NFS: Remove unnecessary inode locking in nfs_llseek_dir()

Remove the contentious inode lock, and instead provide thread safety
using the file->f_lock spinlock.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index cb52db9a0cfb7006d2fb31d7c309d615b88a7bbe..e56b1bd99537c64ca72a0b92f28c86ed3d9fd2a7 100644 (file)
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -955,7 +955,6 @@ out:
 
 static loff_t nfs_llseek_dir(struct file *filp, loff_t offset, int whence)
 {
-       struct inode *inode = file_inode(filp);
        struct nfs_open_dir_context *dir_ctx = filp->private_data;
 
        dfprintk(FILE, "NFS: llseek dir(%pD2, %lld, %d)\n",
@@ -967,15 +966,15 @@ static loff_t nfs_llseek_dir(struct file *filp, loff_t offset, int whence)
        case SEEK_SET:
                if (offset < 0)
                        return -EINVAL;
-               inode_lock(inode);
+               spin_lock(&filp->f_lock);
                break;
        case SEEK_CUR:
                if (offset == 0)
                        return filp->f_pos;
-               inode_lock(inode);
+               spin_lock(&filp->f_lock);
                offset += filp->f_pos;
                if (offset < 0) {
-                       inode_unlock(inode);
+                       spin_unlock(&filp->f_lock);
                        return -EINVAL;
                }
        }
@@ -987,7 +986,7 @@ static loff_t nfs_llseek_dir(struct file *filp, loff_t offset, int whence)
                        dir_ctx->dir_cookie = 0;
                dir_ctx->duped = 0;
        }
-       inode_unlock(inode);
+       spin_unlock(&filp->f_lock);
        return offset;
 }