1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Copyright (C) 2017-2018 HUAWEI, Inc.
4 * https://www.huawei.com/
5 * Copyright (C) 2021, Alibaba Cloud
6 */
7 #include "internal.h"
8 #include <linux/filelock.h>
9 #include <linux/sched/mm.h>
10 #include <trace/events/erofs.h>
11
erofs_unmap_metabuf(struct erofs_buf * buf)12 void erofs_unmap_metabuf(struct erofs_buf *buf)
13 {
14 if (!buf->base)
15 return;
16 kunmap_local(buf->base);
17 buf->base = NULL;
18 }
19
erofs_put_metabuf(struct erofs_buf * buf)20 void erofs_put_metabuf(struct erofs_buf *buf)
21 {
22 if (!buf->page)
23 return;
24 erofs_unmap_metabuf(buf);
25 folio_put(page_folio(buf->page));
26 buf->page = NULL;
27 }
28
erofs_bread(struct erofs_buf * buf,erofs_off_t offset,bool need_kmap)29 void *erofs_bread(struct erofs_buf *buf, erofs_off_t offset, bool need_kmap)
30 {
31 pgoff_t index = (buf->off + offset) >> PAGE_SHIFT;
32 struct folio *folio = NULL;
33
34 if (buf->page) {
35 folio = page_folio(buf->page);
36 if (folio_file_page(folio, index) != buf->page)
37 erofs_unmap_metabuf(buf);
38 }
39 if (!folio || !folio_contains(folio, index)) {
40 erofs_put_metabuf(buf);
41 folio = read_cache_folio(buf->mapping, index,
42 buf->mc ? erofs_read_meta_folio : NULL, NULL);
43 if (IS_ERR(folio))
44 return folio;
45 }
46 buf->page = folio_file_page(folio, index);
47 if (!need_kmap)
48 return NULL;
49 if (!buf->base)
50 buf->base = kmap_local_page(buf->page);
51 return buf->base + (offset & ~PAGE_MASK);
52 }
53
erofs_init_metabuf(struct erofs_buf * buf,struct super_block * sb,bool in_metabox)54 int erofs_init_metabuf(struct erofs_buf *buf, struct super_block *sb,
55 bool in_metabox)
56 {
57 struct erofs_sb_info *sbi = EROFS_SB(sb);
58
59 buf->mc = false;
60 if (in_metabox) {
61 if (unlikely(!sbi->metabox_inode))
62 return -EFSCORRUPTED;
63 buf->mapping = sbi->metabox_inode->i_mapping;
64 return 0;
65 }
66 if (erofs_is_fileio_mode(sbi)) {
67 buf->mapping = sbi->managed_cache->i_mapping;
68 buf->mc = true;
69 } else {
70 buf->off = sbi->dif0.fsoff;
71 buf->mapping = sb->s_bdev->bd_mapping;
72 }
73 return 0;
74 }
75
erofs_read_metabuf(struct erofs_buf * buf,struct super_block * sb,erofs_off_t offset,bool in_metabox)76 void *erofs_read_metabuf(struct erofs_buf *buf, struct super_block *sb,
77 erofs_off_t offset, bool in_metabox)
78 {
79 int err;
80
81 err = erofs_init_metabuf(buf, sb, in_metabox);
82 if (err)
83 return ERR_PTR(err);
84 return erofs_bread(buf, offset, true);
85 }
86
erofs_map_chunks(struct inode * inode,struct erofs_map_blocks * map)87 static int erofs_map_chunks(struct inode *inode, struct erofs_map_blocks *map)
88 {
89 struct erofs_buf buf = __EROFS_BUF_INITIALIZER;
90 struct super_block *sb = inode->i_sb;
91 struct erofs_inode *vi = EROFS_I(inode);
92 struct erofs_inode_chunk_index *idx;
93 unsigned int unit = vi->chunkformat & EROFS_CHUNK_FORMAT_INDEXES ?
94 sizeof(*idx) : EROFS_BLOCK_MAP_ENTRY_SIZE;
95 erofs_blk_t addrmask = (vi->chunkformat & EROFS_CHUNK_FORMAT_48BIT) ?
96 BIT_ULL(48) - 1 : BIT_ULL(32) - 1;
97 u64 nr = map->m_la >> vi->chunkbits, chunksize = 1ULL << vi->chunkbits;
98 erofs_off_t pos = ALIGN(erofs_iloc(inode) + vi->inode_isize +
99 vi->xattr_isize, unit) + unit * nr;
100 /* m_llen will be clamped to EOF in the end */
101 erofs_off_t endpos = round_up(pos + 1, sb->s_blocksize);
102 u64 last, addr;
103
104 idx = erofs_read_metabuf(&buf, sb, pos, erofs_inode_in_metabox(inode));
105 if (IS_ERR(idx))
106 return PTR_ERR(idx);
107
108 map->m_la = nr << vi->chunkbits;
109 map->m_llen = 0;
110 nr = 0;
111 do {
112 if (unit == EROFS_BLOCK_MAP_ENTRY_SIZE) {
113 addr = le32_to_cpu(((__le32 *)idx)[nr]);
114 if (addr == (u32)EROFS_NULL_ADDR)
115 addr = EROFS_NULL_ADDR;
116 } else {
117 addr = (((u64)le16_to_cpu(idx[nr].startblk_hi) << 32) |
118 le32_to_cpu(idx[nr].startblk_lo)) & addrmask;
119 if (addr ^ (EROFS_NULL_ADDR & addrmask))
120 addr |= (u64)(le16_to_cpu(idx[nr].device_id) &
121 EROFS_SB(sb)->device_id_mask) << 48;
122 else
123 addr = EROFS_NULL_ADDR;
124 }
125 if (!nr) {
126 last = addr;
127 continue;
128 }
129 /* expand and account the prior chunk here */
130 map->m_llen += chunksize;
131 if (last != EROFS_NULL_ADDR)
132 last += erofs_blknr(sb, chunksize);
133 } while (addr == last && pos + (++nr) * unit < endpos);
134
135 if (last != EROFS_NULL_ADDR) {
136 map->m_pa = erofs_pos(sb, last & addrmask) - map->m_llen;
137 map->m_deviceid = last >> 48;
138 map->m_flags = EROFS_MAP_MAPPED;
139 }
140 if (addr == last)
141 map->m_llen += chunksize;
142 map->m_llen = min_t(erofs_off_t, map->m_llen,
143 round_up(inode->i_size - map->m_la, sb->s_blocksize));
144 erofs_put_metabuf(&buf);
145 return 0;
146 }
147
erofs_map_blocks(struct inode * inode,struct erofs_map_blocks * map)148 int erofs_map_blocks(struct inode *inode, struct erofs_map_blocks *map)
149 {
150 struct super_block *sb = inode->i_sb;
151 struct erofs_inode *vi = EROFS_I(inode);
152 bool tailinline = (vi->datalayout == EROFS_INODE_FLAT_INLINE);
153 erofs_off_t pos;
154 int err = 0;
155
156 trace_erofs_map_blocks_enter(inode, map, 0);
157 map->m_deviceid = 0;
158 map->m_flags = 0;
159 if (map->m_la >= inode->i_size)
160 goto out;
161 if (vi->datalayout == EROFS_INODE_CHUNK_BASED) {
162 err = erofs_map_chunks(inode, map);
163 } else if (tailinline || vi->startblk != EROFS_NULL_ADDR) {
164 pos = erofs_pos(sb, erofs_iblks(inode) - tailinline);
165 map->m_flags = EROFS_MAP_MAPPED;
166 if (map->m_la < pos) {
167 map->m_pa = erofs_pos(sb, vi->startblk) + map->m_la;
168 map->m_llen = pos - map->m_la;
169 } else {
170 map->m_pa = erofs_iloc(inode) + vi->inode_isize +
171 vi->xattr_isize + erofs_blkoff(sb, map->m_la);
172 map->m_llen = inode->i_size - map->m_la;
173 map->m_flags |= EROFS_MAP_META;
174 if (erofs_blkoff(sb, map->m_pa) + map->m_llen >
175 sb->s_blocksize) {
176 erofs_err(sb, "inline data across blocks @ nid %llu", vi->nid);
177 return -EFSCORRUPTED;
178 }
179 }
180 }
181 out:
182 map->m_plen = err ? 0 : map->m_llen;
183 trace_erofs_map_blocks_exit(inode, map, 0, err);
184 return err;
185 }
186
erofs_fill_from_devinfo(struct erofs_map_dev * map,struct super_block * sb,struct erofs_device_info * dif)187 static void erofs_fill_from_devinfo(struct erofs_map_dev *map,
188 struct super_block *sb, struct erofs_device_info *dif)
189 {
190 map->m_sb = sb;
191 map->m_dif = dif;
192 map->m_bdev = NULL;
193 if (dif->file && S_ISBLK(file_inode(dif->file)->i_mode))
194 map->m_bdev = file_bdev(dif->file);
195 }
196
erofs_map_dev(struct super_block * sb,struct erofs_map_dev * map)197 int erofs_map_dev(struct super_block *sb, struct erofs_map_dev *map)
198 {
199 struct erofs_dev_context *devs = EROFS_SB(sb)->devs;
200 struct erofs_device_info *dif;
201 erofs_off_t startoff;
202 int id;
203
204 erofs_fill_from_devinfo(map, sb, &EROFS_SB(sb)->dif0);
205 map->m_bdev = sb->s_bdev; /* use s_bdev for the primary device */
206 if (map->m_deviceid) {
207 down_read(&devs->rwsem);
208 dif = idr_find(&devs->tree, map->m_deviceid - 1);
209 if (!dif) {
210 up_read(&devs->rwsem);
211 return -ENODEV;
212 }
213 if (devs->flatdev) {
214 map->m_pa += erofs_pos(sb, dif->uniaddr);
215 up_read(&devs->rwsem);
216 return 0;
217 }
218 erofs_fill_from_devinfo(map, sb, dif);
219 up_read(&devs->rwsem);
220 } else if (devs->extra_devices && !devs->flatdev) {
221 down_read(&devs->rwsem);
222 idr_for_each_entry(&devs->tree, dif, id) {
223 if (!dif->uniaddr)
224 continue;
225
226 startoff = erofs_pos(sb, dif->uniaddr);
227 if (map->m_pa >= startoff &&
228 map->m_pa < startoff + erofs_pos(sb, dif->blocks)) {
229 map->m_pa -= startoff;
230 erofs_fill_from_devinfo(map, sb, dif);
231 break;
232 }
233 }
234 up_read(&devs->rwsem);
235 }
236 return 0;
237 }
238
239 /*
240 * bit 30: I/O error occurred on this folio
241 * bit 29: CPU has dirty data in D-cache (needs aliasing handling);
242 * bit 0 - 29: remaining parts to complete this folio
243 */
244 #define EROFS_ONLINEFOLIO_EIO 30
245 #define EROFS_ONLINEFOLIO_DIRTY 29
246
erofs_onlinefolio_init(struct folio * folio)247 void erofs_onlinefolio_init(struct folio *folio)
248 {
249 union {
250 atomic_t o;
251 void *v;
252 } u = { .o = ATOMIC_INIT(1) };
253
254 folio->private = u.v; /* valid only if file-backed folio is locked */
255 }
256
erofs_onlinefolio_split(struct folio * folio)257 void erofs_onlinefolio_split(struct folio *folio)
258 {
259 atomic_inc((atomic_t *)&folio->private);
260 }
261
erofs_onlinefolio_end(struct folio * folio,int err,bool dirty)262 void erofs_onlinefolio_end(struct folio *folio, int err, bool dirty)
263 {
264 int orig, v;
265
266 do {
267 orig = atomic_read((atomic_t *)&folio->private);
268 DBG_BUGON(orig <= 0);
269 v = dirty << EROFS_ONLINEFOLIO_DIRTY;
270 v |= (orig - 1) | (!!err << EROFS_ONLINEFOLIO_EIO);
271 } while (atomic_cmpxchg((atomic_t *)&folio->private, orig, v) != orig);
272
273 if (v & (BIT(EROFS_ONLINEFOLIO_DIRTY) - 1))
274 return;
275 folio->private = 0;
276 if (v & BIT(EROFS_ONLINEFOLIO_DIRTY))
277 flush_dcache_folio(folio);
278 folio_end_read(folio, !(v & BIT(EROFS_ONLINEFOLIO_EIO)));
279 }
280
281 struct erofs_iomap_iter_ctx {
282 struct page *page;
283 void *base;
284 struct inode *realinode;
285 };
286
erofs_iomap_begin(struct inode * inode,loff_t offset,loff_t length,unsigned int flags,struct iomap * iomap,struct iomap * srcmap)287 static int erofs_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
288 unsigned int flags, struct iomap *iomap, struct iomap *srcmap)
289 {
290 struct iomap_iter *iter = container_of(iomap, struct iomap_iter, iomap);
291 struct erofs_iomap_iter_ctx *ctx = iter->private;
292 struct inode *realinode = ctx ? ctx->realinode : inode;
293 struct super_block *sb = realinode->i_sb;
294 struct erofs_map_blocks map;
295 struct erofs_map_dev mdev;
296 int ret;
297
298 map.m_la = offset;
299 map.m_llen = length;
300 ret = erofs_map_blocks(realinode, &map);
301 if (ret < 0)
302 return ret;
303
304 iomap->offset = map.m_la;
305 iomap->length = map.m_llen;
306 iomap->flags = 0;
307 iomap->addr = IOMAP_NULL_ADDR;
308 if (!(map.m_flags & EROFS_MAP_MAPPED)) {
309 iomap->type = IOMAP_HOLE;
310 return 0;
311 }
312
313 if (!(map.m_flags & EROFS_MAP_META) || !erofs_inode_in_metabox(realinode)) {
314 mdev = (struct erofs_map_dev) {
315 .m_deviceid = map.m_deviceid,
316 .m_pa = map.m_pa,
317 };
318 ret = erofs_map_dev(sb, &mdev);
319 if (ret)
320 return ret;
321
322 if (flags & IOMAP_DAX)
323 iomap->dax_dev = mdev.m_dif->dax_dev;
324 else
325 iomap->bdev = mdev.m_bdev;
326 iomap->addr = mdev.m_dif->fsoff + mdev.m_pa;
327 if (flags & IOMAP_DAX)
328 iomap->addr += mdev.m_dif->dax_part_off;
329 }
330
331 if (map.m_flags & EROFS_MAP_META) {
332 iomap->type = IOMAP_INLINE;
333 /* read context should read the inlined data */
334 if (ctx) {
335 struct erofs_buf buf = __EROFS_BUF_INITIALIZER;
336 void *ptr;
337
338 ptr = erofs_read_metabuf(&buf, sb, map.m_pa,
339 erofs_inode_in_metabox(realinode));
340 if (IS_ERR(ptr))
341 return PTR_ERR(ptr);
342 iomap->inline_data = ptr;
343 ctx->page = buf.page;
344 ctx->base = buf.base;
345 }
346 } else {
347 iomap->type = IOMAP_MAPPED;
348 }
349 return 0;
350 }
351
erofs_iomap_end(struct inode * inode,loff_t pos,loff_t length,ssize_t written,unsigned int flags,struct iomap * iomap)352 static int erofs_iomap_end(struct inode *inode, loff_t pos, loff_t length,
353 ssize_t written, unsigned int flags, struct iomap *iomap)
354 {
355 struct iomap_iter *iter = container_of(iomap, struct iomap_iter, iomap);
356 struct erofs_iomap_iter_ctx *ctx = iter->private;
357
358 if (ctx && ctx->base) {
359 struct erofs_buf buf = {
360 .page = ctx->page,
361 .base = ctx->base,
362 };
363
364 DBG_BUGON(iomap->type != IOMAP_INLINE);
365 erofs_put_metabuf(&buf);
366 ctx->base = NULL;
367 }
368 return written;
369 }
370
371 static DEFINE_IOMAP_ITER_NEXT_END(erofs_iomap_next, erofs_iomap_begin,
372 erofs_iomap_end);
373
374 static const struct iomap_ops erofs_iomap_ops = {
375 .iomap_next = erofs_iomap_next,
376 };
377
erofs_fiemap(struct inode * inode,struct fiemap_extent_info * fieinfo,u64 start,u64 len)378 int erofs_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
379 u64 start, u64 len)
380 {
381 if (erofs_inode_is_data_compressed(EROFS_I(inode)->datalayout)) {
382 if (!IS_ENABLED(CONFIG_EROFS_FS_ZIP))
383 return -EOPNOTSUPP;
384 return iomap_fiemap(inode, fieinfo, start, len,
385 &z_erofs_iomap_report_ops);
386 }
387 return iomap_fiemap(inode, fieinfo, start, len, &erofs_iomap_ops);
388 }
389
390 /*
391 * since we dont have write or truncate flows, so no inode
392 * locking needs to be held at the moment.
393 */
erofs_read_folio(struct file * file,struct folio * folio)394 static int erofs_read_folio(struct file *file, struct folio *folio)
395 {
396 struct iomap_read_folio_ctx read_ctx = {
397 .ops = &iomap_bio_read_ops,
398 .cur_folio = folio,
399 };
400 bool need_iput;
401 struct erofs_iomap_iter_ctx iter_ctx = {
402 .realinode = erofs_real_inode(folio_inode(folio), &need_iput),
403 };
404
405 trace_erofs_read_folio(iter_ctx.realinode, folio, true);
406 iomap_read_folio(&erofs_iomap_ops, &read_ctx, &iter_ctx);
407 if (need_iput)
408 iput(iter_ctx.realinode);
409 return 0;
410 }
411
erofs_readahead(struct readahead_control * rac)412 static void erofs_readahead(struct readahead_control *rac)
413 {
414 struct iomap_read_folio_ctx read_ctx = {
415 .ops = &iomap_bio_read_ops,
416 .rac = rac,
417 };
418 bool need_iput;
419 struct erofs_iomap_iter_ctx iter_ctx = {
420 .realinode = erofs_real_inode(rac->mapping->host, &need_iput),
421 };
422
423 trace_erofs_readahead(iter_ctx.realinode, readahead_index(rac),
424 readahead_count(rac), true);
425 iomap_readahead(&erofs_iomap_ops, &read_ctx, &iter_ctx);
426 if (need_iput)
427 iput(iter_ctx.realinode);
428 }
429
erofs_bmap(struct address_space * mapping,sector_t block)430 static sector_t erofs_bmap(struct address_space *mapping, sector_t block)
431 {
432 return iomap_bmap(mapping, block, &erofs_iomap_ops);
433 }
434
erofs_file_read_iter(struct kiocb * iocb,struct iov_iter * to)435 static ssize_t erofs_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
436 {
437 struct inode *inode = file_inode(iocb->ki_filp);
438
439 /* no need taking (shared) inode lock since it's a ro filesystem */
440 if (!iov_iter_count(to))
441 return 0;
442
443 if (IS_ENABLED(CONFIG_FS_DAX) && IS_DAX(inode))
444 return dax_iomap_rw(iocb, to, &erofs_iomap_ops);
445
446 if ((iocb->ki_flags & IOCB_DIRECT) && inode->i_sb->s_bdev) {
447 struct erofs_iomap_iter_ctx iter_ctx = {
448 .realinode = inode,
449 };
450
451 return iomap_dio_rw(iocb, to, &erofs_iomap_ops,
452 NULL, 0, &iter_ctx, 0);
453 }
454 return filemap_read(iocb, to, 0);
455 }
456
457 /* for uncompressed (aligned) files and raw access for other files */
458 const struct address_space_operations erofs_aops = {
459 .read_folio = erofs_read_folio,
460 .readahead = erofs_readahead,
461 .bmap = erofs_bmap,
462 .direct_IO = noop_direct_IO,
463 .release_folio = iomap_release_folio,
464 .invalidate_folio = iomap_invalidate_folio,
465 };
466
467 #ifdef CONFIG_FS_DAX
erofs_dax_huge_fault(struct vm_fault * vmf,unsigned int order)468 static vm_fault_t erofs_dax_huge_fault(struct vm_fault *vmf,
469 unsigned int order)
470 {
471 return dax_iomap_fault(vmf, order, NULL, NULL, &erofs_iomap_ops);
472 }
473
erofs_dax_fault(struct vm_fault * vmf)474 static vm_fault_t erofs_dax_fault(struct vm_fault *vmf)
475 {
476 return erofs_dax_huge_fault(vmf, 0);
477 }
478
479 static const struct vm_operations_struct erofs_dax_vm_ops = {
480 .fault = erofs_dax_fault,
481 .huge_fault = erofs_dax_huge_fault,
482 };
483
erofs_file_mmap_prepare(struct vm_area_desc * desc)484 static int erofs_file_mmap_prepare(struct vm_area_desc *desc)
485 {
486 if (!IS_DAX(file_inode(desc->file)))
487 return generic_file_readonly_mmap_prepare(desc);
488
489 if (vma_desc_test_all(desc, VMA_SHARED_BIT, VMA_MAYWRITE_BIT))
490 return -EINVAL;
491
492 desc->vm_ops = &erofs_dax_vm_ops;
493 vma_desc_set_flags(desc, VMA_HUGEPAGE_BIT);
494 return 0;
495 }
496 #else
497 #define erofs_file_mmap_prepare generic_file_readonly_mmap_prepare
498 #endif
499
erofs_file_llseek(struct file * file,loff_t offset,int whence)500 static loff_t erofs_file_llseek(struct file *file, loff_t offset, int whence)
501 {
502 struct inode *inode = file->f_mapping->host;
503 const struct iomap_ops *ops = &erofs_iomap_ops;
504
505 if (erofs_inode_is_data_compressed(EROFS_I(inode)->datalayout)) {
506 if (!IS_ENABLED(CONFIG_EROFS_FS_ZIP))
507 return generic_file_llseek(file, offset, whence);
508 ops = &z_erofs_iomap_report_ops;
509 }
510
511 if (whence == SEEK_HOLE)
512 offset = iomap_seek_hole(inode, offset, ops);
513 else if (whence == SEEK_DATA)
514 offset = iomap_seek_data(inode, offset, ops);
515 else
516 return generic_file_llseek(file, offset, whence);
517
518 if (offset < 0)
519 return offset;
520 return vfs_setpos(file, offset, inode->i_sb->s_maxbytes);
521 }
522
523 const struct file_operations erofs_file_fops = {
524 .llseek = erofs_file_llseek,
525 .read_iter = erofs_file_read_iter,
526 .unlocked_ioctl = erofs_ioctl,
527 #ifdef CONFIG_COMPAT
528 .compat_ioctl = erofs_compat_ioctl,
529 #endif
530 .mmap_prepare = erofs_file_mmap_prepare,
531 .get_unmapped_area = thp_get_unmapped_area,
532 .splice_read = filemap_splice_read,
533 .setlease = generic_setlease,
534 };
535