linux-stable/fs/afs/flock.c
Jeff Layton f7e33bdbd6 fs: remove mandatory file locking support
We added CONFIG_MANDATORY_FILE_LOCKING in 2015, and soon after turned it
off in Fedora and RHEL8. Several other distros have followed suit.

I've heard of one problem in all that time: Someone migrated from an
older distro that supported "-o mand" to one that didn't, and the host
had a fstab entry with "mand" in it which broke on reboot. They didn't
actually _use_ mandatory locking so they just removed the mount option
and moved on.

This patch rips out mandatory locking support wholesale from the kernel,
along with the Kconfig option and the Documentation file. It also
changes the mount code to ignore the "mand" mount option instead of
erroring out, and to throw a big, ugly warning.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
2021-08-23 06:15:36 -04:00

877 lines
24 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/* AFS file locking support
*
* Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*/
#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->reply_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
*/
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);
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);
}
/*
* 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);
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);
}