xref: /linux/fs/ext2/ext2.h (revision 6c363eafc4d637ac4bd83d4a7dd06dd3cfbe7c5f)
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 #include <linux/mm.h>
20 #include <linux/highmem.h>
21 
22 /* XXX Here for now... not interested in restructing headers JUST now */
23 
24 /* data type for block offset of block group */
25 typedef int ext2_grpblk_t;
26 
27 /* data type for filesystem-wide blocks number */
28 typedef unsigned long ext2_fsblk_t;
29 
30 #define E2FSBLK "%lu"
31 
32 struct ext2_reserve_window {
33 	ext2_fsblk_t		_rsv_start;	/* First byte reserved */
34 	ext2_fsblk_t		_rsv_end;	/* Last byte reserved or 0 */
35 };
36 
37 struct ext2_reserve_window_node {
38 	struct rb_node	 	rsv_node;
39 	__u32			rsv_goal_size;
40 	__u32			rsv_alloc_hit;
41 	struct ext2_reserve_window	rsv_window;
42 };
43 
44 struct ext2_block_alloc_info {
45 	/* information about reservation window */
46 	struct ext2_reserve_window_node	rsv_window_node;
47 	/*
48 	 * was i_next_alloc_block in ext2_inode_info
49 	 * is the logical (file-relative) number of the
50 	 * most-recently-allocated block in this file.
51 	 * We use this for detecting linearly ascending allocation requests.
52 	 */
53 	__u32			last_alloc_logical_block;
54 	/*
55 	 * Was i_next_alloc_goal in ext2_inode_info
56 	 * is the *physical* companion to i_next_alloc_block.
57 	 * it is the physical block number of the block which was most-recently
58 	 * allocated to this file.  This gives us the goal (target) for the next
59 	 * allocation when we detect linearly ascending requests.
60 	 */
61 	ext2_fsblk_t		last_alloc_physical_block;
62 };
63 
64 #define rsv_start rsv_window._rsv_start
65 #define rsv_end rsv_window._rsv_end
66 
67 struct mb_cache;
68 
69 /*
70  * second extended-fs super-block data in memory
71  */
72 struct ext2_sb_info {
73 	unsigned long s_frag_size;	/* Size of a fragment in bytes */
74 	unsigned long s_frags_per_block;/* Number of fragments per block */
75 	unsigned long s_inodes_per_block;/* Number of inodes per block */
76 	unsigned long s_frags_per_group;/* Number of fragments in a group */
77 	unsigned long s_blocks_per_group;/* Number of blocks in a group */
78 	unsigned long s_inodes_per_group;/* Number of inodes in a group */
79 	unsigned long s_itb_per_group;	/* Number of inode table blocks per group */
80 	unsigned long s_gdb_count;	/* Number of group descriptor blocks */
81 	unsigned long s_desc_per_block;	/* Number of group descriptors per block */
82 	unsigned long s_groups_count;	/* Number of groups in the fs */
83 	unsigned long s_overhead_last;  /* Last calculated overhead */
84 	unsigned long s_blocks_last;    /* Last seen block count */
85 	struct buffer_head * s_sbh;	/* Buffer containing the super block */
86 	struct ext2_super_block * s_es;	/* Pointer to the super block in the buffer */
87 	struct buffer_head ** s_group_desc;
88 	unsigned long  s_mount_opt;
89 	unsigned long s_sb_block;
90 	kuid_t s_resuid;
91 	kgid_t s_resgid;
92 	unsigned short s_mount_state;
93 	unsigned short s_pad;
94 	int s_addr_per_block_bits;
95 	int s_desc_per_block_bits;
96 	int s_inode_size;
97 	int s_first_ino;
98 	spinlock_t s_next_gen_lock;
99 	u32 s_next_generation;
100 	unsigned long s_dir_count;
101 	u8 *s_debts;
102 	struct percpu_counter s_freeblocks_counter;
103 	struct percpu_counter s_freeinodes_counter;
104 	struct percpu_counter s_dirs_counter;
105 	struct blockgroup_lock *s_blockgroup_lock;
106 	/* root of the per fs reservation window tree */
107 	spinlock_t s_rsv_window_lock;
108 	struct rb_root s_rsv_window_root;
109 	struct ext2_reserve_window_node s_rsv_window_head;
110 	/*
111 	 * s_lock protects against concurrent modifications of s_mount_state,
112 	 * s_blocks_last, s_overhead_last and the content of superblock's
113 	 * buffer pointed to by sbi->s_es.
114 	 *
115 	 * Note: It is used in ext2_show_options() to provide a consistent view
116 	 * of the mount options.
117 	 */
118 	spinlock_t s_lock;
119 	struct mb_cache *s_ea_block_cache;
120 	struct dax_device *s_daxdev;
121 };
122 
123 static inline spinlock_t *
124 sb_bgl_lock(struct ext2_sb_info *sbi, unsigned int block_group)
125 {
126 	return bgl_lock_ptr(sbi->s_blockgroup_lock, block_group);
127 }
128 
129 /*
130  * Define EXT2FS_DEBUG to produce debug messages
131  */
132 #undef EXT2FS_DEBUG
133 
134 /*
135  * Define EXT2_RESERVATION to reserve data blocks for expanding files
136  */
137 #define EXT2_DEFAULT_RESERVE_BLOCKS     8
138 /*max window size: 1024(direct blocks) + 3([t,d]indirect blocks) */
139 #define EXT2_MAX_RESERVE_BLOCKS         1027
140 #define EXT2_RESERVE_WINDOW_NOT_ALLOCATED 0
141 /*
142  * The second extended file system version
143  */
144 #define EXT2FS_DATE		"95/08/09"
145 #define EXT2FS_VERSION		"0.5b"
146 
147 /*
148  * Debug code
149  */
150 #ifdef EXT2FS_DEBUG
151 #	define ext2_debug(f, a...)	{ \
152 					printk ("EXT2-fs DEBUG (%s, %d): %s:", \
153 						__FILE__, __LINE__, __func__); \
154 				  	printk (f, ## a); \
155 					}
156 #else
157 #	define ext2_debug(f, a...)	/**/
158 #endif
159 
160 /*
161  * Special inode numbers
162  */
163 #define	EXT2_BAD_INO		 1	/* Bad blocks inode */
164 #define EXT2_ROOT_INO		 2	/* Root inode */
165 #define EXT2_BOOT_LOADER_INO	 5	/* Boot loader inode */
166 #define EXT2_UNDEL_DIR_INO	 6	/* Undelete directory inode */
167 
168 /* First non-reserved inode for old ext2 filesystems */
169 #define EXT2_GOOD_OLD_FIRST_INO	11
170 
171 static inline struct ext2_sb_info *EXT2_SB(struct super_block *sb)
172 {
173 	return sb->s_fs_info;
174 }
175 
176 /*
177  * Macro-instructions used to manage several block sizes
178  */
179 #define EXT2_MIN_BLOCK_SIZE		1024
180 #define	EXT2_MAX_BLOCK_SIZE		4096
181 #define EXT2_MIN_BLOCK_LOG_SIZE		  10
182 #define EXT2_BLOCK_SIZE(s)		((s)->s_blocksize)
183 #define	EXT2_ADDR_PER_BLOCK(s)		(EXT2_BLOCK_SIZE(s) / sizeof (__u32))
184 #define EXT2_BLOCK_SIZE_BITS(s)		((s)->s_blocksize_bits)
185 #define	EXT2_ADDR_PER_BLOCK_BITS(s)	(EXT2_SB(s)->s_addr_per_block_bits)
186 #define EXT2_INODE_SIZE(s)		(EXT2_SB(s)->s_inode_size)
187 #define EXT2_FIRST_INO(s)		(EXT2_SB(s)->s_first_ino)
188 
189 /*
190  * Macro-instructions used to manage fragments
191  */
192 #define EXT2_MIN_FRAG_SIZE		1024
193 #define	EXT2_MAX_FRAG_SIZE		4096
194 #define EXT2_MIN_FRAG_LOG_SIZE		  10
195 #define EXT2_FRAG_SIZE(s)		(EXT2_SB(s)->s_frag_size)
196 #define EXT2_FRAGS_PER_BLOCK(s)		(EXT2_SB(s)->s_frags_per_block)
197 
198 /*
199  * Structure of a blocks group descriptor
200  */
201 struct ext2_group_desc
202 {
203 	__le32	bg_block_bitmap;		/* Blocks bitmap block */
204 	__le32	bg_inode_bitmap;		/* Inodes bitmap block */
205 	__le32	bg_inode_table;		/* Inodes table block */
206 	__le16	bg_free_blocks_count;	/* Free blocks count */
207 	__le16	bg_free_inodes_count;	/* Free inodes count */
208 	__le16	bg_used_dirs_count;	/* Directories count */
209 	__le16	bg_pad;
210 	__le32	bg_reserved[3];
211 };
212 
213 /*
214  * Macro-instructions used to manage group descriptors
215  */
216 #define EXT2_BLOCKS_PER_GROUP(s)	(EXT2_SB(s)->s_blocks_per_group)
217 #define EXT2_DESC_PER_BLOCK(s)		(EXT2_SB(s)->s_desc_per_block)
218 #define EXT2_INODES_PER_GROUP(s)	(EXT2_SB(s)->s_inodes_per_group)
219 #define EXT2_DESC_PER_BLOCK_BITS(s)	(EXT2_SB(s)->s_desc_per_block_bits)
220 
221 /*
222  * Constants relative to the data blocks
223  */
224 #define	EXT2_NDIR_BLOCKS		12
225 #define	EXT2_IND_BLOCK			EXT2_NDIR_BLOCKS
226 #define	EXT2_DIND_BLOCK			(EXT2_IND_BLOCK + 1)
227 #define	EXT2_TIND_BLOCK			(EXT2_DIND_BLOCK + 1)
228 #define	EXT2_N_BLOCKS			(EXT2_TIND_BLOCK + 1)
229 
230 /*
231  * Inode flags (GETFLAGS/SETFLAGS)
232  */
233 #define	EXT2_SECRM_FL			FS_SECRM_FL	/* Secure deletion */
234 #define	EXT2_UNRM_FL			FS_UNRM_FL	/* Undelete */
235 #define	EXT2_COMPR_FL			FS_COMPR_FL	/* Compress file */
236 #define EXT2_SYNC_FL			FS_SYNC_FL	/* Synchronous updates */
237 #define EXT2_IMMUTABLE_FL		FS_IMMUTABLE_FL	/* Immutable file */
238 #define EXT2_APPEND_FL			FS_APPEND_FL	/* writes to file may only append */
239 #define EXT2_NODUMP_FL			FS_NODUMP_FL	/* do not dump file */
240 #define EXT2_NOATIME_FL			FS_NOATIME_FL	/* do not update atime */
241 /* Reserved for compression usage... */
242 #define EXT2_DIRTY_FL			FS_DIRTY_FL
243 #define EXT2_COMPRBLK_FL		FS_COMPRBLK_FL	/* One or more compressed clusters */
244 #define EXT2_NOCOMP_FL			FS_NOCOMP_FL	/* Don't compress */
245 #define EXT2_ECOMPR_FL			FS_ECOMPR_FL	/* Compression error */
246 /* End compression flags --- maybe not all used */
247 #define EXT2_BTREE_FL			FS_BTREE_FL	/* btree format dir */
248 #define EXT2_INDEX_FL			FS_INDEX_FL	/* hash-indexed directory */
249 #define EXT2_IMAGIC_FL			FS_IMAGIC_FL	/* AFS directory */
250 #define EXT2_JOURNAL_DATA_FL		FS_JOURNAL_DATA_FL /* Reserved for ext3 */
251 #define EXT2_NOTAIL_FL			FS_NOTAIL_FL	/* file tail should not be merged */
252 #define EXT2_DIRSYNC_FL			FS_DIRSYNC_FL	/* dirsync behaviour (directories only) */
253 #define EXT2_TOPDIR_FL			FS_TOPDIR_FL	/* Top of directory hierarchies*/
254 #define EXT2_RESERVED_FL		FS_RESERVED_FL	/* reserved for ext2 lib */
255 
256 #define EXT2_FL_USER_VISIBLE		FS_FL_USER_VISIBLE	/* User visible flags */
257 #define EXT2_FL_USER_MODIFIABLE		FS_FL_USER_MODIFIABLE	/* User modifiable flags */
258 
259 /* Flags that should be inherited by new inodes from their parent. */
260 #define EXT2_FL_INHERITED (EXT2_SECRM_FL | EXT2_UNRM_FL | EXT2_COMPR_FL |\
261 			   EXT2_SYNC_FL | EXT2_NODUMP_FL |\
262 			   EXT2_NOATIME_FL | EXT2_COMPRBLK_FL |\
263 			   EXT2_NOCOMP_FL | EXT2_JOURNAL_DATA_FL |\
264 			   EXT2_NOTAIL_FL | EXT2_DIRSYNC_FL)
265 
266 /* Flags that are appropriate for regular files (all but dir-specific ones). */
267 #define EXT2_REG_FLMASK (~(EXT2_DIRSYNC_FL | EXT2_TOPDIR_FL))
268 
269 /* Flags that are appropriate for non-directories/regular files. */
270 #define EXT2_OTHER_FLMASK (EXT2_NODUMP_FL | EXT2_NOATIME_FL)
271 
272 /* Mask out flags that are inappropriate for the given type of inode. */
273 static inline __u32 ext2_mask_flags(umode_t mode, __u32 flags)
274 {
275 	if (S_ISDIR(mode))
276 		return flags;
277 	else if (S_ISREG(mode))
278 		return flags & EXT2_REG_FLMASK;
279 	else
280 		return flags & EXT2_OTHER_FLMASK;
281 }
282 
283 /*
284  * ioctl commands
285  */
286 #define	EXT2_IOC_GETFLAGS		FS_IOC_GETFLAGS
287 #define	EXT2_IOC_SETFLAGS		FS_IOC_SETFLAGS
288 #define	EXT2_IOC_GETVERSION		FS_IOC_GETVERSION
289 #define	EXT2_IOC_SETVERSION		FS_IOC_SETVERSION
290 #define	EXT2_IOC_GETRSVSZ		_IOR('f', 5, long)
291 #define	EXT2_IOC_SETRSVSZ		_IOW('f', 6, long)
292 
293 /*
294  * ioctl commands in 32 bit emulation
295  */
296 #define EXT2_IOC32_GETFLAGS		FS_IOC32_GETFLAGS
297 #define EXT2_IOC32_SETFLAGS		FS_IOC32_SETFLAGS
298 #define EXT2_IOC32_GETVERSION		FS_IOC32_GETVERSION
299 #define EXT2_IOC32_SETVERSION		FS_IOC32_SETVERSION
300 
301 /*
302  * Structure of an inode on the disk
303  */
304 struct ext2_inode {
305 	__le16	i_mode;		/* File mode */
306 	__le16	i_uid;		/* Low 16 bits of Owner Uid */
307 	__le32	i_size;		/* Size in bytes */
308 	__le32	i_atime;	/* Access time */
309 	__le32	i_ctime;	/* Creation time */
310 	__le32	i_mtime;	/* Modification time */
311 	__le32	i_dtime;	/* Deletion Time */
312 	__le16	i_gid;		/* Low 16 bits of Group Id */
313 	__le16	i_links_count;	/* Links count */
314 	__le32	i_blocks;	/* Blocks count */
315 	__le32	i_flags;	/* File flags */
316 	union {
317 		struct {
318 			__le32  l_i_reserved1;
319 		} linux1;
320 		struct {
321 			__le32  h_i_translator;
322 		} hurd1;
323 		struct {
324 			__le32  m_i_reserved1;
325 		} masix1;
326 	} osd1;				/* OS dependent 1 */
327 	__le32	i_block[EXT2_N_BLOCKS];/* Pointers to blocks */
328 	__le32	i_generation;	/* File version (for NFS) */
329 	__le32	i_file_acl;	/* File ACL */
330 	__le32	i_dir_acl;	/* Directory ACL */
331 	__le32	i_faddr;	/* Fragment address */
332 	union {
333 		struct {
334 			__u8	l_i_frag;	/* Fragment number */
335 			__u8	l_i_fsize;	/* Fragment size */
336 			__u16	i_pad1;
337 			__le16	l_i_uid_high;	/* these 2 fields    */
338 			__le16	l_i_gid_high;	/* were reserved2[0] */
339 			__u32	l_i_reserved2;
340 		} linux2;
341 		struct {
342 			__u8	h_i_frag;	/* Fragment number */
343 			__u8	h_i_fsize;	/* Fragment size */
344 			__le16	h_i_mode_high;
345 			__le16	h_i_uid_high;
346 			__le16	h_i_gid_high;
347 			__le32	h_i_author;
348 		} hurd2;
349 		struct {
350 			__u8	m_i_frag;	/* Fragment number */
351 			__u8	m_i_fsize;	/* Fragment size */
352 			__u16	m_pad1;
353 			__u32	m_i_reserved2[2];
354 		} masix2;
355 	} osd2;				/* OS dependent 2 */
356 };
357 
358 #define i_size_high	i_dir_acl
359 
360 #define i_reserved1	osd1.linux1.l_i_reserved1
361 #define i_frag		osd2.linux2.l_i_frag
362 #define i_fsize		osd2.linux2.l_i_fsize
363 #define i_uid_low	i_uid
364 #define i_gid_low	i_gid
365 #define i_uid_high	osd2.linux2.l_i_uid_high
366 #define i_gid_high	osd2.linux2.l_i_gid_high
367 #define i_reserved2	osd2.linux2.l_i_reserved2
368 
369 /*
370  * File system states
371  */
372 #define	EXT2_VALID_FS			0x0001	/* Unmounted cleanly */
373 #define	EXT2_ERROR_FS			0x0002	/* Errors detected */
374 #define	EFSCORRUPTED			EUCLEAN	/* Filesystem is corrupted */
375 
376 /*
377  * Mount flags
378  */
379 #define EXT2_MOUNT_OLDALLOC		0x000002  /* Don't use the new Orlov allocator */
380 #define EXT2_MOUNT_GRPID		0x000004  /* Create files with directory's group */
381 #define EXT2_MOUNT_DEBUG		0x000008  /* Some debugging messages */
382 #define EXT2_MOUNT_ERRORS_CONT		0x000010  /* Continue on errors */
383 #define EXT2_MOUNT_ERRORS_RO		0x000020  /* Remount fs ro on errors */
384 #define EXT2_MOUNT_ERRORS_PANIC		0x000040  /* Panic on errors */
385 #define EXT2_MOUNT_MINIX_DF		0x000080  /* Mimics the Minix statfs */
386 #define EXT2_MOUNT_NOBH			0x000100  /* No buffer_heads */
387 #define EXT2_MOUNT_NO_UID32		0x000200  /* Disable 32-bit UIDs */
388 #define EXT2_MOUNT_XATTR_USER		0x004000  /* Extended user attributes */
389 #define EXT2_MOUNT_POSIX_ACL		0x008000  /* POSIX Access Control Lists */
390 #define EXT2_MOUNT_XIP			0x010000  /* Obsolete, use DAX */
391 #define EXT2_MOUNT_USRQUOTA		0x020000  /* user quota */
392 #define EXT2_MOUNT_GRPQUOTA		0x040000  /* group quota */
393 #define EXT2_MOUNT_RESERVATION		0x080000  /* Preallocation */
394 #define EXT2_MOUNT_DAX			0x100000  /* Direct Access */
395 
396 
397 #define clear_opt(o, opt)		o &= ~EXT2_MOUNT_##opt
398 #define set_opt(o, opt)			o |= EXT2_MOUNT_##opt
399 #define test_opt(sb, opt)		(EXT2_SB(sb)->s_mount_opt & \
400 					 EXT2_MOUNT_##opt)
401 /*
402  * Maximal mount counts between two filesystem checks
403  */
404 #define EXT2_DFL_MAX_MNT_COUNT		20	/* Allow 20 mounts */
405 #define EXT2_DFL_CHECKINTERVAL		0	/* Don't use interval check */
406 
407 /*
408  * Behaviour when detecting errors
409  */
410 #define EXT2_ERRORS_CONTINUE		1	/* Continue execution */
411 #define EXT2_ERRORS_RO			2	/* Remount fs read-only */
412 #define EXT2_ERRORS_PANIC		3	/* Panic */
413 #define EXT2_ERRORS_DEFAULT		EXT2_ERRORS_CONTINUE
414 
415 /*
416  * Structure of the super block
417  */
418 struct ext2_super_block {
419 	__le32	s_inodes_count;		/* Inodes count */
420 	__le32	s_blocks_count;		/* Blocks count */
421 	__le32	s_r_blocks_count;	/* Reserved blocks count */
422 	__le32	s_free_blocks_count;	/* Free blocks count */
423 	__le32	s_free_inodes_count;	/* Free inodes count */
424 	__le32	s_first_data_block;	/* First Data Block */
425 	__le32	s_log_block_size;	/* Block size */
426 	__le32	s_log_frag_size;	/* Fragment size */
427 	__le32	s_blocks_per_group;	/* # Blocks per group */
428 	__le32	s_frags_per_group;	/* # Fragments per group */
429 	__le32	s_inodes_per_group;	/* # Inodes per group */
430 	__le32	s_mtime;		/* Mount time */
431 	__le32	s_wtime;		/* Write time */
432 	__le16	s_mnt_count;		/* Mount count */
433 	__le16	s_max_mnt_count;	/* Maximal mount count */
434 	__le16	s_magic;		/* Magic signature */
435 	__le16	s_state;		/* File system state */
436 	__le16	s_errors;		/* Behaviour when detecting errors */
437 	__le16	s_minor_rev_level; 	/* minor revision level */
438 	__le32	s_lastcheck;		/* time of last check */
439 	__le32	s_checkinterval;	/* max. time between checks */
440 	__le32	s_creator_os;		/* OS */
441 	__le32	s_rev_level;		/* Revision level */
442 	__le16	s_def_resuid;		/* Default uid for reserved blocks */
443 	__le16	s_def_resgid;		/* Default gid for reserved blocks */
444 	/*
445 	 * These fields are for EXT2_DYNAMIC_REV superblocks only.
446 	 *
447 	 * Note: the difference between the compatible feature set and
448 	 * the incompatible feature set is that if there is a bit set
449 	 * in the incompatible feature set that the kernel doesn't
450 	 * know about, it should refuse to mount the filesystem.
451 	 *
452 	 * e2fsck's requirements are more strict; if it doesn't know
453 	 * about a feature in either the compatible or incompatible
454 	 * feature set, it must abort and not try to meddle with
455 	 * things it doesn't understand...
456 	 */
457 	__le32	s_first_ino; 		/* First non-reserved inode */
458 	__le16   s_inode_size; 		/* size of inode structure */
459 	__le16	s_block_group_nr; 	/* block group # of this superblock */
460 	__le32	s_feature_compat; 	/* compatible feature set */
461 	__le32	s_feature_incompat; 	/* incompatible feature set */
462 	__le32	s_feature_ro_compat; 	/* readonly-compatible feature set */
463 	__u8	s_uuid[16];		/* 128-bit uuid for volume */
464 	char	s_volume_name[16]; 	/* volume name */
465 	char	s_last_mounted[64]; 	/* directory where last mounted */
466 	__le32	s_algorithm_usage_bitmap; /* For compression */
467 	/*
468 	 * Performance hints.  Directory preallocation should only
469 	 * happen if the EXT2_COMPAT_PREALLOC flag is on.
470 	 */
471 	__u8	s_prealloc_blocks;	/* Nr of blocks to try to preallocate*/
472 	__u8	s_prealloc_dir_blocks;	/* Nr to preallocate for dirs */
473 	__u16	s_padding1;
474 	/*
475 	 * Journaling support valid if EXT3_FEATURE_COMPAT_HAS_JOURNAL set.
476 	 */
477 	__u8	s_journal_uuid[16];	/* uuid of journal superblock */
478 	__u32	s_journal_inum;		/* inode number of journal file */
479 	__u32	s_journal_dev;		/* device number of journal file */
480 	__u32	s_last_orphan;		/* start of list of inodes to delete */
481 	__u32	s_hash_seed[4];		/* HTREE hash seed */
482 	__u8	s_def_hash_version;	/* Default hash version to use */
483 	__u8	s_reserved_char_pad;
484 	__u16	s_reserved_word_pad;
485 	__le32	s_default_mount_opts;
486  	__le32	s_first_meta_bg; 	/* First metablock block group */
487 	__u32	s_reserved[190];	/* Padding to the end of the block */
488 };
489 
490 /*
491  * Codes for operating systems
492  */
493 #define EXT2_OS_LINUX		0
494 #define EXT2_OS_HURD		1
495 #define EXT2_OS_MASIX		2
496 #define EXT2_OS_FREEBSD		3
497 #define EXT2_OS_LITES		4
498 
499 /*
500  * Revision levels
501  */
502 #define EXT2_GOOD_OLD_REV	0	/* The good old (original) format */
503 #define EXT2_DYNAMIC_REV	1 	/* V2 format w/ dynamic inode sizes */
504 
505 #define EXT2_CURRENT_REV	EXT2_GOOD_OLD_REV
506 #define EXT2_MAX_SUPP_REV	EXT2_DYNAMIC_REV
507 
508 #define EXT2_GOOD_OLD_INODE_SIZE 128
509 
510 /*
511  * Feature set definitions
512  */
513 
514 #define EXT2_HAS_COMPAT_FEATURE(sb,mask)			\
515 	( EXT2_SB(sb)->s_es->s_feature_compat & cpu_to_le32(mask) )
516 #define EXT2_HAS_RO_COMPAT_FEATURE(sb,mask)			\
517 	( EXT2_SB(sb)->s_es->s_feature_ro_compat & cpu_to_le32(mask) )
518 #define EXT2_HAS_INCOMPAT_FEATURE(sb,mask)			\
519 	( EXT2_SB(sb)->s_es->s_feature_incompat & cpu_to_le32(mask) )
520 #define EXT2_SET_COMPAT_FEATURE(sb,mask)			\
521 	EXT2_SB(sb)->s_es->s_feature_compat |= cpu_to_le32(mask)
522 #define EXT2_SET_RO_COMPAT_FEATURE(sb,mask)			\
523 	EXT2_SB(sb)->s_es->s_feature_ro_compat |= cpu_to_le32(mask)
524 #define EXT2_SET_INCOMPAT_FEATURE(sb,mask)			\
525 	EXT2_SB(sb)->s_es->s_feature_incompat |= cpu_to_le32(mask)
526 #define EXT2_CLEAR_COMPAT_FEATURE(sb,mask)			\
527 	EXT2_SB(sb)->s_es->s_feature_compat &= ~cpu_to_le32(mask)
528 #define EXT2_CLEAR_RO_COMPAT_FEATURE(sb,mask)			\
529 	EXT2_SB(sb)->s_es->s_feature_ro_compat &= ~cpu_to_le32(mask)
530 #define EXT2_CLEAR_INCOMPAT_FEATURE(sb,mask)			\
531 	EXT2_SB(sb)->s_es->s_feature_incompat &= ~cpu_to_le32(mask)
532 
533 #define EXT2_FEATURE_COMPAT_DIR_PREALLOC	0x0001
534 #define EXT2_FEATURE_COMPAT_IMAGIC_INODES	0x0002
535 #define EXT3_FEATURE_COMPAT_HAS_JOURNAL		0x0004
536 #define EXT2_FEATURE_COMPAT_EXT_ATTR		0x0008
537 #define EXT2_FEATURE_COMPAT_RESIZE_INO		0x0010
538 #define EXT2_FEATURE_COMPAT_DIR_INDEX		0x0020
539 #define EXT2_FEATURE_COMPAT_ANY			0xffffffff
540 
541 #define EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER	0x0001
542 #define EXT2_FEATURE_RO_COMPAT_LARGE_FILE	0x0002
543 #define EXT2_FEATURE_RO_COMPAT_BTREE_DIR	0x0004
544 #define EXT2_FEATURE_RO_COMPAT_ANY		0xffffffff
545 
546 #define EXT2_FEATURE_INCOMPAT_COMPRESSION	0x0001
547 #define EXT2_FEATURE_INCOMPAT_FILETYPE		0x0002
548 #define EXT3_FEATURE_INCOMPAT_RECOVER		0x0004
549 #define EXT3_FEATURE_INCOMPAT_JOURNAL_DEV	0x0008
550 #define EXT2_FEATURE_INCOMPAT_META_BG		0x0010
551 #define EXT2_FEATURE_INCOMPAT_ANY		0xffffffff
552 
553 #define EXT2_FEATURE_COMPAT_SUPP	EXT2_FEATURE_COMPAT_EXT_ATTR
554 #define EXT2_FEATURE_INCOMPAT_SUPP	(EXT2_FEATURE_INCOMPAT_FILETYPE| \
555 					 EXT2_FEATURE_INCOMPAT_META_BG)
556 #define EXT2_FEATURE_RO_COMPAT_SUPP	(EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER| \
557 					 EXT2_FEATURE_RO_COMPAT_LARGE_FILE| \
558 					 EXT2_FEATURE_RO_COMPAT_BTREE_DIR)
559 #define EXT2_FEATURE_RO_COMPAT_UNSUPPORTED	~EXT2_FEATURE_RO_COMPAT_SUPP
560 #define EXT2_FEATURE_INCOMPAT_UNSUPPORTED	~EXT2_FEATURE_INCOMPAT_SUPP
561 
562 /*
563  * Default values for user and/or group using reserved blocks
564  */
565 #define	EXT2_DEF_RESUID		0
566 #define	EXT2_DEF_RESGID		0
567 
568 /*
569  * Default mount options
570  */
571 #define EXT2_DEFM_DEBUG		0x0001
572 #define EXT2_DEFM_BSDGROUPS	0x0002
573 #define EXT2_DEFM_XATTR_USER	0x0004
574 #define EXT2_DEFM_ACL		0x0008
575 #define EXT2_DEFM_UID16		0x0010
576     /* Not used by ext2, but reserved for use by ext3 */
577 #define EXT3_DEFM_JMODE		0x0060
578 #define EXT3_DEFM_JMODE_DATA	0x0020
579 #define EXT3_DEFM_JMODE_ORDERED	0x0040
580 #define EXT3_DEFM_JMODE_WBACK	0x0060
581 
582 /*
583  * Structure of a directory entry
584  */
585 
586 struct ext2_dir_entry {
587 	__le32	inode;			/* Inode number */
588 	__le16	rec_len;		/* Directory entry length */
589 	__le16	name_len;		/* Name length */
590 	char	name[];			/* File name, up to EXT2_NAME_LEN */
591 };
592 
593 /*
594  * The new version of the directory entry.  Since EXT2 structures are
595  * stored in intel byte order, and the name_len field could never be
596  * bigger than 255 chars, it's safe to reclaim the extra byte for the
597  * file_type field.
598  */
599 struct ext2_dir_entry_2 {
600 	__le32	inode;			/* Inode number */
601 	__le16	rec_len;		/* Directory entry length */
602 	__u8	name_len;		/* Name length */
603 	__u8	file_type;
604 	char	name[];			/* File name, up to EXT2_NAME_LEN */
605 };
606 
607 /*
608  * EXT2_DIR_PAD defines the directory entries boundaries
609  *
610  * NOTE: It must be a multiple of 4
611  */
612 #define EXT2_DIR_PAD		 	4
613 #define EXT2_DIR_ROUND 			(EXT2_DIR_PAD - 1)
614 #define EXT2_DIR_REC_LEN(name_len)	(((name_len) + 8 + EXT2_DIR_ROUND) & \
615 					 ~EXT2_DIR_ROUND)
616 #define EXT2_MAX_REC_LEN		((1<<16)-1)
617 
618 static inline void verify_offsets(void)
619 {
620 #define A(x,y) BUILD_BUG_ON(x != offsetof(struct ext2_super_block, y));
621 	A(EXT2_SB_MAGIC_OFFSET, s_magic);
622 	A(EXT2_SB_BLOCKS_OFFSET, s_blocks_count);
623 	A(EXT2_SB_BSIZE_OFFSET, s_log_block_size);
624 #undef A
625 }
626 
627 /*
628  * ext2 mount options
629  */
630 struct ext2_mount_options {
631 	unsigned long s_mount_opt;
632 	kuid_t s_resuid;
633 	kgid_t s_resgid;
634 };
635 
636 /*
637  * second extended file system inode data in memory
638  */
639 struct ext2_inode_info {
640 	__le32	i_data[15];
641 	__u32	i_flags;
642 	__u32	i_faddr;
643 	__u8	i_frag_no;
644 	__u8	i_frag_size;
645 	__u16	i_state;
646 	__u32	i_file_acl;
647 	__u32	i_dir_acl;
648 	__u32	i_dtime;
649 
650 	/*
651 	 * i_block_group is the number of the block group which contains
652 	 * this file's inode.  Constant across the lifetime of the inode,
653 	 * it is used for making block allocation decisions - we try to
654 	 * place a file's data blocks near its inode block, and new inodes
655 	 * near to their parent directory's inode.
656 	 */
657 	__u32	i_block_group;
658 
659 	/* block reservation info */
660 	struct ext2_block_alloc_info *i_block_alloc_info;
661 
662 	__u32	i_dir_start_lookup;
663 #ifdef CONFIG_EXT2_FS_XATTR
664 	/*
665 	 * Extended attributes can be read independently of the main file
666 	 * data. Taking i_mutex even when reading would cause contention
667 	 * between readers of EAs and writers of regular file data, so
668 	 * instead we synchronize on xattr_sem when reading or changing
669 	 * EAs.
670 	 */
671 	struct rw_semaphore xattr_sem;
672 #endif
673 	rwlock_t i_meta_lock;
674 #ifdef CONFIG_FS_DAX
675 	struct rw_semaphore dax_sem;
676 #endif
677 
678 	/*
679 	 * truncate_mutex is for serialising ext2_truncate() against
680 	 * ext2_getblock().  It also protects the internals of the inode's
681 	 * reservation data structures: ext2_reserve_window and
682 	 * ext2_reserve_window_node.
683 	 */
684 	struct mutex truncate_mutex;
685 	struct inode	vfs_inode;
686 	struct list_head i_orphan;	/* unlinked but open inodes */
687 #ifdef CONFIG_QUOTA
688 	struct dquot *i_dquot[MAXQUOTAS];
689 #endif
690 };
691 
692 #ifdef CONFIG_FS_DAX
693 #define dax_sem_down_write(ext2_inode)	down_write(&(ext2_inode)->dax_sem)
694 #define dax_sem_up_write(ext2_inode)	up_write(&(ext2_inode)->dax_sem)
695 #else
696 #define dax_sem_down_write(ext2_inode)
697 #define dax_sem_up_write(ext2_inode)
698 #endif
699 
700 /*
701  * Inode dynamic state flags
702  */
703 #define EXT2_STATE_NEW			0x00000001 /* inode is newly created */
704 
705 
706 /*
707  * Function prototypes
708  */
709 
710 /*
711  * Ok, these declarations are also in <linux/kernel.h> but none of the
712  * ext2 source programs needs to include it so they are duplicated here.
713  */
714 
715 static inline struct ext2_inode_info *EXT2_I(struct inode *inode)
716 {
717 	return container_of(inode, struct ext2_inode_info, vfs_inode);
718 }
719 
720 /* balloc.c */
721 extern int ext2_bg_has_super(struct super_block *sb, int group);
722 extern unsigned long ext2_bg_num_gdb(struct super_block *sb, int group);
723 extern ext2_fsblk_t ext2_new_block(struct inode *, unsigned long, int *);
724 extern ext2_fsblk_t ext2_new_blocks(struct inode *, unsigned long,
725 				unsigned long *, int *);
726 extern int ext2_data_block_valid(struct ext2_sb_info *sbi, ext2_fsblk_t start_blk,
727 				 unsigned int count);
728 extern void ext2_free_blocks (struct inode *, unsigned long,
729 			      unsigned long);
730 extern unsigned long ext2_count_free_blocks (struct super_block *);
731 extern unsigned long ext2_count_dirs (struct super_block *);
732 extern struct ext2_group_desc * ext2_get_group_desc(struct super_block * sb,
733 						    unsigned int block_group,
734 						    struct buffer_head ** bh);
735 extern void ext2_discard_reservation (struct inode *);
736 extern int ext2_should_retry_alloc(struct super_block *sb, int *retries);
737 extern void ext2_init_block_alloc_info(struct inode *);
738 extern void ext2_rsv_window_add(struct super_block *sb, struct ext2_reserve_window_node *rsv);
739 
740 /* dir.c */
741 extern int ext2_add_link (struct dentry *, struct inode *);
742 extern int ext2_inode_by_name(struct inode *dir,
743 			      const struct qstr *child, ino_t *ino);
744 extern int ext2_make_empty(struct inode *, struct inode *);
745 extern struct ext2_dir_entry_2 * ext2_find_entry (struct inode *,const struct qstr *, struct page **);
746 extern int ext2_delete_entry (struct ext2_dir_entry_2 *, struct page *);
747 extern int ext2_empty_dir (struct inode *);
748 extern struct ext2_dir_entry_2 * ext2_dotdot (struct inode *, struct page **);
749 extern void ext2_set_link(struct inode *, struct ext2_dir_entry_2 *, struct page *, struct inode *, int);
750 static inline void ext2_put_page(struct page *page)
751 {
752 	kunmap(page);
753 	put_page(page);
754 }
755 
756 /* ialloc.c */
757 extern struct inode * ext2_new_inode (struct inode *, umode_t, const struct qstr *);
758 extern void ext2_free_inode (struct inode *);
759 extern unsigned long ext2_count_free_inodes (struct super_block *);
760 extern unsigned long ext2_count_free (struct buffer_head *, unsigned);
761 
762 /* inode.c */
763 extern struct inode *ext2_iget (struct super_block *, unsigned long);
764 extern int ext2_write_inode (struct inode *, struct writeback_control *);
765 extern void ext2_evict_inode(struct inode *);
766 extern int ext2_get_block(struct inode *, sector_t, struct buffer_head *, int);
767 extern int ext2_setattr (struct user_namespace *, struct dentry *, struct iattr *);
768 extern int ext2_getattr (struct user_namespace *, const struct path *,
769 			 struct kstat *, u32, unsigned int);
770 extern void ext2_set_inode_flags(struct inode *inode);
771 extern int ext2_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
772 		       u64 start, u64 len);
773 
774 /* ioctl.c */
775 extern long ext2_ioctl(struct file *, unsigned int, unsigned long);
776 extern long ext2_compat_ioctl(struct file *, unsigned int, unsigned long);
777 
778 /* namei.c */
779 struct dentry *ext2_get_parent(struct dentry *child);
780 
781 /* super.c */
782 extern __printf(3, 4)
783 void ext2_error(struct super_block *, const char *, const char *, ...);
784 extern __printf(3, 4)
785 void ext2_msg(struct super_block *, const char *, const char *, ...);
786 extern void ext2_update_dynamic_rev (struct super_block *sb);
787 extern void ext2_sync_super(struct super_block *sb, struct ext2_super_block *es,
788 			    int wait);
789 
790 /*
791  * Inodes and files operations
792  */
793 
794 /* dir.c */
795 extern const struct file_operations ext2_dir_operations;
796 
797 /* file.c */
798 extern int ext2_fsync(struct file *file, loff_t start, loff_t end,
799 		      int datasync);
800 extern const struct inode_operations ext2_file_inode_operations;
801 extern const struct file_operations ext2_file_operations;
802 
803 /* inode.c */
804 extern void ext2_set_file_ops(struct inode *inode);
805 extern const struct address_space_operations ext2_aops;
806 extern const struct address_space_operations ext2_nobh_aops;
807 extern const struct iomap_ops ext2_iomap_ops;
808 
809 /* namei.c */
810 extern const struct inode_operations ext2_dir_inode_operations;
811 extern const struct inode_operations ext2_special_inode_operations;
812 
813 /* symlink.c */
814 extern const struct inode_operations ext2_fast_symlink_inode_operations;
815 extern const struct inode_operations ext2_symlink_inode_operations;
816 
817 static inline ext2_fsblk_t
818 ext2_group_first_block_no(struct super_block *sb, unsigned long group_no)
819 {
820 	return group_no * (ext2_fsblk_t)EXT2_BLOCKS_PER_GROUP(sb) +
821 		le32_to_cpu(EXT2_SB(sb)->s_es->s_first_data_block);
822 }
823 
824 static inline ext2_fsblk_t
825 ext2_group_last_block_no(struct super_block *sb, unsigned long group_no)
826 {
827 	struct ext2_sb_info *sbi = EXT2_SB(sb);
828 
829 	if (group_no == sbi->s_groups_count - 1)
830 		return le32_to_cpu(sbi->s_es->s_blocks_count) - 1;
831 	else
832 		return ext2_group_first_block_no(sb, group_no) +
833 			EXT2_BLOCKS_PER_GROUP(sb) - 1;
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