mount.h 4.1 KB

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  1. /*
  2. *
  3. * Definitions for mount interface. This describes the in the kernel build
  4. * linkedlist with mounted filesystems.
  5. *
  6. * Author: Marco van Wieringen <mvw@planets.elm.net>
  7. *
  8. */
  9. #ifndef _LINUX_MOUNT_H
  10. #define _LINUX_MOUNT_H
  11. #include <linux/types.h>
  12. #include <linux/list.h>
  13. #include <linux/nodemask.h>
  14. #include <linux/spinlock.h>
  15. #include <asm/atomic.h>
  16. struct super_block;
  17. struct vfsmount;
  18. struct dentry;
  19. struct mnt_namespace;
  20. #define MNT_NOSUID 0x01
  21. #define MNT_NODEV 0x02
  22. #define MNT_NOEXEC 0x04
  23. #define MNT_NOATIME 0x08
  24. #define MNT_NODIRATIME 0x10
  25. #define MNT_RELATIME 0x20
  26. #define MNT_READONLY 0x40 /* does the user want this to be r/o? */
  27. #define MNT_SHRINKABLE 0x100
  28. #define MNT_WRITE_HOLD 0x200
  29. #define MNT_SHARED 0x1000 /* if the vfsmount is a shared mount */
  30. #define MNT_UNBINDABLE 0x2000 /* if the vfsmount is a unbindable mount */
  31. /*
  32. * MNT_SHARED_MASK is the set of flags that should be cleared when a
  33. * mount becomes shared. Currently, this is only the flag that says a
  34. * mount cannot be bind mounted, since this is how we create a mount
  35. * that shares events with another mount. If you add a new MNT_*
  36. * flag, consider how it interacts with shared mounts.
  37. */
  38. #define MNT_SHARED_MASK (MNT_UNBINDABLE)
  39. #define MNT_PROPAGATION_MASK (MNT_SHARED | MNT_UNBINDABLE)
  40. #define MNT_INTERNAL 0x4000
  41. struct vfsmount {
  42. struct list_head mnt_hash;
  43. struct vfsmount *mnt_parent; /* fs we are mounted on */
  44. struct dentry *mnt_mountpoint; /* dentry of mountpoint */
  45. struct dentry *mnt_root; /* root of the mounted tree */
  46. struct super_block *mnt_sb; /* pointer to superblock */
  47. struct list_head mnt_mounts; /* list of children, anchored here */
  48. struct list_head mnt_child; /* and going through their mnt_child */
  49. int mnt_flags;
  50. /* 4 bytes hole on 64bits arches without fsnotify */
  51. #ifdef CONFIG_FSNOTIFY
  52. __u32 mnt_fsnotify_mask;
  53. struct hlist_head mnt_fsnotify_marks;
  54. #endif
  55. const char *mnt_devname; /* Name of device e.g. /dev/dsk/hda1 */
  56. struct list_head mnt_list;
  57. struct list_head mnt_expire; /* link in fs-specific expiry list */
  58. struct list_head mnt_share; /* circular list of shared mounts */
  59. struct list_head mnt_slave_list;/* list of slave mounts */
  60. struct list_head mnt_slave; /* slave list entry */
  61. struct vfsmount *mnt_master; /* slave is on master->mnt_slave_list */
  62. struct mnt_namespace *mnt_ns; /* containing namespace */
  63. int mnt_id; /* mount identifier */
  64. int mnt_group_id; /* peer group identifier */
  65. /*
  66. * We put mnt_count & mnt_expiry_mark at the end of struct vfsmount
  67. * to let these frequently modified fields in a separate cache line
  68. * (so that reads of mnt_flags wont ping-pong on SMP machines)
  69. */
  70. atomic_t mnt_count;
  71. int mnt_expiry_mark; /* true if marked for expiry */
  72. int mnt_pinned;
  73. int mnt_ghosts;
  74. #ifdef CONFIG_SMP
  75. int __percpu *mnt_writers;
  76. #else
  77. int mnt_writers;
  78. #endif
  79. };
  80. static inline int *get_mnt_writers_ptr(struct vfsmount *mnt)
  81. {
  82. #ifdef CONFIG_SMP
  83. return mnt->mnt_writers;
  84. #else
  85. return &mnt->mnt_writers;
  86. #endif
  87. }
  88. static inline struct vfsmount *mntget(struct vfsmount *mnt)
  89. {
  90. if (mnt)
  91. atomic_inc(&mnt->mnt_count);
  92. return mnt;
  93. }
  94. struct file; /* forward dec */
  95. extern int mnt_want_write(struct vfsmount *mnt);
  96. extern int mnt_want_write_file(struct file *file);
  97. extern int mnt_clone_write(struct vfsmount *mnt);
  98. extern void mnt_drop_write(struct vfsmount *mnt);
  99. extern void mntput_no_expire(struct vfsmount *mnt);
  100. extern void mnt_pin(struct vfsmount *mnt);
  101. extern void mnt_unpin(struct vfsmount *mnt);
  102. extern int __mnt_is_readonly(struct vfsmount *mnt);
  103. static inline void mntput(struct vfsmount *mnt)
  104. {
  105. if (mnt) {
  106. mnt->mnt_expiry_mark = 0;
  107. mntput_no_expire(mnt);
  108. }
  109. }
  110. extern struct vfsmount *do_kern_mount(const char *fstype, int flags,
  111. const char *name, void *data);
  112. struct file_system_type;
  113. extern struct vfsmount *vfs_kern_mount(struct file_system_type *type,
  114. int flags, const char *name,
  115. void *data);
  116. struct nameidata;
  117. struct path;
  118. extern int do_add_mount(struct vfsmount *newmnt, struct path *path,
  119. int mnt_flags, struct list_head *fslist);
  120. extern void mark_mounts_for_expiry(struct list_head *mounts);
  121. extern dev_t name_to_dev_t(char *name);
  122. #endif /* _LINUX_MOUNT_H */