Adding upstream version 6.1.76.upstream/6.1.76upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 2447 insertions, 0 deletions

diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
new file mode 100644
index 000000000..e0c1fb98f
--- /dev/null
+++ b/fs/nfs/inode.c
@@ -0,0 +1,2447 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *  linux/fs/nfs/inode.c
+ *
+ *  Copyright (C) 1992  Rick Sladkey
+ *
+ *  nfs inode and superblock handling functions
+ *
+ *  Modularised by Alan Cox <alan@lxorguk.ukuu.org.uk>, while hacking some
+ *  experimental NFS changes. Modularisation taken straight from SYS5 fs.
+ *
+ *  Change to nfs_read_super() to permit NFS mounts to multi-homed hosts.
+ *  J.S.Peatfield@damtp.cam.ac.uk
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/sched/signal.h>
+#include <linux/time.h>
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/string.h>
+#include <linux/stat.h>
+#include <linux/errno.h>
+#include <linux/unistd.h>
+#include <linux/sunrpc/clnt.h>
+#include <linux/sunrpc/stats.h>
+#include <linux/sunrpc/metrics.h>
+#include <linux/nfs_fs.h>
+#include <linux/nfs_mount.h>
+#include <linux/nfs4_mount.h>
+#include <linux/lockd/bind.h>
+#include <linux/seq_file.h>
+#include <linux/mount.h>
+#include <linux/vfs.h>
+#include <linux/inet.h>
+#include <linux/nfs_xdr.h>
+#include <linux/slab.h>
+#include <linux/compat.h>
+#include <linux/freezer.h>
+#include <linux/uaccess.h>
+#include <linux/iversion.h>
+
+#include "nfs4_fs.h"
+#include "callback.h"
+#include "delegation.h"
+#include "iostat.h"
+#include "internal.h"
+#include "fscache.h"
+#include "pnfs.h"
+#include "nfs.h"
+#include "netns.h"
+#include "sysfs.h"
+
+#include "nfstrace.h"
+
+#define NFSDBG_FACILITY		NFSDBG_VFS
+
+#define NFS_64_BIT_INODE_NUMBERS_ENABLED	1
+
+/* Default is to see 64-bit inode numbers */
+static bool enable_ino64 = NFS_64_BIT_INODE_NUMBERS_ENABLED;
+
+static int nfs_update_inode(struct inode *, struct nfs_fattr *);
+
+static struct kmem_cache * nfs_inode_cachep;
+
+static inline unsigned long
+nfs_fattr_to_ino_t(struct nfs_fattr *fattr)
+{
+	return nfs_fileid_to_ino_t(fattr->fileid);
+}
+
+int nfs_wait_bit_killable(struct wait_bit_key *key, int mode)
+{
+	schedule();
+	if (signal_pending_state(mode, current))
+		return -ERESTARTSYS;
+	return 0;
+}
+EXPORT_SYMBOL_GPL(nfs_wait_bit_killable);
+
+/**
+ * nfs_compat_user_ino64 - returns the user-visible inode number
+ * @fileid: 64-bit fileid
+ *
+ * This function returns a 32-bit inode number if the boot parameter
+ * nfs.enable_ino64 is zero.
+ */
+u64 nfs_compat_user_ino64(u64 fileid)
+{
+#ifdef CONFIG_COMPAT
+	compat_ulong_t ino;
+#else	
+	unsigned long ino;
+#endif
+
+	if (enable_ino64)
+		return fileid;
+	ino = fileid;
+	if (sizeof(ino) < sizeof(fileid))
+		ino ^= fileid >> (sizeof(fileid)-sizeof(ino)) * 8;
+	return ino;
+}
+
+int nfs_drop_inode(struct inode *inode)
+{
+	return NFS_STALE(inode) || generic_drop_inode(inode);
+}
+EXPORT_SYMBOL_GPL(nfs_drop_inode);
+
+void nfs_clear_inode(struct inode *inode)
+{
+	/*
+	 * The following should never happen...
+	 */
+	WARN_ON_ONCE(nfs_have_writebacks(inode));
+	WARN_ON_ONCE(!list_empty(&NFS_I(inode)->open_files));
+	nfs_zap_acl_cache(inode);
+	nfs_access_zap_cache(inode);
+	nfs_fscache_clear_inode(inode);
+}
+EXPORT_SYMBOL_GPL(nfs_clear_inode);
+
+void nfs_evict_inode(struct inode *inode)
+{
+	truncate_inode_pages_final(&inode->i_data);
+	clear_inode(inode);
+	nfs_clear_inode(inode);
+}
+
+int nfs_sync_inode(struct inode *inode)
+{
+	inode_dio_wait(inode);
+	return nfs_wb_all(inode);
+}
+EXPORT_SYMBOL_GPL(nfs_sync_inode);
+
+/**
+ * nfs_sync_mapping - helper to flush all mmapped dirty data to disk
+ * @mapping: pointer to struct address_space
+ */
+int nfs_sync_mapping(struct address_space *mapping)
+{
+	int ret = 0;
+
+	if (mapping->nrpages != 0) {
+		unmap_mapping_range(mapping, 0, 0, 0);
+		ret = nfs_wb_all(mapping->host);
+	}
+	return ret;
+}
+
+static int nfs_attribute_timeout(struct inode *inode)
+{
+	struct nfs_inode *nfsi = NFS_I(inode);
+
+	return !time_in_range_open(jiffies, nfsi->read_cache_jiffies, nfsi->read_cache_jiffies + nfsi->attrtimeo);
+}
+
+static bool nfs_check_cache_flags_invalid(struct inode *inode,
+					  unsigned long flags)
+{
+	unsigned long cache_validity = READ_ONCE(NFS_I(inode)->cache_validity);
+
+	return (cache_validity & flags) != 0;
+}
+
+bool nfs_check_cache_invalid(struct inode *inode, unsigned long flags)
+{
+	if (nfs_check_cache_flags_invalid(inode, flags))
+		return true;
+	return nfs_attribute_cache_expired(inode);
+}
+EXPORT_SYMBOL_GPL(nfs_check_cache_invalid);
+
+#ifdef CONFIG_NFS_V4_2
+static bool nfs_has_xattr_cache(const struct nfs_inode *nfsi)
+{
+	return nfsi->xattr_cache != NULL;
+}
+#else
+static bool nfs_has_xattr_cache(const struct nfs_inode *nfsi)
+{
+	return false;
+}
+#endif
+
+void nfs_set_cache_invalid(struct inode *inode, unsigned long flags)
+{
+	struct nfs_inode *nfsi = NFS_I(inode);
+	bool have_delegation = NFS_PROTO(inode)->have_delegation(inode, FMODE_READ);
+
+	if (have_delegation) {
+		if (!(flags & NFS_INO_REVAL_FORCED))
+			flags &= ~(NFS_INO_INVALID_MODE |
+				   NFS_INO_INVALID_OTHER |
+				   NFS_INO_INVALID_XATTR);
+		flags &= ~(NFS_INO_INVALID_CHANGE | NFS_INO_INVALID_SIZE);
+	}
+
+	if (!nfs_has_xattr_cache(nfsi))
+		flags &= ~NFS_INO_INVALID_XATTR;
+	if (flags & NFS_INO_INVALID_DATA)
+		nfs_fscache_invalidate(inode, 0);
+	flags &= ~NFS_INO_REVAL_FORCED;
+
+	nfsi->cache_validity |= flags;
+
+	if (inode->i_mapping->nrpages == 0)
+		nfsi->cache_validity &= ~(NFS_INO_INVALID_DATA |
+					  NFS_INO_DATA_INVAL_DEFER);
+	else if (nfsi->cache_validity & NFS_INO_INVALID_DATA)
+		nfsi->cache_validity &= ~NFS_INO_DATA_INVAL_DEFER;
+	trace_nfs_set_cache_invalid(inode, 0);
+}
+EXPORT_SYMBOL_GPL(nfs_set_cache_invalid);
+
+/*
+ * Invalidate the local caches
+ */
+static void nfs_zap_caches_locked(struct inode *inode)
+{
+	struct nfs_inode *nfsi = NFS_I(inode);
+	int mode = inode->i_mode;
+
+	nfs_inc_stats(inode, NFSIOS_ATTRINVALIDATE);
+
+	nfsi->attrtimeo = NFS_MINATTRTIMEO(inode);
+	nfsi->attrtimeo_timestamp = jiffies;
+
+	if (S_ISREG(mode) || S_ISDIR(mode) || S_ISLNK(mode))
+		nfs_set_cache_invalid(inode, NFS_INO_INVALID_ATTR |
+						     NFS_INO_INVALID_DATA |
+						     NFS_INO_INVALID_ACCESS |
+						     NFS_INO_INVALID_ACL |
+						     NFS_INO_INVALID_XATTR);
+	else
+		nfs_set_cache_invalid(inode, NFS_INO_INVALID_ATTR |
+						     NFS_INO_INVALID_ACCESS |
+						     NFS_INO_INVALID_ACL |
+						     NFS_INO_INVALID_XATTR);
+	nfs_zap_label_cache_locked(nfsi);
+}
+
+void nfs_zap_caches(struct inode *inode)
+{
+	spin_lock(&inode->i_lock);
+	nfs_zap_caches_locked(inode);
+	spin_unlock(&inode->i_lock);
+}
+
+void nfs_zap_mapping(struct inode *inode, struct address_space *mapping)
+{
+	if (mapping->nrpages != 0) {
+		spin_lock(&inode->i_lock);
+		nfs_set_cache_invalid(inode, NFS_INO_INVALID_DATA);
+		spin_unlock(&inode->i_lock);
+	}
+}
+
+void nfs_zap_acl_cache(struct inode *inode)
+{
+	void (*clear_acl_cache)(struct inode *);
+
+	clear_acl_cache = NFS_PROTO(inode)->clear_acl_cache;
+	if (clear_acl_cache != NULL)
+		clear_acl_cache(inode);
+	spin_lock(&inode->i_lock);
+	NFS_I(inode)->cache_validity &= ~NFS_INO_INVALID_ACL;
+	spin_unlock(&inode->i_lock);
+}
+EXPORT_SYMBOL_GPL(nfs_zap_acl_cache);
+
+void nfs_invalidate_atime(struct inode *inode)
+{
+	spin_lock(&inode->i_lock);
+	nfs_set_cache_invalid(inode, NFS_INO_INVALID_ATIME);
+	spin_unlock(&inode->i_lock);
+}
+EXPORT_SYMBOL_GPL(nfs_invalidate_atime);
+
+/*
+ * Invalidate, but do not unhash, the inode.
+ * NB: must be called with inode->i_lock held!
+ */
+static void nfs_set_inode_stale_locked(struct inode *inode)
+{
+	set_bit(NFS_INO_STALE, &NFS_I(inode)->flags);
+	nfs_zap_caches_locked(inode);
+	trace_nfs_set_inode_stale(inode);
+}
+
+void nfs_set_inode_stale(struct inode *inode)
+{
+	spin_lock(&inode->i_lock);
+	nfs_set_inode_stale_locked(inode);
+	spin_unlock(&inode->i_lock);
+}
+
+struct nfs_find_desc {
+	struct nfs_fh		*fh;
+	struct nfs_fattr	*fattr;
+};
+
+/*
+ * In NFSv3 we can have 64bit inode numbers. In order to support
+ * this, and re-exported directories (also seen in NFSv2)
+ * we are forced to allow 2 different inodes to have the same
+ * i_ino.
+ */
+static int
+nfs_find_actor(struct inode *inode, void *opaque)
+{
+	struct nfs_find_desc	*desc = opaque;
+	struct nfs_fh		*fh = desc->fh;
+	struct nfs_fattr	*fattr = desc->fattr;
+
+	if (NFS_FILEID(inode) != fattr->fileid)
+		return 0;
+	if (inode_wrong_type(inode, fattr->mode))
+		return 0;
+	if (nfs_compare_fh(NFS_FH(inode), fh))
+		return 0;
+	if (is_bad_inode(inode) || NFS_STALE(inode))
+		return 0;
+	return 1;
+}
+
+static int
+nfs_init_locked(struct inode *inode, void *opaque)
+{
+	struct nfs_find_desc	*desc = opaque;
+	struct nfs_fattr	*fattr = desc->fattr;
+
+	set_nfs_fileid(inode, fattr->fileid);
+	inode->i_mode = fattr->mode;
+	nfs_copy_fh(NFS_FH(inode), desc->fh);
+	return 0;
+}
+
+#ifdef CONFIG_NFS_V4_SECURITY_LABEL
+static void nfs_clear_label_invalid(struct inode *inode)
+{
+	spin_lock(&inode->i_lock);
+	NFS_I(inode)->cache_validity &= ~NFS_INO_INVALID_LABEL;
+	spin_unlock(&inode->i_lock);
+}
+
+void nfs_setsecurity(struct inode *inode, struct nfs_fattr *fattr)
+{
+	int error;
+
+	if (fattr->label == NULL)
+		return;
+
+	if ((fattr->valid & NFS_ATTR_FATTR_V4_SECURITY_LABEL) && inode->i_security) {
+		error = security_inode_notifysecctx(inode, fattr->label->label,
+				fattr->label->len);
+		if (error)
+			printk(KERN_ERR "%s() %s %d "
+					"security_inode_notifysecctx() %d\n",
+					__func__,
+					(char *)fattr->label->label,
+					fattr->label->len, error);
+		nfs_clear_label_invalid(inode);
+	}
+}
+
+struct nfs4_label *nfs4_label_alloc(struct nfs_server *server, gfp_t flags)
+{
+	struct nfs4_label *label;
+
+	if (!(server->caps & NFS_CAP_SECURITY_LABEL))
+		return NULL;
+
+	label = kzalloc(sizeof(struct nfs4_label), flags);
+	if (label == NULL)
+		return ERR_PTR(-ENOMEM);
+
+	label->label = kzalloc(NFS4_MAXLABELLEN, flags);
+	if (label->label == NULL) {
+		kfree(label);
+		return ERR_PTR(-ENOMEM);
+	}
+	label->len = NFS4_MAXLABELLEN;
+
+	return label;
+}
+EXPORT_SYMBOL_GPL(nfs4_label_alloc);
+#else
+void nfs_setsecurity(struct inode *inode, struct nfs_fattr *fattr)
+{
+}
+#endif
+EXPORT_SYMBOL_GPL(nfs_setsecurity);
+
+/* Search for inode identified by fh, fileid and i_mode in inode cache. */
+struct inode *
+nfs_ilookup(struct super_block *sb, struct nfs_fattr *fattr, struct nfs_fh *fh)
+{
+	struct nfs_find_desc desc = {
+		.fh	= fh,
+		.fattr	= fattr,
+	};
+	struct inode *inode;
+	unsigned long hash;
+
+	if (!(fattr->valid & NFS_ATTR_FATTR_FILEID) ||
+	    !(fattr->valid & NFS_ATTR_FATTR_TYPE))
+		return NULL;
+
+	hash = nfs_fattr_to_ino_t(fattr);
+	inode = ilookup5(sb, hash, nfs_find_actor, &desc);
+
+	dprintk("%s: returning %p\n", __func__, inode);
+	return inode;
+}
+
+static void nfs_inode_init_regular(struct nfs_inode *nfsi)
+{
+	atomic_long_set(&nfsi->nrequests, 0);
+	atomic_long_set(&nfsi->redirtied_pages, 0);
+	INIT_LIST_HEAD(&nfsi->commit_info.list);
+	atomic_long_set(&nfsi->commit_info.ncommit, 0);
+	atomic_set(&nfsi->commit_info.rpcs_out, 0);
+	mutex_init(&nfsi->commit_mutex);
+}
+
+static void nfs_inode_init_dir(struct nfs_inode *nfsi)
+{
+	nfsi->cache_change_attribute = 0;
+	memset(nfsi->cookieverf, 0, sizeof(nfsi->cookieverf));
+	init_rwsem(&nfsi->rmdir_sem);
+}
+
+/*
+ * This is our front-end to iget that looks up inodes by file handle
+ * instead of inode number.
+ */
+struct inode *
+nfs_fhget(struct super_block *sb, struct nfs_fh *fh, struct nfs_fattr *fattr)
+{
+	struct nfs_find_desc desc = {
+		.fh	= fh,
+		.fattr	= fattr
+	};
+	struct inode *inode = ERR_PTR(-ENOENT);
+	u64 fattr_supported = NFS_SB(sb)->fattr_valid;
+	unsigned long hash;
+
+	nfs_attr_check_mountpoint(sb, fattr);
+
+	if (nfs_attr_use_mounted_on_fileid(fattr))
+		fattr->fileid = fattr->mounted_on_fileid;
+	else if ((fattr->valid & NFS_ATTR_FATTR_FILEID) == 0)
+		goto out_no_inode;
+	if ((fattr->valid & NFS_ATTR_FATTR_TYPE) == 0)
+		goto out_no_inode;
+
+	hash = nfs_fattr_to_ino_t(fattr);
+
+	inode = iget5_locked(sb, hash, nfs_find_actor, nfs_init_locked, &desc);
+	if (inode == NULL) {
+		inode = ERR_PTR(-ENOMEM);
+		goto out_no_inode;
+	}
+
+	if (inode->i_state & I_NEW) {
+		struct nfs_inode *nfsi = NFS_I(inode);
+		unsigned long now = jiffies;
+
+		/* We set i_ino for the few things that still rely on it,
+		 * such as stat(2) */
+		inode->i_ino = hash;
+
+		/* We can't support update_atime(), since the server will reset it */
+		inode->i_flags |= S_NOATIME|S_NOCMTIME;
+		inode->i_mode = fattr->mode;
+		nfsi->cache_validity = 0;
+		if ((fattr->valid & NFS_ATTR_FATTR_MODE) == 0
+				&& (fattr_supported & NFS_ATTR_FATTR_MODE))
+			nfs_set_cache_invalid(inode, NFS_INO_INVALID_MODE);
+		/* Why so? Because we want revalidate for devices/FIFOs, and
+		 * that's precisely what we have in nfs_file_inode_operations.
+		 */
+		inode->i_op = NFS_SB(sb)->nfs_client->rpc_ops->file_inode_ops;
+		if (S_ISREG(inode->i_mode)) {
+			inode->i_fop = NFS_SB(sb)->nfs_client->rpc_ops->file_ops;
+			inode->i_data.a_ops = &nfs_file_aops;
+			nfs_inode_init_regular(nfsi);
+		} else if (S_ISDIR(inode->i_mode)) {
+			inode->i_op = NFS_SB(sb)->nfs_client->rpc_ops->dir_inode_ops;
+			inode->i_fop = &nfs_dir_operations;
+			inode->i_data.a_ops = &nfs_dir_aops;
+			nfs_inode_init_dir(nfsi);
+			/* Deal with crossing mountpoints */
+			if (fattr->valid & NFS_ATTR_FATTR_MOUNTPOINT ||
+					fattr->valid & NFS_ATTR_FATTR_V4_REFERRAL) {
+				if (fattr->valid & NFS_ATTR_FATTR_V4_REFERRAL)
+					inode->i_op = &nfs_referral_inode_operations;
+				else
+					inode->i_op = &nfs_mountpoint_inode_operations;
+				inode->i_fop = NULL;
+				inode->i_flags |= S_AUTOMOUNT;
+			}
+		} else if (S_ISLNK(inode->i_mode)) {
+			inode->i_op = &nfs_symlink_inode_operations;
+			inode_nohighmem(inode);
+		} else
+			init_special_inode(inode, inode->i_mode, fattr->rdev);
+
+		memset(&inode->i_atime, 0, sizeof(inode->i_atime));
+		memset(&inode->i_mtime, 0, sizeof(inode->i_mtime));
+		memset(&inode->i_ctime, 0, sizeof(inode->i_ctime));
+		inode_set_iversion_raw(inode, 0);
+		inode->i_size = 0;
+		clear_nlink(inode);
+		inode->i_uid = make_kuid(&init_user_ns, -2);
+		inode->i_gid = make_kgid(&init_user_ns, -2);
+		inode->i_blocks = 0;
+		nfsi->write_io = 0;
+		nfsi->read_io = 0;
+
+		nfsi->read_cache_jiffies = fattr->time_start;
+		nfsi->attr_gencount = fattr->gencount;
+		if (fattr->valid & NFS_ATTR_FATTR_ATIME)
+			inode->i_atime = fattr->atime;
+		else if (fattr_supported & NFS_ATTR_FATTR_ATIME)
+			nfs_set_cache_invalid(inode, NFS_INO_INVALID_ATIME);
+		if (fattr->valid & NFS_ATTR_FATTR_MTIME)
+			inode->i_mtime = fattr->mtime;
+		else if (fattr_supported & NFS_ATTR_FATTR_MTIME)
+			nfs_set_cache_invalid(inode, NFS_INO_INVALID_MTIME);
+		if (fattr->valid & NFS_ATTR_FATTR_CTIME)
+			inode->i_ctime = fattr->ctime;
+		else if (fattr_supported & NFS_ATTR_FATTR_CTIME)
+			nfs_set_cache_invalid(inode, NFS_INO_INVALID_CTIME);
+		if (fattr->valid & NFS_ATTR_FATTR_CHANGE)
+			inode_set_iversion_raw(inode, fattr->change_attr);
+		else
+			nfs_set_cache_invalid(inode, NFS_INO_INVALID_CHANGE);
+		if (fattr->valid & NFS_ATTR_FATTR_SIZE)
+			inode->i_size = nfs_size_to_loff_t(fattr->size);
+		else
+			nfs_set_cache_invalid(inode, NFS_INO_INVALID_SIZE);
+		if (fattr->valid & NFS_ATTR_FATTR_NLINK)
+			set_nlink(inode, fattr->nlink);
+		else if (fattr_supported & NFS_ATTR_FATTR_NLINK)
+			nfs_set_cache_invalid(inode, NFS_INO_INVALID_NLINK);
+		if (fattr->valid & NFS_ATTR_FATTR_OWNER)
+			inode->i_uid = fattr->uid;
+		else if (fattr_supported & NFS_ATTR_FATTR_OWNER)
+			nfs_set_cache_invalid(inode, NFS_INO_INVALID_OTHER);
+		if (fattr->valid & NFS_ATTR_FATTR_GROUP)
+			inode->i_gid = fattr->gid;
+		else if (fattr_supported & NFS_ATTR_FATTR_GROUP)
+			nfs_set_cache_invalid(inode, NFS_INO_INVALID_OTHER);
+		if (fattr->valid & NFS_ATTR_FATTR_BLOCKS_USED)
+			inode->i_blocks = fattr->du.nfs2.blocks;
+		else if (fattr_supported & NFS_ATTR_FATTR_BLOCKS_USED &&
+			 fattr->size != 0)
+			nfs_set_cache_invalid(inode, NFS_INO_INVALID_BLOCKS);
+		if (fattr->valid & NFS_ATTR_FATTR_SPACE_USED) {
+			/*
+			 * report the blocks in 512byte units
+			 */
+			inode->i_blocks = nfs_calc_block_size(fattr->du.nfs3.used);
+		} else if (fattr_supported & NFS_ATTR_FATTR_SPACE_USED &&
+			   fattr->size != 0)
+			nfs_set_cache_invalid(inode, NFS_INO_INVALID_BLOCKS);
+
+		nfs_setsecurity(inode, fattr);
+
+		nfsi->attrtimeo = NFS_MINATTRTIMEO(inode);
+		nfsi->attrtimeo_timestamp = now;
+		nfsi->access_cache = RB_ROOT;
+
+		nfs_fscache_init_inode(inode);
+
+		unlock_new_inode(inode);
+	} else {
+		int err = nfs_refresh_inode(inode, fattr);
+		if (err < 0) {
+			iput(inode);
+			inode = ERR_PTR(err);
+			goto out_no_inode;
+		}
+	}
+	dprintk("NFS: nfs_fhget(%s/%Lu fh_crc=0x%08x ct=%d)\n",
+		inode->i_sb->s_id,
+		(unsigned long long)NFS_FILEID(inode),
+		nfs_display_fhandle_hash(fh),
+		atomic_read(&inode->i_count));
+
+out:
+	return inode;
+
+out_no_inode:
+	dprintk("nfs_fhget: iget failed with error %ld\n", PTR_ERR(inode));
+	goto out;
+}
+EXPORT_SYMBOL_GPL(nfs_fhget);
+
+#define NFS_VALID_ATTRS (ATTR_MODE|ATTR_UID|ATTR_GID|ATTR_SIZE|ATTR_ATIME|ATTR_ATIME_SET|ATTR_MTIME|ATTR_MTIME_SET|ATTR_FILE|ATTR_OPEN)
+
+int
+nfs_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
+	    struct iattr *attr)
+{
+	struct inode *inode = d_inode(dentry);
+	struct nfs_fattr *fattr;
+	int error = 0;
+
+	nfs_inc_stats(inode, NFSIOS_VFSSETATTR);
+
+	/* skip mode change if it's just for clearing setuid/setgid */
+	if (attr->ia_valid & (ATTR_KILL_SUID | ATTR_KILL_SGID))
+		attr->ia_valid &= ~ATTR_MODE;
+
+	if (attr->ia_valid & ATTR_SIZE) {
+		BUG_ON(!S_ISREG(inode->i_mode));
+
+		error = inode_newsize_ok(inode, attr->ia_size);
+		if (error)
+			return error;
+
+		if (attr->ia_size == i_size_read(inode))
+			attr->ia_valid &= ~ATTR_SIZE;
+	}
+
+	/* Optimization: if the end result is no change, don't RPC */
+	if (((attr->ia_valid & NFS_VALID_ATTRS) & ~(ATTR_FILE|ATTR_OPEN)) == 0)
+		return 0;
+
+	trace_nfs_setattr_enter(inode);
+
+	/* Write all dirty data */
+	if (S_ISREG(inode->i_mode))
+		nfs_sync_inode(inode);
+
+	fattr = nfs_alloc_fattr_with_label(NFS_SERVER(inode));
+	if (fattr == NULL) {
+		error = -ENOMEM;
+		goto out;
+	}
+
+	error = NFS_PROTO(inode)->setattr(dentry, fattr, attr);
+	if (error == 0)
+		error = nfs_refresh_inode(inode, fattr);
+	nfs_free_fattr(fattr);
+out:
+	trace_nfs_setattr_exit(inode, error);
+	return error;
+}
+EXPORT_SYMBOL_GPL(nfs_setattr);
+
+/**
+ * nfs_vmtruncate - unmap mappings "freed" by truncate() syscall
+ * @inode: inode of the file used
+ * @offset: file offset to start truncating
+ *
+ * This is a copy of the common vmtruncate, but with the locking
+ * corrected to take into account the fact that NFS requires
+ * inode->i_size to be updated under the inode->i_lock.
+ * Note: must be called with inode->i_lock held!
+ */
+static int nfs_vmtruncate(struct inode * inode, loff_t offset)
+{
+	int err;
+
+	err = inode_newsize_ok(inode, offset);
+	if (err)
+		goto out;
+
+	trace_nfs_size_truncate(inode, offset);
+	i_size_write(inode, offset);
+	/* Optimisation */
+	if (offset == 0)
+		NFS_I(inode)->cache_validity &= ~(NFS_INO_INVALID_DATA |
+				NFS_INO_DATA_INVAL_DEFER);
+	NFS_I(inode)->cache_validity &= ~NFS_INO_INVALID_SIZE;
+
+	spin_unlock(&inode->i_lock);
+	truncate_pagecache(inode, offset);
+	spin_lock(&inode->i_lock);
+out:
+	return err;
+}
+
+/**
+ * nfs_setattr_update_inode - Update inode metadata after a setattr call.
+ * @inode: pointer to struct inode
+ * @attr: pointer to struct iattr
+ * @fattr: pointer to struct nfs_fattr
+ *
+ * Note: we do this in the *proc.c in order to ensure that
+ *       it works for things like exclusive creates too.
+ */
+void nfs_setattr_update_inode(struct inode *inode, struct iattr *attr,
+		struct nfs_fattr *fattr)
+{
+	/* Barrier: bump the attribute generation count. */
+	nfs_fattr_set_barrier(fattr);
+
+	spin_lock(&inode->i_lock);
+	NFS_I(inode)->attr_gencount = fattr->gencount;
+	if ((attr->ia_valid & ATTR_SIZE) != 0) {
+		nfs_set_cache_invalid(inode, NFS_INO_INVALID_MTIME |
+						     NFS_INO_INVALID_BLOCKS);
+		nfs_inc_stats(inode, NFSIOS_SETATTRTRUNC);
+		nfs_vmtruncate(inode, attr->ia_size);
+	}
+	if ((attr->ia_valid & (ATTR_MODE|ATTR_UID|ATTR_GID)) != 0) {
+		NFS_I(inode)->cache_validity &= ~NFS_INO_INVALID_CTIME;
+		if ((attr->ia_valid & ATTR_KILL_SUID) != 0 &&
+		    inode->i_mode & S_ISUID)
+			inode->i_mode &= ~S_ISUID;
+		if (setattr_should_drop_sgid(&init_user_ns, inode))
+			inode->i_mode &= ~S_ISGID;
+		if ((attr->ia_valid & ATTR_MODE) != 0) {
+			int mode = attr->ia_mode & S_IALLUGO;
+			mode |= inode->i_mode & ~S_IALLUGO;
+			inode->i_mode = mode;
+		}
+		if ((attr->ia_valid & ATTR_UID) != 0)
+			inode->i_uid = attr->ia_uid;
+		if ((attr->ia_valid & ATTR_GID) != 0)
+			inode->i_gid = attr->ia_gid;
+		if (fattr->valid & NFS_ATTR_FATTR_CTIME)
+			inode->i_ctime = fattr->ctime;
+		else
+			nfs_set_cache_invalid(inode, NFS_INO_INVALID_CHANGE
+					| NFS_INO_INVALID_CTIME);
+		nfs_set_cache_invalid(inode, NFS_INO_INVALID_ACCESS
+				| NFS_INO_INVALID_ACL);
+	}
+	if (attr->ia_valid & (ATTR_ATIME_SET|ATTR_ATIME)) {
+		NFS_I(inode)->cache_validity &= ~(NFS_INO_INVALID_ATIME
+				| NFS_INO_INVALID_CTIME);
+		if (fattr->valid & NFS_ATTR_FATTR_ATIME)
+			inode->i_atime = fattr->atime;
+		else if (attr->ia_valid & ATTR_ATIME_SET)
+			inode->i_atime = attr->ia_atime;
+		else
+			nfs_set_cache_invalid(inode, NFS_INO_INVALID_ATIME);
+
+		if (fattr->valid & NFS_ATTR_FATTR_CTIME)
+			inode->i_ctime = fattr->ctime;
+		else
+			nfs_set_cache_invalid(inode, NFS_INO_INVALID_CHANGE
+					| NFS_INO_INVALID_CTIME);
+	}
+	if (attr->ia_valid & (ATTR_MTIME_SET|ATTR_MTIME)) {
+		NFS_I(inode)->cache_validity &= ~(NFS_INO_INVALID_MTIME
+				| NFS_INO_INVALID_CTIME);
+		if (fattr->valid & NFS_ATTR_FATTR_MTIME)
+			inode->i_mtime = fattr->mtime;
+		else if (attr->ia_valid & ATTR_MTIME_SET)
+			inode->i_mtime = attr->ia_mtime;
+		else
+			nfs_set_cache_invalid(inode, NFS_INO_INVALID_MTIME);
+
+		if (fattr->valid & NFS_ATTR_FATTR_CTIME)
+			inode->i_ctime = fattr->ctime;
+		else
+			nfs_set_cache_invalid(inode, NFS_INO_INVALID_CHANGE
+					| NFS_INO_INVALID_CTIME);
+	}
+	if (fattr->valid)
+		nfs_update_inode(inode, fattr);
+	spin_unlock(&inode->i_lock);
+}
+EXPORT_SYMBOL_GPL(nfs_setattr_update_inode);
+
+/*
+ * Don't request help from readdirplus if the file is being written to,
+ * or if attribute caching is turned off
+ */
+static bool nfs_getattr_readdirplus_enable(const struct inode *inode)
+{
+	return nfs_server_capable(inode, NFS_CAP_READDIRPLUS) &&
+	       !nfs_have_writebacks(inode) && NFS_MAXATTRTIMEO(inode) > 5 * HZ;
+}
+
+static void nfs_readdirplus_parent_cache_miss(struct dentry *dentry)
+{
+	if (!IS_ROOT(dentry)) {
+		struct dentry *parent = dget_parent(dentry);
+		nfs_readdir_record_entry_cache_miss(d_inode(parent));
+		dput(parent);
+	}
+}
+
+static void nfs_readdirplus_parent_cache_hit(struct dentry *dentry)
+{
+	if (!IS_ROOT(dentry)) {
+		struct dentry *parent = dget_parent(dentry);
+		nfs_readdir_record_entry_cache_hit(d_inode(parent));
+		dput(parent);
+	}
+}
+
+static u32 nfs_get_valid_attrmask(struct inode *inode)
+{
+	unsigned long cache_validity = READ_ONCE(NFS_I(inode)->cache_validity);
+	u32 reply_mask = STATX_INO | STATX_TYPE;
+
+	if (!(cache_validity & NFS_INO_INVALID_ATIME))
+		reply_mask |= STATX_ATIME;
+	if (!(cache_validity & NFS_INO_INVALID_CTIME))
+		reply_mask |= STATX_CTIME;
+	if (!(cache_validity & NFS_INO_INVALID_MTIME))
+		reply_mask |= STATX_MTIME;
+	if (!(cache_validity & NFS_INO_INVALID_SIZE))
+		reply_mask |= STATX_SIZE;
+	if (!(cache_validity & NFS_INO_INVALID_NLINK))
+		reply_mask |= STATX_NLINK;
+	if (!(cache_validity & NFS_INO_INVALID_MODE))
+		reply_mask |= STATX_MODE;
+	if (!(cache_validity & NFS_INO_INVALID_OTHER))
+		reply_mask |= STATX_UID | STATX_GID;
+	if (!(cache_validity & NFS_INO_INVALID_BLOCKS))
+		reply_mask |= STATX_BLOCKS;
+	return reply_mask;
+}
+
+int nfs_getattr(struct user_namespace *mnt_userns, const struct path *path,
+		struct kstat *stat, u32 request_mask, unsigned int query_flags)
+{
+	struct inode *inode = d_inode(path->dentry);
+	struct nfs_server *server = NFS_SERVER(inode);
+	unsigned long cache_validity;
+	int err = 0;
+	bool force_sync = query_flags & AT_STATX_FORCE_SYNC;
+	bool do_update = false;
+	bool readdirplus_enabled = nfs_getattr_readdirplus_enable(inode);
+
+	trace_nfs_getattr_enter(inode);
+
+	request_mask &= STATX_TYPE | STATX_MODE | STATX_NLINK | STATX_UID |
+			STATX_GID | STATX_ATIME | STATX_MTIME | STATX_CTIME |
+			STATX_INO | STATX_SIZE | STATX_BLOCKS;
+
+	if ((query_flags & AT_STATX_DONT_SYNC) && !force_sync) {
+		if (readdirplus_enabled)
+			nfs_readdirplus_parent_cache_hit(path->dentry);
+		goto out_no_revalidate;
+	}
+
+	/* Flush out writes to the server in order to update c/mtime.  */
+	if ((request_mask & (STATX_CTIME | STATX_MTIME)) &&
+	    S_ISREG(inode->i_mode))
+		filemap_write_and_wait(inode->i_mapping);
+
+	/*
+	 * We may force a getattr if the user cares about atime.
+	 *
+	 * Note that we only have to check the vfsmount flags here:
+	 *  - NFS always sets S_NOATIME by so checking it would give a
+	 *    bogus result
+	 *  - NFS never sets SB_NOATIME or SB_NODIRATIME so there is
+	 *    no point in checking those.
+	 */
+	if ((path->mnt->mnt_flags & MNT_NOATIME) ||
+	    ((path->mnt->mnt_flags & MNT_NODIRATIME) && S_ISDIR(inode->i_mode)))
+		request_mask &= ~STATX_ATIME;
+
+	/* Is the user requesting attributes that might need revalidation? */
+	if (!(request_mask & (STATX_MODE|STATX_NLINK|STATX_ATIME|STATX_CTIME|
+					STATX_MTIME|STATX_UID|STATX_GID|
+					STATX_SIZE|STATX_BLOCKS)))
+		goto out_no_revalidate;
+
+	/* Check whether the cached attributes are stale */
+	do_update |= force_sync || nfs_attribute_cache_expired(inode);
+	cache_validity = READ_ONCE(NFS_I(inode)->cache_validity);
+	do_update |= cache_validity & NFS_INO_INVALID_CHANGE;
+	if (request_mask & STATX_ATIME)
+		do_update |= cache_validity & NFS_INO_INVALID_ATIME;
+	if (request_mask & STATX_CTIME)
+		do_update |= cache_validity & NFS_INO_INVALID_CTIME;
+	if (request_mask & STATX_MTIME)
+		do_update |= cache_validity & NFS_INO_INVALID_MTIME;
+	if (request_mask & STATX_SIZE)
+		do_update |= cache_validity & NFS_INO_INVALID_SIZE;
+	if (request_mask & STATX_NLINK)
+		do_update |= cache_validity & NFS_INO_INVALID_NLINK;
+	if (request_mask & STATX_MODE)
+		do_update |= cache_validity & NFS_INO_INVALID_MODE;
+	if (request_mask & (STATX_UID | STATX_GID))
+		do_update |= cache_validity & NFS_INO_INVALID_OTHER;
+	if (request_mask & STATX_BLOCKS)
+		do_update |= cache_validity & NFS_INO_INVALID_BLOCKS;
+
+	if (do_update) {
+		if (readdirplus_enabled)
+			nfs_readdirplus_parent_cache_miss(path->dentry);
+		err = __nfs_revalidate_inode(server, inode);
+		if (err)
+			goto out;
+	} else if (readdirplus_enabled)
+		nfs_readdirplus_parent_cache_hit(path->dentry);
+out_no_revalidate:
+	/* Only return attributes that were revalidated. */
+	stat->result_mask = nfs_get_valid_attrmask(inode) | request_mask;
+
+	generic_fillattr(&init_user_ns, inode, stat);
+	stat->ino = nfs_compat_user_ino64(NFS_FILEID(inode));
+	if (S_ISDIR(inode->i_mode))
+		stat->blksize = NFS_SERVER(inode)->dtsize;
+out:
+	trace_nfs_getattr_exit(inode, err);
+	return err;
+}
+EXPORT_SYMBOL_GPL(nfs_getattr);
+
+static void nfs_init_lock_context(struct nfs_lock_context *l_ctx)
+{
+	refcount_set(&l_ctx->count, 1);
+	l_ctx->lockowner = current->files;
+	INIT_LIST_HEAD(&l_ctx->list);
+	atomic_set(&l_ctx->io_count, 0);
+}
+
+static struct nfs_lock_context *__nfs_find_lock_context(struct nfs_open_context *ctx)
+{
+	struct nfs_lock_context *pos;
+
+	list_for_each_entry_rcu(pos, &ctx->lock_context.list, list) {
+		if (pos->lockowner != current->files)
+			continue;
+		if (refcount_inc_not_zero(&pos->count))
+			return pos;
+	}
+	return NULL;
+}
+
+struct nfs_lock_context *nfs_get_lock_context(struct nfs_open_context *ctx)
+{
+	struct nfs_lock_context *res, *new = NULL;
+	struct inode *inode = d_inode(ctx->dentry);
+
+	rcu_read_lock();
+	res = __nfs_find_lock_context(ctx);
+	rcu_read_unlock();
+	if (res == NULL) {
+		new = kmalloc(sizeof(*new), GFP_KERNEL_ACCOUNT);
+		if (new == NULL)
+			return ERR_PTR(-ENOMEM);
+		nfs_init_lock_context(new);
+		spin_lock(&inode->i_lock);
+		res = __nfs_find_lock_context(ctx);
+		if (res == NULL) {
+			new->open_context = get_nfs_open_context(ctx);
+			if (new->open_context) {
+				list_add_tail_rcu(&new->list,
+						&ctx->lock_context.list);
+				res = new;
+				new = NULL;
+			} else
+				res = ERR_PTR(-EBADF);
+		}
+		spin_unlock(&inode->i_lock);
+		kfree(new);
+	}
+	return res;
+}
+EXPORT_SYMBOL_GPL(nfs_get_lock_context);
+
+void nfs_put_lock_context(struct nfs_lock_context *l_ctx)
+{
+	struct nfs_open_context *ctx = l_ctx->open_context;
+	struct inode *inode = d_inode(ctx->dentry);
+
+	if (!refcount_dec_and_lock(&l_ctx->count, &inode->i_lock))
+		return;
+	list_del_rcu(&l_ctx->list);
+	spin_unlock(&inode->i_lock);
+	put_nfs_open_context(ctx);
+	kfree_rcu(l_ctx, rcu_head);
+}
+EXPORT_SYMBOL_GPL(nfs_put_lock_context);
+
+/**
+ * nfs_close_context - Common close_context() routine NFSv2/v3
+ * @ctx: pointer to context
+ * @is_sync: is this a synchronous close
+ *
+ * Ensure that the attributes are up to date if we're mounted
+ * with close-to-open semantics and we have cached data that will
+ * need to be revalidated on open.
+ */
+void nfs_close_context(struct nfs_open_context *ctx, int is_sync)
+{
+	struct nfs_inode *nfsi;
+	struct inode *inode;
+
+	if (!(ctx->mode & FMODE_WRITE))
+		return;
+	if (!is_sync)
+		return;
+	inode = d_inode(ctx->dentry);
+	if (NFS_PROTO(inode)->have_delegation(inode, FMODE_READ))
+		return;
+	nfsi = NFS_I(inode);
+	if (inode->i_mapping->nrpages == 0)
+		return;
+	if (nfsi->cache_validity & NFS_INO_INVALID_DATA)
+		return;
+	if (!list_empty(&nfsi->open_files))
+		return;
+	if (NFS_SERVER(inode)->flags & NFS_MOUNT_NOCTO)
+		return;
+	nfs_revalidate_inode(inode,
+			     NFS_INO_INVALID_CHANGE | NFS_INO_INVALID_SIZE);
+}
+EXPORT_SYMBOL_GPL(nfs_close_context);
+
+struct nfs_open_context *alloc_nfs_open_context(struct dentry *dentry,
+						fmode_t f_mode,
+						struct file *filp)
+{
+	struct nfs_open_context *ctx;
+
+	ctx = kmalloc(sizeof(*ctx), GFP_KERNEL_ACCOUNT);
+	if (!ctx)
+		return ERR_PTR(-ENOMEM);
+	nfs_sb_active(dentry->d_sb);
+	ctx->dentry = dget(dentry);
+	if (filp)
+		ctx->cred = get_cred(filp->f_cred);
+	else
+		ctx->cred = get_current_cred();
+	rcu_assign_pointer(ctx->ll_cred, NULL);
+	ctx->state = NULL;
+	ctx->mode = f_mode;
+	ctx->flags = 0;
+	ctx->error = 0;
+	ctx->flock_owner = (fl_owner_t)filp;
+	nfs_init_lock_context(&ctx->lock_context);
+	ctx->lock_context.open_context = ctx;
+	INIT_LIST_HEAD(&ctx->list);
+	ctx->mdsthreshold = NULL;
+	return ctx;
+}
+EXPORT_SYMBOL_GPL(alloc_nfs_open_context);
+
+struct nfs_open_context *get_nfs_open_context(struct nfs_open_context *ctx)
+{
+	if (ctx != NULL && refcount_inc_not_zero(&ctx->lock_context.count))
+		return ctx;
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(get_nfs_open_context);
+
+static void __put_nfs_open_context(struct nfs_open_context *ctx, int is_sync)
+{
+	struct inode *inode = d_inode(ctx->dentry);
+	struct super_block *sb = ctx->dentry->d_sb;
+
+	if (!refcount_dec_and_test(&ctx->lock_context.count))
+		return;
+	if (!list_empty(&ctx->list)) {
+		spin_lock(&inode->i_lock);
+		list_del_rcu(&ctx->list);
+		spin_unlock(&inode->i_lock);
+	}
+	if (inode != NULL)
+		NFS_PROTO(inode)->close_context(ctx, is_sync);
+	put_cred(ctx->cred);
+	dput(ctx->dentry);
+	nfs_sb_deactive(sb);
+	put_rpccred(rcu_dereference_protected(ctx->ll_cred, 1));
+	kfree(ctx->mdsthreshold);
+	kfree_rcu(ctx, rcu_head);
+}
+
+void put_nfs_open_context(struct nfs_open_context *ctx)
+{
+	__put_nfs_open_context(ctx, 0);
+}
+EXPORT_SYMBOL_GPL(put_nfs_open_context);
+
+static void put_nfs_open_context_sync(struct nfs_open_context *ctx)
+{
+	__put_nfs_open_context(ctx, 1);
+}
+
+/*
+ * Ensure that mmap has a recent RPC credential for use when writing out
+ * shared pages
+ */
+void nfs_inode_attach_open_context(struct nfs_open_context *ctx)
+{
+	struct inode *inode = d_inode(ctx->dentry);
+	struct nfs_inode *nfsi = NFS_I(inode);
+
+	spin_lock(&inode->i_lock);
+	if (list_empty(&nfsi->open_files) &&
+	    (nfsi->cache_validity & NFS_INO_DATA_INVAL_DEFER))
+		nfs_set_cache_invalid(inode, NFS_INO_INVALID_DATA |
+						     NFS_INO_REVAL_FORCED);
+	list_add_tail_rcu(&ctx->list, &nfsi->open_files);
+	spin_unlock(&inode->i_lock);
+}
+EXPORT_SYMBOL_GPL(nfs_inode_attach_open_context);
+
+void nfs_file_set_open_context(struct file *filp, struct nfs_open_context *ctx)
+{
+	filp->private_data = get_nfs_open_context(ctx);
+	set_bit(NFS_CONTEXT_FILE_OPEN, &ctx->flags);
+	if (list_empty(&ctx->list))
+		nfs_inode_attach_open_context(ctx);
+}
+EXPORT_SYMBOL_GPL(nfs_file_set_open_context);
+
+/*
+ * Given an inode, search for an open context with the desired characteristics
+ */
+struct nfs_open_context *nfs_find_open_context(struct inode *inode, const struct cred *cred, fmode_t mode)
+{
+	struct nfs_inode *nfsi = NFS_I(inode);
+	struct nfs_open_context *pos, *ctx = NULL;
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(pos, &nfsi->open_files, list) {
+		if (cred != NULL && cred_fscmp(pos->cred, cred) != 0)
+			continue;
+		if ((pos->mode & (FMODE_READ|FMODE_WRITE)) != mode)
+			continue;
+		if (!test_bit(NFS_CONTEXT_FILE_OPEN, &pos->flags))
+			continue;
+		ctx = get_nfs_open_context(pos);
+		if (ctx)
+			break;
+	}
+	rcu_read_unlock();
+	return ctx;
+}
+
+void nfs_file_clear_open_context(struct file *filp)
+{
+	struct nfs_open_context *ctx = nfs_file_open_context(filp);
+
+	if (ctx) {
+		struct inode *inode = d_inode(ctx->dentry);
+
+		clear_bit(NFS_CONTEXT_FILE_OPEN, &ctx->flags);
+		/*
+		 * We fatal error on write before. Try to writeback
+		 * every page again.
+		 */
+		if (ctx->error < 0)
+			invalidate_inode_pages2(inode->i_mapping);
+		filp->private_data = NULL;
+		put_nfs_open_context_sync(ctx);
+	}
+}
+
+/*
+ * These allocate and release file read/write context information.
+ */
+int nfs_open(struct inode *inode, struct file *filp)
+{
+	struct nfs_open_context *ctx;
+
+	ctx = alloc_nfs_open_context(file_dentry(filp), filp->f_mode, filp);
+	if (IS_ERR(ctx))
+		return PTR_ERR(ctx);
+	nfs_file_set_open_context(filp, ctx);
+	put_nfs_open_context(ctx);
+	nfs_fscache_open_file(inode, filp);
+	return 0;
+}
+
+/*
+ * This function is called whenever some part of NFS notices that
+ * the cached attributes have to be refreshed.
+ */
+int
+__nfs_revalidate_inode(struct nfs_server *server, struct inode *inode)
+{
+	int		 status = -ESTALE;
+	struct nfs_fattr *fattr = NULL;
+	struct nfs_inode *nfsi = NFS_I(inode);
+
+	dfprintk(PAGECACHE, "NFS: revalidating (%s/%Lu)\n",
+		inode->i_sb->s_id, (unsigned long long)NFS_FILEID(inode));
+
+	trace_nfs_revalidate_inode_enter(inode);
+
+	if (is_bad_inode(inode))
+		goto out;
+	if (NFS_STALE(inode))
+		goto out;
+
+	/* pNFS: Attributes aren't updated until we layoutcommit */
+	if (S_ISREG(inode->i_mode)) {
+		status = pnfs_sync_inode(inode, false);
+		if (status)
+			goto out;
+	}
+
+	status = -ENOMEM;
+	fattr = nfs_alloc_fattr_with_label(NFS_SERVER(inode));
+	if (fattr == NULL)
+		goto out;
+
+	nfs_inc_stats(inode, NFSIOS_INODEREVALIDATE);
+
+	status = NFS_PROTO(inode)->getattr(server, NFS_FH(inode), fattr, inode);
+	if (status != 0) {
+		dfprintk(PAGECACHE, "nfs_revalidate_inode: (%s/%Lu) getattr failed, error=%d\n",
+			 inode->i_sb->s_id,
+			 (unsigned long long)NFS_FILEID(inode), status);
+		switch (status) {
+		case -ETIMEDOUT:
+			/* A soft timeout occurred. Use cached information? */
+			if (server->flags & NFS_MOUNT_SOFTREVAL)
+				status = 0;
+			break;
+		case -ESTALE:
+			if (!S_ISDIR(inode->i_mode))
+				nfs_set_inode_stale(inode);
+			else
+				nfs_zap_caches(inode);
+		}
+		goto out;
+	}
+
+	status = nfs_refresh_inode(inode, fattr);
+	if (status) {
+		dfprintk(PAGECACHE, "nfs_revalidate_inode: (%s/%Lu) refresh failed, error=%d\n",
+			 inode->i_sb->s_id,
+			 (unsigned long long)NFS_FILEID(inode), status);
+		goto out;
+	}
+
+	if (nfsi->cache_validity & NFS_INO_INVALID_ACL)
+		nfs_zap_acl_cache(inode);
+
+	nfs_setsecurity(inode, fattr);
+
+	dfprintk(PAGECACHE, "NFS: (%s/%Lu) revalidation complete\n",
+		inode->i_sb->s_id,
+		(unsigned long long)NFS_FILEID(inode));
+
+out:
+	nfs_free_fattr(fattr);
+	trace_nfs_revalidate_inode_exit(inode, status);
+	return status;
+}
+
+int nfs_attribute_cache_expired(struct inode *inode)
+{
+	if (nfs_have_delegated_attributes(inode))
+		return 0;
+	return nfs_attribute_timeout(inode);
+}
+
+/**
+ * nfs_revalidate_inode - Revalidate the inode attributes
+ * @inode: pointer to inode struct
+ * @flags: cache flags to check
+ *
+ * Updates inode attribute information by retrieving the data from the server.
+ */
+int nfs_revalidate_inode(struct inode *inode, unsigned long flags)
+{
+	if (!nfs_check_cache_invalid(inode, flags))
+		return NFS_STALE(inode) ? -ESTALE : 0;
+	return __nfs_revalidate_inode(NFS_SERVER(inode), inode);
+}
+EXPORT_SYMBOL_GPL(nfs_revalidate_inode);
+
+static int nfs_invalidate_mapping(struct inode *inode, struct address_space *mapping)
+{
+	int ret;
+
+	nfs_fscache_invalidate(inode, 0);
+	if (mapping->nrpages != 0) {
+		if (S_ISREG(inode->i_mode)) {
+			ret = nfs_sync_mapping(mapping);
+			if (ret < 0)
+				return ret;
+		}
+		ret = invalidate_inode_pages2(mapping);
+		if (ret < 0)
+			return ret;
+	}
+	nfs_inc_stats(inode, NFSIOS_DATAINVALIDATE);
+
+	dfprintk(PAGECACHE, "NFS: (%s/%Lu) data cache invalidated\n",
+			inode->i_sb->s_id,
+			(unsigned long long)NFS_FILEID(inode));
+	return 0;
+}
+
+/**
+ * nfs_clear_invalid_mapping - Conditionally clear a mapping
+ * @mapping: pointer to mapping
+ *
+ * If the NFS_INO_INVALID_DATA inode flag is set, clear the mapping.
+ */
+int nfs_clear_invalid_mapping(struct address_space *mapping)
+{
+	struct inode *inode = mapping->host;
+	struct nfs_inode *nfsi = NFS_I(inode);
+	unsigned long *bitlock = &nfsi->flags;
+	int ret = 0;
+
+	/*
+	 * We must clear NFS_INO_INVALID_DATA first to ensure that
+	 * invalidations that come in while we're shooting down the mappings
+	 * are respected. But, that leaves a race window where one revalidator
+	 * can clear the flag, and then another checks it before the mapping
+	 * gets invalidated. Fix that by serializing access to this part of
+	 * the function.
+	 *
+	 * At the same time, we need to allow other tasks to see whether we
+	 * might be in the middle of invalidating the pages, so we only set
+	 * the bit lock here if it looks like we're going to be doing that.
+	 */
+	for (;;) {
+		ret = wait_on_bit_action(bitlock, NFS_INO_INVALIDATING,
+					 nfs_wait_bit_killable,
+					 TASK_KILLABLE|TASK_FREEZABLE_UNSAFE);
+		if (ret)
+			goto out;
+		spin_lock(&inode->i_lock);
+		if (test_bit(NFS_INO_INVALIDATING, bitlock)) {
+			spin_unlock(&inode->i_lock);
+			continue;
+		}
+		if (nfsi->cache_validity & NFS_INO_INVALID_DATA)
+			break;
+		spin_unlock(&inode->i_lock);
+		goto out;
+	}
+
+	set_bit(NFS_INO_INVALIDATING, bitlock);
+	smp_wmb();
+	nfsi->cache_validity &=
+		~(NFS_INO_INVALID_DATA | NFS_INO_DATA_INVAL_DEFER);
+	spin_unlock(&inode->i_lock);
+	trace_nfs_invalidate_mapping_enter(inode);
+	ret = nfs_invalidate_mapping(inode, mapping);
+	trace_nfs_invalidate_mapping_exit(inode, ret);
+
+	clear_bit_unlock(NFS_INO_INVALIDATING, bitlock);
+	smp_mb__after_atomic();
+	wake_up_bit(bitlock, NFS_INO_INVALIDATING);
+out:
+	return ret;
+}
+
+bool nfs_mapping_need_revalidate_inode(struct inode *inode)
+{
+	return nfs_check_cache_invalid(inode, NFS_INO_INVALID_CHANGE) ||
+		NFS_STALE(inode);
+}
+
+int nfs_revalidate_mapping_rcu(struct inode *inode)
+{
+	struct nfs_inode *nfsi = NFS_I(inode);
+	unsigned long *bitlock = &nfsi->flags;
+	int ret = 0;
+
+	if (IS_SWAPFILE(inode))
+		goto out;
+	if (nfs_mapping_need_revalidate_inode(inode)) {
+		ret = -ECHILD;
+		goto out;
+	}
+	spin_lock(&inode->i_lock);
+	if (test_bit(NFS_INO_INVALIDATING, bitlock) ||
+	    (nfsi->cache_validity & NFS_INO_INVALID_DATA))
+		ret = -ECHILD;
+	spin_unlock(&inode->i_lock);
+out:
+	return ret;
+}
+
+/**
+ * nfs_revalidate_mapping - Revalidate the pagecache
+ * @inode: pointer to host inode
+ * @mapping: pointer to mapping
+ */
+int nfs_revalidate_mapping(struct inode *inode, struct address_space *mapping)
+{
+	/* swapfiles are not supposed to be shared. */
+	if (IS_SWAPFILE(inode))
+		return 0;
+
+	if (nfs_mapping_need_revalidate_inode(inode)) {
+		int ret = __nfs_revalidate_inode(NFS_SERVER(inode), inode);
+		if (ret < 0)
+			return ret;
+	}
+
+	return nfs_clear_invalid_mapping(mapping);
+}
+
+static bool nfs_file_has_writers(struct nfs_inode *nfsi)
+{
+	struct inode *inode = &nfsi->vfs_inode;
+
+	if (!S_ISREG(inode->i_mode))
+		return false;
+	if (list_empty(&nfsi->open_files))
+		return false;
+	return inode_is_open_for_write(inode);
+}
+
+static bool nfs_file_has_buffered_writers(struct nfs_inode *nfsi)
+{
+	return nfs_file_has_writers(nfsi) && nfs_file_io_is_buffered(nfsi);
+}
+
+static void nfs_wcc_update_inode(struct inode *inode, struct nfs_fattr *fattr)
+{
+	struct timespec64 ts;
+
+	if ((fattr->valid & NFS_ATTR_FATTR_PRECHANGE)
+			&& (fattr->valid & NFS_ATTR_FATTR_CHANGE)
+			&& inode_eq_iversion_raw(inode, fattr->pre_change_attr)) {
+		inode_set_iversion_raw(inode, fattr->change_attr);
+		if (S_ISDIR(inode->i_mode))
+			nfs_set_cache_invalid(inode, NFS_INO_INVALID_DATA);
+		else if (nfs_server_capable(inode, NFS_CAP_XATTR))
+			nfs_set_cache_invalid(inode, NFS_INO_INVALID_XATTR);
+	}
+	/* If we have atomic WCC data, we may update some attributes */
+	ts = inode->i_ctime;
+	if ((fattr->valid & NFS_ATTR_FATTR_PRECTIME)
+			&& (fattr->valid & NFS_ATTR_FATTR_CTIME)
+			&& timespec64_equal(&ts, &fattr->pre_ctime)) {
+		inode->i_ctime = fattr->ctime;
+	}
+
+	ts = inode->i_mtime;
+	if ((fattr->valid & NFS_ATTR_FATTR_PREMTIME)
+			&& (fattr->valid & NFS_ATTR_FATTR_MTIME)
+			&& timespec64_equal(&ts, &fattr->pre_mtime)) {
+		inode->i_mtime = fattr->mtime;
+	}
+	if ((fattr->valid & NFS_ATTR_FATTR_PRESIZE)
+			&& (fattr->valid & NFS_ATTR_FATTR_SIZE)
+			&& i_size_read(inode) == nfs_size_to_loff_t(fattr->pre_size)
+			&& !nfs_have_writebacks(inode)) {
+		trace_nfs_size_wcc(inode, fattr->size);
+		i_size_write(inode, nfs_size_to_loff_t(fattr->size));
+	}
+}
+
+/**
+ * nfs_check_inode_attributes - verify consistency of the inode attribute cache
+ * @inode: pointer to inode
+ * @fattr: updated attributes
+ *
+ * Verifies the attribute cache. If we have just changed the attributes,
+ * so that fattr carries weak cache consistency data, then it may
+ * also update the ctime/mtime/change_attribute.
+ */
+static int nfs_check_inode_attributes(struct inode *inode, struct nfs_fattr *fattr)
+{
+	struct nfs_inode *nfsi = NFS_I(inode);
+	loff_t cur_size, new_isize;
+	unsigned long invalid = 0;
+	struct timespec64 ts;
+
+	if (NFS_PROTO(inode)->have_delegation(inode, FMODE_READ))
+		return 0;
+
+	if (!(fattr->valid & NFS_ATTR_FATTR_FILEID)) {
+		/* Only a mounted-on-fileid? Just exit */
+		if (fattr->valid & NFS_ATTR_FATTR_MOUNTED_ON_FILEID)
+			return 0;
+	/* Has the inode gone and changed behind our back? */
+	} else if (nfsi->fileid != fattr->fileid) {
+		/* Is this perhaps the mounted-on fileid? */
+		if ((fattr->valid & NFS_ATTR_FATTR_MOUNTED_ON_FILEID) &&
+		    nfsi->fileid == fattr->mounted_on_fileid)
+			return 0;
+		return -ESTALE;
+	}
+	if ((fattr->valid & NFS_ATTR_FATTR_TYPE) && inode_wrong_type(inode, fattr->mode))
+		return -ESTALE;
+
+
+	if (!nfs_file_has_buffered_writers(nfsi)) {
+		/* Verify a few of the more important attributes */
+		if ((fattr->valid & NFS_ATTR_FATTR_CHANGE) != 0 && !inode_eq_iversion_raw(inode, fattr->change_attr))
+			invalid |= NFS_INO_INVALID_CHANGE;
+
+		ts = inode->i_mtime;
+		if ((fattr->valid & NFS_ATTR_FATTR_MTIME) && !timespec64_equal(&ts, &fattr->mtime))
+			invalid |= NFS_INO_INVALID_MTIME;
+
+		ts = inode->i_ctime;
+		if ((fattr->valid & NFS_ATTR_FATTR_CTIME) && !timespec64_equal(&ts, &fattr->ctime))
+			invalid |= NFS_INO_INVALID_CTIME;
+
+		if (fattr->valid & NFS_ATTR_FATTR_SIZE) {
+			cur_size = i_size_read(inode);
+			new_isize = nfs_size_to_loff_t(fattr->size);
+			if (cur_size != new_isize)
+				invalid |= NFS_INO_INVALID_SIZE;
+		}
+	}
+
+	/* Have any file permissions changed? */
+	if ((fattr->valid & NFS_ATTR_FATTR_MODE) && (inode->i_mode & S_IALLUGO) != (fattr->mode & S_IALLUGO))
+		invalid |= NFS_INO_INVALID_MODE;
+	if ((fattr->valid & NFS_ATTR_FATTR_OWNER) && !uid_eq(inode->i_uid, fattr->uid))
+		invalid |= NFS_INO_INVALID_OTHER;
+	if ((fattr->valid & NFS_ATTR_FATTR_GROUP) && !gid_eq(inode->i_gid, fattr->gid))
+		invalid |= NFS_INO_INVALID_OTHER;
+
+	/* Has the link count changed? */
+	if ((fattr->valid & NFS_ATTR_FATTR_NLINK) && inode->i_nlink != fattr->nlink)
+		invalid |= NFS_INO_INVALID_NLINK;
+
+	ts = inode->i_atime;
+	if ((fattr->valid & NFS_ATTR_FATTR_ATIME) && !timespec64_equal(&ts, &fattr->atime))
+		invalid |= NFS_INO_INVALID_ATIME;
+
+	if (invalid != 0)
+		nfs_set_cache_invalid(inode, invalid);
+
+	nfsi->read_cache_jiffies = fattr->time_start;
+	return 0;
+}
+
+static atomic_long_t nfs_attr_generation_counter;
+
+static unsigned long nfs_read_attr_generation_counter(void)
+{
+	return atomic_long_read(&nfs_attr_generation_counter);
+}
+
+unsigned long nfs_inc_attr_generation_counter(void)
+{
+	return atomic_long_inc_return(&nfs_attr_generation_counter);
+}
+EXPORT_SYMBOL_GPL(nfs_inc_attr_generation_counter);
+
+void nfs_fattr_init(struct nfs_fattr *fattr)
+{
+	fattr->valid = 0;
+	fattr->time_start = jiffies;
+	fattr->gencount = nfs_inc_attr_generation_counter();
+	fattr->owner_name = NULL;
+	fattr->group_name = NULL;
+}
+EXPORT_SYMBOL_GPL(nfs_fattr_init);
+
+/**
+ * nfs_fattr_set_barrier
+ * @fattr: attributes
+ *
+ * Used to set a barrier after an attribute was updated. This
+ * barrier ensures that older attributes from RPC calls that may
+ * have raced with our update cannot clobber these new values.
+ * Note that you are still responsible for ensuring that other
+ * operations which change the attribute on the server do not
+ * collide.
+ */
+void nfs_fattr_set_barrier(struct nfs_fattr *fattr)
+{
+	fattr->gencount = nfs_inc_attr_generation_counter();
+}
+
+struct nfs_fattr *nfs_alloc_fattr(void)
+{
+	struct nfs_fattr *fattr;
+
+	fattr = kmalloc(sizeof(*fattr), GFP_KERNEL);
+	if (fattr != NULL) {
+		nfs_fattr_init(fattr);
+		fattr->label = NULL;
+	}
+	return fattr;
+}
+EXPORT_SYMBOL_GPL(nfs_alloc_fattr);
+
+struct nfs_fattr *nfs_alloc_fattr_with_label(struct nfs_server *server)
+{
+	struct nfs_fattr *fattr = nfs_alloc_fattr();
+
+	if (!fattr)
+		return NULL;
+
+	fattr->label = nfs4_label_alloc(server, GFP_KERNEL);
+	if (IS_ERR(fattr->label)) {
+		kfree(fattr);
+		return NULL;
+	}
+
+	return fattr;
+}
+EXPORT_SYMBOL_GPL(nfs_alloc_fattr_with_label);
+
+struct nfs_fh *nfs_alloc_fhandle(void)
+{
+	struct nfs_fh *fh;
+
+	fh = kmalloc(sizeof(struct nfs_fh), GFP_KERNEL);
+	if (fh != NULL)
+		fh->size = 0;
+	return fh;
+}
+EXPORT_SYMBOL_GPL(nfs_alloc_fhandle);
+
+#ifdef NFS_DEBUG
+/*
+ * _nfs_display_fhandle_hash - calculate the crc32 hash for the filehandle
+ *                             in the same way that wireshark does
+ *
+ * @fh: file handle
+ *
+ * For debugging only.
+ */
+u32 _nfs_display_fhandle_hash(const struct nfs_fh *fh)
+{
+	/* wireshark uses 32-bit AUTODIN crc and does a bitwise
+	 * not on the result */
+	return nfs_fhandle_hash(fh);
+}
+EXPORT_SYMBOL_GPL(_nfs_display_fhandle_hash);
+
+/*
+ * _nfs_display_fhandle - display an NFS file handle on the console
+ *
+ * @fh: file handle to display
+ * @caption: display caption
+ *
+ * For debugging only.
+ */
+void _nfs_display_fhandle(const struct nfs_fh *fh, const char *caption)
+{
+	unsigned short i;
+
+	if (fh == NULL || fh->size == 0) {
+		printk(KERN_DEFAULT "%s at %p is empty\n", caption, fh);
+		return;
+	}
+
+	printk(KERN_DEFAULT "%s at %p is %u bytes, crc: 0x%08x:\n",
+	       caption, fh, fh->size, _nfs_display_fhandle_hash(fh));
+	for (i = 0; i < fh->size; i += 16) {
+		__be32 *pos = (__be32 *)&fh->data[i];
+
+		switch ((fh->size - i - 1) >> 2) {
+		case 0:
+			printk(KERN_DEFAULT " %08x\n",
+				be32_to_cpup(pos));
+			break;
+		case 1:
+			printk(KERN_DEFAULT " %08x %08x\n",
+				be32_to_cpup(pos), be32_to_cpup(pos + 1));
+			break;
+		case 2:
+			printk(KERN_DEFAULT " %08x %08x %08x\n",
+				be32_to_cpup(pos), be32_to_cpup(pos + 1),
+				be32_to_cpup(pos + 2));
+			break;
+		default:
+			printk(KERN_DEFAULT " %08x %08x %08x %08x\n",
+				be32_to_cpup(pos), be32_to_cpup(pos + 1),
+				be32_to_cpup(pos + 2), be32_to_cpup(pos + 3));
+		}
+	}
+}
+EXPORT_SYMBOL_GPL(_nfs_display_fhandle);
+#endif
+
+/**
+ * nfs_inode_attrs_cmp_generic - compare attributes
+ * @fattr: attributes
+ * @inode: pointer to inode
+ *
+ * Attempt to divine whether or not an RPC call reply carrying stale
+ * attributes got scheduled after another call carrying updated ones.
+ * Note also the check for wraparound of 'attr_gencount'
+ *
+ * The function returns '1' if it thinks the attributes in @fattr are
+ * more recent than the ones cached in @inode. Otherwise it returns
+ * the value '0'.
+ */
+static int nfs_inode_attrs_cmp_generic(const struct nfs_fattr *fattr,
+				       const struct inode *inode)
+{
+	unsigned long attr_gencount = NFS_I(inode)->attr_gencount;
+
+	return (long)(fattr->gencount - attr_gencount) > 0 ||
+	       (long)(attr_gencount - nfs_read_attr_generation_counter()) > 0;
+}
+
+/**
+ * nfs_inode_attrs_cmp_monotonic - compare attributes
+ * @fattr: attributes
+ * @inode: pointer to inode
+ *
+ * Attempt to divine whether or not an RPC call reply carrying stale
+ * attributes got scheduled after another call carrying updated ones.
+ *
+ * We assume that the server observes monotonic semantics for
+ * the change attribute, so a larger value means that the attributes in
+ * @fattr are more recent, in which case the function returns the
+ * value '1'.
+ * A return value of '0' indicates no measurable change
+ * A return value of '-1' means that the attributes in @inode are
+ * more recent.
+ */
+static int nfs_inode_attrs_cmp_monotonic(const struct nfs_fattr *fattr,
+					 const struct inode *inode)
+{
+	s64 diff = fattr->change_attr - inode_peek_iversion_raw(inode);
+	if (diff > 0)
+		return 1;
+	return diff == 0 ? 0 : -1;
+}
+
+/**
+ * nfs_inode_attrs_cmp_strict_monotonic - compare attributes
+ * @fattr: attributes
+ * @inode: pointer to inode
+ *
+ * Attempt to divine whether or not an RPC call reply carrying stale
+ * attributes got scheduled after another call carrying updated ones.
+ *
+ * We assume that the server observes strictly monotonic semantics for
+ * the change attribute, so a larger value means that the attributes in
+ * @fattr are more recent, in which case the function returns the
+ * value '1'.
+ * A return value of '-1' means that the attributes in @inode are
+ * more recent or unchanged.
+ */
+static int nfs_inode_attrs_cmp_strict_monotonic(const struct nfs_fattr *fattr,
+						const struct inode *inode)
+{
+	return  nfs_inode_attrs_cmp_monotonic(fattr, inode) > 0 ? 1 : -1;
+}
+
+/**
+ * nfs_inode_attrs_cmp - compare attributes
+ * @fattr: attributes
+ * @inode: pointer to inode
+ *
+ * This function returns '1' if it thinks the attributes in @fattr are
+ * more recent than the ones cached in @inode. It returns '-1' if
+ * the attributes in @inode are more recent than the ones in @fattr,
+ * and it returns 0 if not sure.
+ */
+static int nfs_inode_attrs_cmp(const struct nfs_fattr *fattr,
+			       const struct inode *inode)
+{
+	if (nfs_inode_attrs_cmp_generic(fattr, inode) > 0)
+		return 1;
+	switch (NFS_SERVER(inode)->change_attr_type) {
+	case NFS4_CHANGE_TYPE_IS_UNDEFINED:
+		break;
+	case NFS4_CHANGE_TYPE_IS_TIME_METADATA:
+		if (!(fattr->valid & NFS_ATTR_FATTR_CHANGE))
+			break;
+		return nfs_inode_attrs_cmp_monotonic(fattr, inode);
+	default:
+		if (!(fattr->valid & NFS_ATTR_FATTR_CHANGE))
+			break;
+		return nfs_inode_attrs_cmp_strict_monotonic(fattr, inode);
+	}
+	return 0;
+}
+
+/**
+ * nfs_inode_finish_partial_attr_update - complete a previous inode update
+ * @fattr: attributes
+ * @inode: pointer to inode
+ *
+ * Returns '1' if the last attribute update left the inode cached
+ * attributes in a partially unrevalidated state, and @fattr
+ * matches the change attribute of that partial update.
+ * Otherwise returns '0'.
+ */
+static int nfs_inode_finish_partial_attr_update(const struct nfs_fattr *fattr,
+						const struct inode *inode)
+{
+	const unsigned long check_valid =
+		NFS_INO_INVALID_ATIME | NFS_INO_INVALID_CTIME |
+		NFS_INO_INVALID_MTIME | NFS_INO_INVALID_SIZE |
+		NFS_INO_INVALID_BLOCKS | NFS_INO_INVALID_OTHER |
+		NFS_INO_INVALID_NLINK;
+	unsigned long cache_validity = NFS_I(inode)->cache_validity;
+	enum nfs4_change_attr_type ctype = NFS_SERVER(inode)->change_attr_type;
+
+	if (ctype != NFS4_CHANGE_TYPE_IS_UNDEFINED &&
+	    !(cache_validity & NFS_INO_INVALID_CHANGE) &&
+	    (cache_validity & check_valid) != 0 &&
+	    (fattr->valid & NFS_ATTR_FATTR_CHANGE) != 0 &&
+	    nfs_inode_attrs_cmp_monotonic(fattr, inode) == 0)
+		return 1;
+	return 0;
+}
+
+static int nfs_refresh_inode_locked(struct inode *inode,
+				    struct nfs_fattr *fattr)
+{
+	int attr_cmp = nfs_inode_attrs_cmp(fattr, inode);
+	int ret = 0;
+
+	trace_nfs_refresh_inode_enter(inode);
+
+	if (attr_cmp > 0 || nfs_inode_finish_partial_attr_update(fattr, inode))
+		ret = nfs_update_inode(inode, fattr);
+	else if (attr_cmp == 0)
+		ret = nfs_check_inode_attributes(inode, fattr);
+
+	trace_nfs_refresh_inode_exit(inode, ret);
+	return ret;
+}
+
+/**
+ * nfs_refresh_inode - try to update the inode attribute cache
+ * @inode: pointer to inode
+ * @fattr: updated attributes
+ *
+ * Check that an RPC call that returned attributes has not overlapped with
+ * other recent updates of the inode metadata, then decide whether it is
+ * safe to do a full update of the inode attributes, or whether just to
+ * call nfs_check_inode_attributes.
+ */
+int nfs_refresh_inode(struct inode *inode, struct nfs_fattr *fattr)
+{
+	int status;
+
+	if ((fattr->valid & NFS_ATTR_FATTR) == 0)
+		return 0;
+	spin_lock(&inode->i_lock);
+	status = nfs_refresh_inode_locked(inode, fattr);
+	spin_unlock(&inode->i_lock);
+
+	return status;
+}
+EXPORT_SYMBOL_GPL(nfs_refresh_inode);
+
+static int nfs_post_op_update_inode_locked(struct inode *inode,
+		struct nfs_fattr *fattr, unsigned int invalid)
+{
+	if (S_ISDIR(inode->i_mode))
+		invalid |= NFS_INO_INVALID_DATA;
+	nfs_set_cache_invalid(inode, invalid);
+	if ((fattr->valid & NFS_ATTR_FATTR) == 0)
+		return 0;
+	return nfs_refresh_inode_locked(inode, fattr);
+}
+
+/**
+ * nfs_post_op_update_inode - try to update the inode attribute cache
+ * @inode: pointer to inode
+ * @fattr: updated attributes
+ *
+ * After an operation that has changed the inode metadata, mark the
+ * attribute cache as being invalid, then try to update it.
+ *
+ * NB: if the server didn't return any post op attributes, this
+ * function will force the retrieval of attributes before the next
+ * NFS request.  Thus it should be used only for operations that
+ * are expected to change one or more attributes, to avoid
+ * unnecessary NFS requests and trips through nfs_update_inode().
+ */
+int nfs_post_op_update_inode(struct inode *inode, struct nfs_fattr *fattr)
+{
+	int status;
+
+	spin_lock(&inode->i_lock);
+	nfs_fattr_set_barrier(fattr);
+	status = nfs_post_op_update_inode_locked(inode, fattr,
+			NFS_INO_INVALID_CHANGE
+			| NFS_INO_INVALID_CTIME
+			| NFS_INO_REVAL_FORCED);
+	spin_unlock(&inode->i_lock);
+
+	return status;
+}
+EXPORT_SYMBOL_GPL(nfs_post_op_update_inode);
+
+/**
+ * nfs_post_op_update_inode_force_wcc_locked - update the inode attribute cache
+ * @inode: pointer to inode
+ * @fattr: updated attributes
+ *
+ * After an operation that has changed the inode metadata, mark the
+ * attribute cache as being invalid, then try to update it. Fake up
+ * weak cache consistency data, if none exist.
+ *
+ * This function is mainly designed to be used by the ->write_done() functions.
+ */
+int nfs_post_op_update_inode_force_wcc_locked(struct inode *inode, struct nfs_fattr *fattr)
+{
+	int attr_cmp = nfs_inode_attrs_cmp(fattr, inode);
+	int status;
+
+	/* Don't do a WCC update if these attributes are already stale */
+	if (attr_cmp < 0)
+		return 0;
+	if ((fattr->valid & NFS_ATTR_FATTR) == 0 || !attr_cmp) {
+		fattr->valid &= ~(NFS_ATTR_FATTR_PRECHANGE
+				| NFS_ATTR_FATTR_PRESIZE
+				| NFS_ATTR_FATTR_PREMTIME
+				| NFS_ATTR_FATTR_PRECTIME);
+		goto out_noforce;
+	}
+	if ((fattr->valid & NFS_ATTR_FATTR_CHANGE) != 0 &&
+			(fattr->valid & NFS_ATTR_FATTR_PRECHANGE) == 0) {
+		fattr->pre_change_attr = inode_peek_iversion_raw(inode);
+		fattr->valid |= NFS_ATTR_FATTR_PRECHANGE;
+	}
+	if ((fattr->valid & NFS_ATTR_FATTR_CTIME) != 0 &&
+			(fattr->valid & NFS_ATTR_FATTR_PRECTIME) == 0) {
+		fattr->pre_ctime = inode->i_ctime;
+		fattr->valid |= NFS_ATTR_FATTR_PRECTIME;
+	}
+	if ((fattr->valid & NFS_ATTR_FATTR_MTIME) != 0 &&
+			(fattr->valid & NFS_ATTR_FATTR_PREMTIME) == 0) {
+		fattr->pre_mtime = inode->i_mtime;
+		fattr->valid |= NFS_ATTR_FATTR_PREMTIME;
+	}
+	if ((fattr->valid & NFS_ATTR_FATTR_SIZE) != 0 &&
+			(fattr->valid & NFS_ATTR_FATTR_PRESIZE) == 0) {
+		fattr->pre_size = i_size_read(inode);
+		fattr->valid |= NFS_ATTR_FATTR_PRESIZE;
+	}
+out_noforce:
+	status = nfs_post_op_update_inode_locked(inode, fattr,
+			NFS_INO_INVALID_CHANGE
+			| NFS_INO_INVALID_CTIME
+			| NFS_INO_INVALID_MTIME
+			| NFS_INO_INVALID_BLOCKS);
+	return status;
+}
+
+/**
+ * nfs_post_op_update_inode_force_wcc - try to update the inode attribute cache
+ * @inode: pointer to inode
+ * @fattr: updated attributes
+ *
+ * After an operation that has changed the inode metadata, mark the
+ * attribute cache as being invalid, then try to update it. Fake up
+ * weak cache consistency data, if none exist.
+ *
+ * This function is mainly designed to be used by the ->write_done() functions.
+ */
+int nfs_post_op_update_inode_force_wcc(struct inode *inode, struct nfs_fattr *fattr)
+{
+	int status;
+
+	spin_lock(&inode->i_lock);
+	nfs_fattr_set_barrier(fattr);
+	status = nfs_post_op_update_inode_force_wcc_locked(inode, fattr);
+	spin_unlock(&inode->i_lock);
+	return status;
+}
+EXPORT_SYMBOL_GPL(nfs_post_op_update_inode_force_wcc);
+
+
+/*
+ * Many nfs protocol calls return the new file attributes after
+ * an operation.  Here we update the inode to reflect the state
+ * of the server's inode.
+ *
+ * This is a bit tricky because we have to make sure all dirty pages
+ * have been sent off to the server before calling invalidate_inode_pages.
+ * To make sure no other process adds more write requests while we try
+ * our best to flush them, we make them sleep during the attribute refresh.
+ *
+ * A very similar scenario holds for the dir cache.
+ */
+static int nfs_update_inode(struct inode *inode, struct nfs_fattr *fattr)
+{
+	struct nfs_server *server = NFS_SERVER(inode);
+	struct nfs_inode *nfsi = NFS_I(inode);
+	loff_t cur_isize, new_isize;
+	u64 fattr_supported = server->fattr_valid;
+	unsigned long invalid = 0;
+	unsigned long now = jiffies;
+	unsigned long save_cache_validity;
+	bool have_writers = nfs_file_has_buffered_writers(nfsi);
+	bool cache_revalidated = true;
+	bool attr_changed = false;
+	bool have_delegation;
+
+	dfprintk(VFS, "NFS: %s(%s/%lu fh_crc=0x%08x ct=%d info=0x%x)\n",
+			__func__, inode->i_sb->s_id, inode->i_ino,
+			nfs_display_fhandle_hash(NFS_FH(inode)),
+			atomic_read(&inode->i_count), fattr->valid);
+
+	if (!(fattr->valid & NFS_ATTR_FATTR_FILEID)) {
+		/* Only a mounted-on-fileid? Just exit */
+		if (fattr->valid & NFS_ATTR_FATTR_MOUNTED_ON_FILEID)
+			return 0;
+	/* Has the inode gone and changed behind our back? */
+	} else if (nfsi->fileid != fattr->fileid) {
+		/* Is this perhaps the mounted-on fileid? */
+		if ((fattr->valid & NFS_ATTR_FATTR_MOUNTED_ON_FILEID) &&
+		    nfsi->fileid == fattr->mounted_on_fileid)
+			return 0;
+		printk(KERN_ERR "NFS: server %s error: fileid changed\n"
+			"fsid %s: expected fileid 0x%Lx, got 0x%Lx\n",
+			NFS_SERVER(inode)->nfs_client->cl_hostname,
+			inode->i_sb->s_id, (long long)nfsi->fileid,
+			(long long)fattr->fileid);
+		goto out_err;
+	}
+
+	/*
+	 * Make sure the inode's type hasn't changed.
+	 */
+	if ((fattr->valid & NFS_ATTR_FATTR_TYPE) && inode_wrong_type(inode, fattr->mode)) {
+		/*
+		* Big trouble! The inode has become a different object.
+		*/
+		printk(KERN_DEBUG "NFS: %s: inode %lu mode changed, %07o to %07o\n",
+				__func__, inode->i_ino, inode->i_mode, fattr->mode);
+		goto out_err;
+	}
+
+	/* Update the fsid? */
+	if (S_ISDIR(inode->i_mode) && (fattr->valid & NFS_ATTR_FATTR_FSID) &&
+			!nfs_fsid_equal(&server->fsid, &fattr->fsid) &&
+			!IS_AUTOMOUNT(inode))
+		server->fsid = fattr->fsid;
+
+	/* Save the delegation state before clearing cache_validity */
+	have_delegation = nfs_have_delegated_attributes(inode);
+
+	/*
+	 * Update the read time so we don't revalidate too often.
+	 */
+	nfsi->read_cache_jiffies = fattr->time_start;
+
+	save_cache_validity = nfsi->cache_validity;
+	nfsi->cache_validity &= ~(NFS_INO_INVALID_ATTR
+			| NFS_INO_INVALID_ATIME
+			| NFS_INO_REVAL_FORCED
+			| NFS_INO_INVALID_BLOCKS);
+
+	/* Do atomic weak cache consistency updates */
+	nfs_wcc_update_inode(inode, fattr);
+
+	if (pnfs_layoutcommit_outstanding(inode)) {
+		nfsi->cache_validity |=
+			save_cache_validity &
+			(NFS_INO_INVALID_CHANGE | NFS_INO_INVALID_CTIME |
+			 NFS_INO_INVALID_MTIME | NFS_INO_INVALID_SIZE |
+			 NFS_INO_INVALID_BLOCKS);
+		cache_revalidated = false;
+	}
+
+	/* More cache consistency checks */
+	if (fattr->valid & NFS_ATTR_FATTR_CHANGE) {
+		if (!inode_eq_iversion_raw(inode, fattr->change_attr)) {
+			/* Could it be a race with writeback? */
+			if (!(have_writers || have_delegation)) {
+				invalid |= NFS_INO_INVALID_DATA
+					| NFS_INO_INVALID_ACCESS
+					| NFS_INO_INVALID_ACL
+					| NFS_INO_INVALID_XATTR;
+				/* Force revalidate of all attributes */
+				save_cache_validity |= NFS_INO_INVALID_CTIME
+					| NFS_INO_INVALID_MTIME
+					| NFS_INO_INVALID_SIZE
+					| NFS_INO_INVALID_BLOCKS
+					| NFS_INO_INVALID_NLINK
+					| NFS_INO_INVALID_MODE
+					| NFS_INO_INVALID_OTHER;
+				if (S_ISDIR(inode->i_mode))
+					nfs_force_lookup_revalidate(inode);
+				attr_changed = true;
+				dprintk("NFS: change_attr change on server for file %s/%ld\n",
+						inode->i_sb->s_id,
+						inode->i_ino);
+			} else if (!have_delegation)
+				nfsi->cache_validity |= NFS_INO_DATA_INVAL_DEFER;
+			inode_set_iversion_raw(inode, fattr->change_attr);
+		}
+	} else {
+		nfsi->cache_validity |=
+			save_cache_validity & NFS_INO_INVALID_CHANGE;
+		if (!have_delegation ||
+		    (nfsi->cache_validity & NFS_INO_INVALID_CHANGE) != 0)
+			cache_revalidated = false;
+	}
+
+	if (fattr->valid & NFS_ATTR_FATTR_MTIME)
+		inode->i_mtime = fattr->mtime;
+	else if (fattr_supported & NFS_ATTR_FATTR_MTIME)
+		nfsi->cache_validity |=
+			save_cache_validity & NFS_INO_INVALID_MTIME;
+
+	if (fattr->valid & NFS_ATTR_FATTR_CTIME)
+		inode->i_ctime = fattr->ctime;
+	else if (fattr_supported & NFS_ATTR_FATTR_CTIME)
+		nfsi->cache_validity |=
+			save_cache_validity & NFS_INO_INVALID_CTIME;
+
+	/* Check if our cached file size is stale */
+	if (fattr->valid & NFS_ATTR_FATTR_SIZE) {
+		new_isize = nfs_size_to_loff_t(fattr->size);
+		cur_isize = i_size_read(inode);
+		if (new_isize != cur_isize && !have_delegation) {
+			/* Do we perhaps have any outstanding writes, or has
+			 * the file grown beyond our last write? */
+			if (!nfs_have_writebacks(inode) || new_isize > cur_isize) {
+				trace_nfs_size_update(inode, new_isize);
+				i_size_write(inode, new_isize);
+				if (!have_writers)
+					invalid |= NFS_INO_INVALID_DATA;
+			}
+		}
+		if (new_isize == 0 &&
+		    !(fattr->valid & (NFS_ATTR_FATTR_SPACE_USED |
+				      NFS_ATTR_FATTR_BLOCKS_USED))) {
+			fattr->du.nfs3.used = 0;
+			fattr->valid |= NFS_ATTR_FATTR_SPACE_USED;
+		}
+	} else
+		nfsi->cache_validity |=
+			save_cache_validity & NFS_INO_INVALID_SIZE;
+
+	if (fattr->valid & NFS_ATTR_FATTR_ATIME)
+		inode->i_atime = fattr->atime;
+	else if (fattr_supported & NFS_ATTR_FATTR_ATIME)
+		nfsi->cache_validity |=
+			save_cache_validity & NFS_INO_INVALID_ATIME;
+
+	if (fattr->valid & NFS_ATTR_FATTR_MODE) {
+		if ((inode->i_mode & S_IALLUGO) != (fattr->mode & S_IALLUGO)) {
+			umode_t newmode = inode->i_mode & S_IFMT;
+			newmode |= fattr->mode & S_IALLUGO;
+			inode->i_mode = newmode;
+			invalid |= NFS_INO_INVALID_ACCESS
+				| NFS_INO_INVALID_ACL;
+		}
+	} else if (fattr_supported & NFS_ATTR_FATTR_MODE)
+		nfsi->cache_validity |=
+			save_cache_validity & NFS_INO_INVALID_MODE;
+
+	if (fattr->valid & NFS_ATTR_FATTR_OWNER) {
+		if (!uid_eq(inode->i_uid, fattr->uid)) {
+			invalid |= NFS_INO_INVALID_ACCESS
+				| NFS_INO_INVALID_ACL;
+			inode->i_uid = fattr->uid;
+		}
+	} else if (fattr_supported & NFS_ATTR_FATTR_OWNER)
+		nfsi->cache_validity |=
+			save_cache_validity & NFS_INO_INVALID_OTHER;
+
+	if (fattr->valid & NFS_ATTR_FATTR_GROUP) {
+		if (!gid_eq(inode->i_gid, fattr->gid)) {
+			invalid |= NFS_INO_INVALID_ACCESS
+				| NFS_INO_INVALID_ACL;
+			inode->i_gid = fattr->gid;
+		}
+	} else if (fattr_supported & NFS_ATTR_FATTR_GROUP)
+		nfsi->cache_validity |=
+			save_cache_validity & NFS_INO_INVALID_OTHER;
+
+	if (fattr->valid & NFS_ATTR_FATTR_NLINK) {
+		if (inode->i_nlink != fattr->nlink)
+			set_nlink(inode, fattr->nlink);
+	} else if (fattr_supported & NFS_ATTR_FATTR_NLINK)
+		nfsi->cache_validity |=
+			save_cache_validity & NFS_INO_INVALID_NLINK;
+
+	if (fattr->valid & NFS_ATTR_FATTR_SPACE_USED) {
+		/*
+		 * report the blocks in 512byte units
+		 */
+		inode->i_blocks = nfs_calc_block_size(fattr->du.nfs3.used);
+	} else if (fattr_supported & NFS_ATTR_FATTR_SPACE_USED)
+		nfsi->cache_validity |=
+			save_cache_validity & NFS_INO_INVALID_BLOCKS;
+
+	if (fattr->valid & NFS_ATTR_FATTR_BLOCKS_USED)
+		inode->i_blocks = fattr->du.nfs2.blocks;
+	else if (fattr_supported & NFS_ATTR_FATTR_BLOCKS_USED)
+		nfsi->cache_validity |=
+			save_cache_validity & NFS_INO_INVALID_BLOCKS;
+
+	/* Update attrtimeo value if we're out of the unstable period */
+	if (attr_changed) {
+		nfs_inc_stats(inode, NFSIOS_ATTRINVALIDATE);
+		nfsi->attrtimeo = NFS_MINATTRTIMEO(inode);
+		nfsi->attrtimeo_timestamp = now;
+		/* Set barrier to be more recent than all outstanding updates */
+		nfsi->attr_gencount = nfs_inc_attr_generation_counter();
+	} else {
+		if (cache_revalidated) {
+			if (!time_in_range_open(now, nfsi->attrtimeo_timestamp,
+				nfsi->attrtimeo_timestamp + nfsi->attrtimeo)) {
+				nfsi->attrtimeo <<= 1;
+				if (nfsi->attrtimeo > NFS_MAXATTRTIMEO(inode))
+					nfsi->attrtimeo = NFS_MAXATTRTIMEO(inode);
+			}
+			nfsi->attrtimeo_timestamp = now;
+		}
+		/* Set the barrier to be more recent than this fattr */
+		if ((long)(fattr->gencount - nfsi->attr_gencount) > 0)
+			nfsi->attr_gencount = fattr->gencount;
+	}
+
+	/* Don't invalidate the data if we were to blame */
+	if (!(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode)
+				|| S_ISLNK(inode->i_mode)))
+		invalid &= ~NFS_INO_INVALID_DATA;
+	nfs_set_cache_invalid(inode, invalid);
+
+	return 0;
+ out_err:
+	/*
+	 * No need to worry about unhashing the dentry, as the
+	 * lookup validation will know that the inode is bad.
+	 * (But we fall through to invalidate the caches.)
+	 */
+	nfs_set_inode_stale_locked(inode);
+	return -ESTALE;
+}
+
+struct inode *nfs_alloc_inode(struct super_block *sb)
+{
+	struct nfs_inode *nfsi;
+	nfsi = alloc_inode_sb(sb, nfs_inode_cachep, GFP_KERNEL);
+	if (!nfsi)
+		return NULL;
+	nfsi->flags = 0UL;
+	nfsi->cache_validity = 0UL;
+#if IS_ENABLED(CONFIG_NFS_V4)
+	nfsi->nfs4_acl = NULL;
+#endif /* CONFIG_NFS_V4 */
+#ifdef CONFIG_NFS_V4_2
+	nfsi->xattr_cache = NULL;
+#endif
+	return &nfsi->vfs_inode;
+}
+EXPORT_SYMBOL_GPL(nfs_alloc_inode);
+
+void nfs_free_inode(struct inode *inode)
+{
+	kmem_cache_free(nfs_inode_cachep, NFS_I(inode));
+}
+EXPORT_SYMBOL_GPL(nfs_free_inode);
+
+static inline void nfs4_init_once(struct nfs_inode *nfsi)
+{
+#if IS_ENABLED(CONFIG_NFS_V4)
+	INIT_LIST_HEAD(&nfsi->open_states);
+	nfsi->delegation = NULL;
+	init_rwsem(&nfsi->rwsem);
+	nfsi->layout = NULL;
+#endif
+}
+
+static void init_once(void *foo)
+{
+	struct nfs_inode *nfsi = foo;
+
+	inode_init_once(&nfsi->vfs_inode);
+	INIT_LIST_HEAD(&nfsi->open_files);
+	INIT_LIST_HEAD(&nfsi->access_cache_entry_lru);
+	INIT_LIST_HEAD(&nfsi->access_cache_inode_lru);
+	nfs4_init_once(nfsi);
+}
+
+static int __init nfs_init_inodecache(void)
+{
+	nfs_inode_cachep = kmem_cache_create("nfs_inode_cache",
+					     sizeof(struct nfs_inode),
+					     0, (SLAB_RECLAIM_ACCOUNT|
+						SLAB_MEM_SPREAD|SLAB_ACCOUNT),
+					     init_once);
+	if (nfs_inode_cachep == NULL)
+		return -ENOMEM;
+
+	return 0;
+}
+
+static void nfs_destroy_inodecache(void)
+{
+	/*
+	 * Make sure all delayed rcu free inodes are flushed before we
+	 * destroy cache.
+	 */
+	rcu_barrier();
+	kmem_cache_destroy(nfs_inode_cachep);
+}
+
+struct workqueue_struct *nfsiod_workqueue;
+EXPORT_SYMBOL_GPL(nfsiod_workqueue);
+
+/*
+ * start up the nfsiod workqueue
+ */
+static int nfsiod_start(void)
+{
+	struct workqueue_struct *wq;
+	dprintk("RPC:       creating workqueue nfsiod\n");
+	wq = alloc_workqueue("nfsiod", WQ_MEM_RECLAIM | WQ_UNBOUND, 0);
+	if (wq == NULL)
+		return -ENOMEM;
+	nfsiod_workqueue = wq;
+	return 0;
+}
+
+/*
+ * Destroy the nfsiod workqueue
+ */
+static void nfsiod_stop(void)
+{
+	struct workqueue_struct *wq;
+
+	wq = nfsiod_workqueue;
+	if (wq == NULL)
+		return;
+	nfsiod_workqueue = NULL;
+	destroy_workqueue(wq);
+}
+
+unsigned int nfs_net_id;
+EXPORT_SYMBOL_GPL(nfs_net_id);
+
+static int nfs_net_init(struct net *net)
+{
+	nfs_clients_init(net);
+	return nfs_fs_proc_net_init(net);
+}
+
+static void nfs_net_exit(struct net *net)
+{
+	nfs_fs_proc_net_exit(net);
+	nfs_clients_exit(net);
+}
+
+static struct pernet_operations nfs_net_ops = {
+	.init = nfs_net_init,
+	.exit = nfs_net_exit,
+	.id   = &nfs_net_id,
+	.size = sizeof(struct nfs_net),
+};
+
+/*
+ * Initialize NFS
+ */
+static int __init init_nfs_fs(void)
+{
+	int err;
+
+	err = nfs_sysfs_init();
+	if (err < 0)
+		goto out10;
+
+	err = register_pernet_subsys(&nfs_net_ops);
+	if (err < 0)
+		goto out9;
+
+	err = nfsiod_start();
+	if (err)
+		goto out7;
+
+	err = nfs_fs_proc_init();
+	if (err)
+		goto out6;
+
+	err = nfs_init_nfspagecache();
+	if (err)
+		goto out5;
+
+	err = nfs_init_inodecache();
+	if (err)
+		goto out4;
+
+	err = nfs_init_readpagecache();
+	if (err)
+		goto out3;
+
+	err = nfs_init_writepagecache();
+	if (err)
+		goto out2;
+
+	err = nfs_init_directcache();
+	if (err)
+		goto out1;
+
+	rpc_proc_register(&init_net, &nfs_rpcstat);
+
+	err = register_nfs_fs();
+	if (err)
+		goto out0;
+
+	return 0;
+out0:
+	rpc_proc_unregister(&init_net, "nfs");
+	nfs_destroy_directcache();
+out1:
+	nfs_destroy_writepagecache();
+out2:
+	nfs_destroy_readpagecache();
+out3:
+	nfs_destroy_inodecache();
+out4:
+	nfs_destroy_nfspagecache();
+out5:
+	nfs_fs_proc_exit();
+out6:
+	nfsiod_stop();
+out7:
+	unregister_pernet_subsys(&nfs_net_ops);
+out9:
+	nfs_sysfs_exit();
+out10:
+	return err;
+}
+
+static void __exit exit_nfs_fs(void)
+{
+	nfs_destroy_directcache();
+	nfs_destroy_writepagecache();
+	nfs_destroy_readpagecache();
+	nfs_destroy_inodecache();
+	nfs_destroy_nfspagecache();
+	unregister_pernet_subsys(&nfs_net_ops);
+	rpc_proc_unregister(&init_net, "nfs");
+	unregister_nfs_fs();
+	nfs_fs_proc_exit();
+	nfsiod_stop();
+	nfs_sysfs_exit();
+}
+
+/* Not quite true; I just maintain it */
+MODULE_AUTHOR("Olaf Kirch <okir@monad.swb.de>");
+MODULE_LICENSE("GPL");
+module_param(enable_ino64, bool, 0644);
+
+module_init(init_nfs_fs)
+module_exit(exit_nfs_fs)