Why do two different CIFS clients show different values of inodes for the same files?

Solution Verified - Updated -

Environment

  • Red Hat Enterprise Linux 6
  • Red Hat Enterprise Linux 7
  • Red Hat Enterprise Linux 8
  • CIFS client

Issue

  • Why do two different CIFS clients show different values of inodes for the same files?

  • Below messages are observed during issue:

    CIFS VFS: Autodisabling the use of server inode numbers on [share].
CIFS VFS: The server doesn't seem to support them properly or the files might be on different servers (DFS).
CIFS VFS: Hardlinks will not be recognized on this mount. Consider mounting with the "noserverino" option to silence this message.

Resolution

  • These messages indicate that the CIFS server does not support returning inode numbers or the CIFS client detects an inode collision. Then the CIFS client enables noserverino option, and will generate unique ids as inode numbers.
  • Check with the CIFS server vendor why returning inode numbers are not supported or inode numbers are duplicated.
  • Workaround option 1: Remount the share to enable serverino option again.
  • Workaround option 2: Mount the share with the noserverino option to prevent the messages.

Root Cause

  • The serverino option is disabled and noserverino is enabled because the CIFS server does not support returning inode numbers or the CIFS client detects an inode collision, and an unique ids which is generated temporary on the client side will be used as inode numbers.

  • For more details of the options, please refer to MOUNT.CIFS(8):

           serverino
              Use  inode numbers (unique persistent file identifiers) returned
              by the server  instead  of  automatically  generating  temporary
              inode  numbers on the client. Although server inode numbers make
              it easier to spot hardlinked files (as they will have  the  same
              inode  numbers)  and  inode  numbers may be persistent (which is
              useful for some software), the server does  not  guarantee  that
              the  inode numbers are unique if multiple server side mounts are
              exported under a  single  share  (since  inode  numbers  on  the
              servers  might not be unique if multiple filesystems are mounted
              under the same shared higher level directory). Note that not all
              servers  support  returning server inode numbers, although those
              that support the CIFS Unix  Extensions,  and  Windows  2000  and
              later  servers typically do support this (although not necessar‐
              ily on every local server filesystem). Parameter has  no  effect
              if  the  server  lacks  support  for  returning inode numbers or
              equivalent. This behavior is enabled by default.

       noserverino
              Client generates inode numbers  itself  rather  than  using  the
              actual ones from the server.

              See section INODE NUMBERS for more information.

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