pnfs: clean up initiate_file_draining layout lookup

Fixes the following compiler warning:

fs/nfs/callback_proc.c: In function 'do_callback_layoutrecall':
fs/nfs/callback_proc.c:115:26: warning: 'lo' may be used uninitialized in this function

Reported-by: Jim Rees <rees@umich.edu>
Signed-off-by: Benny Halevy <bhalevy@tonian.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

diff --git a/fs/nfs/callback_proc.c b/fs/nfs/callback_proc.c
index 54cea8ad5a76ff6f8796030c4f42ad7f70d12ca6..0e6e63f55db4ae9eaa503883ccae4feb3d2a5df6 100644 (file)
--- a/fs/nfs/callback_proc.c
+++ b/fs/nfs/callback_proc.c
@@ -108,42 +108,62 @@ int nfs4_validate_delegation_stateid(struct nfs_delegation *delegation, const nf
 
 #if defined(CONFIG_NFS_V4_1)
 
-static u32 initiate_file_draining(struct nfs_client *clp,
-                                 struct cb_layoutrecallargs *args)
+/*
+ * Lookup a layout by filehandle.
+ *
+ * Note: gets a refcount on the layout hdr and on its respective inode.
+ * Caller must put the layout hdr and the inode.
+ *
+ * TODO: keep track of all layouts (and delegations) in a hash table
+ * hashed by filehandle.
+ */
+static struct pnfs_layout_hdr * get_layout_by_fh_locked(struct nfs_client *clp, struct nfs_fh *fh)
 {
        struct nfs_server *server;
-       struct pnfs_layout_hdr *lo;
        struct inode *ino;
-       bool found = false;
-       u32 rv = NFS4ERR_NOMATCHING_LAYOUT;
-       LIST_HEAD(free_me_list);
+       struct pnfs_layout_hdr *lo;
 
-       spin_lock(&clp->cl_lock);
-       rcu_read_lock();
        list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
                list_for_each_entry(lo, &server->layouts, plh_layouts) {
-                       if (nfs_compare_fh(&args->cbl_fh,
-                                          &NFS_I(lo->plh_inode)->fh))
+                       if (nfs_compare_fh(fh, &NFS_I(lo->plh_inode)->fh))
                                continue;
                        ino = igrab(lo->plh_inode);
                        if (!ino)
                                continue;
-                       found = true;
-                       /* Without this, layout can be freed as soon
-                        * as we release cl_lock.
-                        */
                        get_layout_hdr(lo);
-                       break;
+                       return lo;
                }
-               if (found)
-                       break;
        }
+
+       return NULL;
+}
+
+static struct pnfs_layout_hdr * get_layout_by_fh(struct nfs_client *clp, struct nfs_fh *fh)
+{
+       struct pnfs_layout_hdr *lo;
+
+       spin_lock(&clp->cl_lock);
+       rcu_read_lock();
+       lo = get_layout_by_fh_locked(clp, fh);
        rcu_read_unlock();
        spin_unlock(&clp->cl_lock);
 
-       if (!found)
+       return lo;
+}
+
+static u32 initiate_file_draining(struct nfs_client *clp,
+                                 struct cb_layoutrecallargs *args)
+{
+       struct inode *ino;
+       struct pnfs_layout_hdr *lo;
+       u32 rv = NFS4ERR_NOMATCHING_LAYOUT;
+       LIST_HEAD(free_me_list);
+
+       lo = get_layout_by_fh(clp, &args->cbl_fh);
+       if (!lo)
                return NFS4ERR_NOMATCHING_LAYOUT;
 
+       ino = lo->plh_inode;
        spin_lock(&ino->i_lock);
        if (test_bit(NFS_LAYOUT_BULK_RECALL, &lo->plh_flags) ||
            mark_matching_lsegs_invalid(lo, &free_me_list,