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https://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson
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406fea7999
Several flags are updated and checked only under namespace_sem; we are already making use of that when we are checking them without mount_lock, but we have to hold mount_lock for all updates, which makes things clumsier than they have to be. Take MNT_SHARED, MNT_UNBINDABLE, MNT_MARKED and MNT_UMOUNT_CANDIDATE into a separate field (->mnt_t_flags), renaming them to T_SHARED, etc. to avoid confusion. All accesses must be under namespace_sem. That changes locking requirements for mnt_change_propagation() and set_mnt_shared() - only namespace_sem is needed now. The same goes for SET_MNT_MARKED et.al. There might be more flags moved from ->mnt_flags to that field; this is just the initial set. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
114 lines
3.5 KiB
C
114 lines
3.5 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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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 <asm/barrier.h>
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struct super_block;
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struct dentry;
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struct user_namespace;
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struct mnt_idmap;
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struct file_system_type;
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struct fs_context;
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struct file;
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struct path;
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enum mount_flags {
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MNT_NOSUID = 0x01,
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MNT_NODEV = 0x02,
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MNT_NOEXEC = 0x04,
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MNT_NOATIME = 0x08,
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MNT_NODIRATIME = 0x10,
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MNT_RELATIME = 0x20,
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MNT_READONLY = 0x40, /* does the user want this to be r/o? */
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MNT_NOSYMFOLLOW = 0x80,
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MNT_SHRINKABLE = 0x100,
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MNT_WRITE_HOLD = 0x200,
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MNT_INTERNAL = 0x4000,
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MNT_LOCK_ATIME = 0x040000,
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MNT_LOCK_NOEXEC = 0x080000,
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MNT_LOCK_NOSUID = 0x100000,
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MNT_LOCK_NODEV = 0x200000,
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MNT_LOCK_READONLY = 0x400000,
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MNT_LOCKED = 0x800000,
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MNT_DOOMED = 0x1000000,
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MNT_SYNC_UMOUNT = 0x2000000,
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MNT_UMOUNT = 0x8000000,
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MNT_USER_SETTABLE_MASK = MNT_NOSUID | MNT_NODEV | MNT_NOEXEC
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| MNT_NOATIME | MNT_NODIRATIME | MNT_RELATIME
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| MNT_READONLY | MNT_NOSYMFOLLOW,
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MNT_ATIME_MASK = MNT_NOATIME | MNT_NODIRATIME | MNT_RELATIME,
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MNT_INTERNAL_FLAGS = MNT_WRITE_HOLD | MNT_INTERNAL | MNT_DOOMED |
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MNT_SYNC_UMOUNT | MNT_LOCKED
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};
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struct vfsmount {
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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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int mnt_flags;
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struct mnt_idmap *mnt_idmap;
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} __randomize_layout;
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static inline struct mnt_idmap *mnt_idmap(const struct vfsmount *mnt)
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{
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/* Pairs with smp_store_release() in do_idmap_mount(). */
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return READ_ONCE(mnt->mnt_idmap);
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}
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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 void mnt_drop_write(struct vfsmount *mnt);
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extern void mnt_drop_write_file(struct file *file);
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extern void mntput(struct vfsmount *mnt);
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extern struct vfsmount *mntget(struct vfsmount *mnt);
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extern void mnt_make_shortterm(struct vfsmount *mnt);
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extern struct vfsmount *mnt_clone_internal(const struct path *path);
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extern bool __mnt_is_readonly(struct vfsmount *mnt);
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extern bool mnt_may_suid(struct vfsmount *mnt);
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extern struct vfsmount *clone_private_mount(const struct path *path);
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int mnt_get_write_access(struct vfsmount *mnt);
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void mnt_put_write_access(struct vfsmount *mnt);
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extern struct vfsmount *fc_mount(struct fs_context *fc);
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extern struct vfsmount *fc_mount_longterm(struct fs_context *fc);
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extern struct vfsmount *vfs_create_mount(struct fs_context *fc);
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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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extern void mnt_set_expiry(struct vfsmount *mnt, struct list_head *expiry_list);
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extern void mark_mounts_for_expiry(struct list_head *mounts);
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extern bool path_is_mountpoint(const struct path *path);
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extern bool our_mnt(struct vfsmount *mnt);
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extern struct vfsmount *kern_mount(struct file_system_type *);
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extern void kern_unmount(struct vfsmount *mnt);
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extern int may_umount_tree(struct vfsmount *);
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extern int may_umount(struct vfsmount *);
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int do_mount(const char *, const char __user *,
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const char *, unsigned long, void *);
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extern struct path *collect_paths(const struct path *, struct path *, unsigned);
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extern void drop_collected_paths(struct path *, struct path *);
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extern void kern_unmount_array(struct vfsmount *mnt[], unsigned int num);
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extern int cifs_root_data(char **dev, char **opts);
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#endif /* _LINUX_MOUNT_H */
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