[GFS2] Use ->page_mkwrite() for mmap()

This cleans up the mmap() code path for GFS2 by implementing the
page_mkwrite function for GFS2. We are thus able to use the
generic filemap_fault function for our ->fault() implementation.

This now means that shared writable mappings will be much more
efficiently shared across the cluster if there is a reasonable
proportion of read activity (the greater proportion, the better).

As a side effect, it also reduces the size of the code, removes
special cases from readpage and readpages, and makes the code
path easier to follow.

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

1 files changed, 1 insertions, 8 deletions

diff --git a/fs/gfs2/glops.c b/fs/gfs2/glops.c
index 4670dcb2a877..110f03d66f4b 100644
--- a/fs/gfs2/glops.c
+++ b/fs/gfs2/glops.c
@@ -86,15 +86,10 @@ static void gfs2_pte_inval(struct gfs2_glock *gl)
         if (!ip || !S_ISREG(inode->i_mode))
                 return;
 
-        if (!test_bit(GIF_PAGED, &ip->i_flags))
-                return;
-
         unmap_shared_mapping_range(inode->i_mapping, 0, 0);
-
         if (test_bit(GIF_SW_PAGED, &ip->i_flags))
                 set_bit(GLF_DIRTY, &gl->gl_flags);
 
-        clear_bit(GIF_SW_PAGED, &ip->i_flags);
 }
 
 /**
@@ -234,10 +229,8 @@ static void inode_go_inval(struct gfs2_glock *gl, int flags)
                         set_bit(GIF_INVALID, &ip->i_flags);
         }
 
-        if (ip && S_ISREG(ip->i_inode.i_mode)) {
+        if (ip && S_ISREG(ip->i_inode.i_mode))
                 truncate_inode_pages(ip->i_inode.i_mapping, 0);
-                clear_bit(GIF_PAGED, &ip->i_flags);
-        }
 }
 
 /**