| 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 | |
| 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 */ |