fs/aufs/file.h

   1 /*
   2  * Copyright (C) 2005-2016 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/poll.h>
  30 #include "rwsem.h"
  31
  32 struct au_branch;
  33 struct au_hfile {
  34         struct file             *hf_file;
  35         struct au_branch        *hf_br;
  36 };
  37
  38 struct au_vdir;
  39 struct au_fidir {
  40         aufs_bindex_t           fd_bbot;
  41         aufs_bindex_t           fd_nent;
  42         struct au_vdir          *fd_vdir_cache;
  43         struct au_hfile         fd_hfile[];
  44 };
  45
  46 static inline int au_fidir_sz(int nent)
  47 {
  48         AuDebugOn(nent < 0);
  49         return sizeof(struct au_fidir) + sizeof(struct au_hfile) * nent;
  50 }
  51
  52 struct au_finfo {
  53         atomic_t                fi_generation;
  54
  55         struct au_rwsem         fi_rwsem;
  56         aufs_bindex_t           fi_btop;
  57
  58         /* do not union them */
  59         struct {                                /* for non-dir */
  60                 struct au_hfile                 fi_htop;
  61                 atomic_t                        fi_mmapped;
  62         };
  63         struct au_fidir         *fi_hdir;       /* for dir only */
  64
  65         struct hlist_node       fi_hlist;
  66         union {
  67                 struct file             *fi_file;       /* very ugly */
  68                 struct llist_node       fi_lnode;       /* delayed free */
  69         };
  70 } ____cacheline_aligned_in_smp;
  71
  72 /* ---------------------------------------------------------------------- */
  73
  74 /* file.c */
  75 extern const struct address_space_operations aufs_aop;
  76 unsigned int au_file_roflags(unsigned int flags);
  77 struct file *au_h_open(struct dentry *dentry, aufs_bindex_t bindex, int flags,
  78                        struct file *file, int force_wr);
  79 struct au_do_open_args {
  80         int             no_lock;
  81         int             (*open)(struct file *file, int flags,
  82                                 struct file *h_file);
  83         struct au_fidir *fidir;
  84         struct file     *h_file;
  85 };
  86 int au_do_open(struct file *file, struct au_do_open_args *args);
  87 int au_reopen_nondir(struct file *file);
  88 struct au_pin;
  89 int au_ready_to_write(struct file *file, loff_t len, struct au_pin *pin);
  90 int au_reval_and_lock_fdi(struct file *file, int (*reopen)(struct file *file),
  91                           int wlock);
  92 int au_do_flush(struct file *file, fl_owner_t id,
  93                 int (*flush)(struct file *file, fl_owner_t id));
  94
  95 /* poll.c */
  96 #ifdef CONFIG_AUFS_POLL
  97 unsigned int aufs_poll(struct file *file, poll_table *wait);
  98 #endif
  99
 100 #ifdef CONFIG_AUFS_BR_HFSPLUS
 101 /* hfsplus.c */
 102 struct file *au_h_open_pre(struct dentry *dentry, aufs_bindex_t bindex,
 103                            int force_wr);
 104 void au_h_open_post(struct dentry *dentry, aufs_bindex_t bindex,
 105                     struct file *h_file);
 106 #else
 107 AuStub(struct file *, au_h_open_pre, return NULL, struct dentry *dentry,
 108        aufs_bindex_t bindex, int force_wr)
 109 AuStubVoid(au_h_open_post, struct dentry *dentry, aufs_bindex_t bindex,
 110            struct file *h_file);
 111 #endif
 112
 113 /* f_op.c */
 114 extern const struct file_operations aufs_file_fop;
 115 int au_do_open_nondir(struct file *file, int flags, struct file *h_file);
 116 int aufs_release_nondir(struct inode *inode __maybe_unused, struct file *file);
 117 struct file *au_read_pre(struct file *file, int keep_fi);
 118
 119 /* finfo.c */
 120 void au_hfput(struct au_hfile *hf, int execed);
 121 void au_set_h_fptr(struct file *file, aufs_bindex_t bindex,
 122                    struct file *h_file);
 123
 124 void au_update_figen(struct file *file);
 125 struct au_fidir *au_fidir_alloc(struct super_block *sb);
 126 int au_fidir_realloc(struct au_finfo *finfo, int nbr, int may_shrink);
 127
 128 void au_fi_init_once(void *_fi);
 129 void au_finfo_fin(struct file *file, int atonce);
 130 int au_finfo_init(struct file *file, struct au_fidir *fidir);
 131
 132 /* ioctl.c */
 133 long aufs_ioctl_nondir(struct file *file, unsigned int cmd, unsigned long arg);
 134 #ifdef CONFIG_COMPAT
 135 long aufs_compat_ioctl_dir(struct file *file, unsigned int cmd,
 136                            unsigned long arg);
 137 long aufs_compat_ioctl_nondir(struct file *file, unsigned int cmd,
 138                               unsigned long arg);
 139 #endif
 140
 141 /* ---------------------------------------------------------------------- */
 142
 143 static inline struct au_finfo *au_fi(struct file *file)
 144 {
 145         return file->private_data;
 146 }
 147
 148 /* ---------------------------------------------------------------------- */
 149
 150 /*
 151  * fi_read_lock, fi_write_lock,
 152  * fi_read_unlock, fi_write_unlock, fi_downgrade_lock
 153  */
 154 AuSimpleRwsemFuncs(fi, struct file *f, &au_fi(f)->fi_rwsem);
 155
 156 #define FiMustNoWaiters(f)      AuRwMustNoWaiters(&au_fi(f)->fi_rwsem)
 157 #define FiMustAnyLock(f)        AuRwMustAnyLock(&au_fi(f)->fi_rwsem)
 158 #define FiMustWriteLock(f)      AuRwMustWriteLock(&au_fi(f)->fi_rwsem)
 159
 160 /* ---------------------------------------------------------------------- */
 161
 162 /* todo: hard/soft set? */
 163 static inline aufs_bindex_t au_fbtop(struct file *file)
 164 {
 165         FiMustAnyLock(file);
 166         return au_fi(file)->fi_btop;
 167 }
 168
 169 static inline aufs_bindex_t au_fbbot_dir(struct file *file)
 170 {
 171         FiMustAnyLock(file);
 172         AuDebugOn(!au_fi(file)->fi_hdir);
 173         return au_fi(file)->fi_hdir->fd_bbot;
 174 }
 175
 176 static inline struct au_vdir *au_fvdir_cache(struct file *file)
 177 {
 178         FiMustAnyLock(file);
 179         AuDebugOn(!au_fi(file)->fi_hdir);
 180         return au_fi(file)->fi_hdir->fd_vdir_cache;
 181 }
 182
 183 static inline void au_set_fbtop(struct file *file, aufs_bindex_t bindex)
 184 {
 185         FiMustWriteLock(file);
 186         au_fi(file)->fi_btop = bindex;
 187 }
 188
 189 static inline void au_set_fbbot_dir(struct file *file, aufs_bindex_t bindex)
 190 {
 191         FiMustWriteLock(file);
 192         AuDebugOn(!au_fi(file)->fi_hdir);
 193         au_fi(file)->fi_hdir->fd_bbot = bindex;
 194 }
 195
 196 static inline void au_set_fvdir_cache(struct file *file,
 197                                       struct au_vdir *vdir_cache)
 198 {
 199         FiMustWriteLock(file);
 200         AuDebugOn(!au_fi(file)->fi_hdir);
 201         au_fi(file)->fi_hdir->fd_vdir_cache = vdir_cache;
 202 }
 203
 204 static inline struct file *au_hf_top(struct file *file)
 205 {
 206         FiMustAnyLock(file);
 207         AuDebugOn(au_fi(file)->fi_hdir);
 208         return au_fi(file)->fi_htop.hf_file;
 209 }
 210
 211 static inline struct file *au_hf_dir(struct file *file, aufs_bindex_t bindex)
 212 {
 213         FiMustAnyLock(file);
 214         AuDebugOn(!au_fi(file)->fi_hdir);
 215         return au_fi(file)->fi_hdir->fd_hfile[0 + bindex].hf_file;
 216 }
 217
 218 /* todo: memory barrier? */
 219 static inline unsigned int au_figen(struct file *f)
 220 {
 221         return atomic_read(&au_fi(f)->fi_generation);
 222 }
 223
 224 static inline void au_set_mmapped(struct file *f)
 225 {
 226         if (atomic_inc_return(&au_fi(f)->fi_mmapped))
 227                 return;
 228         pr_warn("fi_mmapped wrapped around\n");
 229         while (!atomic_inc_return(&au_fi(f)->fi_mmapped))
 230                 ;
 231 }
 232
 233 static inline void au_unset_mmapped(struct file *f)
 234 {
 235         atomic_dec(&au_fi(f)->fi_mmapped);
 236 }
 237
 238 static inline int au_test_mmapped(struct file *f)
 239 {
 240         return atomic_read(&au_fi(f)->fi_mmapped);
 241 }
 242
 243 /* customize vma->vm_file */
 244
 245 static inline void au_do_vm_file_reset(struct vm_area_struct *vma,
 246                                        struct file *file)
 247 {
 248         struct file *f;
 249
 250         f = vma->vm_file;
 251         get_file(file);
 252         vma->vm_file = file;
 253         fput(f);
 254 }
 255
 256 #ifdef CONFIG_MMU
 257 #define AuDbgVmRegion(file, vma) do {} while (0)
 258
 259 static inline void au_vm_file_reset(struct vm_area_struct *vma,
 260                                     struct file *file)
 261 {
 262         au_do_vm_file_reset(vma, file);
 263 }
 264 #else
 265 #define AuDbgVmRegion(file, vma) \
 266         AuDebugOn((vma)->vm_region && (vma)->vm_region->vm_file != (file))
 267
 268 static inline void au_vm_file_reset(struct vm_area_struct *vma,
 269                                     struct file *file)
 270 {
 271         struct file *f;
 272
 273         au_do_vm_file_reset(vma, file);
 274         f = vma->vm_region->vm_file;
 275         get_file(file);
 276         vma->vm_region->vm_file = file;
 277         fput(f);
 278 }
 279 #endif /* CONFIG_MMU */
 280
 281 /* handle vma->vm_prfile */
 282 static inline void au_vm_prfile_set(struct vm_area_struct *vma,
 283                                     struct file *file)
 284 {
 285         get_file(file);
 286         vma->vm_prfile = file;
 287 #ifndef CONFIG_MMU
 288         get_file(file);
 289         vma->vm_region->vm_prfile = file;
 290 #endif
 291 }
 292
 293 #endif /* __KERNEL__ */
 294 #endif /* __AUFS_FILE_H__ */