From: Wendy Cheng <wcheng@redhat.com>
Subject: [RHEL5 PATCH] Fix gfs2_rename lock ordering (for local filesystem)
Date: Mon, 08 Jan 2007 11:05:30 -0500
Bugzilla: 221237
Message-Id: <45A26BCA.6050409@redhat.com>
Changelog: gfs: Fix gfs2_rename lock ordering (for local filesystem)


Second round of gfs2_rename lock re-ordering to allow Anaconda adding 
root partition on top of gfs2. Check out bugzilla 221237 for details.

-- Wendy

 Signed-off-by: S. Wendy Cheng <wcheng@redhat.com>
 
 fs/gfs2/inode.c     |   53 +++++++++++++++++++++++++++++++---------------------
 fs/gfs2/inode.h     |    2 -
 fs/gfs2/ops_inode.c |   25 ++----------------------
 3 files changed, 36 insertions(+), 44 deletions(-)

--- linux-2.6.18.i386/fs/gfs2/inode.h	2007-01-05 22:20:46.000000000 -0500
+++ linux/fs/gfs2/inode.h	2007-01-05 22:32:45.000000000 -0500
@@ -34,7 +34,7 @@ int gfs2_inode_refresh(struct gfs2_inode
 
 int gfs2_dinode_dealloc(struct gfs2_inode *inode);
 int gfs2_change_nlink(struct gfs2_inode *ip, int diff);
-int gfs2_change_nlink_i(struct gfs2_inode *ip, int diff);
+int gfs2_change_nlink_i(struct gfs2_inode *ip);
 struct inode *gfs2_lookupi(struct inode *dir, const struct qstr *name,
 			   int is_root, struct nameidata *nd);
 struct inode *gfs2_createi(struct gfs2_holder *ghs, const struct qstr *name,
--- linux-2.6.18.i386/fs/gfs2/ops_inode.c	2007-01-05 22:20:46.000000000 -0500
+++ linux/fs/gfs2/ops_inode.c	2007-01-05 23:25:05.000000000 -0500
@@ -583,7 +583,6 @@ static int gfs2_rename(struct inode *odi
 	int alloc_required;
 	unsigned int x;
 	int error;
-	struct gfs2_rgrpd *rgd;
 
 	if (ndentry->d_inode) {
 		nip = GFS2_I(ndentry->d_inode);
@@ -717,12 +716,12 @@ static int gfs2_rename(struct inode *odi
 		error = gfs2_trans_begin(sdp, sdp->sd_max_dirres +
 					 al->al_rgd->rd_ri.ri_length +
 					 4 * RES_DINODE + 4 * RES_LEAF +
-					 RES_STATFS + RES_QUOTA + 1, 0);
+					 RES_STATFS + RES_QUOTA + 4, 0);
 		if (error)
 			goto out_ipreserv;
 	} else {
 		error = gfs2_trans_begin(sdp, 4 * RES_DINODE +
-					 5 * RES_LEAF + 1, 0);
+					 5 * RES_LEAF + 4, 0);
 		if (error)
 			goto out_gunlock;
 	}
@@ -736,25 +735,7 @@ static int gfs2_rename(struct inode *odi
 			error = gfs2_dir_del(ndip, &ndentry->d_name);
 			if (error)
 				goto out_end_trans;
-			error = gfs2_change_nlink_i(nip, -1);
-			if ((!error) && (nip->i_di.di_nlink == 0)) {
-				error = -EIO;
-				rgd = gfs2_blk2rgrpd(sdp, nip->i_num.no_addr);
-				if (rgd) {
-					struct gfs2_holder nlink_rg_gh;
-					if (rgd != nip->i_alloc.al_rgd) 
-						error = gfs2_glock_nq_init(
-						rgd->rd_gl, LM_ST_EXCLUSIVE, 
-						0, &nlink_rg_gh);
-					else 
-						error = 0;
-                			if (!error) {
-						gfs2_unlink_di(&nip->i_inode);
-						if (rgd != nip->i_alloc.al_rgd) 
-							gfs2_glock_dq_uninit(&nlink_rg_gh);
-					}
-				}
-			}
+			error = gfs2_change_nlink(nip, -1);
 		}
 		if (error)
 			goto out_end_trans;
--- linux-2.6.18.i386/fs/gfs2/inode.c	2007-01-05 22:20:46.000000000 -0500
+++ linux/fs/gfs2/inode.c	2007-01-06 00:08:39.000000000 -0500
@@ -301,13 +301,13 @@ out:
 }
 
 /**
- * gfs2_change_nlink_i - Change nlink count on inode
+ * gfs2_change_nlink - Change nlink count on inode
  * @ip: The GFS2 inode
  * @diff: The change in the nlink count required
  *
  * Returns: errno
  */
-int gfs2_change_nlink_i(struct gfs2_inode *ip, int diff)
+int gfs2_change_nlink(struct gfs2_inode *ip, int diff)
 {
 	struct buffer_head *dibh;
 	u32 nlink;
@@ -337,40 +337,52 @@ int gfs2_change_nlink_i(struct gfs2_inod
 	brelse(dibh);
 	mark_inode_dirty(&ip->i_inode);
 
+        if (ip->i_di.di_nlink == 0)
+                error = gfs2_change_nlink_i(ip);
+
 	return error;
 }
 
-int gfs2_change_nlink(struct gfs2_inode *ip, int diff)
+int gfs2_change_nlink_i(struct gfs2_inode *ip)
 {
 	struct gfs2_sbd *sdp = ip->i_inode.i_sb->s_fs_info;
-	int error;
-
-	/* update the nlink */
-	error = gfs2_change_nlink_i(ip, diff);
-	if (error)
-		return error;
-
-	/* return meta data block back to rg */
-	if (ip->i_di.di_nlink == 0) {
-		struct gfs2_rgrpd *rgd;
-		struct gfs2_holder ri_gh, rg_gh;
-
+	struct gfs2_inode *rindex = GFS2_I(sdp->sd_rindex);
+	struct gfs2_glock *ri_gl = rindex->i_gl;
+	struct gfs2_rgrpd *rgd;
+	struct gfs2_holder ri_gh, rg_gh;
+	int existing, error;
+
+	/* if we come from rename path, we could have the lock already */
+	existing = gfs2_glock_is_locked_by_me(ri_gl);
+	if (!existing) {
 		error = gfs2_rindex_hold(sdp, &ri_gh);
 		if (error)
 			goto out;
-		error = -EIO;
-		rgd = gfs2_blk2rgrpd(sdp, ip->i_num.no_addr);
-		if (!rgd)
-			goto out_norgrp;
+	}
+
+	/* find the matching rgd */
+	error = -EIO;
+	rgd = gfs2_blk2rgrpd(sdp, ip->i_num.no_addr);
+	if (!rgd)
+		goto out_norgrp;
+
+	/* 
+	 * Eventually we may want to move rgd(s) to a linked list
+	 * and piggyback the free logic into one of gfs2 daemons
+	 * to gain some performance. 
+	 */
+	if (!rgd->rd_gl || !gfs2_glock_is_locked_by_me(rgd->rd_gl)) {
 		error = gfs2_glock_nq_init(rgd->rd_gl, LM_ST_EXCLUSIVE, 0, &rg_gh);
 		if (error)
 			goto out_norgrp;
 
 		gfs2_unlink_di(&ip->i_inode); /* mark inode unlinked */
 		gfs2_glock_dq_uninit(&rg_gh);
+	}
+
 out_norgrp:
+	if (!existing)	
 		gfs2_glock_dq_uninit(&ri_gh);
-	}
 out:
 	return error;
 }
@@ -382,7 +394,6 @@ struct inode *gfs2_lookup_simple(struct 
 	return gfs2_lookupi(dip, &qstr, 1, NULL);
 }
 
-
 /**
  * gfs2_lookupi - Look up a filename in a directory and return its inode
  * @d_gh: An initialized holder for the directory glock