ext4: Fix small file fragmentation

[linux-2.6-omap-h63xx.git] / fs / ext4 / inode.c

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index d1906d9a22de0b0f7c04deeecc4d7f10ebb72c0a..7e91913e325bb511086c5a2ddb0ddeda0bc28e01 100644 (file)
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -2282,13 +2282,12 @@ static int ext4_da_writepages_trans_blocks(struct inode *inode)
 static int ext4_da_writepages(struct address_space *mapping,
                              struct writeback_control *wbc)
 {
-       struct inode *inode = mapping->host;
        handle_t *handle = NULL;
-       int needed_blocks;
-       int ret = 0;
-       long to_write;
        loff_t range_start = 0;
-       long pages_skipped = 0;
+       struct inode *inode = mapping->host;
+       int needed_blocks, ret = 0, nr_to_writebump = 0;
+       long to_write, pages_skipped = 0;
+       struct ext4_sb_info *sbi = EXT4_SB(mapping->host->i_sb);
 
        /*
         * No pages to write? This is mainly a kludge to avoid starting
@@ -2297,6 +2296,16 @@ static int ext4_da_writepages(struct address_space *mapping,
         */
        if (!mapping->nrpages || !mapping_tagged(mapping, PAGECACHE_TAG_DIRTY))
                return 0;
+       /*
+        * Make sure nr_to_write is >= sbi->s_mb_stream_request
+        * This make sure small files blocks are allocated in
+        * single attempt. This ensure that small files
+        * get less fragmented.
+        */
+       if (wbc->nr_to_write < sbi->s_mb_stream_request) {
+               nr_to_writebump = sbi->s_mb_stream_request - wbc->nr_to_write;
+               wbc->nr_to_write = sbi->s_mb_stream_request;
+       }
 
        if (!wbc->range_cyclic)
                /*
@@ -2377,7 +2386,7 @@ restart_loop:
        }
 
 out_writepages:
-       wbc->nr_to_write = to_write;
+       wbc->nr_to_write = to_write - nr_to_writebump;
        wbc->range_start = range_start;
        return ret;
 }