GFS2: Streamline alloc calculations for writes

This patch removes some unused code, and make the calculation
of the number of blocks required conditional in order to reduce
the number of times this (potentially expensive) calculation
is done.

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

1 files changed, 4 insertions, 2 deletions

diff --git a/fs/gfs2/ops_address.c b/fs/gfs2/ops_address.c
index 0df560f4269a..6e4ea36c6605 100644
--- a/fs/gfs2/ops_address.c
+++ b/fs/gfs2/ops_address.c
@@ -625,7 +625,7 @@ static int gfs2_write_begin(struct file *file, struct address_space *mapping,
 {
         struct gfs2_inode *ip = GFS2_I(mapping->host);
         struct gfs2_sbd *sdp = GFS2_SB(mapping->host);
-        unsigned int data_blocks, ind_blocks, rblocks;
+        unsigned int data_blocks = 0, ind_blocks = 0, rblocks;
         int alloc_required;
         int error = 0;
         struct gfs2_alloc *al;
@@ -639,11 +639,13 @@ static int gfs2_write_begin(struct file *file, struct address_space *mapping,
         if (unlikely(error))
                 goto out_uninit;
 
-        gfs2_write_calc_reserv(ip, len, &data_blocks, &ind_blocks);
         error = gfs2_write_alloc_required(ip, pos, len, &alloc_required);
         if (error)
                 goto out_unlock;
 
+        if (alloc_required || gfs2_is_jdata(ip))
+                gfs2_write_calc_reserv(ip, len, &data_blocks, &ind_blocks);
+
         if (alloc_required) {
                 al = gfs2_alloc_get(ip);
                 if (!al) {