make-ext4-get-inode-loc-plug

   1 ext4: make __ext4_get_inode_loc plug
   2
   3 From: zhangjs <zachary@baishancloud.com>
   4
   5 Add a blk_plug to prevent the inode table readahead from being
   6 submitted as small I/O requests.
   7
   8 Signed-off-by: zhangjs <zachary@baishancloud.com>
   9 Signed-off-by: Theodore Ts'o <tytso@mit.edu>
  10 Reviewed-by: Jan Kara <jack@suse.cz>
  11 ---
  12  fs/ext4/inode.c | 3 +++
  13  1 file changed, 3 insertions(+)
  14
  15 diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
  16 index ed1d8f9ce5f9..11d7c2e403e9 100644
  17 --- a/fs/ext4/inode.c
  18 +++ b/fs/ext4/inode.c
  19 @@ -4570,6 +4570,7 @@ static int __ext4_get_inode_loc(struct inode *inode,
  20         struct buffer_head      *bh;
  21         struct super_block      *sb = inode->i_sb;
  22         ext4_fsblk_t            block;
  23 +       struct blk_plug         plug;
  24         int                     inodes_per_block, inode_offset;
  25
  26         iloc->bh = NULL;
  27 @@ -4658,6 +4659,7 @@ static int __ext4_get_inode_loc(struct inode *inode,
  28                  * If we need to do any I/O, try to pre-readahead extra
  29                  * blocks from the inode table.
  30                  */
  31 +               blk_start_plug(&plug);
  32                 if (EXT4_SB(sb)->s_inode_readahead_blks) {
  33                         ext4_fsblk_t b, end, table;
  34                         unsigned num;
  35 @@ -4688,6 +4690,7 @@ static int __ext4_get_inode_loc(struct inode *inode,
  36                 get_bh(bh);
  37                 bh->b_end_io = end_buffer_read_sync;
  38                 submit_bh(REQ_OP_READ, REQ_META | REQ_PRIO, bh);
  39 +               blk_finish_plug(&plug);
  40                 wait_on_buffer(bh);
  41                 if (!buffer_uptodate(bh)) {
  42                         EXT4_ERROR_INODE_BLOCK(inode, block,