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![Shyam Prasad N](/assets/img/avatar_default.png)
We had a couple of checks for session in cifs_tree_connect and cifs_mark_open_files_invalid, which were unnecessary. And that was done with ses_lock. Changed that to tc_lock too. Signed-off-by: Shyam Prasad N <sprasad@microsoft.com> Reviewed-by: Paulo Alcantara (SUSE) <pc@manguebit.com> Signed-off-by: Steve French <stfrench@microsoft.com>
1318 lines
31 KiB
C
1318 lines
31 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* DFS referral cache routines
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*
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* Copyright (c) 2018-2019 Paulo Alcantara <palcantara@suse.de>
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*/
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#include <linux/jhash.h>
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#include <linux/ktime.h>
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#include <linux/slab.h>
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#include <linux/proc_fs.h>
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#include <linux/nls.h>
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#include <linux/workqueue.h>
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#include <linux/uuid.h>
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#include "cifsglob.h"
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#include "smb2pdu.h"
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#include "smb2proto.h"
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#include "cifsproto.h"
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#include "cifs_debug.h"
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#include "cifs_unicode.h"
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#include "smb2glob.h"
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#include "dns_resolve.h"
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#include "dfs_cache.h"
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#define CACHE_HTABLE_SIZE 32
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#define CACHE_MAX_ENTRIES 64
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#define CACHE_MIN_TTL 120 /* 2 minutes */
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#define IS_DFS_INTERLINK(v) (((v) & DFSREF_REFERRAL_SERVER) && !((v) & DFSREF_STORAGE_SERVER))
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struct cache_dfs_tgt {
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char *name;
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int path_consumed;
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struct list_head list;
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};
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struct cache_entry {
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struct hlist_node hlist;
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const char *path;
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int hdr_flags; /* RESP_GET_DFS_REFERRAL.ReferralHeaderFlags */
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int ttl; /* DFS_REREFERRAL_V3.TimeToLive */
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int srvtype; /* DFS_REREFERRAL_V3.ServerType */
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int ref_flags; /* DFS_REREFERRAL_V3.ReferralEntryFlags */
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struct timespec64 etime;
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int path_consumed; /* RESP_GET_DFS_REFERRAL.PathConsumed */
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int numtgts;
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struct list_head tlist;
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struct cache_dfs_tgt *tgthint;
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};
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static struct kmem_cache *cache_slab __read_mostly;
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static struct workqueue_struct *dfscache_wq __read_mostly;
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static int cache_ttl;
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static DEFINE_SPINLOCK(cache_ttl_lock);
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static struct nls_table *cache_cp;
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/*
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* Number of entries in the cache
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*/
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static atomic_t cache_count;
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static struct hlist_head cache_htable[CACHE_HTABLE_SIZE];
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static DECLARE_RWSEM(htable_rw_lock);
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static void refresh_cache_worker(struct work_struct *work);
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static DECLARE_DELAYED_WORK(refresh_task, refresh_cache_worker);
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/**
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* dfs_cache_canonical_path - get a canonical DFS path
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*
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* @path: DFS path
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* @cp: codepage
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* @remap: mapping type
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*
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* Return canonical path if success, otherwise error.
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*/
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char *dfs_cache_canonical_path(const char *path, const struct nls_table *cp, int remap)
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{
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char *tmp;
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int plen = 0;
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char *npath;
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if (!path || strlen(path) < 3 || (*path != '\\' && *path != '/'))
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return ERR_PTR(-EINVAL);
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if (unlikely(strcmp(cp->charset, cache_cp->charset))) {
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tmp = (char *)cifs_strndup_to_utf16(path, strlen(path), &plen, cp, remap);
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if (!tmp) {
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cifs_dbg(VFS, "%s: failed to convert path to utf16\n", __func__);
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return ERR_PTR(-EINVAL);
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}
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npath = cifs_strndup_from_utf16(tmp, plen, true, cache_cp);
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kfree(tmp);
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if (!npath) {
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cifs_dbg(VFS, "%s: failed to convert path from utf16\n", __func__);
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return ERR_PTR(-EINVAL);
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}
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} else {
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npath = kstrdup(path, GFP_KERNEL);
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if (!npath)
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return ERR_PTR(-ENOMEM);
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}
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convert_delimiter(npath, '\\');
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return npath;
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}
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static inline bool cache_entry_expired(const struct cache_entry *ce)
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{
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struct timespec64 ts;
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ktime_get_coarse_real_ts64(&ts);
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return timespec64_compare(&ts, &ce->etime) >= 0;
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}
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static inline void free_tgts(struct cache_entry *ce)
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{
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struct cache_dfs_tgt *t, *n;
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list_for_each_entry_safe(t, n, &ce->tlist, list) {
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list_del(&t->list);
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kfree(t->name);
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kfree(t);
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}
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}
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static inline void flush_cache_ent(struct cache_entry *ce)
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{
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hlist_del_init(&ce->hlist);
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kfree(ce->path);
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free_tgts(ce);
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atomic_dec(&cache_count);
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kmem_cache_free(cache_slab, ce);
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}
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static void flush_cache_ents(void)
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{
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int i;
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for (i = 0; i < CACHE_HTABLE_SIZE; i++) {
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struct hlist_head *l = &cache_htable[i];
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struct hlist_node *n;
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struct cache_entry *ce;
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hlist_for_each_entry_safe(ce, n, l, hlist) {
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if (!hlist_unhashed(&ce->hlist))
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flush_cache_ent(ce);
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}
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}
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}
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/*
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* dfs cache /proc file
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*/
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static int dfscache_proc_show(struct seq_file *m, void *v)
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{
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int i;
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struct cache_entry *ce;
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struct cache_dfs_tgt *t;
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seq_puts(m, "DFS cache\n---------\n");
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down_read(&htable_rw_lock);
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for (i = 0; i < CACHE_HTABLE_SIZE; i++) {
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struct hlist_head *l = &cache_htable[i];
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hlist_for_each_entry(ce, l, hlist) {
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if (hlist_unhashed(&ce->hlist))
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continue;
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seq_printf(m,
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"cache entry: path=%s,type=%s,ttl=%d,etime=%ld,hdr_flags=0x%x,ref_flags=0x%x,interlink=%s,path_consumed=%d,expired=%s\n",
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ce->path, ce->srvtype == DFS_TYPE_ROOT ? "root" : "link",
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ce->ttl, ce->etime.tv_nsec, ce->hdr_flags, ce->ref_flags,
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IS_DFS_INTERLINK(ce->hdr_flags) ? "yes" : "no",
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ce->path_consumed, cache_entry_expired(ce) ? "yes" : "no");
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list_for_each_entry(t, &ce->tlist, list) {
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seq_printf(m, " %s%s\n",
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t->name,
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READ_ONCE(ce->tgthint) == t ? " (target hint)" : "");
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}
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}
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}
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up_read(&htable_rw_lock);
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return 0;
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}
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static ssize_t dfscache_proc_write(struct file *file, const char __user *buffer,
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size_t count, loff_t *ppos)
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{
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char c;
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int rc;
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rc = get_user(c, buffer);
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if (rc)
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return rc;
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if (c != '0')
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return -EINVAL;
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cifs_dbg(FYI, "clearing dfs cache\n");
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down_write(&htable_rw_lock);
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flush_cache_ents();
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up_write(&htable_rw_lock);
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return count;
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}
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static int dfscache_proc_open(struct inode *inode, struct file *file)
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{
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return single_open(file, dfscache_proc_show, NULL);
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}
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const struct proc_ops dfscache_proc_ops = {
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.proc_open = dfscache_proc_open,
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.proc_read = seq_read,
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.proc_lseek = seq_lseek,
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.proc_release = single_release,
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.proc_write = dfscache_proc_write,
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};
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#ifdef CONFIG_CIFS_DEBUG2
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static inline void dump_tgts(const struct cache_entry *ce)
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{
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struct cache_dfs_tgt *t;
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cifs_dbg(FYI, "target list:\n");
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list_for_each_entry(t, &ce->tlist, list) {
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cifs_dbg(FYI, " %s%s\n", t->name,
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READ_ONCE(ce->tgthint) == t ? " (target hint)" : "");
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}
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}
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static inline void dump_ce(const struct cache_entry *ce)
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{
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cifs_dbg(FYI, "cache entry: path=%s,type=%s,ttl=%d,etime=%ld,hdr_flags=0x%x,ref_flags=0x%x,interlink=%s,path_consumed=%d,expired=%s\n",
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ce->path,
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ce->srvtype == DFS_TYPE_ROOT ? "root" : "link", ce->ttl,
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ce->etime.tv_nsec,
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ce->hdr_flags, ce->ref_flags,
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IS_DFS_INTERLINK(ce->hdr_flags) ? "yes" : "no",
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ce->path_consumed,
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cache_entry_expired(ce) ? "yes" : "no");
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dump_tgts(ce);
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}
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static inline void dump_refs(const struct dfs_info3_param *refs, int numrefs)
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{
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int i;
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cifs_dbg(FYI, "DFS referrals returned by the server:\n");
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for (i = 0; i < numrefs; i++) {
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const struct dfs_info3_param *ref = &refs[i];
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cifs_dbg(FYI,
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"\n"
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"flags: 0x%x\n"
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"path_consumed: %d\n"
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"server_type: 0x%x\n"
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"ref_flag: 0x%x\n"
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"path_name: %s\n"
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"node_name: %s\n"
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"ttl: %d (%dm)\n",
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ref->flags, ref->path_consumed, ref->server_type,
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ref->ref_flag, ref->path_name, ref->node_name,
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ref->ttl, ref->ttl / 60);
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}
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}
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#else
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#define dump_tgts(e)
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#define dump_ce(e)
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#define dump_refs(r, n)
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#endif
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/**
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* dfs_cache_init - Initialize DFS referral cache.
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*
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* Return zero if initialized successfully, otherwise non-zero.
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*/
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int dfs_cache_init(void)
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{
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int rc;
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int i;
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dfscache_wq = alloc_workqueue("cifs-dfscache", WQ_FREEZABLE | WQ_UNBOUND, 1);
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if (!dfscache_wq)
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return -ENOMEM;
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cache_slab = kmem_cache_create("cifs_dfs_cache",
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sizeof(struct cache_entry), 0,
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SLAB_HWCACHE_ALIGN, NULL);
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if (!cache_slab) {
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rc = -ENOMEM;
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goto out_destroy_wq;
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}
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for (i = 0; i < CACHE_HTABLE_SIZE; i++)
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INIT_HLIST_HEAD(&cache_htable[i]);
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atomic_set(&cache_count, 0);
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cache_cp = load_nls("utf8");
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if (!cache_cp)
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cache_cp = load_nls_default();
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cifs_dbg(FYI, "%s: initialized DFS referral cache\n", __func__);
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return 0;
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out_destroy_wq:
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destroy_workqueue(dfscache_wq);
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return rc;
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}
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static int cache_entry_hash(const void *data, int size, unsigned int *hash)
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{
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int i, clen;
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const unsigned char *s = data;
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wchar_t c;
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unsigned int h = 0;
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for (i = 0; i < size; i += clen) {
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clen = cache_cp->char2uni(&s[i], size - i, &c);
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if (unlikely(clen < 0)) {
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cifs_dbg(VFS, "%s: can't convert char\n", __func__);
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return clen;
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}
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c = cifs_toupper(c);
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h = jhash(&c, sizeof(c), h);
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}
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*hash = h % CACHE_HTABLE_SIZE;
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return 0;
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}
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/* Return target hint of a DFS cache entry */
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static inline char *get_tgt_name(const struct cache_entry *ce)
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{
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struct cache_dfs_tgt *t = READ_ONCE(ce->tgthint);
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return t ? t->name : ERR_PTR(-ENOENT);
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}
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/* Return expire time out of a new entry's TTL */
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static inline struct timespec64 get_expire_time(int ttl)
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{
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struct timespec64 ts = {
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.tv_sec = ttl,
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.tv_nsec = 0,
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};
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struct timespec64 now;
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ktime_get_coarse_real_ts64(&now);
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return timespec64_add(now, ts);
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}
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/* Allocate a new DFS target */
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static struct cache_dfs_tgt *alloc_target(const char *name, int path_consumed)
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{
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struct cache_dfs_tgt *t;
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t = kmalloc(sizeof(*t), GFP_ATOMIC);
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if (!t)
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return ERR_PTR(-ENOMEM);
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t->name = kstrdup(name, GFP_ATOMIC);
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if (!t->name) {
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kfree(t);
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return ERR_PTR(-ENOMEM);
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}
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t->path_consumed = path_consumed;
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INIT_LIST_HEAD(&t->list);
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return t;
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}
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/*
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* Copy DFS referral information to a cache entry and conditionally update
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* target hint.
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*/
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static int copy_ref_data(const struct dfs_info3_param *refs, int numrefs,
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struct cache_entry *ce, const char *tgthint)
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{
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struct cache_dfs_tgt *target;
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int i;
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ce->ttl = max_t(int, refs[0].ttl, CACHE_MIN_TTL);
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ce->etime = get_expire_time(ce->ttl);
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ce->srvtype = refs[0].server_type;
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ce->hdr_flags = refs[0].flags;
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ce->ref_flags = refs[0].ref_flag;
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ce->path_consumed = refs[0].path_consumed;
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for (i = 0; i < numrefs; i++) {
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struct cache_dfs_tgt *t;
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t = alloc_target(refs[i].node_name, refs[i].path_consumed);
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if (IS_ERR(t)) {
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free_tgts(ce);
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return PTR_ERR(t);
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}
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if (tgthint && !strcasecmp(t->name, tgthint)) {
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list_add(&t->list, &ce->tlist);
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tgthint = NULL;
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} else {
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list_add_tail(&t->list, &ce->tlist);
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}
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ce->numtgts++;
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}
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target = list_first_entry_or_null(&ce->tlist, struct cache_dfs_tgt,
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list);
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WRITE_ONCE(ce->tgthint, target);
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return 0;
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}
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/* Allocate a new cache entry */
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static struct cache_entry *alloc_cache_entry(struct dfs_info3_param *refs, int numrefs)
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{
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struct cache_entry *ce;
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int rc;
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ce = kmem_cache_zalloc(cache_slab, GFP_KERNEL);
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if (!ce)
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return ERR_PTR(-ENOMEM);
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ce->path = refs[0].path_name;
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refs[0].path_name = NULL;
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INIT_HLIST_NODE(&ce->hlist);
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INIT_LIST_HEAD(&ce->tlist);
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rc = copy_ref_data(refs, numrefs, ce, NULL);
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if (rc) {
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kfree(ce->path);
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kmem_cache_free(cache_slab, ce);
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ce = ERR_PTR(rc);
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}
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return ce;
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}
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static void remove_oldest_entry_locked(void)
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{
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int i;
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struct cache_entry *ce;
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struct cache_entry *to_del = NULL;
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WARN_ON(!rwsem_is_locked(&htable_rw_lock));
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for (i = 0; i < CACHE_HTABLE_SIZE; i++) {
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struct hlist_head *l = &cache_htable[i];
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hlist_for_each_entry(ce, l, hlist) {
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if (hlist_unhashed(&ce->hlist))
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continue;
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if (!to_del || timespec64_compare(&ce->etime,
|
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&to_del->etime) < 0)
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to_del = ce;
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}
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}
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|
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if (!to_del) {
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cifs_dbg(FYI, "%s: no entry to remove\n", __func__);
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return;
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}
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cifs_dbg(FYI, "%s: removing entry\n", __func__);
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dump_ce(to_del);
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flush_cache_ent(to_del);
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}
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/* Add a new DFS cache entry */
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static struct cache_entry *add_cache_entry_locked(struct dfs_info3_param *refs,
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int numrefs)
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{
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int rc;
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struct cache_entry *ce;
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unsigned int hash;
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|
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WARN_ON(!rwsem_is_locked(&htable_rw_lock));
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if (atomic_read(&cache_count) >= CACHE_MAX_ENTRIES) {
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cifs_dbg(FYI, "%s: reached max cache size (%d)\n", __func__, CACHE_MAX_ENTRIES);
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remove_oldest_entry_locked();
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}
|
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|
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rc = cache_entry_hash(refs[0].path_name, strlen(refs[0].path_name), &hash);
|
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if (rc)
|
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return ERR_PTR(rc);
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|
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ce = alloc_cache_entry(refs, numrefs);
|
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if (IS_ERR(ce))
|
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return ce;
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|
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spin_lock(&cache_ttl_lock);
|
|
if (!cache_ttl) {
|
|
cache_ttl = ce->ttl;
|
|
queue_delayed_work(dfscache_wq, &refresh_task, cache_ttl * HZ);
|
|
} else {
|
|
cache_ttl = min_t(int, cache_ttl, ce->ttl);
|
|
mod_delayed_work(dfscache_wq, &refresh_task, cache_ttl * HZ);
|
|
}
|
|
spin_unlock(&cache_ttl_lock);
|
|
|
|
hlist_add_head(&ce->hlist, &cache_htable[hash]);
|
|
dump_ce(ce);
|
|
|
|
atomic_inc(&cache_count);
|
|
|
|
return ce;
|
|
}
|
|
|
|
/* Check if two DFS paths are equal. @s1 and @s2 are expected to be in @cache_cp's charset */
|
|
static bool dfs_path_equal(const char *s1, int len1, const char *s2, int len2)
|
|
{
|
|
int i, l1, l2;
|
|
wchar_t c1, c2;
|
|
|
|
if (len1 != len2)
|
|
return false;
|
|
|
|
for (i = 0; i < len1; i += l1) {
|
|
l1 = cache_cp->char2uni(&s1[i], len1 - i, &c1);
|
|
l2 = cache_cp->char2uni(&s2[i], len2 - i, &c2);
|
|
if (unlikely(l1 < 0 && l2 < 0)) {
|
|
if (s1[i] != s2[i])
|
|
return false;
|
|
l1 = 1;
|
|
continue;
|
|
}
|
|
if (l1 != l2)
|
|
return false;
|
|
if (cifs_toupper(c1) != cifs_toupper(c2))
|
|
return false;
|
|
}
|
|
return true;
|
|
}
|
|
|
|
static struct cache_entry *__lookup_cache_entry(const char *path, unsigned int hash, int len)
|
|
{
|
|
struct cache_entry *ce;
|
|
|
|
hlist_for_each_entry(ce, &cache_htable[hash], hlist) {
|
|
if (dfs_path_equal(ce->path, strlen(ce->path), path, len)) {
|
|
dump_ce(ce);
|
|
return ce;
|
|
}
|
|
}
|
|
return ERR_PTR(-ENOENT);
|
|
}
|
|
|
|
/*
|
|
* Find a DFS cache entry in hash table and optionally check prefix path against normalized @path.
|
|
*
|
|
* Use whole path components in the match. Must be called with htable_rw_lock held.
|
|
*
|
|
* Return cached entry if successful.
|
|
* Return ERR_PTR(-ENOENT) if the entry is not found.
|
|
* Return error ptr otherwise.
|
|
*/
|
|
static struct cache_entry *lookup_cache_entry(const char *path)
|
|
{
|
|
struct cache_entry *ce;
|
|
int cnt = 0;
|
|
const char *s = path, *e;
|
|
char sep = *s;
|
|
unsigned int hash;
|
|
int rc;
|
|
|
|
while ((s = strchr(s, sep)) && ++cnt < 3)
|
|
s++;
|
|
|
|
if (cnt < 3) {
|
|
rc = cache_entry_hash(path, strlen(path), &hash);
|
|
if (rc)
|
|
return ERR_PTR(rc);
|
|
return __lookup_cache_entry(path, hash, strlen(path));
|
|
}
|
|
/*
|
|
* Handle paths that have more than two path components and are a complete prefix of the DFS
|
|
* referral request path (@path).
|
|
*
|
|
* See MS-DFSC 3.2.5.5 "Receiving a Root Referral Request or Link Referral Request".
|
|
*/
|
|
e = path + strlen(path) - 1;
|
|
while (e > s) {
|
|
int len;
|
|
|
|
/* skip separators */
|
|
while (e > s && *e == sep)
|
|
e--;
|
|
if (e == s)
|
|
break;
|
|
|
|
len = e + 1 - path;
|
|
rc = cache_entry_hash(path, len, &hash);
|
|
if (rc)
|
|
return ERR_PTR(rc);
|
|
ce = __lookup_cache_entry(path, hash, len);
|
|
if (!IS_ERR(ce))
|
|
return ce;
|
|
|
|
/* backward until separator */
|
|
while (e > s && *e != sep)
|
|
e--;
|
|
}
|
|
return ERR_PTR(-ENOENT);
|
|
}
|
|
|
|
/**
|
|
* dfs_cache_destroy - destroy DFS referral cache
|
|
*/
|
|
void dfs_cache_destroy(void)
|
|
{
|
|
cancel_delayed_work_sync(&refresh_task);
|
|
unload_nls(cache_cp);
|
|
flush_cache_ents();
|
|
kmem_cache_destroy(cache_slab);
|
|
destroy_workqueue(dfscache_wq);
|
|
|
|
cifs_dbg(FYI, "%s: destroyed DFS referral cache\n", __func__);
|
|
}
|
|
|
|
/* Update a cache entry with the new referral in @refs */
|
|
static int update_cache_entry_locked(struct cache_entry *ce, const struct dfs_info3_param *refs,
|
|
int numrefs)
|
|
{
|
|
struct cache_dfs_tgt *target;
|
|
char *th = NULL;
|
|
int rc;
|
|
|
|
WARN_ON(!rwsem_is_locked(&htable_rw_lock));
|
|
|
|
target = READ_ONCE(ce->tgthint);
|
|
if (target) {
|
|
th = kstrdup(target->name, GFP_ATOMIC);
|
|
if (!th)
|
|
return -ENOMEM;
|
|
}
|
|
|
|
free_tgts(ce);
|
|
ce->numtgts = 0;
|
|
|
|
rc = copy_ref_data(refs, numrefs, ce, th);
|
|
|
|
kfree(th);
|
|
|
|
return rc;
|
|
}
|
|
|
|
static int get_dfs_referral(const unsigned int xid, struct cifs_ses *ses, const char *path,
|
|
struct dfs_info3_param **refs, int *numrefs)
|
|
{
|
|
int rc;
|
|
int i;
|
|
|
|
*refs = NULL;
|
|
*numrefs = 0;
|
|
|
|
if (!ses || !ses->server || !ses->server->ops->get_dfs_refer)
|
|
return -EOPNOTSUPP;
|
|
if (unlikely(!cache_cp))
|
|
return -EINVAL;
|
|
|
|
cifs_dbg(FYI, "%s: ipc=%s referral=%s\n", __func__, ses->tcon_ipc->tree_name, path);
|
|
rc = ses->server->ops->get_dfs_refer(xid, ses, path, refs, numrefs, cache_cp,
|
|
NO_MAP_UNI_RSVD);
|
|
if (!rc) {
|
|
struct dfs_info3_param *ref = *refs;
|
|
|
|
for (i = 0; i < *numrefs; i++)
|
|
convert_delimiter(ref[i].path_name, '\\');
|
|
}
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
* Find, create or update a DFS cache entry.
|
|
*
|
|
* If the entry wasn't found, it will create a new one. Or if it was found but
|
|
* expired, then it will update the entry accordingly.
|
|
*
|
|
* For interlinks, cifs_mount() and expand_dfs_referral() are supposed to
|
|
* handle them properly.
|
|
*
|
|
* On success, return entry with acquired lock for reading, otherwise error ptr.
|
|
*/
|
|
static struct cache_entry *cache_refresh_path(const unsigned int xid,
|
|
struct cifs_ses *ses,
|
|
const char *path,
|
|
bool force_refresh)
|
|
{
|
|
struct dfs_info3_param *refs = NULL;
|
|
struct cache_entry *ce;
|
|
int numrefs = 0;
|
|
int rc;
|
|
|
|
cifs_dbg(FYI, "%s: search path: %s\n", __func__, path);
|
|
|
|
down_read(&htable_rw_lock);
|
|
|
|
ce = lookup_cache_entry(path);
|
|
if (!IS_ERR(ce)) {
|
|
if (!force_refresh && !cache_entry_expired(ce))
|
|
return ce;
|
|
} else if (PTR_ERR(ce) != -ENOENT) {
|
|
up_read(&htable_rw_lock);
|
|
return ce;
|
|
}
|
|
|
|
/*
|
|
* Unlock shared access as we don't want to hold any locks while getting
|
|
* a new referral. The @ses used for performing the I/O could be
|
|
* reconnecting and it acquires @htable_rw_lock to look up the dfs cache
|
|
* in order to failover -- if necessary.
|
|
*/
|
|
up_read(&htable_rw_lock);
|
|
|
|
/*
|
|
* Either the entry was not found, or it is expired, or it is a forced
|
|
* refresh.
|
|
* Request a new DFS referral in order to create or update a cache entry.
|
|
*/
|
|
rc = get_dfs_referral(xid, ses, path, &refs, &numrefs);
|
|
if (rc) {
|
|
ce = ERR_PTR(rc);
|
|
goto out;
|
|
}
|
|
|
|
dump_refs(refs, numrefs);
|
|
|
|
down_write(&htable_rw_lock);
|
|
/* Re-check as another task might have it added or refreshed already */
|
|
ce = lookup_cache_entry(path);
|
|
if (!IS_ERR(ce)) {
|
|
if (force_refresh || cache_entry_expired(ce)) {
|
|
rc = update_cache_entry_locked(ce, refs, numrefs);
|
|
if (rc)
|
|
ce = ERR_PTR(rc);
|
|
}
|
|
} else if (PTR_ERR(ce) == -ENOENT) {
|
|
ce = add_cache_entry_locked(refs, numrefs);
|
|
}
|
|
|
|
if (IS_ERR(ce)) {
|
|
up_write(&htable_rw_lock);
|
|
goto out;
|
|
}
|
|
|
|
downgrade_write(&htable_rw_lock);
|
|
out:
|
|
free_dfs_info_array(refs, numrefs);
|
|
return ce;
|
|
}
|
|
|
|
/*
|
|
* Set up a DFS referral from a given cache entry.
|
|
*
|
|
* Must be called with htable_rw_lock held.
|
|
*/
|
|
static int setup_referral(const char *path, struct cache_entry *ce,
|
|
struct dfs_info3_param *ref, const char *target)
|
|
{
|
|
int rc;
|
|
|
|
cifs_dbg(FYI, "%s: set up new ref\n", __func__);
|
|
|
|
memset(ref, 0, sizeof(*ref));
|
|
|
|
ref->path_name = kstrdup(path, GFP_ATOMIC);
|
|
if (!ref->path_name)
|
|
return -ENOMEM;
|
|
|
|
ref->node_name = kstrdup(target, GFP_ATOMIC);
|
|
if (!ref->node_name) {
|
|
rc = -ENOMEM;
|
|
goto err_free_path;
|
|
}
|
|
|
|
ref->path_consumed = ce->path_consumed;
|
|
ref->ttl = ce->ttl;
|
|
ref->server_type = ce->srvtype;
|
|
ref->ref_flag = ce->ref_flags;
|
|
ref->flags = ce->hdr_flags;
|
|
|
|
return 0;
|
|
|
|
err_free_path:
|
|
kfree(ref->path_name);
|
|
ref->path_name = NULL;
|
|
return rc;
|
|
}
|
|
|
|
/* Return target list of a DFS cache entry */
|
|
static int get_targets(struct cache_entry *ce, struct dfs_cache_tgt_list *tl)
|
|
{
|
|
int rc;
|
|
struct list_head *head = &tl->tl_list;
|
|
struct cache_dfs_tgt *t;
|
|
struct dfs_cache_tgt_iterator *it, *nit;
|
|
|
|
memset(tl, 0, sizeof(*tl));
|
|
INIT_LIST_HEAD(head);
|
|
|
|
list_for_each_entry(t, &ce->tlist, list) {
|
|
it = kzalloc(sizeof(*it), GFP_ATOMIC);
|
|
if (!it) {
|
|
rc = -ENOMEM;
|
|
goto err_free_it;
|
|
}
|
|
|
|
it->it_name = kstrdup(t->name, GFP_ATOMIC);
|
|
if (!it->it_name) {
|
|
kfree(it);
|
|
rc = -ENOMEM;
|
|
goto err_free_it;
|
|
}
|
|
it->it_path_consumed = t->path_consumed;
|
|
|
|
if (READ_ONCE(ce->tgthint) == t)
|
|
list_add(&it->it_list, head);
|
|
else
|
|
list_add_tail(&it->it_list, head);
|
|
}
|
|
|
|
tl->tl_numtgts = ce->numtgts;
|
|
|
|
return 0;
|
|
|
|
err_free_it:
|
|
list_for_each_entry_safe(it, nit, head, it_list) {
|
|
list_del(&it->it_list);
|
|
kfree(it->it_name);
|
|
kfree(it);
|
|
}
|
|
return rc;
|
|
}
|
|
|
|
/**
|
|
* dfs_cache_find - find a DFS cache entry
|
|
*
|
|
* If it doesn't find the cache entry, then it will get a DFS referral
|
|
* for @path and create a new entry.
|
|
*
|
|
* In case the cache entry exists but expired, it will get a DFS referral
|
|
* for @path and then update the respective cache entry.
|
|
*
|
|
* These parameters are passed down to the get_dfs_refer() call if it
|
|
* needs to be issued:
|
|
* @xid: syscall xid
|
|
* @ses: smb session to issue the request on
|
|
* @cp: codepage
|
|
* @remap: path character remapping type
|
|
* @path: path to lookup in DFS referral cache.
|
|
*
|
|
* @ref: when non-NULL, store single DFS referral result in it.
|
|
* @tgt_list: when non-NULL, store complete DFS target list in it.
|
|
*
|
|
* Return zero if the target was found, otherwise non-zero.
|
|
*/
|
|
int dfs_cache_find(const unsigned int xid, struct cifs_ses *ses, const struct nls_table *cp,
|
|
int remap, const char *path, struct dfs_info3_param *ref,
|
|
struct dfs_cache_tgt_list *tgt_list)
|
|
{
|
|
int rc;
|
|
const char *npath;
|
|
struct cache_entry *ce;
|
|
|
|
npath = dfs_cache_canonical_path(path, cp, remap);
|
|
if (IS_ERR(npath))
|
|
return PTR_ERR(npath);
|
|
|
|
ce = cache_refresh_path(xid, ses, npath, false);
|
|
if (IS_ERR(ce)) {
|
|
rc = PTR_ERR(ce);
|
|
goto out_free_path;
|
|
}
|
|
|
|
if (ref)
|
|
rc = setup_referral(path, ce, ref, get_tgt_name(ce));
|
|
else
|
|
rc = 0;
|
|
if (!rc && tgt_list)
|
|
rc = get_targets(ce, tgt_list);
|
|
|
|
up_read(&htable_rw_lock);
|
|
|
|
out_free_path:
|
|
kfree(npath);
|
|
return rc;
|
|
}
|
|
|
|
/**
|
|
* dfs_cache_noreq_find - find a DFS cache entry without sending any requests to
|
|
* the currently connected server.
|
|
*
|
|
* NOTE: This function will neither update a cache entry in case it was
|
|
* expired, nor create a new cache entry if @path hasn't been found. It heavily
|
|
* relies on an existing cache entry.
|
|
*
|
|
* @path: canonical DFS path to lookup in the DFS referral cache.
|
|
* @ref: when non-NULL, store single DFS referral result in it.
|
|
* @tgt_list: when non-NULL, store complete DFS target list in it.
|
|
*
|
|
* Return 0 if successful.
|
|
* Return -ENOENT if the entry was not found.
|
|
* Return non-zero for other errors.
|
|
*/
|
|
int dfs_cache_noreq_find(const char *path, struct dfs_info3_param *ref,
|
|
struct dfs_cache_tgt_list *tgt_list)
|
|
{
|
|
int rc;
|
|
struct cache_entry *ce;
|
|
|
|
cifs_dbg(FYI, "%s: path: %s\n", __func__, path);
|
|
|
|
down_read(&htable_rw_lock);
|
|
|
|
ce = lookup_cache_entry(path);
|
|
if (IS_ERR(ce)) {
|
|
rc = PTR_ERR(ce);
|
|
goto out_unlock;
|
|
}
|
|
|
|
if (ref)
|
|
rc = setup_referral(path, ce, ref, get_tgt_name(ce));
|
|
else
|
|
rc = 0;
|
|
if (!rc && tgt_list)
|
|
rc = get_targets(ce, tgt_list);
|
|
|
|
out_unlock:
|
|
up_read(&htable_rw_lock);
|
|
return rc;
|
|
}
|
|
|
|
/**
|
|
* dfs_cache_noreq_update_tgthint - update target hint of a DFS cache entry
|
|
* without sending any requests to the currently connected server.
|
|
*
|
|
* NOTE: This function will neither update a cache entry in case it was
|
|
* expired, nor create a new cache entry if @path hasn't been found. It heavily
|
|
* relies on an existing cache entry.
|
|
*
|
|
* @path: canonical DFS path to lookup in DFS referral cache.
|
|
* @it: target iterator which contains the target hint to update the cache
|
|
* entry with.
|
|
*
|
|
* Return zero if the target hint was updated successfully, otherwise non-zero.
|
|
*/
|
|
void dfs_cache_noreq_update_tgthint(const char *path, const struct dfs_cache_tgt_iterator *it)
|
|
{
|
|
struct cache_dfs_tgt *t;
|
|
struct cache_entry *ce;
|
|
|
|
if (!path || !it)
|
|
return;
|
|
|
|
cifs_dbg(FYI, "%s: path: %s\n", __func__, path);
|
|
|
|
down_read(&htable_rw_lock);
|
|
|
|
ce = lookup_cache_entry(path);
|
|
if (IS_ERR(ce))
|
|
goto out_unlock;
|
|
|
|
t = READ_ONCE(ce->tgthint);
|
|
|
|
if (unlikely(!strcasecmp(it->it_name, t->name)))
|
|
goto out_unlock;
|
|
|
|
list_for_each_entry(t, &ce->tlist, list) {
|
|
if (!strcasecmp(t->name, it->it_name)) {
|
|
WRITE_ONCE(ce->tgthint, t);
|
|
cifs_dbg(FYI, "%s: new target hint: %s\n", __func__,
|
|
it->it_name);
|
|
break;
|
|
}
|
|
}
|
|
|
|
out_unlock:
|
|
up_read(&htable_rw_lock);
|
|
}
|
|
|
|
/**
|
|
* dfs_cache_get_tgt_referral - returns a DFS referral (@ref) from a given
|
|
* target iterator (@it).
|
|
*
|
|
* @path: canonical DFS path to lookup in DFS referral cache.
|
|
* @it: DFS target iterator.
|
|
* @ref: DFS referral pointer to set up the gathered information.
|
|
*
|
|
* Return zero if the DFS referral was set up correctly, otherwise non-zero.
|
|
*/
|
|
int dfs_cache_get_tgt_referral(const char *path, const struct dfs_cache_tgt_iterator *it,
|
|
struct dfs_info3_param *ref)
|
|
{
|
|
int rc;
|
|
struct cache_entry *ce;
|
|
|
|
if (!it || !ref)
|
|
return -EINVAL;
|
|
|
|
cifs_dbg(FYI, "%s: path: %s\n", __func__, path);
|
|
|
|
down_read(&htable_rw_lock);
|
|
|
|
ce = lookup_cache_entry(path);
|
|
if (IS_ERR(ce)) {
|
|
rc = PTR_ERR(ce);
|
|
goto out_unlock;
|
|
}
|
|
|
|
cifs_dbg(FYI, "%s: target name: %s\n", __func__, it->it_name);
|
|
|
|
rc = setup_referral(path, ce, ref, it->it_name);
|
|
|
|
out_unlock:
|
|
up_read(&htable_rw_lock);
|
|
return rc;
|
|
}
|
|
|
|
/* Extract share from DFS target and return a pointer to prefix path or NULL */
|
|
static const char *parse_target_share(const char *target, char **share)
|
|
{
|
|
const char *s, *seps = "/\\";
|
|
size_t len;
|
|
|
|
s = strpbrk(target + 1, seps);
|
|
if (!s)
|
|
return ERR_PTR(-EINVAL);
|
|
|
|
len = strcspn(s + 1, seps);
|
|
if (!len)
|
|
return ERR_PTR(-EINVAL);
|
|
s += len;
|
|
|
|
len = s - target + 1;
|
|
*share = kstrndup(target, len, GFP_KERNEL);
|
|
if (!*share)
|
|
return ERR_PTR(-ENOMEM);
|
|
|
|
s = target + len;
|
|
return s + strspn(s, seps);
|
|
}
|
|
|
|
/**
|
|
* dfs_cache_get_tgt_share - parse a DFS target
|
|
*
|
|
* @path: DFS full path
|
|
* @it: DFS target iterator.
|
|
* @share: tree name.
|
|
* @prefix: prefix path.
|
|
*
|
|
* Return zero if target was parsed correctly, otherwise non-zero.
|
|
*/
|
|
int dfs_cache_get_tgt_share(char *path, const struct dfs_cache_tgt_iterator *it, char **share,
|
|
char **prefix)
|
|
{
|
|
char sep;
|
|
char *target_share;
|
|
char *ppath = NULL;
|
|
const char *target_ppath, *dfsref_ppath;
|
|
size_t target_pplen, dfsref_pplen;
|
|
size_t len, c;
|
|
|
|
if (!it || !path || !share || !prefix || strlen(path) < it->it_path_consumed)
|
|
return -EINVAL;
|
|
|
|
sep = it->it_name[0];
|
|
if (sep != '\\' && sep != '/')
|
|
return -EINVAL;
|
|
|
|
target_ppath = parse_target_share(it->it_name, &target_share);
|
|
if (IS_ERR(target_ppath))
|
|
return PTR_ERR(target_ppath);
|
|
|
|
/* point to prefix in DFS referral path */
|
|
dfsref_ppath = path + it->it_path_consumed;
|
|
dfsref_ppath += strspn(dfsref_ppath, "/\\");
|
|
|
|
target_pplen = strlen(target_ppath);
|
|
dfsref_pplen = strlen(dfsref_ppath);
|
|
|
|
/* merge prefix paths from DFS referral path and target node */
|
|
if (target_pplen || dfsref_pplen) {
|
|
len = target_pplen + dfsref_pplen + 2;
|
|
ppath = kzalloc(len, GFP_KERNEL);
|
|
if (!ppath) {
|
|
kfree(target_share);
|
|
return -ENOMEM;
|
|
}
|
|
c = strscpy(ppath, target_ppath, len);
|
|
if (c && dfsref_pplen)
|
|
ppath[c] = sep;
|
|
strlcat(ppath, dfsref_ppath, len);
|
|
}
|
|
*share = target_share;
|
|
*prefix = ppath;
|
|
return 0;
|
|
}
|
|
|
|
static bool target_share_equal(struct TCP_Server_Info *server, const char *s1, const char *s2)
|
|
{
|
|
char unc[sizeof("\\\\") + SERVER_NAME_LENGTH] = {0};
|
|
const char *host;
|
|
size_t hostlen;
|
|
struct sockaddr_storage ss;
|
|
bool match;
|
|
int rc;
|
|
|
|
if (strcasecmp(s1, s2))
|
|
return false;
|
|
|
|
/*
|
|
* Resolve share's hostname and check if server address matches. Otherwise just ignore it
|
|
* as we could not have upcall to resolve hostname or failed to convert ip address.
|
|
*/
|
|
extract_unc_hostname(s1, &host, &hostlen);
|
|
scnprintf(unc, sizeof(unc), "\\\\%.*s", (int)hostlen, host);
|
|
|
|
rc = dns_resolve_server_name_to_ip(unc, (struct sockaddr *)&ss, NULL);
|
|
if (rc < 0) {
|
|
cifs_dbg(FYI, "%s: could not resolve %.*s. assuming server address matches.\n",
|
|
__func__, (int)hostlen, host);
|
|
return true;
|
|
}
|
|
|
|
cifs_server_lock(server);
|
|
match = cifs_match_ipaddr((struct sockaddr *)&server->dstaddr, (struct sockaddr *)&ss);
|
|
cifs_server_unlock(server);
|
|
|
|
return match;
|
|
}
|
|
|
|
/*
|
|
* Mark dfs tcon for reconnecting when the currently connected tcon does not match any of the new
|
|
* target shares in @refs.
|
|
*/
|
|
static void mark_for_reconnect_if_needed(struct TCP_Server_Info *server,
|
|
struct dfs_cache_tgt_list *old_tl,
|
|
struct dfs_cache_tgt_list *new_tl)
|
|
{
|
|
struct dfs_cache_tgt_iterator *oit, *nit;
|
|
|
|
for (oit = dfs_cache_get_tgt_iterator(old_tl); oit;
|
|
oit = dfs_cache_get_next_tgt(old_tl, oit)) {
|
|
for (nit = dfs_cache_get_tgt_iterator(new_tl); nit;
|
|
nit = dfs_cache_get_next_tgt(new_tl, nit)) {
|
|
if (target_share_equal(server,
|
|
dfs_cache_get_tgt_name(oit),
|
|
dfs_cache_get_tgt_name(nit)))
|
|
return;
|
|
}
|
|
}
|
|
|
|
cifs_dbg(FYI, "%s: no cached or matched targets. mark dfs share for reconnect.\n", __func__);
|
|
cifs_signal_cifsd_for_reconnect(server, true);
|
|
}
|
|
|
|
/* Refresh dfs referral of tcon and mark it for reconnect if needed */
|
|
static int __refresh_tcon(const char *path, struct cifs_tcon *tcon, bool force_refresh)
|
|
{
|
|
struct dfs_cache_tgt_list old_tl = DFS_CACHE_TGT_LIST_INIT(old_tl);
|
|
struct dfs_cache_tgt_list new_tl = DFS_CACHE_TGT_LIST_INIT(new_tl);
|
|
struct cifs_ses *ses = CIFS_DFS_ROOT_SES(tcon->ses);
|
|
struct cifs_tcon *ipc = ses->tcon_ipc;
|
|
bool needs_refresh = false;
|
|
struct cache_entry *ce;
|
|
unsigned int xid;
|
|
int rc = 0;
|
|
|
|
xid = get_xid();
|
|
|
|
down_read(&htable_rw_lock);
|
|
ce = lookup_cache_entry(path);
|
|
needs_refresh = force_refresh || IS_ERR(ce) || cache_entry_expired(ce);
|
|
if (!IS_ERR(ce)) {
|
|
rc = get_targets(ce, &old_tl);
|
|
cifs_dbg(FYI, "%s: get_targets: %d\n", __func__, rc);
|
|
}
|
|
up_read(&htable_rw_lock);
|
|
|
|
if (!needs_refresh) {
|
|
rc = 0;
|
|
goto out;
|
|
}
|
|
|
|
spin_lock(&ipc->tc_lock);
|
|
if (ipc->status != TID_GOOD) {
|
|
spin_unlock(&ipc->tc_lock);
|
|
cifs_dbg(FYI, "%s: skip cache refresh due to disconnected ipc\n", __func__);
|
|
goto out;
|
|
}
|
|
spin_unlock(&ipc->tc_lock);
|
|
|
|
ce = cache_refresh_path(xid, ses, path, true);
|
|
if (!IS_ERR(ce)) {
|
|
rc = get_targets(ce, &new_tl);
|
|
up_read(&htable_rw_lock);
|
|
cifs_dbg(FYI, "%s: get_targets: %d\n", __func__, rc);
|
|
mark_for_reconnect_if_needed(tcon->ses->server, &old_tl, &new_tl);
|
|
}
|
|
|
|
out:
|
|
free_xid(xid);
|
|
dfs_cache_free_tgts(&old_tl);
|
|
dfs_cache_free_tgts(&new_tl);
|
|
return rc;
|
|
}
|
|
|
|
static int refresh_tcon(struct cifs_tcon *tcon, bool force_refresh)
|
|
{
|
|
struct TCP_Server_Info *server = tcon->ses->server;
|
|
|
|
mutex_lock(&server->refpath_lock);
|
|
if (server->leaf_fullpath)
|
|
__refresh_tcon(server->leaf_fullpath + 1, tcon, force_refresh);
|
|
mutex_unlock(&server->refpath_lock);
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* dfs_cache_remount_fs - remount a DFS share
|
|
*
|
|
* Reconfigure dfs mount by forcing a new DFS referral and if the currently cached targets do not
|
|
* match any of the new targets, mark it for reconnect.
|
|
*
|
|
* @cifs_sb: cifs superblock.
|
|
*
|
|
* Return zero if remounted, otherwise non-zero.
|
|
*/
|
|
int dfs_cache_remount_fs(struct cifs_sb_info *cifs_sb)
|
|
{
|
|
struct cifs_tcon *tcon;
|
|
struct TCP_Server_Info *server;
|
|
|
|
if (!cifs_sb || !cifs_sb->master_tlink)
|
|
return -EINVAL;
|
|
|
|
tcon = cifs_sb_master_tcon(cifs_sb);
|
|
server = tcon->ses->server;
|
|
|
|
if (!server->origin_fullpath) {
|
|
cifs_dbg(FYI, "%s: not a dfs mount\n", __func__);
|
|
return 0;
|
|
}
|
|
/*
|
|
* After reconnecting to a different server, unique ids won't match anymore, so we disable
|
|
* serverino. This prevents dentry revalidation to think the dentry are stale (ESTALE).
|
|
*/
|
|
cifs_autodisable_serverino(cifs_sb);
|
|
/*
|
|
* Force the use of prefix path to support failover on DFS paths that resolve to targets
|
|
* that have different prefix paths.
|
|
*/
|
|
cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_USE_PREFIX_PATH;
|
|
|
|
return refresh_tcon(tcon, true);
|
|
}
|
|
|
|
/*
|
|
* Worker that will refresh DFS cache from all active mounts based on lowest TTL value
|
|
* from a DFS referral.
|
|
*/
|
|
static void refresh_cache_worker(struct work_struct *work)
|
|
{
|
|
struct TCP_Server_Info *server;
|
|
struct cifs_tcon *tcon, *ntcon;
|
|
struct list_head tcons;
|
|
struct cifs_ses *ses;
|
|
|
|
INIT_LIST_HEAD(&tcons);
|
|
|
|
spin_lock(&cifs_tcp_ses_lock);
|
|
list_for_each_entry(server, &cifs_tcp_ses_list, tcp_ses_list) {
|
|
if (!server->leaf_fullpath)
|
|
continue;
|
|
|
|
list_for_each_entry(ses, &server->smb_ses_list, smb_ses_list) {
|
|
if (ses->tcon_ipc) {
|
|
ses->ses_count++;
|
|
list_add_tail(&ses->tcon_ipc->ulist, &tcons);
|
|
}
|
|
list_for_each_entry(tcon, &ses->tcon_list, tcon_list) {
|
|
if (!tcon->ipc) {
|
|
tcon->tc_count++;
|
|
list_add_tail(&tcon->ulist, &tcons);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
spin_unlock(&cifs_tcp_ses_lock);
|
|
|
|
list_for_each_entry_safe(tcon, ntcon, &tcons, ulist) {
|
|
struct TCP_Server_Info *server = tcon->ses->server;
|
|
|
|
list_del_init(&tcon->ulist);
|
|
|
|
mutex_lock(&server->refpath_lock);
|
|
if (server->leaf_fullpath)
|
|
__refresh_tcon(server->leaf_fullpath + 1, tcon, false);
|
|
mutex_unlock(&server->refpath_lock);
|
|
|
|
if (tcon->ipc)
|
|
cifs_put_smb_ses(tcon->ses);
|
|
else
|
|
cifs_put_tcon(tcon);
|
|
}
|
|
|
|
spin_lock(&cache_ttl_lock);
|
|
queue_delayed_work(dfscache_wq, &refresh_task, cache_ttl * HZ);
|
|
spin_unlock(&cache_ttl_lock);
|
|
}
|