GFS2: eliminate log elements and simplify

This patch eliminates the gfs2_log_element data structure and
rolls its two components into the gfs2_bufdata. This makes the code
easier to understand and makes it easier to migrate to a rbtree
to keep the list sorted.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

7 files changed, 48 insertions, 55 deletions

diff --git a/fs/gfs2/aops.c b/fs/gfs2/aops.c
index 695bbe16d1f0..e80a464850c8 100644
--- a/fs/gfs2/aops.c
+++ b/fs/gfs2/aops.c
@@ -942,8 +942,8 @@ static void gfs2_discard(struct gfs2_sbd *sdp, struct buffer_head *bh)
         clear_buffer_dirty(bh);
         bd = bh->b_private;
         if (bd) {
-                if (!list_empty(&bd->bd_le.le_list) && !buffer_pinned(bh))
-                        list_del_init(&bd->bd_le.le_list);
+                if (!list_empty(&bd->bd_list) && !buffer_pinned(bh))
+                        list_del_init(&bd->bd_list);
                 else
                         gfs2_remove_from_journal(bh, current->journal_info, 0);
         }
@@ -1083,9 +1083,9 @@ int gfs2_releasepage(struct page *page, gfp_t gfp_mask)
                 bd = bh->b_private;
                 if (bd) {
                         gfs2_assert_warn(sdp, bd->bd_bh == bh);
-                        if (!list_empty(&bd->bd_le.le_list)) {
+                        if (!list_empty(&bd->bd_list)) {
                                 if (!buffer_pinned(bh))
-                                        list_del_init(&bd->bd_le.le_list);
+                                        list_del_init(&bd->bd_list);
                                 else
                                         bd = NULL;
                         }
diff --git a/fs/gfs2/incore.h b/fs/gfs2/incore.h
index f1189a2cdb78..aa9949e5de26 100644
--- a/fs/gfs2/incore.h
+++ b/fs/gfs2/incore.h
@@ -26,7 +26,7 @@
 #define DIO_METADATA    0x00000020
 
 struct gfs2_log_operations;
-struct gfs2_log_element;
+struct gfs2_bufdata;
 struct gfs2_holder;
 struct gfs2_glock;
 struct gfs2_quota_data;
@@ -52,7 +52,7 @@ struct gfs2_log_header_host {
  */
 
 struct gfs2_log_operations {
-        void (*lo_add) (struct gfs2_sbd *sdp, struct gfs2_log_element *le);
+        void (*lo_add) (struct gfs2_sbd *sdp, struct gfs2_bufdata *bd);
         void (*lo_before_commit) (struct gfs2_sbd *sdp);
         void (*lo_after_commit) (struct gfs2_sbd *sdp, struct gfs2_ail *ai);
         void (*lo_before_scan) (struct gfs2_jdesc *jd,
@@ -64,11 +64,6 @@ struct gfs2_log_operations {
         const char *lo_name;
 };
 
-struct gfs2_log_element {
-        struct list_head le_list;
-        const struct gfs2_log_operations *le_ops;
-};
-
 #define GBF_FULL 1
 
 struct gfs2_bitmap {
@@ -120,7 +115,8 @@ struct gfs2_bufdata {
         struct gfs2_glock *bd_gl;
         u64 bd_blkno;
 
-        struct gfs2_log_element bd_le;
+        struct list_head bd_list;
+        const struct gfs2_log_operations *bd_ops;
 
         struct gfs2_ail *bd_ail;
         struct list_head bd_ail_st_list;
diff --git a/fs/gfs2/log.c b/fs/gfs2/log.c
index db9cb187b6a2..f4beeb9c81c1 100644
--- a/fs/gfs2/log.c
+++ b/fs/gfs2/log.c
@@ -486,8 +486,8 @@ static int bd_cmp(void *priv, struct list_head *a, struct list_head *b)
 {
         struct gfs2_bufdata *bda, *bdb;
 
-        bda = list_entry(a, struct gfs2_bufdata, bd_le.le_list);
-        bdb = list_entry(b, struct gfs2_bufdata, bd_le.le_list);
+        bda = list_entry(a, struct gfs2_bufdata, bd_list);
+        bdb = list_entry(b, struct gfs2_bufdata, bd_list);
 
         if (bda->bd_bh->b_blocknr < bdb->bd_bh->b_blocknr)
                 return -1;
@@ -505,8 +505,8 @@ static void gfs2_ordered_write(struct gfs2_sbd *sdp)
         gfs2_log_lock(sdp);
         list_sort(NULL, &sdp->sd_log_le_ordered, &bd_cmp);
         while (!list_empty(&sdp->sd_log_le_ordered)) {
-                bd = list_entry(sdp->sd_log_le_ordered.next, struct gfs2_bufdata, bd_le.le_list);
-                list_move(&bd->bd_le.le_list, &written);
+                bd = list_entry(sdp->sd_log_le_ordered.next, struct gfs2_bufdata, bd_list);
+                list_move(&bd->bd_list, &written);
                 bh = bd->bd_bh;
                 if (!buffer_dirty(bh))
                         continue;
@@ -533,7 +533,7 @@ static void gfs2_ordered_wait(struct gfs2_sbd *sdp)
 
         gfs2_log_lock(sdp);
         while (!list_empty(&sdp->sd_log_le_ordered)) {
-                bd = list_entry(sdp->sd_log_le_ordered.prev, struct gfs2_bufdata, bd_le.le_list);
+                bd = list_entry(sdp->sd_log_le_ordered.prev, struct gfs2_bufdata, bd_list);
                 bh = bd->bd_bh;
                 if (buffer_locked(bh)) {
                         get_bh(bh);
@@ -543,7 +543,7 @@ static void gfs2_ordered_wait(struct gfs2_sbd *sdp)
                         gfs2_log_lock(sdp);
                         continue;
                 }
-                list_del_init(&bd->bd_le.le_list);
+                list_del_init(&bd->bd_list);
         }
         gfs2_log_unlock(sdp);
 }
diff --git a/fs/gfs2/lops.c b/fs/gfs2/lops.c
index 11fedb569225..852c1be1dd3b 100644
--- a/fs/gfs2/lops.c
+++ b/fs/gfs2/lops.c
@@ -388,9 +388,8 @@ static struct page *gfs2_get_log_desc(struct gfs2_sbd *sdp, u32 ld_type,
         return page;
 }
 
-static void buf_lo_add(struct gfs2_sbd *sdp, struct gfs2_log_element *le)
+static void buf_lo_add(struct gfs2_sbd *sdp, struct gfs2_bufdata *bd)
 {
-        struct gfs2_bufdata *bd = container_of(le, struct gfs2_bufdata, bd_le);
         struct gfs2_meta_header *mh;
         struct gfs2_trans *tr;
 
@@ -398,7 +397,7 @@ static void buf_lo_add(struct gfs2_sbd *sdp, struct gfs2_log_element *le)
         gfs2_log_lock(sdp);
         tr = current->journal_info;
         tr->tr_touched = 1;
-        if (!list_empty(&le->le_list))
+        if (!list_empty(&bd->bd_list))
                 goto out;
         set_bit(GLF_LFLUSH, &bd->bd_gl->gl_flags);
         set_bit(GLF_DIRTY, &bd->bd_gl->gl_flags);
@@ -408,7 +407,7 @@ static void buf_lo_add(struct gfs2_sbd *sdp, struct gfs2_log_element *le)
         mh->__pad0 = cpu_to_be64(0);
         mh->mh_jid = cpu_to_be32(sdp->sd_jdesc->jd_jid);
         sdp->sd_log_num_buf++;
-        list_add(&le->le_list, &sdp->sd_log_le_buf);
+        list_add(&bd->bd_list, &sdp->sd_log_le_buf);
         tr->tr_num_buf_new++;
 out:
         gfs2_log_unlock(sdp);
@@ -440,7 +439,7 @@ static void gfs2_before_commit(struct gfs2_sbd *sdp, unsigned int limit,
         __be64 *ptr;
 
         gfs2_log_lock(sdp);
-        bd1 = bd2 = list_prepare_entry(bd1, blist, bd_le.le_list);
+        bd1 = bd2 = list_prepare_entry(bd1, blist, bd_list);
         while(total) {
                 num = total;
                 if (total > limit)
@@ -452,7 +451,7 @@ static void gfs2_before_commit(struct gfs2_sbd *sdp, unsigned int limit,
                 ptr = (__be64 *)(ld + 1);
 
                 n = 0;
-                list_for_each_entry_continue(bd1, blist, bd_le.le_list) {
+                list_for_each_entry_continue(bd1, blist, bd_list) {
                         *ptr++ = cpu_to_be64(bd1->bd_bh->b_blocknr);
                         if (is_databuf) {
                                 gfs2_check_magic(bd1->bd_bh);
@@ -467,7 +466,7 @@ static void gfs2_before_commit(struct gfs2_sbd *sdp, unsigned int limit,
                 gfs2_log_lock(sdp);
 
                 n = 0;
-                list_for_each_entry_continue(bd2, blist, bd_le.le_list) {
+                list_for_each_entry_continue(bd2, blist, bd_list) {
                         get_bh(bd2->bd_bh);
                         gfs2_log_unlock(sdp);
                         lock_buffer(bd2->bd_bh);
@@ -513,8 +512,8 @@ static void buf_lo_after_commit(struct gfs2_sbd *sdp, struct gfs2_ail *ai)
         struct gfs2_bufdata *bd;
 
         while (!list_empty(head)) {
-                bd = list_entry(head->next, struct gfs2_bufdata, bd_le.le_list);
-                list_del_init(&bd->bd_le.le_list);
+                bd = list_entry(head->next, struct gfs2_bufdata, bd_list);
+                list_del_init(&bd->bd_list);
                 sdp->sd_log_num_buf--;
 
                 gfs2_unpin(sdp, bd->bd_bh, ai);
@@ -601,9 +600,8 @@ static void buf_lo_after_scan(struct gfs2_jdesc *jd, int error, int pass)
                 jd->jd_jid, sdp->sd_replayed_blocks, sdp->sd_found_blocks);
 }
 
-static void revoke_lo_add(struct gfs2_sbd *sdp, struct gfs2_log_element *le)
+static void revoke_lo_add(struct gfs2_sbd *sdp, struct gfs2_bufdata *bd)
 {
-        struct gfs2_bufdata *bd = container_of(le, struct gfs2_bufdata, bd_le);
         struct gfs2_glock *gl = bd->bd_gl;
         struct gfs2_trans *tr;
 
@@ -613,7 +611,7 @@ static void revoke_lo_add(struct gfs2_sbd *sdp, struct gfs2_log_element *le)
         sdp->sd_log_num_revoke++;
         atomic_inc(&gl->gl_revokes);
         set_bit(GLF_LFLUSH, &gl->gl_flags);
-        list_add(&le->le_list, &sdp->sd_log_le_revoke);
+        list_add(&bd->bd_list, &sdp->sd_log_le_revoke);
 }
 
 static void revoke_lo_before_commit(struct gfs2_sbd *sdp)
@@ -634,7 +632,7 @@ static void revoke_lo_before_commit(struct gfs2_sbd *sdp)
         ld = page_address(page);
         offset = sizeof(struct gfs2_log_descriptor);
 
-        list_for_each_entry(bd, head, bd_le.le_list) {
+        list_for_each_entry(bd, head, bd_list) {
                 sdp->sd_log_num_revoke--;
 
                 if (offset + sizeof(u64) > sdp->sd_sb.sb_bsize) {
@@ -664,8 +662,8 @@ static void revoke_lo_after_commit(struct gfs2_sbd *sdp, struct gfs2_ail *ai)
         struct gfs2_glock *gl;
 
         while (!list_empty(head)) {
-                bd = list_entry(head->next, struct gfs2_bufdata, bd_le.le_list);
-                list_del_init(&bd->bd_le.le_list);
+                bd = list_entry(head->next, struct gfs2_bufdata, bd_list);
+                list_del_init(&bd->bd_list);
                 gl = bd->bd_gl;
                 atomic_dec(&gl->gl_revokes);
                 clear_bit(GLF_LFLUSH, &gl->gl_flags);
@@ -768,9 +766,8 @@ static void revoke_lo_after_scan(struct gfs2_jdesc *jd, int error, int pass)
  *    blocks, which isn't an enormous overhead but twice as much as
  *    for normal metadata blocks.
  */
-static void databuf_lo_add(struct gfs2_sbd *sdp, struct gfs2_log_element *le)
+static void databuf_lo_add(struct gfs2_sbd *sdp, struct gfs2_bufdata *bd)
 {
-        struct gfs2_bufdata *bd = container_of(le, struct gfs2_bufdata, bd_le);
         struct gfs2_trans *tr = current->journal_info;
         struct address_space *mapping = bd->bd_bh->b_page->mapping;
         struct gfs2_inode *ip = GFS2_I(mapping->host);
@@ -779,7 +776,7 @@ static void databuf_lo_add(struct gfs2_sbd *sdp, struct gfs2_log_element *le)
         gfs2_log_lock(sdp);
         if (tr)
                 tr->tr_touched = 1;
-        if (!list_empty(&le->le_list))
+        if (!list_empty(&bd->bd_list))
                 goto out;
         set_bit(GLF_LFLUSH, &bd->bd_gl->gl_flags);
         set_bit(GLF_DIRTY, &bd->bd_gl->gl_flags);
@@ -787,9 +784,9 @@ static void databuf_lo_add(struct gfs2_sbd *sdp, struct gfs2_log_element *le)
                 gfs2_pin(sdp, bd->bd_bh);
                 tr->tr_num_databuf_new++;
                 sdp->sd_log_num_databuf++;
-                list_add_tail(&le->le_list, &sdp->sd_log_le_databuf);
+                list_add_tail(&bd->bd_list, &sdp->sd_log_le_databuf);
         } else {
-                list_add_tail(&le->le_list, &sdp->sd_log_le_ordered);
+                list_add_tail(&bd->bd_list, &sdp->sd_log_le_ordered);
         }
 out:
         gfs2_log_unlock(sdp);
@@ -885,8 +882,8 @@ static void databuf_lo_after_commit(struct gfs2_sbd *sdp, struct gfs2_ail *ai)
         struct gfs2_bufdata *bd;
 
         while (!list_empty(head)) {
-                bd = list_entry(head->next, struct gfs2_bufdata, bd_le.le_list);
-                list_del_init(&bd->bd_le.le_list);
+                bd = list_entry(head->next, struct gfs2_bufdata, bd_list);
+                list_del_init(&bd->bd_list);
                 sdp->sd_log_num_databuf--;
                 gfs2_unpin(sdp, bd->bd_bh, ai);
         }
diff --git a/fs/gfs2/lops.h b/fs/gfs2/lops.h
index 825356d9dc14..954a330585f4 100644
--- a/fs/gfs2/lops.h
+++ b/fs/gfs2/lops.h
@@ -46,17 +46,17 @@ static inline unsigned int databuf_limit(struct gfs2_sbd *sdp)
         return limit;
 }
 
-static inline void lops_init_le(struct gfs2_log_element *le,
+static inline void lops_init_le(struct gfs2_bufdata *bd,
                                 const struct gfs2_log_operations *lops)
 {
-        INIT_LIST_HEAD(&le->le_list);
-        le->le_ops = lops;
+        INIT_LIST_HEAD(&bd->bd_list);
+        bd->bd_ops = lops;
 }
 
-static inline void lops_add(struct gfs2_sbd *sdp, struct gfs2_log_element *le)
+static inline void lops_add(struct gfs2_sbd *sdp, struct gfs2_bufdata *bd)
 {
-        if (le->le_ops->lo_add)
-                le->le_ops->lo_add(sdp, le);
+        if (bd->bd_ops->lo_add)
+                bd->bd_ops->lo_add(sdp, bd);
 }
 
 static inline void lops_before_commit(struct gfs2_sbd *sdp)
diff --git a/fs/gfs2/meta_io.c b/fs/gfs2/meta_io.c
index 8a82a4dc711f..7f69ae2595f0 100644
--- a/fs/gfs2/meta_io.c
+++ b/fs/gfs2/meta_io.c
@@ -294,9 +294,9 @@ void gfs2_attach_bufdata(struct gfs2_glock *gl, struct buffer_head *bh,
         bd->bd_gl = gl;
 
         if (meta)
-                lops_init_le(&bd->bd_le, &gfs2_buf_lops);
+                lops_init_le(bd, &gfs2_buf_lops);
         else
-                lops_init_le(&bd->bd_le, &gfs2_databuf_lops);
+                lops_init_le(bd, &gfs2_databuf_lops);
         bh->b_private = bd;
 
         if (meta)
@@ -312,7 +312,7 @@ void gfs2_remove_from_journal(struct buffer_head *bh, struct gfs2_trans *tr, int
         if (test_clear_buffer_pinned(bh)) {
                 trace_gfs2_pin(bd, 0);
                 atomic_dec(&sdp->sd_log_pinned);
-                list_del_init(&bd->bd_le.le_list);
+                list_del_init(&bd->bd_list);
                 if (meta) {
                         gfs2_assert_warn(sdp, sdp->sd_log_num_buf);
                         sdp->sd_log_num_buf--;
diff --git a/fs/gfs2/trans.c b/fs/gfs2/trans.c
index 8fb631769172..ad3e2fb763d7 100644
--- a/fs/gfs2/trans.c
+++ b/fs/gfs2/trans.c
@@ -158,16 +158,16 @@ void gfs2_trans_add_bh(struct gfs2_glock *gl, struct buffer_head *bh, int meta)
                 gfs2_attach_bufdata(gl, bh, meta);
                 bd = bh->b_private;
         }
-        lops_add(sdp, &bd->bd_le);
+        lops_add(sdp, bd);
 }
 
 void gfs2_trans_add_revoke(struct gfs2_sbd *sdp, struct gfs2_bufdata *bd)
 {
-        BUG_ON(!list_empty(&bd->bd_le.le_list));
+        BUG_ON(!list_empty(&bd->bd_list));
         BUG_ON(!list_empty(&bd->bd_ail_st_list));
         BUG_ON(!list_empty(&bd->bd_ail_gl_list));
-        lops_init_le(&bd->bd_le, &gfs2_revoke_lops);
-        lops_add(sdp, &bd->bd_le);
+        lops_init_le(bd, &gfs2_revoke_lops);
+        lops_add(sdp, bd);
 }
 
 void gfs2_trans_add_unrevoke(struct gfs2_sbd *sdp, u64 blkno, unsigned int len)
@@ -177,9 +177,9 @@ void gfs2_trans_add_unrevoke(struct gfs2_sbd *sdp, u64 blkno, unsigned int len)
         unsigned int n = len;
 
         gfs2_log_lock(sdp);
-        list_for_each_entry_safe(bd, tmp, &sdp->sd_log_le_revoke, bd_le.le_list) {
+        list_for_each_entry_safe(bd, tmp, &sdp->sd_log_le_revoke, bd_list) {
                 if ((bd->bd_blkno >= blkno) && (bd->bd_blkno < (blkno + len))) {
-                        list_del_init(&bd->bd_le.le_list);
+                        list_del_init(&bd->bd_list);
                         gfs2_assert_withdraw(sdp, sdp->sd_log_num_revoke);
                         sdp->sd_log_num_revoke--;
                         kmem_cache_free(gfs2_bufdata_cachep, bd);