fs/aufs/file.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  * file operations
  20  */
  21
  22 #ifndef __AUFS_FILE_H__
  23 #define __AUFS_FILE_H__
  24
  25 #ifdef __KERNEL__
  26
  27 #include <linux/file.h>
  28 #include <linux/fs.h>
  29 #include <linux/mm_types.h>
  30 #include <linux/poll.h>
  31 #include "rwsem.h"
  32
  33 struct au_branch;
  34 struct au_hfile {
  35         struct file             *hf_file;
  36         struct au_branch        *hf_br;
  37 };
  38
  39 struct au_vdir;
  40 struct au_fidir {
  41         aufs_bindex_t           fd_bbot;
  42         aufs_bindex_t           fd_nent;
  43         struct au_vdir          *fd_vdir_cache;
  44         struct au_hfile         fd_hfile[];
  45 };
  46
  47 static inline int au_fidir_sz(int nent)
  48 {
  49         AuDebugOn(nent < 0);
  50         return sizeof(struct au_fidir) + sizeof(struct au_hfile) * nent;
  51 }
  52
  53 struct au_finfo {
  54         atomic_t                fi_generation;
  55
  56         struct au_rwsem         fi_rwsem;
  57         aufs_bindex_t           fi_btop;
  58
  59         /* do not union them */
  60         struct {                                /* for non-dir */
  61                 struct au_hfile                 fi_htop;
  62                 atomic_t                        fi_mmapped;
  63         };
  64         struct au_fidir         *fi_hdir;       /* for dir only */
  65
  66         struct hlist_node       fi_hlist;
  67         struct file             *fi_file;       /* very ugly */
  68 } ____cacheline_aligned_in_smp;
  69
  70 /* ---------------------------------------------------------------------- */
  71
  72 /* file.c */
  73 extern const struct address_space_operations aufs_aop;
  74 unsigned int au_file_roflags(unsigned int flags);
  75 struct file *au_h_open(struct dentry *dentry, aufs_bindex_t bindex, int flags,
  76                        struct file *file, int force_wr);
  77 struct au_do_open_args {
  78         int             aopen;
  79         int             (*open)(struct file *file, int flags,
  80                                 struct file *h_file);
  81         struct au_fidir *fidir;
  82         struct file     *h_file;
  83 };
  84 int au_do_open(struct file *file, struct au_do_open_args *args);
  85 int au_reopen_nondir(struct file *file);
  86 struct au_pin;
  87 int au_ready_to_write(struct file *file, loff_t len, struct au_pin *pin);
  88 int au_reval_and_lock_fdi(struct file *file, int (*reopen)(struct file *file),
  89                           int wlock, unsigned int fi_lsc);
  90 int au_do_flush(struct file *file, fl_owner_t id,
  91                 int (*flush)(struct file *file, fl_owner_t id));
  92
  93 /* poll.c */
  94 #ifdef CONFIG_AUFS_POLL
  95 unsigned int aufs_poll(struct file *file, poll_table *wait);
  96 #endif
  97
  98 #ifdef CONFIG_AUFS_BR_HFSPLUS
  99 /* hfsplus.c */
 100 struct file *au_h_open_pre(struct dentry *dentry, aufs_bindex_t bindex,
 101                            int force_wr);
 102 void au_h_open_post(struct dentry *dentry, aufs_bindex_t bindex,
 103                     struct file *h_file);
 104 #else
 105 AuStub(struct file *, au_h_open_pre, return NULL, struct dentry *dentry,
 106        aufs_bindex_t bindex, int force_wr)
 107 AuStubVoid(au_h_open_post, struct dentry *dentry, aufs_bindex_t bindex,
 108            struct file *h_file);
 109 #endif
 110
 111 /* f_op.c */
 112 extern const struct file_operations aufs_file_fop;
 113 int au_do_open_nondir(struct file *file, int flags, struct file *h_file);
 114 int aufs_release_nondir(struct inode *inode __maybe_unused, struct file *file);
 115 struct file *au_read_pre(struct file *file, int keep_fi, unsigned int lsc);
 116
 117 /* finfo.c */
 118 void au_hfput(struct au_hfile *hf, int execed);
 119 void au_set_h_fptr(struct file *file, aufs_bindex_t bindex,
 120                    struct file *h_file);
 121
 122 void au_update_figen(struct file *file);
 123 struct au_fidir *au_fidir_alloc(struct super_block *sb);
 124 int au_fidir_realloc(struct au_finfo *finfo, int nbr, int may_shrink);
 125
 126 void au_fi_init_once(void *_fi);
 127 void au_finfo_fin(struct file *file);
 128 int au_finfo_init(struct file *file, struct au_fidir *fidir);
 129
 130 /* ioctl.c */
 131 long aufs_ioctl_nondir(struct file *file, unsigned int cmd, unsigned long arg);
 132 #ifdef CONFIG_COMPAT
 133 long aufs_compat_ioctl_dir(struct file *file, unsigned int cmd,
 134                            unsigned long arg);
 135 long aufs_compat_ioctl_nondir(struct file *file, unsigned int cmd,
 136                               unsigned long arg);
 137 #endif
 138
 139 /* ---------------------------------------------------------------------- */
 140
 141 static inline struct au_finfo *au_fi(struct file *file)
 142 {
 143         return file->private_data;
 144 }
 145
 146 /* ---------------------------------------------------------------------- */
 147
 148 /*
 149  * fi_read_lock, fi_write_lock,
 150  * fi_read_unlock, fi_write_unlock, fi_downgrade_lock
 151  */
 152 AuSimpleRwsemFuncs(fi, struct file *f, &au_fi(f)->fi_rwsem);
 153
 154 /* lock subclass for finfo */
 155 enum {
 156         AuLsc_FI_1,
 157         AuLsc_FI_2
 158 };
 159
 160 static inline void fi_read_lock_nested(struct file *f, unsigned int lsc)
 161 {
 162         au_rw_read_lock_nested(&au_fi(f)->fi_rwsem, lsc);
 163 }
 164
 165 static inline void fi_write_lock_nested(struct file *f, unsigned int lsc)
 166 {
 167         au_rw_write_lock_nested(&au_fi(f)->fi_rwsem, lsc);
 168 }
 169
 170 /*
 171  * fi_read_lock_1, fi_write_lock_1,
 172  * fi_read_lock_2, fi_write_lock_2
 173  */
 174 #define AuReadLockFunc(name) \
 175 static inline void fi_read_lock_##name(struct file *f) \
 176 { fi_read_lock_nested(f, AuLsc_FI_##name); }
 177
 178 #define AuWriteLockFunc(name) \
 179 static inline void fi_write_lock_##name(struct file *f) \
 180 { fi_write_lock_nested(f, AuLsc_FI_##name); }
 181
 182 #define AuRWLockFuncs(name) \
 183         AuReadLockFunc(name) \
 184         AuWriteLockFunc(name)
 185
 186 AuRWLockFuncs(1);
 187 AuRWLockFuncs(2);
 188
 189 #undef AuReadLockFunc
 190 #undef AuWriteLockFunc
 191 #undef AuRWLockFuncs
 192
 193 #define FiMustNoWaiters(f)      AuRwMustNoWaiters(&au_fi(f)->fi_rwsem)
 194 #define FiMustAnyLock(f)        AuRwMustAnyLock(&au_fi(f)->fi_rwsem)
 195 #define FiMustWriteLock(f)      AuRwMustWriteLock(&au_fi(f)->fi_rwsem)
 196
 197 /* ---------------------------------------------------------------------- */
 198
 199 /* todo: hard/soft set? */
 200 static inline aufs_bindex_t au_fbtop(struct file *file)
 201 {
 202         FiMustAnyLock(file);
 203         return au_fi(file)->fi_btop;
 204 }
 205
 206 static inline aufs_bindex_t au_fbbot_dir(struct file *file)
 207 {
 208         FiMustAnyLock(file);
 209         AuDebugOn(!au_fi(file)->fi_hdir);
 210         return au_fi(file)->fi_hdir->fd_bbot;
 211 }
 212
 213 static inline struct au_vdir *au_fvdir_cache(struct file *file)
 214 {
 215         FiMustAnyLock(file);
 216         AuDebugOn(!au_fi(file)->fi_hdir);
 217         return au_fi(file)->fi_hdir->fd_vdir_cache;
 218 }
 219
 220 static inline void au_set_fbtop(struct file *file, aufs_bindex_t bindex)
 221 {
 222         FiMustWriteLock(file);
 223         au_fi(file)->fi_btop = bindex;
 224 }
 225
 226 static inline void au_set_fbbot_dir(struct file *file, aufs_bindex_t bindex)
 227 {
 228         FiMustWriteLock(file);
 229         AuDebugOn(!au_fi(file)->fi_hdir);
 230         au_fi(file)->fi_hdir->fd_bbot = bindex;
 231 }
 232
 233 static inline void au_set_fvdir_cache(struct file *file,
 234                                       struct au_vdir *vdir_cache)
 235 {
 236         FiMustWriteLock(file);
 237         AuDebugOn(!au_fi(file)->fi_hdir);
 238         au_fi(file)->fi_hdir->fd_vdir_cache = vdir_cache;
 239 }
 240
 241 static inline struct file *au_hf_top(struct file *file)
 242 {
 243         FiMustAnyLock(file);
 244         AuDebugOn(au_fi(file)->fi_hdir);
 245         return au_fi(file)->fi_htop.hf_file;
 246 }
 247
 248 static inline struct file *au_hf_dir(struct file *file, aufs_bindex_t bindex)
 249 {
 250         FiMustAnyLock(file);
 251         AuDebugOn(!au_fi(file)->fi_hdir);
 252         return au_fi(file)->fi_hdir->fd_hfile[0 + bindex].hf_file;
 253 }
 254
 255 /* todo: memory barrier? */
 256 static inline unsigned int au_figen(struct file *f)
 257 {
 258         return atomic_read(&au_fi(f)->fi_generation);
 259 }
 260
 261 static inline void au_set_mmapped(struct file *f)
 262 {
 263         if (atomic_inc_return(&au_fi(f)->fi_mmapped))
 264                 return;
 265         pr_warn("fi_mmapped wrapped around\n");
 266         while (!atomic_inc_return(&au_fi(f)->fi_mmapped))
 267                 ;
 268 }
 269
 270 static inline void au_unset_mmapped(struct file *f)
 271 {
 272         atomic_dec(&au_fi(f)->fi_mmapped);
 273 }
 274
 275 static inline int au_test_mmapped(struct file *f)
 276 {
 277         return atomic_read(&au_fi(f)->fi_mmapped);
 278 }
 279
 280 /* customize vma->vm_file */
 281
 282 static inline void au_do_vm_file_reset(struct vm_area_struct *vma,
 283                                        struct file *file)
 284 {
 285         struct file *f;
 286
 287         f = vma->vm_file;
 288         get_file(file);
 289         vma->vm_file = file;
 290         fput(f);
 291 }
 292
 293 #ifdef CONFIG_MMU
 294 #define AuDbgVmRegion(file, vma) do {} while (0)
 295
 296 static inline void au_vm_file_reset(struct vm_area_struct *vma,
 297                                     struct file *file)
 298 {
 299         au_do_vm_file_reset(vma, file);
 300 }
 301 #else
 302 #define AuDbgVmRegion(file, vma) \
 303         AuDebugOn((vma)->vm_region && (vma)->vm_region->vm_file != (file))
 304
 305 static inline void au_vm_file_reset(struct vm_area_struct *vma,
 306                                     struct file *file)
 307 {
 308         struct file *f;
 309
 310         au_do_vm_file_reset(vma, file);
 311         f = vma->vm_region->vm_file;
 312         get_file(file);
 313         vma->vm_region->vm_file = file;
 314         fput(f);
 315 }
 316 #endif /* CONFIG_MMU */
 317
 318 /* handle vma->vm_prfile */
 319 static inline void au_vm_prfile_set(struct vm_area_struct *vma,
 320                                     struct file *file)
 321 {
 322         get_file(file);
 323         vma->vm_prfile = file;
 324 #ifndef CONFIG_MMU
 325         get_file(file);
 326         vma->vm_region->vm_prfile = file;
 327 #endif
 328 }
 329
 330 #endif /* __KERNEL__ */
 331 #endif /* __AUFS_FILE_H__ */