Adding eventfs_file structure which will hold properties of file or dir.

Adding following functions to add dir in eventfs:

eventfs_create_events_dir() will directly create events dir with-in tracing folder.

eventfs_add_subsystem_dir() will adds the info of subsystem_dir to eventfs and dynamically create subsystem_dir as and when requires.

eventfs_add_dir() will add the info of dir (which is with-in subsystem_dir) to eventfs and dynamically create these dir as and when requires.

Signed-off-by: Ajay Kaher akaher@vmware.com Co-developed-by: Steven Rostedt (VMware) rostedt@goodmis.org Signed-off-by: Steven Rostedt (VMware) rostedt@goodmis.org Tested-by: Ching-lin Yu chinglinyu@google.com --- fs/tracefs/Makefile | 1 + fs/tracefs/event_inode.c | 252 +++++++++++++++++++++++++++++++++++++++ include/linux/tracefs.h | 29 +++++ kernel/trace/trace.h | 1 + 4 files changed, 283 insertions(+) create mode 100644 fs/tracefs/event_inode.c

diff --git a/fs/tracefs/Makefile b/fs/tracefs/Makefile index 7c35a282b..73c56da8e 100644 --- a/fs/tracefs/Makefile +++ b/fs/tracefs/Makefile @@ -1,5 +1,6 @@ # SPDX-License-Identifier: GPL-2.0-only tracefs-objs := inode.o +tracefs-objs += event_inode.o

obj-$(CONFIG_TRACING) += tracefs.o

diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c new file mode 100644 index 000000000..82caba7e9 --- /dev/null +++ b/fs/tracefs/event_inode.c @@ -0,0 +1,252 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * event_inode.c - part of tracefs, a pseudo file system for activating tracing + * + * Copyright (C) 2020-22 VMware Inc, author: Steven Rostedt (VMware) rostedt@goodmis.org + * Copyright (C) 2020-22 VMware Inc, author: Ajay Kaher akaher@vmware.com + * + * eventfs is used to show trace events with one set of dentries + * + * eventfs stores meta-data of files/dirs and skip to create object of + * inodes/dentries. As and when requires, eventfs will create the + * inodes/dentries for only required files/directories. Also eventfs + * would delete the inodes/dentries once no more requires but preserve + * the meta data. + */ +#include <linux/fsnotify.h> +#include <linux/fs.h> +#include <linux/namei.h> +#include <linux/security.h> +#include <linux/tracefs.h> +#include <linux/kref.h> +#include <linux/delay.h> +#include "internal.h" + +/** + * eventfs_dentry_to_rwsem - Return corresponding eventfs_rwsem + * @dentry: a pointer to dentry + * + * helper function to return crossponding eventfs_rwsem for given dentry + */ +static struct rw_semaphore *eventfs_dentry_to_rwsem(struct dentry *dentry) +{ + if (S_ISDIR(dentry->d_inode->i_mode)) + return (struct rw_semaphore *)dentry->d_inode->i_private; + else + return (struct rw_semaphore *)dentry->d_parent->d_inode->i_private; +} + +/** + * eventfs_down_read - acquire read lock function + * @eventfs_rwsem: a pointer to rw_semaphore + * + * helper function to perform read lock, skip locking if caller task already + * own the lock. read lock requires for lookup(), release() and these also + * called with-in open(), remove() which already hold the read/write lock. + */ +static void eventfs_down_read(struct rw_semaphore *eventfs_rwsem) +{ + down_read_nested(eventfs_rwsem, SINGLE_DEPTH_NESTING); +} + +/** + * eventfs_up_read - release read lock function + * @eventfs_rwsem: a pointer to rw_semaphore + * + * helper function to release eventfs_rwsem lock if locked + */ +static void eventfs_up_read(struct rw_semaphore *eventfs_rwsem) +{ + up_read(eventfs_rwsem); +} + +/** + * eventfs_down_write - acquire write lock function + * @eventfs_rwsem: a pointer to rw_semaphore + * + * helper function to perform write lock on eventfs_rwsem + */ +static void eventfs_down_write(struct rw_semaphore *eventfs_rwsem) +{ + while (!down_write_trylock(eventfs_rwsem)) + msleep(10); +} + +/** + * eventfs_up_write - release write lock function + * @eventfs_rwsem: a pointer to rw_semaphore + * + * helper function to perform write lock on eventfs_rwsem + */ +static void eventfs_up_write(struct rw_semaphore *eventfs_rwsem) +{ + up_write(eventfs_rwsem); +} + +static const struct file_operations eventfs_file_operations = { +}; + +static const struct inode_operations eventfs_root_dir_inode_operations = { +}; + +/** + * eventfs_create_events_dir - create the trace event structure + * @name: a pointer to a string containing the name of the directory to + * create. + * @parent: a pointer to the parent dentry for this file. This should be a + * directory dentry if set. If this parameter is NULL, then the + * directory will be created in the root of the tracefs filesystem. + * @eventfs_rwsem: a pointer to rw_semaphore + * + * This function creates the top of the trace event directory. + */ +struct dentry *eventfs_create_events_dir(const char *name, + struct dentry *parent, + struct rw_semaphore *eventfs_rwsem) +{ + struct dentry *dentry = tracefs_start_creating(name, parent); + struct eventfs_inode *ei; + struct tracefs_inode *ti; + struct inode *inode; + + 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_rwsem(eventfs_rwsem); + INIT_LIST_HEAD(&ei->e_top_files); + + ti = get_tracefs(inode); + ti->flags |= TRACEFS_EVENT_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; + inode->i_private = eventfs_rwsem; + + /* 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: a pointer to a string containing the name of the file to create. + * @parent: a pointer to the parent dentry for this dir. + * @eventfs_rwsem: a pointer to rw_semaphore + * + * 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 rw_semaphore *eventfs_rwsem) +{ + struct tracefs_inode *ti_parent; + struct eventfs_inode *ei_parent; + struct eventfs_file *ef; + + if (!parent) + return ERR_PTR(-EINVAL); + + ti_parent = get_tracefs(parent->d_inode); + ei_parent = ti_parent->private; + + ef = kzalloc(sizeof(*ef), GFP_KERNEL); + if (!ef) + return ERR_PTR(-ENOMEM); + + ef->ei = kzalloc(sizeof(*ef->ei), GFP_KERNEL); + if (!ef->ei) { + kfree(ef); + return ERR_PTR(-ENOMEM); + } + + INIT_LIST_HEAD(&ef->ei->e_top_files); + + ef->name = kstrdup(name, GFP_KERNEL); + if (!ef->name) { + kfree(ef->ei); + kfree(ef); + return ERR_PTR(-ENOMEM); + } + + ef->mode = S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO; + ef->iop = &eventfs_root_dir_inode_operations; + ef->fop = &eventfs_file_operations; + ef->dentry = NULL; + ef->created = false; + ef->d_parent = parent; + ef->data = eventfs_rwsem; + + eventfs_down_write(eventfs_rwsem); + list_add_tail(&ef->list, &ei_parent->e_top_files); + eventfs_up_write(eventfs_rwsem); + return ef; +} + +/** + * eventfs_add_dir - add eventfs dir to list to create later + * @name: a pointer to a string containing the name of the file to create. + * @ef_parent: a pointer to the parent eventfs_file for this dir. + * @eventfs_rwsem: a pointer to rw_semaphore + * + * 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 rw_semaphore *eventfs_rwsem) +{ + struct eventfs_file *ef; + + if (!ef_parent) + return ERR_PTR(-EINVAL); + + ef = kzalloc(sizeof(*ef), GFP_KERNEL); + if (!ef) + return ERR_PTR(-ENOMEM); + + ef->ei = kzalloc(sizeof(*ef->ei), GFP_KERNEL); + if (!ef->ei) { + kfree(ef); + return ERR_PTR(-ENOMEM); + } + + INIT_LIST_HEAD(&ef->ei->e_top_files); + + ef->name = kstrdup(name, GFP_KERNEL); + if (!ef->name) { + kfree(ef->ei); + kfree(ef); + return ERR_PTR(-ENOMEM); + } + + ef->mode = S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO; + ef->iop = &eventfs_root_dir_inode_operations; + ef->fop = &eventfs_file_operations; + ef->created = false; + ef->dentry = NULL; + ef->d_parent = NULL; + ef->data = eventfs_rwsem; + + eventfs_down_write(eventfs_rwsem); + list_add_tail(&ef->list, &ef_parent->ei->e_top_files); + eventfs_up_write(eventfs_rwsem); + return ef; +} diff --git a/include/linux/tracefs.h b/include/linux/tracefs.h index 999124459..aeca6761f 100644 --- a/include/linux/tracefs.h +++ b/include/linux/tracefs.h @@ -21,6 +21,35 @@ struct file_operations;

#ifdef CONFIG_TRACING

+struct eventfs_inode { + struct list_head e_top_files; +}; + +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; + void *data; + umode_t mode; + bool created; +}; + +struct dentry *eventfs_create_events_dir(const char *name, + struct dentry *parent, + struct rw_semaphore *eventfs_rwsem); + +struct eventfs_file *eventfs_add_subsystem_dir(const char *name, + struct dentry *parent, + struct rw_semaphore *eventfs_rwsem); + +struct eventfs_file *eventfs_add_dir(const char *name, + struct eventfs_file *ef_parent, + struct rw_semaphore *eventfs_rwsem); + struct dentry *tracefs_create_file(const char *name, umode_t mode, struct dentry *parent, void *data, const struct file_operations *fops); diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 616e1aa1c..3726725c8 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -359,6 +359,7 @@ struct trace_array { struct dentry *options; struct dentry *percpu_dir; struct dentry *event_dir; + struct rw_semaphore eventfs_rwsem; struct trace_options *topts; struct list_head systems; struct list_head events;

Adding following function to eventfs to add files:

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

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

Signed-off-by: Ajay Kaher akaher@vmware.com Co-developed-by: Steven Rostedt (VMware) rostedt@goodmis.org Signed-off-by: Steven Rostedt (VMware) rostedt@goodmis.org Tested-by: Ching-lin Yu chinglinyu@google.com --- fs/tracefs/event_inode.c | 118 +++++++++++++++++++++++++++++++++++++++ include/linux/tracefs.h | 8 +++ 2 files changed, 126 insertions(+)

diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c index 82caba7e9..93134ae40 100644 --- a/fs/tracefs/event_inode.c +++ b/fs/tracefs/event_inode.c @@ -250,3 +250,121 @@ struct eventfs_file *eventfs_add_dir(const char *name, eventfs_up_write(eventfs_rwsem); return ef; } + +/** + * eventfs_add_top_file - add event top file to list to create later + * @name: a pointer to a string containing the name of the file to create. + * @mode: the permission that the file should have. + * @parent: a pointer to the parent dentry for this file. This should be a + * directory dentry if set. If this parameter is NULL, then the + * file will be created in the root of the tracefs filesystem. + * @data: a pointer to something that the caller will want to get to later + * on. The inode.i_private pointer will point to this value on + * the open() call. + * @fop: a pointer to a struct file_operations that should be used for + * this file. + * + * This function adds top files of event dir to list. + * And all these files are created on the fly when they are looked up, + * and the dentry and inodes will be removed when they are done. + */ +int eventfs_add_top_file(const char *name, umode_t mode, + struct dentry *parent, void *data, + const struct file_operations *fop) +{ + struct tracefs_inode *ti; + struct eventfs_inode *ei; + struct eventfs_file *ef; + struct rw_semaphore *eventfs_rwsem; + + if (!parent) + return -EINVAL; + + if (!(mode & S_IFMT)) + mode |= S_IFREG; + + if (!parent->d_inode) + return -EINVAL; + + ti = get_tracefs(parent->d_inode); + if (!(ti->flags & TRACEFS_EVENT_INODE)) + return -EINVAL; + + ei = ti->private; + ef = kzalloc(sizeof(*ef), GFP_KERNEL); + if (!ef) + return -ENOMEM; + + ef->name = kstrdup(name, GFP_KERNEL); + if (!ef->name) { + kfree(ef); + return -ENOMEM; + } + + ef->mode = mode; + ef->data = data; + ef->fop = fop; + ef->dentry = NULL; + ef->ei = NULL; + ef->created = false; + ef->d_parent = parent; + + eventfs_rwsem = (struct rw_semaphore *) parent->d_inode->i_private; + eventfs_down_write(eventfs_rwsem); + list_add_tail(&ef->list, &ei->e_top_files); + eventfs_up_write(eventfs_rwsem); + return 0; +} + +/** + * eventfs_add_file - add eventfs file to list to create later + * @name: a pointer to a string containing the name of the file to create. + * @mode: the permission that the file should have. + * @ef_parent: a pointer to the parent eventfs_file for this file. + * @data: a pointer to something that the caller will want to get to later + * on. The inode.i_private pointer will point to this value on + * the open() call. + * @fop: a pointer to a struct file_operations that should be used for + * this file. + * + * This function adds top files of event dir to list. + * And all these files are created on the fly when they are looked up, + * and the dentry and inodes will be removed when they are done. + */ +int eventfs_add_file(const char *name, umode_t mode, + struct eventfs_file *ef_parent, + void *data, + const struct file_operations *fop) +{ + struct eventfs_file *ef; + struct rw_semaphore *eventfs_rwsem; + + if (!ef_parent) + return -EINVAL; + + if (!(mode & S_IFMT)) + mode |= S_IFREG; + + ef = kzalloc(sizeof(*ef), GFP_KERNEL); + if (!ef) + return -ENOMEM; + + ef->name = kstrdup(name, GFP_KERNEL); + if (!ef->name) { + kfree(ef); + return -ENOMEM; + } + + ef->mode = mode; + ef->data = data; + ef->fop = fop; + ef->dentry = NULL; + ef->ei = NULL; + ef->created = false; + + eventfs_rwsem = (struct rw_semaphore *) ef_parent->data; + eventfs_down_write(eventfs_rwsem); + list_add_tail(&ef->list, &ef_parent->ei->e_top_files); + eventfs_up_write(eventfs_rwsem); + return 0; +} diff --git a/include/linux/tracefs.h b/include/linux/tracefs.h index aeca6761f..1e1780a61 100644 --- a/include/linux/tracefs.h +++ b/include/linux/tracefs.h @@ -50,6 +50,14 @@ struct eventfs_file *eventfs_add_dir(const char *name, struct eventfs_file *ef_parent, struct rw_semaphore *eventfs_rwsem);

+int eventfs_add_file(const char *name, umode_t mode, + struct eventfs_file *ef_parent, void *data, + const struct file_operations *fops); + +int eventfs_add_top_file(const char *name, umode_t mode, + struct dentry *parent, void *data, + const struct file_operations *fops); + struct dentry *tracefs_create_file(const char *name, umode_t mode, struct dentry *parent, void *data, const struct file_operations *fops);

Adding following functions to eventfs: eventfs_set_ef_status_free() eventfs_post_create_dir() eventfs_root_lookup() eventfs_release() dcache_dir_open_wrapper()

Signed-off-by: Ajay Kaher akaher@vmware.com Co-developed-by: Steven Rostedt (VMware) rostedt@goodmis.org Signed-off-by: Steven Rostedt (VMware) rostedt@goodmis.org Tested-by: Ching-lin Yu chinglinyu@google.com --- fs/tracefs/event_inode.c | 188 +++++++++++++++++++++++++++++++++++++++ include/linux/tracefs.h | 2 + 2 files changed, 190 insertions(+)

diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c index 0ee27f7c8..f047e45ed 100644 --- a/fs/tracefs/event_inode.c +++ b/fs/tracefs/event_inode.c @@ -208,10 +208,198 @@ static struct dentry *eventfs_create_dir(const char *name, umode_t mode, return eventfs_end_creating(dentry); }

+/** + * eventfs_set_ef_status_free - set the ef->status to free + * @dentry: dentry who's status to be freed + * + * eventfs_set_ef_status_free will be called if no more + * reference remains + */ +void eventfs_set_ef_status_free(struct dentry *dentry) +{ + struct tracefs_inode *ti_parent; + struct eventfs_file *ef; + + ti_parent = get_tracefs(dentry->d_parent->d_inode); + if (!ti_parent || !(ti_parent->flags & TRACEFS_EVENT_INODE)) + return; + + ef = dentry->d_fsdata; + if (!ef) + return; + ef->created = false; + ef->dentry = NULL; +} + +/** + * eventfs_post_create_dir - post create dir routine + * @ef: eventfs_file of recently created dir + * + * Files with-in eventfs dir should know dentry of parent dir + */ +static void eventfs_post_create_dir(struct eventfs_file *ef) +{ + struct eventfs_file *ef_child; + struct tracefs_inode *ti; + + eventfs_down_read((struct rw_semaphore *) ef->data); + /* fill parent-child relation */ + list_for_each_entry(ef_child, &ef->ei->e_top_files, list) { + ef_child->d_parent = ef->dentry; + } + eventfs_up_read((struct rw_semaphore *) ef->data); + + ti = get_tracefs(ef->dentry->d_inode); + ti->private = ef->ei; +} + +/** + * eventfs_root_lookup - lookup routine to create file/dir + * @dir: directory in which lookup to be done + * @dentry: file/dir dentry + * @flags: + * + * Used to create dynamic file/dir with-in @dir, search with-in ei + * list, if @dentry found go ahead and create the file/dir + */ + +static struct dentry *eventfs_root_lookup(struct inode *dir, + struct dentry *dentry, + unsigned int flags) +{ + struct tracefs_inode *ti; + struct eventfs_inode *ei; + struct eventfs_file *ef; + struct dentry *ret = NULL; + struct rw_semaphore *eventfs_rwsem; + + ti = get_tracefs(dir); + if (!(ti->flags & TRACEFS_EVENT_INODE)) + return NULL; + + ei = ti->private; + eventfs_rwsem = (struct rw_semaphore *) dir->i_private; + eventfs_down_read(eventfs_rwsem); + list_for_each_entry(ef, &ei->e_top_files, list) { + if (strcmp(ef->name, dentry->d_name.name)) + continue; + ret = simple_lookup(dir, dentry, flags); + if (ef->created) + continue; + ef->created = true; + if (ef->ei) + ef->dentry = eventfs_create_dir(ef->name, ef->mode, ef->d_parent, + ef->data, ef->fop, ef->iop); + else + ef->dentry = eventfs_create_file(ef->name, ef->mode, ef->d_parent, + ef->data, ef->fop); + + if (IS_ERR_OR_NULL(ef->dentry)) { + ef->created = false; + } else { + if (ef->ei) + eventfs_post_create_dir(ef); + ef->dentry->d_fsdata = ef; + dput(ef->dentry); + } + break; + } + eventfs_up_read(eventfs_rwsem); + return ret; +} + +/** + * eventfs_release - called to release eventfs file/dir + * @inode: inode to be released + * @file: file to be released (not used) + */ +static int eventfs_release(struct inode *inode, struct file *file) +{ + struct tracefs_inode *ti; + struct eventfs_inode *ei; + struct eventfs_file *ef; + struct dentry *dentry = file_dentry(file); + struct rw_semaphore *eventfs_rwsem; + + ti = get_tracefs(inode); + if (!(ti->flags & TRACEFS_EVENT_INODE)) + return -EINVAL; + + ei = ti->private; + eventfs_rwsem = eventfs_dentry_to_rwsem(dentry); + eventfs_down_read(eventfs_rwsem); + list_for_each_entry(ef, &ei->e_top_files, list) { + if (ef->created) + dput(ef->dentry); + } + eventfs_up_read(eventfs_rwsem); + return dcache_dir_close(inode, file); +} + +/** + * dcache_dir_open_wrapper - eventfs open wrapper + * @inode: not used + * @file: dir to be opened (to create it's child) + * + * Used to dynamic create file/dir with-in @file, all the + * file/dir will be created. If already created then reference + * will be increased + */ +static int dcache_dir_open_wrapper(struct inode *inode, struct file *file) +{ + struct tracefs_inode *ti; + struct eventfs_inode *ei; + struct eventfs_file *ef; + struct inode *f_inode = file_inode(file); + struct dentry *dentry = file_dentry(file); + struct rw_semaphore *eventfs_rwsem; + + ti = get_tracefs(f_inode); + if (!(ti->flags & TRACEFS_EVENT_INODE)) + return -EINVAL; + + ei = ti->private; + eventfs_rwsem = eventfs_dentry_to_rwsem(dentry); + eventfs_down_read(eventfs_rwsem); + list_for_each_entry(ef, &ei->e_top_files, list) { + if (ef->created) { + dget(ef->dentry); + continue; + } + + ef->created = true; + + inode_lock(dentry->d_inode); + if (ef->ei) + ef->dentry = eventfs_create_dir(ef->name, ef->mode, dentry, + ef->data, ef->fop, ef->iop); + else + ef->dentry = eventfs_create_file(ef->name, ef->mode, dentry, + ef->data, ef->fop); + inode_unlock(dentry->d_inode); + + if (IS_ERR_OR_NULL(ef->dentry)) { + ef->created = false; + } else { + if (ef->ei) + eventfs_post_create_dir(ef); + ef->dentry->d_fsdata = ef; + } + } + eventfs_up_read(eventfs_rwsem); + return dcache_dir_open(inode, file); +} + static const struct file_operations eventfs_file_operations = { + .open = dcache_dir_open_wrapper, + .read = generic_read_dir, + .iterate_shared = dcache_readdir, + .llseek = generic_file_llseek, + .release = eventfs_release, };

static const struct inode_operations eventfs_root_dir_inode_operations = { + .lookup = eventfs_root_lookup, };

/** diff --git a/include/linux/tracefs.h b/include/linux/tracefs.h index 57bfd1322..268450d60 100644 --- a/include/linux/tracefs.h +++ b/include/linux/tracefs.h @@ -68,6 +68,8 @@ void eventfs_remove(struct eventfs_file *ef);

void eventfs_remove_events_dir(struct dentry *dentry);

+void eventfs_set_ef_status_free(struct dentry *dentry); + struct dentry *tracefs_create_file(const char *name, umode_t mode, struct dentry *parent, void *data, const struct file_operations *fops);

Till now /sys/kernel/debug/tracing/events is a part of tracefs, with-in this patch creating 'events' and it's sub-dir as eventfs. Basically replacing tracefs calls with eventfs calls for 'events'.

Signed-off-by: Ajay Kaher akaher@vmware.com Co-developed-by: Steven Rostedt (VMware) rostedt@goodmis.org Signed-off-by: Steven Rostedt (VMware) rostedt@goodmis.org Tested-by: Ching-lin Yu chinglinyu@google.com --- fs/tracefs/inode.c | 18 ++++++++++ include/linux/trace_events.h | 1 + kernel/trace/trace.h | 2 +- kernel/trace/trace_events.c | 66 +++++++++++++++++++----------------- 4 files changed, 55 insertions(+), 32 deletions(-)

diff --git a/fs/tracefs/inode.c b/fs/tracefs/inode.c index 76820d3e9..a098d7153 100644 --- a/fs/tracefs/inode.c +++ b/fs/tracefs/inode.c @@ -374,6 +374,23 @@ static const struct super_operations tracefs_super_operations = { .show_options = tracefs_show_options, };

+static void tracefs_dentry_iput(struct dentry *dentry, struct inode *inode) +{ + struct tracefs_inode *ti; + + if (!dentry || !inode) + return; + + ti = get_tracefs(inode); + if (ti && ti->flags & TRACEFS_EVENT_INODE) + eventfs_set_ef_status_free(dentry); + iput(inode); +} + +static const struct dentry_operations tracefs_dentry_operations = { + .d_iput = tracefs_dentry_iput, +}; + static int trace_fill_super(struct super_block *sb, void *data, int silent) { static const struct tree_descr trace_files[] = {{""}}; @@ -396,6 +413,7 @@ static int trace_fill_super(struct super_block *sb, void *data, int silent) goto fail;

sb->s_op = &tracefs_super_operations; + sb->s_d_op = &tracefs_dentry_operations;

tracefs_apply_options(sb, false);

diff --git a/include/linux/trace_events.h b/include/linux/trace_events.h index 0e373222a..696843d46 100644 --- a/include/linux/trace_events.h +++ b/include/linux/trace_events.h @@ -635,6 +635,7 @@ struct trace_event_file { struct list_head list; struct trace_event_call *event_call; struct event_filter __rcu *filter; + struct eventfs_file *ef; struct dentry *dir; struct trace_array *tr; struct trace_subsystem_dir *system; diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 3726725c8..ee9002852 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -1308,7 +1308,7 @@ struct trace_subsystem_dir { struct list_head list; struct event_subsystem *subsystem; struct trace_array *tr; - struct dentry *entry; + struct eventfs_file *ef; int ref_count; int nr_events; }; diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c index 654ffa404..01bd3dda6 100644 --- a/kernel/trace/trace_events.c +++ b/kernel/trace/trace_events.c @@ -988,7 +988,8 @@ static void remove_subsystem(struct trace_subsystem_dir *dir) return;

if (!--dir->nr_events) { - tracefs_remove(dir->entry); + if (dir->ef) + eventfs_remove(dir->ef); list_del(&dir->list); __put_system_dir(dir); } @@ -1009,7 +1010,8 @@ static void remove_event_file_dir(struct trace_event_file *file)

tracefs_remove(dir); } - + if (file->ef) + eventfs_remove(file->ef); list_del(&file->list); remove_subsystem(file->system); free_event_filter(file->filter); @@ -2295,13 +2297,13 @@ create_new_subsystem(const char *name) return NULL; }

-static struct dentry * +static struct eventfs_file * event_subsystem_dir(struct trace_array *tr, const char *name, struct trace_event_file *file, struct dentry *parent) { struct event_subsystem *system, *iter; struct trace_subsystem_dir *dir; - struct dentry *entry; + int res;

/* First see if we did not already create this dir */ list_for_each_entry(dir, &tr->systems, list) { @@ -2309,7 +2311,7 @@ event_subsystem_dir(struct trace_array *tr, const char *name, if (strcmp(system->name, name) == 0) { dir->nr_events++; file->system = dir; - return dir->entry; + return dir->ef; } }

@@ -2333,8 +2335,8 @@ event_subsystem_dir(struct trace_array *tr, const char *name, } else __get_system(system);

- dir->entry = tracefs_create_dir(name, parent); - if (!dir->entry) { + dir->ef = eventfs_add_subsystem_dir(name, parent, &tr->eventfs_rwsem); + if (IS_ERR(dir->ef)) { pr_warn("Failed to create system directory %s\n", name); __put_system(system); goto out_free; @@ -2349,22 +2351,22 @@ event_subsystem_dir(struct trace_array *tr, const char *name, /* the ftrace system is special, do not create enable or filter files */ if (strcmp(name, "ftrace") != 0) {

- entry = tracefs_create_file("filter", TRACE_MODE_WRITE, - dir->entry, dir, + res = eventfs_add_file("filter", TRACE_MODE_WRITE, + dir->ef, dir, &ftrace_subsystem_filter_fops); - if (!entry) { + if (res) { kfree(system->filter); system->filter = NULL; pr_warn("Could not create tracefs '%s/filter' entry\n", name); }

- trace_create_file("enable", TRACE_MODE_WRITE, dir->entry, dir, + eventfs_add_file("enable", TRACE_MODE_WRITE, dir->ef, dir, &ftrace_system_enable_fops); }

list_add(&dir->list, &tr->systems);

- return dir->entry; + return dir->ef;

out_free: kfree(dir); @@ -2418,6 +2420,7 @@ event_create_dir(struct dentry *parent, struct trace_event_file *file) { struct trace_event_call *call = file->event_call; struct trace_array *tr = file->tr; + struct eventfs_file *ef_subsystem = NULL; struct dentry *d_events; const char *name; int ret; @@ -2427,26 +2430,26 @@ event_create_dir(struct dentry *parent, struct trace_event_file *file) * then the system would be called "TRACE_SYSTEM". */ if (strcmp(call->class->system, TRACE_SYSTEM) != 0) { - d_events = event_subsystem_dir(tr, call->class->system, file, parent); - if (!d_events) + ef_subsystem = event_subsystem_dir(tr, call->class->system, file, parent); + if (!ef_subsystem) return -ENOMEM; } else d_events = parent;

name = trace_event_name(call); - file->dir = tracefs_create_dir(name, d_events); - if (!file->dir) { + file->ef = eventfs_add_dir(name, ef_subsystem, &tr->eventfs_rwsem); + if (IS_ERR(file->ef)) { pr_warn("Could not create tracefs '%s' directory\n", name); return -1; }

if (call->class->reg && !(call->flags & TRACE_EVENT_FL_IGNORE_ENABLE)) - trace_create_file("enable", TRACE_MODE_WRITE, file->dir, file, + eventfs_add_file("enable", TRACE_MODE_WRITE, file->ef, file, &ftrace_enable_fops);

#ifdef CONFIG_PERF_EVENTS if (call->event.type && call->class->reg) - trace_create_file("id", TRACE_MODE_READ, file->dir, + eventfs_add_file("id", TRACE_MODE_READ, file->ef, (void *)(long)call->event.type, &ftrace_event_id_fops); #endif @@ -2462,27 +2465,27 @@ event_create_dir(struct dentry *parent, struct trace_event_file *file) * triggers or filters. */ if (!(call->flags & TRACE_EVENT_FL_IGNORE_ENABLE)) { - trace_create_file("filter", TRACE_MODE_WRITE, file->dir, + eventfs_add_file("filter", TRACE_MODE_WRITE, file->ef, file, &ftrace_event_filter_fops);

- trace_create_file("trigger", TRACE_MODE_WRITE, file->dir, + eventfs_add_file("trigger", TRACE_MODE_WRITE, file->ef, file, &event_trigger_fops); }

#ifdef CONFIG_HIST_TRIGGERS - trace_create_file("hist", TRACE_MODE_READ, file->dir, file, + eventfs_add_file("hist", TRACE_MODE_READ, file->ef, file, &event_hist_fops); #endif #ifdef CONFIG_HIST_TRIGGERS_DEBUG - trace_create_file("hist_debug", TRACE_MODE_READ, file->dir, file, + eventfs_add_file("hist_debug", TRACE_MODE_READ, file->ef, file, &event_hist_debug_fops); #endif - trace_create_file("format", TRACE_MODE_READ, file->dir, call, + eventfs_add_file("format", TRACE_MODE_READ, file->ef, call, &ftrace_event_format_fops);

#ifdef CONFIG_TRACE_EVENT_INJECT if (call->event.type && call->class->reg) - trace_create_file("inject", 0200, file->dir, file, + eventfs_add_file("inject", 0200, file->ef, file, &event_inject_fops); #endif

@@ -3635,21 +3638,22 @@ create_event_toplevel_files(struct dentry *parent, struct trace_array *tr) { struct dentry *d_events; struct dentry *entry; + int error = 0;

entry = trace_create_file("set_event", TRACE_MODE_WRITE, parent, tr, &ftrace_set_event_fops); if (!entry) return -ENOMEM;

- d_events = tracefs_create_dir("events", parent); - if (!d_events) { + d_events = eventfs_create_events_dir("events", parent, &tr->eventfs_rwsem); + if (IS_ERR(d_events)) { pr_warn("Could not create tracefs 'events' directory\n"); return -ENOMEM; }

- entry = trace_create_file("enable", TRACE_MODE_WRITE, d_events, + error = eventfs_add_top_file("enable", TRACE_MODE_WRITE, d_events, tr, &ftrace_tr_enable_fops); - if (!entry) + if (error) return -ENOMEM;

/* There are not as crucial, just warn if they are not created */ @@ -3662,11 +3666,11 @@ create_event_toplevel_files(struct dentry *parent, struct trace_array *tr) &ftrace_set_event_notrace_pid_fops);

/* ring buffer internal formats */ - trace_create_file("header_page", TRACE_MODE_READ, d_events, + eventfs_add_top_file("header_page", TRACE_MODE_READ, d_events, ring_buffer_print_page_header, &ftrace_show_header_fops);

- trace_create_file("header_event", TRACE_MODE_READ, d_events, + eventfs_add_top_file("header_event", TRACE_MODE_READ, d_events, ring_buffer_print_entry_header, &ftrace_show_header_fops);

@@ -3754,7 +3758,7 @@ int event_trace_del_tracer(struct trace_array *tr)

down_write(&trace_event_sem); __trace_remove_event_dirs(tr); - tracefs_remove(tr->event_dir); + eventfs_remove_events_dir(tr->event_dir); up_write(&trace_event_sem);

tr->event_dir = NULL;

kprobe_args_char.tc, kprobe_args_string.tc has validation check for tracefs_create_dir, for eventfs it should be eventfs_create_dir.

Signed-off-by: Ajay Kaher akaher@vmware.com Co-developed-by: Steven Rostedt (VMware) rostedt@goodmis.org Signed-off-by: Steven Rostedt (VMware) rostedt@goodmis.org Tested-by: Ching-lin Yu chinglinyu@google.com --- .../selftests/ftrace/test.d/kprobe/kprobe_args_char.tc | 4 ++-- .../selftests/ftrace/test.d/kprobe/kprobe_args_string.tc | 4 ++-- 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_args_char.tc b/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_args_char.tc index 285b4770e..523cfb645 100644 --- a/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_args_char.tc +++ b/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_args_char.tc @@ -34,14 +34,14 @@ mips*) esac

: "Test get argument (1)" -echo "p:testprobe tracefs_create_dir arg1=+0(${ARG1}):char" > kprobe_events +echo "p:testprobe eventfs_add_dir arg1=+0(${ARG1}):char" > kprobe_events echo 1 > events/kprobes/testprobe/enable echo "p:test $FUNCTION_FORK" >> kprobe_events grep -qe "testprobe.* arg1='t'" trace

echo 0 > events/kprobes/testprobe/enable : "Test get argument (2)" -echo "p:testprobe tracefs_create_dir arg1=+0(${ARG1}):char arg2=+0(${ARG1}):char[4]" > kprobe_events +echo "p:testprobe eventfs_add_dir arg1=+0(${ARG1}):char arg2=+0(${ARG1}):char[4]" > kprobe_events echo 1 > events/kprobes/testprobe/enable echo "p:test $FUNCTION_FORK" >> kprobe_events grep -qe "testprobe.* arg1='t' arg2={'t','e','s','t'}" trace diff --git a/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_args_string.tc b/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_args_string.tc index a4f8e7c53..b9f8c3f8b 100644 --- a/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_args_string.tc +++ b/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_args_string.tc @@ -37,14 +37,14 @@ loongarch*) esac

: "Test get argument (1)" -echo "p:testprobe tracefs_create_dir arg1=+0(${ARG1}):string" > kprobe_events +echo "p:testprobe eventfs_add_dir arg1=+0(${ARG1}):string" > kprobe_events echo 1 > events/kprobes/testprobe/enable echo "p:test $FUNCTION_FORK" >> kprobe_events grep -qe "testprobe.* arg1="test"" trace

echo 0 > events/kprobes/testprobe/enable : "Test get argument (2)" -echo "p:testprobe tracefs_create_dir arg1=+0(${ARG1}):string arg2=+0(${ARG1}):string" > kprobe_events +echo "p:testprobe eventfs_add_dir arg1=+0(${ARG1}):string arg2=+0(${ARG1}):string" > kprobe_events echo 1 > events/kprobes/testprobe/enable echo "p:test $FUNCTION_FORK" >> kprobe_events grep -qe "testprobe.* arg1="test" arg2="test"" trace