[RFCv3] erofs-utils: on-disk extent format for blocks
Pratik Shinde
pratikshinde320 at gmail.com
Thu Jan 2 22:02:34 AEDT 2020
Hi Gao,
You are correct. The macro logic can be simplified. I will do that.
I will work on the kernel part of this change & do some testing on it.
I will keep you posted about the change and relevant tests I am running on
it.
--Pratik.
On Thu, Jan 2, 2020, 4:17 PM Gao Xiang <gaoxiang25 at huawei.com> wrote:
> Hi Pratik,
>
> On Thu, Jan 02, 2020 at 03:17:32PM +0530, Pratik Shinde wrote:
> > 1)Moved on-disk structures to erofs_fs.h
> > 2)Some naming changes.
> >
> > I think we can keep 'IS_HOLE()' macro, otherwise the code
> > does not look clean(if used directly/without macro).Its getting
> > used only in inode.c so it can be kept there.
> > what do you think ?
>
> What I'm little concerned is the relationship between
> the name of IS_HOLE and its implementation...
>
> In other words, why
> roundup(start, EROFS_BLKSIZ) == start &&
> roundup(end, EROFS_BLKSIZ) == end &&
> (end - start) % EROFS_BLKSIZ == 0
> should be an erofs hole...
>
> But that is minor, I reserve my opinion on this for now...
>
> This patch generally looks good to me, yet I haven't
> played with it till now.
>
> Could you implement a workable RFC patch for kernel side
> as well? Since I'm still busying in XZ library and other
> convert patches for 5.6...
>
> I'd like to hear if some other opinions from Chao and Guifu.
> Since it enhances the on-disk format, we need to think it
> over (especially its future expandability).
>
>
> To Chao and Guifu,
> Could you have some extra time looking at this stuff as well?
>
>
> Thanks,
> Gao Xiang
>
> >
> > Signed-off-by: Pratik Shinde <pratikshinde320 at gmail.com>
> > ---
> > include/erofs/internal.h | 9 ++-
> > include/erofs_fs.h | 11 ++++
> > lib/inode.c | 153
> ++++++++++++++++++++++++++++++++++++++++-------
> > 3 files changed, 150 insertions(+), 23 deletions(-)
> >
> > diff --git a/include/erofs/internal.h b/include/erofs/internal.h
> > index e13adda..2d7466b 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_sparse_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 sparse_extent_isize;
> >
> > erofs_nid_t nid;
> > struct erofs_buffer_head *bh;
> > @@ -139,5 +140,11 @@ static inline const char *erofs_strerror(int err)
> > return msg;
> > }
> >
> > +struct erofs_sparse_extent_node {
> > + struct list_head next;
> > + erofs_blk_t lblk;
> > + erofs_blk_t pblk;
> > + u32 len;
> > +};
> > #endif
> >
> > diff --git a/include/erofs_fs.h b/include/erofs_fs.h
> > index bcc4f0c..a63e1c6 100644
> > --- a/include/erofs_fs.h
> > +++ b/include/erofs_fs.h
> > @@ -321,5 +321,16 @@ static inline void
> erofs_check_ondisk_layout_definitions(void)
> > Z_EROFS_VLE_CLUSTER_TYPE_MAX - 1);
> > }
> >
> > +/* on-disk sparse extent format */
> > +struct erofs_sparse_extent {
> > + __le32 ee_lblk;
> > + __le32 ee_pblk;
> > + __le32 ee_len;
> > +};
> > +
> > +struct erofs_sparse_extent_iheader {
> > + u32 count;
> > +};
> > +
> > #endif
> >
> > diff --git a/lib/inode.c b/lib/inode.c
> > index 0e19b11..da20599 100644
> > --- a/lib/inode.c
> > +++ b/lib/inode.c
> > @@ -38,6 +38,97 @@ 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)
> > +
> > +/**
> > + read extents of the given file.
> > + record the data extents and link them into a chain.
> > + exclude holes present in file.
> > + */
> > +unsigned int erofs_read_sparse_extents(int fd, struct list_head
> *extents)
> > +{
> > + erofs_blk_t startblk, endblk, datablk;
> > + unsigned int nholes = 0;
> > + erofs_off_t data, hole, len = 0, last_data;
> > + struct erofs_sparse_extent_node *e_data;
> > +
> > + len = lseek(fd, 0, SEEK_END);
> > + if (len < 0)
> > + return -errno;
> > + 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)) {
> > + startblk = erofs_blknr(hole);
> > + datablk = erofs_blknr(last_data);
> > + endblk = erofs_blknr(data);
> > + last_data = data;
> > + e_data = malloc(sizeof(
> > + struct erofs_sparse_extent_node));
> > + if (e_data == NULL)
> > + return -ENOMEM;
> > + e_data->lblk = datablk;
> > + e_data->len = (startblk - datablk);
> > + list_add_tail(&e_data->next, extents);
> > + nholes += (endblk - startblk);
> > + }
> > + }
> > + /* rounddown to exclude tail-end data */
> > + if (last_data < len && (len - last_data) >= EROFS_BLKSIZ) {
> > + e_data = malloc(sizeof(struct erofs_sparse_extent_node));
> > + if (e_data == NULL)
> > + return -ENOMEM;
> > + startblk = erofs_blknr(last_data);
> > + e_data->lblk = startblk;
> > + e_data->len = erofs_blknr(rounddown((len - last_data),
> > + EROFS_BLKSIZ));
> > + list_add_tail(&e_data->next, extents);
> > + }
> > + return nholes;
> > +}
> > +
> > +int erofs_write_sparse_extents(struct erofs_inode *inode, erofs_off_t
> off)
> > +{
> > + struct erofs_sparse_extent_node *e_node;
> > + struct erofs_sparse_extent_iheader *header;
> > + char *buf;
> > + unsigned int p = 0;
> > + int ret;
> > +
> > + buf = malloc(inode->sparse_extent_isize);
> > + if (buf == NULL)
> > + return -ENOMEM;
> > + header = (struct erofs_sparse_extent_iheader *) buf;
> > + header->count = 0;
> > + p += sizeof(struct erofs_sparse_extent_iheader);
> > + list_for_each_entry(e_node, &inode->i_sparse_extents, next) {
> > + const struct erofs_sparse_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_sparse_extent));
> > + p += sizeof(struct erofs_sparse_extent);
> > + header->count++;
> > + list_del(&e_node->next);
> > + free(e_node);
> > + }
> > + ret = dev_write(buf, off, inode->sparse_extent_isize);
> > + free(buf);
> > + return ret;
> > +}
> > +
> > void erofs_inode_manager_init(void)
> > {
> > unsigned int i;
> > @@ -304,8 +395,9 @@ 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_sparse_extent_node *e_node;
> >
> > if (!inode->i_size) {
> > inode->datalayout = EROFS_INODE_FLAT_PLAIN;
> > @@ -322,31 +414,42 @@ 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);
> > - 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)
> > + nholes = erofs_read_sparse_extents(fd, &inode->i_sparse_extents);
> > + if (nholes < 0) {
> > + close(fd);
> > + return nholes;
> > + }
> > + ret = __allocate_inode_bh_data(inode, nblocks - nholes);
> > + if (ret) {
> > + close(fd);
> > + return ret;
> > + }
> > + i = inode->u.i_blkaddr;
> > + inode->sparse_extent_isize = sizeof(struct
> erofs_sparse_extent_iheader);
> > + list_for_each_entry(e_node, &inode->i_sparse_extents, next) {
> > + inode->sparse_extent_isize += sizeof(struct
> erofs_sparse_extent);
> > + e_node->pblk = i;
> > + ret = lseek(fd, blknr_to_addr(e_node->lblk), SEEK_SET);
> > + if (ret < 0)
> > + goto fail;
> > + 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;
> > - close(fd);
> > - return -EAGAIN;
> > }
> > -
> > - ret = blk_write(buf, inode->u.i_blkaddr + i, 1);
> > - if (ret)
> > - goto fail;
> > + i += e_node->len;
> > }
> > -
> > /* read the tail-end data */
> > inode->idata_size = inode->i_size % EROFS_BLKSIZ;
> > if (inode->idata_size) {
> > @@ -479,8 +582,14 @@ 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->sparse_extent_isize) {
> > + ret = erofs_write_sparse_extents(inode, off);
> > + if (ret)
> > + return false;
> > + }
> > inode->bh = NULL;
> > erofs_iput(inode);
> > return erofs_bh_flush_generic_end(bh);
> > @@ -737,10 +846,11 @@ struct erofs_inode *erofs_new_inode(void)
> >
> > init_list_head(&inode->i_subdirs);
> > init_list_head(&inode->i_xattrs);
> > + init_list_head(&inode->i_sparse_extents);
> >
> > inode->idata_size = 0;
> > inode->xattr_isize = 0;
> > - inode->extent_isize = 0;
> > + inode->sparse_extent_isize = 0;
> >
> > inode->bh = inode->bh_inline = inode->bh_data = NULL;
> > inode->idata = NULL;
> > @@ -961,4 +1071,3 @@ struct erofs_inode
> *erofs_mkfs_build_tree_from_path(struct erofs_inode *parent,
> >
> > return erofs_mkfs_build_tree(inode);
> > }
> > -
> > --
> > 2.9.3
> >
>
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