Commit 14a3ec79 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Trond Myklebust
Browse files

nfs: merge nfs_direct_read into nfs_file_direct_read 



Simple code cleanup to prepare for later fixes.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarTrond Myklebust <trond.myklebust@primarydata.com>
parent 1f90ee27

fs/nfs/direct.c

+49 −58
Original line number Diff line number Diff line
@@ -458,14 +458,55 @@ static ssize_t nfs_direct_read_schedule_iovec(struct nfs_direct_req *dreq, 
	return 0;

}



static ssize_t nfs_direct_read(struct kiocb *iocb, const struct iovec *iov,

/**

 * nfs_file_direct_read - file direct read operation for NFS files

 * @iocb: target I/O control block

 * @iov: vector of user buffers into which to read data

 * @nr_segs: size of iov vector

 * @pos: byte offset in file where reading starts

 *

 * We use this function for direct reads instead of calling

 * generic_file_aio_read() in order to avoid gfar's check to see if

 * the request starts before the end of the file.  For that check

 * to work, we must generate a GETATTR before each direct read, and

 * even then there is a window between the GETATTR and the subsequent

 * READ where the file size could change.  Our preference is simply

 * to do all reads the application wants, and the server will take

 * care of managing the end of file boundary.

 *

 * This function also eliminates unnecessarily updating the file's

 * atime locally, as the NFS server sets the file's atime, and this

 * client must read the updated atime from the server back into its

 * cache.

 */

ssize_t nfs_file_direct_read(struct kiocb *iocb, const struct iovec *iov,

				unsigned long nr_segs, loff_t pos, bool uio)

{

	ssize_t result = -ENOMEM;

	struct inode *inode = iocb->ki_filp->f_mapping->host;

	struct file *file = iocb->ki_filp;

	struct address_space *mapping = file->f_mapping;

	struct inode *inode = mapping->host;

	struct nfs_direct_req *dreq;

	struct nfs_lock_context *l_ctx;

	ssize_t result = -EINVAL;

	size_t count;



	count = iov_length(iov, nr_segs);

	nfs_add_stats(mapping->host, NFSIOS_DIRECTREADBYTES, count);



	dfprintk(FILE, "NFS: direct read(%pD2, %zd@%Ld)\n",

		file, count, (long long) pos);



	result = 0;

	if (!count)

		goto out;



	result = nfs_sync_mapping(mapping);

	if (result)

		goto out;



	task_io_account_read(count);



	result = -ENOMEM;

	dreq = nfs_direct_req_alloc();

	if (dreq == NULL)

		goto out;
@@ -484,8 +525,11 @@ static ssize_t nfs_direct_read(struct kiocb *iocb, const struct iovec *iov, 


	NFS_I(inode)->read_io += iov_length(iov, nr_segs);

	result = nfs_direct_read_schedule_iovec(dreq, iov, nr_segs, pos, uio);

	if (!result)

	if (!result) {

		result = nfs_direct_wait(dreq);

		if (result > 0)

			iocb->ki_pos = pos + result;

	}

out_release:

	nfs_direct_req_release(dreq);

out:
@@ -888,59 +932,6 @@ out: 
	return result;

}



/**

 * nfs_file_direct_read - file direct read operation for NFS files

 * @iocb: target I/O control block

 * @iov: vector of user buffers into which to read data

 * @nr_segs: size of iov vector

 * @pos: byte offset in file where reading starts

 *

 * We use this function for direct reads instead of calling

 * generic_file_aio_read() in order to avoid gfar's check to see if

 * the request starts before the end of the file.  For that check

 * to work, we must generate a GETATTR before each direct read, and

 * even then there is a window between the GETATTR and the subsequent

 * READ where the file size could change.  Our preference is simply

 * to do all reads the application wants, and the server will take

 * care of managing the end of file boundary.

 *

 * This function also eliminates unnecessarily updating the file's

 * atime locally, as the NFS server sets the file's atime, and this

 * client must read the updated atime from the server back into its

 * cache.

 */

ssize_t nfs_file_direct_read(struct kiocb *iocb, const struct iovec *iov,

				unsigned long nr_segs, loff_t pos, bool uio)

{

	ssize_t retval = -EINVAL;

	struct file *file = iocb->ki_filp;

	struct address_space *mapping = file->f_mapping;

	size_t count;



	count = iov_length(iov, nr_segs);

	nfs_add_stats(mapping->host, NFSIOS_DIRECTREADBYTES, count);



	dfprintk(FILE, "NFS: direct read(%pD2, %zd@%Ld)\n",

		file, count, (long long) pos);



	retval = 0;

	if (!count)

		goto out;



	retval = nfs_sync_mapping(mapping);

	if (retval)

		goto out;



	task_io_account_read(count);



	retval = nfs_direct_read(iocb, iov, nr_segs, pos, uio);

	if (retval > 0)

		iocb->ki_pos = pos + retval;



out:

	return retval;

}



/**

 * nfs_file_direct_write - file direct write operation for NFS files

 * @iocb: target I/O control block