Commit 54be1f6c authored by Paulo Alcantara's avatar Paulo Alcantara Committed by Steve French

cifs: Add DFS cache routines

* Add new dfs_cache.[ch] files

* Add new /proc/fs/cifs/dfscache file
  - dump current cache when read
  - clear current cache when writing "0" to it

* Add delayed_work to periodically refresh cache entries

The new interface will be used for caching DFS referrals, as well as
supporting client target failover.

The DFS cache is a hashtable that maps UNC paths to cache entries.

A cache entry contains:
- the UNC path it is mapped on
- how much the the UNC path the entry consumes
- flags
- a Time-To-Live after which the entry expires
- a list of possible targets (linked lists of UNC paths)
- a "hint target" pointing the last known working target or the first
  target if none were tried. This hint lets cifs.ko remember and try
  working targets first.

* Looking for an entry in the cache is done with dfs_cache_find()
  - if no valid entries are found, a DFS query is made, stored in the
    cache and returned
  - the full target list can be copied and returned to avoid race
    conditions and looped on with the help with the
    dfs_cache_tgt_iterator

* Updating the target hint to the next target is done with
  dfs_cache_update_tgthint()

These functions have a dfs_cache_noreq_XXX() version that doesn't
fetches referrals if no entries are found. These versions don't
require the tcp/ses/tcon/cifs_sb parameters as a result.

Expired entries cannot be used and since they have a pretty short TTL
[1] in order for them to be useful for failover the DFS cache adds a
delayed work called periodically to keep them fresh.

Since we might not have available connections to issue the referral
request when refreshing we need to store volume_info structs with
credentials and other needed info to be able to connect to the right
server.

1: Windows defaults: 5mn for domain-based referrals, 30mn for regular
links
Signed-off-by: default avatarPaulo Alcantara <palcantara@suse.de>
Signed-off-by: default avatarAurelien Aptel <aaptel@suse.com>
Signed-off-by: default avatarSteve French <stfrench@microsoft.com>
parent e7b602f4
......@@ -17,7 +17,7 @@ cifs-$(CONFIG_CIFS_ACL) += cifsacl.o
cifs-$(CONFIG_CIFS_UPCALL) += cifs_spnego.o
cifs-$(CONFIG_CIFS_DFS_UPCALL) += dns_resolve.o cifs_dfs_ref.o
cifs-$(CONFIG_CIFS_DFS_UPCALL) += dns_resolve.o cifs_dfs_ref.o dfs_cache.o
cifs-$(CONFIG_CIFS_FSCACHE) += fscache.o cache.o
......
......@@ -30,6 +30,9 @@
#include "cifsproto.h"
#include "cifs_debug.h"
#include "cifsfs.h"
#ifdef CONFIG_CIFS_DFS_UPCALL
#include "dfs_cache.h"
#endif
#ifdef CONFIG_CIFS_SMB_DIRECT
#include "smbdirect.h"
#endif
......@@ -629,6 +632,11 @@ cifs_proc_init(void)
&cifs_security_flags_proc_fops);
proc_create("LookupCacheEnabled", 0644, proc_fs_cifs,
&cifs_lookup_cache_proc_fops);
#ifdef CONFIG_CIFS_DFS_UPCALL
proc_create("dfscache", 0644, proc_fs_cifs, &dfscache_proc_fops);
#endif
#ifdef CONFIG_CIFS_SMB_DIRECT
proc_create("rdma_readwrite_threshold", 0644, proc_fs_cifs,
&cifs_rdma_readwrite_threshold_proc_fops);
......@@ -663,6 +671,10 @@ cifs_proc_clean(void)
remove_proc_entry("SecurityFlags", proc_fs_cifs);
remove_proc_entry("LinuxExtensionsEnabled", proc_fs_cifs);
remove_proc_entry("LookupCacheEnabled", proc_fs_cifs);
#ifdef CONFIG_CIFS_DFS_UPCALL
remove_proc_entry("dfscache", proc_fs_cifs);
#endif
#ifdef CONFIG_CIFS_SMB_DIRECT
remove_proc_entry("rdma_readwrite_threshold", proc_fs_cifs);
remove_proc_entry("smbd_max_frmr_depth", proc_fs_cifs);
......
......@@ -1014,6 +1014,11 @@ struct cifs_tcon {
struct list_head pending_opens; /* list of incomplete opens */
struct cached_fid crfid; /* Cached root fid */
/* BB add field for back pointer to sb struct(s)? */
#ifdef CONFIG_CIFS_DFS_UPCALL
char *dfs_path;
int remap:2;
struct list_head ulist; /* cache update list */
#endif
};
/*
......
......@@ -527,6 +527,9 @@ extern int SMBencrypt(unsigned char *passwd, const unsigned char *c8,
extern void
cifs_cleanup_volume_info_contents(struct smb_vol *volume_info);
extern struct TCP_Server_Info *
cifs_find_tcp_session(struct smb_vol *vol);
void cifs_readdata_release(struct kref *refcount);
int cifs_async_readv(struct cifs_readdata *rdata);
int cifs_readv_receive(struct TCP_Server_Info *server, struct mid_q_entry *mid);
......
......@@ -2295,7 +2295,7 @@ static int match_server(struct TCP_Server_Info *server, struct smb_vol *vol)
return 1;
}
static struct TCP_Server_Info *
struct TCP_Server_Info *
cifs_find_tcp_session(struct smb_vol *vol)
{
struct TCP_Server_Info *server;
......
// SPDX-License-Identifier: GPL-2.0
/*
* DFS referral cache routines
*
* Copyright (c) 2018 Paulo Alcantara <palcantara@suse.de>
*/
#include <linux/rcupdate.h>
#include <linux/rculist.h>
#include <linux/jhash.h>
#include <linux/ktime.h>
#include <linux/slab.h>
#include <linux/nls.h>
#include <linux/workqueue.h>
#include "cifsglob.h"
#include "smb2pdu.h"
#include "smb2proto.h"
#include "cifsproto.h"
#include "cifs_debug.h"
#include "cifs_unicode.h"
#include "smb2glob.h"
#include "dfs_cache.h"
#define DFS_CACHE_HTABLE_SIZE 32
#define DFS_CACHE_MAX_ENTRIES 64
#define IS_INTERLINK_SET(v) ((v) & (DFSREF_REFERRAL_SERVER | \
DFSREF_STORAGE_SERVER))
struct dfs_cache_tgt {
char *t_name;
struct list_head t_list;
};
struct dfs_cache_entry {
struct hlist_node ce_hlist;
const char *ce_path;
int ce_ttl;
int ce_srvtype;
int ce_flags;
struct timespec64 ce_etime;
int ce_path_consumed;
int ce_numtgts;
struct list_head ce_tlist;
struct dfs_cache_tgt *ce_tgthint;
struct rcu_head ce_rcu;
};
static struct kmem_cache *dfs_cache_slab __read_mostly;
struct dfs_cache_vol_info {
char *vi_fullpath;
struct smb_vol vi_vol;
struct list_head vi_list;
};
struct dfs_cache {
struct mutex dc_lock;
struct nls_table *dc_nlsc;
struct list_head dc_vol_list;
int dc_ttl;
struct delayed_work dc_refresh;
};
static struct dfs_cache dfs_cache;
/*
* Number of entries in the cache
*/
static size_t dfs_cache_count;
static DEFINE_MUTEX(dfs_cache_list_lock);
static struct hlist_head dfs_cache_htable[DFS_CACHE_HTABLE_SIZE];
static void refresh_cache_worker(struct work_struct *work);
static inline bool is_path_valid(const char *path)
{
return path && (strchr(path + 1, '\\') || strchr(path + 1, '/'));
}
static inline int get_normalized_path(const char *path, char **npath)
{
if (*path == '\\') {
*npath = (char *)path;
} else {
*npath = kstrndup(path, strlen(path), GFP_KERNEL);
if (!*npath)
return -ENOMEM;
convert_delimiter(*npath, '\\');
}
return 0;
}
static inline void free_normalized_path(const char *path, char *npath)
{
if (path != npath)
kfree(npath);
}
static inline bool cache_entry_expired(const struct dfs_cache_entry *ce)
{
struct timespec64 ts;
ts = current_kernel_time64();
return timespec64_compare(&ts, &ce->ce_etime) >= 0;
}
static inline void free_tgts(struct dfs_cache_entry *ce)
{
struct dfs_cache_tgt *t, *n;
list_for_each_entry_safe(t, n, &ce->ce_tlist, t_list) {
list_del(&t->t_list);
kfree(t->t_name);
kfree(t);
}
}
static void free_cache_entry(struct rcu_head *rcu)
{
struct dfs_cache_entry *ce = container_of(rcu, struct dfs_cache_entry,
ce_rcu);
kmem_cache_free(dfs_cache_slab, ce);
}
static inline void flush_cache_ent(struct dfs_cache_entry *ce)
{
if (hlist_unhashed(&ce->ce_hlist))
return;
hlist_del_init_rcu(&ce->ce_hlist);
kfree(ce->ce_path);
free_tgts(ce);
dfs_cache_count--;
call_rcu(&ce->ce_rcu, free_cache_entry);
}
static void flush_cache_ents(void)
{
int i;
rcu_read_lock();
for (i = 0; i < DFS_CACHE_HTABLE_SIZE; i++) {
struct hlist_head *l = &dfs_cache_htable[i];
struct dfs_cache_entry *ce;
hlist_for_each_entry_rcu(ce, l, ce_hlist)
flush_cache_ent(ce);
}
rcu_read_unlock();
}
/*
* dfs cache /proc file
*/
static int dfscache_proc_show(struct seq_file *m, void *v)
{
int bucket;
struct dfs_cache_entry *ce;
struct dfs_cache_tgt *t;
seq_puts(m, "DFS cache\n---------\n");
mutex_lock(&dfs_cache_list_lock);
rcu_read_lock();
hash_for_each_rcu(dfs_cache_htable, bucket, ce, ce_hlist) {
seq_printf(m,
"cache entry: path=%s,type=%s,ttl=%d,etime=%ld,"
"interlink=%s,path_consumed=%d,expired=%s\n",
ce->ce_path,
ce->ce_srvtype == DFS_TYPE_ROOT ? "root" : "link",
ce->ce_ttl, ce->ce_etime.tv_nsec,
IS_INTERLINK_SET(ce->ce_flags) ? "yes" : "no",
ce->ce_path_consumed,
cache_entry_expired(ce) ? "yes" : "no");
list_for_each_entry(t, &ce->ce_tlist, t_list) {
seq_printf(m, " %s%s\n",
t->t_name,
ce->ce_tgthint == t ? " (target hint)" : "");
}
}
rcu_read_unlock();
mutex_unlock(&dfs_cache_list_lock);
return 0;
}
static ssize_t dfscache_proc_write(struct file *file, const char __user *buffer,
size_t count, loff_t *ppos)
{
char c;
int rc;
rc = get_user(c, buffer);
if (rc)
return rc;
if (c != '0')
return -EINVAL;
cifs_dbg(FYI, "clearing dfs cache");
mutex_lock(&dfs_cache_list_lock);
flush_cache_ents();
mutex_unlock(&dfs_cache_list_lock);
return count;
}
static int dfscache_proc_open(struct inode *inode, struct file *file)
{
return single_open(file, dfscache_proc_show, NULL);
}
const struct file_operations dfscache_proc_fops = {
.open = dfscache_proc_open,
.read = seq_read,
.llseek = seq_lseek,
.release = single_release,
.write = dfscache_proc_write,
};
#ifdef CONFIG_CIFS_DEBUG2
static inline void dump_tgts(const struct dfs_cache_entry *ce)
{
struct dfs_cache_tgt *t;
cifs_dbg(FYI, "target list:\n");
list_for_each_entry(t, &ce->ce_tlist, t_list) {
cifs_dbg(FYI, " %s%s\n", t->t_name,
ce->ce_tgthint == t ? " (target hint)" : "");
}
}
static inline void dump_ce(const struct dfs_cache_entry *ce)
{
cifs_dbg(FYI, "cache entry: path=%s,type=%s,ttl=%d,etime=%ld,"
"interlink=%s,path_consumed=%d,expired=%s\n", ce->ce_path,
ce->ce_srvtype == DFS_TYPE_ROOT ? "root" : "link", ce->ce_ttl,
ce->ce_etime.tv_nsec,
IS_INTERLINK_SET(ce->ce_flags) ? "yes" : "no",
ce->ce_path_consumed,
cache_entry_expired(ce) ? "yes" : "no");
dump_tgts(ce);
}
static inline void dump_refs(const struct dfs_info3_param *refs, int numrefs)
{
int i;
cifs_dbg(FYI, "DFS referrals returned by the server:\n");
for (i = 0; i < numrefs; i++) {
const struct dfs_info3_param *ref = &refs[i];
cifs_dbg(FYI,
"\n"
"flags: 0x%x\n"
"path_consumed: %d\n"
"server_type: 0x%x\n"
"ref_flag: 0x%x\n"
"path_name: %s\n"
"node_name: %s\n"
"ttl: %d (%dm)\n",
ref->flags, ref->path_consumed, ref->server_type,
ref->ref_flag, ref->path_name, ref->node_name,
ref->ttl, ref->ttl / 60);
}
}
#else
#define dump_tgts(e)
#define dump_ce(e)
#define dump_refs(r, n)
#endif
/**
* dfs_cache_init - Initialize DFS referral cache.
*
* Return zero if initialized successfully, otherwise non-zero.
*/
int dfs_cache_init(void)
{
int i;
dfs_cache_slab = kmem_cache_create("cifs_dfs_cache",
sizeof(struct dfs_cache_entry), 0,
SLAB_HWCACHE_ALIGN, NULL);
if (!dfs_cache_slab)
return -ENOMEM;
for (i = 0; i < DFS_CACHE_HTABLE_SIZE; i++)
INIT_HLIST_HEAD(&dfs_cache_htable[i]);
INIT_LIST_HEAD(&dfs_cache.dc_vol_list);
mutex_init(&dfs_cache.dc_lock);
INIT_DELAYED_WORK(&dfs_cache.dc_refresh, refresh_cache_worker);
dfs_cache.dc_ttl = -1;
dfs_cache.dc_nlsc = load_nls_default();
cifs_dbg(FYI, "%s: initialized DFS referral cache\n", __func__);
return 0;
}
static inline unsigned int cache_entry_hash(const void *data, int size)
{
unsigned int h;
h = jhash(data, size, 0);
return h & (DFS_CACHE_HTABLE_SIZE - 1);
}
/* Check whether second path component of @path is SYSVOL or NETLOGON */
static inline bool is_sysvol_or_netlogon(const char *path)
{
const char *s;
char sep = path[0];
s = strchr(path + 1, sep) + 1;
return !strncasecmp(s, "sysvol", strlen("sysvol")) ||
!strncasecmp(s, "netlogon", strlen("netlogon"));
}
/* Return target hint of a DFS cache entry */
static inline char *get_tgt_name(const struct dfs_cache_entry *ce)
{
struct dfs_cache_tgt *t = ce->ce_tgthint;
return t ? t->t_name : ERR_PTR(-ENOENT);
}
/* Return expire time out of a new entry's TTL */
static inline struct timespec64 get_expire_time(int ttl)
{
struct timespec64 ts = {
.tv_sec = ttl,
.tv_nsec = 0,
};
return timespec64_add(current_kernel_time64(), ts);
}
/* Allocate a new DFS target */
static inline struct dfs_cache_tgt *alloc_tgt(const char *name)
{
struct dfs_cache_tgt *t;
t = kmalloc(sizeof(*t), GFP_KERNEL);
if (!t)
return ERR_PTR(-ENOMEM);
t->t_name = kstrndup(name, strlen(name), GFP_KERNEL);
if (!t->t_name) {
kfree(t);
return ERR_PTR(-ENOMEM);
}
INIT_LIST_HEAD(&t->t_list);
return t;
}
/*
* Copy DFS referral information to a cache entry and conditionally update
* target hint.
*/
static int copy_ref_data(const struct dfs_info3_param *refs, int numrefs,
struct dfs_cache_entry *ce, const char *tgthint)
{
int i;
ce->ce_ttl = refs[0].ttl;
ce->ce_etime = get_expire_time(ce->ce_ttl);
ce->ce_srvtype = refs[0].server_type;
ce->ce_flags = refs[0].ref_flag;
ce->ce_path_consumed = refs[0].path_consumed;
for (i = 0; i < numrefs; i++) {
struct dfs_cache_tgt *t;
t = alloc_tgt(refs[i].node_name);
if (IS_ERR(t)) {
free_tgts(ce);
return PTR_ERR(t);
}
if (tgthint && !strcasecmp(t->t_name, tgthint)) {
list_add(&t->t_list, &ce->ce_tlist);
tgthint = NULL;
} else {
list_add_tail(&t->t_list, &ce->ce_tlist);
}
ce->ce_numtgts++;
}
ce->ce_tgthint = list_first_entry_or_null(&ce->ce_tlist,
struct dfs_cache_tgt, t_list);
return 0;
}
/* Allocate a new cache entry */
static struct dfs_cache_entry *
alloc_cache_entry(const char *path, const struct dfs_info3_param *refs,
int numrefs)
{
struct dfs_cache_entry *ce;
int rc;
ce = kmem_cache_zalloc(dfs_cache_slab, GFP_KERNEL);
if (!ce)
return ERR_PTR(-ENOMEM);
ce->ce_path = kstrdup_const(path, GFP_KERNEL);
if (!ce->ce_path) {
kfree(ce);
return ERR_PTR(-ENOMEM);
}
INIT_HLIST_NODE(&ce->ce_hlist);
INIT_LIST_HEAD(&ce->ce_tlist);
rc = copy_ref_data(refs, numrefs, ce, NULL);
if (rc) {
kfree(ce->ce_path);
kfree(ce);
ce = ERR_PTR(rc);
}
return ce;
}
static void remove_oldest_entry(void)
{
int bucket;
struct dfs_cache_entry *ce;
struct dfs_cache_entry *to_del = NULL;
rcu_read_lock();
hash_for_each_rcu(dfs_cache_htable, bucket, ce, ce_hlist) {
if (!to_del || timespec64_compare(&ce->ce_etime,
&to_del->ce_etime) < 0)
to_del = ce;
}
if (!to_del) {
cifs_dbg(FYI, "%s: no entry to remove", __func__);
goto out;
}
cifs_dbg(FYI, "%s: removing entry", __func__);
dump_ce(to_del);
flush_cache_ent(to_del);
out:
rcu_read_unlock();
}
/* Add a new DFS cache entry */
static inline struct dfs_cache_entry *
add_cache_entry(unsigned int hash, const char *path,
const struct dfs_info3_param *refs, int numrefs)
{
struct dfs_cache_entry *ce;
ce = alloc_cache_entry(path, refs, numrefs);
if (IS_ERR(ce))
return ce;
hlist_add_head_rcu(&ce->ce_hlist, &dfs_cache_htable[hash]);
mutex_lock(&dfs_cache.dc_lock);
if (dfs_cache.dc_ttl < 0) {
dfs_cache.dc_ttl = ce->ce_ttl;
queue_delayed_work(cifsiod_wq, &dfs_cache.dc_refresh,
dfs_cache.dc_ttl * HZ);
} else {
dfs_cache.dc_ttl = min_t(int, dfs_cache.dc_ttl, ce->ce_ttl);
mod_delayed_work(cifsiod_wq, &dfs_cache.dc_refresh,
dfs_cache.dc_ttl * HZ);
}
mutex_unlock(&dfs_cache.dc_lock);
return ce;
}
static struct dfs_cache_entry *__find_cache_entry(unsigned int hash,
const char *path)
{
struct dfs_cache_entry *ce;
bool found = false;
rcu_read_lock();
hlist_for_each_entry_rcu(ce, &dfs_cache_htable[hash], ce_hlist) {
if (!strcasecmp(path, ce->ce_path)) {
#ifdef CONFIG_CIFS_DEBUG2
char *name = get_tgt_name(ce);
if (unlikely(IS_ERR(name))) {
rcu_read_unlock();
return ERR_CAST(name);
}
cifs_dbg(FYI, "%s: cache hit\n", __func__);
cifs_dbg(FYI, "%s: target hint: %s\n", __func__, name);
#endif
found = true;
break;
}
}
rcu_read_unlock();
return found ? ce : ERR_PTR(-ENOENT);
}
/*
* Find a DFS cache entry in hash table and optionally check prefix path against
* @path.
* Use whole path components in the match.
* Return ERR_PTR(-ENOENT) if the entry is not found.
*/
static inline struct dfs_cache_entry *find_cache_entry(const char *path,
unsigned int *hash)
{
*hash = cache_entry_hash(path, strlen(path));
return __find_cache_entry(*hash, path);
}
static inline void destroy_slab_cache(void)
{
rcu_barrier();
kmem_cache_destroy(dfs_cache_slab);
}
static inline void free_vol(struct dfs_cache_vol_info *vi)
{
list_del(&vi->vi_list);
kfree(vi->vi_fullpath);
cifs_cleanup_volume_info_contents(&vi->vi_vol);
kfree(vi);
}
static inline void free_vol_list(void)
{
struct dfs_cache_vol_info *vi, *nvi;
list_for_each_entry_safe(vi, nvi, &dfs_cache.dc_vol_list, vi_list)
free_vol(vi);
}
/**
* dfs_cache_destroy - destroy DFS referral cache
*/
void dfs_cache_destroy(void)
{
cancel_delayed_work_sync(&dfs_cache.dc_refresh);
unload_nls(dfs_cache.dc_nlsc);
free_vol_list();
mutex_destroy(&dfs_cache.dc_lock);
flush_cache_ents();
destroy_slab_cache();
mutex_destroy(&dfs_cache_list_lock);
cifs_dbg(FYI, "%s: destroyed DFS referral cache\n", __func__);
}
static inline struct dfs_cache_entry *
__update_cache_entry(const char *path, const struct dfs_info3_param *refs,
int numrefs)
{
int rc;
unsigned int h;
struct dfs_cache_entry *ce;
char *s, *th = NULL;
ce = find_cache_entry(path, &h);
if (IS_ERR(ce))
return ce;
if (ce->ce_tgthint) {
s = ce->ce_tgthint->t_name;
th = kstrndup(s, strlen(s), GFP_KERNEL);
if (!th)
return ERR_PTR(-ENOMEM);
}
free_tgts(ce);
ce->ce_numtgts = 0;
rc = copy_ref_data(refs, numrefs, ce, th);
kfree(th);
if (rc)
ce = ERR_PTR(rc);
return ce;
}
/* Update an expired cache entry by getting a new DFS referral from server */
static struct dfs_cache_entry *
update_cache_entry(const unsigned int xid, struct cifs_ses *ses,
const struct nls_table *nls_codepage, int remap,
const char *path, struct dfs_cache_entry *ce)
{
int rc;
struct dfs_info3_param *refs = NULL;
int numrefs = 0;
cifs_dbg(FYI, "%s: update expired cache entry\n", __func__);
/*
* Check if caller provided enough parameters to update an expired
* entry.
*/
if (!ses || !ses->server || !ses->server->ops->get_dfs_refer)
return ERR_PTR(-ETIME);
if (unlikely(!nls_codepage))
return ERR_PTR(-ETIME);
cifs_dbg(FYI, "%s: DFS referral request for %s\n", __func__, path);
rc = ses->server->ops->get_dfs_refer(xid, ses, path, &refs, &numrefs,
nls_codepage, remap);
if (rc)
ce = ERR_PTR(rc);
else
ce = __update_cache_entry(path, refs, numrefs);
dump_refs(refs, numrefs);
free_dfs_info_array(refs, numrefs);
return ce;
}
/*
* 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_dfs_mount() and expand_dfs_referral() are supposed to
* handle them properly.
*/
static struct dfs_cache_entry *
do_dfs_cache_find(const unsigned int xid, struct cifs_ses *ses,
const struct nls_table *nls_codepage, int remap,
const char *path, bool noreq)
{
int rc;
unsigned int h;
struct dfs_cache_entry *ce;
struct dfs_info3_param *nrefs;
int numnrefs;
cifs_dbg(FYI, "%s: search path: %s\n", __func__, path);
ce = find_cache_entry(path, &h);
if (IS_ERR(ce)) {
cifs_dbg(FYI, "%s: cache miss\n", __func__);
/*
* If @noreq is set, no requests will be sent to the server for
* either updating or getting a new DFS referral.
*/
if (noreq)
return ce;
/*
* No cache entry was found, so check for valid parameters that
* will be required to get a new DFS referral and then create a
* new cache entry.
*/
if (!ses || !ses->server || !ses->server->ops->get_dfs_refer) {
ce = ERR_PTR(-EOPNOTSUPP);
return ce;
}
if (unlikely(!nls_codepage)) {
ce = ERR_PTR(-EINVAL);
return ce;
}
nrefs = NULL;
numnrefs = 0;
cifs_dbg(FYI, "%s: DFS referral request for %s\n", __func__,
path);
rc = ses->server->ops->get_dfs_refer(xid, ses, path, &nrefs,
&numnrefs, nls_codepage,
remap);
if (rc) {
ce = ERR_PTR(rc);
return ce;
}
dump_refs(nrefs, numnrefs);
cifs_dbg(FYI, "%s: new cache entry\n", __func__);
if (dfs_cache_count >= DFS_CACHE_MAX_ENTRIES) {
cifs_dbg(FYI, "%s: reached max cache size (%d)",
__func__, DFS_CACHE_MAX_ENTRIES);
remove_oldest_entry();
}
ce = add_cache_entry(h, path, nrefs, numnrefs);
free_dfs_info_array(nrefs, numnrefs);
if (IS_ERR(ce))
return ce;
dfs_cache_count++;
}
dump_ce(ce);
/* Just return the found cache entry in case @noreq is set */
if (noreq)
return ce;
if (cache_entry_expired(ce)) {
cifs_dbg(FYI, "%s: expired cache entry\n", __func__);
ce = update_cache_entry(xid, ses, nls_codepage, remap, path,
ce);
if (IS_ERR(ce)) {
cifs_dbg(FYI, "%s: failed to update expired entry\n",
__func__);
}
}
return ce;
}
/* Set up a new DFS referral from a given cache entry */
static int setup_ref(const char *path, const struct dfs_cache_entry *ce,
struct dfs_info3_param *ref, const char *tgt)
{
int rc;
cifs_dbg(FYI, "%s: set up new ref\n", __func__);
memset(ref, 0, sizeof(*ref));
ref->path_name = kstrndup(path, strlen(path), GFP_KERNEL);
if (!ref->path_name)
return -ENOMEM;
ref->path_consumed = ce->ce_path_consumed;
ref->node_name = kstrndup(tgt, strlen(tgt), GFP_KERNEL);
if (!ref->node_name) {
rc = -ENOMEM;
goto err_free_path;
}
ref->ttl = ce->ce_ttl;
ref->server_type = ce->ce_srvtype;
ref->ref_flag = ce->ce_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_tgt_list(const struct dfs_cache_entry *ce,
struct dfs_cache_tgt_list *tl)
{
int rc;
struct list_head *head = &tl->tl_list;
struct dfs_cache_tgt *t;
struct dfs_cache_tgt_iterator *it, *nit;
memset(tl, 0, sizeof(*tl));
INIT_LIST_HEAD(head);
list_for_each_entry(t, &ce->ce_tlist, t_list) {
it = kzalloc(sizeof(*it), GFP_KERNEL);
if (!it) {
rc = -ENOMEM;
goto err_free_it;
}
it->it_name = kstrndup(t->t_name, strlen(t->t_name),
GFP_KERNEL);
if (!it->it_name) {
rc = -ENOMEM;
goto err_free_it;
}
if (ce->ce_tgthint == t)
list_add(&it->it_list, head);
else
list_add_tail(&it->it_list, head);
}
tl->tl_numtgts = ce->ce_numtgts;
return 0;
err_free_it:
list_for_each_entry_safe(it, nit, head, 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
* @nls_codepage: charset conversion
* @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 *nls_codepage, int remap,
const char *path, struct dfs_info3_param *ref,
struct dfs_cache_tgt_list *tgt_list)
{
int rc;
char *npath;
struct dfs_cache_entry *ce;
if (unlikely(!is_path_valid(path)))
return -EINVAL;
rc = get_normalized_path(path, &npath);
if (rc)
return rc;
mutex_lock(&dfs_cache_list_lock);
ce = do_dfs_cache_find(xid, ses, nls_codepage, remap, npath, false);
if (!IS_ERR(ce)) {
if (ref)
rc = setup_ref(path, ce, ref, get_tgt_name(ce));
else
rc = 0;
if (!rc && tgt_list)
rc = get_tgt_list(ce, tgt_list);
} else {
rc = PTR_ERR(ce);
}
mutex_unlock(&dfs_cache_list_lock);
free_normalized_path(path, 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: 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;
char *npath;
struct dfs_cache_entry *ce;
if (unlikely(!is_path_valid(path)))
return -EINVAL;
rc = get_normalized_path(path, &npath);
if (rc)
return rc;
mutex_lock(&dfs_cache_list_lock);
ce = do_dfs_cache_find(0, NULL, NULL, 0, npath, true);
if (IS_ERR(ce)) {
rc = PTR_ERR(ce);
goto out;
}
if (ref)
rc = setup_ref(path, ce, ref, get_tgt_name(ce));
else
rc = 0;
if (!rc && tgt_list)
rc = get_tgt_list(ce, tgt_list);
out:
mutex_unlock(&dfs_cache_list_lock);
free_normalized_path(path, npath);
return rc;
}
/**
* dfs_cache_update_tgthint - update target hint of 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.
*
* @xid: syscall id
* @ses: smb session
* @nls_codepage: charset conversion
* @remap: type of character remapping for paths
* @path: path to lookup in DFS referral cache.
* @it: DFS target iterator
*
* Return zero if the target hint was updated successfully, otherwise non-zero.
*/
int dfs_cache_update_tgthint(const unsigned int xid, struct cifs_ses *ses,
const struct nls_table *nls_codepage, int remap,
const char *path,
const struct dfs_cache_tgt_iterator *it)
{
int rc;
char *npath;
struct dfs_cache_entry *ce;
struct dfs_cache_tgt *t;
if (unlikely(!is_path_valid(path)))
return -EINVAL;
rc = get_normalized_path(path, &npath);
if (rc)
return rc;
cifs_dbg(FYI, "%s: path: %s\n", __func__, npath);
mutex_lock(&dfs_cache_list_lock);
ce = do_dfs_cache_find(xid, ses, nls_codepage, remap, npath, false);
if (IS_ERR(ce)) {
rc = PTR_ERR(ce);
goto out;
}
rc = 0;
t = ce->ce_tgthint;
if (likely(!strcasecmp(it->it_name, t->t_name)))
goto out;
list_for_each_entry(t, &ce->ce_tlist, t_list) {
if (!strcasecmp(t->t_name, it->it_name)) {
ce->ce_tgthint = t;
cifs_dbg(FYI, "%s: new target hint: %s\n", __func__,
it->it_name);
break;
}
}
out:
mutex_unlock(&dfs_cache_list_lock);
free_normalized_path(path, npath);
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: 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.
*/
int dfs_cache_noreq_update_tgthint(const char *path,
const struct dfs_cache_tgt_iterator *it)
{
int rc;
char *npath;
struct dfs_cache_entry *ce;
struct dfs_cache_tgt *t;
if (unlikely(!is_path_valid(path)) || !it)
return -EINVAL;
rc = get_normalized_path(path, &npath);
if (rc)
return rc;
cifs_dbg(FYI, "%s: path: %s\n", __func__, npath);
mutex_lock(&dfs_cache_list_lock);
ce = do_dfs_cache_find(0, NULL, NULL, 0, npath, true);
if (IS_ERR(ce)) {
rc = PTR_ERR(ce);
goto out;
}
rc = 0;
t = ce->ce_tgthint;
if (unlikely(!strcasecmp(it->it_name, t->t_name)))
goto out;
list_for_each_entry(t, &ce->ce_tlist, t_list) {
if (!strcasecmp(t->t_name, it->it_name)) {
ce->ce_tgthint = t;
cifs_dbg(FYI, "%s: new target hint: %s\n", __func__,
it->it_name);
break;
}
}
out:
mutex_unlock(&dfs_cache_list_lock);
free_normalized_path(path, npath);
return rc;
}
/**
* dfs_cache_get_tgt_referral - returns a DFS referral (@ref) from a given
* target iterator (@it).
*
* @path: 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;
char *npath;
struct dfs_cache_entry *ce;
unsigned int h;
if (!it || !ref)
return -EINVAL;
if (unlikely(!is_path_valid(path)))
return -EINVAL;
rc = get_normalized_path(path, &npath);
if (rc)
return rc;
cifs_dbg(FYI, "%s: path: %s\n", __func__, npath);
mutex_lock(&dfs_cache_list_lock);
ce = find_cache_entry(npath, &h);
if (IS_ERR(ce)) {
rc = PTR_ERR(ce);
goto out;
}
cifs_dbg(FYI, "%s: target name: %s\n", __func__, it->it_name);
rc = setup_ref(path, ce, ref, it->it_name);
out:
mutex_unlock(&dfs_cache_list_lock);
free_normalized_path(path, npath);
return rc;
}
static int dup_vol(struct smb_vol *vol, struct smb_vol *new)
{
memcpy(new, vol, sizeof(*new));
if (vol->username) {
new->username = kstrndup(vol->username, strlen(vol->username),
GFP_KERNEL);
if (!new->username)
return -ENOMEM;
}
if (vol->password) {
new->password = kstrndup(vol->password, strlen(vol->password),
GFP_KERNEL);
if (!new->password)
goto err_free_username;
}
if (vol->UNC) {
cifs_dbg(FYI, "%s: vol->UNC: %s\n", __func__, vol->UNC);
new->UNC = kstrndup(vol->UNC, strlen(vol->UNC), GFP_KERNEL);
if (!new->UNC)
goto err_free_password;
}
if (vol->domainname) {
new->domainname = kstrndup(vol->domainname,
strlen(vol->domainname), GFP_KERNEL);
if (!new->domainname)
goto err_free_unc;
}
if (vol->iocharset) {
new->iocharset = kstrndup(vol->iocharset,
strlen(vol->iocharset), GFP_KERNEL);
if (!new->iocharset)
goto err_free_domainname;
}
if (vol->prepath) {
cifs_dbg(FYI, "%s: vol->prepath: %s\n", __func__, vol->prepath);
new->prepath = kstrndup(vol->prepath, strlen(vol->prepath),
GFP_KERNEL);
if (!new->prepath)
goto err_free_iocharset;
}
return 0;
err_free_iocharset:
kfree(new->iocharset);
err_free_domainname:
kfree(new->domainname);
err_free_unc:
kfree(new->UNC);
err_free_password:
kfree(new->password);
err_free_username:
kfree(new->username);
kfree(new);
return -ENOMEM;
}
/**
* dfs_cache_add_vol - add a cifs volume during mount() that will be handled by
* DFS cache refresh worker.
*
* @vol: cifs volume.
* @fullpath: origin full path.
*
* Return zero if volume was set up correctly, otherwise non-zero.
*/
int dfs_cache_add_vol(struct smb_vol *vol, const char *fullpath)
{
int rc;
struct dfs_cache_vol_info *vi;
if (!vol || !fullpath)
return -EINVAL;
cifs_dbg(FYI, "%s: fullpath: %s\n", __func__, fullpath);
vi = kzalloc(sizeof(*vi), GFP_KERNEL);
if (!vi)
return -ENOMEM;
vi->vi_fullpath = kstrndup(fullpath, strlen(fullpath), GFP_KERNEL);
if (!vi->vi_fullpath) {
rc = -ENOMEM;
goto err_free_vi;
}
rc = dup_vol(vol, &vi->vi_vol);
if (rc)
goto err_free_fullpath;
mutex_lock(&dfs_cache.dc_lock);
list_add_tail(&vi->vi_list, &dfs_cache.dc_vol_list);
mutex_unlock(&dfs_cache.dc_lock);
return 0;
err_free_fullpath:
kfree(vi->vi_fullpath);
err_free_vi:
kfree(vi);
return rc;
}
static inline struct dfs_cache_vol_info *find_vol(const char *fullpath)
{
struct dfs_cache_vol_info *vi;
list_for_each_entry(vi, &dfs_cache.dc_vol_list, vi_list) {
cifs_dbg(FYI, "%s: vi->vi_fullpath: %s\n", __func__,
vi->vi_fullpath);
if (!strcasecmp(vi->vi_fullpath, fullpath))
return vi;
}
return ERR_PTR(-ENOENT);
}
/**
* dfs_cache_update_vol - update vol info in DFS cache after failover
*
* @fullpath: fullpath to look up in volume list.
* @server: TCP ses pointer.
*
* Return zero if volume was updated, otherwise non-zero.
*/
int dfs_cache_update_vol(const char *fullpath, struct TCP_Server_Info *server)
{
int rc;
struct dfs_cache_vol_info *vi;
if (!fullpath || !server)
return -EINVAL;
cifs_dbg(FYI, "%s: fullpath: %s\n", __func__, fullpath);
mutex_lock(&dfs_cache.dc_lock);
vi = find_vol(fullpath);
if (IS_ERR(vi)) {
rc = PTR_ERR(vi);
goto out;
}
cifs_dbg(FYI, "%s: updating volume info\n", __func__);
memcpy(&vi->vi_vol.dstaddr, &server->dstaddr,
sizeof(vi->vi_vol.dstaddr));
rc = 0;
out:
mutex_unlock(&dfs_cache.dc_lock);
return rc;
}
/**
* dfs_cache_del_vol - remove volume info in DFS cache during umount()
*
* @fullpath: fullpath to look up in volume list.
*/
void dfs_cache_del_vol(const char *fullpath)
{
struct dfs_cache_vol_info *vi;
if (!fullpath || !*fullpath)
return;
cifs_dbg(FYI, "%s: fullpath: %s\n", __func__, fullpath);
mutex_lock(&dfs_cache.dc_lock);
vi = find_vol(fullpath);
if (!IS_ERR(vi))
free_vol(vi);
mutex_unlock(&dfs_cache.dc_lock);
}
/* Get all tcons that are within a DFS namespace and can be refreshed */
static void get_tcons(struct TCP_Server_Info *server, struct list_head *head)
{
struct cifs_ses *ses;
struct cifs_tcon *tcon;
INIT_LIST_HEAD(head);
spin_lock(&cifs_tcp_ses_lock);
list_for_each_entry(ses, &server->smb_ses_list, smb_ses_list) {
list_for_each_entry(tcon, &ses->tcon_list, tcon_list) {
if (!tcon->need_reconnect && !tcon->need_reopen_files &&
tcon->dfs_path) {
tcon->tc_count++;
list_add_tail(&tcon->ulist, head);
}
}
if (ses->tcon_ipc && !ses->tcon_ipc->need_reconnect &&
ses->tcon_ipc->dfs_path) {
list_add_tail(&ses->tcon_ipc->ulist, head);
}
}
spin_unlock(&cifs_tcp_ses_lock);
}
/* Refresh DFS cache entry from a given tcon */
static void do_refresh_tcon(struct dfs_cache *dc, struct cifs_tcon *tcon)
{
int rc = 0;
unsigned int xid;
char *path, *npath;
unsigned int h;
struct dfs_cache_entry *ce;
struct dfs_info3_param *refs = NULL;
int numrefs = 0;
xid = get_xid();
path = tcon->dfs_path + 1;
rc = get_normalized_path(path, &npath);
if (rc)
goto out;
mutex_lock(&dfs_cache_list_lock);
ce = find_cache_entry(npath, &h);
mutex_unlock(&dfs_cache_list_lock);
if (IS_ERR(ce)) {
rc = PTR_ERR(ce);
goto out;
}
if (!cache_entry_expired(ce))
goto out;
if (unlikely(!tcon->ses->server->ops->get_dfs_refer)) {
rc = -EOPNOTSUPP;
} else {
rc = tcon->ses->server->ops->get_dfs_refer(xid, tcon->ses, path,
&refs, &numrefs,
dc->dc_nlsc,
tcon->remap);
if (!rc) {
mutex_lock(&dfs_cache_list_lock);
ce = __update_cache_entry(npath, refs, numrefs);
mutex_unlock(&dfs_cache_list_lock);
dump_refs(refs, numrefs);
free_dfs_info_array(refs, numrefs);
if (IS_ERR(ce))
rc = PTR_ERR(ce);
}
}
if (rc)
cifs_dbg(FYI, "%s: failed to update expired entry\n", __func__);
out:
free_xid(xid);
free_normalized_path(path, npath);
}
/*
* Worker that will refresh DFS cache based on lowest TTL value from a DFS
* referral.
*
* FIXME: ensure that all requests are sent to DFS root for refreshing the
* cache.
*/
static void refresh_cache_worker(struct work_struct *work)
{
struct dfs_cache *dc = container_of(work, struct dfs_cache,
dc_refresh.work);
struct dfs_cache_vol_info *vi;
struct TCP_Server_Info *server;
LIST_HEAD(list);
struct cifs_tcon *tcon, *ntcon;
mutex_lock(&dc->dc_lock);
list_for_each_entry(vi, &dc->dc_vol_list, vi_list) {
server = cifs_find_tcp_session(&vi->vi_vol);
if (IS_ERR_OR_NULL(server))
continue;
if (server->tcpStatus != CifsGood)
goto next;
get_tcons(server, &list);
list_for_each_entry_safe(tcon, ntcon, &list, ulist) {
do_refresh_tcon(dc, tcon);
list_del_init(&tcon->ulist);
cifs_put_tcon(tcon);
}
next:
cifs_put_tcp_session(server, 0);
}
queue_delayed_work(cifsiod_wq, &dc->dc_refresh, dc->dc_ttl * HZ);
mutex_unlock(&dc->dc_lock);
}
/* SPDX-License-Identifier: GPL-2.0 */
/*
* DFS referral cache routines
*
* Copyright (c) 2018 Paulo Alcantara <palcantara@suse.de>
*/
#ifndef _CIFS_DFS_CACHE_H
#define _CIFS_DFS_CACHE_H
#include <linux/nls.h>
#include <linux/list.h>
#include "cifsglob.h"
struct dfs_cache_tgt_list {
int tl_numtgts;
struct list_head tl_list;
};
struct dfs_cache_tgt_iterator {
char *it_name;
struct list_head it_list;
};
extern int dfs_cache_init(void);
extern void dfs_cache_destroy(void);
extern const struct file_operations dfscache_proc_fops;
extern int dfs_cache_find(const unsigned int xid, struct cifs_ses *ses,
const struct nls_table *nls_codepage, int remap,
const char *path, struct dfs_info3_param *ref,
struct dfs_cache_tgt_list *tgt_list);
extern int dfs_cache_noreq_find(const char *path, struct dfs_info3_param *ref,
struct dfs_cache_tgt_list *tgt_list);
extern int dfs_cache_update_tgthint(const unsigned int xid,
struct cifs_ses *ses,
const struct nls_table *nls_codepage,
int remap, const char *path,
const struct dfs_cache_tgt_iterator *it);
extern int
dfs_cache_noreq_update_tgthint(const char *path,
const struct dfs_cache_tgt_iterator *it);
extern int dfs_cache_get_tgt_referral(const char *path,
const struct dfs_cache_tgt_iterator *it,
struct dfs_info3_param *ref);
extern int dfs_cache_add_vol(struct smb_vol *vol, const char *fullpath);
extern int dfs_cache_update_vol(const char *fullpath,
struct TCP_Server_Info *server);
extern void dfs_cache_del_vol(const char *fullpath);
static inline struct dfs_cache_tgt_iterator *
dfs_cache_get_next_tgt(struct dfs_cache_tgt_list *tl,
struct dfs_cache_tgt_iterator *it)
{
if (!tl || list_empty(&tl->tl_list) || !it ||
list_is_last(&it->it_list, &tl->tl_list))
return NULL;
return list_next_entry(it, it_list);
}
static inline struct dfs_cache_tgt_iterator *
dfs_cache_get_tgt_iterator(struct dfs_cache_tgt_list *tl)
{
if (!tl)
return NULL;
return list_first_entry_or_null(&tl->tl_list,
struct dfs_cache_tgt_iterator,
it_list);
}
static inline void dfs_cache_free_tgts(struct dfs_cache_tgt_list *tl)
{
struct dfs_cache_tgt_iterator *it, *nit;
if (!tl || list_empty(&tl->tl_list))
return;
list_for_each_entry_safe(it, nit, &tl->tl_list, it_list) {
list_del(&it->it_list);
kfree(it->it_name);
kfree(it);
}
tl->tl_numtgts = 0;
}
static inline const char *
dfs_cache_get_tgt_name(const struct dfs_cache_tgt_iterator *it)
{
return it ? it->it_name : NULL;
}
static inline int
dfs_cache_get_nr_tgts(const struct dfs_cache_tgt_list *tl)
{
return tl ? tl->tl_numtgts : 0;
}
#endif /* _CIFS_DFS_CACHE_H */
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment