GFS2: Make resource groups "append only" during life of fs

Since we have ruled out supporting online filesystem shrink,
it is possible to make the resource group list append only
during the life of a super block. This gives several benefits:

Firstly, we only need to read new rindex elements as they are added
rather than needing to reread the whole rindex file each time one
element is added.

Secondly, the rindex glock can be held for much shorter periods of
time, and is completely removed from the fast path for allocations.
The lock is taken in shared mode only when updating the resource
groups when the first allocation occurs, and after a grow has
taken place.

Thirdly, this results in a reduction in code size, and everything
gets a lot simpler to understand in this area.

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

1 files changed, 7 insertions, 10 deletions

diff --git a/fs/gfs2/rgrp.h b/fs/gfs2/rgrp.h
index 59b950f43ccf..0439fca18f08 100644
--- a/fs/gfs2/rgrp.h
+++ b/fs/gfs2/rgrp.h
@@ -18,13 +18,13 @@ struct gfs2_holder;
 
 extern void gfs2_rgrp_verify(struct gfs2_rgrpd *rgd);
 
-struct gfs2_rgrpd *gfs2_blk2rgrpd(struct gfs2_sbd *sdp, u64 blk);
-struct gfs2_rgrpd *gfs2_rgrpd_get_first(struct gfs2_sbd *sdp);
-struct gfs2_rgrpd *gfs2_rgrpd_get_next(struct gfs2_rgrpd *rgd);
+extern struct gfs2_rgrpd *gfs2_blk2rgrpd(struct gfs2_sbd *sdp, u64 blk);
+extern struct gfs2_rgrpd *gfs2_rgrpd_get_first(struct gfs2_sbd *sdp);
+extern struct gfs2_rgrpd *gfs2_rgrpd_get_next(struct gfs2_rgrpd *rgd);
 
 extern void gfs2_clear_rgrpd(struct gfs2_sbd *sdp);
-extern int gfs2_rindex_hold(struct gfs2_sbd *sdp, struct gfs2_holder *ri_gh);
-
+extern int gfs2_rindex_update(struct gfs2_sbd *sdp);
+extern void gfs2_free_clones(struct gfs2_rgrpd *rgd);
 extern int gfs2_rgrp_go_lock(struct gfs2_holder *gh);
 extern void gfs2_rgrp_go_unlock(struct gfs2_holder *gh);
 
@@ -36,16 +36,13 @@ static inline void gfs2_alloc_put(struct gfs2_inode *ip)
         ip->i_alloc = NULL;
 }
 
-extern int gfs2_inplace_reserve_i(struct gfs2_inode *ip, int hold_rindex,
+extern int gfs2_inplace_reserve_i(struct gfs2_inode *ip,
                                   char *file, unsigned int line);
 #define gfs2_inplace_reserve(ip) \
-        gfs2_inplace_reserve_i((ip), 1, __FILE__, __LINE__)
-#define gfs2_inplace_reserve_ri(ip) \
-        gfs2_inplace_reserve_i((ip), 0, __FILE__, __LINE__)
+        gfs2_inplace_reserve_i((ip),  __FILE__, __LINE__)
 
 extern void gfs2_inplace_release(struct gfs2_inode *ip);
 
-extern int gfs2_ri_update(struct gfs2_inode *ip);
 extern int gfs2_alloc_block(struct gfs2_inode *ip, u64 *bn, unsigned int *n);
 extern int gfs2_alloc_di(struct gfs2_inode *ip, u64 *bn, u64 *generation);