Commit f40a24c8 authored by Aaron Jacobs's avatar Aaron Jacobs

Pay attention to DisableWritebackCaching.

parent 842af250
......@@ -57,6 +57,7 @@ const maxReadahead = 1 << 20
// A connection to the fuse kernel process.
type Connection struct {
cfg MountConfig
debugLogger *log.Logger
errorLogger *log.Logger
......@@ -65,9 +66,6 @@ type Connection struct {
dev *os.File
protocol fusekernel.Protocol
// The context from which all op contexts inherit.
parentCtx context.Context
mu sync.Mutex
// A map from fuse "unique" request ID (*not* the op ID for logging used
......@@ -94,15 +92,15 @@ type opState struct {
//
// The loggers may be nil.
func newConnection(
parentCtx context.Context,
cfg MountConfig,
debugLogger *log.Logger,
errorLogger *log.Logger,
dev *os.File) (c *Connection, err error) {
c = &Connection{
cfg: cfg,
debugLogger: debugLogger,
errorLogger: errorLogger,
dev: dev,
parentCtx: parentCtx,
cancelFuncs: make(map[uint64]func()),
}
......@@ -165,12 +163,10 @@ func (c *Connection) Init() (err error) {
// Tell the kernel not to use pitifully small 4 KiB writes.
initOp.Flags |= fusekernel.InitBigWrites
// TODO(jacobsa): Make this opt out and discuss benefits and caveats:
// * Write performance may be better (cf. http://thread.gmane.org/gmane.comp.file-systems.fuse.devel/13923)
// * (Discuss what writeback caching even means)
// * File systems need to implement setattr for dealing with kernel's stored time (find code reference)
// * File systems no longer "own" mtime; kernel will cache it even if no writes (cf. http://thread.gmane.org/gmane.comp.file-systems.fuse.devel/14808)
initOp.Flags |= fusekernel.InitWritebackCache
// Enable writeback caching if the user hasn't asked us not to.
if !c.cfg.DisableWritebackCaching {
initOp.Flags |= fusekernel.InitWritebackCache
}
c.Reply(ctx, nil)
return
......@@ -234,7 +230,7 @@ func (c *Connection) beginOp(
opCode uint32,
fuseID uint64) (ctx context.Context) {
// Start with the parent context.
ctx = c.parentCtx
ctx = c.cfg.OpContext
// Set up a cancellation function.
//
......
......@@ -67,14 +67,14 @@ func Mount(
}
// Choose a parent context for ops.
opContext := config.OpContext
if opContext == nil {
opContext = context.Background()
cfgCopy := *config
if cfgCopy.OpContext == nil {
cfgCopy.OpContext = context.Background()
}
// Create a Connection object wrapping the device.
connection, err := newConnection(
opContext,
cfgCopy,
config.DebugLogger,
config.ErrorLogger,
dev)
......
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