mirror of
https://github.com/zrepl/zrepl.git
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286 lines
8.4 KiB
Go
286 lines
8.4 KiB
Go
package zfs
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import (
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"context"
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"fmt"
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"os/exec"
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"regexp"
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"strconv"
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"strings"
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"sync"
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"time"
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"github.com/pkg/errors"
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"github.com/zrepl/zrepl/util/envconst"
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"github.com/zrepl/zrepl/zfs/zfscmd"
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)
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// NOTE: Update ZFSSendARgs.Validate when changing fields (potentially SECURITY SENSITIVE)
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type ResumeToken struct {
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HasFromGUID, HasToGUID bool
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FromGUID, ToGUID uint64
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ToName string
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HasCompressOK, CompressOK bool
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HasRawOk, RawOK bool
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}
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var resumeTokenNVListRE = regexp.MustCompile(`\t(\S+) = (.*)`)
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var resumeTokenContentsRE = regexp.MustCompile(`resume token contents:\nnvlist version: 0`)
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var resumeTokenIsCorruptRE = regexp.MustCompile(`resume token is corrupt`)
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var ResumeTokenCorruptError = errors.New("resume token is corrupt")
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var ResumeTokenDecodingNotSupported = errors.New("zfs binary does not allow decoding resume token or zrepl cannot scrape zfs output")
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var ResumeTokenParsingError = errors.New("zrepl cannot parse resume token values")
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var resumeSendSupportedCheck struct {
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once sync.Once
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supported bool
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err error
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}
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func ResumeSendSupported(ctx context.Context) (bool, error) {
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resumeSendSupportedCheck.once.Do(func() {
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// "feature discovery"
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cmd := zfscmd.CommandContext(ctx, "zfs", "send")
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output, err := cmd.CombinedOutput()
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if ee, ok := err.(*exec.ExitError); !ok || ok && !ee.Exited() {
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resumeSendSupportedCheck.err = errors.Wrap(err, "resumable send cli support feature check failed")
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}
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def := strings.Contains(string(output), "receive_resume_token")
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resumeSendSupportedCheck.supported = envconst.Bool("ZREPL_EXPERIMENTAL_ZFS_SEND_RESUME_SUPPORTED", def)
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debug("resume send feature check complete %#v", &resumeSendSupportedCheck)
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})
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return resumeSendSupportedCheck.supported, resumeSendSupportedCheck.err
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}
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var resumeRecvPoolSupportRecheckTimeout = envconst.Duration("ZREPL_ZFS_RESUME_RECV_POOL_SUPPORT_RECHECK_TIMEOUT", 30*time.Second)
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type resumeRecvPoolSupportedResult struct {
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lastCheck time.Time
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supported bool
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err error
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}
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var resumeRecvSupportedCheck struct {
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mtx sync.RWMutex
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flagSupport struct {
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checked bool
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supported bool
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err error
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}
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poolSupported map[string]resumeRecvPoolSupportedResult
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}
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// fs == nil only checks for CLI support
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func ResumeRecvSupported(ctx context.Context, fs *DatasetPath) (bool, error) {
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sup := &resumeRecvSupportedCheck
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sup.mtx.RLock()
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defer sup.mtx.RUnlock()
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upgradeWhile := func(cb func()) {
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sup.mtx.RUnlock()
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defer sup.mtx.RLock()
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sup.mtx.Lock()
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defer sup.mtx.Unlock()
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cb()
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}
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if !sup.flagSupport.checked {
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output, err := zfscmd.CommandContext(ctx, ZFS_BINARY, "receive").CombinedOutput()
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upgradeWhile(func() {
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sup.flagSupport.checked = true
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if ee, ok := err.(*exec.ExitError); err != nil && (!ok || ok && !ee.Exited()) {
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sup.flagSupport.err = err
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} else {
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sup.flagSupport.supported = strings.Contains(string(output), "-A <filesystem|volume>")
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}
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debug("resume recv cli flag feature check result: %#v", sup.flagSupport)
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})
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// fallthrough
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}
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if sup.flagSupport.err != nil {
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return false, errors.Wrap(sup.flagSupport.err, "zfs recv feature check for resumable send & recv failed")
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} else if !sup.flagSupport.supported || fs == nil {
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return sup.flagSupport.supported, nil
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}
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// Flag is supported and pool-support is request
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// Now check for pool support
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pool, err := fs.Pool()
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if err != nil {
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return false, errors.Wrap(err, "resume recv check requires pool of dataset")
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}
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if sup.poolSupported == nil {
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upgradeWhile(func() {
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sup.poolSupported = make(map[string]resumeRecvPoolSupportedResult)
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})
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}
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var poolSup resumeRecvPoolSupportedResult
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var ok bool
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if poolSup, ok = sup.poolSupported[pool]; !ok || // shadow
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(!poolSup.supported && time.Since(poolSup.lastCheck) > resumeRecvPoolSupportRecheckTimeout) {
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output, err := zfscmd.CommandContext(ctx, "zpool", "get", "-H", "-p", "-o", "value", "feature@extensible_dataset", pool).CombinedOutput()
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if err != nil {
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debug("resume recv pool support check result: %#v", sup.flagSupport)
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poolSup.supported = false
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poolSup.err = err
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} else {
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poolSup.err = nil
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o := strings.TrimSpace(string(output))
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poolSup.supported = o == "active" || o == "enabled"
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}
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poolSup.lastCheck = time.Now()
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// we take the lock late, so two updaters might check simultaneously, but that shouldn't hurt
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upgradeWhile(func() {
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sup.poolSupported[pool] = poolSup
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})
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// fallthrough
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}
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if poolSup.err != nil {
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return false, errors.Wrapf(poolSup.err, "pool %q check for feature@extensible_dataset feature failed", pool)
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}
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return poolSup.supported, nil
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}
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// Abuse 'zfs send' to decode the resume token
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//
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// FIXME: implement nvlist unpacking in Go and read through libzfs_sendrecv.c
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func ParseResumeToken(ctx context.Context, token string) (*ResumeToken, error) {
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if supported, err := ResumeSendSupported(ctx); err != nil {
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return nil, err
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} else if !supported {
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return nil, ResumeTokenDecodingNotSupported
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}
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// Example resume tokens:
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//
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// From a non-incremental send
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// 1-bf31b879a-b8-789c636064000310a500c4ec50360710e72765a5269740f80cd8e4d3d28a534b18e00024cf86249f5459925acc802a8facbf243fbd3433858161f5ddb9ab1ae7c7466a20c97382e5f312735319180af2f3730cf58166953824c2cc0200cde81651
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// From an incremental send
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// 1-c49b979a2-e0-789c636064000310a501c49c50360710a715e5e7a69766a63040c1eabb735735ce8f8d5400b2d991d4e52765a5269740f82080219f96569c5ac2000720793624f9a4ca92d46206547964fd25f91057f09e37babb88c9bf5503499e132c9f97989bcac050909f9f63a80f34abc421096616007c881d4c
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// Resulting output of zfs send -nvt <token>
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//
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//resume token contents:
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//nvlist version: 0
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// fromguid = 0x595d9f81aa9dddab
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// object = 0x1
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// offset = 0x0
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// bytes = 0x0
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// toguid = 0x854f02a2dd32cf0d
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// toname = pool1/test@b
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//cannot resume send: 'pool1/test@b' used in the initial send no longer exists
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cmd := zfscmd.CommandContext(ctx, ZFS_BINARY, "send", "-nvt", string(token))
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output, err := cmd.CombinedOutput()
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if err != nil {
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if exitErr, ok := err.(*exec.ExitError); ok {
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if !exitErr.Exited() {
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return nil, err
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}
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// we abuse zfs send for decoding, the exit error may be due to
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// a) the token being from a third machine
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// b) it no longer exists on the machine where
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} else {
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return nil, err
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}
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}
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if !resumeTokenContentsRE.Match(output) {
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if resumeTokenIsCorruptRE.Match(output) {
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return nil, ResumeTokenCorruptError
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}
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return nil, ResumeTokenDecodingNotSupported
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}
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matches := resumeTokenNVListRE.FindAllStringSubmatch(string(output), -1)
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if matches == nil {
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return nil, ResumeTokenDecodingNotSupported
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}
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rt := &ResumeToken{}
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for _, m := range matches {
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attr, val := m[1], m[2]
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switch attr {
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case "fromguid":
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rt.FromGUID, err = strconv.ParseUint(val, 0, 64)
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if err != nil {
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return nil, ResumeTokenParsingError
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}
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rt.HasFromGUID = true
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case "toguid":
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rt.ToGUID, err = strconv.ParseUint(val, 0, 64)
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if err != nil {
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return nil, ResumeTokenParsingError
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}
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rt.HasToGUID = true
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case "toname":
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rt.ToName = val
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case "rawok":
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rt.HasRawOk = true
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rt.RawOK, err = strconv.ParseBool(val)
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if err != nil {
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return nil, ResumeTokenParsingError
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}
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case "compressok":
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rt.HasCompressOK = true
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rt.CompressOK, err = strconv.ParseBool(val)
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if err != nil {
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return nil, ResumeTokenParsingError
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}
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}
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}
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if !rt.HasToGUID {
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return nil, ResumeTokenDecodingNotSupported
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}
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return rt, nil
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}
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// if string is empty and err == nil, the feature is not supported
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func ZFSGetReceiveResumeTokenOrEmptyStringIfNotSupported(ctx context.Context, fs *DatasetPath) (string, error) {
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if supported, err := ResumeRecvSupported(ctx, fs); err != nil {
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return "", errors.Wrap(err, "cannot determine zfs recv resume support")
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} else if !supported {
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return "", nil
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}
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const prop_receive_resume_token = "receive_resume_token"
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props, err := ZFSGet(ctx, fs, []string{prop_receive_resume_token})
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if err != nil {
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return "", err
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}
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res := props.Get(prop_receive_resume_token)
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debug("%q receive_resume_token=%q", fs.ToString(), res)
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if res == "-" {
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return "", nil
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} else {
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return res, nil
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}
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}
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func (t *ResumeToken) ToNameSplit() (fs *DatasetPath, snapName string, err error) {
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comps := strings.SplitN(t.ToName, "@", 2)
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if len(comps) != 2 {
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return nil, "", fmt.Errorf("resume token field `toname` does not contain @: %q", t.ToName)
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}
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dp, err := NewDatasetPath(comps[0])
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if err != nil {
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return nil, "", errors.Wrap(err, "resume token field `toname` dataset path invalid")
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}
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return dp, comps[1], nil
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}
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