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- /*
- * Open file cache.
- *
- * (c) 2015 - Jeff Layton <jeff.layton@primarydata.com>
- */
- #include <linux/hash.h>
- #include <linux/slab.h>
- #include <linux/file.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 "vfs.h"
- #include "nfsd.h"
- #include "nfsfh.h"
- #include "netns.h"
- #include "filecache.h"
- #include "trace.h"
- #define NFSDDBG_FACILITY NFSDDBG_FH
- /* FIXME: dynamically size this for the machine somehow? */
- #define NFSD_FILE_HASH_BITS 12
- #define NFSD_FILE_HASH_SIZE (1 << NFSD_FILE_HASH_BITS)
- #define NFSD_LAUNDRETTE_DELAY (2 * HZ)
- #define NFSD_FILE_SHUTDOWN (1)
- #define NFSD_FILE_LRU_THRESHOLD (4096UL)
- #define NFSD_FILE_LRU_LIMIT (NFSD_FILE_LRU_THRESHOLD << 2)
- /* We only care about NFSD_MAY_READ/WRITE for this cache */
- #define NFSD_FILE_MAY_MASK (NFSD_MAY_READ|NFSD_MAY_WRITE)
- struct nfsd_fcache_bucket {
- struct hlist_head nfb_head;
- spinlock_t nfb_lock;
- unsigned int nfb_count;
- unsigned int nfb_maxcount;
- };
- static DEFINE_PER_CPU(unsigned long, nfsd_file_cache_hits);
- struct nfsd_fcache_disposal {
- struct list_head list;
- struct work_struct work;
- struct net *net;
- spinlock_t lock;
- struct list_head freeme;
- struct rcu_head rcu;
- };
- static struct workqueue_struct *nfsd_filecache_wq __read_mostly;
- static struct kmem_cache *nfsd_file_slab;
- static struct kmem_cache *nfsd_file_mark_slab;
- static struct nfsd_fcache_bucket *nfsd_file_hashtbl;
- static struct list_lru nfsd_file_lru;
- static long nfsd_file_lru_flags;
- static struct fsnotify_group *nfsd_file_fsnotify_group;
- static atomic_long_t nfsd_filecache_count;
- static struct delayed_work nfsd_filecache_laundrette;
- static DEFINE_SPINLOCK(laundrette_lock);
- static LIST_HEAD(laundrettes);
- static void nfsd_file_gc(void);
- static void
- nfsd_file_schedule_laundrette(void)
- {
- long count = atomic_long_read(&nfsd_filecache_count);
- if (count == 0 || test_bit(NFSD_FILE_SHUTDOWN, &nfsd_file_lru_flags))
- return;
- queue_delayed_work(system_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 nfsd_file *nf)
- {
- int err;
- struct fsnotify_mark *mark;
- struct nfsd_file_mark *nfm = NULL, *new;
- struct inode *inode = nf->nf_inode;
- do {
- mutex_lock(&nfsd_file_fsnotify_group->mark_mutex);
- mark = fsnotify_find_mark(&inode->i_fsnotify_marks,
- nfsd_file_fsnotify_group);
- if (mark) {
- nfm = nfsd_file_mark_get(container_of(mark,
- struct nfsd_file_mark,
- nfm_mark));
- mutex_unlock(&nfsd_file_fsnotify_group->mark_mutex);
- 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
- mutex_unlock(&nfsd_file_fsnotify_group->mark_mutex);
- /* 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 inode *inode, unsigned int may, unsigned int hashval,
- struct net *net)
- {
- struct nfsd_file *nf;
- nf = kmem_cache_alloc(nfsd_file_slab, GFP_KERNEL);
- if (nf) {
- INIT_HLIST_NODE(&nf->nf_node);
- INIT_LIST_HEAD(&nf->nf_lru);
- nf->nf_file = NULL;
- nf->nf_cred = get_current_cred();
- nf->nf_net = net;
- nf->nf_flags = 0;
- nf->nf_inode = inode;
- nf->nf_hashval = hashval;
- refcount_set(&nf->nf_ref, 1);
- nf->nf_may = may & NFSD_FILE_MAY_MASK;
- if (may & NFSD_MAY_NOT_BREAK_LEASE) {
- if (may & NFSD_MAY_WRITE)
- __set_bit(NFSD_FILE_BREAK_WRITE, &nf->nf_flags);
- if (may & NFSD_MAY_READ)
- __set_bit(NFSD_FILE_BREAK_READ, &nf->nf_flags);
- }
- nf->nf_mark = NULL;
- init_rwsem(&nf->nf_rwsem);
- trace_nfsd_file_alloc(nf);
- }
- return nf;
- }
- static bool
- nfsd_file_free(struct nfsd_file *nf)
- {
- bool flush = false;
- trace_nfsd_file_put_final(nf);
- if (nf->nf_mark)
- nfsd_file_mark_put(nf->nf_mark);
- if (nf->nf_file) {
- get_file(nf->nf_file);
- filp_close(nf->nf_file, NULL);
- fput(nf->nf_file);
- flush = true;
- }
- call_rcu(&nf->nf_rcu, nfsd_file_slab_free);
- return flush;
- }
- static bool
- nfsd_file_check_writeback(struct nfsd_file *nf)
- {
- struct file *file = nf->nf_file;
- struct address_space *mapping;
- if (!file || !(file->f_mode & FMODE_WRITE))
- return false;
- mapping = file->f_mapping;
- return mapping_tagged(mapping, PAGECACHE_TAG_DIRTY) ||
- mapping_tagged(mapping, PAGECACHE_TAG_WRITEBACK);
- }
- static int
- nfsd_file_check_write_error(struct nfsd_file *nf)
- {
- struct file *file = nf->nf_file;
- if (!file || !(file->f_mode & FMODE_WRITE))
- return 0;
- return filemap_check_wb_err(file->f_mapping, READ_ONCE(file->f_wb_err));
- }
- static void
- nfsd_file_do_unhash(struct nfsd_file *nf)
- {
- lockdep_assert_held(&nfsd_file_hashtbl[nf->nf_hashval].nfb_lock);
- trace_nfsd_file_unhash(nf);
- if (nfsd_file_check_write_error(nf))
- nfsd_reset_boot_verifier(net_generic(nf->nf_net, nfsd_net_id));
- --nfsd_file_hashtbl[nf->nf_hashval].nfb_count;
- hlist_del_rcu(&nf->nf_node);
- atomic_long_dec(&nfsd_filecache_count);
- }
- static bool
- nfsd_file_unhash(struct nfsd_file *nf)
- {
- if (test_and_clear_bit(NFSD_FILE_HASHED, &nf->nf_flags)) {
- nfsd_file_do_unhash(nf);
- if (!list_empty(&nf->nf_lru))
- list_lru_del(&nfsd_file_lru, &nf->nf_lru);
- return true;
- }
- return false;
- }
- /*
- * Return true if the file was unhashed.
- */
- static bool
- nfsd_file_unhash_and_release_locked(struct nfsd_file *nf, struct list_head *dispose)
- {
- lockdep_assert_held(&nfsd_file_hashtbl[nf->nf_hashval].nfb_lock);
- trace_nfsd_file_unhash_and_release_locked(nf);
- if (!nfsd_file_unhash(nf))
- return false;
- /* keep final reference for nfsd_file_lru_dispose */
- if (refcount_dec_not_one(&nf->nf_ref))
- return true;
- list_add(&nf->nf_lru, dispose);
- return true;
- }
- static void
- nfsd_file_put_noref(struct nfsd_file *nf)
- {
- trace_nfsd_file_put(nf);
- if (refcount_dec_and_test(&nf->nf_ref)) {
- WARN_ON(test_bit(NFSD_FILE_HASHED, &nf->nf_flags));
- nfsd_file_free(nf);
- }
- }
- void
- nfsd_file_put(struct nfsd_file *nf)
- {
- bool is_hashed;
- set_bit(NFSD_FILE_REFERENCED, &nf->nf_flags);
- if (refcount_read(&nf->nf_ref) > 2 || !nf->nf_file) {
- nfsd_file_put_noref(nf);
- return;
- }
- filemap_flush(nf->nf_file->f_mapping);
- is_hashed = test_bit(NFSD_FILE_HASHED, &nf->nf_flags) != 0;
- nfsd_file_put_noref(nf);
- if (is_hashed)
- nfsd_file_schedule_laundrette();
- if (atomic_long_read(&nfsd_filecache_count) >= NFSD_FILE_LRU_LIMIT)
- nfsd_file_gc();
- }
- struct nfsd_file *
- nfsd_file_get(struct nfsd_file *nf)
- {
- if (likely(refcount_inc_not_zero(&nf->nf_ref)))
- return nf;
- return NULL;
- }
- 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_lru);
- list_del(&nf->nf_lru);
- nfsd_file_put_noref(nf);
- }
- }
- static void
- nfsd_file_dispose_list_sync(struct list_head *dispose)
- {
- bool flush = false;
- struct nfsd_file *nf;
- while(!list_empty(dispose)) {
- nf = list_first_entry(dispose, struct nfsd_file, nf_lru);
- list_del(&nf->nf_lru);
- if (!refcount_dec_and_test(&nf->nf_ref))
- continue;
- if (nfsd_file_free(nf))
- flush = true;
- }
- if (flush)
- flush_delayed_fput();
- }
- static void
- nfsd_file_list_remove_disposal(struct list_head *dst,
- struct nfsd_fcache_disposal *l)
- {
- spin_lock(&l->lock);
- list_splice_init(&l->freeme, dst);
- spin_unlock(&l->lock);
- }
- static void
- nfsd_file_list_add_disposal(struct list_head *files, struct net *net)
- {
- struct nfsd_fcache_disposal *l;
- rcu_read_lock();
- list_for_each_entry_rcu(l, &laundrettes, list) {
- if (l->net == net) {
- spin_lock(&l->lock);
- list_splice_tail_init(files, &l->freeme);
- spin_unlock(&l->lock);
- queue_work(nfsd_filecache_wq, &l->work);
- break;
- }
- }
- rcu_read_unlock();
- }
- static void
- nfsd_file_list_add_pernet(struct list_head *dst, struct list_head *src,
- struct net *net)
- {
- struct nfsd_file *nf, *tmp;
- list_for_each_entry_safe(nf, tmp, src, nf_lru) {
- if (nf->nf_net == net)
- list_move_tail(&nf->nf_lru, dst);
- }
- }
- static void
- nfsd_file_dispose_list_delayed(struct list_head *dispose)
- {
- LIST_HEAD(list);
- struct nfsd_file *nf;
- while(!list_empty(dispose)) {
- nf = list_first_entry(dispose, struct nfsd_file, nf_lru);
- nfsd_file_list_add_pernet(&list, dispose, nf->nf_net);
- nfsd_file_list_add_disposal(&list, nf->nf_net);
- }
- }
- /*
- * Note this can deadlock with nfsd_file_cache_purge.
- */
- 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);
- /*
- * Do a lockless refcount check. The hashtable holds one reference, so
- * we look to see if anything else has a reference, or if any have
- * been put since the shrinker last ran. Those don't get unhashed and
- * released.
- *
- * Note that in the put path, we set the flag and then decrement the
- * counter. Here we check the counter and then test and clear the flag.
- * That order is deliberate to ensure that we can do this locklessly.
- */
- if (refcount_read(&nf->nf_ref) > 1)
- goto out_skip;
- /*
- * Don't throw out files that are still undergoing I/O or
- * that have uncleared errors pending.
- */
- if (nfsd_file_check_writeback(nf))
- goto out_skip;
- if (test_and_clear_bit(NFSD_FILE_REFERENCED, &nf->nf_flags))
- goto out_skip;
- if (!test_and_clear_bit(NFSD_FILE_HASHED, &nf->nf_flags))
- goto out_skip;
- list_lru_isolate_move(lru, &nf->nf_lru, head);
- return LRU_REMOVED;
- out_skip:
- return LRU_SKIP;
- }
- static unsigned long
- nfsd_file_lru_walk_list(struct shrink_control *sc)
- {
- LIST_HEAD(head);
- struct nfsd_file *nf;
- unsigned long ret;
- if (sc)
- ret = list_lru_shrink_walk(&nfsd_file_lru, sc,
- nfsd_file_lru_cb, &head);
- else
- ret = list_lru_walk(&nfsd_file_lru,
- nfsd_file_lru_cb,
- &head, LONG_MAX);
- list_for_each_entry(nf, &head, nf_lru) {
- spin_lock(&nfsd_file_hashtbl[nf->nf_hashval].nfb_lock);
- nfsd_file_do_unhash(nf);
- spin_unlock(&nfsd_file_hashtbl[nf->nf_hashval].nfb_lock);
- }
- nfsd_file_dispose_list_delayed(&head);
- return ret;
- }
- static void
- nfsd_file_gc(void)
- {
- nfsd_file_lru_walk_list(NULL);
- }
- static void
- nfsd_file_gc_worker(struct work_struct *work)
- {
- nfsd_file_gc();
- 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)
- {
- return nfsd_file_lru_walk_list(sc);
- }
- static struct shrinker nfsd_file_shrinker = {
- .scan_objects = nfsd_file_lru_scan,
- .count_objects = nfsd_file_lru_count,
- .seeks = 1,
- };
- static void
- __nfsd_file_close_inode(struct inode *inode, unsigned int hashval,
- struct list_head *dispose)
- {
- struct nfsd_file *nf;
- struct hlist_node *tmp;
- spin_lock(&nfsd_file_hashtbl[hashval].nfb_lock);
- hlist_for_each_entry_safe(nf, tmp, &nfsd_file_hashtbl[hashval].nfb_head, nf_node) {
- if (inode == nf->nf_inode)
- nfsd_file_unhash_and_release_locked(nf, dispose);
- }
- spin_unlock(&nfsd_file_hashtbl[hashval].nfb_lock);
- }
- /**
- * nfsd_file_close_inode_sync - attempt to forcibly close a nfsd_file
- * @inode: inode of the file to attempt to remove
- *
- * Walk the whole hash bucket, looking for any files that correspond to "inode".
- * If any do, then unhash them and put the hashtable reference to them and
- * destroy any that had their last reference put. Also ensure that any of the
- * fputs also have their final __fput done as well.
- */
- void
- nfsd_file_close_inode_sync(struct inode *inode)
- {
- unsigned int hashval = (unsigned int)hash_long(inode->i_ino,
- NFSD_FILE_HASH_BITS);
- LIST_HEAD(dispose);
- __nfsd_file_close_inode(inode, hashval, &dispose);
- trace_nfsd_file_close_inode_sync(inode, hashval, !list_empty(&dispose));
- nfsd_file_dispose_list_sync(&dispose);
- }
- /**
- * nfsd_file_close_inode_sync - attempt to forcibly close a nfsd_file
- * @inode: inode of the file to attempt to remove
- *
- * Walk the whole hash bucket, looking for any files that correspond to "inode".
- * If any do, then unhash them and put the hashtable reference to them and
- * destroy any that had their last reference put.
- */
- static void
- nfsd_file_close_inode(struct inode *inode)
- {
- unsigned int hashval = (unsigned int)hash_long(inode->i_ino,
- NFSD_FILE_HASH_BITS);
- LIST_HEAD(dispose);
- __nfsd_file_close_inode(inode, hashval, &dispose);
- trace_nfsd_file_close_inode(inode, hashval, !list_empty(&dispose));
- nfsd_file_dispose_list_delayed(&dispose);
- }
- /**
- * nfsd_file_delayed_close - close unused nfsd_files
- * @work: dummy
- *
- * Walk the LRU list and close any entries that have not been used since
- * the last scan.
- *
- * Note this can deadlock with nfsd_file_cache_purge.
- */
- static void
- nfsd_file_delayed_close(struct work_struct *work)
- {
- LIST_HEAD(head);
- struct nfsd_fcache_disposal *l = container_of(work,
- struct nfsd_fcache_disposal, work);
- nfsd_file_list_remove_disposal(&head, l);
- nfsd_file_dispose_list(&head);
- }
- static int
- nfsd_file_lease_notifier_call(struct notifier_block *nb, unsigned long arg,
- void *data)
- {
- struct file_lock *fl = data;
- /* Only close files for F_SETLEASE leases */
- if (fl->fl_flags & FL_LEASE)
- nfsd_file_close_inode_sync(file_inode(fl->fl_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)
- {
- 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 = -ENOMEM;
- unsigned int i;
- clear_bit(NFSD_FILE_SHUTDOWN, &nfsd_file_lru_flags);
- if (nfsd_file_hashtbl)
- return 0;
- nfsd_filecache_wq = alloc_workqueue("nfsd_filecache", 0, 0);
- if (!nfsd_filecache_wq)
- goto out;
- nfsd_file_hashtbl = kvcalloc(NFSD_FILE_HASH_SIZE,
- sizeof(*nfsd_file_hashtbl), GFP_KERNEL);
- if (!nfsd_file_hashtbl) {
- pr_err("nfsd: unable to allocate nfsd_file_hashtbl\n");
- goto out_err;
- }
- nfsd_file_slab = kmem_cache_create("nfsd_file",
- sizeof(struct nfsd_file), 0, 0, NULL);
- if (!nfsd_file_slab) {
- pr_err("nfsd: unable to create nfsd_file_slab\n");
- goto out_err;
- }
- nfsd_file_mark_slab = kmem_cache_create("nfsd_file_mark",
- sizeof(struct nfsd_file_mark), 0, 0, NULL);
- 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;
- }
- ret = register_shrinker(&nfsd_file_shrinker);
- if (ret) {
- pr_err("nfsd: failed to register nfsd_file_shrinker: %d\n", ret);
- goto out_lru;
- }
- 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);
- if (IS_ERR(nfsd_file_fsnotify_group)) {
- pr_err("nfsd: unable to create fsnotify group: %ld\n",
- PTR_ERR(nfsd_file_fsnotify_group));
- nfsd_file_fsnotify_group = NULL;
- goto out_notifier;
- }
- for (i = 0; i < NFSD_FILE_HASH_SIZE; i++) {
- INIT_HLIST_HEAD(&nfsd_file_hashtbl[i].nfb_head);
- spin_lock_init(&nfsd_file_hashtbl[i].nfb_lock);
- }
- INIT_DELAYED_WORK(&nfsd_filecache_laundrette, nfsd_file_gc_worker);
- out:
- return ret;
- out_notifier:
- lease_unregister_notifier(&nfsd_file_lease_notifier);
- out_shrinker:
- unregister_shrinker(&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;
- kvfree(nfsd_file_hashtbl);
- nfsd_file_hashtbl = NULL;
- destroy_workqueue(nfsd_filecache_wq);
- nfsd_filecache_wq = NULL;
- goto out;
- }
- /*
- * Note this can deadlock with nfsd_file_lru_cb.
- */
- void
- nfsd_file_cache_purge(struct net *net)
- {
- unsigned int i;
- struct nfsd_file *nf;
- struct hlist_node *next;
- LIST_HEAD(dispose);
- bool del;
- if (!nfsd_file_hashtbl)
- return;
- for (i = 0; i < NFSD_FILE_HASH_SIZE; i++) {
- struct nfsd_fcache_bucket *nfb = &nfsd_file_hashtbl[i];
- spin_lock(&nfb->nfb_lock);
- hlist_for_each_entry_safe(nf, next, &nfb->nfb_head, nf_node) {
- if (net && nf->nf_net != net)
- continue;
- del = nfsd_file_unhash_and_release_locked(nf, &dispose);
- /*
- * Deadlock detected! Something marked this entry as
- * unhased, but hasn't removed it from the hash list.
- */
- WARN_ON_ONCE(!del);
- }
- spin_unlock(&nfb->nfb_lock);
- nfsd_file_dispose_list(&dispose);
- }
- }
- static struct nfsd_fcache_disposal *
- nfsd_alloc_fcache_disposal(struct net *net)
- {
- struct nfsd_fcache_disposal *l;
- l = kmalloc(sizeof(*l), GFP_KERNEL);
- if (!l)
- return NULL;
- INIT_WORK(&l->work, nfsd_file_delayed_close);
- l->net = net;
- spin_lock_init(&l->lock);
- INIT_LIST_HEAD(&l->freeme);
- return l;
- }
- static void
- nfsd_free_fcache_disposal(struct nfsd_fcache_disposal *l)
- {
- rcu_assign_pointer(l->net, NULL);
- cancel_work_sync(&l->work);
- nfsd_file_dispose_list(&l->freeme);
- kfree_rcu(l, rcu);
- }
- static void
- nfsd_add_fcache_disposal(struct nfsd_fcache_disposal *l)
- {
- spin_lock(&laundrette_lock);
- list_add_tail_rcu(&l->list, &laundrettes);
- spin_unlock(&laundrette_lock);
- }
- static void
- nfsd_del_fcache_disposal(struct nfsd_fcache_disposal *l)
- {
- spin_lock(&laundrette_lock);
- list_del_rcu(&l->list);
- spin_unlock(&laundrette_lock);
- }
- static int
- nfsd_alloc_fcache_disposal_net(struct net *net)
- {
- struct nfsd_fcache_disposal *l;
- l = nfsd_alloc_fcache_disposal(net);
- if (!l)
- return -ENOMEM;
- nfsd_add_fcache_disposal(l);
- return 0;
- }
- static void
- nfsd_free_fcache_disposal_net(struct net *net)
- {
- struct nfsd_fcache_disposal *l;
- rcu_read_lock();
- list_for_each_entry_rcu(l, &laundrettes, list) {
- if (l->net != net)
- continue;
- nfsd_del_fcache_disposal(l);
- rcu_read_unlock();
- nfsd_free_fcache_disposal(l);
- return;
- }
- rcu_read_unlock();
- }
- int
- nfsd_file_cache_start_net(struct net *net)
- {
- return nfsd_alloc_fcache_disposal_net(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)
- {
- set_bit(NFSD_FILE_SHUTDOWN, &nfsd_file_lru_flags);
- lease_unregister_notifier(&nfsd_file_lease_notifier);
- unregister_shrinker(&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;
- kvfree(nfsd_file_hashtbl);
- nfsd_file_hashtbl = NULL;
- destroy_workqueue(nfsd_filecache_wq);
- nfsd_filecache_wq = NULL;
- }
- 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 struct nfsd_file *
- nfsd_file_find_locked(struct inode *inode, unsigned int may_flags,
- unsigned int hashval, struct net *net)
- {
- struct nfsd_file *nf;
- unsigned char need = may_flags & NFSD_FILE_MAY_MASK;
- hlist_for_each_entry_rcu(nf, &nfsd_file_hashtbl[hashval].nfb_head,
- nf_node, lockdep_is_held(&nfsd_file_hashtbl[hashval].nfb_lock)) {
- if (nf->nf_may != need)
- continue;
- if (nf->nf_inode != inode)
- continue;
- if (nf->nf_net != net)
- continue;
- if (!nfsd_match_cred(nf->nf_cred, current_cred()))
- continue;
- if (!test_bit(NFSD_FILE_HASHED, &nf->nf_flags))
- continue;
- if (nfsd_file_get(nf) != NULL)
- return nf;
- }
- return NULL;
- }
- /**
- * nfsd_file_is_cached - are there any cached open files for this fh?
- * @inode: inode of the file to check
- *
- * Scan the hashtable for open files that match this fh. Returns true if there
- * are any, and false if not.
- */
- bool
- nfsd_file_is_cached(struct inode *inode)
- {
- bool ret = false;
- struct nfsd_file *nf;
- unsigned int hashval;
- hashval = (unsigned int)hash_long(inode->i_ino, NFSD_FILE_HASH_BITS);
- rcu_read_lock();
- hlist_for_each_entry_rcu(nf, &nfsd_file_hashtbl[hashval].nfb_head,
- nf_node) {
- if (inode == nf->nf_inode) {
- ret = true;
- break;
- }
- }
- rcu_read_unlock();
- trace_nfsd_file_is_cached(inode, hashval, (int)ret);
- return ret;
- }
- __be32
- nfsd_file_acquire(struct svc_rqst *rqstp, struct svc_fh *fhp,
- unsigned int may_flags, struct nfsd_file **pnf)
- {
- __be32 status;
- struct net *net = SVC_NET(rqstp);
- struct nfsd_file *nf, *new;
- struct inode *inode;
- unsigned int hashval;
- bool retry = true;
- /* FIXME: skip this if fh_dentry is already set? */
- status = fh_verify(rqstp, fhp, S_IFREG,
- may_flags|NFSD_MAY_OWNER_OVERRIDE);
- if (status != nfs_ok)
- return status;
- inode = d_inode(fhp->fh_dentry);
- hashval = (unsigned int)hash_long(inode->i_ino, NFSD_FILE_HASH_BITS);
- retry:
- rcu_read_lock();
- nf = nfsd_file_find_locked(inode, may_flags, hashval, net);
- rcu_read_unlock();
- if (nf)
- goto wait_for_construction;
- new = nfsd_file_alloc(inode, may_flags, hashval, net);
- if (!new) {
- trace_nfsd_file_acquire(rqstp, hashval, inode, may_flags,
- NULL, nfserr_jukebox);
- return nfserr_jukebox;
- }
- spin_lock(&nfsd_file_hashtbl[hashval].nfb_lock);
- nf = nfsd_file_find_locked(inode, may_flags, hashval, net);
- if (nf == NULL)
- goto open_file;
- spin_unlock(&nfsd_file_hashtbl[hashval].nfb_lock);
- nfsd_file_slab_free(&new->nf_rcu);
- 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)) {
- if (!retry) {
- status = nfserr_jukebox;
- goto out;
- }
- retry = false;
- nfsd_file_put_noref(nf);
- goto retry;
- }
- this_cpu_inc(nfsd_file_cache_hits);
- if (!(may_flags & NFSD_MAY_NOT_BREAK_LEASE)) {
- bool write = (may_flags & NFSD_MAY_WRITE);
- if (test_bit(NFSD_FILE_BREAK_READ, &nf->nf_flags) ||
- (test_bit(NFSD_FILE_BREAK_WRITE, &nf->nf_flags) && write)) {
- status = nfserrno(nfsd_open_break_lease(
- file_inode(nf->nf_file), may_flags));
- if (status == nfs_ok) {
- clear_bit(NFSD_FILE_BREAK_READ, &nf->nf_flags);
- if (write)
- clear_bit(NFSD_FILE_BREAK_WRITE,
- &nf->nf_flags);
- }
- }
- }
- out:
- if (status == nfs_ok) {
- *pnf = nf;
- } else {
- nfsd_file_put(nf);
- nf = NULL;
- }
- trace_nfsd_file_acquire(rqstp, hashval, inode, may_flags, nf, status);
- return status;
- open_file:
- nf = new;
- /* Take reference for the hashtable */
- refcount_inc(&nf->nf_ref);
- __set_bit(NFSD_FILE_HASHED, &nf->nf_flags);
- __set_bit(NFSD_FILE_PENDING, &nf->nf_flags);
- list_lru_add(&nfsd_file_lru, &nf->nf_lru);
- hlist_add_head_rcu(&nf->nf_node, &nfsd_file_hashtbl[hashval].nfb_head);
- ++nfsd_file_hashtbl[hashval].nfb_count;
- nfsd_file_hashtbl[hashval].nfb_maxcount = max(nfsd_file_hashtbl[hashval].nfb_maxcount,
- nfsd_file_hashtbl[hashval].nfb_count);
- spin_unlock(&nfsd_file_hashtbl[hashval].nfb_lock);
- if (atomic_long_inc_return(&nfsd_filecache_count) >= NFSD_FILE_LRU_THRESHOLD)
- nfsd_file_gc();
- nf->nf_mark = nfsd_file_mark_find_or_create(nf);
- if (nf->nf_mark)
- status = nfsd_open_verified(rqstp, fhp, S_IFREG,
- may_flags, &nf->nf_file);
- 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) {
- bool do_free;
- spin_lock(&nfsd_file_hashtbl[hashval].nfb_lock);
- do_free = nfsd_file_unhash(nf);
- spin_unlock(&nfsd_file_hashtbl[hashval].nfb_lock);
- if (do_free)
- nfsd_file_put_noref(nf);
- }
- clear_bit_unlock(NFSD_FILE_PENDING, &nf->nf_flags);
- smp_mb__after_atomic();
- wake_up_bit(&nf->nf_flags, NFSD_FILE_PENDING);
- goto out;
- }
- /*
- * 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.
- */
- static int nfsd_file_cache_stats_show(struct seq_file *m, void *v)
- {
- unsigned int i, count = 0, longest = 0;
- unsigned long hits = 0;
- /*
- * No need for spinlocks here since we're not terribly interested in
- * accuracy. We do take the nfsd_mutex simply to ensure that we
- * don't end up racing with server shutdown
- */
- mutex_lock(&nfsd_mutex);
- if (nfsd_file_hashtbl) {
- for (i = 0; i < NFSD_FILE_HASH_SIZE; i++) {
- count += nfsd_file_hashtbl[i].nfb_count;
- longest = max(longest, nfsd_file_hashtbl[i].nfb_count);
- }
- }
- mutex_unlock(&nfsd_mutex);
- for_each_possible_cpu(i)
- hits += per_cpu(nfsd_file_cache_hits, i);
- seq_printf(m, "total entries: %u\n", count);
- seq_printf(m, "longest chain: %u\n", longest);
- seq_printf(m, "cache hits: %lu\n", hits);
- return 0;
- }
- int nfsd_file_cache_stats_open(struct inode *inode, struct file *file)
- {
- return single_open(file, nfsd_file_cache_stats_show, NULL);
- }
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