linux-stable/fs/cifs/fscache.h
Linus Torvalds e81fb4198e netfs: Further cleanups after struct netfs_inode wrapper introduced
Change the signature of netfs helper functions to take a struct netfs_inode
pointer rather than a struct inode pointer where appropriate, thereby
relieving the need for the network filesystem to convert its internal inode
format down to the VFS inode only for netfslib to bounce it back up.  For
type safety, it's better not to do that (and it's less typing too).

Give netfs_write_begin() an extra argument to pass in a pointer to the
netfs_inode struct rather than deriving it internally from the file
pointer.  Note that the ->write_begin() and ->write_end() ops are intended
to be replaced in the future by netfslib code that manages this without the
need to call in twice for each page.

netfs_readpage() and similar are intended to be pointed at directly by the
address_space_operations table, so must stick to the signature dictated by
the function pointers there.

Changes
=======
- Updated the kerneldoc comments and documentation [DH].

Signed-off-by: David Howells <dhowells@redhat.com>
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/CAHk-=wgkwKyNmNdKpQkqZ6DnmUL-x9hp0YBnUGjaPFEAdxDTbw@mail.gmail.com/
2022-06-10 20:55:21 +01:00

164 lines
4.7 KiB
C

/* SPDX-License-Identifier: LGPL-2.1 */
/*
* CIFS filesystem cache interface definitions
*
* Copyright (c) 2010 Novell, Inc.
* Authors(s): Suresh Jayaraman (sjayaraman@suse.de>
*
*/
#ifndef _CIFS_FSCACHE_H
#define _CIFS_FSCACHE_H
#include <linux/swap.h>
#include <linux/fscache.h>
#include "cifsglob.h"
/*
* Coherency data attached to CIFS volume within the cache
*/
struct cifs_fscache_volume_coherency_data {
__le64 resource_id; /* unique server resource id */
__le64 vol_create_time;
__le32 vol_serial_number;
} __packed;
/*
* Coherency data attached to CIFS inode within the cache.
*/
struct cifs_fscache_inode_coherency_data {
__le64 last_write_time_sec;
__le64 last_change_time_sec;
__le32 last_write_time_nsec;
__le32 last_change_time_nsec;
};
#ifdef CONFIG_CIFS_FSCACHE
/*
* fscache.c
*/
extern int cifs_fscache_get_super_cookie(struct cifs_tcon *);
extern void cifs_fscache_release_super_cookie(struct cifs_tcon *);
extern void cifs_fscache_get_inode_cookie(struct inode *inode);
extern void cifs_fscache_release_inode_cookie(struct inode *);
extern void cifs_fscache_unuse_inode_cookie(struct inode *inode, bool update);
static inline
void cifs_fscache_fill_coherency(struct inode *inode,
struct cifs_fscache_inode_coherency_data *cd)
{
struct cifsInodeInfo *cifsi = CIFS_I(inode);
memset(cd, 0, sizeof(*cd));
cd->last_write_time_sec = cpu_to_le64(cifsi->netfs.inode.i_mtime.tv_sec);
cd->last_write_time_nsec = cpu_to_le32(cifsi->netfs.inode.i_mtime.tv_nsec);
cd->last_change_time_sec = cpu_to_le64(cifsi->netfs.inode.i_ctime.tv_sec);
cd->last_change_time_nsec = cpu_to_le32(cifsi->netfs.inode.i_ctime.tv_nsec);
}
static inline struct fscache_cookie *cifs_inode_cookie(struct inode *inode)
{
return netfs_i_cookie(&CIFS_I(inode)->netfs);
}
static inline void cifs_invalidate_cache(struct inode *inode, unsigned int flags)
{
struct cifs_fscache_inode_coherency_data cd;
cifs_fscache_fill_coherency(inode, &cd);
fscache_invalidate(cifs_inode_cookie(inode), &cd,
i_size_read(inode), flags);
}
extern int __cifs_fscache_query_occupancy(struct inode *inode,
pgoff_t first, unsigned int nr_pages,
pgoff_t *_data_first,
unsigned int *_data_nr_pages);
static inline int cifs_fscache_query_occupancy(struct inode *inode,
pgoff_t first, unsigned int nr_pages,
pgoff_t *_data_first,
unsigned int *_data_nr_pages)
{
if (!cifs_inode_cookie(inode))
return -ENOBUFS;
return __cifs_fscache_query_occupancy(inode, first, nr_pages,
_data_first, _data_nr_pages);
}
extern int __cifs_readpage_from_fscache(struct inode *pinode, struct page *ppage);
extern void __cifs_readpage_to_fscache(struct inode *pinode, struct page *ppage);
static inline int cifs_readpage_from_fscache(struct inode *inode,
struct page *page)
{
if (cifs_inode_cookie(inode))
return __cifs_readpage_from_fscache(inode, page);
return -ENOBUFS;
}
static inline void cifs_readpage_to_fscache(struct inode *inode,
struct page *page)
{
if (cifs_inode_cookie(inode))
__cifs_readpage_to_fscache(inode, page);
}
static inline int cifs_fscache_release_page(struct page *page, gfp_t gfp)
{
if (PageFsCache(page)) {
if (current_is_kswapd() || !(gfp & __GFP_FS))
return false;
wait_on_page_fscache(page);
fscache_note_page_release(cifs_inode_cookie(page->mapping->host));
}
return true;
}
#else /* CONFIG_CIFS_FSCACHE */
static inline
void cifs_fscache_fill_coherency(struct inode *inode,
struct cifs_fscache_inode_coherency_data *cd)
{
}
static inline int cifs_fscache_get_super_cookie(struct cifs_tcon *tcon) { return 0; }
static inline void cifs_fscache_release_super_cookie(struct cifs_tcon *tcon) {}
static inline void cifs_fscache_get_inode_cookie(struct inode *inode) {}
static inline void cifs_fscache_release_inode_cookie(struct inode *inode) {}
static inline void cifs_fscache_unuse_inode_cookie(struct inode *inode, bool update) {}
static inline struct fscache_cookie *cifs_inode_cookie(struct inode *inode) { return NULL; }
static inline void cifs_invalidate_cache(struct inode *inode, unsigned int flags) {}
static inline int cifs_fscache_query_occupancy(struct inode *inode,
pgoff_t first, unsigned int nr_pages,
pgoff_t *_data_first,
unsigned int *_data_nr_pages)
{
*_data_first = ULONG_MAX;
*_data_nr_pages = 0;
return -ENOBUFS;
}
static inline int
cifs_readpage_from_fscache(struct inode *inode, struct page *page)
{
return -ENOBUFS;
}
static inline
void cifs_readpage_to_fscache(struct inode *inode, struct page *page) {}
static inline int nfs_fscache_release_page(struct page *page, gfp_t gfp)
{
return true; /* May release page */
}
#endif /* CONFIG_CIFS_FSCACHE */
#endif /* _CIFS_FSCACHE_H */