xref: /openbmc/linux/fs/ext2/ext2.h (revision 217188d9)
1  /* SPDX-License-Identifier: GPL-2.0 */
2  /*
3   * Copyright (C) 1992, 1993, 1994, 1995
4   * Remy Card (card@masi.ibp.fr)
5   * Laboratoire MASI - Institut Blaise Pascal
6   * Universite Pierre et Marie Curie (Paris VI)
7   *
8   *  from
9   *
10   *  linux/include/linux/minix_fs.h
11   *
12   *  Copyright (C) 1991, 1992  Linus Torvalds
13   */
14  #include <linux/fs.h>
15  #include <linux/ext2_fs.h>
16  #include <linux/blockgroup_lock.h>
17  #include <linux/percpu_counter.h>
18  #include <linux/rbtree.h>
19  
20  /* XXX Here for now... not interested in restructing headers JUST now */
21  
22  /* data type for block offset of block group */
23  typedef int ext2_grpblk_t;
24  
25  /* data type for filesystem-wide blocks number */
26  typedef unsigned long ext2_fsblk_t;
27  
28  #define E2FSBLK "%lu"
29  
30  struct ext2_reserve_window {
31  	ext2_fsblk_t		_rsv_start;	/* First byte reserved */
32  	ext2_fsblk_t		_rsv_end;	/* Last byte reserved or 0 */
33  };
34  
35  struct ext2_reserve_window_node {
36  	struct rb_node	 	rsv_node;
37  	__u32			rsv_goal_size;
38  	__u32			rsv_alloc_hit;
39  	struct ext2_reserve_window	rsv_window;
40  };
41  
42  struct ext2_block_alloc_info {
43  	/* information about reservation window */
44  	struct ext2_reserve_window_node	rsv_window_node;
45  	/*
46  	 * was i_next_alloc_block in ext2_inode_info
47  	 * is the logical (file-relative) number of the
48  	 * most-recently-allocated block in this file.
49  	 * We use this for detecting linearly ascending allocation requests.
50  	 */
51  	__u32			last_alloc_logical_block;
52  	/*
53  	 * Was i_next_alloc_goal in ext2_inode_info
54  	 * is the *physical* companion to i_next_alloc_block.
55  	 * it the the physical block number of the block which was most-recentl
56  	 * allocated to this file.  This give us the goal (target) for the next
57  	 * allocation when we detect linearly ascending requests.
58  	 */
59  	ext2_fsblk_t		last_alloc_physical_block;
60  };
61  
62  #define rsv_start rsv_window._rsv_start
63  #define rsv_end rsv_window._rsv_end
64  
65  struct mb_cache;
66  
67  /*
68   * second extended-fs super-block data in memory
69   */
70  struct ext2_sb_info {
71  	unsigned long s_frag_size;	/* Size of a fragment in bytes */
72  	unsigned long s_frags_per_block;/* Number of fragments per block */
73  	unsigned long s_inodes_per_block;/* Number of inodes per block */
74  	unsigned long s_frags_per_group;/* Number of fragments in a group */
75  	unsigned long s_blocks_per_group;/* Number of blocks in a group */
76  	unsigned long s_inodes_per_group;/* Number of inodes in a group */
77  	unsigned long s_itb_per_group;	/* Number of inode table blocks per group */
78  	unsigned long s_gdb_count;	/* Number of group descriptor blocks */
79  	unsigned long s_desc_per_block;	/* Number of group descriptors per block */
80  	unsigned long s_groups_count;	/* Number of groups in the fs */
81  	unsigned long s_overhead_last;  /* Last calculated overhead */
82  	unsigned long s_blocks_last;    /* Last seen block count */
83  	struct buffer_head * s_sbh;	/* Buffer containing the super block */
84  	struct ext2_super_block * s_es;	/* Pointer to the super block in the buffer */
85  	struct buffer_head ** s_group_desc;
86  	unsigned long  s_mount_opt;
87  	unsigned long s_sb_block;
88  	kuid_t s_resuid;
89  	kgid_t s_resgid;
90  	unsigned short s_mount_state;
91  	unsigned short s_pad;
92  	int s_addr_per_block_bits;
93  	int s_desc_per_block_bits;
94  	int s_inode_size;
95  	int s_first_ino;
96  	spinlock_t s_next_gen_lock;
97  	u32 s_next_generation;
98  	unsigned long s_dir_count;
99  	u8 *s_debts;
100  	struct percpu_counter s_freeblocks_counter;
101  	struct percpu_counter s_freeinodes_counter;
102  	struct percpu_counter s_dirs_counter;
103  	struct blockgroup_lock *s_blockgroup_lock;
104  	/* root of the per fs reservation window tree */
105  	spinlock_t s_rsv_window_lock;
106  	struct rb_root s_rsv_window_root;
107  	struct ext2_reserve_window_node s_rsv_window_head;
108  	/*
109  	 * s_lock protects against concurrent modifications of s_mount_state,
110  	 * s_blocks_last, s_overhead_last and the content of superblock's
111  	 * buffer pointed to by sbi->s_es.
112  	 *
113  	 * Note: It is used in ext2_show_options() to provide a consistent view
114  	 * of the mount options.
115  	 */
116  	spinlock_t s_lock;
117  	struct mb_cache *s_ea_block_cache;
118  	struct dax_device *s_daxdev;
119  };
120  
121  static inline spinlock_t *
122  sb_bgl_lock(struct ext2_sb_info *sbi, unsigned int block_group)
123  {
124  	return bgl_lock_ptr(sbi->s_blockgroup_lock, block_group);
125  }
126  
127  /*
128   * Define EXT2FS_DEBUG to produce debug messages
129   */
130  #undef EXT2FS_DEBUG
131  
132  /*
133   * Define EXT2_RESERVATION to reserve data blocks for expanding files
134   */
135  #define EXT2_DEFAULT_RESERVE_BLOCKS     8
136  /*max window size: 1024(direct blocks) + 3([t,d]indirect blocks) */
137  #define EXT2_MAX_RESERVE_BLOCKS         1027
138  #define EXT2_RESERVE_WINDOW_NOT_ALLOCATED 0
139  /*
140   * The second extended file system version
141   */
142  #define EXT2FS_DATE		"95/08/09"
143  #define EXT2FS_VERSION		"0.5b"
144  
145  /*
146   * Debug code
147   */
148  #ifdef EXT2FS_DEBUG
149  #	define ext2_debug(f, a...)	{ \
150  					printk ("EXT2-fs DEBUG (%s, %d): %s:", \
151  						__FILE__, __LINE__, __func__); \
152  				  	printk (f, ## a); \
153  					}
154  #else
155  #	define ext2_debug(f, a...)	/**/
156  #endif
157  
158  /*
159   * Special inode numbers
160   */
161  #define	EXT2_BAD_INO		 1	/* Bad blocks inode */
162  #define EXT2_ROOT_INO		 2	/* Root inode */
163  #define EXT2_BOOT_LOADER_INO	 5	/* Boot loader inode */
164  #define EXT2_UNDEL_DIR_INO	 6	/* Undelete directory inode */
165  
166  /* First non-reserved inode for old ext2 filesystems */
167  #define EXT2_GOOD_OLD_FIRST_INO	11
168  
169  static inline struct ext2_sb_info *EXT2_SB(struct super_block *sb)
170  {
171  	return sb->s_fs_info;
172  }
173  
174  /*
175   * Macro-instructions used to manage several block sizes
176   */
177  #define EXT2_MIN_BLOCK_SIZE		1024
178  #define	EXT2_MAX_BLOCK_SIZE		4096
179  #define EXT2_MIN_BLOCK_LOG_SIZE		  10
180  #define EXT2_BLOCK_SIZE(s)		((s)->s_blocksize)
181  #define	EXT2_ADDR_PER_BLOCK(s)		(EXT2_BLOCK_SIZE(s) / sizeof (__u32))
182  #define EXT2_BLOCK_SIZE_BITS(s)		((s)->s_blocksize_bits)
183  #define	EXT2_ADDR_PER_BLOCK_BITS(s)	(EXT2_SB(s)->s_addr_per_block_bits)
184  #define EXT2_INODE_SIZE(s)		(EXT2_SB(s)->s_inode_size)
185  #define EXT2_FIRST_INO(s)		(EXT2_SB(s)->s_first_ino)
186  
187  /*
188   * Macro-instructions used to manage fragments
189   */
190  #define EXT2_MIN_FRAG_SIZE		1024
191  #define	EXT2_MAX_FRAG_SIZE		4096
192  #define EXT2_MIN_FRAG_LOG_SIZE		  10
193  #define EXT2_FRAG_SIZE(s)		(EXT2_SB(s)->s_frag_size)
194  #define EXT2_FRAGS_PER_BLOCK(s)		(EXT2_SB(s)->s_frags_per_block)
195  
196  /*
197   * Structure of a blocks group descriptor
198   */
199  struct ext2_group_desc
200  {
201  	__le32	bg_block_bitmap;		/* Blocks bitmap block */
202  	__le32	bg_inode_bitmap;		/* Inodes bitmap block */
203  	__le32	bg_inode_table;		/* Inodes table block */
204  	__le16	bg_free_blocks_count;	/* Free blocks count */
205  	__le16	bg_free_inodes_count;	/* Free inodes count */
206  	__le16	bg_used_dirs_count;	/* Directories count */
207  	__le16	bg_pad;
208  	__le32	bg_reserved[3];
209  };
210  
211  /*
212   * Macro-instructions used to manage group descriptors
213   */
214  #define EXT2_BLOCKS_PER_GROUP(s)	(EXT2_SB(s)->s_blocks_per_group)
215  #define EXT2_DESC_PER_BLOCK(s)		(EXT2_SB(s)->s_desc_per_block)
216  #define EXT2_INODES_PER_GROUP(s)	(EXT2_SB(s)->s_inodes_per_group)
217  #define EXT2_DESC_PER_BLOCK_BITS(s)	(EXT2_SB(s)->s_desc_per_block_bits)
218  
219  /*
220   * Constants relative to the data blocks
221   */
222  #define	EXT2_NDIR_BLOCKS		12
223  #define	EXT2_IND_BLOCK			EXT2_NDIR_BLOCKS
224  #define	EXT2_DIND_BLOCK			(EXT2_IND_BLOCK + 1)
225  #define	EXT2_TIND_BLOCK			(EXT2_DIND_BLOCK + 1)
226  #define	EXT2_N_BLOCKS			(EXT2_TIND_BLOCK + 1)
227  
228  /*
229   * Inode flags (GETFLAGS/SETFLAGS)
230   */
231  #define	EXT2_SECRM_FL			FS_SECRM_FL	/* Secure deletion */
232  #define	EXT2_UNRM_FL			FS_UNRM_FL	/* Undelete */
233  #define	EXT2_COMPR_FL			FS_COMPR_FL	/* Compress file */
234  #define EXT2_SYNC_FL			FS_SYNC_FL	/* Synchronous updates */
235  #define EXT2_IMMUTABLE_FL		FS_IMMUTABLE_FL	/* Immutable file */
236  #define EXT2_APPEND_FL			FS_APPEND_FL	/* writes to file may only append */
237  #define EXT2_NODUMP_FL			FS_NODUMP_FL	/* do not dump file */
238  #define EXT2_NOATIME_FL			FS_NOATIME_FL	/* do not update atime */
239  /* Reserved for compression usage... */
240  #define EXT2_DIRTY_FL			FS_DIRTY_FL
241  #define EXT2_COMPRBLK_FL		FS_COMPRBLK_FL	/* One or more compressed clusters */
242  #define EXT2_NOCOMP_FL			FS_NOCOMP_FL	/* Don't compress */
243  #define EXT2_ECOMPR_FL			FS_ECOMPR_FL	/* Compression error */
244  /* End compression flags --- maybe not all used */
245  #define EXT2_BTREE_FL			FS_BTREE_FL	/* btree format dir */
246  #define EXT2_INDEX_FL			FS_INDEX_FL	/* hash-indexed directory */
247  #define EXT2_IMAGIC_FL			FS_IMAGIC_FL	/* AFS directory */
248  #define EXT2_JOURNAL_DATA_FL		FS_JOURNAL_DATA_FL /* Reserved for ext3 */
249  #define EXT2_NOTAIL_FL			FS_NOTAIL_FL	/* file tail should not be merged */
250  #define EXT2_DIRSYNC_FL			FS_DIRSYNC_FL	/* dirsync behaviour (directories only) */
251  #define EXT2_TOPDIR_FL			FS_TOPDIR_FL	/* Top of directory hierarchies*/
252  #define EXT2_RESERVED_FL		FS_RESERVED_FL	/* reserved for ext2 lib */
253  
254  #define EXT2_FL_USER_VISIBLE		FS_FL_USER_VISIBLE	/* User visible flags */
255  #define EXT2_FL_USER_MODIFIABLE		FS_FL_USER_MODIFIABLE	/* User modifiable flags */
256  
257  /* Flags that should be inherited by new inodes from their parent. */
258  #define EXT2_FL_INHERITED (EXT2_SECRM_FL | EXT2_UNRM_FL | EXT2_COMPR_FL |\
259  			   EXT2_SYNC_FL | EXT2_NODUMP_FL |\
260  			   EXT2_NOATIME_FL | EXT2_COMPRBLK_FL |\
261  			   EXT2_NOCOMP_FL | EXT2_JOURNAL_DATA_FL |\
262  			   EXT2_NOTAIL_FL | EXT2_DIRSYNC_FL)
263  
264  /* Flags that are appropriate for regular files (all but dir-specific ones). */
265  #define EXT2_REG_FLMASK (~(EXT2_DIRSYNC_FL | EXT2_TOPDIR_FL))
266  
267  /* Flags that are appropriate for non-directories/regular files. */
268  #define EXT2_OTHER_FLMASK (EXT2_NODUMP_FL | EXT2_NOATIME_FL)
269  
270  /* Mask out flags that are inappropriate for the given type of inode. */
271  static inline __u32 ext2_mask_flags(umode_t mode, __u32 flags)
272  {
273  	if (S_ISDIR(mode))
274  		return flags;
275  	else if (S_ISREG(mode))
276  		return flags & EXT2_REG_FLMASK;
277  	else
278  		return flags & EXT2_OTHER_FLMASK;
279  }
280  
281  /*
282   * ioctl commands
283   */
284  #define	EXT2_IOC_GETFLAGS		FS_IOC_GETFLAGS
285  #define	EXT2_IOC_SETFLAGS		FS_IOC_SETFLAGS
286  #define	EXT2_IOC_GETVERSION		FS_IOC_GETVERSION
287  #define	EXT2_IOC_SETVERSION		FS_IOC_SETVERSION
288  #define	EXT2_IOC_GETRSVSZ		_IOR('f', 5, long)
289  #define	EXT2_IOC_SETRSVSZ		_IOW('f', 6, long)
290  
291  /*
292   * ioctl commands in 32 bit emulation
293   */
294  #define EXT2_IOC32_GETFLAGS		FS_IOC32_GETFLAGS
295  #define EXT2_IOC32_SETFLAGS		FS_IOC32_SETFLAGS
296  #define EXT2_IOC32_GETVERSION		FS_IOC32_GETVERSION
297  #define EXT2_IOC32_SETVERSION		FS_IOC32_SETVERSION
298  
299  /*
300   * Structure of an inode on the disk
301   */
302  struct ext2_inode {
303  	__le16	i_mode;		/* File mode */
304  	__le16	i_uid;		/* Low 16 bits of Owner Uid */
305  	__le32	i_size;		/* Size in bytes */
306  	__le32	i_atime;	/* Access time */
307  	__le32	i_ctime;	/* Creation time */
308  	__le32	i_mtime;	/* Modification time */
309  	__le32	i_dtime;	/* Deletion Time */
310  	__le16	i_gid;		/* Low 16 bits of Group Id */
311  	__le16	i_links_count;	/* Links count */
312  	__le32	i_blocks;	/* Blocks count */
313  	__le32	i_flags;	/* File flags */
314  	union {
315  		struct {
316  			__le32  l_i_reserved1;
317  		} linux1;
318  		struct {
319  			__le32  h_i_translator;
320  		} hurd1;
321  		struct {
322  			__le32  m_i_reserved1;
323  		} masix1;
324  	} osd1;				/* OS dependent 1 */
325  	__le32	i_block[EXT2_N_BLOCKS];/* Pointers to blocks */
326  	__le32	i_generation;	/* File version (for NFS) */
327  	__le32	i_file_acl;	/* File ACL */
328  	__le32	i_dir_acl;	/* Directory ACL */
329  	__le32	i_faddr;	/* Fragment address */
330  	union {
331  		struct {
332  			__u8	l_i_frag;	/* Fragment number */
333  			__u8	l_i_fsize;	/* Fragment size */
334  			__u16	i_pad1;
335  			__le16	l_i_uid_high;	/* these 2 fields    */
336  			__le16	l_i_gid_high;	/* were reserved2[0] */
337  			__u32	l_i_reserved2;
338  		} linux2;
339  		struct {
340  			__u8	h_i_frag;	/* Fragment number */
341  			__u8	h_i_fsize;	/* Fragment size */
342  			__le16	h_i_mode_high;
343  			__le16	h_i_uid_high;
344  			__le16	h_i_gid_high;
345  			__le32	h_i_author;
346  		} hurd2;
347  		struct {
348  			__u8	m_i_frag;	/* Fragment number */
349  			__u8	m_i_fsize;	/* Fragment size */
350  			__u16	m_pad1;
351  			__u32	m_i_reserved2[2];
352  		} masix2;
353  	} osd2;				/* OS dependent 2 */
354  };
355  
356  #define i_size_high	i_dir_acl
357  
358  #define i_reserved1	osd1.linux1.l_i_reserved1
359  #define i_frag		osd2.linux2.l_i_frag
360  #define i_fsize		osd2.linux2.l_i_fsize
361  #define i_uid_low	i_uid
362  #define i_gid_low	i_gid
363  #define i_uid_high	osd2.linux2.l_i_uid_high
364  #define i_gid_high	osd2.linux2.l_i_gid_high
365  #define i_reserved2	osd2.linux2.l_i_reserved2
366  
367  /*
368   * File system states
369   */
370  #define	EXT2_VALID_FS			0x0001	/* Unmounted cleanly */
371  #define	EXT2_ERROR_FS			0x0002	/* Errors detected */
372  #define	EFSCORRUPTED			EUCLEAN	/* Filesystem is corrupted */
373  
374  /*
375   * Mount flags
376   */
377  #define EXT2_MOUNT_CHECK		0x000001  /* Do mount-time checks */
378  #define EXT2_MOUNT_OLDALLOC		0x000002  /* Don't use the new Orlov allocator */
379  #define EXT2_MOUNT_GRPID		0x000004  /* Create files with directory's group */
380  #define EXT2_MOUNT_DEBUG		0x000008  /* Some debugging messages */
381  #define EXT2_MOUNT_ERRORS_CONT		0x000010  /* Continue on errors */
382  #define EXT2_MOUNT_ERRORS_RO		0x000020  /* Remount fs ro on errors */
383  #define EXT2_MOUNT_ERRORS_PANIC		0x000040  /* Panic on errors */
384  #define EXT2_MOUNT_MINIX_DF		0x000080  /* Mimics the Minix statfs */
385  #define EXT2_MOUNT_NOBH			0x000100  /* No buffer_heads */
386  #define EXT2_MOUNT_NO_UID32		0x000200  /* Disable 32-bit UIDs */
387  #define EXT2_MOUNT_XATTR_USER		0x004000  /* Extended user attributes */
388  #define EXT2_MOUNT_POSIX_ACL		0x008000  /* POSIX Access Control Lists */
389  #define EXT2_MOUNT_XIP			0x010000  /* Obsolete, use DAX */
390  #define EXT2_MOUNT_USRQUOTA		0x020000  /* user quota */
391  #define EXT2_MOUNT_GRPQUOTA		0x040000  /* group quota */
392  #define EXT2_MOUNT_RESERVATION		0x080000  /* Preallocation */
393  #ifdef CONFIG_FS_DAX
394  #define EXT2_MOUNT_DAX			0x100000  /* Direct Access */
395  #else
396  #define EXT2_MOUNT_DAX			0
397  #endif
398  
399  
400  #define clear_opt(o, opt)		o &= ~EXT2_MOUNT_##opt
401  #define set_opt(o, opt)			o |= EXT2_MOUNT_##opt
402  #define test_opt(sb, opt)		(EXT2_SB(sb)->s_mount_opt & \
403  					 EXT2_MOUNT_##opt)
404  /*
405   * Maximal mount counts between two filesystem checks
406   */
407  #define EXT2_DFL_MAX_MNT_COUNT		20	/* Allow 20 mounts */
408  #define EXT2_DFL_CHECKINTERVAL		0	/* Don't use interval check */
409  
410  /*
411   * Behaviour when detecting errors
412   */
413  #define EXT2_ERRORS_CONTINUE		1	/* Continue execution */
414  #define EXT2_ERRORS_RO			2	/* Remount fs read-only */
415  #define EXT2_ERRORS_PANIC		3	/* Panic */
416  #define EXT2_ERRORS_DEFAULT		EXT2_ERRORS_CONTINUE
417  
418  /*
419   * Structure of the super block
420   */
421  struct ext2_super_block {
422  	__le32	s_inodes_count;		/* Inodes count */
423  	__le32	s_blocks_count;		/* Blocks count */
424  	__le32	s_r_blocks_count;	/* Reserved blocks count */
425  	__le32	s_free_blocks_count;	/* Free blocks count */
426  	__le32	s_free_inodes_count;	/* Free inodes count */
427  	__le32	s_first_data_block;	/* First Data Block */
428  	__le32	s_log_block_size;	/* Block size */
429  	__le32	s_log_frag_size;	/* Fragment size */
430  	__le32	s_blocks_per_group;	/* # Blocks per group */
431  	__le32	s_frags_per_group;	/* # Fragments per group */
432  	__le32	s_inodes_per_group;	/* # Inodes per group */
433  	__le32	s_mtime;		/* Mount time */
434  	__le32	s_wtime;		/* Write time */
435  	__le16	s_mnt_count;		/* Mount count */
436  	__le16	s_max_mnt_count;	/* Maximal mount count */
437  	__le16	s_magic;		/* Magic signature */
438  	__le16	s_state;		/* File system state */
439  	__le16	s_errors;		/* Behaviour when detecting errors */
440  	__le16	s_minor_rev_level; 	/* minor revision level */
441  	__le32	s_lastcheck;		/* time of last check */
442  	__le32	s_checkinterval;	/* max. time between checks */
443  	__le32	s_creator_os;		/* OS */
444  	__le32	s_rev_level;		/* Revision level */
445  	__le16	s_def_resuid;		/* Default uid for reserved blocks */
446  	__le16	s_def_resgid;		/* Default gid for reserved blocks */
447  	/*
448  	 * These fields are for EXT2_DYNAMIC_REV superblocks only.
449  	 *
450  	 * Note: the difference between the compatible feature set and
451  	 * the incompatible feature set is that if there is a bit set
452  	 * in the incompatible feature set that the kernel doesn't
453  	 * know about, it should refuse to mount the filesystem.
454  	 *
455  	 * e2fsck's requirements are more strict; if it doesn't know
456  	 * about a feature in either the compatible or incompatible
457  	 * feature set, it must abort and not try to meddle with
458  	 * things it doesn't understand...
459  	 */
460  	__le32	s_first_ino; 		/* First non-reserved inode */
461  	__le16   s_inode_size; 		/* size of inode structure */
462  	__le16	s_block_group_nr; 	/* block group # of this superblock */
463  	__le32	s_feature_compat; 	/* compatible feature set */
464  	__le32	s_feature_incompat; 	/* incompatible feature set */
465  	__le32	s_feature_ro_compat; 	/* readonly-compatible feature set */
466  	__u8	s_uuid[16];		/* 128-bit uuid for volume */
467  	char	s_volume_name[16]; 	/* volume name */
468  	char	s_last_mounted[64]; 	/* directory where last mounted */
469  	__le32	s_algorithm_usage_bitmap; /* For compression */
470  	/*
471  	 * Performance hints.  Directory preallocation should only
472  	 * happen if the EXT2_COMPAT_PREALLOC flag is on.
473  	 */
474  	__u8	s_prealloc_blocks;	/* Nr of blocks to try to preallocate*/
475  	__u8	s_prealloc_dir_blocks;	/* Nr to preallocate for dirs */
476  	__u16	s_padding1;
477  	/*
478  	 * Journaling support valid if EXT3_FEATURE_COMPAT_HAS_JOURNAL set.
479  	 */
480  	__u8	s_journal_uuid[16];	/* uuid of journal superblock */
481  	__u32	s_journal_inum;		/* inode number of journal file */
482  	__u32	s_journal_dev;		/* device number of journal file */
483  	__u32	s_last_orphan;		/* start of list of inodes to delete */
484  	__u32	s_hash_seed[4];		/* HTREE hash seed */
485  	__u8	s_def_hash_version;	/* Default hash version to use */
486  	__u8	s_reserved_char_pad;
487  	__u16	s_reserved_word_pad;
488  	__le32	s_default_mount_opts;
489   	__le32	s_first_meta_bg; 	/* First metablock block group */
490  	__u32	s_reserved[190];	/* Padding to the end of the block */
491  };
492  
493  /*
494   * Codes for operating systems
495   */
496  #define EXT2_OS_LINUX		0
497  #define EXT2_OS_HURD		1
498  #define EXT2_OS_MASIX		2
499  #define EXT2_OS_FREEBSD		3
500  #define EXT2_OS_LITES		4
501  
502  /*
503   * Revision levels
504   */
505  #define EXT2_GOOD_OLD_REV	0	/* The good old (original) format */
506  #define EXT2_DYNAMIC_REV	1 	/* V2 format w/ dynamic inode sizes */
507  
508  #define EXT2_CURRENT_REV	EXT2_GOOD_OLD_REV
509  #define EXT2_MAX_SUPP_REV	EXT2_DYNAMIC_REV
510  
511  #define EXT2_GOOD_OLD_INODE_SIZE 128
512  
513  /*
514   * Feature set definitions
515   */
516  
517  #define EXT2_HAS_COMPAT_FEATURE(sb,mask)			\
518  	( EXT2_SB(sb)->s_es->s_feature_compat & cpu_to_le32(mask) )
519  #define EXT2_HAS_RO_COMPAT_FEATURE(sb,mask)			\
520  	( EXT2_SB(sb)->s_es->s_feature_ro_compat & cpu_to_le32(mask) )
521  #define EXT2_HAS_INCOMPAT_FEATURE(sb,mask)			\
522  	( EXT2_SB(sb)->s_es->s_feature_incompat & cpu_to_le32(mask) )
523  #define EXT2_SET_COMPAT_FEATURE(sb,mask)			\
524  	EXT2_SB(sb)->s_es->s_feature_compat |= cpu_to_le32(mask)
525  #define EXT2_SET_RO_COMPAT_FEATURE(sb,mask)			\
526  	EXT2_SB(sb)->s_es->s_feature_ro_compat |= cpu_to_le32(mask)
527  #define EXT2_SET_INCOMPAT_FEATURE(sb,mask)			\
528  	EXT2_SB(sb)->s_es->s_feature_incompat |= cpu_to_le32(mask)
529  #define EXT2_CLEAR_COMPAT_FEATURE(sb,mask)			\
530  	EXT2_SB(sb)->s_es->s_feature_compat &= ~cpu_to_le32(mask)
531  #define EXT2_CLEAR_RO_COMPAT_FEATURE(sb,mask)			\
532  	EXT2_SB(sb)->s_es->s_feature_ro_compat &= ~cpu_to_le32(mask)
533  #define EXT2_CLEAR_INCOMPAT_FEATURE(sb,mask)			\
534  	EXT2_SB(sb)->s_es->s_feature_incompat &= ~cpu_to_le32(mask)
535  
536  #define EXT2_FEATURE_COMPAT_DIR_PREALLOC	0x0001
537  #define EXT2_FEATURE_COMPAT_IMAGIC_INODES	0x0002
538  #define EXT3_FEATURE_COMPAT_HAS_JOURNAL		0x0004
539  #define EXT2_FEATURE_COMPAT_EXT_ATTR		0x0008
540  #define EXT2_FEATURE_COMPAT_RESIZE_INO		0x0010
541  #define EXT2_FEATURE_COMPAT_DIR_INDEX		0x0020
542  #define EXT2_FEATURE_COMPAT_ANY			0xffffffff
543  
544  #define EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER	0x0001
545  #define EXT2_FEATURE_RO_COMPAT_LARGE_FILE	0x0002
546  #define EXT2_FEATURE_RO_COMPAT_BTREE_DIR	0x0004
547  #define EXT2_FEATURE_RO_COMPAT_ANY		0xffffffff
548  
549  #define EXT2_FEATURE_INCOMPAT_COMPRESSION	0x0001
550  #define EXT2_FEATURE_INCOMPAT_FILETYPE		0x0002
551  #define EXT3_FEATURE_INCOMPAT_RECOVER		0x0004
552  #define EXT3_FEATURE_INCOMPAT_JOURNAL_DEV	0x0008
553  #define EXT2_FEATURE_INCOMPAT_META_BG		0x0010
554  #define EXT2_FEATURE_INCOMPAT_ANY		0xffffffff
555  
556  #define EXT2_FEATURE_COMPAT_SUPP	EXT2_FEATURE_COMPAT_EXT_ATTR
557  #define EXT2_FEATURE_INCOMPAT_SUPP	(EXT2_FEATURE_INCOMPAT_FILETYPE| \
558  					 EXT2_FEATURE_INCOMPAT_META_BG)
559  #define EXT2_FEATURE_RO_COMPAT_SUPP	(EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER| \
560  					 EXT2_FEATURE_RO_COMPAT_LARGE_FILE| \
561  					 EXT2_FEATURE_RO_COMPAT_BTREE_DIR)
562  #define EXT2_FEATURE_RO_COMPAT_UNSUPPORTED	~EXT2_FEATURE_RO_COMPAT_SUPP
563  #define EXT2_FEATURE_INCOMPAT_UNSUPPORTED	~EXT2_FEATURE_INCOMPAT_SUPP
564  
565  /*
566   * Default values for user and/or group using reserved blocks
567   */
568  #define	EXT2_DEF_RESUID		0
569  #define	EXT2_DEF_RESGID		0
570  
571  /*
572   * Default mount options
573   */
574  #define EXT2_DEFM_DEBUG		0x0001
575  #define EXT2_DEFM_BSDGROUPS	0x0002
576  #define EXT2_DEFM_XATTR_USER	0x0004
577  #define EXT2_DEFM_ACL		0x0008
578  #define EXT2_DEFM_UID16		0x0010
579      /* Not used by ext2, but reserved for use by ext3 */
580  #define EXT3_DEFM_JMODE		0x0060
581  #define EXT3_DEFM_JMODE_DATA	0x0020
582  #define EXT3_DEFM_JMODE_ORDERED	0x0040
583  #define EXT3_DEFM_JMODE_WBACK	0x0060
584  
585  /*
586   * Structure of a directory entry
587   */
588  
589  struct ext2_dir_entry {
590  	__le32	inode;			/* Inode number */
591  	__le16	rec_len;		/* Directory entry length */
592  	__le16	name_len;		/* Name length */
593  	char	name[];			/* File name, up to EXT2_NAME_LEN */
594  };
595  
596  /*
597   * The new version of the directory entry.  Since EXT2 structures are
598   * stored in intel byte order, and the name_len field could never be
599   * bigger than 255 chars, it's safe to reclaim the extra byte for the
600   * file_type field.
601   */
602  struct ext2_dir_entry_2 {
603  	__le32	inode;			/* Inode number */
604  	__le16	rec_len;		/* Directory entry length */
605  	__u8	name_len;		/* Name length */
606  	__u8	file_type;
607  	char	name[];			/* File name, up to EXT2_NAME_LEN */
608  };
609  
610  /*
611   * Ext2 directory file types.  Only the low 3 bits are used.  The
612   * other bits are reserved for now.
613   */
614  enum {
615  	EXT2_FT_UNKNOWN		= 0,
616  	EXT2_FT_REG_FILE	= 1,
617  	EXT2_FT_DIR		= 2,
618  	EXT2_FT_CHRDEV		= 3,
619  	EXT2_FT_BLKDEV		= 4,
620  	EXT2_FT_FIFO		= 5,
621  	EXT2_FT_SOCK		= 6,
622  	EXT2_FT_SYMLINK		= 7,
623  	EXT2_FT_MAX
624  };
625  
626  /*
627   * EXT2_DIR_PAD defines the directory entries boundaries
628   *
629   * NOTE: It must be a multiple of 4
630   */
631  #define EXT2_DIR_PAD		 	4
632  #define EXT2_DIR_ROUND 			(EXT2_DIR_PAD - 1)
633  #define EXT2_DIR_REC_LEN(name_len)	(((name_len) + 8 + EXT2_DIR_ROUND) & \
634  					 ~EXT2_DIR_ROUND)
635  #define EXT2_MAX_REC_LEN		((1<<16)-1)
636  
637  static inline void verify_offsets(void)
638  {
639  #define A(x,y) BUILD_BUG_ON(x != offsetof(struct ext2_super_block, y));
640  	A(EXT2_SB_MAGIC_OFFSET, s_magic);
641  	A(EXT2_SB_BLOCKS_OFFSET, s_blocks_count);
642  	A(EXT2_SB_BSIZE_OFFSET, s_log_block_size);
643  #undef A
644  }
645  
646  /*
647   * ext2 mount options
648   */
649  struct ext2_mount_options {
650  	unsigned long s_mount_opt;
651  	kuid_t s_resuid;
652  	kgid_t s_resgid;
653  };
654  
655  /*
656   * second extended file system inode data in memory
657   */
658  struct ext2_inode_info {
659  	__le32	i_data[15];
660  	__u32	i_flags;
661  	__u32	i_faddr;
662  	__u8	i_frag_no;
663  	__u8	i_frag_size;
664  	__u16	i_state;
665  	__u32	i_file_acl;
666  	__u32	i_dir_acl;
667  	__u32	i_dtime;
668  
669  	/*
670  	 * i_block_group is the number of the block group which contains
671  	 * this file's inode.  Constant across the lifetime of the inode,
672  	 * it is used for making block allocation decisions - we try to
673  	 * place a file's data blocks near its inode block, and new inodes
674  	 * near to their parent directory's inode.
675  	 */
676  	__u32	i_block_group;
677  
678  	/* block reservation info */
679  	struct ext2_block_alloc_info *i_block_alloc_info;
680  
681  	__u32	i_dir_start_lookup;
682  #ifdef CONFIG_EXT2_FS_XATTR
683  	/*
684  	 * Extended attributes can be read independently of the main file
685  	 * data. Taking i_mutex even when reading would cause contention
686  	 * between readers of EAs and writers of regular file data, so
687  	 * instead we synchronize on xattr_sem when reading or changing
688  	 * EAs.
689  	 */
690  	struct rw_semaphore xattr_sem;
691  #endif
692  	rwlock_t i_meta_lock;
693  #ifdef CONFIG_FS_DAX
694  	struct rw_semaphore dax_sem;
695  #endif
696  
697  	/*
698  	 * truncate_mutex is for serialising ext2_truncate() against
699  	 * ext2_getblock().  It also protects the internals of the inode's
700  	 * reservation data structures: ext2_reserve_window and
701  	 * ext2_reserve_window_node.
702  	 */
703  	struct mutex truncate_mutex;
704  	struct inode	vfs_inode;
705  	struct list_head i_orphan;	/* unlinked but open inodes */
706  #ifdef CONFIG_QUOTA
707  	struct dquot *i_dquot[MAXQUOTAS];
708  #endif
709  };
710  
711  #ifdef CONFIG_FS_DAX
712  #define dax_sem_down_write(ext2_inode)	down_write(&(ext2_inode)->dax_sem)
713  #define dax_sem_up_write(ext2_inode)	up_write(&(ext2_inode)->dax_sem)
714  #else
715  #define dax_sem_down_write(ext2_inode)
716  #define dax_sem_up_write(ext2_inode)
717  #endif
718  
719  /*
720   * Inode dynamic state flags
721   */
722  #define EXT2_STATE_NEW			0x00000001 /* inode is newly created */
723  
724  
725  /*
726   * Function prototypes
727   */
728  
729  /*
730   * Ok, these declarations are also in <linux/kernel.h> but none of the
731   * ext2 source programs needs to include it so they are duplicated here.
732   */
733  
734  static inline struct ext2_inode_info *EXT2_I(struct inode *inode)
735  {
736  	return container_of(inode, struct ext2_inode_info, vfs_inode);
737  }
738  
739  /* balloc.c */
740  extern int ext2_bg_has_super(struct super_block *sb, int group);
741  extern unsigned long ext2_bg_num_gdb(struct super_block *sb, int group);
742  extern ext2_fsblk_t ext2_new_block(struct inode *, unsigned long, int *);
743  extern ext2_fsblk_t ext2_new_blocks(struct inode *, unsigned long,
744  				unsigned long *, int *);
745  extern int ext2_data_block_valid(struct ext2_sb_info *sbi, ext2_fsblk_t start_blk,
746  				 unsigned int count);
747  extern void ext2_free_blocks (struct inode *, unsigned long,
748  			      unsigned long);
749  extern unsigned long ext2_count_free_blocks (struct super_block *);
750  extern unsigned long ext2_count_dirs (struct super_block *);
751  extern struct ext2_group_desc * ext2_get_group_desc(struct super_block * sb,
752  						    unsigned int block_group,
753  						    struct buffer_head ** bh);
754  extern void ext2_discard_reservation (struct inode *);
755  extern int ext2_should_retry_alloc(struct super_block *sb, int *retries);
756  extern void ext2_init_block_alloc_info(struct inode *);
757  extern void ext2_rsv_window_add(struct super_block *sb, struct ext2_reserve_window_node *rsv);
758  
759  /* dir.c */
760  extern int ext2_add_link (struct dentry *, struct inode *);
761  extern ino_t ext2_inode_by_name(struct inode *, const struct qstr *);
762  extern int ext2_make_empty(struct inode *, struct inode *);
763  extern struct ext2_dir_entry_2 * ext2_find_entry (struct inode *,const struct qstr *, struct page **);
764  extern int ext2_delete_entry (struct ext2_dir_entry_2 *, struct page *);
765  extern int ext2_empty_dir (struct inode *);
766  extern struct ext2_dir_entry_2 * ext2_dotdot (struct inode *, struct page **);
767  extern void ext2_set_link(struct inode *, struct ext2_dir_entry_2 *, struct page *, struct inode *, int);
768  
769  /* ialloc.c */
770  extern struct inode * ext2_new_inode (struct inode *, umode_t, const struct qstr *);
771  extern void ext2_free_inode (struct inode *);
772  extern unsigned long ext2_count_free_inodes (struct super_block *);
773  extern unsigned long ext2_count_free (struct buffer_head *, unsigned);
774  
775  /* inode.c */
776  extern struct inode *ext2_iget (struct super_block *, unsigned long);
777  extern int ext2_write_inode (struct inode *, struct writeback_control *);
778  extern void ext2_evict_inode(struct inode *);
779  extern int ext2_get_block(struct inode *, sector_t, struct buffer_head *, int);
780  extern int ext2_setattr (struct dentry *, struct iattr *);
781  extern void ext2_set_inode_flags(struct inode *inode);
782  extern int ext2_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
783  		       u64 start, u64 len);
784  
785  /* ioctl.c */
786  extern long ext2_ioctl(struct file *, unsigned int, unsigned long);
787  extern long ext2_compat_ioctl(struct file *, unsigned int, unsigned long);
788  
789  /* namei.c */
790  struct dentry *ext2_get_parent(struct dentry *child);
791  
792  /* super.c */
793  extern __printf(3, 4)
794  void ext2_error(struct super_block *, const char *, const char *, ...);
795  extern __printf(3, 4)
796  void ext2_msg(struct super_block *, const char *, const char *, ...);
797  extern void ext2_update_dynamic_rev (struct super_block *sb);
798  extern void ext2_sync_super(struct super_block *sb, struct ext2_super_block *es,
799  			    int wait);
800  
801  /*
802   * Inodes and files operations
803   */
804  
805  /* dir.c */
806  extern const struct file_operations ext2_dir_operations;
807  
808  /* file.c */
809  extern int ext2_fsync(struct file *file, loff_t start, loff_t end,
810  		      int datasync);
811  extern const struct inode_operations ext2_file_inode_operations;
812  extern const struct file_operations ext2_file_operations;
813  
814  /* inode.c */
815  extern void ext2_set_file_ops(struct inode *inode);
816  extern const struct address_space_operations ext2_aops;
817  extern const struct address_space_operations ext2_nobh_aops;
818  extern const struct iomap_ops ext2_iomap_ops;
819  
820  /* namei.c */
821  extern const struct inode_operations ext2_dir_inode_operations;
822  extern const struct inode_operations ext2_special_inode_operations;
823  
824  /* symlink.c */
825  extern const struct inode_operations ext2_fast_symlink_inode_operations;
826  extern const struct inode_operations ext2_symlink_inode_operations;
827  
828  static inline ext2_fsblk_t
829  ext2_group_first_block_no(struct super_block *sb, unsigned long group_no)
830  {
831  	return group_no * (ext2_fsblk_t)EXT2_BLOCKS_PER_GROUP(sb) +
832  		le32_to_cpu(EXT2_SB(sb)->s_es->s_first_data_block);
833  }
834  
835  #define ext2_set_bit	__test_and_set_bit_le
836  #define ext2_clear_bit	__test_and_clear_bit_le
837  #define ext2_test_bit	test_bit_le
838  #define ext2_find_first_zero_bit	find_first_zero_bit_le
839  #define ext2_find_next_zero_bit		find_next_zero_bit_le
840