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 #define MNT_STRICTATIME 0x80 31 32 #define MNT_SHRINKABLE 0x100 33 #define MNT_WRITE_HOLD 0x200 34 35 #define MNT_SHARED 0x1000 /* if the vfsmount is a shared mount */ 36 #define MNT_UNBINDABLE 0x2000 /* if the vfsmount is a unbindable mount */ 37 /* 38 * MNT_SHARED_MASK is the set of flags that should be cleared when a 39 * mount becomes shared. Currently, this is only the flag that says a 40 * mount cannot be bind mounted, since this is how we create a mount 41 * that shares events with another mount. If you add a new MNT_* 42 * flag, consider how it interacts with shared mounts. 43 */ 44 #define MNT_SHARED_MASK (MNT_UNBINDABLE) 45 #define MNT_PROPAGATION_MASK (MNT_SHARED | MNT_UNBINDABLE) 46 47 48 #define MNT_INTERNAL 0x4000 49 50 struct vfsmount { 51 struct list_head mnt_hash; 52 struct vfsmount *mnt_parent; /* fs we are mounted on */ 53 struct dentry *mnt_mountpoint; /* dentry of mountpoint */ 54 struct dentry *mnt_root; /* root of the mounted tree */ 55 struct super_block *mnt_sb; /* pointer to superblock */ 56 struct list_head mnt_mounts; /* list of children, anchored here */ 57 struct list_head mnt_child; /* and going through their mnt_child */ 58 int mnt_flags; 59 /* 4 bytes hole on 64bits arches */ 60 const char *mnt_devname; /* Name of device e.g. /dev/dsk/hda1 */ 61 struct list_head mnt_list; 62 struct list_head mnt_expire; /* link in fs-specific expiry list */ 63 struct list_head mnt_share; /* circular list of shared mounts */ 64 struct list_head mnt_slave_list;/* list of slave mounts */ 65 struct list_head mnt_slave; /* slave list entry */ 66 struct vfsmount *mnt_master; /* slave is on master->mnt_slave_list */ 67 struct mnt_namespace *mnt_ns; /* containing namespace */ 68 int mnt_id; /* mount identifier */ 69 int mnt_group_id; /* peer group identifier */ 70 /* 71 * We put mnt_count & mnt_expiry_mark at the end of struct vfsmount 72 * to let these frequently modified fields in a separate cache line 73 * (so that reads of mnt_flags wont ping-pong on SMP machines) 74 */ 75 atomic_t mnt_count; 76 int mnt_expiry_mark; /* true if marked for expiry */ 77 int mnt_pinned; 78 int mnt_ghosts; 79 #ifdef CONFIG_SMP 80 int __percpu *mnt_writers; 81 #else 82 int mnt_writers; 83 #endif 84 }; 85 86 static inline int *get_mnt_writers_ptr(struct vfsmount *mnt) 87 { 88 #ifdef CONFIG_SMP 89 return mnt->mnt_writers; 90 #else 91 return &mnt->mnt_writers; 92 #endif 93 } 94 95 static inline struct vfsmount *mntget(struct vfsmount *mnt) 96 { 97 if (mnt) 98 atomic_inc(&mnt->mnt_count); 99 return mnt; 100 } 101 102 struct file; /* forward dec */ 103 104 extern int mnt_want_write(struct vfsmount *mnt); 105 extern int mnt_want_write_file(struct file *file); 106 extern int mnt_clone_write(struct vfsmount *mnt); 107 extern void mnt_drop_write(struct vfsmount *mnt); 108 extern void mntput_no_expire(struct vfsmount *mnt); 109 extern void mnt_pin(struct vfsmount *mnt); 110 extern void mnt_unpin(struct vfsmount *mnt); 111 extern int __mnt_is_readonly(struct vfsmount *mnt); 112 113 static inline void mntput(struct vfsmount *mnt) 114 { 115 if (mnt) { 116 mnt->mnt_expiry_mark = 0; 117 mntput_no_expire(mnt); 118 } 119 } 120 121 extern struct vfsmount *do_kern_mount(const char *fstype, int flags, 122 const char *name, void *data); 123 124 struct file_system_type; 125 extern struct vfsmount *vfs_kern_mount(struct file_system_type *type, 126 int flags, const char *name, 127 void *data); 128 129 struct nameidata; 130 131 struct path; 132 extern int do_add_mount(struct vfsmount *newmnt, struct path *path, 133 int mnt_flags, struct list_head *fslist); 134 135 extern void mark_mounts_for_expiry(struct list_head *mounts); 136 137 extern dev_t name_to_dev_t(char *name); 138 139 #endif /* _LINUX_MOUNT_H */ 140