[linux-2.6-block.git] / 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 <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;
}

/**
 * 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);
}

/**
 * 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;
}

/**
 * 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);
}

/**
 * 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);
}

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;
}

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;
}

/**
 * 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;
}

/**
 * v9fs_direct_IO - 9P address space operation for direct I/O
 * @iocb: target I/O control block
 * @pos: offset in file to begin the operation
 *
 * 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;
}

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;
}

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)) {
		/*
		 * zero out the rest of the area
		 */
		unsigned from = pos & (PAGE_SIZE - 1);

		zero_user(page, from + copied, len - copied);
		flush_dcache_page(page);
	}

	if (!PageUptodate(page))
		SetPageUptodate(page);
	/*
	 * 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);
	unlock_page(page);
	put_page(page);

	return copied;
}


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,
};
Commit	Line	Data
147b31cf EVH	1	/*
	2	* linux/fs/9p/vfs_addr.c
	3	*
	4	* This file contians vfs address (mmap) ops for 9P2000.
	5	*
	6	* Copyright (C) 2005 by Eric Van Hensbergen <ericvh@gmail.com>
	7	* Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
	8	*
	9	* This program is free software; you can redistribute it and/or modify
42e8c509 EVH	10	* it under the terms of the GNU General Public License version 2
42e8c509 EVH	11	* as published by the Free Software Foundation.
147b31cf EVH	12	*
	13	* This program is distributed in the hope that it will be useful,
	14	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	15	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	16	* GNU General Public License for more details.
	17	*
	18	* You should have received a copy of the GNU General Public License
	19	* along with this program; if not, write to:
	20	* Free Software Foundation
	21	* 51 Franklin Street, Fifth Floor
	22	* Boston, MA 02111-1301 USA
	23	*
	24	*/
	25
	26	#include <linux/module.h>
	27	#include <linux/errno.h>
	28	#include <linux/fs.h>
	29	#include <linux/file.h>
	30	#include <linux/stat.h>
	31	#include <linux/string.h>
147b31cf	32	#include <linux/inet.h>
147b31cf EVH	33	#include <linux/pagemap.h>
147b31cf EVH	34	#include <linux/idr.h>
e8edc6e0	35	#include <linux/sched.h>
e2e40f2c	36	#include <linux/uio.h>
bd238fb4 LI	37	#include <net/9p/9p.h>
bd238fb4 LI	38	#include <net/9p/client.h>
147b31cf	39
147b31cf	40	#include "v9fs.h"
147b31cf	41	#include "v9fs_vfs.h"
60e78d2c	42	#include "cache.h"
7263cebe	43	#include "fid.h"
147b31cf EVH	44
147b31cf EVH	45	/**
7263cebe	46	* v9fs_fid_readpage - read an entire page in from 9P
147b31cf	47	*
7263cebe	48	* @fid: fid being read
147b31cf EVH	49	* @page: structure to page
	50	*
	51	*/
7263cebe	52	static int v9fs_fid_readpage(struct p9_fid fid, struct page page)
147b31cf	53	{
e1200fe6 AV	54	struct inode *inode = page->mapping->host;
	55	struct bio_vec bvec = {.bv_page = page, .bv_len = PAGE_SIZE};
	56	struct iov_iter to;
	57	int retval, err;
e03abc0c	58
5d385153	59	p9_debug(P9_DEBUG_VFS, "\n");
60e78d2c AK	60
	61	BUG_ON(!PageLocked(page));
	62
	63	retval = v9fs_readpage_from_fscache(inode, page);
	64	if (retval == 0)
	65	return retval;
	66
e1200fe6	67	iov_iter_bvec(&to, ITER_BVEC \| READ, &bvec, 1, PAGE_SIZE);
147b31cf	68
e1200fe6 AV	69	retval = p9_client_read(fid, page_offset(page), &to, &err);
e1200fe6 AV	70	if (err) {
60e78d2c	71	v9fs_uncache_page(inode, page);
e1200fe6	72	retval = err;
bd238fb4	73	goto done;
60e78d2c	74	}
147b31cf	75
e1200fe6	76	zero_user(page, retval, PAGE_SIZE - retval);
147b31cf EVH	77	flush_dcache_page(page);
147b31cf EVH	78	SetPageUptodate(page);
60e78d2c AK	79
60e78d2c AK	80	v9fs_readpage_to_fscache(inode, page);
147b31cf EVH	81	retval = 0;
147b31cf EVH	82
bd238fb4	83	done:
147b31cf EVH	84	unlock_page(page);
	85	return retval;
	86	}
	87
7263cebe AK	88	/**
	89	* v9fs_vfs_readpage - read an entire page in from 9P
	90	*
	91	* @filp: file being read
	92	* @page: structure to page
	93	*
	94	*/
	95
	96	static int v9fs_vfs_readpage(struct file filp, struct page page)
	97	{
	98	return v9fs_fid_readpage(filp->private_data, page);
	99	}
	100
60e78d2c AK	101	/**
	102	* v9fs_vfs_readpages - read a set of pages from 9P
	103	*
	104	* @filp: file being read
	105	* @mapping: the address space
	106	* @pages: list of pages to read
	107	* @nr_pages: count of pages to read
	108	*
	109	*/
	110
	111	static int v9fs_vfs_readpages(struct file filp, struct address_space mapping,
	112	struct list_head *pages, unsigned nr_pages)
	113	{
	114	int ret = 0;
	115	struct inode *inode;
	116
	117	inode = mapping->host;
5d385153	118	p9_debug(P9_DEBUG_VFS, "inode: %p file: %p\n", inode, filp);
60e78d2c AK	119
	120	ret = v9fs_readpages_from_fscache(inode, mapping, pages, &nr_pages);
	121	if (ret == 0)
	122	return ret;
	123
	124	ret = read_cache_pages(mapping, pages, (void *)v9fs_vfs_readpage, filp);
5d385153	125	p9_debug(P9_DEBUG_VFS, " = %d\n", ret);
60e78d2c AK	126	return ret;
	127	}
	128
	129	/**
	130	* v9fs_release_page - release the private state associated with a page
	131	*
	132	* Returns 1 if the page can be released, false otherwise.
	133	*/
	134
	135	static int v9fs_release_page(struct page *page, gfp_t gfp)
	136	{
	137	if (PagePrivate(page))
	138	return 0;
60e78d2c AK	139	return v9fs_fscache_release_page(page, gfp);
	140	}
	141
	142	/**
	143	* v9fs_invalidate_page - Invalidate a page completely or partially
	144	*
	145	* @page: structure to page
	146	* @offset: offset in the page
	147	*/
	148
d47992f8 LC	149	static void v9fs_invalidate_page(struct page *page, unsigned int offset,
d47992f8 LC	150	unsigned int length)
60e78d2c	151	{
7263cebe AK	152	/*
	153	* If called with zero offset, we should release
	154	* the private state assocated with the page
	155	*/
09cbfeaf	156	if (offset == 0 && length == PAGE_SIZE)
60e78d2c AK	157	v9fs_fscache_invalidate_page(page);
	158	}
	159
7263cebe AK	160	static int v9fs_vfs_writepage_locked(struct page *page)
7263cebe AK	161	{
7263cebe	162	struct inode *inode = page->mapping->host;
371098c6 AV	163	struct v9fs_inode *v9inode = V9FS_I(inode);
	164	loff_t size = i_size_read(inode);
	165	struct iov_iter from;
	166	struct bio_vec bvec;
	167	int err, len;
7263cebe	168
09cbfeaf KS	169	if (page->index == size >> PAGE_SHIFT)
09cbfeaf KS	170	len = size & ~PAGE_MASK;
7263cebe	171	else
09cbfeaf	172	len = PAGE_SIZE;
7263cebe	173
371098c6 AV	174	bvec.bv_page = page;
	175	bvec.bv_offset = 0;
	176	bvec.bv_len = len;
	177	iov_iter_bvec(&from, ITER_BVEC \| WRITE, &bvec, 1, len);
7263cebe	178
6b39f6d2 AK	179	/* We should have writeback_fid always set */
6b39f6d2 AK	180	BUG_ON(!v9inode->writeback_fid);
7263cebe	181
371098c6 AV	182	set_page_writeback(page);
	183
	184	p9_client_write(v9inode->writeback_fid, page_offset(page), &from, &err);
7263cebe	185
7263cebe	186	end_page_writeback(page);
371098c6	187	return err;
7263cebe AK	188	}
	189
	190	static int v9fs_vfs_writepage(struct page page, struct writeback_control wbc)
	191	{
	192	int retval;
	193
fb89b45c DM	194	p9_debug(P9_DEBUG_VFS, "page %p\n", page);
fb89b45c DM	195
7263cebe AK	196	retval = v9fs_vfs_writepage_locked(page);
	197	if (retval < 0) {
	198	if (retval == -EAGAIN) {
	199	redirty_page_for_writepage(wbc, page);
	200	retval = 0;
	201	} else {
	202	SetPageError(page);
	203	mapping_set_error(page->mapping, retval);
	204	}
	205	} else
	206	retval = 0;
	207
	208	unlock_page(page);
	209	return retval;
	210	}
	211
60e78d2c AK	212	/**
60e78d2c AK	213	* v9fs_launder_page - Writeback a dirty page
60e78d2c AK	214	* Returns 0 on success.
	215	*/
	216
	217	static int v9fs_launder_page(struct page *page)
	218	{
7263cebe	219	int retval;
2efda799	220	struct inode *inode = page->mapping->host;
7263cebe	221
2efda799	222	v9fs_fscache_wait_on_page_write(inode, page);
7263cebe AK	223	if (clear_page_dirty_for_io(page)) {
	224	retval = v9fs_vfs_writepage_locked(page);
	225	if (retval)
	226	return retval;
	227	}
60e78d2c AK	228	return 0;
	229	}
	230
3e24ad2f	231	/**
3e24ad2f	232	* v9fs_direct_IO - 9P address space operation for direct I/O
3e24ad2f	233	* @iocb: target I/O control block
3e24ad2f	234	* @pos: offset in file to begin the operation
3e24ad2f	235	*
	236	* The presence of v9fs_direct_IO() in the address space ops vector
	237	* allowes open() O_DIRECT flags which would have failed otherwise.
	238	*
	239	* In the non-cached mode, we shunt off direct read and write requests before
	240	* the VFS gets them, so this method should never be called.
	241	*
	242	* Direct IO is not 'yet' supported in the cached mode. Hence when
	243	* this routine is called through generic_file_aio_read(), the read/write fails
	244	* with an error.
	245	*
	246	*/
e959b549	247	static ssize_t
c8b8e32d	248	v9fs_direct_IO(struct kiocb iocb, struct iov_iter iter)
3e24ad2f	249	{
9565a544	250	struct file *file = iocb->ki_filp;
c8b8e32d	251	loff_t pos = iocb->ki_pos;
42b1ab97 AV	252	ssize_t n;
42b1ab97 AV	253	int err = 0;
6f673763	254	if (iov_iter_rw(iter) == WRITE) {
42b1ab97 AV	255	n = p9_client_write(file->private_data, pos, iter, &err);
42b1ab97 AV	256	if (n) {
9565a544 AV	257	struct inode *inode = file_inode(file);
9565a544 AV	258	loff_t i_size = i_size_read(inode);
42b1ab97 AV	259	if (pos + n > i_size)
42b1ab97 AV	260	inode_add_bytes(inode, pos + n - i_size);
9565a544	261	}
42b1ab97 AV	262	} else {
42b1ab97 AV	263	n = p9_client_read(file->private_data, pos, iter, &err);
9565a544	264	}
42b1ab97	265	return n ? n : err;
3e24ad2f	266	}
7263cebe AK	267
	268	static int v9fs_write_begin(struct file filp, struct address_space mapping,
	269	loff_t pos, unsigned len, unsigned flags,
	270	struct page pagep, void fsdata)
	271	{
	272	int retval = 0;
	273	struct page *page;
6b39f6d2	274	struct v9fs_inode *v9inode;
09cbfeaf	275	pgoff_t index = pos >> PAGE_SHIFT;
7263cebe AK	276	struct inode *inode = mapping->host;
7263cebe AK	277
fb89b45c DM	278
	279	p9_debug(P9_DEBUG_VFS, "filp %p, mapping %p\n", filp, mapping);
	280
6b39f6d2	281	v9inode = V9FS_I(inode);
7263cebe AK	282	start:
	283	page = grab_cache_page_write_begin(mapping, index, flags);
	284	if (!page) {
	285	retval = -ENOMEM;
	286	goto out;
	287	}
6b39f6d2	288	BUG_ON(!v9inode->writeback_fid);
7263cebe AK	289	if (PageUptodate(page))
	290	goto out;
	291
09cbfeaf	292	if (len == PAGE_SIZE)
7263cebe AK	293	goto out;
7263cebe AK	294
6b39f6d2	295	retval = v9fs_fid_readpage(v9inode->writeback_fid, page);
09cbfeaf	296	put_page(page);
7263cebe AK	297	if (!retval)
	298	goto start;
	299	out:
	300	*pagep = page;
	301	return retval;
	302	}
	303
	304	static int v9fs_write_end(struct file filp, struct address_space mapping,
	305	loff_t pos, unsigned len, unsigned copied,
	306	struct page page, void fsdata)
	307	{
	308	loff_t last_pos = pos + copied;
	309	struct inode *inode = page->mapping->host;
	310
fb89b45c DM	311	p9_debug(P9_DEBUG_VFS, "filp %p, mapping %p\n", filp, mapping);
fb89b45c DM	312
7263cebe AK	313	if (unlikely(copied < len)) {
	314	/*
	315	* zero out the rest of the area
	316	*/
09cbfeaf	317	unsigned from = pos & (PAGE_SIZE - 1);
7263cebe AK	318
	319	zero_user(page, from + copied, len - copied);
	320	flush_dcache_page(page);
	321	}
	322
	323	if (!PageUptodate(page))
	324	SetPageUptodate(page);
	325	/*
	326	* No need to use i_size_read() here, the i_size
	327	* cannot change under us because we hold the i_mutex.
	328	*/
	329	if (last_pos > inode->i_size) {
	330	inode_add_bytes(inode, last_pos - inode->i_size);
	331	i_size_write(inode, last_pos);
	332	}
	333	set_page_dirty(page);
	334	unlock_page(page);
09cbfeaf	335	put_page(page);
7263cebe AK	336
	337	return copied;
	338	}
	339
	340
f5e54d6e	341	const struct address_space_operations v9fs_addr_operations = {
7263cebe AK	342	.readpage = v9fs_vfs_readpage,
	343	.readpages = v9fs_vfs_readpages,
	344	.set_page_dirty = __set_page_dirty_nobuffers,
	345	.writepage = v9fs_vfs_writepage,
	346	.write_begin = v9fs_write_begin,
	347	.write_end = v9fs_write_end,
	348	.releasepage = v9fs_release_page,
	349	.invalidatepage = v9fs_invalidate_page,
	350	.launder_page = v9fs_launder_page,
	351	.direct_IO = v9fs_direct_IO,
147b31cf	352	};