NFSv4: Use a mutex to protect the per-inode commit lists

The commit lists can get very large, so using the inode->i_lock can
end up affecting general metadata performance.

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

1 files changed, 12 insertions, 12 deletions

diff --git a/fs/nfs/write.c b/fs/nfs/write.c
index 8d8fa6d4cfcc..5ab5ca24b48a 100644
--- a/fs/nfs/write.c
+++ b/fs/nfs/write.c
@@ -195,7 +195,7 @@ nfs_page_find_swap_request(struct page *page)
         struct nfs_page *req = NULL;
         if (!PageSwapCache(page))
                 return NULL;
-        spin_lock(&inode->i_lock);
+        mutex_lock(&nfsi->commit_mutex);
         if (PageSwapCache(page)) {
                 req = nfs_page_search_commits_for_head_request_locked(nfsi,
                         page);
@@ -204,7 +204,7 @@ nfs_page_find_swap_request(struct page *page)
                         kref_get(&req->wb_kref);
                 }
         }
-        spin_unlock(&inode->i_lock);
+        mutex_unlock(&nfsi->commit_mutex);
         return req;
 }
 
@@ -856,7 +856,8 @@ nfs_page_search_commits_for_head_request_locked(struct nfs_inode *nfsi,
  * number of outstanding requests requiring a commit as well as
  * the MM page stats.
  *
- * The caller must hold cinfo->inode->i_lock, and the nfs_page lock.
+ * The caller must hold NFS_I(cinfo->inode)->commit_mutex, and the
+ * nfs_page lock.
  */
 void
 nfs_request_add_commit_list_locked(struct nfs_page *req, struct list_head *dst,
@@ -884,9 +885,9 @@ EXPORT_SYMBOL_GPL(nfs_request_add_commit_list_locked);
 void
 nfs_request_add_commit_list(struct nfs_page *req, struct nfs_commit_info *cinfo)
 {
-        spin_lock(&cinfo->inode->i_lock);
+        mutex_lock(&NFS_I(cinfo->inode)->commit_mutex);
         nfs_request_add_commit_list_locked(req, &cinfo->mds->list, cinfo);
-        spin_unlock(&cinfo->inode->i_lock);
+        mutex_unlock(&NFS_I(cinfo->inode)->commit_mutex);
         if (req->wb_page)
                 nfs_mark_page_unstable(req->wb_page, cinfo);
 }
@@ -964,11 +965,11 @@ nfs_clear_request_commit(struct nfs_page *req)
                 struct nfs_commit_info cinfo;
 
                 nfs_init_cinfo_from_inode(&cinfo, inode);
-                spin_lock(&inode->i_lock);
+                mutex_lock(&NFS_I(inode)->commit_mutex);
                 if (!pnfs_clear_request_commit(req, &cinfo)) {
                         nfs_request_remove_commit_list(req, &cinfo);
                 }
-                spin_unlock(&inode->i_lock);
+                mutex_unlock(&NFS_I(inode)->commit_mutex);
                 nfs_clear_page_commit(req->wb_page);
         }
 }
@@ -1027,7 +1028,7 @@ nfs_reqs_to_commit(struct nfs_commit_info *cinfo)
         return cinfo->mds->ncommit;
 }
 
-/* cinfo->inode->i_lock held by caller */
+/* NFS_I(cinfo->inode)->commit_mutex held by caller */
 int
 nfs_scan_commit_list(struct list_head *src, struct list_head *dst,
                      struct nfs_commit_info *cinfo, int max)
@@ -1039,13 +1040,12 @@ nfs_scan_commit_list(struct list_head *src, struct list_head *dst,
                 if (!nfs_lock_request(req))
                         continue;
                 kref_get(&req->wb_kref);
-                if (cond_resched_lock(&cinfo->inode->i_lock))
-                        list_safe_reset_next(req, tmp, wb_list);
                 nfs_request_remove_commit_list(req, cinfo);
                 nfs_list_add_request(req, dst);
                 ret++;
                 if ((ret == max) && !cinfo->dreq)
                         break;
+                cond_resched();
         }
         return ret;
 }
@@ -1065,7 +1065,7 @@ nfs_scan_commit(struct inode *inode, struct list_head *dst,
 {
         int ret = 0;
 
-        spin_lock(&cinfo->inode->i_lock);
+        mutex_lock(&NFS_I(cinfo->inode)->commit_mutex);
         if (cinfo->mds->ncommit > 0) {
                 const int max = INT_MAX;
 
@@ -1073,7 +1073,7 @@ nfs_scan_commit(struct inode *inode, struct list_head *dst,
                                            cinfo, max);
                 ret += pnfs_scan_commit_lists(inode, cinfo, max - ret);
         }
-        spin_unlock(&cinfo->inode->i_lock);
+        mutex_unlock(&NFS_I(cinfo->inode)->commit_mutex);
         return ret;
 }