[PATCH 3/8] eventfs: adding eventfs file add functions

Ajay Kaher
2023-01-22T17:07:49Z

Adding following function to eventfs to add files:

eventfs_add_top_file() will add the info of top file
to eventfs and dynamically create these files as and
when required.

eventfs_add_file() will add the info of nested files
to eventfs and dynamically create these dir as and
when required.

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>
---
fs/tracefs/event_inode.c | 108 +++++++++++++++++++++++++++++++++++++++++++++++
include/linux/tracefs.h | 8 ++++
2 files changed, 116 insertions(+)

diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c
index ef3b435..e479712 100644
--- a/fs/tracefs/event_inode.c
+++ b/fs/tracefs/event_inode.c
@@ -171,3 +171,111 @@ struct eventfs_file *eventfs_add_dir(const char *name, struct eventfs_file *ef_p
list_add_tail(&ef->list, &ef_parent->ei->e_top_files);
return ef;
}
+
+/**
+ * eventfs_add_top_file - add event top file to list to create later
+ * @name: a pointer to a string containing the name of the file to create.
+ * @mode: the permission that the file should have.
+ * @parent: a pointer to the parent dentry for this file. This should be a
+ * directory dentry if set. If this parameter is NULL, then the
+ * file will be created in the root of the tracefs filesystem.
+ * @data: a pointer to something that the caller will want to get to later
+ * on. The inode.i_private pointer will point to this value on
+ * the open() call.
+ * @fop: a pointer to a struct file_operations that should be used for
+ * this file.
+ *
+ * This function adds top files of event dir to list.
+ * And all these files are created on the fly when they are looked up,
+ * and the dentry and inodes will be removed when they are done.
+ */
+int eventfs_add_top_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 = kzalloc(sizeof(*ef), GFP_KERNEL);
+ if (!ef)
+ return -ENOMEM;
+
+ ef->name = kstrdup(name, GFP_KERNEL);
+ if (!ef->name) {
+ kfree(ef);
+ return -ENOMEM;
+ }
+
+ ef->mode = mode;
+ ef->data = data;
+ ef->fop = fop;
+ ef->dentry = NULL;
+ ef->ei = NULL;
+ ef->created = false;
+ ef->d_parent = parent;
+ list_add_tail(&ef->list, &ei->e_top_files);
+ return 0;
+}
+
+/**
+ * eventfs_add_file - add eventfs file to list to create later
+ * @name: a pointer to a string containing the name of the file to create.
+ * @mode: the permission that the file should have.
+ * @ef_parent: a pointer to the parent eventfs_file for this file.
+ * @data: a pointer to something that the caller will want to get to later
+ * on. The inode.i_private pointer will point to this value on
+ * the open() call.
+ * @fop: a pointer to a struct file_operations that should be used for
+ * this file.
+ *
+ * This function adds top files of event dir to list.
+ * And all these files are created on the fly when they are looked up,
+ * and the dentry and inodes will be removed when they are done.
+ */
+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 = kzalloc(sizeof(*ef), GFP_KERNEL);
+ if (!ef)
+ return -ENOMEM;
+
+ ef->name = kstrdup(name, GFP_KERNEL);
+ if (!ef->name) {
+ kfree(ef);
+ return -ENOMEM;
+ }
+
+ ef->mode = mode;
+ ef->data = data;
+ ef->fop = fop;
+ ef->dentry = NULL;
+ ef->ei = NULL;
+ ef->created = false;
+ list_add_tail(&ef->list, &ef_parent->ei->e_top_files);
+ return 0;
+}
diff --git a/include/linux/tracefs.h b/include/linux/tracefs.h
index 6983409..7d390d2 100644
--- a/include/linux/tracefs.h
+++ b/include/linux/tracefs.h
@@ -47,6 +47,14 @@ 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_top_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);
--
2.7.4