NFS/pNFS: Simplify bucket layout segment reference counting

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

diff --git a/fs/nfs/pnfs_nfs.c b/fs/nfs/pnfs_nfs.c
index 06df2e6663dc2cc10e0c0e45bf9d9e5655b400d9..abf16fc983464e0d0117d117a50aa2a1cb8788ce 100644 (file)
--- a/fs/nfs/pnfs_nfs.c
+++ b/fs/nfs/pnfs_nfs.c
@@ -59,6 +59,17 @@ void pnfs_generic_commit_release(void *calldata)
 }
 EXPORT_SYMBOL_GPL(pnfs_generic_commit_release);
 
+static struct pnfs_layout_segment *
+pnfs_free_bucket_lseg(struct pnfs_commit_bucket *bucket)
+{
+       if (list_empty(&bucket->committing) && list_empty(&bucket->written)) {
+               struct pnfs_layout_segment *freeme = bucket->lseg;
+               bucket->lseg = NULL;
+               return freeme;
+       }
+       return NULL;
+}
+
 /* The generic layer is about to remove the req from the commit list.
  * If this will make the bucket empty, it will need to put the lseg reference.
  * Note this must be called holding nfsi->commit_mutex
@@ -78,8 +89,7 @@ pnfs_generic_clear_request_commit(struct nfs_page *req,
                bucket = list_first_entry(&req->wb_list,
                                          struct pnfs_commit_bucket,
                                          written);
-               freeme = bucket->wlseg;
-               bucket->wlseg = NULL;
+               freeme = pnfs_free_bucket_lseg(bucket);
        }
 out:
        nfs_request_remove_commit_list(req, cinfo);
@@ -103,8 +113,7 @@ pnfs_alloc_commit_array(size_t n, gfp_t gfp_flags)
        for (b = &p->buckets[0]; n != 0; b++, n--) {
                INIT_LIST_HEAD(&b->written);
                INIT_LIST_HEAD(&b->committing);
-               b->wlseg = NULL;
-               b->clseg = NULL;
+               b->lseg = NULL;
                b->direct_verf.committed = NFS_INVALID_STABLE_HOW;
        }
        return p;
@@ -246,12 +255,6 @@ pnfs_bucket_scan_ds_commit_list(struct pnfs_commit_bucket *bucket,
        if (ret) {
                cinfo->ds->nwritten -= ret;
                cinfo->ds->ncommitting += ret;
-               if (bucket->clseg == NULL)
-                       bucket->clseg = pnfs_get_lseg(bucket->wlseg);
-               if (list_empty(src)) {
-                       pnfs_put_lseg(bucket->wlseg);
-                       bucket->wlseg = NULL;
-               }
        }
        return ret;
 }
@@ -317,9 +320,8 @@ restart:
                if (!nwritten)
                        continue;
                ret += nwritten;
-               if (list_empty(&b->written)) {
-                       freeme = b->wlseg;
-                       b->wlseg = NULL;
+               freeme = pnfs_free_bucket_lseg(b);
+               if (freeme) {
                        pnfs_put_lseg(freeme);
                        goto restart;
                }
@@ -405,15 +407,12 @@ pnfs_bucket_get_committing(struct list_head *head,
                           struct pnfs_commit_bucket *bucket,
                           struct nfs_commit_info *cinfo)
 {
-       struct pnfs_layout_segment *freeme;
        struct list_head *pos;
 
        list_for_each(pos, &bucket->committing)
                cinfo->ds->ncommitting--;
        list_splice_init(&bucket->committing, head);
-       freeme = bucket->clseg;
-       bucket->clseg = NULL;
-       return freeme;
+       return pnfs_free_bucket_lseg(bucket);
 }
 
 static struct nfs_commit_data *
@@ -425,6 +424,8 @@ pnfs_bucket_fetch_commitdata(struct pnfs_commit_bucket *bucket,
        if (!data)
                return NULL;
        data->lseg = pnfs_bucket_get_committing(&data->pages, bucket, cinfo);
+       if (!data->lseg)
+               data->lseg = pnfs_get_lseg(bucket->lseg);
        return data;
 }
 
@@ -1182,8 +1183,8 @@ pnfs_layout_mark_request_commit(struct nfs_page *req,
                 * off due to a rewrite, in which case it will be done in
                 * pnfs_common_clear_request_commit
                 */
-               WARN_ON_ONCE(buckets[ds_commit_idx].wlseg != NULL);
-               buckets[ds_commit_idx].wlseg = pnfs_get_lseg(lseg);
+               if (!buckets[ds_commit_idx].lseg)
+                       buckets[ds_commit_idx].lseg = pnfs_get_lseg(lseg);
        }
        set_bit(PG_COMMIT_TO_DS, &req->wb_flags);
        cinfo->ds->nwritten++;

diff --git a/include/linux/nfs_xdr.h b/include/linux/nfs_xdr.h
index adbbeae9ce5b482fa6bb960e253916d236d944c3..7bbb1f6fc1b1e832383a3ab6c7e984e72a7a78af 100644 (file)
--- a/include/linux/nfs_xdr.h
+++ b/include/linux/nfs_xdr.h
@@ -1265,8 +1265,7 @@ struct nfstime4 {
 struct pnfs_commit_bucket {
        struct list_head written;
        struct list_head committing;
-       struct pnfs_layout_segment *wlseg;
-       struct pnfs_layout_segment *clseg;
+       struct pnfs_layout_segment *lseg;
        struct nfs_writeverf direct_verf;
 };