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xCheckReservedLock.

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Nuno Cruces
2023-01-25 00:33:01 +00:00
parent dbfddf2c5b
commit 3763b06187
2 changed files with 41 additions and 10 deletions
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42
vfs_lock.go
View File

@@ -53,13 +53,16 @@ const (
)
type vfsLocker interface {
LockState() uint32
LockerState() uint32
LockShared() uint32 // UNLOCKED -> SHARED
LockReserved() uint32 // SHARED -> RESERVED
LockPending() uint32 // SHARED|RESERVED -> (PENDING)
LockPending() uint32 // SHARED|RESERVED -> PENDING
LockExclusive() uint32 // PENDING -> EXCLUSIVE
DowngradeLock() uint32 // SHARED <- EXCLUSIVE|PENDING|RESERVED
ReleaseLock() uint32 // UNLOCKED <- EXCLUSIVE|PENDING|RESERVED|SHARED
CheckReserved() (bool, uint32)
}
func vfsLock(ctx context.Context, mod api.Module, pFile, eLock uint32) uint32 {
@@ -81,7 +84,7 @@ func vfsLock(ctx context.Context, mod api.Module, pFile, eLock uint32) uint32 {
// We never move from unlocked to anything higher than shared lock.
panic(assertErr + " [pfa77m]")
case cLock != _SHARED_LOCK && eLock == _RESERVED_LOCK:
// A shared lock is always held when a reserve lock is requested.
// A shared lock is always held when a reserved lock is requested.
panic(assertErr + " [5cfmsp]")
}
}
@@ -89,7 +92,7 @@ func vfsLock(ctx context.Context, mod api.Module, pFile, eLock uint32) uint32 {
vfsOpenFilesMtx.Lock()
defer vfsOpenFilesMtx.Unlock()
of := vfsOpenFiles[ptr.ID()]
fLock := of.LockState()
fLock := of.LockerState()
// If some other connection has a lock that precludes the requested lock, return BUSY.
if cLock != fLock && (eLock > _SHARED_LOCK || fLock >= _PENDING_LOCK) {
@@ -152,7 +155,7 @@ func vfsLock(ctx context.Context, mod api.Module, pFile, eLock uint32) uint32 {
}
}
func vfsUnlock(ctx context.Context, mod api.Module, pFile, eLock uint32) (rc uint32) {
func vfsUnlock(ctx context.Context, mod api.Module, pFile, eLock uint32) uint32 {
if assert && (eLock != _NO_LOCK && eLock != _SHARED_LOCK) {
panic(assertErr + " [7i4jw3]")
}
@@ -168,7 +171,7 @@ func vfsUnlock(ctx context.Context, mod api.Module, pFile, eLock uint32) (rc uin
vfsOpenFilesMtx.Lock()
defer vfsOpenFilesMtx.Unlock()
of := vfsOpenFiles[ptr.ID()]
fLock := of.LockState()
fLock := of.LockerState()
if assert && of.shared <= 0 {
panic(assertErr + " [2bhkwg]")
@@ -183,8 +186,7 @@ func vfsUnlock(ctx context.Context, mod api.Module, pFile, eLock uint32) (rc uin
// process is holding an incompatible lock. If it does, this
// indicates that the other process is not following the locking
// protocol. If this happens, return IOERR_RDLOCK. Returning
// BUSY would confuse the upper layer (in practice it causes
// an assert to fail).
// BUSY would confuse the upper layer.
return uint32(IOERR_RDLOCK)
}
ptr.SetLock(_SHARED_LOCK)
@@ -217,6 +219,28 @@ func vfsUnlock(ctx context.Context, mod api.Module, pFile, eLock uint32) (rc uin
}
func vfsCheckReservedLock(ctx context.Context, mod api.Module, pFile, pResOut uint32) uint32 {
mod.Memory().WriteUint32Le(pResOut, 0)
ptr := vfsFilePtr{mod, pFile}
cLock := ptr.Lock()
if assert && cLock > _SHARED_LOCK {
panic(assertErr + " [zarygt]")
}
vfsOpenFilesMtx.Lock()
defer vfsOpenFilesMtx.Unlock()
of := vfsOpenFiles[ptr.ID()]
locked, rc := of.CheckReserved()
if rc != _OK {
return uint32(IOERR_CHECKRESERVEDLOCK)
}
var res uint32
if locked {
res = 1
}
if ok := mod.Memory().WriteUint32Le(pResOut, res); !ok {
panic(rangeErr)
}
return _OK
}

9
vfs_lock_debug.go
View File

@@ -8,7 +8,7 @@ type vfsDebugLocker struct {
var _ vfsLocker = &vfsDebugLocker{}
func (l *vfsDebugLocker) LockState() uint32 {
func (l *vfsDebugLocker) LockerState() uint32 {
return l.state
}
@@ -59,3 +59,10 @@ func (l *vfsDebugLocker) ReleaseLock() uint32 {
l.state = _NO_LOCK
return _OK
}
func (l *vfsDebugLocker) CheckReserved() (bool, uint32) {
if l.state > _SHARED_LOCK {
return true, _OK
}
return false, _OK
}