NFS: Fix the inode request accounting when pages have subrequests

Both nfs_destroy_unlinked_subrequests() and nfs_lock_and_join_requests()
manipulate the inode flags adjusting the NFS_I(inode)->nrequests.

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

1 files changed, 15 insertions, 12 deletions

diff --git a/fs/nfs/write.c b/fs/nfs/write.c
index bb38c881fc48..ee981353d4aa 100644
--- a/fs/nfs/write.c
+++ b/fs/nfs/write.c
@@ -418,7 +418,8 @@ nfs_unroll_locks_and_wait(struct inode *inode, struct nfs_page *head,
  */
 static void
 nfs_destroy_unlinked_subrequests(struct nfs_page *destroy_list,
-                                 struct nfs_page *old_head)
+                                 struct nfs_page *old_head,
+                                 struct inode *inode)
 {
         while (destroy_list) {
                 struct nfs_page *subreq = destroy_list;
@@ -443,9 +444,12 @@ nfs_destroy_unlinked_subrequests(struct nfs_page *destroy_list,
                         nfs_page_group_clear_bits(subreq);
 
                         /* release the PG_INODE_REF reference */
-                        if (test_and_clear_bit(PG_INODE_REF, &subreq->wb_flags))
+                        if (test_and_clear_bit(PG_INODE_REF, &subreq->wb_flags)) {
                                 nfs_release_request(subreq);
-                        else
+                                spin_lock(&inode->i_lock);
+                                NFS_I(inode)->nrequests--;
+                                spin_unlock(&inode->i_lock);
+                        } else
                                 WARN_ON_ONCE(1);
                 } else {
                         WARN_ON_ONCE(test_bit(PG_CLEAN, &subreq->wb_flags));
@@ -572,25 +576,24 @@ try_again:
                 head->wb_bytes = total_bytes;
         }
 
+        /* Postpone destruction of this request */
+        if (test_and_clear_bit(PG_REMOVE, &head->wb_flags)) {
+                set_bit(PG_INODE_REF, &head->wb_flags);
+                kref_get(&head->wb_kref);
+                NFS_I(inode)->nrequests++;
+        }
+
         /*
          * prepare head request to be added to new pgio descriptor
          */
         nfs_page_group_clear_bits(head);
 
-        /*
-         * some part of the group was still on the inode list - otherwise
-         * the group wouldn't be involved in async write.
-         * grab a reference for the head request, iff it needs one.
-         */
-        if (!test_and_set_bit(PG_INODE_REF, &head->wb_flags))
-                kref_get(&head->wb_kref);
-
         nfs_page_group_unlock(head);
 
         /* drop lock to clean uprequests on destroy list */
         spin_unlock(&inode->i_lock);
 
-        nfs_destroy_unlinked_subrequests(destroy_list, head);
+        nfs_destroy_unlinked_subrequests(destroy_list, head, inode);
 
         /* still holds ref on head from nfs_page_find_head_request_locked
          * and still has lock on head from lock loop */