// SPDX-License-Identifier: GPL-2.0
/*
* The NFSD open file cache.
*
* (c) 2015 - Jeff Layton <[email protected]>
*
* An nfsd_file object is a per-file collection of open state that binds
* together:
* - a struct file *
* - a user credential
* - a network namespace
* - a read-ahead context
* - monitoring for writeback errors
*
* nfsd_file objects are reference-counted. Consumers acquire a new
* object via the nfsd_file_acquire API. They manage their interest in
* the acquired object, and hence the object's reference count, via
* nfsd_file_get and nfsd_file_put. There are two varieties of nfsd_file
* object:
*
* * non-garbage-collected: When a consumer wants to precisely control
* the lifetime of a file's open state, it acquires a non-garbage-
* collected nfsd_file. The final nfsd_file_put releases the open
* state immediately.
*
* * garbage-collected: When a consumer does not control the lifetime
* of open state, it acquires a garbage-collected nfsd_file. The
* final nfsd_file_put allows the open state to linger for a period
* during which it may be re-used.
*/
#include <linux/hash.h>
#include <linux/slab.h>
#include <linux/file.h>
#include <linux/pagemap.h>
#include <linux/sched.h>
#include <linux/list_lru.h>
#include <linux/fsnotify_backend.h>
#include <linux/fsnotify.h>
#include <linux/seq_file.h>
#include <linux/rhashtable.h>
#include "vfs.h"
#include "nfsd.h"
#include "nfsfh.h"
#include "netns.h"
#include "filecache.h"
#include "trace.h"
#define NFSD_LAUNDRETTE_DELAY (2 * HZ)
#define NFSD_FILE_CACHE_UP (0)
/* We only care about NFSD_MAY_READ/WRITE for this cache */
#define NFSD_FILE_MAY_MASK (NFSD_MAY_READ|NFSD_MAY_WRITE|NFSD_MAY_LOCALIO)
static DEFINE_PER_CPU(unsigned long, nfsd_file_cache_hits);
static DEFINE_PER_CPU(unsigned long, nfsd_file_acquisitions);
static DEFINE_PER_CPU(unsigned long, nfsd_file_allocations);
static DEFINE_PER_CPU(unsigned long, nfsd_file_releases);
static DEFINE_PER_CPU(unsigned long, nfsd_file_total_age);
static DEFINE_PER_CPU(unsigned long, nfsd_file_evictions);
struct nfsd_fcache_disposal {
spinlock_t lock;
struct list_head freeme;
};
static struct kmem_cache *nfsd_file_slab;
static struct kmem_cache *nfsd_file_mark_slab;
static struct list_lru nfsd_file_lru;
static unsigned long nfsd_file_flags;
static struct fsnotify_group *nfsd_file_fsnotify_group;
static struct delayed_work nfsd_filecache_laundrette;
static struct rhltable nfsd_file_rhltable
____cacheline_aligned_in_smp;
static bool
nfsd_match_cred(const struct cred *c1, const struct cred *c2)
{
int i;
if (!uid_eq(c1->fsuid, c2->fsuid))
return false;
if (!gid_eq(c1->fsgid, c2->fsgid))
return false;
if (c1->group_info == NULL || c2->group_info == NULL)
return c1->group_info == c2->group_info;
if (c1->group_info->ngroups != c2->group_info->ngroups)
return false;
for (i = 0; i < c1->group_info->ngroups; i++) {
if (!gid_eq(c1->group_info->gid[i], c2->group_info->gid[i]))
return false;
}
return true;
}
static const struct rhashtable_params nfsd_file_rhash_params = {
.key_len = sizeof_field(struct nfsd_file, nf_inode),
.key_offset = offsetof(struct nfsd_file, nf_inode),
.head_offset = offsetof(struct nfsd_file, nf_rlist),
/*
* Start with a single page hash table to reduce resizing churn
* on light workloads.
*/
.min_size = 256,
.automatic_shrinking = true,
};
static void
nfsd_file_schedule_laundrette(void)
{
if (test_bit(NFSD_FILE_CACHE_UP, &nfsd_file_flags))
queue_delayed_work(system_unbound_wq, &nfsd_filecache_laundrette,
NFSD_LAUNDRETTE_DELAY);
}
static void
nfsd_file_slab_free(struct rcu_head *rcu)
{
struct nfsd_file *nf = container_of(rcu, struct nfsd_file, nf_rcu);
put_cred(nf->nf_cred);
kmem_cache_free(nfsd_file_slab, nf);
}
static void
nfsd_file_mark_free(struct fsnotify_mark *mark)
{
struct nfsd_file_mark *nfm = container_of(mark, struct nfsd_file_mark,
nfm_mark);
kmem_cache_free(nfsd_file_mark_slab, nfm);
}
static struct nfsd_file_mark *
nfsd_file_mark_get(struct nfsd_file_mark *nfm)
{
if (!refcount_inc_not_zero(&nfm->nfm_ref))
return NULL;
return nfm;
}
static void
nfsd_file_mark_put(struct nfsd_file_mark *nfm)
{
if (refcount_dec_and_test(&nfm->nfm_ref)) {
fsnotify_destroy_mark(&nfm->nfm_mark, nfsd_file_fsnotify_group);
fsnotify_put_mark(&nfm->nfm_mark);
}
}
static struct nfsd_file_mark *
nfsd_file_mark_find_or_create(struct inode *inode)
{
int err;
struct fsnotify_mark *mark;
struct nfsd_file_mark *nfm = NULL, *new;
do {
fsnotify_group_lock(nfsd_file_fsnotify_group);
mark = fsnotify_find_inode_mark(inode,
nfsd_file_fsnotify_group);
if (mark) {
nfm = nfsd_file_mark_get(container_of(mark,
struct nfsd_file_mark,
nfm_mark));
fsnotify_group_unlock(nfsd_file_fsnotify_group);
if (nfm) {
fsnotify_put_mark(mark);
break;
}
/* Avoid soft lockup race with nfsd_file_mark_put() */
fsnotify_destroy_mark(mark, nfsd_file_fsnotify_group);
fsnotify_put_mark(mark);
} else {
fsnotify_group_unlock(nfsd_file_fsnotify_group);
}
/* allocate a new nfm */
new = kmem_cache_alloc(nfsd_file_mark_slab, GFP_KERNEL);
if (!new)
return NULL;
fsnotify_init_mark(&new->nfm_mark, nfsd_file_fsnotify_group);
new->nfm_mark.mask = FS_ATTRIB|FS_DELETE_SELF;
refcount_set(&new->nfm_ref, 1);
err = fsnotify_add_inode_mark(&new->nfm_mark, inode, 0);
/*
* If the add was successful, then return the object.
* Otherwise, we need to put the reference we hold on the
* nfm_mark. The fsnotify code will take a reference and put
* it on failure, so we can't just free it directly. It's also
* not safe to call fsnotify_destroy_mark on it as the
* mark->group will be NULL. Thus, we can't let the nfm_ref
* counter drive the destruction at this point.
*/
if (likely(!err))
nfm = new;
else
fsnotify_put_mark(&new->nfm_mark);
} while (unlikely(err == -EEXIST));
return nfm;
}
static struct nfsd_file *
nfsd_file_alloc(struct net *net, struct inode *inode, unsigned char need,
bool want_gc)
{
struct nfsd_file *nf;
nf = kmem_cache_alloc(nfsd_file_slab, GFP_KERNEL);
if (unlikely(!nf))
return NULL;
this_cpu_inc(nfsd_file_allocations);
INIT_LIST_HEAD(&nf->nf_lru);
INIT_LIST_HEAD(&nf->nf_gc);
nf->nf_birthtime = ktime_get();
nf->nf_file = NULL;
nf->nf_cred = get_current_cred();
nf->nf_net = net;
nf->nf_flags = want_gc ?
BIT(NFSD_FILE_HASHED) | BIT(NFSD_FILE_PENDING) | BIT(NFSD_FILE_GC) :
BIT(NFSD_FILE_HASHED) | BIT(NFSD_FILE_PENDING);
nf->nf_inode = inode;
refcount_set(&nf->nf_ref, 1);
nf->nf_may = need;
nf->nf_mark = NULL;
return nf;
}
/**
* nfsd_file_check_write_error - check for writeback errors on a file
* @nf: nfsd_file to check for writeback errors
*
* Check whether a nfsd_file has an unseen error. Reset the write
* verifier if so.
*/
static void
nfsd_file_check_write_error(struct nfsd_file *nf)
{
struct file *file = nf->nf_file;
if ((file->f_mode & FMODE_WRITE) &&
filemap_check_wb_err(file->f_mapping, READ_ONCE(file->f_wb_err)))
nfsd_reset_write_verifier(net_generic(nf->nf_net, nfsd_net_id));
}
static void
nfsd_file_hash_remove(struct nfsd_file *nf)
{
trace_nfsd_file_unhash(nf);
rhltable_remove(&nfsd_file_rhltable, &nf->nf_rlist,
nfsd_file_rhash_params);
}
static bool
nfsd_file_unhash(struct nfsd_file *nf)
{
if (test_and_clear_bit(NFSD_FILE_HASHED, &nf->nf_flags)) {
nfsd_file_hash_remove(nf);
return true;
}
return false;
}
static void
nfsd_file_free(struct nfsd_file *nf)
{
s64 age = ktime_to_ms(ktime_sub(ktime_get(), nf->nf_birthtime));
trace_nfsd_file_free(nf);
this_cpu_inc(nfsd_file_releases);
this_cpu_add(nfsd_file_total_age, age);
nfsd_file_unhash(nf);
if (nf->nf_mark)
nfsd_file_mark_put(nf->nf_mark);
if (nf->nf_file) {
nfsd_file_check_write_error(nf);
nfsd_filp_close(nf->nf_file);
}
/*
* If this item is still linked via nf_lru, that's a bug.
* WARN and leak it to preserve system stability.
*/
if (WARN_ON_ONCE(!list_empty(&nf->nf_lru)))
return;
call_rcu(&nf->nf_rcu, nfsd_file_slab_free);
}
static bool
nfsd_file_check_writeback(struct nfsd_file *nf)
{
struct file *file = nf->nf_file;
struct address_space *mapping;
/* File not open for write? */
if (!(file->f_mode & FMODE_WRITE))
return false;
/*
* Some filesystems (e.g. NFS) flush all dirty data on close.
* On others, there is no need to wait for writeback.
*/
if (!(file_inode(file)->i_sb->s_export_op->flags & EXPORT_OP_FLUSH_ON_CLOSE))
return false;
mapping = file->f_mapping;
return mapping_tagged(mapping, PAGECACHE_TAG_DIRTY) ||
mapping_tagged(mapping, PAGECACHE_TAG_WRITEBACK);
}
static bool nfsd_file_lru_add(struct nfsd_file *nf)
{
set_bit(NFSD_FILE_REFERENCED, &nf->nf_flags);
if (list_lru_add_obj(&nfsd_file_lru, &nf->nf_lru)) {
trace_nfsd_file_lru_add(nf);
return true;
}
return false;
}
static bool nfsd_file_lru_remove(struct nfsd_file *nf)
{
if (list_lru_del_obj(&nfsd_file_lru, &nf->nf_lru)) {
trace_nfsd_file_lru_del(nf);
return true;
}
return false;
}
struct nfsd_file *
nfsd_file_get(struct nfsd_file *nf)
{
if (nf && refcount_inc_not_zero(&nf->nf_ref))
return nf;
return NULL;
}
/**
* nfsd_file_put - put the reference to a nfsd_file
* @nf: nfsd_file of which to put the reference
*
* Put a reference to a nfsd_file. In the non-GC case, we just put the
* reference immediately. In the GC case, if the reference would be
* the last one, the put it on the LRU instead to be cleaned up later.
*/
void
nfsd_file_put(struct nfsd_file *nf)
{
might_sleep();
trace_nfsd_file_put(nf);
if (test_bit(NFSD_FILE_GC, &nf->nf_flags) &&
test_bit(NFSD_FILE_HASHED, &nf->nf_flags)) {
/*
* If this is the last reference (nf_ref == 1), then try to
* transfer it to the LRU.
*/
if (refcount_dec_not_one(&nf->nf_ref))
return;
/* Try to add it to the LRU. If that fails, decrement. */
if (nfsd_file_lru_add(nf)) {
/* If it's still hashed, we're done */
if (test_bit(NFSD_FILE_HASHED, &nf->nf_flags)) {
nfsd_file_schedule_laundrette();
return;
}
/*
* We're racing with unhashing, so try to remove it from
* the LRU. If removal fails, then someone else already
* has our reference.
*/
if (!nfsd_file_lru_remove(nf))
return;
}
}
if (refcount_dec_and_test(&nf->nf_ref))
nfsd_file_free(nf);
}
/**
* nfsd_file_put_local - put the reference to nfsd_file and local nfsd_serv
* @nf: nfsd_file of which to put the references
*
* First put the reference of the nfsd_file and then put the
* reference to the associated nn->nfsd_serv.
*/
void
nfsd_file_put_local(struct nfsd_file *nf)
{
struct net *net = nf->nf_net;
nfsd_file_put(nf);
nfsd_serv_put(net);
}
/**
* nfsd_file_file - get the backing file of an nfsd_file
* @nf: nfsd_file of which to access the backing file.
*
* Return backing file for @nf.
*/
struct file *
nfsd_file_file(struct nfsd_file *nf)
{
return nf->nf_file;
}
static void
nfsd_file_dispose_list(struct list_head *dispose)
{
struct nfsd_file *nf;
while (!list_empty(dispose)) {
nf = list_first_entry(dispose, struct nfsd_file, nf_gc);
list_del_init(&nf->nf_gc);
nfsd_file_free(nf);
}
}
/**
* nfsd_file_dispose_list_delayed - move list of dead files to net's freeme list
* @dispose: list of nfsd_files to be disposed
*
* Transfers each file to the "freeme" list for its nfsd_net, to eventually
* be disposed of by the per-net garbage collector.
*/
static void
nfsd_file_dispose_list_delayed(struct list_head *dispose)
{
while(!list_empty(dispose)) {
struct nfsd_file *nf = list_first_entry(dispose,
struct nfsd_file, nf_gc);
struct nfsd_net *nn = net_generic(nf->nf_net, nfsd_net_id);
struct nfsd_fcache_disposal *l = nn->fcache_disposal;
spin_lock(&l->lock);
list_move_tail(&nf->nf_gc, &l->freeme);
spin_unlock(&l->lock);
svc_wake_up(nn->nfsd_serv);
}
}
/**
* nfsd_file_net_dispose - deal with nfsd_files waiting to be disposed.
* @nn: nfsd_net in which to find files to be disposed.
*
* When files held open for nfsv3 are removed from the filecache, whether
* due to memory pressure or garbage collection, they are queued to
* a per-net-ns queue. This function completes the disposal, either
* directly or by waking another nfsd thread to help with the work.
*/
void nfsd_file_net_dispose(struct nfsd_net *nn)
{
struct nfsd_fcache_disposal *l = nn->fcache_disposal;
if (!list_empty(&l->freeme)) {
LIST_HEAD(dispose);
int i;
spin_lock(&l->lock);
for (i = 0; i < 8 && !list_empty(&l->freeme); i++)
list_move(l->freeme.next, &dispose);
spin_unlock(&l->lock);
if (!list_empty(&l->freeme))
/* Wake up another thread to share the work
* *before* doing any actual disposing.
*/
svc_wake_up(nn->nfsd_serv);
nfsd_file_dispose_list(&dispose);
}
}
/**
* nfsd_file_lru_cb - Examine an entry on the LRU list
* @item: LRU entry to examine
* @lru: controlling LRU
* @lock: LRU list lock (unused)
* @arg: dispose list
*
* Return values:
* %LRU_REMOVED: @item was removed from the LRU
* %LRU_ROTATE: @item is to be moved to the LRU tail
* %LRU_SKIP: @item cannot be evicted
*/
static enum lru_status
nfsd_file_lru_cb(struct list_head *item, struct list_lru_one *lru,
spinlock_t *lock, void *arg)
__releases(lock)
__acquires(lock)
{
struct list_head *head = arg;
struct nfsd_file *nf = list_entry(item, struct nfsd_file, nf_lru);
/* We should only be dealing with GC entries here */
WARN_ON_ONCE(!test_bit(NFSD_FILE_GC, &nf->nf_flags));
/*
* Don't throw out files that are still undergoing I/O or
* that have uncleared errors pending.
*/
if (nfsd_file_check_writeback(nf)) {
trace_nfsd_file_gc_writeback(nf);
return LRU_SKIP;
}
/* If it was recently added to the list, skip it */
if (test_and_clear_bit(NFSD_FILE_REFERENCED, &nf->nf_flags)) {
trace_nfsd_file_gc_referenced(nf);
return LRU_ROTATE;
}
/*
* Put the reference held on behalf of the LRU. If it wasn't the last
* one, then just remove it from the LRU and ignore it.
*/
if (!refcount_dec_and_test(&nf->nf_ref)) {
trace_nfsd_file_gc_in_use(nf);
list_lru_isolate(lru, &nf->nf_lru);
return LRU_REMOVED;
}
/* Refcount went to zero. Unhash it and queue it to the dispose list */
nfsd_file_unhash(nf);
list_lru_isolate(lru, &nf->nf_lru);
list_add(&nf->nf_gc, head);
this_cpu_inc(nfsd_file_evictions);
trace_nfsd_file_gc_disposed(nf);
return LRU_REMOVED;
}
static void
nfsd_file_gc(void)
{
LIST_HEAD(dispose);
unsigned long ret;
ret = list_lru_walk(&nfsd_file_lru, nfsd_file_lru_cb,
&dispose, list_lru_count(&nfsd_file_lru));
trace_nfsd_file_gc_removed(ret, list_lru_count(&nfsd_file_lru));
nfsd_file_dispose_list_delayed(&dispose);
}
static void
nfsd_file_gc_worker(struct work_struct *work)
{
nfsd_file_gc();
if (list_lru_count(&nfsd_file_lru))
nfsd_file_schedule_laundrette();
}
static unsigned long
nfsd_file_lru_count(struct shrinker *s, struct shrink_control *sc)
{
return list_lru_count(&nfsd_file_lru);
}
static unsigned long
nfsd_file_lru_scan(struct shrinker *s, struct shrink_control *sc)
{
LIST_HEAD(dispose);
unsigned long ret;
ret = list_lru_shrink_walk(&nfsd_file_lru, sc,
nfsd_file_lru_cb, &dispose);
trace_nfsd_file_shrinker_removed(ret, list_lru_count(&nfsd_file_lru));
nfsd_file_dispose_list_delayed(&dispose);
return ret;
}
static struct shrinker *nfsd_file_shrinker;
/**
* nfsd_file_cond_queue - conditionally unhash and queue a nfsd_file
* @nf: nfsd_file to attempt to queue
* @dispose: private list to queue successfully-put objects
*
* Unhash an nfsd_file, try to get a reference to it, and then put that
* reference. If it's the last reference, queue it to the dispose list.
*/
static void
nfsd_file_cond_queue(struct nfsd_file *nf, struct list_head *dispose)
__must_hold(RCU)
{
int decrement = 1;
/* If we raced with someone else unhashing, ignore it */
if (!nfsd_file_unhash(nf))
return;
/* If we can't get a reference, ignore it */
if (!nfsd_file_get(nf))
return;
/* Extra decrement if we remove from the LRU */
if (nfsd_file_lru_remove(nf))
++decrement;
/* If refcount goes to 0, then put on the dispose list */
if (refcount_sub_and_test(decrement, &nf->nf_ref)) {
list_add(&nf->nf_gc, dispose);
trace_nfsd_file_closing(nf);
}
}
/**
* nfsd_file_queue_for_close: try to close out any open nfsd_files for an inode
* @inode: inode on which to close out nfsd_files
* @dispose: list on which to gather nfsd_files to close out
*
* An nfsd_file represents a struct file being held open on behalf of nfsd.
* An open file however can block other activity (such as leases), or cause
* undesirable behavior (e.g. spurious silly-renames when reexporting NFS).
*
* This function is intended to find open nfsd_files when this sort of
* conflicting access occurs and then attempt to close those files out.
*
* Populates the dispose list with entries that have already had their
* refcounts go to zero. The actual free of an nfsd_file can be expensive,
* so we leave it up to the caller whether it wants to wait or not.
*/
static void
nfsd_file_queue_for_close(struct inode *inode, struct list_head *dispose)
{
struct rhlist_head *tmp, *list;
struct nfsd_file *nf;
rcu_read_lock();
list = rhltable_lookup(&nfsd_file_rhltable, &inode,
nfsd_file_rhash_params);
rhl_for_each_entry_rcu(nf, tmp, list, nf_rlist) {
if (!test_bit(NFSD_FILE_GC, &nf->nf_flags))
continue;
nfsd_file_cond_queue(nf, dispose);
}
rcu_read_unlock();
}
/**
* nfsd_file_close_inode - attempt a delayed close of a nfsd_file
* @inode: inode of the file to attempt to remove
*
* Close out any open nfsd_files that can be reaped for @inode. The
* actual freeing is deferred to the dispose_list_delayed infrastructure.
*
* This is used by the fsnotify callbacks and setlease notifier.
*/
static void
nfsd_file_close_inode(struct inode *inode)
{
LIST_HEAD(dispose);
nfsd_file_queue_for_close(inode, &dispose);
nfsd_file_dispose_list_delayed(&dispose);
}
/**
* nfsd_file_close_inode_sync - attempt to forcibly close a nfsd_file
* @inode: inode of the file to attempt to remove
*
* Close out any open nfsd_files that can be reaped for @inode. The
* nfsd_files are closed out synchronously.
*
* This is called from nfsd_rename and nfsd_unlink to avoid silly-renames
* when reexporting NFS.
*/
void
nfsd_file_close_inode_sync(struct inode *inode)
{
struct nfsd_file *nf;
LIST_HEAD(dispose);
trace_nfsd_file_close(inode);
nfsd_file_queue_for_close(inode, &dispose);
while (!list_empty(&dispose)) {
nf = list_first_entry(&dispose, struct nfsd_file, nf_gc);
list_del_init(&nf->nf_gc);
nfsd_file_free(nf);
}
}
static int
nfsd_file_lease_notifier_call(struct notifier_block *nb, unsigned long arg,
void *data)
{
struct file_lease *fl = data;
/* Only close files for F_SETLEASE leases */
if (fl->c.flc_flags & FL_LEASE)
nfsd_file_close_inode(file_inode(fl->c.flc_file));
return 0;
}
static struct notifier_block nfsd_file_lease_notifier = {
.notifier_call = nfsd_file_lease_notifier_call,
};
static int
nfsd_file_fsnotify_handle_event(struct fsnotify_mark *mark, u32 mask,
struct inode *inode, struct inode *dir,
const struct qstr *name, u32 cookie)
{
if (WARN_ON_ONCE(!inode))
return 0;
trace_nfsd_file_fsnotify_handle_event(inode, mask);
/* Should be no marks on non-regular files */
if (!S_ISREG(inode->i_mode)) {
WARN_ON_ONCE(1);
return 0;
}
/* don't close files if this was not the last link */
if (mask & FS_ATTRIB) {
if (inode->i_nlink)
return 0;
}
nfsd_file_close_inode(inode);
return 0;
}
static const struct fsnotify_ops nfsd_file_fsnotify_ops = {
.handle_inode_event = nfsd_file_fsnotify_handle_event,
.free_mark = nfsd_file_mark_free,
};
int
nfsd_file_cache_init(void)
{
int ret;
lockdep_assert_held(&nfsd_mutex);
if (test_and_set_bit(NFSD_FILE_CACHE_UP, &nfsd_file_flags) == 1)
return 0;
ret = rhltable_init(&nfsd_file_rhltable, &nfsd_file_rhash_params);
if (ret)
return ret;
ret = -ENOMEM;
nfsd_file_slab = KMEM_CACHE(nfsd_file, 0);
if (!nfsd_file_slab) {
pr_err("nfsd: unable to create nfsd_file_slab\n");
goto out_err;
}
nfsd_file_mark_slab = KMEM_CACHE(nfsd_file_mark, 0);
if (!nfsd_file_mark_slab) {
pr_err("nfsd: unable to create nfsd_file_mark_slab\n");
goto out_err;
}
ret = list_lru_init(&nfsd_file_lru);
if (ret) {
pr_err("nfsd: failed to init nfsd_file_lru: %d\n", ret);
goto out_err;
}
nfsd_file_shrinker = shrinker_alloc(0, "nfsd-filecache");
if (!nfsd_file_shrinker) {
ret = -ENOMEM;
pr_err("nfsd: failed to allocate nfsd_file_shrinker\n");
goto out_lru;
}
nfsd_file_shrinker->count_objects = nfsd_file_lru_count;
nfsd_file_shrinker->scan_objects = nfsd_file_lru_scan;
nfsd_file_shrinker->seeks = 1;
shrinker_register(nfsd_file_shrinker);
ret = lease_register_notifier(&nfsd_file_lease_notifier);
if (ret) {
pr_err("nfsd: unable to register lease notifier: %d\n", ret);
goto out_shrinker;
}
nfsd_file_fsnotify_group = fsnotify_alloc_group(&nfsd_file_fsnotify_ops,
0);
if (IS_ERR(nfsd_file_fsnotify_group)) {
pr_err("nfsd: unable to create fsnotify group: %ld\n",
PTR_ERR(nfsd_file_fsnotify_group));
ret = PTR_ERR(nfsd_file_fsnotify_group);
nfsd_file_fsnotify_group = NULL;
goto out_notifier;
}
INIT_DELAYED_WORK(&nfsd_filecache_laundrette, nfsd_file_gc_worker);
out:
return ret;
out_notifier:
lease_unregister_notifier(&nfsd_file_lease_notifier);
out_shrinker:
shrinker_free(nfsd_file_shrinker);
out_lru:
list_lru_destroy(&nfsd_file_lru);
out_err:
kmem_cache_destroy(nfsd_file_slab);
nfsd_file_slab = NULL;
kmem_cache_destroy(nfsd_file_mark_slab);
nfsd_file_mark_slab = NULL;
rhltable_destroy(&nfsd_file_rhltable);
goto out;
}
/**
* __nfsd_file_cache_purge: clean out the cache for shutdown
* @net: net-namespace to shut down the cache (may be NULL)
*
* Walk the nfsd_file cache and close out any that match @net. If @net is NULL,
* then close out everything. Called when an nfsd instance is being shut down,
* and when the exports table is flushed.
*/
static void
__nfsd_file_cache_purge(struct net *net)
{
struct rhashtable_iter iter;
struct nfsd_file *nf;
LIST_HEAD(dispose);
rhltable_walk_enter(&nfsd_file_rhltable, &iter);
do {
rhashtable_walk_start(&iter);
nf = rhashtable_walk_next(&iter);
while (!IS_ERR_OR_NULL(nf)) {
if (!net || nf->nf_net == net)
nfsd_file_cond_queue(nf, &dispose);
nf = rhashtable_walk_next(&iter);
}
rhashtable_walk_stop(&iter);
} while (nf == ERR_PTR(-EAGAIN));
rhashtable_walk_exit(&iter);
nfsd_file_dispose_list(&dispose);
}
static struct nfsd_fcache_disposal *
nfsd_alloc_fcache_disposal(void)
{
struct nfsd_fcache_disposal *l;
l = kmalloc(sizeof(*l), GFP_KERNEL);
if (!l)
return NULL;
spin_lock_init(&l->lock);
INIT_LIST_HEAD(&l->freeme);
return l;
}
static void
nfsd_free_fcache_disposal(struct nfsd_fcache_disposal *l)
{
nfsd_file_dispose_list(&l->freeme);
kfree(l);
}
static void
nfsd_free_fcache_disposal_net(struct net *net)
{
struct nfsd_net *nn = net_generic(net, nfsd_net_id);
struct nfsd_fcache_disposal *l = nn->fcache_disposal;
nfsd_free_fcache_disposal(l);
}
int
nfsd_file_cache_start_net(struct net *net)
{
struct nfsd_net *nn = net_generic(net, nfsd_net_id);
nn->fcache_disposal = nfsd_alloc_fcache_disposal();
return nn->fcache_disposal ? 0 : -ENOMEM;
}
/**
* nfsd_file_cache_purge - Remove all cache items associated with @net
* @net: target net namespace
*
*/
void
nfsd_file_cache_purge(struct net *net)
{
lockdep_assert_held(&nfsd_mutex);
if (test_bit(NFSD_FILE_CACHE_UP, &nfsd_file_flags) == 1)
__nfsd_file_cache_purge(net);
}
void
nfsd_file_cache_shutdown_net(struct net *net)
{
nfsd_file_cache_purge(net);
nfsd_free_fcache_disposal_net(net);
}
void
nfsd_file_cache_shutdown(void)
{
int i;
lockdep_assert_held(&nfsd_mutex);
if (test_and_clear_bit(NFSD_FILE_CACHE_UP, &nfsd_file_flags) == 0)
return;
lease_unregister_notifier(&nfsd_file_lease_notifier);
shrinker_free(nfsd_file_shrinker);
/*
* make sure all callers of nfsd_file_lru_cb are done before
* calling nfsd_file_cache_purge
*/
cancel_delayed_work_sync(&nfsd_filecache_laundrette);
__nfsd_file_cache_purge(NULL);
list_lru_destroy(&nfsd_file_lru);
rcu_barrier();
fsnotify_put_group(nfsd_file_fsnotify_group);
nfsd_file_fsnotify_group = NULL;
kmem_cache_destroy(nfsd_file_slab);
nfsd_file_slab = NULL;
fsnotify_wait_marks_destroyed();
kmem_cache_destroy(nfsd_file_mark_slab);
nfsd_file_mark_slab = NULL;
rhltable_destroy(&nfsd_file_rhltable);
for_each_possible_cpu(i) {
per_cpu(nfsd_file_cache_hits, i) = 0;
per_cpu(nfsd_file_acquisitions, i) = 0;
per_cpu(nfsd_file_allocations, i) = 0;
per_cpu(nfsd_file_releases, i) = 0;
per_cpu(nfsd_file_total_age, i) = 0;
per_cpu(nfsd_file_evictions, i) = 0;
}
}
static struct nfsd_file *
nfsd_file_lookup_locked(const struct net *net, const struct cred *cred,
struct inode *inode, unsigned char need,
bool want_gc)
{
struct rhlist_head *tmp, *list;
struct nfsd_file *nf;
list = rhltable_lookup(&nfsd_file_rhltable, &inode,
nfsd_file_rhash_params);
rhl_for_each_entry_rcu(nf, tmp, list, nf_rlist) {
if (nf->nf_may != need)
continue;
if (nf->nf_net != net)
continue;
if (!nfsd_match_cred(nf->nf_cred, cred))
continue;
if (test_bit(NFSD_FILE_GC, &nf->nf_flags) != want_gc)
continue;
if (test_bit(NFSD_FILE_HASHED, &nf->nf_flags) == 0)
continue;
if (!nfsd_file_get(nf))
continue;
return nf;
}
return NULL;
}
/**
* nfsd_file_is_cached - are there any cached open files for this inode?
* @inode: inode to check
*
* The lookup matches inodes in all net namespaces and is atomic wrt
* nfsd_file_acquire().
*
* Return values:
* %true: filecache contains at least one file matching this inode
* %false: filecache contains no files matching this inode
*/
bool
nfsd_file_is_cached(struct inode *inode)
{
struct rhlist_head *tmp, *list;
struct nfsd_file *nf;
bool ret = false;
rcu_read_lock();
list = rhltable_lookup(&nfsd_file_rhltable, &inode,
nfsd_file_rhash_params);
rhl_for_each_entry_rcu(nf, tmp, list, nf_rlist)
if (test_bit(NFSD_FILE_GC, &nf->nf_flags)) {
ret = true;
break;
}
rcu_read_unlock();
trace_nfsd_file_is_cached(inode, (int)ret);
return ret;
}
static __be32
nfsd_file_do_acquire(struct svc_rqst *rqstp, struct net *net,
struct svc_cred *cred,
struct auth_domain *client,
struct svc_fh *fhp,
unsigned int may_flags, struct file *file,
struct nfsd_file **pnf, bool want_gc)
{
unsigned char need = may_flags & NFSD_FILE_MAY_MASK;
struct nfsd_file *new, *nf;
bool stale_retry = true;
bool open_retry = true;
struct inode *inode;
__be32 status;
int ret;
retry:
if (rqstp) {
status = fh_verify(rqstp, fhp, S_IFREG,
may_flags|NFSD_MAY_OWNER_OVERRIDE);
} else {
status = fh_verify_local(net, cred, client, fhp, S_IFREG,
may_flags|NFSD_MAY_OWNER_OVERRIDE);
}
if (status != nfs_ok)
return status;
inode = d_inode(fhp->fh_dentry);
rcu_read_lock();
nf = nfsd_file_lookup_locked(net, current_cred(), inode, need, want_gc);
rcu_read_unlock();
if (nf) {
/*
* If the nf is on the LRU then it holds an extra reference
* that must be put if it's removed. It had better not be
* the last one however, since we should hold another.
*/
if (nfsd_file_lru_remove(nf))
WARN_ON_ONCE(refcount_dec_and_test(&nf->nf_ref));
goto wait_for_construction;
}
new = nfsd_file_alloc(net, inode, need, want_gc);
if (!new) {
status = nfserr_jukebox;
goto out;
}
rcu_read_lock();
spin_lock(&inode->i_lock);
nf = nfsd_file_lookup_locked(net, current_cred(), inode, need, want_gc);
if (unlikely(nf)) {
spin_unlock(&inode->i_lock);
rcu_read_unlock();
nfsd_file_free(new);
goto wait_for_construction;
}
nf = new;
ret = rhltable_insert(&nfsd_file_rhltable, &nf->nf_rlist,
nfsd_file_rhash_params);
spin_unlock(&inode->i_lock);
rcu_read_unlock();
if (likely(ret == 0))
goto open_file;
trace_nfsd_file_insert_err(rqstp, inode, may_flags, ret);
status = nfserr_jukebox;
goto construction_err;
wait_for_construction:
wait_on_bit(&nf->nf_flags, NFSD_FILE_PENDING, TASK_UNINTERRUPTIBLE);
/* Did construction of this file fail? */
if (!test_bit(NFSD_FILE_HASHED, &nf->nf_flags)) {
trace_nfsd_file_cons_err(rqstp, inode, may_flags, nf);
if (!open_retry) {
status = nfserr_jukebox;
goto construction_err;
}
nfsd_file_put(nf);
open_retry = false;
fh_put(fhp);
goto retry;
}
this_cpu_inc(nfsd_file_cache_hits);
status = nfserrno(nfsd_open_break_lease(file_inode(nf->nf_file), may_flags));
if (status != nfs_ok) {
nfsd_file_put(nf);
nf = NULL;
}
out:
if (status == nfs_ok) {
this_cpu_inc(nfsd_file_acquisitions);
nfsd_file_check_write_error(nf);
*pnf = nf;
}
trace_nfsd_file_acquire(rqstp, inode, may_flags, nf, status);
return status;
open_file:
trace_nfsd_file_alloc(nf);
nf->nf_mark = nfsd_file_mark_find_or_create(inode);
if (nf->nf_mark) {
if (file) {
get_file(file);
nf->nf_file = file;
status = nfs_ok;
trace_nfsd_file_opened(nf, status);
} else {
ret = nfsd_open_verified(rqstp, fhp, may_flags,
&nf->nf_file);
if (ret == -EOPENSTALE && stale_retry) {
stale_retry = false;
nfsd_file_unhash(nf);
clear_and_wake_up_bit(NFSD_FILE_PENDING,
&nf->nf_flags);
if (refcount_dec_and_test(&nf->nf_ref))
nfsd_file_free(nf);
nf = NULL;
fh_put(fhp);
goto retry;
}
status = nfserrno(ret);
trace_nfsd_file_open(nf, status);
}
} else
status = nfserr_jukebox;
/*
* If construction failed, or we raced with a call to unlink()
* then unhash.
*/
if (status != nfs_ok || inode->i_nlink == 0)
nfsd_file_unhash(nf);
clear_and_wake_up_bit(NFSD_FILE_PENDING, &nf->nf_flags);
if (status == nfs_ok)
goto out;
construction_err:
if (refcount_dec_and_test(&nf->nf_ref))
nfsd_file_free(nf);
nf = NULL;
goto out;
}
/**
* nfsd_file_acquire_gc - Get a struct nfsd_file with an open file
* @rqstp: the RPC transaction being executed
* @fhp: the NFS filehandle of the file to be opened
* @may_flags: NFSD_MAY_ settings for the file
* @pnf: OUT: new or found "struct nfsd_file" object
*
* The nfsd_file object returned by this API is reference-counted
* and garbage-collected. The object is retained for a few
* seconds after the final nfsd_file_put() in case the caller
* wants to re-use it.
*
* Return values:
* %nfs_ok - @pnf points to an nfsd_file with its reference
* count boosted.
*
* On error, an nfsstat value in network byte order is returned.
*/
__be32
nfsd_file_acquire_gc(struct svc_rqst *rqstp, struct svc_fh *fhp,
unsigned int may_flags, struct nfsd_file **pnf)
{
return nfsd_file_do_acquire(rqstp, SVC_NET(rqstp), NULL, NULL,
fhp, may_flags, NULL, pnf, true);
}
/**
* nfsd_file_acquire - Get a struct nfsd_file with an open file
* @rqstp: the RPC transaction being executed
* @fhp: the NFS filehandle of the file to be opened
* @may_flags: NFSD_MAY_ settings for the file
* @pnf: OUT: new or found "struct nfsd_file" object
*
* The nfsd_file_object returned by this API is reference-counted
* but not garbage-collected. The object is unhashed after the
* final nfsd_file_put().
*
* Return values:
* %nfs_ok - @pnf points to an nfsd_file with its reference
* count boosted.
*
* On error, an nfsstat value in network byte order is returned.
*/
__be32
nfsd_file_acquire(struct svc_rqst *rqstp, struct svc_fh *fhp,
unsigned int may_flags, struct nfsd_file **pnf)
{
return nfsd_file_do_acquire(rqstp, SVC_NET(rqstp), NULL, NULL,
fhp, may_flags, NULL, pnf, false);
}
/**
* nfsd_file_acquire_local - Get a struct nfsd_file with an open file for localio
* @net: The network namespace in which to perform a lookup
* @cred: the user credential with which to validate access
* @client: the auth_domain for LOCALIO lookup
* @fhp: the NFS filehandle of the file to be opened
* @may_flags: NFSD_MAY_ settings for the file
* @pnf: OUT: new or found "struct nfsd_file" object
*
* This file lookup interface provide access to a file given the
* filehandle and credential. No connection-based authorisation
* is performed and in that way it is quite different to other
* file access mediated by nfsd. It allows a kernel module such as the NFS
* client to reach across network and filesystem namespaces to access
* a file. The security implications of this should be carefully
* considered before use.
*
* The nfsd_file object returned by this API is reference-counted
* and garbage-collected. The object is retained for a few
* seconds after the final nfsd_file_put() in case the caller
* wants to re-use it.
*
* Return values:
* %nfs_ok - @pnf points to an nfsd_file with its reference
* count boosted.
*
* On error, an nfsstat value in network byte order is returned.
*/
__be32
nfsd_file_acquire_local(struct net *net, struct svc_cred *cred,
struct auth_domain *client, struct svc_fh *fhp,
unsigned int may_flags, struct nfsd_file **pnf)
{
/*
* Save creds before calling nfsd_file_do_acquire() (which calls
* nfsd_setuser). Important because caller (LOCALIO) is from
* client context.
*/
const struct cred *save_cred = get_current_cred();
__be32 beres;
beres = nfsd_file_do_acquire(NULL, net, cred, client,
fhp, may_flags, NULL, pnf, true);
revert_creds(save_cred);
return beres;
}
/**
* nfsd_file_acquire_opened - Get a struct nfsd_file using existing open file
* @rqstp: the RPC transaction being executed
* @fhp: the NFS filehandle of the file just created
* @may_flags: NFSD_MAY_ settings for the file
* @file: cached, already-open file (may be NULL)
* @pnf: OUT: new or found "struct nfsd_file" object
*
* Acquire a nfsd_file object that is not GC'ed. If one doesn't already exist,
* and @file is non-NULL, use it to instantiate a new nfsd_file instead of
* opening a new one.
*
* Return values:
* %nfs_ok - @pnf points to an nfsd_file with its reference
* count boosted.
*
* On error, an nfsstat value in network byte order is returned.
*/
__be32
nfsd_file_acquire_opened(struct svc_rqst *rqstp, struct svc_fh *fhp,
unsigned int may_flags, struct file *file,
struct nfsd_file **pnf)
{
return nfsd_file_do_acquire(rqstp, SVC_NET(rqstp), NULL, NULL,
fhp, may_flags, file, pnf, false);
}
/*
* Note that fields may be added, removed or reordered in the future. Programs
* scraping this file for info should test the labels to ensure they're
* getting the correct field.
*/
int nfsd_file_cache_stats_show(struct seq_file *m, void *v)
{
unsigned long allocations = 0, releases = 0, evictions = 0;
unsigned long hits = 0, acquisitions = 0;
unsigned int i, count = 0, buckets = 0;
unsigned long lru = 0, total_age = 0;
/* Serialize with server shutdown */
mutex_lock(&nfsd_mutex);
if (test_bit(NFSD_FILE_CACHE_UP, &nfsd_file_flags) == 1) {
struct bucket_table *tbl;
struct rhashtable *ht;
lru = list_lru_count(&nfsd_file_lru);
rcu_read_lock();
ht = &nfsd_file_rhltable.ht;
count = atomic_read(&ht->nelems);
tbl = rht_dereference_rcu(ht->tbl, ht);
buckets = tbl->size;
rcu_read_unlock();
}
mutex_unlock(&nfsd_mutex);
for_each_possible_cpu(i) {
hits += per_cpu(nfsd_file_cache_hits, i);
acquisitions += per_cpu(nfsd_file_acquisitions, i);
allocations += per_cpu(nfsd_file_allocations, i);
releases += per_cpu(nfsd_file_releases, i);
total_age += per_cpu(nfsd_file_total_age, i);
evictions += per_cpu(nfsd_file_evictions, i);
}
seq_printf(m, "total inodes: %u\n", count);
seq_printf(m, "hash buckets: %u\n", buckets);
seq_printf(m, "lru entries: %lu\n", lru);
seq_printf(m, "cache hits: %lu\n", hits);
seq_printf(m, "acquisitions: %lu\n", acquisitions);
seq_printf(m, "allocations: %lu\n", allocations);
seq_printf(m, "releases: %lu\n", releases);
seq_printf(m, "evictions: %lu\n", evictions);
if (releases)
seq_printf(m, "mean age (ms): %ld\n", total_age / releases);
else
seq_printf(m, "mean age (ms): -\n");
return 0;
}
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