Okajima,
I see that aufs 2.2 just prints the warning and continues.
What are the effects of this cache inconsistency ie., inode of aufs isn't
consistent with inode of branch. When would aufs again sync with branch's
inode? What happens if someone deletes the file directly on branch? Does it
mean that aufs thinks that file is there (because it wasn't notified) but file
is gone from underneath? Sounds like "ubda=notify" is a must-have option so
aufs works correctly. Please correct me if I'm wrong.
thank you.
/* successful returns with iinfo write_locked */
/* todo: return with unlocked? */
struct inode *au_new_inode(struct dentry *dentry, int must_new)
{
:
}
if (unlikely(au_test_fs_unique_ino(h_dentry->d_inode)))
AuWarn1("Warning: Un-notified UDBA or repeatedly renamed dir,"
" b%d, %s, %.*s, hi%lu, i%lu.\n",
bstart, au_sbtype(h_dentry->d_sb), AuDLNPair(dentry),
(unsigned long)h_ino, (unsigned long)ino);
ino = 0;
err = au_xino_write(sb, bstart, h_ino, /*ino*/0);
if (!err) {
________________________________
From: "sf...@users.sourceforge.net" <sf...@users.sourceforge.net>
To: Prasad Koya <kdp...@yahoo.com>
Cc: "aufs-users@lists.sourceforge.net" <aufs-users@lists.sourceforge.net>
Sent: Tuesday, October 16, 2012 7:04 PM
Subject: Re: aufs Warning: Un-notified UDBA
Hello Prasad,
Prasad Koya:
> aufs au_new_inode:412:Aaa[7803]: Warning: Un-notified UDBA or repeatedly
> renamed dir, b0, tmpfs, admin, hi5959, i4117.
> We are seeing above warning from aufs. Two questions:
>
> 1. Is above message benign? Or does it indicate there is some memory leak or
> something of that sort happening?
>
> 2. Pl see my mounts below. I tried running a command like "mv /.overlay/test
> /.overlay/test1; mv /.overlay/test1 /.overlay/test" like several 10s of
> thousand times but I didn't see above warning. Any other way I can find out
> what is it from user space or kernel space that is making aufs throw this
> warning?
The message doesn't indicate a memory leak. It tells you that
- you have accessed a file in aufs, and the system stores its inode in cache.
- you made some changes to the file outside of aufs (bypassing aufs).
- you access the file again in aufs.
- aufs finds something unmatched between the cached aufs-inode and the
inode on the branch fs (directly changed inode), and produces the
warning.
To reproduce the warning, I'd suggest you the following steps. But I am
not sure it can surely reproduce since it highly depends upon the cache
situation.
- /u = /rw + /ro
- run "> /u/file" once
- repeat "stat /u/file > /dev/null" in background
- repeat "> /rw/file2; mv /rw/file2 /rw/file"
If you want aufs to support such situation without the warning, then you
should use the aufs "udba=notify" mount option. It detects the direct
changes on the branch and aufs simply make the cached inode obsolete.
If you didn't make any direct changes, then there may be something wrong
in aufs. Please let me know more details.
J. R. Okajima
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