mirror of
https://mirrors.bfsu.edu.cn/git/linux.git
synced 2024-12-15 06:55:13 +08:00
7e7ce2ccba
remove unnecessary void* type castings. Signed-off-by: yuzhe <yuzhe@nfschina.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
1058 lines
25 KiB
C
1058 lines
25 KiB
C
// 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 attributes.
|
|
* @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);
|
|
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);
|
|
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);
|
|
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 = 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),
|
|
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, "nfs-xattr_cache");
|
|
if (ret)
|
|
goto out1;
|
|
|
|
ret = register_shrinker(&nfs4_xattr_entry_shrinker, "nfs-xattr_entry");
|
|
if (ret)
|
|
goto out;
|
|
|
|
ret = register_shrinker(&nfs4_xattr_large_entry_shrinker,
|
|
"nfs-xattr_large_entry");
|
|
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);
|
|
}
|