LU-10958 ofd: data corruption due to RPC reordering

[fs/lustre-release.git] / lustre / include / range_lock.h

diff --git a/lustre/include/range_lock.h b/lustre/include/range_lock.h
new file mode 100644 (file)
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+++ b/lustre/include/range_lock.h
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+/*
+ * GPL HEADER START
+ *
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 only,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License version 2 for more details (a copy is included
+ * in the LICENSE file that accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License
+ * version 2 along with this program; If not, see
+ * http://www.gnu.org/licenses/gpl-2.0.html
+ *
+ * GPL HEADER END
+ */
+/*
+ * Range lock is used to allow multiple threads writing a single shared
+ * file given each thread is writing to a non-overlapping portion of the
+ * file.
+ *
+ * Refer to the possible upstream kernel version of range lock by
+ * Jan Kara <jack@suse.cz>: https://lkml.org/lkml/2013/1/31/480
+ *
+ * This file could later replaced by the upstream kernel version.
+ */
+/*
+ * Author: Prakash Surya <surya1@llnl.gov>
+ * Author: Bobi Jam <bobijam.xu@intel.com>
+ */
+#ifndef _RANGE_LOCK_H
+#define _RANGE_LOCK_H
+
+#include <libcfs/libcfs.h>
+#include <interval_tree.h>
+
+#define RL_FMT "[%llu, %llu]"
+#define RL_PARA(range)                         \
+       (range)->rl_node.in_extent.start,       \
+       (range)->rl_node.in_extent.end
+
+struct range_lock {
+       struct interval_node    rl_node;
+       /**
+        * Process to enqueue this lock.
+        */
+       struct task_struct      *rl_task;
+       /**
+        * List of locks with the same range.
+        */
+       struct list_head        rl_next_lock;
+       /**
+        * Number of locks in the list rl_next_lock
+        */
+       unsigned int            rl_lock_count;
+       /**
+        * Number of ranges which are blocking acquisition of the lock
+        */
+       unsigned int            rl_blocking_ranges;
+       /**
+        * Sequence number of range lock. This number is used to get to know
+        * the order the locks are queued; this is required for range_cancel().
+        */
+       __u64                   rl_sequence;
+};
+
+static inline struct range_lock *node2rangelock(const struct interval_node *n)
+{
+       return container_of(n, struct range_lock, rl_node);
+}
+
+struct range_lock_tree {
+       struct interval_node    *rlt_root;
+       spinlock_t               rlt_lock;
+       __u64                    rlt_sequence;
+};
+
+void range_lock_tree_init(struct range_lock_tree *tree);
+int  range_lock_init(struct range_lock *lock, __u64 start, __u64 end);
+int  range_lock(struct range_lock_tree *tree, struct range_lock *lock);
+void range_unlock(struct range_lock_tree *tree, struct range_lock *lock);
+#endif