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![Dai Ngo](/assets/img/avatar_default.png)
The following request sequence to the same file causes the NFS client and
server getting into an infinite loop with COMMIT and NFS4ERR_DELAY:
OPEN
REMOVE
WRITE
COMMIT
Problem reported by recall11, recall12, recall14, recall20, recall22,
recall40, recall42, recall48, recall50 of nfstest suite.
This patch restores the handling of race condition in nfsd_file_do_acquire
with unlink to that prior of the regression.
Fixes: ac3a2585f0
("nfsd: rework refcounting in filecache")
Signed-off-by: Dai Ngo <dai.ngo@oracle.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
1238 lines
32 KiB
C
1238 lines
32 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* The NFSD open file cache.
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*
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* (c) 2015 - Jeff Layton <jeff.layton@primarydata.com>
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*
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* An nfsd_file object is a per-file collection of open state that binds
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* together:
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* - a struct file *
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* - a user credential
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* - a network namespace
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* - a read-ahead context
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* - monitoring for writeback errors
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*
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* nfsd_file objects are reference-counted. Consumers acquire a new
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* object via the nfsd_file_acquire API. They manage their interest in
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* the acquired object, and hence the object's reference count, via
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* nfsd_file_get and nfsd_file_put. There are two varieties of nfsd_file
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* object:
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*
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* * non-garbage-collected: When a consumer wants to precisely control
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* the lifetime of a file's open state, it acquires a non-garbage-
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* collected nfsd_file. The final nfsd_file_put releases the open
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* state immediately.
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*
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* * garbage-collected: When a consumer does not control the lifetime
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* of open state, it acquires a garbage-collected nfsd_file. The
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* final nfsd_file_put allows the open state to linger for a period
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* during which it may be re-used.
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*/
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#include <linux/hash.h>
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#include <linux/slab.h>
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#include <linux/file.h>
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#include <linux/pagemap.h>
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#include <linux/sched.h>
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#include <linux/list_lru.h>
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#include <linux/fsnotify_backend.h>
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#include <linux/fsnotify.h>
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#include <linux/seq_file.h>
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#include <linux/rhashtable.h>
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#include "vfs.h"
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#include "nfsd.h"
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#include "nfsfh.h"
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#include "netns.h"
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#include "filecache.h"
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#include "trace.h"
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#define NFSD_LAUNDRETTE_DELAY (2 * HZ)
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#define NFSD_FILE_CACHE_UP (0)
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/* We only care about NFSD_MAY_READ/WRITE for this cache */
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#define NFSD_FILE_MAY_MASK (NFSD_MAY_READ|NFSD_MAY_WRITE)
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static DEFINE_PER_CPU(unsigned long, nfsd_file_cache_hits);
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static DEFINE_PER_CPU(unsigned long, nfsd_file_acquisitions);
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static DEFINE_PER_CPU(unsigned long, nfsd_file_releases);
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static DEFINE_PER_CPU(unsigned long, nfsd_file_total_age);
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static DEFINE_PER_CPU(unsigned long, nfsd_file_evictions);
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struct nfsd_fcache_disposal {
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struct work_struct work;
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spinlock_t lock;
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struct list_head freeme;
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};
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static struct workqueue_struct *nfsd_filecache_wq __read_mostly;
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static struct kmem_cache *nfsd_file_slab;
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static struct kmem_cache *nfsd_file_mark_slab;
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static struct list_lru nfsd_file_lru;
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static unsigned long nfsd_file_flags;
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static struct fsnotify_group *nfsd_file_fsnotify_group;
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static struct delayed_work nfsd_filecache_laundrette;
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static struct rhltable nfsd_file_rhltable
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____cacheline_aligned_in_smp;
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static bool
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nfsd_match_cred(const struct cred *c1, const struct cred *c2)
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{
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int i;
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if (!uid_eq(c1->fsuid, c2->fsuid))
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return false;
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if (!gid_eq(c1->fsgid, c2->fsgid))
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return false;
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if (c1->group_info == NULL || c2->group_info == NULL)
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return c1->group_info == c2->group_info;
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if (c1->group_info->ngroups != c2->group_info->ngroups)
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return false;
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for (i = 0; i < c1->group_info->ngroups; i++) {
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if (!gid_eq(c1->group_info->gid[i], c2->group_info->gid[i]))
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return false;
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}
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return true;
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}
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static const struct rhashtable_params nfsd_file_rhash_params = {
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.key_len = sizeof_field(struct nfsd_file, nf_inode),
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.key_offset = offsetof(struct nfsd_file, nf_inode),
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.head_offset = offsetof(struct nfsd_file, nf_rlist),
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/*
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* Start with a single page hash table to reduce resizing churn
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* on light workloads.
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*/
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.min_size = 256,
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.automatic_shrinking = true,
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};
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static void
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nfsd_file_schedule_laundrette(void)
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{
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if (test_bit(NFSD_FILE_CACHE_UP, &nfsd_file_flags))
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queue_delayed_work(system_wq, &nfsd_filecache_laundrette,
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NFSD_LAUNDRETTE_DELAY);
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}
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static void
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nfsd_file_slab_free(struct rcu_head *rcu)
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{
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struct nfsd_file *nf = container_of(rcu, struct nfsd_file, nf_rcu);
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put_cred(nf->nf_cred);
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kmem_cache_free(nfsd_file_slab, nf);
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}
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static void
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nfsd_file_mark_free(struct fsnotify_mark *mark)
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{
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struct nfsd_file_mark *nfm = container_of(mark, struct nfsd_file_mark,
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nfm_mark);
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kmem_cache_free(nfsd_file_mark_slab, nfm);
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}
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static struct nfsd_file_mark *
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nfsd_file_mark_get(struct nfsd_file_mark *nfm)
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{
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if (!refcount_inc_not_zero(&nfm->nfm_ref))
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return NULL;
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return nfm;
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}
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static void
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nfsd_file_mark_put(struct nfsd_file_mark *nfm)
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{
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if (refcount_dec_and_test(&nfm->nfm_ref)) {
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fsnotify_destroy_mark(&nfm->nfm_mark, nfsd_file_fsnotify_group);
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fsnotify_put_mark(&nfm->nfm_mark);
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}
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}
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static struct nfsd_file_mark *
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nfsd_file_mark_find_or_create(struct nfsd_file *nf, struct inode *inode)
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{
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int err;
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struct fsnotify_mark *mark;
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struct nfsd_file_mark *nfm = NULL, *new;
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do {
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fsnotify_group_lock(nfsd_file_fsnotify_group);
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mark = fsnotify_find_mark(&inode->i_fsnotify_marks,
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nfsd_file_fsnotify_group);
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if (mark) {
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nfm = nfsd_file_mark_get(container_of(mark,
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struct nfsd_file_mark,
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nfm_mark));
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fsnotify_group_unlock(nfsd_file_fsnotify_group);
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if (nfm) {
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fsnotify_put_mark(mark);
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break;
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}
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/* Avoid soft lockup race with nfsd_file_mark_put() */
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fsnotify_destroy_mark(mark, nfsd_file_fsnotify_group);
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fsnotify_put_mark(mark);
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} else {
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fsnotify_group_unlock(nfsd_file_fsnotify_group);
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}
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/* allocate a new nfm */
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new = kmem_cache_alloc(nfsd_file_mark_slab, GFP_KERNEL);
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if (!new)
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return NULL;
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fsnotify_init_mark(&new->nfm_mark, nfsd_file_fsnotify_group);
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new->nfm_mark.mask = FS_ATTRIB|FS_DELETE_SELF;
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refcount_set(&new->nfm_ref, 1);
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err = fsnotify_add_inode_mark(&new->nfm_mark, inode, 0);
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/*
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* If the add was successful, then return the object.
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* Otherwise, we need to put the reference we hold on the
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* nfm_mark. The fsnotify code will take a reference and put
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* it on failure, so we can't just free it directly. It's also
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* not safe to call fsnotify_destroy_mark on it as the
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* mark->group will be NULL. Thus, we can't let the nfm_ref
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* counter drive the destruction at this point.
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*/
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if (likely(!err))
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nfm = new;
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else
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fsnotify_put_mark(&new->nfm_mark);
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} while (unlikely(err == -EEXIST));
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return nfm;
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}
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static struct nfsd_file *
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nfsd_file_alloc(struct net *net, struct inode *inode, unsigned char need,
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bool want_gc)
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{
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struct nfsd_file *nf;
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nf = kmem_cache_alloc(nfsd_file_slab, GFP_KERNEL);
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if (unlikely(!nf))
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return NULL;
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INIT_LIST_HEAD(&nf->nf_lru);
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nf->nf_birthtime = ktime_get();
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nf->nf_file = NULL;
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nf->nf_cred = get_current_cred();
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nf->nf_net = net;
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nf->nf_flags = want_gc ?
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BIT(NFSD_FILE_HASHED) | BIT(NFSD_FILE_PENDING) | BIT(NFSD_FILE_GC) :
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BIT(NFSD_FILE_HASHED) | BIT(NFSD_FILE_PENDING);
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nf->nf_inode = inode;
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refcount_set(&nf->nf_ref, 1);
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nf->nf_may = need;
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nf->nf_mark = NULL;
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return nf;
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}
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/**
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* nfsd_file_check_write_error - check for writeback errors on a file
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* @nf: nfsd_file to check for writeback errors
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*
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* Check whether a nfsd_file has an unseen error. Reset the write
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* verifier if so.
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*/
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static void
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nfsd_file_check_write_error(struct nfsd_file *nf)
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{
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struct file *file = nf->nf_file;
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if ((file->f_mode & FMODE_WRITE) &&
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filemap_check_wb_err(file->f_mapping, READ_ONCE(file->f_wb_err)))
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nfsd_reset_write_verifier(net_generic(nf->nf_net, nfsd_net_id));
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}
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static void
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nfsd_file_hash_remove(struct nfsd_file *nf)
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{
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trace_nfsd_file_unhash(nf);
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rhltable_remove(&nfsd_file_rhltable, &nf->nf_rlist,
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nfsd_file_rhash_params);
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}
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static bool
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nfsd_file_unhash(struct nfsd_file *nf)
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{
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if (test_and_clear_bit(NFSD_FILE_HASHED, &nf->nf_flags)) {
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nfsd_file_hash_remove(nf);
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return true;
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}
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return false;
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}
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static void
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nfsd_file_free(struct nfsd_file *nf)
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{
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s64 age = ktime_to_ms(ktime_sub(ktime_get(), nf->nf_birthtime));
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trace_nfsd_file_free(nf);
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this_cpu_inc(nfsd_file_releases);
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this_cpu_add(nfsd_file_total_age, age);
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nfsd_file_unhash(nf);
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if (nf->nf_mark)
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nfsd_file_mark_put(nf->nf_mark);
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if (nf->nf_file) {
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nfsd_file_check_write_error(nf);
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filp_close(nf->nf_file, NULL);
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}
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/*
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* If this item is still linked via nf_lru, that's a bug.
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* WARN and leak it to preserve system stability.
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*/
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if (WARN_ON_ONCE(!list_empty(&nf->nf_lru)))
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return;
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call_rcu(&nf->nf_rcu, nfsd_file_slab_free);
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}
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static bool
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nfsd_file_check_writeback(struct nfsd_file *nf)
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{
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struct file *file = nf->nf_file;
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struct address_space *mapping;
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/* File not open for write? */
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if (!(file->f_mode & FMODE_WRITE))
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return false;
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/*
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* Some filesystems (e.g. NFS) flush all dirty data on close.
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* On others, there is no need to wait for writeback.
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*/
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if (!(file_inode(file)->i_sb->s_export_op->flags & EXPORT_OP_FLUSH_ON_CLOSE))
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return false;
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mapping = file->f_mapping;
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return mapping_tagged(mapping, PAGECACHE_TAG_DIRTY) ||
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mapping_tagged(mapping, PAGECACHE_TAG_WRITEBACK);
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}
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static bool nfsd_file_lru_add(struct nfsd_file *nf)
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{
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set_bit(NFSD_FILE_REFERENCED, &nf->nf_flags);
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if (list_lru_add(&nfsd_file_lru, &nf->nf_lru)) {
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trace_nfsd_file_lru_add(nf);
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return true;
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}
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return false;
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}
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static bool nfsd_file_lru_remove(struct nfsd_file *nf)
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{
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if (list_lru_del(&nfsd_file_lru, &nf->nf_lru)) {
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trace_nfsd_file_lru_del(nf);
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return true;
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}
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return false;
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}
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struct nfsd_file *
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nfsd_file_get(struct nfsd_file *nf)
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{
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if (nf && refcount_inc_not_zero(&nf->nf_ref))
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return nf;
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return NULL;
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}
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/**
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* nfsd_file_put - put the reference to a nfsd_file
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* @nf: nfsd_file of which to put the reference
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*
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* Put a reference to a nfsd_file. In the non-GC case, we just put the
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* reference immediately. In the GC case, if the reference would be
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* the last one, the put it on the LRU instead to be cleaned up later.
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*/
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void
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nfsd_file_put(struct nfsd_file *nf)
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{
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might_sleep();
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trace_nfsd_file_put(nf);
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if (test_bit(NFSD_FILE_GC, &nf->nf_flags) &&
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test_bit(NFSD_FILE_HASHED, &nf->nf_flags)) {
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/*
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* If this is the last reference (nf_ref == 1), then try to
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* transfer it to the LRU.
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*/
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if (refcount_dec_not_one(&nf->nf_ref))
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return;
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/* Try to add it to the LRU. If that fails, decrement. */
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if (nfsd_file_lru_add(nf)) {
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/* If it's still hashed, we're done */
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if (test_bit(NFSD_FILE_HASHED, &nf->nf_flags)) {
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nfsd_file_schedule_laundrette();
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return;
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}
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/*
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* We're racing with unhashing, so try to remove it from
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* the LRU. If removal fails, then someone else already
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* has our reference.
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*/
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if (!nfsd_file_lru_remove(nf))
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return;
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}
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}
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if (refcount_dec_and_test(&nf->nf_ref))
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nfsd_file_free(nf);
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}
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static void
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nfsd_file_dispose_list(struct list_head *dispose)
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{
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struct nfsd_file *nf;
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while (!list_empty(dispose)) {
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nf = list_first_entry(dispose, struct nfsd_file, nf_lru);
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list_del_init(&nf->nf_lru);
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nfsd_file_free(nf);
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}
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}
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/**
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* nfsd_file_dispose_list_delayed - move list of dead files to net's freeme list
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* @dispose: list of nfsd_files to be disposed
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*
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* Transfers each file to the "freeme" list for its nfsd_net, to eventually
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* be disposed of by the per-net garbage collector.
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*/
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static void
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nfsd_file_dispose_list_delayed(struct list_head *dispose)
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{
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while(!list_empty(dispose)) {
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struct nfsd_file *nf = list_first_entry(dispose,
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struct nfsd_file, nf_lru);
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struct nfsd_net *nn = net_generic(nf->nf_net, nfsd_net_id);
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struct nfsd_fcache_disposal *l = nn->fcache_disposal;
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spin_lock(&l->lock);
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list_move_tail(&nf->nf_lru, &l->freeme);
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spin_unlock(&l->lock);
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queue_work(nfsd_filecache_wq, &l->work);
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}
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}
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/**
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* nfsd_file_lru_cb - Examine an entry on the LRU list
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* @item: LRU entry to examine
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* @lru: controlling LRU
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* @lock: LRU list lock (unused)
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* @arg: dispose list
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*
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* Return values:
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* %LRU_REMOVED: @item was removed from the LRU
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* %LRU_ROTATE: @item is to be moved to the LRU tail
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* %LRU_SKIP: @item cannot be evicted
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*/
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static enum lru_status
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nfsd_file_lru_cb(struct list_head *item, struct list_lru_one *lru,
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spinlock_t *lock, void *arg)
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__releases(lock)
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__acquires(lock)
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{
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struct list_head *head = arg;
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struct nfsd_file *nf = list_entry(item, struct nfsd_file, nf_lru);
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/* We should only be dealing with GC entries here */
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WARN_ON_ONCE(!test_bit(NFSD_FILE_GC, &nf->nf_flags));
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/*
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* Don't throw out files that are still undergoing I/O or
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* that have uncleared errors pending.
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*/
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if (nfsd_file_check_writeback(nf)) {
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trace_nfsd_file_gc_writeback(nf);
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return LRU_SKIP;
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}
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/* If it was recently added to the list, skip it */
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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_move(lru, &nf->nf_lru, 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 = {
|
|
.scan_objects = nfsd_file_lru_scan,
|
|
.count_objects = nfsd_file_lru_count,
|
|
.seeks = 1,
|
|
};
|
|
|
|
/**
|
|
* 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_lru, 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_lru);
|
|
list_del_init(&nf->nf_lru);
|
|
nfsd_file_free(nf);
|
|
}
|
|
flush_delayed_fput();
|
|
}
|
|
|
|
/**
|
|
* nfsd_file_delayed_close - close unused nfsd_files
|
|
* @work: dummy
|
|
*
|
|
* Scrape the freeme list for this nfsd_net, and then dispose of them
|
|
* all.
|
|
*/
|
|
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);
|
|
|
|
spin_lock(&l->lock);
|
|
list_splice_init(&l->freeme, &head);
|
|
spin_unlock(&l->lock);
|
|
|
|
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(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)
|
|
{
|
|
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_filecache_wq = alloc_workqueue("nfsd_filecache", 0, 0);
|
|
if (!nfsd_filecache_wq)
|
|
goto out;
|
|
|
|
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, "nfsd-filecache");
|
|
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,
|
|
FSNOTIFY_GROUP_NOFS);
|
|
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:
|
|
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;
|
|
destroy_workqueue(nfsd_filecache_wq);
|
|
nfsd_filecache_wq = 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;
|
|
INIT_WORK(&l->work, nfsd_file_delayed_close);
|
|
spin_lock_init(&l->lock);
|
|
INIT_LIST_HEAD(&l->freeme);
|
|
return l;
|
|
}
|
|
|
|
static void
|
|
nfsd_free_fcache_disposal(struct nfsd_fcache_disposal *l)
|
|
{
|
|
cancel_work_sync(&l->work);
|
|
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);
|
|
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;
|
|
destroy_workqueue(nfsd_filecache_wq);
|
|
nfsd_filecache_wq = 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_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 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 net *net = SVC_NET(rqstp);
|
|
struct nfsd_file *new, *nf;
|
|
const struct cred *cred;
|
|
bool open_retry = true;
|
|
struct inode *inode;
|
|
__be32 status;
|
|
int ret;
|
|
|
|
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);
|
|
cred = get_current_cred();
|
|
|
|
retry:
|
|
rcu_read_lock();
|
|
nf = nfsd_file_lookup_locked(net, 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, cred, inode, need, want_gc);
|
|
if (unlikely(nf)) {
|
|
spin_unlock(&inode->i_lock);
|
|
rcu_read_unlock();
|
|
nfsd_file_slab_free(&new->nf_rcu);
|
|
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;
|
|
|
|
if (ret == -EEXIST)
|
|
goto retry;
|
|
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;
|
|
}
|
|
open_retry = false;
|
|
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;
|
|
}
|
|
put_cred(cred);
|
|
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(nf, inode);
|
|
if (nf->nf_mark) {
|
|
if (file) {
|
|
get_file(file);
|
|
nf->nf_file = file;
|
|
status = nfs_ok;
|
|
trace_nfsd_file_opened(nf, status);
|
|
} else {
|
|
status = nfsd_open_verified(rqstp, fhp, may_flags,
|
|
&nf->nf_file);
|
|
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, 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, fhp, may_flags, NULL, pnf, false);
|
|
}
|
|
|
|
/**
|
|
* 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, 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 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);
|
|
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, "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;
|
|
}
|