Commit 49a70f27 authored by Trond Myklebust's avatar Trond Myklebust
Browse files

NFS: Cleanup: add common helper nfs_page_length() 



Clean up a lot of ad-hoc page length calculations in fs/nfs/write.c

Signed-off-by: default avatarTrond Myklebust <Trond.Myklebust@netapp.com>
parent 277459d2

fs/nfs/internal.h

+18 −0
Original line number Diff line number Diff line
@@ -217,3 +217,21 @@ void nfs_super_set_maxbytes(struct super_block *sb, __u64 maxfilesize) 
	if (sb->s_maxbytes > MAX_LFS_FILESIZE || sb->s_maxbytes <= 0)

		sb->s_maxbytes = MAX_LFS_FILESIZE;

}



/*

 * Determine the number of bytes of data the page contains

 */

static inline

unsigned int nfs_page_length(struct page *page)

{

	loff_t i_size = i_size_read(page->mapping->host);



	if (i_size > 0) {

		pgoff_t end_index = (i_size - 1) >> PAGE_CACHE_SHIFT;

		if (page->index < end_index)

			return PAGE_CACHE_SIZE;

		if (page->index == end_index)

			return ((i_size - 1) & ~PAGE_CACHE_MASK) + 1;

	}

	return 0;

}

fs/nfs/read.c

+3 −18
Original line number Diff line number Diff line
@@ -30,6 +30,7 @@ 


#include <asm/system.h>



#include "internal.h"

#include "iostat.h"



#define NFSDBG_FACILITY		NFSDBG_PAGECACHE
@@ -83,22 +84,6 @@ void nfs_readdata_release(void *data) 
        nfs_readdata_free(data);

}



static

unsigned int nfs_page_length(struct inode *inode, struct page *page)

{

	loff_t i_size = i_size_read(inode);

	unsigned long idx;



	if (i_size <= 0)

		return 0;

	idx = (i_size - 1) >> PAGE_CACHE_SHIFT;

	if (page->index > idx)

		return 0;

	if (page->index != idx)

		return PAGE_CACHE_SIZE;

	return 1 + ((i_size - 1) & (PAGE_CACHE_SIZE - 1));

}



static

int nfs_return_empty_page(struct page *page)

{
@@ -231,7 +216,7 @@ static int nfs_readpage_async(struct nfs_open_context *ctx, struct inode *inode, 
	struct nfs_page	*new;

	unsigned int len;



	len = nfs_page_length(inode, page);

	len = nfs_page_length(page);

	if (len == 0)

		return nfs_return_empty_page(page);

	new = nfs_create_request(ctx, inode, page, 0, len);
@@ -667,7 +652,7 @@ readpage_async_filler(void *data, struct page *page) 
	unsigned int len;



	nfs_wb_page(inode, page);

	len = nfs_page_length(inode, page);

	len = nfs_page_length(page);

	if (len == 0)

		return nfs_return_empty_page(page);

	new = nfs_create_request(desc->ctx, inode, page, 0, len);

fs/nfs/write.c

+10 −45
Original line number Diff line number Diff line
@@ -63,6 +63,7 @@ 
#include <linux/smp_lock.h>



#include "delegation.h"

#include "internal.h"

#include "iostat.h"



#define NFSDBG_FACILITY		NFSDBG_PAGECACHE
@@ -199,31 +200,16 @@ static void nfs_grow_file(struct page *page, unsigned int offset, unsigned int c 
 */

static void nfs_mark_uptodate(struct page *page, unsigned int base, unsigned int count)

{

	loff_t end_offs;



	if (PageUptodate(page))

		return;

	if (base != 0)

		return;

	if (count == PAGE_CACHE_SIZE) {

		SetPageUptodate(page);

		return;

	}



	end_offs = i_size_read(page->mapping->host) - 1;

	if (end_offs < 0)

		return;

	/* Is this the last page? */

	if (page->index != (unsigned long)(end_offs >> PAGE_CACHE_SHIFT))

	if (count != nfs_page_length(page))

		return;

	/* This is the last page: set PG_uptodate if we cover the entire

	 * extent of the data, then zero the rest of the page.

	 */

	if (count == (unsigned int)(end_offs & (PAGE_CACHE_SIZE - 1)) + 1) {

	if (count != PAGE_CACHE_SIZE)

		memclear_highpage_flush(page, count, PAGE_CACHE_SIZE - count);

	SetPageUptodate(page);

}

}



/*

 * Write a page synchronously.
@@ -330,9 +316,7 @@ int nfs_writepage(struct page *page, struct writeback_control *wbc) 
{

	struct nfs_open_context *ctx;

	struct inode *inode = page->mapping->host;

	unsigned long end_index;

	unsigned offset = PAGE_CACHE_SIZE;

	loff_t i_size = i_size_read(inode);

	unsigned offset;

	int inode_referenced = 0;

	int priority = wb_priority(wbc);

	int err;
@@ -350,22 +334,15 @@ int nfs_writepage(struct page *page, struct writeback_control *wbc) 
	 */

	if (igrab(inode) != 0)

		inode_referenced = 1;

	end_index = i_size >> PAGE_CACHE_SHIFT;



	/* Ensure we've flushed out any previous writes */

	nfs_wb_page_priority(inode, page, priority);



	/* easy case */

	if (page->index < end_index)

		goto do_it;

	/* things got complicated... */

	offset = i_size & (PAGE_CACHE_SIZE-1);



	/* OK, are we completely out? */

	err = 0; /* potential race with truncate - ignore */

	if (page->index >= end_index+1 || !offset)

	err = 0;

	offset = nfs_page_length(page);

	if (!offset)

		goto out;

do_it:



	ctx = nfs_find_open_context(inode, NULL, FMODE_WRITE);

	if (ctx == NULL) {

		err = -EBADF;
@@ -826,20 +803,8 @@ int nfs_updatepage(struct file *file, struct page *page, 
	 * fragmenting write requests.

	 */

	if (PageUptodate(page) && inode->i_flock == NULL && !(file->f_mode & O_SYNC)) {

		loff_t end_offs = i_size_read(inode) - 1;

		unsigned long end_index = end_offs >> PAGE_CACHE_SHIFT;



		count += offset;

		count = max(count + offset, nfs_page_length(page));

		offset = 0;

		if (unlikely(end_offs < 0)) {

			/* Do nothing */

		} else if (page->index == end_index) {

			unsigned int pglen;

			pglen = (unsigned int)(end_offs & (PAGE_CACHE_SIZE-1)) + 1;

			if (count < pglen)

				count = pglen;

		} else if (page->index < end_index)

			count = PAGE_CACHE_SIZE;

	}



	/*