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1/**
2 * aops.h - Defines for NTFS kernel address space operations and page cache
3 * handling. Part of the Linux-NTFS project.
4 *
5 * Copyright (c) 2001-2004 Anton Altaparmakov
6 * Copyright (c) 2002 Richard Russon
7 *
8 * This program/include file is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License as published
10 * by the Free Software Foundation; either version 2 of the License, or
11 * (at your option) any later version.
12 *
13 * This program/include file is distributed in the hope that it will be
14 * useful, but WITHOUT ANY WARRANTY; without even the implied warranty
15 * of 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 (in the main directory of the Linux-NTFS
20 * distribution in the file COPYING); if not, write to the Free Software
21 * Foundation,Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
22 */
23
24#ifndef _LINUX_NTFS_AOPS_H
25#define _LINUX_NTFS_AOPS_H
26
27#include <linux/mm.h>
28#include <linux/highmem.h>
29#include <linux/pagemap.h>
30#include <linux/fs.h>
31
32#include "inode.h"
33
34/**
35 * ntfs_unmap_page - release a page that was mapped using ntfs_map_page()
36 * @page: the page to release
37 *
38 * Unpin, unmap and release a page that was obtained from ntfs_map_page().
39 */
40static inline void ntfs_unmap_page(struct page *page)
41{
42 kunmap(page);
43 page_cache_release(page);
44}
45
46/**
47 * ntfs_map_page - map a page into accessible memory, reading it if necessary
48 * @mapping: address space for which to obtain the page
49 * @index: index into the page cache for @mapping of the page to map
50 *
51 * Read a page from the page cache of the address space @mapping at position
52 * @index, where @index is in units of PAGE_CACHE_SIZE, and not in bytes.
53 *
54 * If the page is not in memory it is loaded from disk first using the readpage
55 * method defined in the address space operations of @mapping and the page is
56 * added to the page cache of @mapping in the process.
57 *
58 * If the page belongs to an mst protected attribute and it is marked as such
59 * in its ntfs inode (NInoMstProtected()) the mst fixups are applied but no
60 * error checking is performed. This means the caller has to verify whether
61 * the ntfs record(s) contained in the page are valid or not using one of the
62 * ntfs_is_XXXX_record{,p}() macros, where XXXX is the record type you are
63 * expecting to see. (For details of the macros, see fs/ntfs/layout.h.)
64 *
65 * If the page is in high memory it is mapped into memory directly addressible
66 * by the kernel.
67 *
68 * Finally the page count is incremented, thus pinning the page into place.
69 *
70 * The above means that page_address(page) can be used on all pages obtained
71 * with ntfs_map_page() to get the kernel virtual address of the page.
72 *
73 * When finished with the page, the caller has to call ntfs_unmap_page() to
74 * unpin, unmap and release the page.
75 *
76 * Note this does not grant exclusive access. If such is desired, the caller
77 * must provide it independently of the ntfs_{un}map_page() calls by using
78 * a {rw_}semaphore or other means of serialization. A spin lock cannot be
79 * used as ntfs_map_page() can block.
80 *
81 * The unlocked and uptodate page is returned on success or an encoded error
82 * on failure. Caller has to test for error using the IS_ERR() macro on the
83 * return value. If that evaluates to 'true', the negative error code can be
84 * obtained using PTR_ERR() on the return value of ntfs_map_page().
85 */
86static inline struct page *ntfs_map_page(struct address_space *mapping,
87 unsigned long index)
88{
89 struct page *page = read_mapping_page(mapping, index, NULL);
90
91 if (!IS_ERR(page)) {
92 kmap(page);
93 if (!PageError(page))
94 return page;
95 ntfs_unmap_page(page);
96 return ERR_PTR(-EIO);
97 }
98 return page;
99}
100
101#ifdef NTFS_RW
102
103extern void mark_ntfs_record_dirty(struct page *page, const unsigned int ofs);
104
105#endif /* NTFS_RW */
106
107#endif /* _LINUX_NTFS_AOPS_H */
1/* SPDX-License-Identifier: GPL-2.0-or-later */
2/**
3 * aops.h - Defines for NTFS kernel address space operations and page cache
4 * handling. Part of the Linux-NTFS project.
5 *
6 * Copyright (c) 2001-2004 Anton Altaparmakov
7 * Copyright (c) 2002 Richard Russon
8 */
9
10#ifndef _LINUX_NTFS_AOPS_H
11#define _LINUX_NTFS_AOPS_H
12
13#include <linux/mm.h>
14#include <linux/highmem.h>
15#include <linux/pagemap.h>
16#include <linux/fs.h>
17
18#include "inode.h"
19
20/**
21 * ntfs_unmap_page - release a page that was mapped using ntfs_map_page()
22 * @page: the page to release
23 *
24 * Unpin, unmap and release a page that was obtained from ntfs_map_page().
25 */
26static inline void ntfs_unmap_page(struct page *page)
27{
28 kunmap(page);
29 put_page(page);
30}
31
32/**
33 * ntfs_map_page - map a page into accessible memory, reading it if necessary
34 * @mapping: address space for which to obtain the page
35 * @index: index into the page cache for @mapping of the page to map
36 *
37 * Read a page from the page cache of the address space @mapping at position
38 * @index, where @index is in units of PAGE_SIZE, and not in bytes.
39 *
40 * If the page is not in memory it is loaded from disk first using the readpage
41 * method defined in the address space operations of @mapping and the page is
42 * added to the page cache of @mapping in the process.
43 *
44 * If the page belongs to an mst protected attribute and it is marked as such
45 * in its ntfs inode (NInoMstProtected()) the mst fixups are applied but no
46 * error checking is performed. This means the caller has to verify whether
47 * the ntfs record(s) contained in the page are valid or not using one of the
48 * ntfs_is_XXXX_record{,p}() macros, where XXXX is the record type you are
49 * expecting to see. (For details of the macros, see fs/ntfs/layout.h.)
50 *
51 * If the page is in high memory it is mapped into memory directly addressible
52 * by the kernel.
53 *
54 * Finally the page count is incremented, thus pinning the page into place.
55 *
56 * The above means that page_address(page) can be used on all pages obtained
57 * with ntfs_map_page() to get the kernel virtual address of the page.
58 *
59 * When finished with the page, the caller has to call ntfs_unmap_page() to
60 * unpin, unmap and release the page.
61 *
62 * Note this does not grant exclusive access. If such is desired, the caller
63 * must provide it independently of the ntfs_{un}map_page() calls by using
64 * a {rw_}semaphore or other means of serialization. A spin lock cannot be
65 * used as ntfs_map_page() can block.
66 *
67 * The unlocked and uptodate page is returned on success or an encoded error
68 * on failure. Caller has to test for error using the IS_ERR() macro on the
69 * return value. If that evaluates to 'true', the negative error code can be
70 * obtained using PTR_ERR() on the return value of ntfs_map_page().
71 */
72static inline struct page *ntfs_map_page(struct address_space *mapping,
73 unsigned long index)
74{
75 struct page *page = read_mapping_page(mapping, index, NULL);
76
77 if (!IS_ERR(page)) {
78 kmap(page);
79 if (!PageError(page))
80 return page;
81 ntfs_unmap_page(page);
82 return ERR_PTR(-EIO);
83 }
84 return page;
85}
86
87#ifdef NTFS_RW
88
89extern void mark_ntfs_record_dirty(struct page *page, const unsigned int ofs);
90
91#endif /* NTFS_RW */
92
93#endif /* _LINUX_NTFS_AOPS_H */