xref: /openbmc/linux/fs/ext2/ext2.h (revision fe0a5788)
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 is the physical block number of the block which was most-recently
56 	 * allocated to this file.  This gives 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_OLDALLOC		0x000002  /* Don't use the new Orlov allocator */
378 #define EXT2_MOUNT_GRPID		0x000004  /* Create files with directory's group */
379 #define EXT2_MOUNT_DEBUG		0x000008  /* Some debugging messages */
380 #define EXT2_MOUNT_ERRORS_CONT		0x000010  /* Continue on errors */
381 #define EXT2_MOUNT_ERRORS_RO		0x000020  /* Remount fs ro on errors */
382 #define EXT2_MOUNT_ERRORS_PANIC		0x000040  /* Panic on errors */
383 #define EXT2_MOUNT_MINIX_DF		0x000080  /* Mimics the Minix statfs */
384 #define EXT2_MOUNT_NOBH			0x000100  /* No buffer_heads */
385 #define EXT2_MOUNT_NO_UID32		0x000200  /* Disable 32-bit UIDs */
386 #define EXT2_MOUNT_XATTR_USER		0x004000  /* Extended user attributes */
387 #define EXT2_MOUNT_POSIX_ACL		0x008000  /* POSIX Access Control Lists */
388 #define EXT2_MOUNT_XIP			0x010000  /* Obsolete, use DAX */
389 #define EXT2_MOUNT_USRQUOTA		0x020000  /* user quota */
390 #define EXT2_MOUNT_GRPQUOTA		0x040000  /* group quota */
391 #define EXT2_MOUNT_RESERVATION		0x080000  /* Preallocation */
392 #define EXT2_MOUNT_DAX			0x100000  /* Direct Access */
393 
394 
395 #define clear_opt(o, opt)		o &= ~EXT2_MOUNT_##opt
396 #define set_opt(o, opt)			o |= EXT2_MOUNT_##opt
397 #define test_opt(sb, opt)		(EXT2_SB(sb)->s_mount_opt & \
398 					 EXT2_MOUNT_##opt)
399 /*
400  * Maximal mount counts between two filesystem checks
401  */
402 #define EXT2_DFL_MAX_MNT_COUNT		20	/* Allow 20 mounts */
403 #define EXT2_DFL_CHECKINTERVAL		0	/* Don't use interval check */
404 
405 /*
406  * Behaviour when detecting errors
407  */
408 #define EXT2_ERRORS_CONTINUE		1	/* Continue execution */
409 #define EXT2_ERRORS_RO			2	/* Remount fs read-only */
410 #define EXT2_ERRORS_PANIC		3	/* Panic */
411 #define EXT2_ERRORS_DEFAULT		EXT2_ERRORS_CONTINUE
412 
413 /*
414  * Structure of the super block
415  */
416 struct ext2_super_block {
417 	__le32	s_inodes_count;		/* Inodes count */
418 	__le32	s_blocks_count;		/* Blocks count */
419 	__le32	s_r_blocks_count;	/* Reserved blocks count */
420 	__le32	s_free_blocks_count;	/* Free blocks count */
421 	__le32	s_free_inodes_count;	/* Free inodes count */
422 	__le32	s_first_data_block;	/* First Data Block */
423 	__le32	s_log_block_size;	/* Block size */
424 	__le32	s_log_frag_size;	/* Fragment size */
425 	__le32	s_blocks_per_group;	/* # Blocks per group */
426 	__le32	s_frags_per_group;	/* # Fragments per group */
427 	__le32	s_inodes_per_group;	/* # Inodes per group */
428 	__le32	s_mtime;		/* Mount time */
429 	__le32	s_wtime;		/* Write time */
430 	__le16	s_mnt_count;		/* Mount count */
431 	__le16	s_max_mnt_count;	/* Maximal mount count */
432 	__le16	s_magic;		/* Magic signature */
433 	__le16	s_state;		/* File system state */
434 	__le16	s_errors;		/* Behaviour when detecting errors */
435 	__le16	s_minor_rev_level; 	/* minor revision level */
436 	__le32	s_lastcheck;		/* time of last check */
437 	__le32	s_checkinterval;	/* max. time between checks */
438 	__le32	s_creator_os;		/* OS */
439 	__le32	s_rev_level;		/* Revision level */
440 	__le16	s_def_resuid;		/* Default uid for reserved blocks */
441 	__le16	s_def_resgid;		/* Default gid for reserved blocks */
442 	/*
443 	 * These fields are for EXT2_DYNAMIC_REV superblocks only.
444 	 *
445 	 * Note: the difference between the compatible feature set and
446 	 * the incompatible feature set is that if there is a bit set
447 	 * in the incompatible feature set that the kernel doesn't
448 	 * know about, it should refuse to mount the filesystem.
449 	 *
450 	 * e2fsck's requirements are more strict; if it doesn't know
451 	 * about a feature in either the compatible or incompatible
452 	 * feature set, it must abort and not try to meddle with
453 	 * things it doesn't understand...
454 	 */
455 	__le32	s_first_ino; 		/* First non-reserved inode */
456 	__le16   s_inode_size; 		/* size of inode structure */
457 	__le16	s_block_group_nr; 	/* block group # of this superblock */
458 	__le32	s_feature_compat; 	/* compatible feature set */
459 	__le32	s_feature_incompat; 	/* incompatible feature set */
460 	__le32	s_feature_ro_compat; 	/* readonly-compatible feature set */
461 	__u8	s_uuid[16];		/* 128-bit uuid for volume */
462 	char	s_volume_name[16]; 	/* volume name */
463 	char	s_last_mounted[64]; 	/* directory where last mounted */
464 	__le32	s_algorithm_usage_bitmap; /* For compression */
465 	/*
466 	 * Performance hints.  Directory preallocation should only
467 	 * happen if the EXT2_COMPAT_PREALLOC flag is on.
468 	 */
469 	__u8	s_prealloc_blocks;	/* Nr of blocks to try to preallocate*/
470 	__u8	s_prealloc_dir_blocks;	/* Nr to preallocate for dirs */
471 	__u16	s_padding1;
472 	/*
473 	 * Journaling support valid if EXT3_FEATURE_COMPAT_HAS_JOURNAL set.
474 	 */
475 	__u8	s_journal_uuid[16];	/* uuid of journal superblock */
476 	__u32	s_journal_inum;		/* inode number of journal file */
477 	__u32	s_journal_dev;		/* device number of journal file */
478 	__u32	s_last_orphan;		/* start of list of inodes to delete */
479 	__u32	s_hash_seed[4];		/* HTREE hash seed */
480 	__u8	s_def_hash_version;	/* Default hash version to use */
481 	__u8	s_reserved_char_pad;
482 	__u16	s_reserved_word_pad;
483 	__le32	s_default_mount_opts;
484  	__le32	s_first_meta_bg; 	/* First metablock block group */
485 	__u32	s_reserved[190];	/* Padding to the end of the block */
486 };
487 
488 /*
489  * Codes for operating systems
490  */
491 #define EXT2_OS_LINUX		0
492 #define EXT2_OS_HURD		1
493 #define EXT2_OS_MASIX		2
494 #define EXT2_OS_FREEBSD		3
495 #define EXT2_OS_LITES		4
496 
497 /*
498  * Revision levels
499  */
500 #define EXT2_GOOD_OLD_REV	0	/* The good old (original) format */
501 #define EXT2_DYNAMIC_REV	1 	/* V2 format w/ dynamic inode sizes */
502 
503 #define EXT2_CURRENT_REV	EXT2_GOOD_OLD_REV
504 #define EXT2_MAX_SUPP_REV	EXT2_DYNAMIC_REV
505 
506 #define EXT2_GOOD_OLD_INODE_SIZE 128
507 
508 /*
509  * Feature set definitions
510  */
511 
512 #define EXT2_HAS_COMPAT_FEATURE(sb,mask)			\
513 	( EXT2_SB(sb)->s_es->s_feature_compat & cpu_to_le32(mask) )
514 #define EXT2_HAS_RO_COMPAT_FEATURE(sb,mask)			\
515 	( EXT2_SB(sb)->s_es->s_feature_ro_compat & cpu_to_le32(mask) )
516 #define EXT2_HAS_INCOMPAT_FEATURE(sb,mask)			\
517 	( EXT2_SB(sb)->s_es->s_feature_incompat & cpu_to_le32(mask) )
518 #define EXT2_SET_COMPAT_FEATURE(sb,mask)			\
519 	EXT2_SB(sb)->s_es->s_feature_compat |= cpu_to_le32(mask)
520 #define EXT2_SET_RO_COMPAT_FEATURE(sb,mask)			\
521 	EXT2_SB(sb)->s_es->s_feature_ro_compat |= cpu_to_le32(mask)
522 #define EXT2_SET_INCOMPAT_FEATURE(sb,mask)			\
523 	EXT2_SB(sb)->s_es->s_feature_incompat |= cpu_to_le32(mask)
524 #define EXT2_CLEAR_COMPAT_FEATURE(sb,mask)			\
525 	EXT2_SB(sb)->s_es->s_feature_compat &= ~cpu_to_le32(mask)
526 #define EXT2_CLEAR_RO_COMPAT_FEATURE(sb,mask)			\
527 	EXT2_SB(sb)->s_es->s_feature_ro_compat &= ~cpu_to_le32(mask)
528 #define EXT2_CLEAR_INCOMPAT_FEATURE(sb,mask)			\
529 	EXT2_SB(sb)->s_es->s_feature_incompat &= ~cpu_to_le32(mask)
530 
531 #define EXT2_FEATURE_COMPAT_DIR_PREALLOC	0x0001
532 #define EXT2_FEATURE_COMPAT_IMAGIC_INODES	0x0002
533 #define EXT3_FEATURE_COMPAT_HAS_JOURNAL		0x0004
534 #define EXT2_FEATURE_COMPAT_EXT_ATTR		0x0008
535 #define EXT2_FEATURE_COMPAT_RESIZE_INO		0x0010
536 #define EXT2_FEATURE_COMPAT_DIR_INDEX		0x0020
537 #define EXT2_FEATURE_COMPAT_ANY			0xffffffff
538 
539 #define EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER	0x0001
540 #define EXT2_FEATURE_RO_COMPAT_LARGE_FILE	0x0002
541 #define EXT2_FEATURE_RO_COMPAT_BTREE_DIR	0x0004
542 #define EXT2_FEATURE_RO_COMPAT_ANY		0xffffffff
543 
544 #define EXT2_FEATURE_INCOMPAT_COMPRESSION	0x0001
545 #define EXT2_FEATURE_INCOMPAT_FILETYPE		0x0002
546 #define EXT3_FEATURE_INCOMPAT_RECOVER		0x0004
547 #define EXT3_FEATURE_INCOMPAT_JOURNAL_DEV	0x0008
548 #define EXT2_FEATURE_INCOMPAT_META_BG		0x0010
549 #define EXT2_FEATURE_INCOMPAT_ANY		0xffffffff
550 
551 #define EXT2_FEATURE_COMPAT_SUPP	EXT2_FEATURE_COMPAT_EXT_ATTR
552 #define EXT2_FEATURE_INCOMPAT_SUPP	(EXT2_FEATURE_INCOMPAT_FILETYPE| \
553 					 EXT2_FEATURE_INCOMPAT_META_BG)
554 #define EXT2_FEATURE_RO_COMPAT_SUPP	(EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER| \
555 					 EXT2_FEATURE_RO_COMPAT_LARGE_FILE| \
556 					 EXT2_FEATURE_RO_COMPAT_BTREE_DIR)
557 #define EXT2_FEATURE_RO_COMPAT_UNSUPPORTED	~EXT2_FEATURE_RO_COMPAT_SUPP
558 #define EXT2_FEATURE_INCOMPAT_UNSUPPORTED	~EXT2_FEATURE_INCOMPAT_SUPP
559 
560 /*
561  * Default values for user and/or group using reserved blocks
562  */
563 #define	EXT2_DEF_RESUID		0
564 #define	EXT2_DEF_RESGID		0
565 
566 /*
567  * Default mount options
568  */
569 #define EXT2_DEFM_DEBUG		0x0001
570 #define EXT2_DEFM_BSDGROUPS	0x0002
571 #define EXT2_DEFM_XATTR_USER	0x0004
572 #define EXT2_DEFM_ACL		0x0008
573 #define EXT2_DEFM_UID16		0x0010
574     /* Not used by ext2, but reserved for use by ext3 */
575 #define EXT3_DEFM_JMODE		0x0060
576 #define EXT3_DEFM_JMODE_DATA	0x0020
577 #define EXT3_DEFM_JMODE_ORDERED	0x0040
578 #define EXT3_DEFM_JMODE_WBACK	0x0060
579 
580 /*
581  * Structure of a directory entry
582  */
583 
584 struct ext2_dir_entry {
585 	__le32	inode;			/* Inode number */
586 	__le16	rec_len;		/* Directory entry length */
587 	__le16	name_len;		/* Name length */
588 	char	name[];			/* File name, up to EXT2_NAME_LEN */
589 };
590 
591 /*
592  * The new version of the directory entry.  Since EXT2 structures are
593  * stored in intel byte order, and the name_len field could never be
594  * bigger than 255 chars, it's safe to reclaim the extra byte for the
595  * file_type field.
596  */
597 struct ext2_dir_entry_2 {
598 	__le32	inode;			/* Inode number */
599 	__le16	rec_len;		/* Directory entry length */
600 	__u8	name_len;		/* Name length */
601 	__u8	file_type;
602 	char	name[];			/* File name, up to EXT2_NAME_LEN */
603 };
604 
605 /*
606  * EXT2_DIR_PAD defines the directory entries boundaries
607  *
608  * NOTE: It must be a multiple of 4
609  */
610 #define EXT2_DIR_PAD		 	4
611 #define EXT2_DIR_ROUND 			(EXT2_DIR_PAD - 1)
612 #define EXT2_DIR_REC_LEN(name_len)	(((name_len) + 8 + EXT2_DIR_ROUND) & \
613 					 ~EXT2_DIR_ROUND)
614 #define EXT2_MAX_REC_LEN		((1<<16)-1)
615 
616 static inline void verify_offsets(void)
617 {
618 #define A(x,y) BUILD_BUG_ON(x != offsetof(struct ext2_super_block, y));
619 	A(EXT2_SB_MAGIC_OFFSET, s_magic);
620 	A(EXT2_SB_BLOCKS_OFFSET, s_blocks_count);
621 	A(EXT2_SB_BSIZE_OFFSET, s_log_block_size);
622 #undef A
623 }
624 
625 /*
626  * ext2 mount options
627  */
628 struct ext2_mount_options {
629 	unsigned long s_mount_opt;
630 	kuid_t s_resuid;
631 	kgid_t s_resgid;
632 };
633 
634 /*
635  * second extended file system inode data in memory
636  */
637 struct ext2_inode_info {
638 	__le32	i_data[15];
639 	__u32	i_flags;
640 	__u32	i_faddr;
641 	__u8	i_frag_no;
642 	__u8	i_frag_size;
643 	__u16	i_state;
644 	__u32	i_file_acl;
645 	__u32	i_dir_acl;
646 	__u32	i_dtime;
647 
648 	/*
649 	 * i_block_group is the number of the block group which contains
650 	 * this file's inode.  Constant across the lifetime of the inode,
651 	 * it is used for making block allocation decisions - we try to
652 	 * place a file's data blocks near its inode block, and new inodes
653 	 * near to their parent directory's inode.
654 	 */
655 	__u32	i_block_group;
656 
657 	/* block reservation info */
658 	struct ext2_block_alloc_info *i_block_alloc_info;
659 
660 	__u32	i_dir_start_lookup;
661 #ifdef CONFIG_EXT2_FS_XATTR
662 	/*
663 	 * Extended attributes can be read independently of the main file
664 	 * data. Taking i_mutex even when reading would cause contention
665 	 * between readers of EAs and writers of regular file data, so
666 	 * instead we synchronize on xattr_sem when reading or changing
667 	 * EAs.
668 	 */
669 	struct rw_semaphore xattr_sem;
670 #endif
671 	rwlock_t i_meta_lock;
672 #ifdef CONFIG_FS_DAX
673 	struct rw_semaphore dax_sem;
674 #endif
675 
676 	/*
677 	 * truncate_mutex is for serialising ext2_truncate() against
678 	 * ext2_getblock().  It also protects the internals of the inode's
679 	 * reservation data structures: ext2_reserve_window and
680 	 * ext2_reserve_window_node.
681 	 */
682 	struct mutex truncate_mutex;
683 	struct inode	vfs_inode;
684 	struct list_head i_orphan;	/* unlinked but open inodes */
685 #ifdef CONFIG_QUOTA
686 	struct dquot *i_dquot[MAXQUOTAS];
687 #endif
688 };
689 
690 #ifdef CONFIG_FS_DAX
691 #define dax_sem_down_write(ext2_inode)	down_write(&(ext2_inode)->dax_sem)
692 #define dax_sem_up_write(ext2_inode)	up_write(&(ext2_inode)->dax_sem)
693 #else
694 #define dax_sem_down_write(ext2_inode)
695 #define dax_sem_up_write(ext2_inode)
696 #endif
697 
698 /*
699  * Inode dynamic state flags
700  */
701 #define EXT2_STATE_NEW			0x00000001 /* inode is newly created */
702 
703 
704 /*
705  * Function prototypes
706  */
707 
708 /*
709  * Ok, these declarations are also in <linux/kernel.h> but none of the
710  * ext2 source programs needs to include it so they are duplicated here.
711  */
712 
713 static inline struct ext2_inode_info *EXT2_I(struct inode *inode)
714 {
715 	return container_of(inode, struct ext2_inode_info, vfs_inode);
716 }
717 
718 /* balloc.c */
719 extern int ext2_bg_has_super(struct super_block *sb, int group);
720 extern unsigned long ext2_bg_num_gdb(struct super_block *sb, int group);
721 extern ext2_fsblk_t ext2_new_block(struct inode *, unsigned long, int *);
722 extern ext2_fsblk_t ext2_new_blocks(struct inode *, unsigned long,
723 				unsigned long *, int *);
724 extern int ext2_data_block_valid(struct ext2_sb_info *sbi, ext2_fsblk_t start_blk,
725 				 unsigned int count);
726 extern void ext2_free_blocks (struct inode *, unsigned long,
727 			      unsigned long);
728 extern unsigned long ext2_count_free_blocks (struct super_block *);
729 extern unsigned long ext2_count_dirs (struct super_block *);
730 extern struct ext2_group_desc * ext2_get_group_desc(struct super_block * sb,
731 						    unsigned int block_group,
732 						    struct buffer_head ** bh);
733 extern void ext2_discard_reservation (struct inode *);
734 extern int ext2_should_retry_alloc(struct super_block *sb, int *retries);
735 extern void ext2_init_block_alloc_info(struct inode *);
736 extern void ext2_rsv_window_add(struct super_block *sb, struct ext2_reserve_window_node *rsv);
737 
738 /* dir.c */
739 extern int ext2_add_link (struct dentry *, struct inode *);
740 extern int ext2_inode_by_name(struct inode *dir,
741 			      const struct qstr *child, ino_t *ino);
742 extern int ext2_make_empty(struct inode *, struct inode *);
743 extern struct ext2_dir_entry_2 * ext2_find_entry (struct inode *,const struct qstr *, struct page **);
744 extern int ext2_delete_entry (struct ext2_dir_entry_2 *, struct page *);
745 extern int ext2_empty_dir (struct inode *);
746 extern struct ext2_dir_entry_2 * ext2_dotdot (struct inode *, struct page **);
747 extern void ext2_set_link(struct inode *, struct ext2_dir_entry_2 *, struct page *, struct inode *, int);
748 
749 /* ialloc.c */
750 extern struct inode * ext2_new_inode (struct inode *, umode_t, const struct qstr *);
751 extern void ext2_free_inode (struct inode *);
752 extern unsigned long ext2_count_free_inodes (struct super_block *);
753 extern unsigned long ext2_count_free (struct buffer_head *, unsigned);
754 
755 /* inode.c */
756 extern struct inode *ext2_iget (struct super_block *, unsigned long);
757 extern int ext2_write_inode (struct inode *, struct writeback_control *);
758 extern void ext2_evict_inode(struct inode *);
759 extern int ext2_get_block(struct inode *, sector_t, struct buffer_head *, int);
760 extern int ext2_setattr (struct dentry *, struct iattr *);
761 extern int ext2_getattr (const struct path *, struct kstat *, u32, unsigned int);
762 extern void ext2_set_inode_flags(struct inode *inode);
763 extern int ext2_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
764 		       u64 start, u64 len);
765 
766 /* ioctl.c */
767 extern long ext2_ioctl(struct file *, unsigned int, unsigned long);
768 extern long ext2_compat_ioctl(struct file *, unsigned int, unsigned long);
769 
770 /* namei.c */
771 struct dentry *ext2_get_parent(struct dentry *child);
772 
773 /* super.c */
774 extern __printf(3, 4)
775 void ext2_error(struct super_block *, const char *, const char *, ...);
776 extern __printf(3, 4)
777 void ext2_msg(struct super_block *, const char *, const char *, ...);
778 extern void ext2_update_dynamic_rev (struct super_block *sb);
779 extern void ext2_sync_super(struct super_block *sb, struct ext2_super_block *es,
780 			    int wait);
781 
782 /*
783  * Inodes and files operations
784  */
785 
786 /* dir.c */
787 extern const struct file_operations ext2_dir_operations;
788 
789 /* file.c */
790 extern int ext2_fsync(struct file *file, loff_t start, loff_t end,
791 		      int datasync);
792 extern const struct inode_operations ext2_file_inode_operations;
793 extern const struct file_operations ext2_file_operations;
794 
795 /* inode.c */
796 extern void ext2_set_file_ops(struct inode *inode);
797 extern const struct address_space_operations ext2_aops;
798 extern const struct address_space_operations ext2_nobh_aops;
799 extern const struct iomap_ops ext2_iomap_ops;
800 
801 /* namei.c */
802 extern const struct inode_operations ext2_dir_inode_operations;
803 extern const struct inode_operations ext2_special_inode_operations;
804 
805 /* symlink.c */
806 extern const struct inode_operations ext2_fast_symlink_inode_operations;
807 extern const struct inode_operations ext2_symlink_inode_operations;
808 
809 static inline ext2_fsblk_t
810 ext2_group_first_block_no(struct super_block *sb, unsigned long group_no)
811 {
812 	return group_no * (ext2_fsblk_t)EXT2_BLOCKS_PER_GROUP(sb) +
813 		le32_to_cpu(EXT2_SB(sb)->s_es->s_first_data_block);
814 }
815 
816 static inline ext2_fsblk_t
817 ext2_group_last_block_no(struct super_block *sb, unsigned long group_no)
818 {
819 	struct ext2_sb_info *sbi = EXT2_SB(sb);
820 
821 	if (group_no == sbi->s_groups_count - 1)
822 		return le32_to_cpu(sbi->s_es->s_blocks_count) - 1;
823 	else
824 		return ext2_group_first_block_no(sb, group_no) +
825 			EXT2_BLOCKS_PER_GROUP(sb) - 1;
826 }
827 
828 #define ext2_set_bit	__test_and_set_bit_le
829 #define ext2_clear_bit	__test_and_clear_bit_le
830 #define ext2_test_bit	test_bit_le
831 #define ext2_find_first_zero_bit	find_first_zero_bit_le
832 #define ext2_find_next_zero_bit		find_next_zero_bit_le
833