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Levin Zimmermann
go-fuse
Commits
bedd3b65
Commit
bedd3b65
authored
Feb 28, 2019
by
Kirill Smelkov
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X incomplete review of newapi 2
many things from na1.patch still not yet integrated back.
parent
48be1a10
Changes
6
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6 changed files
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588 additions
and
26 deletions
+588
-26
na1.patch
na1.patch
+518
-0
nodefs/api.go
nodefs/api.go
+23
-5
nodefs/bridge.go
nodefs/bridge.go
+7
-2
nodefs/default.go
nodefs/default.go
+10
-0
nodefs/inode.go
nodefs/inode.go
+22
-13
nodefs/loopback.go
nodefs/loopback.go
+8
-6
No files found.
na1.patch
0 → 100644
View file @
bedd3b65
diff --git a/nodefs/bridge.go b/nodefs/bridge.go
index d51e897..5169a37 100644
--- a/nodefs/bridge.go
+++ b/nodefs/bridge.go
@@ -29,9 +29,15 @@
type rawBridge struct {
options Options
root *Inode
+ // we maintain index
+ //
+ // ID -> inode
+ //
+ // so that we can serve FUSE operational requests where nodes are specified by
+ // their ID.
mu sync.Mutex
- nodes []mapEntry
- free []uint64
+ nodes []mapEntry // ID -> Inode; some inodes may be here in "forgotten" state not yet removed
+ free []uint64 // free ID
files []fileEntry
freeFiles []uint64
@@ -70,65 +76,308 @@
func NewNodeFS(root Node, opts *Options) fuse.RawFileSystem {
return bridge
}
+// XXX kill?
func (b *rawBridge) inode(id uint64, fh uint64) (*Inode, fileEntry) {
- b.mu.Lock()
- defer b.mu.Unlock()
+// b.mu.Lock()
+// defer b.mu.Unlock() // XXX not good to return with released lock
return b.nodes[id].inode, b.files[fh]
}
-func (b *rawBridge) Lookup(header *fuse.InHeader, name string, out *fuse.EntryOut) (status fuse.Status) {
- parent, _ := b.inode(header.NodeId, 0)
+// Lookup & Forget
+//
+// Lookup checks inode.children and potentially calls inode.node.Lookup;
+// increments ichild.lookupCount. Forget decrements inode.lookupCount and, if
+// that reaches 0, unregisters inode from its parents.
+//
+// To avoid races, whenever we need to update group of inodes (for example
+// inode and its parents) we take locks on all inodes in the group.
+//
+// Before getting to take locks on a group, we start from locking only one
+// inode - the inode in question itself. This is required becuase we need to
+// first inspect the inode to decide what to do next and what is the inode
+// group to change.
+//
+// Going from only one inode locked to locked inode group requires to unlock
+// the inode in the middle. This creates possibility that at the time when
+// inode group will be locked, the inode itself was already changed. If the
+// inode was indeed changed, we restart the whole procedure.
+//
+// Inode.changeCounter is used to detect if inode was changed or not - it is
+// incremented every time the inode is modified.
+//
+// rawBridge.mu (the lock for ID -> inode index) is locked either:
+//
+// - on its own, or
+// - always after locking some inodes.
+//
+// it is never locked the other way (e.g. rawBridge.mu -> inode).
+//
+//
+// Note on FUSE FORGET semantic: Forget(inodeID) means filesystem client
+// (usually the kernel) evicts inode from its cache. It can happen that the
+// inode is directory and it children inodes are still kept in client cache
+// with nlookup > 0. If we see such a forgotten directory, we don't unlink it
+// from the tree until all of its children are also forgotten.
- child, code := parent.node.Lookup(context.TODO(), name, out)
- if !code.Ok() {
- if b.options.NegativeTimeout != nil {
- out.SetEntryTimeout(*b.options.NegativeTimeout)
+func (b *rawBridge) Forget(nodeid, nlookup uint64) {
+ b.mu.Lock()
+ inode := b.nodes[nodeid].inode
+ b.mu.Unlock()
+
+ // XXX if inode == nil || already forgoten -> log (client bug)
+ b.forgetInode(inode, nlookup)
+}
+
+func (b *rawBridge) forgetInode(inode *Inode, nlookup uint64) {
+ // lock inode, extract parents, unlock inode, relock(inode, parents),
+ // verify that inode had not changed (and retry if it changed), and
+ // perform unlinking.
+retry:
+ for {
+ inode.mu.Lock()
+ if nlookup != 0 {
+ inode.lookupCount -= nlookup // XXX log if it goes < 0
+ inode.changeCounter++
}
- return code
+ if inode.lookupCount != 0 {
+ inode.mu.Unlock()
+ return
+ }
+
+ // don't perform unlinking if inode was already forgotten.
+ //
+ // Examples when inode could be already forgotten:
+ //
+ // - if Forget, in between inode -> inode + parents relock, was
+ // interrupted by Lookup + another Forget -> we could retry here
+ // with the inode already forgotten.
+ //
+ // - if inode is directory and its forgetting was delayed due
+ // to alive children, the forget could be triggered by last
+ // forgotten children, which could be simultaneous with new
+ // Lookup and again Forget.
+ if inode.nodeID == 0 {
+ inode.mu.Unlock()
+ return
+ }
+
+ if len(inode.children) != 0 {
+ // client forgot about directory, but not about its children.
+ // delay directory inode forget to until children are alive.
+ inode.mu.Unlock()
+ return
+ }
+
+ // relock inode + parents.
+ // If inode stays the same - perform the forget; retry otherwise.
+
+ nlookup = 0 // make sure not to change lookupCount again, if we'll be retrying
+ lockv := []*Inode{inode}
+ for p := range inode.parents {
+ lockv = append(lockv, p.parent)
+ }
+
+ inodeVer := inode.changeCounter
+ inode.mu.Unlock()
+ lockNodes(lockv...)
+ if inodeVer != inode.changeCounter {
+ unlockNodes(lockv...)
+ continue retry
+ }
+
+ // we have locks on inode and .parents; let's unlink and forget
+ // inode. Also check if for unlinked parents forget was delayed,
+ // and if so and we are last child - do the forget on parent.
+ delayedForget := map[*Inode]struct{}{}
+ for p := range inode.parents {
+ iparent := p.parent
+ delete(iparent.children, p.name)
+ iparent.changeCounter++
+
+ // if parent was a directory with delayed forget and we
+ // were the last of its children - now is the time to
+ // do forget on the parent.
+ if iparent.lookupCount == 0 && len(iparent.children) == 0 {
+ delayedForget[iparent] = struct{}{}
+ }
+ }
+
+ nodeID := inode.nodeID
+ inode.nodeID = 0 // forgotten
+ inode.parents = map[parentData]struct{}{} // clear
+ inode.changeCounter++
+
+ unlockNodes(lockv...)
+
+ // release nodeID. In the meantime, while we were not holding
+ // b.mu locked and inode was forgotten, the ID could be already
+ // reused. So check if it is not the case.
+ b.mu.Lock()
+ if b.nodes[nodeID].inode == inode {
+ b.free = append(b.free, nodeID)
+ b.nodes[nodeID].inode = nil
+ }
+ b.mu.Unlock()
+
+ // execute delayed forget on parents
+ for iparent := range delayedForget {
+ b.forgetInode(iparent, 0)
+ }
+
+ // done
+ return
}
+}
+func (b *rawBridge) Lookup(header *fuse.InHeader, name string, out *fuse.EntryOut) (status fuse.Status) {
b.mu.Lock()
- defer b.mu.Unlock()
+ pentry := b.nodes[header.NodeId]
+ b.mu.Unlock()
- lockNodes(parent, child)
- parent.addLookup(name, child)
- unlockNodes(parent, child)
+ iparent := pentry.inode
- if child.nodeID == 0 {
- b.registerInode(child)
+ if iparent == nil {
+ return fuse.ENOENT // FIXME errcode=ok?
}
- out.NodeId = child.nodeID
- out.Generation = b.nodes[child.nodeID].generation
+retry:
+ for {
+ iparent.mu.Lock()
+ if iparent.nodeID == 0 {
+ iparent.mu.Unlock()
+ return fuse.ENOENT // forgotten XXX errcode=ok?
+ }
- if b.options.AttrTimeout != nil {
- out.SetAttrTimeout(*b.options.AttrTimeout)
- }
- if b.options.EntryTimeout != nil {
- out.SetEntryTimeout(*b.options.EntryTimeout)
- }
+ if iparent.mode&fuse.S_IFDIR == 0 {
+ iparent.mu.Unlock()
+ return fuse.ENOTDIR
+ }
- return fuse.OK
+ // if parent already has inode for this name - we can use it
+ ichild := iparent.children[name]
+ if ichild != nil {
+ // relock iparent + ichild; retry if iparent changed
+ iparentVer := iparent.changeCounter
+ iparent.mu.Unlock()
+ lockNodes(iparent, ichild)
+ if iparentVer != iparent.changeCounter {
+ unlockNodes(iparent, ichild)
+ continue retry
+ }
+ }
+
+ // iparent & ichild are locked; ichild might be nil.
+ lockv := []*Inode{iparent, ichild}
+ ichildNew := false
+ if ichild == nil {
+ // this goroutine becomes reponsible to call node.Lookup
+ // TODO place lookup-in-progress inode and do Lookup without iparent lock
+
+ child, code := iparent.node.Lookup(context.TODO(), name, out)
+ if !code.Ok() {
+ iparent.mu.Unlock()
+ if b.options.NegativeTimeout != nil {
+ out.SetEntryTimeout(*b.options.NegativeTimeout)
+ }
+ return code
+ }
+
+ ichild := newInode(child, out.Attr.Mode) // XXX + bridge
+ ichildNew = true
+ ok := child.setInode(ichild)
+ if !ok {
+ // someone concurrently going to this node (via
+ // different path), already set node -> inode
+ // assocation. This can happen e.g. if for
+ //
+ // root
+ // / \
+ // dir1 dir2
+ // \ /
+ // file
+ //
+ // dir1.Lookup("file") and dir2.Lookup("file") are executed simultaneously.
+ //
+ // we have to use that inode.
+ ichild = child.inode()
+
+ // relock to iparent + ichild and retry if iparent changes.
+ iparentVer := iparent.changeCounter
+ iparent.mu.Unlock()
+ lockNodes(iparent, ichild)
+ if iparentVer != iparent.changeCounter {
+ unlockNodes(iparent, ichild)
+ continue retry
+ }
+
+ ichildNew = false
+ lockv[1] = ichild
+ }
+ }
+
+ // now either:
+ //
+ // - iparent & ichild are locked, or
+ // - iparent is locked and ichild was just created anew.
+ //
+ // (what was locked is covered by lockv)
+ //
+ // -> perform `iparent <-> ichild` linking.
+ iparent.setEntry(name, ichild)
+ ichild.lookupCount++ // XXX ichild.changeCounter++ is in setEntry
+
+ // if ichild was created anew - we have to register ID for it.
+ // retrieve child generation while b is locked along the way.
+ b.mu.Lock()
+ if ichildNew {
+ b.registerInode(ichild)
+ }
+ childID := ichild.nodeID
+ childGen := b.nodes[childID].generation
+ b.mu.Unlock()
+
+ // release iparent + (ichild)? locks and we are done
+ unlockNodes(lockv...)
+
+ out.NodeId = childID
+ out.Generation = childGen
+
+ if b.options.AttrTimeout != nil {
+ out.SetAttrTimeout(*b.options.AttrTimeout)
+ }
+ if b.options.EntryTimeout != nil {
+ out.SetEntryTimeout(*b.options.EntryTimeout)
+ }
+
+ return fuse.OK
+ }
}
-func (b *rawBridge) registerInode(child *Inode) {
+// registerInode allocates new inode ID and registers inode with that ID to
+// inode ID index.
+//
+// must be called with inode and b locked.
+func (b *rawBridge) registerInode(inode *Inode) {
if l := len(b.free); l > 0 {
last := b.free[l-1]
b.free = b.free[:l-1]
- child.nodeID = last
- b.nodes[last].inode = child
+ inode.nodeID = last
+ b.nodes[last].inode = inode
b.nodes[last].generation++
} else {
last := len(b.nodes)
b.nodes = append(b.nodes, mapEntry{
- inode: child,
+ inode: inode,
})
- child.nodeID = uint64(last)
+ inode.nodeID = uint64(last)
}
+ inode.changeCounter++
}
func (b *rawBridge) Create(input *fuse.CreateIn, name string, out *fuse.CreateOut) (code fuse.Status) {
+ panic("TODO - similarly to Lookup")
+/*
ctx := context.TODO()
parent, _ := b.inode(input.NodeId, 0)
child, f, flags, code := parent.node.Create(ctx, name, input.Flags, input.Mode)
@@ -163,8 +412,11 @@
func (b *rawBridge) Create(input *fuse.CreateIn, name string, out *fuse.CreateOu
f.GetAttr(ctx, &out.Attr)
return fuse.OK
+*/
}
+// XXX move -> near Lookup, so that the interaction between Forget/Lookup is easier to oversee
+/*
func (b *rawBridge) Forget(nodeid, nlookup uint64) {
b.mu.Lock()
defer b.mu.Unlock()
@@ -179,6 +431,7 @@
func (b *rawBridge) Forget(nodeid, nlookup uint64) {
}
}
+*/
func (b *rawBridge) SetDebug(debug bool) {}
diff --git a/nodefs/default.go b/nodefs/default.go
index 56fcb4e..7fef8a1 100644
--- a/nodefs/default.go
+++ b/nodefs/default.go
@@ -6,22 +6,47 @@
package nodefs
// DefaultNode provides common base Node functionality.
//
// It must be embedded in any Node implementation.
type DefaultNode struct {
- inode *Inode
-}
-
-func (dn *DefaultNode) setInode(n *Inode) {
- dn.inode = n
-}
-
-func (dn *DefaultNode) Inode() *Inode {
- return dn.inode
+ inode_ *Inode
+}
+
+// set/retrieve inode.
+//
+// node -> inode association, can be simultaneously tried to be set, if for e.g.
+//
+// root
+// / \
+// dir1 dir2
+// \ /
+// file
+//
+// dir1.Lookup("file") and dir2.Lookup("file") are executed simultaneously.
+//
+// We use atomics so that only one set can win and rawBridge.Lookup cares to
+// cancel inode that loosed.
+//
+// To read node.inode atomic.LoadPointer is used, however it is not expensive
+// since it translates to regular MOVQ on amd64.
+
+func (dn *DefaultNode) setInode(inode *Inode) bool {
+ return atomic.CompareAndSwapPointer(
+ (*unsafe.Pointer)(unsafe.Pointer(&dn.inode_)),
+ nil, unsafe.Pointer(inode))
+}
+
+func (dn *DefaultNode) inode() *Inode {
+ return (*Inode)(atomic.LoadPointer(
+ (*unsafe.Pointer)(unsafe.Pointer(&dn.inode_))))
}
func (n *DefaultNode) Read(ctx context.Context, f File, dest []byte, off int64) (fuse.ReadResult, fuse.Status) {
diff --git a/nodefs/inode.go b/nodefs/inode.go
index 2f14b9d..4f3ebbb 100644
--- a/nodefs/inode.go
+++ b/nodefs/inode.go
@@ -34,38 +34,93 @@
type Inode struct {
// Following data is mutable.
- // Protected by bridge.mu
- nodeID uint64
-
// mu protects the following mutable fields. When locking
// multiple Inodes, locks must be acquired using
// lockNodes/unlockNodes
mu sync.Mutex
// changeCounter increments every time the below mutable state
// (lookupCount, nodeID, children, parents) is modified.
//
// This is used in places where we have to relock inode into inode
// group lock, and after locking the group we have to check if inode
// did not changed, and if it changed - retry the operation.
changeCounter uint32
lookupCount uint64
+
+ // ID of the inode; 0 if inode was forgotten.
+ // forgotten inodes are unlinked from parent and children, but could be
+ // still not yet removed from bridge.nodes .
+ nodeID uint64
+
children map[string]*Inode
parents map[parentData]struct{}
}
+// newInode creates creates new inode pointing to node.
+//
+// node -> inode association is NOT set.
+// the inode is _not_ yet has
+func newInode(node Node, mode uint32) *Inode {
+ inode := &Inode{
+ mode: mode ^ 07777,
+ node: node,
+ //bridge: n.bridge,
+ parents: make(map[parentData]struct{}),
+ }
+ if mode&fuse.S_IFDIR != 0 {
+ inode.children = make(map[string]*Inode)
+ }
+ //node.setInode(ch)
+ return inode
+}
+
// sortNodes rearranges inode group in consistent order.
//
// The nodes are ordered by their in-RAM address, which gives consistency
@@ -74,9 +129,14 @@
func unlockNodes(ns ...*Inode) {
// kernel has no way of reviving forgotten nodes by its own
// initiative.
func (n *Inode) Forgotten() bool {
+ /*
n.bridge.mu.Lock()
defer n.bridge.mu.Unlock()
return n.lookupCount == 0
+ */
+ n.mu.Lock()
+ defer n.mu.Unlock()
+ return n.nodeID == 0
}
// Node returns the Node object implementing the file system operations.
diff --git a/nodefs/simple_test.go b/nodefs/simple_test.go
index df0e09c..5e2dc46 100644
--- a/nodefs/simple_test.go
+++ b/nodefs/simple_test.go
@@ -6,10 +6,10 @@
package nodefs
import (
"bytes"
- "io"
"io/ioutil"
"os"
"path/filepath"
+ "runtime"
"testing"
"time"
nodefs/api.go
View file @
bedd3b65
...
...
@@ -36,6 +36,9 @@
// automatically builds new index node and links it in the filesystem tree.
// InodeOf can be used to get particular Inode associated with a Node.
//
// XXX once can also create new subtrees via linking nodes explicitly, and
// return such subtree on lookup.
//
// XXX ^^^ inodes cleaned on cache clean (FORGET).
//
// XXX describe how to mount.
...
...
@@ -57,8 +60,11 @@ import (
//
// The identity of the Inode does not change over the lifetime of
// the node object.
//
// Returned Inode is always !nil - if node was not yet associated with inode, a
// new inode is atomically created and associated with the node.
func
InodeOf
(
node
Node
)
*
Inode
{
return
node
.
inode
(
)
return
inodeOf
(
node
)
}
/*
...
...
@@ -81,21 +87,32 @@ type Node interface {
inode
()
*
Inode
setInode
(
*
Inode
)
// NodeID() should return filesystem-wide ID of the node.
//
// If the node has such ID it will be used as the base for corresponding inode ID.
// If the node does not have such ID - 0 must be returned and
// automatically allocated inode ID will be used.
//
// The ID, if given, must be unique throughout filesystem.
//
// XXX range of allowed ID = ?
NodeID
()
uint64
// Lookup should find a direct child of the node by child name.
//
// VFS makes sure to call Lookup only once for particular (node, name)
// pair.
Lookup
(
ctx
context
.
Context
,
name
string
,
out
*
fuse
.
EntryOut
)
(
*
In
ode
,
fuse
.
Status
)
Lookup
(
ctx
context
.
Context
,
name
string
,
out
*
fuse
.
EntryOut
)
(
N
ode
,
fuse
.
Status
)
Mkdir
(
ctx
context
.
Context
,
name
string
,
mode
uint32
,
out
*
fuse
.
EntryOut
)
(
*
In
ode
,
fuse
.
Status
)
Mknod
(
ctx
context
.
Context
,
name
string
,
mode
uint32
,
dev
uint32
,
out
*
fuse
.
EntryOut
)
(
*
In
ode
,
fuse
.
Status
)
Mkdir
(
ctx
context
.
Context
,
name
string
,
mode
uint32
,
out
*
fuse
.
EntryOut
)
(
N
ode
,
fuse
.
Status
)
Mknod
(
ctx
context
.
Context
,
name
string
,
mode
uint32
,
dev
uint32
,
out
*
fuse
.
EntryOut
)
(
N
ode
,
fuse
.
Status
)
Rmdir
(
ctx
context
.
Context
,
name
string
)
fuse
.
Status
Unlink
(
ctx
context
.
Context
,
name
string
)
fuse
.
Status
Rename
(
ctx
context
.
Context
,
name
string
,
newParent
Node
,
newName
string
,
flags
uint32
)
fuse
.
Status
Open
(
ctx
context
.
Context
,
flags
uint32
)
(
fh
File
,
fuseFlags
uint32
,
code
fuse
.
Status
)
Create
(
ctx
context
.
Context
,
name
string
,
flags
uint32
,
mode
uint32
)
(
node
*
In
ode
,
fh
File
,
fuseFlags
uint32
,
code
fuse
.
Status
)
Create
(
ctx
context
.
Context
,
name
string
,
flags
uint32
,
mode
uint32
)
(
node
N
ode
,
fh
File
,
fuseFlags
uint32
,
code
fuse
.
Status
)
Read
(
ctx
context
.
Context
,
f
File
,
dest
[]
byte
,
off
int64
)
(
fuse
.
ReadResult
,
fuse
.
Status
)
...
...
@@ -137,6 +154,7 @@ type Node interface {
Allocate
(
ctx
context
.
Context
,
f
File
,
off
uint64
,
size
uint64
,
mode
uint32
)
(
code
fuse
.
Status
)
}
// XXX -> Handle? FileHandle? (better Handle as handle could be used not only for leaves)
type
File
interface
{
Read
(
ctx
context
.
Context
,
dest
[]
byte
,
off
int64
)
(
fuse
.
ReadResult
,
fuse
.
Status
)
Write
(
ctx
context
.
Context
,
data
[]
byte
,
off
int64
)
(
written
uint32
,
code
fuse
.
Status
)
...
...
nodefs/bridge.go
View file @
bedd3b65
...
...
@@ -20,6 +20,7 @@ type fileEntry struct {
// space to hold directory stuff
}
// rawBridge interconnects nodefs tree structure with raw FUSE exchange.
type
rawBridge
struct
{
fuse
.
RawFileSystem
...
...
@@ -36,7 +37,7 @@ type rawBridge struct {
freeFiles
[]
uint64
}
// newInode creates
creates
new inode pointing to node.
// newInode creates new inode pointing to node.
// XXX - should store the Ino number we expose in GetAttr too ?
func
(
b
*
rawBridge
)
newInode
(
node
Node
,
mode
uint32
,
id
FileID
,
persistent
bool
)
*
Inode
{
b
.
mu
.
Lock
()
...
...
@@ -46,6 +47,8 @@ func (b *rawBridge) newInode(node Node, mode uint32, id FileID, persistent bool)
log
.
Panicf
(
"using reserved ID %d for inode number"
,
id
.
Ino
)
}
// FIXME with automatic IDs this can create 2 inodes for 1 node if
// there are 2 concurrent lookups via different paths.
if
id
.
Ino
==
0
{
id
.
Ino
=
b
.
automaticIno
b
.
automaticIno
++
...
...
@@ -153,7 +156,6 @@ func (b *rawBridge) Rmdir(header *fuse.InHeader, name string) fuse.Status {
parent
.
RmChild
(
name
)
}
return
code
}
func
(
b
*
rawBridge
)
Unlink
(
header
*
fuse
.
InHeader
,
name
string
)
fuse
.
Status
{
...
...
@@ -425,6 +427,9 @@ func (b *rawBridge) Open(input *fuse.OpenIn, out *fuse.OpenOut) (status fuse.Sta
//
// XXX is it allowed to return the same Fh from two different Open
// calls on the same inode?
// XXX -> absolutely no, 2 different opens should result in 2 diffrerent Fh.
// an example when not doing so would break badly is e.g. socket-like file-handles,
// where IO on different handle is completey separate from the rest.
func
(
b
*
rawBridge
)
registerFile
(
f
File
)
uint64
{
var
fh
uint64
if
len
(
b
.
freeFiles
)
>
0
{
...
...
nodefs/default.go
View file @
bedd3b65
...
...
@@ -18,6 +18,10 @@ type DefaultNode struct {
inode_
*
Inode
}
// XXX why we dropped atomics here?
// -> moved rawBridge.newInode() ?
// text: "set/retrieve inode" in na1.patch
func
(
dn
*
DefaultNode
)
setInode
(
inode
*
Inode
)
{
dn
.
inode_
=
inode
}
...
...
@@ -26,6 +30,12 @@ func (dn *DefaultNode) inode() *Inode {
return
dn
.
inode_
}
func
inodeOf
(
node
Node
)
*
Inode
{
// XXX .inode = nil -> atomically create new
// XXX requires that we move atomic stuff back to setInode/inode/inodeOf
return
node
.
inode
()
}
func
(
n
*
DefaultNode
)
Read
(
ctx
context
.
Context
,
f
File
,
dest
[]
byte
,
off
int64
)
(
fuse
.
ReadResult
,
fuse
.
Status
)
{
if
f
!=
nil
{
return
f
.
Read
(
ctx
,
dest
,
off
)
...
...
nodefs/inode.go
View file @
bedd3b65
...
...
@@ -37,7 +37,7 @@ type FileID struct {
Gen
uint64
}
//
Zero returns if the FileID is zeroed out
//
Reserved returns if the FileID is reserved and should not be used ... XXX
func
(
i
*
FileID
)
Reserved
()
bool
{
return
i
.
Ino
==
0
||
i
.
Ino
==
1
||
i
.
Ino
==
^
uint64
(
0
)
}
...
...
@@ -117,11 +117,12 @@ func nodeLess(a, b *Inode) bool {
// It also avoids locking an inode more than once, if it was specified multiple times.
// An example when an inode might be given multiple times is if dir/a and dir/b
// are hardlinked to the same inode and the caller needs to take locks on dir children.
//
// It is valid to give nil nodes - those are simply ignored.
func
lockNodes
(
ns
...*
Inode
)
{
sortNodes
(
ns
)
// The default value nil prevents trying to lock nil nodes.
var
nprev
*
Inode
var
nprev
*
Inode
=
nil
// initial nil + sort/dedup makes us ignore nil nodes
for
_
,
n
:=
range
ns
{
if
n
!=
nprev
{
n
.
mu
.
Lock
()
...
...
@@ -133,22 +134,30 @@ func lockNodes(ns ...*Inode) {
// lockNode2 locks a and b in order consistent with lockNodes.
func
lockNode2
(
a
,
b
*
Inode
)
{
if
a
==
b
{
b
=
nil
}
if
!
nodeLess
(
a
,
b
)
{
b
,
a
=
a
,
b
}
if
a
!=
nil
{
a
.
mu
.
Lock
()
}
else
if
nodeLess
(
a
,
b
)
{
a
.
mu
.
Lock
()
b
.
mu
.
Lock
()
}
else
{
}
if
b
!=
nil
{
b
.
mu
.
Lock
()
a
.
mu
.
Lock
()
}
}
// unlockNode2 unlocks a and b
// unlockNode2 unlocks a and b
loced by lockNode2.
func
unlockNode2
(
a
,
b
*
Inode
)
{
if
a
==
b
{
b
=
nil
}
// there is no deadlock if we unlock nodes in different compared to
// order they were locked.
if
a
!=
nil
{
a
.
mu
.
Unlock
()
}
else
{
a
.
mu
.
Unlock
()
}
if
b
!=
nil
{
b
.
mu
.
Unlock
()
}
}
...
...
@@ -159,7 +168,7 @@ func unlockNodes(ns ...*Inode) {
// however it still helps to have nodes sorted to avoid duplicates.
sortNodes
(
ns
)
var
nprev
*
Inode
var
nprev
*
Inode
=
nil
// initial nil + sort/dedup makes us ignore nil nodes
for
_
,
n
:=
range
ns
{
if
n
!=
nprev
{
n
.
mu
.
Unlock
()
...
...
@@ -351,7 +360,7 @@ retry:
// RmChild removes multiple children. Returns whether the removal
// succeeded and whether the node is still live afterward. The removal
// is transactional: it only succeeds if all names are children, and
// is transactional: it only succeeds if all names are
in
children, and
// if they all were removed successfully. If the removal was
// successful, and there are no children left, the node may be removed
// from the FS tree. In that case, RmChild returns live==false.
...
...
nodefs/loopback.go
View file @
bedd3b65
...
...
@@ -62,7 +62,7 @@ func (n *loopbackNode) path() string {
return
filepath
.
Join
(
n
.
rootNode
.
root
,
path
)
}
func
(
n
*
loopbackNode
)
Lookup
(
ctx
context
.
Context
,
name
string
,
out
*
fuse
.
EntryOut
)
(
*
In
ode
,
fuse
.
Status
)
{
func
(
n
*
loopbackNode
)
Lookup
(
ctx
context
.
Context
,
name
string
,
out
*
fuse
.
EntryOut
)
(
N
ode
,
fuse
.
Status
)
{
p
:=
filepath
.
Join
(
n
.
path
(),
name
)
st
:=
syscall
.
Stat_t
{}
...
...
@@ -73,11 +73,12 @@ func (n *loopbackNode) Lookup(ctx context.Context, name string, out *fuse.EntryO
out
.
Attr
.
FromStat
(
&
st
)
node
:=
n
.
rootNode
.
newLoopbackNode
()
ch
:=
n
.
inode
()
.
NewInode
(
node
,
out
.
Attr
.
Mode
,
idFromStat
(
&
st
))
return
ch
,
fuse
.
OK
return
node
,
fuse
.
OK
//ch := n.inode().NewInode(node, out.Attr.Mode, idFromStat(&st))
//return ch, fuse.OK
}
func
(
n
*
loopbackNode
)
Mknod
(
ctx
context
.
Context
,
name
string
,
mode
,
rdev
uint32
,
out
*
fuse
.
EntryOut
)
(
*
In
ode
,
fuse
.
Status
)
{
func
(
n
*
loopbackNode
)
Mknod
(
ctx
context
.
Context
,
name
string
,
mode
,
rdev
uint32
,
out
*
fuse
.
EntryOut
)
(
N
ode
,
fuse
.
Status
)
{
p
:=
filepath
.
Join
(
n
.
path
(),
name
)
err
:=
syscall
.
Mknod
(
p
,
mode
,
int
(
rdev
))
if
err
!=
nil
{
...
...
@@ -92,9 +93,10 @@ func (n *loopbackNode) Mknod(ctx context.Context, name string, mode, rdev uint32
out
.
Attr
.
FromStat
(
&
st
)
node
:=
n
.
rootNode
.
newLoopbackNode
()
ch
:=
n
.
inode
()
.
NewInode
(
node
,
out
.
Attr
.
Mode
,
idFromStat
(
&
st
))
return
node
,
fuse
.
OK
return
ch
,
fuse
.
OK
//ch := n.inode().NewInode(node, out.Attr.Mode, idFromStat(&st))
//return ch, fuse.OK
}
func
(
n
*
loopbackNode
)
Mkdir
(
ctx
context
.
Context
,
name
string
,
mode
uint32
,
out
*
fuse
.
EntryOut
)
(
*
Inode
,
fuse
.
Status
)
{
...
...
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