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Message-Id: <1443672762-982936-32-git-send-email-green@linuxhacker.ru> Date: Thu, 1 Oct 2015 00:12:41 -0400 From: green@...uxhacker.ru To: Greg Kroah-Hartman <gregkh@...uxfoundation.org>, devel@...verdev.osuosl.org, Andreas Dilger <andreas.dilger@...el.com> Cc: Linux Kernel Mailing List <linux-kernel@...r.kernel.org>, Lustre Development List <lustre-devel@...ts.lustre.org>, Oleg Drokin <green@...uxhacker.ru> Subject: [PATCH 31/32] staging/lustre/ldlm: Remove posix lock (flock) deadlock detection From: Oleg Drokin <green@...uxhacker.ru> This is server-side code that cannot work on the client (vfs would do this check on the local node). Signed-off-by: Oleg Drokin <green@...uxhacker.ru> --- drivers/staging/lustre/lustre/ldlm/ldlm_flock.c | 132 ------------------------ 1 file changed, 132 deletions(-) diff --git a/drivers/staging/lustre/lustre/ldlm/ldlm_flock.c b/drivers/staging/lustre/lustre/ldlm/ldlm_flock.c index 57b4edb..0c46a06 100644 --- a/drivers/staging/lustre/lustre/ldlm/ldlm_flock.c +++ b/drivers/staging/lustre/lustre/ldlm/ldlm_flock.c @@ -91,40 +91,6 @@ ldlm_flocks_overlap(struct ldlm_lock *lock, struct ldlm_lock *new) lock->l_policy_data.l_flock.start)); } -static inline void ldlm_flock_blocking_link(struct ldlm_lock *req, - struct ldlm_lock *lock) -{ - /* For server only */ - if (req->l_export == NULL) - return; - - LASSERT(hlist_unhashed(&req->l_exp_flock_hash)); - - req->l_policy_data.l_flock.blocking_owner = - lock->l_policy_data.l_flock.owner; - req->l_policy_data.l_flock.blocking_export = - lock->l_export; - req->l_policy_data.l_flock.blocking_refs = 0; - - cfs_hash_add(req->l_export->exp_flock_hash, - &req->l_policy_data.l_flock.owner, - &req->l_exp_flock_hash); -} - -static inline void ldlm_flock_blocking_unlink(struct ldlm_lock *req) -{ - /* For server only */ - if (req->l_export == NULL) - return; - - check_res_locked(req->l_resource); - if (req->l_export->exp_flock_hash != NULL && - !hlist_unhashed(&req->l_exp_flock_hash)) - cfs_hash_del(req->l_export->exp_flock_hash, - &req->l_policy_data.l_flock.owner, - &req->l_exp_flock_hash); -} - static inline void ldlm_flock_destroy(struct ldlm_lock *lock, ldlm_mode_t mode, __u64 flags) { @@ -149,79 +115,6 @@ ldlm_flock_destroy(struct ldlm_lock *lock, ldlm_mode_t mode, __u64 flags) } /** - * POSIX locks deadlock detection code. - * - * Given a new lock \a req and an existing lock \a bl_lock it conflicts - * with, we need to iterate through all blocked POSIX locks for this - * export and see if there is a deadlock condition arising. (i.e. when - * one client holds a lock on something and want a lock on something - * else and at the same time another client has the opposite situation). - */ -static int -ldlm_flock_deadlock(struct ldlm_lock *req, struct ldlm_lock *bl_lock) -{ - struct obd_export *req_exp = req->l_export; - struct obd_export *bl_exp = bl_lock->l_export; - __u64 req_owner = req->l_policy_data.l_flock.owner; - __u64 bl_owner = bl_lock->l_policy_data.l_flock.owner; - - /* For server only */ - if (req_exp == NULL) - return 0; - - class_export_get(bl_exp); - while (1) { - struct obd_export *bl_exp_new; - struct ldlm_lock *lock = NULL; - struct ldlm_flock *flock; - - if (bl_exp->exp_flock_hash != NULL) - lock = cfs_hash_lookup(bl_exp->exp_flock_hash, - &bl_owner); - if (lock == NULL) - break; - - LASSERT(req != lock); - flock = &lock->l_policy_data.l_flock; - LASSERT(flock->owner == bl_owner); - bl_owner = flock->blocking_owner; - bl_exp_new = class_export_get(flock->blocking_export); - class_export_put(bl_exp); - - cfs_hash_put(bl_exp->exp_flock_hash, &lock->l_exp_flock_hash); - bl_exp = bl_exp_new; - - if (bl_owner == req_owner && bl_exp == req_exp) { - class_export_put(bl_exp); - return 1; - } - } - class_export_put(bl_exp); - - return 0; -} - -static void ldlm_flock_cancel_on_deadlock(struct ldlm_lock *lock, - struct list_head *work_list) -{ - CDEBUG(D_INFO, "reprocess deadlock req=%p\n", lock); - - if ((exp_connect_flags(lock->l_export) & - OBD_CONNECT_FLOCK_DEAD) == 0) { - CERROR( - "deadlock found, but client doesn't support flock canceliation\n"); - } else { - LASSERT(lock->l_completion_ast); - LASSERT((lock->l_flags & LDLM_FL_AST_SENT) == 0); - lock->l_flags |= LDLM_FL_AST_SENT | LDLM_FL_CANCEL_ON_BLOCK | - LDLM_FL_FLOCK_DEADLOCK; - ldlm_flock_blocking_unlink(lock); - ldlm_resource_unlink_lock(lock); - ldlm_add_ast_work_item(lock, NULL, work_list); - } -} - -/** * Process a granting attempt for flock lock. * Must be called under ns lock held. * @@ -307,11 +200,6 @@ reprocess: if (!first_enq) { reprocess_failed = 1; - if (ldlm_flock_deadlock(req, lock)) { - ldlm_flock_cancel_on_deadlock(req, - work_list); - return LDLM_ITER_CONTINUE; - } continue; } @@ -334,17 +222,6 @@ reprocess: return LDLM_ITER_STOP; } - /* add lock to blocking list before deadlock - * check to prevent race */ - ldlm_flock_blocking_link(req, lock); - - if (ldlm_flock_deadlock(req, lock)) { - ldlm_flock_blocking_unlink(req); - ldlm_flock_destroy(req, mode, *flags); - *err = -EDEADLK; - return LDLM_ITER_STOP; - } - ldlm_resource_add_lock(res, &res->lr_waiting, req); *flags |= LDLM_FL_BLOCK_GRANTED; return LDLM_ITER_STOP; @@ -360,10 +237,6 @@ reprocess: return LDLM_ITER_STOP; } - /* In case we had slept on this lock request take it off of the - * deadlock detection hash list. */ - ldlm_flock_blocking_unlink(req); - /* Scan the locks owned by this process that overlap this request. * We may have to merge or split existing locks. */ @@ -551,9 +424,7 @@ ldlm_flock_interrupted_wait(void *data) lock = ((struct ldlm_flock_wait_data *)data)->fwd_lock; - /* take lock off the deadlock detection hash list. */ lock_res_and_lock(lock); - ldlm_flock_blocking_unlink(lock); /* client side - set flag to prevent lock from being put on LRU list */ lock->l_flags |= LDLM_FL_CBPENDING; @@ -660,9 +531,6 @@ granted: lock_res_and_lock(lock); - /* take lock off the deadlock detection hash list. */ - ldlm_flock_blocking_unlink(lock); - /* ldlm_lock_enqueue() has already placed lock on the granted list. */ list_del_init(&lock->l_res_link); -- 2.1.0 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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