fs/dlm/user.c
Source file repositories/reference/linux-study-clean/fs/dlm/user.c
File Facts
- System
- Linux kernel
- Corpus path
fs/dlm/user.c- Extension
.c- Size
- 24669 bytes
- Lines
- 990
- 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
linux/miscdevice.hlinux/init.hlinux/wait.hlinux/file.hlinux/fs.hlinux/poll.hlinux/signal.hlinux/spinlock.hlinux/dlm.hlinux/dlm_device.hlinux/slab.hlinux/sched/signal.htrace/events/dlm.hdlm_internal.hlockspace.hlock.hlvb_table.huser.hast.hconfig.hmemory.h
Detected Declarations
struct dlm_lock_params32struct dlm_write_request32struct dlm_lksb32struct dlm_lock_result32function compat_inputfunction compat_outputfunction lkb_is_endoflifefunction dlm_user_add_astfunction device_user_lockfunction device_user_unlockfunction device_user_deadlockfunction dlm_device_registerfunction dlm_device_deregisterfunction device_user_purgefunction device_create_lockspacefunction device_remove_lockspacefunction check_versionfunction device_writefunction device_openfunction device_closefunction copy_result_to_userfunction dlm_user_convertfunction copy_version_to_userfunction device_readfunction device_pollfunction dlm_user_daemon_availablefunction ctl_device_openfunction ctl_device_closefunction monitor_device_openfunction monitor_device_closefunction dlm_user_initfunction dlm_user_exit
Annotated Snippet
static const struct file_operations device_fops;
static atomic_t dlm_monitor_opened;
static int dlm_monitor_unused = 1;
#ifdef CONFIG_COMPAT
struct dlm_lock_params32 {
__u8 mode;
__u8 namelen;
__u16 unused;
__u32 flags;
__u32 lkid;
__u32 parent;
__u64 xid;
__u64 timeout;
__u32 castparam;
__u32 castaddr;
__u32 bastparam;
__u32 bastaddr;
__u32 lksb;
char lvb[DLM_USER_LVB_LEN];
char name[];
};
struct dlm_write_request32 {
__u32 version[3];
__u8 cmd;
__u8 is64bit;
__u8 unused[2];
union {
struct dlm_lock_params32 lock;
struct dlm_lspace_params lspace;
struct dlm_purge_params purge;
} i;
};
struct dlm_lksb32 {
__u32 sb_status;
__u32 sb_lkid;
__u8 sb_flags;
__u32 sb_lvbptr;
};
struct dlm_lock_result32 {
__u32 version[3];
__u32 length;
__u32 user_astaddr;
__u32 user_astparam;
__u32 user_lksb;
struct dlm_lksb32 lksb;
__u8 bast_mode;
__u8 unused[3];
/* Offsets may be zero if no data is present */
__u32 lvb_offset;
};
static void compat_input(struct dlm_write_request *kb,
struct dlm_write_request32 *kb32,
int namelen)
{
kb->version[0] = kb32->version[0];
kb->version[1] = kb32->version[1];
kb->version[2] = kb32->version[2];
kb->cmd = kb32->cmd;
kb->is64bit = kb32->is64bit;
if (kb->cmd == DLM_USER_CREATE_LOCKSPACE ||
kb->cmd == DLM_USER_REMOVE_LOCKSPACE) {
kb->i.lspace.flags = kb32->i.lspace.flags;
kb->i.lspace.minor = kb32->i.lspace.minor;
memcpy(kb->i.lspace.name, kb32->i.lspace.name, namelen);
} else if (kb->cmd == DLM_USER_PURGE) {
kb->i.purge.nodeid = kb32->i.purge.nodeid;
kb->i.purge.pid = kb32->i.purge.pid;
} else {
kb->i.lock.mode = kb32->i.lock.mode;
kb->i.lock.namelen = kb32->i.lock.namelen;
kb->i.lock.flags = kb32->i.lock.flags;
kb->i.lock.lkid = kb32->i.lock.lkid;
kb->i.lock.parent = kb32->i.lock.parent;
kb->i.lock.xid = kb32->i.lock.xid;
kb->i.lock.timeout = kb32->i.lock.timeout;
kb->i.lock.castparam = (__user void *)(long)kb32->i.lock.castparam;
kb->i.lock.castaddr = (__user void *)(long)kb32->i.lock.castaddr;
kb->i.lock.bastparam = (__user void *)(long)kb32->i.lock.bastparam;
kb->i.lock.bastaddr = (__user void *)(long)kb32->i.lock.bastaddr;
kb->i.lock.lksb = (__user void *)(long)kb32->i.lock.lksb;
memcpy(kb->i.lock.lvb, kb32->i.lock.lvb, DLM_USER_LVB_LEN);
memcpy(kb->i.lock.name, kb32->i.lock.name, namelen);
Annotation
- Immediate include surface: `linux/miscdevice.h`, `linux/init.h`, `linux/wait.h`, `linux/file.h`, `linux/fs.h`, `linux/poll.h`, `linux/signal.h`, `linux/spinlock.h`.
- Detected declarations: `struct dlm_lock_params32`, `struct dlm_write_request32`, `struct dlm_lksb32`, `struct dlm_lock_result32`, `function compat_input`, `function compat_output`, `function lkb_is_endoflife`, `function dlm_user_add_ast`, `function device_user_lock`, `function device_user_unlock`.
- 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.