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_IMBALANCED_WRITE_COUNT 0x200 /* just for debugging */ 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 #define MNT_PNODE_MASK 0x3000 /* propagation flag mask */ 37 38 struct vfsmount { 39 struct list_head mnt_hash; 40 struct vfsmount *mnt_parent; /* fs we are mounted on */ 41 struct dentry *mnt_mountpoint; /* dentry of mountpoint */ 42 struct dentry *mnt_root; /* root of the mounted tree */ 43 struct super_block *mnt_sb; /* pointer to superblock */ 44 struct list_head mnt_mounts; /* list of children, anchored here */ 45 struct list_head mnt_child; /* and going through their mnt_child */ 46 int mnt_flags; 47 /* 4 bytes hole on 64bits arches */ 48 const char *mnt_devname; /* Name of device e.g. /dev/dsk/hda1 */ 49 struct list_head mnt_list; 50 struct list_head mnt_expire; /* link in fs-specific expiry list */ 51 struct list_head mnt_share; /* circular list of shared mounts */ 52 struct list_head mnt_slave_list;/* list of slave mounts */ 53 struct list_head mnt_slave; /* slave list entry */ 54 struct vfsmount *mnt_master; /* slave is on master->mnt_slave_list */ 55 struct mnt_namespace *mnt_ns; /* containing namespace */ 56 int mnt_id; /* mount identifier */ 57 int mnt_group_id; /* peer group identifier */ 58 /* 59 * We put mnt_count & mnt_expiry_mark at the end of struct vfsmount 60 * to let these frequently modified fields in a separate cache line 61 * (so that reads of mnt_flags wont ping-pong on SMP machines) 62 */ 63 atomic_t mnt_count; 64 int mnt_expiry_mark; /* true if marked for expiry */ 65 int mnt_pinned; 66 int mnt_ghosts; 67 /* 68 * This value is not stable unless all of the mnt_writers[] spinlocks 69 * are held, and all mnt_writer[]s on this mount have 0 as their ->count 70 */ 71 atomic_t __mnt_writers; 72 }; 73 74 static inline struct vfsmount *mntget(struct vfsmount *mnt) 75 { 76 if (mnt) 77 atomic_inc(&mnt->mnt_count); 78 return mnt; 79 } 80 81 extern int mnt_want_write(struct vfsmount *mnt); 82 extern void mnt_drop_write(struct vfsmount *mnt); 83 extern void mntput_no_expire(struct vfsmount *mnt); 84 extern void mnt_pin(struct vfsmount *mnt); 85 extern void mnt_unpin(struct vfsmount *mnt); 86 extern int __mnt_is_readonly(struct vfsmount *mnt); 87 88 static inline void mntput(struct vfsmount *mnt) 89 { 90 if (mnt) { 91 mnt->mnt_expiry_mark = 0; 92 mntput_no_expire(mnt); 93 } 94 } 95 96 extern struct vfsmount *do_kern_mount(const char *fstype, int flags, 97 const char *name, void *data); 98 99 struct file_system_type; 100 extern struct vfsmount *vfs_kern_mount(struct file_system_type *type, 101 int flags, const char *name, 102 void *data); 103 104 struct nameidata; 105 106 struct path; 107 extern int do_add_mount(struct vfsmount *newmnt, struct path *path, 108 int mnt_flags, struct list_head *fslist); 109 110 extern void mark_mounts_for_expiry(struct list_head *mounts); 111 112 extern spinlock_t vfsmount_lock; 113 extern dev_t name_to_dev_t(char *name); 114 115 #endif /* _LINUX_MOUNT_H */ 116