1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Copyright (C) 2017-2018 HUAWEI, Inc.
4 * http://www.huawei.com/
5 * Created by Gao Xiang <gaoxiang25@huawei.com>
6 */
7 #include "internal.h"
8 #include <linux/prefetch.h>
9
10 #include <trace/events/erofs.h>
11
erofs_readendio(struct bio * bio)12 static void erofs_readendio(struct bio *bio)
13 {
14 struct bio_vec *bvec;
15 blk_status_t err = bio->bi_status;
16 struct bvec_iter_all iter_all;
17
18 bio_for_each_segment_all(bvec, bio, iter_all) {
19 struct page *page = bvec->bv_page;
20
21 /* page is already locked */
22 DBG_BUGON(PageUptodate(page));
23
24 if (err)
25 SetPageError(page);
26 else
27 SetPageUptodate(page);
28
29 unlock_page(page);
30 /* page could be reclaimed now */
31 }
32 bio_put(bio);
33 }
34
erofs_get_meta_page(struct super_block * sb,erofs_blk_t blkaddr)35 struct page *erofs_get_meta_page(struct super_block *sb, erofs_blk_t blkaddr)
36 {
37 struct address_space *const mapping = sb->s_bdev->bd_inode->i_mapping;
38 struct page *page;
39
40 page = read_cache_page_gfp(mapping, blkaddr,
41 mapping_gfp_constraint(mapping, ~__GFP_FS));
42 /* should already be PageUptodate */
43 if (!IS_ERR(page))
44 lock_page(page);
45 return page;
46 }
47
erofs_map_blocks_flatmode(struct inode * inode,struct erofs_map_blocks * map,int flags)48 static int erofs_map_blocks_flatmode(struct inode *inode,
49 struct erofs_map_blocks *map,
50 int flags)
51 {
52 int err = 0;
53 erofs_blk_t nblocks, lastblk;
54 u64 offset = map->m_la;
55 struct erofs_inode *vi = EROFS_I(inode);
56 bool tailendpacking = (vi->datalayout == EROFS_INODE_FLAT_INLINE);
57
58 trace_erofs_map_blocks_flatmode_enter(inode, map, flags);
59
60 nblocks = DIV_ROUND_UP(inode->i_size, PAGE_SIZE);
61 lastblk = nblocks - tailendpacking;
62
63 if (offset >= inode->i_size) {
64 /* leave out-of-bound access unmapped */
65 map->m_flags = 0;
66 map->m_plen = 0;
67 goto out;
68 }
69
70 /* there is no hole in flatmode */
71 map->m_flags = EROFS_MAP_MAPPED;
72
73 if (offset < blknr_to_addr(lastblk)) {
74 map->m_pa = blknr_to_addr(vi->raw_blkaddr) + map->m_la;
75 map->m_plen = blknr_to_addr(lastblk) - offset;
76 } else if (tailendpacking) {
77 /* 2 - inode inline B: inode, [xattrs], inline last blk... */
78 struct erofs_sb_info *sbi = EROFS_SB(inode->i_sb);
79
80 map->m_pa = iloc(sbi, vi->nid) + vi->inode_isize +
81 vi->xattr_isize + erofs_blkoff(map->m_la);
82 map->m_plen = inode->i_size - offset;
83
84 /* inline data should be located in one meta block */
85 if (erofs_blkoff(map->m_pa) + map->m_plen > PAGE_SIZE) {
86 erofs_err(inode->i_sb,
87 "inline data cross block boundary @ nid %llu",
88 vi->nid);
89 DBG_BUGON(1);
90 err = -EFSCORRUPTED;
91 goto err_out;
92 }
93
94 map->m_flags |= EROFS_MAP_META;
95 } else {
96 erofs_err(inode->i_sb,
97 "internal error @ nid: %llu (size %llu), m_la 0x%llx",
98 vi->nid, inode->i_size, map->m_la);
99 DBG_BUGON(1);
100 err = -EIO;
101 goto err_out;
102 }
103
104 out:
105 map->m_llen = map->m_plen;
106
107 err_out:
108 trace_erofs_map_blocks_flatmode_exit(inode, map, flags, 0);
109 return err;
110 }
111
erofs_map_blocks(struct inode * inode,struct erofs_map_blocks * map,int flags)112 int erofs_map_blocks(struct inode *inode,
113 struct erofs_map_blocks *map, int flags)
114 {
115 if (erofs_inode_is_data_compressed(EROFS_I(inode)->datalayout)) {
116 int err = z_erofs_map_blocks_iter(inode, map, flags);
117
118 if (map->mpage) {
119 put_page(map->mpage);
120 map->mpage = NULL;
121 }
122 return err;
123 }
124 return erofs_map_blocks_flatmode(inode, map, flags);
125 }
126
erofs_read_raw_page(struct bio * bio,struct address_space * mapping,struct page * page,erofs_off_t * last_block,unsigned int nblocks,bool ra)127 static inline struct bio *erofs_read_raw_page(struct bio *bio,
128 struct address_space *mapping,
129 struct page *page,
130 erofs_off_t *last_block,
131 unsigned int nblocks,
132 bool ra)
133 {
134 struct inode *const inode = mapping->host;
135 struct super_block *const sb = inode->i_sb;
136 erofs_off_t current_block = (erofs_off_t)page->index;
137 int err;
138
139 DBG_BUGON(!nblocks);
140
141 if (PageUptodate(page)) {
142 err = 0;
143 goto has_updated;
144 }
145
146 /* note that for readpage case, bio also equals to NULL */
147 if (bio &&
148 /* not continuous */
149 *last_block + 1 != current_block) {
150 submit_bio_retry:
151 submit_bio(bio);
152 bio = NULL;
153 }
154
155 if (!bio) {
156 struct erofs_map_blocks map = {
157 .m_la = blknr_to_addr(current_block),
158 };
159 erofs_blk_t blknr;
160 unsigned int blkoff;
161
162 err = erofs_map_blocks(inode, &map, EROFS_GET_BLOCKS_RAW);
163 if (err)
164 goto err_out;
165
166 /* zero out the holed page */
167 if (!(map.m_flags & EROFS_MAP_MAPPED)) {
168 zero_user_segment(page, 0, PAGE_SIZE);
169 SetPageUptodate(page);
170
171 /* imply err = 0, see erofs_map_blocks */
172 goto has_updated;
173 }
174
175 /* for RAW access mode, m_plen must be equal to m_llen */
176 DBG_BUGON(map.m_plen != map.m_llen);
177
178 blknr = erofs_blknr(map.m_pa);
179 blkoff = erofs_blkoff(map.m_pa);
180
181 /* deal with inline page */
182 if (map.m_flags & EROFS_MAP_META) {
183 void *vsrc, *vto;
184 struct page *ipage;
185
186 DBG_BUGON(map.m_plen > PAGE_SIZE);
187
188 ipage = erofs_get_meta_page(inode->i_sb, blknr);
189
190 if (IS_ERR(ipage)) {
191 err = PTR_ERR(ipage);
192 goto err_out;
193 }
194
195 vsrc = kmap_atomic(ipage);
196 vto = kmap_atomic(page);
197 memcpy(vto, vsrc + blkoff, map.m_plen);
198 memset(vto + map.m_plen, 0, PAGE_SIZE - map.m_plen);
199 kunmap_atomic(vto);
200 kunmap_atomic(vsrc);
201 flush_dcache_page(page);
202
203 SetPageUptodate(page);
204 /* TODO: could we unlock the page earlier? */
205 unlock_page(ipage);
206 put_page(ipage);
207
208 /* imply err = 0, see erofs_map_blocks */
209 goto has_updated;
210 }
211
212 /* pa must be block-aligned for raw reading */
213 DBG_BUGON(erofs_blkoff(map.m_pa));
214
215 /* max # of continuous pages */
216 if (nblocks > DIV_ROUND_UP(map.m_plen, PAGE_SIZE))
217 nblocks = DIV_ROUND_UP(map.m_plen, PAGE_SIZE);
218 if (nblocks > BIO_MAX_PAGES)
219 nblocks = BIO_MAX_PAGES;
220
221 bio = bio_alloc(GFP_NOIO, nblocks);
222
223 bio->bi_end_io = erofs_readendio;
224 bio_set_dev(bio, sb->s_bdev);
225 bio->bi_iter.bi_sector = (sector_t)blknr <<
226 LOG_SECTORS_PER_BLOCK;
227 bio->bi_opf = REQ_OP_READ;
228 }
229
230 err = bio_add_page(bio, page, PAGE_SIZE, 0);
231 /* out of the extent or bio is full */
232 if (err < PAGE_SIZE)
233 goto submit_bio_retry;
234
235 *last_block = current_block;
236
237 /* shift in advance in case of it followed by too many gaps */
238 if (bio->bi_iter.bi_size >= bio->bi_max_vecs * PAGE_SIZE) {
239 /* err should reassign to 0 after submitting */
240 err = 0;
241 goto submit_bio_out;
242 }
243
244 return bio;
245
246 err_out:
247 /* for sync reading, set page error immediately */
248 if (!ra) {
249 SetPageError(page);
250 ClearPageUptodate(page);
251 }
252 has_updated:
253 unlock_page(page);
254
255 /* if updated manually, continuous pages has a gap */
256 if (bio)
257 submit_bio_out:
258 submit_bio(bio);
259 return err ? ERR_PTR(err) : NULL;
260 }
261
262 /*
263 * since we dont have write or truncate flows, so no inode
264 * locking needs to be held at the moment.
265 */
erofs_raw_access_readpage(struct file * file,struct page * page)266 static int erofs_raw_access_readpage(struct file *file, struct page *page)
267 {
268 erofs_off_t last_block;
269 struct bio *bio;
270
271 trace_erofs_readpage(page, true);
272
273 bio = erofs_read_raw_page(NULL, page->mapping,
274 page, &last_block, 1, false);
275
276 if (IS_ERR(bio))
277 return PTR_ERR(bio);
278
279 DBG_BUGON(bio); /* since we have only one bio -- must be NULL */
280 return 0;
281 }
282
erofs_raw_access_readpages(struct file * filp,struct address_space * mapping,struct list_head * pages,unsigned int nr_pages)283 static int erofs_raw_access_readpages(struct file *filp,
284 struct address_space *mapping,
285 struct list_head *pages,
286 unsigned int nr_pages)
287 {
288 erofs_off_t last_block;
289 struct bio *bio = NULL;
290 gfp_t gfp = readahead_gfp_mask(mapping);
291 struct page *page = list_last_entry(pages, struct page, lru);
292
293 trace_erofs_readpages(mapping->host, page, nr_pages, true);
294
295 for (; nr_pages; --nr_pages) {
296 page = list_entry(pages->prev, struct page, lru);
297
298 prefetchw(&page->flags);
299 list_del(&page->lru);
300
301 if (!add_to_page_cache_lru(page, mapping, page->index, gfp)) {
302 bio = erofs_read_raw_page(bio, mapping, page,
303 &last_block, nr_pages, true);
304
305 /* all the page errors are ignored when readahead */
306 if (IS_ERR(bio)) {
307 pr_err("%s, readahead error at page %lu of nid %llu\n",
308 __func__, page->index,
309 EROFS_I(mapping->host)->nid);
310
311 bio = NULL;
312 }
313 }
314
315 /* pages could still be locked */
316 put_page(page);
317 }
318 DBG_BUGON(!list_empty(pages));
319
320 /* the rare case (end in gaps) */
321 if (bio)
322 submit_bio(bio);
323 return 0;
324 }
325
erofs_get_block(struct inode * inode,sector_t iblock,struct buffer_head * bh,int create)326 static int erofs_get_block(struct inode *inode, sector_t iblock,
327 struct buffer_head *bh, int create)
328 {
329 struct erofs_map_blocks map = {
330 .m_la = iblock << 9,
331 };
332 int err;
333
334 err = erofs_map_blocks(inode, &map, EROFS_GET_BLOCKS_RAW);
335 if (err)
336 return err;
337
338 if (map.m_flags & EROFS_MAP_MAPPED)
339 bh->b_blocknr = erofs_blknr(map.m_pa);
340
341 return err;
342 }
343
erofs_bmap(struct address_space * mapping,sector_t block)344 static sector_t erofs_bmap(struct address_space *mapping, sector_t block)
345 {
346 struct inode *inode = mapping->host;
347
348 if (EROFS_I(inode)->datalayout == EROFS_INODE_FLAT_INLINE) {
349 erofs_blk_t blks = i_size_read(inode) >> LOG_BLOCK_SIZE;
350
351 if (block >> LOG_SECTORS_PER_BLOCK >= blks)
352 return 0;
353 }
354
355 return generic_block_bmap(mapping, block, erofs_get_block);
356 }
357
358 /* for uncompressed (aligned) files and raw access for other files */
359 const struct address_space_operations erofs_raw_access_aops = {
360 .readpage = erofs_raw_access_readpage,
361 .readpages = erofs_raw_access_readpages,
362 .bmap = erofs_bmap,
363 };
364
365