fs/fuse/file.c

File Facts

System

Linux kernel

Corpus path

fs/fuse/file.c

Extension

.c

Size

80449 bytes

Lines

3143

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.
• 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

• fuse_i.h
• dev.h
• linux/pagemap.h
• linux/slab.h
• linux/kernel.h
• linux/sched.h
• linux/sched/signal.h
• linux/module.h
• linux/swap.h
• linux/falloc.h
• linux/uio.h
• linux/fs.h
• linux/filelock.h
• linux/splice.h
• linux/task_io_accounting_ops.h
• linux/iomap.h

Detected Declarations

• struct fuse_writepage_args
• struct fuse_fill_read_data
• struct fuse_fill_wb_data
• function Copyright
• function fuse_file_free
• function fuse_release_end
• function fuse_file_put
• function fuse_do_open
• function fuse_link_write_file
• function fuse_finish_open
• function fuse_truncate_update_attr
• function fuse_open
• function fuse_prepare_release
• function fuse_file_release
• function fuse_release_common
• function fuse_release
• function fuse_sync_release
• function fuse_lock_owner_id
• function fuse_sync_writes
• function fuse_flush
• function fuse_fsync_common
• function fuse_fsync
• function fuse_read_args_fill
• function fuse_release_user_pages
• function fuse_io_release
• function fuse_get_res_by_io
• function fuse_aio_invalidate_worker
• function completed
• function fuse_io_free
• function fuse_aio_complete_req
• function fuse_async_req_send
• function fuse_send_read
• function fuse_read_update_size
• function fuse_short_read
• function fuse_do_readfolio
• function fuse_iomap_begin
• function fuse_handle_readahead
• function fuse_iomap_read_folio_range_async
• function fuse_iomap_submit_read
• function fuse_read_folio
• function fuse_iomap_read_folio_range
• function fuse_readpages_end
• function fuse_send_readpages
• function fuse_readahead
• function fuse_cache_read_iter
• function fuse_write_args_fill
• function fuse_write_flags
• function fuse_send_write

Annotated Snippet

static const struct file_operations fuse_file_operations = {
	.llseek		= fuse_file_llseek,
	.read_iter	= fuse_file_read_iter,
	.write_iter	= fuse_file_write_iter,
	.mmap		= fuse_file_mmap,
	.open		= fuse_open,
	.flush		= fuse_flush,
	.release	= fuse_release,
	.fsync		= fuse_fsync,
	.lock		= fuse_file_lock,
	.get_unmapped_area = thp_get_unmapped_area,
	.flock		= fuse_file_flock,
	.splice_read	= fuse_splice_read,
	.splice_write	= fuse_splice_write,
	.unlocked_ioctl	= fuse_file_ioctl,
	.compat_ioctl	= fuse_file_compat_ioctl,
	.poll		= fuse_file_poll,
	.fallocate	= fuse_file_fallocate,
	.copy_file_range = fuse_copy_file_range,
	.setlease	= generic_setlease,
};

static const struct address_space_operations fuse_file_aops  = {
	.read_folio	= fuse_read_folio,
	.readahead	= fuse_readahead,
	.writepages	= fuse_writepages,
	.launder_folio	= fuse_launder_folio,
	.dirty_folio	= iomap_dirty_folio,
	.release_folio	= iomap_release_folio,
	.invalidate_folio = iomap_invalidate_folio,
	.is_partially_uptodate = iomap_is_partially_uptodate,
	.migrate_folio	= filemap_migrate_folio,
	.bmap		= fuse_bmap,
	.direct_IO	= fuse_direct_IO,
};

void fuse_init_file_inode(struct inode *inode, unsigned int flags)
{
	struct fuse_inode *fi = get_fuse_inode(inode);
	struct fuse_conn *fc = get_fuse_conn(inode);

	inode->i_fop = &fuse_file_operations;
	inode->i_data.a_ops = &fuse_file_aops;
	if (fc->writeback_cache)
		mapping_set_writeback_may_deadlock_on_reclaim(&inode->i_data);

	INIT_LIST_HEAD(&fi->write_files);
	INIT_LIST_HEAD(&fi->queued_writes);
	fi->writectr = 0;
	fi->iocachectr = 0;
	init_waitqueue_head(&fi->page_waitq);
	init_waitqueue_head(&fi->direct_io_waitq);

	if (IS_ENABLED(CONFIG_FUSE_DAX))
		fuse_dax_inode_init(inode, flags);
}

Annotation

• Immediate include surface: `fuse_i.h`, `dev.h`, `linux/pagemap.h`, `linux/slab.h`, `linux/kernel.h`, `linux/sched.h`, `linux/sched/signal.h`, `linux/module.h`.
• Detected declarations: `struct fuse_writepage_args`, `struct fuse_fill_read_data`, `struct fuse_fill_wb_data`, `function Copyright`, `function fuse_file_free`, `function fuse_release_end`, `function fuse_file_put`, `function fuse_do_open`, `function fuse_link_write_file`, `function fuse_finish_open`.
• 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.
• 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.