btrfs-snapshots-diff

About

btrfs-snapshots-diff.py is a simple Python2 script that displays the differences between two Btrfs snapshots (from the same subvolume obviously).

Uses btrfs send to compute the differences, decodes the stream and displays the differences.

Can read data from parent and current snapshots, or from diff file created with:

btrfs send -p parent chid --no-data -f /tmp/snaps-diff

Usage

usage: btrfs-snapshots-diff.py [-h] [-p PARENT] [-c CHILD] [-f FILE] [-t] [-a] [-s] [-j] [-b]

Display differences between 2 Btrfs snapshots

optional arguments: -h, --help show this help message and exit -p PARENT, --parent PARENT parent snapshot (must exists and be readonly) -c CHILD, --child CHILD child snapshot (will be created if it does not exist) -f FILE, --file FILE diff file -t, --filter does not display temporary files, nor all time modifications (just latest) -a, --by_path Group commands by path -s, --csv CSV output -j, --json JSON output (commands only) -b, --bogus Add bogus renamed_from action (used only when grouping by path)

Option --json (-j), available for commands only, will output a list of commands in JSON format.

Option --csv (-s) will produce on line for each modification, instead of formatted output: the first column is the path, then each action taken on the file is in a new column. Separator is ";".

Option --by_path (-a) groups command by path, giving a better view of what happenned on the file system.

--bogus (-b) adds a bogus command to the stream, to better track renaming of files / dir (only usefull with --by_path).

With option --filter (-t), the script tries to be a bit smarter (only usefull with --by_path):

• it does not display temporary files created by send stream,
• it displays 'created' or 'rewritten' on the files renamed from temporary files,
• it displays only the latest time modifications, if there are two or more.

Example

The example below is the result of creating a new subvolume, taking a snapshot (parent), creating some objects ( a file called "file", a directory called "dir", fifo, link and symlink...), then taking a new snapshot, and last calling btrfs-snapshots-diff to display the differences (see test.sh).

sudo ./btrfs-snapshots-diff.py -p btrfs-diff-tests.parent -c btrfs-diff-tests.child
Found a valid Btrfs stream header, version 1

btrfs-diff-tests.child
	snapshot: uuid=d6515a0a57d462449bcc9c2533d01277, ctrasid=171948, clone_uuid=b66a4f902e348b46b87d4cb85d967ad9, clone_ctransid=171945

__sub_root__
	times a=2016/04/03 10:36:13 m=2016/04/03 10:36:15 c=2016/04/03 10:36:15
	times a=2016/04/03 10:36:13 m=2016/04/03 10:36:15 c=2016/04/03 10:36:15
	times a=2016/04/03 10:36:13 m=2016/04/03 10:36:15 c=2016/04/03 10:36:15
	times a=2016/04/03 10:36:13 m=2016/04/03 10:36:15 c=2016/04/03 10:36:15
	times a=2016/04/03 10:36:13 m=2016/04/03 10:36:15 c=2016/04/03 10:36:15
	times a=2016/04/03 10:36:13 m=2016/04/03 10:36:15 c=2016/04/03 10:36:15

o257-171948-0
	mkfile
	rename to "file"

file
	renamed from "o257-171948-0"
	xattr security.selinux 28277
	truncate 0
	owner 1000:1000
	mode 664
	times a=2016/04/03 10:36:15 m=2016/04/03 10:36:15 c=2016/04/03 10:36:15

hardlink
	link to "file"

o258-171948-0
	mkdir
	rename to "dir"

dir
	renamed from "o258-171948-0"
	xattr security.selinux 28277
	owner 1000:1000
	mode 775
	times a=2016/04/03 10:36:15 m=2016/04/03 10:36:15 c=2016/04/03 10:36:15

o259-171948-0
	mkfifo
	rename to "fifo"

fifo
	renamed from "o259-171948-0"
	xattr security.selinux 28277
	owner 1000:1000
	mode 664
	times a=2016/04/03 10:36:15 m=2016/04/03 10:36:15 c=2016/04/03 10:36:15

o260-171948-0
	symlink to "file"
	rename to "symlink"

symlink
	renamed from "o260-171948-0"
	xattr security.selinux 28277
	owner 1000:1000
	times a=2016/04/03 10:36:15 m=2016/04/03 10:36:15 c=2016/04/03 10:36:15

Requirements

No requirements besides Python-3!

Bugs

There are probably bugs, though it works for me on my own snapshots.

License

GPL v2, see LICENSE file.

Made in beautiful Tahiti (French Polynesia) by SysNux.

Copyright (c) 2016 Jean-Denis Girard jd.girard@sysnux.pf