diff options
Diffstat (limited to 'fs/kernfs/kernfs-internal.h')
| -rw-r--r-- | fs/kernfs/kernfs-internal.h | 126 |
1 files changed, 108 insertions, 18 deletions
diff --git a/fs/kernfs/kernfs-internal.h b/fs/kernfs/kernfs-internal.h index 3d83b114bb08..6061b6f70d2a 100644 --- a/fs/kernfs/kernfs-internal.h +++ b/fs/kernfs/kernfs-internal.h @@ -1,11 +1,10 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ /* * fs/kernfs/kernfs-internal.h - kernfs internal header file * * Copyright (c) 2001-3 Patrick Mochel * Copyright (c) 2007 SUSE Linux Products GmbH * Copyright (c) 2007, 2013 Tejun Heo <teheo@suse.de> - * - * This file is released under the GPLv2. */ #ifndef __KERNFS_INTERNAL_H @@ -14,16 +13,48 @@ #include <linux/lockdep.h> #include <linux/fs.h> #include <linux/mutex.h> +#include <linux/rwsem.h> #include <linux/xattr.h> #include <linux/kernfs.h> +#include <linux/fs_context.h> struct kernfs_iattrs { - struct iattr ia_iattr; - void *ia_secdata; - u32 ia_secdata_len; + kuid_t ia_uid; + kgid_t ia_gid; + struct timespec64 ia_atime; + struct timespec64 ia_mtime; + struct timespec64 ia_ctime; struct simple_xattrs xattrs; + atomic_t nr_user_xattrs; + atomic_t user_xattr_size; +}; + +struct kernfs_root { + /* published fields */ + struct kernfs_node *kn; + unsigned int flags; /* KERNFS_ROOT_* flags */ + + /* private fields, do not use outside kernfs proper */ + struct idr ino_idr; + spinlock_t kernfs_idr_lock; /* root->ino_idr */ + u32 last_id_lowbits; + u32 id_highbits; + struct kernfs_syscall_ops *syscall_ops; + + /* list of kernfs_super_info of this root, protected by kernfs_rwsem */ + struct list_head supers; + + wait_queue_head_t deactivate_waitq; + struct rw_semaphore kernfs_rwsem; + struct rw_semaphore kernfs_iattr_rwsem; + struct rw_semaphore kernfs_supers_rwsem; + + /* kn->parent and kn->name */ + rwlock_t kernfs_rename_lock; + + struct rcu_head rcu; }; /* +1 to avoid triggering overflow warning when negating it */ @@ -35,13 +66,16 @@ struct kernfs_iattrs { * kernfs_root - find out the kernfs_root a kernfs_node belongs to * @kn: kernfs_node of interest * - * Return the kernfs_root @kn belongs to. + * Return: the kernfs_root @kn belongs to. */ -static inline struct kernfs_root *kernfs_root(struct kernfs_node *kn) +static inline struct kernfs_root *kernfs_root(const struct kernfs_node *kn) { + const struct kernfs_node *knp; /* if parent exists, it's always a dir; otherwise, @sd is a dir */ - if (kn->parent) - kn = kn->parent; + guard(rcu)(); + knp = rcu_dereference(kn->__parent); + if (knp) + kn = knp; return kn->dir.root; } @@ -65,11 +99,43 @@ struct kernfs_super_info { */ const void *ns; - /* anchored at kernfs_root->supers, protected by kernfs_mutex */ + /* anchored at kernfs_root->supers, protected by kernfs_rwsem */ struct list_head node; }; #define kernfs_info(SB) ((struct kernfs_super_info *)(SB->s_fs_info)) +static inline bool kernfs_root_is_locked(const struct kernfs_node *kn) +{ + return lockdep_is_held(&kernfs_root(kn)->kernfs_rwsem); +} + +static inline bool kernfs_rename_is_locked(const struct kernfs_node *kn) +{ + return lockdep_is_held(&kernfs_root(kn)->kernfs_rename_lock); +} + +static inline const char *kernfs_rcu_name(const struct kernfs_node *kn) +{ + return rcu_dereference_check(kn->name, kernfs_root_is_locked(kn)); +} + +static inline struct kernfs_node *kernfs_parent(const struct kernfs_node *kn) +{ + /* + * The kernfs_node::__parent remains valid within a RCU section. The kn + * can be reparented (and renamed) which changes the entry. This can be + * avoided by locking kernfs_root::kernfs_rwsem or + * kernfs_root::kernfs_rename_lock. + * Both locks can be used to obtain a reference on __parent. Once the + * reference count reaches 0 then the node is about to be freed + * and can not be renamed (or become a different parent) anymore. + */ + return rcu_dereference_check(kn->__parent, + kernfs_root_is_locked(kn) || + kernfs_rename_is_locked(kn) || + !atomic_read(&kn->count)); +} + static inline struct kernfs_node *kernfs_dentry_node(struct dentry *dentry) { if (d_really_is_negative(dentry)) @@ -77,17 +143,39 @@ static inline struct kernfs_node *kernfs_dentry_node(struct dentry *dentry) return d_inode(dentry)->i_private; } +static inline void kernfs_set_rev(struct kernfs_node *parent, + struct dentry *dentry) +{ + dentry->d_time = parent->dir.rev; +} + +static inline void kernfs_inc_rev(struct kernfs_node *parent) +{ + parent->dir.rev++; +} + +static inline bool kernfs_dir_changed(struct kernfs_node *parent, + struct dentry *dentry) +{ + if (parent->dir.rev != dentry->d_time) + return true; + return false; +} + extern const struct super_operations kernfs_sops; -extern struct kmem_cache *kernfs_node_cache; +extern struct kmem_cache *kernfs_node_cache, *kernfs_iattrs_cache; /* * inode.c */ -extern const struct xattr_handler *kernfs_xattr_handlers[]; +extern const struct xattr_handler * const kernfs_xattr_handlers[]; void kernfs_evict_inode(struct inode *inode); -int kernfs_iop_permission(struct inode *inode, int mask); -int kernfs_iop_setattr(struct dentry *dentry, struct iattr *iattr); -int kernfs_iop_getattr(const struct path *path, struct kstat *stat, +int kernfs_iop_permission(struct mnt_idmap *idmap, + struct inode *inode, int mask); +int kernfs_iop_setattr(struct mnt_idmap *idmap, struct dentry *dentry, + struct iattr *iattr); +int kernfs_iop_getattr(struct mnt_idmap *idmap, + const struct path *path, struct kstat *stat, u32 request_mask, unsigned int query_flags); ssize_t kernfs_iop_listxattr(struct dentry *dentry, char *buf, size_t size); int __kernfs_setattr(struct kernfs_node *kn, const struct iattr *iattr); @@ -95,7 +183,6 @@ int __kernfs_setattr(struct kernfs_node *kn, const struct iattr *iattr); /* * dir.c */ -extern struct mutex kernfs_mutex; extern const struct dentry_operations kernfs_dops; extern const struct file_operations kernfs_dir_fops; extern const struct inode_operations kernfs_dir_iops; @@ -107,14 +194,13 @@ struct kernfs_node *kernfs_new_node(struct kernfs_node *parent, const char *name, umode_t mode, kuid_t uid, kgid_t gid, unsigned flags); -struct kernfs_node *kernfs_find_and_get_node_by_ino(struct kernfs_root *root, - unsigned int ino); /* * file.c */ extern const struct file_operations kernfs_file_fops; +bool kernfs_should_drain_open_files(struct kernfs_node *kn); void kernfs_drain_open_files(struct kernfs_node *kn); /* @@ -122,4 +208,8 @@ void kernfs_drain_open_files(struct kernfs_node *kn); */ extern const struct inode_operations kernfs_symlink_iops; +/* + * kernfs locks + */ +extern struct kernfs_global_locks *kernfs_locks; #endif /* __KERNFS_INTERNAL_H */ |