[Cluster-devel] [GFS2 PATCH 1/2] gfs2: separate holder for rgrps in gfs2_rename

[Bob Peterson]

Before this patch, gfs2_rename added a holder for the rgrp glock to
its array of holders, ghs. There's nothing wrong with that, but this
patch separates it into a separate holder. This was done to ensure
it's always locked last as per the proper glock lock ordering,
and also to pave the way for a future patch in which we will
lock the non-rgrp glocks asynchronously.

Signed-off-by: Bob Peterson <rpeterso at redhat.com>
---
 fs/gfs2/inode.c | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/fs/gfs2/inode.c b/fs/gfs2/inode.c
index 2e2a8a2fb51d..1ced4d0a3b04 100644
--- a/fs/gfs2/inode.c
+++ b/fs/gfs2/inode.c
@@ -1348,7 +1348,7 @@ static int gfs2_rename(struct inode *odir, struct dentry *odentry,
 	struct gfs2_inode *ip = GFS2_I(d_inode(odentry));
 	struct gfs2_inode *nip = NULL;
 	struct gfs2_sbd *sdp = GFS2_SB(odir);
-	struct gfs2_holder ghs[5], r_gh;
+	struct gfs2_holder ghs[4], r_gh, rd_gh;
 	struct gfs2_rgrpd *nrgd;
 	unsigned int num_gh;
 	int dir_rename = 0;
@@ -1357,6 +1357,7 @@ static int gfs2_rename(struct inode *odir, struct dentry *odentry,
 	int error;
 
 	gfs2_holder_mark_uninitialized(&r_gh);
+	gfs2_holder_mark_uninitialized(&rd_gh);
 	if (d_really_is_positive(ndentry)) {
 		nip = GFS2_I(d_inode(ndentry));
 		if (ip == nip)
@@ -1404,7 +1405,8 @@ static int gfs2_rename(struct inode *odir, struct dentry *odentry,
 		 */
 		nrgd = gfs2_blk2rgrpd(sdp, nip->i_no_addr, 1);
 		if (nrgd)
-			gfs2_holder_init(nrgd->rd_gl, LM_ST_EXCLUSIVE, 0, ghs + num_gh++);
+			gfs2_holder_init(nrgd->rd_gl, LM_ST_EXCLUSIVE, 0,
+					 &rd_gh);
 	}
 
 	for (x = 0; x < num_gh; x++) {
@@ -1413,6 +1415,12 @@ static int gfs2_rename(struct inode *odir, struct dentry *odentry,
 			goto out_gunlock;
 	}
 
+	if (gfs2_holder_initialized(&rd_gh)) {
+		error = gfs2_glock_nq(&rd_gh);
+		if (error)
+			goto out_gunlock;
+	}
+
 	error = -ENOENT;
 	if (ip->i_inode.i_nlink == 0)
 		goto out_gunlock;
@@ -1541,6 +1549,9 @@ static int gfs2_rename(struct inode *odir, struct dentry *odentry,
 		gfs2_quota_unlock(ndip);
 out_gunlock:
 	gfs2_dir_no_add(&da);
+	if (gfs2_holder_initialized(&rd_gh))
+		gfs2_glock_dq_uninit(&rd_gh);
+
 	while (x--) {
 		gfs2_glock_dq(ghs + x);
 		gfs2_holder_uninit(ghs + x);
-- 
2.21.0