[linux-2.6-block.git] / fs / nfs / fscache.c

// SPDX-License-Identifier: GPL-2.0-or-later
/* NFS filesystem cache interface
 *
 * Copyright (C) 2008 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (dhowells@redhat.com)
 */

#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/nfs_fs.h>
#include <linux/nfs_fs_sb.h>
#include <linux/in6.h>
#include <linux/seq_file.h>
#include <linux/slab.h>
#include <linux/iversion.h>

#include "internal.h"
#include "iostat.h"
#include "fscache.h"

#define NFSDBG_FACILITY		NFSDBG_FSCACHE

static struct rb_root nfs_fscache_keys = RB_ROOT;
static DEFINE_SPINLOCK(nfs_fscache_keys_lock);

/*
 * Layout of the key for an NFS server cache object.
 */
struct nfs_server_key {
	struct {
		uint16_t	nfsversion;		/* NFS protocol version */
		uint16_t	family;			/* address family */
		__be16		port;			/* IP port */
	} hdr;
	union {
		struct in_addr	ipv4_addr;	/* IPv4 address */
		struct in6_addr ipv6_addr;	/* IPv6 address */
	};
} __packed;

/*
 * Get the per-client index cookie for an NFS client if the appropriate mount
 * flag was set
 * - We always try and get an index cookie for the client, but get filehandle
 *   cookies on a per-superblock basis, depending on the mount flags
 */
void nfs_fscache_get_client_cookie(struct nfs_client *clp)
{
	const struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *) &clp->cl_addr;
	const struct sockaddr_in *sin = (struct sockaddr_in *) &clp->cl_addr;
	struct nfs_server_key key;
	uint16_t len = sizeof(key.hdr);

	memset(&key, 0, sizeof(key));
	key.hdr.nfsversion = clp->rpc_ops->version;
	key.hdr.family = clp->cl_addr.ss_family;

	switch (clp->cl_addr.ss_family) {
	case AF_INET:
		key.hdr.port = sin->sin_port;
		key.ipv4_addr = sin->sin_addr;
		len += sizeof(key.ipv4_addr);
		break;

	case AF_INET6:
		key.hdr.port = sin6->sin6_port;
		key.ipv6_addr = sin6->sin6_addr;
		len += sizeof(key.ipv6_addr);
		break;

	default:
		printk(KERN_WARNING "NFS: Unknown network family '%d'\n",
		       clp->cl_addr.ss_family);
		clp->fscache = NULL;
		return;
	}

	/* create a cache index for looking up filehandles */
	clp->fscache = fscache_acquire_cookie(nfs_fscache_netfs.primary_index,
					      &nfs_fscache_server_index_def,
					      &key, len,
					      NULL, 0,
					      clp, 0, true);
	dfprintk(FSCACHE, "NFS: get client cookie (0x%p/0x%p)\n",
		 clp, clp->fscache);
}

/*
 * Dispose of a per-client cookie
 */
void nfs_fscache_release_client_cookie(struct nfs_client *clp)
{
	dfprintk(FSCACHE, "NFS: releasing client cookie (0x%p/0x%p)\n",
		 clp, clp->fscache);

	fscache_relinquish_cookie(clp->fscache, NULL, false);
	clp->fscache = NULL;
}

/*
 * Get the cache cookie for an NFS superblock.  We have to handle
 * uniquification here because the cache doesn't do it for us.
 *
 * The default uniquifier is just an empty string, but it may be overridden
 * either by the 'fsc=xxx' option to mount, or by inheriting it from the parent
 * superblock across an automount point of some nature.
 */
void nfs_fscache_get_super_cookie(struct super_block *sb, const char *uniq, int ulen)
{
	struct nfs_fscache_key *key, *xkey;
	struct nfs_server *nfss = NFS_SB(sb);
	struct rb_node **p, *parent;
	int diff;

	if (!uniq) {
		uniq = "";
		ulen = 1;
	}

	key = kzalloc(sizeof(*key) + ulen, GFP_KERNEL);
	if (!key)
		return;

	key->nfs_client = nfss->nfs_client;
	key->key.super.s_flags = sb->s_flags & NFS_MS_MASK;
	key->key.nfs_server.flags = nfss->flags;
	key->key.nfs_server.rsize = nfss->rsize;
	key->key.nfs_server.wsize = nfss->wsize;
	key->key.nfs_server.acregmin = nfss->acregmin;
	key->key.nfs_server.acregmax = nfss->acregmax;
	key->key.nfs_server.acdirmin = nfss->acdirmin;
	key->key.nfs_server.acdirmax = nfss->acdirmax;
	key->key.nfs_server.fsid = nfss->fsid;
	key->key.rpc_auth.au_flavor = nfss->client->cl_auth->au_flavor;

	key->key.uniq_len = ulen;
	memcpy(key->key.uniquifier, uniq, ulen);

	spin_lock(&nfs_fscache_keys_lock);
	p = &nfs_fscache_keys.rb_node;
	parent = NULL;
	while (*p) {
		parent = *p;
		xkey = rb_entry(parent, struct nfs_fscache_key, node);

		if (key->nfs_client < xkey->nfs_client)
			goto go_left;
		if (key->nfs_client > xkey->nfs_client)
			goto go_right;

		diff = memcmp(&key->key, &xkey->key, sizeof(key->key));
		if (diff < 0)
			goto go_left;
		if (diff > 0)
			goto go_right;

		if (key->key.uniq_len == 0)
			goto non_unique;
		diff = memcmp(key->key.uniquifier,
			      xkey->key.uniquifier,
			      key->key.uniq_len);
		if (diff < 0)
			goto go_left;
		if (diff > 0)
			goto go_right;
		goto non_unique;

	go_left:
		p = &(*p)->rb_left;
		continue;
	go_right:
		p = &(*p)->rb_right;
	}

	rb_link_node(&key->node, parent, p);
	rb_insert_color(&key->node, &nfs_fscache_keys);
	spin_unlock(&nfs_fscache_keys_lock);
	nfss->fscache_key = key;

	/* create a cache index for looking up filehandles */
	nfss->fscache = fscache_acquire_cookie(nfss->nfs_client->fscache,
					       &nfs_fscache_super_index_def,
					       key, sizeof(*key) + ulen,
					       NULL, 0,
					       nfss, 0, true);
	dfprintk(FSCACHE, "NFS: get superblock cookie (0x%p/0x%p)\n",
		 nfss, nfss->fscache);
	return;

non_unique:
	spin_unlock(&nfs_fscache_keys_lock);
	kfree(key);
	nfss->fscache_key = NULL;
	nfss->fscache = NULL;
	printk(KERN_WARNING "NFS:"
	       " Cache request denied due to non-unique superblock keys\n");
}

/*
 * release a per-superblock cookie
 */
void nfs_fscache_release_super_cookie(struct super_block *sb)
{
	struct nfs_server *nfss = NFS_SB(sb);

	dfprintk(FSCACHE, "NFS: releasing superblock cookie (0x%p/0x%p)\n",
		 nfss, nfss->fscache);

	fscache_relinquish_cookie(nfss->fscache, NULL, false);
	nfss->fscache = NULL;

	if (nfss->fscache_key) {
		spin_lock(&nfs_fscache_keys_lock);
		rb_erase(&nfss->fscache_key->node, &nfs_fscache_keys);
		spin_unlock(&nfs_fscache_keys_lock);
		kfree(nfss->fscache_key);
		nfss->fscache_key = NULL;
	}
}

/*
 * Initialise the per-inode cache cookie pointer for an NFS inode.
 */
void nfs_fscache_init_inode(struct inode *inode)
{
	struct nfs_fscache_inode_auxdata auxdata;
	struct nfs_inode *nfsi = NFS_I(inode);

	nfsi->fscache = NULL;
	if (!S_ISREG(inode->i_mode))
		return;

	memset(&auxdata, 0, sizeof(auxdata));
	auxdata.mtime = timespec64_to_timespec(nfsi->vfs_inode.i_mtime);
	auxdata.ctime = timespec64_to_timespec(nfsi->vfs_inode.i_ctime);

	if (NFS_SERVER(&nfsi->vfs_inode)->nfs_client->rpc_ops->version == 4)
		auxdata.change_attr = inode_peek_iversion_raw(&nfsi->vfs_inode);

	nfsi->fscache = fscache_acquire_cookie(NFS_SB(inode->i_sb)->fscache,
					       &nfs_fscache_inode_object_def,
					       nfsi->fh.data, nfsi->fh.size,
					       &auxdata, sizeof(auxdata),
					       nfsi, nfsi->vfs_inode.i_size, false);
}

/*
 * Release a per-inode cookie.
 */
void nfs_fscache_clear_inode(struct inode *inode)
{
	struct nfs_fscache_inode_auxdata auxdata;
	struct nfs_inode *nfsi = NFS_I(inode);
	struct fscache_cookie *cookie = nfs_i_fscache(inode);

	dfprintk(FSCACHE, "NFS: clear cookie (0x%p/0x%p)\n", nfsi, cookie);

	memset(&auxdata, 0, sizeof(auxdata));
	auxdata.mtime = timespec64_to_timespec(nfsi->vfs_inode.i_mtime);
	auxdata.ctime = timespec64_to_timespec(nfsi->vfs_inode.i_ctime);
	fscache_relinquish_cookie(cookie, &auxdata, false);
	nfsi->fscache = NULL;
}

static bool nfs_fscache_can_enable(void *data)
{
	struct inode *inode = data;

	return !inode_is_open_for_write(inode);
}

/*
 * Enable or disable caching for a file that is being opened as appropriate.
 * The cookie is allocated when the inode is initialised, but is not enabled at
 * that time.  Enablement is deferred to file-open time to avoid stat() and
 * access() thrashing the cache.
 *
 * For now, with NFS, only regular files that are open read-only will be able
 * to use the cache.
 *
 * We enable the cache for an inode if we open it read-only and it isn't
 * currently open for writing.  We disable the cache if the inode is open
 * write-only.
 *
 * The caller uses the file struct to pin i_writecount on the inode before
 * calling us when a file is opened for writing, so we can make use of that.
 *
 * Note that this may be invoked multiple times in parallel by parallel
 * nfs_open() functions.
 */
void nfs_fscache_open_file(struct inode *inode, struct file *filp)
{
	struct nfs_fscache_inode_auxdata auxdata;
	struct nfs_inode *nfsi = NFS_I(inode);
	struct fscache_cookie *cookie = nfs_i_fscache(inode);

	if (!fscache_cookie_valid(cookie))
		return;

	memset(&auxdata, 0, sizeof(auxdata));
	auxdata.mtime = timespec64_to_timespec(nfsi->vfs_inode.i_mtime);
	auxdata.ctime = timespec64_to_timespec(nfsi->vfs_inode.i_ctime);

	if (inode_is_open_for_write(inode)) {
		dfprintk(FSCACHE, "NFS: nfsi 0x%p disabling cache\n", nfsi);
		clear_bit(NFS_INO_FSCACHE, &nfsi->flags);
		fscache_disable_cookie(cookie, &auxdata, true);
		fscache_uncache_all_inode_pages(cookie, inode);
	} else {
		dfprintk(FSCACHE, "NFS: nfsi 0x%p enabling cache\n", nfsi);
		fscache_enable_cookie(cookie, &auxdata, nfsi->vfs_inode.i_size,
				      nfs_fscache_can_enable, inode);
		if (fscache_cookie_enabled(cookie))
			set_bit(NFS_INO_FSCACHE, &NFS_I(inode)->flags);
	}
}
EXPORT_SYMBOL_GPL(nfs_fscache_open_file);

/*
 * Release the caching state associated with a page, if the page isn't busy
 * interacting with the cache.
 * - Returns true (can release page) or false (page busy).
 */
int nfs_fscache_release_page(struct page *page, gfp_t gfp)
{
	if (PageFsCache(page)) {
		struct fscache_cookie *cookie = nfs_i_fscache(page->mapping->host);

		BUG_ON(!cookie);
		dfprintk(FSCACHE, "NFS: fscache releasepage (0x%p/0x%p/0x%p)\n",
			 cookie, page, NFS_I(page->mapping->host));

		if (!fscache_maybe_release_page(cookie, page, gfp))
			return 0;

		nfs_inc_fscache_stats(page->mapping->host,
				      NFSIOS_FSCACHE_PAGES_UNCACHED);
	}

	return 1;
}

/*
 * Release the caching state associated with a page if undergoing complete page
 * invalidation.
 */
void __nfs_fscache_invalidate_page(struct page *page, struct inode *inode)
{
	struct fscache_cookie *cookie = nfs_i_fscache(inode);

	BUG_ON(!cookie);

	dfprintk(FSCACHE, "NFS: fscache invalidatepage (0x%p/0x%p/0x%p)\n",
		 cookie, page, NFS_I(inode));

	fscache_wait_on_page_write(cookie, page);

	BUG_ON(!PageLocked(page));
	fscache_uncache_page(cookie, page);
	nfs_inc_fscache_stats(page->mapping->host,
			      NFSIOS_FSCACHE_PAGES_UNCACHED);
}

/*
 * Handle completion of a page being read from the cache.
 * - Called in process (keventd) context.
 */
static void nfs_readpage_from_fscache_complete(struct page *page,
					       void *context,
					       int error)
{
	dfprintk(FSCACHE,
		 "NFS: readpage_from_fscache_complete (0x%p/0x%p/%d)\n",
		 page, context, error);

	/* if the read completes with an error, we just unlock the page and let
	 * the VM reissue the readpage */
	if (!error) {
		SetPageUptodate(page);
		unlock_page(page);
	} else {
		error = nfs_readpage_async(context, page->mapping->host, page);
		if (error)
			unlock_page(page);
	}
}

/*
 * Retrieve a page from fscache
 */
int __nfs_readpage_from_fscache(struct nfs_open_context *ctx,
				struct inode *inode, struct page *page)
{
	int ret;

	dfprintk(FSCACHE,
		 "NFS: readpage_from_fscache(fsc:%p/p:%p(i:%lx f:%lx)/0x%p)\n",
		 nfs_i_fscache(inode), page, page->index, page->flags, inode);

	ret = fscache_read_or_alloc_page(nfs_i_fscache(inode),
					 page,
					 nfs_readpage_from_fscache_complete,
					 ctx,
					 GFP_KERNEL);

	switch (ret) {
	case 0: /* read BIO submitted (page in fscache) */
		dfprintk(FSCACHE,
			 "NFS:    readpage_from_fscache: BIO submitted\n");
		nfs_inc_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_READ_OK);
		return ret;

	case -ENOBUFS: /* inode not in cache */
	case -ENODATA: /* page not in cache */
		nfs_inc_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_READ_FAIL);
		dfprintk(FSCACHE,
			 "NFS:    readpage_from_fscache %d\n", ret);
		return 1;

	default:
		dfprintk(FSCACHE, "NFS:    readpage_from_fscache %d\n", ret);
		nfs_inc_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_READ_FAIL);
	}
	return ret;
}

/*
 * Retrieve a set of pages from fscache
 */
int __nfs_readpages_from_fscache(struct nfs_open_context *ctx,
				 struct inode *inode,
				 struct address_space *mapping,
				 struct list_head *pages,
				 unsigned *nr_pages)
{
	unsigned npages = *nr_pages;
	int ret;

	dfprintk(FSCACHE, "NFS: nfs_getpages_from_fscache (0x%p/%u/0x%p)\n",
		 nfs_i_fscache(inode), npages, inode);

	ret = fscache_read_or_alloc_pages(nfs_i_fscache(inode),
					  mapping, pages, nr_pages,
					  nfs_readpage_from_fscache_complete,
					  ctx,
					  mapping_gfp_mask(mapping));
	if (*nr_pages < npages)
		nfs_add_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_READ_OK,
				      npages);
	if (*nr_pages > 0)
		nfs_add_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_READ_FAIL,
				      *nr_pages);

	switch (ret) {
	case 0: /* read submitted to the cache for all pages */
		BUG_ON(!list_empty(pages));
		BUG_ON(*nr_pages != 0);
		dfprintk(FSCACHE,
			 "NFS: nfs_getpages_from_fscache: submitted\n");

		return ret;

	case -ENOBUFS: /* some pages aren't cached and can't be */
	case -ENODATA: /* some pages aren't cached */
		dfprintk(FSCACHE,
			 "NFS: nfs_getpages_from_fscache: no page: %d\n", ret);
		return 1;

	default:
		dfprintk(FSCACHE,
			 "NFS: nfs_getpages_from_fscache: ret  %d\n", ret);
	}

	return ret;
}

/*
 * Store a newly fetched page in fscache
 * - PG_fscache must be set on the page
 */
void __nfs_readpage_to_fscache(struct inode *inode, struct page *page, int sync)
{
	int ret;

	dfprintk(FSCACHE,
		 "NFS: readpage_to_fscache(fsc:%p/p:%p(i:%lx f:%lx)/%d)\n",
		 nfs_i_fscache(inode), page, page->index, page->flags, sync);

	ret = fscache_write_page(nfs_i_fscache(inode), page,
				 inode->i_size, GFP_KERNEL);
	dfprintk(FSCACHE,
		 "NFS:     readpage_to_fscache: p:%p(i:%lu f:%lx) ret %d\n",
		 page, page->index, page->flags, ret);

	if (ret != 0) {
		fscache_uncache_page(nfs_i_fscache(inode), page);
		nfs_inc_fscache_stats(inode,
				      NFSIOS_FSCACHE_PAGES_WRITTEN_FAIL);
		nfs_inc_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_UNCACHED);
	} else {
		nfs_inc_fscache_stats(inode,
				      NFSIOS_FSCACHE_PAGES_WRITTEN_OK);
	}
}
Commit	Line	Data
b4d0d230	1	// SPDX-License-Identifier: GPL-2.0-or-later
14727281 DH	2	/* NFS filesystem cache interface
	3	*
	4	* Copyright (C) 2008 Red Hat, Inc. All Rights Reserved.
	5	* Written by David Howells (dhowells@redhat.com)
14727281 DH	6	*/
	7
	8	#include <linux/init.h>
	9	#include <linux/kernel.h>
	10	#include <linux/sched.h>
	11	#include <linux/mm.h>
	12	#include <linux/nfs_fs.h>
	13	#include <linux/nfs_fs_sb.h>
	14	#include <linux/in6.h>
	15	#include <linux/seq_file.h>
5a0e3ad6	16	#include <linux/slab.h>
402cb8dd	17	#include <linux/iversion.h>
14727281 DH	18
14727281 DH	19	#include "internal.h"
545db45f	20	#include "iostat.h"
14727281 DH	21	#include "fscache.h"
	22
	23	#define NFSDBG_FACILITY NFSDBG_FSCACHE
	24
08734048 DH	25	static struct rb_root nfs_fscache_keys = RB_ROOT;
	26	static DEFINE_SPINLOCK(nfs_fscache_keys_lock);
	27
402cb8dd DH	28	/*
	29	* Layout of the key for an NFS server cache object.
	30	*/
	31	struct nfs_server_key {
	32	struct {
	33	uint16_t nfsversion; /* NFS protocol version */
	34	uint16_t family; /* address family */
	35	__be16 port; /* IP port */
	36	} hdr;
	37	union {
	38	struct in_addr ipv4_addr; /* IPv4 address */
	39	struct in6_addr ipv6_addr; /* IPv6 address */
	40	};
	41	} __packed;
	42
14727281 DH	43	/*
	44	* Get the per-client index cookie for an NFS client if the appropriate mount
	45	* flag was set
	46	* - We always try and get an index cookie for the client, but get filehandle
	47	* cookies on a per-superblock basis, depending on the mount flags
	48	*/
	49	void nfs_fscache_get_client_cookie(struct nfs_client *clp)
	50	{
402cb8dd DH	51	const struct sockaddr_in6 sin6 = (struct sockaddr_in6 ) &clp->cl_addr;
	52	const struct sockaddr_in sin = (struct sockaddr_in ) &clp->cl_addr;
	53	struct nfs_server_key key;
	54	uint16_t len = sizeof(key.hdr);
	55
	56	memset(&key, 0, sizeof(key));
	57	key.hdr.nfsversion = clp->rpc_ops->version;
	58	key.hdr.family = clp->cl_addr.ss_family;
	59
	60	switch (clp->cl_addr.ss_family) {
	61	case AF_INET:
	62	key.hdr.port = sin->sin_port;
	63	key.ipv4_addr = sin->sin_addr;
	64	len += sizeof(key.ipv4_addr);
	65	break;
	66
	67	case AF_INET6:
	68	key.hdr.port = sin6->sin6_port;
	69	key.ipv6_addr = sin6->sin6_addr;
	70	len += sizeof(key.ipv6_addr);
	71	break;
	72
	73	default:
	74	printk(KERN_WARNING "NFS: Unknown network family '%d'\n",
	75	clp->cl_addr.ss_family);
	76	clp->fscache = NULL;
	77	return;
	78	}
	79
14727281 DH	80	/* create a cache index for looking up filehandles */
	81	clp->fscache = fscache_acquire_cookie(nfs_fscache_netfs.primary_index,
	82	&nfs_fscache_server_index_def,
402cb8dd DH	83	&key, len,
402cb8dd DH	84	NULL, 0,
ee1235a9	85	clp, 0, true);
14727281 DH	86	dfprintk(FSCACHE, "NFS: get client cookie (0x%p/0x%p)\n",
	87	clp, clp->fscache);
	88	}
	89
	90	/*
	91	* Dispose of a per-client cookie
	92	*/
	93	void nfs_fscache_release_client_cookie(struct nfs_client *clp)
	94	{
	95	dfprintk(FSCACHE, "NFS: releasing client cookie (0x%p/0x%p)\n",
	96	clp, clp->fscache);
	97
402cb8dd	98	fscache_relinquish_cookie(clp->fscache, NULL, false);
14727281 DH	99	clp->fscache = NULL;
14727281 DH	100	}
08734048 DH	101
	102	/*
	103	* Get the cache cookie for an NFS superblock. We have to handle
	104	* uniquification here because the cache doesn't do it for us.
2df54806 DH	105	*
	106	* The default uniquifier is just an empty string, but it may be overridden
	107	* either by the 'fsc=xxx' option to mount, or by inheriting it from the parent
	108	* superblock across an automount point of some nature.
08734048	109	*/
2311b943	110	void nfs_fscache_get_super_cookie(struct super_block sb, const char uniq, int ulen)
08734048 DH	111	{
	112	struct nfs_fscache_key key, xkey;
	113	struct nfs_server *nfss = NFS_SB(sb);
	114	struct rb_node *p, parent;
2311b943	115	int diff;
2df54806 DH	116
	117	if (!uniq) {
	118	uniq = "";
	119	ulen = 1;
	120	}
	121
08734048 DH	122	key = kzalloc(sizeof(*key) + ulen, GFP_KERNEL);
	123	if (!key)
	124	return;
	125
	126	key->nfs_client = nfss->nfs_client;
	127	key->key.super.s_flags = sb->s_flags & NFS_MS_MASK;
	128	key->key.nfs_server.flags = nfss->flags;
	129	key->key.nfs_server.rsize = nfss->rsize;
	130	key->key.nfs_server.wsize = nfss->wsize;
	131	key->key.nfs_server.acregmin = nfss->acregmin;
	132	key->key.nfs_server.acregmax = nfss->acregmax;
	133	key->key.nfs_server.acdirmin = nfss->acdirmin;
	134	key->key.nfs_server.acdirmax = nfss->acdirmax;
	135	key->key.nfs_server.fsid = nfss->fsid;
	136	key->key.rpc_auth.au_flavor = nfss->client->cl_auth->au_flavor;
	137
	138	key->key.uniq_len = ulen;
	139	memcpy(key->key.uniquifier, uniq, ulen);
	140
	141	spin_lock(&nfs_fscache_keys_lock);
	142	p = &nfs_fscache_keys.rb_node;
	143	parent = NULL;
	144	while (*p) {
	145	parent = *p;
	146	xkey = rb_entry(parent, struct nfs_fscache_key, node);
	147
	148	if (key->nfs_client < xkey->nfs_client)
	149	goto go_left;
	150	if (key->nfs_client > xkey->nfs_client)
	151	goto go_right;
	152
	153	diff = memcmp(&key->key, &xkey->key, sizeof(key->key));
	154	if (diff < 0)
	155	goto go_left;
	156	if (diff > 0)
	157	goto go_right;
	158
	159	if (key->key.uniq_len == 0)
	160	goto non_unique;
	161	diff = memcmp(key->key.uniquifier,
	162	xkey->key.uniquifier,
	163	key->key.uniq_len);
	164	if (diff < 0)
	165	goto go_left;
	166	if (diff > 0)
	167	goto go_right;
	168	goto non_unique;
	169
	170	go_left:
	171	p = &(*p)->rb_left;
	172	continue;
	173	go_right:
	174	p = &(*p)->rb_right;
	175	}
	176
	177	rb_link_node(&key->node, parent, p);
	178	rb_insert_color(&key->node, &nfs_fscache_keys);
	179	spin_unlock(&nfs_fscache_keys_lock);
	180	nfss->fscache_key = key;
	181
	182	/* create a cache index for looking up filehandles */
	183	nfss->fscache = fscache_acquire_cookie(nfss->nfs_client->fscache,
	184	&nfs_fscache_super_index_def,
402cb8dd DH	185	key, sizeof(*key) + ulen,
402cb8dd DH	186	NULL, 0,
ee1235a9	187	nfss, 0, true);
08734048 DH	188	dfprintk(FSCACHE, "NFS: get superblock cookie (0x%p/0x%p)\n",
	189	nfss, nfss->fscache);
	190	return;
	191
	192	non_unique:
	193	spin_unlock(&nfs_fscache_keys_lock);
	194	kfree(key);
	195	nfss->fscache_key = NULL;
	196	nfss->fscache = NULL;
	197	printk(KERN_WARNING "NFS:"
	198	" Cache request denied due to non-unique superblock keys\n");
	199	}
	200
	201	/*
	202	* release a per-superblock cookie
	203	*/
	204	void nfs_fscache_release_super_cookie(struct super_block *sb)
	205	{
	206	struct nfs_server *nfss = NFS_SB(sb);
	207
	208	dfprintk(FSCACHE, "NFS: releasing superblock cookie (0x%p/0x%p)\n",
	209	nfss, nfss->fscache);
	210
402cb8dd	211	fscache_relinquish_cookie(nfss->fscache, NULL, false);
08734048 DH	212	nfss->fscache = NULL;
	213
	214	if (nfss->fscache_key) {
	215	spin_lock(&nfs_fscache_keys_lock);
	216	rb_erase(&nfss->fscache_key->node, &nfs_fscache_keys);
	217	spin_unlock(&nfs_fscache_keys_lock);
	218	kfree(nfss->fscache_key);
	219	nfss->fscache_key = NULL;
	220	}
	221	}
ef79c097 DH	222
	223	/*
	224	* Initialise the per-inode cache cookie pointer for an NFS inode.
	225	*/
f1fe29b4	226	void nfs_fscache_init_inode(struct inode *inode)
ef79c097	227	{
402cb8dd	228	struct nfs_fscache_inode_auxdata auxdata;
ef79c097 DH	229	struct nfs_inode *nfsi = NFS_I(inode);
ef79c097 DH	230
f1fe29b4 DH	231	nfsi->fscache = NULL;
f1fe29b4 DH	232	if (!S_ISREG(inode->i_mode))
ef79c097	233	return;
402cb8dd DH	234
402cb8dd DH	235	memset(&auxdata, 0, sizeof(auxdata));
95582b00 DD	236	auxdata.mtime = timespec64_to_timespec(nfsi->vfs_inode.i_mtime);
95582b00 DD	237	auxdata.ctime = timespec64_to_timespec(nfsi->vfs_inode.i_ctime);
402cb8dd DH	238
	239	if (NFS_SERVER(&nfsi->vfs_inode)->nfs_client->rpc_ops->version == 4)
	240	auxdata.change_attr = inode_peek_iversion_raw(&nfsi->vfs_inode);
	241
f1fe29b4 DH	242	nfsi->fscache = fscache_acquire_cookie(NFS_SB(inode->i_sb)->fscache,
f1fe29b4 DH	243	&nfs_fscache_inode_object_def,
402cb8dd DH	244	nfsi->fh.data, nfsi->fh.size,
402cb8dd DH	245	&auxdata, sizeof(auxdata),
ee1235a9	246	nfsi, nfsi->vfs_inode.i_size, false);
ef79c097 DH	247	}
	248
	249	/*
	250	* Release a per-inode cookie.
	251	*/
f1fe29b4	252	void nfs_fscache_clear_inode(struct inode *inode)
ef79c097	253	{
402cb8dd	254	struct nfs_fscache_inode_auxdata auxdata;
ef79c097	255	struct nfs_inode *nfsi = NFS_I(inode);
f1fe29b4	256	struct fscache_cookie *cookie = nfs_i_fscache(inode);
ef79c097	257
f1fe29b4	258	dfprintk(FSCACHE, "NFS: clear cookie (0x%p/0x%p)\n", nfsi, cookie);
ef79c097	259
402cb8dd	260	memset(&auxdata, 0, sizeof(auxdata));
95582b00 DD	261	auxdata.mtime = timespec64_to_timespec(nfsi->vfs_inode.i_mtime);
95582b00 DD	262	auxdata.ctime = timespec64_to_timespec(nfsi->vfs_inode.i_ctime);
402cb8dd	263	fscache_relinquish_cookie(cookie, &auxdata, false);
ef79c097 DH	264	nfsi->fscache = NULL;
	265	}
	266
f1fe29b4	267	static bool nfs_fscache_can_enable(void *data)
ef79c097	268	{
f1fe29b4	269	struct inode *inode = data;
ef79c097	270
f1fe29b4	271	return !inode_is_open_for_write(inode);
ef79c097 DH	272	}
	273
	274	/*
f1fe29b4 DH	275	* Enable or disable caching for a file that is being opened as appropriate.
	276	* The cookie is allocated when the inode is initialised, but is not enabled at
	277	* that time. Enablement is deferred to file-open time to avoid stat() and
	278	* access() thrashing the cache.
	279	*
	280	* For now, with NFS, only regular files that are open read-only will be able
	281	* to use the cache.
	282	*
	283	* We enable the cache for an inode if we open it read-only and it isn't
	284	* currently open for writing. We disable the cache if the inode is open
	285	* write-only.
	286	*
	287	* The caller uses the file struct to pin i_writecount on the inode before
	288	* calling us when a file is opened for writing, so we can make use of that.
	289	*
	290	* Note that this may be invoked multiple times in parallel by parallel
	291	* nfs_open() functions.
ef79c097	292	*/
f1fe29b4	293	void nfs_fscache_open_file(struct inode inode, struct file filp)
ef79c097	294	{
402cb8dd	295	struct nfs_fscache_inode_auxdata auxdata;
ef79c097	296	struct nfs_inode *nfsi = NFS_I(inode);
f1fe29b4	297	struct fscache_cookie *cookie = nfs_i_fscache(inode);
ef79c097	298
f1fe29b4 DH	299	if (!fscache_cookie_valid(cookie))
f1fe29b4 DH	300	return;
ef79c097	301
402cb8dd	302	memset(&auxdata, 0, sizeof(auxdata));
95582b00 DD	303	auxdata.mtime = timespec64_to_timespec(nfsi->vfs_inode.i_mtime);
95582b00 DD	304	auxdata.ctime = timespec64_to_timespec(nfsi->vfs_inode.i_ctime);
402cb8dd	305
f1fe29b4 DH	306	if (inode_is_open_for_write(inode)) {
	307	dfprintk(FSCACHE, "NFS: nfsi 0x%p disabling cache\n", nfsi);
	308	clear_bit(NFS_INO_FSCACHE, &nfsi->flags);
402cb8dd	309	fscache_disable_cookie(cookie, &auxdata, true);
f1fe29b4 DH	310	fscache_uncache_all_inode_pages(cookie, inode);
	311	} else {
	312	dfprintk(FSCACHE, "NFS: nfsi 0x%p enabling cache\n", nfsi);
ee1235a9	313	fscache_enable_cookie(cookie, &auxdata, nfsi->vfs_inode.i_size,
402cb8dd	314	nfs_fscache_can_enable, inode);
f1fe29b4 DH	315	if (fscache_cookie_enabled(cookie))
f1fe29b4 DH	316	set_bit(NFS_INO_FSCACHE, &NFS_I(inode)->flags);
ef79c097	317	}
ef79c097	318	}
f1fe29b4	319	EXPORT_SYMBOL_GPL(nfs_fscache_open_file);
545db45f DH	320
	321	/*
	322	* Release the caching state associated with a page, if the page isn't busy
	323	* interacting with the cache.
	324	* - Returns true (can release page) or false (page busy).
	325	*/
	326	int nfs_fscache_release_page(struct page *page, gfp_t gfp)
	327	{
545db45f	328	if (PageFsCache(page)) {
f1fe29b4	329	struct fscache_cookie *cookie = nfs_i_fscache(page->mapping->host);
2c174009 TM	330
2c174009 TM	331	BUG_ON(!cookie);
545db45f	332	dfprintk(FSCACHE, "NFS: fscache releasepage (0x%p/0x%p/0x%p)\n",
f1fe29b4	333	cookie, page, NFS_I(page->mapping->host));
545db45f	334
201a1542 DH	335	if (!fscache_maybe_release_page(cookie, page, gfp))
	336	return 0;
	337
e9f456ca LR	338	nfs_inc_fscache_stats(page->mapping->host,
e9f456ca LR	339	NFSIOS_FSCACHE_PAGES_UNCACHED);
545db45f DH	340	}
	341
	342	return 1;
	343	}
	344
	345	/*
	346	* Release the caching state associated with a page if undergoing complete page
	347	* invalidation.
	348	*/
	349	void __nfs_fscache_invalidate_page(struct page page, struct inode inode)
	350	{
f1fe29b4	351	struct fscache_cookie *cookie = nfs_i_fscache(inode);
545db45f DH	352
	353	BUG_ON(!cookie);
	354
	355	dfprintk(FSCACHE, "NFS: fscache invalidatepage (0x%p/0x%p/0x%p)\n",
f1fe29b4	356	cookie, page, NFS_I(inode));
545db45f DH	357
	358	fscache_wait_on_page_write(cookie, page);
	359
	360	BUG_ON(!PageLocked(page));
	361	fscache_uncache_page(cookie, page);
e9f456ca LR	362	nfs_inc_fscache_stats(page->mapping->host,
e9f456ca LR	363	NFSIOS_FSCACHE_PAGES_UNCACHED);
545db45f	364	}
9a9fc1c0 DH	365
	366	/*
	367	* Handle completion of a page being read from the cache.
	368	* - Called in process (keventd) context.
	369	*/
	370	static void nfs_readpage_from_fscache_complete(struct page *page,
	371	void *context,
	372	int error)
	373	{
	374	dfprintk(FSCACHE,
	375	"NFS: readpage_from_fscache_complete (0x%p/0x%p/%d)\n",
	376	page, context, error);
	377
	378	/* if the read completes with an error, we just unlock the page and let
	379	* the VM reissue the readpage */
	380	if (!error) {
	381	SetPageUptodate(page);
	382	unlock_page(page);
	383	} else {
	384	error = nfs_readpage_async(context, page->mapping->host, page);
	385	if (error)
	386	unlock_page(page);
	387	}
	388	}
	389
	390	/*
	391	* Retrieve a page from fscache
	392	*/
	393	int __nfs_readpage_from_fscache(struct nfs_open_context *ctx,
	394	struct inode inode, struct page page)
	395	{
	396	int ret;
	397
	398	dfprintk(FSCACHE,
	399	"NFS: readpage_from_fscache(fsc:%p/p:%p(i:%lx f:%lx)/0x%p)\n",
f1fe29b4	400	nfs_i_fscache(inode), page, page->index, page->flags, inode);
9a9fc1c0	401
f1fe29b4	402	ret = fscache_read_or_alloc_page(nfs_i_fscache(inode),
9a9fc1c0 DH	403	page,
	404	nfs_readpage_from_fscache_complete,
	405	ctx,
	406	GFP_KERNEL);
	407
	408	switch (ret) {
	409	case 0: /* read BIO submitted (page in fscache) */
	410	dfprintk(FSCACHE,
	411	"NFS: readpage_from_fscache: BIO submitted\n");
e9f456ca	412	nfs_inc_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_READ_OK);
9a9fc1c0 DH	413	return ret;
	414
	415	case -ENOBUFS: /* inode not in cache */
	416	case -ENODATA: /* page not in cache */
e9f456ca	417	nfs_inc_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_READ_FAIL);
9a9fc1c0 DH	418	dfprintk(FSCACHE,
	419	"NFS: readpage_from_fscache %d\n", ret);
	420	return 1;
	421
	422	default:
	423	dfprintk(FSCACHE, "NFS: readpage_from_fscache %d\n", ret);
e9f456ca	424	nfs_inc_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_READ_FAIL);
9a9fc1c0 DH	425	}
	426	return ret;
	427	}
	428
	429	/*
	430	* Retrieve a set of pages from fscache
	431	*/
	432	int __nfs_readpages_from_fscache(struct nfs_open_context *ctx,
	433	struct inode *inode,
	434	struct address_space *mapping,
	435	struct list_head *pages,
	436	unsigned *nr_pages)
	437	{
0f15c53d CL	438	unsigned npages = *nr_pages;
0f15c53d CL	439	int ret;
9a9fc1c0 DH	440
9a9fc1c0 DH	441	dfprintk(FSCACHE, "NFS: nfs_getpages_from_fscache (0x%p/%u/0x%p)\n",
f1fe29b4	442	nfs_i_fscache(inode), npages, inode);
9a9fc1c0	443
f1fe29b4	444	ret = fscache_read_or_alloc_pages(nfs_i_fscache(inode),
9a9fc1c0 DH	445	mapping, pages, nr_pages,
	446	nfs_readpage_from_fscache_complete,
	447	ctx,
	448	mapping_gfp_mask(mapping));
	449	if (*nr_pages < npages)
	450	nfs_add_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_READ_OK,
	451	npages);
	452	if (*nr_pages > 0)
	453	nfs_add_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_READ_FAIL,
	454	*nr_pages);
	455
	456	switch (ret) {
	457	case 0: /* read submitted to the cache for all pages */
	458	BUG_ON(!list_empty(pages));
	459	BUG_ON(*nr_pages != 0);
	460	dfprintk(FSCACHE,
	461	"NFS: nfs_getpages_from_fscache: submitted\n");
	462
	463	return ret;
	464
	465	case -ENOBUFS: /* some pages aren't cached and can't be */
	466	case -ENODATA: /* some pages aren't cached */
	467	dfprintk(FSCACHE,
	468	"NFS: nfs_getpages_from_fscache: no page: %d\n", ret);
	469	return 1;
	470
	471	default:
	472	dfprintk(FSCACHE,
	473	"NFS: nfs_getpages_from_fscache: ret %d\n", ret);
	474	}
	475
	476	return ret;
	477	}
7f8e05f6 DH	478
	479	/*
	480	* Store a newly fetched page in fscache
	481	* - PG_fscache must be set on the page
	482	*/
	483	void __nfs_readpage_to_fscache(struct inode inode, struct page page, int sync)
	484	{
	485	int ret;
	486
	487	dfprintk(FSCACHE,
	488	"NFS: readpage_to_fscache(fsc:%p/p:%p(i:%lx f:%lx)/%d)\n",
f1fe29b4	489	nfs_i_fscache(inode), page, page->index, page->flags, sync);
7f8e05f6	490
ee1235a9 DH	491	ret = fscache_write_page(nfs_i_fscache(inode), page,
ee1235a9 DH	492	inode->i_size, GFP_KERNEL);
7f8e05f6 DH	493	dfprintk(FSCACHE,
	494	"NFS: readpage_to_fscache: p:%p(i:%lu f:%lx) ret %d\n",
	495	page, page->index, page->flags, ret);
	496
	497	if (ret != 0) {
f1fe29b4	498	fscache_uncache_page(nfs_i_fscache(inode), page);
e9f456ca LR	499	nfs_inc_fscache_stats(inode,
	500	NFSIOS_FSCACHE_PAGES_WRITTEN_FAIL);
	501	nfs_inc_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_UNCACHED);
7f8e05f6	502	} else {
e9f456ca LR	503	nfs_inc_fscache_stats(inode,
e9f456ca LR	504	NFSIOS_FSCACHE_PAGES_WRITTEN_OK);
7f8e05f6 DH	505	}
7f8e05f6 DH	506	}