Gao, Okay, I will rename the 'size' variables accordingly. The 'S_SHIFT' gives the logical block number inside file. I am using it to assign logical block no. to extents. Also, I will modify the code to record only data extents. --Pratik. On Sun, Dec 29, 2019 at 8:26 AM Gao Xiang wrote: > Hi Pratik, > > On Fri, Dec 27, 2019 at 09:13:48PM +0530, Pratik Shinde wrote: > > since this patch is quite different from previous patches I am treating > > this as new patch. > > > > 1) On disk extent format for erofs data blocks. > > 2) Detect holes inside files & skip allocation for hole blocks. > > > > Signed-off-by: Pratik Shinde > > --- > > include/erofs/internal.h | 21 ++++++- > > lib/inode.c | 155 > +++++++++++++++++++++++++++++++++++++++++------ > > 2 files changed, 156 insertions(+), 20 deletions(-) > > > > diff --git a/include/erofs/internal.h b/include/erofs/internal.h > > index e13adda..128aa63 100644 > > --- a/include/erofs/internal.h > > +++ b/include/erofs/internal.h > > @@ -63,7 +63,7 @@ struct erofs_sb_info { > > extern struct erofs_sb_info sbi; > > > > struct erofs_inode { > > - struct list_head i_hash, i_subdirs, i_xattrs; > > + struct list_head i_hash, i_subdirs, i_xattrs, i_extents; > > > > unsigned int i_count; > > struct erofs_inode *i_parent; > > @@ -93,6 +93,7 @@ struct erofs_inode { > > > > unsigned int xattr_isize; > > unsigned int extent_isize; > > + unsigned int extent_meta_isize; > > maybe sparse_extent_isize is better... > > p.s. maybe we could send another patch rename extent_isize to > compress_extent_isize or some better name... > > > > > erofs_nid_t nid; > > struct erofs_buffer_head *bh; > > @@ -139,5 +140,23 @@ static inline const char *erofs_strerror(int err) > > return msg; > > } > > > > +#define HOLE_BLK -1 > > +/* on disk extent format */ > > +struct erofs_extent { > > + __le32 ee_lblk; > > + __le32 ee_pblk; > > + __le32 ee_len; > > +}; > > + > > +struct erofs_extent_node { > > + struct list_head next; > > + erofs_blk_t lblk; > > + erofs_blk_t pblk; > > + u32 len; > > +}; > > + > > +struct erofs_inline_extent_header { > > + u32 count; > > +}; > > #endif > > > > diff --git a/lib/inode.c b/lib/inode.c > > index 0e19b11..a6af509 100644 > > --- a/lib/inode.c > > +++ b/lib/inode.c > > @@ -38,6 +38,99 @@ static unsigned char erofs_type_by_mode[S_IFMT >> > S_SHIFT] = { > > > > struct list_head inode_hashtable[NR_INODE_HASHTABLE]; > > > > + > > +#define IS_HOLE(start, end) (roundup(start, EROFS_BLKSIZ) == start && > \ > > + roundup(end, EROFS_BLKSIZ) == end && \ > > + (end - start) % EROFS_BLKSIZ == 0) > > See below.. > > > + > > +/* returns the number of holes present in the file */ > > +unsigned int erofs_read_extents(struct erofs_inode *inode, > > + struct list_head *extents) > > +{ > > + int fd, st, en, dt; > > + unsigned int nholes = 0; > > + erofs_off_t data, hole, len, last_data; > > + struct erofs_extent_node *e_hole, *e_data; > > + > > + fd = open(inode->i_srcpath, O_RDONLY); > > + if (fd < 0) { > > + return -errno; > > + } > > + len = lseek(fd, 0, SEEK_END); > > + if (lseek(fd, 0, SEEK_SET) == -1) > > + return -errno; > > + data = 0; > > + last_data = 0; > > + while (data < len) { > > + hole = lseek(fd, data, SEEK_HOLE); > > + if (hole == len) > > + break; > > + data = lseek(fd, hole, SEEK_DATA); > > + if (data < 0 || hole > data) { > > + return -EINVAL; > > + } > > + if (IS_HOLE(hole, data)) { > > + st = hole >> S_SHIFT; > > + en = data >> S_SHIFT; > > + dt = last_data >> S_SHIFT; > > Why using S_SHIFT here, some special meaning? > > > + last_data = data; > > + e_data = malloc(sizeof(struct erofs_extent_node)); > > + if (e_data == NULL) > > + return -ENOMEM; > > + e_data->lblk = dt; > > + e_data->len = (st - dt); > > + list_add_tail(&e_data->next, extents); > > + e_hole = malloc(sizeof(struct erofs_extent_node)); > > + if (e_hole == NULL) > > + return -ENOMEM; > > + e_hole->lblk = st; > > + e_hole->pblk = HOLE_BLK; > > + e_hole->len = (en - st); > > + list_add_tail(&e_hole->next, extents); > > + nholes += e_hole->len; > > Maybe we don't need to emit all HOLK extents since all data extents > are with _length_... It is easy to detect all holes between extents... > > If some block doesn't belong to any extent, it's a hole. > > Thanks, > Gao Xiang > > > + } > > + } > > + /* rounddown to exclude tail-end data */ > > + if (last_data < len && (len - last_data) >= EROFS_BLKSIZ) { > > + e_data = malloc(sizeof(struct erofs_extent_node)); > > + if (e_data == NULL) > > + return -ENOMEM; > > + st = last_data >> S_SHIFT; > > + e_data->lblk = st; > > + e_data->len = rounddown((len - last_data), EROFS_BLKSIZ) > >> S_SHIFT; > > + list_add_tail(&e_data->next, extents); > > + } > > + return nholes; > > +} > > + > > +char *erofs_create_extent_buffer(struct list_head *extents, unsigned > int size) > > +{ > > + struct erofs_extent_node *e_node; > > + struct erofs_inline_extent_header *header; > > + char *buf; > > + unsigned int p = 0; > > + > > + buf = malloc(size); > > + if (buf == NULL) > > + return ERR_PTR(-ENOMEM); > > + header = (struct erofs_inline_extent_header *) buf; > > + header->count = 0; > > + p += sizeof(struct erofs_inline_extent_header); > > + list_for_each_entry(e_node, extents, next) { > > + const struct erofs_extent ee = { > > + .ee_lblk = cpu_to_le32(e_node->lblk), > > + .ee_pblk = cpu_to_le32(e_node->pblk), > > + .ee_len = cpu_to_le32(e_node->len) > > + }; > > + memcpy(buf + p, &ee, sizeof(struct erofs_extent)); > > + p += sizeof(struct erofs_extent); > > + header->count++; > > + list_del(&e_node->next); > > + free(e_node); > > + } > > + return buf; > > +} > > + > > void erofs_inode_manager_init(void) > > { > > unsigned int i; > > @@ -304,8 +397,9 @@ static bool erofs_file_is_compressible(struct > erofs_inode *inode) > > > > int erofs_write_file(struct erofs_inode *inode) > > { > > - unsigned int nblocks, i; > > + unsigned int nblocks, i, j, nholes; > > int ret, fd; > > + struct erofs_extent_node *e_node; > > > > if (!inode->i_size) { > > inode->datalayout = EROFS_INODE_FLAT_PLAIN; > > @@ -322,31 +416,43 @@ int erofs_write_file(struct erofs_inode *inode) > > /* fallback to all data uncompressed */ > > inode->datalayout = EROFS_INODE_FLAT_INLINE; > > nblocks = inode->i_size / EROFS_BLKSIZ; > > - > > - ret = __allocate_inode_bh_data(inode, nblocks); > > + nholes = erofs_read_extents(inode, &inode->i_extents); > > + if (nholes < 0) > > + return nholes; > > + if (nblocks < 0) > > + return nblocks; > > + ret = __allocate_inode_bh_data(inode, nblocks - nholes); > > if (ret) > > return ret; > > > > fd = open(inode->i_srcpath, O_RDONLY | O_BINARY); > > if (fd < 0) > > return -errno; > > - > > - for (i = 0; i < nblocks; ++i) { > > - char buf[EROFS_BLKSIZ]; > > - > > - ret = read(fd, buf, EROFS_BLKSIZ); > > - if (ret != EROFS_BLKSIZ) { > > - if (ret < 0) > > - goto fail; > > - close(fd); > > - return -EAGAIN; > > + i = inode->u.i_blkaddr; > > + inode->extent_meta_isize = sizeof(struct > erofs_inline_extent_header); > > + list_for_each_entry(e_node, &inode->i_extents, next) { > > + inode->extent_meta_isize += sizeof(struct erofs_extent); > > + if (e_node->pblk == HOLE_BLK) { > > + lseek(fd, e_node->len * EROFS_BLKSIZ, SEEK_CUR); > > + continue; > > } > > + e_node->pblk = i; > > + i += e_node->len; > > + for (j = 0; j < e_node->len; j++) { > > + char buf[EROFS_BLKSIZ]; > > + ret = read(fd, buf, EROFS_BLKSIZ); > > + if (ret != EROFS_BLKSIZ) { > > + if (ret < 0) > > + goto fail; > > + close(fd); > > + return -EAGAIN; > > + } > > + ret = blk_write(buf, e_node->pblk + j, 1); > > + if (ret) > > + goto fail; > > > > - ret = blk_write(buf, inode->u.i_blkaddr + i, 1); > > - if (ret) > > - goto fail; > > + } > > } > > - > > /* read the tail-end data */ > > inode->idata_size = inode->i_size % EROFS_BLKSIZ; > > if (inode->idata_size) { > > @@ -479,8 +585,19 @@ static bool erofs_bh_flush_write_inode(struct > erofs_buffer_head *bh) > > if (ret) > > return false; > > free(inode->compressmeta); > > + off += inode->extent_isize; > > } > > > > + if (inode->extent_meta_isize) { > > + char *extents = > erofs_create_extent_buffer(&inode->i_extents, > > + > inode->extent_meta_isize); > > + if (IS_ERR(extents)) > > + return false; > > + ret = dev_write(extents, off, inode->extent_meta_isize); > > + free(extents); > > + if (ret) > > + return false; > > + } > > inode->bh = NULL; > > erofs_iput(inode); > > return erofs_bh_flush_generic_end(bh); > > @@ -737,10 +854,11 @@ struct erofs_inode *erofs_new_inode(void) > > > > init_list_head(&inode->i_subdirs); > > init_list_head(&inode->i_xattrs); > > + init_list_head(&inode->i_extents); > > > > inode->idata_size = 0; > > inode->xattr_isize = 0; > > - inode->extent_isize = 0; > > + inode->extent_meta_isize = 0; > > > > inode->bh = inode->bh_inline = inode->bh_data = NULL; > > inode->idata = NULL; > > @@ -961,4 +1079,3 @@ struct erofs_inode > *erofs_mkfs_build_tree_from_path(struct erofs_inode *parent, > > > > return erofs_mkfs_build_tree(inode); > > } > > - > > -- > > 2.9.3 > > >