{"record":{"id":"d460df4a15cd0288","repo":"VictoriaMetrics/VictoriaMetrics","slug":"cannot-open-q-for-preallocation-w","errorCode":null,"errorMessage":"cannot open %q for preallocation: %w","messagePattern":"cannot open %q for preallocation: %w","errorType":"exception","errorClass":null,"httpStatus":null,"severity":"error","filePath":"lib/backup/fslocal/prealloc_linux.go","lineNumber":17,"sourceCode":"package fslocal\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"syscall\"\n)\n\nconst canPreallocate = true\n\nfunc preallocateFile(path string, size int64) error {\n\tif size <= 0 {\n\t\treturn nil\n\t}\n\tf, err := os.OpenFile(path, os.O_WRONLY|os.O_CREATE, 0600)\n\tif err != nil {\n\t\treturn fmt.Errorf(\"cannot open %q for preallocation: %w\", path, err)\n\t}\n\terr = syscall.Fallocate(int(f.Fd()), 0, 0, size)\n\tif err1 := f.Close(); err1 != nil && err == nil {\n\t\terr = err1\n\t}\n\tif err != nil {\n\t\treturn fmt.Errorf(\"cannot fallocate %d bytes for %q: %w\", size, path, err)\n\t}\n\treturn nil\n}\n","sourceCodeStart":1,"sourceCodeEnd":28,"githubUrl":"https://github.com/VictoriaMetrics/VictoriaMetrics/blob/5079fb58f1e8e62113f90c945ad71586c797d770/lib/backup/fslocal/prealloc_linux.go#L1-L28","documentation":"Fires in the Linux preallocateFile when os.OpenFile cannot open the target path (O_WRONLY|O_CREATE) prior to fallocate. Input at fault is the part file path; wrapped error is an open failure — missing parent directory, permissions, or a read-only filesystem.","triggerScenarios":"Thrown at lib/backup/fslocal/prealloc_linux.go:17 when the library encounters an invalid state.","commonSituations":"See trigger scenarios.","solutions":["Ensure the parent directory exists and is writable","Check filesystem is mounted read-write","Disable preallocation (SkipPreallocation) as a workaround on unsupported filesystems"],"exampleFix":null,"handlingStrategy":"fallback","validationCode":null,"typeGuard":null,"tryCatchPattern":null,"preventionTips":[],"tags":[],"backgroundTag":null,"analyzedSha":"5079fb58f1e8e62113f90c945ad71586c797d770","analyzedAt":"2026-09-03T18:10:26.153Z","contentChangedAt":"2026-09-03T18:10:26.153Z","schemaVersion":2},"datasetVersion":"2026-09-08T15:18:49.778Z"}