// SPDX-License-Identifier: GPL-2.0-or-later
|
/* AFS file locking support
|
*
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* Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
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* Written by David Howells (dhowells@redhat.com)
|
*/
|
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#include "internal.h"
|
|
#define AFS_LOCK_GRANTED 0
|
#define AFS_LOCK_PENDING 1
|
#define AFS_LOCK_YOUR_TRY 2
|
|
struct workqueue_struct *afs_lock_manager;
|
|
static void afs_next_locker(struct afs_vnode *vnode, int error);
|
static void afs_fl_copy_lock(struct file_lock *new, struct file_lock *fl);
|
static void afs_fl_release_private(struct file_lock *fl);
|
|
static const struct file_lock_operations afs_lock_ops = {
|
.fl_copy_lock = afs_fl_copy_lock,
|
.fl_release_private = afs_fl_release_private,
|
};
|
|
static inline void afs_set_lock_state(struct afs_vnode *vnode, enum afs_lock_state state)
|
{
|
_debug("STATE %u -> %u", vnode->lock_state, state);
|
vnode->lock_state = state;
|
}
|
|
static atomic_t afs_file_lock_debug_id;
|
|
/*
|
* if the callback is broken on this vnode, then the lock may now be available
|
*/
|
void afs_lock_may_be_available(struct afs_vnode *vnode)
|
{
|
_enter("{%llx:%llu}", vnode->fid.vid, vnode->fid.vnode);
|
|
spin_lock(&vnode->lock);
|
if (vnode->lock_state == AFS_VNODE_LOCK_WAITING_FOR_CB)
|
afs_next_locker(vnode, 0);
|
trace_afs_flock_ev(vnode, NULL, afs_flock_callback_break, 0);
|
spin_unlock(&vnode->lock);
|
}
|
|
/*
|
* the lock will time out in 5 minutes unless we extend it, so schedule
|
* extension in a bit less than that time
|
*/
|
static void afs_schedule_lock_extension(struct afs_vnode *vnode)
|
{
|
ktime_t expires_at, now, duration;
|
u64 duration_j;
|
|
expires_at = ktime_add_ms(vnode->locked_at, AFS_LOCKWAIT * 1000 / 2);
|
now = ktime_get_real();
|
duration = ktime_sub(expires_at, now);
|
if (duration <= 0)
|
duration_j = 0;
|
else
|
duration_j = nsecs_to_jiffies(ktime_to_ns(duration));
|
|
queue_delayed_work(afs_lock_manager, &vnode->lock_work, duration_j);
|
}
|
|
/*
|
* In the case of successful completion of a lock operation, record the time
|
* the reply appeared and start the lock extension timer.
|
*/
|
void afs_lock_op_done(struct afs_call *call)
|
{
|
struct afs_operation *op = call->op;
|
struct afs_vnode *vnode = op->file[0].vnode;
|
|
if (call->error == 0) {
|
spin_lock(&vnode->lock);
|
trace_afs_flock_ev(vnode, NULL, afs_flock_timestamp, 0);
|
vnode->locked_at = call->issue_time;
|
afs_schedule_lock_extension(vnode);
|
spin_unlock(&vnode->lock);
|
}
|
}
|
|
/*
|
* grant one or more locks (readlocks are allowed to jump the queue if the
|
* first lock in the queue is itself a readlock)
|
* - the caller must hold the vnode lock
|
*/
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static void afs_grant_locks(struct afs_vnode *vnode)
|
{
|
struct file_lock *p, *_p;
|
bool exclusive = (vnode->lock_type == AFS_LOCK_WRITE);
|
|
list_for_each_entry_safe(p, _p, &vnode->pending_locks, fl_u.afs.link) {
|
if (!exclusive && p->fl_type == F_WRLCK)
|
continue;
|
|
list_move_tail(&p->fl_u.afs.link, &vnode->granted_locks);
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p->fl_u.afs.state = AFS_LOCK_GRANTED;
|
trace_afs_flock_op(vnode, p, afs_flock_op_grant);
|
wake_up(&p->fl_wait);
|
}
|
}
|
|
/*
|
* If an error is specified, reject every pending lock that matches the
|
* authentication and type of the lock we failed to get. If there are any
|
* remaining lockers, try to wake up one of them to have a go.
|
*/
|
static void afs_next_locker(struct afs_vnode *vnode, int error)
|
{
|
struct file_lock *p, *_p, *next = NULL;
|
struct key *key = vnode->lock_key;
|
unsigned int fl_type = F_RDLCK;
|
|
_enter("");
|
|
if (vnode->lock_type == AFS_LOCK_WRITE)
|
fl_type = F_WRLCK;
|
|
list_for_each_entry_safe(p, _p, &vnode->pending_locks, fl_u.afs.link) {
|
if (error &&
|
p->fl_type == fl_type &&
|
afs_file_key(p->fl_file) == key) {
|
list_del_init(&p->fl_u.afs.link);
|
p->fl_u.afs.state = error;
|
wake_up(&p->fl_wait);
|
}
|
|
/* Select the next locker to hand off to. */
|
if (next &&
|
(next->fl_type == F_WRLCK || p->fl_type == F_RDLCK))
|
continue;
|
next = p;
|
}
|
|
vnode->lock_key = NULL;
|
key_put(key);
|
|
if (next) {
|
afs_set_lock_state(vnode, AFS_VNODE_LOCK_SETTING);
|
next->fl_u.afs.state = AFS_LOCK_YOUR_TRY;
|
trace_afs_flock_op(vnode, next, afs_flock_op_wake);
|
wake_up(&next->fl_wait);
|
} else {
|
afs_set_lock_state(vnode, AFS_VNODE_LOCK_NONE);
|
trace_afs_flock_ev(vnode, NULL, afs_flock_no_lockers, 0);
|
}
|
|
_leave("");
|
}
|
|
/*
|
* Kill off all waiters in the the pending lock queue due to the vnode being
|
* deleted.
|
*/
|
static void afs_kill_lockers_enoent(struct afs_vnode *vnode)
|
{
|
struct file_lock *p;
|
|
afs_set_lock_state(vnode, AFS_VNODE_LOCK_DELETED);
|
|
while (!list_empty(&vnode->pending_locks)) {
|
p = list_entry(vnode->pending_locks.next,
|
struct file_lock, fl_u.afs.link);
|
list_del_init(&p->fl_u.afs.link);
|
p->fl_u.afs.state = -ENOENT;
|
wake_up(&p->fl_wait);
|
}
|
|
key_put(vnode->lock_key);
|
vnode->lock_key = NULL;
|
}
|
|
static void afs_lock_success(struct afs_operation *op)
|
{
|
_enter("op=%08x", op->debug_id);
|
afs_vnode_commit_status(op, &op->file[0]);
|
}
|
|
static const struct afs_operation_ops afs_set_lock_operation = {
|
.issue_afs_rpc = afs_fs_set_lock,
|
.issue_yfs_rpc = yfs_fs_set_lock,
|
.success = afs_lock_success,
|
.aborted = afs_check_for_remote_deletion,
|
};
|
|
/*
|
* Get a lock on a file
|
*/
|
static int afs_set_lock(struct afs_vnode *vnode, struct key *key,
|
afs_lock_type_t type)
|
{
|
struct afs_operation *op;
|
|
_enter("%s{%llx:%llu.%u},%x,%u",
|
vnode->volume->name,
|
vnode->fid.vid,
|
vnode->fid.vnode,
|
vnode->fid.unique,
|
key_serial(key), type);
|
|
op = afs_alloc_operation(key, vnode->volume);
|
if (IS_ERR(op))
|
return PTR_ERR(op);
|
|
afs_op_set_vnode(op, 0, vnode);
|
|
op->lock.type = type;
|
op->ops = &afs_set_lock_operation;
|
return afs_do_sync_operation(op);
|
}
|
|
static const struct afs_operation_ops afs_extend_lock_operation = {
|
.issue_afs_rpc = afs_fs_extend_lock,
|
.issue_yfs_rpc = yfs_fs_extend_lock,
|
.success = afs_lock_success,
|
};
|
|
/*
|
* Extend a lock on a file
|
*/
|
static int afs_extend_lock(struct afs_vnode *vnode, struct key *key)
|
{
|
struct afs_operation *op;
|
|
_enter("%s{%llx:%llu.%u},%x",
|
vnode->volume->name,
|
vnode->fid.vid,
|
vnode->fid.vnode,
|
vnode->fid.unique,
|
key_serial(key));
|
|
op = afs_alloc_operation(key, vnode->volume);
|
if (IS_ERR(op))
|
return PTR_ERR(op);
|
|
afs_op_set_vnode(op, 0, vnode);
|
|
op->flags |= AFS_OPERATION_UNINTR;
|
op->ops = &afs_extend_lock_operation;
|
return afs_do_sync_operation(op);
|
}
|
|
static const struct afs_operation_ops afs_release_lock_operation = {
|
.issue_afs_rpc = afs_fs_release_lock,
|
.issue_yfs_rpc = yfs_fs_release_lock,
|
.success = afs_lock_success,
|
};
|
|
/*
|
* Release a lock on a file
|
*/
|
static int afs_release_lock(struct afs_vnode *vnode, struct key *key)
|
{
|
struct afs_operation *op;
|
|
_enter("%s{%llx:%llu.%u},%x",
|
vnode->volume->name,
|
vnode->fid.vid,
|
vnode->fid.vnode,
|
vnode->fid.unique,
|
key_serial(key));
|
|
op = afs_alloc_operation(key, vnode->volume);
|
if (IS_ERR(op))
|
return PTR_ERR(op);
|
|
afs_op_set_vnode(op, 0, vnode);
|
|
op->flags |= AFS_OPERATION_UNINTR;
|
op->ops = &afs_release_lock_operation;
|
return afs_do_sync_operation(op);
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}
|
|
/*
|
* do work for a lock, including:
|
* - probing for a lock we're waiting on but didn't get immediately
|
* - extending a lock that's close to timing out
|
*/
|
void afs_lock_work(struct work_struct *work)
|
{
|
struct afs_vnode *vnode =
|
container_of(work, struct afs_vnode, lock_work.work);
|
struct key *key;
|
int ret;
|
|
_enter("{%llx:%llu}", vnode->fid.vid, vnode->fid.vnode);
|
|
spin_lock(&vnode->lock);
|
|
again:
|
_debug("wstate %u for %p", vnode->lock_state, vnode);
|
switch (vnode->lock_state) {
|
case AFS_VNODE_LOCK_NEED_UNLOCK:
|
afs_set_lock_state(vnode, AFS_VNODE_LOCK_UNLOCKING);
|
trace_afs_flock_ev(vnode, NULL, afs_flock_work_unlocking, 0);
|
spin_unlock(&vnode->lock);
|
|
/* attempt to release the server lock; if it fails, we just
|
* wait 5 minutes and it'll expire anyway */
|
ret = afs_release_lock(vnode, vnode->lock_key);
|
if (ret < 0 && vnode->lock_state != AFS_VNODE_LOCK_DELETED) {
|
trace_afs_flock_ev(vnode, NULL, afs_flock_release_fail,
|
ret);
|
printk(KERN_WARNING "AFS:"
|
" Failed to release lock on {%llx:%llx} error %d\n",
|
vnode->fid.vid, vnode->fid.vnode, ret);
|
}
|
|
spin_lock(&vnode->lock);
|
if (ret == -ENOENT)
|
afs_kill_lockers_enoent(vnode);
|
else
|
afs_next_locker(vnode, 0);
|
spin_unlock(&vnode->lock);
|
return;
|
|
/* If we've already got a lock, then it must be time to extend that
|
* lock as AFS locks time out after 5 minutes.
|
*/
|
case AFS_VNODE_LOCK_GRANTED:
|
_debug("extend");
|
|
ASSERT(!list_empty(&vnode->granted_locks));
|
|
key = key_get(vnode->lock_key);
|
afs_set_lock_state(vnode, AFS_VNODE_LOCK_EXTENDING);
|
trace_afs_flock_ev(vnode, NULL, afs_flock_work_extending, 0);
|
spin_unlock(&vnode->lock);
|
|
ret = afs_extend_lock(vnode, key); /* RPC */
|
key_put(key);
|
|
if (ret < 0) {
|
trace_afs_flock_ev(vnode, NULL, afs_flock_extend_fail,
|
ret);
|
pr_warn("AFS: Failed to extend lock on {%llx:%llx} error %d\n",
|
vnode->fid.vid, vnode->fid.vnode, ret);
|
}
|
|
spin_lock(&vnode->lock);
|
|
if (ret == -ENOENT) {
|
afs_kill_lockers_enoent(vnode);
|
spin_unlock(&vnode->lock);
|
return;
|
}
|
|
if (vnode->lock_state != AFS_VNODE_LOCK_EXTENDING)
|
goto again;
|
afs_set_lock_state(vnode, AFS_VNODE_LOCK_GRANTED);
|
|
if (ret != 0)
|
queue_delayed_work(afs_lock_manager, &vnode->lock_work,
|
HZ * 10);
|
spin_unlock(&vnode->lock);
|
_leave(" [ext]");
|
return;
|
|
/* If we're waiting for a callback to indicate lock release, we can't
|
* actually rely on this, so need to recheck at regular intervals. The
|
* problem is that the server might not notify us if the lock just
|
* expires (say because a client died) rather than being explicitly
|
* released.
|
*/
|
case AFS_VNODE_LOCK_WAITING_FOR_CB:
|
_debug("retry");
|
afs_next_locker(vnode, 0);
|
spin_unlock(&vnode->lock);
|
return;
|
|
case AFS_VNODE_LOCK_DELETED:
|
afs_kill_lockers_enoent(vnode);
|
spin_unlock(&vnode->lock);
|
return;
|
|
default:
|
/* Looks like a lock request was withdrawn. */
|
spin_unlock(&vnode->lock);
|
_leave(" [no]");
|
return;
|
}
|
}
|
|
/*
|
* pass responsibility for the unlocking of a vnode on the server to the
|
* manager thread, lest a pending signal in the calling thread interrupt
|
* AF_RXRPC
|
* - the caller must hold the vnode lock
|
*/
|
static void afs_defer_unlock(struct afs_vnode *vnode)
|
{
|
_enter("%u", vnode->lock_state);
|
|
if (list_empty(&vnode->granted_locks) &&
|
(vnode->lock_state == AFS_VNODE_LOCK_GRANTED ||
|
vnode->lock_state == AFS_VNODE_LOCK_EXTENDING)) {
|
cancel_delayed_work(&vnode->lock_work);
|
|
afs_set_lock_state(vnode, AFS_VNODE_LOCK_NEED_UNLOCK);
|
trace_afs_flock_ev(vnode, NULL, afs_flock_defer_unlock, 0);
|
queue_delayed_work(afs_lock_manager, &vnode->lock_work, 0);
|
}
|
}
|
|
/*
|
* Check that our view of the file metadata is up to date and check to see
|
* whether we think that we have a locking permit.
|
*/
|
static int afs_do_setlk_check(struct afs_vnode *vnode, struct key *key,
|
enum afs_flock_mode mode, afs_lock_type_t type)
|
{
|
afs_access_t access;
|
int ret;
|
|
/* Make sure we've got a callback on this file and that our view of the
|
* data version is up to date.
|
*/
|
ret = afs_validate(vnode, key);
|
if (ret < 0)
|
return ret;
|
|
/* Check the permission set to see if we're actually going to be
|
* allowed to get a lock on this file.
|
*/
|
ret = afs_check_permit(vnode, key, &access);
|
if (ret < 0)
|
return ret;
|
|
/* At a rough estimation, you need LOCK, WRITE or INSERT perm to
|
* read-lock a file and WRITE or INSERT perm to write-lock a file.
|
*
|
* We can't rely on the server to do this for us since if we want to
|
* share a read lock that we already have, we won't go the server.
|
*/
|
if (type == AFS_LOCK_READ) {
|
if (!(access & (AFS_ACE_INSERT | AFS_ACE_WRITE | AFS_ACE_LOCK)))
|
return -EACCES;
|
} else {
|
if (!(access & (AFS_ACE_INSERT | AFS_ACE_WRITE)))
|
return -EACCES;
|
}
|
|
return 0;
|
}
|
|
/*
|
* request a lock on a file on the server
|
*/
|
static int afs_do_setlk(struct file *file, struct file_lock *fl)
|
{
|
struct inode *inode = locks_inode(file);
|
struct afs_vnode *vnode = AFS_FS_I(inode);
|
enum afs_flock_mode mode = AFS_FS_S(inode->i_sb)->flock_mode;
|
afs_lock_type_t type;
|
struct key *key = afs_file_key(file);
|
bool partial, no_server_lock = false;
|
int ret;
|
|
if (mode == afs_flock_mode_unset)
|
mode = afs_flock_mode_openafs;
|
|
_enter("{%llx:%llu},%llu-%llu,%u,%u",
|
vnode->fid.vid, vnode->fid.vnode,
|
fl->fl_start, fl->fl_end, fl->fl_type, mode);
|
|
fl->fl_ops = &afs_lock_ops;
|
INIT_LIST_HEAD(&fl->fl_u.afs.link);
|
fl->fl_u.afs.state = AFS_LOCK_PENDING;
|
|
partial = (fl->fl_start != 0 || fl->fl_end != OFFSET_MAX);
|
type = (fl->fl_type == F_RDLCK) ? AFS_LOCK_READ : AFS_LOCK_WRITE;
|
if (mode == afs_flock_mode_write && partial)
|
type = AFS_LOCK_WRITE;
|
|
ret = afs_do_setlk_check(vnode, key, mode, type);
|
if (ret < 0)
|
return ret;
|
|
trace_afs_flock_op(vnode, fl, afs_flock_op_set_lock);
|
|
/* AFS3 protocol only supports full-file locks and doesn't provide any
|
* method of upgrade/downgrade, so we need to emulate for partial-file
|
* locks.
|
*
|
* The OpenAFS client only gets a server lock for a full-file lock and
|
* keeps partial-file locks local. Allow this behaviour to be emulated
|
* (as the default).
|
*/
|
if (mode == afs_flock_mode_local ||
|
(partial && mode == afs_flock_mode_openafs)) {
|
no_server_lock = true;
|
goto skip_server_lock;
|
}
|
|
spin_lock(&vnode->lock);
|
list_add_tail(&fl->fl_u.afs.link, &vnode->pending_locks);
|
|
ret = -ENOENT;
|
if (vnode->lock_state == AFS_VNODE_LOCK_DELETED)
|
goto error_unlock;
|
|
/* If we've already got a lock on the server then try to move to having
|
* the VFS grant the requested lock. Note that this means that other
|
* clients may get starved out.
|
*/
|
_debug("try %u", vnode->lock_state);
|
if (vnode->lock_state == AFS_VNODE_LOCK_GRANTED) {
|
if (type == AFS_LOCK_READ) {
|
_debug("instant readlock");
|
list_move_tail(&fl->fl_u.afs.link, &vnode->granted_locks);
|
fl->fl_u.afs.state = AFS_LOCK_GRANTED;
|
goto vnode_is_locked_u;
|
}
|
|
if (vnode->lock_type == AFS_LOCK_WRITE) {
|
_debug("instant writelock");
|
list_move_tail(&fl->fl_u.afs.link, &vnode->granted_locks);
|
fl->fl_u.afs.state = AFS_LOCK_GRANTED;
|
goto vnode_is_locked_u;
|
}
|
}
|
|
if (vnode->lock_state == AFS_VNODE_LOCK_NONE &&
|
!(fl->fl_flags & FL_SLEEP)) {
|
ret = -EAGAIN;
|
if (type == AFS_LOCK_READ) {
|
if (vnode->status.lock_count == -1)
|
goto lock_is_contended; /* Write locked */
|
} else {
|
if (vnode->status.lock_count != 0)
|
goto lock_is_contended; /* Locked */
|
}
|
}
|
|
if (vnode->lock_state != AFS_VNODE_LOCK_NONE)
|
goto need_to_wait;
|
|
try_to_lock:
|
/* We don't have a lock on this vnode and we aren't currently waiting
|
* for one either, so ask the server for a lock.
|
*
|
* Note that we need to be careful if we get interrupted by a signal
|
* after dispatching the request as we may still get the lock, even
|
* though we don't wait for the reply (it's not too bad a problem - the
|
* lock will expire in 5 mins anyway).
|
*/
|
trace_afs_flock_ev(vnode, fl, afs_flock_try_to_lock, 0);
|
vnode->lock_key = key_get(key);
|
vnode->lock_type = type;
|
afs_set_lock_state(vnode, AFS_VNODE_LOCK_SETTING);
|
spin_unlock(&vnode->lock);
|
|
ret = afs_set_lock(vnode, key, type); /* RPC */
|
|
spin_lock(&vnode->lock);
|
switch (ret) {
|
case -EKEYREJECTED:
|
case -EKEYEXPIRED:
|
case -EKEYREVOKED:
|
case -EPERM:
|
case -EACCES:
|
fl->fl_u.afs.state = ret;
|
trace_afs_flock_ev(vnode, fl, afs_flock_fail_perm, ret);
|
list_del_init(&fl->fl_u.afs.link);
|
afs_next_locker(vnode, ret);
|
goto error_unlock;
|
|
case -ENOENT:
|
fl->fl_u.afs.state = ret;
|
trace_afs_flock_ev(vnode, fl, afs_flock_fail_other, ret);
|
list_del_init(&fl->fl_u.afs.link);
|
afs_kill_lockers_enoent(vnode);
|
goto error_unlock;
|
|
default:
|
fl->fl_u.afs.state = ret;
|
trace_afs_flock_ev(vnode, fl, afs_flock_fail_other, ret);
|
list_del_init(&fl->fl_u.afs.link);
|
afs_next_locker(vnode, 0);
|
goto error_unlock;
|
|
case -EWOULDBLOCK:
|
/* The server doesn't have a lock-waiting queue, so the client
|
* will have to retry. The server will break the outstanding
|
* callbacks on a file when a lock is released.
|
*/
|
ASSERT(list_empty(&vnode->granted_locks));
|
ASSERTCMP(vnode->pending_locks.next, ==, &fl->fl_u.afs.link);
|
goto lock_is_contended;
|
|
case 0:
|
afs_set_lock_state(vnode, AFS_VNODE_LOCK_GRANTED);
|
trace_afs_flock_ev(vnode, fl, afs_flock_acquired, type);
|
afs_grant_locks(vnode);
|
goto vnode_is_locked_u;
|
}
|
|
vnode_is_locked_u:
|
spin_unlock(&vnode->lock);
|
vnode_is_locked:
|
/* the lock has been granted by the server... */
|
ASSERTCMP(fl->fl_u.afs.state, ==, AFS_LOCK_GRANTED);
|
|
skip_server_lock:
|
/* ... but the VFS still needs to distribute access on this client. */
|
trace_afs_flock_ev(vnode, fl, afs_flock_vfs_locking, 0);
|
ret = locks_lock_file_wait(file, fl);
|
trace_afs_flock_ev(vnode, fl, afs_flock_vfs_lock, ret);
|
if (ret < 0)
|
goto vfs_rejected_lock;
|
|
/* Again, make sure we've got a callback on this file and, again, make
|
* sure that our view of the data version is up to date (we ignore
|
* errors incurred here and deal with the consequences elsewhere).
|
*/
|
afs_validate(vnode, key);
|
_leave(" = 0");
|
return 0;
|
|
lock_is_contended:
|
if (!(fl->fl_flags & FL_SLEEP)) {
|
list_del_init(&fl->fl_u.afs.link);
|
afs_next_locker(vnode, 0);
|
ret = -EAGAIN;
|
goto error_unlock;
|
}
|
|
afs_set_lock_state(vnode, AFS_VNODE_LOCK_WAITING_FOR_CB);
|
trace_afs_flock_ev(vnode, fl, afs_flock_would_block, ret);
|
queue_delayed_work(afs_lock_manager, &vnode->lock_work, HZ * 5);
|
|
need_to_wait:
|
/* We're going to have to wait. Either this client doesn't have a lock
|
* on the server yet and we need to wait for a callback to occur, or
|
* the client does have a lock on the server, but it's shared and we
|
* need an exclusive lock.
|
*/
|
spin_unlock(&vnode->lock);
|
|
trace_afs_flock_ev(vnode, fl, afs_flock_waiting, 0);
|
ret = wait_event_interruptible(fl->fl_wait,
|
fl->fl_u.afs.state != AFS_LOCK_PENDING);
|
trace_afs_flock_ev(vnode, fl, afs_flock_waited, ret);
|
|
if (fl->fl_u.afs.state >= 0 && fl->fl_u.afs.state != AFS_LOCK_GRANTED) {
|
spin_lock(&vnode->lock);
|
|
switch (fl->fl_u.afs.state) {
|
case AFS_LOCK_YOUR_TRY:
|
fl->fl_u.afs.state = AFS_LOCK_PENDING;
|
goto try_to_lock;
|
case AFS_LOCK_PENDING:
|
if (ret > 0) {
|
/* We need to retry the lock. We may not be
|
* notified by the server if it just expired
|
* rather than being released.
|
*/
|
ASSERTCMP(vnode->lock_state, ==, AFS_VNODE_LOCK_WAITING_FOR_CB);
|
afs_set_lock_state(vnode, AFS_VNODE_LOCK_SETTING);
|
fl->fl_u.afs.state = AFS_LOCK_PENDING;
|
goto try_to_lock;
|
}
|
goto error_unlock;
|
case AFS_LOCK_GRANTED:
|
default:
|
break;
|
}
|
|
spin_unlock(&vnode->lock);
|
}
|
|
if (fl->fl_u.afs.state == AFS_LOCK_GRANTED)
|
goto vnode_is_locked;
|
ret = fl->fl_u.afs.state;
|
goto error;
|
|
vfs_rejected_lock:
|
/* The VFS rejected the lock we just obtained, so we have to discard
|
* what we just got. We defer this to the lock manager work item to
|
* deal with.
|
*/
|
_debug("vfs refused %d", ret);
|
if (no_server_lock)
|
goto error;
|
spin_lock(&vnode->lock);
|
list_del_init(&fl->fl_u.afs.link);
|
afs_defer_unlock(vnode);
|
|
error_unlock:
|
spin_unlock(&vnode->lock);
|
error:
|
_leave(" = %d", ret);
|
return ret;
|
}
|
|
/*
|
* unlock on a file on the server
|
*/
|
static int afs_do_unlk(struct file *file, struct file_lock *fl)
|
{
|
struct afs_vnode *vnode = AFS_FS_I(locks_inode(file));
|
int ret;
|
|
_enter("{%llx:%llu},%u", vnode->fid.vid, vnode->fid.vnode, fl->fl_type);
|
|
trace_afs_flock_op(vnode, fl, afs_flock_op_unlock);
|
|
/* Flush all pending writes before doing anything with locks. */
|
vfs_fsync(file, 0);
|
|
ret = locks_lock_file_wait(file, fl);
|
_leave(" = %d [%u]", ret, vnode->lock_state);
|
return ret;
|
}
|
|
/*
|
* return information about a lock we currently hold, if indeed we hold one
|
*/
|
static int afs_do_getlk(struct file *file, struct file_lock *fl)
|
{
|
struct afs_vnode *vnode = AFS_FS_I(locks_inode(file));
|
struct key *key = afs_file_key(file);
|
int ret, lock_count;
|
|
_enter("");
|
|
if (vnode->lock_state == AFS_VNODE_LOCK_DELETED)
|
return -ENOENT;
|
|
fl->fl_type = F_UNLCK;
|
|
/* check local lock records first */
|
posix_test_lock(file, fl);
|
if (fl->fl_type == F_UNLCK) {
|
/* no local locks; consult the server */
|
ret = afs_fetch_status(vnode, key, false, NULL);
|
if (ret < 0)
|
goto error;
|
|
lock_count = READ_ONCE(vnode->status.lock_count);
|
if (lock_count != 0) {
|
if (lock_count > 0)
|
fl->fl_type = F_RDLCK;
|
else
|
fl->fl_type = F_WRLCK;
|
fl->fl_start = 0;
|
fl->fl_end = OFFSET_MAX;
|
fl->fl_pid = 0;
|
}
|
}
|
|
ret = 0;
|
error:
|
_leave(" = %d [%hd]", ret, fl->fl_type);
|
return ret;
|
}
|
|
/*
|
* manage POSIX locks on a file
|
*/
|
int afs_lock(struct file *file, int cmd, struct file_lock *fl)
|
{
|
struct afs_vnode *vnode = AFS_FS_I(locks_inode(file));
|
enum afs_flock_operation op;
|
int ret;
|
|
_enter("{%llx:%llu},%d,{t=%x,fl=%x,r=%Ld:%Ld}",
|
vnode->fid.vid, vnode->fid.vnode, cmd,
|
fl->fl_type, fl->fl_flags,
|
(long long) fl->fl_start, (long long) fl->fl_end);
|
|
/* AFS doesn't support mandatory locks */
|
if (__mandatory_lock(&vnode->vfs_inode) && fl->fl_type != F_UNLCK)
|
return -ENOLCK;
|
|
if (IS_GETLK(cmd))
|
return afs_do_getlk(file, fl);
|
|
fl->fl_u.afs.debug_id = atomic_inc_return(&afs_file_lock_debug_id);
|
trace_afs_flock_op(vnode, fl, afs_flock_op_lock);
|
|
if (fl->fl_type == F_UNLCK)
|
ret = afs_do_unlk(file, fl);
|
else
|
ret = afs_do_setlk(file, fl);
|
|
switch (ret) {
|
case 0: op = afs_flock_op_return_ok; break;
|
case -EAGAIN: op = afs_flock_op_return_eagain; break;
|
case -EDEADLK: op = afs_flock_op_return_edeadlk; break;
|
default: op = afs_flock_op_return_error; break;
|
}
|
trace_afs_flock_op(vnode, fl, op);
|
return ret;
|
}
|
|
/*
|
* manage FLOCK locks on a file
|
*/
|
int afs_flock(struct file *file, int cmd, struct file_lock *fl)
|
{
|
struct afs_vnode *vnode = AFS_FS_I(locks_inode(file));
|
enum afs_flock_operation op;
|
int ret;
|
|
_enter("{%llx:%llu},%d,{t=%x,fl=%x}",
|
vnode->fid.vid, vnode->fid.vnode, cmd,
|
fl->fl_type, fl->fl_flags);
|
|
/*
|
* No BSD flocks over NFS allowed.
|
* Note: we could try to fake a POSIX lock request here by
|
* using ((u32) filp | 0x80000000) or some such as the pid.
|
* Not sure whether that would be unique, though, or whether
|
* that would break in other places.
|
*/
|
if (!(fl->fl_flags & FL_FLOCK))
|
return -ENOLCK;
|
|
fl->fl_u.afs.debug_id = atomic_inc_return(&afs_file_lock_debug_id);
|
trace_afs_flock_op(vnode, fl, afs_flock_op_flock);
|
|
/* we're simulating flock() locks using posix locks on the server */
|
if (fl->fl_type == F_UNLCK)
|
ret = afs_do_unlk(file, fl);
|
else
|
ret = afs_do_setlk(file, fl);
|
|
switch (ret) {
|
case 0: op = afs_flock_op_return_ok; break;
|
case -EAGAIN: op = afs_flock_op_return_eagain; break;
|
case -EDEADLK: op = afs_flock_op_return_edeadlk; break;
|
default: op = afs_flock_op_return_error; break;
|
}
|
trace_afs_flock_op(vnode, fl, op);
|
return ret;
|
}
|
|
/*
|
* the POSIX lock management core VFS code copies the lock record and adds the
|
* copy into its own list, so we need to add that copy to the vnode's lock
|
* queue in the same place as the original (which will be deleted shortly
|
* after)
|
*/
|
static void afs_fl_copy_lock(struct file_lock *new, struct file_lock *fl)
|
{
|
struct afs_vnode *vnode = AFS_FS_I(locks_inode(fl->fl_file));
|
|
_enter("");
|
|
new->fl_u.afs.debug_id = atomic_inc_return(&afs_file_lock_debug_id);
|
|
spin_lock(&vnode->lock);
|
trace_afs_flock_op(vnode, new, afs_flock_op_copy_lock);
|
list_add(&new->fl_u.afs.link, &fl->fl_u.afs.link);
|
spin_unlock(&vnode->lock);
|
}
|
|
/*
|
* need to remove this lock from the vnode queue when it's removed from the
|
* VFS's list
|
*/
|
static void afs_fl_release_private(struct file_lock *fl)
|
{
|
struct afs_vnode *vnode = AFS_FS_I(locks_inode(fl->fl_file));
|
|
_enter("");
|
|
spin_lock(&vnode->lock);
|
|
trace_afs_flock_op(vnode, fl, afs_flock_op_release_lock);
|
list_del_init(&fl->fl_u.afs.link);
|
if (list_empty(&vnode->granted_locks))
|
afs_defer_unlock(vnode);
|
|
_debug("state %u for %p", vnode->lock_state, vnode);
|
spin_unlock(&vnode->lock);
|
}
|
