Scan holes for chunk-based inodes if either --chunksize=# or -Ededupe (without compression) is specified so that sparse files can be made, which has already been supported since Linux 5.15.
Signed-off-by: Gao Xiang <[email protected]> --- lib/blobchunk.c | 71 ++++++++++++++++++++++++++++++++++++++----------- 1 file changed, 55 insertions(+), 16 deletions(-) diff --git a/lib/blobchunk.c b/lib/blobchunk.c index 77b0c17..55ea061 100644 --- a/lib/blobchunk.c +++ b/lib/blobchunk.c @@ -18,7 +18,7 @@ void erofs_sha256(const unsigned char *in, unsigned long in_size, struct erofs_blobchunk { struct hashmap_entry ent; char sha256[32]; - unsigned int chunksize; + erofs_off_t chunksize; erofs_blk_t blkaddr; }; @@ -27,9 +27,12 @@ static FILE *blobfile; static erofs_blk_t remapped_base; static bool multidev; static struct erofs_buffer_head *bh_devt; +struct erofs_blobchunk erofs_holechunk = { + .blkaddr = EROFS_NULL_ADDR, +}; static struct erofs_blobchunk *erofs_blob_getchunk(int fd, - unsigned int chunksize) + erofs_off_t chunksize) { static u8 zeroed[EROFS_BLKSIZ]; u8 *chunkdata, sha256[32]; @@ -129,7 +132,11 @@ int erofs_blob_write_chunk_indexes(struct erofs_inode *inode, chunk = *(void **)(inode->chunkindexes + src); - idx.blkaddr = base_blkaddr + chunk->blkaddr; + if (chunk->blkaddr != EROFS_NULL_ADDR) + idx.blkaddr = base_blkaddr + chunk->blkaddr; + else + idx.blkaddr = EROFS_NULL_ADDR; + if (extent_start != EROFS_NULL_ADDR && idx.blkaddr == extent_end + 1) { extent_end = idx.blkaddr; @@ -163,14 +170,28 @@ int erofs_blob_write_chunk_indexes(struct erofs_inode *inode, int erofs_blob_write_chunked_file(struct erofs_inode *inode) { - unsigned int chunksize = 1 << cfg.c_chunkbits; - unsigned int count = DIV_ROUND_UP(inode->i_size, chunksize); + unsigned int chunkbits = cfg.c_chunkbits; + unsigned int count, unit; struct erofs_inode_chunk_index *idx; - erofs_off_t pos, len; - unsigned int unit; + erofs_off_t pos, len, chunksize; int fd, ret; - inode->u.chunkformat |= inode->u.chunkbits - LOG_BLOCK_SIZE; + fd = open(inode->i_srcpath, O_RDONLY | O_BINARY); + if (fd < 0) + return -errno; +#ifdef SEEK_DATA + /* if the file is fully sparsed, use one big chunk instead */ + if (lseek(fd, 0, SEEK_DATA) < 0 && errno == ENXIO) { + chunkbits = ilog2(inode->i_size - 1) + 1; + if (chunkbits < LOG_BLOCK_SIZE) + chunkbits = LOG_BLOCK_SIZE; + } +#endif + if (chunkbits - LOG_BLOCK_SIZE > EROFS_CHUNK_FORMAT_BLKBITS_MASK) + chunkbits = EROFS_CHUNK_FORMAT_BLKBITS_MASK + LOG_BLOCK_SIZE; + chunksize = 1ULL << chunkbits; + count = DIV_ROUND_UP(inode->i_size, chunksize); + inode->u.chunkformat |= chunkbits - LOG_BLOCK_SIZE; if (multidev) inode->u.chunkformat |= EROFS_CHUNK_FORMAT_INDEXES; @@ -181,24 +202,41 @@ int erofs_blob_write_chunked_file(struct erofs_inode *inode) inode->extent_isize = count * unit; idx = malloc(count * max(sizeof(*idx), sizeof(void *))); - if (!idx) + if (!idx) { + close(fd); return -ENOMEM; - inode->chunkindexes = idx; - - fd = open(inode->i_srcpath, O_RDONLY | O_BINARY); - if (fd < 0) { - ret = -errno; - goto err; } + inode->chunkindexes = idx; for (pos = 0; pos < inode->i_size; pos += len) { struct erofs_blobchunk *chunk; +#ifdef SEEK_DATA + off64_t offset = lseek(fd, pos, SEEK_DATA); + + if (offset < 0) { + if (errno != ENXIO) + offset = pos; + else + offset = ((pos >> chunkbits) + 1) << chunkbits; + } else { + offset &= ~(chunksize - 1); + } + + if (offset > pos) { + len = 0; + do { + *(void **)idx++ = &erofs_holechunk; + pos += chunksize; + } while (pos < offset); + DBG_BUGON(pos != offset); + continue; + } +#endif len = min_t(u64, inode->i_size - pos, chunksize); chunk = erofs_blob_getchunk(fd, len); if (IS_ERR(chunk)) { ret = PTR_ERR(chunk); - close(fd); goto err; } *(void **)idx++ = chunk; @@ -207,6 +245,7 @@ int erofs_blob_write_chunked_file(struct erofs_inode *inode) close(fd); return 0; err: + close(fd); free(inode->chunkindexes); inode->chunkindexes = NULL; return ret; -- 2.24.4
