src/patches/suse-2.6.27.31/patches.fixes/ocfs2-1.4-git-4e8a301929bfa017e6ffe11e3cf78ccaf8492801

   1 From: Jan Kara <jack@suse.cz>
   2 Subject: ocfs2: Fix possible deadlock in ocfs2_global_read_dquot()
   3 Patch-mainline: 2.6.31
   4
   5 It is not possible to get a read lock and then try to get the same write lock
   6 in one thread as that can block on downconvert being requested by other node
   7 leading to deadlock. So first drop the quota lock for reading and only after
   8 that get it for writing.
   9
  10 Signed-off-by: Jan Kara <jack@suse.cz>
  11 ---
  12  fs/ocfs2/quota_global.c |    4 +++-
  13  1 file changed, 3 insertions(+), 1 deletion(-)
  14
  15 --- a/fs/ocfs2/quota_global.c
  16 +++ b/fs/ocfs2/quota_global.c
  17 @@ -354,6 +354,7 @@ int ocfs2_global_read_dquot(struct dquot
  18         OCFS2_DQUOT(dquot)->dq_originodes = dquot->dq_dqb.dqb_curinodes;
  19         if (!dquot->dq_off) {   /* No real quota entry? */
  20                 /* Upgrade to exclusive lock for allocation */
  21 +               ocfs2_qinfo_unlock(info, 0);
  22                 err = ocfs2_qinfo_lock(info, 1);
  23                 if (err < 0)
  24                         goto out_qlock;
  25 @@ -368,7 +369,8 @@ int ocfs2_global_read_dquot(struct dquot
  26  out_qlock:
  27         if (ex)
  28                 ocfs2_qinfo_unlock(info, 1);
  29 -       ocfs2_qinfo_unlock(info, 0);
  30 +       else
  31 +               ocfs2_qinfo_unlock(info, 0);
  32  out:
  33         if (err < 0)
  34                 mlog_errno(err);