X-Git-Url: https://git.whamcloud.com/?a=blobdiff_plain;f=lustre%2Fldlm%2Fldlm_inodebits.c;h=4d66c209aae6cf22a6f05fd08a08ed5dbe260243;hb=b0d162390ad63d9dff12295a19022f3152592f7c;hp=cdae39e35641d1fb96522bfbe5a794f1aef1b072;hpb=238a309ea6081163c1928630414ee9767746beaa;p=fs%2Flustre-release.git diff --git a/lustre/ldlm/ldlm_inodebits.c b/lustre/ldlm/ldlm_inodebits.c index cdae39e..4d66c20 100644 --- a/lustre/ldlm/ldlm_inodebits.c +++ b/lustre/ldlm/ldlm_inodebits.c @@ -23,7 +23,7 @@ * Copyright (c) 2004, 2010, Oracle and/or its affiliates. All rights reserved. * Use is subject to license terms. * - * Copyright (c) 2011, 2016, Intel Corporation. + * Copyright (c) 2011, 2017, Intel Corporation. */ /* * This file is part of Lustre, http://www.lustre.org/ @@ -57,6 +57,7 @@ #include "ldlm_internal.h" #ifdef HAVE_SERVER_SUPPORT + /** * Determine if the lock is compatible with all locks on the queue. * @@ -133,11 +134,22 @@ ldlm_inodebits_compat_queue(struct list_head *queue, struct ldlm_lock *req, struct ldlm_lock, l_sl_policy)->l_res_link; - /* drop try_bits used by other locks */ - *try_bits &= ~(lock->l_policy_data.l_inodebits.bits); + /* 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) == 0) 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) { /* COS lock mode has a special compatibility @@ -148,6 +160,7 @@ ldlm_inodebits_compat_queue(struct list_head *queue, struct ldlm_lock *req, ldlm_is_cos_enabled(req) && lock->l_client_cookie == req->l_client_cookie) goto not_conflicting; + /* Found a conflicting policy group. */ if (!work_list) RETURN(0); @@ -191,22 +204,49 @@ int ldlm_process_inodebits_lock(struct ldlm_lock *lock, __u64 *flags, struct list_head *work_list) { struct ldlm_resource *res = lock->l_resource; - struct list_head rpc_list; + struct list_head *grant_work = intention == LDLM_PROCESS_ENQUEUE ? + NULL : work_list; int rc; ENTRY; - LASSERT(lock->l_granted_mode != lock->l_req_mode); - LASSERT(list_empty(&res->lr_converting)); - INIT_LIST_HEAD(&rpc_list); + LASSERT(!ldlm_is_granted(lock)); check_res_locked(res); if (intention == LDLM_PROCESS_RESCAN) { - *err = ELDLM_LOCK_ABORTED; + struct list_head *bl_list; + + if (*flags & LDLM_FL_BLOCK_NOWAIT) { + bl_list = NULL; + *err = ELDLM_LOCK_WOULDBLOCK; + } else { + bl_list = work_list; + *err = ELDLM_LOCK_ABORTED; + } LASSERT(lock->l_policy_data.l_inodebits.bits != 0); - rc = ldlm_inodebits_compat_queue(&res->lr_granted, lock, NULL); + /* 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. + */ + rc = ldlm_inodebits_compat_queue(&res->lr_granted, lock, + bl_list); if (!rc) RETURN(LDLM_ITER_STOP); rc = ldlm_inodebits_compat_queue(&res->lr_waiting, lock, NULL); @@ -217,50 +257,42 @@ int ldlm_process_inodebits_lock(struct ldlm_lock *lock, __u64 *flags, if (lock->l_policy_data.l_inodebits.try_bits != 0) { lock->l_policy_data.l_inodebits.bits |= lock->l_policy_data.l_inodebits.try_bits; + lock->l_policy_data.l_inodebits.try_bits = 0; *flags |= LDLM_FL_LOCK_CHANGED; } ldlm_resource_unlink_lock(lock); - ldlm_grant_lock(lock, work_list); + ldlm_grant_lock(lock, grant_work); *err = ELDLM_OK; RETURN(LDLM_ITER_CONTINUE); } - LASSERT((intention == LDLM_PROCESS_ENQUEUE && work_list == NULL) || - (intention == LDLM_PROCESS_RECOVERY && work_list != NULL)); -restart: - rc = ldlm_inodebits_compat_queue(&res->lr_granted, lock, &rpc_list); - rc += ldlm_inodebits_compat_queue(&res->lr_waiting, lock, &rpc_list); + rc = ldlm_inodebits_compat_queue(&res->lr_granted, lock, work_list); + rc += ldlm_inodebits_compat_queue(&res->lr_waiting, lock, work_list); if (rc != 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) == 0) { - rc = ELDLM_LOCK_WOULDBLOCK; + *err = ELDLM_LOCK_WOULDBLOCK; } else { - rc = ldlm_handle_conflict_lock(lock, flags, - &rpc_list, 0); - if (rc == -ERESTART) - GOTO(restart, rc); + *err = ELDLM_OK; } - *err = rc; } else { /* grant also all remaining try_bits */ if (lock->l_policy_data.l_inodebits.try_bits != 0) { lock->l_policy_data.l_inodebits.bits |= lock->l_policy_data.l_inodebits.try_bits; + lock->l_policy_data.l_inodebits.try_bits = 0; *flags |= LDLM_FL_LOCK_CHANGED; } LASSERT(lock->l_policy_data.l_inodebits.bits); ldlm_resource_unlink_lock(lock); - ldlm_grant_lock(lock, work_list); - rc = 0; + ldlm_grant_lock(lock, grant_work); + *err = ELDLM_OK; } - if (!list_empty(&rpc_list)) - ldlm_discard_bl_list(&rpc_list); - - RETURN(rc); + RETURN(LDLM_ITER_CONTINUE); } #endif /* HAVE_SERVER_SUPPORT */ @@ -279,7 +311,14 @@ void ldlm_ibits_policy_local_to_wire(const union ldlm_policy_data *lpolicy, wpolicy->l_inodebits.try_bits = lpolicy->l_inodebits.try_bits; } -int ldlm_inodebits_drop(struct ldlm_lock *lock, __u64 to_drop) +/** + * 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, __u64 to_drop) { ENTRY; @@ -287,7 +326,7 @@ int ldlm_inodebits_drop(struct ldlm_lock *lock, __u64 to_drop) /* Just return if there are no conflicting bits */ if ((lock->l_policy_data.l_inodebits.bits & to_drop) == 0) { - LDLM_WARN(lock, "try to drop unset bits %#llx/%#llx\n", + LDLM_WARN(lock, "try to drop unset bits %#llx/%#llx", lock->l_policy_data.l_inodebits.bits, to_drop); /* nothing to do */ RETURN(0); @@ -301,3 +340,91 @@ int ldlm_inodebits_drop(struct ldlm_lock *lock, __u64 to_drop) RETURN(0); } EXPORT_SYMBOL(ldlm_inodebits_drop); + +/* convert single lock */ +int ldlm_cli_dropbits(struct ldlm_lock *lock, __u64 drop_bits) +{ + struct lustre_handle lockh; + __u32 flags = 0; + int rc; + + ENTRY; + + LASSERT(drop_bits); + LASSERT(!lock->l_readers && !lock->l_writers); + + LDLM_DEBUG(lock, "client lock convert START"); + + ldlm_lock2handle(lock, &lockh); + lock_res_and_lock(lock); + /* check if all bits are blocked */ + if (!(lock->l_policy_data.l_inodebits.bits & ~drop_bits)) { + unlock_res_and_lock(lock); + /* return error to continue with cancel */ + GOTO(exit, rc = -EINVAL); + } + + /* check if no common bits, consider this as successful convert */ + if (!(lock->l_policy_data.l_inodebits.bits & drop_bits)) { + unlock_res_and_lock(lock); + GOTO(exit, rc = 0); + } + + /* check if there is race with cancel */ + if (ldlm_is_canceling(lock) || ldlm_is_cancel(lock)) { + unlock_res_and_lock(lock); + GOTO(exit, rc = -EINVAL); + } + + /* 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); + + /* If lock is being converted already, check drop bits first */ + if (ldlm_is_converting(lock)) { + /* raced lock convert, lock inodebits are remaining bits + * so check if they are conflicting with new convert or not. + */ + if (!(lock->l_policy_data.l_inodebits.bits & drop_bits)) { + unlock_res_and_lock(lock); + GOTO(exit, rc = 0); + } + /* Otherwise drop new conflicting bits in new convert */ + } + ldlm_set_converting(lock); + /* from all bits of blocking lock leave only conflicting */ + drop_bits &= lock->l_policy_data.l_inodebits.bits; + /* save them in cancel_bits, so l_blocking_ast will know + * which bits from the current lock were dropped. */ + lock->l_policy_data.l_inodebits.cancel_bits = drop_bits; + /* Finally clear these bits in lock ibits */ + ldlm_inodebits_drop(lock, drop_bits); + unlock_res_and_lock(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. + */ + if (lock->l_blocking_ast) + lock->l_blocking_ast(lock, NULL, lock->l_ast_data, + LDLM_CB_CANCELING); + + /* now notify server about convert */ + rc = ldlm_cli_convert(lock, &flags); + if (rc) { + lock_res_and_lock(lock); + if (ldlm_is_converting(lock)) { + ldlm_clear_converting(lock); + ldlm_set_cbpending(lock); + ldlm_set_bl_ast(lock); + } + unlock_res_and_lock(lock); + GOTO(exit, rc); + } + EXIT; +exit: + LDLM_DEBUG(lock, "client lock convert END"); + return rc; +}