xref: /linux-6.15/include/linux/mount.h (revision 4bedea94)
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/list.h>
16 #include <linux/spinlock.h>
17 #include <asm/atomic.h>
18 
19 #define MNT_NOSUID	1
20 #define MNT_NODEV	2
21 #define MNT_NOEXEC	4
22 
23 struct vfsmount
24 {
25 	struct list_head mnt_hash;
26 	struct vfsmount *mnt_parent;	/* fs we are mounted on */
27 	struct dentry *mnt_mountpoint;	/* dentry of mountpoint */
28 	struct dentry *mnt_root;	/* root of the mounted tree */
29 	struct super_block *mnt_sb;	/* pointer to superblock */
30 	struct list_head mnt_mounts;	/* list of children, anchored here */
31 	struct list_head mnt_child;	/* and going through their mnt_child */
32 	atomic_t mnt_count;
33 	int mnt_flags;
34 	int mnt_expiry_mark;		/* true if marked for expiry */
35 	char *mnt_devname;		/* Name of device e.g. /dev/dsk/hda1 */
36 	struct list_head mnt_list;
37 	struct list_head mnt_fslink;	/* link in fs-specific expiry list */
38 	struct namespace *mnt_namespace; /* containing namespace */
39 };
40 
41 static inline struct vfsmount *mntget(struct vfsmount *mnt)
42 {
43 	if (mnt)
44 		atomic_inc(&mnt->mnt_count);
45 	return mnt;
46 }
47 
48 extern void __mntput(struct vfsmount *mnt);
49 
50 static inline void _mntput(struct vfsmount *mnt)
51 {
52 	if (mnt) {
53 		if (atomic_dec_and_test(&mnt->mnt_count))
54 			__mntput(mnt);
55 	}
56 }
57 
58 static inline void mntput(struct vfsmount *mnt)
59 {
60 	if (mnt) {
61 		mnt->mnt_expiry_mark = 0;
62 		_mntput(mnt);
63 	}
64 }
65 
66 extern void free_vfsmnt(struct vfsmount *mnt);
67 extern struct vfsmount *alloc_vfsmnt(const char *name);
68 extern struct vfsmount *do_kern_mount(const char *fstype, int flags,
69 				      const char *name, void *data);
70 
71 struct nameidata;
72 
73 extern int do_add_mount(struct vfsmount *newmnt, struct nameidata *nd,
74 			int mnt_flags, struct list_head *fslist);
75 
76 extern void mark_mounts_for_expiry(struct list_head *mounts);
77 
78 extern spinlock_t vfsmount_lock;
79 
80 #endif
81 #endif /* _LINUX_MOUNT_H */
82