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 <[email protected]> 7 * 8 */ 9 #ifndef _LINUX_MOUNT_H 10 #define _LINUX_MOUNT_H 11 12 #include <linux/types.h> 13 #include <linux/list.h> 14 #include <linux/nodemask.h> 15 #include <linux/spinlock.h> 16 #include <asm/atomic.h> 17 18 struct super_block; 19 struct vfsmount; 20 struct dentry; 21 struct mnt_namespace; 22 23 #define MNT_NOSUID 0x01 24 #define MNT_NODEV 0x02 25 #define MNT_NOEXEC 0x04 26 #define MNT_NOATIME 0x08 27 #define MNT_NODIRATIME 0x10 28 #define MNT_RELATIME 0x20 29 #define MNT_READONLY 0x40 /* does the user want this to be r/o? */ 30 31 #define MNT_SHRINKABLE 0x100 32 #define MNT_WRITE_HOLD 0x200 33 34 #define MNT_SHARED 0x1000 /* if the vfsmount is a shared mount */ 35 #define MNT_UNBINDABLE 0x2000 /* if the vfsmount is a unbindable mount */ 36 /* 37 * MNT_SHARED_MASK is the set of flags that should be cleared when a 38 * mount becomes shared. Currently, this is only the flag that says a 39 * mount cannot be bind mounted, since this is how we create a mount 40 * that shares events with another mount. If you add a new MNT_* 41 * flag, consider how it interacts with shared mounts. 42 */ 43 #define MNT_SHARED_MASK (MNT_UNBINDABLE) 44 #define MNT_PROPAGATION_MASK (MNT_SHARED | MNT_UNBINDABLE) 45 46 47 #define MNT_INTERNAL 0x4000 48 49 struct vfsmount { 50 struct list_head mnt_hash; 51 struct vfsmount *mnt_parent; /* fs we are mounted on */ 52 struct dentry *mnt_mountpoint; /* dentry of mountpoint */ 53 struct dentry *mnt_root; /* root of the mounted tree */ 54 struct super_block *mnt_sb; /* pointer to superblock */ 55 struct list_head mnt_mounts; /* list of children, anchored here */ 56 struct list_head mnt_child; /* and going through their mnt_child */ 57 int mnt_flags; 58 /* 4 bytes hole on 64bits arches without fsnotify */ 59 #ifdef CONFIG_FSNOTIFY 60 __u32 mnt_fsnotify_mask; 61 struct hlist_head mnt_fsnotify_marks; 62 #endif 63 const char *mnt_devname; /* Name of device e.g. /dev/dsk/hda1 */ 64 struct list_head mnt_list; 65 struct list_head mnt_expire; /* link in fs-specific expiry list */ 66 struct list_head mnt_share; /* circular list of shared mounts */ 67 struct list_head mnt_slave_list;/* list of slave mounts */ 68 struct list_head mnt_slave; /* slave list entry */ 69 struct vfsmount *mnt_master; /* slave is on master->mnt_slave_list */ 70 struct mnt_namespace *mnt_ns; /* containing namespace */ 71 int mnt_id; /* mount identifier */ 72 int mnt_group_id; /* peer group identifier */ 73 /* 74 * We put mnt_count & mnt_expiry_mark at the end of struct vfsmount 75 * to let these frequently modified fields in a separate cache line 76 * (so that reads of mnt_flags wont ping-pong on SMP machines) 77 */ 78 atomic_t mnt_count; 79 int mnt_expiry_mark; /* true if marked for expiry */ 80 int mnt_pinned; 81 int mnt_ghosts; 82 #ifdef CONFIG_SMP 83 int __percpu *mnt_writers; 84 #else 85 int mnt_writers; 86 #endif 87 }; 88 89 static inline int *get_mnt_writers_ptr(struct vfsmount *mnt) 90 { 91 #ifdef CONFIG_SMP 92 return mnt->mnt_writers; 93 #else 94 return &mnt->mnt_writers; 95 #endif 96 } 97 98 static inline struct vfsmount *mntget(struct vfsmount *mnt) 99 { 100 if (mnt) 101 atomic_inc(&mnt->mnt_count); 102 return mnt; 103 } 104 105 struct file; /* forward dec */ 106 107 extern int mnt_want_write(struct vfsmount *mnt); 108 extern int mnt_want_write_file(struct file *file); 109 extern int mnt_clone_write(struct vfsmount *mnt); 110 extern void mnt_drop_write(struct vfsmount *mnt); 111 extern void mntput_no_expire(struct vfsmount *mnt); 112 extern void mnt_pin(struct vfsmount *mnt); 113 extern void mnt_unpin(struct vfsmount *mnt); 114 extern int __mnt_is_readonly(struct vfsmount *mnt); 115 116 static inline void mntput(struct vfsmount *mnt) 117 { 118 if (mnt) { 119 mnt->mnt_expiry_mark = 0; 120 mntput_no_expire(mnt); 121 } 122 } 123 124 extern struct vfsmount *do_kern_mount(const char *fstype, int flags, 125 const char *name, void *data); 126 127 struct file_system_type; 128 extern struct vfsmount *vfs_kern_mount(struct file_system_type *type, 129 int flags, const char *name, 130 void *data); 131 132 struct nameidata; 133 134 struct path; 135 extern int do_add_mount(struct vfsmount *newmnt, struct path *path, 136 int mnt_flags, struct list_head *fslist); 137 138 extern void mark_mounts_for_expiry(struct list_head *mounts); 139 140 extern dev_t name_to_dev_t(char *name); 141 142 #endif /* _LINUX_MOUNT_H */ 143