xref: /openbmc/linux/fs/ext2/ext2.h (revision 0edbfea5)
1 /*
2  * Copyright (C) 1992, 1993, 1994, 1995
3  * Remy Card (card@masi.ibp.fr)
4  * Laboratoire MASI - Institut Blaise Pascal
5  * Universite Pierre et Marie Curie (Paris VI)
6  *
7  *  from
8  *
9  *  linux/include/linux/minix_fs.h
10  *
11  *  Copyright (C) 1991, 1992  Linus Torvalds
12  */
13 #include <linux/fs.h>
14 #include <linux/ext2_fs.h>
15 #include <linux/blockgroup_lock.h>
16 #include <linux/percpu_counter.h>
17 #include <linux/rbtree.h>
18 
19 /* XXX Here for now... not interested in restructing headers JUST now */
20 
21 /* data type for block offset of block group */
22 typedef int ext2_grpblk_t;
23 
24 /* data type for filesystem-wide blocks number */
25 typedef unsigned long ext2_fsblk_t;
26 
27 #define E2FSBLK "%lu"
28 
29 struct ext2_reserve_window {
30 	ext2_fsblk_t		_rsv_start;	/* First byte reserved */
31 	ext2_fsblk_t		_rsv_end;	/* Last byte reserved or 0 */
32 };
33 
34 struct ext2_reserve_window_node {
35 	struct rb_node	 	rsv_node;
36 	__u32			rsv_goal_size;
37 	__u32			rsv_alloc_hit;
38 	struct ext2_reserve_window	rsv_window;
39 };
40 
41 struct ext2_block_alloc_info {
42 	/* information about reservation window */
43 	struct ext2_reserve_window_node	rsv_window_node;
44 	/*
45 	 * was i_next_alloc_block in ext2_inode_info
46 	 * is the logical (file-relative) number of the
47 	 * most-recently-allocated block in this file.
48 	 * We use this for detecting linearly ascending allocation requests.
49 	 */
50 	__u32			last_alloc_logical_block;
51 	/*
52 	 * Was i_next_alloc_goal in ext2_inode_info
53 	 * is the *physical* companion to i_next_alloc_block.
54 	 * it the the physical block number of the block which was most-recentl
55 	 * allocated to this file.  This give us the goal (target) for the next
56 	 * allocation when we detect linearly ascending requests.
57 	 */
58 	ext2_fsblk_t		last_alloc_physical_block;
59 };
60 
61 #define rsv_start rsv_window._rsv_start
62 #define rsv_end rsv_window._rsv_end
63 
64 struct mb_cache;
65 
66 /*
67  * second extended-fs super-block data in memory
68  */
69 struct ext2_sb_info {
70 	unsigned long s_frag_size;	/* Size of a fragment in bytes */
71 	unsigned long s_frags_per_block;/* Number of fragments per block */
72 	unsigned long s_inodes_per_block;/* Number of inodes per block */
73 	unsigned long s_frags_per_group;/* Number of fragments in a group */
74 	unsigned long s_blocks_per_group;/* Number of blocks in a group */
75 	unsigned long s_inodes_per_group;/* Number of inodes in a group */
76 	unsigned long s_itb_per_group;	/* Number of inode table blocks per group */
77 	unsigned long s_gdb_count;	/* Number of group descriptor blocks */
78 	unsigned long s_desc_per_block;	/* Number of group descriptors per block */
79 	unsigned long s_groups_count;	/* Number of groups in the fs */
80 	unsigned long s_overhead_last;  /* Last calculated overhead */
81 	unsigned long s_blocks_last;    /* Last seen block count */
82 	struct buffer_head * s_sbh;	/* Buffer containing the super block */
83 	struct ext2_super_block * s_es;	/* Pointer to the super block in the buffer */
84 	struct buffer_head ** s_group_desc;
85 	unsigned long  s_mount_opt;
86 	unsigned long s_sb_block;
87 	kuid_t s_resuid;
88 	kgid_t s_resgid;
89 	unsigned short s_mount_state;
90 	unsigned short s_pad;
91 	int s_addr_per_block_bits;
92 	int s_desc_per_block_bits;
93 	int s_inode_size;
94 	int s_first_ino;
95 	spinlock_t s_next_gen_lock;
96 	u32 s_next_generation;
97 	unsigned long s_dir_count;
98 	u8 *s_debts;
99 	struct percpu_counter s_freeblocks_counter;
100 	struct percpu_counter s_freeinodes_counter;
101 	struct percpu_counter s_dirs_counter;
102 	struct blockgroup_lock *s_blockgroup_lock;
103 	/* root of the per fs reservation window tree */
104 	spinlock_t s_rsv_window_lock;
105 	struct rb_root s_rsv_window_root;
106 	struct ext2_reserve_window_node s_rsv_window_head;
107 	/*
108 	 * s_lock protects against concurrent modifications of s_mount_state,
109 	 * s_blocks_last, s_overhead_last and the content of superblock's
110 	 * buffer pointed to by sbi->s_es.
111 	 *
112 	 * Note: It is used in ext2_show_options() to provide a consistent view
113 	 * of the mount options.
114 	 */
115 	spinlock_t s_lock;
116 	struct mb_cache *s_mb_cache;
117 };
118 
119 static inline spinlock_t *
120 sb_bgl_lock(struct ext2_sb_info *sbi, unsigned int block_group)
121 {
122 	return bgl_lock_ptr(sbi->s_blockgroup_lock, block_group);
123 }
124 
125 /*
126  * Define EXT2FS_DEBUG to produce debug messages
127  */
128 #undef EXT2FS_DEBUG
129 
130 /*
131  * Define EXT2_RESERVATION to reserve data blocks for expanding files
132  */
133 #define EXT2_DEFAULT_RESERVE_BLOCKS     8
134 /*max window size: 1024(direct blocks) + 3([t,d]indirect blocks) */
135 #define EXT2_MAX_RESERVE_BLOCKS         1027
136 #define EXT2_RESERVE_WINDOW_NOT_ALLOCATED 0
137 /*
138  * The second extended file system version
139  */
140 #define EXT2FS_DATE		"95/08/09"
141 #define EXT2FS_VERSION		"0.5b"
142 
143 /*
144  * Debug code
145  */
146 #ifdef EXT2FS_DEBUG
147 #	define ext2_debug(f, a...)	{ \
148 					printk ("EXT2-fs DEBUG (%s, %d): %s:", \
149 						__FILE__, __LINE__, __func__); \
150 				  	printk (f, ## a); \
151 					}
152 #else
153 #	define ext2_debug(f, a...)	/**/
154 #endif
155 
156 /*
157  * Special inode numbers
158  */
159 #define	EXT2_BAD_INO		 1	/* Bad blocks inode */
160 #define EXT2_ROOT_INO		 2	/* Root inode */
161 #define EXT2_BOOT_LOADER_INO	 5	/* Boot loader inode */
162 #define EXT2_UNDEL_DIR_INO	 6	/* Undelete directory inode */
163 
164 /* First non-reserved inode for old ext2 filesystems */
165 #define EXT2_GOOD_OLD_FIRST_INO	11
166 
167 static inline struct ext2_sb_info *EXT2_SB(struct super_block *sb)
168 {
169 	return sb->s_fs_info;
170 }
171 
172 /*
173  * Macro-instructions used to manage several block sizes
174  */
175 #define EXT2_MIN_BLOCK_SIZE		1024
176 #define	EXT2_MAX_BLOCK_SIZE		4096
177 #define EXT2_MIN_BLOCK_LOG_SIZE		  10
178 #define EXT2_BLOCK_SIZE(s)		((s)->s_blocksize)
179 #define	EXT2_ADDR_PER_BLOCK(s)		(EXT2_BLOCK_SIZE(s) / sizeof (__u32))
180 #define EXT2_BLOCK_SIZE_BITS(s)		((s)->s_blocksize_bits)
181 #define	EXT2_ADDR_PER_BLOCK_BITS(s)	(EXT2_SB(s)->s_addr_per_block_bits)
182 #define EXT2_INODE_SIZE(s)		(EXT2_SB(s)->s_inode_size)
183 #define EXT2_FIRST_INO(s)		(EXT2_SB(s)->s_first_ino)
184 
185 /*
186  * Macro-instructions used to manage fragments
187  */
188 #define EXT2_MIN_FRAG_SIZE		1024
189 #define	EXT2_MAX_FRAG_SIZE		4096
190 #define EXT2_MIN_FRAG_LOG_SIZE		  10
191 #define EXT2_FRAG_SIZE(s)		(EXT2_SB(s)->s_frag_size)
192 #define EXT2_FRAGS_PER_BLOCK(s)		(EXT2_SB(s)->s_frags_per_block)
193 
194 /*
195  * Structure of a blocks group descriptor
196  */
197 struct ext2_group_desc
198 {
199 	__le32	bg_block_bitmap;		/* Blocks bitmap block */
200 	__le32	bg_inode_bitmap;		/* Inodes bitmap block */
201 	__le32	bg_inode_table;		/* Inodes table block */
202 	__le16	bg_free_blocks_count;	/* Free blocks count */
203 	__le16	bg_free_inodes_count;	/* Free inodes count */
204 	__le16	bg_used_dirs_count;	/* Directories count */
205 	__le16	bg_pad;
206 	__le32	bg_reserved[3];
207 };
208 
209 /*
210  * Macro-instructions used to manage group descriptors
211  */
212 #define EXT2_BLOCKS_PER_GROUP(s)	(EXT2_SB(s)->s_blocks_per_group)
213 #define EXT2_DESC_PER_BLOCK(s)		(EXT2_SB(s)->s_desc_per_block)
214 #define EXT2_INODES_PER_GROUP(s)	(EXT2_SB(s)->s_inodes_per_group)
215 #define EXT2_DESC_PER_BLOCK_BITS(s)	(EXT2_SB(s)->s_desc_per_block_bits)
216 
217 /*
218  * Constants relative to the data blocks
219  */
220 #define	EXT2_NDIR_BLOCKS		12
221 #define	EXT2_IND_BLOCK			EXT2_NDIR_BLOCKS
222 #define	EXT2_DIND_BLOCK			(EXT2_IND_BLOCK + 1)
223 #define	EXT2_TIND_BLOCK			(EXT2_DIND_BLOCK + 1)
224 #define	EXT2_N_BLOCKS			(EXT2_TIND_BLOCK + 1)
225 
226 /*
227  * Inode flags (GETFLAGS/SETFLAGS)
228  */
229 #define	EXT2_SECRM_FL			FS_SECRM_FL	/* Secure deletion */
230 #define	EXT2_UNRM_FL			FS_UNRM_FL	/* Undelete */
231 #define	EXT2_COMPR_FL			FS_COMPR_FL	/* Compress file */
232 #define EXT2_SYNC_FL			FS_SYNC_FL	/* Synchronous updates */
233 #define EXT2_IMMUTABLE_FL		FS_IMMUTABLE_FL	/* Immutable file */
234 #define EXT2_APPEND_FL			FS_APPEND_FL	/* writes to file may only append */
235 #define EXT2_NODUMP_FL			FS_NODUMP_FL	/* do not dump file */
236 #define EXT2_NOATIME_FL			FS_NOATIME_FL	/* do not update atime */
237 /* Reserved for compression usage... */
238 #define EXT2_DIRTY_FL			FS_DIRTY_FL
239 #define EXT2_COMPRBLK_FL		FS_COMPRBLK_FL	/* One or more compressed clusters */
240 #define EXT2_NOCOMP_FL			FS_NOCOMP_FL	/* Don't compress */
241 #define EXT2_ECOMPR_FL			FS_ECOMPR_FL	/* Compression error */
242 /* End compression flags --- maybe not all used */
243 #define EXT2_BTREE_FL			FS_BTREE_FL	/* btree format dir */
244 #define EXT2_INDEX_FL			FS_INDEX_FL	/* hash-indexed directory */
245 #define EXT2_IMAGIC_FL			FS_IMAGIC_FL	/* AFS directory */
246 #define EXT2_JOURNAL_DATA_FL		FS_JOURNAL_DATA_FL /* Reserved for ext3 */
247 #define EXT2_NOTAIL_FL			FS_NOTAIL_FL	/* file tail should not be merged */
248 #define EXT2_DIRSYNC_FL			FS_DIRSYNC_FL	/* dirsync behaviour (directories only) */
249 #define EXT2_TOPDIR_FL			FS_TOPDIR_FL	/* Top of directory hierarchies*/
250 #define EXT2_RESERVED_FL		FS_RESERVED_FL	/* reserved for ext2 lib */
251 
252 #define EXT2_FL_USER_VISIBLE		FS_FL_USER_VISIBLE	/* User visible flags */
253 #define EXT2_FL_USER_MODIFIABLE		FS_FL_USER_MODIFIABLE	/* User modifiable flags */
254 
255 /* Flags that should be inherited by new inodes from their parent. */
256 #define EXT2_FL_INHERITED (EXT2_SECRM_FL | EXT2_UNRM_FL | EXT2_COMPR_FL |\
257 			   EXT2_SYNC_FL | EXT2_NODUMP_FL |\
258 			   EXT2_NOATIME_FL | EXT2_COMPRBLK_FL |\
259 			   EXT2_NOCOMP_FL | EXT2_JOURNAL_DATA_FL |\
260 			   EXT2_NOTAIL_FL | EXT2_DIRSYNC_FL)
261 
262 /* Flags that are appropriate for regular files (all but dir-specific ones). */
263 #define EXT2_REG_FLMASK (~(EXT2_DIRSYNC_FL | EXT2_TOPDIR_FL))
264 
265 /* Flags that are appropriate for non-directories/regular files. */
266 #define EXT2_OTHER_FLMASK (EXT2_NODUMP_FL | EXT2_NOATIME_FL)
267 
268 /* Mask out flags that are inappropriate for the given type of inode. */
269 static inline __u32 ext2_mask_flags(umode_t mode, __u32 flags)
270 {
271 	if (S_ISDIR(mode))
272 		return flags;
273 	else if (S_ISREG(mode))
274 		return flags & EXT2_REG_FLMASK;
275 	else
276 		return flags & EXT2_OTHER_FLMASK;
277 }
278 
279 /*
280  * ioctl commands
281  */
282 #define	EXT2_IOC_GETFLAGS		FS_IOC_GETFLAGS
283 #define	EXT2_IOC_SETFLAGS		FS_IOC_SETFLAGS
284 #define	EXT2_IOC_GETVERSION		FS_IOC_GETVERSION
285 #define	EXT2_IOC_SETVERSION		FS_IOC_SETVERSION
286 #define	EXT2_IOC_GETRSVSZ		_IOR('f', 5, long)
287 #define	EXT2_IOC_SETRSVSZ		_IOW('f', 6, long)
288 
289 /*
290  * ioctl commands in 32 bit emulation
291  */
292 #define EXT2_IOC32_GETFLAGS		FS_IOC32_GETFLAGS
293 #define EXT2_IOC32_SETFLAGS		FS_IOC32_SETFLAGS
294 #define EXT2_IOC32_GETVERSION		FS_IOC32_GETVERSION
295 #define EXT2_IOC32_SETVERSION		FS_IOC32_SETVERSION
296 
297 /*
298  * Structure of an inode on the disk
299  */
300 struct ext2_inode {
301 	__le16	i_mode;		/* File mode */
302 	__le16	i_uid;		/* Low 16 bits of Owner Uid */
303 	__le32	i_size;		/* Size in bytes */
304 	__le32	i_atime;	/* Access time */
305 	__le32	i_ctime;	/* Creation time */
306 	__le32	i_mtime;	/* Modification time */
307 	__le32	i_dtime;	/* Deletion Time */
308 	__le16	i_gid;		/* Low 16 bits of Group Id */
309 	__le16	i_links_count;	/* Links count */
310 	__le32	i_blocks;	/* Blocks count */
311 	__le32	i_flags;	/* File flags */
312 	union {
313 		struct {
314 			__le32  l_i_reserved1;
315 		} linux1;
316 		struct {
317 			__le32  h_i_translator;
318 		} hurd1;
319 		struct {
320 			__le32  m_i_reserved1;
321 		} masix1;
322 	} osd1;				/* OS dependent 1 */
323 	__le32	i_block[EXT2_N_BLOCKS];/* Pointers to blocks */
324 	__le32	i_generation;	/* File version (for NFS) */
325 	__le32	i_file_acl;	/* File ACL */
326 	__le32	i_dir_acl;	/* Directory ACL */
327 	__le32	i_faddr;	/* Fragment address */
328 	union {
329 		struct {
330 			__u8	l_i_frag;	/* Fragment number */
331 			__u8	l_i_fsize;	/* Fragment size */
332 			__u16	i_pad1;
333 			__le16	l_i_uid_high;	/* these 2 fields    */
334 			__le16	l_i_gid_high;	/* were reserved2[0] */
335 			__u32	l_i_reserved2;
336 		} linux2;
337 		struct {
338 			__u8	h_i_frag;	/* Fragment number */
339 			__u8	h_i_fsize;	/* Fragment size */
340 			__le16	h_i_mode_high;
341 			__le16	h_i_uid_high;
342 			__le16	h_i_gid_high;
343 			__le32	h_i_author;
344 		} hurd2;
345 		struct {
346 			__u8	m_i_frag;	/* Fragment number */
347 			__u8	m_i_fsize;	/* Fragment size */
348 			__u16	m_pad1;
349 			__u32	m_i_reserved2[2];
350 		} masix2;
351 	} osd2;				/* OS dependent 2 */
352 };
353 
354 #define i_size_high	i_dir_acl
355 
356 #define i_reserved1	osd1.linux1.l_i_reserved1
357 #define i_frag		osd2.linux2.l_i_frag
358 #define i_fsize		osd2.linux2.l_i_fsize
359 #define i_uid_low	i_uid
360 #define i_gid_low	i_gid
361 #define i_uid_high	osd2.linux2.l_i_uid_high
362 #define i_gid_high	osd2.linux2.l_i_gid_high
363 #define i_reserved2	osd2.linux2.l_i_reserved2
364 
365 /*
366  * File system states
367  */
368 #define	EXT2_VALID_FS			0x0001	/* Unmounted cleanly */
369 #define	EXT2_ERROR_FS			0x0002	/* Errors detected */
370 
371 /*
372  * Mount flags
373  */
374 #define EXT2_MOUNT_CHECK		0x000001  /* Do mount-time checks */
375 #define EXT2_MOUNT_OLDALLOC		0x000002  /* Don't use the new Orlov allocator */
376 #define EXT2_MOUNT_GRPID		0x000004  /* Create files with directory's group */
377 #define EXT2_MOUNT_DEBUG		0x000008  /* Some debugging messages */
378 #define EXT2_MOUNT_ERRORS_CONT		0x000010  /* Continue on errors */
379 #define EXT2_MOUNT_ERRORS_RO		0x000020  /* Remount fs ro on errors */
380 #define EXT2_MOUNT_ERRORS_PANIC		0x000040  /* Panic on errors */
381 #define EXT2_MOUNT_MINIX_DF		0x000080  /* Mimics the Minix statfs */
382 #define EXT2_MOUNT_NOBH			0x000100  /* No buffer_heads */
383 #define EXT2_MOUNT_NO_UID32		0x000200  /* Disable 32-bit UIDs */
384 #define EXT2_MOUNT_XATTR_USER		0x004000  /* Extended user attributes */
385 #define EXT2_MOUNT_POSIX_ACL		0x008000  /* POSIX Access Control Lists */
386 #define EXT2_MOUNT_XIP			0x010000  /* Obsolete, use DAX */
387 #define EXT2_MOUNT_USRQUOTA		0x020000  /* user quota */
388 #define EXT2_MOUNT_GRPQUOTA		0x040000  /* group quota */
389 #define EXT2_MOUNT_RESERVATION		0x080000  /* Preallocation */
390 #ifdef CONFIG_FS_DAX
391 #define EXT2_MOUNT_DAX			0x100000  /* Direct Access */
392 #else
393 #define EXT2_MOUNT_DAX			0
394 #endif
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 directory file types.  Only the low 3 bits are used.  The
609  * other bits are reserved for now.
610  */
611 enum {
612 	EXT2_FT_UNKNOWN		= 0,
613 	EXT2_FT_REG_FILE	= 1,
614 	EXT2_FT_DIR		= 2,
615 	EXT2_FT_CHRDEV		= 3,
616 	EXT2_FT_BLKDEV		= 4,
617 	EXT2_FT_FIFO		= 5,
618 	EXT2_FT_SOCK		= 6,
619 	EXT2_FT_SYMLINK		= 7,
620 	EXT2_FT_MAX
621 };
622 
623 /*
624  * EXT2_DIR_PAD defines the directory entries boundaries
625  *
626  * NOTE: It must be a multiple of 4
627  */
628 #define EXT2_DIR_PAD		 	4
629 #define EXT2_DIR_ROUND 			(EXT2_DIR_PAD - 1)
630 #define EXT2_DIR_REC_LEN(name_len)	(((name_len) + 8 + EXT2_DIR_ROUND) & \
631 					 ~EXT2_DIR_ROUND)
632 #define EXT2_MAX_REC_LEN		((1<<16)-1)
633 
634 static inline void verify_offsets(void)
635 {
636 #define A(x,y) BUILD_BUG_ON(x != offsetof(struct ext2_super_block, y));
637 	A(EXT2_SB_MAGIC_OFFSET, s_magic);
638 	A(EXT2_SB_BLOCKS_OFFSET, s_blocks_count);
639 	A(EXT2_SB_BSIZE_OFFSET, s_log_block_size);
640 #undef A
641 }
642 
643 /*
644  * ext2 mount options
645  */
646 struct ext2_mount_options {
647 	unsigned long s_mount_opt;
648 	kuid_t s_resuid;
649 	kgid_t s_resgid;
650 };
651 
652 /*
653  * second extended file system inode data in memory
654  */
655 struct ext2_inode_info {
656 	__le32	i_data[15];
657 	__u32	i_flags;
658 	__u32	i_faddr;
659 	__u8	i_frag_no;
660 	__u8	i_frag_size;
661 	__u16	i_state;
662 	__u32	i_file_acl;
663 	__u32	i_dir_acl;
664 	__u32	i_dtime;
665 
666 	/*
667 	 * i_block_group is the number of the block group which contains
668 	 * this file's inode.  Constant across the lifetime of the inode,
669 	 * it is used for making block allocation decisions - we try to
670 	 * place a file's data blocks near its inode block, and new inodes
671 	 * near to their parent directory's inode.
672 	 */
673 	__u32	i_block_group;
674 
675 	/* block reservation info */
676 	struct ext2_block_alloc_info *i_block_alloc_info;
677 
678 	__u32	i_dir_start_lookup;
679 #ifdef CONFIG_EXT2_FS_XATTR
680 	/*
681 	 * Extended attributes can be read independently of the main file
682 	 * data. Taking i_mutex even when reading would cause contention
683 	 * between readers of EAs and writers of regular file data, so
684 	 * instead we synchronize on xattr_sem when reading or changing
685 	 * EAs.
686 	 */
687 	struct rw_semaphore xattr_sem;
688 #endif
689 	rwlock_t i_meta_lock;
690 #ifdef CONFIG_FS_DAX
691 	struct rw_semaphore dax_sem;
692 #endif
693 
694 	/*
695 	 * truncate_mutex is for serialising ext2_truncate() against
696 	 * ext2_getblock().  It also protects the internals of the inode's
697 	 * reservation data structures: ext2_reserve_window and
698 	 * ext2_reserve_window_node.
699 	 */
700 	struct mutex truncate_mutex;
701 	struct inode	vfs_inode;
702 	struct list_head i_orphan;	/* unlinked but open inodes */
703 #ifdef CONFIG_QUOTA
704 	struct dquot *i_dquot[MAXQUOTAS];
705 #endif
706 };
707 
708 #ifdef CONFIG_FS_DAX
709 #define dax_sem_down_write(ext2_inode)	down_write(&(ext2_inode)->dax_sem)
710 #define dax_sem_up_write(ext2_inode)	up_write(&(ext2_inode)->dax_sem)
711 #else
712 #define dax_sem_down_write(ext2_inode)
713 #define dax_sem_up_write(ext2_inode)
714 #endif
715 
716 /*
717  * Inode dynamic state flags
718  */
719 #define EXT2_STATE_NEW			0x00000001 /* inode is newly created */
720 
721 
722 /*
723  * Function prototypes
724  */
725 
726 /*
727  * Ok, these declarations are also in <linux/kernel.h> but none of the
728  * ext2 source programs needs to include it so they are duplicated here.
729  */
730 
731 static inline struct ext2_inode_info *EXT2_I(struct inode *inode)
732 {
733 	return container_of(inode, struct ext2_inode_info, vfs_inode);
734 }
735 
736 /* balloc.c */
737 extern int ext2_bg_has_super(struct super_block *sb, int group);
738 extern unsigned long ext2_bg_num_gdb(struct super_block *sb, int group);
739 extern ext2_fsblk_t ext2_new_block(struct inode *, unsigned long, int *);
740 extern ext2_fsblk_t ext2_new_blocks(struct inode *, unsigned long,
741 				unsigned long *, int *);
742 extern void ext2_free_blocks (struct inode *, unsigned long,
743 			      unsigned long);
744 extern unsigned long ext2_count_free_blocks (struct super_block *);
745 extern unsigned long ext2_count_dirs (struct super_block *);
746 extern void ext2_check_blocks_bitmap (struct super_block *);
747 extern struct ext2_group_desc * ext2_get_group_desc(struct super_block * sb,
748 						    unsigned int block_group,
749 						    struct buffer_head ** bh);
750 extern void ext2_discard_reservation (struct inode *);
751 extern int ext2_should_retry_alloc(struct super_block *sb, int *retries);
752 extern void ext2_init_block_alloc_info(struct inode *);
753 extern void ext2_rsv_window_add(struct super_block *sb, struct ext2_reserve_window_node *rsv);
754 
755 /* dir.c */
756 extern int ext2_add_link (struct dentry *, struct inode *);
757 extern ino_t ext2_inode_by_name(struct inode *, struct qstr *);
758 extern int ext2_make_empty(struct inode *, struct inode *);
759 extern struct ext2_dir_entry_2 * ext2_find_entry (struct inode *,struct qstr *, struct page **);
760 extern int ext2_delete_entry (struct ext2_dir_entry_2 *, struct page *);
761 extern int ext2_empty_dir (struct inode *);
762 extern struct ext2_dir_entry_2 * ext2_dotdot (struct inode *, struct page **);
763 extern void ext2_set_link(struct inode *, struct ext2_dir_entry_2 *, struct page *, struct inode *, int);
764 
765 /* ialloc.c */
766 extern struct inode * ext2_new_inode (struct inode *, umode_t, const struct qstr *);
767 extern void ext2_free_inode (struct inode *);
768 extern unsigned long ext2_count_free_inodes (struct super_block *);
769 extern void ext2_check_inodes_bitmap (struct super_block *);
770 extern unsigned long ext2_count_free (struct buffer_head *, unsigned);
771 
772 /* inode.c */
773 extern struct inode *ext2_iget (struct super_block *, unsigned long);
774 extern int ext2_write_inode (struct inode *, struct writeback_control *);
775 extern void ext2_evict_inode(struct inode *);
776 extern int ext2_get_block(struct inode *, sector_t, struct buffer_head *, int);
777 extern int ext2_setattr (struct dentry *, struct iattr *);
778 extern void ext2_set_inode_flags(struct inode *inode);
779 extern void ext2_get_inode_flags(struct ext2_inode_info *);
780 extern int ext2_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
781 		       u64 start, u64 len);
782 
783 /* ioctl.c */
784 extern long ext2_ioctl(struct file *, unsigned int, unsigned long);
785 extern long ext2_compat_ioctl(struct file *, unsigned int, unsigned long);
786 
787 /* namei.c */
788 struct dentry *ext2_get_parent(struct dentry *child);
789 
790 /* super.c */
791 extern __printf(3, 4)
792 void ext2_error(struct super_block *, const char *, const char *, ...);
793 extern __printf(3, 4)
794 void ext2_msg(struct super_block *, const char *, const char *, ...);
795 extern void ext2_update_dynamic_rev (struct super_block *sb);
796 extern void ext2_write_super (struct super_block *);
797 
798 /*
799  * Inodes and files operations
800  */
801 
802 /* dir.c */
803 extern const struct file_operations ext2_dir_operations;
804 
805 /* file.c */
806 extern int ext2_fsync(struct file *file, loff_t start, loff_t end,
807 		      int datasync);
808 extern const struct inode_operations ext2_file_inode_operations;
809 extern const struct file_operations ext2_file_operations;
810 
811 /* inode.c */
812 extern const struct address_space_operations ext2_aops;
813 extern const struct address_space_operations ext2_nobh_aops;
814 
815 /* namei.c */
816 extern const struct inode_operations ext2_dir_inode_operations;
817 extern const struct inode_operations ext2_special_inode_operations;
818 
819 /* symlink.c */
820 extern const struct inode_operations ext2_fast_symlink_inode_operations;
821 extern const struct inode_operations ext2_symlink_inode_operations;
822 
823 static inline ext2_fsblk_t
824 ext2_group_first_block_no(struct super_block *sb, unsigned long group_no)
825 {
826 	return group_no * (ext2_fsblk_t)EXT2_BLOCKS_PER_GROUP(sb) +
827 		le32_to_cpu(EXT2_SB(sb)->s_es->s_first_data_block);
828 }
829 
830 #define ext2_set_bit	__test_and_set_bit_le
831 #define ext2_clear_bit	__test_and_clear_bit_le
832 #define ext2_test_bit	test_bit_le
833 #define ext2_find_first_zero_bit	find_first_zero_bit_le
834 #define ext2_find_next_zero_bit		find_next_zero_bit_le
835