From 863c3ca36fe756767ad2f86348a0646f2e7a09a5 Mon Sep 17 00:00:00 2001
From: Jakob Unterwurzacher
Date: Sun, 2 Apr 2017 21:32:01 +0200
Subject: fusefrontend: rename write_lock.go -> open_file_table.go

The data structure was originally called write lock table, but
is now simply called the open file table. Rename the file to
reflect that.
---
 internal/fusefrontend/write_lock.go | 101 ------------------------------------
 1 file changed, 101 deletions(-)
 delete mode 100644 internal/fusefrontend/write_lock.go

(limited to 'internal/fusefrontend/write_lock.go')

diff --git a/internal/fusefrontend/write_lock.go b/internal/fusefrontend/write_lock.go
deleted file mode 100644
index 053298d..0000000
--- a/internal/fusefrontend/write_lock.go
+++ /dev/null
@@ -1,101 +0,0 @@
-package fusefrontend
-
-import (
-	"sync"
-	"sync/atomic"
-	"syscall"
-)
-
-// DevInoStruct uniquely identifies a backing file through device number and
-// inode number.
-type DevInoStruct struct {
-	dev uint64
-	ino uint64
-}
-
-// DevInoFromStat fills a new DevInoStruct with the passed Stat_t info
-func DevInoFromStat(st *syscall.Stat_t) DevInoStruct {
-	// Explicit cast to uint64 to prevent build problems on 32-bit platforms
-	return DevInoStruct{
-		dev: uint64(st.Dev),
-		ino: uint64(st.Ino),
-	}
-}
-
-func init() {
-	openFileMap.entries = make(map[DevInoStruct]*openFileEntryT)
-}
-
-// wlock - serializes write accesses to each file (identified by inode number)
-// Writing partial blocks means we have to do read-modify-write cycles. We
-// really don't want concurrent writes there.
-// Concurrent full-block writes could actually be allowed, but are not to
-// keep the locking simple.
-var openFileMap openFileMapT
-
-// wlockMap - usage:
-// 1) register
-// 2) lock ... unlock ...
-// 3) unregister
-type openFileMapT struct {
-	// opCount counts writeLock.Lock() calls. As every operation that modifies a file should
-	// call it, this effectively serves as a write-operation counter.
-	// The variable is accessed without holding any locks so atomic operations
-	// must be used. It must be the first element of the struct to guarantee
-	// 64-bit alignment.
-	opCount uint64
-	// Protects map access
-	sync.Mutex
-	entries map[DevInoStruct]*openFileEntryT
-}
-
-type opCountMutex struct {
-	sync.Mutex
-	// Points to the opCount variable of the parent openFileMapT
-	opCount *uint64
-}
-
-func (o *opCountMutex) Lock() {
-	o.Mutex.Lock()
-	atomic.AddUint64(o.opCount, 1)
-}
-
-// refCntMutex - mutex with reference count
-type openFileEntryT struct {
-	// Reference count
-	refCnt int
-	// Write lock for this inode
-	writeLock *opCountMutex
-	// ID is the file ID in the file header.
-	ID     []byte
-	IDLock sync.RWMutex
-}
-
-// register creates an entry for "ino", or incrementes the reference count
-// if the entry already exists.
-func (w *openFileMapT) register(di DevInoStruct) *openFileEntryT {
-	w.Lock()
-	defer w.Unlock()
-
-	r := w.entries[di]
-	if r == nil {
-		o := opCountMutex{opCount: &w.opCount}
-		r = &openFileEntryT{writeLock: &o}
-		w.entries[di] = r
-	}
-	r.refCnt++
-	return r
-}
-
-// unregister decrements the reference count for "di" and deletes the entry if
-// the reference count has reached 0.
-func (w *openFileMapT) unregister(di DevInoStruct) {
-	w.Lock()
-	defer w.Unlock()
-
-	r := w.entries[di]
-	r.refCnt--
-	if r.refCnt == 0 {
-		delete(w.entries, di)
-	}
-}
-- 
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