preload-block-group-descriptors

   1 ext4: preload block group descriptors
   2
   3 From: Andrew Perepechko <andrew.perepechko@seagate.com>
   4
   5 With enabled meta_bg option block group descriptors
   6 reading IO is not sequential and requires optimization.
   7
   8 Signed-off-by: Andrew Perepechko <andrew.perepechko@seagate.com>
   9 Signed-off-by: Theodore Ts'o <tytso@mit.edu>
  10 ---
  11  fs/ext4/super.c | 6 ++++++
  12  1 file changed, 6 insertions(+)
  13
  14 diff --git a/fs/ext4/super.c b/fs/ext4/super.c
  15 index a673558..0e52c91 100644
  16 --- a/fs/ext4/super.c
  17 +++ b/fs/ext4/super.c
  18 @@ -3879,6 +3879,12 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
  19
  20         bgl_lock_init(sbi->s_blockgroup_lock);
  21
  22 +       /* Pre-read the descriptors into the buffer cache */
  23 +       for (i = 0; i < db_count; i++) {
  24 +               block = descriptor_loc(sb, logical_sb_block, i);
  25 +               sb_breadahead(sb, block);
  26 +       }
  27 +
  28         for (i = 0; i < db_count; i++) {
  29                 block = descriptor_loc(sb, logical_sb_block, i);
  30                 sbi->s_group_desc[i] = sb_bread_unmovable(sb, block);
  31 --
  32 1.8.3.1
  33
  34