fs/configfs/configfs_internal.h

File Facts

System

Linux kernel

Corpus path

fs/configfs/configfs_internal.h

Extension

.h

Size

4714 bytes

Lines

159

Domain

Core OS

Bucket

VFS And Filesystem Core

Inferred role

Core OS: operation-table or driver-model contract

Status

pattern implementation candidate

Why This File Exists

Core operating-system implementation surface: boot, tasks, memory, VFS, syscall-facing interfaces, synchronization, credentials, and isolation.

• Core operating-system implementation surface: boot, tasks, memory, VFS, syscall-facing interfaces, synchronization, credentials, and isolation.
• Defines an operation table; this is where Linux turns generic core objects into subsystem-specific behavior.
• Uses kernel synchronization; read lock ordering, sleepability, and interrupt context assumptions before translating.
• Defines or uses C structs; map object ownership, embedded links, reference counts, and lock ownership.

Dependency Surface

• linux/slab.h
• linux/list.h
• linux/spinlock.h

Detected Declarations

• struct configfs_fragment
• struct configfs_dirent
• function to_item
• function to_attr
• function release_configfs_dirent
• function configfs_get
• function configfs_put

Annotated Snippet

extern const struct file_operations configfs_dir_operations;
extern const struct file_operations configfs_file_operations;
extern const struct file_operations configfs_bin_file_operations;
extern const struct inode_operations configfs_dir_inode_operations;
extern const struct inode_operations configfs_root_inode_operations;
extern const struct inode_operations configfs_symlink_inode_operations;
extern const struct dentry_operations configfs_dentry_ops;

extern int configfs_symlink(struct mnt_idmap *idmap,
			    struct inode *dir, struct dentry *dentry,
			    const char *symname);
extern int configfs_unlink(struct inode *dir, struct dentry *dentry);

int configfs_create_link(struct configfs_dirent *target, struct dentry *parent,
		struct dentry *dentry, char *body);

static inline struct config_item * to_item(struct dentry * dentry)
{
	struct configfs_dirent * sd = dentry->d_fsdata;
	return ((struct config_item *) sd->s_element);
}

static inline struct configfs_attribute * to_attr(struct dentry * dentry)
{
	struct configfs_dirent * sd = dentry->d_fsdata;
	return ((struct configfs_attribute *) sd->s_element);
}

static inline struct configfs_bin_attribute *to_bin_attr(struct dentry *dentry)
{
	struct configfs_attribute *attr = to_attr(dentry);

	return container_of(attr, struct configfs_bin_attribute, cb_attr);
}

static inline struct config_item *configfs_get_config_item(struct dentry *dentry)
{
	struct config_item * item = NULL;

	spin_lock(&dentry->d_lock);
	if (!d_unhashed(dentry)) {
		struct configfs_dirent * sd = dentry->d_fsdata;
		item = config_item_get(sd->s_element);
	}
	spin_unlock(&dentry->d_lock);

	return item;
}

static inline void release_configfs_dirent(struct configfs_dirent * sd)
{
	if (!(sd->s_type & CONFIGFS_ROOT)) {
		kfree(sd->s_iattr);
		put_fragment(sd->s_frag);
		kmem_cache_free(configfs_dir_cachep, sd);
	}
}

static inline struct configfs_dirent * configfs_get(struct configfs_dirent * sd)
{
	if (sd) {
		WARN_ON(!atomic_read(&sd->s_count));
		atomic_inc(&sd->s_count);
	}
	return sd;
}

static inline void configfs_put(struct configfs_dirent * sd)
{
	WARN_ON(!atomic_read(&sd->s_count));
	if (atomic_dec_and_test(&sd->s_count))
		release_configfs_dirent(sd);
}

Annotation

• Immediate include surface: `linux/slab.h`, `linux/list.h`, `linux/spinlock.h`.
• Detected declarations: `struct configfs_fragment`, `struct configfs_dirent`, `function to_item`, `function to_attr`, `function release_configfs_dirent`, `function configfs_get`, `function configfs_put`.
• Atlas domain: Core OS / VFS And Filesystem Core.
• Implementation status: pattern implementation candidate.
• Synchronization appears in or near this file; preserve lock ordering, sleepability, and interrupt-context constraints.

Implementation Notes

• This generated page is the file-by-file coverage layer; curated subsystem chapters should link here when they synthesize a multi-file control flow.
• Core OS pages should be promoted from atlas-only to deep-reviewed when they explain data structures, invariants, locking, lifecycle, and C implementation snippets.
• Driver-family pages are intentionally pattern-oriented unless they are part of the selected PCIe/NVMe representative device path.