1 // SPDX-License-Identifier: GPL-2.0-or-later
3  * Squashfs - a compressed read only filesystem for Linux
14  * The export code uses an inode lookup table to map inode numbers passed in
15  * filehandles to an inode location on disk.  This table is stored compressed
16  * into metadata blocks.  A second index table is used to locate these.  This
17  * second index table for speed of access (and because it is small) is read at
20  * The inode lookup table is used only by the export code, inode disk
22  * without an intermediate lookup for all operations except the export ops.
37  * Look-up inode number (ino) in table, returning the inode location.
41 	struct squashfs_sb_info *msblk = sb->s_fs_info;  in squashfs_inode_lookup()
42 	int blk = SQUASHFS_LOOKUP_BLOCK(ino_num - 1);  in squashfs_inode_lookup()
43 	int offset = SQUASHFS_LOOKUP_BLOCK_OFFSET(ino_num - 1);  in squashfs_inode_lookup()
50 	if (ino_num == 0 || (ino_num - 1) >= msblk->inodes)  in squashfs_inode_lookup()
51 		return -EINVAL;  in squashfs_inode_lookup()
53 	start = le64_to_cpu(msblk->inode_lookup_table[blk]);  in squashfs_inode_lookup()
70 	struct dentry *dentry = ERR_PTR(-ENOENT);  in squashfs_export_iget()
89 	return squashfs_export_iget(sb, fid->i32.ino);  in squashfs_fh_to_dentry()
99 	return squashfs_export_iget(sb, fid->i32.parent_ino);  in squashfs_fh_to_parent()
106 	unsigned int parent_ino = squashfs_i(inode)->parent;  in squashfs_get_parent()
108 	return squashfs_export_iget(inode->i_sb, parent_ino);  in squashfs_get_parent()
113  * Read uncompressed inode lookup table indexes off disk into memory
121 	__le64 *table;  in squashfs_read_inode_lookup_table()  local
130 		return ERR_PTR(-EINVAL);  in squashfs_read_inode_lookup_table()
133 	 * The computed size of the lookup table (length bytes) should exactly  in squashfs_read_inode_lookup_table()
134 	 * match the table start and end points  in squashfs_read_inode_lookup_table()
136 	if (length != (next_table - lookup_table_start))  in squashfs_read_inode_lookup_table()
137 		return ERR_PTR(-EINVAL);  in squashfs_read_inode_lookup_table()
139 	table = squashfs_read_table(sb, lookup_table_start, length);  in squashfs_read_inode_lookup_table()
140 	if (IS_ERR(table))  in squashfs_read_inode_lookup_table()
141 		return table;  in squashfs_read_inode_lookup_table()
144 	 * table0], table[1], ... table[indexes - 1] store the locations  in squashfs_read_inode_lookup_table()
145 	 * of the compressed inode lookup blocks.  Each entry should be  in squashfs_read_inode_lookup_table()
146 	 * less than the next (i.e. table[0] < table[1]), and the difference  in squashfs_read_inode_lookup_table()
148 	 * table[indexes - 1] should  be less than lookup_table_start, and  in squashfs_read_inode_lookup_table()
151 	for (n = 0; n < (indexes - 1); n++) {  in squashfs_read_inode_lookup_table()
152 		start = le64_to_cpu(table[n]);  in squashfs_read_inode_lookup_table()
153 		end = le64_to_cpu(table[n + 1]);  in squashfs_read_inode_lookup_table()
156 		    || (end - start) >  in squashfs_read_inode_lookup_table()
158 			kfree(table);  in squashfs_read_inode_lookup_table()
159 			return ERR_PTR(-EINVAL);  in squashfs_read_inode_lookup_table()
163 	start = le64_to_cpu(table[indexes - 1]);  in squashfs_read_inode_lookup_table()
165 	    (lookup_table_start - start) >  in squashfs_read_inode_lookup_table()
167 		kfree(table);  in squashfs_read_inode_lookup_table()
168 		return ERR_PTR(-EINVAL);  in squashfs_read_inode_lookup_table()
171 	return table;  in squashfs_read_inode_lookup_table()