pnfs: Do not grab the commit_info lock twice when rescheduling writes

Acked-by: Jeff Layton <jlayton@primarydata.com>
Signed-off-by: Tom Haynes <loghyr@primarydata.com>

3 files changed, 23 insertions, 26 deletions

diff --git a/fs/nfs/direct.c b/fs/nfs/direct.c
index 10bf07280f4a..e84f764b9dcd 100644
--- a/fs/nfs/direct.c
+++ b/fs/nfs/direct.c
@@ -573,6 +573,20 @@ out:
         return result;
 }
 
+static void
+nfs_direct_write_scan_commit_list(struct inode *inode,
+                                  struct list_head *list,
+                                  struct nfs_commit_info *cinfo)
+{
+        spin_lock(cinfo->lock);
+#ifdef CONFIG_NFS_V4_1
+        if (cinfo->ds != NULL && cinfo->ds->nwritten != 0)
+                NFS_SERVER(inode)->pnfs_curr_ld->recover_commit_reqs(list, cinfo);
+#endif
+        nfs_scan_commit_list(&cinfo->mds->list, list, cinfo, 0);
+        spin_unlock(cinfo->lock);
+}
+
 static void nfs_direct_write_reschedule(struct nfs_direct_req *dreq)
 {
         struct nfs_pageio_descriptor desc;
@@ -582,10 +596,7 @@ static void nfs_direct_write_reschedule(struct nfs_direct_req *dreq)
         LIST_HEAD(failed);
 
         nfs_init_cinfo_from_dreq(&cinfo, dreq);
-        pnfs_recover_commit_reqs(dreq->inode, &reqs, &cinfo);
-        spin_lock(cinfo.lock);
-        nfs_scan_commit_list(&cinfo.mds->list, &reqs, &cinfo, 0);
-        spin_unlock(cinfo.lock);
+        nfs_direct_write_scan_commit_list(dreq->inode, &reqs, &cinfo);
 
         dreq->count = 0;
         get_dreq(dreq);
diff --git a/fs/nfs/pnfs.h b/fs/nfs/pnfs.h
index f17663446acc..e94f6050e9b1 100644
--- a/fs/nfs/pnfs.h
+++ b/fs/nfs/pnfs.h
@@ -375,15 +375,6 @@ pnfs_scan_commit_lists(struct inode *inode, struct nfs_commit_info *cinfo,
                 return NFS_SERVER(inode)->pnfs_curr_ld->scan_commit_lists(cinfo, max);
 }
 
-static inline void
-pnfs_recover_commit_reqs(struct inode *inode, struct list_head *list,
-                         struct nfs_commit_info *cinfo)
-{
-        if (cinfo->ds == NULL || cinfo->ds->nwritten == 0)
-                return;
-        NFS_SERVER(inode)->pnfs_curr_ld->recover_commit_reqs(list, cinfo);
-}
-
 static inline struct nfs_page *
 pnfs_search_commit_reqs(struct inode *inode, struct nfs_commit_info *cinfo,
                         struct page *page)
@@ -554,12 +545,6 @@ pnfs_scan_commit_lists(struct inode *inode, struct nfs_commit_info *cinfo,
         return 0;
 }
 
-static inline void
-pnfs_recover_commit_reqs(struct inode *inode, struct list_head *list,
-                         struct nfs_commit_info *cinfo)
-{
-}
-
 static inline struct nfs_page *
 pnfs_search_commit_reqs(struct inode *inode, struct nfs_commit_info *cinfo,
                         struct page *page)
diff --git a/fs/nfs/pnfs_nfs.c b/fs/nfs/pnfs_nfs.c
index e5f841cb6227..fd2a2f0e8cbb 100644
--- a/fs/nfs/pnfs_nfs.c
+++ b/fs/nfs/pnfs_nfs.c
@@ -66,7 +66,7 @@ EXPORT_SYMBOL_GPL(pnfs_generic_commit_release);
 
 /* 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 is must be called holding the inode (/cinfo) lock
+ * Note this must be called holding the inode (/cinfo) lock
  */
 void
 pnfs_generic_clear_request_commit(struct nfs_page *req,
@@ -115,7 +115,6 @@ pnfs_generic_transfer_commit_list(struct list_head *src, struct list_head *dst,
         return ret;
 }
 
-/* Note called with cinfo->lock held. */
 static int
 pnfs_generic_scan_ds_commit_list(struct pnfs_commit_bucket *bucket,
                                  struct nfs_commit_info *cinfo,
@@ -125,6 +124,7 @@ pnfs_generic_scan_ds_commit_list(struct pnfs_commit_bucket *bucket,
         struct list_head *dst = &bucket->committing;
         int ret;
 
+        lockdep_assert_held(cinfo->lock);
         ret = pnfs_generic_transfer_commit_list(src, dst, cinfo, max);
         if (ret) {
                 cinfo->ds->nwritten -= ret;
@@ -138,14 +138,15 @@ pnfs_generic_scan_ds_commit_list(struct pnfs_commit_bucket *bucket,
         return ret;
 }
 
-/* Move reqs from written to committing lists, returning count of number moved.
- * Note called with cinfo->lock held.
+/* Move reqs from written to committing lists, returning count
+ * of number moved.
  */
 int pnfs_generic_scan_commit_lists(struct nfs_commit_info *cinfo,
                                    int max)
 {
         int i, rv = 0, cnt;
 
+        lockdep_assert_held(cinfo->lock);
         for (i = 0; i < cinfo->ds->nbuckets && max != 0; i++) {
                 cnt = pnfs_generic_scan_ds_commit_list(&cinfo->ds->buckets[i],
                                                        cinfo, max);
@@ -156,7 +157,7 @@ int pnfs_generic_scan_commit_lists(struct nfs_commit_info *cinfo,
 }
 EXPORT_SYMBOL_GPL(pnfs_generic_scan_commit_lists);
 
-/* Pull everything off the committing lists and dump into @dst */
+/* Pull everything off the committing lists and dump into @dst.  */
 void pnfs_generic_recover_commit_reqs(struct list_head *dst,
                                       struct nfs_commit_info *cinfo)
 {
@@ -164,8 +165,8 @@ void pnfs_generic_recover_commit_reqs(struct list_head *dst,
         struct pnfs_layout_segment *freeme;
         int i;
 
+        lockdep_assert_held(cinfo->lock);
 restart:
-        spin_lock(cinfo->lock);
         for (i = 0, b = cinfo->ds->buckets; i < cinfo->ds->nbuckets; i++, b++) {
                 if (pnfs_generic_transfer_commit_list(&b->written, dst,
                                                       cinfo, 0)) {
@@ -173,11 +174,11 @@ restart:
                         b->wlseg = NULL;
                         spin_unlock(cinfo->lock);
                         pnfs_put_lseg(freeme);
+                        spin_lock(cinfo->lock);
                         goto restart;
                 }
         }
         cinfo->ds->nwritten = 0;
-        spin_unlock(cinfo->lock);
 }
 EXPORT_SYMBOL_GPL(pnfs_generic_recover_commit_reqs);