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Based on 1 normalized pattern(s): 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 extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 43 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Richard Fontana <rfontana@redhat.com> Reviewed-by: Allison Randal <allison@lohutok.net> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190520075212.517001706@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
94 lines
3.2 KiB
C
94 lines
3.2 KiB
C
/* SPDX-License-Identifier: GPL-2.0-or-later */
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/**
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* aops.h - Defines for NTFS kernel address space operations and page cache
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* handling. Part of the Linux-NTFS project.
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*
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* Copyright (c) 2001-2004 Anton Altaparmakov
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* Copyright (c) 2002 Richard Russon
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*/
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#ifndef _LINUX_NTFS_AOPS_H
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#define _LINUX_NTFS_AOPS_H
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#include <linux/mm.h>
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#include <linux/highmem.h>
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#include <linux/pagemap.h>
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#include <linux/fs.h>
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#include "inode.h"
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/**
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* ntfs_unmap_page - release a page that was mapped using ntfs_map_page()
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* @page: the page to release
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*
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* Unpin, unmap and release a page that was obtained from ntfs_map_page().
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*/
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static inline void ntfs_unmap_page(struct page *page)
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{
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kunmap(page);
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put_page(page);
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}
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/**
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* ntfs_map_page - map a page into accessible memory, reading it if necessary
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* @mapping: address space for which to obtain the page
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* @index: index into the page cache for @mapping of the page to map
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*
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* Read a page from the page cache of the address space @mapping at position
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* @index, where @index is in units of PAGE_SIZE, and not in bytes.
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*
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* If the page is not in memory it is loaded from disk first using the readpage
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* method defined in the address space operations of @mapping and the page is
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* added to the page cache of @mapping in the process.
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*
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* If the page belongs to an mst protected attribute and it is marked as such
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* in its ntfs inode (NInoMstProtected()) the mst fixups are applied but no
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* error checking is performed. This means the caller has to verify whether
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* the ntfs record(s) contained in the page are valid or not using one of the
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* ntfs_is_XXXX_record{,p}() macros, where XXXX is the record type you are
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* expecting to see. (For details of the macros, see fs/ntfs/layout.h.)
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*
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* If the page is in high memory it is mapped into memory directly addressible
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* by the kernel.
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*
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* Finally the page count is incremented, thus pinning the page into place.
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*
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* The above means that page_address(page) can be used on all pages obtained
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* with ntfs_map_page() to get the kernel virtual address of the page.
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*
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* When finished with the page, the caller has to call ntfs_unmap_page() to
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* unpin, unmap and release the page.
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*
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* Note this does not grant exclusive access. If such is desired, the caller
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* must provide it independently of the ntfs_{un}map_page() calls by using
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* a {rw_}semaphore or other means of serialization. A spin lock cannot be
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* used as ntfs_map_page() can block.
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*
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* The unlocked and uptodate page is returned on success or an encoded error
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* on failure. Caller has to test for error using the IS_ERR() macro on the
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* return value. If that evaluates to 'true', the negative error code can be
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* obtained using PTR_ERR() on the return value of ntfs_map_page().
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*/
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static inline struct page *ntfs_map_page(struct address_space *mapping,
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unsigned long index)
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{
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struct page *page = read_mapping_page(mapping, index, NULL);
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if (!IS_ERR(page)) {
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kmap(page);
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if (!PageError(page))
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return page;
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ntfs_unmap_page(page);
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return ERR_PTR(-EIO);
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}
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return page;
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}
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#ifdef NTFS_RW
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extern void mark_ntfs_record_dirty(struct page *page, const unsigned int ofs);
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#endif /* NTFS_RW */
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#endif /* _LINUX_NTFS_AOPS_H */
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