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TOMOYO Linux Cross Reference
Linux/fs/ext2/ext2.h

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

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