fs/coda/pioctl.c

File Facts

System

Linux kernel

Corpus path

fs/coda/pioctl.c

Extension

.c

Size

2249 bytes

Lines

89

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.
• Touches user memory; correctness depends on fault-safe copying and privilege boundary handling.
• Defines or uses C structs; map object ownership, embedded links, reference counts, and lock ownership.

Dependency Surface

• linux/types.h
• linux/kernel.h
• linux/time.h
• linux/fs.h
• linux/stat.h
• linux/errno.h
• linux/string.h
• linux/namei.h
• linux/module.h
• linux/uaccess.h
• linux/coda.h
• coda_psdev.h
• coda_linux.h

Detected Declarations

• function coda_ioctl_permission
• function coda_pioctl

Annotated Snippet

const struct file_operations coda_ioctl_operations = {
	.unlocked_ioctl	= coda_pioctl,
	.llseek		= noop_llseek,
};

/* the coda pioctl inode ops */
static int coda_ioctl_permission(struct mnt_idmap *idmap,
				 struct inode *inode, int mask)
{
	return (mask & MAY_EXEC) ? -EACCES : 0;
}

static long coda_pioctl(struct file *filp, unsigned int cmd,
			unsigned long user_data)
{
	struct path path;
	int error;
	struct PioctlData data;
	struct inode *inode = file_inode(filp);
	struct inode *target_inode = NULL;
	struct coda_inode_info *cnp;

	/* get the Pioctl data arguments from user space */
	if (copy_from_user(&data, (void __user *)user_data, sizeof(data)))
		return -EINVAL;

	/*
	 * Look up the pathname. Note that the pathname is in
	 * user memory, and namei takes care of this
	 */
	error = user_path_at(AT_FDCWD, data.path,
			     data.follow ? LOOKUP_FOLLOW : 0, &path);
	if (error)
		return error;

	target_inode = d_inode(path.dentry);

	/* return if it is not a Coda inode */
	if (target_inode->i_sb != inode->i_sb) {
		error = -EINVAL;
		goto out;
	}

	/* now proceed to make the upcall */
	cnp = ITOC(target_inode);

	error = venus_pioctl(inode->i_sb, &(cnp->c_fid), cmd, &data);
out:
	path_put(&path);
	return error;
}

Annotation

• Immediate include surface: `linux/types.h`, `linux/kernel.h`, `linux/time.h`, `linux/fs.h`, `linux/stat.h`, `linux/errno.h`, `linux/string.h`, `linux/namei.h`.
• Detected declarations: `function coda_ioctl_permission`, `function coda_pioctl`.
• Atlas domain: Core OS / VFS And Filesystem Core.
• Implementation status: pattern implementation candidate.
• This snippet crosses the user/kernel memory boundary; validate fault handling and access checks before translating the pattern.

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.