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Diffstat (limited to 'fs/ntfs/index.h')
| -rw-r--r-- | fs/ntfs/index.h | 134 |
1 files changed, 134 insertions, 0 deletions
diff --git a/fs/ntfs/index.h b/fs/ntfs/index.h new file mode 100644 index 000000000..bb3c3ae55 --- /dev/null +++ b/fs/ntfs/index.h @@ -0,0 +1,134 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* + * index.h - Defines for NTFS kernel index handling. Part of the Linux-NTFS + * project. + * + * Copyright (c) 2004 Anton Altaparmakov + */ + +#ifndef _LINUX_NTFS_INDEX_H +#define _LINUX_NTFS_INDEX_H + +#include <linux/fs.h> + +#include "types.h" +#include "layout.h" +#include "inode.h" +#include "attrib.h" +#include "mft.h" +#include "aops.h" + +/** + * @idx_ni: index inode containing the @entry described by this context + * @entry: index entry (points into @ir or @ia) + * @data: index entry data (points into @entry) + * @data_len: length in bytes of @data + * @is_in_root: 'true' if @entry is in @ir and 'false' if it is in @ia + * @ir: index root if @is_in_root and NULL otherwise + * @actx: attribute search context if @is_in_root and NULL otherwise + * @base_ni: base inode if @is_in_root and NULL otherwise + * @ia: index block if @is_in_root is 'false' and NULL otherwise + * @page: page if @is_in_root is 'false' and NULL otherwise + * + * @idx_ni is the index inode this context belongs to. + * + * @entry is the index entry described by this context. @data and @data_len + * are the index entry data and its length in bytes, respectively. @data + * simply points into @entry. This is probably what the user is interested in. + * + * If @is_in_root is 'true', @entry is in the index root attribute @ir described + * by the attribute search context @actx and the base inode @base_ni. @ia and + * @page are NULL in this case. + * + * If @is_in_root is 'false', @entry is in the index allocation attribute and @ia + * and @page point to the index allocation block and the mapped, locked page it + * is in, respectively. @ir, @actx and @base_ni are NULL in this case. + * + * To obtain a context call ntfs_index_ctx_get(). + * + * We use this context to allow ntfs_index_lookup() to return the found index + * @entry and its @data without having to allocate a buffer and copy the @entry + * and/or its @data into it. + * + * When finished with the @entry and its @data, call ntfs_index_ctx_put() to + * free the context and other associated resources. + * + * If the index entry was modified, call flush_dcache_index_entry_page() + * immediately after the modification and either ntfs_index_entry_mark_dirty() + * or ntfs_index_entry_write() before the call to ntfs_index_ctx_put() to + * ensure that the changes are written to disk. + */ +typedef struct { + ntfs_inode *idx_ni; + INDEX_ENTRY *entry; + void *data; + u16 data_len; + bool is_in_root; + INDEX_ROOT *ir; + ntfs_attr_search_ctx *actx; + ntfs_inode *base_ni; + INDEX_ALLOCATION *ia; + struct page *page; +} ntfs_index_context; + +extern ntfs_index_context *ntfs_index_ctx_get(ntfs_inode *idx_ni); +extern void ntfs_index_ctx_put(ntfs_index_context *ictx); + +extern int ntfs_index_lookup(const void *key, const int key_len, + ntfs_index_context *ictx); + +#ifdef NTFS_RW + +/** + * ntfs_index_entry_flush_dcache_page - flush_dcache_page() for index entries + * @ictx: ntfs index context describing the index entry + * + * Call flush_dcache_page() for the page in which an index entry resides. + * + * This must be called every time an index entry is modified, just after the + * modification. + * + * If the index entry is in the index root attribute, simply flush the page + * containing the mft record containing the index root attribute. + * + * If the index entry is in an index block belonging to the index allocation + * attribute, simply flush the page cache page containing the index block. + */ +static inline void ntfs_index_entry_flush_dcache_page(ntfs_index_context *ictx) +{ + if (ictx->is_in_root) + flush_dcache_mft_record_page(ictx->actx->ntfs_ino); + else + flush_dcache_page(ictx->page); +} + +/** + * ntfs_index_entry_mark_dirty - mark an index entry dirty + * @ictx: ntfs index context describing the index entry + * + * Mark the index entry described by the index entry context @ictx dirty. + * + * If the index entry is in the index root attribute, simply mark the mft + * record containing the index root attribute dirty. This ensures the mft + * record, and hence the index root attribute, will be written out to disk + * later. + * + * If the index entry is in an index block belonging to the index allocation + * attribute, mark the buffers belonging to the index record as well as the + * page cache page the index block is in dirty. This automatically marks the + * VFS inode of the ntfs index inode to which the index entry belongs dirty, + * too (I_DIRTY_PAGES) and this in turn ensures the page buffers, and hence the + * dirty index block, will be written out to disk later. + */ +static inline void ntfs_index_entry_mark_dirty(ntfs_index_context *ictx) +{ + if (ictx->is_in_root) + mark_mft_record_dirty(ictx->actx->ntfs_ino); + else + mark_ntfs_record_dirty(ictx->page, + (u8*)ictx->ia - (u8*)page_address(ictx->page)); +} + +#endif /* NTFS_RW */ + +#endif /* _LINUX_NTFS_INDEX_H */ |