sb))
586 return -EROFS;
587
588 /* Write operations beyond the zone capacity are not allowed */
589 if (iocb->ki_pos >= z->z_capacity)
590 return -EFBIG;
591
592 if (iocb->ki_flags & IOCB_DIRECT) {
593 ssize_t ret = zonefs_file_dio_write(iocb, from);
594
595 if (ret != -ENOTBLK)
596 return ret;
597 }
598
599 return zonefs_file_buffered_write(iocb, from);
600}
601
602static int zonefs_file_read_dio_end_io(struct kiocb *iocb, ssize_t size,
603 int error, unsigned int flags)
604{
605 if (error) {
606 zonefs_io_error(file_inode(iocb->ki_filp), false);
607 return error;
608 }
609
610 return 0;
611}
612
613static const struct iomap_dio_ops zonefs_read_dio_ops = {
614 .end_io = zonefs_file_read_dio_end_io,
615};
616
617static ssize_t zonefs_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
618{
619 struct inode *inode = file_inode(iocb->ki_filp);
620 struct zonefs_inode_info *zi = ZONEFS_I(inode);
621 struct zonefs_zone *z = zonefs_inode_zone(inode);
622 struct super_block *sb = inode->i_sb;
623 loff_t isize;
624 ssize_t ret;
625
626 /* Offline zones cannot be read */
627 if (unlikely(IS_IMMUTABLE(inode) && !(inode->i_mode & 0777)))
628 return -EPERM;
629
630 if (iocb->ki_pos >= z->z_capacity)
631 return 0;
632
633 if (iocb->ki_flags & IOCB_NOWAIT) {
634 if (!inode_trylock_shared(inode))
635 return -EAGAIN;
636 } else {
637 inode_lock_shared(inode);
638 }
639
640 /* Limit read operations to written data */
641 mutex_lock(&zi->i_truncate_mutex);
642 isize = i_size_read(inode);
643 if (iocb->ki_pos >= isize) {
644 mutex_unlock(&zi->i_truncate_mutex);
645 ret = 0;
646 goto inode_unlock;
647 }
648 iov_iter_truncate(to, isize - iocb->ki_pos);
649 mutex_unlock(&zi->i_truncate_mutex);
650
651 if (iocb->ki_flags & IOCB_DIRECT) {
652 size_t count = iov_iter_count(to);
653
654 if ((iocb->ki_pos | count) & (sb->s_blocksize - 1)) {
655 ret = -EINVAL;
656 goto inode_unlock;
657 }
658 file_accessed(iocb->ki_filp);
659 ret = iomap_dio_rw(iocb, to, &zonefs_read_iomap_ops,
660 &zonefs_read_dio_ops, 0, NULL, 0);
661 } else {
662 ret = generic_file_read_iter(iocb, to);
663 if (ret == -EIO)
664 zonefs_io_error(inode, false);
665 }
666
667inode_unlock:
668 inode_unlock_shared(inode);
669
670 return ret;
671}
672
673static ssize_t zonefs_file_splice_read(struct file *in, loff_t *ppos,
674 struct pipe_inode_info *pipe,
675 size_t len, unsigned int flags)
676{
677 struct inode *inode = file_inode(in);
678 struct zonefs_inode_info *zi = ZONEFS_I(inode);
679 struct zonefs_zone *z = zonefs_inode_zone(inode);
680 loff_t isize;
681 ssize_t ret = 0;
682
683 /* Offline zones cannot be read */
684 if (unlikely(IS_IMMUTABLE(inode) && !(inode->i_mode & 0777)))
685 return -EPERM;
686
687 if (*ppos >= z->z_capacity)
688 return 0;
689
690 inode_lock_shared(inode);
691
692 /* Limit read operations to written data */
693 mutex_lock(&zi->i_truncate_mutex);
694 isize = i_size_read(inode);
695 if (*ppos >= isize)
696 len = 0;
697 else
698 len = min_t(loff_t, len, isize - *ppos);
699 mutex_unlock(&zi->i_truncate_mutex);
700
701 if (len > 0) {
702 ret = filemap_splice_read(in, ppos, pipe, len, flags);
703 if (ret == -EIO)
704 zonefs_io_error(inode, false);
705 }
706
707 inode_unlock_shared(inode);
708 return ret;
709}
710
711/*
712 * Write open accounting is done only for sequential files.
713 */
714static inline bool zonefs_seq_file_need_wro(struct inode *inode,
715 struct file *file)
716{
717 if (zonefs_inode_is_cnv(inode))
718 return false;
719
720 if (!(file->f_mode & FMODE_WRITE))
721 return false;
722
723 return true;
724}
725
726static int zonefs_seq_file_write_open(struct inode *inode)
727{
728 struct zonefs_inode_info *zi = ZONEFS_I(inode);
729 struct zonefs_zone *z = zonefs_inode_zone(inode);
730 int ret = 0;
731
732 mutex_lock(&zi->i_truncate_mutex);
733
734 if (!zi->i_wr_refcnt) {
735 struct zonefs_sb_info *sbi = ZONEFS_SB(inode->i_sb);
736 unsigned int wro = atomic_inc_return(&sbi->s_wro_seq_files);
737
738 if (sbi->s_mount_opts & ZONEFS_MNTOPT_EXPLICIT_OPEN) {
739
740 if (sbi->s_max_wro_seq_files
741 && wro > sbi->s_max_wro_seq_files) {
742 atomic_dec(&sbi->s_wro_seq_files);
743 ret = -EBUSY;
744 goto unlock;
745 }
746
747 if (i_size_read(inode) < z->z_capacity) {
748 ret = zonefs_inode_zone_mgmt(inode,
749 REQ_OP_ZONE_OPEN);
750 if (ret) {
751 atomic_dec(&sbi->s_wro_seq_files);
752 goto unlock;
753 }
754 z->z_flags |= ZONEFS_ZONE_OPEN;
755 zonefs_inode_account_active(inode);
756 }
757 }
758 }
759
760 zi->i_wr_refcnt++;
761
762unlock:
763 mutex_unlock(&zi->i_truncate_mutex);
764
765 return ret;
766}
767
768static int zonefs_file_open(struct inode *inode, struct file *file)
769{
770 int ret;
771
772 file->f_mode |= FMODE_CAN_ODIRECT;
773 ret = generic_file_open(inode, file);
774 if (ret)
775 return ret;
776
777 if (zonefs_seq_file_need_wro(inode, file))
778 return zonefs_seq_file_write_open(inode);
779
780 return 0;
781}
782
783static void zonefs_seq_file_write_close(struct inode *inode)
784{
785 struct zonefs_inode_info *zi = ZONEFS_I(inode);
786 struct zonefs_zone *z = zonefs_inode_zone(inode);
787 struct super_block *sb = inode->i_sb;
788 struct zonefs_sb_info *sbi = ZONEFS_SB(sb);
789 int ret = 0;
790
791 mutex_lock(&zi->i_truncate_mutex);
792
793 zi->i_wr_refcnt--;
794 if (zi->i_wr_refcnt)
795 goto unlock;
796
797 /*
798 * The file zone may not be open anymore (e.g. the file was truncated to
799 * its maximum size or it was fully written). For this case, we only
800 * need to decrement the write open count.
801 */
802 if (z->z_flags & ZONEFS_ZONE_OPEN) {
803 ret = zonefs_inode_zone_mgmt(inode, REQ_OP_ZONE_CLOSE);
804 if (ret) {
805 __zonefs_io_error(inode, false);
806 /*
807 * Leaving zones explicitly open may lead to a state
808 * where most zones cannot be written (zone resources
809 * exhausted). So take preventive action by remounting
810 * read-only.
811 */
812 if (z->z_flags & ZONEFS_ZONE_OPEN &&
813 !(sb->s_flags & SB_RDONLY)) {
814 zonefs_warn(sb,
815 "closing zone at %llu failed %d\n",
816 z->z_sector, ret);
817 zonefs_warn(sb,
818 "remounting filesystem read-only\n");
819 sb->s_flags |= SB_RDONLY;
820 }
821 goto unlock;
822 }
823
824 z->z_flags &= ~ZONEFS_ZONE_OPEN;
825 zonefs_inode_account_active(inode);
826 }
827
828 atomic_dec(&sbi->s_wro_seq_files);
829
830unlock:
831 mutex_unlock(&zi->i_truncate_mutex);
832}
833
834static int zonefs_file_release(struct inode *inode, struct file *file)
835{
836 /*
837 * If we explicitly open a zone we must close it again as well, but the
838 * zone management operation can fail (either due to an IO error or as
839 * the zone has gone offline or read-only). Make sure we don't fail the
840 * close(2) for user-space.
841 */
842 if (zonefs_seq_file_need_wro(inode, file))
843 zonefs_seq_file_write_close(inode);
844
845 return 0;
846}
847
848const struct file_operations zonefs_file_operations = {
849 .open = zonefs_file_open,
850 .release = zonefs_file_release,
851 .fsync = zonefs_file_fsync,
852 .mmap = zonefs_file_mmap,
853 .llseek = zonefs_file_llseek,
854 .read_iter = zonefs_file_read_iter,
855 .write_iter = zonefs_file_write_iter,
856 .splice_read = zonefs_file_splice_read,
857 .splice_write = iter_file_splice_write,
858 .iopoll = iocb_bio_iopoll,
859};