From 65cb73057b65cdadea5eb3da2a949f3ae105cf82 Mon Sep 17 00:00:00 2001 From: Huang Jianan Date: Sat, 26 Feb 2022 15:05:49 +0800 Subject: fs/erofs: add lz4 decompression support Support EROFS lz4 compressed files. Signed-off-by: Huang Jianan --- fs/erofs/zmap.c | 601 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 601 insertions(+) create mode 100644 fs/erofs/zmap.c (limited to 'fs/erofs/zmap.c') diff --git a/fs/erofs/zmap.c b/fs/erofs/zmap.c new file mode 100644 index 0000000..be2599a --- /dev/null +++ b/fs/erofs/zmap.c @@ -0,0 +1,601 @@ +// SPDX-License-Identifier: GPL-2.0+ +#include "internal.h" + +int z_erofs_fill_inode(struct erofs_inode *vi) +{ + if (!erofs_sb_has_big_pcluster() && + vi->datalayout == EROFS_INODE_FLAT_COMPRESSION_LEGACY) { + vi->z_advise = 0; + vi->z_algorithmtype[0] = 0; + vi->z_algorithmtype[1] = 0; + vi->z_logical_clusterbits = LOG_BLOCK_SIZE; + + vi->flags |= EROFS_I_Z_INITED; + } + return 0; +} + +static int z_erofs_fill_inode_lazy(struct erofs_inode *vi) +{ + int ret; + erofs_off_t pos; + struct z_erofs_map_header *h; + char buf[sizeof(struct z_erofs_map_header)]; + + if (vi->flags & EROFS_I_Z_INITED) + return 0; + + DBG_BUGON(!erofs_sb_has_big_pcluster() && + vi->datalayout == EROFS_INODE_FLAT_COMPRESSION_LEGACY); + pos = round_up(iloc(vi->nid) + vi->inode_isize + vi->xattr_isize, 8); + + ret = erofs_dev_read(0, buf, pos, sizeof(buf)); + if (ret < 0) + return -EIO; + + h = (struct z_erofs_map_header *)buf; + vi->z_advise = le16_to_cpu(h->h_advise); + vi->z_algorithmtype[0] = h->h_algorithmtype & 15; + vi->z_algorithmtype[1] = h->h_algorithmtype >> 4; + + if (vi->z_algorithmtype[0] >= Z_EROFS_COMPRESSION_MAX) { + erofs_err("unknown compression format %u for nid %llu", + vi->z_algorithmtype[0], (unsigned long long)vi->nid); + return -EOPNOTSUPP; + } + + vi->z_logical_clusterbits = LOG_BLOCK_SIZE + (h->h_clusterbits & 7); + if (vi->datalayout == EROFS_INODE_FLAT_COMPRESSION && + !(vi->z_advise & Z_EROFS_ADVISE_BIG_PCLUSTER_1) ^ + !(vi->z_advise & Z_EROFS_ADVISE_BIG_PCLUSTER_2)) { + erofs_err("big pcluster head1/2 of compact indexes should be consistent for nid %llu", + vi->nid * 1ULL); + return -EFSCORRUPTED; + } + vi->flags |= EROFS_I_Z_INITED; + return 0; +} + +struct z_erofs_maprecorder { + struct erofs_inode *inode; + struct erofs_map_blocks *map; + void *kaddr; + + unsigned long lcn; + /* compression extent information gathered */ + u8 type, headtype; + u16 clusterofs; + u16 delta[2]; + erofs_blk_t pblk, compressedlcs; +}; + +static int z_erofs_reload_indexes(struct z_erofs_maprecorder *m, + erofs_blk_t eblk) +{ + int ret; + struct erofs_map_blocks *const map = m->map; + char *mpage = map->mpage; + + if (map->index == eblk) + return 0; + + ret = erofs_blk_read(mpage, eblk, 1); + if (ret < 0) + return -EIO; + + map->index = eblk; + + return 0; +} + +static int legacy_load_cluster_from_disk(struct z_erofs_maprecorder *m, + unsigned long lcn) +{ + struct erofs_inode *const vi = m->inode; + const erofs_off_t ibase = iloc(vi->nid); + const erofs_off_t pos = + Z_EROFS_VLE_LEGACY_INDEX_ALIGN(ibase + vi->inode_isize + + vi->xattr_isize) + + lcn * sizeof(struct z_erofs_vle_decompressed_index); + struct z_erofs_vle_decompressed_index *di; + unsigned int advise, type; + int err; + + err = z_erofs_reload_indexes(m, erofs_blknr(pos)); + if (err) + return err; + + m->lcn = lcn; + di = m->kaddr + erofs_blkoff(pos); + + advise = le16_to_cpu(di->di_advise); + type = (advise >> Z_EROFS_VLE_DI_CLUSTER_TYPE_BIT) & + ((1 << Z_EROFS_VLE_DI_CLUSTER_TYPE_BITS) - 1); + switch (type) { + case Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD: + m->clusterofs = 1 << vi->z_logical_clusterbits; + m->delta[0] = le16_to_cpu(di->di_u.delta[0]); + if (m->delta[0] & Z_EROFS_VLE_DI_D0_CBLKCNT) { + if (!(vi->z_advise & Z_EROFS_ADVISE_BIG_PCLUSTER_1)) { + DBG_BUGON(1); + return -EFSCORRUPTED; + } + m->compressedlcs = m->delta[0] & + ~Z_EROFS_VLE_DI_D0_CBLKCNT; + m->delta[0] = 1; + } + m->delta[1] = le16_to_cpu(di->di_u.delta[1]); + break; + case Z_EROFS_VLE_CLUSTER_TYPE_PLAIN: + case Z_EROFS_VLE_CLUSTER_TYPE_HEAD: + m->clusterofs = le16_to_cpu(di->di_clusterofs); + m->pblk = le32_to_cpu(di->di_u.blkaddr); + break; + default: + DBG_BUGON(1); + return -EOPNOTSUPP; + } + m->type = type; + return 0; +} + +static unsigned int decode_compactedbits(unsigned int lobits, + unsigned int lomask, + u8 *in, unsigned int pos, u8 *type) +{ + const unsigned int v = get_unaligned_le32(in + pos / 8) >> (pos & 7); + const unsigned int lo = v & lomask; + + *type = (v >> lobits) & 3; + return lo; +} + +static int get_compacted_la_distance(unsigned int lclusterbits, + unsigned int encodebits, + unsigned int vcnt, u8 *in, int i) +{ + const unsigned int lomask = (1 << lclusterbits) - 1; + unsigned int lo, d1 = 0; + u8 type; + + DBG_BUGON(i >= vcnt); + + do { + lo = decode_compactedbits(lclusterbits, lomask, + in, encodebits * i, &type); + + if (type != Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD) + return d1; + ++d1; + } while (++i < vcnt); + + /* vcnt - 1 (Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD) item */ + if (!(lo & Z_EROFS_VLE_DI_D0_CBLKCNT)) + d1 += lo - 1; + return d1; +} + +static int unpack_compacted_index(struct z_erofs_maprecorder *m, + unsigned int amortizedshift, + unsigned int eofs, bool lookahead) +{ + struct erofs_inode *const vi = m->inode; + const unsigned int lclusterbits = vi->z_logical_clusterbits; + const unsigned int lomask = (1 << lclusterbits) - 1; + unsigned int vcnt, base, lo, encodebits, nblk; + int i; + u8 *in, type; + bool big_pcluster; + + if (1 << amortizedshift == 4) + vcnt = 2; + else if (1 << amortizedshift == 2 && lclusterbits == 12) + vcnt = 16; + else + return -EOPNOTSUPP; + + big_pcluster = vi->z_advise & Z_EROFS_ADVISE_BIG_PCLUSTER_1; + encodebits = ((vcnt << amortizedshift) - sizeof(__le32)) * 8 / vcnt; + base = round_down(eofs, vcnt << amortizedshift); + in = m->kaddr + base; + + i = (eofs - base) >> amortizedshift; + + lo = decode_compactedbits(lclusterbits, lomask, + in, encodebits * i, &type); + m->type = type; + if (type == Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD) { + m->clusterofs = 1 << lclusterbits; + + /* figure out lookahead_distance: delta[1] if needed */ + if (lookahead) + m->delta[1] = get_compacted_la_distance(lclusterbits, + encodebits, + vcnt, in, i); + if (lo & Z_EROFS_VLE_DI_D0_CBLKCNT) { + if (!big_pcluster) { + DBG_BUGON(1); + return -EFSCORRUPTED; + } + m->compressedlcs = lo & ~Z_EROFS_VLE_DI_D0_CBLKCNT; + m->delta[0] = 1; + return 0; + } else if (i + 1 != (int)vcnt) { + m->delta[0] = lo; + return 0; + } + /* + * since the last lcluster in the pack is special, + * of which lo saves delta[1] rather than delta[0]. + * Hence, get delta[0] by the previous lcluster indirectly. + */ + lo = decode_compactedbits(lclusterbits, lomask, + in, encodebits * (i - 1), &type); + if (type != Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD) + lo = 0; + else if (lo & Z_EROFS_VLE_DI_D0_CBLKCNT) + lo = 1; + m->delta[0] = lo + 1; + return 0; + } + m->clusterofs = lo; + m->delta[0] = 0; + /* figout out blkaddr (pblk) for HEAD lclusters */ + if (!big_pcluster) { + nblk = 1; + while (i > 0) { + --i; + lo = decode_compactedbits(lclusterbits, lomask, + in, encodebits * i, &type); + if (type == Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD) + i -= lo; + + if (i >= 0) + ++nblk; + } + } else { + nblk = 0; + while (i > 0) { + --i; + lo = decode_compactedbits(lclusterbits, lomask, + in, encodebits * i, &type); + if (type == Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD) { + if (lo & Z_EROFS_VLE_DI_D0_CBLKCNT) { + --i; + nblk += lo & ~Z_EROFS_VLE_DI_D0_CBLKCNT; + continue; + } + if (lo == 1) { + DBG_BUGON(1); + /* --i; ++nblk; continue; */ + return -EFSCORRUPTED; + } + i -= lo - 2; + continue; + } + ++nblk; + } + } + in += (vcnt << amortizedshift) - sizeof(__le32); + m->pblk = le32_to_cpu(*(__le32 *)in) + nblk; + return 0; +} + +static int compacted_load_cluster_from_disk(struct z_erofs_maprecorder *m, + unsigned long lcn, bool lookahead) +{ + struct erofs_inode *const vi = m->inode; + const unsigned int lclusterbits = vi->z_logical_clusterbits; + const erofs_off_t ebase = round_up(iloc(vi->nid) + vi->inode_isize + + vi->xattr_isize, 8) + + sizeof(struct z_erofs_map_header); + const unsigned int totalidx = DIV_ROUND_UP(vi->i_size, EROFS_BLKSIZ); + unsigned int compacted_4b_initial, compacted_2b; + unsigned int amortizedshift; + erofs_off_t pos; + int err; + + if (lclusterbits != 12) + return -EOPNOTSUPP; + + if (lcn >= totalidx) + return -EINVAL; + + m->lcn = lcn; + /* used to align to 32-byte (compacted_2b) alignment */ + compacted_4b_initial = (32 - ebase % 32) / 4; + if (compacted_4b_initial == 32 / 4) + compacted_4b_initial = 0; + + if (vi->z_advise & Z_EROFS_ADVISE_COMPACTED_2B) + compacted_2b = rounddown(totalidx - compacted_4b_initial, 16); + else + compacted_2b = 0; + + pos = ebase; + if (lcn < compacted_4b_initial) { + amortizedshift = 2; + goto out; + } + pos += compacted_4b_initial * 4; + lcn -= compacted_4b_initial; + + if (lcn < compacted_2b) { + amortizedshift = 1; + goto out; + } + pos += compacted_2b * 2; + lcn -= compacted_2b; + amortizedshift = 2; +out: + pos += lcn * (1 << amortizedshift); + err = z_erofs_reload_indexes(m, erofs_blknr(pos)); + if (err) + return err; + return unpack_compacted_index(m, amortizedshift, erofs_blkoff(pos), + lookahead); +} + +static int z_erofs_load_cluster_from_disk(struct z_erofs_maprecorder *m, + unsigned int lcn, bool lookahead) +{ + const unsigned int datamode = m->inode->datalayout; + + if (datamode == EROFS_INODE_FLAT_COMPRESSION_LEGACY) + return legacy_load_cluster_from_disk(m, lcn); + + if (datamode == EROFS_INODE_FLAT_COMPRESSION) + return compacted_load_cluster_from_disk(m, lcn, lookahead); + + return -EINVAL; +} + +static int z_erofs_extent_lookback(struct z_erofs_maprecorder *m, + unsigned int lookback_distance) +{ + struct erofs_inode *const vi = m->inode; + struct erofs_map_blocks *const map = m->map; + const unsigned int lclusterbits = vi->z_logical_clusterbits; + unsigned long lcn = m->lcn; + int err; + + if (lcn < lookback_distance) { + erofs_err("bogus lookback distance @ nid %llu", + (unsigned long long)vi->nid); + DBG_BUGON(1); + return -EFSCORRUPTED; + } + + /* load extent head logical cluster if needed */ + lcn -= lookback_distance; + err = z_erofs_load_cluster_from_disk(m, lcn, false); + if (err) + return err; + + switch (m->type) { + case Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD: + if (!m->delta[0]) { + erofs_err("invalid lookback distance 0 @ nid %llu", + (unsigned long long)vi->nid); + DBG_BUGON(1); + return -EFSCORRUPTED; + } + return z_erofs_extent_lookback(m, m->delta[0]); + case Z_EROFS_VLE_CLUSTER_TYPE_PLAIN: + case Z_EROFS_VLE_CLUSTER_TYPE_HEAD: + m->headtype = m->type; + map->m_la = (lcn << lclusterbits) | m->clusterofs; + break; + default: + erofs_err("unknown type %u @ lcn %lu of nid %llu", + m->type, lcn, (unsigned long long)vi->nid); + DBG_BUGON(1); + return -EOPNOTSUPP; + } + return 0; +} + +static int z_erofs_get_extent_compressedlen(struct z_erofs_maprecorder *m, + unsigned int initial_lcn) +{ + struct erofs_inode *const vi = m->inode; + struct erofs_map_blocks *const map = m->map; + const unsigned int lclusterbits = vi->z_logical_clusterbits; + unsigned long lcn; + int err; + + DBG_BUGON(m->type != Z_EROFS_VLE_CLUSTER_TYPE_PLAIN && + m->type != Z_EROFS_VLE_CLUSTER_TYPE_HEAD); + if (m->headtype == Z_EROFS_VLE_CLUSTER_TYPE_PLAIN || + !(vi->z_advise & Z_EROFS_ADVISE_BIG_PCLUSTER_1)) { + map->m_plen = 1 << lclusterbits; + return 0; + } + + lcn = m->lcn + 1; + if (m->compressedlcs) + goto out; + + err = z_erofs_load_cluster_from_disk(m, lcn, false); + if (err) + return err; + + /* + * If the 1st NONHEAD lcluster has already been handled initially w/o + * valid compressedlcs, which means at least it mustn't be CBLKCNT, or + * an internal implemenatation error is detected. + * + * The following code can also handle it properly anyway, but let's + * BUG_ON in the debugging mode only for developers to notice that. + */ + DBG_BUGON(lcn == initial_lcn && + m->type == Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD); + + switch (m->type) { + case Z_EROFS_VLE_CLUSTER_TYPE_PLAIN: + case Z_EROFS_VLE_CLUSTER_TYPE_HEAD: + /* + * if the 1st NONHEAD lcluster is actually PLAIN or HEAD type + * rather than CBLKCNT, it's a 1 lcluster-sized pcluster. + */ + m->compressedlcs = 1; + break; + case Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD: + if (m->delta[0] != 1) + goto err_bonus_cblkcnt; + if (m->compressedlcs) + break; + /* fallthrough */ + default: + erofs_err("cannot found CBLKCNT @ lcn %lu of nid %llu", + lcn, vi->nid | 0ULL); + DBG_BUGON(1); + return -EFSCORRUPTED; + } +out: + map->m_plen = m->compressedlcs << lclusterbits; + return 0; +err_bonus_cblkcnt: + erofs_err("bogus CBLKCNT @ lcn %lu of nid %llu", + lcn, vi->nid | 0ULL); + DBG_BUGON(1); + return -EFSCORRUPTED; +} + +static int z_erofs_get_extent_decompressedlen(struct z_erofs_maprecorder *m) +{ + struct erofs_inode *const vi = m->inode; + struct erofs_map_blocks *map = m->map; + unsigned int lclusterbits = vi->z_logical_clusterbits; + u64 lcn = m->lcn, headlcn = map->m_la >> lclusterbits; + int err; + + do { + /* handle the last EOF pcluster (no next HEAD lcluster) */ + if ((lcn << lclusterbits) >= vi->i_size) { + map->m_llen = vi->i_size - map->m_la; + return 0; + } + + err = z_erofs_load_cluster_from_disk(m, lcn, true); + if (err) + return err; + + if (m->type == Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD) { + DBG_BUGON(!m->delta[1] && + m->clusterofs != 1 << lclusterbits); + } else if (m->type == Z_EROFS_VLE_CLUSTER_TYPE_PLAIN || + m->type == Z_EROFS_VLE_CLUSTER_TYPE_HEAD) { + /* go on until the next HEAD lcluster */ + if (lcn != headlcn) + break; + m->delta[1] = 1; + } else { + erofs_err("unknown type %u @ lcn %llu of nid %llu", + m->type, lcn | 0ULL, + (unsigned long long)vi->nid); + DBG_BUGON(1); + return -EOPNOTSUPP; + } + lcn += m->delta[1]; + } while (m->delta[1]); + + map->m_llen = (lcn << lclusterbits) + m->clusterofs - map->m_la; + return 0; +} + +int z_erofs_map_blocks_iter(struct erofs_inode *vi, + struct erofs_map_blocks *map, + int flags) +{ + struct z_erofs_maprecorder m = { + .inode = vi, + .map = map, + .kaddr = map->mpage, + }; + int err = 0; + unsigned int lclusterbits, endoff; + unsigned long initial_lcn; + unsigned long long ofs, end; + + /* when trying to read beyond EOF, leave it unmapped */ + if (map->m_la >= vi->i_size) { + map->m_llen = map->m_la + 1 - vi->i_size; + map->m_la = vi->i_size; + map->m_flags = 0; + goto out; + } + + err = z_erofs_fill_inode_lazy(vi); + if (err) + goto out; + + lclusterbits = vi->z_logical_clusterbits; + ofs = map->m_la; + initial_lcn = ofs >> lclusterbits; + endoff = ofs & ((1 << lclusterbits) - 1); + + err = z_erofs_load_cluster_from_disk(&m, initial_lcn, false); + if (err) + goto out; + + map->m_flags = EROFS_MAP_MAPPED | EROFS_MAP_ENCODED; + end = (m.lcn + 1ULL) << lclusterbits; + switch (m.type) { + case Z_EROFS_VLE_CLUSTER_TYPE_PLAIN: + case Z_EROFS_VLE_CLUSTER_TYPE_HEAD: + if (endoff >= m.clusterofs) { + m.headtype = m.type; + map->m_la = (m.lcn << lclusterbits) | m.clusterofs; + break; + } + /* m.lcn should be >= 1 if endoff < m.clusterofs */ + if (!m.lcn) { + erofs_err("invalid logical cluster 0 at nid %llu", + (unsigned long long)vi->nid); + err = -EFSCORRUPTED; + goto out; + } + end = (m.lcn << lclusterbits) | m.clusterofs; + map->m_flags |= EROFS_MAP_FULL_MAPPED; + m.delta[0] = 1; + /* fallthrough */ + case Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD: + /* get the correspoinding first chunk */ + err = z_erofs_extent_lookback(&m, m.delta[0]); + if (err) + goto out; + break; + default: + erofs_err("unknown type %u @ offset %llu of nid %llu", + m.type, ofs, (unsigned long long)vi->nid); + err = -EOPNOTSUPP; + goto out; + } + + map->m_llen = end - map->m_la; + map->m_pa = blknr_to_addr(m.pblk); + + err = z_erofs_get_extent_compressedlen(&m, initial_lcn); + if (err) + goto out; + + if (m.headtype == Z_EROFS_VLE_CLUSTER_TYPE_PLAIN) + map->m_algorithmformat = Z_EROFS_COMPRESSION_SHIFTED; + else + map->m_algorithmformat = vi->z_algorithmtype[0]; + + if (flags & EROFS_GET_BLOCKS_FIEMAP) { + err = z_erofs_get_extent_decompressedlen(&m); + if (!err) + map->m_flags |= EROFS_MAP_FULL_MAPPED; + } + +out: + erofs_dbg("m_la %" PRIu64 " m_pa %" PRIu64 " m_llen %" PRIu64 " m_plen %" PRIu64 " m_flags 0%o", + map->m_la, map->m_pa, + map->m_llen, map->m_plen, map->m_flags); + + DBG_BUGON(err < 0 && err != -ENOMEM); + return err; +} -- cgit v1.1