1d2912cb1SThomas Gleixner // SPDX-License-Identifier: GPL-2.0-only 24282d606SSteven Rostedt (Red Hat) /* 34282d606SSteven Rostedt (Red Hat) * inode.c - part of tracefs, a pseudo file system for activating tracing 44282d606SSteven Rostedt (Red Hat) * 54282d606SSteven Rostedt (Red Hat) * Based on debugfs by: Greg Kroah-Hartman <greg@kroah.com> 64282d606SSteven Rostedt (Red Hat) * 74282d606SSteven Rostedt (Red Hat) * Copyright (C) 2014 Red Hat Inc, author: Steven Rostedt <srostedt@redhat.com> 84282d606SSteven Rostedt (Red Hat) * 94282d606SSteven Rostedt (Red Hat) * tracefs is the file system that is used by the tracing infrastructure. 104282d606SSteven Rostedt (Red Hat) */ 114282d606SSteven Rostedt (Red Hat) 124282d606SSteven Rostedt (Red Hat) #include <linux/module.h> 134282d606SSteven Rostedt (Red Hat) #include <linux/fs.h> 144282d606SSteven Rostedt (Red Hat) #include <linux/mount.h> 15cc31004aSSteven Rostedt (Red Hat) #include <linux/kobject.h> 164282d606SSteven Rostedt (Red Hat) #include <linux/namei.h> 174282d606SSteven Rostedt (Red Hat) #include <linux/tracefs.h> 184282d606SSteven Rostedt (Red Hat) #include <linux/fsnotify.h> 19bf8e6021SSteven Rostedt (VMware) #include <linux/security.h> 204282d606SSteven Rostedt (Red Hat) #include <linux/seq_file.h> 214282d606SSteven Rostedt (Red Hat) #include <linux/parser.h> 224282d606SSteven Rostedt (Red Hat) #include <linux/magic.h> 234282d606SSteven Rostedt (Red Hat) #include <linux/slab.h> 244282d606SSteven Rostedt (Red Hat) 254282d606SSteven Rostedt (Red Hat) #define TRACEFS_DEFAULT_MODE 0700 264282d606SSteven Rostedt (Red Hat) 274282d606SSteven Rostedt (Red Hat) static struct vfsmount *tracefs_mount; 284282d606SSteven Rostedt (Red Hat) static int tracefs_mount_count; 294282d606SSteven Rostedt (Red Hat) static bool tracefs_registered; 304282d606SSteven Rostedt (Red Hat) 314282d606SSteven Rostedt (Red Hat) static ssize_t default_read_file(struct file *file, char __user *buf, 324282d606SSteven Rostedt (Red Hat) size_t count, loff_t *ppos) 334282d606SSteven Rostedt (Red Hat) { 344282d606SSteven Rostedt (Red Hat) return 0; 354282d606SSteven Rostedt (Red Hat) } 364282d606SSteven Rostedt (Red Hat) 374282d606SSteven Rostedt (Red Hat) static ssize_t default_write_file(struct file *file, const char __user *buf, 384282d606SSteven Rostedt (Red Hat) size_t count, loff_t *ppos) 394282d606SSteven Rostedt (Red Hat) { 404282d606SSteven Rostedt (Red Hat) return count; 414282d606SSteven Rostedt (Red Hat) } 424282d606SSteven Rostedt (Red Hat) 434282d606SSteven Rostedt (Red Hat) static const struct file_operations tracefs_file_operations = { 444282d606SSteven Rostedt (Red Hat) .read = default_read_file, 454282d606SSteven Rostedt (Red Hat) .write = default_write_file, 464282d606SSteven Rostedt (Red Hat) .open = simple_open, 474282d606SSteven Rostedt (Red Hat) .llseek = noop_llseek, 484282d606SSteven Rostedt (Red Hat) }; 494282d606SSteven Rostedt (Red Hat) 50eae47358SSteven Rostedt (Red Hat) static struct tracefs_dir_ops { 51eae47358SSteven Rostedt (Red Hat) int (*mkdir)(const char *name); 52eae47358SSteven Rostedt (Red Hat) int (*rmdir)(const char *name); 535248ee85SZubin Mithra } tracefs_ops __ro_after_init; 54eae47358SSteven Rostedt (Red Hat) 55eae47358SSteven Rostedt (Red Hat) static char *get_dname(struct dentry *dentry) 56eae47358SSteven Rostedt (Red Hat) { 57eae47358SSteven Rostedt (Red Hat) const char *dname; 58eae47358SSteven Rostedt (Red Hat) char *name; 59eae47358SSteven Rostedt (Red Hat) int len = dentry->d_name.len; 60eae47358SSteven Rostedt (Red Hat) 61eae47358SSteven Rostedt (Red Hat) dname = dentry->d_name.name; 62eae47358SSteven Rostedt (Red Hat) name = kmalloc(len + 1, GFP_KERNEL); 63eae47358SSteven Rostedt (Red Hat) if (!name) 64eae47358SSteven Rostedt (Red Hat) return NULL; 65eae47358SSteven Rostedt (Red Hat) memcpy(name, dname, len); 66eae47358SSteven Rostedt (Red Hat) name[len] = 0; 67eae47358SSteven Rostedt (Red Hat) return name; 68eae47358SSteven Rostedt (Red Hat) } 69eae47358SSteven Rostedt (Red Hat) 70c54bd91eSChristian Brauner static int tracefs_syscall_mkdir(struct mnt_idmap *idmap, 71549c7297SChristian Brauner struct inode *inode, struct dentry *dentry, 72549c7297SChristian Brauner umode_t mode) 73eae47358SSteven Rostedt (Red Hat) { 74eae47358SSteven Rostedt (Red Hat) char *name; 75eae47358SSteven Rostedt (Red Hat) int ret; 76eae47358SSteven Rostedt (Red Hat) 77eae47358SSteven Rostedt (Red Hat) name = get_dname(dentry); 78eae47358SSteven Rostedt (Red Hat) if (!name) 79eae47358SSteven Rostedt (Red Hat) return -ENOMEM; 80eae47358SSteven Rostedt (Red Hat) 81eae47358SSteven Rostedt (Red Hat) /* 82eae47358SSteven Rostedt (Red Hat) * The mkdir call can call the generic functions that create 83eae47358SSteven Rostedt (Red Hat) * the files within the tracefs system. It is up to the individual 84eae47358SSteven Rostedt (Red Hat) * mkdir routine to handle races. 85eae47358SSteven Rostedt (Red Hat) */ 865955102cSAl Viro inode_unlock(inode); 87eae47358SSteven Rostedt (Red Hat) ret = tracefs_ops.mkdir(name); 885955102cSAl Viro inode_lock(inode); 89eae47358SSteven Rostedt (Red Hat) 90eae47358SSteven Rostedt (Red Hat) kfree(name); 91eae47358SSteven Rostedt (Red Hat) 92eae47358SSteven Rostedt (Red Hat) return ret; 93eae47358SSteven Rostedt (Red Hat) } 94eae47358SSteven Rostedt (Red Hat) 95eae47358SSteven Rostedt (Red Hat) static int tracefs_syscall_rmdir(struct inode *inode, struct dentry *dentry) 96eae47358SSteven Rostedt (Red Hat) { 97eae47358SSteven Rostedt (Red Hat) char *name; 98eae47358SSteven Rostedt (Red Hat) int ret; 99eae47358SSteven Rostedt (Red Hat) 100eae47358SSteven Rostedt (Red Hat) name = get_dname(dentry); 101eae47358SSteven Rostedt (Red Hat) if (!name) 102eae47358SSteven Rostedt (Red Hat) return -ENOMEM; 103eae47358SSteven Rostedt (Red Hat) 104eae47358SSteven Rostedt (Red Hat) /* 105eae47358SSteven Rostedt (Red Hat) * The rmdir call can call the generic functions that create 106eae47358SSteven Rostedt (Red Hat) * the files within the tracefs system. It is up to the individual 107eae47358SSteven Rostedt (Red Hat) * rmdir routine to handle races. 108eae47358SSteven Rostedt (Red Hat) * This time we need to unlock not only the parent (inode) but 109eae47358SSteven Rostedt (Red Hat) * also the directory that is being deleted. 110eae47358SSteven Rostedt (Red Hat) */ 1115955102cSAl Viro inode_unlock(inode); 112ee34c52cSSteven Rostedt (VMware) inode_unlock(d_inode(dentry)); 113eae47358SSteven Rostedt (Red Hat) 114eae47358SSteven Rostedt (Red Hat) ret = tracefs_ops.rmdir(name); 115eae47358SSteven Rostedt (Red Hat) 1165955102cSAl Viro inode_lock_nested(inode, I_MUTEX_PARENT); 117ee34c52cSSteven Rostedt (VMware) inode_lock(d_inode(dentry)); 118eae47358SSteven Rostedt (Red Hat) 119eae47358SSteven Rostedt (Red Hat) kfree(name); 120eae47358SSteven Rostedt (Red Hat) 121eae47358SSteven Rostedt (Red Hat) return ret; 122eae47358SSteven Rostedt (Red Hat) } 123eae47358SSteven Rostedt (Red Hat) 124eae47358SSteven Rostedt (Red Hat) static const struct inode_operations tracefs_dir_inode_operations = { 125eae47358SSteven Rostedt (Red Hat) .lookup = simple_lookup, 126eae47358SSteven Rostedt (Red Hat) .mkdir = tracefs_syscall_mkdir, 127eae47358SSteven Rostedt (Red Hat) .rmdir = tracefs_syscall_rmdir, 128eae47358SSteven Rostedt (Red Hat) }; 129eae47358SSteven Rostedt (Red Hat) 1304282d606SSteven Rostedt (Red Hat) static struct inode *tracefs_get_inode(struct super_block *sb) 1314282d606SSteven Rostedt (Red Hat) { 1324282d606SSteven Rostedt (Red Hat) struct inode *inode = new_inode(sb); 1334282d606SSteven Rostedt (Red Hat) if (inode) { 1344282d606SSteven Rostedt (Red Hat) inode->i_ino = get_next_ino(); 135*bb9c40e6SJeff Layton inode->i_atime = inode->i_mtime = inode_set_ctime_current(inode); 1364282d606SSteven Rostedt (Red Hat) } 1374282d606SSteven Rostedt (Red Hat) return inode; 1384282d606SSteven Rostedt (Red Hat) } 1394282d606SSteven Rostedt (Red Hat) 1404282d606SSteven Rostedt (Red Hat) struct tracefs_mount_opts { 1414282d606SSteven Rostedt (Red Hat) kuid_t uid; 1424282d606SSteven Rostedt (Red Hat) kgid_t gid; 1434282d606SSteven Rostedt (Red Hat) umode_t mode; 14447311db8SBrian Norris /* Opt_* bitfield. */ 14547311db8SBrian Norris unsigned int opts; 1464282d606SSteven Rostedt (Red Hat) }; 1474282d606SSteven Rostedt (Red Hat) 1484282d606SSteven Rostedt (Red Hat) enum { 1494282d606SSteven Rostedt (Red Hat) Opt_uid, 1504282d606SSteven Rostedt (Red Hat) Opt_gid, 1514282d606SSteven Rostedt (Red Hat) Opt_mode, 1524282d606SSteven Rostedt (Red Hat) Opt_err 1534282d606SSteven Rostedt (Red Hat) }; 1544282d606SSteven Rostedt (Red Hat) 1554282d606SSteven Rostedt (Red Hat) static const match_table_t tokens = { 1564282d606SSteven Rostedt (Red Hat) {Opt_uid, "uid=%u"}, 1574282d606SSteven Rostedt (Red Hat) {Opt_gid, "gid=%u"}, 1584282d606SSteven Rostedt (Red Hat) {Opt_mode, "mode=%o"}, 1594282d606SSteven Rostedt (Red Hat) {Opt_err, NULL} 1604282d606SSteven Rostedt (Red Hat) }; 1614282d606SSteven Rostedt (Red Hat) 1624282d606SSteven Rostedt (Red Hat) struct tracefs_fs_info { 1634282d606SSteven Rostedt (Red Hat) struct tracefs_mount_opts mount_opts; 1644282d606SSteven Rostedt (Red Hat) }; 1654282d606SSteven Rostedt (Red Hat) 16648b27b6bSSteven Rostedt (VMware) static void change_gid(struct dentry *dentry, kgid_t gid) 16748b27b6bSSteven Rostedt (VMware) { 16848b27b6bSSteven Rostedt (VMware) if (!dentry->d_inode) 16948b27b6bSSteven Rostedt (VMware) return; 17048b27b6bSSteven Rostedt (VMware) dentry->d_inode->i_gid = gid; 17148b27b6bSSteven Rostedt (VMware) } 17248b27b6bSSteven Rostedt (VMware) 17348b27b6bSSteven Rostedt (VMware) /* 17448b27b6bSSteven Rostedt (VMware) * Taken from d_walk, but without he need for handling renames. 17548b27b6bSSteven Rostedt (VMware) * Nothing can be renamed while walking the list, as tracefs 17648b27b6bSSteven Rostedt (VMware) * does not support renames. This is only called when mounting 17748b27b6bSSteven Rostedt (VMware) * or remounting the file system, to set all the files to 17848b27b6bSSteven Rostedt (VMware) * the given gid. 17948b27b6bSSteven Rostedt (VMware) */ 18048b27b6bSSteven Rostedt (VMware) static void set_gid(struct dentry *parent, kgid_t gid) 18148b27b6bSSteven Rostedt (VMware) { 18248b27b6bSSteven Rostedt (VMware) struct dentry *this_parent; 18348b27b6bSSteven Rostedt (VMware) struct list_head *next; 18448b27b6bSSteven Rostedt (VMware) 18548b27b6bSSteven Rostedt (VMware) this_parent = parent; 18648b27b6bSSteven Rostedt (VMware) spin_lock(&this_parent->d_lock); 18748b27b6bSSteven Rostedt (VMware) 18848b27b6bSSteven Rostedt (VMware) change_gid(this_parent, gid); 18948b27b6bSSteven Rostedt (VMware) repeat: 19048b27b6bSSteven Rostedt (VMware) next = this_parent->d_subdirs.next; 19148b27b6bSSteven Rostedt (VMware) resume: 19248b27b6bSSteven Rostedt (VMware) while (next != &this_parent->d_subdirs) { 19348b27b6bSSteven Rostedt (VMware) struct list_head *tmp = next; 19448b27b6bSSteven Rostedt (VMware) struct dentry *dentry = list_entry(tmp, struct dentry, d_child); 19548b27b6bSSteven Rostedt (VMware) next = tmp->next; 19648b27b6bSSteven Rostedt (VMware) 19748b27b6bSSteven Rostedt (VMware) spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED); 19848b27b6bSSteven Rostedt (VMware) 19948b27b6bSSteven Rostedt (VMware) change_gid(dentry, gid); 20048b27b6bSSteven Rostedt (VMware) 20148b27b6bSSteven Rostedt (VMware) if (!list_empty(&dentry->d_subdirs)) { 20248b27b6bSSteven Rostedt (VMware) spin_unlock(&this_parent->d_lock); 20348b27b6bSSteven Rostedt (VMware) spin_release(&dentry->d_lock.dep_map, _RET_IP_); 20448b27b6bSSteven Rostedt (VMware) this_parent = dentry; 20548b27b6bSSteven Rostedt (VMware) spin_acquire(&this_parent->d_lock.dep_map, 0, 1, _RET_IP_); 20648b27b6bSSteven Rostedt (VMware) goto repeat; 20748b27b6bSSteven Rostedt (VMware) } 20848b27b6bSSteven Rostedt (VMware) spin_unlock(&dentry->d_lock); 20948b27b6bSSteven Rostedt (VMware) } 21048b27b6bSSteven Rostedt (VMware) /* 21148b27b6bSSteven Rostedt (VMware) * All done at this level ... ascend and resume the search. 21248b27b6bSSteven Rostedt (VMware) */ 21348b27b6bSSteven Rostedt (VMware) rcu_read_lock(); 21448b27b6bSSteven Rostedt (VMware) ascend: 21548b27b6bSSteven Rostedt (VMware) if (this_parent != parent) { 21648b27b6bSSteven Rostedt (VMware) struct dentry *child = this_parent; 21748b27b6bSSteven Rostedt (VMware) this_parent = child->d_parent; 21848b27b6bSSteven Rostedt (VMware) 21948b27b6bSSteven Rostedt (VMware) spin_unlock(&child->d_lock); 22048b27b6bSSteven Rostedt (VMware) spin_lock(&this_parent->d_lock); 22148b27b6bSSteven Rostedt (VMware) 22248b27b6bSSteven Rostedt (VMware) /* go into the first sibling still alive */ 22348b27b6bSSteven Rostedt (VMware) do { 22448b27b6bSSteven Rostedt (VMware) next = child->d_child.next; 22548b27b6bSSteven Rostedt (VMware) if (next == &this_parent->d_subdirs) 22648b27b6bSSteven Rostedt (VMware) goto ascend; 22748b27b6bSSteven Rostedt (VMware) child = list_entry(next, struct dentry, d_child); 22848b27b6bSSteven Rostedt (VMware) } while (unlikely(child->d_flags & DCACHE_DENTRY_KILLED)); 22948b27b6bSSteven Rostedt (VMware) rcu_read_unlock(); 23048b27b6bSSteven Rostedt (VMware) goto resume; 23148b27b6bSSteven Rostedt (VMware) } 23248b27b6bSSteven Rostedt (VMware) rcu_read_unlock(); 23348b27b6bSSteven Rostedt (VMware) spin_unlock(&this_parent->d_lock); 23448b27b6bSSteven Rostedt (VMware) return; 23548b27b6bSSteven Rostedt (VMware) } 23648b27b6bSSteven Rostedt (VMware) 2374282d606SSteven Rostedt (Red Hat) static int tracefs_parse_options(char *data, struct tracefs_mount_opts *opts) 2384282d606SSteven Rostedt (Red Hat) { 2394282d606SSteven Rostedt (Red Hat) substring_t args[MAX_OPT_ARGS]; 2404282d606SSteven Rostedt (Red Hat) int option; 2414282d606SSteven Rostedt (Red Hat) int token; 2424282d606SSteven Rostedt (Red Hat) kuid_t uid; 2434282d606SSteven Rostedt (Red Hat) kgid_t gid; 2444282d606SSteven Rostedt (Red Hat) char *p; 2454282d606SSteven Rostedt (Red Hat) 24647311db8SBrian Norris opts->opts = 0; 2474282d606SSteven Rostedt (Red Hat) opts->mode = TRACEFS_DEFAULT_MODE; 2484282d606SSteven Rostedt (Red Hat) 2494282d606SSteven Rostedt (Red Hat) while ((p = strsep(&data, ",")) != NULL) { 2504282d606SSteven Rostedt (Red Hat) if (!*p) 2514282d606SSteven Rostedt (Red Hat) continue; 2524282d606SSteven Rostedt (Red Hat) 2534282d606SSteven Rostedt (Red Hat) token = match_token(p, tokens, args); 2544282d606SSteven Rostedt (Red Hat) switch (token) { 2554282d606SSteven Rostedt (Red Hat) case Opt_uid: 2564282d606SSteven Rostedt (Red Hat) if (match_int(&args[0], &option)) 2574282d606SSteven Rostedt (Red Hat) return -EINVAL; 2584282d606SSteven Rostedt (Red Hat) uid = make_kuid(current_user_ns(), option); 2594282d606SSteven Rostedt (Red Hat) if (!uid_valid(uid)) 2604282d606SSteven Rostedt (Red Hat) return -EINVAL; 2614282d606SSteven Rostedt (Red Hat) opts->uid = uid; 2624282d606SSteven Rostedt (Red Hat) break; 2634282d606SSteven Rostedt (Red Hat) case Opt_gid: 2644282d606SSteven Rostedt (Red Hat) if (match_int(&args[0], &option)) 2654282d606SSteven Rostedt (Red Hat) return -EINVAL; 2664282d606SSteven Rostedt (Red Hat) gid = make_kgid(current_user_ns(), option); 2674282d606SSteven Rostedt (Red Hat) if (!gid_valid(gid)) 2684282d606SSteven Rostedt (Red Hat) return -EINVAL; 2694282d606SSteven Rostedt (Red Hat) opts->gid = gid; 2704282d606SSteven Rostedt (Red Hat) break; 2714282d606SSteven Rostedt (Red Hat) case Opt_mode: 2724282d606SSteven Rostedt (Red Hat) if (match_octal(&args[0], &option)) 2734282d606SSteven Rostedt (Red Hat) return -EINVAL; 2744282d606SSteven Rostedt (Red Hat) opts->mode = option & S_IALLUGO; 2754282d606SSteven Rostedt (Red Hat) break; 2764282d606SSteven Rostedt (Red Hat) /* 2774282d606SSteven Rostedt (Red Hat) * We might like to report bad mount options here; 2784282d606SSteven Rostedt (Red Hat) * but traditionally tracefs has ignored all mount options 2794282d606SSteven Rostedt (Red Hat) */ 2804282d606SSteven Rostedt (Red Hat) } 28147311db8SBrian Norris 28247311db8SBrian Norris opts->opts |= BIT(token); 2834282d606SSteven Rostedt (Red Hat) } 2844282d606SSteven Rostedt (Red Hat) 2854282d606SSteven Rostedt (Red Hat) return 0; 2864282d606SSteven Rostedt (Red Hat) } 2874282d606SSteven Rostedt (Red Hat) 28847311db8SBrian Norris static int tracefs_apply_options(struct super_block *sb, bool remount) 2894282d606SSteven Rostedt (Red Hat) { 2904282d606SSteven Rostedt (Red Hat) struct tracefs_fs_info *fsi = sb->s_fs_info; 291ee34c52cSSteven Rostedt (VMware) struct inode *inode = d_inode(sb->s_root); 2924282d606SSteven Rostedt (Red Hat) struct tracefs_mount_opts *opts = &fsi->mount_opts; 2934282d606SSteven Rostedt (Red Hat) 29447311db8SBrian Norris /* 29547311db8SBrian Norris * On remount, only reset mode/uid/gid if they were provided as mount 29647311db8SBrian Norris * options. 29747311db8SBrian Norris */ 29847311db8SBrian Norris 29947311db8SBrian Norris if (!remount || opts->opts & BIT(Opt_mode)) { 3004282d606SSteven Rostedt (Red Hat) inode->i_mode &= ~S_IALLUGO; 3014282d606SSteven Rostedt (Red Hat) inode->i_mode |= opts->mode; 30247311db8SBrian Norris } 3034282d606SSteven Rostedt (Red Hat) 30447311db8SBrian Norris if (!remount || opts->opts & BIT(Opt_uid)) 3054282d606SSteven Rostedt (Red Hat) inode->i_uid = opts->uid; 306851e99ebSSteven Rostedt (Google) 30747311db8SBrian Norris if (!remount || opts->opts & BIT(Opt_gid)) { 308851e99ebSSteven Rostedt (Google) /* Set all the group ids to the mount option */ 309851e99ebSSteven Rostedt (Google) set_gid(sb->s_root, opts->gid); 31047311db8SBrian Norris } 3114282d606SSteven Rostedt (Red Hat) 3124282d606SSteven Rostedt (Red Hat) return 0; 3134282d606SSteven Rostedt (Red Hat) } 3144282d606SSteven Rostedt (Red Hat) 3154282d606SSteven Rostedt (Red Hat) static int tracefs_remount(struct super_block *sb, int *flags, char *data) 3164282d606SSteven Rostedt (Red Hat) { 3174282d606SSteven Rostedt (Red Hat) int err; 3184282d606SSteven Rostedt (Red Hat) struct tracefs_fs_info *fsi = sb->s_fs_info; 3194282d606SSteven Rostedt (Red Hat) 3204282d606SSteven Rostedt (Red Hat) sync_filesystem(sb); 3214282d606SSteven Rostedt (Red Hat) err = tracefs_parse_options(data, &fsi->mount_opts); 3224282d606SSteven Rostedt (Red Hat) if (err) 3234282d606SSteven Rostedt (Red Hat) goto fail; 3244282d606SSteven Rostedt (Red Hat) 32547311db8SBrian Norris tracefs_apply_options(sb, true); 3264282d606SSteven Rostedt (Red Hat) 3274282d606SSteven Rostedt (Red Hat) fail: 3284282d606SSteven Rostedt (Red Hat) return err; 3294282d606SSteven Rostedt (Red Hat) } 3304282d606SSteven Rostedt (Red Hat) 3314282d606SSteven Rostedt (Red Hat) static int tracefs_show_options(struct seq_file *m, struct dentry *root) 3324282d606SSteven Rostedt (Red Hat) { 3334282d606SSteven Rostedt (Red Hat) struct tracefs_fs_info *fsi = root->d_sb->s_fs_info; 3344282d606SSteven Rostedt (Red Hat) struct tracefs_mount_opts *opts = &fsi->mount_opts; 3354282d606SSteven Rostedt (Red Hat) 3364282d606SSteven Rostedt (Red Hat) if (!uid_eq(opts->uid, GLOBAL_ROOT_UID)) 3374282d606SSteven Rostedt (Red Hat) seq_printf(m, ",uid=%u", 3384282d606SSteven Rostedt (Red Hat) from_kuid_munged(&init_user_ns, opts->uid)); 3394282d606SSteven Rostedt (Red Hat) if (!gid_eq(opts->gid, GLOBAL_ROOT_GID)) 3404282d606SSteven Rostedt (Red Hat) seq_printf(m, ",gid=%u", 3414282d606SSteven Rostedt (Red Hat) from_kgid_munged(&init_user_ns, opts->gid)); 3424282d606SSteven Rostedt (Red Hat) if (opts->mode != TRACEFS_DEFAULT_MODE) 3434282d606SSteven Rostedt (Red Hat) seq_printf(m, ",mode=%o", opts->mode); 3444282d606SSteven Rostedt (Red Hat) 3454282d606SSteven Rostedt (Red Hat) return 0; 3464282d606SSteven Rostedt (Red Hat) } 3474282d606SSteven Rostedt (Red Hat) 3484282d606SSteven Rostedt (Red Hat) static const struct super_operations tracefs_super_operations = { 3494282d606SSteven Rostedt (Red Hat) .statfs = simple_statfs, 3504282d606SSteven Rostedt (Red Hat) .remount_fs = tracefs_remount, 3514282d606SSteven Rostedt (Red Hat) .show_options = tracefs_show_options, 3524282d606SSteven Rostedt (Red Hat) }; 3534282d606SSteven Rostedt (Red Hat) 3544282d606SSteven Rostedt (Red Hat) static int trace_fill_super(struct super_block *sb, void *data, int silent) 3554282d606SSteven Rostedt (Red Hat) { 356cda37124SEric Biggers static const struct tree_descr trace_files[] = {{""}}; 3574282d606SSteven Rostedt (Red Hat) struct tracefs_fs_info *fsi; 3584282d606SSteven Rostedt (Red Hat) int err; 3594282d606SSteven Rostedt (Red Hat) 3604282d606SSteven Rostedt (Red Hat) fsi = kzalloc(sizeof(struct tracefs_fs_info), GFP_KERNEL); 3614282d606SSteven Rostedt (Red Hat) sb->s_fs_info = fsi; 3624282d606SSteven Rostedt (Red Hat) if (!fsi) { 3634282d606SSteven Rostedt (Red Hat) err = -ENOMEM; 3644282d606SSteven Rostedt (Red Hat) goto fail; 3654282d606SSteven Rostedt (Red Hat) } 3664282d606SSteven Rostedt (Red Hat) 3674282d606SSteven Rostedt (Red Hat) err = tracefs_parse_options(data, &fsi->mount_opts); 3684282d606SSteven Rostedt (Red Hat) if (err) 3694282d606SSteven Rostedt (Red Hat) goto fail; 3704282d606SSteven Rostedt (Red Hat) 3714282d606SSteven Rostedt (Red Hat) err = simple_fill_super(sb, TRACEFS_MAGIC, trace_files); 3724282d606SSteven Rostedt (Red Hat) if (err) 3734282d606SSteven Rostedt (Red Hat) goto fail; 3744282d606SSteven Rostedt (Red Hat) 3754282d606SSteven Rostedt (Red Hat) sb->s_op = &tracefs_super_operations; 3764282d606SSteven Rostedt (Red Hat) 37747311db8SBrian Norris tracefs_apply_options(sb, false); 3784282d606SSteven Rostedt (Red Hat) 3794282d606SSteven Rostedt (Red Hat) return 0; 3804282d606SSteven Rostedt (Red Hat) 3814282d606SSteven Rostedt (Red Hat) fail: 3824282d606SSteven Rostedt (Red Hat) kfree(fsi); 3834282d606SSteven Rostedt (Red Hat) sb->s_fs_info = NULL; 3844282d606SSteven Rostedt (Red Hat) return err; 3854282d606SSteven Rostedt (Red Hat) } 3864282d606SSteven Rostedt (Red Hat) 3874282d606SSteven Rostedt (Red Hat) static struct dentry *trace_mount(struct file_system_type *fs_type, 3884282d606SSteven Rostedt (Red Hat) int flags, const char *dev_name, 3894282d606SSteven Rostedt (Red Hat) void *data) 3904282d606SSteven Rostedt (Red Hat) { 3914282d606SSteven Rostedt (Red Hat) return mount_single(fs_type, flags, data, trace_fill_super); 3924282d606SSteven Rostedt (Red Hat) } 3934282d606SSteven Rostedt (Red Hat) 3944282d606SSteven Rostedt (Red Hat) static struct file_system_type trace_fs_type = { 3954282d606SSteven Rostedt (Red Hat) .owner = THIS_MODULE, 3964282d606SSteven Rostedt (Red Hat) .name = "tracefs", 3974282d606SSteven Rostedt (Red Hat) .mount = trace_mount, 3984282d606SSteven Rostedt (Red Hat) .kill_sb = kill_litter_super, 3994282d606SSteven Rostedt (Red Hat) }; 4004282d606SSteven Rostedt (Red Hat) MODULE_ALIAS_FS("tracefs"); 4014282d606SSteven Rostedt (Red Hat) 4024282d606SSteven Rostedt (Red Hat) static struct dentry *start_creating(const char *name, struct dentry *parent) 4034282d606SSteven Rostedt (Red Hat) { 4044282d606SSteven Rostedt (Red Hat) struct dentry *dentry; 4054282d606SSteven Rostedt (Red Hat) int error; 4064282d606SSteven Rostedt (Red Hat) 4074282d606SSteven Rostedt (Red Hat) pr_debug("tracefs: creating file '%s'\n",name); 4084282d606SSteven Rostedt (Red Hat) 4094282d606SSteven Rostedt (Red Hat) error = simple_pin_fs(&trace_fs_type, &tracefs_mount, 4104282d606SSteven Rostedt (Red Hat) &tracefs_mount_count); 4114282d606SSteven Rostedt (Red Hat) if (error) 4124282d606SSteven Rostedt (Red Hat) return ERR_PTR(error); 4134282d606SSteven Rostedt (Red Hat) 4144282d606SSteven Rostedt (Red Hat) /* If the parent is not specified, we create it in the root. 4154282d606SSteven Rostedt (Red Hat) * We need the root dentry to do this, which is in the super 4164282d606SSteven Rostedt (Red Hat) * block. A pointer to that is in the struct vfsmount that we 4174282d606SSteven Rostedt (Red Hat) * have around. 4184282d606SSteven Rostedt (Red Hat) */ 4194282d606SSteven Rostedt (Red Hat) if (!parent) 4204282d606SSteven Rostedt (Red Hat) parent = tracefs_mount->mnt_root; 4214282d606SSteven Rostedt (Red Hat) 422ee34c52cSSteven Rostedt (VMware) inode_lock(d_inode(parent)); 423ee34c52cSSteven Rostedt (VMware) if (unlikely(IS_DEADDIR(d_inode(parent)))) 424a3d1e7ebSAl Viro dentry = ERR_PTR(-ENOENT); 425a3d1e7ebSAl Viro else 4264282d606SSteven Rostedt (Red Hat) dentry = lookup_one_len(name, parent, strlen(name)); 427ee34c52cSSteven Rostedt (VMware) if (!IS_ERR(dentry) && d_inode(dentry)) { 4284282d606SSteven Rostedt (Red Hat) dput(dentry); 4294282d606SSteven Rostedt (Red Hat) dentry = ERR_PTR(-EEXIST); 4304282d606SSteven Rostedt (Red Hat) } 431d227c3aeSDaniel Borkmann 432d227c3aeSDaniel Borkmann if (IS_ERR(dentry)) { 433ee34c52cSSteven Rostedt (VMware) inode_unlock(d_inode(parent)); 434d227c3aeSDaniel Borkmann simple_release_fs(&tracefs_mount, &tracefs_mount_count); 435d227c3aeSDaniel Borkmann } 436d227c3aeSDaniel Borkmann 4374282d606SSteven Rostedt (Red Hat) return dentry; 4384282d606SSteven Rostedt (Red Hat) } 4394282d606SSteven Rostedt (Red Hat) 4404282d606SSteven Rostedt (Red Hat) static struct dentry *failed_creating(struct dentry *dentry) 4414282d606SSteven Rostedt (Red Hat) { 442ee34c52cSSteven Rostedt (VMware) inode_unlock(d_inode(dentry->d_parent)); 4434282d606SSteven Rostedt (Red Hat) dput(dentry); 4444282d606SSteven Rostedt (Red Hat) simple_release_fs(&tracefs_mount, &tracefs_mount_count); 4454282d606SSteven Rostedt (Red Hat) return NULL; 4464282d606SSteven Rostedt (Red Hat) } 4474282d606SSteven Rostedt (Red Hat) 4484282d606SSteven Rostedt (Red Hat) static struct dentry *end_creating(struct dentry *dentry) 4494282d606SSteven Rostedt (Red Hat) { 450ee34c52cSSteven Rostedt (VMware) inode_unlock(d_inode(dentry->d_parent)); 4514282d606SSteven Rostedt (Red Hat) return dentry; 4524282d606SSteven Rostedt (Red Hat) } 4534282d606SSteven Rostedt (Red Hat) 4544282d606SSteven Rostedt (Red Hat) /** 4554282d606SSteven Rostedt (Red Hat) * tracefs_create_file - create a file in the tracefs filesystem 4564282d606SSteven Rostedt (Red Hat) * @name: a pointer to a string containing the name of the file to create. 4574282d606SSteven Rostedt (Red Hat) * @mode: the permission that the file should have. 4584282d606SSteven Rostedt (Red Hat) * @parent: a pointer to the parent dentry for this file. This should be a 4594282d606SSteven Rostedt (Red Hat) * directory dentry if set. If this parameter is NULL, then the 4604282d606SSteven Rostedt (Red Hat) * file will be created in the root of the tracefs filesystem. 4614282d606SSteven Rostedt (Red Hat) * @data: a pointer to something that the caller will want to get to later 4624282d606SSteven Rostedt (Red Hat) * on. The inode.i_private pointer will point to this value on 4634282d606SSteven Rostedt (Red Hat) * the open() call. 4644282d606SSteven Rostedt (Red Hat) * @fops: a pointer to a struct file_operations that should be used for 4654282d606SSteven Rostedt (Red Hat) * this file. 4664282d606SSteven Rostedt (Red Hat) * 4674282d606SSteven Rostedt (Red Hat) * This is the basic "create a file" function for tracefs. It allows for a 4684282d606SSteven Rostedt (Red Hat) * wide range of flexibility in creating a file, or a directory (if you want 4694282d606SSteven Rostedt (Red Hat) * to create a directory, the tracefs_create_dir() function is 4704282d606SSteven Rostedt (Red Hat) * recommended to be used instead.) 4714282d606SSteven Rostedt (Red Hat) * 4724282d606SSteven Rostedt (Red Hat) * This function will return a pointer to a dentry if it succeeds. This 4734282d606SSteven Rostedt (Red Hat) * pointer must be passed to the tracefs_remove() function when the file is 4744282d606SSteven Rostedt (Red Hat) * to be removed (no automatic cleanup happens if your module is unloaded, 4754282d606SSteven Rostedt (Red Hat) * you are responsible here.) If an error occurs, %NULL will be returned. 4764282d606SSteven Rostedt (Red Hat) * 4774282d606SSteven Rostedt (Red Hat) * If tracefs is not enabled in the kernel, the value -%ENODEV will be 4784282d606SSteven Rostedt (Red Hat) * returned. 4794282d606SSteven Rostedt (Red Hat) */ 4804282d606SSteven Rostedt (Red Hat) struct dentry *tracefs_create_file(const char *name, umode_t mode, 4814282d606SSteven Rostedt (Red Hat) struct dentry *parent, void *data, 4824282d606SSteven Rostedt (Red Hat) const struct file_operations *fops) 4834282d606SSteven Rostedt (Red Hat) { 4844282d606SSteven Rostedt (Red Hat) struct dentry *dentry; 4854282d606SSteven Rostedt (Red Hat) struct inode *inode; 4864282d606SSteven Rostedt (Red Hat) 487bf8e6021SSteven Rostedt (VMware) if (security_locked_down(LOCKDOWN_TRACEFS)) 488bf8e6021SSteven Rostedt (VMware) return NULL; 489bf8e6021SSteven Rostedt (VMware) 4904282d606SSteven Rostedt (Red Hat) if (!(mode & S_IFMT)) 4914282d606SSteven Rostedt (Red Hat) mode |= S_IFREG; 4924282d606SSteven Rostedt (Red Hat) BUG_ON(!S_ISREG(mode)); 4934282d606SSteven Rostedt (Red Hat) dentry = start_creating(name, parent); 4944282d606SSteven Rostedt (Red Hat) 4954282d606SSteven Rostedt (Red Hat) if (IS_ERR(dentry)) 4964282d606SSteven Rostedt (Red Hat) return NULL; 4974282d606SSteven Rostedt (Red Hat) 4984282d606SSteven Rostedt (Red Hat) inode = tracefs_get_inode(dentry->d_sb); 4994282d606SSteven Rostedt (Red Hat) if (unlikely(!inode)) 5004282d606SSteven Rostedt (Red Hat) return failed_creating(dentry); 5014282d606SSteven Rostedt (Red Hat) 5024282d606SSteven Rostedt (Red Hat) inode->i_mode = mode; 5033ed270b1SSteven Rostedt (VMware) inode->i_fop = fops ? fops : &tracefs_file_operations; 5044282d606SSteven Rostedt (Red Hat) inode->i_private = data; 505ee7f3666SSteven Rostedt (VMware) inode->i_uid = d_inode(dentry->d_parent)->i_uid; 506ee7f3666SSteven Rostedt (VMware) inode->i_gid = d_inode(dentry->d_parent)->i_gid; 5074282d606SSteven Rostedt (Red Hat) d_instantiate(dentry, inode); 508ee34c52cSSteven Rostedt (VMware) fsnotify_create(d_inode(dentry->d_parent), dentry); 5094282d606SSteven Rostedt (Red Hat) return end_creating(dentry); 5104282d606SSteven Rostedt (Red Hat) } 5114282d606SSteven Rostedt (Red Hat) 512eae47358SSteven Rostedt (Red Hat) static struct dentry *__create_dir(const char *name, struct dentry *parent, 513eae47358SSteven Rostedt (Red Hat) const struct inode_operations *ops) 514eae47358SSteven Rostedt (Red Hat) { 515eae47358SSteven Rostedt (Red Hat) struct dentry *dentry = start_creating(name, parent); 516eae47358SSteven Rostedt (Red Hat) struct inode *inode; 517eae47358SSteven Rostedt (Red Hat) 518eae47358SSteven Rostedt (Red Hat) if (IS_ERR(dentry)) 519eae47358SSteven Rostedt (Red Hat) return NULL; 520eae47358SSteven Rostedt (Red Hat) 521eae47358SSteven Rostedt (Red Hat) inode = tracefs_get_inode(dentry->d_sb); 522eae47358SSteven Rostedt (Red Hat) if (unlikely(!inode)) 523eae47358SSteven Rostedt (Red Hat) return failed_creating(dentry); 524eae47358SSteven Rostedt (Red Hat) 52549d67e44SSteven Rostedt (VMware) /* Do not set bits for OTH */ 52649d67e44SSteven Rostedt (VMware) inode->i_mode = S_IFDIR | S_IRWXU | S_IRUSR| S_IRGRP | S_IXUSR | S_IXGRP; 527eae47358SSteven Rostedt (Red Hat) inode->i_op = ops; 528eae47358SSteven Rostedt (Red Hat) inode->i_fop = &simple_dir_operations; 529ee7f3666SSteven Rostedt (VMware) inode->i_uid = d_inode(dentry->d_parent)->i_uid; 530ee7f3666SSteven Rostedt (VMware) inode->i_gid = d_inode(dentry->d_parent)->i_gid; 531eae47358SSteven Rostedt (Red Hat) 532eae47358SSteven Rostedt (Red Hat) /* directory inodes start off with i_nlink == 2 (for "." entry) */ 533eae47358SSteven Rostedt (Red Hat) inc_nlink(inode); 534eae47358SSteven Rostedt (Red Hat) d_instantiate(dentry, inode); 535ee34c52cSSteven Rostedt (VMware) inc_nlink(d_inode(dentry->d_parent)); 536ee34c52cSSteven Rostedt (VMware) fsnotify_mkdir(d_inode(dentry->d_parent), dentry); 537eae47358SSteven Rostedt (Red Hat) return end_creating(dentry); 538eae47358SSteven Rostedt (Red Hat) } 539eae47358SSteven Rostedt (Red Hat) 5404282d606SSteven Rostedt (Red Hat) /** 5414282d606SSteven Rostedt (Red Hat) * tracefs_create_dir - create a directory in the tracefs filesystem 5424282d606SSteven Rostedt (Red Hat) * @name: a pointer to a string containing the name of the directory to 5434282d606SSteven Rostedt (Red Hat) * create. 5444282d606SSteven Rostedt (Red Hat) * @parent: a pointer to the parent dentry for this file. This should be a 5454282d606SSteven Rostedt (Red Hat) * directory dentry if set. If this parameter is NULL, then the 5464282d606SSteven Rostedt (Red Hat) * directory will be created in the root of the tracefs filesystem. 5474282d606SSteven Rostedt (Red Hat) * 5484282d606SSteven Rostedt (Red Hat) * This function creates a directory in tracefs with the given name. 5494282d606SSteven Rostedt (Red Hat) * 5504282d606SSteven Rostedt (Red Hat) * This function will return a pointer to a dentry if it succeeds. This 5514282d606SSteven Rostedt (Red Hat) * pointer must be passed to the tracefs_remove() function when the file is 5524282d606SSteven Rostedt (Red Hat) * to be removed. If an error occurs, %NULL will be returned. 5534282d606SSteven Rostedt (Red Hat) * 5544282d606SSteven Rostedt (Red Hat) * If tracing is not enabled in the kernel, the value -%ENODEV will be 5554282d606SSteven Rostedt (Red Hat) * returned. 5564282d606SSteven Rostedt (Red Hat) */ 5574282d606SSteven Rostedt (Red Hat) struct dentry *tracefs_create_dir(const char *name, struct dentry *parent) 5584282d606SSteven Rostedt (Red Hat) { 559eae47358SSteven Rostedt (Red Hat) return __create_dir(name, parent, &simple_dir_inode_operations); 560eae47358SSteven Rostedt (Red Hat) } 5614282d606SSteven Rostedt (Red Hat) 562eae47358SSteven Rostedt (Red Hat) /** 563eae47358SSteven Rostedt (Red Hat) * tracefs_create_instance_dir - create the tracing instances directory 564eae47358SSteven Rostedt (Red Hat) * @name: The name of the instances directory to create 565eae47358SSteven Rostedt (Red Hat) * @parent: The parent directory that the instances directory will exist 566eae47358SSteven Rostedt (Red Hat) * @mkdir: The function to call when a mkdir is performed. 567eae47358SSteven Rostedt (Red Hat) * @rmdir: The function to call when a rmdir is performed. 568eae47358SSteven Rostedt (Red Hat) * 569eae47358SSteven Rostedt (Red Hat) * Only one instances directory is allowed. 570eae47358SSteven Rostedt (Red Hat) * 57193a8c044SXiang wangx * The instances directory is special as it allows for mkdir and rmdir 572eae47358SSteven Rostedt (Red Hat) * to be done by userspace. When a mkdir or rmdir is performed, the inode 573f2cc020dSIngo Molnar * locks are released and the methods passed in (@mkdir and @rmdir) are 574eae47358SSteven Rostedt (Red Hat) * called without locks and with the name of the directory being created 575eae47358SSteven Rostedt (Red Hat) * within the instances directory. 576eae47358SSteven Rostedt (Red Hat) * 577eae47358SSteven Rostedt (Red Hat) * Returns the dentry of the instances directory. 578eae47358SSteven Rostedt (Red Hat) */ 5795248ee85SZubin Mithra __init struct dentry *tracefs_create_instance_dir(const char *name, 5805248ee85SZubin Mithra struct dentry *parent, 581eae47358SSteven Rostedt (Red Hat) int (*mkdir)(const char *name), 582eae47358SSteven Rostedt (Red Hat) int (*rmdir)(const char *name)) 583eae47358SSteven Rostedt (Red Hat) { 584eae47358SSteven Rostedt (Red Hat) struct dentry *dentry; 585eae47358SSteven Rostedt (Red Hat) 586eae47358SSteven Rostedt (Red Hat) /* Only allow one instance of the instances directory. */ 587eae47358SSteven Rostedt (Red Hat) if (WARN_ON(tracefs_ops.mkdir || tracefs_ops.rmdir)) 5884282d606SSteven Rostedt (Red Hat) return NULL; 5894282d606SSteven Rostedt (Red Hat) 590eae47358SSteven Rostedt (Red Hat) dentry = __create_dir(name, parent, &tracefs_dir_inode_operations); 591eae47358SSteven Rostedt (Red Hat) if (!dentry) 592eae47358SSteven Rostedt (Red Hat) return NULL; 5934282d606SSteven Rostedt (Red Hat) 594eae47358SSteven Rostedt (Red Hat) tracefs_ops.mkdir = mkdir; 595eae47358SSteven Rostedt (Red Hat) tracefs_ops.rmdir = rmdir; 5964282d606SSteven Rostedt (Red Hat) 597eae47358SSteven Rostedt (Red Hat) return dentry; 5984282d606SSteven Rostedt (Red Hat) } 5994282d606SSteven Rostedt (Red Hat) 600a3d1e7ebSAl Viro static void remove_one(struct dentry *victim) 6014282d606SSteven Rostedt (Red Hat) { 6024282d606SSteven Rostedt (Red Hat) simple_release_fs(&tracefs_mount, &tracefs_mount_count); 6034282d606SSteven Rostedt (Red Hat) } 6044282d606SSteven Rostedt (Red Hat) 6054282d606SSteven Rostedt (Red Hat) /** 606a3d1e7ebSAl Viro * tracefs_remove - recursively removes a directory 6074282d606SSteven Rostedt (Red Hat) * @dentry: a pointer to a the dentry of the directory to be removed. 6084282d606SSteven Rostedt (Red Hat) * 6094282d606SSteven Rostedt (Red Hat) * This function recursively removes a directory tree in tracefs that 6104282d606SSteven Rostedt (Red Hat) * was previously created with a call to another tracefs function 6114282d606SSteven Rostedt (Red Hat) * (like tracefs_create_file() or variants thereof.) 6124282d606SSteven Rostedt (Red Hat) */ 613a3d1e7ebSAl Viro void tracefs_remove(struct dentry *dentry) 6144282d606SSteven Rostedt (Red Hat) { 6154282d606SSteven Rostedt (Red Hat) if (IS_ERR_OR_NULL(dentry)) 6164282d606SSteven Rostedt (Red Hat) return; 6174282d606SSteven Rostedt (Red Hat) 618a3d1e7ebSAl Viro simple_pin_fs(&trace_fs_type, &tracefs_mount, &tracefs_mount_count); 619a3d1e7ebSAl Viro simple_recursive_removal(dentry, remove_one); 6204282d606SSteven Rostedt (Red Hat) simple_release_fs(&tracefs_mount, &tracefs_mount_count); 6214282d606SSteven Rostedt (Red Hat) } 6224282d606SSteven Rostedt (Red Hat) 6234282d606SSteven Rostedt (Red Hat) /** 6244282d606SSteven Rostedt (Red Hat) * tracefs_initialized - Tells whether tracefs has been registered 6254282d606SSteven Rostedt (Red Hat) */ 6264282d606SSteven Rostedt (Red Hat) bool tracefs_initialized(void) 6274282d606SSteven Rostedt (Red Hat) { 6284282d606SSteven Rostedt (Red Hat) return tracefs_registered; 6294282d606SSteven Rostedt (Red Hat) } 6304282d606SSteven Rostedt (Red Hat) 6314282d606SSteven Rostedt (Red Hat) static int __init tracefs_init(void) 6324282d606SSteven Rostedt (Red Hat) { 6334282d606SSteven Rostedt (Red Hat) int retval; 6344282d606SSteven Rostedt (Red Hat) 635f9bb4882SEric W. Biederman retval = sysfs_create_mount_point(kernel_kobj, "tracing"); 636f9bb4882SEric W. Biederman if (retval) 637cc31004aSSteven Rostedt (Red Hat) return -EINVAL; 638cc31004aSSteven Rostedt (Red Hat) 6394282d606SSteven Rostedt (Red Hat) retval = register_filesystem(&trace_fs_type); 6404282d606SSteven Rostedt (Red Hat) if (!retval) 6414282d606SSteven Rostedt (Red Hat) tracefs_registered = true; 6424282d606SSteven Rostedt (Red Hat) 6434282d606SSteven Rostedt (Red Hat) return retval; 6444282d606SSteven Rostedt (Red Hat) } 6454282d606SSteven Rostedt (Red Hat) core_initcall(tracefs_init); 646