nfs: Convert to new fscache volume/cookie API

Change the nfs filesystem to support fscache's indexing rewrite and
reenable caching in nfs.

The following changes have been made:

 (1) The fscache_netfs struct is no more, and there's no need to register
     the filesystem as a whole.

 (2) The session cookie is now an fscache_volume cookie, allocated with
     fscache_acquire_volume().  That takes three parameters: a string
     representing the "volume" in the index, a string naming the cache to
     use (or NULL) and a u64 that conveys coherency metadata for the
     volume.

     For nfs, I've made it render the volume name string as:

        "nfs,<ver>,<family>,<address>,<port>,<fsidH>,<fsidL>*<,param>[,<uniq>]"

 (3) The fscache_cookie_def is no more and needed information is passed
     directly to fscache_acquire_cookie().  The cache no longer calls back
     into the filesystem, but rather metadata changes are indicated at
     other times.

     fscache_acquire_cookie() is passed the same keying and coherency
     information as before.

 (4) fscache_enable/disable_cookie() have been removed.

     Call fscache_use_cookie() and fscache_unuse_cookie() when a file is
     opened or closed to prevent a cache file from being culled and to keep
     resources to hand that are needed to do I/O.

     If a file is opened for writing, we invalidate it with
     FSCACHE_INVAL_DIO_WRITE in lieu of doing writeback to the cache,
     thereby making it cease caching until all currently open files are
     closed.  This should give the same behaviour as the uptream code.
     Making the cache store local modifications isn't straightforward for
     NFS, so that's left for future patches.

 (5) fscache_invalidate() now needs to be given uptodate auxiliary data and
     a file size.  It also takes a flag to indicate if this was due to a
     DIO write.

 (6) Call nfs_fscache_invalidate() with FSCACHE_INVAL_DIO_WRITE on a file
     to which a DIO write is made.

 (7) Call fscache_note_page_release() from nfs_release_page().

 (8) Use a killable wait in nfs_vm_page_mkwrite() when waiting for
     PG_fscache to be cleared.

 (9) The functions to read and write data to/from the cache are stubbed out
     pending a conversion to use netfslib.

Changes
=======
ver #3:
 - Added missing =n fallback for nfs_fscache_release_file()[1][2].

ver #2:
 - Use gfpflags_allow_blocking() rather than using flag directly.
 - fscache_acquire_volume() now returns errors.
 - Remove NFS_INO_FSCACHE as it's no longer used.
 - Need to unuse a cookie on file-release, not inode-clear.

Signed-off-by: Dave Wysochanski <dwysocha@redhat.com>
Co-developed-by: David Howells <dhowells@redhat.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Tested-by: Dave Wysochanski <dwysocha@redhat.com>
Acked-by: Jeff Layton <jlayton@kernel.org>
cc: Trond Myklebust <trond.myklebust@hammerspace.com>
cc: Anna Schumaker <anna.schumaker@netapp.com>
cc: linux-nfs@vger.kernel.org
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/202112100804.nksO8K4u-lkp@intel.com/ [1]
Link: https://lore.kernel.org/r/202112100957.2oEDT20W-lkp@intel.com/ [2]
Link: https://lore.kernel.org/r/163819668938.215744.14448852181937731615.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/163906979003.143852.2601189243864854724.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/163967182112.1823006.7791504655391213379.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/164021575950.640689.12069642327533368467.stgit@warthog.procyon.org.uk/ # v4

1 files changed, 105 insertions, 329 deletions

diff --git a/fs/nfs/fscache.c b/fs/nfs/fscache.c
index d743629e05e1..fac6438477a0 100644
--- a/fs/nfs/fscache.c
+++ b/fs/nfs/fscache.c
@@ -22,24 +22,18 @@
 
 #define NFSDBG_FACILITY		NFSDBG_FSCACHE
 
-static struct rb_root nfs_fscache_keys = RB_ROOT;
-static DEFINE_SPINLOCK(nfs_fscache_keys_lock);
+#define NFS_MAX_KEY_LEN 1000
 
-/*
- * Layout of the key for an NFS server cache object.
- */
-struct nfs_server_key {
-	struct {
-		uint16_t	nfsversion;		/* NFS protocol version */
-		uint32_t	minorversion;		/* NFSv4 minor 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;
+static bool nfs_append_int(char *key, int *_len, unsigned long long x)
+{
+	if (*_len > NFS_MAX_KEY_LEN)
+		return false;
+	if (x == 0)
+		key[(*_len)++] = ',';
+	else
+		*_len += sprintf(key + *_len, ",%llx", x);
+	return true;
+}
 
 /*
  * Get the per-client index cookie for an NFS client if the appropriate mount
@@ -47,160 +41,108 @@ struct nfs_server_key {
  * - 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)
+static bool nfs_fscache_get_client_key(struct nfs_client *clp,
+				       char *key, int *_len)
 {
 	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.minorversion = clp->cl_minorversion;
-	key.hdr.family = clp->cl_addr.ss_family;
+	*_len += snprintf(key + *_len, NFS_MAX_KEY_LEN - *_len,
+			  ",%u.%u,%x",
+			  clp->rpc_ops->version,
+			  clp->cl_minorversion,
+			  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;
+		if (!nfs_append_int(key, _len, sin->sin_port) ||
+		    !nfs_append_int(key, _len, sin->sin_addr.s_addr))
+			return false;
+		return true;
 
 	case AF_INET6:
-		key.hdr.port = sin6->sin6_port;
-		key.ipv6_addr = sin6->sin6_addr;
-		len += sizeof(key.ipv6_addr);
-		break;
+		if (!nfs_append_int(key, _len, sin6->sin6_port) ||
+		    !nfs_append_int(key, _len, sin6->sin6_addr.s6_addr32[0]) ||
+		    !nfs_append_int(key, _len, sin6->sin6_addr.s6_addr32[1]) ||
+		    !nfs_append_int(key, _len, sin6->sin6_addr.s6_addr32[2]) ||
+		    !nfs_append_int(key, _len, sin6->sin6_addr.s6_addr32[3]))
+			return false;
+		return true;
 
 	default:
 		printk(KERN_WARNING "NFS: Unknown network family '%d'\n",
 		       clp->cl_addr.ss_family);
-		clp->fscache = NULL;
-		return;
+		return false;
 	}
-
-	/* 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.
+ * Get the cache cookie for an NFS superblock.
  *
  * 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)
+int nfs_fscache_get_super_cookie(struct super_block *sb, const char *uniq, int ulen)
 {
-	struct nfs_fscache_key *key, *xkey;
+	struct fscache_volume *vcookie;
 	struct nfs_server *nfss = NFS_SB(sb);
-	struct rb_node **p, *parent;
-	int diff;
+	unsigned int len = 3;
+	char *key;
 
-	nfss->fscache_key = NULL;
-	nfss->fscache = NULL;
-	if (!uniq) {
-		uniq = "";
-		ulen = 1;
+	if (uniq) {
+		nfss->fscache_uniq = kmemdup_nul(uniq, ulen, GFP_KERNEL);
+		if (!nfss->fscache_uniq)
+			return -ENOMEM;
 	}
 
-	key = kzalloc(sizeof(*key) + ulen, GFP_KERNEL);
+	key = kmalloc(NFS_MAX_KEY_LEN + 24, GFP_KERNEL);
 	if (!key)
-		return;
-
-	key->nfs_client = nfss->nfs_client;
-	key->key.super.s_flags = sb->s_flags & NFS_SB_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;
+		return -ENOMEM;
+
+	memcpy(key, "nfs", 3);
+	if (!nfs_fscache_get_client_key(nfss->nfs_client, key, &len) ||
+	    !nfs_append_int(key, &len, nfss->fsid.major) ||
+	    !nfs_append_int(key, &len, nfss->fsid.minor) ||
+	    !nfs_append_int(key, &len, sb->s_flags & NFS_SB_MASK) ||
+	    !nfs_append_int(key, &len, nfss->flags) ||
+	    !nfs_append_int(key, &len, nfss->rsize) ||
+	    !nfs_append_int(key, &len, nfss->wsize) ||
+	    !nfs_append_int(key, &len, nfss->acregmin) ||
+	    !nfs_append_int(key, &len, nfss->acregmax) ||
+	    !nfs_append_int(key, &len, nfss->acdirmin) ||
+	    !nfs_append_int(key, &len, nfss->acdirmax) ||
+	    !nfs_append_int(key, &len, nfss->client->cl_auth->au_flavor))
+		goto out;
+
+	if (ulen > 0) {
+		if (ulen > NFS_MAX_KEY_LEN - len)
+			goto out;
+		key[len++] = ',';
+		memcpy(key + len, uniq, ulen);
+		len += ulen;
 	}
-
-	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;
+	key[len] = 0;
 
 	/* create a cache index for looking up filehandles */
-	nfss->fscache = fscache_acquire_cookie(nfss->nfs_client->fscache,
-					       &nfs_fscache_super_index_def,
-					       &key->key,
-					       sizeof(key->key) + ulen,
-					       NULL, 0,
-					       nfss, 0, true);
+	vcookie = fscache_acquire_volume(key,
+					 NULL, /* preferred_cache */
+					 NULL, 0 /* coherency_data */);
 	dfprintk(FSCACHE, "NFS: get superblock cookie (0x%p/0x%p)\n",
-		 nfss, nfss->fscache);
-	return;
+		 nfss, vcookie);
+	if (IS_ERR(vcookie)) {
+		if (vcookie != ERR_PTR(-EBUSY)) {
+			kfree(key);
+			return PTR_ERR(vcookie);
+		}
+		pr_err("NFS: Cache volume key already in use (%s)\n", key);
+		vcookie = NULL;
+	}
+	nfss->fscache = vcookie;
 
-non_unique:
-	spin_unlock(&nfs_fscache_keys_lock);
+out:
 	kfree(key);
-	nfss->fscache_key = NULL;
-	nfss->fscache = NULL;
-	printk(KERN_WARNING "NFS:"
-	       " Cache request denied due to non-unique superblock keys\n");
+	return 0;
 }
 
 /*
@@ -213,29 +155,9 @@ void nfs_fscache_release_super_cookie(struct super_block *sb)
 	dfprintk(FSCACHE, "NFS: releasing superblock cookie (0x%p/0x%p)\n",
 		 nfss, nfss->fscache);
 
-	fscache_relinquish_cookie(nfss->fscache, NULL, false);
+	fscache_relinquish_volume(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;
-	}
-}
-
-static 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);
+	kfree(nfss->fscache_uniq);
 }
 
 /*
@@ -254,10 +176,12 @@ void nfs_fscache_init_inode(struct inode *inode)
 	nfs_fscache_update_auxdata(&auxdata, nfsi);
 
 	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);
+					       0,
+					       nfsi->fh.data, /* index_key */
+					       nfsi->fh.size,
+					       &auxdata,      /* aux_data */
+					       sizeof(auxdata),
+					       i_size_read(&nfsi->vfs_inode));
 }
 
 /*
@@ -265,24 +189,15 @@ void nfs_fscache_init_inode(struct inode *inode)
  */
 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);
 
-	nfs_fscache_update_auxdata(&auxdata, nfsi);
-	fscache_relinquish_cookie(cookie, &auxdata, false);
+	fscache_relinquish_cookie(cookie, 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
@@ -307,93 +222,31 @@ 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);
+	bool open_for_write = inode_is_open_for_write(inode);
 
 	if (!fscache_cookie_valid(cookie))
 		return;
 
-	nfs_fscache_update_auxdata(&auxdata, nfsi);
-
-	if (inode_is_open_for_write(inode)) {
+	fscache_use_cookie(cookie, open_for_write);
+	if (open_for_write) {
 		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);
+		nfs_fscache_update_auxdata(&auxdata, nfsi);
+		fscache_invalidate(cookie, &auxdata, i_size_read(inode),
+				   FSCACHE_INVAL_DIO_WRITE);
 	}
 }
 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)
+void nfs_fscache_release_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);
 
-	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, mark the page with PG_checked,
-	 * unlock the page, and let the VM reissue the readpage.
-	 */
-	if (!error)
-		SetPageUptodate(page);
-	else
-		SetPageChecked(page);
-	unlock_page(page);
+	if (fscache_cookie_valid(cookie)) {
+		nfs_fscache_update_auxdata(&auxdata, nfsi);
+		fscache_unuse_cookie(cookie, &auxdata, NULL);
+	}
 }
 
 /*
@@ -402,8 +255,6 @@ static void nfs_readpage_from_fscache_complete(struct page *page,
 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);
@@ -413,31 +264,7 @@ int __nfs_readpage_from_fscache(struct nfs_open_context *ctx,
 		return 1;
 	}
 
-	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;
+	return -ENOBUFS; // TODO: Use netfslib
 }
 
 /*
@@ -449,45 +276,10 @@ int __nfs_readpages_from_fscache(struct nfs_open_context *ctx,
 				 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;
+		 nfs_i_fscache(inode), *nr_pages, inode);
 
-	default:
-		dfprintk(FSCACHE,
-			 "NFS: nfs_getpages_from_fscache: ret  %d\n", ret);
-	}
-
-	return ret;
+	return -ENOBUFS; // TODO: Use netfslib
 }
 
 /*
@@ -496,25 +288,9 @@ int __nfs_readpages_from_fscache(struct nfs_open_context *ctx,
  */
 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);
-	}
+	return; // TODO: Use netfslib
 }