xref: /openbmc/linux/fs/ext2/ext2.h (revision e3b9f1e8)
1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*
3  * Copyright (C) 1992, 1993, 1994, 1995
4  * Remy Card (card@masi.ibp.fr)
5  * Laboratoire MASI - Institut Blaise Pascal
6  * Universite Pierre et Marie Curie (Paris VI)
7  *
8  *  from
9  *
10  *  linux/include/linux/minix_fs.h
11  *
12  *  Copyright (C) 1991, 1992  Linus Torvalds
13  */
14 #include <linux/fs.h>
15 #include <linux/ext2_fs.h>
16 #include <linux/blockgroup_lock.h>
17 #include <linux/percpu_counter.h>
18 #include <linux/rbtree.h>
19 
20 /* XXX Here for now... not interested in restructing headers JUST now */
21 
22 /* data type for block offset of block group */
23 typedef int ext2_grpblk_t;
24 
25 /* data type for filesystem-wide blocks number */
26 typedef unsigned long ext2_fsblk_t;
27 
28 #define E2FSBLK "%lu"
29 
30 struct ext2_reserve_window {
31 	ext2_fsblk_t		_rsv_start;	/* First byte reserved */
32 	ext2_fsblk_t		_rsv_end;	/* Last byte reserved or 0 */
33 };
34 
35 struct ext2_reserve_window_node {
36 	struct rb_node	 	rsv_node;
37 	__u32			rsv_goal_size;
38 	__u32			rsv_alloc_hit;
39 	struct ext2_reserve_window	rsv_window;
40 };
41 
42 struct ext2_block_alloc_info {
43 	/* information about reservation window */
44 	struct ext2_reserve_window_node	rsv_window_node;
45 	/*
46 	 * was i_next_alloc_block in ext2_inode_info
47 	 * is the logical (file-relative) number of the
48 	 * most-recently-allocated block in this file.
49 	 * We use this for detecting linearly ascending allocation requests.
50 	 */
51 	__u32			last_alloc_logical_block;
52 	/*
53 	 * Was i_next_alloc_goal in ext2_inode_info
54 	 * is the *physical* companion to i_next_alloc_block.
55 	 * it the the physical block number of the block which was most-recentl
56 	 * allocated to this file.  This give us the goal (target) for the next
57 	 * allocation when we detect linearly ascending requests.
58 	 */
59 	ext2_fsblk_t		last_alloc_physical_block;
60 };
61 
62 #define rsv_start rsv_window._rsv_start
63 #define rsv_end rsv_window._rsv_end
64 
65 struct mb_cache;
66 
67 /*
68  * second extended-fs super-block data in memory
69  */
70 struct ext2_sb_info {
71 	unsigned long s_frag_size;	/* Size of a fragment in bytes */
72 	unsigned long s_frags_per_block;/* Number of fragments per block */
73 	unsigned long s_inodes_per_block;/* Number of inodes per block */
74 	unsigned long s_frags_per_group;/* Number of fragments in a group */
75 	unsigned long s_blocks_per_group;/* Number of blocks in a group */
76 	unsigned long s_inodes_per_group;/* Number of inodes in a group */
77 	unsigned long s_itb_per_group;	/* Number of inode table blocks per group */
78 	unsigned long s_gdb_count;	/* Number of group descriptor blocks */
79 	unsigned long s_desc_per_block;	/* Number of group descriptors per block */
80 	unsigned long s_groups_count;	/* Number of groups in the fs */
81 	unsigned long s_overhead_last;  /* Last calculated overhead */
82 	unsigned long s_blocks_last;    /* Last seen block count */
83 	struct buffer_head * s_sbh;	/* Buffer containing the super block */
84 	struct ext2_super_block * s_es;	/* Pointer to the super block in the buffer */
85 	struct buffer_head ** s_group_desc;
86 	unsigned long  s_mount_opt;
87 	unsigned long s_sb_block;
88 	kuid_t s_resuid;
89 	kgid_t s_resgid;
90 	unsigned short s_mount_state;
91 	unsigned short s_pad;
92 	int s_addr_per_block_bits;
93 	int s_desc_per_block_bits;
94 	int s_inode_size;
95 	int s_first_ino;
96 	spinlock_t s_next_gen_lock;
97 	u32 s_next_generation;
98 	unsigned long s_dir_count;
99 	u8 *s_debts;
100 	struct percpu_counter s_freeblocks_counter;
101 	struct percpu_counter s_freeinodes_counter;
102 	struct percpu_counter s_dirs_counter;
103 	struct blockgroup_lock *s_blockgroup_lock;
104 	/* root of the per fs reservation window tree */
105 	spinlock_t s_rsv_window_lock;
106 	struct rb_root s_rsv_window_root;
107 	struct ext2_reserve_window_node s_rsv_window_head;
108 	/*
109 	 * s_lock protects against concurrent modifications of s_mount_state,
110 	 * s_blocks_last, s_overhead_last and the content of superblock's
111 	 * buffer pointed to by sbi->s_es.
112 	 *
113 	 * Note: It is used in ext2_show_options() to provide a consistent view
114 	 * of the mount options.
115 	 */
116 	spinlock_t s_lock;
117 	struct mb_cache *s_ea_block_cache;
118 	struct dax_device *s_daxdev;
119 };
120 
121 static inline spinlock_t *
122 sb_bgl_lock(struct ext2_sb_info *sbi, unsigned int block_group)
123 {
124 	return bgl_lock_ptr(sbi->s_blockgroup_lock, block_group);
125 }
126 
127 /*
128  * Define EXT2FS_DEBUG to produce debug messages
129  */
130 #undef EXT2FS_DEBUG
131 
132 /*
133  * Define EXT2_RESERVATION to reserve data blocks for expanding files
134  */
135 #define EXT2_DEFAULT_RESERVE_BLOCKS     8
136 /*max window size: 1024(direct blocks) + 3([t,d]indirect blocks) */
137 #define EXT2_MAX_RESERVE_BLOCKS         1027
138 #define EXT2_RESERVE_WINDOW_NOT_ALLOCATED 0
139 /*
140  * The second extended file system version
141  */
142 #define EXT2FS_DATE		"95/08/09"
143 #define EXT2FS_VERSION		"0.5b"
144 
145 /*
146  * Debug code
147  */
148 #ifdef EXT2FS_DEBUG
149 #	define ext2_debug(f, a...)	{ \
150 					printk ("EXT2-fs DEBUG (%s, %d): %s:", \
151 						__FILE__, __LINE__, __func__); \
152 				  	printk (f, ## a); \
153 					}
154 #else
155 #	define ext2_debug(f, a...)	/**/
156 #endif
157 
158 /*
159  * Special inode numbers
160  */
161 #define	EXT2_BAD_INO		 1	/* Bad blocks inode */
162 #define EXT2_ROOT_INO		 2	/* Root inode */
163 #define EXT2_BOOT_LOADER_INO	 5	/* Boot loader inode */
164 #define EXT2_UNDEL_DIR_INO	 6	/* Undelete directory inode */
165 
166 /* First non-reserved inode for old ext2 filesystems */
167 #define EXT2_GOOD_OLD_FIRST_INO	11
168 
169 static inline struct ext2_sb_info *EXT2_SB(struct super_block *sb)
170 {
171 	return sb->s_fs_info;
172 }
173 
174 /*
175  * Macro-instructions used to manage several block sizes
176  */
177 #define EXT2_MIN_BLOCK_SIZE		1024
178 #define	EXT2_MAX_BLOCK_SIZE		4096
179 #define EXT2_MIN_BLOCK_LOG_SIZE		  10
180 #define EXT2_BLOCK_SIZE(s)		((s)->s_blocksize)
181 #define	EXT2_ADDR_PER_BLOCK(s)		(EXT2_BLOCK_SIZE(s) / sizeof (__u32))
182 #define EXT2_BLOCK_SIZE_BITS(s)		((s)->s_blocksize_bits)
183 #define	EXT2_ADDR_PER_BLOCK_BITS(s)	(EXT2_SB(s)->s_addr_per_block_bits)
184 #define EXT2_INODE_SIZE(s)		(EXT2_SB(s)->s_inode_size)
185 #define EXT2_FIRST_INO(s)		(EXT2_SB(s)->s_first_ino)
186 
187 /*
188  * Macro-instructions used to manage fragments
189  */
190 #define EXT2_MIN_FRAG_SIZE		1024
191 #define	EXT2_MAX_FRAG_SIZE		4096
192 #define EXT2_MIN_FRAG_LOG_SIZE		  10
193 #define EXT2_FRAG_SIZE(s)		(EXT2_SB(s)->s_frag_size)
194 #define EXT2_FRAGS_PER_BLOCK(s)		(EXT2_SB(s)->s_frags_per_block)
195 
196 /*
197  * Structure of a blocks group descriptor
198  */
199 struct ext2_group_desc
200 {
201 	__le32	bg_block_bitmap;		/* Blocks bitmap block */
202 	__le32	bg_inode_bitmap;		/* Inodes bitmap block */
203 	__le32	bg_inode_table;		/* Inodes table block */
204 	__le16	bg_free_blocks_count;	/* Free blocks count */
205 	__le16	bg_free_inodes_count;	/* Free inodes count */
206 	__le16	bg_used_dirs_count;	/* Directories count */
207 	__le16	bg_pad;
208 	__le32	bg_reserved[3];
209 };
210 
211 /*
212  * Macro-instructions used to manage group descriptors
213  */
214 #define EXT2_BLOCKS_PER_GROUP(s)	(EXT2_SB(s)->s_blocks_per_group)
215 #define EXT2_DESC_PER_BLOCK(s)		(EXT2_SB(s)->s_desc_per_block)
216 #define EXT2_INODES_PER_GROUP(s)	(EXT2_SB(s)->s_inodes_per_group)
217 #define EXT2_DESC_PER_BLOCK_BITS(s)	(EXT2_SB(s)->s_desc_per_block_bits)
218 
219 /*
220  * Constants relative to the data blocks
221  */
222 #define	EXT2_NDIR_BLOCKS		12
223 #define	EXT2_IND_BLOCK			EXT2_NDIR_BLOCKS
224 #define	EXT2_DIND_BLOCK			(EXT2_IND_BLOCK + 1)
225 #define	EXT2_TIND_BLOCK			(EXT2_DIND_BLOCK + 1)
226 #define	EXT2_N_BLOCKS			(EXT2_TIND_BLOCK + 1)
227 
228 /*
229  * Inode flags (GETFLAGS/SETFLAGS)
230  */
231 #define	EXT2_SECRM_FL			FS_SECRM_FL	/* Secure deletion */
232 #define	EXT2_UNRM_FL			FS_UNRM_FL	/* Undelete */
233 #define	EXT2_COMPR_FL			FS_COMPR_FL	/* Compress file */
234 #define EXT2_SYNC_FL			FS_SYNC_FL	/* Synchronous updates */
235 #define EXT2_IMMUTABLE_FL		FS_IMMUTABLE_FL	/* Immutable file */
236 #define EXT2_APPEND_FL			FS_APPEND_FL	/* writes to file may only append */
237 #define EXT2_NODUMP_FL			FS_NODUMP_FL	/* do not dump file */
238 #define EXT2_NOATIME_FL			FS_NOATIME_FL	/* do not update atime */
239 /* Reserved for compression usage... */
240 #define EXT2_DIRTY_FL			FS_DIRTY_FL
241 #define EXT2_COMPRBLK_FL		FS_COMPRBLK_FL	/* One or more compressed clusters */
242 #define EXT2_NOCOMP_FL			FS_NOCOMP_FL	/* Don't compress */
243 #define EXT2_ECOMPR_FL			FS_ECOMPR_FL	/* Compression error */
244 /* End compression flags --- maybe not all used */
245 #define EXT2_BTREE_FL			FS_BTREE_FL	/* btree format dir */
246 #define EXT2_INDEX_FL			FS_INDEX_FL	/* hash-indexed directory */
247 #define EXT2_IMAGIC_FL			FS_IMAGIC_FL	/* AFS directory */
248 #define EXT2_JOURNAL_DATA_FL		FS_JOURNAL_DATA_FL /* Reserved for ext3 */
249 #define EXT2_NOTAIL_FL			FS_NOTAIL_FL	/* file tail should not be merged */
250 #define EXT2_DIRSYNC_FL			FS_DIRSYNC_FL	/* dirsync behaviour (directories only) */
251 #define EXT2_TOPDIR_FL			FS_TOPDIR_FL	/* Top of directory hierarchies*/
252 #define EXT2_RESERVED_FL		FS_RESERVED_FL	/* reserved for ext2 lib */
253 
254 #define EXT2_FL_USER_VISIBLE		FS_FL_USER_VISIBLE	/* User visible flags */
255 #define EXT2_FL_USER_MODIFIABLE		FS_FL_USER_MODIFIABLE	/* User modifiable flags */
256 
257 /* Flags that should be inherited by new inodes from their parent. */
258 #define EXT2_FL_INHERITED (EXT2_SECRM_FL | EXT2_UNRM_FL | EXT2_COMPR_FL |\
259 			   EXT2_SYNC_FL | EXT2_NODUMP_FL |\
260 			   EXT2_NOATIME_FL | EXT2_COMPRBLK_FL |\
261 			   EXT2_NOCOMP_FL | EXT2_JOURNAL_DATA_FL |\
262 			   EXT2_NOTAIL_FL | EXT2_DIRSYNC_FL)
263 
264 /* Flags that are appropriate for regular files (all but dir-specific ones). */
265 #define EXT2_REG_FLMASK (~(EXT2_DIRSYNC_FL | EXT2_TOPDIR_FL))
266 
267 /* Flags that are appropriate for non-directories/regular files. */
268 #define EXT2_OTHER_FLMASK (EXT2_NODUMP_FL | EXT2_NOATIME_FL)
269 
270 /* Mask out flags that are inappropriate for the given type of inode. */
271 static inline __u32 ext2_mask_flags(umode_t mode, __u32 flags)
272 {
273 	if (S_ISDIR(mode))
274 		return flags;
275 	else if (S_ISREG(mode))
276 		return flags & EXT2_REG_FLMASK;
277 	else
278 		return flags & EXT2_OTHER_FLMASK;
279 }
280 
281 /*
282  * ioctl commands
283  */
284 #define	EXT2_IOC_GETFLAGS		FS_IOC_GETFLAGS
285 #define	EXT2_IOC_SETFLAGS		FS_IOC_SETFLAGS
286 #define	EXT2_IOC_GETVERSION		FS_IOC_GETVERSION
287 #define	EXT2_IOC_SETVERSION		FS_IOC_SETVERSION
288 #define	EXT2_IOC_GETRSVSZ		_IOR('f', 5, long)
289 #define	EXT2_IOC_SETRSVSZ		_IOW('f', 6, long)
290 
291 /*
292  * ioctl commands in 32 bit emulation
293  */
294 #define EXT2_IOC32_GETFLAGS		FS_IOC32_GETFLAGS
295 #define EXT2_IOC32_SETFLAGS		FS_IOC32_SETFLAGS
296 #define EXT2_IOC32_GETVERSION		FS_IOC32_GETVERSION
297 #define EXT2_IOC32_SETVERSION		FS_IOC32_SETVERSION
298 
299 /*
300  * Structure of an inode on the disk
301  */
302 struct ext2_inode {
303 	__le16	i_mode;		/* File mode */
304 	__le16	i_uid;		/* Low 16 bits of Owner Uid */
305 	__le32	i_size;		/* Size in bytes */
306 	__le32	i_atime;	/* Access time */
307 	__le32	i_ctime;	/* Creation time */
308 	__le32	i_mtime;	/* Modification time */
309 	__le32	i_dtime;	/* Deletion Time */
310 	__le16	i_gid;		/* Low 16 bits of Group Id */
311 	__le16	i_links_count;	/* Links count */
312 	__le32	i_blocks;	/* Blocks count */
313 	__le32	i_flags;	/* File flags */
314 	union {
315 		struct {
316 			__le32  l_i_reserved1;
317 		} linux1;
318 		struct {
319 			__le32  h_i_translator;
320 		} hurd1;
321 		struct {
322 			__le32  m_i_reserved1;
323 		} masix1;
324 	} osd1;				/* OS dependent 1 */
325 	__le32	i_block[EXT2_N_BLOCKS];/* Pointers to blocks */
326 	__le32	i_generation;	/* File version (for NFS) */
327 	__le32	i_file_acl;	/* File ACL */
328 	__le32	i_dir_acl;	/* Directory ACL */
329 	__le32	i_faddr;	/* Fragment address */
330 	union {
331 		struct {
332 			__u8	l_i_frag;	/* Fragment number */
333 			__u8	l_i_fsize;	/* Fragment size */
334 			__u16	i_pad1;
335 			__le16	l_i_uid_high;	/* these 2 fields    */
336 			__le16	l_i_gid_high;	/* were reserved2[0] */
337 			__u32	l_i_reserved2;
338 		} linux2;
339 		struct {
340 			__u8	h_i_frag;	/* Fragment number */
341 			__u8	h_i_fsize;	/* Fragment size */
342 			__le16	h_i_mode_high;
343 			__le16	h_i_uid_high;
344 			__le16	h_i_gid_high;
345 			__le32	h_i_author;
346 		} hurd2;
347 		struct {
348 			__u8	m_i_frag;	/* Fragment number */
349 			__u8	m_i_fsize;	/* Fragment size */
350 			__u16	m_pad1;
351 			__u32	m_i_reserved2[2];
352 		} masix2;
353 	} osd2;				/* OS dependent 2 */
354 };
355 
356 #define i_size_high	i_dir_acl
357 
358 #define i_reserved1	osd1.linux1.l_i_reserved1
359 #define i_frag		osd2.linux2.l_i_frag
360 #define i_fsize		osd2.linux2.l_i_fsize
361 #define i_uid_low	i_uid
362 #define i_gid_low	i_gid
363 #define i_uid_high	osd2.linux2.l_i_uid_high
364 #define i_gid_high	osd2.linux2.l_i_gid_high
365 #define i_reserved2	osd2.linux2.l_i_reserved2
366 
367 /*
368  * File system states
369  */
370 #define	EXT2_VALID_FS			0x0001	/* Unmounted cleanly */
371 #define	EXT2_ERROR_FS			0x0002	/* Errors detected */
372 #define	EFSCORRUPTED			EUCLEAN	/* Filesystem is corrupted */
373 
374 /*
375  * Mount flags
376  */
377 #define EXT2_MOUNT_CHECK		0x000001  /* Do mount-time checks */
378 #define EXT2_MOUNT_OLDALLOC		0x000002  /* Don't use the new Orlov allocator */
379 #define EXT2_MOUNT_GRPID		0x000004  /* Create files with directory's group */
380 #define EXT2_MOUNT_DEBUG		0x000008  /* Some debugging messages */
381 #define EXT2_MOUNT_ERRORS_CONT		0x000010  /* Continue on errors */
382 #define EXT2_MOUNT_ERRORS_RO		0x000020  /* Remount fs ro on errors */
383 #define EXT2_MOUNT_ERRORS_PANIC		0x000040  /* Panic on errors */
384 #define EXT2_MOUNT_MINIX_DF		0x000080  /* Mimics the Minix statfs */
385 #define EXT2_MOUNT_NOBH			0x000100  /* No buffer_heads */
386 #define EXT2_MOUNT_NO_UID32		0x000200  /* Disable 32-bit UIDs */
387 #define EXT2_MOUNT_XATTR_USER		0x004000  /* Extended user attributes */
388 #define EXT2_MOUNT_POSIX_ACL		0x008000  /* POSIX Access Control Lists */
389 #define EXT2_MOUNT_XIP			0x010000  /* Obsolete, use DAX */
390 #define EXT2_MOUNT_USRQUOTA		0x020000  /* user quota */
391 #define EXT2_MOUNT_GRPQUOTA		0x040000  /* group quota */
392 #define EXT2_MOUNT_RESERVATION		0x080000  /* Preallocation */
393 #ifdef CONFIG_FS_DAX
394 #define EXT2_MOUNT_DAX			0x100000  /* Direct Access */
395 #else
396 #define EXT2_MOUNT_DAX			0
397 #endif
398 
399 
400 #define clear_opt(o, opt)		o &= ~EXT2_MOUNT_##opt
401 #define set_opt(o, opt)			o |= EXT2_MOUNT_##opt
402 #define test_opt(sb, opt)		(EXT2_SB(sb)->s_mount_opt & \
403 					 EXT2_MOUNT_##opt)
404 /*
405  * Maximal mount counts between two filesystem checks
406  */
407 #define EXT2_DFL_MAX_MNT_COUNT		20	/* Allow 20 mounts */
408 #define EXT2_DFL_CHECKINTERVAL		0	/* Don't use interval check */
409 
410 /*
411  * Behaviour when detecting errors
412  */
413 #define EXT2_ERRORS_CONTINUE		1	/* Continue execution */
414 #define EXT2_ERRORS_RO			2	/* Remount fs read-only */
415 #define EXT2_ERRORS_PANIC		3	/* Panic */
416 #define EXT2_ERRORS_DEFAULT		EXT2_ERRORS_CONTINUE
417 
418 /*
419  * Structure of the super block
420  */
421 struct ext2_super_block {
422 	__le32	s_inodes_count;		/* Inodes count */
423 	__le32	s_blocks_count;		/* Blocks count */
424 	__le32	s_r_blocks_count;	/* Reserved blocks count */
425 	__le32	s_free_blocks_count;	/* Free blocks count */
426 	__le32	s_free_inodes_count;	/* Free inodes count */
427 	__le32	s_first_data_block;	/* First Data Block */
428 	__le32	s_log_block_size;	/* Block size */
429 	__le32	s_log_frag_size;	/* Fragment size */
430 	__le32	s_blocks_per_group;	/* # Blocks per group */
431 	__le32	s_frags_per_group;	/* # Fragments per group */
432 	__le32	s_inodes_per_group;	/* # Inodes per group */
433 	__le32	s_mtime;		/* Mount time */
434 	__le32	s_wtime;		/* Write time */
435 	__le16	s_mnt_count;		/* Mount count */
436 	__le16	s_max_mnt_count;	/* Maximal mount count */
437 	__le16	s_magic;		/* Magic signature */
438 	__le16	s_state;		/* File system state */
439 	__le16	s_errors;		/* Behaviour when detecting errors */
440 	__le16	s_minor_rev_level; 	/* minor revision level */
441 	__le32	s_lastcheck;		/* time of last check */
442 	__le32	s_checkinterval;	/* max. time between checks */
443 	__le32	s_creator_os;		/* OS */
444 	__le32	s_rev_level;		/* Revision level */
445 	__le16	s_def_resuid;		/* Default uid for reserved blocks */
446 	__le16	s_def_resgid;		/* Default gid for reserved blocks */
447 	/*
448 	 * These fields are for EXT2_DYNAMIC_REV superblocks only.
449 	 *
450 	 * Note: the difference between the compatible feature set and
451 	 * the incompatible feature set is that if there is a bit set
452 	 * in the incompatible feature set that the kernel doesn't
453 	 * know about, it should refuse to mount the filesystem.
454 	 *
455 	 * e2fsck's requirements are more strict; if it doesn't know
456 	 * about a feature in either the compatible or incompatible
457 	 * feature set, it must abort and not try to meddle with
458 	 * things it doesn't understand...
459 	 */
460 	__le32	s_first_ino; 		/* First non-reserved inode */
461 	__le16   s_inode_size; 		/* size of inode structure */
462 	__le16	s_block_group_nr; 	/* block group # of this superblock */
463 	__le32	s_feature_compat; 	/* compatible feature set */
464 	__le32	s_feature_incompat; 	/* incompatible feature set */
465 	__le32	s_feature_ro_compat; 	/* readonly-compatible feature set */
466 	__u8	s_uuid[16];		/* 128-bit uuid for volume */
467 	char	s_volume_name[16]; 	/* volume name */
468 	char	s_last_mounted[64]; 	/* directory where last mounted */
469 	__le32	s_algorithm_usage_bitmap; /* For compression */
470 	/*
471 	 * Performance hints.  Directory preallocation should only
472 	 * happen if the EXT2_COMPAT_PREALLOC flag is on.
473 	 */
474 	__u8	s_prealloc_blocks;	/* Nr of blocks to try to preallocate*/
475 	__u8	s_prealloc_dir_blocks;	/* Nr to preallocate for dirs */
476 	__u16	s_padding1;
477 	/*
478 	 * Journaling support valid if EXT3_FEATURE_COMPAT_HAS_JOURNAL set.
479 	 */
480 	__u8	s_journal_uuid[16];	/* uuid of journal superblock */
481 	__u32	s_journal_inum;		/* inode number of journal file */
482 	__u32	s_journal_dev;		/* device number of journal file */
483 	__u32	s_last_orphan;		/* start of list of inodes to delete */
484 	__u32	s_hash_seed[4];		/* HTREE hash seed */
485 	__u8	s_def_hash_version;	/* Default hash version to use */
486 	__u8	s_reserved_char_pad;
487 	__u16	s_reserved_word_pad;
488 	__le32	s_default_mount_opts;
489  	__le32	s_first_meta_bg; 	/* First metablock block group */
490 	__u32	s_reserved[190];	/* Padding to the end of the block */
491 };
492 
493 /*
494  * Codes for operating systems
495  */
496 #define EXT2_OS_LINUX		0
497 #define EXT2_OS_HURD		1
498 #define EXT2_OS_MASIX		2
499 #define EXT2_OS_FREEBSD		3
500 #define EXT2_OS_LITES		4
501 
502 /*
503  * Revision levels
504  */
505 #define EXT2_GOOD_OLD_REV	0	/* The good old (original) format */
506 #define EXT2_DYNAMIC_REV	1 	/* V2 format w/ dynamic inode sizes */
507 
508 #define EXT2_CURRENT_REV	EXT2_GOOD_OLD_REV
509 #define EXT2_MAX_SUPP_REV	EXT2_DYNAMIC_REV
510 
511 #define EXT2_GOOD_OLD_INODE_SIZE 128
512 
513 /*
514  * Feature set definitions
515  */
516 
517 #define EXT2_HAS_COMPAT_FEATURE(sb,mask)			\
518 	( EXT2_SB(sb)->s_es->s_feature_compat & cpu_to_le32(mask) )
519 #define EXT2_HAS_RO_COMPAT_FEATURE(sb,mask)			\
520 	( EXT2_SB(sb)->s_es->s_feature_ro_compat & cpu_to_le32(mask) )
521 #define EXT2_HAS_INCOMPAT_FEATURE(sb,mask)			\
522 	( EXT2_SB(sb)->s_es->s_feature_incompat & cpu_to_le32(mask) )
523 #define EXT2_SET_COMPAT_FEATURE(sb,mask)			\
524 	EXT2_SB(sb)->s_es->s_feature_compat |= cpu_to_le32(mask)
525 #define EXT2_SET_RO_COMPAT_FEATURE(sb,mask)			\
526 	EXT2_SB(sb)->s_es->s_feature_ro_compat |= cpu_to_le32(mask)
527 #define EXT2_SET_INCOMPAT_FEATURE(sb,mask)			\
528 	EXT2_SB(sb)->s_es->s_feature_incompat |= cpu_to_le32(mask)
529 #define EXT2_CLEAR_COMPAT_FEATURE(sb,mask)			\
530 	EXT2_SB(sb)->s_es->s_feature_compat &= ~cpu_to_le32(mask)
531 #define EXT2_CLEAR_RO_COMPAT_FEATURE(sb,mask)			\
532 	EXT2_SB(sb)->s_es->s_feature_ro_compat &= ~cpu_to_le32(mask)
533 #define EXT2_CLEAR_INCOMPAT_FEATURE(sb,mask)			\
534 	EXT2_SB(sb)->s_es->s_feature_incompat &= ~cpu_to_le32(mask)
535 
536 #define EXT2_FEATURE_COMPAT_DIR_PREALLOC	0x0001
537 #define EXT2_FEATURE_COMPAT_IMAGIC_INODES	0x0002
538 #define EXT3_FEATURE_COMPAT_HAS_JOURNAL		0x0004
539 #define EXT2_FEATURE_COMPAT_EXT_ATTR		0x0008
540 #define EXT2_FEATURE_COMPAT_RESIZE_INO		0x0010
541 #define EXT2_FEATURE_COMPAT_DIR_INDEX		0x0020
542 #define EXT2_FEATURE_COMPAT_ANY			0xffffffff
543 
544 #define EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER	0x0001
545 #define EXT2_FEATURE_RO_COMPAT_LARGE_FILE	0x0002
546 #define EXT2_FEATURE_RO_COMPAT_BTREE_DIR	0x0004
547 #define EXT2_FEATURE_RO_COMPAT_ANY		0xffffffff
548 
549 #define EXT2_FEATURE_INCOMPAT_COMPRESSION	0x0001
550 #define EXT2_FEATURE_INCOMPAT_FILETYPE		0x0002
551 #define EXT3_FEATURE_INCOMPAT_RECOVER		0x0004
552 #define EXT3_FEATURE_INCOMPAT_JOURNAL_DEV	0x0008
553 #define EXT2_FEATURE_INCOMPAT_META_BG		0x0010
554 #define EXT2_FEATURE_INCOMPAT_ANY		0xffffffff
555 
556 #define EXT2_FEATURE_COMPAT_SUPP	EXT2_FEATURE_COMPAT_EXT_ATTR
557 #define EXT2_FEATURE_INCOMPAT_SUPP	(EXT2_FEATURE_INCOMPAT_FILETYPE| \
558 					 EXT2_FEATURE_INCOMPAT_META_BG)
559 #define EXT2_FEATURE_RO_COMPAT_SUPP	(EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER| \
560 					 EXT2_FEATURE_RO_COMPAT_LARGE_FILE| \
561 					 EXT2_FEATURE_RO_COMPAT_BTREE_DIR)
562 #define EXT2_FEATURE_RO_COMPAT_UNSUPPORTED	~EXT2_FEATURE_RO_COMPAT_SUPP
563 #define EXT2_FEATURE_INCOMPAT_UNSUPPORTED	~EXT2_FEATURE_INCOMPAT_SUPP
564 
565 /*
566  * Default values for user and/or group using reserved blocks
567  */
568 #define	EXT2_DEF_RESUID		0
569 #define	EXT2_DEF_RESGID		0
570 
571 /*
572  * Default mount options
573  */
574 #define EXT2_DEFM_DEBUG		0x0001
575 #define EXT2_DEFM_BSDGROUPS	0x0002
576 #define EXT2_DEFM_XATTR_USER	0x0004
577 #define EXT2_DEFM_ACL		0x0008
578 #define EXT2_DEFM_UID16		0x0010
579     /* Not used by ext2, but reserved for use by ext3 */
580 #define EXT3_DEFM_JMODE		0x0060
581 #define EXT3_DEFM_JMODE_DATA	0x0020
582 #define EXT3_DEFM_JMODE_ORDERED	0x0040
583 #define EXT3_DEFM_JMODE_WBACK	0x0060
584 
585 /*
586  * Structure of a directory entry
587  */
588 
589 struct ext2_dir_entry {
590 	__le32	inode;			/* Inode number */
591 	__le16	rec_len;		/* Directory entry length */
592 	__le16	name_len;		/* Name length */
593 	char	name[];			/* File name, up to EXT2_NAME_LEN */
594 };
595 
596 /*
597  * The new version of the directory entry.  Since EXT2 structures are
598  * stored in intel byte order, and the name_len field could never be
599  * bigger than 255 chars, it's safe to reclaim the extra byte for the
600  * file_type field.
601  */
602 struct ext2_dir_entry_2 {
603 	__le32	inode;			/* Inode number */
604 	__le16	rec_len;		/* Directory entry length */
605 	__u8	name_len;		/* Name length */
606 	__u8	file_type;
607 	char	name[];			/* File name, up to EXT2_NAME_LEN */
608 };
609 
610 /*
611  * Ext2 directory file types.  Only the low 3 bits are used.  The
612  * other bits are reserved for now.
613  */
614 enum {
615 	EXT2_FT_UNKNOWN		= 0,
616 	EXT2_FT_REG_FILE	= 1,
617 	EXT2_FT_DIR		= 2,
618 	EXT2_FT_CHRDEV		= 3,
619 	EXT2_FT_BLKDEV		= 4,
620 	EXT2_FT_FIFO		= 5,
621 	EXT2_FT_SOCK		= 6,
622 	EXT2_FT_SYMLINK		= 7,
623 	EXT2_FT_MAX
624 };
625 
626 /*
627  * EXT2_DIR_PAD defines the directory entries boundaries
628  *
629  * NOTE: It must be a multiple of 4
630  */
631 #define EXT2_DIR_PAD		 	4
632 #define EXT2_DIR_ROUND 			(EXT2_DIR_PAD - 1)
633 #define EXT2_DIR_REC_LEN(name_len)	(((name_len) + 8 + EXT2_DIR_ROUND) & \
634 					 ~EXT2_DIR_ROUND)
635 #define EXT2_MAX_REC_LEN		((1<<16)-1)
636 
637 static inline void verify_offsets(void)
638 {
639 #define A(x,y) BUILD_BUG_ON(x != offsetof(struct ext2_super_block, y));
640 	A(EXT2_SB_MAGIC_OFFSET, s_magic);
641 	A(EXT2_SB_BLOCKS_OFFSET, s_blocks_count);
642 	A(EXT2_SB_BSIZE_OFFSET, s_log_block_size);
643 #undef A
644 }
645 
646 /*
647  * ext2 mount options
648  */
649 struct ext2_mount_options {
650 	unsigned long s_mount_opt;
651 	kuid_t s_resuid;
652 	kgid_t s_resgid;
653 };
654 
655 /*
656  * second extended file system inode data in memory
657  */
658 struct ext2_inode_info {
659 	__le32	i_data[15];
660 	__u32	i_flags;
661 	__u32	i_faddr;
662 	__u8	i_frag_no;
663 	__u8	i_frag_size;
664 	__u16	i_state;
665 	__u32	i_file_acl;
666 	__u32	i_dir_acl;
667 	__u32	i_dtime;
668 
669 	/*
670 	 * i_block_group is the number of the block group which contains
671 	 * this file's inode.  Constant across the lifetime of the inode,
672 	 * it is used for making block allocation decisions - we try to
673 	 * place a file's data blocks near its inode block, and new inodes
674 	 * near to their parent directory's inode.
675 	 */
676 	__u32	i_block_group;
677 
678 	/* block reservation info */
679 	struct ext2_block_alloc_info *i_block_alloc_info;
680 
681 	__u32	i_dir_start_lookup;
682 #ifdef CONFIG_EXT2_FS_XATTR
683 	/*
684 	 * Extended attributes can be read independently of the main file
685 	 * data. Taking i_mutex even when reading would cause contention
686 	 * between readers of EAs and writers of regular file data, so
687 	 * instead we synchronize on xattr_sem when reading or changing
688 	 * EAs.
689 	 */
690 	struct rw_semaphore xattr_sem;
691 #endif
692 	rwlock_t i_meta_lock;
693 #ifdef CONFIG_FS_DAX
694 	struct rw_semaphore dax_sem;
695 #endif
696 
697 	/*
698 	 * truncate_mutex is for serialising ext2_truncate() against
699 	 * ext2_getblock().  It also protects the internals of the inode's
700 	 * reservation data structures: ext2_reserve_window and
701 	 * ext2_reserve_window_node.
702 	 */
703 	struct mutex truncate_mutex;
704 	struct inode	vfs_inode;
705 	struct list_head i_orphan;	/* unlinked but open inodes */
706 #ifdef CONFIG_QUOTA
707 	struct dquot *i_dquot[MAXQUOTAS];
708 #endif
709 };
710 
711 #ifdef CONFIG_FS_DAX
712 #define dax_sem_down_write(ext2_inode)	down_write(&(ext2_inode)->dax_sem)
713 #define dax_sem_up_write(ext2_inode)	up_write(&(ext2_inode)->dax_sem)
714 #else
715 #define dax_sem_down_write(ext2_inode)
716 #define dax_sem_up_write(ext2_inode)
717 #endif
718 
719 /*
720  * Inode dynamic state flags
721  */
722 #define EXT2_STATE_NEW			0x00000001 /* inode is newly created */
723 
724 
725 /*
726  * Function prototypes
727  */
728 
729 /*
730  * Ok, these declarations are also in <linux/kernel.h> but none of the
731  * ext2 source programs needs to include it so they are duplicated here.
732  */
733 
734 static inline struct ext2_inode_info *EXT2_I(struct inode *inode)
735 {
736 	return container_of(inode, struct ext2_inode_info, vfs_inode);
737 }
738 
739 /* balloc.c */
740 extern int ext2_bg_has_super(struct super_block *sb, int group);
741 extern unsigned long ext2_bg_num_gdb(struct super_block *sb, int group);
742 extern ext2_fsblk_t ext2_new_block(struct inode *, unsigned long, int *);
743 extern ext2_fsblk_t ext2_new_blocks(struct inode *, unsigned long,
744 				unsigned long *, int *);
745 extern int ext2_data_block_valid(struct ext2_sb_info *sbi, ext2_fsblk_t start_blk,
746 				 unsigned int count);
747 extern void ext2_free_blocks (struct inode *, unsigned long,
748 			      unsigned long);
749 extern unsigned long ext2_count_free_blocks (struct super_block *);
750 extern unsigned long ext2_count_dirs (struct super_block *);
751 extern void ext2_check_blocks_bitmap (struct super_block *);
752 extern struct ext2_group_desc * ext2_get_group_desc(struct super_block * sb,
753 						    unsigned int block_group,
754 						    struct buffer_head ** bh);
755 extern void ext2_discard_reservation (struct inode *);
756 extern int ext2_should_retry_alloc(struct super_block *sb, int *retries);
757 extern void ext2_init_block_alloc_info(struct inode *);
758 extern void ext2_rsv_window_add(struct super_block *sb, struct ext2_reserve_window_node *rsv);
759 
760 /* dir.c */
761 extern int ext2_add_link (struct dentry *, struct inode *);
762 extern ino_t ext2_inode_by_name(struct inode *, const struct qstr *);
763 extern int ext2_make_empty(struct inode *, struct inode *);
764 extern struct ext2_dir_entry_2 * ext2_find_entry (struct inode *,const struct qstr *, struct page **);
765 extern int ext2_delete_entry (struct ext2_dir_entry_2 *, struct page *);
766 extern int ext2_empty_dir (struct inode *);
767 extern struct ext2_dir_entry_2 * ext2_dotdot (struct inode *, struct page **);
768 extern void ext2_set_link(struct inode *, struct ext2_dir_entry_2 *, struct page *, struct inode *, int);
769 
770 /* ialloc.c */
771 extern struct inode * ext2_new_inode (struct inode *, umode_t, const struct qstr *);
772 extern void ext2_free_inode (struct inode *);
773 extern unsigned long ext2_count_free_inodes (struct super_block *);
774 extern void ext2_check_inodes_bitmap (struct super_block *);
775 extern unsigned long ext2_count_free (struct buffer_head *, unsigned);
776 
777 /* inode.c */
778 extern struct inode *ext2_iget (struct super_block *, unsigned long);
779 extern int ext2_write_inode (struct inode *, struct writeback_control *);
780 extern void ext2_evict_inode(struct inode *);
781 extern int ext2_get_block(struct inode *, sector_t, struct buffer_head *, int);
782 extern int ext2_setattr (struct dentry *, struct iattr *);
783 extern void ext2_set_inode_flags(struct inode *inode);
784 extern int ext2_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
785 		       u64 start, u64 len);
786 
787 /* ioctl.c */
788 extern long ext2_ioctl(struct file *, unsigned int, unsigned long);
789 extern long ext2_compat_ioctl(struct file *, unsigned int, unsigned long);
790 
791 /* namei.c */
792 struct dentry *ext2_get_parent(struct dentry *child);
793 
794 /* super.c */
795 extern __printf(3, 4)
796 void ext2_error(struct super_block *, const char *, const char *, ...);
797 extern __printf(3, 4)
798 void ext2_msg(struct super_block *, const char *, const char *, ...);
799 extern void ext2_update_dynamic_rev (struct super_block *sb);
800 extern void ext2_sync_super(struct super_block *sb, struct ext2_super_block *es,
801 			    int wait);
802 
803 /*
804  * Inodes and files operations
805  */
806 
807 /* dir.c */
808 extern const struct file_operations ext2_dir_operations;
809 
810 /* file.c */
811 extern int ext2_fsync(struct file *file, loff_t start, loff_t end,
812 		      int datasync);
813 extern const struct inode_operations ext2_file_inode_operations;
814 extern const struct file_operations ext2_file_operations;
815 
816 /* inode.c */
817 extern const struct address_space_operations ext2_aops;
818 extern const struct address_space_operations ext2_nobh_aops;
819 extern const struct iomap_ops ext2_iomap_ops;
820 
821 /* namei.c */
822 extern const struct inode_operations ext2_dir_inode_operations;
823 extern const struct inode_operations ext2_special_inode_operations;
824 
825 /* symlink.c */
826 extern const struct inode_operations ext2_fast_symlink_inode_operations;
827 extern const struct inode_operations ext2_symlink_inode_operations;
828 
829 static inline ext2_fsblk_t
830 ext2_group_first_block_no(struct super_block *sb, unsigned long group_no)
831 {
832 	return group_no * (ext2_fsblk_t)EXT2_BLOCKS_PER_GROUP(sb) +
833 		le32_to_cpu(EXT2_SB(sb)->s_es->s_first_data_block);
834 }
835 
836 #define ext2_set_bit	__test_and_set_bit_le
837 #define ext2_clear_bit	__test_and_clear_bit_le
838 #define ext2_test_bit	test_bit_le
839 #define ext2_find_first_zero_bit	find_first_zero_bit_le
840 #define ext2_find_next_zero_bit		find_next_zero_bit_le
841