Re: [Cluster-devel] [GFS2 PATCH v3 10/14] GFS2: Change from tr_touched to tr_bufs

[Steven Whitehouse]

Hi,

On 22/10/15 20:30, Bob Peterson wrote:
This patch changes the GFS2 transaction processing so that it keeps
track of how many buffers are associated with a transaction rather
than whether or not it's been touched. That way, if a buffer is
added, then revoked, then removed entirely, it can avoid some work.
How does this relate to the issue of fixing the unlink/delete code path? 
It looks like this is something that should be a separate patch and not 
part of this series,

Steve.

Signed-off-by: Bob Peterson <rpete...@redhat.com>
---
  fs/gfs2/incore.h  |  5 ++++-
  fs/gfs2/meta_io.c |  6 +++---
  fs/gfs2/trans.c   | 13 +++++++------
  3 files changed, 14 insertions(+), 10 deletions(-)

diff --git a/fs/gfs2/incore.h b/fs/gfs2/incore.h
index 5065e0c..c8f9bb9 100644
--- a/fs/gfs2/incore.h
+++ b/fs/gfs2/incore.h
@@ -473,10 +473,13 @@ struct gfs2_trans {
        unsigned int tr_blocks;
        unsigned int tr_revokes;
        unsigned int tr_reserved;
-       unsigned int tr_touched:1;
        unsigned int tr_attached:1;
        unsigned int tr_alloced:1;
  
+	struct gfs2_holder tr_t_gh;
+
+       int tr_bufs;
+
        unsigned int tr_num_buf_new;
        unsigned int tr_num_databuf_new;
        unsigned int tr_num_buf_rm;
diff --git a/fs/gfs2/meta_io.c b/fs/gfs2/meta_io.c
index 0e1d4be..c20d7ca 100644
--- a/fs/gfs2/meta_io.c
+++ b/fs/gfs2/meta_io.c
@@ -224,7 +224,7 @@ int gfs2_meta_read(struct gfs2_glock *gl, u64 blkno, int 
flags,
        wait_on_buffer(bh);
        if (unlikely(!buffer_uptodate(bh))) {
                struct gfs2_trans *tr = current->journal_info;
-               if (tr && tr->tr_touched)
+               if (tr && tr->tr_bufs)
                        gfs2_io_error_bh(sdp, bh);
                brelse(bh);
                *bhp = NULL;
@@ -251,7 +251,7 @@ int gfs2_meta_wait(struct gfs2_sbd *sdp, struct buffer_head 
*bh)
  
  	if (!buffer_uptodate(bh)) {
                struct gfs2_trans *tr = current->journal_info;
-               if (tr && tr->tr_touched)
+               if (tr && tr->tr_bufs)
                        gfs2_io_error_bh(sdp, bh);
                return -EIO;
        }
@@ -276,7 +276,7 @@ void gfs2_remove_from_journal(struct buffer_head *bh, 
struct gfs2_trans *tr, int
                        tr->tr_num_buf_rm++;
                else
                        tr->tr_num_databuf_rm++;
-               tr->tr_touched = 1;
+               tr->tr_bufs--;
                was_pinned = 1;
                brelse(bh);
        }
diff --git a/fs/gfs2/trans.c b/fs/gfs2/trans.c
index 0c1bde3..25ca935 100644
--- a/fs/gfs2/trans.c
+++ b/fs/gfs2/trans.c
@@ -77,8 +77,8 @@ fail:
  static void gfs2_print_trans(const struct gfs2_trans *tr)
  {
        pr_warn("Transaction created at: %pSR\n", (void *)tr->tr_ip);
-       pr_warn("blocks=%u revokes=%u reserved=%u touched=%u\n",
-               tr->tr_blocks, tr->tr_revokes, tr->tr_reserved, tr->tr_touched);
+       pr_warn("blocks=%u revokes=%u reserved=%u bufs=%d\n",
+               tr->tr_blocks, tr->tr_revokes, tr->tr_reserved, tr->tr_bufs);
        pr_warn("Buf %u/%u Databuf %u/%u Revoke %u/%u\n",
                tr->tr_num_buf_new, tr->tr_num_buf_rm,
                tr->tr_num_databuf_new, tr->tr_num_databuf_rm,
@@ -94,7 +94,7 @@ void gfs2_trans_end(struct gfs2_sbd *sdp)
        BUG_ON(!tr);
        current->journal_info = NULL;
  
-	if (!tr->tr_touched) {
+       if (tr->tr_bufs == 0) {
                gfs2_log_release(sdp, tr->tr_reserved);
                if (alloced) {
                        kfree(tr);
@@ -182,7 +182,7 @@ void gfs2_trans_add_data(struct gfs2_glock *gl, struct 
buffer_head *bh)
                gfs2_log_lock(sdp);
        }
        gfs2_assert(sdp, bd->bd_gl == gl);
-       tr->tr_touched = 1;
+       tr->tr_bufs++;
        if (list_empty(&bd->bd_list)) {
                set_bit(GLF_LFLUSH, &bd->bd_gl->gl_flags);
                set_bit(GLF_DIRTY, &bd->bd_gl->gl_flags);
@@ -201,7 +201,7 @@ static void meta_lo_add(struct gfs2_sbd *sdp, struct 
gfs2_bufdata *bd)
        enum gfs2_freeze_state state = atomic_read(&sdp->sd_freeze_state);
  
  	tr = current->journal_info;
-       tr->tr_touched = 1;
+       tr->tr_bufs++;
        if (!list_empty(&bd->bd_list))
                return;
        set_bit(GLF_LFLUSH, &bd->bd_gl->gl_flags);
@@ -256,7 +256,7 @@ void gfs2_trans_add_revoke(struct gfs2_sbd *sdp, struct 
gfs2_bufdata *bd)
  
  	BUG_ON(!list_empty(&bd->bd_list));
        gfs2_add_revoke(sdp, bd);
-       tr->tr_touched = 1;
+       tr->tr_bufs++;
        tr->tr_num_revoke++;
  }
  
@@ -272,6 +272,7 @@ void gfs2_trans_add_unrevoke(struct gfs2_sbd *sdp, u64 blkno, unsigned int len)
                        list_del_init(&bd->bd_list);
                        gfs2_assert_withdraw(sdp, sdp->sd_log_num_revoke);
                        sdp->sd_log_num_revoke--;
+                       tr->tr_bufs--;
                        kmem_cache_free(gfs2_bufdata_cachep, bd);
                        tr->tr_num_revoke_rm++;
                        if (--n == 0)