ext3: Update ctime in ext3_splice_branch() only when needed
Kazuya Mio [Wed, 8 Feb 2012 07:34:29 +0000 (16:34 +0900)]
Currently ext3 updates ctime in ext3_splice_branch() which is called whenever
we allocate one block. But it is wasteful because ext3 doesn't support
nanosecond timestamp. This leads to a performance loss.

Signed-off-by: Kazuya Mio <k-mio@sx.jp.nec.com>
Signed-off-by: Jan Kara <jack@suse.cz>

fs/ext3/inode.c

index 2d0afec..6d34186 100644 (file)
@@ -756,6 +756,7 @@ static int ext3_splice_branch(handle_t *handle, struct inode *inode,
        struct ext3_block_alloc_info *block_i;
        ext3_fsblk_t current_block;
        struct ext3_inode_info *ei = EXT3_I(inode);
+       struct timespec now;
 
        block_i = ei->i_block_alloc_info;
        /*
@@ -795,9 +796,11 @@ static int ext3_splice_branch(handle_t *handle, struct inode *inode,
        }
 
        /* We are done with atomic stuff, now do the rest of housekeeping */
-
-       inode->i_ctime = CURRENT_TIME_SEC;
-       ext3_mark_inode_dirty(handle, inode);
+       now = CURRENT_TIME_SEC;
+       if (!timespec_equal(&inode->i_ctime, &now) || !where->bh) {
+               inode->i_ctime = now;
+               ext3_mark_inode_dirty(handle, inode);
+       }
        /* ext3_mark_inode_dirty already updated i_sync_tid */
        atomic_set(&ei->i_datasync_tid, handle->h_transaction->t_tid);