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SMB3: parsing for new snapshot timestamp mount parm

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New mount option "snapshot=<time>" to allow mounting an earlier
version of the remote volume (if such a snapshot exists on
the server).

Note that eventually specifying a snapshot time of 1 will allow
the user to mount the oldest snapshot. A subsequent patch
add the processing for that and another for actually specifying
the "time warp" create context on SMB2/SMB3 open.

Check to make sure SMB2 negotiated, and ensure that
we use a different tcon if mount same share twice
but with different snaphshot times

Signed-off-by: Steve French <smfrench@gmail.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
This commit is contained in:
Steve French 2016-11-11 22:36:20 -06:00
parent 43c4f67c96
commit 8b217fe7fc
2 changed files with 37 additions and 3 deletions
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2
fs/cifs/cifsglob.h
View File

@ -525,6 +525,7 @@ struct smb_vol {
struct sockaddr_storage srcaddr; /* allow binding to a local IP */
struct nls_table *local_nls;
unsigned int echo_interval; /* echo interval in secs */
__u64 snapshot_time; /* needed for timewarp tokens */
unsigned int max_credits; /* smb3 max_credits 10 < credits < 60000 */
};
@ -932,6 +933,7 @@ struct cifs_tcon {
__u32 maximal_access;
__u32 vol_serial_number;
__le64 vol_create_time;
__u64 snapshot_time; /* for timewarp tokens - timestamp of snapshot */
__u32 ss_flags; /* sector size flags */
__u32 perf_sector_size; /* best sector size for perf */
__u32 max_chunks;

38
fs/cifs/connect.c
View File

@ -95,6 +95,7 @@ enum {
Opt_dirmode, Opt_port,
Opt_rsize, Opt_wsize, Opt_actimeo,
Opt_echo_interval, Opt_max_credits,
Opt_snapshot,
/* Mount options which take string value */
Opt_user, Opt_pass, Opt_ip,
@ -191,6 +192,7 @@ static const match_table_t cifs_mount_option_tokens = {
{ Opt_actimeo, "actimeo=%s" },
{ Opt_echo_interval, "echo_interval=%s" },
{ Opt_max_credits, "max_credits=%s" },
{ Opt_snapshot, "snapshot=%s" },
{ Opt_blank_user, "user=" },
{ Opt_blank_user, "username=" },
@ -1601,6 +1603,14 @@ cifs_parse_mount_options(const char *mountdata, const char *devname,
}
vol->echo_interval = option;
break;
case Opt_snapshot:
if (get_option_ul(args, &option)) {
cifs_dbg(VFS, "%s: Invalid snapshot time\n",
__func__);
goto cifs_parse_mount_err;
}
vol->snapshot_time = option;
break;
case Opt_max_credits:
if (get_option_ul(args, &option) || (option < 20) ||
(option > 60000)) {
@ -2586,7 +2596,7 @@ static int match_tcon(struct cifs_tcon *tcon, const char *unc)
}
static struct cifs_tcon *
cifs_find_tcon(struct cifs_ses *ses, const char *unc)
cifs_find_tcon(struct cifs_ses *ses, struct smb_vol *volume_info)
{
struct list_head *tmp;
struct cifs_tcon *tcon;
@ -2594,8 +2604,14 @@ cifs_find_tcon(struct cifs_ses *ses, const char *unc)
spin_lock(&cifs_tcp_ses_lock);
list_for_each(tmp, &ses->tcon_list) {
tcon = list_entry(tmp, struct cifs_tcon, tcon_list);
if (!match_tcon(tcon, unc))
if (!match_tcon(tcon, volume_info->UNC))
continue;
#ifdef CONFIG_CIFS_SMB2
if (tcon->snapshot_time != volume_info->snapshot_time)
continue;
#endif /* CONFIG_CIFS_SMB2 */
++tcon->tc_count;
spin_unlock(&cifs_tcp_ses_lock);
return tcon;
@ -2636,7 +2652,7 @@ cifs_get_tcon(struct cifs_ses *ses, struct smb_vol *volume_info)
int rc, xid;
struct cifs_tcon *tcon;
tcon = cifs_find_tcon(ses, volume_info->UNC);
tcon = cifs_find_tcon(ses, volume_info);
if (tcon) {
cifs_dbg(FYI, "Found match on UNC path\n");
/* existing tcon already has a reference */
@ -2657,6 +2673,22 @@ cifs_get_tcon(struct cifs_ses *ses, struct smb_vol *volume_info)
goto out_fail;
}
if (volume_info->snapshot_time) {
#ifdef CONFIG_CIFS_SMB2
if (ses->server->vals->protocol_id == 0) {
cifs_dbg(VFS,
"Use SMB2 or later for snapshot mount option\n");
rc = -EOPNOTSUPP;
goto out_fail;
} else
tcon->snapshot_time = volume_info->snapshot_time;
#else
cifs_dbg(VFS, "Snapshot mount option requires SMB2 support\n");
rc = -EOPNOTSUPP;
goto out_fail;
#endif /* CONFIG_CIFS_SMB2 */
}
tcon->ses = ses;
if (volume_info->password) {
tcon->password = kstrdup(volume_info->password, GFP_KERNEL);