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-rw-r--r--fs/tracefs/event_inode.c1250
-rw-r--r--fs/tracefs/inode.c278
-rw-r--r--fs/tracefs/internal.h60
3 files changed, 751 insertions, 837 deletions
diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c
index efbdc47c74..110e8a2721 100644
--- a/fs/tracefs/event_inode.c
+++ b/fs/tracefs/event_inode.c
@@ -2,8 +2,9 @@
/*
* event_inode.c - part of tracefs, a pseudo file system for activating tracing
*
- * Copyright (C) 2020-23 VMware Inc, author: Steven Rostedt (VMware) <rostedt@goodmis.org>
+ * Copyright (C) 2020-23 VMware Inc, author: Steven Rostedt <rostedt@goodmis.org>
* Copyright (C) 2020-23 VMware Inc, author: Ajay Kaher <akaher@vmware.com>
+ * Copyright (C) 2023 Google, author: Steven Rostedt <rostedt@goodmis.org>
*
* eventfs is used to dynamically create inodes and dentries based on the
* meta data provided by the tracing system.
@@ -23,51 +24,32 @@
#include <linux/delay.h>
#include "internal.h"
-struct eventfs_inode {
- struct list_head e_top_files;
-};
-
/*
- * struct eventfs_file - hold the properties of the eventfs files and
- * directories.
- * @name: the name of the file or directory to create
- * @d_parent: holds parent's dentry
- * @dentry: once accessed holds dentry
- * @list: file or directory to be added to parent directory
- * @ei: list of files and directories within directory
- * @fop: file_operations for file or directory
- * @iop: inode_operations for file or directory
- * @data: something that the caller will want to get to later on
- * @is_freed: Flag set if the eventfs is on its way to be freed
- * @mode: the permission that the file or directory should have
- * @uid: saved uid if changed
- * @gid: saved gid if changed
+ * eventfs_mutex protects the eventfs_inode (ei) dentry. Any access
+ * to the ei->dentry must be done under this mutex and after checking
+ * if ei->is_freed is not set. When ei->is_freed is set, the dentry
+ * is on its way to being freed after the last dput() is made on it.
*/
-struct eventfs_file {
- const char *name;
- struct dentry *d_parent;
- struct dentry *dentry;
- struct list_head list;
- struct eventfs_inode *ei;
- const struct file_operations *fop;
- const struct inode_operations *iop;
- /*
- * Union - used for deletion
- * @llist: for calling dput() if needed after RCU
- * @rcu: eventfs_file to delete in RCU
- */
- union {
- struct llist_node llist;
- struct rcu_head rcu;
- };
- void *data;
- unsigned int is_freed:1;
- unsigned int mode:31;
- kuid_t uid;
- kgid_t gid;
-};
-
static DEFINE_MUTEX(eventfs_mutex);
+
+/* Choose something "unique" ;-) */
+#define EVENTFS_FILE_INODE_INO 0x12c4e37
+
+/* Just try to make something consistent and unique */
+static int eventfs_dir_ino(struct eventfs_inode *ei)
+{
+ if (!ei->ino)
+ ei->ino = get_next_ino();
+
+ return ei->ino;
+}
+
+/*
+ * The eventfs_inode (ei) itself is protected by SRCU. It is released from
+ * its parent's list and will have is_freed set (under eventfs_mutex).
+ * After the SRCU grace period is over and the last dput() is called
+ * the ei is freed.
+ */
DEFINE_STATIC_SRCU(eventfs_srcu);
/* Mode is unsigned short, use the upper bits for flags */
@@ -75,60 +57,202 @@ enum {
EVENTFS_SAVE_MODE = BIT(16),
EVENTFS_SAVE_UID = BIT(17),
EVENTFS_SAVE_GID = BIT(18),
+ EVENTFS_TOPLEVEL = BIT(19),
};
#define EVENTFS_MODE_MASK (EVENTFS_SAVE_MODE - 1)
+/*
+ * eventfs_inode reference count management.
+ *
+ * NOTE! We count only references from dentries, in the
+ * form 'dentry->d_fsdata'. There are also references from
+ * directory inodes ('ti->private'), but the dentry reference
+ * count is always a superset of the inode reference count.
+ */
+static void release_ei(struct kref *ref)
+{
+ struct eventfs_inode *ei = container_of(ref, struct eventfs_inode, kref);
+
+ WARN_ON_ONCE(!ei->is_freed);
+
+ kfree(ei->entry_attrs);
+ kfree_const(ei->name);
+ kfree_rcu(ei, rcu);
+}
+
+static inline void put_ei(struct eventfs_inode *ei)
+{
+ if (ei)
+ kref_put(&ei->kref, release_ei);
+}
+
+static inline void free_ei(struct eventfs_inode *ei)
+{
+ if (ei) {
+ ei->is_freed = 1;
+ put_ei(ei);
+ }
+}
+
+static inline struct eventfs_inode *get_ei(struct eventfs_inode *ei)
+{
+ if (ei)
+ kref_get(&ei->kref);
+ return ei;
+}
+
static struct dentry *eventfs_root_lookup(struct inode *dir,
struct dentry *dentry,
unsigned int flags);
-static int dcache_dir_open_wrapper(struct inode *inode, struct file *file);
-static int dcache_readdir_wrapper(struct file *file, struct dir_context *ctx);
-static int eventfs_release(struct inode *inode, struct file *file);
+static int eventfs_iterate(struct file *file, struct dir_context *ctx);
-static void update_attr(struct eventfs_file *ef, struct iattr *iattr)
+static void update_attr(struct eventfs_attr *attr, struct iattr *iattr)
{
unsigned int ia_valid = iattr->ia_valid;
if (ia_valid & ATTR_MODE) {
- ef->mode = (ef->mode & ~EVENTFS_MODE_MASK) |
+ attr->mode = (attr->mode & ~EVENTFS_MODE_MASK) |
(iattr->ia_mode & EVENTFS_MODE_MASK) |
EVENTFS_SAVE_MODE;
}
if (ia_valid & ATTR_UID) {
- ef->mode |= EVENTFS_SAVE_UID;
- ef->uid = iattr->ia_uid;
+ attr->mode |= EVENTFS_SAVE_UID;
+ attr->uid = iattr->ia_uid;
}
if (ia_valid & ATTR_GID) {
- ef->mode |= EVENTFS_SAVE_GID;
- ef->gid = iattr->ia_gid;
+ attr->mode |= EVENTFS_SAVE_GID;
+ attr->gid = iattr->ia_gid;
}
}
static int eventfs_set_attr(struct mnt_idmap *idmap, struct dentry *dentry,
- struct iattr *iattr)
+ struct iattr *iattr)
{
- struct eventfs_file *ef;
+ const struct eventfs_entry *entry;
+ struct eventfs_inode *ei;
+ const char *name;
int ret;
mutex_lock(&eventfs_mutex);
- ef = dentry->d_fsdata;
- if (ef && ef->is_freed) {
+ ei = dentry->d_fsdata;
+ if (ei->is_freed) {
/* Do not allow changes if the event is about to be removed. */
mutex_unlock(&eventfs_mutex);
return -ENODEV;
}
+ /* Preallocate the children mode array if necessary */
+ if (!(dentry->d_inode->i_mode & S_IFDIR)) {
+ if (!ei->entry_attrs) {
+ ei->entry_attrs = kcalloc(ei->nr_entries, sizeof(*ei->entry_attrs),
+ GFP_NOFS);
+ if (!ei->entry_attrs) {
+ ret = -ENOMEM;
+ goto out;
+ }
+ }
+ }
+
ret = simple_setattr(idmap, dentry, iattr);
- if (!ret && ef)
- update_attr(ef, iattr);
+ if (ret < 0)
+ goto out;
+
+ /*
+ * If this is a dir, then update the ei cache, only the file
+ * mode is saved in the ei->m_children, and the ownership is
+ * determined by the parent directory.
+ */
+ if (dentry->d_inode->i_mode & S_IFDIR) {
+ /*
+ * The events directory dentry is never freed, unless its
+ * part of an instance that is deleted. It's attr is the
+ * default for its child files and directories.
+ * Do not update it. It's not used for its own mode or ownership.
+ */
+ if (ei->is_events) {
+ /* But it still needs to know if it was modified */
+ if (iattr->ia_valid & ATTR_UID)
+ ei->attr.mode |= EVENTFS_SAVE_UID;
+ if (iattr->ia_valid & ATTR_GID)
+ ei->attr.mode |= EVENTFS_SAVE_GID;
+ } else {
+ update_attr(&ei->attr, iattr);
+ }
+
+ } else {
+ name = dentry->d_name.name;
+
+ for (int i = 0; i < ei->nr_entries; i++) {
+ entry = &ei->entries[i];
+ if (strcmp(name, entry->name) == 0) {
+ update_attr(&ei->entry_attrs[i], iattr);
+ break;
+ }
+ }
+ }
+ out:
mutex_unlock(&eventfs_mutex);
return ret;
}
+static void update_top_events_attr(struct eventfs_inode *ei, struct super_block *sb)
+{
+ struct inode *root;
+
+ /* Only update if the "events" was on the top level */
+ if (!ei || !(ei->attr.mode & EVENTFS_TOPLEVEL))
+ return;
+
+ /* Get the tracefs root inode. */
+ root = d_inode(sb->s_root);
+ ei->attr.uid = root->i_uid;
+ ei->attr.gid = root->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 || !(ei->attr.mode & EVENTFS_TOPLEVEL))
+ return;
+
+ update_top_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_root_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 = {
@@ -136,764 +260,548 @@ static const struct inode_operations eventfs_file_inode_operations = {
};
static const struct file_operations eventfs_file_operations = {
- .open = dcache_dir_open_wrapper,
.read = generic_read_dir,
- .iterate_shared = dcache_readdir_wrapper,
+ .iterate_shared = eventfs_iterate,
.llseek = generic_file_llseek,
- .release = eventfs_release,
};
-static void update_inode_attr(struct inode *inode, struct eventfs_file *ef)
+/* Return the evenfs_inode of the "events" directory */
+static struct eventfs_inode *eventfs_find_events(struct dentry *dentry)
+{
+ 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) {
+ ei = NULL;
+ break;
+ }
+ // Walk upwards until you find the events inode
+ } while (!ei->is_events);
+
+ update_top_events_attr(ei, dentry->d_sb);
+
+ return ei;
+}
+
+static void update_inode_attr(struct dentry *dentry, struct inode *inode,
+ struct eventfs_attr *attr, umode_t mode)
{
- inode->i_mode = ef->mode & EVENTFS_MODE_MASK;
+ struct eventfs_inode *events_ei = eventfs_find_events(dentry);
+
+ if (!events_ei)
+ return;
+
+ inode->i_mode = mode;
+ inode->i_uid = events_ei->attr.uid;
+ inode->i_gid = events_ei->attr.gid;
+
+ if (!attr)
+ return;
+
+ if (attr->mode & EVENTFS_SAVE_MODE)
+ inode->i_mode = attr->mode & EVENTFS_MODE_MASK;
- if (ef->mode & EVENTFS_SAVE_UID)
- inode->i_uid = ef->uid;
+ if (attr->mode & EVENTFS_SAVE_UID)
+ inode->i_uid = attr->uid;
- if (ef->mode & EVENTFS_SAVE_GID)
- inode->i_gid = ef->gid;
+ if (attr->mode & EVENTFS_SAVE_GID)
+ inode->i_gid = attr->gid;
}
/**
- * create_file - create a file in the tracefs filesystem
- * @ef: the eventfs_file
- * @parent: parent dentry for this file.
+ * 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
* @data: something that the caller will want to get to later on.
* @fop: struct file_operations that should be used for this file.
*
- * This is the basic "create a file" function for tracefs. It allows for a
- * wide range of flexibility in creating a file.
- *
- * This function will return a pointer to a dentry if it succeeds. This
- * pointer must be passed to the tracefs_remove() function when the file is
- * to be removed (no automatic cleanup happens if your module is unloaded,
- * you are responsible here.) If an error occurs, %NULL will be returned.
- *
- * If tracefs is not enabled in the kernel, the value -%ENODEV will be
- * returned.
+ * This function creates a dentry that represents a file in the eventsfs_inode
+ * directory. The inode.i_private pointer will point to @data in the open()
+ * call.
*/
-static struct dentry *create_file(struct eventfs_file *ef,
- struct dentry *parent, void *data,
+static struct dentry *lookup_file(struct eventfs_inode *parent_ei,
+ struct dentry *dentry,
+ umode_t mode,
+ struct eventfs_attr *attr,
+ void *data,
const struct file_operations *fop)
{
struct tracefs_inode *ti;
- struct dentry *dentry;
struct inode *inode;
- if (!(ef->mode & S_IFMT))
- ef->mode |= S_IFREG;
-
- if (WARN_ON_ONCE(!S_ISREG(ef->mode)))
- return NULL;
-
- dentry = eventfs_start_creating(ef->name, parent);
+ if (!(mode & S_IFMT))
+ mode |= S_IFREG;
- if (IS_ERR(dentry))
- return dentry;
+ if (WARN_ON_ONCE(!S_ISREG(mode)))
+ return ERR_PTR(-EIO);
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(inode, ef);
+ update_inode_attr(dentry, inode, attr, mode);
inode->i_op = &eventfs_file_inode_operations;
inode->i_fop = fop;
inode->i_private = data;
+ /* All files will have the same inode number */
+ inode->i_ino = EVENTFS_FILE_INODE_INO;
+
ti = get_tracefs(inode);
ti->flags |= TRACEFS_EVENT_INODE;
- d_instantiate(dentry, inode);
- fsnotify_create(dentry->d_parent->d_inode, dentry);
- return eventfs_end_creating(dentry);
+
+ // Files have their parent's ei as their fsdata
+ dentry->d_fsdata = get_ei(parent_ei);
+
+ d_add(dentry, inode);
+ return NULL;
};
/**
- * 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.
- * @data: something that the caller will want to get to later on.
*
- * This is the basic "create a dir" function for eventfs. It allows for a
- * wide range of flexibility in creating a dir.
- *
- * This function will return a pointer to a dentry if it succeeds. This
- * pointer must be passed to the tracefs_remove() function when the file is
- * to be removed (no automatic cleanup happens if your module is unloaded,
- * you are responsible here.) If an error occurs, %NULL will be returned.
- *
- * If tracefs is not enabled in the kernel, the value -%ENODEV will be
- * returned.
+ * This function will look up a dentry for a directory represented by
+ * a eventfs_inode.
*/
-static struct dentry *create_dir(struct eventfs_file *ef,
- struct dentry *parent, void *data)
+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(ef->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);
- update_inode_attr(inode, ef);
+ /* 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_root_dir_inode_operations;
inode->i_fop = &eventfs_file_operations;
- inode->i_private = data;
+
+ /* 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;
- inc_nlink(inode);
- d_instantiate(dentry, inode);
- inc_nlink(dentry->d_parent->d_inode);
- fsnotify_mkdir(dentry->d_parent->d_inode, dentry);
- return eventfs_end_creating(dentry);
-}
+ dentry->d_fsdata = get_ei(ei);
-static void free_ef(struct eventfs_file *ef)
-{
- kfree(ef->name);
- kfree(ef->ei);
- kfree(ef);
+ d_add(dentry, inode);
+ return NULL;
}
-/**
- * eventfs_set_ef_status_free - set the ef->status to free
- * @ti: the tracefs_inode of the dentry
- * @dentry: dentry who's status to be freed
- *
- * eventfs_set_ef_status_free will be called if no more
- * references remain
- */
-void eventfs_set_ef_status_free(struct tracefs_inode *ti, struct dentry *dentry)
+static inline struct eventfs_inode *alloc_ei(const char *name)
{
- struct eventfs_inode *ei;
- struct eventfs_file *ef;
+ struct eventfs_inode *ei = kzalloc(sizeof(*ei), GFP_KERNEL);
- /* The top level events directory may be freed by this */
- if (unlikely(ti->flags & TRACEFS_EVENT_TOP_INODE)) {
- mutex_lock(&eventfs_mutex);
- ei = ti->private;
-
- /* Nothing should access this, but just in case! */
- ti->private = NULL;
- mutex_unlock(&eventfs_mutex);
-
- ef = dentry->d_fsdata;
- if (ef)
- free_ef(ef);
- return;
- }
-
- mutex_lock(&eventfs_mutex);
-
- ef = dentry->d_fsdata;
- if (!ef)
- goto out;
+ if (!ei)
+ return NULL;
- if (ef->is_freed) {
- free_ef(ef);
- } else {
- ef->dentry = NULL;
+ ei->name = kstrdup_const(name, GFP_KERNEL);
+ if (!ei->name) {
+ kfree(ei);
+ return NULL;
}
-
- dentry->d_fsdata = NULL;
-out:
- mutex_unlock(&eventfs_mutex);
+ kref_init(&ei->kref);
+ return ei;
}
/**
- * eventfs_post_create_dir - post create dir routine
- * @ef: eventfs_file of recently created dir
+ * eventfs_d_release - dentry is going away
+ * @dentry: dentry which has the reference to remove.
*
- * Map the meta-data of files within an eventfs dir to their parent dentry
+ * Remove the association between a dentry from an eventfs_inode.
*/
-static void eventfs_post_create_dir(struct eventfs_file *ef)
+void eventfs_d_release(struct dentry *dentry)
{
- struct eventfs_file *ef_child;
- struct tracefs_inode *ti;
-
- /* srcu lock already held */
- /* fill parent-child relation */
- list_for_each_entry_srcu(ef_child, &ef->ei->e_top_files, list,
- srcu_read_lock_held(&eventfs_srcu)) {
- ef_child->d_parent = ef->dentry;
- }
-
- ti = get_tracefs(ef->dentry->d_inode);
- ti->private = ef->ei;
+ put_ei(dentry->d_fsdata);
}
/**
- * create_dentry - helper function to create dentry
- * @ef: eventfs_file of file or directory to create
- * @parent: parent dentry
- * @lookup: true if called from lookup routine
+ * 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 entry_attrs[] of the @ei
+ * @parent: The parent dentry of the created file.
+ * @name: The name of the file to create
+ * @mode: The mode of the file.
+ * @data: The data to use to set the inode of the file with on open()
+ * @fops: The fops of the file to be created.
*
- * Used to create a dentry for file/dir, executes post dentry creation routine
+ * Create a dentry for a file of an eventfs_inode @ei and place it into the
+ * address located at @e_dentry.
*/
static struct dentry *
-create_dentry(struct eventfs_file *ef, struct dentry *parent, bool lookup)
+lookup_file_dentry(struct dentry *dentry,
+ struct eventfs_inode *ei, int idx,
+ umode_t mode, void *data,
+ const struct file_operations *fops)
{
- bool invalidate = false;
- struct dentry *dentry;
+ struct eventfs_attr *attr = NULL;
- mutex_lock(&eventfs_mutex);
- if (ef->is_freed) {
- mutex_unlock(&eventfs_mutex);
- return NULL;
- }
- if (ef->dentry) {
- dentry = ef->dentry;
- /* On dir open, up the ref count */
- if (!lookup)
- dget(dentry);
- mutex_unlock(&eventfs_mutex);
- return dentry;
- }
- mutex_unlock(&eventfs_mutex);
-
- if (!lookup)
- inode_lock(parent->d_inode);
-
- if (ef->ei)
- dentry = create_dir(ef, parent, ef->data);
- else
- dentry = create_file(ef, parent, ef->data, ef->fop);
+ if (ei->entry_attrs)
+ attr = &ei->entry_attrs[idx];
- if (!lookup)
- inode_unlock(parent->d_inode);
-
- mutex_lock(&eventfs_mutex);
- if (IS_ERR_OR_NULL(dentry)) {
- /* If the ef was already updated get it */
- dentry = ef->dentry;
- if (dentry && !lookup)
- dget(dentry);
- mutex_unlock(&eventfs_mutex);
- return dentry;
- }
-
- if (!ef->dentry && !ef->is_freed) {
- ef->dentry = dentry;
- if (ef->ei)
- eventfs_post_create_dir(ef);
- dentry->d_fsdata = ef;
- } else {
- /* A race here, should try again (unless freed) */
- invalidate = true;
-
- /*
- * Should never happen unless we get here due to being freed.
- * Otherwise it means two dentries exist with the same name.
- */
- WARN_ON_ONCE(!ef->is_freed);
- }
- mutex_unlock(&eventfs_mutex);
- if (invalidate)
- d_invalidate(dentry);
-
- if (lookup || invalidate)
- dput(dentry);
-
- return invalidate ? NULL : dentry;
-}
-
-static bool match_event_file(struct eventfs_file *ef, const char *name)
-{
- bool ret;
-
- mutex_lock(&eventfs_mutex);
- ret = !ef->is_freed && strcmp(ef->name, name) == 0;
- mutex_unlock(&eventfs_mutex);
-
- return ret;
+ return lookup_file(ei, dentry, mode, attr, data, fops);
}
/**
* eventfs_root_lookup - lookup routine to create file/dir
* @dir: in which a lookup is being done
* @dentry: file/dir dentry
- * @flags: to pass as flags parameter to simple lookup
+ * @flags: Just passed to simple_lookup()
*
- * Used to create a dynamic file/dir within @dir. Use the eventfs_inode
- * list of meta data to find the information needed to create the file/dir.
+ * 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 eventfs_inode *ei_child;
struct tracefs_inode *ti;
struct eventfs_inode *ei;
- struct eventfs_file *ef;
- struct dentry *ret = NULL;
- int idx;
+ const char *name = dentry->d_name.name;
+ struct dentry *result = NULL;
ti = get_tracefs(dir);
if (!(ti->flags & TRACEFS_EVENT_INODE))
- return NULL;
+ return ERR_PTR(-EIO);
+
+ mutex_lock(&eventfs_mutex);
ei = ti->private;
- idx = srcu_read_lock(&eventfs_srcu);
- list_for_each_entry_srcu(ef, &ei->e_top_files, list,
- srcu_read_lock_held(&eventfs_srcu)) {
- if (!match_event_file(ef, dentry->d_name.name))
+ if (!ei || ei->is_freed)
+ goto out;
+
+ list_for_each_entry(ei_child, &ei->children, list) {
+ if (strcmp(ei_child->name, name) != 0)
continue;
- ret = simple_lookup(dir, dentry, flags);
- create_dentry(ef, ef->d_parent, true);
- break;
+ if (ei_child->is_freed)
+ goto out;
+ result = lookup_dir_entry(dentry, ei, ei_child);
+ goto out;
}
- srcu_read_unlock(&eventfs_srcu, idx);
- return ret;
-}
-struct dentry_list {
- void *cursor;
- struct dentry **dentries;
-};
-
-/**
- * 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 dentry_list *dlist = file->private_data;
- void *cursor;
- int i;
+ 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];
- ti = get_tracefs(inode);
- if (!(ti->flags & TRACEFS_EVENT_INODE))
- return -EINVAL;
+ if (strcmp(name, entry->name) != 0)
+ continue;
- if (WARN_ON_ONCE(!dlist))
- return -EINVAL;
+ data = ei->data;
+ if (entry->callback(name, &mode, &data, &fops) <= 0)
+ goto out;
- for (i = 0; dlist->dentries && dlist->dentries[i]; i++) {
- dput(dlist->dentries[i]);
+ result = lookup_file_dentry(dentry, ei, i, mode, data, fops);
+ goto out;
}
-
- cursor = dlist->cursor;
- kfree(dlist->dentries);
- kfree(dlist);
- file->private_data = cursor;
- return dcache_dir_close(inode, file);
+ out:
+ mutex_unlock(&eventfs_mutex);
+ return result;
}
-/**
- * dcache_dir_open_wrapper - eventfs open wrapper
- * @inode: not used
- * @file: dir to be opened (to create its child)
- *
- * Used to dynamically create the file/dir within @file. @file is really a
- * directory and all the files/dirs of the children within @file will be
- * created. If any of the files/dirs have already been created, their
- * reference count will be incremented.
+/*
+ * Walk the children of a eventfs_inode to fill in getdents().
*/
-static int dcache_dir_open_wrapper(struct inode *inode, struct file *file)
+static int eventfs_iterate(struct file *file, struct dir_context *ctx)
{
+ const struct file_operations *fops;
+ struct inode *f_inode = file_inode(file);
+ const struct eventfs_entry *entry;
+ struct eventfs_inode *ei_child;
struct tracefs_inode *ti;
struct eventfs_inode *ei;
- struct eventfs_file *ef;
- struct dentry_list *dlist;
- struct dentry **dentries = NULL;
- struct dentry *dentry = file_dentry(file);
- struct dentry *d;
- struct inode *f_inode = file_inode(file);
- int cnt = 0;
+ const char *name;
+ umode_t mode;
int idx;
- int ret;
+ int ret = -EINVAL;
+ int ino;
+ int i, r, c;
+
+ if (!dir_emit_dots(file, ctx))
+ return 0;
ti = get_tracefs(f_inode);
if (!(ti->flags & TRACEFS_EVENT_INODE))
return -EINVAL;
- if (WARN_ON_ONCE(file->private_data))
- return -EINVAL;
-
- dlist = kmalloc(sizeof(*dlist), GFP_KERNEL);
- if (!dlist)
- return -ENOMEM;
+ c = ctx->pos - 2;
- ei = ti->private;
idx = srcu_read_lock(&eventfs_srcu);
- list_for_each_entry_srcu(ef, &ei->e_top_files, list,
- srcu_read_lock_held(&eventfs_srcu)) {
- d = create_dentry(ef, dentry, false);
- if (d) {
- struct dentry **tmp;
+ mutex_lock(&eventfs_mutex);
+ ei = READ_ONCE(ti->private);
+ if (ei && ei->is_freed)
+ ei = NULL;
+ mutex_unlock(&eventfs_mutex);
- tmp = krealloc(dentries, sizeof(d) * (cnt + 2), GFP_KERNEL);
- if (!tmp)
- break;
- tmp[cnt] = d;
- tmp[cnt + 1] = NULL;
- cnt++;
- dentries = tmp;
- }
- }
- srcu_read_unlock(&eventfs_srcu, idx);
- ret = dcache_dir_open(inode, file);
+ if (!ei)
+ goto out;
/*
- * dcache_dir_open() sets file->private_data to a dentry cursor.
- * Need to save that but also save all the dentries that were
- * opened by this function.
+ * Need to create the dentries and inodes to have a consistent
+ * inode number.
*/
- dlist->cursor = file->private_data;
- dlist->dentries = dentries;
- file->private_data = dlist;
- return ret;
-}
+ ret = 0;
-/*
- * This just sets the file->private_data back to the cursor and back.
- */
-static int dcache_readdir_wrapper(struct file *file, struct dir_context *ctx)
-{
- struct dentry_list *dlist = file->private_data;
- int ret;
+ /* Start at 'c' to jump over already read entries */
+ for (i = c; i < ei->nr_entries; i++, ctx->pos++) {
+ void *cdata = ei->data;
- file->private_data = dlist->cursor;
- ret = dcache_readdir(file, ctx);
- dlist->cursor = file->private_data;
- file->private_data = dlist;
- return ret;
-}
+ entry = &ei->entries[i];
+ name = entry->name;
-/**
- * eventfs_prepare_ef - helper function to prepare eventfs_file
- * @name: the name of the file/directory to create.
- * @mode: the permission that the file should have.
- * @fop: struct file_operations that should be used for this file/directory.
- * @iop: struct inode_operations that should be used for this file/directory.
- * @data: 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.
- *
- * This function allocates and fills the eventfs_file structure.
- */
-static struct eventfs_file *eventfs_prepare_ef(const char *name, umode_t mode,
- const struct file_operations *fop,
- const struct inode_operations *iop,
- void *data)
-{
- struct eventfs_file *ef;
+ mutex_lock(&eventfs_mutex);
+ /* If ei->is_freed then just bail here, nothing more to do */
+ if (ei->is_freed) {
+ mutex_unlock(&eventfs_mutex);
+ goto out;
+ }
+ r = entry->callback(name, &mode, &cdata, &fops);
+ mutex_unlock(&eventfs_mutex);
+ if (r <= 0)
+ continue;
- ef = kzalloc(sizeof(*ef), GFP_KERNEL);
- if (!ef)
- return ERR_PTR(-ENOMEM);
+ ino = EVENTFS_FILE_INODE_INO;
- ef->name = kstrdup(name, GFP_KERNEL);
- if (!ef->name) {
- kfree(ef);
- return ERR_PTR(-ENOMEM);
+ if (!dir_emit(ctx, name, strlen(name), ino, DT_REG))
+ goto out;
}
- if (S_ISDIR(mode)) {
- ef->ei = kzalloc(sizeof(*ef->ei), GFP_KERNEL);
- if (!ef->ei) {
- kfree(ef->name);
- kfree(ef);
- return ERR_PTR(-ENOMEM);
- }
- INIT_LIST_HEAD(&ef->ei->e_top_files);
- ef->mode = S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO;
- } else {
- ef->ei = NULL;
- ef->mode = mode;
- }
+ /* Subtract the skipped entries above */
+ c -= min((unsigned int)c, (unsigned int)ei->nr_entries);
- ef->iop = iop;
- ef->fop = fop;
- ef->data = data;
- return ef;
-}
+ list_for_each_entry_srcu(ei_child, &ei->children, list,
+ srcu_read_lock_held(&eventfs_srcu)) {
-/**
- * eventfs_create_events_dir - create the trace event structure
- * @name: the name of the directory to create.
- * @parent: parent dentry for this file. This should be a directory dentry
- * if set. If this parameter is NULL, then the directory will be
- * created in the root of the tracefs filesystem.
- *
- * This function creates the top of the trace event directory.
- */
-struct dentry *eventfs_create_events_dir(const char *name,
- struct dentry *parent)
-{
- struct dentry *dentry = tracefs_start_creating(name, parent);
- struct eventfs_inode *ei;
- struct tracefs_inode *ti;
- struct inode *inode;
+ if (c > 0) {
+ c--;
+ continue;
+ }
- if (security_locked_down(LOCKDOWN_TRACEFS))
- return NULL;
+ ctx->pos++;
- if (IS_ERR(dentry))
- return dentry;
+ if (ei_child->is_freed)
+ continue;
- ei = kzalloc(sizeof(*ei), GFP_KERNEL);
- if (!ei)
- return ERR_PTR(-ENOMEM);
- inode = tracefs_get_inode(dentry->d_sb);
- if (unlikely(!inode)) {
- kfree(ei);
- tracefs_failed_creating(dentry);
- return ERR_PTR(-ENOMEM);
- }
+ name = ei_child->name;
- INIT_LIST_HEAD(&ei->e_top_files);
+ ino = eventfs_dir_ino(ei_child);
- ti = get_tracefs(inode);
- ti->flags |= TRACEFS_EVENT_INODE | TRACEFS_EVENT_TOP_INODE;
- ti->private = ei;
+ if (!dir_emit(ctx, name, strlen(name), ino, DT_DIR))
+ goto out_dec;
+ }
+ ret = 1;
+ out:
+ srcu_read_unlock(&eventfs_srcu, idx);
- inode->i_mode = S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO;
- inode->i_op = &eventfs_root_dir_inode_operations;
- inode->i_fop = &eventfs_file_operations;
+ return ret;
- /* directory inodes start off with i_nlink == 2 (for "." entry) */
- inc_nlink(inode);
- d_instantiate(dentry, inode);
- inc_nlink(dentry->d_parent->d_inode);
- fsnotify_mkdir(dentry->d_parent->d_inode, dentry);
- return tracefs_end_creating(dentry);
+ out_dec:
+ /* Incremented ctx->pos without adding something, reset it */
+ ctx->pos--;
+ goto out;
}
/**
- * eventfs_add_subsystem_dir - add eventfs subsystem_dir to list to create later
- * @name: the name of the file to create.
- * @parent: parent dentry for this dir.
+ * eventfs_create_dir - Create the eventfs_inode for this directory
+ * @name: The name of the directory to create.
+ * @parent: The eventfs_inode of the parent directory.
+ * @entries: A list of entries that represent the files under this directory
+ * @size: The number of @entries
+ * @data: The default data to pass to the files (an entry may override it).
+ *
+ * This function creates the descriptor to represent a directory in the
+ * eventfs. This descriptor is an eventfs_inode, and it is returned to be
+ * used to create other children underneath.
+ *
+ * The @entries is an array of eventfs_entry structures which has:
+ * const char *name
+ * eventfs_callback callback;
+ *
+ * The name is the name of the file, and the callback is a pointer to a function
+ * that will be called when the file is reference (either by lookup or by
+ * reading a directory). The callback is of the prototype:
+ *
+ * int callback(const char *name, umode_t *mode, void **data,
+ * const struct file_operations **fops);
+ *
+ * When a file needs to be created, this callback will be called with
+ * name = the name of the file being created (so that the same callback
+ * may be used for multiple files).
+ * mode = a place to set the file's mode
+ * data = A pointer to @data, and the callback may replace it, which will
+ * cause the file created to pass the new data to the open() call.
+ * fops = the fops to use for the created file.
*
- * This function adds eventfs subsystem dir to list.
- * And all these dirs are created on the fly when they are looked up,
- * and the dentry and inodes will be removed when they are done.
+ * NB. @callback is called while holding internal locks of the eventfs
+ * system. The callback must not call any code that might also call into
+ * the tracefs or eventfs system or it will risk creating a deadlock.
*/
-struct eventfs_file *eventfs_add_subsystem_dir(const char *name,
- struct dentry *parent)
+struct eventfs_inode *eventfs_create_dir(const char *name, struct eventfs_inode *parent,
+ const struct eventfs_entry *entries,
+ int size, void *data)
{
- struct tracefs_inode *ti_parent;
- struct eventfs_inode *ei_parent;
- struct eventfs_file *ef;
-
- if (security_locked_down(LOCKDOWN_TRACEFS))
- return NULL;
+ struct eventfs_inode *ei;
if (!parent)
return ERR_PTR(-EINVAL);
- ti_parent = get_tracefs(parent->d_inode);
- ei_parent = ti_parent->private;
+ ei = alloc_ei(name);
+ if (!ei)
+ return ERR_PTR(-ENOMEM);
- ef = eventfs_prepare_ef(name, S_IFDIR, NULL, NULL, NULL);
- if (IS_ERR(ef))
- return ef;
+ ei->entries = entries;
+ ei->nr_entries = size;
+ ei->data = data;
+ INIT_LIST_HEAD(&ei->children);
+ INIT_LIST_HEAD(&ei->list);
mutex_lock(&eventfs_mutex);
- list_add_tail(&ef->list, &ei_parent->e_top_files);
- ef->d_parent = parent;
+ if (!parent->is_freed)
+ list_add_tail(&ei->list, &parent->children);
mutex_unlock(&eventfs_mutex);
- return ef;
-}
-
-/**
- * eventfs_add_dir - add eventfs dir to list to create later
- * @name: the name of the file to create.
- * @ef_parent: parent eventfs_file for this dir.
- *
- * This function adds eventfs dir to list.
- * And all these dirs are created on the fly when they are looked up,
- * and the dentry and inodes will be removed when they are done.
- */
-struct eventfs_file *eventfs_add_dir(const char *name,
- struct eventfs_file *ef_parent)
-{
- struct eventfs_file *ef;
-
- if (security_locked_down(LOCKDOWN_TRACEFS))
- return NULL;
-
- if (!ef_parent)
- return ERR_PTR(-EINVAL);
-
- ef = eventfs_prepare_ef(name, S_IFDIR, NULL, NULL, NULL);
- if (IS_ERR(ef))
- return ef;
- mutex_lock(&eventfs_mutex);
- list_add_tail(&ef->list, &ef_parent->ei->e_top_files);
- ef->d_parent = ef_parent->dentry;
- mutex_unlock(&eventfs_mutex);
- return ef;
+ /* Was the parent freed? */
+ if (list_empty(&ei->list)) {
+ free_ei(ei);
+ ei = NULL;
+ }
+ return ei;
}
/**
- * 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.
+ * eventfs_create_events_dir - create the top level events directory
+ * @name: The name of the top level directory to create.
+ * @parent: Parent dentry for this file in the tracefs directory.
+ * @entries: A list of entries that represent the files under this directory
+ * @size: The number of @entries
+ * @data: The default data to pass to the files (an entry may override it).
*
- * 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.
+ * This function creates the top of the trace event directory.
+ *
+ * See eventfs_create_dir() for use of @entries.
*/
-int eventfs_add_events_file(const char *name, umode_t mode,
- struct dentry *parent, void *data,
- const struct file_operations *fop)
+struct eventfs_inode *eventfs_create_events_dir(const char *name, struct dentry *parent,
+ const struct eventfs_entry *entries,
+ int size, void *data)
{
- struct tracefs_inode *ti;
+ struct dentry *dentry = tracefs_start_creating(name, parent);
struct eventfs_inode *ei;
- struct eventfs_file *ef;
+ struct tracefs_inode *ti;
+ struct inode *inode;
+ kuid_t uid;
+ kgid_t gid;
if (security_locked_down(LOCKDOWN_TRACEFS))
- return -ENODEV;
-
- 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);
- ef->d_parent = parent;
- 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;
+ return NULL;
- if (security_locked_down(LOCKDOWN_TRACEFS))
- return -ENODEV;
+ if (IS_ERR(dentry))
+ return ERR_CAST(dentry);
- if (!ef_parent)
- return -EINVAL;
+ ei = alloc_ei(name);
+ if (!ei)
+ goto fail;
- if (!(mode & S_IFMT))
- mode |= S_IFREG;
+ inode = tracefs_get_inode(dentry->d_sb);
+ if (unlikely(!inode))
+ goto fail;
- ef = eventfs_prepare_ef(name, mode, fop, NULL, data);
- if (IS_ERR(ef))
- return -ENOMEM;
+ // Note: we have a ref to the dentry from tracefs_start_creating()
+ ei->events_dir = dentry;
+ ei->entries = entries;
+ ei->nr_entries = size;
+ ei->is_events = 1;
+ ei->data = data;
- mutex_lock(&eventfs_mutex);
- list_add_tail(&ef->list, &ef_parent->ei->e_top_files);
- ef->d_parent = ef_parent->dentry;
- mutex_unlock(&eventfs_mutex);
- return 0;
-}
+ /* Save the ownership of this directory */
+ uid = d_inode(dentry->d_parent)->i_uid;
+ gid = d_inode(dentry->d_parent)->i_gid;
-static LLIST_HEAD(free_list);
+ /*
+ * If the events directory is of the top instance, then parent
+ * is NULL. Set the attr.mode to reflect this and its permissions will
+ * default to the tracefs root dentry.
+ */
+ if (!parent)
+ ei->attr.mode = EVENTFS_TOPLEVEL;
-static void eventfs_workfn(struct work_struct *work)
-{
- struct eventfs_file *ef, *tmp;
- struct llist_node *llnode;
-
- llnode = llist_del_all(&free_list);
- llist_for_each_entry_safe(ef, tmp, llnode, llist) {
- /* This should only get here if it had a dentry */
- if (!WARN_ON_ONCE(!ef->dentry))
- dput(ef->dentry);
- }
-}
+ /* This is used as the default ownership of the files and directories */
+ ei->attr.uid = uid;
+ ei->attr.gid = gid;
-static DECLARE_WORK(eventfs_work, eventfs_workfn);
+ INIT_LIST_HEAD(&ei->children);
+ INIT_LIST_HEAD(&ei->list);
-static void free_rcu_ef(struct rcu_head *head)
-{
- struct eventfs_file *ef = container_of(head, struct eventfs_file, rcu);
+ ti = get_tracefs(inode);
+ ti->flags |= TRACEFS_EVENT_INODE | TRACEFS_EVENT_TOP_INODE;
+ ti->private = ei;
- if (ef->dentry) {
- /* Do not free the ef until all references of dentry are gone */
- if (llist_add(&ef->llist, &free_list))
- queue_work(system_unbound_wq, &eventfs_work);
- return;
- }
+ inode->i_mode = S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO;
+ inode->i_uid = uid;
+ inode->i_gid = gid;
+ inode->i_op = &eventfs_root_dir_inode_operations;
+ inode->i_fop = &eventfs_file_operations;
- free_ef(ef);
-}
+ dentry->d_fsdata = get_ei(ei);
-static void unhook_dentry(struct dentry *dentry)
-{
- if (!dentry)
- return;
/*
- * Need to add a reference to the dentry that is expected by
- * simple_recursive_removal(), which will include a dput().
+ * Keep all eventfs directories with i_nlink == 1.
+ * Due to the dynamic nature of the dentry creations and not
+ * wanting to add a pointer to the parent eventfs_inode in the
+ * eventfs_inode structure, keeping the i_nlink in sync with the
+ * number of directories would cause too much complexity for
+ * something not worth much. Keeping directory links at 1
+ * tells userspace not to trust the link number.
*/
- dget(dentry);
+ d_instantiate(dentry, inode);
+ /* The dentry of the "events" parent does keep track though */
+ inc_nlink(dentry->d_parent->d_inode);
+ fsnotify_mkdir(dentry->d_parent->d_inode, dentry);
+ tracefs_end_creating(dentry);
- /*
- * Also add a reference for the dput() in eventfs_workfn().
- * That is required as that dput() will free the ei after
- * the SRCU grace period is over.
- */
- dget(dentry);
+ return ei;
+
+ fail:
+ free_ei(ei);
+ tracefs_failed_creating(dentry);
+ return ERR_PTR(-ENOMEM);
}
/**
* eventfs_remove_rec - remove eventfs dir or file from list
- * @ef: eventfs_file to be removed.
- * @level: to check recursion depth
+ * @ei: eventfs_inode to be removed.
+ * @level: prevent recursion from going more than 3 levels deep.
*
- * The helper function eventfs_remove_rec() is used to clean up and free the
- * associated data from eventfs for both of the added functions.
+ * This function recursively removes eventfs_inodes which
+ * contains info of files and/or directories.
*/
-static void eventfs_remove_rec(struct eventfs_file *ef, int level)
+static void eventfs_remove_rec(struct eventfs_inode *ei, int level)
{
- struct eventfs_file *ef_child;
+ struct eventfs_inode *ei_child;
- if (!ef)
- return;
/*
* Check recursion depth. It should never be greater than 3:
* 0 - events/
@@ -904,72 +812,54 @@ static void eventfs_remove_rec(struct eventfs_file *ef, int level)
if (WARN_ON_ONCE(level > 3))
return;
- if (ef->ei) {
- /* search for nested folders or files */
- list_for_each_entry_srcu(ef_child, &ef->ei->e_top_files, list,
- lockdep_is_held(&eventfs_mutex)) {
- eventfs_remove_rec(ef_child, level + 1);
- }
- }
-
- ef->is_freed = 1;
+ /* search for nested folders or files */
+ list_for_each_entry(ei_child, &ei->children, list)
+ eventfs_remove_rec(ei_child, level + 1);
- unhook_dentry(ef->dentry);
-
- list_del_rcu(&ef->list);
- call_srcu(&eventfs_srcu, &ef->rcu, free_rcu_ef);
+ list_del(&ei->list);
+ free_ei(ei);
}
/**
- * eventfs_remove - remove eventfs dir or file from list
- * @ef: eventfs_file to be removed.
+ * eventfs_remove_dir - remove eventfs dir or file from list
+ * @ei: eventfs_inode to be removed.
*
* This function acquire the eventfs_mutex lock and call eventfs_remove_rec()
*/
-void eventfs_remove(struct eventfs_file *ef)
+void eventfs_remove_dir(struct eventfs_inode *ei)
{
- struct dentry *dentry;
-
- if (!ef)
+ if (!ei)
return;
mutex_lock(&eventfs_mutex);
- dentry = ef->dentry;
- eventfs_remove_rec(ef, 0);
+ eventfs_remove_rec(ei, 0);
mutex_unlock(&eventfs_mutex);
-
- /*
- * If any of the ei children has a dentry, then the ei itself
- * must have a dentry.
- */
- if (dentry)
- simple_recursive_removal(dentry, NULL);
}
/**
- * eventfs_remove_events_dir - remove eventfs dir or file from list
- * @dentry: events's dentry to be removed.
+ * eventfs_remove_events_dir - remove the top level eventfs directory
+ * @ei: the event_inode returned by eventfs_create_events_dir().
*
- * This function remove events main directory
+ * This function removes the events main directory
*/
-void eventfs_remove_events_dir(struct dentry *dentry)
+void eventfs_remove_events_dir(struct eventfs_inode *ei)
{
- struct eventfs_file *ef_child;
- struct eventfs_inode *ei;
- struct tracefs_inode *ti;
+ struct dentry *dentry;
- if (!dentry || !dentry->d_inode)
+ dentry = ei->events_dir;
+ if (!dentry)
return;
- ti = get_tracefs(dentry->d_inode);
- if (!ti || !(ti->flags & TRACEFS_EVENT_INODE))
- return;
+ ei->events_dir = NULL;
+ eventfs_remove_dir(ei);
- mutex_lock(&eventfs_mutex);
- ei = ti->private;
- list_for_each_entry_srcu(ef_child, &ei->e_top_files, list,
- lockdep_is_held(&eventfs_mutex)) {
- eventfs_remove_rec(ef_child, 0);
- }
- mutex_unlock(&eventfs_mutex);
+ /*
+ * Matches the dget() done by tracefs_start_creating()
+ * in eventfs_create_events_dir() when it the dentry was
+ * created. In other words, it's a normal dentry that
+ * sticks around while the other ei->dentry are created
+ * and destroyed dynamically.
+ */
+ d_invalidate(dentry);
+ dput(dentry);
}
diff --git a/fs/tracefs/inode.c b/fs/tracefs/inode.c
index 0292c6a2be..d65ffad4c3 100644
--- a/fs/tracefs/inode.c
+++ b/fs/tracefs/inode.c
@@ -38,8 +38,6 @@ static struct inode *tracefs_alloc_inode(struct super_block *sb)
if (!ti)
return NULL;
- ti->flags = 0;
-
return &ti->vfs_inode;
}
@@ -91,6 +89,7 @@ static int tracefs_syscall_mkdir(struct mnt_idmap *idmap,
struct inode *inode, struct dentry *dentry,
umode_t mode)
{
+ struct tracefs_inode *ti;
char *name;
int ret;
@@ -99,6 +98,15 @@ static int tracefs_syscall_mkdir(struct mnt_idmap *idmap,
return -ENOMEM;
/*
+ * This is a new directory that does not take the default of
+ * the rootfs. It becomes the default permissions for all the
+ * files and directories underneath it.
+ */
+ ti = get_tracefs(inode);
+ ti->flags |= TRACEFS_INSTANCE_INODE;
+ ti->private = inode;
+
+ /*
* The mkdir call can call the generic functions that create
* the files within the tracefs system. It is up to the individual
* mkdir routine to handle races.
@@ -141,10 +149,76 @@ static int tracefs_syscall_rmdir(struct inode *inode, struct dentry *dentry)
return ret;
}
-static const struct inode_operations tracefs_dir_inode_operations = {
+static void set_tracefs_inode_owner(struct inode *inode)
+{
+ struct tracefs_inode *ti = get_tracefs(inode);
+ struct inode *root_inode = ti->private;
+
+ /*
+ * If this inode has never been referenced, then update
+ * the permissions to the superblock.
+ */
+ if (!(ti->flags & TRACEFS_UID_PERM_SET))
+ inode->i_uid = root_inode->i_uid;
+
+ if (!(ti->flags & TRACEFS_GID_PERM_SET))
+ inode->i_gid = root_inode->i_gid;
+}
+
+static int tracefs_permission(struct mnt_idmap *idmap,
+ struct inode *inode, int mask)
+{
+ set_tracefs_inode_owner(inode);
+ return generic_permission(idmap, inode, mask);
+}
+
+static int tracefs_getattr(struct mnt_idmap *idmap,
+ const struct path *path, struct kstat *stat,
+ u32 request_mask, unsigned int flags)
+{
+ struct inode *inode = d_backing_inode(path->dentry);
+
+ set_tracefs_inode_owner(inode);
+ generic_fillattr(idmap, request_mask, inode, stat);
+ return 0;
+}
+
+static int tracefs_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
+ struct iattr *attr)
+{
+ unsigned int ia_valid = attr->ia_valid;
+ struct inode *inode = d_inode(dentry);
+ struct tracefs_inode *ti = get_tracefs(inode);
+
+ if (ia_valid & ATTR_UID)
+ ti->flags |= TRACEFS_UID_PERM_SET;
+
+ if (ia_valid & ATTR_GID)
+ ti->flags |= TRACEFS_GID_PERM_SET;
+
+ return simple_setattr(idmap, dentry, attr);
+}
+
+static const struct inode_operations tracefs_instance_dir_inode_operations = {
.lookup = simple_lookup,
.mkdir = tracefs_syscall_mkdir,
.rmdir = tracefs_syscall_rmdir,
+ .permission = tracefs_permission,
+ .getattr = tracefs_getattr,
+ .setattr = tracefs_setattr,
+};
+
+static const struct inode_operations tracefs_dir_inode_operations = {
+ .lookup = simple_lookup,
+ .permission = tracefs_permission,
+ .getattr = tracefs_getattr,
+ .setattr = tracefs_setattr,
+};
+
+static const struct inode_operations tracefs_file_inode_operations = {
+ .permission = tracefs_permission,
+ .getattr = tracefs_getattr,
+ .setattr = tracefs_setattr,
};
struct inode *tracefs_get_inode(struct super_block *sb)
@@ -152,7 +226,7 @@ struct inode *tracefs_get_inode(struct super_block *sb)
struct inode *inode = new_inode(sb);
if (inode) {
inode->i_ino = get_next_ino();
- inode->i_atime = inode->i_mtime = inode_set_ctime_current(inode);
+ simple_inode_init_ts(inode);
}
return inode;
}
@@ -183,77 +257,6 @@ struct tracefs_fs_info {
struct tracefs_mount_opts mount_opts;
};
-static void change_gid(struct dentry *dentry, kgid_t gid)
-{
- if (!dentry->d_inode)
- return;
- dentry->d_inode->i_gid = gid;
-}
-
-/*
- * Taken from d_walk, but without he need for handling renames.
- * Nothing can be renamed while walking the list, as tracefs
- * does not support renames. This is only called when mounting
- * or remounting the file system, to set all the files to
- * the given gid.
- */
-static void set_gid(struct dentry *parent, kgid_t gid)
-{
- struct dentry *this_parent;
- struct list_head *next;
-
- this_parent = parent;
- spin_lock(&this_parent->d_lock);
-
- change_gid(this_parent, gid);
-repeat:
- next = this_parent->d_subdirs.next;
-resume:
- while (next != &this_parent->d_subdirs) {
- struct list_head *tmp = next;
- struct dentry *dentry = list_entry(tmp, struct dentry, d_child);
- next = tmp->next;
-
- spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED);
-
- change_gid(dentry, gid);
-
- if (!list_empty(&dentry->d_subdirs)) {
- spin_unlock(&this_parent->d_lock);
- spin_release(&dentry->d_lock.dep_map, _RET_IP_);
- this_parent = dentry;
- spin_acquire(&this_parent->d_lock.dep_map, 0, 1, _RET_IP_);
- goto repeat;
- }
- spin_unlock(&dentry->d_lock);
- }
- /*
- * All done at this level ... ascend and resume the search.
- */
- rcu_read_lock();
-ascend:
- if (this_parent != parent) {
- struct dentry *child = this_parent;
- this_parent = child->d_parent;
-
- spin_unlock(&child->d_lock);
- spin_lock(&this_parent->d_lock);
-
- /* go into the first sibling still alive */
- do {
- next = child->d_child.next;
- if (next == &this_parent->d_subdirs)
- goto ascend;
- child = list_entry(next, struct dentry, d_child);
- } while (unlikely(child->d_flags & DCACHE_DENTRY_KILLED));
- rcu_read_unlock();
- goto resume;
- }
- rcu_read_unlock();
- spin_unlock(&this_parent->d_lock);
- return;
-}
-
static int tracefs_parse_options(char *data, struct tracefs_mount_opts *opts)
{
substring_t args[MAX_OPT_ARGS];
@@ -326,10 +329,8 @@ static int tracefs_apply_options(struct super_block *sb, bool remount)
if (!remount || opts->opts & BIT(Opt_uid))
inode->i_uid = opts->uid;
- if (!remount || opts->opts & BIT(Opt_gid)) {
- /* Set all the group ids to the mount option */
- set_gid(sb->s_root, opts->gid);
- }
+ if (!remount || opts->opts & BIT(Opt_gid))
+ inode->i_gid = opts->gid;
return 0;
}
@@ -376,21 +377,30 @@ static const struct super_operations tracefs_super_operations = {
.show_options = tracefs_show_options,
};
-static void tracefs_dentry_iput(struct dentry *dentry, struct inode *inode)
+/*
+ * It would be cleaner if eventfs had its own dentry ops.
+ *
+ * Note that d_revalidate is called potentially under RCU,
+ * so it can't take the eventfs mutex etc. It's fine - if
+ * we open a file just as it's marked dead, things will
+ * still work just fine, and just see the old stale case.
+ */
+static void tracefs_d_release(struct dentry *dentry)
{
- struct tracefs_inode *ti;
+ if (dentry->d_fsdata)
+ eventfs_d_release(dentry);
+}
- if (!dentry || !inode)
- return;
+static int tracefs_d_revalidate(struct dentry *dentry, unsigned int flags)
+{
+ struct eventfs_inode *ei = dentry->d_fsdata;
- ti = get_tracefs(inode);
- if (ti && ti->flags & TRACEFS_EVENT_INODE)
- eventfs_set_ef_status_free(ti, dentry);
- iput(inode);
+ return !(ei && ei->is_freed);
}
static const struct dentry_operations tracefs_dentry_operations = {
- .d_iput = tracefs_dentry_iput,
+ .d_revalidate = tracefs_d_revalidate,
+ .d_release = tracefs_d_release,
};
static int trace_fill_super(struct super_block *sb, void *data, int silent)
@@ -494,73 +504,24 @@ 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)
+/* Find the inode that this will use for default */
+static struct inode *instance_inode(struct dentry *parent, struct inode *inode)
{
- 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);
+ struct tracefs_inode *ti;
- if (unlikely(IS_DEADDIR(parent->d_inode)))
- dentry = ERR_PTR(-ENOENT);
- else
- dentry = lookup_one_len(name, parent, strlen(name));
+ /* If parent is NULL then use root inode */
+ if (!parent)
+ return d_inode(inode->i_sb->s_root);
- if (!IS_ERR(dentry) && dentry->d_inode) {
- dput(dentry);
- dentry = ERR_PTR(-EEXIST);
+ /* Find the inode that is flagged as an instance or the root inode */
+ while (!IS_ROOT(parent)) {
+ ti = get_tracefs(d_inode(parent));
+ if (ti->flags & TRACEFS_INSTANCE_INODE)
+ break;
+ parent = parent->d_parent;
}
- 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;
+ return d_inode(parent);
}
/**
@@ -593,6 +554,7 @@ struct dentry *tracefs_create_file(const char *name, umode_t mode,
struct dentry *parent, void *data,
const struct file_operations *fops)
{
+ struct tracefs_inode *ti;
struct dentry *dentry;
struct inode *inode;
@@ -611,7 +573,11 @@ struct dentry *tracefs_create_file(const char *name, umode_t mode,
if (unlikely(!inode))
return tracefs_failed_creating(dentry);
+ ti = get_tracefs(inode);
+ ti->private = instance_inode(parent, inode);
+
inode->i_mode = mode;
+ inode->i_op = &tracefs_file_inode_operations;
inode->i_fop = fops ? fops : &tracefs_file_operations;
inode->i_private = data;
inode->i_uid = d_inode(dentry->d_parent)->i_uid;
@@ -624,6 +590,7 @@ struct dentry *tracefs_create_file(const char *name, umode_t mode,
static struct dentry *__create_dir(const char *name, struct dentry *parent,
const struct inode_operations *ops)
{
+ struct tracefs_inode *ti;
struct dentry *dentry = tracefs_start_creating(name, parent);
struct inode *inode;
@@ -641,6 +608,9 @@ static struct dentry *__create_dir(const char *name, struct dentry *parent,
inode->i_uid = d_inode(dentry->d_parent)->i_uid;
inode->i_gid = d_inode(dentry->d_parent)->i_gid;
+ ti = get_tracefs(inode);
+ ti->private = instance_inode(parent, inode);
+
/* directory inodes start off with i_nlink == 2 (for "." entry) */
inc_nlink(inode);
d_instantiate(dentry, inode);
@@ -671,7 +641,7 @@ struct dentry *tracefs_create_dir(const char *name, struct dentry *parent)
if (security_locked_down(LOCKDOWN_TRACEFS))
return NULL;
- return __create_dir(name, parent, &simple_dir_inode_operations);
+ return __create_dir(name, parent, &tracefs_dir_inode_operations);
}
/**
@@ -702,7 +672,7 @@ __init struct dentry *tracefs_create_instance_dir(const char *name,
if (WARN_ON(tracefs_ops.mkdir || tracefs_ops.rmdir))
return NULL;
- dentry = __create_dir(name, parent, &tracefs_dir_inode_operations);
+ dentry = __create_dir(name, parent, &tracefs_instance_dir_inode_operations);
if (!dentry)
return NULL;
@@ -747,7 +717,11 @@ static void init_once(void *foo)
{
struct tracefs_inode *ti = (struct tracefs_inode *) foo;
+ /* inode_init_once() calls memset() on the vfs_inode portion */
inode_init_once(&ti->vfs_inode);
+
+ /* Zero out the rest */
+ memset_after(ti, 0, vfs_inode);
}
static int __init tracefs_init(void)
diff --git a/fs/tracefs/internal.h b/fs/tracefs/internal.h
index 4f2e49e219..beb3dcd0e4 100644
--- a/fs/tracefs/internal.h
+++ b/fs/tracefs/internal.h
@@ -5,12 +5,64 @@
enum {
TRACEFS_EVENT_INODE = BIT(1),
TRACEFS_EVENT_TOP_INODE = BIT(2),
+ TRACEFS_GID_PERM_SET = BIT(3),
+ TRACEFS_UID_PERM_SET = BIT(4),
+ TRACEFS_INSTANCE_INODE = BIT(5),
};
struct tracefs_inode {
+ struct inode vfs_inode;
+ /* The below gets initialized with memset_after(ti, 0, vfs_inode) */
unsigned long flags;
void *private;
- struct inode vfs_inode;
+};
+
+/*
+ * struct eventfs_attr - cache the mode and ownership of a eventfs entry
+ * @mode: saved mode plus flags of what is saved
+ * @uid: saved uid if changed
+ * @gid: saved gid if changed
+ */
+struct eventfs_attr {
+ int mode;
+ kuid_t uid;
+ kgid_t gid;
+};
+
+/*
+ * struct eventfs_inode - hold the properties of the eventfs directories.
+ * @list: link list into the parent directory
+ * @rcu: Union with @list for freeing
+ * @children: link list into the child eventfs_inode
+ * @entries: the array of entries representing the files in the directory
+ * @name: the name of the directory to create
+ * @events_dir: the dentry of the events directory
+ * @entry_attrs: Saved mode and ownership of the @d_children
+ * @data: The private data to pass to the callbacks
+ * @attr: Saved mode and ownership of eventfs_inode itself
+ * @is_freed: Flag set if the eventfs is on its way to be freed
+ * Note if is_freed is set, then dentry is corrupted.
+ * @is_events: Flag set for only the top level "events" directory
+ * @nr_entries: The number of items in @entries
+ * @ino: The saved inode number
+ */
+struct eventfs_inode {
+ union {
+ struct list_head list;
+ struct rcu_head rcu;
+ };
+ struct list_head children;
+ const struct eventfs_entry *entries;
+ const char *name;
+ struct dentry *events_dir;
+ struct eventfs_attr *entry_attrs;
+ void *data;
+ struct eventfs_attr attr;
+ struct kref kref;
+ unsigned int is_freed:1;
+ unsigned int is_events:1;
+ unsigned int nr_entries:30;
+ unsigned int ino;
};
static inline struct tracefs_inode *get_tracefs(const struct inode *inode)
@@ -22,9 +74,7 @@ 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_ef_status_free(struct tracefs_inode *ti, struct dentry *dentry);
+
+void eventfs_d_release(struct dentry *dentry);
#endif /* _TRACEFS_INTERNAL_H */