From 1bee43be13549b01e18d87df194ac219845de5cf Mon Sep 17 00:00:00 2001 From: Fabricio Voznika Date: Thu, 9 May 2019 15:34:44 -0700 Subject: Implement fallocate(2) Closes #225 PiperOrigin-RevId: 247508791 Change-Id: I04f47cf2770b30043e5a272aba4ba6e11d0476cc --- pkg/p9/BUILD | 1 + pkg/p9/client_file.go | 12 ++++++ pkg/p9/file.go | 4 ++ pkg/p9/handlers.go | 34 ++++++++++++++++ pkg/p9/local_server/local_server.go | 5 +++ pkg/p9/messages.go | 59 +++++++++++++++++++++++++++ pkg/p9/p9.go | 81 +++++++++++++++++++++++++++++++++++++ pkg/p9/version.go | 7 +++- 8 files changed, 202 insertions(+), 1 deletion(-) (limited to 'pkg/p9') diff --git a/pkg/p9/BUILD b/pkg/p9/BUILD index 5d972309d..36b2ec5f6 100644 --- a/pkg/p9/BUILD +++ b/pkg/p9/BUILD @@ -26,6 +26,7 @@ go_library( "//pkg/fd", "//pkg/log", "//pkg/unet", + "@org_golang_x_sys//unix:go_default_library", ], ) diff --git a/pkg/p9/client_file.go b/pkg/p9/client_file.go index 63c65129a..471c3a80b 100644 --- a/pkg/p9/client_file.go +++ b/pkg/p9/client_file.go @@ -171,6 +171,18 @@ func (c *clientFile) SetAttr(valid SetAttrMask, attr SetAttr) error { return c.client.sendRecv(&Tsetattr{FID: c.fid, Valid: valid, SetAttr: attr}, &Rsetattr{}) } +// Allocate implements File.Allocate. +func (c *clientFile) Allocate(mode AllocateMode, offset, length uint64) error { + if atomic.LoadUint32(&c.closed) != 0 { + return syscall.EBADF + } + if !versionSupportsTallocate(c.client.version) { + return syscall.EOPNOTSUPP + } + + return c.client.sendRecv(&Tallocate{FID: c.fid, Mode: mode, Offset: offset, Length: length}, &Rallocate{}) +} + // Remove implements File.Remove. // // N.B. This method is no longer part of the file interface and should be diff --git a/pkg/p9/file.go b/pkg/p9/file.go index a52a0f3e7..89e814d50 100644 --- a/pkg/p9/file.go +++ b/pkg/p9/file.go @@ -89,6 +89,10 @@ type File interface { // On the server, SetAttr has a write concurrency guarantee. SetAttr(valid SetAttrMask, attr SetAttr) error + // Allocate allows the caller to directly manipulate the allocated disk space + // for the file. See fallocate(2) for more details. + Allocate(mode AllocateMode, offset, length uint64) error + // Close is called when all references are dropped on the server side, // and Close should be called by the client to drop all references. // diff --git a/pkg/p9/handlers.go b/pkg/p9/handlers.go index 6da2ce4e3..533ead98a 100644 --- a/pkg/p9/handlers.go +++ b/pkg/p9/handlers.go @@ -877,6 +877,40 @@ func (t *Tsetattr) handle(cs *connState) message { return &Rsetattr{} } +// handle implements handler.handle. +func (t *Tallocate) handle(cs *connState) message { + // Lookup the FID. + ref, ok := cs.LookupFID(t.FID) + if !ok { + return newErr(syscall.EBADF) + } + defer ref.DecRef() + + if err := ref.safelyWrite(func() error { + // Has it been opened already? + openFlags, opened := ref.OpenFlags() + if !opened { + return syscall.EINVAL + } + + // Can it be written? Check permissions. + if openFlags&OpenFlagsModeMask == ReadOnly { + return syscall.EBADF + } + + // We don't allow allocate on files that have been deleted. + if ref.isDeleted() { + return syscall.EINVAL + } + + return ref.file.Allocate(t.Mode, t.Offset, t.Length) + }); err != nil { + return newErr(err) + } + + return &Rallocate{} +} + // handle implements handler.handle. func (t *Txattrwalk) handle(cs *connState) message { // Lookup the FID. diff --git a/pkg/p9/local_server/local_server.go b/pkg/p9/local_server/local_server.go index f4077a9d4..d49d94550 100644 --- a/pkg/p9/local_server/local_server.go +++ b/pkg/p9/local_server/local_server.go @@ -323,6 +323,11 @@ func (l *local) Renamed(parent p9.File, newName string) { l.path = path.Join(parent.(*local).path, newName) } +// Allocate implements p9.File.Allocate. +func (l *local) Allocate(mode p9.AllocateMode, offset, length uint64) error { + return syscall.Fallocate(int(l.file.Fd()), mode.ToLinux(), int64(offset), int64(length)) +} + func main() { log.SetLevel(log.Debug) diff --git a/pkg/p9/messages.go b/pkg/p9/messages.go index 3c7898cc1..703753c31 100644 --- a/pkg/p9/messages.go +++ b/pkg/p9/messages.go @@ -1424,6 +1424,63 @@ func (r *Rsetattr) String() string { return fmt.Sprintf("Rsetattr{}") } +// Tallocate is an allocate request. This is an extension to 9P protocol, not +// present in the 9P2000.L standard. +type Tallocate struct { + FID FID + Mode AllocateMode + Offset uint64 + Length uint64 +} + +// Decode implements encoder.Decode. +func (t *Tallocate) Decode(b *buffer) { + t.FID = b.ReadFID() + t.Mode.Decode(b) + t.Offset = b.Read64() + t.Length = b.Read64() +} + +// Encode implements encoder.Encode. +func (t *Tallocate) Encode(b *buffer) { + b.WriteFID(t.FID) + t.Mode.Encode(b) + b.Write64(t.Offset) + b.Write64(t.Length) +} + +// Type implements message.Type. +func (*Tallocate) Type() MsgType { + return MsgTallocate +} + +// String implements fmt.Stringer. +func (t *Tallocate) String() string { + return fmt.Sprintf("Tallocate{FID: %d, Offset: %d, Length: %d}", t.FID, t.Offset, t.Length) +} + +// Rallocate is an allocate response. +type Rallocate struct { +} + +// Decode implements encoder.Decode. +func (*Rallocate) Decode(b *buffer) { +} + +// Encode implements encoder.Encode. +func (*Rallocate) Encode(b *buffer) { +} + +// Type implements message.Type. +func (*Rallocate) Type() MsgType { + return MsgRallocate +} + +// String implements fmt.Stringer. +func (r *Rallocate) String() string { + return fmt.Sprintf("Rallocate{}") +} + // Txattrwalk walks extended attributes. type Txattrwalk struct { // FID is the FID to check for attributes. @@ -2297,4 +2354,6 @@ func init() { msgRegistry.register(MsgRusymlink, func() message { return &Rusymlink{} }) msgRegistry.register(MsgTlconnect, func() message { return &Tlconnect{} }) msgRegistry.register(MsgRlconnect, func() message { return &Rlconnect{} }) + msgRegistry.register(MsgTallocate, func() message { return &Tallocate{} }) + msgRegistry.register(MsgRallocate, func() message { return &Rallocate{} }) } diff --git a/pkg/p9/p9.go b/pkg/p9/p9.go index 78c7d3f86..4039862e6 100644 --- a/pkg/p9/p9.go +++ b/pkg/p9/p9.go @@ -22,6 +22,8 @@ import ( "strings" "sync/atomic" "syscall" + + "golang.org/x/sys/unix" ) // OpenFlags is the mode passed to Open and Create operations. @@ -374,6 +376,8 @@ const ( MsgRusymlink = 135 MsgTlconnect = 136 MsgRlconnect = 137 + MsgTallocate = 138 + MsgRallocate = 139 ) // QIDType represents the file type for QIDs. @@ -1058,3 +1062,80 @@ func (d *Dirent) Encode(b *buffer) { b.WriteQIDType(d.Type) b.WriteString(d.Name) } + +// AllocateMode are possible modes to p9.File.Allocate(). +type AllocateMode struct { + KeepSize bool + PunchHole bool + NoHideStale bool + CollapseRange bool + ZeroRange bool + InsertRange bool + Unshare bool +} + +// ToLinux converts to a value compatible with fallocate(2)'s mode. +func (a *AllocateMode) ToLinux() uint32 { + rv := uint32(0) + if a.KeepSize { + rv |= unix.FALLOC_FL_KEEP_SIZE + } + if a.PunchHole { + rv |= unix.FALLOC_FL_PUNCH_HOLE + } + if a.NoHideStale { + rv |= unix.FALLOC_FL_NO_HIDE_STALE + } + if a.CollapseRange { + rv |= unix.FALLOC_FL_COLLAPSE_RANGE + } + if a.ZeroRange { + rv |= unix.FALLOC_FL_ZERO_RANGE + } + if a.InsertRange { + rv |= unix.FALLOC_FL_INSERT_RANGE + } + if a.Unshare { + rv |= unix.FALLOC_FL_UNSHARE_RANGE + } + return rv +} + +// Decode implements encoder.Decode. +func (a *AllocateMode) Decode(b *buffer) { + mask := b.Read32() + a.KeepSize = mask&0x01 != 0 + a.PunchHole = mask&0x02 != 0 + a.NoHideStale = mask&0x04 != 0 + a.CollapseRange = mask&0x08 != 0 + a.ZeroRange = mask&0x10 != 0 + a.InsertRange = mask&0x20 != 0 + a.Unshare = mask&0x40 != 0 +} + +// Encode implements encoder.Encode. +func (a *AllocateMode) Encode(b *buffer) { + mask := uint32(0) + if a.KeepSize { + mask |= 0x01 + } + if a.PunchHole { + mask |= 0x02 + } + if a.NoHideStale { + mask |= 0x04 + } + if a.CollapseRange { + mask |= 0x08 + } + if a.ZeroRange { + mask |= 0x10 + } + if a.InsertRange { + mask |= 0x20 + } + if a.Unshare { + mask |= 0x40 + } + b.Write32(mask) +} diff --git a/pkg/p9/version.go b/pkg/p9/version.go index a36a499a1..c2a2885ae 100644 --- a/pkg/p9/version.go +++ b/pkg/p9/version.go @@ -26,7 +26,7 @@ const ( // // Clients are expected to start requesting this version number and // to continuously decrement it until a Tversion request succeeds. - highestSupportedVersion uint32 = 6 + highestSupportedVersion uint32 = 7 // lowestSupportedVersion is the lowest supported version X in a // version string of the format 9P2000.L.Google.X. @@ -143,3 +143,8 @@ func VersionSupportsAnonymous(v uint32) bool { func VersionSupportsMultiUser(v uint32) bool { return v >= 6 } + +// versionSupportsTallocate returns true if version v supports Allocate(). +func versionSupportsTallocate(v uint32) bool { + return v >= 7 +} -- cgit v1.2.3