Update Linux to v5.10.109
Sourced from [1]
[1] https://cdn.kernel.org/pub/linux/kernel/v5.x/linux-5.10.109.tar.xz
Change-Id: I19bca9fc6762d4e63bcf3e4cba88bbe560d9c76c
Signed-off-by: Olivier Deprez <olivier.deprez@arm.com>
diff --git a/fs/nfs/nfs42xattr.c b/fs/nfs/nfs42xattr.c
new file mode 100644
index 0000000..6c2ce79
--- /dev/null
+++ b/fs/nfs/nfs42xattr.c
@@ -0,0 +1,1057 @@
+// 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;
+ 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 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;
+
+/*
+ * 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. Called by get_cache() if there was an old,
+ * invalid cache. Can also be called from a 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);
+}
+
+/*
+ * 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:
+ /*
+ * Discard the now orphaned old cache.
+ */
+ if (oldcache != NULL)
+ nfs4_xattr_discard_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_shrink_count(&nfs4_xattr_cache_lru, sc);
+ 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_shrink_count(lru, sc);
+ 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_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;
+
+ ret = register_shrinker(&nfs4_xattr_cache_shrinker);
+ if (ret)
+ goto out1;
+
+ 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);
+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_large_entry_shrinker);
+ unregister_shrinker(&nfs4_xattr_entry_shrinker);
+ unregister_shrinker(&nfs4_xattr_cache_shrinker);
+ list_lru_destroy(&nfs4_xattr_large_entry_lru);
+ list_lru_destroy(&nfs4_xattr_entry_lru);
+ list_lru_destroy(&nfs4_xattr_cache_lru);
+ kmem_cache_destroy(nfs4_xattr_cache_cachep);
+}