linux/fs/nfs/fscache.h
David Howells d7bdba1c81 9p, afs, ceph, nfs: Use current_is_kswapd() rather than gfpflags_allow_blocking()
In 9p, afs ceph, and nfs, gfpflags_allow_blocking() (which wraps a
test for __GFP_DIRECT_RECLAIM being set) is used to determine if
->releasepage() should wait for the completion of a DIO write to fscache
with something like:

	if (folio_test_fscache(folio)) {
		if (!gfpflags_allow_blocking(gfp) || !(gfp & __GFP_FS))
			return false;
		folio_wait_fscache(folio);
	}

Instead, current_is_kswapd() should be used instead.

Note that this is based on a patch originally by Zhaoyang Huang[1].  In
addition to extending it to the other network filesystems and putting it on
top of my fscache rewrite, it also needs to include linux/swap.h in a bunch
of places.  Can current_is_kswapd() be moved to linux/mm.h?

Changes
=======
ver #5:
 - Dropping the changes for cifs.

Originally-signed-off-by: Zhaoyang Huang <zhaoyang.huang@unisoc.com>
Co-developed-by: David Howells <dhowells@redhat.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: Zhaoyang Huang <zhaoyang.huang@unisoc.com>
cc: Dominique Martinet <asmadeus@codewreck.org>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: Steve French <smfrench@gmail.com>
cc: Trond Myklebust <trond.myklebust@hammerspace.com>
cc: linux-cachefs@redhat.com
cc: v9fs-developer@lists.sourceforge.net
cc: linux-afs@lists.infradead.org
cc: ceph-devel@vger.kernel.org
cc: linux-cifs@vger.kernel.org
cc: linux-nfs@vger.kernel.org
cc: linux-mm@kvack.org
Link: https://lore.kernel.org/r/1638952658-20285-1-git-send-email-huangzhaoyang@gmail.com/ [1]
Link: https://lore.kernel.org/r/164021590773.640689.16777975200823659231.stgit@warthog.procyon.org.uk/ # v4
2022-01-11 22:27:42 +00:00

157 lines
4.5 KiB
C

/* SPDX-License-Identifier: GPL-2.0-or-later */
/* NFS filesystem cache interface definitions
*
* Copyright (C) 2008 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*/
#ifndef _NFS_FSCACHE_H
#define _NFS_FSCACHE_H
#include <linux/swap.h>
#include <linux/nfs_fs.h>
#include <linux/nfs_mount.h>
#include <linux/nfs4_mount.h>
#include <linux/fscache.h>
#include <linux/iversion.h>
#ifdef CONFIG_NFS_FSCACHE
/*
* Definition of the auxiliary data attached to NFS inode storage objects
* within the cache.
*
* The contents of this struct are recorded in the on-disk local cache in the
* auxiliary data attached to the data storage object backing an inode. This
* permits coherency to be managed when a new inode binds to an already extant
* cache object.
*/
struct nfs_fscache_inode_auxdata {
s64 mtime_sec;
s64 mtime_nsec;
s64 ctime_sec;
s64 ctime_nsec;
u64 change_attr;
};
/*
* fscache.c
*/
extern int nfs_fscache_get_super_cookie(struct super_block *, const char *, int);
extern void nfs_fscache_release_super_cookie(struct super_block *);
extern void nfs_fscache_init_inode(struct inode *);
extern void nfs_fscache_clear_inode(struct inode *);
extern void nfs_fscache_open_file(struct inode *, struct file *);
extern void nfs_fscache_release_file(struct inode *, struct file *);
extern int __nfs_readpage_from_fscache(struct inode *, struct page *);
extern void __nfs_read_completion_to_fscache(struct nfs_pgio_header *hdr,
unsigned long bytes);
extern void __nfs_readpage_to_fscache(struct inode *, struct page *);
static inline int nfs_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(nfs_i_fscache(page->mapping->host));
nfs_inc_fscache_stats(page->mapping->host,
NFSIOS_FSCACHE_PAGES_UNCACHED);
}
return true;
}
/*
* Retrieve a page from an inode data storage object.
*/
static inline int nfs_readpage_from_fscache(struct inode *inode,
struct page *page)
{
if (NFS_I(inode)->fscache)
return __nfs_readpage_from_fscache(inode, page);
return -ENOBUFS;
}
/*
* Store a page newly fetched from the server in an inode data storage object
* in the cache.
*/
static inline void nfs_readpage_to_fscache(struct inode *inode,
struct page *page)
{
if (NFS_I(inode)->fscache)
__nfs_readpage_to_fscache(inode, page);
}
static inline void nfs_fscache_update_auxdata(struct nfs_fscache_inode_auxdata *auxdata,
struct nfs_inode *nfsi)
{
memset(auxdata, 0, sizeof(*auxdata));
auxdata->mtime_sec = nfsi->vfs_inode.i_mtime.tv_sec;
auxdata->mtime_nsec = nfsi->vfs_inode.i_mtime.tv_nsec;
auxdata->ctime_sec = nfsi->vfs_inode.i_ctime.tv_sec;
auxdata->ctime_nsec = nfsi->vfs_inode.i_ctime.tv_nsec;
if (NFS_SERVER(&nfsi->vfs_inode)->nfs_client->rpc_ops->version == 4)
auxdata->change_attr = inode_peek_iversion_raw(&nfsi->vfs_inode);
}
/*
* Invalidate the contents of fscache for this inode. This will not sleep.
*/
static inline void nfs_fscache_invalidate(struct inode *inode, int flags)
{
struct nfs_fscache_inode_auxdata auxdata;
struct nfs_inode *nfsi = NFS_I(inode);
if (nfsi->fscache) {
nfs_fscache_update_auxdata(&auxdata, nfsi);
fscache_invalidate(nfsi->fscache, &auxdata,
i_size_read(&nfsi->vfs_inode), flags);
}
}
/*
* indicate the client caching state as readable text
*/
static inline const char *nfs_server_fscache_state(struct nfs_server *server)
{
if (server->fscache)
return "yes";
return "no ";
}
#else /* CONFIG_NFS_FSCACHE */
static inline void nfs_fscache_release_super_cookie(struct super_block *sb) {}
static inline void nfs_fscache_init_inode(struct inode *inode) {}
static inline void nfs_fscache_clear_inode(struct inode *inode) {}
static inline void nfs_fscache_open_file(struct inode *inode,
struct file *filp) {}
static inline void nfs_fscache_release_file(struct inode *inode, struct file *file) {}
static inline int nfs_fscache_release_page(struct page *page, gfp_t gfp)
{
return 1; /* True: may release page */
}
static inline int nfs_readpage_from_fscache(struct inode *inode,
struct page *page)
{
return -ENOBUFS;
}
static inline void nfs_readpage_to_fscache(struct inode *inode,
struct page *page) {}
static inline void nfs_fscache_invalidate(struct inode *inode, int flags) {}
static inline const char *nfs_server_fscache_state(struct nfs_server *server)
{
return "no ";
}
#endif /* CONFIG_NFS_FSCACHE */
#endif /* _NFS_FSCACHE_H */