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authorJakob Unterwurzacher2016-11-17 20:32:19 +0100
committerJakob Unterwurzacher2016-11-17 20:32:19 +0100
commite04dc050126edcf7440ea5412bc74c6ad8b42e95 (patch)
tree56affe516cc83618152790582d0a8a6b2c870646 /internal/fusefrontend/write_lock.go
parent081015aa746cc2a37284ad545d56d5ceb78164b6 (diff)
fusefrontend: upgrade wlockMap to use device AND inode number
If there are multiple filesystems backing the gocryptfs filesystems inode numbers are not guaranteed to be unique.
Diffstat (limited to 'internal/fusefrontend/write_lock.go')
-rw-r--r--internal/fusefrontend/write_lock.go46
1 files changed, 31 insertions, 15 deletions
diff --git a/internal/fusefrontend/write_lock.go b/internal/fusefrontend/write_lock.go
index 3addfd6..71e911e 100644
--- a/internal/fusefrontend/write_lock.go
+++ b/internal/fusefrontend/write_lock.go
@@ -3,10 +3,26 @@ 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
+}
+
+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() {
- wlock.inodeLocks = make(map[uint64]*refCntMutex)
+ wlock.inodeLocks = make(map[DevInoStruct]*refCntMutex)
}
// wlock - serializes write accesses to each file (identified by inode number)
@@ -29,7 +45,7 @@ type wlockMap struct {
opCount uint64
// Protects map access
sync.Mutex
- inodeLocks map[uint64]*refCntMutex
+ inodeLocks map[DevInoStruct]*refCntMutex
}
// refCntMutex - mutex with reference count
@@ -42,45 +58,45 @@ type refCntMutex struct {
// register creates an entry for "ino", or incrementes the reference count
// if the entry already exists.
-func (w *wlockMap) register(ino uint64) {
+func (w *wlockMap) register(di DevInoStruct) {
w.Lock()
defer w.Unlock()
- r := w.inodeLocks[ino]
+ r := w.inodeLocks[di]
if r == nil {
r = &refCntMutex{}
- w.inodeLocks[ino] = r
+ w.inodeLocks[di] = r
}
r.refCnt++
}
-// unregister decrements the reference count for "ino" and deletes the entry if
+// unregister decrements the reference count for "di" and deletes the entry if
// the reference count has reached 0.
-func (w *wlockMap) unregister(ino uint64) {
+func (w *wlockMap) unregister(di DevInoStruct) {
w.Lock()
defer w.Unlock()
- r := w.inodeLocks[ino]
+ r := w.inodeLocks[di]
r.refCnt--
if r.refCnt == 0 {
- delete(w.inodeLocks, ino)
+ delete(w.inodeLocks, di)
}
}
-// lock retrieves the entry for "ino" and locks it.
-func (w *wlockMap) lock(ino uint64) {
+// lock retrieves the entry for "di" and locks it.
+func (w *wlockMap) lock(di DevInoStruct) {
atomic.AddUint64(&w.opCount, 1)
w.Lock()
- r := w.inodeLocks[ino]
+ r := w.inodeLocks[di]
w.Unlock()
// this can take a long time - execute outside the wlockMap lock
r.Lock()
}
-// unlock retrieves the entry for "ino" and unlocks it.
-func (w *wlockMap) unlock(ino uint64) {
+// unlock retrieves the entry for "di" and unlocks it.
+func (w *wlockMap) unlock(di DevInoStruct) {
w.Lock()
- r := w.inodeLocks[ino]
+ r := w.inodeLocks[di]
w.Unlock()
r.Unlock()
}