fs/aufs/branch.h

   1 /*
   2  * Copyright (C) 2005-2017 Junjiro R. Okajima
   3  *
   4  * This program, aufs is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  16  */
  17
  18 /*
  19  * branch filesystems and xino for them
  20  */
  21
  22 #ifndef __AUFS_BRANCH_H__
  23 #define __AUFS_BRANCH_H__
  24
  25 #ifdef __KERNEL__
  26
  27 #include <linux/mount.h>
  28 #include "dynop.h"
  29 #include "rwsem.h"
  30 #include "super.h"
  31
  32 /* ---------------------------------------------------------------------- */
  33
  34 /* a xino file */
  35 struct au_xino_file {
  36         struct file             *xi_file;
  37         struct {
  38                 spinlock_t              spin;
  39                 ino_t                   *array;
  40                 int                     total;
  41                 /* reserved for future use */
  42                 /* unsigned long        *bitmap; */
  43                 wait_queue_head_t       wqh;
  44         } xi_nondir;
  45
  46         /* todo: make xino files an array to support huge inode number */
  47
  48 #ifdef CONFIG_DEBUG_FS
  49         struct dentry            *xi_dbgaufs;
  50 #endif
  51 };
  52
  53 /* File-based Hierarchical Storage Management */
  54 struct au_br_fhsm {
  55 #ifdef CONFIG_AUFS_FHSM
  56         struct mutex            bf_lock;
  57         unsigned long           bf_jiffy;
  58         struct aufs_stfs        bf_stfs;
  59         int                     bf_readable;
  60 #endif
  61 };
  62
  63 /* members for writable branch only */
  64 enum {AuBrWh_BASE, AuBrWh_PLINK, AuBrWh_ORPH, AuBrWh_Last};
  65 struct au_wbr {
  66         struct au_rwsem         wbr_wh_rwsem;
  67         struct dentry           *wbr_wh[AuBrWh_Last];
  68         atomic_t                wbr_wh_running;
  69 #define wbr_whbase              wbr_wh[AuBrWh_BASE]     /* whiteout base */
  70 #define wbr_plink               wbr_wh[AuBrWh_PLINK]    /* pseudo-link dir */
  71 #define wbr_orph                wbr_wh[AuBrWh_ORPH]     /* dir for orphans */
  72
  73         /* mfs mode */
  74         unsigned long long      wbr_bytes;
  75 };
  76
  77 /* ext2 has 3 types of operations at least, ext3 has 4 */
  78 #define AuBrDynOp (AuDyLast * 4)
  79
  80 #ifdef CONFIG_AUFS_HFSNOTIFY
  81 /* support for asynchronous destruction */
  82 struct au_br_hfsnotify {
  83         struct fsnotify_group   *hfsn_group;
  84 };
  85 #endif
  86
  87 /* sysfs entries */
  88 struct au_brsysfs {
  89         char                    name[16];
  90         struct attribute        attr;
  91 };
  92
  93 enum {
  94         AuBrSysfs_BR,
  95         AuBrSysfs_BRID,
  96         AuBrSysfs_Last
  97 };
  98
  99 /* protected by superblock rwsem */
 100 struct au_branch {
 101         struct au_xino_file     br_xino;
 102
 103         aufs_bindex_t           br_id;
 104
 105         int                     br_perm;
 106         struct path             br_path;
 107         spinlock_t              br_dykey_lock;
 108         struct au_dykey         *br_dykey[AuBrDynOp];
 109         struct percpu_counter   br_count;
 110
 111         struct au_wbr           *br_wbr;
 112         struct au_br_fhsm       *br_fhsm;
 113
 114         /* xino truncation */
 115         atomic_t                br_xino_running;
 116
 117 #ifdef CONFIG_AUFS_HFSNOTIFY
 118         struct au_br_hfsnotify  *br_hfsn;
 119 #endif
 120
 121 #ifdef CONFIG_SYSFS
 122         /* entries under sysfs per mount-point */
 123         struct au_brsysfs       br_sysfs[AuBrSysfs_Last];
 124 #endif
 125 };
 126
 127 /* ---------------------------------------------------------------------- */
 128
 129 static inline struct vfsmount *au_br_mnt(struct au_branch *br)
 130 {
 131         return br->br_path.mnt;
 132 }
 133
 134 static inline struct dentry *au_br_dentry(struct au_branch *br)
 135 {
 136         return br->br_path.dentry;
 137 }
 138
 139 static inline struct super_block *au_br_sb(struct au_branch *br)
 140 {
 141         return au_br_mnt(br)->mnt_sb;
 142 }
 143
 144 static inline void au_br_get(struct au_branch *br)
 145 {
 146         percpu_counter_inc(&br->br_count);
 147 }
 148
 149 static inline void au_br_put(struct au_branch *br)
 150 {
 151         percpu_counter_dec(&br->br_count);
 152 }
 153
 154 static inline s64 au_br_count(struct au_branch *br)
 155 {
 156         return percpu_counter_sum(&br->br_count);
 157 }
 158
 159 static inline void au_br_count_init(struct au_branch *br)
 160 {
 161         percpu_counter_init(&br->br_count, 0, GFP_NOFS);
 162 }
 163
 164 static inline void au_br_count_fin(struct au_branch *br)
 165 {
 166         percpu_counter_destroy(&br->br_count);
 167 }
 168
 169 static inline int au_br_rdonly(struct au_branch *br)
 170 {
 171         return ((au_br_sb(br)->s_flags & MS_RDONLY)
 172                 || !au_br_writable(br->br_perm))
 173                 ? -EROFS : 0;
 174 }
 175
 176 static inline int au_br_hnotifyable(int brperm __maybe_unused)
 177 {
 178 #ifdef CONFIG_AUFS_HNOTIFY
 179         return !(brperm & AuBrPerm_RR);
 180 #else
 181         return 0;
 182 #endif
 183 }
 184
 185 static inline int au_br_test_oflag(int oflag, struct au_branch *br)
 186 {
 187         int err, exec_flag;
 188
 189         err = 0;
 190         exec_flag = oflag & __FMODE_EXEC;
 191         if (unlikely(exec_flag && path_noexec(&br->br_path)))
 192                 err = -EACCES;
 193
 194         return err;
 195 }
 196
 197 /* ---------------------------------------------------------------------- */
 198
 199 /* branch.c */
 200 struct au_sbinfo;
 201 void au_br_free(struct au_sbinfo *sinfo);
 202 int au_br_index(struct super_block *sb, aufs_bindex_t br_id);
 203 struct au_opt_add;
 204 int au_br_add(struct super_block *sb, struct au_opt_add *add, int remount);
 205 struct au_opt_del;
 206 int au_br_del(struct super_block *sb, struct au_opt_del *del, int remount);
 207 long au_ibusy_ioctl(struct file *file, unsigned long arg);
 208 #ifdef CONFIG_COMPAT
 209 long au_ibusy_compat_ioctl(struct file *file, unsigned long arg);
 210 #endif
 211 struct au_opt_mod;
 212 int au_br_mod(struct super_block *sb, struct au_opt_mod *mod, int remount,
 213               int *do_refresh);
 214 struct aufs_stfs;
 215 int au_br_stfs(struct au_branch *br, struct aufs_stfs *stfs);
 216
 217 /* xino.c */
 218 static const loff_t au_loff_max = LLONG_MAX;
 219
 220 int au_xib_trunc(struct super_block *sb);
 221 ssize_t xino_fread(vfs_readf_t func, struct file *file, void *buf, size_t size,
 222                    loff_t *pos);
 223 ssize_t xino_fwrite(vfs_writef_t func, struct file *file, void *buf,
 224                     size_t size, loff_t *pos);
 225 struct file *au_xino_create2(struct file *base_file, struct file *copy_src);
 226 struct file *au_xino_create(struct super_block *sb, char *fname, int silent);
 227 ino_t au_xino_new_ino(struct super_block *sb);
 228 void au_xino_delete_inode(struct inode *inode, const int unlinked);
 229 int au_xino_write(struct super_block *sb, aufs_bindex_t bindex, ino_t h_ino,
 230                   ino_t ino);
 231 int au_xino_read(struct super_block *sb, aufs_bindex_t bindex, ino_t h_ino,
 232                  ino_t *ino);
 233 int au_xino_br(struct super_block *sb, struct au_branch *br, ino_t hino,
 234                struct file *base_file, int do_test);
 235 int au_xino_trunc(struct super_block *sb, aufs_bindex_t bindex);
 236
 237 struct au_opt_xino;
 238 int au_xino_set(struct super_block *sb, struct au_opt_xino *xino, int remount);
 239 void au_xino_clr(struct super_block *sb);
 240 struct file *au_xino_def(struct super_block *sb);
 241 int au_xino_path(struct seq_file *seq, struct file *file);
 242
 243 void au_xinondir_leave(struct super_block *sb, aufs_bindex_t bindex,
 244                        ino_t h_ino, int idx);
 245 int au_xinondir_enter(struct super_block *sb, aufs_bindex_t bindex, ino_t h_ino,
 246                       int *idx);
 247
 248 /* ---------------------------------------------------------------------- */
 249
 250 /* Superblock to branch */
 251 static inline
 252 aufs_bindex_t au_sbr_id(struct super_block *sb, aufs_bindex_t bindex)
 253 {
 254         return au_sbr(sb, bindex)->br_id;
 255 }
 256
 257 static inline
 258 struct vfsmount *au_sbr_mnt(struct super_block *sb, aufs_bindex_t bindex)
 259 {
 260         return au_br_mnt(au_sbr(sb, bindex));
 261 }
 262
 263 static inline
 264 struct super_block *au_sbr_sb(struct super_block *sb, aufs_bindex_t bindex)
 265 {
 266         return au_br_sb(au_sbr(sb, bindex));
 267 }
 268
 269 static inline void au_sbr_get(struct super_block *sb, aufs_bindex_t bindex)
 270 {
 271         au_br_get(au_sbr(sb, bindex));
 272 }
 273
 274 static inline void au_sbr_put(struct super_block *sb, aufs_bindex_t bindex)
 275 {
 276         au_br_put(au_sbr(sb, bindex));
 277 }
 278
 279 static inline int au_sbr_perm(struct super_block *sb, aufs_bindex_t bindex)
 280 {
 281         return au_sbr(sb, bindex)->br_perm;
 282 }
 283
 284 static inline int au_sbr_whable(struct super_block *sb, aufs_bindex_t bindex)
 285 {
 286         return au_br_whable(au_sbr_perm(sb, bindex));
 287 }
 288
 289 /* ---------------------------------------------------------------------- */
 290
 291 /*
 292  * wbr_wh_read_lock, wbr_wh_write_lock
 293  * wbr_wh_read_unlock, wbr_wh_write_unlock, wbr_wh_downgrade_lock
 294  */
 295 AuSimpleRwsemFuncs(wbr_wh, struct au_wbr *wbr, &wbr->wbr_wh_rwsem);
 296
 297 #define WbrWhMustNoWaiters(wbr) AuRwMustNoWaiters(&wbr->wbr_wh_rwsem)
 298 #define WbrWhMustAnyLock(wbr)   AuRwMustAnyLock(&wbr->wbr_wh_rwsem)
 299 #define WbrWhMustWriteLock(wbr) AuRwMustWriteLock(&wbr->wbr_wh_rwsem)
 300
 301 /* ---------------------------------------------------------------------- */
 302
 303 #ifdef CONFIG_AUFS_FHSM
 304 static inline void au_br_fhsm_init(struct au_br_fhsm *brfhsm)
 305 {
 306         mutex_init(&brfhsm->bf_lock);
 307         brfhsm->bf_jiffy = 0;
 308         brfhsm->bf_readable = 0;
 309 }
 310
 311 static inline void au_br_fhsm_fin(struct au_br_fhsm *brfhsm)
 312 {
 313         mutex_destroy(&brfhsm->bf_lock);
 314 }
 315 #else
 316 AuStubVoid(au_br_fhsm_init, struct au_br_fhsm *brfhsm)
 317 AuStubVoid(au_br_fhsm_fin, struct au_br_fhsm *brfhsm)
 318 #endif
 319
 320 #endif /* __KERNEL__ */
 321 #endif /* __AUFS_BRANCH_H__ */