Skip to content

Commit

Permalink
cifs: Make use of DFS cache to get new DFS referrals
Browse files Browse the repository at this point in the history 
This patch will make use of DFS cache routines where appropriate and
do not always request a new referral from server.

Signed-off-by: Paulo Alcantara <palcantara@suse.de>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
  • Loading branch information
Paulo Alcantara authored and Steve French committed Dec 28, 2018
1 parent e8bcdfd commit 1c78022
Show file tree
Hide file tree
Showing 6 changed files with 113 additions and 84 deletions.
100 changes: 62 additions & 38 deletions fs/cifs/cifs_dfs_ref.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -25,6 +25,7 @@
#include "dns_resolve.h"
#include "cifs_debug.h"
#include "cifs_unicode.h"
#include "dfs_cache.h"

static LIST_HEAD(cifs_dfs_automount_list);

Expand Down Expand Up @@ -285,16 +286,16 @@ static void dump_referral(const struct dfs_info3_param *ref)
*/
static struct vfsmount *cifs_dfs_do_automount(struct dentry *mntpt)
{
struct dfs_info3_param *referrals = NULL;
unsigned int num_referrals = 0;
struct dfs_info3_param referral = {0};
struct cifs_sb_info *cifs_sb;
struct cifs_ses *ses;
char *full_path;
struct cifs_tcon *tcon;
char *full_path, *root_path;
unsigned int xid;
int i;
int len;
int rc;
struct vfsmount *mnt;
struct tcon_link *tlink;
char sep;

cifs_dbg(FYI, "in %s\n", __func__);
BUG_ON(IS_ROOT(mntpt));
Expand All @@ -313,53 +314,76 @@ static struct vfsmount *cifs_dfs_do_automount(struct dentry *mntpt)
goto cdda_exit;
}

sep = CIFS_DIR_SEP(cifs_sb);

/* always use tree name prefix */
full_path = build_path_from_dentry_optional_prefix(mntpt, true);
if (full_path == NULL)
goto cdda_exit;

tlink = cifs_sb_tlink(cifs_sb);
if (IS_ERR(tlink)) {
mnt = ERR_CAST(tlink);
cifs_dbg(FYI, "%s: full_path: %s\n", __func__, full_path);

if (!cifs_sb_master_tlink(cifs_sb)) {
cifs_dbg(FYI, "%s: master tlink is NULL\n", __func__);
goto free_full_path;
}

tcon = cifs_sb_master_tcon(cifs_sb);
if (!tcon) {
cifs_dbg(FYI, "%s: master tcon is NULL\n", __func__);
goto free_full_path;
}
ses = tlink_tcon(tlink)->ses;

root_path = kstrdup(tcon->treeName, GFP_KERNEL);
if (!root_path) {
mnt = ERR_PTR(-ENOMEM);
goto free_full_path;
}
cifs_dbg(FYI, "%s: root path: %s\n", __func__, root_path);

ses = tcon->ses;
xid = get_xid();
rc = get_dfs_path(xid, ses, full_path + 1, cifs_sb->local_nls,
&num_referrals, &referrals,
cifs_remap(cifs_sb));
free_xid(xid);

cifs_put_tlink(tlink);

mnt = ERR_PTR(-ENOENT);
for (i = 0; i < num_referrals; i++) {
int len;
dump_referral(referrals + i);
/* connect to a node */
len = strlen(referrals[i].node_name);
if (len < 2) {
cifs_dbg(VFS, "%s: Net Address path too short: %s\n",
__func__, referrals[i].node_name);
mnt = ERR_PTR(-EINVAL);
break;
}
mnt = cifs_dfs_do_refmount(mntpt, cifs_sb,
full_path, referrals + i);
cifs_dbg(FYI, "%s: cifs_dfs_do_refmount:%s , mnt:%p\n",
__func__, referrals[i].node_name, mnt);
if (!IS_ERR(mnt))
goto success;
/*
* If DFS root has been expired, then unconditionally fetch it again to
* refresh DFS referral cache.
*/
rc = dfs_cache_find(xid, ses, cifs_sb->local_nls, cifs_remap(cifs_sb),
root_path + 1, NULL, NULL);
if (!rc) {
rc = dfs_cache_find(xid, ses, cifs_sb->local_nls,
cifs_remap(cifs_sb), full_path + 1,
&referral, NULL);
}

/* no valid submounts were found; return error from get_dfs_path() by
* preference */
if (rc != 0)
free_xid(xid);

if (rc) {
mnt = ERR_PTR(rc);
goto free_root_path;
}

success:
free_dfs_info_array(referrals, num_referrals);
dump_referral(&referral);

len = strlen(referral.node_name);
if (len < 2) {
cifs_dbg(VFS, "%s: Net Address path too short: %s\n",
__func__, referral.node_name);
mnt = ERR_PTR(-EINVAL);
goto free_dfs_ref;
}
/*
* cifs_mount() will retry every available node server in case
* of failures.
*/
mnt = cifs_dfs_do_refmount(mntpt, cifs_sb, full_path, &referral);
cifs_dbg(FYI, "%s: cifs_dfs_do_refmount:%s , mnt:%p\n", __func__,
referral.node_name, mnt);

free_dfs_ref:
free_dfs_info_param(&referral);
free_root_path:
kfree(root_path);
free_full_path:
kfree(full_path);
cdda_exit:
Expand Down
17 changes: 16 additions & 1 deletion fs/cifs/cifsfs.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -52,6 +52,9 @@
#include "cifs_spnego.h"
#include "fscache.h"
#include "smb2pdu.h"
#ifdef CONFIG_CIFS_DFS_UPCALL
#include "dfs_cache.h"
#endif

int cifsFYI = 0;
bool traceSMB;
Expand Down Expand Up @@ -1494,10 +1497,15 @@ init_cifs(void)
if (rc)
goto out_destroy_mids;

#ifdef CONFIG_CIFS_DFS_UPCALL
rc = dfs_cache_init();
if (rc)
goto out_destroy_request_bufs;
#endif /* CONFIG_CIFS_DFS_UPCALL */
#ifdef CONFIG_CIFS_UPCALL
rc = init_cifs_spnego();
if (rc)
goto out_destroy_request_bufs;
goto out_destroy_dfs_cache;
#endif /* CONFIG_CIFS_UPCALL */

#ifdef CONFIG_CIFS_ACL
Expand Down Expand Up @@ -1525,6 +1533,10 @@ init_cifs(void)
#endif
#ifdef CONFIG_CIFS_UPCALL
exit_cifs_spnego();
out_destroy_dfs_cache:
#endif
#ifdef CONFIG_CIFS_DFS_UPCALL
dfs_cache_destroy();
out_destroy_request_bufs:
#endif
cifs_destroy_request_bufs();
Expand Down Expand Up @@ -1555,6 +1567,9 @@ exit_cifs(void)
#endif
#ifdef CONFIG_CIFS_UPCALL
exit_cifs_spnego();
#endif
#ifdef CONFIG_CIFS_DFS_UPCALL
dfs_cache_destroy();
#endif
cifs_destroy_request_bufs();
cifs_destroy_mids();
Expand Down
1 change: 0 additions & 1 deletion fs/cifs/cifsglob.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1551,7 +1551,6 @@ static inline void free_dfs_info_param(struct dfs_info3_param *param)
if (param) {
kfree(param->path_name);
kfree(param->node_name);
kfree(param);
}
}

Expand Down
19 changes: 14 additions & 5 deletions fs/cifs/cifsproto.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -22,6 +22,9 @@
#define _CIFSPROTO_H
#include <linux/nls.h>
#include "trace.h"
#ifdef CONFIG_CIFS_DFS_UPCALL
#include "dfs_cache.h"
#endif

struct statfs;
struct smb_vol;
Expand Down Expand Up @@ -294,11 +297,6 @@ extern int CIFSGetDFSRefer(const unsigned int xid, struct cifs_ses *ses,
unsigned int *num_of_nodes,
const struct nls_table *nls_codepage, int remap);

extern int get_dfs_path(const unsigned int xid, struct cifs_ses *ses,
const char *old_path,
const struct nls_table *nls_codepage,
unsigned int *num_referrals,
struct dfs_info3_param **referrals, int remap);
extern int parse_dfs_referrals(struct get_dfs_referral_rsp *rsp, u32 rsp_size,
unsigned int *num_of_nodes,
struct dfs_info3_param **target_nodes,
Expand Down Expand Up @@ -567,4 +565,15 @@ void cifs_free_hash(struct crypto_shash **shash, struct sdesc **sdesc);
extern void rqst_page_get_length(struct smb_rqst *rqst, unsigned int page,
unsigned int *len, unsigned int *offset);

#ifdef CONFIG_CIFS_DFS_UPCALL
static inline int get_dfs_path(const unsigned int xid, struct cifs_ses *ses,
const char *old_path,
const struct nls_table *nls_codepage,
struct dfs_info3_param *referral, int remap)
{
return dfs_cache_find(xid, ses, nls_codepage, remap, old_path,
referral, NULL);
}
#endif

#endif /* _CIFSPROTO_H */
45 changes: 14 additions & 31 deletions fs/cifs/connect.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -56,6 +56,10 @@
#include "fscache.h"
#include "smb2proto.h"
#include "smbdirect.h"
#include "dns_resolve.h"
#ifdef CONFIG_CIFS_DFS_UPCALL
#include "dfs_cache.h"
#endif

extern mempool_t *cifs_req_poolp;
extern bool disable_legacy_dialects;
Expand Down Expand Up @@ -3262,25 +3266,6 @@ cifs_match_super(struct super_block *sb, void *data)
return rc;
}

int
get_dfs_path(const unsigned int xid, struct cifs_ses *ses, const char *old_path,
const struct nls_table *nls_codepage, unsigned int *num_referrals,
struct dfs_info3_param **referrals, int remap)
{
int rc = 0;

if (!ses->server->ops->get_dfs_refer)
return -ENOSYS;

*num_referrals = 0;
*referrals = NULL;

rc = ses->server->ops->get_dfs_refer(xid, ses, old_path,
referrals, num_referrals,
nls_codepage, remap);
return rc;
}

#ifdef CONFIG_DEBUG_LOCK_ALLOC
static struct lock_class_key cifs_key[2];
static struct lock_class_key cifs_slock_key[2];
Expand Down Expand Up @@ -3931,8 +3916,9 @@ build_unc_path_to_root(const struct smb_vol *vol,
return full_path;
}

/*
* Perform a dfs referral query for a share and (optionally) prefix
/**
* expand_dfs_referral - Perform a dfs referral query and update the cifs_sb
*
*
* If a referral is found, cifs_sb->mountdata will be (re-)allocated
* to a string containing updated options for the submount. Otherwise it
Expand All @@ -3947,8 +3933,7 @@ expand_dfs_referral(const unsigned int xid, struct cifs_ses *ses,
int check_prefix)
{
int rc;
unsigned int num_referrals = 0;
struct dfs_info3_param *referrals = NULL;
struct dfs_info3_param referral = {0};
char *full_path = NULL, *ref_path = NULL, *mdata = NULL;

if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NO_DFS)
Expand All @@ -3961,25 +3946,23 @@ expand_dfs_referral(const unsigned int xid, struct cifs_ses *ses,
/* For DFS paths, skip the first '\' of the UNC */
ref_path = check_prefix ? full_path + 1 : volume_info->UNC + 1;

rc = get_dfs_path(xid, ses, ref_path, cifs_sb->local_nls,
&num_referrals, &referrals, cifs_remap(cifs_sb));

if (!rc && num_referrals > 0) {
rc = dfs_cache_find(xid, ses, cifs_sb->local_nls, cifs_remap(cifs_sb),
ref_path, &referral, NULL);
if (!rc) {
char *fake_devname = NULL;

mdata = cifs_compose_mount_options(cifs_sb->mountdata,
full_path + 1, referrals,
full_path + 1, &referral,
&fake_devname);

free_dfs_info_array(referrals, num_referrals);
free_dfs_info_param(&referral);

if (IS_ERR(mdata)) {
rc = PTR_ERR(mdata);
mdata = NULL;
} else {
cifs_cleanup_volume_info_contents(volume_info);
rc = cifs_setup_volume_info(volume_info, mdata,
fake_devname, false);
fake_devname, false);
}
kfree(fake_devname);
kfree(cifs_sb->mountdata);
Expand Down
15 changes: 7 additions & 8 deletions fs/cifs/smb1ops.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -929,19 +929,18 @@ cifs_unix_dfs_readlink(const unsigned int xid, struct cifs_tcon *tcon,
{
#ifdef CONFIG_CIFS_DFS_UPCALL
int rc;
unsigned int num_referrals = 0;
struct dfs_info3_param *referrals = NULL;
struct dfs_info3_param referral = {0};

rc = get_dfs_path(xid, tcon->ses, searchName, nls_codepage,
&num_referrals, &referrals, 0);
rc = get_dfs_path(xid, tcon->ses, searchName, nls_codepage, &referral,
0);

if (!rc && num_referrals > 0) {
*symlinkinfo = kstrndup(referrals->node_name,
strlen(referrals->node_name),
if (!rc) {
*symlinkinfo = kstrndup(referral.node_name,
strlen(referral.node_name),
GFP_KERNEL);
free_dfs_info_param(&referral);
if (!*symlinkinfo)
rc = -ENOMEM;
free_dfs_info_array(referrals, num_referrals);
}
return rc;
#else /* No DFS support */
Expand Down

0 comments on commit 1c78022

Please sign in to comment.