linux/fs/cifs/fscache.h
David Howells bc899ee1c8 netfs: Add a netfs inode context
Add a netfs_i_context struct that should be included in the network
filesystem's own inode struct wrapper, directly after the VFS's inode
struct, e.g.:

	struct my_inode {
		struct {
			/* These must be contiguous */
			struct inode		vfs_inode;
			struct netfs_i_context	netfs_ctx;
		};
	};

The netfs_i_context struct so far contains a single field for the network
filesystem to use - the cache cookie:

	struct netfs_i_context {
		...
		struct fscache_cookie	*cache;
	};

Three functions are provided to help with this:

 (1) void netfs_i_context_init(struct inode *inode,
			       const struct netfs_request_ops *ops);

     Initialise the netfs context and set the operations.

 (2) struct netfs_i_context *netfs_i_context(struct inode *inode);

     Find the netfs context from the VFS inode.

 (3) struct inode *netfs_inode(struct netfs_i_context *ctx);

     Find the VFS inode from the netfs context.

Changes
=======
ver #4)
 - Fix netfs_is_cache_enabled() to check cookie->cache_priv to see if a
   cache is present[3].
 - Fix netfs_skip_folio_read() to zero out all of the page, not just some
   of it[3].

ver #3)
 - Split out the bit to move ceph cap-getting on readahead into
   ceph_init_request()[1].
 - Stick in a comment to the netfs inode structs indicating the contiguity
   requirements[2].

ver #2)
 - Adjust documentation to match.
 - Use "#if IS_ENABLED()" in netfs_i_cookie(), not "#ifdef".
 - Move the cap check from ceph_readahead() to ceph_init_request() to be
   called from netfslib.
 - Remove ceph_readahead() and use  netfs_readahead() directly instead.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Jeff Layton <jlayton@kernel.org>
cc: linux-cachefs@redhat.com

Link: https://lore.kernel.org/r/8af0d47f17d89c06bbf602496dd845f2b0bf25b3.camel@kernel.org/ [1]
Link: https://lore.kernel.org/r/beaf4f6a6c2575ed489adb14b257253c868f9a5c.camel@kernel.org/ [2]
Link: https://lore.kernel.org/r/3536452.1647421585@warthog.procyon.org.uk/ [3]
Link: https://lore.kernel.org/r/164622984545.3564931.15691742939278418580.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/164678213320.1200972.16807551936267647470.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/164692909854.2099075.9535537286264248057.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/306388.1647595110@warthog.procyon.org.uk/ # v4
2022-03-18 09:29:05 +00:00

165 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->vfs_inode.i_mtime.tv_sec);
cd->last_write_time_nsec = cpu_to_le32(cifsi->vfs_inode.i_mtime.tv_nsec);
cd->last_change_time_sec = cpu_to_le64(cifsi->vfs_inode.i_ctime.tv_sec);
cd->last_change_time_nsec = cpu_to_le32(cifsi->vfs_inode.i_ctime.tv_nsec);
}
static inline struct fscache_cookie *cifs_inode_cookie(struct inode *inode)
{
return netfs_i_cookie(inode);
}
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 */