1 files changed, 48 insertions, 128 deletions

diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c
index 129d0f54ba..01e99e9845 100644
--- a/fs/tracefs/event_inode.c
+++ b/fs/tracefs/event_inode.c
@@ -37,7 +37,6 @@ static DEFINE_MUTEX(eventfs_mutex);
 
 struct eventfs_root_inode {
 	struct eventfs_inode		ei;
-	struct inode			*parent_inode;
 	struct dentry			*events_dir;
 };
 
@@ -113,7 +112,7 @@ static void release_ei(struct kref *ref)
 			entry->release(entry->name, ei->data);
 	}
 
-	call_rcu(&ei->rcu, free_ei_rcu);
+	call_srcu(&eventfs_srcu, &ei->rcu, free_ei_rcu);
 }
 
 static inline void put_ei(struct eventfs_inode *ei)
@@ -211,7 +210,9 @@ static int eventfs_set_attr(struct mnt_idmap *idmap, struct dentry *dentry,
 	 * determined by the parent directory.
 	 */
 	if (dentry->d_inode->i_mode & S_IFDIR) {
-		update_attr(&ei->attr, iattr);
+		/* Just use the inode permissions for the events directory */
+		if (!ei->is_events)
+			update_attr(&ei->attr, iattr);
 
 	} else {
 		name = dentry->d_name.name;
@@ -229,70 +230,9 @@ static int eventfs_set_attr(struct mnt_idmap *idmap, struct dentry *dentry,
 	return ret;
 }
 
-static void update_events_attr(struct eventfs_inode *ei, struct super_block *sb)
-{
-	struct eventfs_root_inode *rei;
-	struct inode *parent;
-
-	rei = get_root_inode(ei);
-
-	/* Use the parent inode permissions unless root set its permissions */
-	parent = rei->parent_inode;
-
-	if (rei->ei.attr.mode & EVENTFS_SAVE_UID)
-		ei->attr.uid = rei->ei.attr.uid;
-	else
-		ei->attr.uid = parent->i_uid;
-
-	if (rei->ei.attr.mode & EVENTFS_SAVE_GID)
-		ei->attr.gid = rei->ei.attr.gid;
-	else
-		ei->attr.gid = parent->i_gid;
-}
-
-static void set_top_events_ownership(struct inode *inode)
-{
-	struct tracefs_inode *ti = get_tracefs(inode);
-	struct eventfs_inode *ei = ti->private;
-
-	/* The top events directory doesn't get automatically updated */
-	if (!ei || !ei->is_events)
-		return;
-
-	update_events_attr(ei, inode->i_sb);
-
-	if (!(ei->attr.mode & EVENTFS_SAVE_UID))
-		inode->i_uid = ei->attr.uid;
-
-	if (!(ei->attr.mode & EVENTFS_SAVE_GID))
-		inode->i_gid = ei->attr.gid;
-}
-
-static int eventfs_get_attr(struct mnt_idmap *idmap,
-			    const struct path *path, struct kstat *stat,
-			    u32 request_mask, unsigned int flags)
-{
-	struct dentry *dentry = path->dentry;
-	struct inode *inode = d_backing_inode(dentry);
-
-	set_top_events_ownership(inode);
-
-	generic_fillattr(idmap, request_mask, inode, stat);
-	return 0;
-}
-
-static int eventfs_permission(struct mnt_idmap *idmap,
-			      struct inode *inode, int mask)
-{
-	set_top_events_ownership(inode);
-	return generic_permission(idmap, inode, mask);
-}
-
 static const struct inode_operations eventfs_dir_inode_operations = {
 	.lookup		= eventfs_root_lookup,
 	.setattr	= eventfs_set_attr,
-	.getattr	= eventfs_get_attr,
-	.permission	= eventfs_permission,
 };
 
 static const struct inode_operations eventfs_file_inode_operations = {
@@ -361,55 +301,53 @@ void eventfs_remount(struct tracefs_inode *ti, bool update_uid, bool update_gid)
 			  update_gid, ti->vfs_inode.i_gid, 0);
 }
 
-/* Return the evenfs_inode of the "events" directory */
-static struct eventfs_inode *eventfs_find_events(struct dentry *dentry)
+static void update_inode_attr(struct inode *inode, umode_t mode,
+			      struct eventfs_attr *attr, struct eventfs_root_inode *rei)
 {
-	struct eventfs_inode *ei;
-
-	do {
-		// The parent is stable because we do not do renames
-		dentry = dentry->d_parent;
-		// ... and directories always have d_fsdata
-		ei = dentry->d_fsdata;
-
-		/*
-		 * If the ei is being freed, the ownership of the children
-		 * doesn't matter.
-		 */
-		if (ei->is_freed)
-			return NULL;
-
-		// Walk upwards until you find the events inode
-	} while (!ei->is_events);
+	if (attr && attr->mode & EVENTFS_SAVE_MODE)
+		inode->i_mode = attr->mode & EVENTFS_MODE_MASK;
+	else
+		inode->i_mode = mode;
 
-	update_events_attr(ei, dentry->d_sb);
+	if (attr && attr->mode & EVENTFS_SAVE_UID)
+		inode->i_uid = attr->uid;
+	else
+		inode->i_uid = rei->ei.attr.uid;
 
-	return ei;
+	if (attr && attr->mode & EVENTFS_SAVE_GID)
+		inode->i_gid = attr->gid;
+	else
+		inode->i_gid = rei->ei.attr.gid;
 }
 
-static void update_inode_attr(struct dentry *dentry, struct inode *inode,
-			      struct eventfs_attr *attr, umode_t mode)
+static struct inode *eventfs_get_inode(struct dentry *dentry, struct eventfs_attr *attr,
+				       umode_t mode,  struct eventfs_inode *ei)
 {
-	struct eventfs_inode *events_ei = eventfs_find_events(dentry);
+	struct eventfs_root_inode *rei;
+	struct eventfs_inode *pei;
+	struct tracefs_inode *ti;
+	struct inode *inode;
 
-	if (!events_ei)
-		return;
+	inode = tracefs_get_inode(dentry->d_sb);
+	if (!inode)
+		return NULL;
 
-	inode->i_mode = mode;
-	inode->i_uid = events_ei->attr.uid;
-	inode->i_gid = events_ei->attr.gid;
+	ti = get_tracefs(inode);
+	ti->private = ei;
+	ti->flags |= TRACEFS_EVENT_INODE;
 
-	if (!attr)
-		return;
+	/* Find the top dentry that holds the "events" directory */
+	do {
+		dentry = dentry->d_parent;
+		/* Directories always have d_fsdata */
+		pei = dentry->d_fsdata;
+	} while (!pei->is_events);
 
-	if (attr->mode & EVENTFS_SAVE_MODE)
-		inode->i_mode = attr->mode & EVENTFS_MODE_MASK;
+	rei = get_root_inode(pei);
 
-	if (attr->mode & EVENTFS_SAVE_UID)
-		inode->i_uid = attr->uid;
+	update_inode_attr(inode, mode, attr, rei);
 
-	if (attr->mode & EVENTFS_SAVE_GID)
-		inode->i_gid = attr->gid;
+	return inode;
 }
 
 /**
@@ -432,7 +370,6 @@ static struct dentry *lookup_file(struct eventfs_inode *parent_ei,
 				  void *data,
 				  const struct file_operations *fop)
 {
-	struct tracefs_inode *ti;
 	struct inode *inode;
 
 	if (!(mode & S_IFMT))
@@ -441,13 +378,11 @@ static struct dentry *lookup_file(struct eventfs_inode *parent_ei,
 	if (WARN_ON_ONCE(!S_ISREG(mode)))
 		return ERR_PTR(-EIO);
 
-	inode = tracefs_get_inode(dentry->d_sb);
+	/* Only directories have ti->private set to an ei, not files */
+	inode = eventfs_get_inode(dentry, attr, mode, NULL);
 	if (unlikely(!inode))
 		return ERR_PTR(-ENOMEM);
 
-	/* If the user updated the directory's attributes, use them */
-	update_inode_attr(dentry, inode, attr, mode);
-
 	inode->i_op = &eventfs_file_inode_operations;
 	inode->i_fop = fop;
 	inode->i_private = data;
@@ -455,9 +390,6 @@ static struct dentry *lookup_file(struct eventfs_inode *parent_ei,
 	/* All files will have the same inode number */
 	inode->i_ino = EVENTFS_FILE_INODE_INO;
 
-	ti = get_tracefs(inode);
-	ti->flags |= TRACEFS_EVENT_INODE;
-
 	// Files have their parent's ei as their fsdata
 	dentry->d_fsdata = get_ei(parent_ei);
 
@@ -477,28 +409,19 @@ static struct dentry *lookup_file(struct eventfs_inode *parent_ei,
 static struct dentry *lookup_dir_entry(struct dentry *dentry,
 	struct eventfs_inode *pei, struct eventfs_inode *ei)
 {
-	struct tracefs_inode *ti;
 	struct inode *inode;
+	umode_t mode = S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO;
 
-	inode = tracefs_get_inode(dentry->d_sb);
+	inode = eventfs_get_inode(dentry, &ei->attr, mode, ei);
 	if (unlikely(!inode))
 		return ERR_PTR(-ENOMEM);
 
-	/* If the user updated the directory's attributes, use them */
-	update_inode_attr(dentry, inode, &ei->attr,
-			  S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO);
-
 	inode->i_op = &eventfs_dir_inode_operations;
 	inode->i_fop = &eventfs_file_operations;
 
 	/* All directories will have the same inode number */
 	inode->i_ino = eventfs_dir_ino(ei);
 
-	ti = get_tracefs(inode);
-	ti->flags |= TRACEFS_EVENT_INODE;
-	/* Only directories have ti->private set to an ei, not files */
-	ti->private = ei;
-
 	dentry->d_fsdata = get_ei(ei);
 
 	d_add(dentry, inode);
@@ -813,7 +736,7 @@ struct eventfs_inode *eventfs_create_dir(const char *name, struct eventfs_inode
 	/* Was the parent freed? */
 	if (list_empty(&ei->list)) {
 		cleanup_ei(ei);
-		ei = NULL;
+		ei = ERR_PTR(-EBUSY);
 	}
 	return ei;
 }
@@ -859,7 +782,6 @@ struct eventfs_inode *eventfs_create_events_dir(const char *name, struct dentry
 	// Note: we have a ref to the dentry from tracefs_start_creating()
 	rei = get_root_inode(ei);
 	rei->events_dir = dentry;
-	rei->parent_inode = d_inode(dentry->d_sb->s_root);
 
 	ei->entries = entries;
 	ei->nr_entries = size;
@@ -869,14 +791,12 @@ struct eventfs_inode *eventfs_create_events_dir(const char *name, struct dentry
 	uid = d_inode(dentry->d_parent)->i_uid;
 	gid = d_inode(dentry->d_parent)->i_gid;
 
-	ei->attr.uid = uid;
-	ei->attr.gid = gid;
-
 	/*
-	 * When the "events" directory is created, it takes on the
-	 * permissions of its parent. But can be reset on remount.
+	 * The ei->attr will be used as the default values for the
+	 * files beneath this directory.
 	 */
-	ei->attr.mode |= EVENTFS_SAVE_UID | EVENTFS_SAVE_GID;
+	ei->attr.uid = uid;
+	ei->attr.gid = gid;
 
 	INIT_LIST_HEAD(&ei->children);
 	INIT_LIST_HEAD(&ei->list);