Viewing: ldlm_inodebits.c
// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (c) 2004, 2010, Oracle and/or its affiliates. All rights reserved.
* Use is subject to license terms.
*
* Copyright (c) 2011, 2017, Intel Corporation.
*/
/*
* This file is part of Lustre, http://www.lustre.org/
*
* Author: Peter Braam <braam@clusterfs.com>
* Author: Phil Schwan <phil@clusterfs.com>
*/
/*
* This file contains implementation of IBITS lock type
*
* IBITS lock type contains a bit mask determining various properties of an
* object. The meanings of specific bits are specific to the caller and are
* opaque to LDLM code.
*
* Locks with intersecting bitmasks and conflicting lock modes (e.g. LCK_PW)
* are considered conflicting. See the lock mode compatibility matrix
* in lustre_dlm.h.
*/
#define DEBUG_SUBSYSTEM S_LDLM
#include <lustre_dlm.h>
#include <obd_support.h>
#include <lustre_lib.h>
#include <obd_class.h>
#include "ldlm_internal.h"
#ifdef CONFIG_LUSTRE_FS_SERVER
/**
* It should iterate through all waiting locks on a given resource queue and
* attempt to grant them. An optimization is to check only heads waitintg
* locks for each inodebit type.
*
* Must be called with resource lock held.
*/
int ldlm_reprocess_inodebits_queue(struct ldlm_resource *res,
struct list_head *queue,
struct list_head *work_list,
enum ldlm_process_intention intention,
enum mds_ibits_locks mask)
{
__u64 flags;
int rc = LDLM_ITER_CONTINUE;
enum ldlm_error err;
LIST_HEAD(bl_ast_list);
struct ldlm_ibits_queues *queues = res->lr_ibits_queues;
int i;
ENTRY;
check_res_locked(res);
LASSERT(res->lr_type == LDLM_IBITS);
LASSERT(intention == LDLM_PROCESS_RESCAN ||
intention == LDLM_PROCESS_RECOVERY);
if (intention == LDLM_PROCESS_RECOVERY)
return ldlm_reprocess_queue(res, queue, work_list, intention,
0);
restart:
CDEBUG(D_DLMTRACE, "--- Reprocess resource "DLDLMRES" (%p)\n",
PLDLMRES(res), res);
if (mask)
CDEBUG(D_DLMTRACE, "Hint %lx\n", mask);
else
mask = MDS_INODELOCK_FULL;
for (i = 0; i < MDS_INODELOCK_NUMBITS; i++) {
LIST_HEAD(rpc_list);
struct list_head *head = &queues->liq_waiting[i];
struct ldlm_lock *pending;
struct ldlm_ibits_node *node;
if (list_empty(head) || !(mask & (1 << i)))
continue;
node = list_first_entry(head, struct ldlm_ibits_node,
lin_link[i]);
pending = node->lock;
LDLM_DEBUG(pending, "Reprocessing lock from queue %d", i);
flags = 0;
rc = ldlm_process_inodebits_lock(pending, &flags, intention,
&err, &rpc_list);
if (ldlm_is_granted(pending)) {
list_splice(&rpc_list, work_list);
mask |= pending->l_policy_data.l_inodebits.bits;
i = ffs(pending->l_policy_data.l_inodebits.bits) - 2;
} else {
list_splice(&rpc_list, &bl_ast_list);
}
}
if (!list_empty(&bl_ast_list)) {
unlock_res(res);
rc = ldlm_run_ast_work(ldlm_res_to_ns(res), &bl_ast_list,
LDLM_WORK_BL_AST);
lock_res(res);
if (rc == -ERESTART) {
mask = MDS_INODELOCK_NONE;
GOTO(restart, rc);
}
}
if (!list_empty(&bl_ast_list))
ldlm_discard_bl_list(&bl_ast_list);
RETURN(rc);
}
/* lock of COS mode is compatible with locks from the same client. */
static inline bool ldlm_cos_same_client(const struct ldlm_lock *req,
const struct ldlm_lock *lock)
{
return lock->l_req_mode == LCK_COS &&
lock->l_client_cookie == req->l_client_cookie;
}
/* lock of TXN mode is compatible with locks from the same MDT. */
static inline bool ldlm_txn_same_server(const struct ldlm_lock *req,
const struct ldlm_lock *lock)
{
return lock->l_req_mode == LCK_TXN &&
lock->l_policy_data.l_inodebits.li_initiator_id ==
req->l_policy_data.l_inodebits.li_initiator_id;
}
/**
* Determine if the lock is compatible with all locks on the queue.
*
* If \a work_list is provided, conflicting locks are linked there.
* If \a work_list is not provided, we exit this function on first conflict.
*
* \retval 0 if there are conflicting locks in the \a queue
* \retval 1 if the lock is compatible to all locks in \a queue
*
* IBITS locks in granted queue are organized in bunches of
* same-mode/same-bits locks called "skip lists". The First lock in the
* bunch contains a pointer to the end of the bunch. This allows us to
* skip an entire bunch when iterating the list in search for conflicting
* locks if first lock of the bunch is not conflicting with us.
*/
static int
ldlm_inodebits_compat_queue(struct list_head *queue, struct ldlm_lock *req,
__u64 *ldlm_flags, struct list_head *work_list)
{
enum ldlm_mode req_mode = req->l_req_mode;
struct list_head *tmp;
struct ldlm_lock *lock;
enum mds_ibits_locks req_bits = req->l_policy_data.l_inodebits.bits;
enum mds_ibits_locks *try_bits =
&req->l_policy_data.l_inodebits.try_bits;
int compat = 1;
ENTRY;
lockmode_verify(req_mode);
/* There is no sense in lock with no bits set. Also such a lock
* would be compatible with any other bit lock.
* Meanwhile that can be true if there were just try_bits and all
* are failed, so just exit gracefully and let the caller to care.
*/
if ((req_bits | *try_bits) == MDS_INODELOCK_NONE)
RETURN(0);
/* Group lock could be only DOM */
if (unlikely(req_mode == LCK_GROUP &&
(req_bits | *try_bits) != MDS_INODELOCK_DOM))
RETURN(-EPROTO);
list_for_each(tmp, queue) {
struct list_head *mode_tail;
lock = list_entry(tmp, struct ldlm_lock, l_res_link);
/* We stop walking the queue if we hit ourselves so we don't
* take conflicting locks enqueued after us into account,
* or we'd wait forever.
*/
if (req == lock)
RETURN(compat);
/* last lock in mode group */
LASSERT(lock->l_sl_mode.prev != NULL);
mode_tail = &list_entry(lock->l_sl_mode.prev, struct ldlm_lock,
l_sl_mode)->l_res_link;
if (lockmode_compat(lock->l_req_mode, req_mode)) {
/* non group locks are compatible, bits don't matter */
if (likely(req_mode != LCK_GROUP)) {
/* jump to last lock in mode group */
tmp = mode_tail;
continue;
}
if (req->l_policy_data.l_inodebits.li_gid ==
lock->l_policy_data.l_inodebits.li_gid) {
if (ldlm_is_granted(lock))
RETURN(2);
if (*ldlm_flags & LDLM_FL_BLOCK_NOWAIT)
RETURN(-EWOULDBLOCK);
/* Place the same group together */
ldlm_resource_insert_lock_after(lock, req);
RETURN(0);
}
} else if (ldlm_cos_same_client(req, lock) ||
ldlm_txn_same_server(req, lock)) {
/* COS/TXN locks need to be checked one by one,
* because client cookie or initiator id may be
* different for locks in mode/policy skiplist.
*/
continue;
}
/* GROUP(by gid) locks placed to a head of the waiting list */
if (unlikely(req_mode == LCK_GROUP && !ldlm_is_granted(lock))) {
compat = 0;
if (lock->l_req_mode != LCK_GROUP) {
/* Already not a GROUP lock, insert before. */
ldlm_resource_insert_lock_before(lock, req);
break;
}
/* Still GROUP but a different gid(the same gid would
* be handled above). Keep searching for the same gid
*/
LASSERT(req->l_policy_data.l_inodebits.li_gid !=
lock->l_policy_data.l_inodebits.li_gid);
continue;
}
for (;;) {
struct list_head *head;
/* Advance loop cursor to last lock in policy group. */
tmp = &list_entry(lock->l_sl_policy.prev,
struct ldlm_lock,
l_sl_policy)->l_res_link;
/* New lock's try_bits are filtered out by ibits
* of all locks in both granted and waiting queues.
*/
*try_bits &= ~(lock->l_policy_data.l_inodebits.bits |
lock->l_policy_data.l_inodebits.try_bits);
if ((req_bits | *try_bits) == MDS_INODELOCK_NONE)
RETURN(0);
/* The new lock ibits is more preferable than try_bits
* of waiting locks so drop conflicting try_bits in
* the waiting queue.
* Notice that try_bits of granted locks must be zero.
*/
lock->l_policy_data.l_inodebits.try_bits &= ~req_bits;
/* Locks with overlapping bits conflict. */
if (lock->l_policy_data.l_inodebits.bits & req_bits) {
compat = 0;
if (unlikely(lock->l_req_mode == LCK_GROUP)) {
LASSERT(ldlm_has_dom(lock));
if (*ldlm_flags & LDLM_FL_BLOCK_NOWAIT)
RETURN(-EWOULDBLOCK);
/* Local combined DOM lock came across
* GROUP DOM lock, it makes the thread
* to be blocked for a long time, not
* allowed, the trybits to be used
* instead.
*/
LASSERT(!(!req->l_export &&
(req_bits & MDS_INODELOCK_DOM) &&
(req_bits & ~MDS_INODELOCK_DOM)));
goto skip_work_list;
}
/* Found a conflicting policy group. */
if (!work_list)
RETURN(0);
/* Add locks of the policy group to @work_list
* as blocking locks for @req
*/
if (lock->l_blocking_ast)
ldlm_add_ast_work_item(lock, req,
work_list);
head = &lock->l_sl_policy;
list_for_each_entry(lock, head, l_sl_policy)
if (lock->l_blocking_ast)
ldlm_add_ast_work_item(lock,
req, work_list);
}
skip_work_list:
if (tmp == mode_tail)
break;
tmp = tmp->next;
lock = list_entry(tmp, struct ldlm_lock, l_res_link);
} /* Loop over policy groups within one mode group. */
} /* Loop over mode groups within @queue. */
RETURN(compat);
}
/**
* Process a granting attempt for IBITS lock.
* Must be called with ns lock held
*
* This function looks for any conflicts for \a lock in the granted or
* waiting queues. The lock is granted if no conflicts are found in
* either queue.
*/
int ldlm_process_inodebits_lock(struct ldlm_lock *lock, __u64 *ldlm_flags,
enum ldlm_process_intention intention,
enum ldlm_error *err,
struct list_head *work_list)
{
struct ldlm_resource *res = lock->l_resource;
struct list_head *grant_work = intention == LDLM_PROCESS_ENQUEUE ?
NULL : work_list;
int rc, rc2 = 0;
ENTRY;
*err = ELDLM_LOCK_ABORTED;
LASSERT(!ldlm_is_granted(lock));
check_res_locked(res);
if (intention == LDLM_PROCESS_RESCAN) {
struct list_head *bl_list =
*ldlm_flags & LDLM_FL_BLOCK_NOWAIT ? NULL : work_list;
LASSERT(lock->l_policy_data.l_inodebits.bits != 0);
/* It is possible that some of granted locks was not canceled
* but converted and is kept in granted queue. So there is
* a window where lock with 'ast_sent' might become granted
* again. Meanwhile a new lock may appear in that window and
* conflicts with the converted lock so the following scenario
* is possible:
*
* 1) lock1 conflicts with lock2
* 2) bl_ast was sent for lock2
* 3) lock3 comes and conflicts with lock2 too
* 4) no bl_ast sent because lock2->l_bl_ast_sent is 1
* 5) lock2 was converted for lock1 but not for lock3
* 6) lock1 granted, lock3 still is waiting for lock2, but
* there will never be another bl_ast for that
*
* To avoid this scenario the work_list is used below to collect
* any blocked locks from granted queue during every reprocess
* and bl_ast will be sent if needed.
*/
*ldlm_flags = 0;
rc = ldlm_inodebits_compat_queue(&res->lr_granted, lock,
ldlm_flags, bl_list);
if (!rc)
RETURN(LDLM_ITER_STOP);
rc = ldlm_inodebits_compat_queue(&res->lr_waiting, lock,
ldlm_flags, NULL);
if (!rc)
RETURN(LDLM_ITER_STOP);
/* grant also try_bits if any */
if (lock->l_policy_data.l_inodebits.try_bits !=
MDS_INODELOCK_NONE) {
lock->l_policy_data.l_inodebits.bits |=
lock->l_policy_data.l_inodebits.try_bits;
lock->l_policy_data.l_inodebits.try_bits =
MDS_INODELOCK_NONE;
*ldlm_flags |= LDLM_FL_LOCK_CHANGED;
}
ldlm_resource_unlink_lock(lock);
ldlm_grant_lock(lock, grant_work);
*err = ELDLM_OK;
RETURN(LDLM_ITER_CONTINUE);
}
rc = ldlm_inodebits_compat_queue(&res->lr_granted, lock,
ldlm_flags, work_list);
if (rc < 0)
GOTO(out, *err = rc);
if (rc != 2) {
rc2 = ldlm_inodebits_compat_queue(&res->lr_waiting, lock,
ldlm_flags, work_list);
if (rc2 < 0)
GOTO(out, *err = rc = rc2);
}
if (rc + rc2 != 2) {
/* if there were only bits to try and all are conflicting */
if ((lock->l_policy_data.l_inodebits.bits |
lock->l_policy_data.l_inodebits.try_bits)) {
/* There is no sense to set LDLM_FL_NO_TIMEOUT to
* @ldlm_flags for DOM lock while they are enqueued
* through intents, i.e. @lock here is local which does
* not timeout.
*/
*err = ELDLM_OK;
}
} else {
/* grant also all remaining try_bits */
if (lock->l_policy_data.l_inodebits.try_bits !=
MDS_INODELOCK_NONE) {
lock->l_policy_data.l_inodebits.bits |=
lock->l_policy_data.l_inodebits.try_bits;
lock->l_policy_data.l_inodebits.try_bits =
MDS_INODELOCK_NONE;
*ldlm_flags |= LDLM_FL_LOCK_CHANGED;
}
LASSERT(lock->l_policy_data.l_inodebits.bits);
ldlm_resource_unlink_lock(lock);
ldlm_grant_lock(lock, grant_work);
*err = ELDLM_OK;
}
RETURN(LDLM_ITER_CONTINUE);
out:
return rc;
}
#endif /* CONFIG_LUSTRE_FS_SERVER */
void ldlm_ibits_policy_wire_to_local(const union ldlm_wire_policy_data *wpolicy,
union ldlm_policy_data *lpolicy)
{
lpolicy->l_inodebits.bits = wpolicy->l_inodebits.bits;
lpolicy->l_inodebits.li_initiator_id =
wpolicy->l_inodebits.li_initiator_id;
/**
* try_bits and li_gid are to be handled outside of generic
* write_to_local due to different behavior on a server and client.
*/
}
void ldlm_ibits_policy_local_to_wire(const union ldlm_policy_data *lpolicy,
union ldlm_wire_policy_data *wpolicy)
{
memset(wpolicy, 0, sizeof(*wpolicy));
wpolicy->l_inodebits.bits = lpolicy->l_inodebits.bits;
wpolicy->l_inodebits.try_bits = lpolicy->l_inodebits.try_bits;
wpolicy->l_inodebits.li_gid = lpolicy->l_inodebits.li_gid;
wpolicy->l_inodebits.li_initiator_id =
lpolicy->l_inodebits.li_initiator_id;
}
/**
* Attempt to convert already granted IBITS lock with several bits set to
* a lock with less bits (downgrade).
*
* Such lock conversion is used to keep lock with non-blocking bits instead of
* cancelling it, introduced for better support of DoM files.
*/
int ldlm_inodebits_drop(struct ldlm_lock *lock, enum mds_ibits_locks to_drop)
{
ENTRY;
check_res_locked(lock->l_resource);
/* Just return if there are no conflicting bits */
if ((lock->l_policy_data.l_inodebits.bits & to_drop) ==
MDS_INODELOCK_NONE) {
LDLM_WARN(lock, "try to drop unset bits %#lx/%#lx",
lock->l_policy_data.l_inodebits.bits, to_drop);
/* nothing to do */
RETURN(0);
}
/* remove lock from a skiplist and put in the new place
* according with new inodebits
*/
ldlm_resource_unlink_lock(lock);
lock->l_policy_data.l_inodebits.bits &= ~to_drop;
ldlm_grant_lock_with_skiplist(lock);
RETURN(0);
}
EXPORT_SYMBOL(ldlm_inodebits_drop);
/* convert single lock */
int ldlm_cli_inodebits_convert(struct ldlm_lock *lock,
enum ldlm_cancel_flags cancel_flags)
{
struct ldlm_namespace *ns = ldlm_lock_to_ns(lock);
struct ldlm_lock_desc ld = { { 0 } };
enum mds_ibits_locks drop_bits, new_bits;
__u32 flags = 0;
int rc;
ENTRY;
check_res_locked(lock->l_resource);
/* Lock is being converted already */
if (ldlm_is_converting(lock)) {
if (!(cancel_flags & LCF_ASYNC)) {
unlock_res_and_lock(lock);
wait_event_idle(lock->l_waitq,
is_lock_converted(lock));
lock_res_and_lock(lock);
}
RETURN(0);
}
/* lru_cancel may happen in parallel and call ldlm_cli_cancel_list()
* independently.
*/
if (ldlm_is_canceling(lock))
RETURN(-EINVAL);
/* no need in only local convert */
if (lock->l_flags & (LDLM_FL_LOCAL_ONLY | LDLM_FL_CANCEL_ON_BLOCK))
RETURN(-EINVAL);
drop_bits = lock->l_policy_data.l_inodebits.cancel_bits;
/* no cancel bits - means that caller needs full cancel */
if (drop_bits == MDS_INODELOCK_NONE)
RETURN(-EINVAL);
new_bits = lock->l_policy_data.l_inodebits.bits & ~drop_bits;
/* check if all lock bits are dropped, proceed with cancel */
if (!new_bits)
RETURN(-EINVAL);
/* check if no dropped bits, consider this as successful convert */
if (lock->l_policy_data.l_inodebits.bits == new_bits)
RETURN(0);
ldlm_set_converting(lock);
/* Finally call cancel callback for remaining bits only.
* It is important to have converting flag during that
* so blocking_ast callback can distinguish convert from
* cancels.
*/
ld.l_policy_data.l_inodebits.cancel_bits = drop_bits;
unlock_res_and_lock(lock);
lock->l_blocking_ast(lock, &ld, lock->l_ast_data, LDLM_CB_CANCELING);
/* now notify server about convert */
rc = ldlm_cli_convert_req(lock, &flags, new_bits);
lock_res_and_lock(lock);
if (rc)
GOTO(full_cancel, rc);
/*
* check that the lock is still actual as it could get
* invalidated by an eviction being unproteced few
* lines above.
*/
if (ldlm_is_failed(lock))
GOTO(full_cancel, rc = -EINVAL);
/* Being locked again check if lock was canceled, it is important
* to do and don't drop cbpending below
*/
if (ldlm_is_canceling(lock))
GOTO(full_cancel, rc = -EINVAL);
/* Finally clear these bits in lock ibits */
ldlm_inodebits_drop(lock, drop_bits);
/* also check again if more bits to be cancelled appeared */
if (drop_bits != lock->l_policy_data.l_inodebits.cancel_bits)
GOTO(clear_converting, rc = -EAGAIN);
/* clear cbpending flag early, it is safe to match lock right after
* client convert because it is downgrade always.
*/
ldlm_clear_cbpending(lock);
ldlm_clear_bl_ast(lock);
spin_lock(&ns->ns_lock);
if (list_empty(&lock->l_lru))
ldlm_lock_add_to_lru_nolock(lock);
spin_unlock(&ns->ns_lock);
/* the job is done, zero the cancel_bits. If more conflicts appear,
* it will result in another cycle of ldlm_cli_inodebits_convert().
*/
full_cancel:
lock->l_policy_data.l_inodebits.cancel_bits = MDS_INODELOCK_NONE;
clear_converting:
ldlm_clear_converting(lock);
RETURN(rc);
}
int ldlm_inodebits_alloc_lock(struct ldlm_lock *lock)
{
if (ldlm_is_ns_srv(lock)) {
int i;
OBD_SLAB_ALLOC_PTR(lock->l_ibits_node, ldlm_inodebits_slab);
if (lock->l_ibits_node == NULL)
return -ENOMEM;
for (i = 0; i < MDS_INODELOCK_NUMBITS; i++)
INIT_LIST_HEAD(&lock->l_ibits_node->lin_link[i]);
lock->l_ibits_node->lock = lock;
} else {
lock->l_ibits_node = NULL;
}
return 0;
}
void ldlm_inodebits_add_lock(struct ldlm_resource *res, struct list_head *head,
struct ldlm_lock *lock, bool tail)
{
int i;
if (!ldlm_is_ns_srv(lock))
return;
if (head == &res->lr_waiting) {
for (i = 0; i < MDS_INODELOCK_NUMBITS; i++) {
if (!(lock->l_policy_data.l_inodebits.bits & BIT(i)))
continue;
if (tail)
list_add_tail(&lock->l_ibits_node->lin_link[i],
&res->lr_ibits_queues->liq_waiting[i]);
else
list_add(&lock->l_ibits_node->lin_link[i],
&res->lr_ibits_queues->liq_waiting[i]);
}
} else if (head == &res->lr_granted && lock->l_ibits_node != NULL) {
for (i = 0; i < MDS_INODELOCK_NUMBITS; i++)
LASSERT(list_empty(&lock->l_ibits_node->lin_link[i]));
OBD_SLAB_FREE_PTR(lock->l_ibits_node, ldlm_inodebits_slab);
lock->l_ibits_node = NULL;
} else if (head != &res->lr_granted) {
/* we are inserting in a middle of a list, after @head */
struct ldlm_lock *orig = list_entry(head, struct ldlm_lock,
l_res_link);
LASSERT(orig->l_policy_data.l_inodebits.bits ==
lock->l_policy_data.l_inodebits.bits);
/* should not insert before with exactly matched set of bits */
LASSERT(tail == false);
for (i = 0; i < MDS_INODELOCK_NUMBITS; i++) {
if (!(lock->l_policy_data.l_inodebits.bits & (1 << i)))
continue;
list_add(&lock->l_ibits_node->lin_link[i],
&orig->l_ibits_node->lin_link[i]);
}
}
}
void ldlm_inodebits_unlink_lock(struct ldlm_lock *lock)
{
int i;
ldlm_unlink_lock_skiplist(lock);
if (!ldlm_is_ns_srv(lock))
return;
for (i = 0; i < MDS_INODELOCK_NUMBITS; i++)
list_del_init(&lock->l_ibits_node->lin_link[i]);
}
