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 #define MNT_PNODE_MASK 0x3000 /* propagation flag mask */ 38 39 struct vfsmount { 40 struct list_head mnt_hash; 41 struct vfsmount *mnt_parent; /* fs we are mounted on */ 42 struct dentry *mnt_mountpoint; /* dentry of mountpoint */ 43 struct dentry *mnt_root; /* root of the mounted tree */ 44 struct super_block *mnt_sb; /* pointer to superblock */ 45 struct list_head mnt_mounts; /* list of children, anchored here */ 46 struct list_head mnt_child; /* and going through their mnt_child */ 47 int mnt_flags; 48 /* 4 bytes hole on 64bits arches */ 49 const char *mnt_devname; /* Name of device e.g. /dev/dsk/hda1 */ 50 struct list_head mnt_list; 51 struct list_head mnt_expire; /* link in fs-specific expiry list */ 52 struct list_head mnt_share; /* circular list of shared mounts */ 53 struct list_head mnt_slave_list;/* list of slave mounts */ 54 struct list_head mnt_slave; /* slave list entry */ 55 struct vfsmount *mnt_master; /* slave is on master->mnt_slave_list */ 56 struct mnt_namespace *mnt_ns; /* containing namespace */ 57 int mnt_id; /* mount identifier */ 58 int mnt_group_id; /* peer group identifier */ 59 /* 60 * We put mnt_count & mnt_expiry_mark at the end of struct vfsmount 61 * to let these frequently modified fields in a separate cache line 62 * (so that reads of mnt_flags wont ping-pong on SMP machines) 63 */ 64 atomic_t mnt_count; 65 int mnt_expiry_mark; /* true if marked for expiry */ 66 int mnt_pinned; 67 int mnt_ghosts; 68 #ifdef CONFIG_SMP 69 int *mnt_writers; 70 #else 71 int mnt_writers; 72 #endif 73 }; 74 75 static inline int *get_mnt_writers_ptr(struct vfsmount *mnt) 76 { 77 #ifdef CONFIG_SMP 78 return mnt->mnt_writers; 79 #else 80 return &mnt->mnt_writers; 81 #endif 82 } 83 84 static inline struct vfsmount *mntget(struct vfsmount *mnt) 85 { 86 if (mnt) 87 atomic_inc(&mnt->mnt_count); 88 return mnt; 89 } 90 91 struct file; /* forward dec */ 92 93 extern int mnt_want_write(struct vfsmount *mnt); 94 extern int mnt_want_write_file(struct file *file); 95 extern int mnt_clone_write(struct vfsmount *mnt); 96 extern void mnt_drop_write(struct vfsmount *mnt); 97 extern void mntput_no_expire(struct vfsmount *mnt); 98 extern void mnt_pin(struct vfsmount *mnt); 99 extern void mnt_unpin(struct vfsmount *mnt); 100 extern int __mnt_is_readonly(struct vfsmount *mnt); 101 102 static inline void mntput(struct vfsmount *mnt) 103 { 104 if (mnt) { 105 mnt->mnt_expiry_mark = 0; 106 mntput_no_expire(mnt); 107 } 108 } 109 110 extern struct vfsmount *do_kern_mount(const char *fstype, int flags, 111 const char *name, void *data); 112 113 struct file_system_type; 114 extern struct vfsmount *vfs_kern_mount(struct file_system_type *type, 115 int flags, const char *name, 116 void *data); 117 118 struct nameidata; 119 120 struct path; 121 extern int do_add_mount(struct vfsmount *newmnt, struct path *path, 122 int mnt_flags, struct list_head *fslist); 123 124 extern void mark_mounts_for_expiry(struct list_head *mounts); 125 126 extern spinlock_t vfsmount_lock; 127 extern dev_t name_to_dev_t(char *name); 128 129 #endif /* _LINUX_MOUNT_H */ 130