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 = DIV_ROUND_UP(inode->i_size, EROFS_BLKSIZ);
16 lastblk = nblocks - tailendpacking;
18 /* there is no hole in flatmode */
19 map->m_flags = EROFS_MAP_MAPPED;
21 if (offset < blknr_to_addr(lastblk)) {
22 map->m_pa = blknr_to_addr(vi->u.i_blkaddr) + map->m_la;
23 map->m_plen = blknr_to_addr(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 one meta block */
31 if (erofs_blkoff(map->m_pa) + map->m_plen > PAGE_SIZE) {
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;
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 = blknr_to_addr(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 = blknr_to_addr(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_sb_info *sbi, 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;
134 dif = sbi->devs + id;
135 if (!dif->mapped_blkaddr)
137 startoff = blknr_to_addr(dif->mapped_blkaddr);
138 length = blknr_to_addr(dif->blocks);
140 if (map->m_pa >= startoff &&
141 map->m_pa < startoff + length) {
142 map->m_pa -= startoff;
150 static int erofs_read_raw_data(struct erofs_inode *inode, char *buffer,
151 erofs_off_t size, erofs_off_t offset)
153 struct erofs_map_blocks map = {
156 struct erofs_map_dev mdev;
158 erofs_off_t ptr = offset;
160 while (ptr < offset + size) {
161 char *const estart = buffer + ptr - offset;
165 ret = erofs_map_blocks(inode, &map, 0);
169 DBG_BUGON(map.m_plen != map.m_llen);
171 mdev = (struct erofs_map_dev) {
172 .m_deviceid = map.m_deviceid,
175 ret = erofs_map_dev(&sbi, &mdev);
180 eend = min(offset + size, map.m_la + map.m_llen);
181 DBG_BUGON(ptr < map.m_la);
183 if (!(map.m_flags & EROFS_MAP_MAPPED)) {
186 memset(estart, 0, offset + size - ptr);
190 memset(estart, 0, eend - ptr);
195 if (ptr > map.m_la) {
196 mdev.m_pa += ptr - map.m_la;
200 ret = erofs_dev_read(mdev.m_deviceid, estart, mdev.m_pa,
209 static int z_erofs_read_data(struct erofs_inode *inode, char *buffer,
210 erofs_off_t size, erofs_off_t offset)
212 erofs_off_t end, length, skip;
213 struct erofs_map_blocks map = {
216 struct erofs_map_dev mdev;
218 unsigned int bufsize = 0;
223 while (end > offset) {
226 ret = z_erofs_map_blocks_iter(inode, &map, 0);
230 /* no device id here, thus it will always succeed */
231 mdev = (struct erofs_map_dev) {
234 ret = erofs_map_dev(&sbi, &mdev);
241 * trim to the needed size if the returned extent is quite
242 * larger than requested, and set up partial flag as well.
244 if (end < map.m_la + map.m_llen) {
245 length = end - map.m_la;
248 DBG_BUGON(end != map.m_la + map.m_llen);
250 partial = !(map.m_flags & EROFS_MAP_FULL_MAPPED);
253 if (map.m_la < offset) {
254 skip = offset - map.m_la;
261 if (!(map.m_flags & EROFS_MAP_MAPPED)) {
262 memset(buffer + end - offset, 0, length);
267 if (map.m_plen > bufsize) {
268 bufsize = map.m_plen;
269 raw = realloc(raw, bufsize);
275 ret = erofs_dev_read(mdev.m_deviceid, raw, mdev.m_pa, map.m_plen);
279 ret = z_erofs_decompress(&(struct z_erofs_decompress_req) {
281 .out = buffer + end - offset,
283 .inputsize = map.m_plen,
284 .decodedlength = length,
285 .alg = map.m_algorithmformat,
286 .partial_decoding = partial
293 return ret < 0 ? ret : 0;
296 int erofs_pread(struct erofs_inode *inode, char *buf,
297 erofs_off_t count, erofs_off_t offset)
299 switch (inode->datalayout) {
300 case EROFS_INODE_FLAT_PLAIN:
301 case EROFS_INODE_FLAT_INLINE:
302 case EROFS_INODE_CHUNK_BASED:
303 return erofs_read_raw_data(inode, buf, count, offset);
304 case EROFS_INODE_FLAT_COMPRESSION_LEGACY:
305 case EROFS_INODE_FLAT_COMPRESSION:
306 return z_erofs_read_data(inode, buf, count, offset);