[PATCH] ext4: make __ext4_get_inode_loc plug

[jinshui zhang <leozhangjs@gmail.com>]

From: zhangjs <zachary@baishancloud.com>

If the task is unplugged when called, the inode_readahead_blks may not be merged, 
these will cause small pieces of io, It should be plugged.

Signed-off-by: zhangjs <zachary@baishancloud.com>
---
 fs/ext4/inode.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index c7f77c6..8fe046b 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -4570,6 +4570,7 @@ static int __ext4_get_inode_loc(struct inode *inode,
 	struct buffer_head	*bh;
 	struct super_block	*sb = inode->i_sb;
 	ext4_fsblk_t		block;
+	struct blk_plug		plug;
 	int			inodes_per_block, inode_offset;
 
 	iloc->bh = NULL;
@@ -4654,6 +4655,8 @@ static int __ext4_get_inode_loc(struct inode *inode,
 		}
 
 make_io:
+		blk_start_plug(&plug);
+
 		/*
 		 * If we need to do any I/O, try to pre-readahead extra
 		 * blocks from the inode table.
@@ -4688,6 +4691,9 @@ static int __ext4_get_inode_loc(struct inode *inode,
 		get_bh(bh);
 		bh->b_end_io = end_buffer_read_sync;
 		submit_bh(REQ_OP_READ, REQ_META | REQ_PRIO, bh);
+
+		blk_finish_plug(&plug);
+
 		wait_on_buffer(bh);
 		if (!buffer_uptodate(bh)) {
 			EXT4_ERROR_INODE_BLOCK(inode, block,
-- 
1.8.3.1