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authorDavid Oberhollenzer <david.oberhollenzer@sigma-star.at>2019-06-28 12:41:26 +0200
committerDavid Oberhollenzer <david.oberhollenzer@sigma-star.at>2019-06-28 15:07:34 +0200
commit4e017928c7b5b590d2c7e04e42cb497eb3a4f8cf (patch)
tree28f649af1074ab74576a9a715991c610b210f1c0 /lib/sqfs/write_inode.c
parentd89d7e3d7f5b21fe53ea0cbf65134bdc3df30950 (diff)
Add support for packing sparse files
This commit adds support for packing sparse files into squashfs images as follows: - In the data writer: simply detect zero blocks and write a zero to the block size field and don't emit any data. Record the number of bytes saved this way. For fragments, set the fragment offset to invalid. - In the inode writer: write out the number of bytes saved for sparse files. If there should be a fragment but there is none, append a block count of 0. - In the data reader: if the block size is 0, read nothing from disk and emit an empty block. Do the same if the fragment is missing. - In the inode reader: restore the number of bytes saved for sparse files. The sparse files can be packed and unpacked, but the unpacking will not create sparse files for now. Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>
Diffstat (limited to 'lib/sqfs/write_inode.c')
-rw-r--r--lib/sqfs/write_inode.c12
1 files changed, 10 insertions, 2 deletions
diff --git a/lib/sqfs/write_inode.c b/lib/sqfs/write_inode.c
index fd14913..82663e7 100644
--- a/lib/sqfs/write_inode.c
+++ b/lib/sqfs/write_inode.c
@@ -86,7 +86,7 @@ int meta_writer_write_inode(fstree_t *fs, id_table_t *idtbl, meta_writer_t *im,
fi = node->data.file;
if (fi->startblock > 0xFFFFFFFFUL || fi->size > 0xFFFFFFFFUL ||
- hard_link_count(node) > 1) {
+ hard_link_count(node) > 1 || fi->sparse > 0) {
type = SQFS_INODE_EXT_FILE;
}
}
@@ -185,7 +185,7 @@ int meta_writer_write_inode(fstree_t *fs, id_table_t *idtbl, meta_writer_t *im,
sqfs_inode_file_ext_t ext = {
.blocks_start = htole64(fi->startblock),
.file_size = htole64(fi->size),
- .sparse = htole64(0),
+ .sparse = htole64(fi->sparse),
.nlink = htole32(hard_link_count(node)),
.fragment_idx = htole32(0xFFFFFFFF),
.fragment_offset = htole32(0xFFFFFFFF),
@@ -298,5 +298,13 @@ out_file_blocks:
if (meta_writer_append(im, &bs, sizeof(bs)))
return -1;
}
+
+ if ((fi->size % fs->block_size) != 0 &&
+ (fi->fragment == 0xFFFFFFFF || fi->fragment_offset == 0xFFFFFFFF)) {
+ bs = htole32(0);
+
+ if (meta_writer_append(im, &bs, sizeof(bs)))
+ return -1;
+ }
return 0;
}