fs/aufs/dentry.h

   1 /*
   2  * Copyright (C) 2005-2011 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, write to the Free Software
  16  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  17  */
  18
  19 /*
  20  * lookup and dentry operations
  21  */
  22
  23 #ifndef __AUFS_DENTRY_H__
  24 #define __AUFS_DENTRY_H__
  25
  26 #ifdef __KERNEL__
  27
  28 #include <linux/dcache.h>
  29 #include <linux/aufs_type.h>
  30 #include "rwsem.h"
  31
  32 struct au_hdentry {
  33         struct dentry           *hd_dentry;
  34         aufs_bindex_t           hd_id;
  35 };
  36
  37 struct au_dinfo {
  38         atomic_t                di_generation;
  39
  40         struct au_rwsem         di_rwsem;
  41         aufs_bindex_t           di_bstart, di_bend, di_bwh, di_bdiropq;
  42         struct au_hdentry       *di_hdentry;
  43 } ____cacheline_aligned_in_smp;
  44
  45 /* ---------------------------------------------------------------------- */
  46
  47 /* dentry.c */
  48 extern const struct dentry_operations aufs_dop;
  49 struct au_branch;
  50 struct dentry *au_lkup_one(struct qstr *name, struct dentry *h_parent,
  51                            struct au_branch *br, struct nameidata *nd);
  52 struct dentry *au_sio_lkup_one(struct qstr *name, struct dentry *parent,
  53                                struct au_branch *br);
  54 int au_h_verify(struct dentry *h_dentry, unsigned int udba, struct inode *h_dir,
  55                 struct dentry *h_parent, struct au_branch *br);
  56
  57 int au_lkup_dentry(struct dentry *dentry, aufs_bindex_t bstart, mode_t type,
  58                    struct nameidata *nd);
  59 int au_lkup_neg(struct dentry *dentry, aufs_bindex_t bindex);
  60 int au_refresh_dentry(struct dentry *dentry, struct dentry *parent);
  61 int au_reval_dpath(struct dentry *dentry, unsigned int sigen);
  62
  63 /* dinfo.c */
  64 void au_di_init_once(void *_di);
  65 struct au_dinfo *au_di_alloc(struct super_block *sb, unsigned int lsc);
  66 void au_di_free(struct au_dinfo *dinfo);
  67 void au_di_swap(struct au_dinfo *a, struct au_dinfo *b);
  68 void au_di_cp(struct au_dinfo *dst, struct au_dinfo *src);
  69 int au_di_init(struct dentry *dentry);
  70 void au_di_fin(struct dentry *dentry);
  71 int au_di_realloc(struct au_dinfo *dinfo, int nbr);
  72
  73 void di_read_lock(struct dentry *d, int flags, unsigned int lsc);
  74 void di_read_unlock(struct dentry *d, int flags);
  75 void di_downgrade_lock(struct dentry *d, int flags);
  76 void di_write_lock(struct dentry *d, unsigned int lsc);
  77 void di_write_unlock(struct dentry *d);
  78 void di_write_lock2_child(struct dentry *d1, struct dentry *d2, int isdir);
  79 void di_write_lock2_parent(struct dentry *d1, struct dentry *d2, int isdir);
  80 void di_write_unlock2(struct dentry *d1, struct dentry *d2);
  81
  82 struct dentry *au_h_dptr(struct dentry *dentry, aufs_bindex_t bindex);
  83 struct dentry *au_h_d_alias(struct dentry *dentry, aufs_bindex_t bindex);
  84 aufs_bindex_t au_dbtail(struct dentry *dentry);
  85 aufs_bindex_t au_dbtaildir(struct dentry *dentry);
  86
  87 void au_set_h_dptr(struct dentry *dentry, aufs_bindex_t bindex,
  88                    struct dentry *h_dentry);
  89 int au_digen_test(struct dentry *dentry, unsigned int sigen);
  90 int au_dbrange_test(struct dentry *dentry);
  91 void au_update_digen(struct dentry *dentry);
  92 void au_update_dbrange(struct dentry *dentry, int do_put_zero);
  93 void au_update_dbstart(struct dentry *dentry);
  94 void au_update_dbend(struct dentry *dentry);
  95 int au_find_dbindex(struct dentry *dentry, struct dentry *h_dentry);
  96
  97 /* ---------------------------------------------------------------------- */
  98
  99 static inline struct au_dinfo *au_di(struct dentry *dentry)
 100 {
 101         return dentry->d_fsdata;
 102 }
 103
 104 /* ---------------------------------------------------------------------- */
 105
 106 /* lock subclass for dinfo */
 107 enum {
 108         AuLsc_DI_CHILD,         /* child first */
 109         AuLsc_DI_CHILD2,        /* rename(2), link(2), and cpup at hnotify */
 110         AuLsc_DI_CHILD3,        /* copyup dirs */
 111         AuLsc_DI_PARENT,
 112         AuLsc_DI_PARENT2,
 113         AuLsc_DI_PARENT3,
 114         AuLsc_DI_TMP            /* temp for replacing dinfo */
 115 };
 116
 117 /*
 118  * di_read_lock_child, di_write_lock_child,
 119  * di_read_lock_child2, di_write_lock_child2,
 120  * di_read_lock_child3, di_write_lock_child3,
 121  * di_read_lock_parent, di_write_lock_parent,
 122  * di_read_lock_parent2, di_write_lock_parent2,
 123  * di_read_lock_parent3, di_write_lock_parent3,
 124  */
 125 #define AuReadLockFunc(name, lsc) \
 126 static inline void di_read_lock_##name(struct dentry *d, int flags) \
 127 { di_read_lock(d, flags, AuLsc_DI_##lsc); }
 128
 129 #define AuWriteLockFunc(name, lsc) \
 130 static inline void di_write_lock_##name(struct dentry *d) \
 131 { di_write_lock(d, AuLsc_DI_##lsc); }
 132
 133 #define AuRWLockFuncs(name, lsc) \
 134         AuReadLockFunc(name, lsc) \
 135         AuWriteLockFunc(name, lsc)
 136
 137 AuRWLockFuncs(child, CHILD);
 138 AuRWLockFuncs(child2, CHILD2);
 139 AuRWLockFuncs(child3, CHILD3);
 140 AuRWLockFuncs(parent, PARENT);
 141 AuRWLockFuncs(parent2, PARENT2);
 142 AuRWLockFuncs(parent3, PARENT3);
 143
 144 #undef AuReadLockFunc
 145 #undef AuWriteLockFunc
 146 #undef AuRWLockFuncs
 147
 148 #define DiMustNoWaiters(d)      AuRwMustNoWaiters(&au_di(d)->di_rwsem)
 149 #define DiMustAnyLock(d)        AuRwMustAnyLock(&au_di(d)->di_rwsem)
 150 #define DiMustWriteLock(d)      AuRwMustWriteLock(&au_di(d)->di_rwsem)
 151
 152 /* ---------------------------------------------------------------------- */
 153
 154 /* todo: memory barrier? */
 155 static inline unsigned int au_digen(struct dentry *d)
 156 {
 157         return atomic_read(&au_di(d)->di_generation);
 158 }
 159
 160 static inline void au_h_dentry_init(struct au_hdentry *hdentry)
 161 {
 162         hdentry->hd_dentry = NULL;
 163 }
 164
 165 static inline void au_hdput(struct au_hdentry *hd)
 166 {
 167         if (hd)
 168                 dput(hd->hd_dentry);
 169 }
 170
 171 static inline aufs_bindex_t au_dbstart(struct dentry *dentry)
 172 {
 173         DiMustAnyLock(dentry);
 174         return au_di(dentry)->di_bstart;
 175 }
 176
 177 static inline aufs_bindex_t au_dbend(struct dentry *dentry)
 178 {
 179         DiMustAnyLock(dentry);
 180         return au_di(dentry)->di_bend;
 181 }
 182
 183 static inline aufs_bindex_t au_dbwh(struct dentry *dentry)
 184 {
 185         DiMustAnyLock(dentry);
 186         return au_di(dentry)->di_bwh;
 187 }
 188
 189 static inline aufs_bindex_t au_dbdiropq(struct dentry *dentry)
 190 {
 191         DiMustAnyLock(dentry);
 192         return au_di(dentry)->di_bdiropq;
 193 }
 194
 195 /* todo: hard/soft set? */
 196 static inline void au_set_dbstart(struct dentry *dentry, aufs_bindex_t bindex)
 197 {
 198         DiMustWriteLock(dentry);
 199         au_di(dentry)->di_bstart = bindex;
 200 }
 201
 202 static inline void au_set_dbend(struct dentry *dentry, aufs_bindex_t bindex)
 203 {
 204         DiMustWriteLock(dentry);
 205         au_di(dentry)->di_bend = bindex;
 206 }
 207
 208 static inline void au_set_dbwh(struct dentry *dentry, aufs_bindex_t bindex)
 209 {
 210         DiMustWriteLock(dentry);
 211         /* dbwh can be outside of bstart - bend range */
 212         au_di(dentry)->di_bwh = bindex;
 213 }
 214
 215 static inline void au_set_dbdiropq(struct dentry *dentry, aufs_bindex_t bindex)
 216 {
 217         DiMustWriteLock(dentry);
 218         au_di(dentry)->di_bdiropq = bindex;
 219 }
 220
 221 /* ---------------------------------------------------------------------- */
 222
 223 #ifdef CONFIG_AUFS_HNOTIFY
 224 static inline void au_digen_dec(struct dentry *d)
 225 {
 226         atomic_dec(&au_di(d)->di_generation);
 227 }
 228
 229 static inline void au_hn_di_reinit(struct dentry *dentry)
 230 {
 231         dentry->d_fsdata = NULL;
 232 }
 233 #else
 234 AuStubVoid(au_hn_di_reinit, struct dentry *dentry __maybe_unused)
 235 #endif /* CONFIG_AUFS_HNOTIFY */
 236
 237 #endif /* __KERNEL__ */
 238 #endif /* __AUFS_DENTRY_H__ */