fs/erofs/erofs_fs.h

1 /* SPDX-License-Identifier: GPL-2.0-only OR Apache-2.0 */
3  * EROFS (Enhanced ROM File System) on-disk format definition
5  * Copyright (C) 2017-2018 HUAWEI, Inc.
54 /* erofs on-disk super block (currently 128 bytes) */
63 	__le64 inos;            /* total valid ino # (== f_files - f_favail) */
70 	__u8 uuid[16];          /* 128-bit uuid for volume */
90  * EROFS inode datalayout (i_format in on-disk inode):
91  * 0 - uncompressed flat inode without tail-packing inline data:
92  * 1 - compressed inode with non-compact indexes:
93  * 2 - uncompressed flat inode with tail-packing inline data:
94  * 3 - compressed inode with compact indexes:
95  * 4 - chunk-based inode with (optional) multi-device support:
96  * 5~7 - reserved
121 #define EROFS_I_ALL	((1 << EROFS_I_ALL_BIT) - 1)
125 /* with chunk indexes or just a 4-byte blkaddr array */
131 /* 32-byte on-disk inode */
133 /* 64-byte on-disk inode */
151 	/* for chunk-based files, it contains the summary info */
155 /* 32-byte reduced form of an ondisk inode */
159 /* 1 header + n-1 * 4 bytes inline xattr to keep continuity */
167 	__le32 i_ino;		/* only used for 32-bit stat compatibility */
173 /* 64-byte complete form of an ondisk inode */
177 /* 1 header + n-1 * 4 bytes inline xattr to keep continuity */
184 	__le32 i_ino;		/* only used for 32-bit stat compatibility */
195  * erofs_xattr_ibody_header(1) + (n - 1) * 4 bytes
198  *                           /-----------------------\
200  *                           +-----------------------+
202  * for read-only fs, no need to introduce h_refcount
205 	__le32 h_name_filter;		/* bit value 1 indicates not-present */
251 		sizeof(__u32) * (le16_to_cpu(i_xattr_icount) - 1);  in erofs_xattr_ibody_size()
259 				 e->e_name_len + le16_to_cpu(e->e_value_size));  in erofs_xattr_entry_size()
263 #define EROFS_NULL_ADDR			-1
265 /* 4-byte block address array */
268 /* 8-byte inode chunk indexes */
271 	__le16 device_id;	/* back-end storage id (with bits masked) */
291 /* maximum supported size of a physical compression cluster */
301 #define Z_EROFS_ALL_COMPR_ALGS		((1 << Z_EROFS_COMPRESSION_MAX) - 1)
326  * bit 0 : COMPACTED_2B indexes (0 - off; 1 - on)
327  *  e.g. for 4k logical cluster size,      4B        if compacted 2B is off;
329  * bit 1 : HEAD1 big pcluster (0 - off; 1 - on)
330  * bit 2 : HEAD2 big pcluster (0 - off; 1 - on)
331  * bit 3 : tailpacking inline pcluster (0 - off; 1 - on)
332  * bit 4 : interlaced plain pcluster (0 - off; 1 - on)
333  * bit 5 : fragment pcluster (0 - off; 1 - on)
355 	 * bit 0-3 : algorithm type of head 1 (logical cluster type 01);
356 	 * bit 4-7 : algorithm type of head 2 (logical cluster type 11).
360 	 * bit 0-2 : logical cluster bits - 12, e.g. 0 for 4096;
361 	 * bit 3-6 : reserved;
368  * On-disk logical cluster type:
369  *    0   - literal (uncompressed) lcluster
370  *    1,3 - compressed lcluster (for HEAD lclusters)
371  *    2   - compressed lcluster (for NONHEAD lclusters)
374  *    0 - literal (uncompressed) lcluster,
379  *    1,3 - compressed lcluster (for HEAD lclusters)
384  *    2 - compressed lcluster (for NONHEAD lclusters)
406  * D0_CBLKCNT will be marked _only_ at the 1st non-head lcluster to store the
422 		 * [0] - distance to its HEAD lcluster
423 		 * [1] - distance to the next HEAD lcluster
432 /* check the EROFS on-disk layout strictly at compile time */
455 		     Z_EROFS_LCLUSTER_TYPE_MAX - 1);  in erofs_check_ondisk_layout_definitions()