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authorDavid Teigland <teigland@redhat.com>2013-04-05 10:57:15 +0100
committerDavid Teigland <teigland@redhat.com>2013-04-08 12:03:15 -0500
commit900083183959107159f962b83b3b439d53796499 (patch)
tree45827ae0ce336cc0767bcb09938772df4497a809
parent31880c37c11e28cb81c70757e38392b42e695dc6 (diff)
dlm: avoid unnecessary posix unlock
When the kernel clears flocks/plocks during close, it calls posix unlock when there are flocks but no posix locks. Without this patch, that unnecessary posix unlock is passed to userland (dlm_controld), across the cluster, and back to the kernel. This can create a lot of plock activity, even when no posix locks had been used. This patch copies the nfs approach, and skips the full posix unlock if there is no plock found during the vfs unlock phase. Signed-off-by: David Teigland <teigland@redhat.com>
-rw-r--r--fs/dlm/plock.c18
1 files changed, 15 insertions, 3 deletions
diff --git a/fs/dlm/plock.c b/fs/dlm/plock.c
index 01fd5c11a7f..f704458ea5f 100644
--- a/fs/dlm/plock.c
+++ b/fs/dlm/plock.c
@@ -247,6 +247,7 @@ int dlm_posix_unlock(dlm_lockspace_t *lockspace, u64 number, struct file *file,
struct dlm_ls *ls;
struct plock_op *op;
int rv;
+ unsigned char fl_flags = fl->fl_flags;
ls = dlm_find_lockspace_local(lockspace);
if (!ls)
@@ -258,9 +259,18 @@ int dlm_posix_unlock(dlm_lockspace_t *lockspace, u64 number, struct file *file,
goto out;
}
- if (posix_lock_file_wait(file, fl) < 0)
- log_error(ls, "dlm_posix_unlock: vfs unlock error %llx",
- (unsigned long long)number);
+ /* cause the vfs unlock to return ENOENT if lock is not found */
+ fl->fl_flags |= FL_EXISTS;
+
+ rv = posix_lock_file_wait(file, fl);
+ if (rv == -ENOENT) {
+ rv = 0;
+ goto out_free;
+ }
+ if (rv < 0) {
+ log_error(ls, "dlm_posix_unlock: vfs unlock error %d %llx",
+ rv, (unsigned long long)number);
+ }
op->info.optype = DLM_PLOCK_OP_UNLOCK;
op->info.pid = fl->fl_pid;
@@ -296,9 +306,11 @@ int dlm_posix_unlock(dlm_lockspace_t *lockspace, u64 number, struct file *file,
if (rv == -ENOENT)
rv = 0;
+out_free:
kfree(op);
out:
dlm_put_lockspace(ls);
+ fl->fl_flags = fl_flags;
return rv;
}
EXPORT_SYMBOL_GPL(dlm_posix_unlock);