forked from Qortal/Brooklyn
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
864 lines
22 KiB
864 lines
22 KiB
// SPDX-License-Identifier: GPL-2.0-only |
|
/* |
|
* linux/fs/lockd/clntproc.c |
|
* |
|
* RPC procedures for the client side NLM implementation |
|
* |
|
* Copyright (C) 1996, Olaf Kirch <[email protected]> |
|
*/ |
|
|
|
#include <linux/module.h> |
|
#include <linux/slab.h> |
|
#include <linux/types.h> |
|
#include <linux/errno.h> |
|
#include <linux/fs.h> |
|
#include <linux/nfs_fs.h> |
|
#include <linux/utsname.h> |
|
#include <linux/freezer.h> |
|
#include <linux/sunrpc/clnt.h> |
|
#include <linux/sunrpc/svc.h> |
|
#include <linux/lockd/lockd.h> |
|
|
|
#define NLMDBG_FACILITY NLMDBG_CLIENT |
|
#define NLMCLNT_GRACE_WAIT (5*HZ) |
|
#define NLMCLNT_POLL_TIMEOUT (30*HZ) |
|
#define NLMCLNT_MAX_RETRIES 3 |
|
|
|
static int nlmclnt_test(struct nlm_rqst *, struct file_lock *); |
|
static int nlmclnt_lock(struct nlm_rqst *, struct file_lock *); |
|
static int nlmclnt_unlock(struct nlm_rqst *, struct file_lock *); |
|
static int nlm_stat_to_errno(__be32 stat); |
|
static void nlmclnt_locks_init_private(struct file_lock *fl, struct nlm_host *host); |
|
static int nlmclnt_cancel(struct nlm_host *, int , struct file_lock *); |
|
|
|
static const struct rpc_call_ops nlmclnt_unlock_ops; |
|
static const struct rpc_call_ops nlmclnt_cancel_ops; |
|
|
|
/* |
|
* Cookie counter for NLM requests |
|
*/ |
|
static atomic_t nlm_cookie = ATOMIC_INIT(0x1234); |
|
|
|
void nlmclnt_next_cookie(struct nlm_cookie *c) |
|
{ |
|
u32 cookie = atomic_inc_return(&nlm_cookie); |
|
|
|
memcpy(c->data, &cookie, 4); |
|
c->len=4; |
|
} |
|
|
|
static struct nlm_lockowner * |
|
nlmclnt_get_lockowner(struct nlm_lockowner *lockowner) |
|
{ |
|
refcount_inc(&lockowner->count); |
|
return lockowner; |
|
} |
|
|
|
static void nlmclnt_put_lockowner(struct nlm_lockowner *lockowner) |
|
{ |
|
if (!refcount_dec_and_lock(&lockowner->count, &lockowner->host->h_lock)) |
|
return; |
|
list_del(&lockowner->list); |
|
spin_unlock(&lockowner->host->h_lock); |
|
nlmclnt_release_host(lockowner->host); |
|
kfree(lockowner); |
|
} |
|
|
|
static inline int nlm_pidbusy(struct nlm_host *host, uint32_t pid) |
|
{ |
|
struct nlm_lockowner *lockowner; |
|
list_for_each_entry(lockowner, &host->h_lockowners, list) { |
|
if (lockowner->pid == pid) |
|
return -EBUSY; |
|
} |
|
return 0; |
|
} |
|
|
|
static inline uint32_t __nlm_alloc_pid(struct nlm_host *host) |
|
{ |
|
uint32_t res; |
|
do { |
|
res = host->h_pidcount++; |
|
} while (nlm_pidbusy(host, res) < 0); |
|
return res; |
|
} |
|
|
|
static struct nlm_lockowner *__nlmclnt_find_lockowner(struct nlm_host *host, fl_owner_t owner) |
|
{ |
|
struct nlm_lockowner *lockowner; |
|
list_for_each_entry(lockowner, &host->h_lockowners, list) { |
|
if (lockowner->owner != owner) |
|
continue; |
|
return nlmclnt_get_lockowner(lockowner); |
|
} |
|
return NULL; |
|
} |
|
|
|
static struct nlm_lockowner *nlmclnt_find_lockowner(struct nlm_host *host, fl_owner_t owner) |
|
{ |
|
struct nlm_lockowner *res, *new = NULL; |
|
|
|
spin_lock(&host->h_lock); |
|
res = __nlmclnt_find_lockowner(host, owner); |
|
if (res == NULL) { |
|
spin_unlock(&host->h_lock); |
|
new = kmalloc(sizeof(*new), GFP_KERNEL); |
|
spin_lock(&host->h_lock); |
|
res = __nlmclnt_find_lockowner(host, owner); |
|
if (res == NULL && new != NULL) { |
|
res = new; |
|
refcount_set(&new->count, 1); |
|
new->owner = owner; |
|
new->pid = __nlm_alloc_pid(host); |
|
new->host = nlm_get_host(host); |
|
list_add(&new->list, &host->h_lockowners); |
|
new = NULL; |
|
} |
|
} |
|
spin_unlock(&host->h_lock); |
|
kfree(new); |
|
return res; |
|
} |
|
|
|
/* |
|
* Initialize arguments for TEST/LOCK/UNLOCK/CANCEL calls |
|
*/ |
|
static void nlmclnt_setlockargs(struct nlm_rqst *req, struct file_lock *fl) |
|
{ |
|
struct nlm_args *argp = &req->a_args; |
|
struct nlm_lock *lock = &argp->lock; |
|
char *nodename = req->a_host->h_rpcclnt->cl_nodename; |
|
|
|
nlmclnt_next_cookie(&argp->cookie); |
|
memcpy(&lock->fh, NFS_FH(locks_inode(fl->fl_file)), sizeof(struct nfs_fh)); |
|
lock->caller = nodename; |
|
lock->oh.data = req->a_owner; |
|
lock->oh.len = snprintf(req->a_owner, sizeof(req->a_owner), "%u@%s", |
|
(unsigned int)fl->fl_u.nfs_fl.owner->pid, |
|
nodename); |
|
lock->svid = fl->fl_u.nfs_fl.owner->pid; |
|
lock->fl.fl_start = fl->fl_start; |
|
lock->fl.fl_end = fl->fl_end; |
|
lock->fl.fl_type = fl->fl_type; |
|
} |
|
|
|
static void nlmclnt_release_lockargs(struct nlm_rqst *req) |
|
{ |
|
WARN_ON_ONCE(req->a_args.lock.fl.fl_ops != NULL); |
|
} |
|
|
|
/** |
|
* nlmclnt_proc - Perform a single client-side lock request |
|
* @host: address of a valid nlm_host context representing the NLM server |
|
* @cmd: fcntl-style file lock operation to perform |
|
* @fl: address of arguments for the lock operation |
|
* @data: address of data to be sent to callback operations |
|
* |
|
*/ |
|
int nlmclnt_proc(struct nlm_host *host, int cmd, struct file_lock *fl, void *data) |
|
{ |
|
struct nlm_rqst *call; |
|
int status; |
|
const struct nlmclnt_operations *nlmclnt_ops = host->h_nlmclnt_ops; |
|
|
|
call = nlm_alloc_call(host); |
|
if (call == NULL) |
|
return -ENOMEM; |
|
|
|
if (nlmclnt_ops && nlmclnt_ops->nlmclnt_alloc_call) |
|
nlmclnt_ops->nlmclnt_alloc_call(data); |
|
|
|
nlmclnt_locks_init_private(fl, host); |
|
if (!fl->fl_u.nfs_fl.owner) { |
|
/* lockowner allocation has failed */ |
|
nlmclnt_release_call(call); |
|
return -ENOMEM; |
|
} |
|
/* Set up the argument struct */ |
|
nlmclnt_setlockargs(call, fl); |
|
call->a_callback_data = data; |
|
|
|
if (IS_SETLK(cmd) || IS_SETLKW(cmd)) { |
|
if (fl->fl_type != F_UNLCK) { |
|
call->a_args.block = IS_SETLKW(cmd) ? 1 : 0; |
|
status = nlmclnt_lock(call, fl); |
|
} else |
|
status = nlmclnt_unlock(call, fl); |
|
} else if (IS_GETLK(cmd)) |
|
status = nlmclnt_test(call, fl); |
|
else |
|
status = -EINVAL; |
|
fl->fl_ops->fl_release_private(fl); |
|
fl->fl_ops = NULL; |
|
|
|
dprintk("lockd: clnt proc returns %d\n", status); |
|
return status; |
|
} |
|
EXPORT_SYMBOL_GPL(nlmclnt_proc); |
|
|
|
/* |
|
* Allocate an NLM RPC call struct |
|
*/ |
|
struct nlm_rqst *nlm_alloc_call(struct nlm_host *host) |
|
{ |
|
struct nlm_rqst *call; |
|
|
|
for(;;) { |
|
call = kzalloc(sizeof(*call), GFP_KERNEL); |
|
if (call != NULL) { |
|
refcount_set(&call->a_count, 1); |
|
locks_init_lock(&call->a_args.lock.fl); |
|
locks_init_lock(&call->a_res.lock.fl); |
|
call->a_host = nlm_get_host(host); |
|
return call; |
|
} |
|
if (signalled()) |
|
break; |
|
printk("nlm_alloc_call: failed, waiting for memory\n"); |
|
schedule_timeout_interruptible(5*HZ); |
|
} |
|
return NULL; |
|
} |
|
|
|
void nlmclnt_release_call(struct nlm_rqst *call) |
|
{ |
|
const struct nlmclnt_operations *nlmclnt_ops = call->a_host->h_nlmclnt_ops; |
|
|
|
if (!refcount_dec_and_test(&call->a_count)) |
|
return; |
|
if (nlmclnt_ops && nlmclnt_ops->nlmclnt_release_call) |
|
nlmclnt_ops->nlmclnt_release_call(call->a_callback_data); |
|
nlmclnt_release_host(call->a_host); |
|
nlmclnt_release_lockargs(call); |
|
kfree(call); |
|
} |
|
|
|
static void nlmclnt_rpc_release(void *data) |
|
{ |
|
nlmclnt_release_call(data); |
|
} |
|
|
|
static int nlm_wait_on_grace(wait_queue_head_t *queue) |
|
{ |
|
DEFINE_WAIT(wait); |
|
int status = -EINTR; |
|
|
|
prepare_to_wait(queue, &wait, TASK_INTERRUPTIBLE); |
|
if (!signalled ()) { |
|
schedule_timeout(NLMCLNT_GRACE_WAIT); |
|
try_to_freeze(); |
|
if (!signalled ()) |
|
status = 0; |
|
} |
|
finish_wait(queue, &wait); |
|
return status; |
|
} |
|
|
|
/* |
|
* Generic NLM call |
|
*/ |
|
static int |
|
nlmclnt_call(const struct cred *cred, struct nlm_rqst *req, u32 proc) |
|
{ |
|
struct nlm_host *host = req->a_host; |
|
struct rpc_clnt *clnt; |
|
struct nlm_args *argp = &req->a_args; |
|
struct nlm_res *resp = &req->a_res; |
|
struct rpc_message msg = { |
|
.rpc_argp = argp, |
|
.rpc_resp = resp, |
|
.rpc_cred = cred, |
|
}; |
|
int status; |
|
|
|
dprintk("lockd: call procedure %d on %s\n", |
|
(int)proc, host->h_name); |
|
|
|
do { |
|
if (host->h_reclaiming && !argp->reclaim) |
|
goto in_grace_period; |
|
|
|
/* If we have no RPC client yet, create one. */ |
|
if ((clnt = nlm_bind_host(host)) == NULL) |
|
return -ENOLCK; |
|
msg.rpc_proc = &clnt->cl_procinfo[proc]; |
|
|
|
/* Perform the RPC call. If an error occurs, try again */ |
|
if ((status = rpc_call_sync(clnt, &msg, 0)) < 0) { |
|
dprintk("lockd: rpc_call returned error %d\n", -status); |
|
switch (status) { |
|
case -EPROTONOSUPPORT: |
|
status = -EINVAL; |
|
break; |
|
case -ECONNREFUSED: |
|
case -ETIMEDOUT: |
|
case -ENOTCONN: |
|
nlm_rebind_host(host); |
|
status = -EAGAIN; |
|
break; |
|
case -ERESTARTSYS: |
|
return signalled () ? -EINTR : status; |
|
default: |
|
break; |
|
} |
|
break; |
|
} else |
|
if (resp->status == nlm_lck_denied_grace_period) { |
|
dprintk("lockd: server in grace period\n"); |
|
if (argp->reclaim) { |
|
printk(KERN_WARNING |
|
"lockd: spurious grace period reject?!\n"); |
|
return -ENOLCK; |
|
} |
|
} else { |
|
if (!argp->reclaim) { |
|
/* We appear to be out of the grace period */ |
|
wake_up_all(&host->h_gracewait); |
|
} |
|
dprintk("lockd: server returns status %d\n", |
|
ntohl(resp->status)); |
|
return 0; /* Okay, call complete */ |
|
} |
|
|
|
in_grace_period: |
|
/* |
|
* The server has rebooted and appears to be in the grace |
|
* period during which locks are only allowed to be |
|
* reclaimed. |
|
* We can only back off and try again later. |
|
*/ |
|
status = nlm_wait_on_grace(&host->h_gracewait); |
|
} while (status == 0); |
|
|
|
return status; |
|
} |
|
|
|
/* |
|
* Generic NLM call, async version. |
|
*/ |
|
static struct rpc_task *__nlm_async_call(struct nlm_rqst *req, u32 proc, struct rpc_message *msg, const struct rpc_call_ops *tk_ops) |
|
{ |
|
struct nlm_host *host = req->a_host; |
|
struct rpc_clnt *clnt; |
|
struct rpc_task_setup task_setup_data = { |
|
.rpc_message = msg, |
|
.callback_ops = tk_ops, |
|
.callback_data = req, |
|
.flags = RPC_TASK_ASYNC, |
|
}; |
|
|
|
dprintk("lockd: call procedure %d on %s (async)\n", |
|
(int)proc, host->h_name); |
|
|
|
/* If we have no RPC client yet, create one. */ |
|
clnt = nlm_bind_host(host); |
|
if (clnt == NULL) |
|
goto out_err; |
|
msg->rpc_proc = &clnt->cl_procinfo[proc]; |
|
task_setup_data.rpc_client = clnt; |
|
|
|
/* bootstrap and kick off the async RPC call */ |
|
return rpc_run_task(&task_setup_data); |
|
out_err: |
|
tk_ops->rpc_release(req); |
|
return ERR_PTR(-ENOLCK); |
|
} |
|
|
|
static int nlm_do_async_call(struct nlm_rqst *req, u32 proc, struct rpc_message *msg, const struct rpc_call_ops *tk_ops) |
|
{ |
|
struct rpc_task *task; |
|
|
|
task = __nlm_async_call(req, proc, msg, tk_ops); |
|
if (IS_ERR(task)) |
|
return PTR_ERR(task); |
|
rpc_put_task(task); |
|
return 0; |
|
} |
|
|
|
/* |
|
* NLM asynchronous call. |
|
*/ |
|
int nlm_async_call(struct nlm_rqst *req, u32 proc, const struct rpc_call_ops *tk_ops) |
|
{ |
|
struct rpc_message msg = { |
|
.rpc_argp = &req->a_args, |
|
.rpc_resp = &req->a_res, |
|
}; |
|
return nlm_do_async_call(req, proc, &msg, tk_ops); |
|
} |
|
|
|
int nlm_async_reply(struct nlm_rqst *req, u32 proc, const struct rpc_call_ops *tk_ops) |
|
{ |
|
struct rpc_message msg = { |
|
.rpc_argp = &req->a_res, |
|
}; |
|
return nlm_do_async_call(req, proc, &msg, tk_ops); |
|
} |
|
|
|
/* |
|
* NLM client asynchronous call. |
|
* |
|
* Note that although the calls are asynchronous, and are therefore |
|
* guaranteed to complete, we still always attempt to wait for |
|
* completion in order to be able to correctly track the lock |
|
* state. |
|
*/ |
|
static int nlmclnt_async_call(const struct cred *cred, struct nlm_rqst *req, u32 proc, const struct rpc_call_ops *tk_ops) |
|
{ |
|
struct rpc_message msg = { |
|
.rpc_argp = &req->a_args, |
|
.rpc_resp = &req->a_res, |
|
.rpc_cred = cred, |
|
}; |
|
struct rpc_task *task; |
|
int err; |
|
|
|
task = __nlm_async_call(req, proc, &msg, tk_ops); |
|
if (IS_ERR(task)) |
|
return PTR_ERR(task); |
|
err = rpc_wait_for_completion_task(task); |
|
rpc_put_task(task); |
|
return err; |
|
} |
|
|
|
/* |
|
* TEST for the presence of a conflicting lock |
|
*/ |
|
static int |
|
nlmclnt_test(struct nlm_rqst *req, struct file_lock *fl) |
|
{ |
|
int status; |
|
|
|
status = nlmclnt_call(nfs_file_cred(fl->fl_file), req, NLMPROC_TEST); |
|
if (status < 0) |
|
goto out; |
|
|
|
switch (req->a_res.status) { |
|
case nlm_granted: |
|
fl->fl_type = F_UNLCK; |
|
break; |
|
case nlm_lck_denied: |
|
/* |
|
* Report the conflicting lock back to the application. |
|
*/ |
|
fl->fl_start = req->a_res.lock.fl.fl_start; |
|
fl->fl_end = req->a_res.lock.fl.fl_end; |
|
fl->fl_type = req->a_res.lock.fl.fl_type; |
|
fl->fl_pid = -req->a_res.lock.fl.fl_pid; |
|
break; |
|
default: |
|
status = nlm_stat_to_errno(req->a_res.status); |
|
} |
|
out: |
|
nlmclnt_release_call(req); |
|
return status; |
|
} |
|
|
|
static void nlmclnt_locks_copy_lock(struct file_lock *new, struct file_lock *fl) |
|
{ |
|
spin_lock(&fl->fl_u.nfs_fl.owner->host->h_lock); |
|
new->fl_u.nfs_fl.state = fl->fl_u.nfs_fl.state; |
|
new->fl_u.nfs_fl.owner = nlmclnt_get_lockowner(fl->fl_u.nfs_fl.owner); |
|
list_add_tail(&new->fl_u.nfs_fl.list, &fl->fl_u.nfs_fl.owner->host->h_granted); |
|
spin_unlock(&fl->fl_u.nfs_fl.owner->host->h_lock); |
|
} |
|
|
|
static void nlmclnt_locks_release_private(struct file_lock *fl) |
|
{ |
|
spin_lock(&fl->fl_u.nfs_fl.owner->host->h_lock); |
|
list_del(&fl->fl_u.nfs_fl.list); |
|
spin_unlock(&fl->fl_u.nfs_fl.owner->host->h_lock); |
|
nlmclnt_put_lockowner(fl->fl_u.nfs_fl.owner); |
|
} |
|
|
|
static const struct file_lock_operations nlmclnt_lock_ops = { |
|
.fl_copy_lock = nlmclnt_locks_copy_lock, |
|
.fl_release_private = nlmclnt_locks_release_private, |
|
}; |
|
|
|
static void nlmclnt_locks_init_private(struct file_lock *fl, struct nlm_host *host) |
|
{ |
|
fl->fl_u.nfs_fl.state = 0; |
|
fl->fl_u.nfs_fl.owner = nlmclnt_find_lockowner(host, fl->fl_owner); |
|
INIT_LIST_HEAD(&fl->fl_u.nfs_fl.list); |
|
fl->fl_ops = &nlmclnt_lock_ops; |
|
} |
|
|
|
static int do_vfs_lock(struct file_lock *fl) |
|
{ |
|
return locks_lock_file_wait(fl->fl_file, fl); |
|
} |
|
|
|
/* |
|
* LOCK: Try to create a lock |
|
* |
|
* Programmer Harassment Alert |
|
* |
|
* When given a blocking lock request in a sync RPC call, the HPUX lockd |
|
* will faithfully return LCK_BLOCKED but never cares to notify us when |
|
* the lock could be granted. This way, our local process could hang |
|
* around forever waiting for the callback. |
|
* |
|
* Solution A: Implement busy-waiting |
|
* Solution B: Use the async version of the call (NLM_LOCK_{MSG,RES}) |
|
* |
|
* For now I am implementing solution A, because I hate the idea of |
|
* re-implementing lockd for a third time in two months. The async |
|
* calls shouldn't be too hard to do, however. |
|
* |
|
* This is one of the lovely things about standards in the NFS area: |
|
* they're so soft and squishy you can't really blame HP for doing this. |
|
*/ |
|
static int |
|
nlmclnt_lock(struct nlm_rqst *req, struct file_lock *fl) |
|
{ |
|
const struct cred *cred = nfs_file_cred(fl->fl_file); |
|
struct nlm_host *host = req->a_host; |
|
struct nlm_res *resp = &req->a_res; |
|
struct nlm_wait *block = NULL; |
|
unsigned char fl_flags = fl->fl_flags; |
|
unsigned char fl_type; |
|
int status = -ENOLCK; |
|
|
|
if (nsm_monitor(host) < 0) |
|
goto out; |
|
req->a_args.state = nsm_local_state; |
|
|
|
fl->fl_flags |= FL_ACCESS; |
|
status = do_vfs_lock(fl); |
|
fl->fl_flags = fl_flags; |
|
if (status < 0) |
|
goto out; |
|
|
|
block = nlmclnt_prepare_block(host, fl); |
|
again: |
|
/* |
|
* Initialise resp->status to a valid non-zero value, |
|
* since 0 == nlm_lck_granted |
|
*/ |
|
resp->status = nlm_lck_blocked; |
|
for(;;) { |
|
/* Reboot protection */ |
|
fl->fl_u.nfs_fl.state = host->h_state; |
|
status = nlmclnt_call(cred, req, NLMPROC_LOCK); |
|
if (status < 0) |
|
break; |
|
/* Did a reclaimer thread notify us of a server reboot? */ |
|
if (resp->status == nlm_lck_denied_grace_period) |
|
continue; |
|
if (resp->status != nlm_lck_blocked) |
|
break; |
|
/* Wait on an NLM blocking lock */ |
|
status = nlmclnt_block(block, req, NLMCLNT_POLL_TIMEOUT); |
|
if (status < 0) |
|
break; |
|
if (resp->status != nlm_lck_blocked) |
|
break; |
|
} |
|
|
|
/* if we were interrupted while blocking, then cancel the lock request |
|
* and exit |
|
*/ |
|
if (resp->status == nlm_lck_blocked) { |
|
if (!req->a_args.block) |
|
goto out_unlock; |
|
if (nlmclnt_cancel(host, req->a_args.block, fl) == 0) |
|
goto out_unblock; |
|
} |
|
|
|
if (resp->status == nlm_granted) { |
|
down_read(&host->h_rwsem); |
|
/* Check whether or not the server has rebooted */ |
|
if (fl->fl_u.nfs_fl.state != host->h_state) { |
|
up_read(&host->h_rwsem); |
|
goto again; |
|
} |
|
/* Ensure the resulting lock will get added to granted list */ |
|
fl->fl_flags |= FL_SLEEP; |
|
if (do_vfs_lock(fl) < 0) |
|
printk(KERN_WARNING "%s: VFS is out of sync with lock manager!\n", __func__); |
|
up_read(&host->h_rwsem); |
|
fl->fl_flags = fl_flags; |
|
status = 0; |
|
} |
|
if (status < 0) |
|
goto out_unlock; |
|
/* |
|
* EAGAIN doesn't make sense for sleeping locks, and in some |
|
* cases NLM_LCK_DENIED is returned for a permanent error. So |
|
* turn it into an ENOLCK. |
|
*/ |
|
if (resp->status == nlm_lck_denied && (fl_flags & FL_SLEEP)) |
|
status = -ENOLCK; |
|
else |
|
status = nlm_stat_to_errno(resp->status); |
|
out_unblock: |
|
nlmclnt_finish_block(block); |
|
out: |
|
nlmclnt_release_call(req); |
|
return status; |
|
out_unlock: |
|
/* Fatal error: ensure that we remove the lock altogether */ |
|
dprintk("lockd: lock attempt ended in fatal error.\n" |
|
" Attempting to unlock.\n"); |
|
nlmclnt_finish_block(block); |
|
fl_type = fl->fl_type; |
|
fl->fl_type = F_UNLCK; |
|
down_read(&host->h_rwsem); |
|
do_vfs_lock(fl); |
|
up_read(&host->h_rwsem); |
|
fl->fl_type = fl_type; |
|
fl->fl_flags = fl_flags; |
|
nlmclnt_async_call(cred, req, NLMPROC_UNLOCK, &nlmclnt_unlock_ops); |
|
return status; |
|
} |
|
|
|
/* |
|
* RECLAIM: Try to reclaim a lock |
|
*/ |
|
int |
|
nlmclnt_reclaim(struct nlm_host *host, struct file_lock *fl, |
|
struct nlm_rqst *req) |
|
{ |
|
int status; |
|
|
|
memset(req, 0, sizeof(*req)); |
|
locks_init_lock(&req->a_args.lock.fl); |
|
locks_init_lock(&req->a_res.lock.fl); |
|
req->a_host = host; |
|
|
|
/* Set up the argument struct */ |
|
nlmclnt_setlockargs(req, fl); |
|
req->a_args.reclaim = 1; |
|
|
|
status = nlmclnt_call(nfs_file_cred(fl->fl_file), req, NLMPROC_LOCK); |
|
if (status >= 0 && req->a_res.status == nlm_granted) |
|
return 0; |
|
|
|
printk(KERN_WARNING "lockd: failed to reclaim lock for pid %d " |
|
"(errno %d, status %d)\n", fl->fl_pid, |
|
status, ntohl(req->a_res.status)); |
|
|
|
/* |
|
* FIXME: This is a serious failure. We can |
|
* |
|
* a. Ignore the problem |
|
* b. Send the owning process some signal (Linux doesn't have |
|
* SIGLOST, though...) |
|
* c. Retry the operation |
|
* |
|
* Until someone comes up with a simple implementation |
|
* for b or c, I'll choose option a. |
|
*/ |
|
|
|
return -ENOLCK; |
|
} |
|
|
|
/* |
|
* UNLOCK: remove an existing lock |
|
*/ |
|
static int |
|
nlmclnt_unlock(struct nlm_rqst *req, struct file_lock *fl) |
|
{ |
|
struct nlm_host *host = req->a_host; |
|
struct nlm_res *resp = &req->a_res; |
|
int status; |
|
unsigned char fl_flags = fl->fl_flags; |
|
|
|
/* |
|
* Note: the server is supposed to either grant us the unlock |
|
* request, or to deny it with NLM_LCK_DENIED_GRACE_PERIOD. In either |
|
* case, we want to unlock. |
|
*/ |
|
fl->fl_flags |= FL_EXISTS; |
|
down_read(&host->h_rwsem); |
|
status = do_vfs_lock(fl); |
|
up_read(&host->h_rwsem); |
|
fl->fl_flags = fl_flags; |
|
if (status == -ENOENT) { |
|
status = 0; |
|
goto out; |
|
} |
|
|
|
refcount_inc(&req->a_count); |
|
status = nlmclnt_async_call(nfs_file_cred(fl->fl_file), req, |
|
NLMPROC_UNLOCK, &nlmclnt_unlock_ops); |
|
if (status < 0) |
|
goto out; |
|
|
|
if (resp->status == nlm_granted) |
|
goto out; |
|
|
|
if (resp->status != nlm_lck_denied_nolocks) |
|
printk("lockd: unexpected unlock status: %d\n", |
|
ntohl(resp->status)); |
|
/* What to do now? I'm out of my depth... */ |
|
status = -ENOLCK; |
|
out: |
|
nlmclnt_release_call(req); |
|
return status; |
|
} |
|
|
|
static void nlmclnt_unlock_prepare(struct rpc_task *task, void *data) |
|
{ |
|
struct nlm_rqst *req = data; |
|
const struct nlmclnt_operations *nlmclnt_ops = req->a_host->h_nlmclnt_ops; |
|
bool defer_call = false; |
|
|
|
if (nlmclnt_ops && nlmclnt_ops->nlmclnt_unlock_prepare) |
|
defer_call = nlmclnt_ops->nlmclnt_unlock_prepare(task, req->a_callback_data); |
|
|
|
if (!defer_call) |
|
rpc_call_start(task); |
|
} |
|
|
|
static void nlmclnt_unlock_callback(struct rpc_task *task, void *data) |
|
{ |
|
struct nlm_rqst *req = data; |
|
u32 status = ntohl(req->a_res.status); |
|
|
|
if (RPC_SIGNALLED(task)) |
|
goto die; |
|
|
|
if (task->tk_status < 0) { |
|
dprintk("lockd: unlock failed (err = %d)\n", -task->tk_status); |
|
switch (task->tk_status) { |
|
case -EACCES: |
|
case -EIO: |
|
goto die; |
|
default: |
|
goto retry_rebind; |
|
} |
|
} |
|
if (status == NLM_LCK_DENIED_GRACE_PERIOD) { |
|
rpc_delay(task, NLMCLNT_GRACE_WAIT); |
|
goto retry_unlock; |
|
} |
|
if (status != NLM_LCK_GRANTED) |
|
printk(KERN_WARNING "lockd: unexpected unlock status: %d\n", status); |
|
die: |
|
return; |
|
retry_rebind: |
|
nlm_rebind_host(req->a_host); |
|
retry_unlock: |
|
rpc_restart_call(task); |
|
} |
|
|
|
static const struct rpc_call_ops nlmclnt_unlock_ops = { |
|
.rpc_call_prepare = nlmclnt_unlock_prepare, |
|
.rpc_call_done = nlmclnt_unlock_callback, |
|
.rpc_release = nlmclnt_rpc_release, |
|
}; |
|
|
|
/* |
|
* Cancel a blocked lock request. |
|
* We always use an async RPC call for this in order not to hang a |
|
* process that has been Ctrl-C'ed. |
|
*/ |
|
static int nlmclnt_cancel(struct nlm_host *host, int block, struct file_lock *fl) |
|
{ |
|
struct nlm_rqst *req; |
|
int status; |
|
|
|
dprintk("lockd: blocking lock attempt was interrupted by a signal.\n" |
|
" Attempting to cancel lock.\n"); |
|
|
|
req = nlm_alloc_call(host); |
|
if (!req) |
|
return -ENOMEM; |
|
req->a_flags = RPC_TASK_ASYNC; |
|
|
|
nlmclnt_setlockargs(req, fl); |
|
req->a_args.block = block; |
|
|
|
refcount_inc(&req->a_count); |
|
status = nlmclnt_async_call(nfs_file_cred(fl->fl_file), req, |
|
NLMPROC_CANCEL, &nlmclnt_cancel_ops); |
|
if (status == 0 && req->a_res.status == nlm_lck_denied) |
|
status = -ENOLCK; |
|
nlmclnt_release_call(req); |
|
return status; |
|
} |
|
|
|
static void nlmclnt_cancel_callback(struct rpc_task *task, void *data) |
|
{ |
|
struct nlm_rqst *req = data; |
|
u32 status = ntohl(req->a_res.status); |
|
|
|
if (RPC_SIGNALLED(task)) |
|
goto die; |
|
|
|
if (task->tk_status < 0) { |
|
dprintk("lockd: CANCEL call error %d, retrying.\n", |
|
task->tk_status); |
|
goto retry_cancel; |
|
} |
|
|
|
dprintk("lockd: cancel status %u (task %u)\n", |
|
status, task->tk_pid); |
|
|
|
switch (status) { |
|
case NLM_LCK_GRANTED: |
|
case NLM_LCK_DENIED_GRACE_PERIOD: |
|
case NLM_LCK_DENIED: |
|
/* Everything's good */ |
|
break; |
|
case NLM_LCK_DENIED_NOLOCKS: |
|
dprintk("lockd: CANCEL failed (server has no locks)\n"); |
|
goto retry_cancel; |
|
default: |
|
printk(KERN_NOTICE "lockd: weird return %d for CANCEL call\n", |
|
status); |
|
} |
|
|
|
die: |
|
return; |
|
|
|
retry_cancel: |
|
/* Don't ever retry more than 3 times */ |
|
if (req->a_retries++ >= NLMCLNT_MAX_RETRIES) |
|
goto die; |
|
nlm_rebind_host(req->a_host); |
|
rpc_restart_call(task); |
|
rpc_delay(task, 30 * HZ); |
|
} |
|
|
|
static const struct rpc_call_ops nlmclnt_cancel_ops = { |
|
.rpc_call_done = nlmclnt_cancel_callback, |
|
.rpc_release = nlmclnt_rpc_release, |
|
}; |
|
|
|
/* |
|
* Convert an NLM status code to a generic kernel errno |
|
*/ |
|
static int |
|
nlm_stat_to_errno(__be32 status) |
|
{ |
|
switch(ntohl(status)) { |
|
case NLM_LCK_GRANTED: |
|
return 0; |
|
case NLM_LCK_DENIED: |
|
return -EAGAIN; |
|
case NLM_LCK_DENIED_NOLOCKS: |
|
case NLM_LCK_DENIED_GRACE_PERIOD: |
|
return -ENOLCK; |
|
case NLM_LCK_BLOCKED: |
|
printk(KERN_NOTICE "lockd: unexpected status NLM_BLOCKED\n"); |
|
return -ENOLCK; |
|
#ifdef CONFIG_LOCKD_V4 |
|
case NLM_DEADLCK: |
|
return -EDEADLK; |
|
case NLM_ROFS: |
|
return -EROFS; |
|
case NLM_STALE_FH: |
|
return -ESTALE; |
|
case NLM_FBIG: |
|
return -EOVERFLOW; |
|
case NLM_FAILED: |
|
return -ENOLCK; |
|
#endif |
|
} |
|
printk(KERN_NOTICE "lockd: unexpected server status %d\n", |
|
ntohl(status)); |
|
return -ENOLCK; |
|
}
|
|
|