gfs2: Lock holder cleanup

Make the code more readable by cleaning up the different ways of
initializing lock holders and checking for initialized lock holders:
mark lock holders as uninitialized by setting the holder's glock to NULL
(gfs2_holder_mark_uninitialized) instead of zeroing out the entire
object or using a separate flag.  Recognize initialized holders by their
non-NULL glock (gfs2_holder_initialized).  Don't zero out holder objects
which are immeditiately initialized via gfs2_holder_init or
gfs2_glock_nq_init.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Bob Peterson <rpeterso@redhat.com>

fs/gfs2/dentry.c

@@ -117,7 +117,7 @@ static int gfs2_dentry_delete(const struct dentry *dentry)
 		return 0;
 
 	ginode = GFS2_I(d_inode(dentry));
-	if (!ginode->i_iopen_gh.gh_gl)
+	if (!gfs2_holder_initialized(&ginode->i_iopen_gh))
 		return 0;
 
 	if (test_bit(GLF_DEMOTE, &ginode->i_iopen_gh.gh_gl->gl_flags))

fs/gfs2/file.c

@@ -1098,7 +1098,7 @@ static void do_unflock(struct file *file, struct file_lock *fl)
 
 	mutex_lock(&fp->f_fl_mutex);
 	locks_lock_file_wait(file, fl);
-	if (fl_gh->gh_gl) {
+	if (gfs2_holder_initialized(fl_gh)) {
 		gfs2_glock_dq(fl_gh);
 		gfs2_holder_uninit(fl_gh);
 	}

fs/gfs2/glock.c

@@ -801,7 +801,7 @@ void gfs2_holder_uninit(struct gfs2_holder *gh)
 {
 	put_pid(gh->gh_owner_pid);
 	gfs2_glock_put(gh->gh_gl);
-	gh->gh_gl = NULL;
+	gfs2_holder_mark_uninitialized(gh);
 	gh->gh_ip = 0;
 }
 

fs/gfs2/glock.h

@@ -247,4 +247,14 @@ extern void gfs2_unregister_debugfs(void);
 
 extern const struct lm_lockops gfs2_dlm_ops;
 
+static inline void gfs2_holder_mark_uninitialized(struct gfs2_holder *gh)
+{
+	gh->gh_gl = NULL;
+}
+
+static inline bool gfs2_holder_initialized(struct gfs2_holder *gh)
+{
+	return gh->gh_gl;
+}
+
 #endif /* __GLOCK_DOT_H__ */

fs/gfs2/inode.c

@@ -127,9 +127,9 @@ struct inode *gfs2_inode_lookup(struct super_block *sb, unsigned int type,
 	struct gfs2_inode *ip;
 	struct gfs2_glock *io_gl = NULL;
 	struct gfs2_holder i_gh;
-	bool unlock = false;
 	int error;
 
+	gfs2_holder_mark_uninitialized(&i_gh);
 	inode = gfs2_iget(sb, no_addr);
 	if (!inode)
 		return ERR_PTR(-ENOMEM);
@@ -159,7 +159,6 @@ struct inode *gfs2_inode_lookup(struct super_block *sb, unsigned int type,
 						   GL_SKIP, &i_gh);
 			if (error)
 				goto fail_put;
-			unlock = true;
 
 			if (blktype != GFS2_BLKST_FREE) {
 				error = gfs2_check_blk_type(sdp, no_addr,
@@ -191,7 +190,7 @@ struct inode *gfs2_inode_lookup(struct super_block *sb, unsigned int type,
 		unlock_new_inode(inode);
 	}
 
-	if (unlock)
+	if (gfs2_holder_initialized(&i_gh))
 		gfs2_glock_dq_uninit(&i_gh);
 	return inode;
 
@@ -203,7 +202,7 @@ fail_refresh:
 fail_put:
 	if (io_gl)
 		gfs2_glock_put(io_gl);
-	if (unlock)
+	if (gfs2_holder_initialized(&i_gh))
 		gfs2_glock_dq_uninit(&i_gh);
 	ip->i_gl->gl_object = NULL;
 fail:
@@ -281,8 +280,8 @@ struct inode *gfs2_lookupi(struct inode *dir, const struct qstr *name,
 	struct gfs2_holder d_gh;
 	int error = 0;
 	struct inode *inode = NULL;
-	int unlock = 0;
 
+	gfs2_holder_mark_uninitialized(&d_gh);
 	if (!name->len || name->len > GFS2_FNAMESIZE)
 		return ERR_PTR(-ENAMETOOLONG);
 
@@ -297,7 +296,6 @@ struct inode *gfs2_lookupi(struct inode *dir, const struct qstr *name,
 		error = gfs2_glock_nq_init(dip->i_gl, LM_ST_SHARED, 0, &d_gh);
 		if (error)
 			return ERR_PTR(error);
-		unlock = 1;
 	}
 
 	if (!is_root) {
@@ -310,7 +308,7 @@ struct inode *gfs2_lookupi(struct inode *dir, const struct qstr *name,
 	if (IS_ERR(inode))
 		error = PTR_ERR(inode);
 out:
-	if (unlock)
+	if (gfs2_holder_initialized(&d_gh))
 		gfs2_glock_dq_uninit(&d_gh);
 	if (error == -ENOENT)
 		return NULL;
@@ -1354,7 +1352,7 @@ 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 = { .gh_gl = NULL, };
+	struct gfs2_holder ghs[5], r_gh;
 	struct gfs2_rgrpd *nrgd;
 	unsigned int num_gh;
 	int dir_rename = 0;
@@ -1362,6 +1360,7 @@ static int gfs2_rename(struct inode *odir, struct dentry *odentry,
 	unsigned int x;
 	int error;
 
+	gfs2_holder_mark_uninitialized(&r_gh);
 	if (d_really_is_positive(ndentry)) {
 		nip = GFS2_I(d_inode(ndentry));
 		if (ip == nip)
@@ -1551,7 +1550,7 @@ out_gunlock:
 		gfs2_holder_uninit(ghs + x);
 	}
 out_gunlock_r:
-	if (r_gh.gh_gl)
+	if (gfs2_holder_initialized(&r_gh))
 		gfs2_glock_dq_uninit(&r_gh);
 out:
 	return error;
@@ -1577,13 +1576,14 @@ static int gfs2_exchange(struct inode *odir, struct dentry *odentry,
 	struct gfs2_inode *oip = GFS2_I(odentry->d_inode);
 	struct gfs2_inode *nip = GFS2_I(ndentry->d_inode);
 	struct gfs2_sbd *sdp = GFS2_SB(odir);
-	struct gfs2_holder ghs[5], r_gh = { .gh_gl = NULL, };
+	struct gfs2_holder ghs[5], r_gh;
 	unsigned int num_gh;
 	unsigned int x;
 	umode_t old_mode = oip->i_inode.i_mode;
 	umode_t new_mode = nip->i_inode.i_mode;
 	int error;
 
+	gfs2_holder_mark_uninitialized(&r_gh);
 	error = gfs2_rindex_update(sdp);
 	if (error)
 		return error;
@@ -1691,7 +1691,7 @@ out_gunlock:
 		gfs2_holder_uninit(ghs + x);
 	}
 out_gunlock_r:
-	if (r_gh.gh_gl)
+	if (gfs2_holder_initialized(&r_gh))
 		gfs2_glock_dq_uninit(&r_gh);
 out:
 	return error;
@@ -1788,9 +1788,8 @@ int gfs2_permission(struct inode *inode, int mask)
 	struct gfs2_inode *ip;
 	struct gfs2_holder i_gh;
 	int error;
-	int unlock = 0;
-
 
+	gfs2_holder_mark_uninitialized(&i_gh);
 	ip = GFS2_I(inode);
 	if (gfs2_glock_is_locked_by_me(ip->i_gl) == NULL) {
 		if (mask & MAY_NOT_BLOCK)
@@ -1798,14 +1797,13 @@ int gfs2_permission(struct inode *inode, int mask)
 		error = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED, LM_FLAG_ANY, &i_gh);
 		if (error)
 			return error;
-		unlock = 1;
 	}
 
 	if ((mask & MAY_WRITE) && IS_IMMUTABLE(inode))
 		error = -EACCES;
 	else
 		error = generic_permission(inode, mask);
-	if (unlock)
+	if (gfs2_holder_initialized(&i_gh))
 		gfs2_glock_dq_uninit(&i_gh);
 
 	return error;
@@ -1977,17 +1975,16 @@ static int gfs2_getattr(struct vfsmount *mnt, struct dentry *dentry,
 	struct gfs2_inode *ip = GFS2_I(inode);
 	struct gfs2_holder gh;
 	int error;
-	int unlock = 0;
 
+	gfs2_holder_mark_uninitialized(&gh);
 	if (gfs2_glock_is_locked_by_me(ip->i_gl) == NULL) {
 		error = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED, LM_FLAG_ANY, &gh);
 		if (error)
 			return error;
-		unlock = 1;
 	}
 
 	generic_fillattr(inode, stat);
-	if (unlock)
+	if (gfs2_holder_initialized(&gh))
 		gfs2_glock_dq_uninit(&gh);
 
 	return 0;

fs/gfs2/main.c

@@ -45,7 +45,7 @@ static void gfs2_init_inode_once(void *foo)
 	memset(&ip->i_res, 0, sizeof(ip->i_res));
 	RB_CLEAR_NODE(&ip->i_res.rs_node);
 	ip->i_hash_cache = NULL;
-	ip->i_iopen_gh.gh_gl = NULL;
+	gfs2_holder_mark_uninitialized(&ip->i_iopen_gh);
 }
 
 static void gfs2_init_glock_once(void *foo)

fs/gfs2/quota.c

@@ -883,7 +883,7 @@ static int do_sync(unsigned int num_qd, struct gfs2_quota_data **qda)
 	gfs2_write_calc_reserv(ip, sizeof(struct gfs2_quota),
 			      &data_blocks, &ind_blocks);
 
-	ghs = kcalloc(num_qd, sizeof(struct gfs2_holder), GFP_NOFS);
+	ghs = kmalloc(num_qd * sizeof(struct gfs2_holder), GFP_NOFS);
 	if (!ghs)
 		return -ENOMEM;
 

fs/gfs2/rgrp.c

@@ -2100,7 +2100,7 @@ void gfs2_inplace_release(struct gfs2_inode *ip)
 {
 	struct gfs2_blkreserv *rs = &ip->i_res;
 
-	if (rs->rs_rgd_gh.gh_gl)
+	if (gfs2_holder_initialized(&rs->rs_rgd_gh))
 		gfs2_glock_dq_uninit(&rs->rs_rgd_gh);
 }
 
@@ -2600,7 +2600,7 @@ void gfs2_rlist_alloc(struct gfs2_rgrp_list *rlist, unsigned int state)
 {
 	unsigned int x;
 
-	rlist->rl_ghs = kcalloc(rlist->rl_rgrps, sizeof(struct gfs2_holder),
+	rlist->rl_ghs = kmalloc(rlist->rl_rgrps * sizeof(struct gfs2_holder),
 				GFP_NOFS | __GFP_NOFAIL);
 	for (x = 0; x < rlist->rl_rgrps; x++)
 		gfs2_holder_init(rlist->rl_rgd[x]->rd_gl,

fs/gfs2/super.c

@@ -855,7 +855,7 @@ static int gfs2_make_fs_ro(struct gfs2_sbd *sdp)
 	wait_event(sdp->sd_reserving_log_wait, atomic_read(&sdp->sd_reserving_log) == 0);
 	gfs2_assert_warn(sdp, atomic_read(&sdp->sd_log_blks_free) == sdp->sd_jdesc->jd_blocks);
 
-	if (freeze_gh.gh_gl)
+	if (gfs2_holder_initialized(&freeze_gh))
 		gfs2_glock_dq_uninit(&freeze_gh);
 
 	gfs2_quota_cleanup(sdp);
@@ -1033,7 +1033,7 @@ static int gfs2_unfreeze(struct super_block *sb)
 
 	mutex_lock(&sdp->sd_freeze_mutex);
         if (atomic_read(&sdp->sd_freeze_state) != SFS_FROZEN ||
-	    sdp->sd_freeze_gh.gh_gl == NULL) {
+	    !gfs2_holder_initialized(&sdp->sd_freeze_gh)) {
 		mutex_unlock(&sdp->sd_freeze_mutex);
                 return 0;
 	}
@@ -1084,9 +1084,11 @@ static int gfs2_statfs_slow(struct gfs2_sbd *sdp, struct gfs2_statfs_change_host
 	int error = 0, err;
 
 	memset(sc, 0, sizeof(struct gfs2_statfs_change_host));
-	gha = kcalloc(slots, sizeof(struct gfs2_holder), GFP_KERNEL);
+	gha = kmalloc(slots * sizeof(struct gfs2_holder), GFP_KERNEL);
 	if (!gha)
 		return -ENOMEM;
+	for (x = 0; x < slots; x++)
+		gfs2_holder_mark_uninitialized(gha + x);
 
 	rgd_next = gfs2_rgrpd_get_first(sdp);
 
@@ -1096,7 +1098,7 @@ static int gfs2_statfs_slow(struct gfs2_sbd *sdp, struct gfs2_statfs_change_host
 		for (x = 0; x < slots; x++) {
 			gh = gha + x;
 
-			if (gh->gh_gl && gfs2_glock_poll(gh)) {
+			if (gfs2_holder_initialized(gh) && gfs2_glock_poll(gh)) {
 				err = gfs2_glock_wait(gh);
 				if (err) {
 					gfs2_holder_uninit(gh);
@@ -1109,7 +1111,7 @@ static int gfs2_statfs_slow(struct gfs2_sbd *sdp, struct gfs2_statfs_change_host
 				}
 			}
 
-			if (gh->gh_gl)
+			if (gfs2_holder_initialized(gh))
 				done = 0;
 			else if (rgd_next && !error) {
 				error = gfs2_glock_nq_init(rgd_next->rd_gl,
@@ -1304,9 +1306,11 @@ static int gfs2_drop_inode(struct inode *inode)
 {
 	struct gfs2_inode *ip = GFS2_I(inode);
 
-	if (!test_bit(GIF_FREE_VFS_INODE, &ip->i_flags) && inode->i_nlink) {
+	if (!test_bit(GIF_FREE_VFS_INODE, &ip->i_flags) &&
+	    inode->i_nlink &&
+	    gfs2_holder_initialized(&ip->i_iopen_gh)) {
 		struct gfs2_glock *gl = ip->i_iopen_gh.gh_gl;
-		if (gl && test_bit(GLF_DEMOTE, &gl->gl_flags))
+		if (test_bit(GLF_DEMOTE, &gl->gl_flags))
 			clear_nlink(inode);
 	}
 	return generic_drop_inode(inode);
@@ -1551,7 +1555,7 @@ static void gfs2_evict_inode(struct inode *inode)
 			goto out_truncate;
 	}
 
-	if (ip->i_iopen_gh.gh_gl &&
+	if (gfs2_holder_initialized(&ip->i_iopen_gh) &&
 	    test_bit(HIF_HOLDER, &ip->i_iopen_gh.gh_iflags)) {
 		ip->i_iopen_gh.gh_flags |= GL_NOCACHE;
 		gfs2_glock_dq_wait(&ip->i_iopen_gh);
@@ -1610,7 +1614,7 @@ out_unlock:
 	if (gfs2_rs_active(&ip->i_res))
 		gfs2_rs_deltree(&ip->i_res);
 
-	if (ip->i_iopen_gh.gh_gl) {
+	if (gfs2_holder_initialized(&ip->i_iopen_gh)) {
 		if (test_bit(HIF_HOLDER, &ip->i_iopen_gh.gh_iflags)) {
 			ip->i_iopen_gh.gh_flags |= GL_NOCACHE;
 			gfs2_glock_dq_wait(&ip->i_iopen_gh);
@@ -1632,7 +1636,7 @@ out:
 	gfs2_glock_add_to_lru(ip->i_gl);
 	gfs2_glock_put(ip->i_gl);
 	ip->i_gl = NULL;
-	if (ip->i_iopen_gh.gh_gl) {
+	if (gfs2_holder_initialized(&ip->i_iopen_gh)) {
 		ip->i_iopen_gh.gh_gl->gl_object = NULL;
 		ip->i_iopen_gh.gh_flags |= GL_NOCACHE;
 		gfs2_glock_dq_wait(&ip->i_iopen_gh);