1. 15 Nov, 2010 1 commit
    • Steven Whitehouse's avatar
      GFS2: Fix inode deallocation race · 044b9414
      Steven Whitehouse authored
      
      
      This area of the code has always been a bit delicate due to the
      subtleties of lock ordering. The problem is that for "normal"
      alloc/dealloc, we always grab the inode locks first and the rgrp lock
      later.
      
      In order to ensure no races in looking up the unlinked, but still
      allocated inodes, we need to hold the rgrp lock when we do the lookup,
      which means that we can't take the inode glock.
      
      The solution is to borrow the technique already used by NFS to solve
      what is essentially the same problem (given an inode number, look up
      the inode carefully, checking that it really is in the expected
      state).
      
      We cannot do that directly from the allocation code (lock ordering
      again) so we give the job to the pre-existing delete workqueue and
      carry on with the allocation as normal.
      
      If we find there is no space, we do a journal flush (required anyway
      if space from a deallocation is to be released) which should block
      against the pending deallocations, so we should always get the space
      back.
      Signed-off-by: default avatarSteven Whitehouse <swhiteho@redhat.com>
      044b9414
  2. 13 Nov, 2010 6 commits
  3. 12 Nov, 2010 33 commits