[GFS2] Journal extent mapping

This patch saves a little time when gfs2 writes to the journals by
keeping a mapping between logical and physical blocks on disk.
That's better than constantly looking up indirect pointers in
buffers, when the journals are several levels of indirection
(which they typically are).

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

1 files changed, 9 insertions, 13 deletions

diff --git a/fs/gfs2/log.c b/fs/gfs2/log.c
index 14333d81cf7d..69a583ec43c7 100644
--- a/fs/gfs2/log.c
+++ b/fs/gfs2/log.c
@@ -1,6 +1,6 @@
 /*
  * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
- * Copyright (C) 2004-2006 Red Hat, Inc.  All rights reserved.
+ * Copyright (C) 2004-2007 Red Hat, Inc.  All rights reserved.
  *
  * This copyrighted material is made available to anyone wishing to use,
  * modify, copy, or redistribute it subject to the terms and conditions
@@ -339,18 +339,14 @@ void gfs2_log_release(struct gfs2_sbd *sdp, unsigned int blks)
 
 static u64 log_bmap(struct gfs2_sbd *sdp, unsigned int lbn)
 {
-        struct inode *inode = sdp->sd_jdesc->jd_inode;
-        int error;
-        struct buffer_head bh_map = { .b_state = 0, .b_blocknr = 0 };
-
-        bh_map.b_size = 1 << inode->i_blkbits;
-        error = gfs2_block_map(inode, lbn, &bh_map, 0);
-        if (error || !bh_map.b_blocknr)
-                printk(KERN_INFO "error=%d, dbn=%llu lbn=%u", error,
-                       (unsigned long long)bh_map.b_blocknr, lbn);
-        gfs2_assert_withdraw(sdp, !error && bh_map.b_blocknr);
-
-        return bh_map.b_blocknr;
+        struct gfs2_journal_extent *je;
+
+        list_for_each_entry(je, &sdp->sd_jdesc->extent_list, extent_list) {
+                if (lbn >= je->lblock && lbn < je->lblock + je->blocks)
+                        return je->dblock + lbn;
+        }
+
+        return -1;
 }
 
 /**