#19564: after reboot - reset to defaults / firstboot by accident
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Reporter: bittorf@… | Owner: developers
Type: defect | Status: new
Priority: highest | Milestone:
Component: packages | Version: Trunk
Resolution: | Keywords:
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Comment (by hnyman):
"upper" is the overlaying r/w part, so I think that it needs to be in the
writable jffs2 part. And "work" needs to be in the same filesystem.
Your two questions are nice ;-)
Some thoughts:
- Log contains three error messages. Two are from Openwrt fstools, but the
deepest one is from overlayfs itself. The error is not actually the
missing /overlay/work, but that subdirectory /overlay/work/work can't be
created.
- The discussion at Linux file systems discussion group indicates that
similar error may surface when the upper filesystem that should be r/w is
actually r/o. http://thread.gmane.org/gmane.linux.file-
systems/91881/focus=175
- As far as I understand, overlayfs may return that error if the
filesystem is read-only or creating a real directory inside the working
dir fails.
https://git.kernel.org/cgit/linux/kernel/git/stable/linux-
stable.git/tree/fs/overlayfs/super.c#n925
https://git.kernel.org/cgit/linux/kernel/git/stable/linux-
stable.git/tree/fs/overlayfs/super.c#n635
https://git.kernel.org/cgit/linux/kernel/git/stable/linux-
stable.git/tree/fs/overlayfs/dir.c#n72
- Is it possible that the filesystem is somehow recognised as r/o if there
are no free blocks at boot? Or something similar?
- Linux 3.18.x introduced multi-level lower layers in overlayfs, and that
may be the change that has triggered this behaviour in Openwrt in the last
few weeks.
- The changes done between Linux 3.18.11 and .12 may clarify the
situation, as the overlayfs error messages have been tweaked a bit in
March. But .12 has not yet been imported into Openwrt, so we are still
running .11 (if at 3.18 like ar71xx). Commits below:
https://git.kernel.org/cgit/linux/kernel/git/stable/linux-
stable.git/log/fs/overlayfs
https://git.kernel.org/cgit/linux/kernel/git/stable/linux-
stable.git/commit/fs/overlayfs?id=71cbad7e694ee81233b3be3a38b81c3d5872cc6f
In any case, this sounds like something coming from rather deep in Linux.
It might not be directly related to Openwrt, but might be a "feature" in
Linux overlayfs itself :-(
--
Ticket URL: <https://dev.openwrt.org/ticket/19564#comment:12>
OpenWrt <http://openwrt.org>
Opensource Wireless Router Technology
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