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Message-Id: <1685610013-33478-8-git-send-email-akaher@vmware.com>
Date: Thu, 1 Jun 2023 14:30:10 +0530
From: Ajay Kaher <akaher@...are.com>
To: rostedt@...dmis.org, mhiramat@...nel.org, shuah@...nel.org
Cc: linux-kernel@...r.kernel.org, linux-trace-kernel@...r.kernel.org,
linux-kselftest@...r.kernel.org, chinglinyu@...gle.com,
namit@...are.com, srivatsa@...il.mit.edu, amakhalov@...are.com,
vsirnapalli@...are.com, tkundu@...are.com, er.ajay.kaher@...il.com,
Ajay Kaher <akaher@...are.com>
Subject: [PATCH v3 07/10] eventfs: adding eventfs lookup, read, open functions
Adding following inode_operations, file_operations and helper functions to
eventfs:
dcache_dir_open_wrapper()
eventfs_root_lookup()
eventfs_release()
eventfs_set_ef_status_free()
eventfs_post_create_dir()
inode_operations, file_operations will be called from vfs.
Signed-off-by: Ajay Kaher <akaher@...are.com>
Co-developed-by: Steven Rostedt (VMware) <rostedt@...dmis.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@...dmis.org>
Tested-by: Ching-lin Yu <chinglinyu@...gle.com>
---
fs/tracefs/event_inode.c | 188 +++++++++++++++++++++++++++++++++++++++
include/linux/tracefs.h | 2 +
2 files changed, 190 insertions(+)
diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c
index 0ac1913cf..d98ded15d 100644
--- a/fs/tracefs/event_inode.c
+++ b/fs/tracefs/event_inode.c
@@ -208,10 +208,198 @@ static struct dentry *eventfs_create_dir(const char *name, umode_t mode,
return eventfs_end_creating(dentry);
}
+/**
+ * eventfs_set_ef_status_free - set the ef->status to free
+ * @dentry: dentry who's status to be freed
+ *
+ * eventfs_set_ef_status_free will be called if no more
+ * reference remains
+ */
+void eventfs_set_ef_status_free(struct dentry *dentry)
+{
+ struct tracefs_inode *ti_parent;
+ struct eventfs_file *ef;
+
+ ti_parent = get_tracefs(dentry->d_parent->d_inode);
+ if (!ti_parent || !(ti_parent->flags & TRACEFS_EVENT_INODE))
+ return;
+
+ ef = dentry->d_fsdata;
+ if (!ef)
+ return;
+ ef->created = false;
+ ef->dentry = NULL;
+}
+
+/**
+ * eventfs_post_create_dir - post create dir routine
+ * @ef: eventfs_file of recently created dir
+ *
+ * Files with-in eventfs dir should know dentry of parent dir
+ */
+static void eventfs_post_create_dir(struct eventfs_file *ef)
+{
+ struct eventfs_file *ef_child;
+ struct tracefs_inode *ti;
+
+ eventfs_down_read((struct rw_semaphore *) ef->data);
+ /* fill parent-child relation */
+ list_for_each_entry(ef_child, &ef->ei->e_top_files, list) {
+ ef_child->d_parent = ef->dentry;
+ }
+ eventfs_up_read((struct rw_semaphore *) ef->data);
+
+ ti = get_tracefs(ef->dentry->d_inode);
+ ti->private = ef->ei;
+}
+
+/**
+ * eventfs_root_lookup - lookup routine to create file/dir
+ * @dir: directory in which lookup to be done
+ * @dentry: file/dir dentry
+ * @flags:
+ *
+ * Used to create dynamic file/dir with-in @dir, search with-in ei
+ * list, if @dentry found go ahead and create the file/dir
+ */
+
+static struct dentry *eventfs_root_lookup(struct inode *dir,
+ struct dentry *dentry,
+ unsigned int flags)
+{
+ struct tracefs_inode *ti;
+ struct eventfs_inode *ei;
+ struct eventfs_file *ef;
+ struct dentry *ret = NULL;
+ struct rw_semaphore *eventfs_rwsem;
+
+ ti = get_tracefs(dir);
+ if (!(ti->flags & TRACEFS_EVENT_INODE))
+ return NULL;
+
+ ei = ti->private;
+ eventfs_rwsem = (struct rw_semaphore *) dir->i_private;
+ eventfs_down_read(eventfs_rwsem);
+ list_for_each_entry(ef, &ei->e_top_files, list) {
+ if (strcmp(ef->name, dentry->d_name.name))
+ continue;
+ ret = simple_lookup(dir, dentry, flags);
+ if (ef->created)
+ continue;
+ ef->created = true;
+ if (ef->ei)
+ ef->dentry = eventfs_create_dir(ef->name, ef->mode, ef->d_parent,
+ ef->data, ef->fop, ef->iop);
+ else
+ ef->dentry = eventfs_create_file(ef->name, ef->mode, ef->d_parent,
+ ef->data, ef->fop);
+
+ if (IS_ERR_OR_NULL(ef->dentry)) {
+ ef->created = false;
+ } else {
+ if (ef->ei)
+ eventfs_post_create_dir(ef);
+ ef->dentry->d_fsdata = ef;
+ dput(ef->dentry);
+ }
+ break;
+ }
+ eventfs_up_read(eventfs_rwsem);
+ return ret;
+}
+
+/**
+ * eventfs_release - called to release eventfs file/dir
+ * @inode: inode to be released
+ * @file: file to be released (not used)
+ */
+static int eventfs_release(struct inode *inode, struct file *file)
+{
+ struct tracefs_inode *ti;
+ struct eventfs_inode *ei;
+ struct eventfs_file *ef;
+ struct dentry *dentry = file_dentry(file);
+ struct rw_semaphore *eventfs_rwsem;
+
+ ti = get_tracefs(inode);
+ if (!(ti->flags & TRACEFS_EVENT_INODE))
+ return -EINVAL;
+
+ ei = ti->private;
+ eventfs_rwsem = eventfs_dentry_to_rwsem(dentry);
+ eventfs_down_read(eventfs_rwsem);
+ list_for_each_entry(ef, &ei->e_top_files, list) {
+ if (ef->created)
+ dput(ef->dentry);
+ }
+ eventfs_up_read(eventfs_rwsem);
+ return dcache_dir_close(inode, file);
+}
+
+/**
+ * dcache_dir_open_wrapper - eventfs open wrapper
+ * @inode: not used
+ * @file: dir to be opened (to create it's child)
+ *
+ * Used to dynamic create file/dir with-in @file, all the
+ * file/dir will be created. If already created then reference
+ * will be increased
+ */
+static int dcache_dir_open_wrapper(struct inode *inode, struct file *file)
+{
+ struct tracefs_inode *ti;
+ struct eventfs_inode *ei;
+ struct eventfs_file *ef;
+ struct inode *f_inode = file_inode(file);
+ struct dentry *dentry = file_dentry(file);
+ struct rw_semaphore *eventfs_rwsem;
+
+ ti = get_tracefs(f_inode);
+ if (!(ti->flags & TRACEFS_EVENT_INODE))
+ return -EINVAL;
+
+ ei = ti->private;
+ eventfs_rwsem = eventfs_dentry_to_rwsem(dentry);
+ eventfs_down_read(eventfs_rwsem);
+ list_for_each_entry(ef, &ei->e_top_files, list) {
+ if (ef->created) {
+ dget(ef->dentry);
+ continue;
+ }
+
+ ef->created = true;
+
+ inode_lock(dentry->d_inode);
+ if (ef->ei)
+ ef->dentry = eventfs_create_dir(ef->name, ef->mode, dentry,
+ ef->data, ef->fop, ef->iop);
+ else
+ ef->dentry = eventfs_create_file(ef->name, ef->mode, dentry,
+ ef->data, ef->fop);
+ inode_unlock(dentry->d_inode);
+
+ if (IS_ERR_OR_NULL(ef->dentry)) {
+ ef->created = false;
+ } else {
+ if (ef->ei)
+ eventfs_post_create_dir(ef);
+ ef->dentry->d_fsdata = ef;
+ }
+ }
+ eventfs_up_read(eventfs_rwsem);
+ return dcache_dir_open(inode, file);
+}
+
static const struct file_operations eventfs_file_operations = {
+ .open = dcache_dir_open_wrapper,
+ .read = generic_read_dir,
+ .iterate_shared = dcache_readdir,
+ .llseek = generic_file_llseek,
+ .release = eventfs_release,
};
static const struct inode_operations eventfs_root_dir_inode_operations = {
+ .lookup = eventfs_root_lookup,
};
/**
diff --git a/include/linux/tracefs.h b/include/linux/tracefs.h
index 57bfd1322..268450d60 100644
--- a/include/linux/tracefs.h
+++ b/include/linux/tracefs.h
@@ -68,6 +68,8 @@ void eventfs_remove(struct eventfs_file *ef);
void eventfs_remove_events_dir(struct dentry *dentry);
+void eventfs_set_ef_status_free(struct dentry *dentry);
+
struct dentry *tracefs_create_file(const char *name, umode_t mode,
struct dentry *parent, void *data,
const struct file_operations *fops);
--
2.40.0
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