diff options
Diffstat (limited to 'fs/tracefs/event_inode.c')
-rw-r--r-- | fs/tracefs/event_inode.c | 178 |
1 files changed, 130 insertions, 48 deletions
diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c index f8a594a50ae6..f0677ea0ec24 100644 --- a/fs/tracefs/event_inode.c +++ b/fs/tracefs/event_inode.c @@ -27,16 +27,16 @@ /* * eventfs_mutex protects the eventfs_inode (ei) dentry. Any access * to the ei->dentry must be done under this mutex and after checking - * if ei->is_freed is not set. The ei->dentry is released under the - * mutex at the same time ei->is_freed is set. If ei->is_freed is set - * then the ei->dentry is invalid. + * if ei->is_freed is not set. When ei->is_freed is set, the dentry + * is on its way to being freed after the last dput() is made on it. */ static DEFINE_MUTEX(eventfs_mutex); /* * The eventfs_inode (ei) itself is protected by SRCU. It is released from * its parent's list and will have is_freed set (under eventfs_mutex). - * After the SRCU grace period is over, the ei may be freed. + * After the SRCU grace period is over and the last dput() is called + * the ei is freed. */ DEFINE_STATIC_SRCU(eventfs_srcu); @@ -95,7 +95,7 @@ static int eventfs_set_attr(struct mnt_idmap *idmap, struct dentry *dentry, if (!(dentry->d_inode->i_mode & S_IFDIR)) { if (!ei->entry_attrs) { ei->entry_attrs = kzalloc(sizeof(*ei->entry_attrs) * ei->nr_entries, - GFP_KERNEL); + GFP_NOFS); if (!ei->entry_attrs) { ret = -ENOMEM; goto out; @@ -113,7 +113,14 @@ static int eventfs_set_attr(struct mnt_idmap *idmap, struct dentry *dentry, * determined by the parent directory. */ if (dentry->d_inode->i_mode & S_IFDIR) { - update_attr(&ei->attr, iattr); + /* + * The events directory dentry is never freed, unless its + * part of an instance that is deleted. It's attr is the + * default for its child files and directories. + * Do not update it. It's not used for its own mode or ownership + */ + if (!ei->is_events) + update_attr(&ei->attr, iattr); } else { name = dentry->d_name.name; @@ -148,17 +155,49 @@ static const struct file_operations eventfs_file_operations = { .release = eventfs_release, }; -static void update_inode_attr(struct inode *inode, struct eventfs_attr *attr, umode_t mode) +/* Return the evenfs_inode of the "events" directory */ +static struct eventfs_inode *eventfs_find_events(struct dentry *dentry) +{ + struct eventfs_inode *ei; + + mutex_lock(&eventfs_mutex); + do { + /* The parent always has an ei, except for events itself */ + ei = dentry->d_parent->d_fsdata; + + /* + * If the ei is being freed, the ownership of the children + * doesn't matter. + */ + if (ei->is_freed) { + ei = NULL; + break; + } + + dentry = ei->dentry; + } while (!ei->is_events); + mutex_unlock(&eventfs_mutex); + + return ei; +} + +static void update_inode_attr(struct dentry *dentry, struct inode *inode, + struct eventfs_attr *attr, umode_t mode) { - if (!attr) { - inode->i_mode = mode; + struct eventfs_inode *events_ei = eventfs_find_events(dentry); + + if (!events_ei) + return; + + inode->i_mode = mode; + inode->i_uid = events_ei->attr.uid; + inode->i_gid = events_ei->attr.gid; + + if (!attr) return; - } if (attr->mode & EVENTFS_SAVE_MODE) inode->i_mode = attr->mode & EVENTFS_MODE_MASK; - else - inode->i_mode = mode; if (attr->mode & EVENTFS_SAVE_UID) inode->i_uid = attr->uid; @@ -167,6 +206,44 @@ static void update_inode_attr(struct inode *inode, struct eventfs_attr *attr, um inode->i_gid = attr->gid; } +static void update_gid(struct eventfs_inode *ei, kgid_t gid, int level) +{ + struct eventfs_inode *ei_child; + + /* at most we have events/system/event */ + if (WARN_ON_ONCE(level > 3)) + return; + + ei->attr.gid = gid; + + if (ei->entry_attrs) { + for (int i = 0; i < ei->nr_entries; i++) { + ei->entry_attrs[i].gid = gid; + } + } + + /* + * Only eventfs_inode with dentries are updated, make sure + * all eventfs_inodes are updated. If one of the children + * do not have a dentry, this function must traverse it. + */ + list_for_each_entry_srcu(ei_child, &ei->children, list, + srcu_read_lock_held(&eventfs_srcu)) { + if (!ei_child->dentry) + update_gid(ei_child, gid, level + 1); + } +} + +void eventfs_update_gid(struct dentry *dentry, kgid_t gid) +{ + struct eventfs_inode *ei = dentry->d_fsdata; + int idx; + + idx = srcu_read_lock(&eventfs_srcu); + update_gid(ei, gid, 0); + srcu_read_unlock(&eventfs_srcu, idx); +} + /** * create_file - create a file in the tracefs filesystem * @name: the name of the file to create. @@ -206,7 +283,7 @@ static struct dentry *create_file(const char *name, umode_t mode, return eventfs_failed_creating(dentry); /* If the user updated the directory's attributes, use them */ - update_inode_attr(inode, attr, mode); + update_inode_attr(dentry, inode, attr, mode); inode->i_op = &eventfs_file_inode_operations; inode->i_fop = fop; @@ -242,7 +319,8 @@ static struct dentry *create_dir(struct eventfs_inode *ei, struct dentry *parent return eventfs_failed_creating(dentry); /* If the user updated the directory's attributes, use them */ - update_inode_attr(inode, &ei->attr, S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO); + update_inode_attr(dentry, inode, &ei->attr, + S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO); inode->i_op = &eventfs_root_dir_inode_operations; inode->i_fop = &eventfs_file_operations; @@ -326,7 +404,8 @@ create_file_dentry(struct eventfs_inode *ei, int idx, struct eventfs_attr *attr = NULL; struct dentry **e_dentry = &ei->d_children[idx]; struct dentry *dentry; - bool invalidate = false; + + WARN_ON_ONCE(!inode_is_locked(parent->d_inode)); mutex_lock(&eventfs_mutex); if (ei->is_freed) { @@ -348,15 +427,8 @@ create_file_dentry(struct eventfs_inode *ei, int idx, mutex_unlock(&eventfs_mutex); - /* The lookup already has the parent->d_inode locked */ - if (!lookup) - inode_lock(parent->d_inode); - dentry = create_file(name, mode, attr, parent, data, fops); - if (!lookup) - inode_unlock(parent->d_inode); - mutex_lock(&eventfs_mutex); if (IS_ERR_OR_NULL(dentry)) { @@ -365,12 +437,14 @@ create_file_dentry(struct eventfs_inode *ei, int idx, * created the dentry for this e_dentry. In which case * use that one. * - * Note, with the mutex held, the e_dentry cannot have content - * and the ei->is_freed be true at the same time. + * If ei->is_freed is set, the e_dentry is currently on its + * way to being freed, don't return it. If e_dentry is NULL + * it means it was already freed. */ - dentry = *e_dentry; - if (WARN_ON_ONCE(dentry && ei->is_freed)) + if (ei->is_freed) dentry = NULL; + else + dentry = *e_dentry; /* The lookup does not need to up the dentry refcount */ if (dentry && !lookup) dget(dentry); @@ -387,17 +461,14 @@ create_file_dentry(struct eventfs_inode *ei, int idx, * Otherwise it means two dentries exist with the same name. */ WARN_ON_ONCE(!ei->is_freed); - invalidate = true; + dentry = NULL; } mutex_unlock(&eventfs_mutex); - if (invalidate) - d_invalidate(dentry); - - if (lookup || invalidate) + if (lookup) dput(dentry); - return invalidate ? NULL : dentry; + return dentry; } /** @@ -437,9 +508,10 @@ static struct dentry * create_dir_dentry(struct eventfs_inode *pei, struct eventfs_inode *ei, struct dentry *parent, bool lookup) { - bool invalidate = false; struct dentry *dentry = NULL; + WARN_ON_ONCE(!inode_is_locked(parent->d_inode)); + mutex_lock(&eventfs_mutex); if (pei->is_freed || ei->is_freed) { mutex_unlock(&eventfs_mutex); @@ -456,15 +528,8 @@ create_dir_dentry(struct eventfs_inode *pei, struct eventfs_inode *ei, } mutex_unlock(&eventfs_mutex); - /* The lookup already has the parent->d_inode locked */ - if (!lookup) - inode_lock(parent->d_inode); - dentry = create_dir(ei, parent); - if (!lookup) - inode_unlock(parent->d_inode); - mutex_lock(&eventfs_mutex); if (IS_ERR_OR_NULL(dentry) && !ei->is_freed) { @@ -473,8 +538,8 @@ create_dir_dentry(struct eventfs_inode *pei, struct eventfs_inode *ei, * created the dentry for this e_dentry. In which case * use that one. * - * Note, with the mutex held, the e_dentry cannot have content - * and the ei->is_freed be true at the same time. + * If ei->is_freed is set, the e_dentry is currently on its + * way to being freed. */ dentry = ei->dentry; if (dentry && !lookup) @@ -493,16 +558,14 @@ create_dir_dentry(struct eventfs_inode *pei, struct eventfs_inode *ei, * Otherwise it means two dentries exist with the same name. */ WARN_ON_ONCE(!ei->is_freed); - invalidate = true; + dentry = NULL; } mutex_unlock(&eventfs_mutex); - if (invalidate) - d_invalidate(dentry); - if (lookup || invalidate) + if (lookup) dput(dentry); - return invalidate ? NULL : dentry; + return dentry; } /** @@ -561,6 +624,8 @@ static struct dentry *eventfs_root_lookup(struct inode *dir, if (strcmp(ei_child->name, name) != 0) continue; ret = simple_lookup(dir, dentry, flags); + if (IS_ERR(ret)) + goto out; create_dir_dentry(ei, ei_child, ei_dentry, true); created = true; break; @@ -583,6 +648,8 @@ static struct dentry *eventfs_root_lookup(struct inode *dir, if (r <= 0) continue; ret = simple_lookup(dir, dentry, flags); + if (IS_ERR(ret)) + goto out; create_file_dentry(ei, i, ei_dentry, name, mode, cdata, fops, true); break; @@ -632,7 +699,7 @@ static int add_dentries(struct dentry ***dentries, struct dentry *d, int cnt) { struct dentry **tmp; - tmp = krealloc(*dentries, sizeof(d) * (cnt + 2), GFP_KERNEL); + tmp = krealloc(*dentries, sizeof(d) * (cnt + 2), GFP_NOFS); if (!tmp) return -1; tmp[cnt] = d; @@ -698,6 +765,7 @@ static int dcache_dir_open_wrapper(struct inode *inode, struct file *file) return -ENOMEM; } + inode_lock(parent->d_inode); list_for_each_entry_srcu(ei_child, &ei->children, list, srcu_read_lock_held(&eventfs_srcu)) { d = create_dir_dentry(ei, ei_child, parent, false); @@ -730,6 +798,7 @@ static int dcache_dir_open_wrapper(struct inode *inode, struct file *file) cnt++; } } + inode_unlock(parent->d_inode); srcu_read_unlock(&eventfs_srcu, idx); ret = dcache_dir_open(inode, file); @@ -863,6 +932,8 @@ struct eventfs_inode *eventfs_create_events_dir(const char *name, struct dentry struct eventfs_inode *ei; struct tracefs_inode *ti; struct inode *inode; + kuid_t uid; + kgid_t gid; if (security_locked_down(LOCKDOWN_TRACEFS)) return NULL; @@ -887,11 +958,20 @@ struct eventfs_inode *eventfs_create_events_dir(const char *name, struct dentry ei->dentry = dentry; ei->entries = entries; ei->nr_entries = size; + ei->is_events = 1; ei->data = data; ei->name = kstrdup_const(name, GFP_KERNEL); if (!ei->name) goto fail; + /* Save the ownership of this directory */ + uid = d_inode(dentry->d_parent)->i_uid; + gid = d_inode(dentry->d_parent)->i_gid; + + /* This is used as the default ownership of the files and directories */ + ei->attr.uid = uid; + ei->attr.gid = gid; + INIT_LIST_HEAD(&ei->children); INIT_LIST_HEAD(&ei->list); @@ -900,6 +980,8 @@ struct eventfs_inode *eventfs_create_events_dir(const char *name, struct dentry ti->private = ei; inode->i_mode = S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO; + inode->i_uid = uid; + inode->i_gid = gid; inode->i_op = &eventfs_root_dir_inode_operations; inode->i_fop = &eventfs_file_operations; |