fs/squashfs/fragment.c

1 // SPDX-License-Identifier: GPL-2.0-or-later
3  * Squashfs - a compressed read only filesystem for Linux
12  * This file implements code to handle compressed fragments (tail-end packed
16  * location on disk and compressed size using a fragment lookup table.
17  * Like everything in Squashfs this fragment lookup table is itself stored
18  * compressed into metadata blocks.  A second index table is used to locate
19  * these.  This second index table for speed of access (and because it
32  * Look-up fragment using the fragment index table.  Return the on disk
38 	struct squashfs_sb_info *msblk = sb->s_fs_info;  in squashfs_frag_lookup()
43 	if (fragment >= msblk->fragments)  in squashfs_frag_lookup()
44 		return -EIO;  in squashfs_frag_lookup()
48 	start_block = le64_to_cpu(msblk->fragment_index[block]);  in squashfs_frag_lookup()
61  * Read the uncompressed fragment lookup table indexes off disk into memory
67 	__le64 *table;  in squashfs_read_fragment_index_table()  local
70 	 * Sanity check, length bytes should not extend into the next table -  in squashfs_read_fragment_index_table()
72 	 * incorrectly larger than the next table start  in squashfs_read_fragment_index_table()
75 		return ERR_PTR(-EINVAL);  in squashfs_read_fragment_index_table()
77 	table = squashfs_read_table(sb, fragment_table_start, length);  in squashfs_read_fragment_index_table()
80 	 * table[0] points to the first fragment table metadata block, this  in squashfs_read_fragment_index_table()
83 	if (!IS_ERR(table) && le64_to_cpu(table[0]) >= fragment_table_start) {  in squashfs_read_fragment_index_table()
84 		kfree(table);  in squashfs_read_fragment_index_table()
85 		return ERR_PTR(-EINVAL);  in squashfs_read_fragment_index_table()
88 	return table;  in squashfs_read_fragment_index_table()