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 * Version: $Id: mount.h,v 2.0 1996/11/17 16:48:14 mvw Exp mvw $ 9 * 10 */ 11 #ifndef _LINUX_MOUNT_H 12 #define _LINUX_MOUNT_H 13 #ifdef __KERNEL__ 14 15 #include <linux/types.h> 16 #include <linux/list.h> 17 #include <linux/nodemask.h> 18 #include <linux/spinlock.h> 19 #include <asm/atomic.h> 20 21 struct super_block; 22 struct vfsmount; 23 struct dentry; 24 struct mnt_namespace; 25 26 #define MNT_NOSUID 0x01 27 #define MNT_NODEV 0x02 28 #define MNT_NOEXEC 0x04 29 #define MNT_NOATIME 0x08 30 #define MNT_NODIRATIME 0x10 31 #define MNT_RELATIME 0x20 32 #define MNT_READONLY 0x40 /* does the user want this to be r/o? */ 33 34 #define MNT_SHRINKABLE 0x100 35 #define MNT_IMBALANCED_WRITE_COUNT 0x200 /* just for debugging */ 36 37 #define MNT_SHARED 0x1000 /* if the vfsmount is a shared mount */ 38 #define MNT_UNBINDABLE 0x2000 /* if the vfsmount is a unbindable mount */ 39 #define MNT_PNODE_MASK 0x3000 /* propagation flag mask */ 40 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 */ 51 char *mnt_devname; /* Name of device e.g. /dev/dsk/hda1 */ 52 struct list_head mnt_list; 53 struct list_head mnt_expire; /* link in fs-specific expiry list */ 54 struct list_head mnt_share; /* circular list of shared mounts */ 55 struct list_head mnt_slave_list;/* list of slave mounts */ 56 struct list_head mnt_slave; /* slave list entry */ 57 struct vfsmount *mnt_master; /* slave is on master->mnt_slave_list */ 58 struct mnt_namespace *mnt_ns; /* containing namespace */ 59 int mnt_id; /* mount identifier */ 60 int mnt_group_id; /* peer group identifier */ 61 /* 62 * We put mnt_count & mnt_expiry_mark at the end of struct vfsmount 63 * to let these frequently modified fields in a separate cache line 64 * (so that reads of mnt_flags wont ping-pong on SMP machines) 65 */ 66 atomic_t mnt_count; 67 int mnt_expiry_mark; /* true if marked for expiry */ 68 int mnt_pinned; 69 int mnt_ghosts; 70 /* 71 * This value is not stable unless all of the mnt_writers[] spinlocks 72 * are held, and all mnt_writer[]s on this mount have 0 as their ->count 73 */ 74 atomic_t __mnt_writers; 75 }; 76 77 static inline struct vfsmount *mntget(struct vfsmount *mnt) 78 { 79 if (mnt) 80 atomic_inc(&mnt->mnt_count); 81 return mnt; 82 } 83 84 extern int mnt_want_write(struct vfsmount *mnt); 85 extern void mnt_drop_write(struct vfsmount *mnt); 86 extern void mntput_no_expire(struct vfsmount *mnt); 87 extern void mnt_pin(struct vfsmount *mnt); 88 extern void mnt_unpin(struct vfsmount *mnt); 89 extern int __mnt_is_readonly(struct vfsmount *mnt); 90 91 static inline void mntput(struct vfsmount *mnt) 92 { 93 if (mnt) { 94 mnt->mnt_expiry_mark = 0; 95 mntput_no_expire(mnt); 96 } 97 } 98 99 extern struct vfsmount *do_kern_mount(const char *fstype, int flags, 100 const char *name, void *data); 101 102 struct file_system_type; 103 extern struct vfsmount *vfs_kern_mount(struct file_system_type *type, 104 int flags, const char *name, 105 void *data); 106 107 struct nameidata; 108 109 extern int do_add_mount(struct vfsmount *newmnt, struct nameidata *nd, 110 int mnt_flags, struct list_head *fslist); 111 112 extern void mark_mounts_for_expiry(struct list_head *mounts); 113 114 extern spinlock_t vfsmount_lock; 115 extern dev_t name_to_dev_t(char *name); 116 117 #endif 118 #endif /* _LINUX_MOUNT_H */ 119