Commit b8a32e2b authored by Chuck Lever's avatar Chuck Lever Committed by Trond Myklebust
Browse files

NFS: clean up NFS client's a_ops->direct_IO method 



The NFS client's a_ops->direct_IO method, nfs_direct_IO, is required to
be present to allow NFS files to be opened with O_DIRECT, but is never
called because the NFS client shunts reads and writes to files opened
with O_DIRECT directly to its own routines.

Gut the nfs_direct_IO function.  This eliminates the only part of the
NFS client's direct I/O path that requires support for multi-segment
iovs, allowing further simplification in subsequent patches.

Test plan:
Compile the kernel with CONFIG_NFS and CONFIG_NFS_DIRECTIO enabled.  Millions
of fsx-odirect ops.  OraSim.

Signed-off-by: default avatarChuck Lever <cel@netapp.com>
Signed-off-by: default avatarTrond Myklebust <Trond.Myklebust@netapp.com>
parent ec06c096

fs/nfs/direct.c

+23 −47
Original line number Diff line number Diff line
@@ -78,6 +78,29 @@ struct nfs_direct_req { 
};





/**

 * nfs_direct_IO - NFS address space operation for direct I/O

 * @rw: direction (read or write)

 * @iocb: target I/O control block

 * @iov: array of vectors that define I/O buffer

 * @pos: offset in file to begin the operation

 * @nr_segs: size of iovec array

 *

 * The presence of this routine in the address space ops vector means

 * the NFS client supports direct I/O.  However, we shunt off direct

 * read and write requests before the VFS gets them, so this method

 * should never be called.

 */

ssize_t nfs_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov, loff_t pos, unsigned long nr_segs)

{

	struct dentry *dentry = iocb->ki_filp->f_dentry;



	dprintk("NFS: nfs_direct_IO (%s) off/no(%Ld/%lu) EINVAL\n",

			dentry->d_name.name, (long long) pos, nr_segs);



	return -EINVAL;

}



/**

 * nfs_get_user_pages - find and set up pages underlying user's buffer

 * rw: direction (read or write)
@@ -605,53 +628,6 @@ static ssize_t nfs_direct_write(struct inode *inode, 
	return tot_bytes;

}



/**

 * nfs_direct_IO - NFS address space operation for direct I/O

 * rw: direction (read or write)

 * @iocb: target I/O control block

 * @iov: array of vectors that define I/O buffer

 * file_offset: offset in file to begin the operation

 * nr_segs: size of iovec array

 *

 */

ssize_t

nfs_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov,

		loff_t file_offset, unsigned long nr_segs)

{

	ssize_t result = -EINVAL;

	struct file *file = iocb->ki_filp;

	struct nfs_open_context *ctx;

	struct dentry *dentry = file->f_dentry;

	struct inode *inode = dentry->d_inode;



	/*

	 * No support for async yet

	 */

	if (!is_sync_kiocb(iocb))

		return result;



	ctx = (struct nfs_open_context *)file->private_data;

	switch (rw) {

	case READ:

		dprintk("NFS: direct_IO(read) (%s) off/no(%Lu/%lu)\n",

				dentry->d_name.name, file_offset, nr_segs);



		result = nfs_direct_read(inode, ctx, iov,

						file_offset, nr_segs);

		break;

	case WRITE:

		dprintk("NFS: direct_IO(write) (%s) off/no(%Lu/%lu)\n",

				dentry->d_name.name, file_offset, nr_segs);



		result = nfs_direct_write(inode, ctx, iov,

						file_offset, nr_segs);

		break;

	default:

		break;

	}

	return result;

}



/**

 * nfs_file_direct_read - file direct read operation for NFS files

 * @iocb: target I/O control block

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