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Re: [Cluster-devel] [PATCH][TRY 5] GFS2: kernel changes to support new gfs2_grow command



David Teigland wrote:
this needs a cast to avoid warnings on some architectures:
	fs_warn(sdp, "File system extended by %llu blocks.\n",
		(unsigned long long)new_free);

Okay.

Correct me if I'm wrong, but I thought all three of these new checks above
wouldn't be needed if it weren't for...
this one call to gfs2_ri_update().  Which is the very special case where
the rindex is being written before gfs has even read it?  I'm trying to
figure out if we can get by without adding those three new checks above
somehow.  If in fact they're only needed due to this one call, it may be
nice to write a new special-purpose function to call here to do the reads
(instead of overloading the normal read function with the special checks),
or add a new arg so the checks can be narrowly applied to this case, or...
read it all at mount time so the problem goes away?

I misunderstood you: I thought you were talking about the previously-added-but-unnecessary function gfs2_check_rindex_version
that I took out with the last revision.

Yes, these functions can be separated out to prune the code of the
extra conditions for this special case.
Since Steve Whitehouse already applied the previous patch to his git
tree, I implemented your suggestions as a new patch, given below.
This is what I did:

To avoid code redundancy, I separated out the operational "guts" into a new function called read_rindex_entry. Then I made two functions: the closer-to-original gfs2_ri_update (without the special condition checks) and gfs2_ri_update_special that's designed with that condition in mind. (I don't like the name, but if you have a suggestion, I'm
all ears).

Oh, and there's an added benefit:  we don't need all the ugly gotos
anymore.  ;)

This patch has been tested with gfs2_fsck_hellfire (which runs for
three and a half hours, btw).

Regards,

Bob Peterson
Red Hat Cluster Suite

Signed-off-By: Bob Peterson <rpeterso redhat com> --
fs/gfs2/ops_address.c |    3 +-
fs/gfs2/rgrp.c        |  139 ++++++++++++++++++++++++++++++++-----------------
2 files changed, 93 insertions(+), 49 deletions(-)

diff --git a/fs/gfs2/ops_address.c b/fs/gfs2/ops_address.c
index 846c0ff..e0b4e8c 100644
--- a/fs/gfs2/ops_address.c
+++ b/fs/gfs2/ops_address.c
@@ -469,7 +469,8 @@ static void adjust_fs_space(struct inode *inode)
	else
		new_free = 0;
	spin_unlock(&sdp->sd_statfs_spin);
-	fs_warn(sdp, "File system extended by %llu blocks.\n", new_free);
+	fs_warn(sdp, "File system extended by %llu blocks.\n",
+		(unsigned long long)new_free);
	gfs2_statfs_change(sdp, new_free, new_free, 0);
}

diff --git a/fs/gfs2/rgrp.c b/fs/gfs2/rgrp.c
index e857f40..48a6461 100644
--- a/fs/gfs2/rgrp.c
+++ b/fs/gfs2/rgrp.c
@@ -463,9 +463,62 @@ u64 gfs2_ri_total(struct gfs2_sbd *sdp)
}

/**
- * gfs2_ri_update - Pull in a new resource index from the disk
+ * read_rindex_entry - Pull in a new resource index entry from the disk
 * @gl: The glock covering the rindex inode
 *
+ * Returns: 0 on success, error code otherwise
+ */
+
+static int read_rindex_entry(struct gfs2_inode *ip,
+			     struct file_ra_state *ra_state)
+{
+	struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
+	loff_t pos = sdp->sd_rgrps * sizeof(struct gfs2_rindex);
+	char buf[sizeof(struct gfs2_rindex)];
+	int error;
+	struct gfs2_rgrpd *rgd;
+
+	error = gfs2_internal_read(ip, ra_state, buf, &pos,
+				   sizeof(struct gfs2_rindex));
+	if (!error)
+		return 0;
+	if (error != sizeof(struct gfs2_rindex)) {
+		if (error > 0)
+			error = -EIO;
+		return error;
+	}
+
+	rgd = kzalloc(sizeof(struct gfs2_rgrpd), GFP_NOFS);
+	error = -ENOMEM;
+	if (!rgd)
+		return error;
+
+	mutex_init(&rgd->rd_mutex);
+	lops_init_le(&rgd->rd_le, &gfs2_rg_lops);
+	rgd->rd_sbd = sdp;
+
+	list_add_tail(&rgd->rd_list, &sdp->sd_rindex_list);
+	list_add_tail(&rgd->rd_list_mru, &sdp->sd_rindex_mru_list);
+
+	gfs2_rindex_in(&rgd->rd_ri, buf);
+	error = compute_bitstructs(rgd);
+	if (error)
+		return error;
+
+	error = gfs2_glock_get(sdp, rgd->rd_ri.ri_addr,
+			       &gfs2_rgrp_glops, CREATE, &rgd->rd_gl);
+	if (error)
+		return error;
+
+	rgd->rd_gl->gl_object = rgd;
+	rgd->rd_rg_vn = rgd->rd_gl->gl_vn - 1;
+	return error;
+}
+
+/**
+ * gfs2_ri_update - Pull in a new resource index from the disk
+ * @ip: pointer to the rindex inode
+ *
 * Returns: 0 on successful update, error code otherwise
 */

@@ -473,18 +526,11 @@ static int gfs2_ri_update(struct gfs2_inode *ip)
{
	struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
	struct inode *inode = &ip->i_inode;
-	struct gfs2_rgrpd *rgd;
-	char buf[sizeof(struct gfs2_rindex)];
	struct file_ra_state ra_state;
	u64 junk = ip->i_di.di_size;
	int error;

-	/* If someone is holding the rindex file with a glock, they must
-	   be updating it, in which case we may have partial entries.
-	   In this case, we ignore the partials. */
-	if (!gfs2_glock_is_held_excl(ip->i_gl) &&
-	    !gfs2_glock_is_held_shrd(ip->i_gl) &&
-	    do_div(junk, sizeof(struct gfs2_rindex))) {
+	if (do_div(junk, sizeof(struct gfs2_rindex))) {
		gfs2_consist_inode(ip);
		return -EIO;
	}
@@ -493,52 +539,49 @@ static int gfs2_ri_update(struct gfs2_inode *ip)

	file_ra_state_init(&ra_state, inode->i_mapping);
	for (sdp->sd_rgrps = 0;; sdp->sd_rgrps++) {
-		loff_t pos = sdp->sd_rgrps * sizeof(struct gfs2_rindex);
-
-		if (pos + sizeof(struct gfs2_rindex) >= ip->i_di.di_size)
-			break;
-		error = gfs2_internal_read(ip, &ra_state, buf, &pos,
-					    sizeof(struct gfs2_rindex));
-		if (!error)
-			break;
-		if (error != sizeof(struct gfs2_rindex)) {
-			if (error > 0)
-				error = -EIO;
-			goto fail;
+		error = read_rindex_entry(ip, &ra_state);
+		if (error) {
+			clear_rgrpdi(sdp);
+			return error;
		}
+	}

-		rgd = kzalloc(sizeof(struct gfs2_rgrpd), GFP_NOFS);
-		error = -ENOMEM;
-		if (!rgd)
-			goto fail;
-
-		mutex_init(&rgd->rd_mutex);
-		lops_init_le(&rgd->rd_le, &gfs2_rg_lops);
-		rgd->rd_sbd = sdp;
-
-		list_add_tail(&rgd->rd_list, &sdp->sd_rindex_list);
-		list_add_tail(&rgd->rd_list_mru, &sdp->sd_rindex_mru_list);
-
-		gfs2_rindex_in(&rgd->rd_ri, buf);
-		error = compute_bitstructs(rgd);
-		if (error)
-			goto fail;
+	sdp->sd_rindex_vn = ip->i_gl->gl_vn;
+	return 0;
+}

-		error = gfs2_glock_get(sdp, rgd->rd_ri.ri_addr,
-				       &gfs2_rgrp_glops, CREATE, &rgd->rd_gl);
-		if (error)
-			goto fail;
+/**
+ * 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;
+	int error;

-		rgd->rd_gl->gl_object = rgd;
-		rgd->rd_rg_vn = rgd->rd_gl->gl_vn - 1;
+	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) >
+		    ip->i_di.di_size)
+			break;
+		error = read_rindex_entry(ip, &ra_state);
+		if (error) {
+			clear_rgrpdi(sdp);
+			return error;
+		}
	}

	sdp->sd_rindex_vn = ip->i_gl->gl_vn;
	return 0;
-
-fail:
-	clear_rgrpdi(sdp);
-	return error;
}

/**
@@ -1028,7 +1071,7 @@ int gfs2_inplace_reserve_i(struct gfs2_inode *ip, char *file, unsigned int line)
	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(ip);
+		error = gfs2_ri_update_special(ip);

	if (error)
		return error;


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