diff options
Diffstat (limited to 'fs/tracefs/event_inode.c')
| -rw-r--r-- | fs/tracefs/event_inode.c | 852 |
1 files changed, 852 insertions, 0 deletions
diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c new file mode 100644 index 000000000000..9f64e7332796 --- /dev/null +++ b/fs/tracefs/event_inode.c @@ -0,0 +1,852 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * event_inode.c - part of tracefs, a pseudo file system for activating tracing + * + * Copyright (C) 2020-23 VMware Inc, author: Steven Rostedt (VMware) <[email protected]> + * Copyright (C) 2020-23 VMware Inc, author: Ajay Kaher <[email protected]> + * + * eventfs is used to dynamically create inodes and dentries based on the + * meta data provided by the tracing system. + * + * eventfs stores the meta-data of files/dirs and holds off on creating + * inodes/dentries of the files. When accessed, the eventfs will create the + * inodes/dentries in a just-in-time (JIT) manner. The eventfs will clean up + * and delete the inodes/dentries when they are no longer referenced. + */ +#include <linux/fsnotify.h> +#include <linux/fs.h> +#include <linux/namei.h> +#include <linux/workqueue.h> +#include <linux/security.h> +#include <linux/tracefs.h> +#include <linux/kref.h> +#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 + * @mode: the permission that the file or directory should have + */ +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 + * @del_list: list of eventfs_file to delete + * @rcu: eventfs_file to delete in RCU + * @is_freed: node is freed if one of the above is set + */ + union { + struct list_head del_list; + struct rcu_head rcu; + unsigned long is_freed; + }; + void *data; + umode_t mode; +}; + +static DEFINE_MUTEX(eventfs_mutex); +DEFINE_STATIC_SRCU(eventfs_srcu); + +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 eventfs_release(struct inode *inode, struct file *file); + +static const struct inode_operations eventfs_root_dir_inode_operations = { + .lookup = eventfs_root_lookup, +}; + +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, +}; + +/** + * create_file - create a file in the tracefs filesystem + * @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 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. + */ +static struct dentry *create_file(const char *name, umode_t mode, + struct dentry *parent, void *data, + const struct file_operations *fop) +{ + struct tracefs_inode *ti; + struct dentry *dentry; + struct inode *inode; + + if (!(mode & S_IFMT)) + mode |= S_IFREG; + + if (WARN_ON_ONCE(!S_ISREG(mode))) + return NULL; + + 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); + + inode->i_mode = mode; + inode->i_fop = fop; + inode->i_private = data; + + 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); +}; + +/** + * create_dir - create a dir in the tracefs filesystem + * @name: the name of the file 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. + */ +static struct dentry *create_dir(const char *name, struct dentry *parent, void *data) +{ + struct tracefs_inode *ti; + struct dentry *dentry; + struct inode *inode; + + 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); + + 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; + inode->i_private = data; + + ti = get_tracefs(inode); + ti->flags |= TRACEFS_EVENT_INODE; + + 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); +} + +/** + * 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) +{ + struct tracefs_inode *ti_parent; + struct eventfs_inode *ei; + struct eventfs_file *ef, *tmp; + + /* The top level events directory may be freed by this */ + if (unlikely(ti->flags & TRACEFS_EVENT_TOP_INODE)) { + LIST_HEAD(ef_del_list); + + mutex_lock(&eventfs_mutex); + + ei = ti->private; + + /* Record all the top level files */ + list_for_each_entry_srcu(ef, &ei->e_top_files, list, + lockdep_is_held(&eventfs_mutex)) { + list_add_tail(&ef->del_list, &ef_del_list); + } + + /* Nothing should access this, but just in case! */ + ti->private = NULL; + + mutex_unlock(&eventfs_mutex); + + /* Now safely free the top level files and their children */ + list_for_each_entry_safe(ef, tmp, &ef_del_list, del_list) { + list_del(&ef->del_list); + eventfs_remove(ef); + } + + kfree(ei); + return; + } + + mutex_lock(&eventfs_mutex); + + ti_parent = get_tracefs(dentry->d_parent->d_inode); + if (!ti_parent || !(ti_parent->flags & TRACEFS_EVENT_INODE)) + goto out; + + ef = dentry->d_fsdata; + if (!ef) + goto out; + + /* + * If ef was freed, then the LSB bit is set for d_fsdata. + * But this should not happen, as it should still have a + * ref count that prevents it. Warn in case it does. + */ + if (WARN_ON_ONCE((unsigned long)ef & 1)) + goto out; + + dentry->d_fsdata = NULL; + ef->dentry = NULL; +out: + mutex_unlock(&eventfs_mutex); +} + +/** + * eventfs_post_create_dir - post create dir routine + * @ef: eventfs_file 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_file *ef) +{ + 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; +} + +/** + * 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 + * + * Used to create a dentry for file/dir, executes post dentry creation routine + */ +static struct dentry * +create_dentry(struct eventfs_file *ef, struct dentry *parent, bool lookup) +{ + bool invalidate = false; + struct dentry *dentry; + + 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->name, parent, ef->data); + else + dentry = create_file(ef->name, ef->mode, parent, + ef->data, ef->fop); + + 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; +} + +/** + * 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 + * + * 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. + */ +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; + int idx; + + ti = get_tracefs(dir); + if (!(ti->flags & TRACEFS_EVENT_INODE)) + return NULL; + + 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)) + continue; + ret = simple_lookup(dir, dentry, flags); + create_dentry(ef, ef->d_parent, true); + break; + } + srcu_read_unlock(&eventfs_srcu, idx); + 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; + int idx; + + ti = get_tracefs(inode); + if (!(ti->flags & TRACEFS_EVENT_INODE)) + return -EINVAL; + + 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)) { + mutex_lock(&eventfs_mutex); + dentry = ef->dentry; + mutex_unlock(&eventfs_mutex); + if (dentry) + dput(dentry); + } + srcu_read_unlock(&eventfs_srcu, idx); + return dcache_dir_close(inode, file); +} + +/** + * 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. + */ +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 dentry *dentry = file_dentry(file); + struct inode *f_inode = file_inode(file); + int idx; + + ti = get_tracefs(f_inode); + if (!(ti->flags & TRACEFS_EVENT_INODE)) + return -EINVAL; + + 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)) { + create_dentry(ef, dentry, false); + } + srcu_read_unlock(&eventfs_srcu, idx); + return dcache_dir_open(inode, file); +} + +/** + * 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; + + ef = kzalloc(sizeof(*ef), GFP_KERNEL); + if (!ef) + return ERR_PTR(-ENOMEM); + + ef->name = kstrdup(name, GFP_KERNEL); + if (!ef->name) { + kfree(ef); + return ERR_PTR(-ENOMEM); + } + + 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); + } else { + ef->ei = NULL; + } + + ef->iop = iop; + ef->fop = fop; + ef->mode = mode; + ef->data = data; + return ef; +} + +/** + * 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 (security_locked_down(LOCKDOWN_TRACEFS)) + return NULL; + + if (IS_ERR(dentry)) + return dentry; + + 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); + } + + INIT_LIST_HEAD(&ei->e_top_files); + + ti = get_tracefs(inode); + ti->flags |= TRACEFS_EVENT_INODE | TRACEFS_EVENT_TOP_INODE; + ti->private = ei; + + 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; + + /* 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); +} + +/** + * 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. + * + * 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. + */ +struct eventfs_file *eventfs_add_subsystem_dir(const char *name, + struct dentry *parent) +{ + struct tracefs_inode *ti_parent; + struct eventfs_inode *ei_parent; + struct eventfs_file *ef; + + if (security_locked_down(LOCKDOWN_TRACEFS)) + return NULL; + + if (!parent) + return ERR_PTR(-EINVAL); + + ti_parent = get_tracefs(parent->d_inode); + ei_parent = ti_parent->private; + + 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, &ei_parent->e_top_files); + ef->d_parent = parent; + 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; +} + +/** + * 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 (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; + + if (security_locked_down(LOCKDOWN_TRACEFS)) + return -ENODEV; + + 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); + ef->d_parent = ef_parent->dentry; + mutex_unlock(&eventfs_mutex); + return 0; +} + +static void free_ef(struct rcu_head *head) +{ + struct eventfs_file *ef = container_of(head, struct eventfs_file, rcu); + + kfree(ef->name); + kfree(ef->ei); + kfree(ef); +} + +/** + * eventfs_remove_rec - remove eventfs dir or file from list + * @ef: eventfs_file to be removed. + * @head: to create list of eventfs_file to be deleted + * @level: to check recursion depth + * + * The helper function eventfs_remove_rec() is used to clean up and free the + * associated data from eventfs for both of the added functions. + */ +static void eventfs_remove_rec(struct eventfs_file *ef, struct list_head *head, int level) +{ + struct eventfs_file *ef_child; + + if (!ef) + return; + /* + * Check recursion depth. It should never be greater than 3: + * 0 - events/ + * 1 - events/group/ + * 2 - events/group/event/ + * 3 - events/group/event/file + */ + 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, head, level + 1); + } + } + + list_del_rcu(&ef->list); + list_add_tail(&ef->del_list, head); +} + +/** + * eventfs_remove - remove eventfs dir or file from list + * @ef: eventfs_file to be removed. + * + * This function acquire the eventfs_mutex lock and call eventfs_remove_rec() + */ +void eventfs_remove(struct eventfs_file *ef) +{ + struct eventfs_file *tmp; + LIST_HEAD(ef_del_list); + struct dentry *dentry_list = NULL; + struct dentry *dentry; + + if (!ef) + return; + + mutex_lock(&eventfs_mutex); + eventfs_remove_rec(ef, &ef_del_list, 0); + list_for_each_entry_safe(ef, tmp, &ef_del_list, del_list) { + if (ef->dentry) { + unsigned long ptr = (unsigned long)dentry_list; + + /* Keep the dentry from being freed yet */ + dget(ef->dentry); + + /* + * Paranoid: The dget() above should prevent the dentry + * from being freed and calling eventfs_set_ef_status_free(). + * But just in case, set the link list LSB pointer to 1 + * and have eventfs_set_ef_status_free() check that to + * make sure that if it does happen, it will not think + * the d_fsdata is an event_file. + * + * For this to work, no event_file should be allocated + * on a odd space, as the ef should always be allocated + * to be at least word aligned. Check for that too. + */ + WARN_ON_ONCE(ptr & 1); + + ef->dentry->d_fsdata = (void *)(ptr | 1); + dentry_list = ef->dentry; + ef->dentry = NULL; + } + call_srcu(&eventfs_srcu, &ef->rcu, free_ef); + } + mutex_unlock(&eventfs_mutex); + + while (dentry_list) { + unsigned long ptr; + + dentry = dentry_list; + ptr = (unsigned long)dentry->d_fsdata & ~1UL; + dentry_list = (struct dentry *)ptr; + dentry->d_fsdata = NULL; + d_invalidate(dentry); + mutex_lock(&eventfs_mutex); + /* dentry should now have at least a single reference */ + WARN_ONCE((int)d_count(dentry) < 1, + "dentry %p less than one reference (%d) after invalidate\n", + dentry, d_count(dentry)); + mutex_unlock(&eventfs_mutex); + dput(dentry); + } +} + +/** + * eventfs_remove_events_dir - remove eventfs dir or file from list + * @dentry: events's dentry to be removed. + * + * This function remove events main directory + */ +void eventfs_remove_events_dir(struct dentry *dentry) +{ + struct tracefs_inode *ti; + + if (!dentry || !dentry->d_inode) + return; + + ti = get_tracefs(dentry->d_inode); + if (!ti || !(ti->flags & TRACEFS_EVENT_INODE)) + return; + + d_invalidate(dentry); + dput(dentry); +} |