nilfs2: avoid readahead on metadata file for create mode

This turns off readhead action of metadata file if nilfs_mdt_get_block
function was called with a create flag.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

1 files changed, 15 insertions, 13 deletions

diff --git a/fs/nilfs2/mdt.c b/fs/nilfs2/mdt.c
index 3028e8f31be2..948b1f8bc505 100644
--- a/fs/nilfs2/mdt.c
+++ b/fs/nilfs2/mdt.c
@@ -186,7 +186,7 @@ nilfs_mdt_submit_block(struct inode *inode, unsigned long blkoff,
 }
 
 static int nilfs_mdt_read_block(struct inode *inode, unsigned long block,
-                                struct buffer_head **out_bh)
+                                int readahead, struct buffer_head **out_bh)
 {
         struct buffer_head *first_bh, *bh;
         unsigned long blkoff;
@@ -200,16 +200,18 @@ static int nilfs_mdt_read_block(struct inode *inode, unsigned long block,
         if (unlikely(err))
                 goto failed;
 
-        blkoff = block + 1;
-        for (i = 0; i < nr_ra_blocks; i++, blkoff++) {
-                err = nilfs_mdt_submit_block(inode, blkoff, READA, &bh);
-                if (likely(!err || err == -EEXIST))
-                        brelse(bh);
-                else if (err != -EBUSY)
-                        break; /* abort readahead if bmap lookup failed */
-
-                if (!buffer_locked(first_bh))
-                        goto out_no_wait;
+        if (readahead) {
+                blkoff = block + 1;
+                for (i = 0; i < nr_ra_blocks; i++, blkoff++) {
+                        err = nilfs_mdt_submit_block(inode, blkoff, READA, &bh);
+                        if (likely(!err || err == -EEXIST))
+                                brelse(bh);
+                        else if (err != -EBUSY)
+                                break;
+                                /* abort readahead if bmap lookup failed */
+                        if (!buffer_locked(first_bh))
+                                goto out_no_wait;
+                }
         }
 
         wait_on_buffer(first_bh);
@@ -263,7 +265,7 @@ int nilfs_mdt_get_block(struct inode *inode, unsigned long blkoff, int create,
 
         /* Should be rewritten with merging nilfs_mdt_read_block() */
  retry:
-        ret = nilfs_mdt_read_block(inode, blkoff, out_bh);
+        ret = nilfs_mdt_read_block(inode, blkoff, !create, out_bh);
         if (!create || ret != -ENOENT)
                 return ret;
 
@@ -371,7 +373,7 @@ int nilfs_mdt_mark_block_dirty(struct inode *inode, unsigned long block)
         struct buffer_head *bh;
         int err;
 
-        err = nilfs_mdt_read_block(inode, block, &bh);
+        err = nilfs_mdt_read_block(inode, block, 0, &bh);
         if (unlikely(err))
                 return err;
         nilfs_mark_buffer_dirty(bh);