GFS2: Extend the life of the reservations

This patch lengthens the lifespan of the reservations structure for
inodes. Before, they were allocated and deallocated for every write
operation. With this patch, they are allocated when the first write
occurs, and deallocated when the last process closes the file.
It's more efficient to do it this way because it saves GFS2 a lot of
unnecessary allocates and frees. It also gives us more flexibility
for the future: (1) we can now fold the qadata structure back into
the structure and save those alloc/frees, (2) we can use this for
multi-block reservations.

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

1 files changed, 1 insertions, 1 deletions

diff --git a/fs/gfs2/trans.h b/fs/gfs2/trans.h
index 125d4572e1c02..41f42cdccbb8e 100644
--- a/fs/gfs2/trans.h
+++ b/fs/gfs2/trans.h
@@ -31,7 +31,7 @@ struct gfs2_glock;
 static inline unsigned int gfs2_rg_blocks(const struct gfs2_inode *ip)
 {
 	const struct gfs2_blkreserv *rs = ip->i_res;
-	if (rs->rs_requested < ip->i_rgd->rd_length)
+	if (rs && rs->rs_requested < ip->i_rgd->rd_length)
 		return rs->rs_requested + 1;
 	return ip->i_rgd->rd_length;
 }