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>

diff --git a/fs/nfs/write.c b/fs/nfs/write.c
index bb38c881fc488e5a10aa41fc998d18c5a9c8d302..ee981353d4aa110b001a7619f8a324452a001535 100644 (file)
--- 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 */