diff options
Diffstat (limited to 'fs/erofs/data.c')
| -rw-r--r-- | fs/erofs/data.c | 223 |
1 files changed, 223 insertions, 0 deletions
diff --git a/fs/erofs/data.c b/fs/erofs/data.c new file mode 100644 index 0000000000..699975c1be --- /dev/null +++ b/fs/erofs/data.c @@ -0,0 +1,223 @@ +// SPDX-License-Identifier: GPL-2.0+ +#include "internal.h" + +static int erofs_map_blocks_flatmode(struct erofs_inode *inode, + struct erofs_map_blocks *map, + int flags) +{ + int err = 0; + erofs_blk_t nblocks, lastblk; + u64 offset = map->m_la; + struct erofs_inode *vi = inode; + bool tailendpacking = (vi->datalayout == EROFS_INODE_FLAT_INLINE); + + nblocks = DIV_ROUND_UP(inode->i_size, EROFS_BLKSIZ); + lastblk = nblocks - tailendpacking; + + /* there is no hole in flatmode */ + map->m_flags = EROFS_MAP_MAPPED; + + if (offset < blknr_to_addr(lastblk)) { + map->m_pa = blknr_to_addr(vi->u.i_blkaddr) + map->m_la; + map->m_plen = blknr_to_addr(lastblk) - offset; + } else if (tailendpacking) { + /* 2 - inode inline B: inode, [xattrs], inline last blk... */ + map->m_pa = iloc(vi->nid) + vi->inode_isize + + vi->xattr_isize + erofs_blkoff(map->m_la); + map->m_plen = inode->i_size - offset; + + /* inline data should be located in one meta block */ + if (erofs_blkoff(map->m_pa) + map->m_plen > PAGE_SIZE) { + erofs_err("inline data cross block boundary @ nid %" PRIu64, + vi->nid); + DBG_BUGON(1); + err = -EFSCORRUPTED; + goto err_out; + } + + map->m_flags |= EROFS_MAP_META; + } else { + erofs_err("internal error @ nid: %" PRIu64 " (size %llu), m_la 0x%" PRIx64, + vi->nid, (unsigned long long)inode->i_size, map->m_la); + DBG_BUGON(1); + err = -EIO; + goto err_out; + } + + map->m_llen = map->m_plen; +err_out: + return err; +} + +int erofs_map_blocks(struct erofs_inode *inode, + struct erofs_map_blocks *map, int flags) +{ + struct erofs_inode *vi = inode; + struct erofs_inode_chunk_index *idx; + u8 buf[EROFS_BLKSIZ]; + u64 chunknr; + unsigned int unit; + erofs_off_t pos; + int err = 0; + + map->m_deviceid = 0; + if (map->m_la >= inode->i_size) { + /* leave out-of-bound access unmapped */ + map->m_flags = 0; + map->m_plen = 0; + goto out; + } + + if (vi->datalayout != EROFS_INODE_CHUNK_BASED) + return erofs_map_blocks_flatmode(inode, map, flags); + + if (vi->u.chunkformat & EROFS_CHUNK_FORMAT_INDEXES) + unit = sizeof(*idx); /* chunk index */ + else + unit = EROFS_BLOCK_MAP_ENTRY_SIZE; /* block map */ + + chunknr = map->m_la >> vi->u.chunkbits; + pos = roundup(iloc(vi->nid) + vi->inode_isize + + vi->xattr_isize, unit) + unit * chunknr; + + err = erofs_blk_read(buf, erofs_blknr(pos), 1); + if (err < 0) + return -EIO; + + map->m_la = chunknr << vi->u.chunkbits; + map->m_plen = min_t(erofs_off_t, 1UL << vi->u.chunkbits, + roundup(inode->i_size - map->m_la, EROFS_BLKSIZ)); + + /* handle block map */ + if (!(vi->u.chunkformat & EROFS_CHUNK_FORMAT_INDEXES)) { + __le32 *blkaddr = (void *)buf + erofs_blkoff(pos); + + if (le32_to_cpu(*blkaddr) == EROFS_NULL_ADDR) { + map->m_flags = 0; + } else { + map->m_pa = blknr_to_addr(le32_to_cpu(*blkaddr)); + map->m_flags = EROFS_MAP_MAPPED; + } + goto out; + } + /* parse chunk indexes */ + idx = (void *)buf + erofs_blkoff(pos); + switch (le32_to_cpu(idx->blkaddr)) { + case EROFS_NULL_ADDR: + map->m_flags = 0; + break; + default: + map->m_deviceid = le16_to_cpu(idx->device_id) & + sbi.device_id_mask; + map->m_pa = blknr_to_addr(le32_to_cpu(idx->blkaddr)); + map->m_flags = EROFS_MAP_MAPPED; + break; + } +out: + map->m_llen = map->m_plen; + return err; +} + +int erofs_map_dev(struct erofs_sb_info *sbi, struct erofs_map_dev *map) +{ + struct erofs_device_info *dif; + int id; + + if (map->m_deviceid) { + if (sbi->extra_devices < map->m_deviceid) + return -ENODEV; + } else if (sbi->extra_devices) { + for (id = 0; id < sbi->extra_devices; ++id) { + erofs_off_t startoff, length; + + dif = sbi->devs + id; + if (!dif->mapped_blkaddr) + continue; + startoff = blknr_to_addr(dif->mapped_blkaddr); + length = blknr_to_addr(dif->blocks); + + if (map->m_pa >= startoff && + map->m_pa < startoff + length) { + map->m_pa -= startoff; + break; + } + } + } + return 0; +} + +static int erofs_read_raw_data(struct erofs_inode *inode, char *buffer, + erofs_off_t size, erofs_off_t offset) +{ + struct erofs_map_blocks map = { + .index = UINT_MAX, + }; + struct erofs_map_dev mdev; + int ret; + erofs_off_t ptr = offset; + + while (ptr < offset + size) { + char *const estart = buffer + ptr - offset; + erofs_off_t eend; + + map.m_la = ptr; + ret = erofs_map_blocks(inode, &map, 0); + if (ret) + return ret; + + DBG_BUGON(map.m_plen != map.m_llen); + + mdev = (struct erofs_map_dev) { + .m_deviceid = map.m_deviceid, + .m_pa = map.m_pa, + }; + ret = erofs_map_dev(&sbi, &mdev); + if (ret) + return ret; + + /* trim extent */ + eend = min(offset + size, map.m_la + map.m_llen); + DBG_BUGON(ptr < map.m_la); + + if (!(map.m_flags & EROFS_MAP_MAPPED)) { + if (!map.m_llen) { + /* reached EOF */ + memset(estart, 0, offset + size - ptr); + ptr = offset + size; + continue; + } + memset(estart, 0, eend - ptr); + ptr = eend; + continue; + } + + if (ptr > map.m_la) { + mdev.m_pa += ptr - map.m_la; + map.m_la = ptr; + } + + ret = erofs_dev_read(mdev.m_deviceid, estart, mdev.m_pa, + eend - map.m_la); + if (ret < 0) + return -EIO; + ptr = eend; + } + return 0; +} + +int erofs_pread(struct erofs_inode *inode, char *buf, + erofs_off_t count, erofs_off_t offset) +{ + switch (inode->datalayout) { + case EROFS_INODE_FLAT_PLAIN: + case EROFS_INODE_FLAT_INLINE: + case EROFS_INODE_CHUNK_BASED: + return erofs_read_raw_data(inode, buf, count, offset); + case EROFS_INODE_FLAT_COMPRESSION_LEGACY: + case EROFS_INODE_FLAT_COMPRESSION: + return -EOPNOTSUPP; + default: + break; + } + return -EINVAL; +} |