Re: [PATCH 13/13] NFSv4.2: add client side xattr caching.

Schumaker, Anna
2020-03-12T20:48:25Z

On Wed, 2020-03-11 at 19:56 +0000, Frank van der Linden wrote:
> Implement client side caching for NFSv4.2 extended attributes. The cache
> is a per-inode hashtable, with name/value entries. There is one special
> entry for the listxattr cache.
>
> NFS inodes have a pointer to a cache structure. The cache structure is
> allocated on demand, freed when the cache is invalidated.
>
> Memory shrinkers keep the size in check. Large entries (> PAGE_SIZE)
> are collected by a separate shrinker, and freed more aggressively
> than others.
>
> Signed-off-by: Frank van der Linden <fllinden@amazon.com>
> ---
> fs/nfs/Makefile | 1 +
> fs/nfs/inode.c | 9 +-
> fs/nfs/internal.h | 20 +
> fs/nfs/nfs42proc.c | 12 +
> fs/nfs/nfs42xattr.c | 1083
> +++++++++++++++++++++++++++++++++++++++++++
> fs/nfs/nfs4proc.c | 42 +-
> fs/nfs/nfs4super.c | 10 +
> include/linux/nfs_fs.h | 6 +
> include/uapi/linux/nfs_fs.h | 1 +
> 9 files changed, 1177 insertions(+), 7 deletions(-)
> create mode 100644 fs/nfs/nfs42xattr.c
>
> diff --git a/fs/nfs/Makefile b/fs/nfs/Makefile
> index 2433c3e03cfa..191b3e9aa232 100644
> --- a/fs/nfs/Makefile
> +++ b/fs/nfs/Makefile
> @@ -31,6 +31,7 @@ nfsv4-$(CONFIG_NFS_USE_LEGACY_DNS) += cache_lib.o
> nfsv4-$(CONFIG_SYSCTL) += nfs4sysctl.o
> nfsv4-$(CONFIG_NFS_V4_1) += pnfs.o pnfs_dev.o pnfs_nfs.o
> nfsv4-$(CONFIG_NFS_V4_2) += nfs42proc.o
> +nfsv4-$(CONFIG_NFS_V4_2) += nfs42xattr.o

Oh, you should also be able to combine the two CONFIG_NFS_V4_2 lines here:
nfsv4-$(CONFIG_NFS_V4_2) += nfs42proc.o nfs42xattr.o

>
> obj-$(CONFIG_PNFS_FILE_LAYOUT) += filelayout/
> obj-$(CONFIG_PNFS_BLOCK) += blocklayout/
> diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
> index d2be152796ef..9d4952d2306b 100644
> --- a/fs/nfs/inode.c
> +++ b/fs/nfs/inode.c
> @@ -194,6 +194,7 @@ bool nfs_check_cache_invalid(struct inode *inode, unsigned
> long flags)
>
> return nfs_check_cache_invalid_not_delegated(inode, flags);
> }
> +EXPORT_SYMBOL_GPL(nfs_check_cache_invalid);
>
> static void nfs_set_cache_invalid(struct inode *inode, unsigned long flags)
> {
> @@ -235,11 +236,13 @@ static void nfs_zap_caches_locked(struct inode *inode)
> | NFS_INO_INVALID_DATA
> | NFS_INO_INVALID_ACCESS
> | NFS_INO_INVALID_ACL
> + | NFS_INO_INVALID_XATTR
> | NFS_INO_REVAL_PAGECACHE);
> } else
> nfs_set_cache_invalid(inode, NFS_INO_INVALID_ATTR
> | NFS_INO_INVALID_ACCESS
> | NFS_INO_INVALID_ACL
> + | NFS_INO_INVALID_XATTR
> | NFS_INO_REVAL_PAGECACHE);
> nfs_zap_label_cache_locked(nfsi);
> }
> @@ -1885,7 +1888,8 @@ static int nfs_update_inode(struct inode *inode, struct
> nfs_fattr *fattr)
> if (!(have_writers || have_delegation)) {
> invalid |= NFS_INO_INVALID_DATA
> | NFS_INO_INVALID_ACCESS
> - | NFS_INO_INVALID_ACL;
> + | NFS_INO_INVALID_ACL
> + | NFS_INO_INVALID_XATTR;
> /* Force revalidate of all attributes */
> save_cache_validity |= NFS_INO_INVALID_CTIME
> | NFS_INO_INVALID_MTIME
> @@ -2084,6 +2088,9 @@ struct inode *nfs_alloc_inode(struct super_block *sb)
> #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);
> diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h
> index 1e3a7e119c93..67b8e4f7c554 100644
> --- a/fs/nfs/internal.h
> +++ b/fs/nfs/internal.h
> @@ -575,6 +575,26 @@ extern void nfs4_test_session_trunk(struct rpc_clnt
> *clnt,
> struct rpc_xprt *xprt,
> void *data);
>
> +#ifdef CONFIG_NFS_V4_2
> +extern int __init nfs4_xattr_cache_init(void);
> +extern void nfs4_xattr_cache_exit(void);
> +extern void nfs4_xattr_cache_add(struct inode *inode, const char *name,
> + const char *buf, struct page **pages,
> + ssize_t buflen);
> +extern void nfs4_xattr_cache_remove(struct inode *inode, const char *name);
> +extern ssize_t nfs4_xattr_cache_get(struct inode *inode, const char *name,
> + char *buf, ssize_t buflen);
> +extern void nfs4_xattr_cache_set_list(struct inode *inode, const char *buf,
> + ssize_t buflen);
> +extern ssize_t nfs4_xattr_cache_list(struct inode *inode, char *buf,
> + ssize_t buflen);
> +extern void nfs4_xattr_cache_zap(struct inode *inode);
> +#else
> +static inline void nfs4_xattr_cache_zap(struct inode *inode)
> +{
> +}
> +#endif
> +
> static inline struct inode *nfs_igrab_and_active(struct inode *inode)
> {
> inode = igrab(inode);
> diff --git a/fs/nfs/nfs42proc.c b/fs/nfs/nfs42proc.c
> index 8c2e52bc986a..e200522469af 100644
> --- a/fs/nfs/nfs42proc.c
> +++ b/fs/nfs/nfs42proc.c
> @@ -1182,6 +1182,18 @@ static ssize_t _nfs42_proc_getxattr(struct inode
> *inode, const char *name,
> if (ret < 0)
> return ret;
>
> + /*
> + * Normally, the caching is done one layer up, but for successful
> + * RPCS, always cache the result here, even if the caller was
> + * just querying the length, or if the reply was too big for
> + * the caller. This avoids a second RPC in the case of the
> + * common query-alloc-retrieve cycle for xattrs.
> + *
> + * Note that xattr_len is always capped to XATTR_SIZE_MAX.
> + */
> +
> + nfs4_xattr_cache_add(inode, name, NULL, pages, res.xattr_len);
> +
> if (buflen) {
> if (res.xattr_len > buflen)
> return -ERANGE;
> diff --git a/fs/nfs/nfs42xattr.c b/fs/nfs/nfs42xattr.c
> new file mode 100644
> index 000000000000..23fdab977a2a
> --- /dev/null
> +++ b/fs/nfs/nfs42xattr.c
> @@ -0,0 +1,1083 @@
> +// SPDX-License-Identifier: GPL-2.0
> +
> +/*
> + * Copyright 2019, 2020 Amazon.com, Inc. or its affiliates. All rights
> reserved.
> + *
> + * User extended attribute client side cache functions.
> + *
> + * Author: Frank van der Linden <fllinden@amazon.com>
> + */
> +#include <linux/errno.h>
> +#include <linux/nfs_fs.h>
> +#include <linux/hashtable.h>
> +#include <linux/refcount.h>
> +#include <uapi/linux/xattr.h>
> +
> +#include "nfs4_fs.h"
> +#include "internal.h"
> +
> +/*
> + * User extended attributes client side caching is implemented by having
> + * a cache structure attached to NFS inodes. This structure is allocated
> + * when needed, and freed when the cache is zapped.
> + *
> + * The cache structure contains as hash table of entries, and a pointer
> + * to a special-cased entry for the listxattr cache.
> + *
> + * Accessing and allocating / freeing the caches is done via reference
> + * counting. The cache entries use a similar refcounting scheme.
> + *
> + * This makes freeing a cache, both from the shrinker and from the
> + * zap cache path, easy. It also means that, in current use cases,
> + * the large majority of inodes will not waste any memory, as they
> + * will never have any user extended attributes assigned to them.
> + *
> + * Attribute entries are hashed in to a simple hash table. They are
> + * also part of an LRU.
> + *
> + * There are three shrinkers.
> + *
> + * Two shrinkers deal with the cache entries themselves: one for
> + * large entries (> PAGE_SIZE), and one for smaller entries. The
> + * shrinker for the larger entries works more aggressively than
> + * those for the smaller entries.
> + *
> + * The other shrinker frees the cache structures themselves.
> + */
> +
> +/*
> + * 64 buckets is a good default. There is likely no reasonable
> + * workload that uses more than even 64 user extended attributes.
> + * You can certainly add a lot more - but you get what you ask for
> + * in those circumstances.
> + */
> +#define NFS4_XATTR_HASH_SIZE 64
> +
> +#define NFSDBG_FACILITY NFSDBG_XATTRCACHE
> +
> +struct nfs4_xattr_cache;
> +struct nfs4_xattr_entry;
> +
> +struct nfs4_xattr_bucket {
> + spinlock_t lock;
> + struct hlist_head hlist;
> + struct nfs4_xattr_cache *cache;
> + bool draining;
> +};
> +
> +struct nfs4_xattr_cache {
> + struct kref ref;
> + spinlock_t hash_lock; /* protects hashtable and lru */
> + struct nfs4_xattr_bucket buckets[NFS4_XATTR_HASH_SIZE];
> + struct list_head lru;
> + struct list_head dispose;
> + atomic_long_t nent;
> + spinlock_t listxattr_lock;
> + struct inode *inode;
> + struct nfs4_xattr_entry *listxattr;
> + struct work_struct work;
> +};
> +
> +struct nfs4_xattr_entry {
> + struct kref ref;
> + struct hlist_node hnode;
> + struct list_head lru;
> + struct list_head dispose;
> + char *xattr_name;
> + void *xattr_value;
> + size_t xattr_size;
> + struct nfs4_xattr_bucket *bucket;
> + uint32_t flags;
> +};
> +
> +#define NFS4_XATTR_ENTRY_EXTVAL 0x0001
> +
> +/*
> + * LRU list of NFS inodes that have xattr caches.
> + */
> +static struct list_lru nfs4_xattr_cache_lru;
> +static struct list_lru nfs4_xattr_entry_lru;
> +static struct list_lru nfs4_xattr_large_entry_lru;
> +
> +static struct kmem_cache *nfs4_xattr_cache_cachep;
> +
> +static struct workqueue_struct *nfs4_xattr_cache_wq;
> +
> +/*
> + * Hashing helper functions.
> + */
> +static void
> +nfs4_xattr_hash_init(struct nfs4_xattr_cache *cache)
> +{
> + unsigned int i;
> +
> + for (i = 0; i < NFS4_XATTR_HASH_SIZE; i++) {
> + INIT_HLIST_HEAD(&cache->buckets[i].hlist);
> + spin_lock_init(&cache->buckets[i].lock);
> + cache->buckets[i].cache = cache;
> + cache->buckets[i].draining = false;
> + }
> +}
> +
> +/*
> + * Locking order:
> + * 1. inode i_lock or bucket lock
> + * 2. list_lru lock (taken by list_lru_* functions)
> + */
> +
> +/*
> + * Wrapper functions to add a cache entry to the right LRU.
> + */
> +static bool
> +nfs4_xattr_entry_lru_add(struct nfs4_xattr_entry *entry)
> +{
> + struct list_lru *lru;
> +
> + lru = (entry->flags & NFS4_XATTR_ENTRY_EXTVAL) ?
> + &nfs4_xattr_large_entry_lru : &nfs4_xattr_entry_lru;
> +
> + return list_lru_add(lru, &entry->lru);
> +}
> +
> +static bool
> +nfs4_xattr_entry_lru_del(struct nfs4_xattr_entry *entry)
> +{
> + struct list_lru *lru;
> +
> + lru = (entry->flags & NFS4_XATTR_ENTRY_EXTVAL) ?
> + &nfs4_xattr_large_entry_lru : &nfs4_xattr_entry_lru;
> +
> + return list_lru_del(lru, &entry->lru);
> +}
> +
> +/*
> + * This function allocates cache entries. They are the normal
> + * extended attribute name/value pairs, but may also be a listxattr
> + * cache. Those allocations use the same entry so that they can be
> + * treated as one by the memory shrinker.
> + *
> + * xattr cache entries are allocated together with names. If the
> + * value fits in to one page with the entry structure and the name,
> + * it will also be part of the same allocation (kmalloc). This is
> + * expected to be the vast majority of cases. Larger allocations
> + * have a value pointer that is allocated separately by kvmalloc.
> + *
> + * Parameters:
> + *
> + * @name: Name of the extended attribute. NULL for listxattr cache
> + * entry.
> + * @value: Value of attribute, or listxattr cache. NULL if the
> + * value is to be copied from pages instead.
> + * @pages: Pages to copy the value from, if not NULL. Passed in to
> + * make it easier to copy the value after an RPC, even if
> + * the value will not be passed up to application (e.g.
> + * for a 'query' getxattr with NULL buffer).
> + * @len: Length of the value. Can be 0 for zero-length attribues.
> + * @value and @pages will be NULL if @len is 0.
> + */
> +static struct nfs4_xattr_entry *
> +nfs4_xattr_alloc_entry(const char *name, const void *value,
> + struct page **pages, size_t len)
> +{
> + struct nfs4_xattr_entry *entry;
> + void *valp;
> + char *namep;
> + size_t alloclen, slen;
> + char *buf;
> + uint32_t flags;
> +
> + BUILD_BUG_ON(sizeof(struct nfs4_xattr_entry) +
> + XATTR_NAME_MAX + 1 > PAGE_SIZE);
> +
> + alloclen = sizeof(struct nfs4_xattr_entry);
> + if (name != NULL) {
> + slen = strlen(name) + 1;
> + alloclen += slen;
> + } else
> + slen = 0;
> +
> + if (alloclen + len <= PAGE_SIZE) {
> + alloclen += len;
> + flags = 0;
> + } else {
> + flags = NFS4_XATTR_ENTRY_EXTVAL;
> + }
> +
> + buf = kmalloc(alloclen, GFP_KERNEL_ACCOUNT | GFP_NOFS);
> + if (buf == NULL)
> + return NULL;
> + entry = (struct nfs4_xattr_entry *)buf;
> +
> + if (name != NULL) {
> + namep = buf + sizeof(struct nfs4_xattr_entry);
> + memcpy(namep, name, slen);
> + } else {
> + namep = NULL;
> + }
> +
> +
> + if (flags & NFS4_XATTR_ENTRY_EXTVAL) {
> + valp = kvmalloc(len, GFP_KERNEL_ACCOUNT | GFP_NOFS);
> + if (valp == NULL) {
> + kfree(buf);
> + return NULL;
> + }
> + } else if (len != 0) {
> + valp = buf + sizeof(struct nfs4_xattr_entry) + slen;
> + } else
> + valp = NULL;
> +
> + if (valp != NULL) {
> + if (value != NULL)
> + memcpy(valp, value, len);
> + else
> + _copy_from_pages(valp, pages, 0, len);
> + }
> +
> + entry->flags = flags;
> + entry->xattr_value = valp;
> + kref_init(&entry->ref);
> + entry->xattr_name = namep;
> + entry->xattr_size = len;
> + entry->bucket = NULL;
> + INIT_LIST_HEAD(&entry->lru);
> + INIT_LIST_HEAD(&entry->dispose);
> + INIT_HLIST_NODE(&entry->hnode);
> +
> + return entry;
> +}
> +
> +static void
> +nfs4_xattr_free_entry(struct nfs4_xattr_entry *entry)
> +{
> + if (entry->flags & NFS4_XATTR_ENTRY_EXTVAL)
> + kvfree(entry->xattr_value);
> + kfree(entry);
> +}
> +
> +static void
> +nfs4_xattr_free_entry_cb(struct kref *kref)
> +{
> + struct nfs4_xattr_entry *entry;
> +
> + entry = container_of(kref, struct nfs4_xattr_entry, ref);
> +
> + if (WARN_ON(!list_empty(&entry->lru)))
> + return;
> +
> + nfs4_xattr_free_entry(entry);
> +}
> +
> +static void
> +nfs4_xattr_free_cache_cb(struct kref *kref)
> +{
> + struct nfs4_xattr_cache *cache;
> + int i;
> +
> + cache = container_of(kref, struct nfs4_xattr_cache, ref);
> +
> + for (i = 0; i < NFS4_XATTR_HASH_SIZE; i++) {
> + if (WARN_ON(!hlist_empty(&cache->buckets[i].hlist)))
> + return;
> + cache->buckets[i].draining = false;
> + }
> +
> + cache->listxattr = NULL;
> +
> + kmem_cache_free(nfs4_xattr_cache_cachep, cache);
> +
> +}
> +
> +static struct nfs4_xattr_cache *
> +nfs4_xattr_alloc_cache(void)
> +{
> + struct nfs4_xattr_cache *cache;
> +
> + cache = kmem_cache_alloc(nfs4_xattr_cache_cachep,
> + GFP_KERNEL_ACCOUNT | GFP_NOFS);
> + if (cache == NULL)
> + return NULL;
> +
> + kref_init(&cache->ref);
> + atomic_long_set(&cache->nent, 0);
> +
> + return cache;
> +}
> +
> +/*
> + * Set the listxattr cache, which is a special-cased cache entry.
> + * The special value ERR_PTR(-ESTALE) is used to indicate that
> + * the cache is being drained - this prevents a new listxattr
> + * cache from being added to what is now a stale cache.
> + */
> +static int
> +nfs4_xattr_set_listcache(struct nfs4_xattr_cache *cache,
> + struct nfs4_xattr_entry *new)
> +{
> + struct nfs4_xattr_entry *old;
> + int ret = 1;
> +
> + spin_lock(&cache->listxattr_lock);
> +
> + old = cache->listxattr;
> +
> + if (old == ERR_PTR(-ESTALE)) {
> + ret = 0;
> + goto out;
> + }
> +
> + cache->listxattr = new;
> + if (new != NULL && new != ERR_PTR(-ESTALE))
> + nfs4_xattr_entry_lru_add(new);
> +
> + if (old != NULL) {
> + nfs4_xattr_entry_lru_del(old);
> + kref_put(&old->ref, nfs4_xattr_free_entry_cb);
> + }
> +out:
> + spin_unlock(&cache->listxattr_lock);
> +
> + return ret;
> +}
> +
> +/*
> + * Unlink a cache from its parent inode, clearing out an invalid
> + * cache. Must be called with i_lock held.
> + */
> +static struct nfs4_xattr_cache *
> +nfs4_xattr_cache_unlink(struct inode *inode)
> +{
> + struct nfs_inode *nfsi;
> + struct nfs4_xattr_cache *oldcache;
> +
> + nfsi = NFS_I(inode);
> +
> + oldcache = nfsi->xattr_cache;
> + if (oldcache != NULL) {
> + list_lru_del(&nfs4_xattr_cache_lru, &oldcache->lru);
> + oldcache->inode = NULL;
> + }
> + nfsi->xattr_cache = NULL;
> + nfsi->cache_validity &= ~NFS_INO_INVALID_XATTR;
> +
> + return oldcache;
> +
> +}
> +
> +/*
> + * Discard a cache. Usually called by a worker, since walking all
> + * the entries can take up some cycles that we don't want to waste
> + * in the I/O path. Can also be called from the shrinker callback.
> + *
> + * The cache is dead, it has already been unlinked from its inode,
> + * and no longer appears on the cache LRU list.
> + *
> + * Mark all buckets as draining, so that no new entries are added. This
> + * could still happen in the unlikely, but possible case that another
> + * thread had grabbed a reference before it was unlinked from the inode,
> + * and is still holding it for an add operation.
> + *
> + * Remove all entries from the LRU lists, so that there is no longer
> + * any way to 'find' this cache. Then, remove the entries from the hash
> + * table.
> + *
> + * At that point, the cache will remain empty and can be freed when the final
> + * reference drops, which is very likely the kref_put at the end of
> + * this function, or the one called immediately afterwards in the
> + * shrinker callback.
> + */
> +static void
> +nfs4_xattr_discard_cache(struct nfs4_xattr_cache *cache)
> +{
> + unsigned int i;
> + struct nfs4_xattr_entry *entry;
> + struct nfs4_xattr_bucket *bucket;
> + struct hlist_node *n;
> +
> + nfs4_xattr_set_listcache(cache, ERR_PTR(-ESTALE));
> +
> + for (i = 0; i < NFS4_XATTR_HASH_SIZE; i++) {
> + bucket = &cache->buckets[i];
> +
> + spin_lock(&bucket->lock);
> + bucket->draining = true;
> + hlist_for_each_entry_safe(entry, n, &bucket->hlist, hnode) {
> + nfs4_xattr_entry_lru_del(entry);
> + hlist_del_init(&entry->hnode);
> + kref_put(&entry->ref, nfs4_xattr_free_entry_cb);
> + }
> + spin_unlock(&bucket->lock);
> + }
> +
> + atomic_long_set(&cache->nent, 0);
> +
> + kref_put(&cache->ref, nfs4_xattr_free_cache_cb);
> +}
> +
> +static void
> +nfs4_xattr_discard_cache_worker(struct work_struct *work)
> +{
> + struct nfs4_xattr_cache *cache = container_of(work,
> + struct nfs4_xattr_cache, work);
> +
> + nfs4_xattr_discard_cache(cache);
> +}
> +
> +static void
> +nfs4_xattr_reap_cache(struct nfs4_xattr_cache *cache)
> +{
> + queue_work(nfs4_xattr_cache_wq, &cache->work);
> +}
> +
> +/*
> + * Get a referenced copy of the cache structure. Avoid doing allocs
> + * while holding i_lock. Which means that we do some optimistic allocation,
> + * and might have to free the result in rare cases.
> + *
> + * This function only checks the NFS_INO_INVALID_XATTR cache validity bit
> + * and acts accordingly, replacing the cache when needed. For the read case
> + * (!add), this means that the caller must make sure that the cache
> + * is valid before caling this function. getxattr and listxattr call
> + * revalidate_inode to do this. The attribute cache timeout (for the
> + * non-delegated case) is expected to be dealt with in the revalidate
> + * call.
> + */
> +
> +static struct nfs4_xattr_cache *
> +nfs4_xattr_get_cache(struct inode *inode, int add)
> +{
> + struct nfs_inode *nfsi;
> + struct nfs4_xattr_cache *cache, *oldcache, *newcache;
> +
> + nfsi = NFS_I(inode);
> +
> + cache = oldcache = NULL;
> +
> + spin_lock(&inode->i_lock);
> +
> + if (nfsi->cache_validity & NFS_INO_INVALID_XATTR)
> + oldcache = nfs4_xattr_cache_unlink(inode);
> + else
> + cache = nfsi->xattr_cache;
> +
> + if (cache != NULL)
> + kref_get(&cache->ref);
> +
> + spin_unlock(&inode->i_lock);
> +
> + if (add && cache == NULL) {
> + newcache = NULL;
> +
> + cache = nfs4_xattr_alloc_cache();
> + if (cache == NULL)
> + goto out;
> +
> + spin_lock(&inode->i_lock);
> + if (nfsi->cache_validity & NFS_INO_INVALID_XATTR) {
> + /*
> + * The cache was invalidated again. Give up,
> + * since what we want to enter is now likely
> + * outdated anyway.
> + */
> + spin_unlock(&inode->i_lock);
> + kref_put(&cache->ref, nfs4_xattr_free_cache_cb);
> + cache = NULL;
> + goto out;
> + }
> +
> + /*
> + * Check if someone beat us to it.
> + */
> + if (nfsi->xattr_cache != NULL) {
> + newcache = nfsi->xattr_cache;
> + kref_get(&newcache->ref);
> + } else {
> + kref_get(&cache->ref);
> + nfsi->xattr_cache = cache;
> + cache->inode = inode;
> + list_lru_add(&nfs4_xattr_cache_lru, &cache->lru);
> + }
> +
> + spin_unlock(&inode->i_lock);
> +
> + /*
> + * If there was a race, throw away the cache we just
> + * allocated, and use the new one allocated by someone
> + * else.
> + */
> + if (newcache != NULL) {
> + kref_put(&cache->ref, nfs4_xattr_free_cache_cb);
> + cache = newcache;
> + }
> + }
> +
> +out:
> + /*
> + * Discarding an old cache is done via a workqueue.
> + */
> + if (oldcache != NULL)
> + nfs4_xattr_reap_cache(oldcache);
> +
> + return cache;
> +}
> +
> +static inline struct nfs4_xattr_bucket *
> +nfs4_xattr_hash_bucket(struct nfs4_xattr_cache *cache, const char *name)
> +{
> + return &cache->buckets[jhash(name, strlen(name), 0) &
> + (ARRAY_SIZE(cache->buckets) - 1)];
> +}
> +
> +static struct nfs4_xattr_entry *
> +nfs4_xattr_get_entry(struct nfs4_xattr_bucket *bucket, const char *name)
> +{
> + struct nfs4_xattr_entry *entry;
> +
> + entry = NULL;
> +
> + hlist_for_each_entry(entry, &bucket->hlist, hnode) {
> + if (!strcmp(entry->xattr_name, name))
> + break;
> + }
> +
> + return entry;
> +}
> +
> +static int
> +nfs4_xattr_hash_add(struct nfs4_xattr_cache *cache,
> + struct nfs4_xattr_entry *entry)
> +{
> + struct nfs4_xattr_bucket *bucket;
> + struct nfs4_xattr_entry *oldentry = NULL;
> + int ret = 1;
> +
> + bucket = nfs4_xattr_hash_bucket(cache, entry->xattr_name);
> + entry->bucket = bucket;
> +
> + spin_lock(&bucket->lock);
> +
> + if (bucket->draining) {
> + ret = 0;
> + goto out;
> + }
> +
> + oldentry = nfs4_xattr_get_entry(bucket, entry->xattr_name);
> + if (oldentry != NULL) {
> + hlist_del_init(&oldentry->hnode);
> + nfs4_xattr_entry_lru_del(oldentry);
> + } else {
> + atomic_long_inc(&cache->nent);
> + }
> +
> + hlist_add_head(&entry->hnode, &bucket->hlist);
> + nfs4_xattr_entry_lru_add(entry);
> +
> +out:
> + spin_unlock(&bucket->lock);
> +
> + if (oldentry != NULL)
> + kref_put(&oldentry->ref, nfs4_xattr_free_entry_cb);
> +
> + return ret;
> +}
> +
> +static void
> +nfs4_xattr_hash_remove(struct nfs4_xattr_cache *cache, const char *name)
> +{
> + struct nfs4_xattr_bucket *bucket;
> + struct nfs4_xattr_entry *entry;
> +
> + bucket = nfs4_xattr_hash_bucket(cache, name);
> +
> + spin_lock(&bucket->lock);
> +
> + entry = nfs4_xattr_get_entry(bucket, name);
> + if (entry != NULL) {
> + hlist_del_init(&entry->hnode);
> + nfs4_xattr_entry_lru_del(entry);
> + atomic_long_dec(&cache->nent);
> + }
> +
> + spin_unlock(&bucket->lock);
> +
> + if (entry != NULL)
> + kref_put(&entry->ref, nfs4_xattr_free_entry_cb);
> +}
> +
> +static struct nfs4_xattr_entry *
> +nfs4_xattr_hash_find(struct nfs4_xattr_cache *cache, const char *name)
> +{
> + struct nfs4_xattr_bucket *bucket;
> + struct nfs4_xattr_entry *entry;
> +
> + bucket = nfs4_xattr_hash_bucket(cache, name);
> +
> + spin_lock(&bucket->lock);
> +
> + entry = nfs4_xattr_get_entry(bucket, name);
> + if (entry != NULL)
> + kref_get(&entry->ref);
> +
> + spin_unlock(&bucket->lock);
> +
> + return entry;
> +}
> +
> +/*
> + * Entry point to retrieve an entry from the cache.
> + */
> +ssize_t nfs4_xattr_cache_get(struct inode *inode, const char *name, char
> *buf,
> + ssize_t buflen)
> +{
> + struct nfs4_xattr_cache *cache;
> + struct nfs4_xattr_entry *entry;
> + ssize_t ret;
> +
> + cache = nfs4_xattr_get_cache(inode, 0);
> + if (cache == NULL)
> + return -ENOENT;
> +
> + ret = 0;
> + entry = nfs4_xattr_hash_find(cache, name);
> +
> + if (entry != NULL) {
> + dprintk("%s: cache hit '%s', len %lu\n", __func__,
> + entry->xattr_name, (unsigned long)entry->xattr_size);
> + if (buflen == 0) {
> + /* Length probe only */
> + ret = entry->xattr_size;
> + } else if (buflen < entry->xattr_size)
> + ret = -ERANGE;
> + else {
> + memcpy(buf, entry->xattr_value, entry->xattr_size);
> + ret = entry->xattr_size;
> + }
> + kref_put(&entry->ref, nfs4_xattr_free_entry_cb);
> + } else {
> + dprintk("%s: cache miss '%s'\n", __func__, name);
> + ret = -ENOENT;
> + }
> +
> + kref_put(&cache->ref, nfs4_xattr_free_cache_cb);
> +
> + return ret;
> +}
> +
> +/*
> + * Retrieve a cached list of xattrs from the cache.
> + */
> +ssize_t nfs4_xattr_cache_list(struct inode *inode, char *buf, ssize_t buflen)
> +{
> + struct nfs4_xattr_cache *cache;
> + struct nfs4_xattr_entry *entry;
> + ssize_t ret;
> +
> + cache = nfs4_xattr_get_cache(inode, 0);
> + if (cache == NULL)
> + return -ENOENT;
> +
> + spin_lock(&cache->listxattr_lock);
> +
> + entry = cache->listxattr;
> +
> + if (entry != NULL && entry != ERR_PTR(-ESTALE)) {
> + if (buflen == 0) {
> + /* Length probe only */
> + ret = entry->xattr_size;
> + } else if (entry->xattr_size > buflen)
> + ret = -ERANGE;
> + else {
> + memcpy(buf, entry->xattr_value, entry->xattr_size);
> + ret = entry->xattr_size;
> + }
> + } else {
> + ret = -ENOENT;
> + }
> +
> + spin_unlock(&cache->listxattr_lock);
> +
> + kref_put(&cache->ref, nfs4_xattr_free_cache_cb);
> +
> + return ret;
> +}
> +
> +/*
> + * Add an xattr to the cache.
> + *
> + * This also invalidates the xattr list cache.
> + */
> +void nfs4_xattr_cache_add(struct inode *inode, const char *name,
> + const char *buf, struct page **pages, ssize_t buflen)
> +{
> + struct nfs4_xattr_cache *cache;
> + struct nfs4_xattr_entry *entry;
> +
> + dprintk("%s: add '%s' len %lu\n", __func__,
> + name, (unsigned long)buflen);
> +
> + cache = nfs4_xattr_get_cache(inode, 1);
> + if (cache == NULL)
> + return;
> +
> + entry = nfs4_xattr_alloc_entry(name, buf, pages, buflen);
> + if (entry == NULL)
> + goto out;
> +
> + (void)nfs4_xattr_set_listcache(cache, NULL);
> +
> + if (!nfs4_xattr_hash_add(cache, entry))
> + kref_put(&entry->ref, nfs4_xattr_free_entry_cb);
> +
> +out:
> + kref_put(&cache->ref, nfs4_xattr_free_cache_cb);
> +}
> +
> +
> +/*
> + * Remove an xattr from the cache.
> + *
> + * This also invalidates the xattr list cache.
> + */
> +void nfs4_xattr_cache_remove(struct inode *inode, const char *name)
> +{
> + struct nfs4_xattr_cache *cache;
> +
> + dprintk("%s: remove '%s'\n", __func__, name);
> +
> + cache = nfs4_xattr_get_cache(inode, 0);
> + if (cache == NULL)
> + return;
> +
> + (void)nfs4_xattr_set_listcache(cache, NULL);
> + nfs4_xattr_hash_remove(cache, name);
> +
> + kref_put(&cache->ref, nfs4_xattr_free_cache_cb);
> +}
> +
> +/*
> + * Cache listxattr output, replacing any possible old one.
> + */
> +void nfs4_xattr_cache_set_list(struct inode *inode, const char *buf,
> + ssize_t buflen)
> +{
> + struct nfs4_xattr_cache *cache;
> + struct nfs4_xattr_entry *entry;
> +
> + cache = nfs4_xattr_get_cache(inode, 1);
> + if (cache == NULL)
> + return;
> +
> + entry = nfs4_xattr_alloc_entry(NULL, buf, NULL, buflen);
> + if (entry == NULL)
> + goto out;
> +
> + /*
> + * This is just there to be able to get to bucket->cache,
> + * which is obviously the same for all buckets, so just
> + * use bucket 0.
> + */
> + entry->bucket = &cache->buckets[0];
> +
> + if (!nfs4_xattr_set_listcache(cache, entry))
> + kref_put(&entry->ref, nfs4_xattr_free_entry_cb);
> +
> +out:
> + kref_put(&cache->ref, nfs4_xattr_free_cache_cb);
> +}
> +
> +/*
> + * Zap the entire cache. Called when an inode is evicted.
> + */
> +void nfs4_xattr_cache_zap(struct inode *inode)
> +{
> + struct nfs4_xattr_cache *oldcache;
> +
> + spin_lock(&inode->i_lock);
> + oldcache = nfs4_xattr_cache_unlink(inode);
> + spin_unlock(&inode->i_lock);
> +
> + if (oldcache)
> + nfs4_xattr_discard_cache(oldcache);
> +}
> +
> +/*
> + * The entry LRU is shrunk more aggressively than the cache LRU,
> + * by settings @seeks to 1.
> + *
> + * Cache structures are freed only when they've become empty, after
> + * pruning all but one entry.
> + */
> +
> +static unsigned long nfs4_xattr_cache_count(struct shrinker *shrink,
> + struct shrink_control *sc);
> +static unsigned long nfs4_xattr_entry_count(struct shrinker *shrink,
> + struct shrink_control *sc);
> +static unsigned long nfs4_xattr_cache_scan(struct shrinker *shrink,
> + struct shrink_control *sc);
> +static unsigned long nfs4_xattr_entry_scan(struct shrinker *shrink,
> + struct shrink_control *sc);
> +
> +static struct shrinker nfs4_xattr_cache_shrinker = {
> + .count_objects = nfs4_xattr_cache_count,
> + .scan_objects = nfs4_xattr_cache_scan,
> + .seeks = DEFAULT_SEEKS,
> + .flags = SHRINKER_MEMCG_AWARE,
> +};
> +
> +static struct shrinker nfs4_xattr_entry_shrinker = {
> + .count_objects = nfs4_xattr_entry_count,
> + .scan_objects = nfs4_xattr_entry_scan,
> + .seeks = DEFAULT_SEEKS,
> + .batch = 512,
> + .flags = SHRINKER_MEMCG_AWARE,
> +};
> +
> +static struct shrinker nfs4_xattr_large_entry_shrinker = {
> + .count_objects = nfs4_xattr_entry_count,
> + .scan_objects = nfs4_xattr_entry_scan,
> + .seeks = 1,
> + .batch = 512,
> + .flags = SHRINKER_MEMCG_AWARE,
> +};
> +
> +static enum lru_status
> +cache_lru_isolate(struct list_head *item,
> + struct list_lru_one *lru, spinlock_t *lru_lock, void *arg)
> +{
> + struct list_head *dispose = arg;
> + struct inode *inode;
> + struct nfs4_xattr_cache *cache = container_of(item,
> + struct nfs4_xattr_cache, lru);
> +
> + if (atomic_long_read(&cache->nent) > 1)
> + return LRU_SKIP;
> +
> + /*
> + * If a cache structure is on the LRU list, we know that
> + * its inode is valid. Try to lock it to break the link.
> + * Since we're inverting the lock order here, only try.
> + */
> + inode = cache->inode;
> +
> + if (!spin_trylock(&inode->i_lock))
> + return LRU_SKIP;
> +
> + kref_get(&cache->ref);
> +
> + cache->inode = NULL;
> + NFS_I(inode)->xattr_cache = NULL;
> + NFS_I(inode)->cache_validity &= ~NFS_INO_INVALID_XATTR;
> + list_lru_isolate(lru, &cache->lru);
> +
> + spin_unlock(&inode->i_lock);
> +
> + list_add_tail(&cache->dispose, dispose);
> + return LRU_REMOVED;
> +}
> +
> +static unsigned long
> +nfs4_xattr_cache_scan(struct shrinker *shrink, struct shrink_control *sc)
> +{
> + LIST_HEAD(dispose);
> + unsigned long freed;
> + struct nfs4_xattr_cache *cache;
> +
> + freed = list_lru_shrink_walk(&nfs4_xattr_cache_lru, sc,
> + cache_lru_isolate, &dispose);
> + while (!list_empty(&dispose)) {
> + cache = list_first_entry(&dispose, struct nfs4_xattr_cache,
> + dispose);
> + list_del_init(&cache->dispose);
> + nfs4_xattr_discard_cache(cache);
> + kref_put(&cache->ref, nfs4_xattr_free_cache_cb);
> + }
> +
> + return freed;
> +}
> +
> +
> +static unsigned long
> +nfs4_xattr_cache_count(struct shrinker *shrink, struct shrink_control *sc)
> +{
> + unsigned long count;
> +
> + count = list_lru_count(&nfs4_xattr_cache_lru);
> + return vfs_pressure_ratio(count);
> +}
> +
> +static enum lru_status
> +entry_lru_isolate(struct list_head *item,
> + struct list_lru_one *lru, spinlock_t *lru_lock, void *arg)
> +{
> + struct list_head *dispose = arg;
> + struct nfs4_xattr_bucket *bucket;
> + struct nfs4_xattr_cache *cache;
> + struct nfs4_xattr_entry *entry = container_of(item,
> + struct nfs4_xattr_entry, lru);
> +
> + bucket = entry->bucket;
> + cache = bucket->cache;
> +
> + /*
> + * Unhook the entry from its parent (either a cache bucket
> + * or a cache structure if it's a listxattr buf), so that
> + * it's no longer found. Then add it to the isolate list,
> + * to be freed later.
> + *
> + * In both cases, we're reverting lock order, so use
> + * trylock and skip the entry if we can't get the lock.
> + */
> + if (entry->xattr_name != NULL) {
> + /* Regular cache entry */
> + if (!spin_trylock(&bucket->lock))
> + return LRU_SKIP;
> +
> + kref_get(&entry->ref);
> +
> + hlist_del_init(&entry->hnode);
> + atomic_long_dec(&cache->nent);
> + list_lru_isolate(lru, &entry->lru);
> +
> + spin_unlock(&bucket->lock);
> + } else {
> + /* Listxattr cache entry */
> + if (!spin_trylock(&cache->listxattr_lock))
> + return LRU_SKIP;
> +
> + kref_get(&entry->ref);
> +
> + cache->listxattr = NULL;
> + list_lru_isolate(lru, &entry->lru);
> +
> + spin_unlock(&cache->listxattr_lock);
> + }
> +
> + list_add_tail(&entry->dispose, dispose);
> + return LRU_REMOVED;
> +}
> +
> +static unsigned long
> +nfs4_xattr_entry_scan(struct shrinker *shrink, struct shrink_control *sc)
> +{
> + LIST_HEAD(dispose);
> + unsigned long freed;
> + struct nfs4_xattr_entry *entry;
> + struct list_lru *lru;
> +
> + lru = (shrink == &nfs4_xattr_large_entry_shrinker) ?
> + &nfs4_xattr_large_entry_lru : &nfs4_xattr_entry_lru;
> +
> + freed = list_lru_shrink_walk(lru, sc, entry_lru_isolate, &dispose);
> +
> + while (!list_empty(&dispose)) {
> + entry = list_first_entry(&dispose, struct nfs4_xattr_entry,
> + dispose);
> + list_del_init(&entry->dispose);
> +
> + /*
> + * Drop two references: the one that we just grabbed
> + * in entry_lru_isolate, and the one that was set
> + * when the entry was first allocated.
> + */
> + kref_put(&entry->ref, nfs4_xattr_free_entry_cb);
> + kref_put(&entry->ref, nfs4_xattr_free_entry_cb);
> + }
> +
> + return freed;
> +}
> +
> +static unsigned long
> +nfs4_xattr_entry_count(struct shrinker *shrink, struct shrink_control *sc)
> +{
> + unsigned long count;
> + struct list_lru *lru;
> +
> + lru = (shrink == &nfs4_xattr_large_entry_shrinker) ?
> + &nfs4_xattr_large_entry_lru : &nfs4_xattr_entry_lru;
> +
> + count = list_lru_count(lru);
> + return vfs_pressure_ratio(count);
> +}
> +
> +
> +static void nfs4_xattr_cache_init_once(void *p)
> +{
> + struct nfs4_xattr_cache *cache = (struct nfs4_xattr_cache *)p;
> +
> + spin_lock_init(&cache->listxattr_lock);
> + atomic_long_set(&cache->nent, 0);
> + nfs4_xattr_hash_init(cache);
> + cache->listxattr = NULL;
> + INIT_WORK(&cache->work, nfs4_xattr_discard_cache_worker);
> + INIT_LIST_HEAD(&cache->lru);
> + INIT_LIST_HEAD(&cache->dispose);
> +}
> +
> +int __init nfs4_xattr_cache_init(void)
> +{
> + int ret = 0;
> +
> + nfs4_xattr_cache_cachep = kmem_cache_create("nfs4_xattr_cache_cache",
> + sizeof(struct nfs4_xattr_cache), 0,
> + (SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD|SLAB_ACCOUNT),
> + nfs4_xattr_cache_init_once);
> + if (nfs4_xattr_cache_cachep == NULL)
> + return -ENOMEM;
> +
> + ret = list_lru_init_memcg(&nfs4_xattr_large_entry_lru,
> + &nfs4_xattr_large_entry_shrinker);
> + if (ret)
> + goto out4;
> +
> + ret = list_lru_init_memcg(&nfs4_xattr_entry_lru,
> + &nfs4_xattr_entry_shrinker);
> + if (ret)
> + goto out3;
> +
> + ret = list_lru_init_memcg(&nfs4_xattr_cache_lru,
> + &nfs4_xattr_cache_shrinker);
> + if (ret)
> + goto out2;
> +
> + nfs4_xattr_cache_wq = alloc_workqueue("nfs4_xattr", WQ_MEM_RECLAIM, 0);
> + if (nfs4_xattr_cache_wq == NULL)
> + goto out1;
> +
> + ret = register_shrinker(&nfs4_xattr_cache_shrinker);
> + if (ret)
> + goto out0;
> +
> + ret = register_shrinker(&nfs4_xattr_entry_shrinker);
> + if (ret)
> + goto out;
> +
> + ret = register_shrinker(&nfs4_xattr_large_entry_shrinker);
> + if (!ret)
> + return 0;
> +
> + unregister_shrinker(&nfs4_xattr_entry_shrinker);
> +out:
> + unregister_shrinker(&nfs4_xattr_cache_shrinker);
> +out0:
> + destroy_workqueue(nfs4_xattr_cache_wq);
> +out1:
> + list_lru_destroy(&nfs4_xattr_cache_lru);
> +out2:
> + list_lru_destroy(&nfs4_xattr_entry_lru);
> +out3:
> + list_lru_destroy(&nfs4_xattr_large_entry_lru);
> +out4:
> + kmem_cache_destroy(nfs4_xattr_cache_cachep);
> +
> + return ret;
> +}
> +
> +void nfs4_xattr_cache_exit(void)
> +{
> + unregister_shrinker(&nfs4_xattr_entry_shrinker);
> + unregister_shrinker(&nfs4_xattr_cache_shrinker);
> + list_lru_destroy(&nfs4_xattr_entry_lru);
> + list_lru_destroy(&nfs4_xattr_cache_lru);
> + kmem_cache_destroy(nfs4_xattr_cache_cachep);
> + destroy_workqueue(nfs4_xattr_cache_wq);
> +}
> diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
> index 6df94857f5bb..079c1ac84cee 100644
> --- a/fs/nfs/nfs4proc.c
> +++ b/fs/nfs/nfs4proc.c
> @@ -7459,6 +7459,7 @@ static int nfs4_xattr_set_nfs4_user(const struct
> xattr_handler *handler,
> size_t buflen, int flags)
> {
> struct nfs_access_entry cache;
> + int ret;
>
> if (!nfs_server_capable(inode, NFS_CAP_XATTR))
> return -EOPNOTSUPP;
> @@ -7477,10 +7478,17 @@ static int nfs4_xattr_set_nfs4_user(const struct
> xattr_handler *handler,
> return -EACCES;
> }
>
> - if (buf == NULL)
> - return nfs42_proc_removexattr(inode, key);
> - else
> - return nfs42_proc_setxattr(inode, key, buf, buflen, flags);
> + if (buf == NULL) {
> + ret = nfs42_proc_removexattr(inode, key);
> + if (!ret)
> + nfs4_xattr_cache_remove(inode, key);
> + } else {
> + ret = nfs42_proc_setxattr(inode, key, buf, buflen, flags);
> + if (!ret)
> + nfs4_xattr_cache_add(inode, key, buf, NULL, buflen);
> + }
> +
> + return ret;
> }
>
> static int nfs4_xattr_get_nfs4_user(const struct xattr_handler *handler,
> @@ -7488,6 +7496,7 @@ static int nfs4_xattr_get_nfs4_user(const struct
> xattr_handler *handler,
> const char *key, void *buf, size_t buflen)
> {
> struct nfs_access_entry cache;
> + ssize_t ret;
>
> if (!nfs_server_capable(inode, NFS_CAP_XATTR))
> return -EOPNOTSUPP;
> @@ -7497,7 +7506,17 @@ static int nfs4_xattr_get_nfs4_user(const struct
> xattr_handler *handler,
> return -EACCES;
> }
>
> - return nfs42_proc_getxattr(inode, key, buf, buflen);
> + ret = nfs_revalidate_inode(NFS_SERVER(inode), inode);
> + if (ret)
> + return ret;
> +
> + ret = nfs4_xattr_cache_get(inode, key, buf, buflen);
> + if (ret >= 0 || (ret < 0 && ret != -ENOENT))
> + return ret;
> +
> + ret = nfs42_proc_getxattr(inode, key, buf, buflen);
> +
> + return ret;
> }
>
> static ssize_t
> @@ -7505,7 +7524,7 @@ nfs4_listxattr_nfs4_user(struct inode *inode, char
> *list, size_t list_len)
> {
> u64 cookie;
> bool eof;
> - int ret, size;
> + ssize_t ret, size;
> char *buf;
> size_t buflen;
> struct nfs_access_entry cache;
> @@ -7518,6 +7537,14 @@ nfs4_listxattr_nfs4_user(struct inode *inode, char
> *list, size_t list_len)
> return 0;
> }
>
> + ret = nfs_revalidate_inode(NFS_SERVER(inode), inode);
> + if (ret)
> + return ret;
> +
> + ret = nfs4_xattr_cache_list(inode, list, list_len);
> + if (ret >= 0 || (ret < 0 && ret != -ENOENT))
> + return ret;
> +
> cookie = 0;
> eof = false;
> buflen = list_len ? list_len : XATTR_LIST_MAX;
> @@ -7537,6 +7564,9 @@ nfs4_listxattr_nfs4_user(struct inode *inode, char
> *list, size_t list_len)
> size += ret;
> }
>
> + if (list_len)
> + nfs4_xattr_cache_set_list(inode, list, size);
> +
> return size;
> }
>
> diff --git a/fs/nfs/nfs4super.c b/fs/nfs/nfs4super.c
> index 1475f932d7da..0c1ab846b83d 100644
> --- a/fs/nfs/nfs4super.c
> +++ b/fs/nfs/nfs4super.c
> @@ -69,6 +69,7 @@ static void nfs4_evict_inode(struct inode *inode)
> pnfs_destroy_layout(NFS_I(inode));
> /* First call standard NFS clear_inode() code */
> nfs_clear_inode(inode);
> + nfs4_xattr_cache_zap(inode);
> }
>
> struct nfs_referral_count {
> @@ -268,6 +269,12 @@ static int __init init_nfs_v4(void)
> if (err)
> goto out1;
>
> +#ifdef CONFIG_NFS_V4_2
> + err = nfs4_xattr_cache_init();
> + if (err)
> + goto out2;
> +#endif
> +
> err = nfs4_register_sysctl();
> if (err)
> goto out2;
> @@ -288,6 +295,9 @@ static void __exit exit_nfs_v4(void)
> nfs4_pnfs_v3_ds_connect_unload();
>
> unregister_nfs_version(&nfs_v4);
> +#ifdef CONFIG_NFS_V4_2
> + nfs4_xattr_cache_exit();
> +#endif
> nfs4_unregister_sysctl();
> nfs_idmap_quit();
> nfs_dns_resolver_destroy();
> diff --git a/include/linux/nfs_fs.h b/include/linux/nfs_fs.h
> index 1fcfef670a4a..c08cc22d9c32 100644
> --- a/include/linux/nfs_fs.h
> +++ b/include/linux/nfs_fs.h
> @@ -102,6 +102,8 @@ struct nfs_delegation;
>
> struct posix_acl;
>
> +struct nfs4_xattr_cache;
> +
> /*
> * nfs fs inode data in memory
> */
> @@ -188,6 +190,10 @@ struct nfs_inode {
> struct fscache_cookie *fscache;
> #endif
> struct inode vfs_inode;
> +
> +#ifdef CONFIG_NFS_V4_2
> + struct nfs4_xattr_cache *xattr_cache;
> +#endif
> };
>
> struct nfs4_copy_state {
> diff --git a/include/uapi/linux/nfs_fs.h b/include/uapi/linux/nfs_fs.h
> index 7bcc8cd6831d..3afe3767c55d 100644
> --- a/include/uapi/linux/nfs_fs.h
> +++ b/include/uapi/linux/nfs_fs.h
> @@ -56,6 +56,7 @@
> #define NFSDBG_PNFS 0x1000
> #define NFSDBG_PNFS_LD 0x2000
> #define NFSDBG_STATE 0x4000
> +#define NFSDBG_XATTRCACHE 0x8000
> #define NFSDBG_ALL 0xFFFF
>
>