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>

diff --git a/fs/nilfs2/mdt.c b/fs/nilfs2/mdt.c
index 3028e8f..948b1f8 100644 (file)
--- 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);