fs/overlayfs/file.c

File Facts

System

Linux kernel

Corpus path

fs/overlayfs/file.c

Extension

.c

Size

15175 bytes

Lines

653

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.
• Allocates kernel memory; connect allocation flags and lifetime to context constraints.
• Defines or uses C structs; map object ownership, embedded links, reference counts, and lock ownership.

Dependency Surface

• linux/cred.h
• linux/file.h
• linux/filelock.h
• linux/mount.h
• linux/xattr.h
• linux/uio.h
• linux/uaccess.h
• linux/security.h
• linux/fs.h
• linux/backing-file.h
• overlayfs.h

Detected Declarations

• struct ovl_file
• enum ovl_copyop
• function Copyright
• function with_ovl_creds
• function ovl_change_flags
• function ovl_file_free
• function ovl_is_real_file
• function ovl_open
• function ovl_release
• function ovl_llseek
• function ovl_file_modified
• function ovl_file_end_write
• function ovl_file_accessed
• function ovl_read_iter
• function ovl_write_iter
• function ovl_splice_read
• function iter_file_splice_write
• function ovl_fsync
• function ovl_mmap
• function ovl_fallocate
• function ovl_fadvise
• function ovl_copyfile
• function with_ovl_creds
• function ovl_copy_file_range
• function ovl_remap_file_range
• function ovl_flush

Annotated Snippet

const struct file_operations ovl_file_operations = {
	.open		= ovl_open,
	.release	= ovl_release,
	.llseek		= ovl_llseek,
	.read_iter	= ovl_read_iter,
	.write_iter	= ovl_write_iter,
	.fsync		= ovl_fsync,
	.mmap		= ovl_mmap,
	.fallocate	= ovl_fallocate,
	.fadvise	= ovl_fadvise,
	.flush		= ovl_flush,
	.splice_read    = ovl_splice_read,
	.splice_write   = ovl_splice_write,

	.copy_file_range	= ovl_copy_file_range,
	.remap_file_range	= ovl_remap_file_range,
	.setlease		= generic_setlease,
};

Annotation

• Immediate include surface: `linux/cred.h`, `linux/file.h`, `linux/filelock.h`, `linux/mount.h`, `linux/xattr.h`, `linux/uio.h`, `linux/uaccess.h`, `linux/security.h`.
• Detected declarations: `struct ovl_file`, `enum ovl_copyop`, `function Copyright`, `function with_ovl_creds`, `function ovl_change_flags`, `function ovl_file_free`, `function ovl_is_real_file`, `function ovl_open`, `function ovl_release`, `function ovl_llseek`.
• 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.