mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-12-18 15:36:46 +07:00
c64cd6e34e
... and get rid of a bunch of bugs in it. Background: the reason for path_mountpoint() is that umount() really doesn't want attempts to revalidate the root of what it's trying to umount. The thing we want to avoid actually happen from complete_walk(); solution was to do something parallel to normal path_lookupat() and it both went overboard and got the boilerplate subtly (and not so subtly) wrong. A better solution is to do pretty much what the normal path_lookupat() does, but instead of complete_walk() do unlazy_walk(). All it takes to avoid that ->d_weak_revalidate() call... mountpoint_last() goes away, along with everything it got wrong, and so does the magic around LOOKUP_NO_REVAL. Another source of bugs is that when we traverse mounts at the final location (and we need to do that - umount . expects to get whatever's overmounting ., if any, out of the lookup) we really ought to take care of ->d_manage() - as it is, manual umount of autofs automount in progress can lead to unpleasant surprises for the daemon. Easily solved by using handle_lookup_down() instead of follow_mount(). Tested-by: Ian Kent <raven@themaw.net> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
95 lines
3.3 KiB
C
95 lines
3.3 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
|
|
#ifndef _LINUX_NAMEI_H
|
|
#define _LINUX_NAMEI_H
|
|
|
|
#include <linux/kernel.h>
|
|
#include <linux/path.h>
|
|
#include <linux/fcntl.h>
|
|
#include <linux/errno.h>
|
|
|
|
enum { MAX_NESTED_LINKS = 8 };
|
|
|
|
#define MAXSYMLINKS 40
|
|
|
|
/*
|
|
* Type of the last component on LOOKUP_PARENT
|
|
*/
|
|
enum {LAST_NORM, LAST_ROOT, LAST_DOT, LAST_DOTDOT, LAST_BIND};
|
|
|
|
/* pathwalk mode */
|
|
#define LOOKUP_FOLLOW 0x0001 /* follow links at the end */
|
|
#define LOOKUP_DIRECTORY 0x0002 /* require a directory */
|
|
#define LOOKUP_AUTOMOUNT 0x0004 /* force terminal automount */
|
|
#define LOOKUP_EMPTY 0x4000 /* accept empty path [user_... only] */
|
|
#define LOOKUP_DOWN 0x8000 /* follow mounts in the starting point */
|
|
|
|
#define LOOKUP_REVAL 0x0020 /* tell ->d_revalidate() to trust no cache */
|
|
#define LOOKUP_RCU 0x0040 /* RCU pathwalk mode; semi-internal */
|
|
|
|
/* These tell filesystem methods that we are dealing with the final component... */
|
|
#define LOOKUP_OPEN 0x0100 /* ... in open */
|
|
#define LOOKUP_CREATE 0x0200 /* ... in object creation */
|
|
#define LOOKUP_EXCL 0x0400 /* ... in exclusive creation */
|
|
#define LOOKUP_RENAME_TARGET 0x0800 /* ... in destination of rename() */
|
|
|
|
/* internal use only */
|
|
#define LOOKUP_PARENT 0x0010
|
|
#define LOOKUP_JUMPED 0x1000
|
|
#define LOOKUP_ROOT 0x2000
|
|
#define LOOKUP_ROOT_GRABBED 0x0008
|
|
|
|
extern int path_pts(struct path *path);
|
|
|
|
extern int user_path_at_empty(int, const char __user *, unsigned, struct path *, int *empty);
|
|
|
|
static inline int user_path_at(int dfd, const char __user *name, unsigned flags,
|
|
struct path *path)
|
|
{
|
|
return user_path_at_empty(dfd, name, flags, path, NULL);
|
|
}
|
|
|
|
extern int kern_path(const char *, unsigned, struct path *);
|
|
|
|
extern struct dentry *kern_path_create(int, const char *, struct path *, unsigned int);
|
|
extern struct dentry *user_path_create(int, const char __user *, struct path *, unsigned int);
|
|
extern void done_path_create(struct path *, struct dentry *);
|
|
extern struct dentry *kern_path_locked(const char *, struct path *);
|
|
extern int kern_path_mountpoint(int, const char *, struct path *, unsigned int);
|
|
|
|
extern struct dentry *try_lookup_one_len(const char *, struct dentry *, int);
|
|
extern struct dentry *lookup_one_len(const char *, struct dentry *, int);
|
|
extern struct dentry *lookup_one_len_unlocked(const char *, struct dentry *, int);
|
|
extern struct dentry *lookup_positive_unlocked(const char *, struct dentry *, int);
|
|
|
|
extern int follow_down_one(struct path *);
|
|
extern int follow_down(struct path *);
|
|
extern int follow_up(struct path *);
|
|
|
|
extern struct dentry *lock_rename(struct dentry *, struct dentry *);
|
|
extern void unlock_rename(struct dentry *, struct dentry *);
|
|
|
|
extern void nd_jump_link(struct path *path);
|
|
|
|
static inline void nd_terminate_link(void *name, size_t len, size_t maxlen)
|
|
{
|
|
((char *) name)[min(len, maxlen)] = '\0';
|
|
}
|
|
|
|
/**
|
|
* retry_estale - determine whether the caller should retry an operation
|
|
* @error: the error that would currently be returned
|
|
* @flags: flags being used for next lookup attempt
|
|
*
|
|
* Check to see if the error code was -ESTALE, and then determine whether
|
|
* to retry the call based on whether "flags" already has LOOKUP_REVAL set.
|
|
*
|
|
* Returns true if the caller should try the operation again.
|
|
*/
|
|
static inline bool
|
|
retry_estale(const long error, const unsigned int flags)
|
|
{
|
|
return error == -ESTALE && !(flags & LOOKUP_REVAL);
|
|
}
|
|
|
|
#endif /* _LINUX_NAMEI_H */
|