10 May, 2011

2 commits


24 Feb, 2011

1 commit

  • Michael Leun reported that running parallel opens on a fuse filesystem
    can trigger a "kernel BUG at mm/truncate.c:475"

    Gurudas Pai reported the same bug on NFS.

    The reason is, unmap_mapping_range() is not prepared for more than
    one concurrent invocation per inode. For example:

    thread1: going through a big range, stops in the middle of a vma and
    stores the restart address in vm_truncate_count.

    thread2: comes in with a small (e.g. single page) unmap request on
    the same vma, somewhere before restart_address, finds that the
    vma was already unmapped up to the restart address and happily
    returns without doing anything.

    Another scenario would be two big unmap requests, both having to
    restart the unmapping and each one setting vm_truncate_count to its
    own value. This could go on forever without any of them being able to
    finish.

    Truncate and hole punching already serialize with i_mutex. Other
    callers of unmap_mapping_range() do not, and it's difficult to get
    i_mutex protection for all callers. In particular ->d_revalidate(),
    which calls invalidate_inode_pages2_range() in fuse, may be called
    with or without i_mutex.

    This patch adds a new mutex to 'struct address_space' to prevent
    running multiple concurrent unmap_mapping_range() on the same mapping.

    [ We'll hopefully get rid of all this with the upcoming mm
    preemptibility series by Peter Zijlstra, the "mm: Remove i_mmap_mutex
    lockbreak" patch in particular. But that is for 2.6.39 ]

    Signed-off-by: Miklos Szeredi
    Reported-by: Michael Leun
    Reported-by: Gurudas Pai
    Tested-by: Gurudas Pai
    Acked-by: Hugh Dickins
    Cc: stable@kernel.org
    Signed-off-by: Linus Torvalds

    Miklos Szeredi
     

23 Jul, 2010

1 commit

  • This adds mode argument to nilfs_btnode_submit_block() function and
    allows it to issue a read-ahead request.

    An optional submit_ptr argument is also added to store the actual
    block address for which bio is sent. submit_ptr is used for a series
    of read-ahead requests, and helps to decide if each requested block is
    continous to the previous one on disk.

    Signed-off-by: Ryusuke Konishi

    Ryusuke Konishi
     

20 Nov, 2009

3 commits


10 Jun, 2009

1 commit


07 Apr, 2009

1 commit