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#Linux file system reader and writer windows 10 update#

# process A: lock the file and subtract 20įlock -verbose balance.dat. We create a simple shell script a.sh to simulate process A: #!/bin/bash #sleep 10 seconds to simulate business calculationĮcho -n -e "\033[77DCalculating new balance.$progress%"Įcho "Write new balance ($value) back to $file."

#Linux file system reader and writer windows 10 update#

We first create a simple shell script update_balance.sh to handle balance update logic for both processes: #!/bin/bash In this example row, the entire file is locked.

This column, together with the last one, shows the start and end of the locked region of the file being locked.

This field contains a colon-separated-values string, showing the id of the locked file in the format of “ major-device:minor-device:inode“.

Then we have the ID of the process holding the lock.

The fourth field reveals if the lock is a WRITE or READ lock.

It can have two values: ADVISORY or MANDATORY.

The second field indicates the class of the lock used, such as FLOCK (from flock system call) or POSIX (from the lockf, fcntl system call).

Let’s pick the first row to understand how the lock information is organized in the /proc/locks file system: 1: FLOCK ADVISORY WRITE 369159 08:12:22417368 0 EOF

The lslocks command relies on this file to generate the list, too. Instead, it is a file in the procfs virtual file system.