• Ryusuke Konishi's avatar
    nilfs2: fix gc failure on volumes keeping numerous snapshots · b028fcfc
    Ryusuke Konishi authored
    This resolves the following failure of nilfs2 cleaner daemon:
    
     nilfs_cleanerd[20670]: cannot clean segments: No such file or directory
     nilfs_cleanerd[20670]: shutdown
    
    When creating thousands of snapshots, the cleaner daemon had rarely died
    as above due to an error returned from the kernel code.
    
    After applying the recent patch which fixed memory allocation problems in
    ioctl (Message-Id: <20081215.155840.105124170.ryusuke@osrg.net>), the
    problem gets more frequent.
    
    It turned out to be a bug of nilfs_ioctl_wrap_copy function and one of its
    callback routines to read out information of snapshots; if the
    nilfs_ioctl_wrap_copy function divided a large read request into multiple
    requests, the second and later requests have failed since a restart
    position on snapshot meta data was not properly set forward.
    
    It's a deficiency of the callback interface that cannot pass the restart
    position among multiple requests.  This patch fixes the issue by allowing
    nilfs_ioctl_wrap_copy and snapshot read functions to exchange a position
    argument.
    Signed-off-by: default avatarRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
    Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
    b028fcfc
ioctl.c 25.1 KB