• Anton Altaparmakov's avatar
    NTFS: Fix a mount time deadlock. · bfab36e8
    Anton Altaparmakov authored
    
    
    Big thanks go to Mathias Kolehmainen for reporting the bug, providing
    debug output and testing the patches I sent him to get it working.
    
    The fix was to stop calling ntfs_attr_set() at mount time as that causes
    balance_dirty_pages_ratelimited() to be called which on systems with
    little memory actually tries to go and balance the dirty pages which tries
    to take the s_umount semaphore but because we are still in fill_super()
    across which the VFS holds s_umount for writing this results in a
    deadlock.
    
    We now do the dirty work by hand by submitting individual buffers.  This
    has the annoying "feature" that mounting can take a few seconds if the
    journal is large as we have clear it all.  One day someone should improve
    on this by deferring the journal clearing to a helper kernel thread so it
    can be done in the background but I don't have time for this at the moment
    and the current solution works fine so I am leaving it like this for now.
    Signed-off-by: default avatarAnton Altaparmakov <aia21@cantab.net>
    Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
    bfab36e8
inode.c 97 KB