xref: /linux-6.15/include/linux/mount.h (revision de2fe5e0)
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/spinlock.h>
18 #include <asm/atomic.h>
19 
20 #define MNT_NOSUID	0x01
21 #define MNT_NODEV	0x02
22 #define MNT_NOEXEC	0x04
23 #define MNT_NOATIME	0x08
24 #define MNT_NODIRATIME	0x10
25 
26 #define MNT_SHARED	0x1000	/* if the vfsmount is a shared mount */
27 #define MNT_UNBINDABLE	0x2000	/* if the vfsmount is a unbindable mount */
28 #define MNT_PNODE_MASK	0x3000	/* propogation flag mask */
29 
30 struct vfsmount {
31 	struct list_head mnt_hash;
32 	struct vfsmount *mnt_parent;	/* fs we are mounted on */
33 	struct dentry *mnt_mountpoint;	/* dentry of mountpoint */
34 	struct dentry *mnt_root;	/* root of the mounted tree */
35 	struct super_block *mnt_sb;	/* pointer to superblock */
36 	struct list_head mnt_mounts;	/* list of children, anchored here */
37 	struct list_head mnt_child;	/* and going through their mnt_child */
38 	atomic_t mnt_count;
39 	int mnt_flags;
40 	int mnt_expiry_mark;		/* true if marked for expiry */
41 	char *mnt_devname;		/* Name of device e.g. /dev/dsk/hda1 */
42 	struct list_head mnt_list;
43 	struct list_head mnt_expire;	/* link in fs-specific expiry list */
44 	struct list_head mnt_share;	/* circular list of shared mounts */
45 	struct list_head mnt_slave_list;/* list of slave mounts */
46 	struct list_head mnt_slave;	/* slave list entry */
47 	struct vfsmount *mnt_master;	/* slave is on master->mnt_slave_list */
48 	struct namespace *mnt_namespace; /* containing namespace */
49 	int mnt_pinned;
50 };
51 
52 static inline struct vfsmount *mntget(struct vfsmount *mnt)
53 {
54 	if (mnt)
55 		atomic_inc(&mnt->mnt_count);
56 	return mnt;
57 }
58 
59 extern void mntput_no_expire(struct vfsmount *mnt);
60 extern void mnt_pin(struct vfsmount *mnt);
61 extern void mnt_unpin(struct vfsmount *mnt);
62 
63 static inline void mntput(struct vfsmount *mnt)
64 {
65 	if (mnt) {
66 		mnt->mnt_expiry_mark = 0;
67 		mntput_no_expire(mnt);
68 	}
69 }
70 
71 extern void free_vfsmnt(struct vfsmount *mnt);
72 extern struct vfsmount *alloc_vfsmnt(const char *name);
73 extern struct vfsmount *do_kern_mount(const char *fstype, int flags,
74 				      const char *name, void *data);
75 
76 struct nameidata;
77 
78 extern int do_add_mount(struct vfsmount *newmnt, struct nameidata *nd,
79 			int mnt_flags, struct list_head *fslist);
80 
81 extern void mark_mounts_for_expiry(struct list_head *mounts);
82 
83 extern spinlock_t vfsmount_lock;
84 extern dev_t name_to_dev_t(char *name);
85 
86 #endif
87 #endif /* _LINUX_MOUNT_H */
88