NFS: Move buffered I/O locking into nfs_file_write()

Preparation for the patch that de-serialises O_DIRECT reads and
writes.

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

diff --git a/fs/nfs/file.c b/fs/nfs/file.c
index c26847c84d0048aaa239efed2cb89203e8b36817..46cf0afe3c0fd7df5907259a75c09a7c936cc6f1 100644 (file)
--- a/fs/nfs/file.c
+++ b/fs/nfs/file.c
@@ -623,7 +623,6 @@ ssize_t nfs_file_write(struct kiocb *iocb, struct iov_iter *from)
        struct inode *inode = file_inode(file);
        unsigned long written = 0;
        ssize_t result;
-       size_t count = iov_iter_count(from);
 
        result = nfs_key_timeout_notify(file, inode);
        if (result)
@@ -633,9 +632,8 @@ ssize_t nfs_file_write(struct kiocb *iocb, struct iov_iter *from)
                return nfs_file_direct_write(iocb, from);
 
        dprintk("NFS: write(%pD2, %zu@%Ld)\n",
-               file, count, (long long) iocb->ki_pos);
+               file, iov_iter_count(from), (long long) iocb->ki_pos);
 
-       result = -EBUSY;
        if (IS_SWAPFILE(inode))
                goto out_swapfile;
        /*
@@ -647,28 +645,33 @@ ssize_t nfs_file_write(struct kiocb *iocb, struct iov_iter *from)
                        goto out;
        }
 
-       result = count;
-       if (!count)
+       inode_lock(inode);
+       result = generic_write_checks(iocb, from);
+       if (result > 0) {
+               current->backing_dev_info = inode_to_bdi(inode);
+               result = generic_perform_write(file, from, iocb->ki_pos);
+               current->backing_dev_info = NULL;
+       }
+       inode_unlock(inode);
+       if (result <= 0)
                goto out;
 
-       result = generic_file_write_iter(iocb, from);
-       if (result > 0)
-               written = result;
+       written = generic_write_sync(iocb, result);
+       iocb->ki_pos += written;
 
        /* Return error values */
-       if (result >= 0 && nfs_need_check_write(file, inode)) {
+       if (nfs_need_check_write(file, inode)) {
                int err = vfs_fsync(file, 0);
                if (err < 0)
                        result = err;
        }
-       if (result > 0)
-               nfs_add_stats(inode, NFSIOS_NORMALWRITTENBYTES, written);
+       nfs_add_stats(inode, NFSIOS_NORMALWRITTENBYTES, written);
 out:
        return result;
 
 out_swapfile:
        printk(KERN_INFO "NFS: attempt to write to active swap file!\n");
-       goto out;
+       return -EBUSY;
 }
 EXPORT_SYMBOL_GPL(nfs_file_write);