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"All filesystems are equal, but some filesystems are more equal than others."

"All filesystems are equal, but some filesystems are more equal than others."

This page describes how different different filesystems are and how this affects CRIU dump (and restore) process.

This page describes how different filesystems affect the CRIU dump (and restore) process.

== BTRFS ==

== BTRFS ==

== AUFS ==

== AUFS ==

AUFS is not (yet) upstream, but Docker guys use one, so does CRIU.

[http://aufs.sourceforge.net AUFS] is not (yet) upstream, but Docker guys use one, so does CRIU.

AUFS has a strange BUG -- when we <code>execv</code> some file on it, and then check for <code>/proc/$pid/maps</code> or <code>.../smaps</code> files or links in the <code>.../map_files/</code> directory, we would note, that those mappings, that correspond to the executed file are seen under "wrong" paths.

This FS has a strange BUG -- when we <code>execv</code> some file on it, and then check for <code>/proc/$pid/maps</code> or <code>.../smaps</code> files or links in the <code>.../map_files/</code> directory, we would note, that those mappings, that correspond to the executed file are seen under "wrong" paths.

How wrong are these paths? AUFS joins several subdirectories into one, all these subdirs are called ''branches''. And the file seen inside AUFS by one path "really" has some other one -- the path by the file is seen in the respective branch. So in proc in these strange cases we would see the path from branch, instead of the path, by which the file is seen in AUFS.

How wrong are these paths? AUFS joins several subdirectories into one, all these subdirs are called ''branches''. And the file seen inside AUFS by one path "really" has some other one -- the path by the file is seen in the respective branch. So in proc in these strange cases we would see the path from branch, instead of the path, by which the file is seen in AUFS.

[[Category:Under the hood]]

[[Category:Under the hood]]