[PATCH 1/4] ksmbd: remove internal.h include

[PATCH 1/4] ksmbd: remove internal.h include

[Namjae Jeon]

Since vfs_path_lookup() is exported, It should not be internal.
Move vfs_path_lookup prototype in internal.h to linux/namei.h.

Suggested-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
---
 fs/internal.h         | 2 --
 fs/ksmbd/vfs.c        | 2 --
 include/linux/namei.h | 2 ++
 3 files changed, 2 insertions(+), 4 deletions(-)

diff --git a/fs/internal.h b/fs/internal.h
index 8590c973c2f4..deee2367df44 100644
--- a/fs/internal.h
+++ b/fs/internal.h
@@ -58,8 +58,6 @@ 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 user_namespace *mnt_userns, struct path *link);
diff --git a/fs/ksmbd/vfs.c b/fs/ksmbd/vfs.c
index 19d36393974c..a1ab0aaceba5 100644
--- a/fs/ksmbd/vfs.c
+++ b/fs/ksmbd/vfs.c
@@ -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"
diff --git a/include/linux/namei.h b/include/linux/namei.h
index e89329bb3134..4858c3cdf7c6 100644
--- a/include/linux/namei.h
+++ b/include/linux/namei.h
@@ -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);
-- 
2.25.1

[PATCH 2/4] ksmbd: remove filename in ksmbd_file

[Namjae Jeon]

If the filename is change by underlying rename the server, fp->filename
and real filename can be different. This patch remove the uses of
fp->filename in ksmbd and replace it with d_path().

Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
---
 fs/ksmbd/misc.c      | 40 +++++++++++++++++++++++++++++++---------
 fs/ksmbd/misc.h      |  3 ++-
 fs/ksmbd/oplock.c    | 30 ------------------------------
 fs/ksmbd/oplock.h    |  2 --
 fs/ksmbd/smb2pdu.c   | 21 +++++++--------------
 fs/ksmbd/vfs.c       |  6 ++----
 fs/ksmbd/vfs_cache.c |  1 -
 fs/ksmbd/vfs_cache.h |  1 -
 8 files changed, 42 insertions(+), 62 deletions(-)

diff --git a/fs/ksmbd/misc.c b/fs/ksmbd/misc.c
index 60e7ac62c917..bca29b2a190d 100644
--- a/fs/ksmbd/misc.c
+++ b/fs/ksmbd/misc.c
@@ -158,19 +158,41 @@ int parse_stream_name(char *filename, char **stream_name, int *s_type)
  * Return : windows path string or error
  */
 
-char *convert_to_nt_pathname(char *filename)
+char *convert_to_nt_pathname(struct ksmbd_share_config *share,
+			     struct path *path)
 {
-	char *ab_pathname;
+	char *pathname, *ab_pathname, *nt_pathname = NULL;
+	int share_path_len = strlen(share->path);
 
-	if (strlen(filename) == 0)
-		filename = "\\";
+	pathname = kmalloc(PATH_MAX, GFP_KERNEL);
+	if (!pathname)
+		return ERR_PTR(-EACCES);
 
-	ab_pathname = kstrdup(filename, GFP_KERNEL);
-	if (!ab_pathname)
-		return NULL;
+	ab_pathname = d_path(path, pathname, PATH_MAX);
+	if (IS_ERR(ab_pathname)) {
+		nt_pathname = ERR_PTR(-EACCES);
+		goto free_pathname;
+	}
+
+	if (strncmp(ab_pathname, share->path, share_path_len)) {
+		nt_pathname = ERR_PTR(-EACCES);
+		goto free_pathname;
+	}
+
+	nt_pathname = kzalloc(strlen(&ab_pathname[share_path_len]) + 1, GFP_KERNEL);
+	if (!nt_pathname) {
+		nt_pathname = ERR_PTR(-ENOMEM);
+		goto free_pathname;
+	}
+	if (ab_pathname[share_path_len] == '\0')
+		strcpy(nt_pathname, "/");
+	strcat(nt_pathname, &ab_pathname[share_path_len]);
+
+	ksmbd_conv_path_to_windows(nt_pathname);
 
-	ksmbd_conv_path_to_windows(ab_pathname);
-	return ab_pathname;
+free_pathname:
+	kfree(pathname);
+	return nt_pathname;
 }
 
 int get_nlink(struct kstat *st)
diff --git a/fs/ksmbd/misc.h b/fs/ksmbd/misc.h
index 253366bd0951..aae2a252945f 100644
--- a/fs/ksmbd/misc.h
+++ b/fs/ksmbd/misc.h
@@ -14,7 +14,8 @@ struct ksmbd_file;
 int match_pattern(const char *str, size_t len, const char *pattern);
 int ksmbd_validate_filename(char *filename);
 int parse_stream_name(char *filename, char **stream_name, int *s_type);
-char *convert_to_nt_pathname(char *filename);
+char *convert_to_nt_pathname(struct ksmbd_share_config *share,
+			     struct path *path);
 int get_nlink(struct kstat *st);
 void ksmbd_conv_path_to_unix(char *path);
 void ksmbd_strip_last_slash(char *path);
diff --git a/fs/ksmbd/oplock.c b/fs/ksmbd/oplock.c
index 077b8761d099..5db5cba67d62 100644
--- a/fs/ksmbd/oplock.c
+++ b/fs/ksmbd/oplock.c
@@ -1694,33 +1694,3 @@ struct oplock_info *lookup_lease_in_table(struct ksmbd_conn *conn,
 	read_unlock(&lease_list_lock);
 	return ret_op;
 }
-
-int smb2_check_durable_oplock(struct ksmbd_file *fp,
-			      struct lease_ctx_info *lctx, char *name)
-{
-	struct oplock_info *opinfo = opinfo_get(fp);
-	int ret = 0;
-
-	if (opinfo && opinfo->is_lease) {
-		if (!lctx) {
-			pr_err("open does not include lease\n");
-			ret = -EBADF;
-			goto out;
-		}
-		if (memcmp(opinfo->o_lease->lease_key, lctx->lease_key,
-			   SMB2_LEASE_KEY_SIZE)) {
-			pr_err("invalid lease key\n");
-			ret = -EBADF;
-			goto out;
-		}
-		if (name && strcmp(fp->filename, name)) {
-			pr_err("invalid name reconnect %s\n", name);
-			ret = -EINVAL;
-			goto out;
-		}
-	}
-out:
-	if (opinfo)
-		opinfo_put(opinfo);
-	return ret;
-}
diff --git a/fs/ksmbd/oplock.h b/fs/ksmbd/oplock.h
index 0cf7a2b5bbc0..09753448f779 100644
--- a/fs/ksmbd/oplock.h
+++ b/fs/ksmbd/oplock.h
@@ -124,6 +124,4 @@ struct oplock_info *lookup_lease_in_table(struct ksmbd_conn *conn,
 int find_same_lease_key(struct ksmbd_session *sess, struct ksmbd_inode *ci,
 			struct lease_ctx_info *lctx);
 void destroy_lease_table(struct ksmbd_conn *conn);
-int smb2_check_durable_oplock(struct ksmbd_file *fp,
-			      struct lease_ctx_info *lctx, char *name);
 #endif /* __KSMBD_OPLOCK_H */
diff --git a/fs/ksmbd/smb2pdu.c b/fs/ksmbd/smb2pdu.c
index 67e8e28e3fc3..3151ab7d7410 100644
--- a/fs/ksmbd/smb2pdu.c
+++ b/fs/ksmbd/smb2pdu.c
@@ -2922,7 +2922,6 @@ int smb2_open(struct ksmbd_work *work)
 		goto err_out;
 	}
 
-	fp->filename = name;
 	fp->cdoption = req->CreateDisposition;
 	fp->daccess = daccess;
 	fp->saccess = req->ShareAccess;
@@ -3274,14 +3273,13 @@ int smb2_open(struct ksmbd_work *work)
 		if (!rsp->hdr.Status)
 			rsp->hdr.Status = STATUS_UNEXPECTED_IO_ERROR;
 
-		if (!fp || !fp->filename)
-			kfree(name);
 		if (fp)
 			ksmbd_fd_put(work, fp);
 		smb2_set_err_rsp(work);
 		ksmbd_debug(SMB, "Error response: %x\n", rsp->hdr.Status);
 	}
 
+	kfree(name);
 	kfree(lc);
 
 	return 0;
@@ -3901,8 +3899,6 @@ int smb2_query_dir(struct ksmbd_work *work)
 		ksmbd_debug(SMB, "Search pattern is %s\n", srch_ptr);
 	}
 
-	ksmbd_debug(SMB, "Directory name is %s\n", dir_fp->filename);
-
 	if (srch_flag & SMB2_REOPEN || srch_flag & SMB2_RESTART_SCANS) {
 		ksmbd_debug(SMB, "Restart directory scan\n");
 		generic_file_llseek(dir_fp->filp, 0, SEEK_SET);
@@ -4396,9 +4392,9 @@ static int get_file_all_info(struct ksmbd_work *work,
 		return -EACCES;
 	}
 
-	filename = convert_to_nt_pathname(fp->filename);
-	if (!filename)
-		return -ENOMEM;
+	filename = convert_to_nt_pathname(work->tcon->share_conf, &fp->filp->f_path);
+	if (IS_ERR(filename))
+		return PTR_ERR(filename);
 
 	inode = file_inode(fp->filp);
 	generic_fillattr(file_mnt_user_ns(fp->filp), inode, &stat);
@@ -5689,8 +5685,7 @@ static int set_file_allocation_info(struct ksmbd_work *work,
 		size = i_size_read(inode);
 		rc = ksmbd_vfs_truncate(work, fp, alloc_blks * 512);
 		if (rc) {
-			pr_err("truncate failed! filename : %s, err %d\n",
-			       fp->filename, rc);
+			pr_err("truncate failed!, err %d\n", rc);
 			return rc;
 		}
 		if (size < alloc_blks * 512)
@@ -5720,12 +5715,10 @@ static int set_end_of_file_info(struct ksmbd_work *work, struct ksmbd_file *fp,
 	 * truncated range.
 	 */
 	if (inode->i_sb->s_magic != MSDOS_SUPER_MAGIC) {
-		ksmbd_debug(SMB, "filename : %s truncated to newsize %lld\n",
-			    fp->filename, newsize);
+		ksmbd_debug(SMB, "truncated to newsize %lld\n", newsize);
 		rc = ksmbd_vfs_truncate(work, fp, newsize);
 		if (rc) {
-			ksmbd_debug(SMB, "truncate failed! filename : %s err %d\n",
-				    fp->filename, rc);
+			ksmbd_debug(SMB, "truncate failed!, err %d\n", rc);
 			if (rc != -EAGAIN)
 				rc = -EBADF;
 			return rc;
diff --git a/fs/ksmbd/vfs.c b/fs/ksmbd/vfs.c
index a1ab0aaceba5..487617f729ec 100644
--- a/fs/ksmbd/vfs.c
+++ b/fs/ksmbd/vfs.c
@@ -397,8 +397,7 @@ int ksmbd_vfs_read(struct ksmbd_work *work, struct ksmbd_file *fp, size_t count,
 
 	nbytes = kernel_read(filp, rbuf, count, pos);
 	if (nbytes < 0) {
-		pr_err("smb read failed for (%s), err = %zd\n",
-		       fp->filename, nbytes);
+		pr_err("smb read failed, err = %zd\n", nbytes);
 		return nbytes;
 	}
 
@@ -874,8 +873,7 @@ int ksmbd_vfs_truncate(struct ksmbd_work *work,
 
 	err = vfs_truncate(&filp->f_path, size);
 	if (err)
-		pr_err("truncate failed for filename : %s err %d\n",
-		       fp->filename, err);
+		pr_err("truncate failed, err %d\n", err);
 	return err;
 }
 
diff --git a/fs/ksmbd/vfs_cache.c b/fs/ksmbd/vfs_cache.c
index 29c1db66bd0f..0974d2e972b9 100644
--- a/fs/ksmbd/vfs_cache.c
+++ b/fs/ksmbd/vfs_cache.c
@@ -328,7 +328,6 @@ static void __ksmbd_close_fd(struct ksmbd_file_table *ft, struct ksmbd_file *fp)
 		kfree(smb_lock);
 	}
 
-	kfree(fp->filename);
 	if (ksmbd_stream_fd(fp))
 		kfree(fp->stream.name);
 	kmem_cache_free(filp_cache, fp);
diff --git a/fs/ksmbd/vfs_cache.h b/fs/ksmbd/vfs_cache.h
index 36239ce31afd..fcb13413fa8d 100644
--- a/fs/ksmbd/vfs_cache.h
+++ b/fs/ksmbd/vfs_cache.h
@@ -62,7 +62,6 @@ struct ksmbd_inode {
 
 struct ksmbd_file {
 	struct file			*filp;
-	char				*filename;
 	u64				persistent_id;
 	u64				volatile_id;
 
-- 
2.25.1

Re: [PATCH 2/4] ksmbd: remove filename in ksmbd_file

[Sergey Senozhatsky]

On (22/03/01 08:48), Namjae Jeon wrote:
> -char *convert_to_nt_pathname(char *filename)
> +char *convert_to_nt_pathname(struct ksmbd_share_config *share,
> +			     struct path *path)
>  {
> -	char *ab_pathname;
> +	char *pathname, *ab_pathname, *nt_pathname = NULL;
> +	int share_path_len = strlen(share->path);
>  
> -	if (strlen(filename) == 0)
> -		filename = "\\";
> +	pathname = kmalloc(PATH_MAX, GFP_KERNEL);
> +	if (!pathname)
> +		return ERR_PTR(-EACCES);
>  
> -	ab_pathname = kstrdup(filename, GFP_KERNEL);
> -	if (!ab_pathname)
> -		return NULL;
> +	ab_pathname = d_path(path, pathname, PATH_MAX);
> +	if (IS_ERR(ab_pathname)) {
> +		nt_pathname = ERR_PTR(-EACCES);
> +		goto free_pathname;
> +	}
> +
> +	if (strncmp(ab_pathname, share->path, share_path_len)) {
> +		nt_pathname = ERR_PTR(-EACCES);
> +		goto free_pathname;
> +	}
> +
> +	nt_pathname = kzalloc(strlen(&ab_pathname[share_path_len]) + 1, GFP_KERNEL);
> +	if (!nt_pathname) {
> +		nt_pathname = ERR_PTR(-ENOMEM);
> +		goto free_pathname;
> +	}
> +	if (ab_pathname[share_path_len] == '\0')
> +		strcpy(nt_pathname, "/");
> +	strcat(nt_pathname, &ab_pathname[share_path_len]);
> +
> +	ksmbd_conv_path_to_windows(nt_pathname);
>  
> -	ksmbd_conv_path_to_windows(ab_pathname);
> -	return ab_pathname;
> +free_pathname:
> +	kfree(pathname);
> +	return nt_pathname;
>  }

convert_to_nt_pathname() can return NULL

> +	filename = convert_to_nt_pathname(work->tcon->share_conf, &fp->filp->f_path);
> +	if (IS_ERR(filename))
> +		return PTR_ERR(filename);

I don't think this will catch NULL nt_pathname return.

Re: [PATCH 2/4] ksmbd: remove filename in ksmbd_file

[Namjae Jeon]

2022-03-01 13:14 GMT+09:00, Sergey Senozhatsky <senozhatsky@chromium.org>:
> On (22/03/01 08:48), Namjae Jeon wrote:
>> -char *convert_to_nt_pathname(char *filename)
>> +char *convert_to_nt_pathname(struct ksmbd_share_config *share,
>> +			     struct path *path)
>>  {
>> -	char *ab_pathname;
>> +	char *pathname, *ab_pathname, *nt_pathname = NULL;
>> +	int share_path_len = strlen(share->path);
>>
>> -	if (strlen(filename) == 0)
>> -		filename = "\\";
>> +	pathname = kmalloc(PATH_MAX, GFP_KERNEL);
>> +	if (!pathname)
>> +		return ERR_PTR(-EACCES);
>>
>> -	ab_pathname = kstrdup(filename, GFP_KERNEL);
>> -	if (!ab_pathname)
>> -		return NULL;
>> +	ab_pathname = d_path(path, pathname, PATH_MAX);
>> +	if (IS_ERR(ab_pathname)) {
>> +		nt_pathname = ERR_PTR(-EACCES);
>> +		goto free_pathname;
>> +	}
>> +
>> +	if (strncmp(ab_pathname, share->path, share_path_len)) {
>> +		nt_pathname = ERR_PTR(-EACCES);
>> +		goto free_pathname;
>> +	}
>> +
>> +	nt_pathname = kzalloc(strlen(&ab_pathname[share_path_len]) + 1,
>> GFP_KERNEL);
>> +	if (!nt_pathname) {
>> +		nt_pathname = ERR_PTR(-ENOMEM);
>> +		goto free_pathname;
>> +	}
>> +	if (ab_pathname[share_path_len] == '\0')
>> +		strcpy(nt_pathname, "/");
>> +	strcat(nt_pathname, &ab_pathname[share_path_len]);
>> +
>> +	ksmbd_conv_path_to_windows(nt_pathname);
>>
>> -	ksmbd_conv_path_to_windows(ab_pathname);
>> -	return ab_pathname;
>> +free_pathname:
>> +	kfree(pathname);
>> +	return nt_pathname;
>>  }
>
> convert_to_nt_pathname() can return NULL
I can not find where this function return NULL.. Initializing NULL for
nt_pathname is unnecessary.

>
>> +	filename = convert_to_nt_pathname(work->tcon->share_conf,
>> &fp->filp->f_path);
>> +	if (IS_ERR(filename))
>> +		return PTR_ERR(filename);
>
> I don't think this will catch NULL nt_pathname return.
>

Re: [PATCH 2/4] ksmbd: remove filename in ksmbd_file

[Sergey Senozhatsky]

On (22/03/01 17:34), Namjae Jeon wrote:
> 2022-03-01 13:14 GMT+09:00, Sergey Senozhatsky <senozhatsky@chromium.org>:
> > On (22/03/01 08:48), Namjae Jeon wrote:
> >
> > convert_to_nt_pathname() can return NULL
> I can not find where this function return NULL..

Oh... Yes, you are right.

> Initializing NULL for nt_pathname is unnecessary.

Right.

[PATCH 3/4] ksmbd: increment reference count of parent fp

[Namjae Jeon]

Add missing increment reference count of parent fp in
ksmbd_lookup_fd_inode().

Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
---
 fs/ksmbd/smb2pdu.c   | 2 ++
 fs/ksmbd/vfs_cache.c | 1 +
 2 files changed, 3 insertions(+)

diff --git a/fs/ksmbd/smb2pdu.c b/fs/ksmbd/smb2pdu.c
index 3151ab7d7410..03c3733e54e4 100644
--- a/fs/ksmbd/smb2pdu.c
+++ b/fs/ksmbd/smb2pdu.c
@@ -5764,8 +5764,10 @@ static int set_rename_info(struct ksmbd_work *work, struct ksmbd_file *fp,
 	if (parent_fp) {
 		if (parent_fp->daccess & FILE_DELETE_LE) {
 			pr_err("parent dir is opened with delete access\n");
+			ksmbd_fd_put(work, parent_fp);
 			return -ESHARE;
 		}
+		ksmbd_fd_put(work, parent_fp);
 	}
 next:
 	return smb2_rename(work, fp, user_ns, rename_info,
diff --git a/fs/ksmbd/vfs_cache.c b/fs/ksmbd/vfs_cache.c
index 0974d2e972b9..c4d59d2735f0 100644
--- a/fs/ksmbd/vfs_cache.c
+++ b/fs/ksmbd/vfs_cache.c
@@ -496,6 +496,7 @@ struct ksmbd_file *ksmbd_lookup_fd_inode(struct inode *inode)
 	list_for_each_entry(lfp, &ci->m_fp_list, node) {
 		if (inode == file_inode(lfp->filp)) {
 			atomic_dec(&ci->m_count);
+			lfp = ksmbd_fp_get(lfp);
 			read_unlock(&ci->m_lock);
 			return lfp;
 		}
-- 
2.25.1

Re: [PATCH 3/4] ksmbd: increment reference count of parent fp

[Sergey Senozhatsky]

On (22/03/01 08:48), Namjae Jeon wrote:
> diff --git a/fs/ksmbd/smb2pdu.c b/fs/ksmbd/smb2pdu.c
> index 3151ab7d7410..03c3733e54e4 100644
> --- a/fs/ksmbd/smb2pdu.c
> +++ b/fs/ksmbd/smb2pdu.c
> @@ -5764,8 +5764,10 @@ static int set_rename_info(struct ksmbd_work *work, struct ksmbd_file *fp,
>  	if (parent_fp) {
>  		if (parent_fp->daccess & FILE_DELETE_LE) {
>  			pr_err("parent dir is opened with delete access\n");
> +			ksmbd_fd_put(work, parent_fp);
>  			return -ESHARE;
>  		}
> +		ksmbd_fd_put(work, parent_fp);
>  	}

And also in ksmbd_validate_entry_in_use()?

>  next:
>  	return smb2_rename(work, fp, user_ns, rename_info,
> diff --git a/fs/ksmbd/vfs_cache.c b/fs/ksmbd/vfs_cache.c
> index 0974d2e972b9..c4d59d2735f0 100644
> --- a/fs/ksmbd/vfs_cache.c
> +++ b/fs/ksmbd/vfs_cache.c
> @@ -496,6 +496,7 @@ struct ksmbd_file *ksmbd_lookup_fd_inode(struct inode *inode)
>  	list_for_each_entry(lfp, &ci->m_fp_list, node) {
>  		if (inode == file_inode(lfp->filp)) {
>  			atomic_dec(&ci->m_count);
> +			lfp = ksmbd_fp_get(lfp);
>  			read_unlock(&ci->m_lock);
>  			return lfp;
>  		}
> -- 
> 2.25.1
> 

Re: [PATCH 3/4] ksmbd: increment reference count of parent fp

[Namjae Jeon]

2022-03-01 13:21 GMT+09:00, Sergey Senozhatsky <senozhatsky@chromium.org>:
> On (22/03/01 08:48), Namjae Jeon wrote:
>> diff --git a/fs/ksmbd/smb2pdu.c b/fs/ksmbd/smb2pdu.c
>> index 3151ab7d7410..03c3733e54e4 100644
>> --- a/fs/ksmbd/smb2pdu.c
>> +++ b/fs/ksmbd/smb2pdu.c
>> @@ -5764,8 +5764,10 @@ static int set_rename_info(struct ksmbd_work *work,
>> struct ksmbd_file *fp,
>>  	if (parent_fp) {
>>  		if (parent_fp->daccess & FILE_DELETE_LE) {
>>  			pr_err("parent dir is opened with delete access\n");
>> +			ksmbd_fd_put(work, parent_fp);
>>  			return -ESHARE;
>>  		}
>> +		ksmbd_fd_put(work, parent_fp);
>>  	}
>
> And also in ksmbd_validate_entry_in_use()?
ksmbd_validate_entry_in_use() is removed in 4/4 patch.
I need to change the order of the patches to avoid confusion.

Thanks!
>
>>  next:
>>  	return smb2_rename(work, fp, user_ns, rename_info,
>> diff --git a/fs/ksmbd/vfs_cache.c b/fs/ksmbd/vfs_cache.c
>> index 0974d2e972b9..c4d59d2735f0 100644
>> --- a/fs/ksmbd/vfs_cache.c
>> +++ b/fs/ksmbd/vfs_cache.c
>> @@ -496,6 +496,7 @@ struct ksmbd_file *ksmbd_lookup_fd_inode(struct inode
>> *inode)
>>  	list_for_each_entry(lfp, &ci->m_fp_list, node) {
>>  		if (inode == file_inode(lfp->filp)) {
>>  			atomic_dec(&ci->m_count);
>> +			lfp = ksmbd_fp_get(lfp);
>>  			read_unlock(&ci->m_lock);
>>  			return lfp;
>>  		}
>> --
>> 2.25.1
>>
>

[PATCH v3 4/4] ksmbd: fix racy issue from using ->d_parent and ->d_name

[Namjae Jeon]

Al pointed out that ksmbd has racy issue from using ->d_parent and ->d_name
in ksmbd_vfs_unlink and smb2_vfs_rename(). add dget_parent() in
ksmbd_vfs_unlink() and use take_dentry_name_snapshot() to check
underlying rename for lookup. Introduce vfs_path_parent_lookup helper
to avoid out of share access and export vfs functions like the following
ones to use vfs_path_parent_lookup().
 - __lookup_hash().
 - getname_kernel() and putname().

vfs_path_parent_lookup() is used for parent lookup of destination file
using absolute pathname given from FILE_RENAME_INFORMATION request.

Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
---
 v3:
   - use dget_parent + take_dentry_name_snapshot() to check stability of source
     rename in smb2_vfs_rename().
 v2:
   - add filename_lock to avoid racy issue from fp->filename. (Sergey Senozhatsky)
   - fix warning: variable 'old_dentry' is used uninitialized (kernel
     test robot)

 fs/ksmbd/smb2pdu.c    | 105 ++----------------
 fs/ksmbd/vfs.c        | 253 +++++++++++++++++++-----------------------
 fs/ksmbd/vfs.h        |   7 +-
 fs/ksmbd/vfs_cache.c  |   5 +-
 fs/namei.c            |  41 ++++++-
 include/linux/namei.h |   4 +
 6 files changed, 167 insertions(+), 248 deletions(-)

diff --git a/fs/ksmbd/smb2pdu.c b/fs/ksmbd/smb2pdu.c
index 03c3733e54e4..bcb98109bac9 100644
--- a/fs/ksmbd/smb2pdu.c
+++ b/fs/ksmbd/smb2pdu.c
@@ -5365,44 +5365,19 @@ int smb2_echo(struct ksmbd_work *work)
 
 static int smb2_rename(struct ksmbd_work *work,
 		       struct ksmbd_file *fp,
-		       struct user_namespace *user_ns,
 		       struct smb2_file_rename_info *file_info,
 		       struct nls_table *local_nls)
 {
 	struct ksmbd_share_config *share = fp->tcon->share_conf;
-	char *new_name = NULL, *abs_oldname = NULL, *old_name = NULL;
-	char *pathname = NULL;
-	struct path path;
-	bool file_present = true;
-	int rc;
+	char *new_name = NULL;
+	int rc, flags = 0;
 
 	ksmbd_debug(SMB, "setting FILE_RENAME_INFO\n");
-	pathname = kmalloc(PATH_MAX, GFP_KERNEL);
-	if (!pathname)
-		return -ENOMEM;
-
-	abs_oldname = d_path(&fp->filp->f_path, pathname, PATH_MAX);
-	if (IS_ERR(abs_oldname)) {
-		rc = -EINVAL;
-		goto out;
-	}
-	old_name = strrchr(abs_oldname, '/');
-	if (old_name && old_name[1] != '\0') {
-		old_name++;
-	} else {
-		ksmbd_debug(SMB, "can't get last component in path %s\n",
-			    abs_oldname);
-		rc = -ENOENT;
-		goto out;
-	}
-
 	new_name = smb2_get_name(file_info->FileName,
 				 le32_to_cpu(file_info->FileNameLength),
 				 local_nls);
-	if (IS_ERR(new_name)) {
-		rc = PTR_ERR(new_name);
-		goto out;
-	}
+	if (IS_ERR(new_name))
+		return PTR_ERR(new_name);
 
 	if (strchr(new_name, ':')) {
 		int s_type;
@@ -5428,7 +5403,7 @@ static int smb2_rename(struct ksmbd_work *work,
 		if (rc)
 			goto out;
 
-		rc = ksmbd_vfs_setxattr(user_ns,
+		rc = ksmbd_vfs_setxattr(file_mnt_user_ns(fp->filp),
 					fp->filp->f_path.dentry,
 					xattr_stream_name,
 					NULL, 0, 0);
@@ -5443,47 +5418,18 @@ static int smb2_rename(struct ksmbd_work *work,
 	}
 
 	ksmbd_debug(SMB, "new name %s\n", new_name);
-	rc = ksmbd_vfs_kern_path(work, new_name, LOOKUP_NO_SYMLINKS, &path, 1);
-	if (rc) {
-		if (rc != -ENOENT)
-			goto out;
-		file_present = false;
-	} else {
-		path_put(&path);
-	}
-
 	if (ksmbd_share_veto_filename(share, new_name)) {
 		rc = -ENOENT;
 		ksmbd_debug(SMB, "Can't rename vetoed file: %s\n", new_name);
 		goto out;
 	}
 
-	if (file_info->ReplaceIfExists) {
-		if (file_present) {
-			rc = ksmbd_vfs_remove_file(work, new_name);
-			if (rc) {
-				if (rc != -ENOTEMPTY)
-					rc = -EINVAL;
-				ksmbd_debug(SMB, "cannot delete %s, rc %d\n",
-					    new_name, rc);
-				goto out;
-			}
-		}
-	} else {
-		if (file_present &&
-		    strncmp(old_name, path.dentry->d_name.name, strlen(old_name))) {
-			rc = -EEXIST;
-			ksmbd_debug(SMB,
-				    "cannot rename already existing file\n");
-			goto out;
-		}
-	}
+	if (!file_info->ReplaceIfExists)
+		flags = RENAME_NOREPLACE;
 
-	rc = ksmbd_vfs_fp_rename(work, fp, new_name);
+	rc = ksmbd_vfs_rename(work, &fp->filp->f_path, new_name, flags);
 out:
-	kfree(pathname);
-	if (!IS_ERR(new_name))
-		kfree(new_name);
+	kfree(new_name);
 	return rc;
 }
 
@@ -5731,12 +5677,6 @@ static int set_rename_info(struct ksmbd_work *work, struct ksmbd_file *fp,
 			   struct smb2_file_rename_info *rename_info,
 			   unsigned int buf_len)
 {
-	struct user_namespace *user_ns;
-	struct ksmbd_file *parent_fp;
-	struct dentry *parent;
-	struct dentry *dentry = fp->filp->f_path.dentry;
-	int ret;
-
 	if (!(fp->daccess & FILE_DELETE_LE)) {
 		pr_err("no right to delete : 0x%x\n", fp->daccess);
 		return -EACCES;
@@ -5746,32 +5686,7 @@ static int set_rename_info(struct ksmbd_work *work, struct ksmbd_file *fp,
 			le32_to_cpu(rename_info->FileNameLength))
 		return -EINVAL;
 
-	user_ns = file_mnt_user_ns(fp->filp);
-	if (ksmbd_stream_fd(fp))
-		goto next;
-
-	parent = dget_parent(dentry);
-	ret = ksmbd_vfs_lock_parent(user_ns, parent, dentry);
-	if (ret) {
-		dput(parent);
-		return ret;
-	}
-
-	parent_fp = ksmbd_lookup_fd_inode(d_inode(parent));
-	inode_unlock(d_inode(parent));
-	dput(parent);
-
-	if (parent_fp) {
-		if (parent_fp->daccess & FILE_DELETE_LE) {
-			pr_err("parent dir is opened with delete access\n");
-			ksmbd_fd_put(work, parent_fp);
-			return -ESHARE;
-		}
-		ksmbd_fd_put(work, parent_fp);
-	}
-next:
-	return smb2_rename(work, fp, user_ns, rename_info,
-			   work->sess->conn->local_nls);
+	return smb2_rename(work, fp, rename_info, work->sess->conn->local_nls);
 }
 
 static int set_file_disposition_info(struct ksmbd_file *fp,
diff --git a/fs/ksmbd/vfs.c b/fs/ksmbd/vfs.c
index 487617f729ec..0b92092f3e8a 100644
--- a/fs/ksmbd/vfs.c
+++ b/fs/ksmbd/vfs.c
@@ -35,19 +35,6 @@
 #include "mgmt/user_session.h"
 #include "mgmt/user_config.h"
 
-static char *extract_last_component(char *path)
-{
-	char *p = strrchr(path, '/');
-
-	if (p && p[1] != '\0') {
-		*p = '\0';
-		p++;
-	} else {
-		p = NULL;
-	}
-	return p;
-}
-
 static void ksmbd_vfs_inherit_owner(struct ksmbd_work *work,
 				    struct inode *parent_inode,
 				    struct inode *inode)
@@ -72,11 +59,14 @@ int ksmbd_vfs_lock_parent(struct user_namespace *user_ns, struct dentry *parent,
 			  struct dentry *child)
 {
 	struct dentry *dentry;
+	struct name_snapshot name;
 	int ret = 0;
 
 	inode_lock_nested(d_inode(parent), I_MUTEX_PARENT);
-	dentry = lookup_one(user_ns, child->d_name.name, parent,
-			    child->d_name.len);
+	take_dentry_name_snapshot(&name, child);
+	dentry = lookup_one(user_ns, name.name.name, parent,
+			    name.name.len);
+	release_dentry_name_snapshot(&name);
 	if (IS_ERR(dentry)) {
 		ret = PTR_ERR(dentry);
 		goto out_err;
@@ -689,149 +679,130 @@ int ksmbd_vfs_link(struct ksmbd_work *work, const char *oldname,
 	return err;
 }
 
-static int ksmbd_validate_entry_in_use(struct dentry *src_dent)
+int ksmbd_vfs_rename(struct ksmbd_work *work, struct path *old_path,
+		     char *newname, int flags)
 {
-	struct dentry *dst_dent;
-
-	spin_lock(&src_dent->d_lock);
-	list_for_each_entry(dst_dent, &src_dent->d_subdirs, d_child) {
-		struct ksmbd_file *child_fp;
+	struct dentry *old_parent, *old_dentry, *new_dentry, *trap;
+	struct dentry *old_child = old_path->dentry;
+	struct path new_path;
+	struct qstr new_last;
+	struct renamedata rd;
+	struct filename *to;
+	struct ksmbd_share_config *share_conf = work->tcon->share_conf;
+	struct ksmbd_file *parent_fp;
+	struct name_snapshot name;
+	int new_type;
+	int err, lookup_flags = LOOKUP_NO_SYMLINKS;
 
-		if (d_really_is_negative(dst_dent))
-			continue;
+	if (ksmbd_override_fsids(work))
+		return -ENOMEM;
 
-		child_fp = ksmbd_lookup_fd_inode(d_inode(dst_dent));
-		if (child_fp) {
-			spin_unlock(&src_dent->d_lock);
-			ksmbd_debug(VFS, "Forbid rename, sub file/dir is in use\n");
-			return -EACCES;
-		}
+	to = getname_kernel(newname);
+	if (IS_ERR(to)) {
+		err = PTR_ERR(to);
+		goto revert_fsids;
 	}
-	spin_unlock(&src_dent->d_lock);
-
-	return 0;
-}
 
-static int __ksmbd_vfs_rename(struct ksmbd_work *work,
-			      struct user_namespace *src_user_ns,
-			      struct dentry *src_dent_parent,
-			      struct dentry *src_dent,
-			      struct user_namespace *dst_user_ns,
-			      struct dentry *dst_dent_parent,
-			      struct dentry *trap_dent,
-			      char *dst_name)
-{
-	struct dentry *dst_dent;
-	int err;
+	old_parent = dget_parent(old_child);
+retry:
+	err = vfs_path_parent_lookup(to, lookup_flags | LOOKUP_BENEATH,
+				     &new_path, &new_last, &new_type,
+				     &share_conf->vfs_path);
+	if (err)
+		goto out1;
 
-	if (!work->tcon->posix_extensions) {
-		err = ksmbd_validate_entry_in_use(src_dent);
-		if (err)
-			return err;
+	if (d_is_symlink(new_path.dentry)) {
+		err = -EACCES;
+		goto out2;
 	}
 
-	if (d_really_is_negative(src_dent_parent))
-		return -ENOENT;
-	if (d_really_is_negative(dst_dent_parent))
-		return -ENOENT;
-	if (d_really_is_negative(src_dent))
-		return -ENOENT;
-	if (src_dent == trap_dent)
-		return -EINVAL;
+	if (old_path->mnt != new_path.mnt) {
+		err = -EXDEV;
+		goto out2;
+	}
 
-	if (ksmbd_override_fsids(work))
-		return -ENOMEM;
+	trap = lock_rename(old_parent, new_path.dentry);
+	take_dentry_name_snapshot(&name, old_child);
+	old_dentry = lookup_one(mnt_user_ns(old_path->mnt), name.name.name,
+				old_parent, name.name.len);
+	release_dentry_name_snapshot(&name);
+	if (IS_ERR(old_dentry)) {
+		err = PTR_ERR(old_dentry);
+		goto out3;
+	}
 
-	dst_dent = lookup_one(dst_user_ns, dst_name, dst_dent_parent,
-			      strlen(dst_name));
-	err = PTR_ERR(dst_dent);
-	if (IS_ERR(dst_dent)) {
-		pr_err("lookup failed %s [%d]\n", dst_name, err);
-		goto out;
+	if (old_dentry != old_child) {
+		err = -ESTALE;
+		dput(old_dentry);
+		goto out4;
 	}
 
-	err = -ENOTEMPTY;
-	if (dst_dent != trap_dent && !d_really_is_positive(dst_dent)) {
-		struct renamedata rd = {
-			.old_mnt_userns	= src_user_ns,
-			.old_dir	= d_inode(src_dent_parent),
-			.old_dentry	= src_dent,
-			.new_mnt_userns	= dst_user_ns,
-			.new_dir	= d_inode(dst_dent_parent),
-			.new_dentry	= dst_dent,
-		};
-		err = vfs_rename(&rd);
+	new_dentry = __lookup_hash(&new_last, new_path.dentry,
+				   lookup_flags | LOOKUP_RENAME_TARGET);
+	if (IS_ERR(new_dentry)) {
+		err = PTR_ERR(new_dentry);
+		goto out4;
 	}
-	if (err)
-		pr_err("vfs_rename failed err %d\n", err);
-	if (dst_dent)
-		dput(dst_dent);
-out:
-	ksmbd_revert_fsids(work);
-	return err;
-}
 
-int ksmbd_vfs_fp_rename(struct ksmbd_work *work, struct ksmbd_file *fp,
-			char *newname)
-{
-	struct user_namespace *user_ns;
-	struct path dst_path;
-	struct dentry *src_dent_parent, *dst_dent_parent;
-	struct dentry *src_dent, *trap_dent, *src_child;
-	char *dst_name;
-	int err;
+	if (d_is_symlink(new_dentry)) {
+		err = -EACCES;
+		goto out5;
+	}
 
-	dst_name = extract_last_component(newname);
-	if (!dst_name) {
-		dst_name = newname;
-		newname = "";
+	if ((flags & RENAME_NOREPLACE) && d_is_positive(new_dentry)) {
+		err = -EEXIST;
+		goto out5;
 	}
 
-	src_dent_parent = dget_parent(fp->filp->f_path.dentry);
-	src_dent = fp->filp->f_path.dentry;
+	if (old_dentry == trap) {
+		err = -EINVAL;
+		goto out5;
+	}
 
-	err = ksmbd_vfs_kern_path(work, newname,
-				  LOOKUP_NO_SYMLINKS | LOOKUP_DIRECTORY,
-				  &dst_path, false);
-	if (err) {
-		ksmbd_debug(VFS, "Cannot get path for %s [%d]\n", newname, err);
-		goto out;
+	if (new_dentry == trap) {
+		err = -ENOTEMPTY;
+		goto out5;
 	}
-	dst_dent_parent = dst_path.dentry;
 
-	trap_dent = lock_rename(src_dent_parent, dst_dent_parent);
-	dget(src_dent);
-	dget(dst_dent_parent);
-	user_ns = file_mnt_user_ns(fp->filp);
-	src_child = lookup_one(user_ns, src_dent->d_name.name, src_dent_parent,
-			       src_dent->d_name.len);
-	if (IS_ERR(src_child)) {
-		err = PTR_ERR(src_child);
-		goto out_lock;
+	parent_fp = ksmbd_lookup_fd_inode(old_parent->d_inode);
+	if (parent_fp) {
+		if (parent_fp->daccess & FILE_DELETE_LE) {
+			pr_err("parent dir is opened with delete access\n");
+			err = -ESHARE;
+			ksmbd_fd_put(work, parent_fp);
+			goto out5;
+		}
+		ksmbd_fd_put(work, parent_fp);
 	}
 
-	if (src_child != src_dent) {
-		err = -ESTALE;
-		dput(src_child);
-		goto out_lock;
-	}
-	dput(src_child);
-
-	err = __ksmbd_vfs_rename(work,
-				 user_ns,
-				 src_dent_parent,
-				 src_dent,
-				 mnt_user_ns(dst_path.mnt),
-				 dst_dent_parent,
-				 trap_dent,
-				 dst_name);
-out_lock:
-	dput(src_dent);
-	dput(dst_dent_parent);
-	unlock_rename(src_dent_parent, dst_dent_parent);
-	path_put(&dst_path);
-out:
-	dput(src_dent_parent);
+	rd.old_mnt_userns	= mnt_user_ns(old_path->mnt),
+	rd.old_dir		= old_parent->d_inode,
+	rd.old_dentry		= old_dentry,
+	rd.new_mnt_userns	= mnt_user_ns(new_path.mnt),
+	rd.new_dir		= new_path.dentry->d_inode,
+	rd.new_dentry		= new_dentry,
+	rd.flags		= flags,
+	err = vfs_rename(&rd);
+	if (err)
+		ksmbd_debug(VFS, "vfs_rename failed err %d\n", err);
+out5:
+	dput(new_dentry);
+out4:
+	dput(old_dentry);
+out3:
+	unlock_rename(old_parent, new_path.dentry);
+out2:
+	path_put(&new_path);
+
+	if (retry_estale(err, lookup_flags)) {
+		lookup_flags |= LOOKUP_REVAL;
+		goto retry;
+	}
+out1:
+	putname(to);
+	dput(old_parent);
+revert_fsids:
+	ksmbd_revert_fsids(work);
 	return err;
 }
 
@@ -1080,14 +1051,16 @@ int ksmbd_vfs_remove_xattr(struct user_namespace *user_ns,
 	return vfs_removexattr(user_ns, dentry, attr_name);
 }
 
-int ksmbd_vfs_unlink(struct user_namespace *user_ns,
-		     struct dentry *dir, struct dentry *dentry)
+int ksmbd_vfs_unlink(struct file *filp)
 {
 	int err = 0;
+	struct dentry *dir, *dentry = filp->f_path.dentry;
+	struct user_namespace *user_ns = file_mnt_user_ns(filp);
 
+	dir = dget_parent(dentry);
 	err = ksmbd_vfs_lock_parent(user_ns, dir, dentry);
 	if (err)
-		return err;
+		goto out;
 	dget(dentry);
 
 	if (S_ISDIR(d_inode(dentry)->i_mode))
@@ -1099,6 +1072,8 @@ int ksmbd_vfs_unlink(struct user_namespace *user_ns,
 	inode_unlock(d_inode(dir));
 	if (err)
 		ksmbd_debug(VFS, "failed to delete, err %d\n", err);
+out:
+	dput(dir);
 
 	return err;
 }
diff --git a/fs/ksmbd/vfs.h b/fs/ksmbd/vfs.h
index 8c37aaf936ab..5b8070774aab 100644
--- a/fs/ksmbd/vfs.h
+++ b/fs/ksmbd/vfs.h
@@ -86,8 +86,8 @@ int ksmbd_vfs_remove_file(struct ksmbd_work *work, char *name);
 int ksmbd_vfs_link(struct ksmbd_work *work,
 		   const char *oldname, const char *newname);
 int ksmbd_vfs_getattr(struct path *path, struct kstat *stat);
-int ksmbd_vfs_fp_rename(struct ksmbd_work *work, struct ksmbd_file *fp,
-			char *newname);
+int ksmbd_vfs_rename(struct ksmbd_work *work, struct path *old_path,
+		     char *newname, int flags);
 int ksmbd_vfs_truncate(struct ksmbd_work *work,
 		       struct ksmbd_file *fp, loff_t size);
 struct srv_copychunk;
@@ -129,8 +129,7 @@ struct file_allocated_range_buffer;
 int ksmbd_vfs_fqar_lseek(struct ksmbd_file *fp, loff_t start, loff_t length,
 			 struct file_allocated_range_buffer *ranges,
 			 unsigned int in_count, unsigned int *out_count);
-int ksmbd_vfs_unlink(struct user_namespace *user_ns,
-		     struct dentry *dir, struct dentry *dentry);
+int ksmbd_vfs_unlink(struct file *filp);
 void *ksmbd_vfs_init_kstat(char **p, struct ksmbd_kstat *ksmbd_kstat);
 int ksmbd_vfs_fill_dentry_attrs(struct ksmbd_work *work,
 				struct user_namespace *user_ns,
diff --git a/fs/ksmbd/vfs_cache.c b/fs/ksmbd/vfs_cache.c
index c4d59d2735f0..df600eb04552 100644
--- a/fs/ksmbd/vfs_cache.c
+++ b/fs/ksmbd/vfs_cache.c
@@ -243,7 +243,6 @@ void ksmbd_release_inode_hash(void)
 
 static void __ksmbd_inode_close(struct ksmbd_file *fp)
 {
-	struct dentry *dir, *dentry;
 	struct ksmbd_inode *ci = fp->f_ci;
 	int err;
 	struct file *filp;
@@ -262,11 +261,9 @@ static void __ksmbd_inode_close(struct ksmbd_file *fp)
 	if (atomic_dec_and_test(&ci->m_count)) {
 		write_lock(&ci->m_lock);
 		if (ci->m_flags & (S_DEL_ON_CLS | S_DEL_PENDING)) {
-			dentry = filp->f_path.dentry;
-			dir = dentry->d_parent;
 			ci->m_flags &= ~(S_DEL_ON_CLS | S_DEL_PENDING);
 			write_unlock(&ci->m_lock);
-			ksmbd_vfs_unlink(file_mnt_user_ns(filp), dir, dentry);
+			ksmbd_vfs_unlink(filp);
 			write_lock(&ci->m_lock);
 		}
 		write_unlock(&ci->m_lock);
diff --git a/fs/namei.c b/fs/namei.c
index 3f1829b3ab5b..e882156877f6 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -252,6 +252,7 @@ getname_kernel(const char * filename)
 
 	return result;
 }
+EXPORT_SYMBOL(getname_kernel);
 
 void putname(struct filename *name)
 {
@@ -269,6 +270,7 @@ void putname(struct filename *name)
 	} else
 		__putname(name);
 }
+EXPORT_SYMBOL(putname);
 
 /**
  * check_acl - perform ACL permission checking
@@ -1587,8 +1589,8 @@ static struct dentry *lookup_dcache(const struct qstr *name,
  * when directory is guaranteed to have no in-lookup children
  * at all.
  */
-static struct dentry *__lookup_hash(const struct qstr *name,
-		struct dentry *base, unsigned int flags)
+struct dentry *__lookup_hash(const struct qstr *name, struct dentry *base,
+			     unsigned int flags)
 {
 	struct dentry *dentry = lookup_dcache(name, base, flags);
 	struct dentry *old;
@@ -1612,6 +1614,7 @@ static struct dentry *__lookup_hash(const struct qstr *name,
 	}
 	return dentry;
 }
+EXPORT_SYMBOL(__lookup_hash);
 
 static struct dentry *lookup_fast(struct nameidata *nd,
 				  struct inode **inode,
@@ -2556,16 +2559,17 @@ static int path_parentat(struct nameidata *nd, unsigned flags,
 }
 
 /* Note: this does not consume "name" */
-static int filename_parentat(int dfd, struct filename *name,
-			     unsigned int flags, struct path *parent,
-			     struct qstr *last, int *type)
+static int __filename_parentat(int dfd, struct filename *name,
+			       unsigned int flags, struct path *parent,
+			       struct qstr *last, int *type,
+			       const struct path *root)
 {
 	int retval;
 	struct nameidata nd;
 
 	if (IS_ERR(name))
 		return PTR_ERR(name);
-	set_nameidata(&nd, dfd, name, NULL);
+	set_nameidata(&nd, dfd, name, root);
 	retval = path_parentat(&nd, flags | LOOKUP_RCU, parent);
 	if (unlikely(retval == -ECHILD))
 		retval = path_parentat(&nd, flags, parent);
@@ -2580,6 +2584,12 @@ static int filename_parentat(int dfd, struct filename *name,
 	return retval;
 }
 
+int filename_parentat(int dfd, struct filename *name, unsigned int flags,
+		      struct path *parent, struct qstr *last, int *type)
+{
+	return __filename_parentat(dfd, name, flags, parent, last, type, NULL);
+}
+
 /* does lookup, returns the object with parent locked */
 static struct dentry *__kern_path_locked(struct filename *name, struct path *path)
 {
@@ -2623,6 +2633,25 @@ int kern_path(const char *name, unsigned int flags, struct path *path)
 }
 EXPORT_SYMBOL(kern_path);
 
+/**
+ * vfs_path_parent_lookup - lookup a parent path relative to a dentry-vfsmount pair
+ * @dentry:  pointer to dentry of the base directory
+ * @mnt: pointer to vfs mount of the base directory
+ * @filename: filename structure
+ * @flags: lookup flags
+ * @parent: pointer to struct path to fill
+ * @last: last component
+ * @type: type of the last component
+ */
+int vfs_path_parent_lookup(struct filename *filename, unsigned int flags,
+			   struct path *parent, struct qstr *last, int *type,
+			   const struct path *root)
+{
+	return  __filename_parentat(AT_FDCWD, filename, flags, parent, last,
+				    type, root);
+}
+EXPORT_SYMBOL(vfs_path_parent_lookup);
+
 /**
  * vfs_path_lookup - lookup a file path relative to a dentry-vfsmount pair
  * @dentry:  pointer to dentry of the base directory
diff --git a/include/linux/namei.h b/include/linux/namei.h
index 4858c3cdf7c6..439b2a6767ae 100644
--- a/include/linux/namei.h
+++ b/include/linux/namei.h
@@ -57,12 +57,16 @@ static inline int user_path_at(int dfd, const char __user *name, unsigned flags,
 	return user_path_at_empty(dfd, name, flags, path, NULL);
 }
 
+struct dentry *__lookup_hash(const struct qstr *name, struct dentry *base,
+			     unsigned int flags);
 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 *);
+int vfs_path_parent_lookup(struct filename *, unsigned int, struct path *,\
+			   struct qstr *, int *, const struct path *);
 int vfs_path_lookup(struct dentry *, struct vfsmount *, const char *,
 		    unsigned int, struct path *);
 
-- 
2.25.1