upstream report. https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=881239 possible bug in VFS aio_linux Package: samba Version: 2:4.7.0+dfsg-2 Severity: normal Running config: [global] netbios name = CPO1007DEB workgroup = WORKGROUP server string = CPO1007DEB Samba Staging VM wins server = xx.xx.xx.xx dns proxy = no domain master = no local master = no preferred master = no max log size = 0 log level = 10 syslog = 0 panic action = /usr/share/samba/panic-action %d debug prefix timestamp = yes security = user guest account = nobody map to guest = Bad User printing = bsd printcap name = /dev/null load printers = no show add printer wizard = no hide dot files = no veto files = /Thumbs.db/*.shs/*.lnk/Desktop.ini/.*/ deadtime = 15 keepalive = 960 create mask = 0664 force create mode = 0664 directory mask = 0775 force directory mode = 0775 force user = nobody force group = nogroup nt acl support = no usershare max shares = 0 kernel oplocks = no kernel share modes = no posix locking = no socket options = IPTOS_LOWDELAY TCP_NODELAY use sendfile = yes aio read size = 4096 aio write size = 4096 vfs objects = aio_linux [USER-RW] comment = User Read-Write path = /srv/smb/user-rw browseable = yes read only = yes guest ok = no valid users = snowman write list = snowman [GUEST-RO] comment = Guest Read-Only path = /srv/smb/guest-ro browseable = yes read only = yes guest ok = yes guest only = yes
WONTFIX might sound harsh, but the fix is not to ship aio_linux in debian. Linux AIO is not suiteable for samba's file access requirements. It only works on O_DIRECT for page-aligned accesses, something Samba does not do. The fix is to just say "aio write size = 1" and "aio read size = 1" without any vfs objects. This activates the threaded implementation for async I/O that is implemented in core Samba. Please transfer this info to the debian package maintainer (if you are not the one yourself :-) and close the debian bug with the same statement. Please remove aio_linux from the debian package. Thanks, Volker
Thank you for the reply Volker, i've updated the debian bug report with you tekst. Best regards, Louis
@Volker: But it looks like a regression. Why was is working before?
It might have not crashed, but it definitely did not do what it promised to do: Do *asynchronous* I/O. The Linux API falls back to sync behaviour when not all the prerequisites are fulfilled, which is *always* the case for Samba. So yes, technically this might be a regression. But you're far better off disabling AIO completely and removing this module from your conf. This has exactly the same effect. I am not willing to spend my spare time on a module that silently does not do what it promises to do. If you need that nevertheless, feel free to submit a patch. Alternatively, please contact someone from https://www.samba.org/samba/support and pay to fix the module. I the meantime I've sent around a patch to remove this thing from Samba.
(In reply to Mathieu Parent from comment #3) > @Volker: But it looks like a regression. Why was is working before? Just FYI: Since https://git.samba.org/?p=samba.git;a=commitdiff;h=6381044c0270a647c20935d the aio_linux VFS module is gone.