[PATCH 0/7] Allow lock dropping before waiting on inodes being freed

[Andreas Gruenbacher <agruenba@redhat.com>]

This patch set my Bob and me avoids a deadlock in gfs2 when an inode is being
freed: normally, when find_inode finds an inode in I_FREEING or I_WILL_FREE
state, it waits for the inode to go away before returning
(__wait_on_freeing_inode).  Freeing an inode on gfs2 requires taking the
inode's glock.  However, in gfs2_lookup_by_inum, we need to be holding the
inode glock while doing lookups, so we can deadlock with processes concurrently
freeing inodes.

This patch set allows gfs2_lookup_by_inum to drop the inode glock before
waiting for inodes to go away.  We could try non-blocking lookups and wait for
an arbitrary amount of time before retrying the lookup instead as well, but
waiting for the actual event (i.e., the inode being freed to likely have
disappeared) makes more sense.

Thanks,
Andreas

Andreas Gruenbacher (5):
  GFS2: Remove superfluous assignment
  GFS2: No need for non-blocking gfs2_ilookup in delete_work_func
  vfs: Introduce prepare_wait_on_freeing_inode
  GFS2: Use non-blocking wait in gfs2_iget
  GFS2: Prevent deadlock in gfs2_lookup_by_inum

Bob Peterson (2):
  Revert "GFS2: Eliminate parameter non_block on gfs2_inode_lookup"
  Revert "GFS2: Don't filter out I_FREEING inodes anymore"

 fs/gfs2/dir.c        |   2 +-
 fs/gfs2/glock.c      |   4 +-
 fs/gfs2/inode.c      | 109 ++++++++++++++++++++++++++++++++++++++++++++++-----
 fs/gfs2/inode.h      |   8 +++-
 fs/gfs2/ops_fstype.c |   2 +-
 fs/inode.c           |  18 +++++++--
 include/linux/fs.h   |   1 +
 include/linux/wait.h |  21 +++++++---
 8 files changed, 142 insertions(+), 23 deletions(-)

-- 
2.5.5