[RFCv3] erofs-utils: on-disk extent format for blocks
Pratik Shinde
pratikshinde320 at gmail.com
Thu Jan 2 20:47:32 AEDT 2020
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 ?
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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