[mirror_ubuntu-zesty-kernel.git] / fs / afs / file.c

/* AFS filesystem file handling
 *
 * Copyright (C) 2002, 2007 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (dhowells@redhat.com)
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version
 * 2 of the License, or (at your option) any later version.
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/fs.h>
#include <linux/pagemap.h>
#include <linux/writeback.h>
#include "internal.h"

static int afs_readpage(struct file *file, struct page *page);
static void afs_invalidatepage(struct page *page, unsigned long offset);
static int afs_releasepage(struct page *page, gfp_t gfp_flags);
static int afs_launder_page(struct page *page);

static int afs_readpages(struct file *filp, struct address_space *mapping,
			 struct list_head *pages, unsigned nr_pages);

const struct file_operations afs_file_operations = {
	.open		= afs_open,
	.release	= afs_release,
	.llseek		= generic_file_llseek,
	.read		= do_sync_read,
	.write		= do_sync_write,
	.aio_read	= generic_file_aio_read,
	.aio_write	= afs_file_write,
	.mmap		= generic_file_readonly_mmap,
	.splice_read	= generic_file_splice_read,
	.fsync		= afs_fsync,
	.lock		= afs_lock,
	.flock		= afs_flock,
};

const struct inode_operations afs_file_inode_operations = {
	.getattr	= afs_getattr,
	.setattr	= afs_setattr,
	.permission	= afs_permission,
};

const struct address_space_operations afs_fs_aops = {
	.readpage	= afs_readpage,
	.readpages	= afs_readpages,
	.set_page_dirty	= afs_set_page_dirty,
	.launder_page	= afs_launder_page,
	.releasepage	= afs_releasepage,
	.invalidatepage	= afs_invalidatepage,
	.write_begin	= afs_write_begin,
	.write_end	= afs_write_end,
	.writepage	= afs_writepage,
	.writepages	= afs_writepages,
};

/*
 * open an AFS file or directory and attach a key to it
 */
int afs_open(struct inode *inode, struct file *file)
{
	struct afs_vnode *vnode = AFS_FS_I(inode);
	struct key *key;
	int ret;

	_enter("{%x:%u},", vnode->fid.vid, vnode->fid.vnode);

	key = afs_request_key(vnode->volume->cell);
	if (IS_ERR(key)) {
		_leave(" = %ld [key]", PTR_ERR(key));
		return PTR_ERR(key);
	}

	ret = afs_validate(vnode, key);
	if (ret < 0) {
		_leave(" = %d [val]", ret);
		return ret;
	}

	file->private_data = key;
	_leave(" = 0");
	return 0;
}

/*
 * release an AFS file or directory and discard its key
 */
int afs_release(struct inode *inode, struct file *file)
{
	struct afs_vnode *vnode = AFS_FS_I(inode);

	_enter("{%x:%u},", vnode->fid.vid, vnode->fid.vnode);

	key_put(file->private_data);
	_leave(" = 0");
	return 0;
}

/*
 * deal with notification that a page was read from the cache
 */
static void afs_file_readpage_read_complete(struct page *page,
					    void *data,
					    int error)
{
	_enter("%p,%p,%d", page, data, error);

	/* if the read completes with an error, we just unlock the page and let
	 * the VM reissue the readpage */
	if (!error)
		SetPageUptodate(page);
	unlock_page(page);
}

/*
 * AFS read page from file, directory or symlink
 */
static int afs_readpage(struct file *file, struct page *page)
{
	struct afs_vnode *vnode;
	struct inode *inode;
	struct key *key;
	size_t len;
	off_t offset;
	int ret;

	inode = page->mapping->host;

	ASSERT(file != NULL);
	key = file->private_data;
	ASSERT(key != NULL);

	_enter("{%x},{%lu},{%lu}", key_serial(key), inode->i_ino, page->index);

	vnode = AFS_FS_I(inode);

	BUG_ON(!PageLocked(page));

	ret = -ESTALE;
	if (test_bit(AFS_VNODE_DELETED, &vnode->flags))
		goto error;

	/* is it cached? */
#ifdef CONFIG_AFS_FSCACHE
	ret = fscache_read_or_alloc_page(vnode->cache,
					 page,
					 afs_file_readpage_read_complete,
					 NULL,
					 GFP_KERNEL);
#else
	ret = -ENOBUFS;
#endif
	switch (ret) {
		/* read BIO submitted (page in cache) */
	case 0:
		break;

		/* page not yet cached */
	case -ENODATA:
		_debug("cache said ENODATA");
		goto go_on;

		/* page will not be cached */
	case -ENOBUFS:
		_debug("cache said ENOBUFS");
	default:
	go_on:
		offset = page->index << PAGE_CACHE_SHIFT;
		len = min_t(size_t, i_size_read(inode) - offset, PAGE_SIZE);

		/* read the contents of the file from the server into the
		 * page */
		ret = afs_vnode_fetch_data(vnode, key, offset, len, page);
		if (ret < 0) {
			if (ret == -ENOENT) {
				_debug("got NOENT from server"
				       " - marking file deleted and stale");
				set_bit(AFS_VNODE_DELETED, &vnode->flags);
				ret = -ESTALE;
			}

#ifdef CONFIG_AFS_FSCACHE
			fscache_uncache_page(vnode->cache, page);
#endif
			BUG_ON(PageFsCache(page));
			goto error;
		}

		SetPageUptodate(page);

		/* send the page to the cache */
#ifdef CONFIG_AFS_FSCACHE
		if (PageFsCache(page) &&
		    fscache_write_page(vnode->cache, page, GFP_KERNEL) != 0) {
			fscache_uncache_page(vnode->cache, page);
			BUG_ON(PageFsCache(page));
		}
#endif
		unlock_page(page);
	}

	_leave(" = 0");
	return 0;

error:
	SetPageError(page);
	unlock_page(page);
	_leave(" = %d", ret);
	return ret;
}

/*
 * read a set of pages
 */
static int afs_readpages(struct file *file, struct address_space *mapping,
			 struct list_head *pages, unsigned nr_pages)
{
	struct afs_vnode *vnode;
	int ret = 0;

	_enter(",{%lu},,%d", mapping->host->i_ino, nr_pages);

	vnode = AFS_FS_I(mapping->host);
	if (vnode->flags & AFS_VNODE_DELETED) {
		_leave(" = -ESTALE");
		return -ESTALE;
	}

	/* attempt to read as many of the pages as possible */
#ifdef CONFIG_AFS_FSCACHE
	ret = fscache_read_or_alloc_pages(vnode->cache,
					  mapping,
					  pages,
					  &nr_pages,
					  afs_file_readpage_read_complete,
					  NULL,
					  mapping_gfp_mask(mapping));
#else
	ret = -ENOBUFS;
#endif

	switch (ret) {
		/* all pages are being read from the cache */
	case 0:
		BUG_ON(!list_empty(pages));
		BUG_ON(nr_pages != 0);
		_leave(" = 0 [reading all]");
		return 0;

		/* there were pages that couldn't be read from the cache */
	case -ENODATA:
	case -ENOBUFS:
		break;

		/* other error */
	default:
		_leave(" = %d", ret);
		return ret;
	}

	/* load the missing pages from the network */
	ret = read_cache_pages(mapping, pages, (void *) afs_readpage, file);

	_leave(" = %d [netting]", ret);
	return ret;
}

/*
 * write back a dirty page
 */
static int afs_launder_page(struct page *page)
{
	_enter("{%lu}", page->index);

	return 0;
}

/*
 * invalidate part or all of a page
 * - release a page and clean up its private data if offset is 0 (indicating
 *   the entire page)
 */
static void afs_invalidatepage(struct page *page, unsigned long offset)
{
	struct afs_writeback *wb = (struct afs_writeback *) page_private(page);

	_enter("{%lu},%lu", page->index, offset);

	BUG_ON(!PageLocked(page));

	/* we clean up only if the entire page is being invalidated */
	if (offset == 0) {
#ifdef CONFIG_AFS_FSCACHE
		if (PageFsCache(page)) {
			struct afs_vnode *vnode = AFS_FS_I(page->mapping->host);
			fscache_wait_on_page_write(vnode->cache, page);
			fscache_uncache_page(vnode->cache, page);
			ClearPageFsCache(page);
		}
#endif

		if (PagePrivate(page)) {
			if (wb && !PageWriteback(page)) {
				set_page_private(page, 0);
				afs_put_writeback(wb);
			}

			if (!page_private(page))
				ClearPagePrivate(page);
		}
	}

	_leave("");
}

/*
 * release a page and clean up its private state if it's not busy
 * - return true if the page can now be released, false if not
 */
static int afs_releasepage(struct page *page, gfp_t gfp_flags)
{
	struct afs_writeback *wb = (struct afs_writeback *) page_private(page);
	struct afs_vnode *vnode = AFS_FS_I(page->mapping->host);

	_enter("{{%x:%u}[%lu],%lx},%x",
	       vnode->fid.vid, vnode->fid.vnode, page->index, page->flags,
	       gfp_flags);

	/* deny if page is being written to the cache and the caller hasn't
	 * elected to wait */
#ifdef CONFIG_AFS_FSCACHE
	if (PageFsCache(page)) {
		if (fscache_check_page_write(vnode->cache, page)) {
			if (!(gfp_flags & __GFP_WAIT)) {
				_leave(" = F [cache busy]");
				return 0;
			}
			fscache_wait_on_page_write(vnode->cache, page);
		}

		fscache_uncache_page(vnode->cache, page);
		ClearPageFsCache(page);
	}
#endif

	if (PagePrivate(page)) {
		if (wb) {
			set_page_private(page, 0);
			afs_put_writeback(wb);
		}
		ClearPagePrivate(page);
	}

	/* indicate that the page can be released */
	_leave(" = T");
	return 1;
}
Commit	Line	Data
08e0e7c8	1	/* AFS filesystem file handling
1da177e4	2	*
08e0e7c8	3	* Copyright (C) 2002, 2007 Red Hat, Inc. All Rights Reserved.
1da177e4 LT	4	* Written by David Howells (dhowells@redhat.com)
	5	*
	6	* This program is free software; you can redistribute it and/or
	7	* modify it under the terms of the GNU General Public License
	8	* as published by the Free Software Foundation; either version
	9	* 2 of the License, or (at your option) any later version.
	10	*/
	11
	12	#include <linux/kernel.h>
	13	#include <linux/module.h>
	14	#include <linux/init.h>
1da177e4 LT	15	#include <linux/slab.h>
	16	#include <linux/fs.h>
	17	#include <linux/pagemap.h>
31143d5d	18	#include <linux/writeback.h>
1da177e4 LT	19	#include "internal.h"
1da177e4 LT	20
416351f2 DH	21	static int afs_readpage(struct file file, struct page page);
	22	static void afs_invalidatepage(struct page *page, unsigned long offset);
	23	static int afs_releasepage(struct page *page, gfp_t gfp_flags);
31143d5d	24	static int afs_launder_page(struct page *page);
1da177e4	25
9b3f26c9 DH	26	static int afs_readpages(struct file filp, struct address_space mapping,
	27	struct list_head *pages, unsigned nr_pages);
	28
00d3b7a4 DH	29	const struct file_operations afs_file_operations = {
	30	.open = afs_open,
	31	.release = afs_release,
	32	.llseek = generic_file_llseek,
	33	.read = do_sync_read,
31143d5d	34	.write = do_sync_write,
00d3b7a4	35	.aio_read = generic_file_aio_read,
31143d5d	36	.aio_write = afs_file_write,
00d3b7a4	37	.mmap = generic_file_readonly_mmap,
5ffc4ef4	38	.splice_read = generic_file_splice_read,
31143d5d	39	.fsync = afs_fsync,
e8d6c554 DH	40	.lock = afs_lock,
e8d6c554 DH	41	.flock = afs_flock,
00d3b7a4 DH	42	};
00d3b7a4 DH	43
754661f1	44	const struct inode_operations afs_file_inode_operations = {
416351f2	45	.getattr = afs_getattr,
31143d5d	46	.setattr = afs_setattr,
00d3b7a4	47	.permission = afs_permission,
1da177e4 LT	48	};
1da177e4 LT	49
f5e54d6e	50	const struct address_space_operations afs_fs_aops = {
416351f2	51	.readpage = afs_readpage,
9b3f26c9	52	.readpages = afs_readpages,
31143d5d DH	53	.set_page_dirty = afs_set_page_dirty,
31143d5d DH	54	.launder_page = afs_launder_page,
416351f2 DH	55	.releasepage = afs_releasepage,
416351f2 DH	56	.invalidatepage = afs_invalidatepage,
15b4650e NP	57	.write_begin = afs_write_begin,
15b4650e NP	58	.write_end = afs_write_end,
31143d5d DH	59	.writepage = afs_writepage,
31143d5d DH	60	.writepages = afs_writepages,
1da177e4 LT	61	};
1da177e4 LT	62
00d3b7a4 DH	63	/*
	64	* open an AFS file or directory and attach a key to it
	65	*/
	66	int afs_open(struct inode inode, struct file file)
	67	{
	68	struct afs_vnode *vnode = AFS_FS_I(inode);
	69	struct key *key;
260a9803	70	int ret;
00d3b7a4	71
416351f2	72	_enter("{%x:%u},", vnode->fid.vid, vnode->fid.vnode);
00d3b7a4 DH	73
	74	key = afs_request_key(vnode->volume->cell);
	75	if (IS_ERR(key)) {
	76	_leave(" = %ld [key]", PTR_ERR(key));
	77	return PTR_ERR(key);
	78	}
	79
260a9803 DH	80	ret = afs_validate(vnode, key);
	81	if (ret < 0) {
	82	_leave(" = %d [val]", ret);
	83	return ret;
	84	}
	85
00d3b7a4 DH	86	file->private_data = key;
	87	_leave(" = 0");
	88	return 0;
	89	}
	90
	91	/*
	92	* release an AFS file or directory and discard its key
	93	*/
	94	int afs_release(struct inode inode, struct file file)
	95	{
	96	struct afs_vnode *vnode = AFS_FS_I(inode);
	97
416351f2	98	_enter("{%x:%u},", vnode->fid.vid, vnode->fid.vnode);
00d3b7a4 DH	99
	100	key_put(file->private_data);
	101	_leave(" = 0");
	102	return 0;
	103	}
	104
1da177e4 LT	105	/*
	106	* deal with notification that a page was read from the cache
	107	*/
9b3f26c9 DH	108	static void afs_file_readpage_read_complete(struct page *page,
	109	void *data,
	110	int error)
1da177e4	111	{
9b3f26c9	112	_enter("%p,%p,%d", page, data, error);
1da177e4	113
9b3f26c9 DH	114	/* if the read completes with an error, we just unlock the page and let
	115	* the VM reissue the readpage */
	116	if (!error)
1da177e4 LT	117	SetPageUptodate(page);
1da177e4 LT	118	unlock_page(page);
ec26815a	119	}
1da177e4	120
1da177e4	121	/*
416351f2	122	* AFS read page from file, directory or symlink
1da177e4	123	*/
416351f2	124	static int afs_readpage(struct file file, struct page page)
1da177e4	125	{
1da177e4 LT	126	struct afs_vnode *vnode;
1da177e4 LT	127	struct inode *inode;
00d3b7a4	128	struct key *key;
08e0e7c8 DH	129	size_t len;
08e0e7c8 DH	130	off_t offset;
1da177e4 LT	131	int ret;
	132
	133	inode = page->mapping->host;
	134
00d3b7a4 DH	135	ASSERT(file != NULL);
	136	key = file->private_data;
	137	ASSERT(key != NULL);
	138
	139	_enter("{%x},{%lu},{%lu}", key_serial(key), inode->i_ino, page->index);
1da177e4 LT	140
	141	vnode = AFS_FS_I(inode);
	142
cd7619d6	143	BUG_ON(!PageLocked(page));
1da177e4 LT	144
1da177e4 LT	145	ret = -ESTALE;
08e0e7c8	146	if (test_bit(AFS_VNODE_DELETED, &vnode->flags))
1da177e4 LT	147	goto error;
1da177e4 LT	148
1da177e4	149	/* is it cached? */
9b3f26c9 DH	150	#ifdef CONFIG_AFS_FSCACHE
9b3f26c9 DH	151	ret = fscache_read_or_alloc_page(vnode->cache,
1da177e4 LT	152	page,
	153	afs_file_readpage_read_complete,
	154	NULL,
	155	GFP_KERNEL);
	156	#else
	157	ret = -ENOBUFS;
	158	#endif
1da177e4	159	switch (ret) {
1da177e4 LT	160	/* read BIO submitted (page in cache) */
	161	case 0:
	162	break;
	163
9b3f26c9	164	/* page not yet cached */
1da177e4	165	case -ENODATA:
9b3f26c9 DH	166	_debug("cache said ENODATA");
	167	goto go_on;
	168
	169	/* page will not be cached */
	170	case -ENOBUFS:
	171	_debug("cache said ENOBUFS");
1da177e4	172	default:
9b3f26c9	173	go_on:
08e0e7c8 DH	174	offset = page->index << PAGE_CACHE_SHIFT;
08e0e7c8 DH	175	len = min_t(size_t, i_size_read(inode) - offset, PAGE_SIZE);
1da177e4 LT	176
	177	/* read the contents of the file from the server into the
	178	* page */
00d3b7a4	179	ret = afs_vnode_fetch_data(vnode, key, offset, len, page);
1da177e4	180	if (ret < 0) {
08e0e7c8	181	if (ret == -ENOENT) {
1da177e4 LT	182	_debug("got NOENT from server"
1da177e4 LT	183	" - marking file deleted and stale");
08e0e7c8	184	set_bit(AFS_VNODE_DELETED, &vnode->flags);
1da177e4 LT	185	ret = -ESTALE;
1da177e4 LT	186	}
9b3f26c9 DH	187
	188	#ifdef CONFIG_AFS_FSCACHE
	189	fscache_uncache_page(vnode->cache, page);
1da177e4	190	#endif
9b3f26c9	191	BUG_ON(PageFsCache(page));
1da177e4 LT	192	goto error;
	193	}
	194
	195	SetPageUptodate(page);
	196
9b3f26c9 DH	197	/* send the page to the cache */
	198	#ifdef CONFIG_AFS_FSCACHE
	199	if (PageFsCache(page) &&
	200	fscache_write_page(vnode->cache, page, GFP_KERNEL) != 0) {
	201	fscache_uncache_page(vnode->cache, page);
	202	BUG_ON(PageFsCache(page));
1da177e4	203	}
1da177e4	204	#endif
9b3f26c9	205	unlock_page(page);
1da177e4 LT	206	}
	207
	208	_leave(" = 0");
	209	return 0;
	210
08e0e7c8	211	error:
1da177e4 LT	212	SetPageError(page);
1da177e4 LT	213	unlock_page(page);
1da177e4 LT	214	_leave(" = %d", ret);
1da177e4 LT	215	return ret;
ec26815a	216	}
1da177e4	217
1da177e4	218	/*
9b3f26c9	219	* read a set of pages
1da177e4	220	*/
9b3f26c9 DH	221	static int afs_readpages(struct file file, struct address_space mapping,
9b3f26c9 DH	222	struct list_head *pages, unsigned nr_pages)
1da177e4	223	{
9b3f26c9 DH	224	struct afs_vnode *vnode;
9b3f26c9 DH	225	int ret = 0;
1da177e4	226
9b3f26c9	227	_enter(",{%lu},,%d", mapping->host->i_ino, nr_pages);
1da177e4	228
9b3f26c9 DH	229	vnode = AFS_FS_I(mapping->host);
	230	if (vnode->flags & AFS_VNODE_DELETED) {
	231	_leave(" = -ESTALE");
	232	return -ESTALE;
	233	}
1da177e4	234
9b3f26c9 DH	235	/* attempt to read as many of the pages as possible */
	236	#ifdef CONFIG_AFS_FSCACHE
	237	ret = fscache_read_or_alloc_pages(vnode->cache,
	238	mapping,
	239	pages,
	240	&nr_pages,
	241	afs_file_readpage_read_complete,
	242	NULL,
	243	mapping_gfp_mask(mapping));
	244	#else
	245	ret = -ENOBUFS;
	246	#endif
	247
	248	switch (ret) {
	249	/* all pages are being read from the cache */
	250	case 0:
	251	BUG_ON(!list_empty(pages));
	252	BUG_ON(nr_pages != 0);
	253	_leave(" = 0 [reading all]");
	254	return 0;
	255
	256	/* there were pages that couldn't be read from the cache */
	257	case -ENODATA:
	258	case -ENOBUFS:
	259	break;
	260
	261	/* other error */
	262	default:
	263	_leave(" = %d", ret);
	264	return ret;
1da177e4 LT	265	}
1da177e4 LT	266
9b3f26c9 DH	267	/* load the missing pages from the network */
	268	ret = read_cache_pages(mapping, pages, (void *) afs_readpage, file);
	269
	270	_leave(" = %d [netting]", ret);
	271	return ret;
ec26815a	272	}
1da177e4	273
31143d5d DH	274	/*
	275	* write back a dirty page
	276	*/
	277	static int afs_launder_page(struct page *page)
	278	{
	279	_enter("{%lu}", page->index);
	280
	281	return 0;
	282	}
	283
1da177e4	284	/*
9b3f26c9 DH	285	* invalidate part or all of a page
	286	* - release a page and clean up its private data if offset is 0 (indicating
	287	* the entire page)
	288	*/
	289	static void afs_invalidatepage(struct page *page, unsigned long offset)
	290	{
	291	struct afs_writeback wb = (struct afs_writeback ) page_private(page);
	292
	293	_enter("{%lu},%lu", page->index, offset);
	294
	295	BUG_ON(!PageLocked(page));
	296
	297	/* we clean up only if the entire page is being invalidated */
	298	if (offset == 0) {
	299	#ifdef CONFIG_AFS_FSCACHE
	300	if (PageFsCache(page)) {
	301	struct afs_vnode *vnode = AFS_FS_I(page->mapping->host);
	302	fscache_wait_on_page_write(vnode->cache, page);
	303	fscache_uncache_page(vnode->cache, page);
	304	ClearPageFsCache(page);
	305	}
	306	#endif
	307
	308	if (PagePrivate(page)) {
	309	if (wb && !PageWriteback(page)) {
	310	set_page_private(page, 0);
	311	afs_put_writeback(wb);
	312	}
	313
	314	if (!page_private(page))
	315	ClearPagePrivate(page);
	316	}
	317	}
	318
	319	_leave("");
	320	}
	321
	322	/*
	323	* release a page and clean up its private state if it's not busy
	324	* - return true if the page can now be released, false if not
1da177e4	325	*/
416351f2	326	static int afs_releasepage(struct page *page, gfp_t gfp_flags)
1da177e4	327	{
9b3f26c9	328	struct afs_writeback wb = (struct afs_writeback ) page_private(page);
416351f2	329	struct afs_vnode *vnode = AFS_FS_I(page->mapping->host);
1da177e4	330
416351f2 DH	331	_enter("{{%x:%u}[%lu],%lx},%x",
	332	vnode->fid.vid, vnode->fid.vnode, page->index, page->flags,
	333	gfp_flags);
1da177e4	334
9b3f26c9 DH	335	/* deny if page is being written to the cache and the caller hasn't
	336	* elected to wait */
	337	#ifdef CONFIG_AFS_FSCACHE
	338	if (PageFsCache(page)) {
	339	if (fscache_check_page_write(vnode->cache, page)) {
	340	if (!(gfp_flags & __GFP_WAIT)) {
	341	_leave(" = F [cache busy]");
	342	return 0;
	343	}
	344	fscache_wait_on_page_write(vnode->cache, page);
	345	}
	346
	347	fscache_uncache_page(vnode->cache, page);
	348	ClearPageFsCache(page);
	349	}
	350	#endif
	351
1da177e4	352	if (PagePrivate(page)) {
9b3f26c9 DH	353	if (wb) {
	354	set_page_private(page, 0);
	355	afs_put_writeback(wb);
	356	}
1da177e4	357	ClearPagePrivate(page);
1da177e4 LT	358	}
1da177e4 LT	359
9b3f26c9 DH	360	/* indicate that the page can be released */
	361	_leave(" = T");
	362	return 1;
ec26815a	363	}