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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
--
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