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 unwritten 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 iomap_bio_read_folio(folio, ops: &zonefs_read_iomap_ops);
116 return 0;
117}
118
119static void zonefs_readahead(struct readahead_control *rac)
120{
121 iomap_bio_readahead(rac, ops: &zonefs_read_iomap_ops);
122}
123
124/*
125 * Map blocks for page writeback. This is used only on conventional zone files,
126 * which implies that the page range can only be within the fixed inode size.
127 */
128static ssize_t zonefs_writeback_range(struct iomap_writepage_ctx *wpc,
129 struct folio *folio, u64 offset, unsigned len, u64 end_pos)
130{
131 struct zonefs_zone *z = zonefs_inode_zone(inode: wpc->inode);
132
133 if (WARN_ON_ONCE(zonefs_zone_is_seq(z)))
134 return -EIO;
135 if (WARN_ON_ONCE(offset >= i_size_read(wpc->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 int error;
142
143 error = zonefs_write_iomap_begin(inode: wpc->inode, offset,
144 length: z->z_capacity - offset, IOMAP_WRITE,
145 iomap: &wpc->iomap, NULL);
146 if (error)
147 return error;
148 }
149
150 return iomap_add_to_ioend(wpc, folio, pos: offset, end_pos, dirty_len: len);
151}
152
153static const struct iomap_writeback_ops zonefs_writeback_ops = {
154 .writeback_range = zonefs_writeback_range,
155 .writeback_submit = iomap_ioend_writeback_submit,
156};
157
158static int zonefs_writepages(struct address_space *mapping,
159 struct writeback_control *wbc)
160{
161 struct iomap_writepage_ctx wpc = {
162 .inode = mapping->host,
163 .wbc = wbc,
164 .ops = &zonefs_writeback_ops,
165 };
166
167 return iomap_writepages(wpc: &wpc);
168}
169
170static int zonefs_swap_activate(struct swap_info_struct *sis,
171 struct file *swap_file, sector_t *span)
172{
173 struct inode *inode = file_inode(f: swap_file);
174
175 if (zonefs_inode_is_seq(inode)) {
176 zonefs_err(inode->i_sb,
177 "swap file: not a conventional zone file\n");
178 return -EINVAL;
179 }
180
181 return iomap_swapfile_activate(sis, swap_file, pagespan: span,
182 ops: &zonefs_read_iomap_ops);
183}
184
185const struct address_space_operations zonefs_file_aops = {
186 .read_folio = zonefs_read_folio,
187 .readahead = zonefs_readahead,
188 .writepages = zonefs_writepages,
189 .dirty_folio = iomap_dirty_folio,
190 .release_folio = iomap_release_folio,
191 .invalidate_folio = iomap_invalidate_folio,
192 .migrate_folio = filemap_migrate_folio,
193 .is_partially_uptodate = iomap_is_partially_uptodate,
194 .error_remove_folio = generic_error_remove_folio,
195 .swap_activate = zonefs_swap_activate,
196};
197
198int zonefs_file_truncate(struct inode *inode, loff_t isize)
199{
200 struct zonefs_inode_info *zi = ZONEFS_I(inode);
201 struct zonefs_zone *z = zonefs_inode_zone(inode);
202 loff_t old_isize;
203 enum req_op op;
204 int ret = 0;
205
206 /*
207 * Only sequential zone files can be truncated and truncation is allowed
208 * only down to a 0 size, which is equivalent to a zone reset, and to
209 * the maximum file size, which is equivalent to a zone finish.
210 */
211 if (!zonefs_zone_is_seq(z))
212 return -EPERM;
213
214 if (!isize)
215 op = REQ_OP_ZONE_RESET;
216 else if (isize == z->z_capacity)
217 op = REQ_OP_ZONE_FINISH;
218 else
219 return -EPERM;
220
221 inode_dio_wait(inode);
222
223 /* Serialize against page faults */
224 filemap_invalidate_lock(mapping: inode->i_mapping);
225
226 /* Serialize against zonefs_iomap_begin() */
227 mutex_lock(&zi->i_truncate_mutex);
228
229 old_isize = i_size_read(inode);
230 if (isize == old_isize)
231 goto unlock;
232
233 ret = zonefs_inode_zone_mgmt(inode, op);
234 if (ret)
235 goto unlock;
236
237 /*
238 * If the mount option ZONEFS_MNTOPT_EXPLICIT_OPEN is set,
239 * take care of open zones.
240 */
241 if (z->z_flags & ZONEFS_ZONE_OPEN) {
242 /*
243 * Truncating a zone to EMPTY or FULL is the equivalent of
244 * closing the zone. For a truncation to 0, we need to
245 * re-open the zone to ensure new writes can be processed.
246 * For a truncation to the maximum file size, the zone is
247 * closed and writes cannot be accepted anymore, so clear
248 * the open flag.
249 */
250 if (!isize)
251 ret = zonefs_inode_zone_mgmt(inode, op: REQ_OP_ZONE_OPEN);
252 else
253 z->z_flags &= ~ZONEFS_ZONE_OPEN;
254 }
255
256 zonefs_update_stats(inode, new_isize: isize);
257 truncate_setsize(inode, newsize: isize);
258 z->z_wpoffset = isize;
259 zonefs_inode_account_active(inode);
260
261unlock:
262 mutex_unlock(lock: &zi->i_truncate_mutex);
263 filemap_invalidate_unlock(mapping: inode->i_mapping);
264
265 return ret;
266}
267
268static int zonefs_file_fsync(struct file *file, loff_t start, loff_t end,
269 int datasync)
270{
271 struct inode *inode = file_inode(f: file);
272 int ret = 0;
273
274 if (unlikely(IS_IMMUTABLE(inode)))
275 return -EPERM;
276
277 /*
278 * Since only direct writes are allowed in sequential files, page cache
279 * flush is needed only for conventional zone files.
280 */
281 if (zonefs_inode_is_cnv(inode))
282 ret = file_write_and_wait_range(file, start, end);
283 if (!ret)
284 ret = blkdev_issue_flush(bdev: inode->i_sb->s_bdev);
285
286 if (ret)
287 zonefs_io_error(inode, write: true);
288
289 return ret;
290}
291
292static vm_fault_t zonefs_filemap_page_mkwrite(struct vm_fault *vmf)
293{
294 struct inode *inode = file_inode(f: vmf->vma->vm_file);
295 vm_fault_t ret;
296
297 if (unlikely(IS_IMMUTABLE(inode)))
298 return VM_FAULT_SIGBUS;
299
300 /*
301 * Sanity check: only conventional zone files can have shared
302 * writeable mappings.
303 */
304 if (zonefs_inode_is_seq(inode))
305 return VM_FAULT_NOPAGE;
306
307 sb_start_pagefault(sb: inode->i_sb);
308 file_update_time(file: vmf->vma->vm_file);
309
310 /* Serialize against truncates */
311 filemap_invalidate_lock_shared(mapping: inode->i_mapping);
312 ret = iomap_page_mkwrite(vmf, ops: &zonefs_write_iomap_ops, NULL);
313 filemap_invalidate_unlock_shared(mapping: inode->i_mapping);
314
315 sb_end_pagefault(sb: inode->i_sb);
316 return ret;
317}
318
319static const struct vm_operations_struct zonefs_file_vm_ops = {
320 .fault = filemap_fault,
321 .map_pages = filemap_map_pages,
322 .page_mkwrite = zonefs_filemap_page_mkwrite,
323};
324
325static int zonefs_file_mmap_prepare(struct vm_area_desc *desc)
326{
327 struct file *file = desc->file;
328
329 /*
330 * Conventional zones accept random writes, so their files can support
331 * shared writable mappings. For sequential zone files, only read
332 * mappings are possible since there are no guarantees for write
333 * ordering between msync() and page cache writeback.
334 */
335 if (zonefs_inode_is_seq(inode: file_inode(f: file)) &&
336 (desc->vm_flags & VM_SHARED) && (desc->vm_flags & VM_MAYWRITE))
337 return -EINVAL;
338
339 file_accessed(file);
340 desc->vm_ops = &zonefs_file_vm_ops;
341
342 return 0;
343}
344
345static loff_t zonefs_file_llseek(struct file *file, loff_t offset, int whence)
346{
347 loff_t isize = i_size_read(inode: file_inode(f: file));
348
349 /*
350 * Seeks are limited to below the zone size for conventional zones
351 * and below the zone write pointer for sequential zones. In both
352 * cases, this limit is the inode size.
353 */
354 return generic_file_llseek_size(file, offset, whence, maxsize: isize, eof: isize);
355}
356
357static int zonefs_file_write_dio_end_io(struct kiocb *iocb, ssize_t size,
358 int error, unsigned int flags)
359{
360 struct inode *inode = file_inode(f: iocb->ki_filp);
361 struct zonefs_inode_info *zi = ZONEFS_I(inode);
362
363 if (error) {
364 /*
365 * For Sync IOs, error recovery is called from
366 * zonefs_file_dio_write().
367 */
368 if (!is_sync_kiocb(kiocb: iocb))
369 zonefs_io_error(inode, write: true);
370 return error;
371 }
372
373 if (size && zonefs_inode_is_seq(inode)) {
374 /*
375 * Note that we may be seeing completions out of order,
376 * but that is not a problem since a write completed
377 * successfully necessarily means that all preceding writes
378 * were also successful. So we can safely increase the inode
379 * size to the write end location.
380 */
381 mutex_lock(&zi->i_truncate_mutex);
382 if (i_size_read(inode) < iocb->ki_pos + size) {
383 zonefs_update_stats(inode, new_isize: iocb->ki_pos + size);
384 zonefs_i_size_write(inode, isize: iocb->ki_pos + size);
385 }
386 mutex_unlock(lock: &zi->i_truncate_mutex);
387 }
388
389 return 0;
390}
391
392static const struct iomap_dio_ops zonefs_write_dio_ops = {
393 .end_io = zonefs_file_write_dio_end_io,
394};
395
396/*
397 * Do not exceed the LFS limits nor the file zone size. If pos is under the
398 * limit it becomes a short access. If it exceeds the limit, return -EFBIG.
399 */
400static loff_t zonefs_write_check_limits(struct file *file, loff_t pos,
401 loff_t count)
402{
403 struct inode *inode = file_inode(f: file);
404 struct zonefs_zone *z = zonefs_inode_zone(inode);
405 loff_t limit = rlimit(RLIMIT_FSIZE);
406 loff_t max_size = z->z_capacity;
407
408 if (limit != RLIM_INFINITY) {
409 if (pos >= limit) {
410 send_sig(SIGXFSZ, current, 0);
411 return -EFBIG;
412 }
413 count = min(count, limit - pos);
414 }
415
416 if (!(file->f_flags & O_LARGEFILE))
417 max_size = min_t(loff_t, MAX_NON_LFS, max_size);
418
419 if (unlikely(pos >= max_size))
420 return -EFBIG;
421
422 return min(count, max_size - pos);
423}
424
425static ssize_t zonefs_write_checks(struct kiocb *iocb, struct iov_iter *from)
426{
427 struct file *file = iocb->ki_filp;
428 struct inode *inode = file_inode(f: file);
429 struct zonefs_inode_info *zi = ZONEFS_I(inode);
430 struct zonefs_zone *z = zonefs_inode_zone(inode);
431 loff_t count;
432
433 if (IS_SWAPFILE(inode))
434 return -ETXTBSY;
435
436 if (!iov_iter_count(i: from))
437 return 0;
438
439 if ((iocb->ki_flags & IOCB_NOWAIT) && !(iocb->ki_flags & IOCB_DIRECT))
440 return -EINVAL;
441
442 if (iocb->ki_flags & IOCB_APPEND) {
443 if (zonefs_zone_is_cnv(z))
444 return -EINVAL;
445 mutex_lock(&zi->i_truncate_mutex);
446 iocb->ki_pos = z->z_wpoffset;
447 mutex_unlock(lock: &zi->i_truncate_mutex);
448 }
449
450 count = zonefs_write_check_limits(file, pos: iocb->ki_pos,
451 count: iov_iter_count(i: from));
452 if (count < 0)
453 return count;
454
455 iov_iter_truncate(i: from, count);
456 return iov_iter_count(i: from);
457}
458
459/*
460 * Handle direct writes. For sequential zone files, this is the only possible
461 * write path. For these files, check that the user is issuing writes
462 * sequentially from the end of the file. This code assumes that the block layer
463 * delivers write requests to the device in sequential order. This is always the
464 * case if a block IO scheduler implementing the ELEVATOR_F_ZBD_SEQ_WRITE
465 * elevator feature is being used (e.g. mq-deadline). The block layer always
466 * automatically select such an elevator for zoned block devices during the
467 * device initialization.
468 */
469static ssize_t zonefs_file_dio_write(struct kiocb *iocb, struct iov_iter *from)
470{
471 struct inode *inode = file_inode(f: iocb->ki_filp);
472 struct zonefs_inode_info *zi = ZONEFS_I(inode);
473 struct zonefs_zone *z = zonefs_inode_zone(inode);
474 struct super_block *sb = inode->i_sb;
475 ssize_t ret, count;
476
477 /*
478 * For async direct IOs to sequential zone files, refuse IOCB_NOWAIT
479 * as this can cause write reordering (e.g. the first aio gets EAGAIN
480 * on the inode lock but the second goes through but is now unaligned).
481 */
482 if (zonefs_zone_is_seq(z) && !is_sync_kiocb(kiocb: iocb) &&
483 (iocb->ki_flags & IOCB_NOWAIT))
484 return -EOPNOTSUPP;
485
486 if (iocb->ki_flags & IOCB_NOWAIT) {
487 if (!inode_trylock(inode))
488 return -EAGAIN;
489 } else {
490 inode_lock(inode);
491 }
492
493 count = zonefs_write_checks(iocb, from);
494 if (count <= 0) {
495 ret = count;
496 goto inode_unlock;
497 }
498
499 if ((iocb->ki_pos | count) & (sb->s_blocksize - 1)) {
500 ret = -EINVAL;
501 goto inode_unlock;
502 }
503
504 /* Enforce sequential writes (append only) in sequential zones */
505 if (zonefs_zone_is_seq(z)) {
506 mutex_lock(&zi->i_truncate_mutex);
507 if (iocb->ki_pos != z->z_wpoffset) {
508 mutex_unlock(lock: &zi->i_truncate_mutex);
509 ret = -EINVAL;
510 goto inode_unlock;
511 }
512 /*
513 * Advance the zone write pointer offset. This assumes that the
514 * IO will succeed, which is OK to do because we do not allow
515 * partial writes (IOMAP_DIO_PARTIAL is not set) and if the IO
516 * fails, the error path will correct the write pointer offset.
517 */
518 z->z_wpoffset += count;
519 zonefs_inode_account_active(inode);
520 mutex_unlock(lock: &zi->i_truncate_mutex);
521 }
522
523 /*
524 * iomap_dio_rw() may return ENOTBLK if there was an issue with
525 * page invalidation. Overwrite that error code with EBUSY so that
526 * the user can make sense of the error.
527 */
528 ret = iomap_dio_rw(iocb, iter: from, ops: &zonefs_write_iomap_ops,
529 dops: &zonefs_write_dio_ops, dio_flags: 0, NULL, done_before: 0);
530 if (ret == -ENOTBLK)
531 ret = -EBUSY;
532
533 /*
534 * For a failed IO or partial completion, trigger error recovery
535 * to update the zone write pointer offset to a correct value.
536 * For asynchronous IOs, zonefs_file_write_dio_end_io() may already
537 * have executed error recovery if the IO already completed when we
538 * reach here. However, we cannot know that and execute error recovery
539 * again (that will not change anything).
540 */
541 if (zonefs_zone_is_seq(z)) {
542 if (ret > 0 && ret != count)
543 ret = -EIO;
544 if (ret < 0 && ret != -EIOCBQUEUED)
545 zonefs_io_error(inode, write: true);
546 }
547
548inode_unlock:
549 inode_unlock(inode);
550
551 return ret;
552}
553
554static ssize_t zonefs_file_buffered_write(struct kiocb *iocb,
555 struct iov_iter *from)
556{
557 struct inode *inode = file_inode(f: iocb->ki_filp);
558 ssize_t ret;
559
560 /*
561 * Direct IO writes are mandatory for sequential zone files so that the
562 * write IO issuing order is preserved.
563 */
564 if (zonefs_inode_is_seq(inode))
565 return -EIO;
566
567 if (iocb->ki_flags & IOCB_NOWAIT) {
568 if (!inode_trylock(inode))
569 return -EAGAIN;
570 } else {
571 inode_lock(inode);
572 }
573
574 ret = zonefs_write_checks(iocb, from);
575 if (ret <= 0)
576 goto inode_unlock;
577
578 ret = iomap_file_buffered_write(iocb, from, ops: &zonefs_write_iomap_ops,
579 NULL, NULL);
580 if (ret == -EIO)
581 zonefs_io_error(inode, write: true);
582
583inode_unlock:
584 inode_unlock(inode);
585 if (ret > 0)
586 ret = generic_write_sync(iocb, count: ret);
587
588 return ret;
589}
590
591static ssize_t zonefs_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
592{
593 struct inode *inode = file_inode(f: iocb->ki_filp);
594 struct zonefs_zone *z = zonefs_inode_zone(inode);
595
596 if (unlikely(IS_IMMUTABLE(inode)))
597 return -EPERM;
598
599 if (sb_rdonly(sb: inode->i_sb))
600 return -EROFS;
601
602 /* Write operations beyond the zone capacity are not allowed */
603 if (iocb->ki_pos >= z->z_capacity)
604 return -EFBIG;
605
606 if (iocb->ki_flags & IOCB_DIRECT) {
607 ssize_t ret = zonefs_file_dio_write(iocb, from);
608
609 if (ret != -ENOTBLK)
610 return ret;
611 }
612
613 return zonefs_file_buffered_write(iocb, from);
614}
615
616static int zonefs_file_read_dio_end_io(struct kiocb *iocb, ssize_t size,
617 int error, unsigned int flags)
618{
619 if (error) {
620 zonefs_io_error(inode: file_inode(f: iocb->ki_filp), write: false);
621 return error;
622 }
623
624 return 0;
625}
626
627static const struct iomap_dio_ops zonefs_read_dio_ops = {
628 .end_io = zonefs_file_read_dio_end_io,
629};
630
631static ssize_t zonefs_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
632{
633 struct inode *inode = file_inode(f: iocb->ki_filp);
634 struct zonefs_inode_info *zi = ZONEFS_I(inode);
635 struct zonefs_zone *z = zonefs_inode_zone(inode);
636 struct super_block *sb = inode->i_sb;
637 loff_t isize;
638 ssize_t ret;
639
640 /* Offline zones cannot be read */
641 if (unlikely(IS_IMMUTABLE(inode) && !(inode->i_mode & 0777)))
642 return -EPERM;
643
644 if (iocb->ki_pos >= z->z_capacity)
645 return 0;
646
647 if (iocb->ki_flags & IOCB_NOWAIT) {
648 if (!inode_trylock_shared(inode))
649 return -EAGAIN;
650 } else {
651 inode_lock_shared(inode);
652 }
653
654 /* Limit read operations to written data */
655 mutex_lock(&zi->i_truncate_mutex);
656 isize = i_size_read(inode);
657 if (iocb->ki_pos >= isize) {
658 mutex_unlock(lock: &zi->i_truncate_mutex);
659 ret = 0;
660 goto inode_unlock;
661 }
662 iov_iter_truncate(i: to, count: isize - iocb->ki_pos);
663 mutex_unlock(lock: &zi->i_truncate_mutex);
664
665 if (iocb->ki_flags & IOCB_DIRECT) {
666 size_t count = iov_iter_count(i: to);
667
668 if ((iocb->ki_pos | count) & (sb->s_blocksize - 1)) {
669 ret = -EINVAL;
670 goto inode_unlock;
671 }
672 file_accessed(file: iocb->ki_filp);
673 ret = iomap_dio_rw(iocb, iter: to, ops: &zonefs_read_iomap_ops,
674 dops: &zonefs_read_dio_ops, dio_flags: 0, NULL, done_before: 0);
675 } else {
676 ret = generic_file_read_iter(iocb, to);
677 if (ret == -EIO)
678 zonefs_io_error(inode, write: false);
679 }
680
681inode_unlock:
682 inode_unlock_shared(inode);
683
684 return ret;
685}
686
687static ssize_t zonefs_file_splice_read(struct file *in, loff_t *ppos,
688 struct pipe_inode_info *pipe,
689 size_t len, unsigned int flags)
690{
691 struct inode *inode = file_inode(f: in);
692 struct zonefs_inode_info *zi = ZONEFS_I(inode);
693 struct zonefs_zone *z = zonefs_inode_zone(inode);
694 loff_t isize;
695 ssize_t ret = 0;
696
697 /* Offline zones cannot be read */
698 if (unlikely(IS_IMMUTABLE(inode) && !(inode->i_mode & 0777)))
699 return -EPERM;
700
701 if (*ppos >= z->z_capacity)
702 return 0;
703
704 inode_lock_shared(inode);
705
706 /* Limit read operations to written data */
707 mutex_lock(&zi->i_truncate_mutex);
708 isize = i_size_read(inode);
709 if (*ppos >= isize)
710 len = 0;
711 else
712 len = min_t(loff_t, len, isize - *ppos);
713 mutex_unlock(lock: &zi->i_truncate_mutex);
714
715 if (len > 0) {
716 ret = filemap_splice_read(in, ppos, pipe, len, flags);
717 if (ret == -EIO)
718 zonefs_io_error(inode, write: false);
719 }
720
721 inode_unlock_shared(inode);
722 return ret;
723}
724
725/*
726 * Write open accounting is done only for sequential files.
727 */
728static inline bool zonefs_seq_file_need_wro(struct inode *inode,
729 struct file *file)
730{
731 if (zonefs_inode_is_cnv(inode))
732 return false;
733
734 if (!(file->f_mode & FMODE_WRITE))
735 return false;
736
737 return true;
738}
739
740static int zonefs_seq_file_write_open(struct inode *inode)
741{
742 struct zonefs_inode_info *zi = ZONEFS_I(inode);
743 struct zonefs_zone *z = zonefs_inode_zone(inode);
744 int ret = 0;
745
746 mutex_lock(&zi->i_truncate_mutex);
747
748 if (!zi->i_wr_refcnt) {
749 struct zonefs_sb_info *sbi = ZONEFS_SB(sb: inode->i_sb);
750 unsigned int wro = atomic_inc_return(v: &sbi->s_wro_seq_files);
751
752 if (sbi->s_mount_opts & ZONEFS_MNTOPT_EXPLICIT_OPEN) {
753
754 if (sbi->s_max_wro_seq_files
755 && wro > sbi->s_max_wro_seq_files) {
756 atomic_dec(v: &sbi->s_wro_seq_files);
757 ret = -EBUSY;
758 goto unlock;
759 }
760
761 if (i_size_read(inode) < z->z_capacity) {
762 ret = zonefs_inode_zone_mgmt(inode,
763 op: REQ_OP_ZONE_OPEN);
764 if (ret) {
765 atomic_dec(v: &sbi->s_wro_seq_files);
766 goto unlock;
767 }
768 z->z_flags |= ZONEFS_ZONE_OPEN;
769 zonefs_inode_account_active(inode);
770 }
771 }
772 }
773
774 zi->i_wr_refcnt++;
775
776unlock:
777 mutex_unlock(lock: &zi->i_truncate_mutex);
778
779 return ret;
780}
781
782static int zonefs_file_open(struct inode *inode, struct file *file)
783{
784 int ret;
785
786 file->f_mode |= FMODE_CAN_ODIRECT;
787 ret = generic_file_open(inode, filp: file);
788 if (ret)
789 return ret;
790
791 if (zonefs_seq_file_need_wro(inode, file))
792 return zonefs_seq_file_write_open(inode);
793
794 return 0;
795}
796
797static void zonefs_seq_file_write_close(struct inode *inode)
798{
799 struct zonefs_inode_info *zi = ZONEFS_I(inode);
800 struct zonefs_zone *z = zonefs_inode_zone(inode);
801 struct super_block *sb = inode->i_sb;
802 struct zonefs_sb_info *sbi = ZONEFS_SB(sb);
803 int ret = 0;
804
805 mutex_lock(&zi->i_truncate_mutex);
806
807 zi->i_wr_refcnt--;
808 if (zi->i_wr_refcnt)
809 goto unlock;
810
811 /*
812 * The file zone may not be open anymore (e.g. the file was truncated to
813 * its maximum size or it was fully written). For this case, we only
814 * need to decrement the write open count.
815 */
816 if (z->z_flags & ZONEFS_ZONE_OPEN) {
817 ret = zonefs_inode_zone_mgmt(inode, op: REQ_OP_ZONE_CLOSE);
818 if (ret) {
819 __zonefs_io_error(inode, write: false);
820 /*
821 * Leaving zones explicitly open may lead to a state
822 * where most zones cannot be written (zone resources
823 * exhausted). So take preventive action by remounting
824 * read-only.
825 */
826 if (z->z_flags & ZONEFS_ZONE_OPEN &&
827 !(sb->s_flags & SB_RDONLY)) {
828 zonefs_warn(sb,
829 "closing zone at %llu failed %d\n",
830 z->z_sector, ret);
831 zonefs_warn(sb,
832 "remounting filesystem read-only\n");
833 sb->s_flags |= SB_RDONLY;
834 }
835 goto unlock;
836 }
837
838 z->z_flags &= ~ZONEFS_ZONE_OPEN;
839 zonefs_inode_account_active(inode);
840 }
841
842 atomic_dec(v: &sbi->s_wro_seq_files);
843
844unlock:
845 mutex_unlock(lock: &zi->i_truncate_mutex);
846}
847
848static int zonefs_file_release(struct inode *inode, struct file *file)
849{
850 /*
851 * If we explicitly open a zone we must close it again as well, but the
852 * zone management operation can fail (either due to an IO error or as
853 * the zone has gone offline or read-only). Make sure we don't fail the
854 * close(2) for user-space.
855 */
856 if (zonefs_seq_file_need_wro(inode, file))
857 zonefs_seq_file_write_close(inode);
858
859 return 0;
860}
861
862const struct file_operations zonefs_file_operations = {
863 .open = zonefs_file_open,
864 .release = zonefs_file_release,
865 .fsync = zonefs_file_fsync,
866 .mmap_prepare = zonefs_file_mmap_prepare,
867 .llseek = zonefs_file_llseek,
868 .read_iter = zonefs_file_read_iter,
869 .write_iter = zonefs_file_write_iter,
870 .splice_read = zonefs_file_splice_read,
871 .splice_write = iter_file_splice_write,
872 .iopoll = iocb_bio_iopoll,
873};
874

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