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(lock: &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(lock: &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, ops: &zonefs_read_iomap_ops);
116}
117
118static void zonefs_readahead(struct readahead_control *rac)
119{
120 iomap_readahead(rac, ops: &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 unsigned int len)
130{
131 struct zonefs_zone *z = zonefs_inode_zone(inode);
132
133 if (WARN_ON_ONCE(zonefs_zone_is_seq(z)))
134 return -EIO;
135 if (WARN_ON_ONCE(offset >= i_size_read(inode)))
136 return -EIO;
137
138 /* If the mapping is already OK, nothing needs to be done */
139 if (offset >= wpc->iomap.offset &&
140 offset < wpc->iomap.offset + wpc->iomap.length)
141 return 0;
142
143 return zonefs_write_iomap_begin(inode, offset,
144 length: z->z_capacity - offset,
145 IOMAP_WRITE, iomap: &wpc->iomap, NULL);
146}
147
148static const struct iomap_writeback_ops zonefs_writeback_ops = {
149 .map_blocks = zonefs_write_map_blocks,
150};
151
152static int zonefs_writepages(struct address_space *mapping,
153 struct writeback_control *wbc)
154{
155 struct iomap_writepage_ctx wpc = { };
156
157 return iomap_writepages(mapping, wbc, wpc: &wpc, ops: &zonefs_writeback_ops);
158}
159
160static int zonefs_swap_activate(struct swap_info_struct *sis,
161 struct file *swap_file, sector_t *span)
162{
163 struct inode *inode = file_inode(f: swap_file);
164
165 if (zonefs_inode_is_seq(inode)) {
166 zonefs_err(inode->i_sb,
167 "swap file: not a conventional zone file\n");
168 return -EINVAL;
169 }
170
171 return iomap_swapfile_activate(sis, swap_file, pagespan: span,
172 ops: &zonefs_read_iomap_ops);
173}
174
175const struct address_space_operations zonefs_file_aops = {
176 .read_folio = zonefs_read_folio,
177 .readahead = zonefs_readahead,
178 .writepages = zonefs_writepages,
179 .dirty_folio = iomap_dirty_folio,
180 .release_folio = iomap_release_folio,
181 .invalidate_folio = iomap_invalidate_folio,
182 .migrate_folio = filemap_migrate_folio,
183 .is_partially_uptodate = iomap_is_partially_uptodate,
184 .error_remove_folio = generic_error_remove_folio,
185 .swap_activate = zonefs_swap_activate,
186};
187
188int zonefs_file_truncate(struct inode *inode, loff_t isize)
189{
190 struct zonefs_inode_info *zi = ZONEFS_I(inode);
191 struct zonefs_zone *z = zonefs_inode_zone(inode);
192 loff_t old_isize;
193 enum req_op op;
194 int ret = 0;
195
196 /*
197 * Only sequential zone files can be truncated and truncation is allowed
198 * only down to a 0 size, which is equivalent to a zone reset, and to
199 * the maximum file size, which is equivalent to a zone finish.
200 */
201 if (!zonefs_zone_is_seq(z))
202 return -EPERM;
203
204 if (!isize)
205 op = REQ_OP_ZONE_RESET;
206 else if (isize == z->z_capacity)
207 op = REQ_OP_ZONE_FINISH;
208 else
209 return -EPERM;
210
211 inode_dio_wait(inode);
212
213 /* Serialize against page faults */
214 filemap_invalidate_lock(mapping: inode->i_mapping);
215
216 /* Serialize against zonefs_iomap_begin() */
217 mutex_lock(&zi->i_truncate_mutex);
218
219 old_isize = i_size_read(inode);
220 if (isize == old_isize)
221 goto unlock;
222
223 ret = zonefs_inode_zone_mgmt(inode, op);
224 if (ret)
225 goto unlock;
226
227 /*
228 * If the mount option ZONEFS_MNTOPT_EXPLICIT_OPEN is set,
229 * take care of open zones.
230 */
231 if (z->z_flags & ZONEFS_ZONE_OPEN) {
232 /*
233 * Truncating a zone to EMPTY or FULL is the equivalent of
234 * closing the zone. For a truncation to 0, we need to
235 * re-open the zone to ensure new writes can be processed.
236 * For a truncation to the maximum file size, the zone is
237 * closed and writes cannot be accepted anymore, so clear
238 * the open flag.
239 */
240 if (!isize)
241 ret = zonefs_inode_zone_mgmt(inode, op: REQ_OP_ZONE_OPEN);
242 else
243 z->z_flags &= ~ZONEFS_ZONE_OPEN;
244 }
245
246 zonefs_update_stats(inode, new_isize: isize);
247 truncate_setsize(inode, newsize: isize);
248 z->z_wpoffset = isize;
249 zonefs_inode_account_active(inode);
250
251unlock:
252 mutex_unlock(lock: &zi->i_truncate_mutex);
253 filemap_invalidate_unlock(mapping: inode->i_mapping);
254
255 return ret;
256}
257
258static int zonefs_file_fsync(struct file *file, loff_t start, loff_t end,
259 int datasync)
260{
261 struct inode *inode = file_inode(f: file);
262 int ret = 0;
263
264 if (unlikely(IS_IMMUTABLE(inode)))
265 return -EPERM;
266
267 /*
268 * Since only direct writes are allowed in sequential files, page cache
269 * flush is needed only for conventional zone files.
270 */
271 if (zonefs_inode_is_cnv(inode))
272 ret = file_write_and_wait_range(file, start, end);
273 if (!ret)
274 ret = blkdev_issue_flush(bdev: inode->i_sb->s_bdev);
275
276 if (ret)
277 zonefs_io_error(inode, write: true);
278
279 return ret;
280}
281
282static vm_fault_t zonefs_filemap_page_mkwrite(struct vm_fault *vmf)
283{
284 struct inode *inode = file_inode(f: vmf->vma->vm_file);
285 vm_fault_t ret;
286
287 if (unlikely(IS_IMMUTABLE(inode)))
288 return VM_FAULT_SIGBUS;
289
290 /*
291 * Sanity check: only conventional zone files can have shared
292 * writeable mappings.
293 */
294 if (zonefs_inode_is_seq(inode))
295 return VM_FAULT_NOPAGE;
296
297 sb_start_pagefault(sb: inode->i_sb);
298 file_update_time(file: vmf->vma->vm_file);
299
300 /* Serialize against truncates */
301 filemap_invalidate_lock_shared(mapping: inode->i_mapping);
302 ret = iomap_page_mkwrite(vmf, ops: &zonefs_write_iomap_ops);
303 filemap_invalidate_unlock_shared(mapping: inode->i_mapping);
304
305 sb_end_pagefault(sb: inode->i_sb);
306 return ret;
307}
308
309static const struct vm_operations_struct zonefs_file_vm_ops = {
310 .fault = filemap_fault,
311 .map_pages = filemap_map_pages,
312 .page_mkwrite = zonefs_filemap_page_mkwrite,
313};
314
315static int zonefs_file_mmap(struct file *file, struct vm_area_struct *vma)
316{
317 /*
318 * Conventional zones accept random writes, so their files can support
319 * shared writable mappings. For sequential zone files, only read
320 * mappings are possible since there are no guarantees for write
321 * ordering between msync() and page cache writeback.
322 */
323 if (zonefs_inode_is_seq(inode: file_inode(f: file)) &&
324 (vma->vm_flags & VM_SHARED) && (vma->vm_flags & VM_MAYWRITE))
325 return -EINVAL;
326
327 file_accessed(file);
328 vma->vm_ops = &zonefs_file_vm_ops;
329
330 return 0;
331}
332
333static loff_t zonefs_file_llseek(struct file *file, loff_t offset, int whence)
334{
335 loff_t isize = i_size_read(inode: file_inode(f: file));
336
337 /*
338 * Seeks are limited to below the zone size for conventional zones
339 * and below the zone write pointer for sequential zones. In both
340 * cases, this limit is the inode size.
341 */
342 return generic_file_llseek_size(file, offset, whence, maxsize: isize, eof: isize);
343}
344
345static int zonefs_file_write_dio_end_io(struct kiocb *iocb, ssize_t size,
346 int error, unsigned int flags)
347{
348 struct inode *inode = file_inode(f: iocb->ki_filp);
349 struct zonefs_inode_info *zi = ZONEFS_I(inode);
350
351 if (error) {
352 /*
353 * For Sync IOs, error recovery is called from
354 * zonefs_file_dio_write().
355 */
356 if (!is_sync_kiocb(kiocb: iocb))
357 zonefs_io_error(inode, write: true);
358 return error;
359 }
360
361 if (size && zonefs_inode_is_seq(inode)) {
362 /*
363 * Note that we may be seeing completions out of order,
364 * but that is not a problem since a write completed
365 * successfully necessarily means that all preceding writes
366 * were also successful. So we can safely increase the inode
367 * size to the write end location.
368 */
369 mutex_lock(&zi->i_truncate_mutex);
370 if (i_size_read(inode) < iocb->ki_pos + size) {
371 zonefs_update_stats(inode, new_isize: iocb->ki_pos + size);
372 zonefs_i_size_write(inode, isize: iocb->ki_pos + size);
373 }
374 mutex_unlock(lock: &zi->i_truncate_mutex);
375 }
376
377 return 0;
378}
379
380static const struct iomap_dio_ops zonefs_write_dio_ops = {
381 .end_io = zonefs_file_write_dio_end_io,
382};
383
384/*
385 * Do not exceed the LFS limits nor the file zone size. If pos is under the
386 * limit it becomes a short access. If it exceeds the limit, return -EFBIG.
387 */
388static loff_t zonefs_write_check_limits(struct file *file, loff_t pos,
389 loff_t count)
390{
391 struct inode *inode = file_inode(f: file);
392 struct zonefs_zone *z = zonefs_inode_zone(inode);
393 loff_t limit = rlimit(RLIMIT_FSIZE);
394 loff_t max_size = z->z_capacity;
395
396 if (limit != RLIM_INFINITY) {
397 if (pos >= limit) {
398 send_sig(SIGXFSZ, current, 0);
399 return -EFBIG;
400 }
401 count = min(count, limit - pos);
402 }
403
404 if (!(file->f_flags & O_LARGEFILE))
405 max_size = min_t(loff_t, MAX_NON_LFS, max_size);
406
407 if (unlikely(pos >= max_size))
408 return -EFBIG;
409
410 return min(count, max_size - pos);
411}
412
413static ssize_t zonefs_write_checks(struct kiocb *iocb, struct iov_iter *from)
414{
415 struct file *file = iocb->ki_filp;
416 struct inode *inode = file_inode(f: file);
417 struct zonefs_inode_info *zi = ZONEFS_I(inode);
418 struct zonefs_zone *z = zonefs_inode_zone(inode);
419 loff_t count;
420
421 if (IS_SWAPFILE(inode))
422 return -ETXTBSY;
423
424 if (!iov_iter_count(i: from))
425 return 0;
426
427 if ((iocb->ki_flags & IOCB_NOWAIT) && !(iocb->ki_flags & IOCB_DIRECT))
428 return -EINVAL;
429
430 if (iocb->ki_flags & IOCB_APPEND) {
431 if (zonefs_zone_is_cnv(z))
432 return -EINVAL;
433 mutex_lock(&zi->i_truncate_mutex);
434 iocb->ki_pos = z->z_wpoffset;
435 mutex_unlock(lock: &zi->i_truncate_mutex);
436 }
437
438 count = zonefs_write_check_limits(file, pos: iocb->ki_pos,
439 count: iov_iter_count(i: from));
440 if (count < 0)
441 return count;
442
443 iov_iter_truncate(i: from, count);
444 return iov_iter_count(i: from);
445}
446
447/*
448 * Handle direct writes. For sequential zone files, this is the only possible
449 * write path. For these files, check that the user is issuing writes
450 * sequentially from the end of the file. This code assumes that the block layer
451 * delivers write requests to the device in sequential order. This is always the
452 * case if a block IO scheduler implementing the ELEVATOR_F_ZBD_SEQ_WRITE
453 * elevator feature is being used (e.g. mq-deadline). The block layer always
454 * automatically select such an elevator for zoned block devices during the
455 * device initialization.
456 */
457static ssize_t zonefs_file_dio_write(struct kiocb *iocb, struct iov_iter *from)
458{
459 struct inode *inode = file_inode(f: iocb->ki_filp);
460 struct zonefs_inode_info *zi = ZONEFS_I(inode);
461 struct zonefs_zone *z = zonefs_inode_zone(inode);
462 struct super_block *sb = inode->i_sb;
463 ssize_t ret, count;
464
465 /*
466 * For async direct IOs to sequential zone files, refuse IOCB_NOWAIT
467 * as this can cause write reordering (e.g. the first aio gets EAGAIN
468 * on the inode lock but the second goes through but is now unaligned).
469 */
470 if (zonefs_zone_is_seq(z) && !is_sync_kiocb(kiocb: iocb) &&
471 (iocb->ki_flags & IOCB_NOWAIT))
472 return -EOPNOTSUPP;
473
474 if (iocb->ki_flags & IOCB_NOWAIT) {
475 if (!inode_trylock(inode))
476 return -EAGAIN;
477 } else {
478 inode_lock(inode);
479 }
480
481 count = zonefs_write_checks(iocb, from);
482 if (count <= 0) {
483 ret = count;
484 goto inode_unlock;
485 }
486
487 if ((iocb->ki_pos | count) & (sb->s_blocksize - 1)) {
488 ret = -EINVAL;
489 goto inode_unlock;
490 }
491
492 /* Enforce sequential writes (append only) in sequential zones */
493 if (zonefs_zone_is_seq(z)) {
494 mutex_lock(&zi->i_truncate_mutex);
495 if (iocb->ki_pos != z->z_wpoffset) {
496 mutex_unlock(lock: &zi->i_truncate_mutex);
497 ret = -EINVAL;
498 goto inode_unlock;
499 }
500 /*
501 * Advance the zone write pointer offset. This assumes that the
502 * IO will succeed, which is OK to do because we do not allow
503 * partial writes (IOMAP_DIO_PARTIAL is not set) and if the IO
504 * fails, the error path will correct the write pointer offset.
505 */
506 z->z_wpoffset += count;
507 zonefs_inode_account_active(inode);
508 mutex_unlock(lock: &zi->i_truncate_mutex);
509 }
510
511 /*
512 * iomap_dio_rw() may return ENOTBLK if there was an issue with
513 * page invalidation. Overwrite that error code with EBUSY so that
514 * the user can make sense of the error.
515 */
516 ret = iomap_dio_rw(iocb, iter: from, ops: &zonefs_write_iomap_ops,
517 dops: &zonefs_write_dio_ops, dio_flags: 0, NULL, done_before: 0);
518 if (ret == -ENOTBLK)
519 ret = -EBUSY;
520
521 /*
522 * For a failed IO or partial completion, trigger error recovery
523 * to update the zone write pointer offset to a correct value.
524 * For asynchronous IOs, zonefs_file_write_dio_end_io() may already
525 * have executed error recovery if the IO already completed when we
526 * reach here. However, we cannot know that and execute error recovery
527 * again (that will not change anything).
528 */
529 if (zonefs_zone_is_seq(z)) {
530 if (ret > 0 && ret != count)
531 ret = -EIO;
532 if (ret < 0 && ret != -EIOCBQUEUED)
533 zonefs_io_error(inode, write: true);
534 }
535
536inode_unlock:
537 inode_unlock(inode);
538
539 return ret;
540}
541
542static ssize_t zonefs_file_buffered_write(struct kiocb *iocb,
543 struct iov_iter *from)
544{
545 struct inode *inode = file_inode(f: iocb->ki_filp);
546 ssize_t ret;
547
548 /*
549 * Direct IO writes are mandatory for sequential zone files so that the
550 * write IO issuing order is preserved.
551 */
552 if (zonefs_inode_is_seq(inode))
553 return -EIO;
554
555 if (iocb->ki_flags & IOCB_NOWAIT) {
556 if (!inode_trylock(inode))
557 return -EAGAIN;
558 } else {
559 inode_lock(inode);
560 }
561
562 ret = zonefs_write_checks(iocb, from);
563 if (ret <= 0)
564 goto inode_unlock;
565
566 ret = iomap_file_buffered_write(iocb, from, ops: &zonefs_write_iomap_ops);
567 if (ret == -EIO)
568 zonefs_io_error(inode, write: true);
569
570inode_unlock:
571 inode_unlock(inode);
572 if (ret > 0)
573 ret = generic_write_sync(iocb, count: ret);
574
575 return ret;
576}
577
578static ssize_t zonefs_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
579{
580 struct inode *inode = file_inode(f: iocb->ki_filp);
581 struct zonefs_zone *z = zonefs_inode_zone(inode);
582
583 if (unlikely(IS_IMMUTABLE(inode)))
584 return -EPERM;
585
586 if (sb_rdonly(sb: inode->i_sb))
587 return -EROFS;
588
589 /* Write operations beyond the zone capacity are not allowed */
590 if (iocb->ki_pos >= z->z_capacity)
591 return -EFBIG;
592
593 if (iocb->ki_flags & IOCB_DIRECT) {
594 ssize_t ret = zonefs_file_dio_write(iocb, from);
595
596 if (ret != -ENOTBLK)
597 return ret;
598 }
599
600 return zonefs_file_buffered_write(iocb, from);
601}
602
603static int zonefs_file_read_dio_end_io(struct kiocb *iocb, ssize_t size,
604 int error, unsigned int flags)
605{
606 if (error) {
607 zonefs_io_error(inode: file_inode(f: iocb->ki_filp), write: false);
608 return error;
609 }
610
611 return 0;
612}
613
614static const struct iomap_dio_ops zonefs_read_dio_ops = {
615 .end_io = zonefs_file_read_dio_end_io,
616};
617
618static ssize_t zonefs_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
619{
620 struct inode *inode = file_inode(f: iocb->ki_filp);
621 struct zonefs_inode_info *zi = ZONEFS_I(inode);
622 struct zonefs_zone *z = zonefs_inode_zone(inode);
623 struct super_block *sb = inode->i_sb;
624 loff_t isize;
625 ssize_t ret;
626
627 /* Offline zones cannot be read */
628 if (unlikely(IS_IMMUTABLE(inode) && !(inode->i_mode & 0777)))
629 return -EPERM;
630
631 if (iocb->ki_pos >= z->z_capacity)
632 return 0;
633
634 if (iocb->ki_flags & IOCB_NOWAIT) {
635 if (!inode_trylock_shared(inode))
636 return -EAGAIN;
637 } else {
638 inode_lock_shared(inode);
639 }
640
641 /* Limit read operations to written data */
642 mutex_lock(&zi->i_truncate_mutex);
643 isize = i_size_read(inode);
644 if (iocb->ki_pos >= isize) {
645 mutex_unlock(lock: &zi->i_truncate_mutex);
646 ret = 0;
647 goto inode_unlock;
648 }
649 iov_iter_truncate(i: to, count: isize - iocb->ki_pos);
650 mutex_unlock(lock: &zi->i_truncate_mutex);
651
652 if (iocb->ki_flags & IOCB_DIRECT) {
653 size_t count = iov_iter_count(i: to);
654
655 if ((iocb->ki_pos | count) & (sb->s_blocksize - 1)) {
656 ret = -EINVAL;
657 goto inode_unlock;
658 }
659 file_accessed(file: iocb->ki_filp);
660 ret = iomap_dio_rw(iocb, iter: to, ops: &zonefs_read_iomap_ops,
661 dops: &zonefs_read_dio_ops, dio_flags: 0, NULL, done_before: 0);
662 } else {
663 ret = generic_file_read_iter(iocb, to);
664 if (ret == -EIO)
665 zonefs_io_error(inode, write: false);
666 }
667
668inode_unlock:
669 inode_unlock_shared(inode);
670
671 return ret;
672}
673
674static ssize_t zonefs_file_splice_read(struct file *in, loff_t *ppos,
675 struct pipe_inode_info *pipe,
676 size_t len, unsigned int flags)
677{
678 struct inode *inode = file_inode(f: in);
679 struct zonefs_inode_info *zi = ZONEFS_I(inode);
680 struct zonefs_zone *z = zonefs_inode_zone(inode);
681 loff_t isize;
682 ssize_t ret = 0;
683
684 /* Offline zones cannot be read */
685 if (unlikely(IS_IMMUTABLE(inode) && !(inode->i_mode & 0777)))
686 return -EPERM;
687
688 if (*ppos >= z->z_capacity)
689 return 0;
690
691 inode_lock_shared(inode);
692
693 /* Limit read operations to written data */
694 mutex_lock(&zi->i_truncate_mutex);
695 isize = i_size_read(inode);
696 if (*ppos >= isize)
697 len = 0;
698 else
699 len = min_t(loff_t, len, isize - *ppos);
700 mutex_unlock(lock: &zi->i_truncate_mutex);
701
702 if (len > 0) {
703 ret = filemap_splice_read(in, ppos, pipe, len, flags);
704 if (ret == -EIO)
705 zonefs_io_error(inode, write: false);
706 }
707
708 inode_unlock_shared(inode);
709 return ret;
710}
711
712/*
713 * Write open accounting is done only for sequential files.
714 */
715static inline bool zonefs_seq_file_need_wro(struct inode *inode,
716 struct file *file)
717{
718 if (zonefs_inode_is_cnv(inode))
719 return false;
720
721 if (!(file->f_mode & FMODE_WRITE))
722 return false;
723
724 return true;
725}
726
727static int zonefs_seq_file_write_open(struct inode *inode)
728{
729 struct zonefs_inode_info *zi = ZONEFS_I(inode);
730 struct zonefs_zone *z = zonefs_inode_zone(inode);
731 int ret = 0;
732
733 mutex_lock(&zi->i_truncate_mutex);
734
735 if (!zi->i_wr_refcnt) {
736 struct zonefs_sb_info *sbi = ZONEFS_SB(sb: inode->i_sb);
737 unsigned int wro = atomic_inc_return(v: &sbi->s_wro_seq_files);
738
739 if (sbi->s_mount_opts & ZONEFS_MNTOPT_EXPLICIT_OPEN) {
740
741 if (sbi->s_max_wro_seq_files
742 && wro > sbi->s_max_wro_seq_files) {
743 atomic_dec(v: &sbi->s_wro_seq_files);
744 ret = -EBUSY;
745 goto unlock;
746 }
747
748 if (i_size_read(inode) < z->z_capacity) {
749 ret = zonefs_inode_zone_mgmt(inode,
750 op: REQ_OP_ZONE_OPEN);
751 if (ret) {
752 atomic_dec(v: &sbi->s_wro_seq_files);
753 goto unlock;
754 }
755 z->z_flags |= ZONEFS_ZONE_OPEN;
756 zonefs_inode_account_active(inode);
757 }
758 }
759 }
760
761 zi->i_wr_refcnt++;
762
763unlock:
764 mutex_unlock(lock: &zi->i_truncate_mutex);
765
766 return ret;
767}
768
769static int zonefs_file_open(struct inode *inode, struct file *file)
770{
771 int ret;
772
773 file->f_mode |= FMODE_CAN_ODIRECT;
774 ret = generic_file_open(inode, filp: file);
775 if (ret)
776 return ret;
777
778 if (zonefs_seq_file_need_wro(inode, file))
779 return zonefs_seq_file_write_open(inode);
780
781 return 0;
782}
783
784static void zonefs_seq_file_write_close(struct inode *inode)
785{
786 struct zonefs_inode_info *zi = ZONEFS_I(inode);
787 struct zonefs_zone *z = zonefs_inode_zone(inode);
788 struct super_block *sb = inode->i_sb;
789 struct zonefs_sb_info *sbi = ZONEFS_SB(sb);
790 int ret = 0;
791
792 mutex_lock(&zi->i_truncate_mutex);
793
794 zi->i_wr_refcnt--;
795 if (zi->i_wr_refcnt)
796 goto unlock;
797
798 /*
799 * The file zone may not be open anymore (e.g. the file was truncated to
800 * its maximum size or it was fully written). For this case, we only
801 * need to decrement the write open count.
802 */
803 if (z->z_flags & ZONEFS_ZONE_OPEN) {
804 ret = zonefs_inode_zone_mgmt(inode, op: REQ_OP_ZONE_CLOSE);
805 if (ret) {
806 __zonefs_io_error(inode, write: false);
807 /*
808 * Leaving zones explicitly open may lead to a state
809 * where most zones cannot be written (zone resources
810 * exhausted). So take preventive action by remounting
811 * read-only.
812 */
813 if (z->z_flags & ZONEFS_ZONE_OPEN &&
814 !(sb->s_flags & SB_RDONLY)) {
815 zonefs_warn(sb,
816 "closing zone at %llu failed %d\n",
817 z->z_sector, ret);
818 zonefs_warn(sb,
819 "remounting filesystem read-only\n");
820 sb->s_flags |= SB_RDONLY;
821 }
822 goto unlock;
823 }
824
825 z->z_flags &= ~ZONEFS_ZONE_OPEN;
826 zonefs_inode_account_active(inode);
827 }
828
829 atomic_dec(v: &sbi->s_wro_seq_files);
830
831unlock:
832 mutex_unlock(lock: &zi->i_truncate_mutex);
833}
834
835static int zonefs_file_release(struct inode *inode, struct file *file)
836{
837 /*
838 * If we explicitly open a zone we must close it again as well, but the
839 * zone management operation can fail (either due to an IO error or as
840 * the zone has gone offline or read-only). Make sure we don't fail the
841 * close(2) for user-space.
842 */
843 if (zonefs_seq_file_need_wro(inode, file))
844 zonefs_seq_file_write_close(inode);
845
846 return 0;
847}
848
849const struct file_operations zonefs_file_operations = {
850 .open = zonefs_file_open,
851 .release = zonefs_file_release,
852 .fsync = zonefs_file_fsync,
853 .mmap = zonefs_file_mmap,
854 .llseek = zonefs_file_llseek,
855 .read_iter = zonefs_file_read_iter,
856 .write_iter = zonefs_file_write_iter,
857 .splice_read = zonefs_file_splice_read,
858 .splice_write = iter_file_splice_write,
859 .iopoll = iocb_bio_iopoll,
860};
861

source code of linux/fs/zonefs/file.c