@@ -230,7 +230,6 @@ static struct eventfs_inode *eventfs_find_events(struct dentry *dentry)
{
struct eventfs_inode *ei;
- mutex_lock(&eventfs_mutex);
do {
// The parent is stable because we do not do renames
dentry = dentry->d_parent;
@@ -247,7 +246,6 @@ static struct eventfs_inode *eventfs_find_events(struct dentry *dentry)
}
// Walk upwards until you find the events inode
} while (!ei->is_events);
- mutex_unlock(&eventfs_mutex);
update_top_events_attr(ei, dentry->d_sb);
@@ -280,11 +278,10 @@ static void update_inode_attr(struct dentry *dentry, struct inode *inode,
}
/**
- * create_file - create a file in the tracefs filesystem
- * @name: the name of the file to create.
+ * lookup_file - look up a file in the tracefs filesystem
+ * @dentry: the dentry to look up
* @mode: the permission that the file should have.
* @attr: saved attributes changed by user
- * @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.
*
@@ -292,13 +289,13 @@ static void update_inode_attr(struct dentry *dentry, struct inode *inode,
* directory. The inode.i_private pointer will point to @data in the open()
* call.
*/
-static struct dentry *create_file(const char *name, umode_t mode,
+static struct dentry *lookup_file(struct dentry *dentry,
+ umode_t mode,
struct eventfs_attr *attr,
- struct dentry *parent, void *data,
+ void *data,
const struct file_operations *fop)
{
struct tracefs_inode *ti;
- struct dentry *dentry;
struct inode *inode;
if (!(mode & S_IFMT))
@@ -307,15 +304,9 @@ static struct dentry *create_file(const char *name, umode_t mode,
if (WARN_ON_ONCE(!S_ISREG(mode)))
return NULL;
- WARN_ON_ONCE(!parent);
- dentry = eventfs_start_creating(name, parent);
-
- if (IS_ERR(dentry))
- return dentry;
-
inode = tracefs_get_inode(dentry->d_sb);
if (unlikely(!inode))
- return eventfs_failed_creating(dentry);
+ return ERR_PTR(-ENOMEM);
/* If the user updated the directory's attributes, use them */
update_inode_attr(dentry, inode, attr, mode);
@@ -329,32 +320,29 @@ static struct dentry *create_file(const char *name, umode_t mode,
ti = get_tracefs(inode);
ti->flags |= TRACEFS_EVENT_INODE;
- d_instantiate(dentry, inode);
+
+ d_add(dentry, inode);
fsnotify_create(dentry->d_parent->d_inode, dentry);
- return eventfs_end_creating(dentry);
+ return dentry;
};
/**
- * create_dir - create a dir in the tracefs filesystem
+ * lookup_dir_entry - look up a dir in the tracefs filesystem
+ * @dentry: the directory to look up
* @ei: the eventfs_inode that represents the directory to create
- * @parent: parent dentry for this file.
*
- * This function will create a dentry for a directory represented by
+ * This function will look up a dentry for a directory represented by
* a eventfs_inode.
*/
-static struct dentry *create_dir(struct eventfs_inode *ei, struct dentry *parent)
+static struct dentry *lookup_dir_entry(struct dentry *dentry,
+ struct eventfs_inode *pei, struct eventfs_inode *ei)
{
struct tracefs_inode *ti;
- struct dentry *dentry;
struct inode *inode;
- dentry = eventfs_start_creating(ei->name, parent);
- if (IS_ERR(dentry))
- return dentry;
-
inode = tracefs_get_inode(dentry->d_sb);
if (unlikely(!inode))
- return eventfs_failed_creating(dentry);
+ return ERR_PTR(-ENOMEM);
/* If the user updated the directory's attributes, use them */
update_inode_attr(dentry, inode, &ei->attr,
@@ -371,11 +359,14 @@ static struct dentry *create_dir(struct eventfs_inode *ei, struct dentry *parent
/* Only directories have ti->private set to an ei, not files */
ti->private = ei;
+ dentry->d_fsdata = ei;
+ ei->dentry = dentry; // Remove me!
+
inc_nlink(inode);
- d_instantiate(dentry, inode);
+ d_add(dentry, inode);
inc_nlink(dentry->d_parent->d_inode);
fsnotify_mkdir(dentry->d_parent->d_inode, dentry);
- return eventfs_end_creating(dentry);
+ return dentry;
}
static void free_ei(struct eventfs_inode *ei)
@@ -425,7 +416,7 @@ void eventfs_set_ei_status_free(struct tracefs_inode *ti, struct dentry *dentry)
}
/**
- * create_file_dentry - create a dentry for a file of an eventfs_inode
+ * lookup_file_dentry - create a dentry for a file of an eventfs_inode
* @ei: the eventfs_inode that the file will be created under
* @idx: the index into the d_children[] of the @ei
* @parent: The parent dentry of the created file.
@@ -438,157 +429,21 @@ void eventfs_set_ei_status_free(struct tracefs_inode *ti, struct dentry *dentry)
* address located at @e_dentry.
*/
static struct dentry *
-create_file_dentry(struct eventfs_inode *ei, int idx,
- struct dentry *parent, const char *name, umode_t mode, void *data,
+lookup_file_dentry(struct dentry *dentry,
+ struct eventfs_inode *ei, int idx,
+ umode_t mode, void *data,
const struct file_operations *fops)
{
struct eventfs_attr *attr = NULL;
struct dentry **e_dentry = &ei->d_children[idx];
- struct dentry *dentry;
-
- WARN_ON_ONCE(!inode_is_locked(parent->d_inode));
- mutex_lock(&eventfs_mutex);
- if (ei->is_freed) {
- mutex_unlock(&eventfs_mutex);
- return NULL;
- }
- /* If the e_dentry already has a dentry, use it */
- if (*e_dentry) {
- dget(*e_dentry);
- mutex_unlock(&eventfs_mutex);
- return *e_dentry;
- }
-
- /* ei->entry_attrs are protected by SRCU */
if (ei->entry_attrs)
attr = &ei->entry_attrs[idx];
- mutex_unlock(&eventfs_mutex);
-
- dentry = create_file(name, mode, attr, parent, data, fops);
-
- mutex_lock(&eventfs_mutex);
-
- if (IS_ERR_OR_NULL(dentry)) {
- /*
- * When the mutex was released, something else could have
- * created the dentry for this e_dentry. In which case
- * use that one.
- *
- * If ei->is_freed is set, the e_dentry is currently on its
- * way to being freed, don't return it. If e_dentry is NULL
- * it means it was already freed.
- */
- if (ei->is_freed) {
- dentry = NULL;
- } else {
- dentry = *e_dentry;
- dget(dentry);
- }
- mutex_unlock(&eventfs_mutex);
- return dentry;
- }
-
- if (!*e_dentry && !ei->is_freed) {
- *e_dentry = dentry;
- dentry->d_fsdata = ei;
- } else {
- /*
- * Should never happen unless we get here due to being freed.
- * Otherwise it means two dentries exist with the same name.
- */
- WARN_ON_ONCE(!ei->is_freed);
- dentry = NULL;
- }
- mutex_unlock(&eventfs_mutex);
-
- return dentry;
-}
-
-/**
- * eventfs_post_create_dir - post create dir routine
- * @ei: eventfs_inode of recently created dir
- *
- * Map the meta-data of files within an eventfs dir to their parent dentry
- */
-static void eventfs_post_create_dir(struct eventfs_inode *ei)
-{
- struct eventfs_inode *ei_child;
-
- lockdep_assert_held(&eventfs_mutex);
-
- /* srcu lock already held */
- /* fill parent-child relation */
- list_for_each_entry_srcu(ei_child, &ei->children, list,
- srcu_read_lock_held(&eventfs_srcu)) {
- ei_child->d_parent = ei->dentry;
- }
-}
-
-/**
- * create_dir_dentry - Create a directory dentry for the eventfs_inode
- * @pei: The eventfs_inode parent of ei.
- * @ei: The eventfs_inode to create the directory for
- * @parent: The dentry of the parent of this directory
- *
- * This creates and attaches a directory dentry to the eventfs_inode @ei.
- */
-static struct dentry *
-create_dir_dentry(struct eventfs_inode *pei, struct eventfs_inode *ei,
- struct dentry *parent)
-{
- struct dentry *dentry = NULL;
-
- WARN_ON_ONCE(!inode_is_locked(parent->d_inode));
-
- mutex_lock(&eventfs_mutex);
- if (pei->is_freed || ei->is_freed) {
- mutex_unlock(&eventfs_mutex);
- return NULL;
- }
- if (ei->dentry) {
- /* If the eventfs_inode already has a dentry, use it */
- dentry = ei->dentry;
- dget(dentry);
- mutex_unlock(&eventfs_mutex);
- return dentry;
- }
- mutex_unlock(&eventfs_mutex);
+ dentry->d_fsdata = ei; // NOTE: ei of _parent_
+ lookup_file(dentry, mode, attr, data, fops);
- dentry = create_dir(ei, parent);
-
- mutex_lock(&eventfs_mutex);
-
- if (IS_ERR_OR_NULL(dentry) && !ei->is_freed) {
- /*
- * When the mutex was released, something else could have
- * created the dentry for this e_dentry. In which case
- * use that one.
- *
- * If ei->is_freed is set, the e_dentry is currently on its
- * way to being freed.
- */
- dentry = ei->dentry;
- if (dentry)
- dget(dentry);
- mutex_unlock(&eventfs_mutex);
- return dentry;
- }
-
- if (!ei->dentry && !ei->is_freed) {
- ei->dentry = dentry;
- eventfs_post_create_dir(ei);
- dentry->d_fsdata = ei;
- } else {
- /*
- * Should never happen unless we get here due to being freed.
- * Otherwise it means two dentries exist with the same name.
- */
- WARN_ON_ONCE(!ei->is_freed);
- dentry = NULL;
- }
- mutex_unlock(&eventfs_mutex);
+ *e_dentry = dentry; // Remove me
return dentry;
}
@@ -607,79 +462,55 @@ static struct dentry *eventfs_root_lookup(struct inode *dir,
struct dentry *dentry,
unsigned int flags)
{
- const struct file_operations *fops;
- const struct eventfs_entry *entry;
struct eventfs_inode *ei_child;
struct tracefs_inode *ti;
struct eventfs_inode *ei;
- struct dentry *ei_dentry = NULL;
- struct dentry *ret = NULL;
- struct dentry *d;
const char *name = dentry->d_name.name;
- umode_t mode;
- void *data;
- int idx;
- int i;
- int r;
+ struct dentry *result = NULL;
ti = get_tracefs(dir);
if (!(ti->flags & TRACEFS_EVENT_INODE))
- return NULL;
-
- /* Grab srcu to prevent the ei from going away */
- idx = srcu_read_lock(&eventfs_srcu);
+ return ERR_PTR(-EIO);
- /*
- * Grab the eventfs_mutex to consistent value from ti->private.
- * This s
- */
mutex_lock(&eventfs_mutex);
- ei = READ_ONCE(ti->private);
- if (ei && !ei->is_freed)
- ei_dentry = READ_ONCE(ei->dentry);
- mutex_unlock(&eventfs_mutex);
-
- if (!ei || !ei_dentry)
- goto out;
- data = ei->data;
+ ei = ti->private;
+ if (!ei || ei->is_freed)
+ goto enoent;
- list_for_each_entry_srcu(ei_child, &ei->children, list,
- srcu_read_lock_held(&eventfs_srcu)) {
+ list_for_each_entry(ei_child, &ei->children, list) {
if (strcmp(ei_child->name, name) != 0)
continue;
- ret = simple_lookup(dir, dentry, flags);
- if (IS_ERR(ret))
- goto out;
- d = create_dir_dentry(ei, ei_child, ei_dentry);
- dput(d);
+ if (ei_child->is_freed)
+ goto enoent;
+ lookup_dir_entry(dentry, ei, ei_child);
goto out;
}
- for (i = 0; i < ei->nr_entries; i++) {
- entry = &ei->entries[i];
- if (strcmp(name, entry->name) == 0) {
- void *cdata = data;
- mutex_lock(&eventfs_mutex);
- /* If ei->is_freed, then the event itself may be too */
- if (!ei->is_freed)
- r = entry->callback(name, &mode, &cdata, &fops);
- else
- r = -1;
- mutex_unlock(&eventfs_mutex);
- if (r <= 0)
- continue;
- ret = simple_lookup(dir, dentry, flags);
- if (IS_ERR(ret))
- goto out;
- d = create_file_dentry(ei, i, ei_dentry, name, mode, cdata, fops);
- dput(d);
- break;
- }
+ for (int i = 0; i < ei->nr_entries; i++) {
+ void *data;
+ umode_t mode;
+ const struct file_operations *fops;
+ const struct eventfs_entry *entry = &ei->entries[i];
+
+ if (strcmp(name, entry->name) != 0)
+ continue;
+
+ data = ei->data;
+ if (entry->callback(name, &mode, &data, &fops) <= 0)
+ goto enoent;
+
+ lookup_file_dentry(dentry, ei, i, mode, data, fops);
+ goto out;
}
+
+ enoent:
+ /* Don't cache negative lookups, just return an error */
+ result = ERR_PTR(-ENOENT);
+
out:
- srcu_read_unlock(&eventfs_srcu, idx);
- return ret;
+ mutex_unlock(&eventfs_mutex);
+ return result;
}
/*
@@ -495,75 +495,6 @@ struct dentry *tracefs_end_creating(struct dentry *dentry)
return dentry;
}
-/**
- * eventfs_start_creating - start the process of creating a dentry
- * @name: Name of the file created for the dentry
- * @parent: The parent dentry where this dentry will be created
- *
- * This is a simple helper function for the dynamically created eventfs
- * files. When the directory of the eventfs files are accessed, their
- * dentries are created on the fly. This function is used to start that
- * process.
- */
-struct dentry *eventfs_start_creating(const char *name, struct dentry *parent)
-{
- struct dentry *dentry;
- int error;
-
- /* Must always have a parent. */
- if (WARN_ON_ONCE(!parent))
- return ERR_PTR(-EINVAL);
-
- error = simple_pin_fs(&trace_fs_type, &tracefs_mount,
- &tracefs_mount_count);
- if (error)
- return ERR_PTR(error);
-
- if (unlikely(IS_DEADDIR(parent->d_inode)))
- dentry = ERR_PTR(-ENOENT);
- else
- dentry = lookup_one_len(name, parent, strlen(name));
-
- if (!IS_ERR(dentry) && dentry->d_inode) {
- dput(dentry);
- dentry = ERR_PTR(-EEXIST);
- }
-
- if (IS_ERR(dentry))
- simple_release_fs(&tracefs_mount, &tracefs_mount_count);
-
- return dentry;
-}
-
-/**
- * eventfs_failed_creating - clean up a failed eventfs dentry creation
- * @dentry: The dentry to clean up
- *
- * If after calling eventfs_start_creating(), a failure is detected, the
- * resources created by eventfs_start_creating() needs to be cleaned up. In
- * that case, this function should be called to perform that clean up.
- */
-struct dentry *eventfs_failed_creating(struct dentry *dentry)
-{
- dput(dentry);
- simple_release_fs(&tracefs_mount, &tracefs_mount_count);
- return NULL;
-}
-
-/**
- * eventfs_end_creating - Finish the process of creating a eventfs dentry
- * @dentry: The dentry that has successfully been created.
- *
- * This function is currently just a place holder to match
- * eventfs_start_creating(). In case any synchronization needs to be added,
- * this function will be used to implement that without having to modify
- * the callers of eventfs_start_creating().
- */
-struct dentry *eventfs_end_creating(struct dentry *dentry)
-{
- return dentry;
-}
-
/* Find the inode that this will use for default */
static struct inode *instance_inode(struct dentry *parent, struct inode *inode)
{
@@ -79,9 +79,6 @@ struct dentry *tracefs_start_creating(const char *name, struct dentry *parent);
struct dentry *tracefs_end_creating(struct dentry *dentry);
struct dentry *tracefs_failed_creating(struct dentry *dentry);
struct inode *tracefs_get_inode(struct super_block *sb);
-struct dentry *eventfs_start_creating(const char *name, struct dentry *parent);
-struct dentry *eventfs_failed_creating(struct dentry *dentry);
-struct dentry *eventfs_end_creating(struct dentry *dentry);
void eventfs_set_ei_status_free(struct tracefs_inode *ti, struct dentry *dentry);
#endif /* _TRACEFS_INTERNAL_H */