140 lines
4.0 KiB
C
140 lines
4.0 KiB
C
/*
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*
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* Definitions for mount interface. This describes the in the kernel build
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* linkedlist with mounted filesystems.
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*
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* Author: Marco van Wieringen <mvw@planets.elm.net>
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*
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*/
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#ifndef _LINUX_MOUNT_H
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#define _LINUX_MOUNT_H
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#include <linux/types.h>
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#include <linux/list.h>
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#include <linux/nodemask.h>
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#include <linux/spinlock.h>
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#include <asm/atomic.h>
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struct super_block;
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struct vfsmount;
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struct dentry;
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struct mnt_namespace;
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#define MNT_NOSUID 0x01
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#define MNT_NODEV 0x02
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#define MNT_NOEXEC 0x04
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#define MNT_NOATIME 0x08
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#define MNT_NODIRATIME 0x10
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#define MNT_RELATIME 0x20
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#define MNT_READONLY 0x40 /* does the user want this to be r/o? */
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#define MNT_STRICTATIME 0x80
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#define MNT_SHRINKABLE 0x100
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#define MNT_WRITE_HOLD 0x200
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#define MNT_SHARED 0x1000 /* if the vfsmount is a shared mount */
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#define MNT_UNBINDABLE 0x2000 /* if the vfsmount is a unbindable mount */
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/*
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* MNT_SHARED_MASK is the set of flags that should be cleared when a
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* mount becomes shared. Currently, this is only the flag that says a
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* mount cannot be bind mounted, since this is how we create a mount
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* that shares events with another mount. If you add a new MNT_*
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* flag, consider how it interacts with shared mounts.
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*/
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#define MNT_SHARED_MASK (MNT_UNBINDABLE)
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#define MNT_PROPAGATION_MASK (MNT_SHARED | MNT_UNBINDABLE)
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#define MNT_INTERNAL 0x4000
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struct vfsmount {
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struct list_head mnt_hash;
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struct vfsmount *mnt_parent; /* fs we are mounted on */
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struct dentry *mnt_mountpoint; /* dentry of mountpoint */
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struct dentry *mnt_root; /* root of the mounted tree */
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struct super_block *mnt_sb; /* pointer to superblock */
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struct list_head mnt_mounts; /* list of children, anchored here */
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struct list_head mnt_child; /* and going through their mnt_child */
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int mnt_flags;
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/* 4 bytes hole on 64bits arches */
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const char *mnt_devname; /* Name of device e.g. /dev/dsk/hda1 */
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struct list_head mnt_list;
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struct list_head mnt_expire; /* link in fs-specific expiry list */
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struct list_head mnt_share; /* circular list of shared mounts */
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struct list_head mnt_slave_list;/* list of slave mounts */
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struct list_head mnt_slave; /* slave list entry */
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struct vfsmount *mnt_master; /* slave is on master->mnt_slave_list */
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struct mnt_namespace *mnt_ns; /* containing namespace */
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int mnt_id; /* mount identifier */
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int mnt_group_id; /* peer group identifier */
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/*
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* We put mnt_count & mnt_expiry_mark at the end of struct vfsmount
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* to let these frequently modified fields in a separate cache line
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* (so that reads of mnt_flags wont ping-pong on SMP machines)
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*/
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atomic_t mnt_count;
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int mnt_expiry_mark; /* true if marked for expiry */
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int mnt_pinned;
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int mnt_ghosts;
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#ifdef CONFIG_SMP
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int __percpu *mnt_writers;
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#else
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int mnt_writers;
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#endif
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};
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static inline int *get_mnt_writers_ptr(struct vfsmount *mnt)
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{
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#ifdef CONFIG_SMP
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return mnt->mnt_writers;
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#else
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return &mnt->mnt_writers;
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#endif
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}
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static inline struct vfsmount *mntget(struct vfsmount *mnt)
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{
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if (mnt)
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atomic_inc(&mnt->mnt_count);
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return mnt;
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}
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struct file; /* forward dec */
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extern int mnt_want_write(struct vfsmount *mnt);
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extern int mnt_want_write_file(struct file *file);
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extern int mnt_clone_write(struct vfsmount *mnt);
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extern void mnt_drop_write(struct vfsmount *mnt);
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extern void mntput_no_expire(struct vfsmount *mnt);
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extern void mnt_pin(struct vfsmount *mnt);
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extern void mnt_unpin(struct vfsmount *mnt);
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extern int __mnt_is_readonly(struct vfsmount *mnt);
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static inline void mntput(struct vfsmount *mnt)
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{
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if (mnt) {
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mnt->mnt_expiry_mark = 0;
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mntput_no_expire(mnt);
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}
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}
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extern struct vfsmount *do_kern_mount(const char *fstype, int flags,
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const char *name, void *data);
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struct file_system_type;
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extern struct vfsmount *vfs_kern_mount(struct file_system_type *type,
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int flags, const char *name,
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void *data);
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struct nameidata;
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struct path;
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extern int do_add_mount(struct vfsmount *newmnt, struct path *path,
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int mnt_flags, struct list_head *fslist);
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extern void mark_mounts_for_expiry(struct list_head *mounts);
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extern dev_t name_to_dev_t(char *name);
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#endif /* _LINUX_MOUNT_H */
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