eventfs: Implement eventfs file add functions

Add the following functions to add files to evenfs:

eventfs_add_events_file() to add the data needed to create a specific file
located at the top level events directory. The dentry/inode will be
created when the events directory is scanned.

eventfs_add_file() to add the data needed for files within the directories
below the top level events directory. The dentry/inode of the file will be
created when the directory that the file is in is scanned.

Link: https://lkml.kernel.org/r/1690568452-46553-6-git-send-email-akaher@vmware.com
Signed-off-by: Ajay Kaher <akaher@vmware.com>
Co-developed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Tested-by: Ching-lin Yu <chinglinyu@google.com>
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-lkp/202305051619.9a469a9a-yujie.liu@intel.com
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c
index 8f334b122e464c4b45fa6f4caa8e889d9306a933..9e4843be9dc94d9dbbe3c41c5640905b1d9ce5c3 100644 (file)
--- a/fs/tracefs/event_inode.c
+++ b/fs/tracefs/event_inode.c
@@ -209,3 +209,89 @@ struct eventfs_file *eventfs_add_dir(const char *name,
        mutex_unlock(&eventfs_mutex);
        return ef;
 }
+
+/**
+ * eventfs_add_events_file - add the data needed to create a file for later reference
+ * @name: the name of the file to create.
+ * @mode: the permission that the file should have.
+ * @parent: parent dentry for this file.
+ * @data: something that the caller will want to get to later on.
+ * @fop: struct file_operations that should be used for this file.
+ *
+ * This function is used to add the information needed to create a
+ * dentry/inode within the top level events directory. The file created
+ * will have the @mode permissions. The @data will be used to fill the
+ * inode.i_private when the open() call is done. The dentry and inodes are
+ * all created when they are referenced, and removed when they are no
+ * longer referenced.
+ */
+int eventfs_add_events_file(const char *name, umode_t mode,
+                        struct dentry *parent, void *data,
+                        const struct file_operations *fop)
+{
+       struct tracefs_inode *ti;
+       struct eventfs_inode *ei;
+       struct eventfs_file *ef;
+
+       if (!parent)
+               return -EINVAL;
+
+       if (!(mode & S_IFMT))
+               mode |= S_IFREG;
+
+       if (!parent->d_inode)
+               return -EINVAL;
+
+       ti = get_tracefs(parent->d_inode);
+       if (!(ti->flags & TRACEFS_EVENT_INODE))
+               return -EINVAL;
+
+       ei = ti->private;
+       ef = eventfs_prepare_ef(name, mode, fop, NULL, data);
+
+       if (IS_ERR(ef))
+               return -ENOMEM;
+
+       mutex_lock(&eventfs_mutex);
+       list_add_tail(&ef->list, &ei->e_top_files);
+       mutex_unlock(&eventfs_mutex);
+       return 0;
+}
+
+/**
+ * eventfs_add_file - add eventfs file to list to create later
+ * @name: the name of the file to create.
+ * @mode: the permission that the file should have.
+ * @ef_parent: parent eventfs_file for this file.
+ * @data: something that the caller will want to get to later on.
+ * @fop: struct file_operations that should be used for this file.
+ *
+ * This function is used to add the information needed to create a
+ * file within a subdirectory of the events directory. The file created
+ * will have the @mode permissions. The @data will be used to fill the
+ * inode.i_private when the open() call is done. The dentry and inodes are
+ * all created when they are referenced, and removed when they are no
+ * longer referenced.
+ */
+int eventfs_add_file(const char *name, umode_t mode,
+                    struct eventfs_file *ef_parent,
+                    void *data,
+                    const struct file_operations *fop)
+{
+       struct eventfs_file *ef;
+
+       if (!ef_parent)
+               return -EINVAL;
+
+       if (!(mode & S_IFMT))
+               mode |= S_IFREG;
+
+       ef = eventfs_prepare_ef(name, mode, fop, NULL, data);
+       if (IS_ERR(ef))
+               return -ENOMEM;
+
+       mutex_lock(&eventfs_mutex);
+       list_add_tail(&ef->list, &ef_parent->ei->e_top_files);
+       mutex_unlock(&eventfs_mutex);
+       return 0;
+}

diff --git a/include/linux/tracefs.h b/include/linux/tracefs.h
index 432e5e6f790182fa90fefe93f95676ceb20762cc..54c9cbd0389b8f5d8ccb28071bf76301d4317077 100644 (file)
--- a/include/linux/tracefs.h
+++ b/include/linux/tracefs.h
@@ -32,6 +32,14 @@ struct eventfs_file *eventfs_add_subsystem_dir(const char *name,
 struct eventfs_file *eventfs_add_dir(const char *name,
                                     struct eventfs_file *ef_parent);
 
+int eventfs_add_file(const char *name, umode_t mode,
+                    struct eventfs_file *ef_parent, void *data,
+                    const struct file_operations *fops);
+
+int eventfs_add_events_file(const char *name, umode_t mode,
+                        struct dentry *parent, void *data,
+                        const struct file_operations *fops);
+
 struct dentry *tracefs_create_file(const char *name, umode_t mode,
                                   struct dentry *parent, void *data,
                                   const struct file_operations *fops);