xref: /linux/fs/ext2/ext2.h (revision 827634added7f38b7d724cab1dccdb2b004c13c3)
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 /*
65  * second extended-fs super-block data in memory
66  */
67 struct ext2_sb_info {
68 	unsigned long s_frag_size;	/* Size of a fragment in bytes */
69 	unsigned long s_frags_per_block;/* Number of fragments per block */
70 	unsigned long s_inodes_per_block;/* Number of inodes per block */
71 	unsigned long s_frags_per_group;/* Number of fragments in a group */
72 	unsigned long s_blocks_per_group;/* Number of blocks in a group */
73 	unsigned long s_inodes_per_group;/* Number of inodes in a group */
74 	unsigned long s_itb_per_group;	/* Number of inode table blocks per group */
75 	unsigned long s_gdb_count;	/* Number of group descriptor blocks */
76 	unsigned long s_desc_per_block;	/* Number of group descriptors per block */
77 	unsigned long s_groups_count;	/* Number of groups in the fs */
78 	unsigned long s_overhead_last;  /* Last calculated overhead */
79 	unsigned long s_blocks_last;    /* Last seen block count */
80 	struct buffer_head * s_sbh;	/* Buffer containing the super block */
81 	struct ext2_super_block * s_es;	/* Pointer to the super block in the buffer */
82 	struct buffer_head ** s_group_desc;
83 	unsigned long  s_mount_opt;
84 	unsigned long s_sb_block;
85 	kuid_t s_resuid;
86 	kgid_t s_resgid;
87 	unsigned short s_mount_state;
88 	unsigned short s_pad;
89 	int s_addr_per_block_bits;
90 	int s_desc_per_block_bits;
91 	int s_inode_size;
92 	int s_first_ino;
93 	spinlock_t s_next_gen_lock;
94 	u32 s_next_generation;
95 	unsigned long s_dir_count;
96 	u8 *s_debts;
97 	struct percpu_counter s_freeblocks_counter;
98 	struct percpu_counter s_freeinodes_counter;
99 	struct percpu_counter s_dirs_counter;
100 	struct blockgroup_lock *s_blockgroup_lock;
101 	/* root of the per fs reservation window tree */
102 	spinlock_t s_rsv_window_lock;
103 	struct rb_root s_rsv_window_root;
104 	struct ext2_reserve_window_node s_rsv_window_head;
105 	/*
106 	 * s_lock protects against concurrent modifications of s_mount_state,
107 	 * s_blocks_last, s_overhead_last and the content of superblock's
108 	 * buffer pointed to by sbi->s_es.
109 	 *
110 	 * Note: It is used in ext2_show_options() to provide a consistent view
111 	 * of the mount options.
112 	 */
113 	spinlock_t s_lock;
114 };
115 
116 static inline spinlock_t *
117 sb_bgl_lock(struct ext2_sb_info *sbi, unsigned int block_group)
118 {
119 	return bgl_lock_ptr(sbi->s_blockgroup_lock, block_group);
120 }
121 
122 /*
123  * Define EXT2FS_DEBUG to produce debug messages
124  */
125 #undef EXT2FS_DEBUG
126 
127 /*
128  * Define EXT2_RESERVATION to reserve data blocks for expanding files
129  */
130 #define EXT2_DEFAULT_RESERVE_BLOCKS     8
131 /*max window size: 1024(direct blocks) + 3([t,d]indirect blocks) */
132 #define EXT2_MAX_RESERVE_BLOCKS         1027
133 #define EXT2_RESERVE_WINDOW_NOT_ALLOCATED 0
134 /*
135  * The second extended file system version
136  */
137 #define EXT2FS_DATE		"95/08/09"
138 #define EXT2FS_VERSION		"0.5b"
139 
140 /*
141  * Debug code
142  */
143 #ifdef EXT2FS_DEBUG
144 #	define ext2_debug(f, a...)	{ \
145 					printk ("EXT2-fs DEBUG (%s, %d): %s:", \
146 						__FILE__, __LINE__, __func__); \
147 				  	printk (f, ## a); \
148 					}
149 #else
150 #	define ext2_debug(f, a...)	/**/
151 #endif
152 
153 /*
154  * Special inode numbers
155  */
156 #define	EXT2_BAD_INO		 1	/* Bad blocks inode */
157 #define EXT2_ROOT_INO		 2	/* Root inode */
158 #define EXT2_BOOT_LOADER_INO	 5	/* Boot loader inode */
159 #define EXT2_UNDEL_DIR_INO	 6	/* Undelete directory inode */
160 
161 /* First non-reserved inode for old ext2 filesystems */
162 #define EXT2_GOOD_OLD_FIRST_INO	11
163 
164 static inline struct ext2_sb_info *EXT2_SB(struct super_block *sb)
165 {
166 	return sb->s_fs_info;
167 }
168 
169 /*
170  * Macro-instructions used to manage several block sizes
171  */
172 #define EXT2_MIN_BLOCK_SIZE		1024
173 #define	EXT2_MAX_BLOCK_SIZE		4096
174 #define EXT2_MIN_BLOCK_LOG_SIZE		  10
175 #define EXT2_BLOCK_SIZE(s)		((s)->s_blocksize)
176 #define	EXT2_ADDR_PER_BLOCK(s)		(EXT2_BLOCK_SIZE(s) / sizeof (__u32))
177 #define EXT2_BLOCK_SIZE_BITS(s)		((s)->s_blocksize_bits)
178 #define	EXT2_ADDR_PER_BLOCK_BITS(s)	(EXT2_SB(s)->s_addr_per_block_bits)
179 #define EXT2_INODE_SIZE(s)		(EXT2_SB(s)->s_inode_size)
180 #define EXT2_FIRST_INO(s)		(EXT2_SB(s)->s_first_ino)
181 
182 /*
183  * Macro-instructions used to manage fragments
184  */
185 #define EXT2_MIN_FRAG_SIZE		1024
186 #define	EXT2_MAX_FRAG_SIZE		4096
187 #define EXT2_MIN_FRAG_LOG_SIZE		  10
188 #define EXT2_FRAG_SIZE(s)		(EXT2_SB(s)->s_frag_size)
189 #define EXT2_FRAGS_PER_BLOCK(s)		(EXT2_SB(s)->s_frags_per_block)
190 
191 /*
192  * Structure of a blocks group descriptor
193  */
194 struct ext2_group_desc
195 {
196 	__le32	bg_block_bitmap;		/* Blocks bitmap block */
197 	__le32	bg_inode_bitmap;		/* Inodes bitmap block */
198 	__le32	bg_inode_table;		/* Inodes table block */
199 	__le16	bg_free_blocks_count;	/* Free blocks count */
200 	__le16	bg_free_inodes_count;	/* Free inodes count */
201 	__le16	bg_used_dirs_count;	/* Directories count */
202 	__le16	bg_pad;
203 	__le32	bg_reserved[3];
204 };
205 
206 /*
207  * Macro-instructions used to manage group descriptors
208  */
209 #define EXT2_BLOCKS_PER_GROUP(s)	(EXT2_SB(s)->s_blocks_per_group)
210 #define EXT2_DESC_PER_BLOCK(s)		(EXT2_SB(s)->s_desc_per_block)
211 #define EXT2_INODES_PER_GROUP(s)	(EXT2_SB(s)->s_inodes_per_group)
212 #define EXT2_DESC_PER_BLOCK_BITS(s)	(EXT2_SB(s)->s_desc_per_block_bits)
213 
214 /*
215  * Constants relative to the data blocks
216  */
217 #define	EXT2_NDIR_BLOCKS		12
218 #define	EXT2_IND_BLOCK			EXT2_NDIR_BLOCKS
219 #define	EXT2_DIND_BLOCK			(EXT2_IND_BLOCK + 1)
220 #define	EXT2_TIND_BLOCK			(EXT2_DIND_BLOCK + 1)
221 #define	EXT2_N_BLOCKS			(EXT2_TIND_BLOCK + 1)
222 
223 /*
224  * Inode flags (GETFLAGS/SETFLAGS)
225  */
226 #define	EXT2_SECRM_FL			FS_SECRM_FL	/* Secure deletion */
227 #define	EXT2_UNRM_FL			FS_UNRM_FL	/* Undelete */
228 #define	EXT2_COMPR_FL			FS_COMPR_FL	/* Compress file */
229 #define EXT2_SYNC_FL			FS_SYNC_FL	/* Synchronous updates */
230 #define EXT2_IMMUTABLE_FL		FS_IMMUTABLE_FL	/* Immutable file */
231 #define EXT2_APPEND_FL			FS_APPEND_FL	/* writes to file may only append */
232 #define EXT2_NODUMP_FL			FS_NODUMP_FL	/* do not dump file */
233 #define EXT2_NOATIME_FL			FS_NOATIME_FL	/* do not update atime */
234 /* Reserved for compression usage... */
235 #define EXT2_DIRTY_FL			FS_DIRTY_FL
236 #define EXT2_COMPRBLK_FL		FS_COMPRBLK_FL	/* One or more compressed clusters */
237 #define EXT2_NOCOMP_FL			FS_NOCOMP_FL	/* Don't compress */
238 #define EXT2_ECOMPR_FL			FS_ECOMPR_FL	/* Compression error */
239 /* End compression flags --- maybe not all used */
240 #define EXT2_BTREE_FL			FS_BTREE_FL	/* btree format dir */
241 #define EXT2_INDEX_FL			FS_INDEX_FL	/* hash-indexed directory */
242 #define EXT2_IMAGIC_FL			FS_IMAGIC_FL	/* AFS directory */
243 #define EXT2_JOURNAL_DATA_FL		FS_JOURNAL_DATA_FL /* Reserved for ext3 */
244 #define EXT2_NOTAIL_FL			FS_NOTAIL_FL	/* file tail should not be merged */
245 #define EXT2_DIRSYNC_FL			FS_DIRSYNC_FL	/* dirsync behaviour (directories only) */
246 #define EXT2_TOPDIR_FL			FS_TOPDIR_FL	/* Top of directory hierarchies*/
247 #define EXT2_RESERVED_FL		FS_RESERVED_FL	/* reserved for ext2 lib */
248 
249 #define EXT2_FL_USER_VISIBLE		FS_FL_USER_VISIBLE	/* User visible flags */
250 #define EXT2_FL_USER_MODIFIABLE		FS_FL_USER_MODIFIABLE	/* User modifiable flags */
251 
252 /* Flags that should be inherited by new inodes from their parent. */
253 #define EXT2_FL_INHERITED (EXT2_SECRM_FL | EXT2_UNRM_FL | EXT2_COMPR_FL |\
254 			   EXT2_SYNC_FL | EXT2_NODUMP_FL |\
255 			   EXT2_NOATIME_FL | EXT2_COMPRBLK_FL |\
256 			   EXT2_NOCOMP_FL | EXT2_JOURNAL_DATA_FL |\
257 			   EXT2_NOTAIL_FL | EXT2_DIRSYNC_FL)
258 
259 /* Flags that are appropriate for regular files (all but dir-specific ones). */
260 #define EXT2_REG_FLMASK (~(EXT2_DIRSYNC_FL | EXT2_TOPDIR_FL))
261 
262 /* Flags that are appropriate for non-directories/regular files. */
263 #define EXT2_OTHER_FLMASK (EXT2_NODUMP_FL | EXT2_NOATIME_FL)
264 
265 /* Mask out flags that are inappropriate for the given type of inode. */
266 static inline __u32 ext2_mask_flags(umode_t mode, __u32 flags)
267 {
268 	if (S_ISDIR(mode))
269 		return flags;
270 	else if (S_ISREG(mode))
271 		return flags & EXT2_REG_FLMASK;
272 	else
273 		return flags & EXT2_OTHER_FLMASK;
274 }
275 
276 /*
277  * ioctl commands
278  */
279 #define	EXT2_IOC_GETFLAGS		FS_IOC_GETFLAGS
280 #define	EXT2_IOC_SETFLAGS		FS_IOC_SETFLAGS
281 #define	EXT2_IOC_GETVERSION		FS_IOC_GETVERSION
282 #define	EXT2_IOC_SETVERSION		FS_IOC_SETVERSION
283 #define	EXT2_IOC_GETRSVSZ		_IOR('f', 5, long)
284 #define	EXT2_IOC_SETRSVSZ		_IOW('f', 6, long)
285 
286 /*
287  * ioctl commands in 32 bit emulation
288  */
289 #define EXT2_IOC32_GETFLAGS		FS_IOC32_GETFLAGS
290 #define EXT2_IOC32_SETFLAGS		FS_IOC32_SETFLAGS
291 #define EXT2_IOC32_GETVERSION		FS_IOC32_GETVERSION
292 #define EXT2_IOC32_SETVERSION		FS_IOC32_SETVERSION
293 
294 /*
295  * Structure of an inode on the disk
296  */
297 struct ext2_inode {
298 	__le16	i_mode;		/* File mode */
299 	__le16	i_uid;		/* Low 16 bits of Owner Uid */
300 	__le32	i_size;		/* Size in bytes */
301 	__le32	i_atime;	/* Access time */
302 	__le32	i_ctime;	/* Creation time */
303 	__le32	i_mtime;	/* Modification time */
304 	__le32	i_dtime;	/* Deletion Time */
305 	__le16	i_gid;		/* Low 16 bits of Group Id */
306 	__le16	i_links_count;	/* Links count */
307 	__le32	i_blocks;	/* Blocks count */
308 	__le32	i_flags;	/* File flags */
309 	union {
310 		struct {
311 			__le32  l_i_reserved1;
312 		} linux1;
313 		struct {
314 			__le32  h_i_translator;
315 		} hurd1;
316 		struct {
317 			__le32  m_i_reserved1;
318 		} masix1;
319 	} osd1;				/* OS dependent 1 */
320 	__le32	i_block[EXT2_N_BLOCKS];/* Pointers to blocks */
321 	__le32	i_generation;	/* File version (for NFS) */
322 	__le32	i_file_acl;	/* File ACL */
323 	__le32	i_dir_acl;	/* Directory ACL */
324 	__le32	i_faddr;	/* Fragment address */
325 	union {
326 		struct {
327 			__u8	l_i_frag;	/* Fragment number */
328 			__u8	l_i_fsize;	/* Fragment size */
329 			__u16	i_pad1;
330 			__le16	l_i_uid_high;	/* these 2 fields    */
331 			__le16	l_i_gid_high;	/* were reserved2[0] */
332 			__u32	l_i_reserved2;
333 		} linux2;
334 		struct {
335 			__u8	h_i_frag;	/* Fragment number */
336 			__u8	h_i_fsize;	/* Fragment size */
337 			__le16	h_i_mode_high;
338 			__le16	h_i_uid_high;
339 			__le16	h_i_gid_high;
340 			__le32	h_i_author;
341 		} hurd2;
342 		struct {
343 			__u8	m_i_frag;	/* Fragment number */
344 			__u8	m_i_fsize;	/* Fragment size */
345 			__u16	m_pad1;
346 			__u32	m_i_reserved2[2];
347 		} masix2;
348 	} osd2;				/* OS dependent 2 */
349 };
350 
351 #define i_size_high	i_dir_acl
352 
353 #define i_reserved1	osd1.linux1.l_i_reserved1
354 #define i_frag		osd2.linux2.l_i_frag
355 #define i_fsize		osd2.linux2.l_i_fsize
356 #define i_uid_low	i_uid
357 #define i_gid_low	i_gid
358 #define i_uid_high	osd2.linux2.l_i_uid_high
359 #define i_gid_high	osd2.linux2.l_i_gid_high
360 #define i_reserved2	osd2.linux2.l_i_reserved2
361 
362 /*
363  * File system states
364  */
365 #define	EXT2_VALID_FS			0x0001	/* Unmounted cleanly */
366 #define	EXT2_ERROR_FS			0x0002	/* Errors detected */
367 
368 /*
369  * Mount flags
370  */
371 #define EXT2_MOUNT_CHECK		0x000001  /* Do mount-time checks */
372 #define EXT2_MOUNT_OLDALLOC		0x000002  /* Don't use the new Orlov allocator */
373 #define EXT2_MOUNT_GRPID		0x000004  /* Create files with directory's group */
374 #define EXT2_MOUNT_DEBUG		0x000008  /* Some debugging messages */
375 #define EXT2_MOUNT_ERRORS_CONT		0x000010  /* Continue on errors */
376 #define EXT2_MOUNT_ERRORS_RO		0x000020  /* Remount fs ro on errors */
377 #define EXT2_MOUNT_ERRORS_PANIC		0x000040  /* Panic on errors */
378 #define EXT2_MOUNT_MINIX_DF		0x000080  /* Mimics the Minix statfs */
379 #define EXT2_MOUNT_NOBH			0x000100  /* No buffer_heads */
380 #define EXT2_MOUNT_NO_UID32		0x000200  /* Disable 32-bit UIDs */
381 #define EXT2_MOUNT_XATTR_USER		0x004000  /* Extended user attributes */
382 #define EXT2_MOUNT_POSIX_ACL		0x008000  /* POSIX Access Control Lists */
383 #define EXT2_MOUNT_XIP			0x010000  /* Obsolete, use DAX */
384 #define EXT2_MOUNT_USRQUOTA		0x020000  /* user quota */
385 #define EXT2_MOUNT_GRPQUOTA		0x040000  /* group quota */
386 #define EXT2_MOUNT_RESERVATION		0x080000  /* Preallocation */
387 #ifdef CONFIG_FS_DAX
388 #define EXT2_MOUNT_DAX			0x100000  /* Direct Access */
389 #else
390 #define EXT2_MOUNT_DAX			0
391 #endif
392 
393 
394 #define clear_opt(o, opt)		o &= ~EXT2_MOUNT_##opt
395 #define set_opt(o, opt)			o |= EXT2_MOUNT_##opt
396 #define test_opt(sb, opt)		(EXT2_SB(sb)->s_mount_opt & \
397 					 EXT2_MOUNT_##opt)
398 /*
399  * Maximal mount counts between two filesystem checks
400  */
401 #define EXT2_DFL_MAX_MNT_COUNT		20	/* Allow 20 mounts */
402 #define EXT2_DFL_CHECKINTERVAL		0	/* Don't use interval check */
403 
404 /*
405  * Behaviour when detecting errors
406  */
407 #define EXT2_ERRORS_CONTINUE		1	/* Continue execution */
408 #define EXT2_ERRORS_RO			2	/* Remount fs read-only */
409 #define EXT2_ERRORS_PANIC		3	/* Panic */
410 #define EXT2_ERRORS_DEFAULT		EXT2_ERRORS_CONTINUE
411 
412 /*
413  * Structure of the super block
414  */
415 struct ext2_super_block {
416 	__le32	s_inodes_count;		/* Inodes count */
417 	__le32	s_blocks_count;		/* Blocks count */
418 	__le32	s_r_blocks_count;	/* Reserved blocks count */
419 	__le32	s_free_blocks_count;	/* Free blocks count */
420 	__le32	s_free_inodes_count;	/* Free inodes count */
421 	__le32	s_first_data_block;	/* First Data Block */
422 	__le32	s_log_block_size;	/* Block size */
423 	__le32	s_log_frag_size;	/* Fragment size */
424 	__le32	s_blocks_per_group;	/* # Blocks per group */
425 	__le32	s_frags_per_group;	/* # Fragments per group */
426 	__le32	s_inodes_per_group;	/* # Inodes per group */
427 	__le32	s_mtime;		/* Mount time */
428 	__le32	s_wtime;		/* Write time */
429 	__le16	s_mnt_count;		/* Mount count */
430 	__le16	s_max_mnt_count;	/* Maximal mount count */
431 	__le16	s_magic;		/* Magic signature */
432 	__le16	s_state;		/* File system state */
433 	__le16	s_errors;		/* Behaviour when detecting errors */
434 	__le16	s_minor_rev_level; 	/* minor revision level */
435 	__le32	s_lastcheck;		/* time of last check */
436 	__le32	s_checkinterval;	/* max. time between checks */
437 	__le32	s_creator_os;		/* OS */
438 	__le32	s_rev_level;		/* Revision level */
439 	__le16	s_def_resuid;		/* Default uid for reserved blocks */
440 	__le16	s_def_resgid;		/* Default gid for reserved blocks */
441 	/*
442 	 * These fields are for EXT2_DYNAMIC_REV superblocks only.
443 	 *
444 	 * Note: the difference between the compatible feature set and
445 	 * the incompatible feature set is that if there is a bit set
446 	 * in the incompatible feature set that the kernel doesn't
447 	 * know about, it should refuse to mount the filesystem.
448 	 *
449 	 * e2fsck's requirements are more strict; if it doesn't know
450 	 * about a feature in either the compatible or incompatible
451 	 * feature set, it must abort and not try to meddle with
452 	 * things it doesn't understand...
453 	 */
454 	__le32	s_first_ino; 		/* First non-reserved inode */
455 	__le16   s_inode_size; 		/* size of inode structure */
456 	__le16	s_block_group_nr; 	/* block group # of this superblock */
457 	__le32	s_feature_compat; 	/* compatible feature set */
458 	__le32	s_feature_incompat; 	/* incompatible feature set */
459 	__le32	s_feature_ro_compat; 	/* readonly-compatible feature set */
460 	__u8	s_uuid[16];		/* 128-bit uuid for volume */
461 	char	s_volume_name[16]; 	/* volume name */
462 	char	s_last_mounted[64]; 	/* directory where last mounted */
463 	__le32	s_algorithm_usage_bitmap; /* For compression */
464 	/*
465 	 * Performance hints.  Directory preallocation should only
466 	 * happen if the EXT2_COMPAT_PREALLOC flag is on.
467 	 */
468 	__u8	s_prealloc_blocks;	/* Nr of blocks to try to preallocate*/
469 	__u8	s_prealloc_dir_blocks;	/* Nr to preallocate for dirs */
470 	__u16	s_padding1;
471 	/*
472 	 * Journaling support valid if EXT3_FEATURE_COMPAT_HAS_JOURNAL set.
473 	 */
474 	__u8	s_journal_uuid[16];	/* uuid of journal superblock */
475 	__u32	s_journal_inum;		/* inode number of journal file */
476 	__u32	s_journal_dev;		/* device number of journal file */
477 	__u32	s_last_orphan;		/* start of list of inodes to delete */
478 	__u32	s_hash_seed[4];		/* HTREE hash seed */
479 	__u8	s_def_hash_version;	/* Default hash version to use */
480 	__u8	s_reserved_char_pad;
481 	__u16	s_reserved_word_pad;
482 	__le32	s_default_mount_opts;
483  	__le32	s_first_meta_bg; 	/* First metablock block group */
484 	__u32	s_reserved[190];	/* Padding to the end of the block */
485 };
486 
487 /*
488  * Codes for operating systems
489  */
490 #define EXT2_OS_LINUX		0
491 #define EXT2_OS_HURD		1
492 #define EXT2_OS_MASIX		2
493 #define EXT2_OS_FREEBSD		3
494 #define EXT2_OS_LITES		4
495 
496 /*
497  * Revision levels
498  */
499 #define EXT2_GOOD_OLD_REV	0	/* The good old (original) format */
500 #define EXT2_DYNAMIC_REV	1 	/* V2 format w/ dynamic inode sizes */
501 
502 #define EXT2_CURRENT_REV	EXT2_GOOD_OLD_REV
503 #define EXT2_MAX_SUPP_REV	EXT2_DYNAMIC_REV
504 
505 #define EXT2_GOOD_OLD_INODE_SIZE 128
506 
507 /*
508  * Feature set definitions
509  */
510 
511 #define EXT2_HAS_COMPAT_FEATURE(sb,mask)			\
512 	( EXT2_SB(sb)->s_es->s_feature_compat & cpu_to_le32(mask) )
513 #define EXT2_HAS_RO_COMPAT_FEATURE(sb,mask)			\
514 	( EXT2_SB(sb)->s_es->s_feature_ro_compat & cpu_to_le32(mask) )
515 #define EXT2_HAS_INCOMPAT_FEATURE(sb,mask)			\
516 	( EXT2_SB(sb)->s_es->s_feature_incompat & cpu_to_le32(mask) )
517 #define EXT2_SET_COMPAT_FEATURE(sb,mask)			\
518 	EXT2_SB(sb)->s_es->s_feature_compat |= cpu_to_le32(mask)
519 #define EXT2_SET_RO_COMPAT_FEATURE(sb,mask)			\
520 	EXT2_SB(sb)->s_es->s_feature_ro_compat |= cpu_to_le32(mask)
521 #define EXT2_SET_INCOMPAT_FEATURE(sb,mask)			\
522 	EXT2_SB(sb)->s_es->s_feature_incompat |= cpu_to_le32(mask)
523 #define EXT2_CLEAR_COMPAT_FEATURE(sb,mask)			\
524 	EXT2_SB(sb)->s_es->s_feature_compat &= ~cpu_to_le32(mask)
525 #define EXT2_CLEAR_RO_COMPAT_FEATURE(sb,mask)			\
526 	EXT2_SB(sb)->s_es->s_feature_ro_compat &= ~cpu_to_le32(mask)
527 #define EXT2_CLEAR_INCOMPAT_FEATURE(sb,mask)			\
528 	EXT2_SB(sb)->s_es->s_feature_incompat &= ~cpu_to_le32(mask)
529 
530 #define EXT2_FEATURE_COMPAT_DIR_PREALLOC	0x0001
531 #define EXT2_FEATURE_COMPAT_IMAGIC_INODES	0x0002
532 #define EXT3_FEATURE_COMPAT_HAS_JOURNAL		0x0004
533 #define EXT2_FEATURE_COMPAT_EXT_ATTR		0x0008
534 #define EXT2_FEATURE_COMPAT_RESIZE_INO		0x0010
535 #define EXT2_FEATURE_COMPAT_DIR_INDEX		0x0020
536 #define EXT2_FEATURE_COMPAT_ANY			0xffffffff
537 
538 #define EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER	0x0001
539 #define EXT2_FEATURE_RO_COMPAT_LARGE_FILE	0x0002
540 #define EXT2_FEATURE_RO_COMPAT_BTREE_DIR	0x0004
541 #define EXT2_FEATURE_RO_COMPAT_ANY		0xffffffff
542 
543 #define EXT2_FEATURE_INCOMPAT_COMPRESSION	0x0001
544 #define EXT2_FEATURE_INCOMPAT_FILETYPE		0x0002
545 #define EXT3_FEATURE_INCOMPAT_RECOVER		0x0004
546 #define EXT3_FEATURE_INCOMPAT_JOURNAL_DEV	0x0008
547 #define EXT2_FEATURE_INCOMPAT_META_BG		0x0010
548 #define EXT2_FEATURE_INCOMPAT_ANY		0xffffffff
549 
550 #define EXT2_FEATURE_COMPAT_SUPP	EXT2_FEATURE_COMPAT_EXT_ATTR
551 #define EXT2_FEATURE_INCOMPAT_SUPP	(EXT2_FEATURE_INCOMPAT_FILETYPE| \
552 					 EXT2_FEATURE_INCOMPAT_META_BG)
553 #define EXT2_FEATURE_RO_COMPAT_SUPP	(EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER| \
554 					 EXT2_FEATURE_RO_COMPAT_LARGE_FILE| \
555 					 EXT2_FEATURE_RO_COMPAT_BTREE_DIR)
556 #define EXT2_FEATURE_RO_COMPAT_UNSUPPORTED	~EXT2_FEATURE_RO_COMPAT_SUPP
557 #define EXT2_FEATURE_INCOMPAT_UNSUPPORTED	~EXT2_FEATURE_INCOMPAT_SUPP
558 
559 /*
560  * Default values for user and/or group using reserved blocks
561  */
562 #define	EXT2_DEF_RESUID		0
563 #define	EXT2_DEF_RESGID		0
564 
565 /*
566  * Default mount options
567  */
568 #define EXT2_DEFM_DEBUG		0x0001
569 #define EXT2_DEFM_BSDGROUPS	0x0002
570 #define EXT2_DEFM_XATTR_USER	0x0004
571 #define EXT2_DEFM_ACL		0x0008
572 #define EXT2_DEFM_UID16		0x0010
573     /* Not used by ext2, but reserved for use by ext3 */
574 #define EXT3_DEFM_JMODE		0x0060
575 #define EXT3_DEFM_JMODE_DATA	0x0020
576 #define EXT3_DEFM_JMODE_ORDERED	0x0040
577 #define EXT3_DEFM_JMODE_WBACK	0x0060
578 
579 /*
580  * Structure of a directory entry
581  */
582 
583 struct ext2_dir_entry {
584 	__le32	inode;			/* Inode number */
585 	__le16	rec_len;		/* Directory entry length */
586 	__le16	name_len;		/* Name length */
587 	char	name[];			/* File name, up to EXT2_NAME_LEN */
588 };
589 
590 /*
591  * The new version of the directory entry.  Since EXT2 structures are
592  * stored in intel byte order, and the name_len field could never be
593  * bigger than 255 chars, it's safe to reclaim the extra byte for the
594  * file_type field.
595  */
596 struct ext2_dir_entry_2 {
597 	__le32	inode;			/* Inode number */
598 	__le16	rec_len;		/* Directory entry length */
599 	__u8	name_len;		/* Name length */
600 	__u8	file_type;
601 	char	name[];			/* File name, up to EXT2_NAME_LEN */
602 };
603 
604 /*
605  * Ext2 directory file types.  Only the low 3 bits are used.  The
606  * other bits are reserved for now.
607  */
608 enum {
609 	EXT2_FT_UNKNOWN		= 0,
610 	EXT2_FT_REG_FILE	= 1,
611 	EXT2_FT_DIR		= 2,
612 	EXT2_FT_CHRDEV		= 3,
613 	EXT2_FT_BLKDEV		= 4,
614 	EXT2_FT_FIFO		= 5,
615 	EXT2_FT_SOCK		= 6,
616 	EXT2_FT_SYMLINK		= 7,
617 	EXT2_FT_MAX
618 };
619 
620 /*
621  * EXT2_DIR_PAD defines the directory entries boundaries
622  *
623  * NOTE: It must be a multiple of 4
624  */
625 #define EXT2_DIR_PAD		 	4
626 #define EXT2_DIR_ROUND 			(EXT2_DIR_PAD - 1)
627 #define EXT2_DIR_REC_LEN(name_len)	(((name_len) + 8 + EXT2_DIR_ROUND) & \
628 					 ~EXT2_DIR_ROUND)
629 #define EXT2_MAX_REC_LEN		((1<<16)-1)
630 
631 static inline void verify_offsets(void)
632 {
633 #define A(x,y) BUILD_BUG_ON(x != offsetof(struct ext2_super_block, y));
634 	A(EXT2_SB_MAGIC_OFFSET, s_magic);
635 	A(EXT2_SB_BLOCKS_OFFSET, s_blocks_count);
636 	A(EXT2_SB_BSIZE_OFFSET, s_log_block_size);
637 #undef A
638 }
639 
640 /*
641  * ext2 mount options
642  */
643 struct ext2_mount_options {
644 	unsigned long s_mount_opt;
645 	kuid_t s_resuid;
646 	kgid_t s_resgid;
647 };
648 
649 /*
650  * second extended file system inode data in memory
651  */
652 struct ext2_inode_info {
653 	__le32	i_data[15];
654 	__u32	i_flags;
655 	__u32	i_faddr;
656 	__u8	i_frag_no;
657 	__u8	i_frag_size;
658 	__u16	i_state;
659 	__u32	i_file_acl;
660 	__u32	i_dir_acl;
661 	__u32	i_dtime;
662 
663 	/*
664 	 * i_block_group is the number of the block group which contains
665 	 * this file's inode.  Constant across the lifetime of the inode,
666 	 * it is used for making block allocation decisions - we try to
667 	 * place a file's data blocks near its inode block, and new inodes
668 	 * near to their parent directory's inode.
669 	 */
670 	__u32	i_block_group;
671 
672 	/* block reservation info */
673 	struct ext2_block_alloc_info *i_block_alloc_info;
674 
675 	__u32	i_dir_start_lookup;
676 #ifdef CONFIG_EXT2_FS_XATTR
677 	/*
678 	 * Extended attributes can be read independently of the main file
679 	 * data. Taking i_mutex even when reading would cause contention
680 	 * between readers of EAs and writers of regular file data, so
681 	 * instead we synchronize on xattr_sem when reading or changing
682 	 * EAs.
683 	 */
684 	struct rw_semaphore xattr_sem;
685 #endif
686 	rwlock_t i_meta_lock;
687 
688 	/*
689 	 * truncate_mutex is for serialising ext2_truncate() against
690 	 * ext2_getblock().  It also protects the internals of the inode's
691 	 * reservation data structures: ext2_reserve_window and
692 	 * ext2_reserve_window_node.
693 	 */
694 	struct mutex truncate_mutex;
695 	struct inode	vfs_inode;
696 	struct list_head i_orphan;	/* unlinked but open inodes */
697 #ifdef CONFIG_QUOTA
698 	struct dquot *i_dquot[MAXQUOTAS];
699 #endif
700 };
701 
702 /*
703  * Inode dynamic state flags
704  */
705 #define EXT2_STATE_NEW			0x00000001 /* inode is newly created */
706 
707 
708 /*
709  * Function prototypes
710  */
711 
712 /*
713  * Ok, these declarations are also in <linux/kernel.h> but none of the
714  * ext2 source programs needs to include it so they are duplicated here.
715  */
716 
717 static inline struct ext2_inode_info *EXT2_I(struct inode *inode)
718 {
719 	return container_of(inode, struct ext2_inode_info, vfs_inode);
720 }
721 
722 /* balloc.c */
723 extern int ext2_bg_has_super(struct super_block *sb, int group);
724 extern unsigned long ext2_bg_num_gdb(struct super_block *sb, int group);
725 extern ext2_fsblk_t ext2_new_block(struct inode *, unsigned long, int *);
726 extern ext2_fsblk_t ext2_new_blocks(struct inode *, unsigned long,
727 				unsigned long *, int *);
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 void ext2_check_blocks_bitmap (struct super_block *);
733 extern struct ext2_group_desc * ext2_get_group_desc(struct super_block * sb,
734 						    unsigned int block_group,
735 						    struct buffer_head ** bh);
736 extern void ext2_discard_reservation (struct inode *);
737 extern int ext2_should_retry_alloc(struct super_block *sb, int *retries);
738 extern void ext2_init_block_alloc_info(struct inode *);
739 extern void ext2_rsv_window_add(struct super_block *sb, struct ext2_reserve_window_node *rsv);
740 
741 /* dir.c */
742 extern int ext2_add_link (struct dentry *, struct inode *);
743 extern ino_t ext2_inode_by_name(struct inode *, struct qstr *);
744 extern int ext2_make_empty(struct inode *, struct inode *);
745 extern struct ext2_dir_entry_2 * ext2_find_entry (struct inode *,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 
751 /* ialloc.c */
752 extern struct inode * ext2_new_inode (struct inode *, umode_t, const struct qstr *);
753 extern void ext2_free_inode (struct inode *);
754 extern unsigned long ext2_count_free_inodes (struct super_block *);
755 extern void ext2_check_inodes_bitmap (struct super_block *);
756 extern unsigned long ext2_count_free (struct buffer_head *, unsigned);
757 
758 /* inode.c */
759 extern struct inode *ext2_iget (struct super_block *, unsigned long);
760 extern int ext2_write_inode (struct inode *, struct writeback_control *);
761 extern void ext2_evict_inode(struct inode *);
762 extern int ext2_get_block(struct inode *, sector_t, struct buffer_head *, int);
763 extern int ext2_setattr (struct dentry *, struct iattr *);
764 extern void ext2_set_inode_flags(struct inode *inode);
765 extern void ext2_get_inode_flags(struct ext2_inode_info *);
766 extern int ext2_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
767 		       u64 start, u64 len);
768 
769 /* ioctl.c */
770 extern long ext2_ioctl(struct file *, unsigned int, unsigned long);
771 extern long ext2_compat_ioctl(struct file *, unsigned int, unsigned long);
772 
773 /* namei.c */
774 struct dentry *ext2_get_parent(struct dentry *child);
775 
776 /* super.c */
777 extern __printf(3, 4)
778 void ext2_error(struct super_block *, const char *, const char *, ...);
779 extern __printf(3, 4)
780 void ext2_msg(struct super_block *, const char *, const char *, ...);
781 extern void ext2_update_dynamic_rev (struct super_block *sb);
782 extern void ext2_write_super (struct super_block *);
783 
784 /*
785  * Inodes and files operations
786  */
787 
788 /* dir.c */
789 extern const struct file_operations ext2_dir_operations;
790 
791 /* file.c */
792 extern int ext2_fsync(struct file *file, loff_t start, loff_t end,
793 		      int datasync);
794 extern const struct inode_operations ext2_file_inode_operations;
795 extern const struct file_operations ext2_file_operations;
796 
797 /* inode.c */
798 extern const struct address_space_operations ext2_aops;
799 extern const struct address_space_operations ext2_nobh_aops;
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 #define ext2_set_bit	__test_and_set_bit_le
817 #define ext2_clear_bit	__test_and_clear_bit_le
818 #define ext2_test_bit	test_bit_le
819 #define ext2_find_first_zero_bit	find_first_zero_bit_le
820 #define ext2_find_next_zero_bit		find_next_zero_bit_le
821