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>

9 files changed, 46 insertions, 35 deletions

diff --git a/fs/gfs2/dentry.c b/fs/gfs2/dentry.c
index 30822b148f3e..5173b98ca036 100644
--- a/fs/gfs2/dentry.c
+++ b/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))
diff --git a/fs/gfs2/file.c b/fs/gfs2/file.c
index e0f98e483aec..320e65e61938 100644
--- a/fs/gfs2/file.c
+++ b/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);
         }
diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c
index 1138a6131c61..3a90b2b5b9bb 100644
--- a/fs/gfs2/glock.c
+++ b/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;
 }
 
diff --git a/fs/gfs2/glock.h b/fs/gfs2/glock.h
index 46ab67fc16da..ab1ef322f7a5 100644
--- a/fs/gfs2/glock.h
+++ b/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__ */
diff --git a/fs/gfs2/inode.c b/fs/gfs2/inode.c
index 481b6496727d..de54d605cd09 100644
--- a/fs/gfs2/inode.c
+++ b/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;
diff --git a/fs/gfs2/main.c b/fs/gfs2/main.c
index 615f67581cc2..74fd0139e6c2 100644
--- a/fs/gfs2/main.c
+++ b/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)
diff --git a/fs/gfs2/quota.c b/fs/gfs2/quota.c
index ce7d69a2fdc0..6c657b202501 100644
--- a/fs/gfs2/quota.c
+++ b/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;
 
diff --git a/fs/gfs2/rgrp.c b/fs/gfs2/rgrp.c
index 960aaf43d665..fba38ca94135 100644
--- a/fs/gfs2/rgrp.c
+++ b/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,
diff --git a/fs/gfs2/super.c b/fs/gfs2/super.c
index 9b2ff353e45f..3a7e60bb39f8 100644
--- a/fs/gfs2/super.c
+++ b/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);