diff options
| -rw-r--r-- | fs/kernfs/dir.c | 71 | ||||
| -rw-r--r-- | fs/kernfs/kernfs-internal.h | 20 | ||||
| -rw-r--r-- | fs/sysfs/mount.c | 29 | ||||
| -rw-r--r-- | include/linux/kernfs.h | 13 |
4 files changed, 113 insertions, 20 deletions
diff --git a/fs/kernfs/dir.c b/fs/kernfs/dir.c index a4ca4de3cb21..246740a741ef 100644 --- a/fs/kernfs/dir.c +++ b/fs/kernfs/dir.c @@ -211,7 +211,7 @@ static int sysfs_alloc_ino(unsigned int *pino) retry: spin_lock(&sysfs_ino_lock); - rc = ida_get_new_above(&sysfs_ino_ida, 2, &ino); + rc = ida_get_new_above(&sysfs_ino_ida, 1, &ino); spin_unlock(&sysfs_ino_lock); if (rc == -EAGAIN) { @@ -253,9 +253,11 @@ EXPORT_SYMBOL_GPL(kernfs_get); void kernfs_put(struct sysfs_dirent *sd) { struct sysfs_dirent *parent_sd; + struct kernfs_root *root; if (!sd || !atomic_dec_and_test(&sd->s_count)) return; + root = kernfs_root(sd); repeat: /* Moving/renaming is always done while holding reference. * sd->s_parent won't change beneath us. @@ -278,8 +280,13 @@ void kernfs_put(struct sysfs_dirent *sd) kmem_cache_free(sysfs_dir_cachep, sd); sd = parent_sd; - if (sd && atomic_dec_and_test(&sd->s_count)) - goto repeat; + if (sd) { + if (atomic_dec_and_test(&sd->s_count)) + goto repeat; + } else { + /* just released the root sd, free @root too */ + kfree(root); + } } EXPORT_SYMBOL_GPL(kernfs_put); @@ -493,13 +500,15 @@ static void sysfs_remove_one(struct sysfs_addrm_cxt *acxt, if (sd->s_flags & SYSFS_FLAG_REMOVED) return; - sysfs_unlink_sibling(sd); + if (sd->s_parent) { + sysfs_unlink_sibling(sd); - /* Update timestamps on the parent */ - ps_iattr = sd->s_parent->s_iattr; - if (ps_iattr) { - struct iattr *ps_iattrs = &ps_iattr->ia_iattr; - ps_iattrs->ia_ctime = ps_iattrs->ia_mtime = CURRENT_TIME; + /* Update timestamps on the parent */ + ps_iattr = sd->s_parent->s_iattr; + if (ps_iattr) { + ps_iattr->ia_iattr.ia_ctime = CURRENT_TIME; + ps_iattr->ia_iattr.ia_mtime = CURRENT_TIME; + } } sd->s_flags |= SYSFS_FLAG_REMOVED; @@ -604,6 +613,49 @@ struct sysfs_dirent *kernfs_find_and_get_ns(struct sysfs_dirent *parent, EXPORT_SYMBOL_GPL(kernfs_find_and_get_ns); /** + * kernfs_create_root - create a new kernfs hierarchy + * @priv: opaque data associated with the new directory + * + * Returns the root of the new hierarchy on success, ERR_PTR() value on + * failure. + */ +struct kernfs_root *kernfs_create_root(void *priv) +{ + struct kernfs_root *root; + struct sysfs_dirent *sd; + + root = kzalloc(sizeof(*root), GFP_KERNEL); + if (!root) + return ERR_PTR(-ENOMEM); + + sd = sysfs_new_dirent("", S_IFDIR | S_IRUGO | S_IXUGO, SYSFS_DIR); + if (!sd) { + kfree(root); + return ERR_PTR(-ENOMEM); + } + + sd->s_flags &= ~SYSFS_FLAG_REMOVED; + sd->priv = priv; + sd->s_dir.root = root; + + root->sd = sd; + + return root; +} + +/** + * kernfs_destroy_root - destroy a kernfs hierarchy + * @root: root of the hierarchy to destroy + * + * Destroy the hierarchy anchored at @root by removing all existing + * directories and destroying @root. + */ +void kernfs_destroy_root(struct kernfs_root *root) +{ + kernfs_remove(root->sd); /* will also free @root */ +} + +/** * kernfs_create_dir_ns - create a directory * @parent: parent in which to create a new directory * @name: name of the new directory @@ -626,6 +678,7 @@ struct sysfs_dirent *kernfs_create_dir_ns(struct sysfs_dirent *parent, if (!sd) return ERR_PTR(-ENOMEM); + sd->s_dir.root = parent->s_dir.root; sd->s_ns = ns; sd->priv = priv; diff --git a/fs/kernfs/kernfs-internal.h b/fs/kernfs/kernfs-internal.h index 62ae35f997f7..7dfe06278350 100644 --- a/fs/kernfs/kernfs-internal.h +++ b/fs/kernfs/kernfs-internal.h @@ -25,6 +25,12 @@ struct sysfs_elem_dir { unsigned long subdirs; /* children rbtree starts here and goes through sd->s_rb */ struct rb_root children; + + /* + * The kernfs hierarchy this directory belongs to. This fits + * better directly in sysfs_dirent but is here to save space. + */ + struct kernfs_root *root; }; struct sysfs_elem_symlink { @@ -104,6 +110,20 @@ static inline unsigned int sysfs_type(struct sysfs_dirent *sd) return sd->s_flags & SYSFS_TYPE_MASK; } +/** + * kernfs_root - find out the kernfs_root a sysfs_dirent belongs to + * @sd: sysfs_dirent of interest + * + * Return the kernfs_root @sd belongs to. + */ +static inline struct kernfs_root *kernfs_root(struct sysfs_dirent *sd) +{ + /* if parent exists, it's always a dir; otherwise, @sd is a dir */ + if (sd->s_parent) + sd = sd->s_parent; + return sd->s_dir.root; +} + /* * Context structure to be used while adding/removing nodes. */ diff --git a/fs/sysfs/mount.c b/fs/sysfs/mount.c index 7cbd1fce2826..0b5661b462f7 100644 --- a/fs/sysfs/mount.c +++ b/fs/sysfs/mount.c @@ -32,15 +32,8 @@ static const struct super_operations sysfs_ops = { .evict_inode = sysfs_evict_inode, }; -static struct sysfs_dirent sysfs_root = { - .s_name = "", - .s_count = ATOMIC_INIT(1), - .s_flags = SYSFS_DIR, - .s_mode = S_IFDIR | S_IRUGO | S_IXUGO, - .s_ino = 1, -}; - -struct sysfs_dirent *sysfs_root_sd = &sysfs_root; +static struct kernfs_root *sysfs_root; +struct sysfs_dirent *sysfs_root_sd; static int sysfs_fill_super(struct super_block *sb) { @@ -68,6 +61,7 @@ static int sysfs_fill_super(struct super_block *sb) pr_debug("%s: could not get root dentry!\n", __func__); return -ENOMEM; } + kernfs_get(sysfs_root_sd); root->d_fsdata = sysfs_root_sd; sb->s_root = root; sb->s_d_op = &sysfs_dentry_ops; @@ -138,11 +132,15 @@ static struct dentry *sysfs_mount(struct file_system_type *fs_type, static void sysfs_kill_sb(struct super_block *sb) { struct sysfs_super_info *info = sysfs_info(sb); - /* Remove the superblock from fs_supers/s_instances + struct sysfs_dirent *root_sd = sb->s_root->d_fsdata; + + /* + * Remove the superblock from fs_supers/s_instances * so we can't find it, before freeing sysfs_super_info. */ kill_anon_super(sb); free_sysfs_super_info(info); + kernfs_put(root_sd); } static struct file_system_type sysfs_fs_type = { @@ -166,12 +164,21 @@ int __init sysfs_init(void) if (err) goto out_err; + sysfs_root = kernfs_create_root(NULL); + if (IS_ERR(sysfs_root)) { + err = PTR_ERR(sysfs_root); + goto out_err; + } + sysfs_root_sd = sysfs_root->sd; + err = register_filesystem(&sysfs_fs_type); if (err) - goto out_err; + goto out_destroy_root; return 0; +out_destroy_root: + kernfs_destroy_root(sysfs_root); out_err: kmem_cache_destroy(sysfs_dir_cachep); sysfs_dir_cachep = NULL; diff --git a/include/linux/kernfs.h b/include/linux/kernfs.h index fd8f574ef2fe..f75548b8ed7a 100644 --- a/include/linux/kernfs.h +++ b/include/linux/kernfs.h @@ -20,6 +20,11 @@ struct vm_area_struct; struct sysfs_dirent; +struct kernfs_root { + /* published fields */ + struct sysfs_dirent *sd; +}; + struct sysfs_open_file { /* published fields */ struct sysfs_dirent *sd; @@ -76,6 +81,9 @@ struct sysfs_dirent *kernfs_find_and_get_ns(struct sysfs_dirent *parent, void kernfs_get(struct sysfs_dirent *sd); void kernfs_put(struct sysfs_dirent *sd); +struct kernfs_root *kernfs_create_root(void *priv); +void kernfs_destroy_root(struct kernfs_root *root); + struct sysfs_dirent *kernfs_create_dir_ns(struct sysfs_dirent *parent, const char *name, void *priv, const void *ns); @@ -107,6 +115,11 @@ kernfs_find_and_get_ns(struct sysfs_dirent *parent, const char *name, static inline void kernfs_get(struct sysfs_dirent *sd) { } static inline void kernfs_put(struct sysfs_dirent *sd) { } +static inline struct kernfs_root *kernfs_create_root(void *priv) +{ return ERR_PTR(-ENOSYS); } + +static inline void kernfs_destroy_root(struct kernfs_root *root) { } + static inline struct sysfs_dirent * kernfs_create_dir_ns(struct sysfs_dirent *parent, const char *name, void *priv, const void *ns) |