fs/nfs/flexfilelayout/flexfilelayout.c

File Facts

System

Linux kernel

Corpus path

fs/nfs/flexfilelayout/flexfilelayout.c

Extension

.c

Size

81266 bytes

Lines

3037

Domain

Core OS

Bucket

VFS And Filesystem Core

Inferred role

Core OS: exported/initcall integration point

Status

integration 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.
• Exports symbols or registers init work; inspect boot/module ordering and who consumes the exported contract.
• 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/nfs_fs.h
• linux/nfs_mount.h
• linux/nfs_page.h
• linux/module.h
• linux/file.h
• linux/sched/mm.h
• linux/sunrpc/metrics.h
• flexfilelayout.h
• ../nfs4session.h
• ../nfs4idmap.h
• ../internal.h
• ../delegation.h
• ../nfs4trace.h
• ../iostat.h
• ../nfs.h
• ../nfs42.h

Detected Declarations

• enum nfs4_ff_op_type
• function ff_layout_alloc_layout_hdr
• function ff_layout_free_layout_hdr
• function list_for_each_entry_safe
• function decode_pnfs_stateid
• function decode_deviceid
• function decode_nfs_fh
• function nfs_map_name_to_uid
• function ff_local_open_fh
• function ff_dss_match_fh
• function ff_mirror_match_fh
• function ff_mirror_match_devid
• function ff_layout_add_mirror
• function ff_layout_remove_mirror
• function ff_layout_free_mirror
• function ff_layout_put_mirror
• function ff_layout_free_mirror_array
• function _ff_layout_free_lseg
• function ff_lseg_match_mirrors
• function ff_lseg_range_is_after
• function ff_lseg_merge
• function ff_layout_add_lseg
• function ff_mirror_efficiency_sum
• function ff_layout_sort_mirrors
• function ff_layout_alloc_lseg
• function ff_layout_free_lseg
• function calc_commit_idx
• function calc_mirror_idx_from_commit
• function calc_dss_id_from_commit
• function nfs4_ff_start_busy_timer
• function nfs4_ff_end_busy_timer
• function nfs4_ff_layoutstat_start_io
• function nfs4_ff_layout_stat_io_update_requested
• function nfs4_ff_layout_stat_io_update_completed
• function nfs4_ff_layout_stat_io_start_read
• function nfs4_ff_layout_stat_io_end_read
• function nfs4_ff_layout_stat_io_start_write
• function nfs4_ff_layout_stat_io_end_write
• function ff_layout_mark_ds_unreachable
• function ff_layout_mark_ds_reachable
• function ff_layout_choose_ds_for_read
• function ff_layout_choose_any_ds_for_read
• function ff_layout_choose_valid_ds_for_read
• function ff_layout_choose_best_ds_for_read
• function ff_layout_get_ds_for_read
• function ff_layout_pg_get_read
• function ff_layout_lseg_is_striped
• function ff_layout_pg_test

Annotated Snippet

module_init(nfs4flexfilelayout_init);
module_exit(nfs4flexfilelayout_exit);

module_param(io_maxretrans, ushort, 0644);
MODULE_PARM_DESC(io_maxretrans, "The  number of times the NFSv4.1 client "
			"retries an I/O request before returning an error. ");

Annotation

• Immediate include surface: `linux/nfs_fs.h`, `linux/nfs_mount.h`, `linux/nfs_page.h`, `linux/module.h`, `linux/file.h`, `linux/sched/mm.h`, `linux/sunrpc/metrics.h`, `flexfilelayout.h`.
• Detected declarations: `enum nfs4_ff_op_type`, `function ff_layout_alloc_layout_hdr`, `function ff_layout_free_layout_hdr`, `function list_for_each_entry_safe`, `function decode_pnfs_stateid`, `function decode_deviceid`, `function decode_nfs_fh`, `function nfs_map_name_to_uid`, `function ff_local_open_fh`, `function ff_dss_match_fh`.
• Atlas domain: Core OS / VFS And Filesystem Core.
• Implementation status: integration 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.