NFS: Fix NFS page_state usage

The introduction of the FLUSH_INVALIDATE argument to nfs_sync_inode_wait()
does not clear the nr_unstable page state counter for pages that are being
released.

Also fix a longstanding similar bug when nfs_commit_list() fails.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

1 files changed, 17 insertions, 3 deletions

diff --git a/fs/nfs/write.c b/fs/nfs/write.c
index bca5734ca9fb..86bac6a5008e 100644
--- a/fs/nfs/write.c
+++ b/fs/nfs/write.c
@@ -578,7 +578,7 @@ static int nfs_wait_on_requests(struct inode *inode, unsigned long idx_start, un
         return ret;
 }
 
-static void nfs_cancel_requests(struct list_head *head)
+static void nfs_cancel_dirty_list(struct list_head *head)
 {
         struct nfs_page *req;
         while(!list_empty(head)) {
@@ -589,6 +589,19 @@ static void nfs_cancel_requests(struct list_head *head)
         }
 }
 
+static void nfs_cancel_commit_list(struct list_head *head)
+{
+        struct nfs_page *req;
+
+        while(!list_empty(head)) {
+                req = nfs_list_entry(head->next);
+                nfs_list_remove_request(req);
+                nfs_inode_remove_request(req);
+                nfs_clear_page_writeback(req);
+                dec_zone_page_state(req->wb_page, NR_UNSTABLE_NFS);
+        }
+}
+
 /*
  * nfs_scan_dirty - Scan an inode for dirty requests
  * @inode: NFS inode to scan
@@ -1381,6 +1394,7 @@ nfs_commit_list(struct inode *inode, struct list_head *head, int how)
                 nfs_list_remove_request(req);
                 nfs_mark_request_commit(req);
                 nfs_clear_page_writeback(req);
+                dec_zone_page_state(req->wb_page, NR_UNSTABLE_NFS);
         }
         return -ENOMEM;
 }
@@ -1499,7 +1513,7 @@ int nfs_sync_inode_wait(struct inode *inode, unsigned long idx_start,
                 if (pages != 0) {
                         spin_unlock(&nfsi->req_lock);
                         if (how & FLUSH_INVALIDATE)
-                                nfs_cancel_requests(&head);
+                                nfs_cancel_dirty_list(&head);
                         else
                                 ret = nfs_flush_list(inode, &head, pages, how);
                         spin_lock(&nfsi->req_lock);
@@ -1512,7 +1526,7 @@ int nfs_sync_inode_wait(struct inode *inode, unsigned long idx_start,
                         break;
                 if (how & FLUSH_INVALIDATE) {
                         spin_unlock(&nfsi->req_lock);
-                        nfs_cancel_requests(&head);
+                        nfs_cancel_commit_list(&head);
                         spin_lock(&nfsi->req_lock);
                         continue;
                 }