merge-uninitialized-extents

   1 ext4: merge uninitialized extents
   2
   3 From: Darrick J. Wong <darrick.wong@oracle.com>
   4
   5 Allow for merging uninitialized extents.
   6
   7 Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
   8 Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
   9 ---
  10  fs/ext4/extents.c |   21 +++++++++++++++++----
  11  1 file changed, 17 insertions(+), 4 deletions(-)
  12
  13 diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
  14 index 3384dc4..7f0132d 100644
  15 --- a/fs/ext4/extents.c
  16 +++ b/fs/ext4/extents.c
  17 @@ -1691,7 +1691,7 @@ ext4_can_extents_be_merged(struct inode *inode, struct ext4_extent *ex1,
  18          * the extent that was written properly split out and conversion to
  19          * initialized is trivial.
  20          */
  21 -       if (ext4_ext_is_uninitialized(ex1) || ext4_ext_is_uninitialized(ex2))
  22 +       if (ext4_ext_is_uninitialized(ex1) != ext4_ext_is_uninitialized(ex2))
  23                 return 0;
  24
  25         ext1_ee_len = ext4_ext_get_actual_len(ex1);
  26 @@ -1708,6 +1708,11 @@ ext4_can_extents_be_merged(struct inode *inode, struct ext4_extent *ex1,
  27          */
  28         if (ext1_ee_len + ext2_ee_len > EXT_INIT_MAX_LEN)
  29                 return 0;
  30 +       if (ext4_ext_is_uninitialized(ex1) &&
  31 +           (ext4_test_inode_state(inode, EXT4_STATE_DIO_UNWRITTEN) ||
  32 +            atomic_read(&EXT4_I(inode)->i_unwritten) ||
  33 +            (ext1_ee_len + ext2_ee_len > EXT_UNINIT_MAX_LEN)))
  34 +               return 0;
  35  #ifdef AGGRESSIVE_TEST
  36         if (ext1_ee_len >= 4)
  37                 return 0;
  38 @@ -1731,7 +1736,7 @@ static int ext4_ext_try_to_merge_right(struct inode *inode,
  39  {
  40         struct ext4_extent_header *eh;
  41         unsigned int depth, len;
  42 -       int merge_done = 0;
  43 +       int merge_done = 0, uninit;
  44
  45         depth = ext_depth(inode);
  46         BUG_ON(path[depth].p_hdr == NULL);
  47 @@ -1741,8 +1746,11 @@ static int ext4_ext_try_to_merge_right(struct inode *inode,
  48                 if (!ext4_can_extents_be_merged(inode, ex, ex + 1))
  49                         break;
  50                 /* merge with next extent! */
  51 +               uninit = ext4_ext_is_uninitialized(ex);
  52                 ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
  53                                 + ext4_ext_get_actual_len(ex + 1));
  54 +               if (uninit)
  55 +                       ext4_ext_mark_uninitialized(ex);
  56
  57                 if (ex + 1 < EXT_LAST_EXTENT(eh)) {
  58                         len = (EXT_LAST_EXTENT(eh) - ex - 1)
  59 @@ -1896,7 +1904,7 @@ int ext4_ext_insert_extent(handle_t *handle, struct inode *inode,
  60         struct ext4_ext_path *npath = NULL;
  61         int depth, len, err;
  62         ext4_lblk_t next;
  63 -       int mb_flags = 0;
  64 +       int mb_flags = 0, uninit;
  65
  66         if (unlikely(ext4_ext_get_actual_len(newext) == 0)) {
  67                 EXT4_ERROR_INODE(inode, "ext4_ext_get_actual_len(newext) == 0");
  68 @@ -1946,9 +1954,11 @@ int ext4_ext_insert_extent(handle_t *handle, struct inode *inode,
  69                                                   path + depth);
  70                         if (err)
  71                                 return err;
  72 -
  73 +                       uninit = ext4_ext_is_uninitialized(ex);
  74                         ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
  75                                         + ext4_ext_get_actual_len(newext));
  76 +                       if (uninit)
  77 +                               ext4_ext_mark_uninitialized(ex);
  78                         eh = path[depth].p_hdr;
  79                         nearex = ex;
  80                         goto merge;
  81 @@ -1971,10 +1981,13 @@ prepend:
  82                         if (err)
  83                                 return err;
  84
  85 +                       uninit = ext4_ext_is_uninitialized(ex);
  86                         ex->ee_block = newext->ee_block;
  87                         ext4_ext_store_pblock(ex, ext4_ext_pblock(newext));
  88                         ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
  89                                         + ext4_ext_get_actual_len(newext));
  90 +                       if (uninit)
  91 +                               ext4_ext_mark_uninitialized(ex);
  92                         eh = path[depth].p_hdr;
  93                         nearex = ex;
  94                         goto merge;
  95