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OpenCloudOS-Kernel/fs/ceph/locks.c

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#include <linux/ceph/ceph_debug.h>
#include <linux/file.h>
#include <linux/namei.h>
#include "super.h"
#include "mds_client.h"
#include <linux/ceph/pagelist.h>
/**
* Implement fcntl and flock locking functions.
*/
static int ceph_lock_message(u8 lock_type, u16 operation, struct file *file,
int cmd, u8 wait, struct file_lock *fl)
{
struct inode *inode = file_inode(file);
struct ceph_mds_client *mdsc =
ceph_sb_to_client(inode->i_sb)->mdsc;
struct ceph_mds_request *req;
int err;
u64 length = 0;
req = ceph_mdsc_create_request(mdsc, operation, USE_AUTH_MDS);
if (IS_ERR(req))
return PTR_ERR(req);
req->r_inode = inode;
ihold(inode);
/* mds requires start and length rather than start and end */
if (LLONG_MAX == fl->fl_end)
length = 0;
else
length = fl->fl_end - fl->fl_start + 1;
dout("ceph_lock_message: rule: %d, op: %d, pid: %llu, start: %llu, "
"length: %llu, wait: %d, type: %d", (int)lock_type,
(int)operation, (u64)fl->fl_pid, fl->fl_start,
length, wait, fl->fl_type);
req->r_args.filelock_change.rule = lock_type;
req->r_args.filelock_change.type = cmd;
req->r_args.filelock_change.pid = cpu_to_le64((u64)fl->fl_pid);
/* This should be adjusted, but I'm not sure if
namespaces actually get id numbers*/
req->r_args.filelock_change.pid_namespace =
cpu_to_le64((u64)(unsigned long)fl->fl_nspid);
req->r_args.filelock_change.start = cpu_to_le64(fl->fl_start);
req->r_args.filelock_change.length = cpu_to_le64(length);
req->r_args.filelock_change.wait = wait;
err = ceph_mdsc_do_request(mdsc, inode, req);
if ( operation == CEPH_MDS_OP_GETFILELOCK){
fl->fl_pid = le64_to_cpu(req->r_reply_info.filelock_reply->pid);
if (CEPH_LOCK_SHARED == req->r_reply_info.filelock_reply->type)
fl->fl_type = F_RDLCK;
else if (CEPH_LOCK_EXCL == req->r_reply_info.filelock_reply->type)
fl->fl_type = F_WRLCK;
else
fl->fl_type = F_UNLCK;
fl->fl_start = le64_to_cpu(req->r_reply_info.filelock_reply->start);
length = le64_to_cpu(req->r_reply_info.filelock_reply->start) +
le64_to_cpu(req->r_reply_info.filelock_reply->length);
if (length >= 1)
fl->fl_end = length -1;
else
fl->fl_end = 0;
}
ceph_mdsc_put_request(req);
dout("ceph_lock_message: rule: %d, op: %d, pid: %llu, start: %llu, "
"length: %llu, wait: %d, type: %d, err code %d", (int)lock_type,
(int)operation, (u64)fl->fl_pid, fl->fl_start,
length, wait, fl->fl_type, err);
return err;
}
/**
* Attempt to set an fcntl lock.
* For now, this just goes away to the server. Later it may be more awesome.
*/
int ceph_lock(struct file *file, int cmd, struct file_lock *fl)
{
u8 lock_cmd;
int err;
u8 wait = 0;
u16 op = CEPH_MDS_OP_SETFILELOCK;
fl->fl_nspid = get_pid(task_tgid(current));
dout("ceph_lock, fl_pid:%d", fl->fl_pid);
/* set wait bit as appropriate, then make command as Ceph expects it*/
if (F_SETLKW == cmd)
wait = 1;
if (F_GETLK == cmd)
op = CEPH_MDS_OP_GETFILELOCK;
if (F_RDLCK == fl->fl_type)
lock_cmd = CEPH_LOCK_SHARED;
else if (F_WRLCK == fl->fl_type)
lock_cmd = CEPH_LOCK_EXCL;
else
lock_cmd = CEPH_LOCK_UNLOCK;
err = ceph_lock_message(CEPH_LOCK_FCNTL, op, file, lock_cmd, wait, fl);
if (!err) {
if ( op != CEPH_MDS_OP_GETFILELOCK ){
dout("mds locked, locking locally");
err = posix_lock_file(file, fl, NULL);
if (err && (CEPH_MDS_OP_SETFILELOCK == op)) {
/* undo! This should only happen if
* the kernel detects local
* deadlock. */
ceph_lock_message(CEPH_LOCK_FCNTL, op, file,
CEPH_LOCK_UNLOCK, 0, fl);
dout("got %d on posix_lock_file, undid lock",
err);
}
}
} else if (err == -ERESTARTSYS) {
dout("undoing lock\n");
ceph_lock_message(CEPH_LOCK_FCNTL, op, file,
CEPH_LOCK_UNLOCK, 0, fl);
}
return err;
}
int ceph_flock(struct file *file, int cmd, struct file_lock *fl)
{
u8 lock_cmd;
int err;
u8 wait = 1;
fl->fl_nspid = get_pid(task_tgid(current));
dout("ceph_flock, fl_pid:%d", fl->fl_pid);
/* set wait bit, then clear it out of cmd*/
if (cmd & LOCK_NB)
wait = 0;
cmd = cmd & (LOCK_SH | LOCK_EX | LOCK_UN);
/* set command sequence that Ceph wants to see:
shared lock, exclusive lock, or unlock */
if (LOCK_SH == cmd)
lock_cmd = CEPH_LOCK_SHARED;
else if (LOCK_EX == cmd)
lock_cmd = CEPH_LOCK_EXCL;
else
lock_cmd = CEPH_LOCK_UNLOCK;
err = ceph_lock_message(CEPH_LOCK_FLOCK, CEPH_MDS_OP_SETFILELOCK,
file, lock_cmd, wait, fl);
if (!err) {
err = flock_lock_file_wait(file, fl);
if (err) {
ceph_lock_message(CEPH_LOCK_FLOCK,
CEPH_MDS_OP_SETFILELOCK,
file, CEPH_LOCK_UNLOCK, 0, fl);
dout("got %d on flock_lock_file_wait, undid lock", err);
}
} else if (err == -ERESTARTSYS) {
dout("undoing lock\n");
ceph_lock_message(CEPH_LOCK_FLOCK,
CEPH_MDS_OP_SETFILELOCK,
file, CEPH_LOCK_UNLOCK, 0, fl);
}
return err;
}
/**
* Must be called with BKL already held. Fills in the passed
* counter variables, so you can prepare pagelist metadata before calling
* ceph_encode_locks.
*/
void ceph_count_locks(struct inode *inode, int *fcntl_count, int *flock_count)
{
struct file_lock *lock;
*fcntl_count = 0;
*flock_count = 0;
for (lock = inode->i_flock; lock != NULL; lock = lock->fl_next) {
if (lock->fl_flags & FL_POSIX)
++(*fcntl_count);
else if (lock->fl_flags & FL_FLOCK)
++(*flock_count);
}
dout("counted %d flock locks and %d fcntl locks",
*flock_count, *fcntl_count);
}
/**
* Encode the flock and fcntl locks for the given inode into the pagelist.
* Format is: #fcntl locks, sequential fcntl locks, #flock locks,
* sequential flock locks.
* Must be called with lock_flocks() already held.
* If we encounter more of a specific lock type than expected,
* we return the value 1.
*/
int ceph_encode_locks(struct inode *inode, struct ceph_pagelist *pagelist,
int num_fcntl_locks, int num_flock_locks)
{
struct file_lock *lock;
struct ceph_filelock cephlock;
int err = 0;
int seen_fcntl = 0;
int seen_flock = 0;
dout("encoding %d flock and %d fcntl locks", num_flock_locks,
num_fcntl_locks);
err = ceph_pagelist_append(pagelist, &num_fcntl_locks, sizeof(u32));
if (err)
goto fail;
for (lock = inode->i_flock; lock != NULL; lock = lock->fl_next) {
if (lock->fl_flags & FL_POSIX) {
++seen_fcntl;
if (seen_fcntl > num_fcntl_locks) {
err = -ENOSPC;
goto fail;
}
err = lock_to_ceph_filelock(lock, &cephlock);
if (err)
goto fail;
err = ceph_pagelist_append(pagelist, &cephlock,
sizeof(struct ceph_filelock));
}
if (err)
goto fail;
}
err = ceph_pagelist_append(pagelist, &num_flock_locks, sizeof(u32));
if (err)
goto fail;
for (lock = inode->i_flock; lock != NULL; lock = lock->fl_next) {
if (lock->fl_flags & FL_FLOCK) {
++seen_flock;
if (seen_flock > num_flock_locks) {
err = -ENOSPC;
goto fail;
}
err = lock_to_ceph_filelock(lock, &cephlock);
if (err)
goto fail;
err = ceph_pagelist_append(pagelist, &cephlock,
sizeof(struct ceph_filelock));
}
if (err)
goto fail;
}
fail:
return err;
}
/*
* Given a pointer to a lock, convert it to a ceph filelock
*/
int lock_to_ceph_filelock(struct file_lock *lock,
struct ceph_filelock *cephlock)
{
int err = 0;
cephlock->start = cpu_to_le64(lock->fl_start);
cephlock->length = cpu_to_le64(lock->fl_end - lock->fl_start + 1);
cephlock->client = cpu_to_le64(0);
cephlock->pid = cpu_to_le64(lock->fl_pid);
cephlock->pid_namespace =
cpu_to_le64((u64)(unsigned long)lock->fl_nspid);
switch (lock->fl_type) {
case F_RDLCK:
cephlock->type = CEPH_LOCK_SHARED;
break;
case F_WRLCK:
cephlock->type = CEPH_LOCK_EXCL;
break;
case F_UNLCK:
cephlock->type = CEPH_LOCK_UNLOCK;
break;
default:
dout("Have unknown lock type %d", lock->fl_type);
err = -EINVAL;
}
return err;
}
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