mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-12-13 03:16:49 +07:00
090d2b185d
Add read_mapping_page() which is used for callers that pass mapping->a_ops->readpage as the filler for read_cache_page. This removes some duplication from filesystem code. Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
109 lines
4.0 KiB
C
109 lines
4.0 KiB
C
/**
|
|
* aops.h - Defines for NTFS kernel address space operations and page cache
|
|
* handling. Part of the Linux-NTFS project.
|
|
*
|
|
* Copyright (c) 2001-2004 Anton Altaparmakov
|
|
* Copyright (c) 2002 Richard Russon
|
|
*
|
|
* This program/include file 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.
|
|
*
|
|
* This program/include file 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 (in the main directory of the Linux-NTFS
|
|
* distribution in the file COPYING); if not, write to the Free Software
|
|
* Foundation,Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
|
|
*/
|
|
|
|
#ifndef _LINUX_NTFS_AOPS_H
|
|
#define _LINUX_NTFS_AOPS_H
|
|
|
|
#include <linux/mm.h>
|
|
#include <linux/highmem.h>
|
|
#include <linux/pagemap.h>
|
|
#include <linux/fs.h>
|
|
|
|
#include "inode.h"
|
|
|
|
/**
|
|
* ntfs_unmap_page - release a page that was mapped using ntfs_map_page()
|
|
* @page: the page to release
|
|
*
|
|
* Unpin, unmap and release a page that was obtained from ntfs_map_page().
|
|
*/
|
|
static inline void ntfs_unmap_page(struct page *page)
|
|
{
|
|
kunmap(page);
|
|
page_cache_release(page);
|
|
}
|
|
|
|
/**
|
|
* ntfs_map_page - map a page into accessible memory, reading it if necessary
|
|
* @mapping: address space for which to obtain the page
|
|
* @index: index into the page cache for @mapping of the page to map
|
|
*
|
|
* Read a page from the page cache of the address space @mapping at position
|
|
* @index, where @index is in units of PAGE_CACHE_SIZE, and not in bytes.
|
|
*
|
|
* If the page is not in memory it is loaded from disk first using the readpage
|
|
* method defined in the address space operations of @mapping and the page is
|
|
* added to the page cache of @mapping in the process.
|
|
*
|
|
* If the page belongs to an mst protected attribute and it is marked as such
|
|
* in its ntfs inode (NInoMstProtected()) the mst fixups are applied but no
|
|
* error checking is performed. This means the caller has to verify whether
|
|
* the ntfs record(s) contained in the page are valid or not using one of the
|
|
* ntfs_is_XXXX_record{,p}() macros, where XXXX is the record type you are
|
|
* expecting to see. (For details of the macros, see fs/ntfs/layout.h.)
|
|
*
|
|
* If the page is in high memory it is mapped into memory directly addressible
|
|
* by the kernel.
|
|
*
|
|
* Finally the page count is incremented, thus pinning the page into place.
|
|
*
|
|
* The above means that page_address(page) can be used on all pages obtained
|
|
* with ntfs_map_page() to get the kernel virtual address of the page.
|
|
*
|
|
* When finished with the page, the caller has to call ntfs_unmap_page() to
|
|
* unpin, unmap and release the page.
|
|
*
|
|
* Note this does not grant exclusive access. If such is desired, the caller
|
|
* must provide it independently of the ntfs_{un}map_page() calls by using
|
|
* a {rw_}semaphore or other means of serialization. A spin lock cannot be
|
|
* used as ntfs_map_page() can block.
|
|
*
|
|
* The unlocked and uptodate page is returned on success or an encoded error
|
|
* on failure. Caller has to test for error using the IS_ERR() macro on the
|
|
* return value. If that evaluates to TRUE, the negative error code can be
|
|
* obtained using PTR_ERR() on the return value of ntfs_map_page().
|
|
*/
|
|
static inline struct page *ntfs_map_page(struct address_space *mapping,
|
|
unsigned long index)
|
|
{
|
|
struct page *page = read_mapping_page(mapping, index, NULL);
|
|
|
|
if (!IS_ERR(page)) {
|
|
wait_on_page_locked(page);
|
|
kmap(page);
|
|
if (PageUptodate(page) && !PageError(page))
|
|
return page;
|
|
ntfs_unmap_page(page);
|
|
return ERR_PTR(-EIO);
|
|
}
|
|
return page;
|
|
}
|
|
|
|
#ifdef NTFS_RW
|
|
|
|
extern void mark_ntfs_record_dirty(struct page *page, const unsigned int ofs);
|
|
|
|
#endif /* NTFS_RW */
|
|
|
|
#endif /* _LINUX_NTFS_AOPS_H */
|