{"record":{"id":"256d9b69ae705b54","repo":"hyperledger/fabric","slug":"error-opening-block-file-reader-for-file-s","errorCode":null,"errorMessage":"error opening block file reader for file %s","messagePattern":"error opening block file reader for file (.+?)","errorType":"exception","errorClass":null,"httpStatus":null,"severity":"error","filePath":"common/ledger/blkstorage/blockfile_rw.go","lineNumber":73,"sourceCode":"\t\treturn err\n\t}\n\tw.file = file\n\treturn nil\n}\n\nfunc (w *blockfileWriter) close() error {\n\treturn errors.WithStack(w.file.Close())\n}\n\n// //  READER ////\ntype blockfileReader struct {\n\tfile *os.File\n}\n\nfunc newBlockfileReader(filePath string) (*blockfileReader, error) {\n\tfile, err := os.OpenFile(filePath, os.O_RDONLY, 0o600)\n\tif err != nil {\n\t\treturn nil, errors.Wrapf(err, \"error opening block file reader for file %s\", filePath)\n\t}\n\treader := &blockfileReader{file}\n\treturn reader, nil\n}\n\nfunc (r *blockfileReader) read(offset int, length int) ([]byte, error) {\n\tb := make([]byte, length)\n\t_, err := r.file.ReadAt(b, int64(offset))\n\tif err != nil {\n\t\treturn nil, errors.Wrapf(err, \"error reading block file for offset %d and length %d\", offset, length)\n\t}\n\treturn b, nil\n}\n\nfunc (r *blockfileReader) close() error {\n\treturn errors.WithStack(r.file.Close())\n}\n","sourceCodeStart":55,"sourceCodeEnd":91,"githubUrl":"https://github.com/hyperledger/fabric/blob/2736b63f8fd5932511d56fe68b7039d15977f7f6/common/ledger/blkstorage/blockfile_rw.go#L55-L91","documentation":"newBlockfileReader wraps errors from os.OpenFile(filePath, O_RDONLY, 0o600) when opening an existing block file for reading. It is returned to callers like fetchRawBytes when a block/transaction is retrieved from the file-based block store. The wrapped OS error gives the actual cause.","triggerScenarios":"Calling GetBlockByNumber/GetTransactionById etc. (leading to fetchRawBytes -> newBlockfileReader) when the blockfile_XXXXXX file is missing, unreadable due to permissions, or the path refers to something that is not a regular file.","commonSituations":"Ledger data directory partially deleted or restored from an incomplete backup; files copied between hosts with wrong ownership/permissions; block file removed while peer was down; NFS/volume mount issues; attempting to query a channel whose ledger files were pruned.","solutions":["Inspect the wrapped cause: 'no such file' means the blockfile is missing; 'permission denied' means fix file ownership/mode.","Restore the missing/corrupted ledger files from a known-good backup of ledgersData taken while the peer was stopped.","Fix permissions: chown/chmod the blockfile and its directory so the peer process user can read them (files are 0o600).","If the ledger is irrecoverable, drop the channel data (peer channel join again / remove ledgersData for that channel) and re-sync from the ordering service or a snapshot."],"exampleFix":"// before: blockfile copied by root with restrictive perms, peer runs as 'peer'\n// ERROR: error opening block file reader for file .../blockfile_000000: open ...: permission denied\n// after (shell):\nchown -R peer:peer /var/hyperledger/production/ledgersData\nchmod -R u+rwX /var/hyperledger/production/ledgersData","handlingStrategy":"try-catch","validationCode":"// Go: verify the block file exists and is readable before querying the ledger\nfunc blockFileReadable(chainsDir, channel string, num uint64) error {\n\tp := filepath.Join(chainsDir, \"chains\", channel, fmt.Sprintf(\"blockfile_%06d\", num))\n\tf, err := os.Open(p)\n\tif err != nil {\n\t\treturn err\n\t}\n\treturn f.Close()\n}","typeGuard":null,"tryCatchPattern":"// Go: distinguish missing vs permission vs other when reading via the store\nblock, err := store.RetrieveBlockByNumber(blkNum)\nif err != nil {\n\tswitch c := errors.Cause(err).(type) {\n\tcase *fs.PathError:\n\t\tif os.IsNotExist(c) {\n\t\t\t// ledger file missing: restore from backup or resync\n\t\t}\n\t\tif os.IsPermission(c) {\n\t\t\t// fix ownership/mode\n\t\t}\n\tdefault:\n\t\treturn err\n\t}\n}","preventionTips":["Take backups only while the peer is stopped; never copy ledgersData live.","Preserve ownership/modes when restoring backups (rsync -a, tar -p).","Do not delete or prune blockfile_* files manually.","Use consistent storage (local disk or reliable PV) rather than flaky network mounts."],"tags":["filesystem","io","ledger","permissions"],"backgroundTag":"file-open-failed","analyzedSha":"2736b63f8fd5932511d56fe68b7039d15977f7f6","analyzedAt":"2026-09-04T08:52:36.465Z","contentChangedAt":"2026-09-04T08:52:36.465Z","schemaVersion":2},"datasetVersion":"2026-09-08T05:18:18.240Z"}