Release 4.11 fs/9p/vfs_addr.c

/*
 *  linux/fs/9p/vfs_addr.c
 *
 * This file contians vfs address (mmap) ops for 9P2000.
 *
 *  Copyright (C) 2005 by Eric Van Hensbergen <ericvh@gmail.com>
 *  Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License version 2
 *  as published by the Free Software Foundation.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to:
 *  Free Software Foundation
 *  51 Franklin Street, Fifth Floor
 *  Boston, MA  02111-1301  USA
 *
 */

#include <linux/module.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/file.h>
#include <linux/stat.h>
#include <linux/string.h>
#include <linux/inet.h>
#include <linux/pagemap.h>
#include <linux/idr.h>
#include <linux/sched.h>
#include <linux/uio.h>
#include <linux/bvec.h>
#include <net/9p/9p.h>
#include <net/9p/client.h>

#include "v9fs.h"
#include "v9fs_vfs.h"
#include "cache.h"
#include "fid.h"

/**
 * v9fs_fid_readpage - read an entire page in from 9P
 *
 * @fid: fid being read
 * @page: structure to page
 *
 */


static int v9fs_fid_readpage(struct p9_fid *fid, struct page *page)
{
	struct inode *inode = page->mapping->host;
	struct bio_vec bvec = {.bv_page = page, .bv_len = PAGE_SIZE};
	struct iov_iter to;
	int retval, err;

	p9_debug(P9_DEBUG_VFS, "\n");

	BUG_ON(!PageLocked(page));

	retval = v9fs_readpage_from_fscache(inode, page);
	if (retval == 0)
		return retval;

	iov_iter_bvec(&to, ITER_BVEC | READ, &bvec, 1, PAGE_SIZE);

	retval = p9_client_read(fid, page_offset(page), &to, &err);
	if (err) {
		v9fs_uncache_page(inode, page);
		retval = err;
		goto done;
	}

	zero_user(page, retval, PAGE_SIZE - retval);
	flush_dcache_page(page);
	SetPageUptodate(page);

	v9fs_readpage_to_fscache(inode, page);
	retval = 0;

done:
	unlock_page(page);
	return retval;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Eric Van Hensbergen
59
32.24%
3
33.33%
Al Viro
59
32.24%
1
11.11%
Abhishek Kulkarni
53
28.96%
2
22.22%
Latchesar Ionkov
7
3.83%
1
11.11%
Aneesh Kumar K.V
4
2.19%
1
11.11%
Joe Perches
1
0.55%
1
11.11%
Total
183
100.00%
9
100.00%

/**
 * v9fs_vfs_readpage - read an entire page in from 9P
 *
 * @filp: file being read
 * @page: structure to page
 *
 */



static int v9fs_vfs_readpage(struct file *filp, struct page *page)
{
	return v9fs_fid_readpage(filp->private_data, page);
}

Contributors
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CommitProp
Aneesh Kumar K.V
26
100.00%
1
100.00%
Total
26
100.00%
1
100.00%

/**
 * v9fs_vfs_readpages - read a set of pages from 9P
 *
 * @filp: file being read
 * @mapping: the address space
 * @pages: list of pages to read
 * @nr_pages: count of pages to read
 *
 */



static int v9fs_vfs_readpages(struct file *filp, struct address_space *mapping,
			     struct list_head *pages, unsigned nr_pages)
{
	int ret = 0;
	struct inode *inode;

	inode = mapping->host;
	p9_debug(P9_DEBUG_VFS, "inode: %p file: %p\n", inode, filp);

	ret = v9fs_readpages_from_fscache(inode, mapping, pages, &nr_pages);
	if (ret == 0)
		return ret;

	ret = read_cache_pages(mapping, pages, (void *)v9fs_vfs_readpage, filp);
	p9_debug(P9_DEBUG_VFS, "  = %d\n", ret);
	return ret;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Abhishek Kulkarni
101
98.06%
1
50.00%
Joe Perches
2
1.94%
1
50.00%
Total
103
100.00%
2
100.00%

/**
 * v9fs_release_page - release the private state associated with a page
 *
 * Returns 1 if the page can be released, false otherwise.
 */



static int v9fs_release_page(struct page *page, gfp_t gfp)
{
	if (PagePrivate(page))
		return 0;
	return v9fs_fscache_release_page(page, gfp);
}

Contributors
Person
Tokens
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Commits
CommitProp
Abhishek Kulkarni
32
100.00%
1
100.00%
Total
32
100.00%
1
100.00%

/**
 * v9fs_invalidate_page - Invalidate a page completely or partially
 *
 * @page: structure to page
 * @offset: offset in the page
 */



static void v9fs_invalidate_page(struct page *page, unsigned int offset,
				 unsigned int length)
{
	/*
         * If called with zero offset, we should release
         * the private state assocated with the page
         */
	if (offset == 0 && length == PAGE_SIZE)
		v9fs_fscache_invalidate_page(page);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Abhishek Kulkarni
25
71.43%
1
25.00%
Lukas Czerner
8
22.86%
1
25.00%
Kirill A. Shutemov
1
2.86%
1
25.00%
Aneesh Kumar K.V
1
2.86%
1
25.00%
Total
35
100.00%
4
100.00%



static int v9fs_vfs_writepage_locked(struct page *page)
{
	struct inode *inode = page->mapping->host;
	struct v9fs_inode *v9inode = V9FS_I(inode);
	loff_t size = i_size_read(inode);
	struct iov_iter from;
	struct bio_vec bvec;
	int err, len;

	if (page->index == size >> PAGE_SHIFT)
		len = size & ~PAGE_MASK;
	else
		len = PAGE_SIZE;

	bvec.bv_page = page;
	bvec.bv_offset = 0;
	bvec.bv_len = len;
	iov_iter_bvec(&from, ITER_BVEC | WRITE, &bvec, 1, len);

	/* We should have writeback_fid always set */
	BUG_ON(!v9inode->writeback_fid);

	set_page_writeback(page);

	p9_client_write(v9inode->writeback_fid, page_offset(page), &from, &err);

	end_page_writeback(page);
	return err;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Aneesh Kumar K.V
75
50.00%
3
50.00%
Al Viro
60
40.00%
1
16.67%
Abhishek Kulkarni
12
8.00%
1
16.67%
Kirill A. Shutemov
3
2.00%
1
16.67%
Total
150
100.00%
6
100.00%



static int v9fs_vfs_writepage(struct page *page, struct writeback_control *wbc)
{
	int retval;

	p9_debug(P9_DEBUG_VFS, "page %p\n", page);

	retval = v9fs_vfs_writepage_locked(page);
	if (retval < 0) {
		if (retval == -EAGAIN) {
			redirty_page_for_writepage(wbc, page);
			retval = 0;
		} else {
			SetPageError(page);
			mapping_set_error(page->mapping, retval);
		}
	} else
		retval = 0;

	unlock_page(page);
	return retval;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Aneesh Kumar K.V
67
72.04%
1
33.33%
Venkateswararao Jujjuri (JV)
17
18.28%
1
33.33%
Dominique Martinet
9
9.68%
1
33.33%
Total
93
100.00%
3
100.00%

/**
 * v9fs_launder_page - Writeback a dirty page
 * Returns 0 on success.
 */



static int v9fs_launder_page(struct page *page)
{
	int retval;
	struct inode *inode = page->mapping->host;

	v9fs_fscache_wait_on_page_write(inode, page);
	if (clear_page_dirty_for_io(page)) {
		retval = v9fs_vfs_writepage_locked(page);
		if (retval)
			return retval;
	}
	return 0;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Aneesh Kumar K.V
58
100.00%
1
100.00%
Total
58
100.00%
1
100.00%

/**
 * v9fs_direct_IO - 9P address space operation for direct I/O
 * @iocb: target I/O control block
 *
 * The presence of v9fs_direct_IO() in the address space ops vector
 * allowes open() O_DIRECT flags which would have failed otherwise.
 *
 * In the non-cached mode, we shunt off direct read and write requests before
 * the VFS gets them, so this method should never be called.
 *
 * Direct IO is not 'yet' supported in the cached mode. Hence when
 * this routine is called through generic_file_aio_read(), the read/write fails
 * with an error.
 *
 */

static ssize_t

v9fs_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
{
	struct file *file = iocb->ki_filp;
	loff_t pos = iocb->ki_pos;
	ssize_t n;
	int err = 0;
	if (iov_iter_rw(iter) == WRITE) {
		n = p9_client_write(file->private_data, pos, iter, &err);
		if (n) {
			struct inode *inode = file_inode(file);
			loff_t i_size = i_size_read(inode);
			if (pos + n > i_size)
				inode_add_bytes(inode, pos + n - i_size);
		}
	} else {
		n = p9_client_read(file->private_data, pos, iter, &err);
	}
	return n ? n : err;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Al Viro
100
73.53%
3
42.86%
Aneesh Kumar K.V
24
17.65%
2
28.57%
Christoph Hellwig
7
5.15%
1
14.29%
Omar Sandoval
5
3.68%
1
14.29%
Total
136
100.00%
7
100.00%



static int v9fs_write_begin(struct file *filp, struct address_space *mapping,
			    loff_t pos, unsigned len, unsigned flags,
			    struct page **pagep, void **fsdata)
{
	int retval = 0;
	struct page *page;
	struct v9fs_inode *v9inode;
	pgoff_t index = pos >> PAGE_SHIFT;
	struct inode *inode = mapping->host;


	p9_debug(P9_DEBUG_VFS, "filp %p, mapping %p\n", filp, mapping);

	v9inode = V9FS_I(inode);
start:
	page = grab_cache_page_write_begin(mapping, index, flags);
	if (!page) {
		retval = -ENOMEM;
		goto out;
	}
	BUG_ON(!v9inode->writeback_fid);
	if (PageUptodate(page))
		goto out;

	if (len == PAGE_SIZE)
		goto out;

	retval = v9fs_fid_readpage(v9inode->writeback_fid, page);
	put_page(page);
	if (!retval)
		goto start;
out:
	*pagep = page;
	return retval;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Aneesh Kumar K.V
160
91.95%
2
50.00%
Dominique Martinet
11
6.32%
1
25.00%
Kirill A. Shutemov
3
1.72%
1
25.00%
Total
174
100.00%
4
100.00%



static int v9fs_write_end(struct file *filp, struct address_space *mapping,
			  loff_t pos, unsigned len, unsigned copied,
			  struct page *page, void *fsdata)
{
	loff_t last_pos = pos + copied;
	struct inode *inode = page->mapping->host;

	p9_debug(P9_DEBUG_VFS, "filp %p, mapping %p\n", filp, mapping);

	if (unlikely(copied < len && !PageUptodate(page))) {
		copied = 0;
		goto out;
	}
	/*
         * No need to use i_size_read() here, the i_size
         * cannot change under us because we hold the i_mutex.
         */
	if (last_pos > inode->i_size) {
		inode_add_bytes(inode, last_pos - inode->i_size);
		i_size_write(inode, last_pos);
	}
	set_page_dirty(page);
out:
	unlock_page(page);
	put_page(page);

	return copied;
}


Contributors
Person
Tokens
Prop
Commits
CommitProp
Aneesh Kumar K.V
112
82.35%
1
25.00%
Al Viro
12
8.82%
1
25.00%
Dominique Martinet
11
8.09%
1
25.00%
Kirill A. Shutemov
1
0.74%
1
25.00%
Total
136
100.00%
4
100.00%


const struct address_space_operations v9fs_addr_operations = {
	.readpage = v9fs_vfs_readpage,
	.readpages = v9fs_vfs_readpages,
	.set_page_dirty = __set_page_dirty_nobuffers,
	.writepage = v9fs_vfs_writepage,
	.write_begin = v9fs_write_begin,
	.write_end = v9fs_write_end,
	.releasepage = v9fs_release_page,
	.invalidatepage = v9fs_invalidate_page,
	.launder_page = v9fs_launder_page,
	.direct_IO = v9fs_direct_IO,
};
Overall Contributors
Person
Tokens
Prop
Commits
CommitProp
Aneesh Kumar K.V
561
45.06%
4
13.79%
Abhishek Kulkarni
249
20.00%
2
6.90%
Al Viro
232
18.63%
7
24.14%
Eric Van Hensbergen
100
8.03%
4
13.79%
Dominique Martinet
31
2.49%
1
3.45%
Venkateswararao Jujjuri (JV)
22
1.77%
1
3.45%
Christoph Hellwig
11
0.88%
3
10.34%
Latchesar Ionkov
10
0.80%
1
3.45%
Kirill A. Shutemov
8
0.64%
1
3.45%
Lukas Czerner
8
0.64%
1
3.45%
Omar Sandoval
5
0.40%
1
3.45%
Alexey Dobriyan
3
0.24%
1
3.45%
Joe Perches
3
0.24%
1
3.45%
Kent Overstreet
2
0.16%
1
3.45%
Total
1245
100.00%
29
100.00%
Directory: fs/9p

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