include/linux/fs_struct.h

   1 #ifndef _LINUX_FS_STRUCT_H
   2 #define _LINUX_FS_STRUCT_H
   3 #ifdef __KERNEL__
   4
   5 struct fs_struct {
   6         atomic_t count;
   7         rwlock_t lock;
   8         int umask;
   9         struct dentry * root, * pwd, * altroot;
  10         struct vfsmount * rootmnt, * pwdmnt, * altrootmnt;
  11 };
  12
  13 #define INIT_FS { \
  14         ATOMIC_INIT(1), \
  15         RW_LOCK_UNLOCKED, \
  16         0022, \
  17         NULL, NULL, NULL, NULL, NULL, NULL \
  18 }
  19
  20 extern void exit_fs(struct task_struct *);
  21 extern void set_fs_altroot(void);
  22
  23 /*
  24  * Replace the fs->{rootmnt,root} with {mnt,dentry}. Put the old values.
  25  * It can block. Requires the big lock held.
  26  */
  27
  28 static inline void set_fs_root(struct fs_struct *fs,
  29         struct vfsmount *mnt,
  30         struct dentry *dentry)
  31 {
  32         struct dentry *old_root;
  33         struct vfsmount *old_rootmnt;
  34         write_lock(&fs->lock);
  35         old_root = fs->root;
  36         old_rootmnt = fs->rootmnt;
  37         fs->rootmnt = mntget(mnt);
  38         fs->root = dget(dentry);
  39         write_unlock(&fs->lock);
  40         if (old_root) {
  41                 dput(old_root);
  42                 mntput(old_rootmnt);
  43         }
  44 }
  45
  46 /*
  47  * Replace the fs->{pwdmnt,pwd} with {mnt,dentry}. Put the old values.
  48  * It can block. Requires the big lock held.
  49  */
  50
  51 static inline void set_fs_pwd(struct fs_struct *fs,
  52         struct vfsmount *mnt,
  53         struct dentry *dentry)
  54 {
  55         struct dentry *old_pwd;
  56         struct vfsmount *old_pwdmnt;
  57         write_lock(&fs->lock);
  58         old_pwd = fs->pwd;
  59         old_pwdmnt = fs->pwdmnt;
  60         fs->pwdmnt = mntget(mnt);
  61         fs->pwd = dget(dentry);
  62         write_unlock(&fs->lock);
  63         if (old_pwd) {
  64                 dput(old_pwd);
  65                 mntput(old_pwdmnt);
  66         }
  67 }
  68
  69 struct fs_struct *copy_fs_struct(struct fs_struct *old);
  70 void put_fs_struct(struct fs_struct *fs);
  71
  72 #endif
  73 #endif