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