1 // SPDX-License-Identifier: GPL-2.0+
3 #include "decompress.h"
5 static int erofs_map_blocks_flatmode(struct erofs_inode *inode,
6 struct erofs_map_blocks *map,
10 erofs_blk_t nblocks, lastblk;
11 u64 offset = map->m_la;
12 struct erofs_inode *vi = inode;
13 bool tailendpacking = (vi->datalayout == EROFS_INODE_FLAT_INLINE);
15 nblocks = BLK_ROUND_UP(inode->i_size);
16 lastblk = nblocks - tailendpacking;
18 /* there is no hole in flatmode */
19 map->m_flags = EROFS_MAP_MAPPED;
21 if (offset < erofs_pos(lastblk)) {
22 map->m_pa = erofs_pos(vi->u.i_blkaddr) + map->m_la;
23 map->m_plen = erofs_pos(lastblk) - offset;
24 } else if (tailendpacking) {
25 /* 2 - inode inline B: inode, [xattrs], inline last blk... */
26 map->m_pa = iloc(vi->nid) + vi->inode_isize +
27 vi->xattr_isize + erofs_blkoff(map->m_la);
28 map->m_plen = inode->i_size - offset;
30 /* inline data should be located in the same meta block */
31 if (erofs_blkoff(map->m_pa) + map->m_plen > erofs_blksiz()) {
32 erofs_err("inline data cross block boundary @ nid %" PRIu64,
39 map->m_flags |= EROFS_MAP_META;
41 erofs_err("internal error @ nid: %" PRIu64 " (size %llu), m_la 0x%" PRIx64,
42 vi->nid, (unsigned long long)inode->i_size, map->m_la);
48 map->m_llen = map->m_plen;
53 int erofs_map_blocks(struct erofs_inode *inode,
54 struct erofs_map_blocks *map, int flags)
56 struct erofs_inode *vi = inode;
57 struct erofs_inode_chunk_index *idx;
58 u8 buf[EROFS_MAX_BLOCK_SIZE];
65 if (map->m_la >= inode->i_size) {
66 /* leave out-of-bound access unmapped */
72 if (vi->datalayout != EROFS_INODE_CHUNK_BASED)
73 return erofs_map_blocks_flatmode(inode, map, flags);
75 if (vi->u.chunkformat & EROFS_CHUNK_FORMAT_INDEXES)
76 unit = sizeof(*idx); /* chunk index */
78 unit = EROFS_BLOCK_MAP_ENTRY_SIZE; /* block map */
80 chunknr = map->m_la >> vi->u.chunkbits;
81 pos = roundup(iloc(vi->nid) + vi->inode_isize +
82 vi->xattr_isize, unit) + unit * chunknr;
84 err = erofs_blk_read(buf, erofs_blknr(pos), 1);
88 map->m_la = chunknr << vi->u.chunkbits;
89 map->m_plen = min_t(erofs_off_t, 1UL << vi->u.chunkbits,
90 roundup(inode->i_size - map->m_la, erofs_blksiz()));
92 /* handle block map */
93 if (!(vi->u.chunkformat & EROFS_CHUNK_FORMAT_INDEXES)) {
94 __le32 *blkaddr = (void *)buf + erofs_blkoff(pos);
96 if (le32_to_cpu(*blkaddr) == EROFS_NULL_ADDR) {
99 map->m_pa = erofs_pos(le32_to_cpu(*blkaddr));
100 map->m_flags = EROFS_MAP_MAPPED;
104 /* parse chunk indexes */
105 idx = (void *)buf + erofs_blkoff(pos);
106 switch (le32_to_cpu(idx->blkaddr)) {
107 case EROFS_NULL_ADDR:
111 map->m_deviceid = le16_to_cpu(idx->device_id) &
113 map->m_pa = erofs_pos(le32_to_cpu(idx->blkaddr));
114 map->m_flags = EROFS_MAP_MAPPED;
118 map->m_llen = map->m_plen;
122 int erofs_map_dev(struct erofs_map_dev *map)
124 struct erofs_device_info *dif;
127 if (map->m_deviceid) {
128 if (sbi.extra_devices < map->m_deviceid)
130 } else if (sbi.extra_devices) {
131 for (id = 0; id < sbi.extra_devices; ++id) {
132 erofs_off_t startoff, length;
135 if (!dif->mapped_blkaddr)
137 startoff = erofs_pos(dif->mapped_blkaddr);
138 length = erofs_pos(dif->blocks);
140 if (map->m_pa >= startoff &&
141 map->m_pa < startoff + length) {
142 map->m_pa -= startoff;
150 int erofs_read_one_data(struct erofs_map_blocks *map, char *buffer, u64 offset,
153 struct erofs_map_dev mdev;
156 mdev = (struct erofs_map_dev) {
157 .m_deviceid = map->m_deviceid,
160 ret = erofs_map_dev(&mdev);
164 ret = erofs_dev_read(mdev.m_deviceid, buffer, mdev.m_pa + offset, len);
170 static int erofs_read_raw_data(struct erofs_inode *inode, char *buffer,
171 erofs_off_t size, erofs_off_t offset)
173 struct erofs_map_blocks map = {
177 erofs_off_t ptr = offset;
179 while (ptr < offset + size) {
180 char *const estart = buffer + ptr - offset;
181 erofs_off_t eend, moff = 0;
184 ret = erofs_map_blocks(inode, &map, 0);
188 DBG_BUGON(map.m_plen != map.m_llen);
191 eend = min(offset + size, map.m_la + map.m_llen);
192 DBG_BUGON(ptr < map.m_la);
194 if (!(map.m_flags & EROFS_MAP_MAPPED)) {
197 memset(estart, 0, offset + size - ptr);
201 memset(estart, 0, eend - ptr);
206 if (ptr > map.m_la) {
207 moff = ptr - map.m_la;
211 ret = erofs_read_one_data(&map, estart, moff, eend - map.m_la);
219 int z_erofs_read_one_data(struct erofs_inode *inode,
220 struct erofs_map_blocks *map, char *raw, char *buffer,
221 erofs_off_t skip, erofs_off_t length, bool trimmed)
223 struct erofs_map_dev mdev;
226 if (map->m_flags & EROFS_MAP_FRAGMENT) {
227 struct erofs_inode packed_inode = {
228 .nid = sbi.packed_nid,
231 ret = erofs_read_inode_from_disk(&packed_inode);
233 erofs_err("failed to read packed inode from disk");
237 return erofs_pread(&packed_inode, buffer, length - skip,
238 inode->fragmentoff + skip);
241 /* no device id here, thus it will always succeed */
242 mdev = (struct erofs_map_dev) {
245 ret = erofs_map_dev(&mdev);
251 ret = erofs_dev_read(mdev.m_deviceid, raw, mdev.m_pa, map->m_plen);
255 ret = z_erofs_decompress(&(struct z_erofs_decompress_req) {
260 map->m_algorithmformat == Z_EROFS_COMPRESSION_INTERLACED ?
261 erofs_blkoff(map->m_la) : 0,
262 .inputsize = map->m_plen,
263 .decodedlength = length,
264 .alg = map->m_algorithmformat,
265 .partial_decoding = trimmed ? true :
266 !(map->m_flags & EROFS_MAP_FULL_MAPPED) ||
267 (map->m_flags & EROFS_MAP_PARTIAL_REF),
274 static int z_erofs_read_data(struct erofs_inode *inode, char *buffer,
275 erofs_off_t size, erofs_off_t offset)
277 erofs_off_t end, length, skip;
278 struct erofs_map_blocks map = {
282 unsigned int bufsize = 0;
287 while (end > offset) {
290 ret = z_erofs_map_blocks_iter(inode, &map, 0);
295 * trim to the needed size if the returned extent is quite
296 * larger than requested, and set up partial flag as well.
298 if (end < map.m_la + map.m_llen) {
299 length = end - map.m_la;
302 DBG_BUGON(end != map.m_la + map.m_llen);
307 if (map.m_la < offset) {
308 skip = offset - map.m_la;
315 if (!(map.m_flags & EROFS_MAP_MAPPED)) {
316 memset(buffer + end - offset, 0, length);
321 if (map.m_plen > bufsize) {
322 bufsize = map.m_plen;
323 raw = realloc(raw, bufsize);
330 ret = z_erofs_read_one_data(inode, &map, raw,
331 buffer + end - offset, skip, length,
338 return ret < 0 ? ret : 0;
341 int erofs_pread(struct erofs_inode *inode, char *buf,
342 erofs_off_t count, erofs_off_t offset)
344 switch (inode->datalayout) {
345 case EROFS_INODE_FLAT_PLAIN:
346 case EROFS_INODE_FLAT_INLINE:
347 case EROFS_INODE_CHUNK_BASED:
348 return erofs_read_raw_data(inode, buf, count, offset);
349 case EROFS_INODE_COMPRESSED_FULL:
350 case EROFS_INODE_COMPRESSED_COMPACT:
351 return z_erofs_read_data(inode, buf, count, offset);