Commit 42bc6793 authored by Steve French's avatar Steve French
Browse files

Merge tag 'pull-lock_rename_child' of... 

Merge tag 'pull-lock_rename_child' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

 into ksmbd-for-next

lock_rename_child() (for ksmbd folks)

Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parents 457391b0 9bc37e04

fs/internal.h

+0 −2
Original line number Diff line number Diff line
@@ -59,8 +59,6 @@ extern int finish_clean_context(struct fs_context *fc); 
 */

extern int filename_lookup(int dfd, struct filename *name, unsigned flags,

			   struct path *path, struct path *root);

extern int vfs_path_lookup(struct dentry *, struct vfsmount *,

			   const char *, unsigned int, struct path *);

int do_rmdir(int dfd, struct filename *name);

int do_unlinkat(int dfd, struct filename *name);

int may_linkat(struct mnt_idmap *idmap, const struct path *link);

fs/ksmbd/vfs.c

+0 −2
Original line number Diff line number Diff line
@@ -19,8 +19,6 @@ 
#include <linux/sched/xacct.h>

#include <linux/crc32c.h>



#include "../internal.h"	/* for vfs_path_lookup */



#include "glob.h"

#include "oplock.h"

#include "connection.h"

fs/namei.c

+57 −11
Original line number Diff line number Diff line
@@ -2980,20 +2980,10 @@ static inline int may_create(struct mnt_idmap *idmap, 
	return inode_permission(idmap, dir, MAY_WRITE | MAY_EXEC);

}



/*

 * p1 and p2 should be directories on the same fs.

 */

struct dentry *lock_rename(struct dentry *p1, struct dentry *p2)

static struct dentry *lock_two_directories(struct dentry *p1, struct dentry *p2)

{

	struct dentry *p;



	if (p1 == p2) {

		inode_lock_nested(p1->d_inode, I_MUTEX_PARENT);

		return NULL;

	}



	mutex_lock(&p1->d_sb->s_vfs_rename_mutex);



	p = d_ancestor(p2, p1);

	if (p) {

		inode_lock_nested(p2->d_inode, I_MUTEX_PARENT);
@@ -3012,8 +3002,64 @@ struct dentry *lock_rename(struct dentry *p1, struct dentry *p2) 
	inode_lock_nested(p2->d_inode, I_MUTEX_PARENT2);

	return NULL;

}



/*

 * p1 and p2 should be directories on the same fs.

 */

struct dentry *lock_rename(struct dentry *p1, struct dentry *p2)

{

	if (p1 == p2) {

		inode_lock_nested(p1->d_inode, I_MUTEX_PARENT);

		return NULL;

	}



	mutex_lock(&p1->d_sb->s_vfs_rename_mutex);

	return lock_two_directories(p1, p2);

}

EXPORT_SYMBOL(lock_rename);



/*

 * c1 and p2 should be on the same fs.

 */

struct dentry *lock_rename_child(struct dentry *c1, struct dentry *p2)

{

	if (READ_ONCE(c1->d_parent) == p2) {

		/*

		 * hopefully won't need to touch ->s_vfs_rename_mutex at all.

		 */

		inode_lock_nested(p2->d_inode, I_MUTEX_PARENT);

		/*

		 * now that p2 is locked, nobody can move in or out of it,

		 * so the test below is safe.

		 */

		if (likely(c1->d_parent == p2))

			return NULL;



		/*

		 * c1 got moved out of p2 while we'd been taking locks;

		 * unlock and fall back to slow case.

		 */

		inode_unlock(p2->d_inode);

	}



	mutex_lock(&c1->d_sb->s_vfs_rename_mutex);

	/*

	 * nobody can move out of any directories on this fs.

	 */

	if (likely(c1->d_parent != p2))

		return lock_two_directories(c1->d_parent, p2);



	/*

	 * c1 got moved into p2 while we were taking locks;

	 * we need p2 locked and ->s_vfs_rename_mutex unlocked,

	 * for consistency with lock_rename().

	 */

	inode_lock_nested(p2->d_inode, I_MUTEX_PARENT);

	mutex_unlock(&c1->d_sb->s_vfs_rename_mutex);

	return NULL;

}

EXPORT_SYMBOL(lock_rename_child);



void unlock_rename(struct dentry *p1, struct dentry *p2)

{

	inode_unlock(p1->d_inode);

include/linux/namei.h

+3 −0
Original line number Diff line number Diff line
@@ -63,6 +63,8 @@ extern struct dentry *kern_path_create(int, const char *, struct path *, unsigne 
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 *);

int vfs_path_lookup(struct dentry *, struct vfsmount *, const char *,

		    unsigned int, struct path *);



extern struct dentry *try_lookup_one_len(const char *, struct dentry *, int);

extern struct dentry *lookup_one_len(const char *, struct dentry *, int);
@@ -81,6 +83,7 @@ extern int follow_down(struct path *path, unsigned int flags); 
extern int follow_up(struct path *);



extern struct dentry *lock_rename(struct dentry *, struct dentry *);

extern struct dentry *lock_rename_child(struct dentry *, struct dentry *);

extern void unlock_rename(struct dentry *, struct dentry *);



extern int __must_check nd_jump_link(const struct path *path);