hyperledger/fabric · critical

Could not open writer to current file: %s

Error message

Could not open writer to current file: %s

What it means

Panic when newBlockfileWriter cannot open (create/append) the current block file (blockfile_<latestFileNumber>) for the ledger. Without the writer, new blocks cannot be appended and block storage init fails.

Source

Thrown at common/ledger/blkstorage/blockfile_mgr.go:125

	}
	if blockfilesInfo == nil {
		logger.Info(`Getting block information from block storage`)
		if blockfilesInfo, err = constructBlockfilesInfo(rootDir); err != nil {
			panic(fmt.Sprintf("Could not build blockfilesInfo info from block files: %s", err))
		}
		logger.Debugf("Info constructed by scanning the blocks dir = %s", spew.Sdump(blockfilesInfo))
	} else {
		logger.Debug(`Syncing block information from block storage (if needed)`)
		syncBlockfilesInfoFromFS(rootDir, blockfilesInfo)
	}
	err = mgr.saveBlkfilesInfo(blockfilesInfo, true)
	if err != nil {
		panic(fmt.Sprintf("Could not save next block file info to db: %s", err))
	}

	currentFileWriter, err := newBlockfileWriter(deriveBlockfilePath(rootDir, blockfilesInfo.latestFileNumber))
	if err != nil {
		panic(fmt.Sprintf("Could not open writer to current file: %s", err))
	}
	err = currentFileWriter.truncateFile(blockfilesInfo.latestFileSize)
	if err != nil {
		panic(fmt.Sprintf("Could not truncate current file to known size in db: %s", err))
	}
	if mgr.index, err = newBlockIndex(indexConfig, indexStore); err != nil {
		panic(fmt.Sprintf("error in block index: %s", err))
	}

	mgr.blockfilesInfo = blockfilesInfo
	bsi, err := loadBootstrappingSnapshotInfo(rootDir)
	if err != nil {
		return nil, err
	}
	mgr.bootstrappingSnapshotInfo = bsi
	mgr.currentFileWriter = currentFileWriter
	mgr.blkfilesInfoCond = sync.NewCond(&sync.Mutex{})

View on GitHub (pinned to 2736b63f8f)

Solutions

1. Grant the peer user write permission on the ledger's chains dir (chown/chmod)
2. Mount the ledger volume read-write and check free disk space
3. If the path is wrong (config pointing at wrong dir), fix core.yaml fileLedger settings

Example fix

// before: running peer as non-root on root-owned data
// after:
// sudo chown -R peer:peer /var/hyperledger/production/ledgersData && systemctl start peer

currentPath := deriveBlockfilePath(rootDir, latestFileNumber)
f, err := os.OpenFile(currentPath, os.O_RDWR|os.O_CREATE, 0o644)
if err != nil {
    return fmt.Errorf("cannot open current block file %s: %w", currentPath, err)
}
f.Close()

defer func() {
    if r := recover(); r != nil {
        err = fmt.Errorf("block file writer init failed: %v", r)
    }
}()

When it happens

Trigger: newBlockfileWriter returns an error opening deriveBlockfilePath(rootDir, latestFileNumber): permission denied, read-only fs, I/O error, or invalid path during newBlockfileMgr.

Common situations: chains/<ledgerID> dir not writable by the peer; read-only mounted volume; disk/device failure; wrong user after container image change or migration.

Understand the failure class

Background: "open() failed", "failed to open file", "cannot create file" — what a file open error means and how to fix it — this error's family across 42 libraries.

Related errors

• Error creating block storage root dir [%s]: %s
• Initialization of chaincode store failed: %s
• Could not create _lifecycle chaincodes install path: %s
• error retrieving file info for file number %d
• error while reading bootstrappingSnapshotInfo file

AI-assisted analysis of hyperledger/fabric@2736b63f8f (2026-09-04). Data as JSON: /api/errors/e8e39c2be4cbda82. Report an issue: GitHub.