NFS: Clean up nfs_sillyrename()

Optimise for the case where we only do one lookup.
Clean up the code so it is obvious that silly[] is not a dynamic array.

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

diff --git a/fs/nfs/unlink.c b/fs/nfs/unlink.c
index 60395ad..488fd16 100644 (file)
--- a/fs/nfs/unlink.c
+++ b/fs/nfs/unlink.c
@@ -444,6 +444,14 @@ nfs_async_rename(struct inode *old_dir, struct inode *new_dir,
        return rpc_run_task(&task_setup_data);
 }
 
+#define SILLYNAME_PREFIX ".nfs"
+#define SILLYNAME_PREFIX_LEN ((unsigned)sizeof(SILLYNAME_PREFIX) - 1)
+#define SILLYNAME_FILEID_LEN ((unsigned)sizeof(u64) << 1)
+#define SILLYNAME_COUNTER_LEN ((unsigned)sizeof(unsigned int) << 1)
+#define SILLYNAME_LEN (SILLYNAME_PREFIX_LEN + \
+               SILLYNAME_FILEID_LEN + \
+               SILLYNAME_COUNTER_LEN)
+
 /**
  * nfs_sillyrename - Perform a silly-rename of a dentry
  * @dir: inode of directory that contains dentry
@@ -469,10 +477,8 @@ int
 nfs_sillyrename(struct inode *dir, struct dentry *dentry)
 {
        static unsigned int sillycounter;
-       const int      fileidsize  = sizeof(NFS_FILEID(dentry->d_inode))*2;
-       const int      countersize = sizeof(sillycounter)*2;
-       const int      slen        = sizeof(".nfs")+fileidsize+countersize-1;
-       char           silly[slen+1];
+       unsigned char silly[SILLYNAME_LEN + 1];
+       unsigned long long fileid;
        struct dentry *sdentry;
        struct rpc_task *task;
        int            error = -EIO;
@@ -489,20 +495,20 @@ nfs_sillyrename(struct inode *dir, struct dentry *dentry)
        if (dentry->d_flags & DCACHE_NFSFS_RENAMED)
                goto out;
 
-       sprintf(silly, ".nfs%*.*Lx",
-               fileidsize, fileidsize,
-               (unsigned long long)NFS_FILEID(dentry->d_inode));
+       fileid = NFS_FILEID(dentry->d_inode);
 
        /* Return delegation in anticipation of the rename */
        NFS_PROTO(dentry->d_inode)->return_delegation(dentry->d_inode);
 
        sdentry = NULL;
        do {
-               char *suffix = silly + slen - countersize;
-
+               int slen;
                dput(sdentry);
                sillycounter++;
-               sprintf(suffix, "%*.*x", countersize, countersize, sillycounter);
+               slen = scnprintf(silly, sizeof(silly),
+                               SILLYNAME_PREFIX "%0*llx%0*x",
+                               SILLYNAME_FILEID_LEN, fileid,
+                               SILLYNAME_COUNTER_LEN, sillycounter);
 
                dfprintk(VFS, "NFS: trying to rename %s to %s\n",
                                dentry->d_name.name, silly);