Merge tag '6.4-rc-ksmbd-server-fixes' of git://git.samba.org/ksmbd

Pull ksmbd server updates from Steve French:

 - SMB3.1.1 negotiate context fixes and cleanup

 - new lock_rename_child VFS helper

 - ksmbd fix to avoid unlink race and to use the new VFS helper to avoid
   rename race

* tag '6.4-rc-ksmbd-server-fixes' of git://git.samba.org/ksmbd:
  ksmbd: fix racy issue from using ->d_parent and ->d_name
  ksmbd: remove unused compression negotiate ctx packing
  ksmbd: avoid duplicate negotiate ctx offset increments
  ksmbd: set NegotiateContextCount once instead of every inc
  fs: introduce lock_rename_child() helper
  ksmbd: remove internal.h include

fs/internal.h

@@ -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.h

@@ -71,9 +71,7 @@ struct ksmbd_kstat {
 	__le32			file_attributes;
 };
 
-int ksmbd_vfs_lock_parent(struct mnt_idmap *idmap, struct dentry *parent,
-			  struct dentry *child);
-int ksmbd_vfs_may_delete(struct mnt_idmap *idmap, struct dentry *dentry);
+int ksmbd_vfs_lock_parent(struct dentry *parent, struct dentry *child);
 int ksmbd_vfs_query_maximal_access(struct mnt_idmap *idmap,
 				   struct dentry *dentry, __le32 *daccess);
 int ksmbd_vfs_create(struct ksmbd_work *work, const char *name, umode_t mode);
@@ -84,12 +82,12 @@ int ksmbd_vfs_write(struct ksmbd_work *work, struct ksmbd_file *fp,
 		    char *buf, size_t count, loff_t *pos, bool sync,
 		    ssize_t *written);
 int ksmbd_vfs_fsync(struct ksmbd_work *work, u64 fid, u64 p_id);
-int ksmbd_vfs_remove_file(struct ksmbd_work *work, char *name);
+int ksmbd_vfs_remove_file(struct ksmbd_work *work, const struct path *path);
 int ksmbd_vfs_link(struct ksmbd_work *work,
 		   const char *oldname, const char *newname);
 int ksmbd_vfs_getattr(const 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, const 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;
@@ -116,8 +114,8 @@ int ksmbd_vfs_xattr_stream_name(char *stream_name, char **xattr_stream_name,
 				size_t *xattr_stream_name_size, int s_type);
 int ksmbd_vfs_remove_xattr(struct mnt_idmap *idmap,
 			   struct dentry *dentry, char *attr_name);
-int ksmbd_vfs_kern_path(struct ksmbd_work *work,
-			char *name, unsigned int flags, struct path *path,
+int ksmbd_vfs_kern_path_locked(struct ksmbd_work *work, char *name,
+			       unsigned int flags, struct path *path,
 			       bool caseless);
 struct dentry *ksmbd_vfs_kern_path_create(struct ksmbd_work *work,
 					  const char *name,
@@ -131,8 +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 mnt_idmap *idmap, 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 mnt_idmap *idmap,

fs/ksmbd/vfs_cache.c

@@ -244,7 +244,6 @@ 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;
@@ -263,11 +262,9 @@ 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_idmap(filp), dir, dentry);
+			ksmbd_vfs_unlink(filp);
 			write_lock(&ci->m_lock);
 		}
 		write_unlock(&ci->m_lock);

fs/namei.c

@@ -254,6 +254,7 @@ getname_kernel(const char * filename)
 
 	return result;
 }
+EXPORT_SYMBOL(getname_kernel);
 
 void putname(struct filename *name)
 {
@@ -271,6 +272,7 @@ void putname(struct filename *name)
 	} else
 		__putname(name);
 }
+EXPORT_SYMBOL(putname);
 
 /**
  * check_acl - perform ACL permission checking
@@ -1581,8 +1583,9 @@ 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_one_qstr_excl(const struct qstr *name,
+				    struct dentry *base,
+				    unsigned int flags)
 {
 	struct dentry *dentry = lookup_dcache(name, base, flags);
 	struct dentry *old;
@@ -1606,6 +1609,7 @@ static struct dentry *__lookup_hash(const struct qstr *name,
 	}
 	return dentry;
 }
+EXPORT_SYMBOL(lookup_one_qstr_excl);
 
 static struct dentry *lookup_fast(struct nameidata *nd)
 {
@@ -2532,16 +2536,17 @@ static int path_parentat(struct nameidata *nd, unsigned flags,
 }
 
 /* Note: this does not consume "name" */
-static int filename_parentat(int dfd, struct filename *name,
+static int __filename_parentat(int dfd, struct filename *name,
 			       unsigned int flags, struct path *parent,
-			     struct qstr *last, int *type)
+			       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);
@@ -2556,6 +2561,13 @@ static int filename_parentat(int dfd, struct filename *name,
 	return retval;
 }
 
+static 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)
 {
@@ -2571,7 +2583,7 @@ static struct dentry *__kern_path_locked(struct filename *name, struct path *pat
 		return ERR_PTR(-EINVAL);
 	}
 	inode_lock_nested(path->dentry->d_inode, I_MUTEX_PARENT);
-	d = __lookup_hash(&last, path->dentry, 0);
+	d = lookup_one_qstr_excl(&last, path->dentry, 0);
 	if (IS_ERR(d)) {
 		inode_unlock(path->dentry->d_inode);
 		path_put(path);
@@ -2599,6 +2611,24 @@ 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
+ * @filename: filename structure
+ * @flags: lookup flags
+ * @parent: pointer to struct path to fill
+ * @last: last component
+ * @type: type of the last component
+ * @root: pointer to struct path of the base directory
+ */
+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
@@ -2980,20 +3010,10 @@ 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 +3032,64 @@ 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);
@@ -3806,7 +3882,8 @@ static struct dentry *filename_create(int dfd, struct filename *name,
 	if (last.name[last.len] && !want_dir)
 		create_flags = 0;
 	inode_lock_nested(path->dentry->d_inode, I_MUTEX_PARENT);
-	dentry = __lookup_hash(&last, path->dentry, reval_flag | create_flags);
+	dentry = lookup_one_qstr_excl(&last, path->dentry,
+				      reval_flag | create_flags);
 	if (IS_ERR(dentry))
 		goto unlock;
 
@@ -4166,7 +4243,7 @@ int do_rmdir(int dfd, struct filename *name)
 		goto exit2;
 
 	inode_lock_nested(path.dentry->d_inode, I_MUTEX_PARENT);
-	dentry = __lookup_hash(&last, path.dentry, lookup_flags);
+	dentry = lookup_one_qstr_excl(&last, path.dentry, lookup_flags);
 	error = PTR_ERR(dentry);
 	if (IS_ERR(dentry))
 		goto exit3;
@@ -4299,7 +4376,7 @@ int do_unlinkat(int dfd, struct filename *name)
 		goto exit2;
 retry_deleg:
 	inode_lock_nested(path.dentry->d_inode, I_MUTEX_PARENT);
-	dentry = __lookup_hash(&last, path.dentry, lookup_flags);
+	dentry = lookup_one_qstr_excl(&last, path.dentry, lookup_flags);
 	error = PTR_ERR(dentry);
 	if (!IS_ERR(dentry)) {
 
@@ -4863,7 +4940,8 @@ int do_renameat2(int olddfd, struct filename *from, int newdfd,
 retry_deleg:
 	trap = lock_rename(new_path.dentry, old_path.dentry);
 
-	old_dentry = __lookup_hash(&old_last, old_path.dentry, lookup_flags);
+	old_dentry = lookup_one_qstr_excl(&old_last, old_path.dentry,
+					  lookup_flags);
 	error = PTR_ERR(old_dentry);
 	if (IS_ERR(old_dentry))
 		goto exit3;
@@ -4871,7 +4949,8 @@ int do_renameat2(int olddfd, struct filename *from, int newdfd,
 	error = -ENOENT;
 	if (d_is_negative(old_dentry))
 		goto exit4;
-	new_dentry = __lookup_hash(&new_last, new_path.dentry, lookup_flags | target_flags);
+	new_dentry = lookup_one_qstr_excl(&new_last, new_path.dentry,
+					  lookup_flags | target_flags);
 	error = PTR_ERR(new_dentry);
 	if (IS_ERR(new_dentry))
 		goto exit4;

include/linux/namei.h

@@ -57,12 +57,20 @@ 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_one_qstr_excl(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 *filename, unsigned int flags,
+			   struct path *parent, struct qstr *last, int *type,
+			   const struct path *root);
+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 +89,7 @@ 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);