ldiskfs/kernel_patches/patches/ext4-lock-cached_extent.patch

   1 Index: linux-2.6.27.21-0.1/fs/ext4/extents.c
   2 ===================================================================
   3 --- linux-2.6.27.21-0.1.orig/fs/ext4/extents.c  2009-06-19 15:50:57.000000000 +0530
   4 +++ linux-2.6.27.21-0.1/fs/ext4/extents.c       2009-06-19 15:56:32.000000000 +0530
   5 @@ -1736,11 +1736,13 @@
   6  {
   7         struct ext4_ext_cache *cex;
   8         BUG_ON(len == 0);
   9 +       spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
  10         cex = &EXT4_I(inode)->i_cached_extent;
  11         cex->ec_type = type;
  12         cex->ec_block = block;
  13         cex->ec_len = len;
  14         cex->ec_start = start;
  15 +       spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
  16  }
  17
  18  /*
  19 @@ -1797,12 +1799,17 @@
  20                         struct ext4_extent *ex)
  21  {
  22         struct ext4_ext_cache *cex;
  23 +       int ret = EXT4_EXT_CACHE_NO;
  24
  25 +       /*
  26 +        * We borrow i_block_reservation_lock to protect i_cached_extent
  27 +        */
  28 +       spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
  29         cex = &EXT4_I(inode)->i_cached_extent;
  30
  31         /* has cache valid data? */
  32         if (cex->ec_type == EXT4_EXT_CACHE_NO)
  33 -               return EXT4_EXT_CACHE_NO;
  34 +               goto errout;
  35
  36         BUG_ON(cex->ec_type != EXT4_EXT_CACHE_GAP &&
  37                         cex->ec_type != EXT4_EXT_CACHE_EXTENT);
  38 @@ -1813,11 +1820,12 @@
  39                 ext_debug("%u cached by %u:%u:%llu\n",
  40                                 block,
  41                                 cex->ec_block, cex->ec_len, cex->ec_start);
  42 -               return cex->ec_type;
  43 +               ret = cex->ec_type;
  44         }
  45
  46 -       /* not in cache */
  47 -       return EXT4_EXT_CACHE_NO;
  48 +errout:
  49 +       spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
  50 +       return ret;
  51  }
  52
  53  /*