[Cluster-devel] [PATCH] GFS2: reread rindex when necessary to grow rindex

[Benjamin Marzinski <bmarzins@redhat.com>]

When GFS2 grew the filesystem, it was never rereading the rindex file during
the grow. This is necessary for large grows when the filesystem is almost full,
and GFS2 needs to use some of the space allocated earlier in the grow to
complete it.  Now, if GFS2 fails to reserve the necessary space and the rindex
file is not uptodate, it rereads it.  Also, the only difference between
gfs2_ri_update() and gfs2_ri_update_special() was that gfs2_ri_update_special()
didn't clear out the existing resource groups, since you knew that it was only
called when there were no resource groups.  Attempting to clear out the
resource groups when there are none takes almost no time, and rarely happens,
so I simply removed gfs2_ri_update_special().

Signed-off-by: Benjamin Marzinski <bmarzins@redhat.com>
---
 fs/gfs2/rgrp.c |   53 +++++++++++------------------------------------------
 1 file changed, 11 insertions(+), 42 deletions(-)

Index: gfs2-2.6-nmw/fs/gfs2/rgrp.c
===================================================================
--- gfs2-2.6-nmw.orig/fs/gfs2/rgrp.c
+++ gfs2-2.6-nmw/fs/gfs2/rgrp.c
@@ -614,46 +614,6 @@ static int gfs2_ri_update(struct gfs2_in
 }
 
 /**
- * gfs2_ri_update_special - Pull in a new resource index from the disk
- *
- * This is a special version that's safe to call from gfs2_inplace_reserve_i.
- * In this case we know that we don't have any resource groups in memory yet.
- *
- * @ip: pointer to the rindex inode
- *
- * Returns: 0 on successful update, error code otherwise
- */
-static int gfs2_ri_update_special(struct gfs2_inode *ip)
-{
-	struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
-	struct inode *inode = &ip->i_inode;
-	struct file_ra_state ra_state;
-	struct gfs2_rgrpd *rgd;
-	unsigned int max_data = 0;
-	int error;
-
-	file_ra_state_init(&ra_state, inode->i_mapping);
-	for (sdp->sd_rgrps = 0;; sdp->sd_rgrps++) {
-		/* Ignore partials */
-		if ((sdp->sd_rgrps + 1) * sizeof(struct gfs2_rindex) >
-		    i_size_read(inode))
-			break;
-		error = read_rindex_entry(ip, &ra_state);
-		if (error) {
-			clear_rgrpdi(sdp);
-			return error;
-		}
-	}
-	list_for_each_entry(rgd, &sdp->sd_rindex_list, rd_list)
-		if (rgd->rd_data > max_data)
-			max_data = rgd->rd_data;
-	sdp->sd_max_rg_data = max_data;
-
-	sdp->sd_rindex_uptodate = 1;
-	return 0;
-}
-
-/**
  * gfs2_rindex_hold - Grab a lock on the rindex
  * @sdp: The GFS2 superblock
  * @ri_gh: the glock holder
@@ -1205,6 +1165,7 @@ int gfs2_inplace_reserve_i(struct gfs2_i
 	struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
 	struct gfs2_alloc *al = ip->i_alloc;
 	int error = 0;
+	int reload_rindex = 0;
 	u64 last_unlinked = NO_BLOCK, unlinked;
 
 	if (gfs2_assert_warn(sdp, al->al_requested))
@@ -1215,8 +1176,12 @@ try_again:
 	   the rindex itself, in which case it's already held. */
 	if (ip != GFS2_I(sdp->sd_rindex))
 		error = gfs2_rindex_hold(sdp, &al->al_ri_gh);
-	else if (!sdp->sd_rgrps) /* We may not have the rindex read in, so: */
-		error = gfs2_ri_update_special(ip);
+	else if (!sdp->sd_rgrps || reload_rindex) {
+		/* We need more space, and the rindex is stale.
+		   reread it */
+		error = gfs2_ri_update(ip);
+		reload_rindex = 0;
+	}
 
 	if (error)
 		return error;
@@ -1229,6 +1194,10 @@ try_again:
 	if (error) {
 		if (ip != GFS2_I(sdp->sd_rindex))
 			gfs2_glock_dq_uninit(&al->al_ri_gh);
+		else if (!sdp->sd_rindex_uptodate) {
+			reload_rindex = 1;
+			goto try_again;
+		}
 		if (error != -EAGAIN)
 			return error;