[Cluster-devel] [PATCH 2/4] gfs2: Protect gl->gl_object by spin lock

[Andreas Gruenbacher <agruenba@redhat.com>]

Put all remaining accesses to gl->gl_object under the
gl->gl_lockref.lock spinlock to prevent races.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
---
 fs/gfs2/bmap.c   |  2 +-
 fs/gfs2/dir.c    |  4 ++--
 fs/gfs2/glops.c  | 17 ++++++++++++++---
 fs/gfs2/incore.h |  2 ++
 fs/gfs2/inode.c  |  8 ++++----
 fs/gfs2/lops.c   |  2 +-
 fs/gfs2/rgrp.c   |  6 ++----
 fs/gfs2/super.c  | 11 +++++++----
 fs/gfs2/xattr.c  |  4 ++--
 9 files changed, 35 insertions(+), 21 deletions(-)

diff --git a/fs/gfs2/bmap.c b/fs/gfs2/bmap.c
index 4d810be..9fa3aef 100644
--- a/fs/gfs2/bmap.c
+++ b/fs/gfs2/bmap.c
@@ -970,7 +970,7 @@ static int sweep_bh_for_rgrps(struct gfs2_inode *ip, struct gfs2_holder *rd_gh,
 			continue;
 		bn = be64_to_cpu(*p);
 		if (gfs2_holder_initialized(rd_gh)) {
-			rgd = (struct gfs2_rgrpd *)rd_gh->gh_gl->gl_object;
+			rgd = gfs2_glock2rgrp(rd_gh->gh_gl);
 			gfs2_assert_withdraw(sdp,
 				     gfs2_glock_is_locked_by_me(rd_gh->gh_gl));
 		} else {
diff --git a/fs/gfs2/dir.c b/fs/gfs2/dir.c
index 7911321..1f5b19d 100644
--- a/fs/gfs2/dir.c
+++ b/fs/gfs2/dir.c
@@ -2031,8 +2031,8 @@ static int leaf_dealloc(struct gfs2_inode *dip, u32 index, u32 len,
 	gfs2_rlist_alloc(&rlist, LM_ST_EXCLUSIVE);
 
 	for (x = 0; x < rlist.rl_rgrps; x++) {
-		struct gfs2_rgrpd *rgd;
-		rgd = rlist.rl_ghs[x].gh_gl->gl_object;
+		struct gfs2_rgrpd *rgd = gfs2_glock2rgrp(rlist.rl_ghs[x].gh_gl);
+
 		rg_blocks += rgd->rd_length;
 	}
 
diff --git a/fs/gfs2/glops.c b/fs/gfs2/glops.c
index 7449b19..5e69636 100644
--- a/fs/gfs2/glops.c
+++ b/fs/gfs2/glops.c
@@ -137,7 +137,7 @@ void gfs2_ail_flush(struct gfs2_glock *gl, bool fsync)
  *
  * Called when demoting or unlocking an EX glock.  We must flush
  * to disk all dirty buffers/pages relating to this glock, and must not
- * not return to caller to demote/unlock the glock until I/O is complete.
+ * return to caller to demote/unlock the glock until I/O is complete.
  */
 
 static void rgrp_go_sync(struct gfs2_glock *gl)
@@ -184,7 +184,7 @@ static void rgrp_go_inval(struct gfs2_glock *gl, int flags)
 {
 	struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
 	struct address_space *mapping = &sdp->sd_aspace;
-	struct gfs2_rgrpd *rgd = gl->gl_object;
+	struct gfs2_rgrpd *rgd = gfs2_glock2rgrp(gl);
 
 	if (rgd)
 		gfs2_rgrp_brelse(rgd);
@@ -209,6 +209,17 @@ static struct gfs2_inode *gfs2_glock2inode(struct gfs2_glock *gl)
 	return ip;
 }
 
+struct gfs2_rgrpd *gfs2_glock2rgrp(struct gfs2_glock *gl)
+{
+	struct gfs2_rgrpd *rgd;
+
+	spin_lock(&gl->gl_lockref.lock);
+	rgd = gl->gl_object;
+	spin_unlock(&gl->gl_lockref.lock);
+
+	return rgd;
+}
+
 static void gfs2_clear_glop_pending(struct gfs2_inode *ip)
 {
 	if (!ip)
@@ -566,7 +577,7 @@ static int freeze_go_demote_ok(const struct gfs2_glock *gl)
  */
 static void iopen_go_callback(struct gfs2_glock *gl, bool remote)
 {
-	struct gfs2_inode *ip = (struct gfs2_inode *)gl->gl_object;
+	struct gfs2_inode *ip = gl->gl_object;
 	struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
 
 	if (!remote || (sdp->sd_vfs->s_flags & MS_RDONLY))
diff --git a/fs/gfs2/incore.h b/fs/gfs2/incore.h
index b6f5b8d..097d83f 100644
--- a/fs/gfs2/incore.h
+++ b/fs/gfs2/incore.h
@@ -859,5 +859,7 @@ static inline void gfs2_sbstats_inc(const struct gfs2_glock *gl, int which)
 	preempt_enable();
 }
 
+extern struct gfs2_rgrpd *gfs2_glock2rgrp(struct gfs2_glock *gl);
+
 #endif /* __INCORE_DOT_H__ */
 
diff --git a/fs/gfs2/inode.c b/fs/gfs2/inode.c
index 912d4e6..50108fa 100644
--- a/fs/gfs2/inode.c
+++ b/fs/gfs2/inode.c
@@ -202,14 +202,14 @@ struct inode *gfs2_inode_lookup(struct super_block *sb, unsigned int type,
 
 fail_refresh:
 	ip->i_iopen_gh.gh_flags |= GL_NOCACHE;
-	ip->i_iopen_gh.gh_gl->gl_object = NULL;
+	glock_set_object(ip->i_iopen_gh.gh_gl, NULL);
 	gfs2_glock_dq_uninit(&ip->i_iopen_gh);
 fail_put:
 	if (io_gl)
 		gfs2_glock_put(io_gl);
 	if (gfs2_holder_initialized(&i_gh))
 		gfs2_glock_dq_uninit(&i_gh);
-	ip->i_gl->gl_object = NULL;
+	glock_set_object(ip->i_gl, NULL);
 fail:
 	iget_failed(inode);
 	return ERR_PTR(error);
@@ -706,7 +706,7 @@ static int gfs2_create_inode(struct inode *dir, struct dentry *dentry,
 	if (error)
 		goto fail_free_inode;
 
-	ip->i_gl->gl_object = ip;
+	glock_set_object(ip->i_gl, ip);
 	error = gfs2_glock_nq_init(ip->i_gl, LM_ST_EXCLUSIVE, GL_SKIP, ghs + 1);
 	if (error)
 		goto fail_free_inode;
@@ -732,7 +732,7 @@ static int gfs2_create_inode(struct inode *dir, struct dentry *dentry,
 	if (error)
 		goto fail_gunlock2;
 
-	ip->i_iopen_gh.gh_gl->gl_object = ip;
+	glock_set_object(ip->i_iopen_gh.gh_gl, ip);
 	gfs2_glock_put(io_gl);
 	gfs2_set_iop(inode);
 	insert_inode_hash(inode);
diff --git a/fs/gfs2/lops.c b/fs/gfs2/lops.c
index b1f9144..b10a69e 100644
--- a/fs/gfs2/lops.c
+++ b/fs/gfs2/lops.c
@@ -71,7 +71,7 @@ static void maybe_release_space(struct gfs2_bufdata *bd)
 {
 	struct gfs2_glock *gl = bd->bd_gl;
 	struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
-	struct gfs2_rgrpd *rgd = gl->gl_object;
+	struct gfs2_rgrpd *rgd = gfs2_glock2rgrp(gl);
 	unsigned int index = bd->bd_bh->b_blocknr - gl->gl_name.ln_number;
 	struct gfs2_bitmap *bi = rgd->rd_bits + index;
 
diff --git a/fs/gfs2/rgrp.c b/fs/gfs2/rgrp.c
index 83c9909..836e38b 100644
--- a/fs/gfs2/rgrp.c
+++ b/fs/gfs2/rgrp.c
@@ -705,9 +705,7 @@ void gfs2_clear_rgrpd(struct gfs2_sbd *sdp)
 		rb_erase(n, &sdp->sd_rindex_tree);
 
 		if (gl) {
-			spin_lock(&gl->gl_lockref.lock);
-			gl->gl_object = NULL;
-			spin_unlock(&gl->gl_lockref.lock);
+			glock_set_object(gl, NULL);
 			gfs2_glock_add_to_lru(gl);
 			gfs2_glock_put(gl);
 		}
@@ -917,7 +915,7 @@ static int read_rindex_entry(struct gfs2_inode *ip)
 	error = rgd_insert(rgd);
 	spin_unlock(&sdp->sd_rindex_spin);
 	if (!error) {
-		rgd->rd_gl->gl_object = rgd;
+		glock_set_object(rgd->rd_gl, rgd);
 		rgd->rd_gl->gl_vm.start = (rgd->rd_addr * bsize) & PAGE_MASK;
 		rgd->rd_gl->gl_vm.end = PAGE_ALIGN((rgd->rd_addr +
 						    rgd->rd_length) * bsize) - 1;
diff --git a/fs/gfs2/super.c b/fs/gfs2/super.c
index 7d12c12..bd5ad6c 100644
--- a/fs/gfs2/super.c
+++ b/fs/gfs2/super.c
@@ -1105,9 +1105,12 @@ static int gfs2_statfs_slow(struct gfs2_sbd *sdp, struct gfs2_statfs_change_host
 					gfs2_holder_uninit(gh);
 					error = err;
 				} else {
-					if (!error)
-						error = statfs_slow_fill(
-							gh->gh_gl->gl_object, sc);
+					if (!error) {
+						struct gfs2_rgrpd *rgd =
+							gfs2_glock2rgrp(gh->gh_gl);
+
+						error = statfs_slow_fill(rgd, sc);
+					}
 					gfs2_glock_dq_uninit(gh);
 				}
 			}
@@ -1637,7 +1640,7 @@ static void gfs2_evict_inode(struct inode *inode)
 	gfs2_glock_put(ip->i_gl);
 	ip->i_gl = NULL;
 	if (gfs2_holder_initialized(&ip->i_iopen_gh)) {
-		ip->i_iopen_gh.gh_gl->gl_object = NULL;
+		glock_set_object(ip->i_iopen_gh.gh_gl, NULL);
 		ip->i_iopen_gh.gh_flags |= GL_NOCACHE;
 		gfs2_glock_dq_uninit(&ip->i_iopen_gh);
 	}
diff --git a/fs/gfs2/xattr.c b/fs/gfs2/xattr.c
index d87721a..5417955 100644
--- a/fs/gfs2/xattr.c
+++ b/fs/gfs2/xattr.c
@@ -1327,8 +1327,8 @@ static int ea_dealloc_indirect(struct gfs2_inode *ip)
 	gfs2_rlist_alloc(&rlist, LM_ST_EXCLUSIVE);
 
 	for (x = 0; x < rlist.rl_rgrps; x++) {
-		struct gfs2_rgrpd *rgd;
-		rgd = rlist.rl_ghs[x].gh_gl->gl_object;
+		struct gfs2_rgrpd *rgd = gfs2_glock2rgrp(rlist.rl_ghs[x].gh_gl);
+
 		rg_blocks += rgd->rd_length;
 	}
 
-- 
2.7.5