LU-14131 osd-ldiskfs: reduce credits for overwritting

If all blocks are mapped which means this is overwritting
case or space has been allocated by fallocate.

There is no need to modify exten tree, and we only
need 1 credits for inode.

Signed-off-by: Wang Shilong <wshilong@ddn.com>
Change-Id: I907861d4862256a8a23a81812953e2330e1d9925
Reviewed-on: https://review.whamcloud.com/40604
Tested-by: jenkins <devops@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Alex Zhuravlev <bzzz@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>

diff --git a/lustre/osd-ldiskfs/osd_io.c b/lustre/osd-ldiskfs/osd_io.c
index d65421c..2814cfe 100644 (file)
--- a/lustre/osd-ldiskfs/osd_io.c
+++ b/lustre/osd-ldiskfs/osd_io.c
@@ -1154,6 +1154,13 @@ static int osd_declare_write_commit(const struct lu_env *env,
                quota_space += PAGE_SIZE;
        }
 
                quota_space += PAGE_SIZE;
        }
 

+       credits++; /* inode */
+       /*
+        * overwrite case, no need to modify tree and
+        * allocate blocks.
+        */
+       if (!newblocks)
+               goto out_declare;

        /*
         * each extent can go into new leaf causing a split
         * 5 is max tree depth: inode + 4 index blocks
        /*
         * each extent can go into new leaf causing a split
         * 5 is max tree depth: inode + 4 index blocks


@@ -1167,12 +1174,10 @@ static int osd_declare_write_commit(const struct lu_env *env,
                depth = ext_depth(inode);
                depth = max(depth, 1) + 1;
                newblocks += depth;
                depth = ext_depth(inode);
                depth = max(depth, 1) + 1;
                newblocks += depth;

-               credits++; /* inode */

                credits += depth * 2 * extents;
        } else {
                depth = 3;
                newblocks += depth;
                credits += depth * 2 * extents;
        } else {
                depth = 3;
                newblocks += depth;

-               credits++; /* inode */

                credits += depth * extents;
        }
 
                credits += depth * extents;
        }
 


@@ -1196,6 +1201,7 @@ static int osd_declare_write_commit(const struct lu_env *env,
        else
                credits += newblocks;
 
        else
                credits += newblocks;
 

+out_declare:

        osd_trans_declare_op(env, oh, OSD_OT_WRITE, credits);
 
        /* make sure the over quota flags were not set */
        osd_trans_declare_op(env, oh, OSD_OT_WRITE, credits);
 
        /* make sure the over quota flags were not set */