__fpending - Linux

Overview

The __fpending command is a Linux system administration tool that provides information about pending file system operations. It is primarily used to identify and manage file system operations that are queued or in progress, allowing administrators to monitor and troubleshoot potential performance issues.

Syntax

__fpending [options] [mountpoint]

Options/Flags

  • -c, –columns: Customizes the output columns displayed. Available columns include: file, pid, command, state, time, deadline, and mountpoint.
  • -i, –inclusive: Includes child processes in the output.
  • -n, –numeric: Displays process IDs (PIDs) numerically instead of resolving them to process names.
  • -s, –sort: Sorts the output by the specified column. Valid sort keys include: file, pid, state, and time.
  • -t, –timeout: Specifies a timeout limit (in seconds) for pending operations. Defaults to 0 (indefinite).

Examples

  • List pending file system operations for the /home mountpoint:
__fpending /home
  • Display only the file path and process ID (PID) of pending operations:
__fpending -c file,pid
  • Sort output by the pending operation’s file path:
__fpending -s file
  • Include child processes in the output and specify a timeout of 5 seconds:
__fpending -i -t 5

Common Issues

  • Invalid mountpoint: Ensure the specified mountpoint is valid and accessible.
  • No output: No pending file system operations are currently active.
  • Excessive waiting times: Investigate the process with the highest pending time using ps or top commands.

Integration

  • Use __fpending with find to identify files that are currently being accessed:
find /path -xdev -mount -exec __fpending -c file {} +
  • Combine with watch to monitor pending operations in real-time:
watch __fpending

Related Commands

  • fuser: Lists processes accessing files or directories.
  • lsof: Lists open files and processes using them.
  • ps: Displays running processes and their state.