xref: /linux-6.15/include/linux/mount.h (revision 20dd026d)
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	1
21 #define MNT_NODEV	2
22 #define MNT_NOEXEC	4
23 
24 struct vfsmount
25 {
26 	struct list_head mnt_hash;
27 	struct vfsmount *mnt_parent;	/* fs we are mounted on */
28 	struct dentry *mnt_mountpoint;	/* dentry of mountpoint */
29 	struct dentry *mnt_root;	/* root of the mounted tree */
30 	struct super_block *mnt_sb;	/* pointer to superblock */
31 	struct list_head mnt_mounts;	/* list of children, anchored here */
32 	struct list_head mnt_child;	/* and going through their mnt_child */
33 	atomic_t mnt_count;
34 	int mnt_flags;
35 	int mnt_expiry_mark;		/* true if marked for expiry */
36 	char *mnt_devname;		/* Name of device e.g. /dev/dsk/hda1 */
37 	struct list_head mnt_list;
38 	struct list_head mnt_expire;	/* link in fs-specific expiry list */
39 	struct namespace *mnt_namespace; /* containing namespace */
40 };
41 
42 static inline struct vfsmount *mntget(struct vfsmount *mnt)
43 {
44 	if (mnt)
45 		atomic_inc(&mnt->mnt_count);
46 	return mnt;
47 }
48 
49 extern void __mntput(struct vfsmount *mnt);
50 
51 static inline void mntput_no_expire(struct vfsmount *mnt)
52 {
53 	if (mnt) {
54 		if (atomic_dec_and_test(&mnt->mnt_count))
55 			__mntput(mnt);
56 	}
57 }
58 
59 static inline void mntput(struct vfsmount *mnt)
60 {
61 	if (mnt) {
62 		mnt->mnt_expiry_mark = 0;
63 		mntput_no_expire(mnt);
64 	}
65 }
66 
67 extern void free_vfsmnt(struct vfsmount *mnt);
68 extern struct vfsmount *alloc_vfsmnt(const char *name);
69 extern struct vfsmount *do_kern_mount(const char *fstype, int flags,
70 				      const char *name, void *data);
71 
72 struct nameidata;
73 
74 extern int do_add_mount(struct vfsmount *newmnt, struct nameidata *nd,
75 			int mnt_flags, struct list_head *fslist);
76 
77 extern void mark_mounts_for_expiry(struct list_head *mounts);
78 
79 extern spinlock_t vfsmount_lock;
80 extern dev_t name_to_dev_t(char *name);
81 
82 #endif
83 #endif /* _LINUX_MOUNT_H */
84