src/patches/suse-2.6.27.31/patches.fixes/block-get-rid-of-the-manual-directory-counting-in-blktrace.patch

   1 From: Jens Axboe <jens.axboe@oracle.com>
   2 Date:   Mon Jan 5 10:17:25 2009 +0100
   3 Subject: block: get rid of the manual directory counting in blktrace
   4 References: bnc#475149
   5
   6     It can result in a stuck blktrace system, if --kill is used.
   7
   8     Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
   9
  10 Acked-by: Jan Blunck <jblunck@suse.de>
  11 ---
  12  block/blktrace.c |   72 ++++++++++++++++---------------------------------------
  13  1 file changed, 21 insertions(+), 51 deletions(-)
  14
  15 Index: b/block/blktrace.c
  16 ===================================================================
  17 --- a/block/blktrace.c
  18 +++ b/block/blktrace.c
  19 @@ -181,59 +181,12 @@ EXPORT_SYMBOL_GPL(__blk_add_trace);
  20
  21  static struct dentry *blk_tree_root;
  22  static DEFINE_MUTEX(blk_tree_mutex);
  23 -static unsigned int root_users;
  24 -
  25 -static inline void blk_remove_root(void)
  26 -{
  27 -       if (blk_tree_root) {
  28 -               debugfs_remove(blk_tree_root);
  29 -               blk_tree_root = NULL;
  30 -       }
  31 -}
  32 -
  33 -static void blk_remove_tree(struct dentry *dir)
  34 -{
  35 -       mutex_lock(&blk_tree_mutex);
  36 -       debugfs_remove(dir);
  37 -       if (--root_users == 0)
  38 -               blk_remove_root();
  39 -       mutex_unlock(&blk_tree_mutex);
  40 -}
  41 -
  42 -static struct dentry *blk_create_tree(const char *blk_name)
  43 -{
  44 -       struct dentry *dir = NULL;
  45 -       int created = 0;
  46 -
  47 -       mutex_lock(&blk_tree_mutex);
  48 -
  49 -       if (!blk_tree_root) {
  50 -               blk_tree_root = debugfs_create_dir("block", NULL);
  51 -               if (!blk_tree_root)
  52 -                       goto err;
  53 -               created = 1;
  54 -       }
  55 -
  56 -       dir = debugfs_create_dir(blk_name, blk_tree_root);
  57 -       if (dir)
  58 -               root_users++;
  59 -       else {
  60 -               /* Delete root only if we created it */
  61 -               if (created)
  62 -                       blk_remove_root();
  63 -       }
  64 -
  65 -err:
  66 -       mutex_unlock(&blk_tree_mutex);
  67 -       return dir;
  68 -}
  69
  70  static void blk_trace_cleanup(struct blk_trace *bt)
  71  {
  72 -       relay_close(bt->rchan);
  73         debugfs_remove(bt->msg_file);
  74         debugfs_remove(bt->dropped_file);
  75 -       blk_remove_tree(bt->dir);
  76 +       relay_close(bt->rchan);
  77         free_percpu(bt->sequence);
  78         free_percpu(bt->msg_data);
  79         kfree(bt);
  80 @@ -336,7 +289,18 @@ static int blk_subbuf_start_callback(str
  81
  82  static int blk_remove_buf_file_callback(struct dentry *dentry)
  83  {
  84 +       struct dentry *parent = dentry->d_parent;
  85         debugfs_remove(dentry);
  86 +
  87 +       /*
  88 +       * this will fail for all but the last file, but that is ok. what we
  89 +       * care about is the top level buts->name directory going away, when
  90 +       * the last trace file is gone. Then we don't have to rmdir() that
  91 +       * manually on trace stop, so it nicely solves the issue with
  92 +       * force killing of running traces.
  93 +       */
  94 +
  95 +       debugfs_remove(parent);
  96         return 0;
  97  }
  98
  99 @@ -393,7 +357,15 @@ int do_blk_trace_setup(struct request_qu
 100                 goto err;
 101
 102         ret = -ENOENT;
 103 -       dir = blk_create_tree(buts->name);
 104 +
 105 +       if (!blk_tree_root) {
 106 +               blk_tree_root = debugfs_create_dir("block", NULL);
 107 +               if (!blk_tree_root)
 108 +                       return -ENOMEM;
 109 +       }
 110 +
 111 +       dir = debugfs_create_dir(buts->name, blk_tree_root);
 112 +
 113         if (!dir)
 114                 goto err;
 115
 116 @@ -436,8 +408,6 @@ int do_blk_trace_setup(struct request_qu
 117
 118         return 0;
 119  err:
 120 -       if (dir)
 121 -               blk_remove_tree(dir);
 122         if (bt) {
 123                 if (bt->msg_file)
 124                         debugfs_remove(bt->msg_file);