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cifs: skip trailing separators of prefix paths 

During DFS failover, prefix paths may change, so make sure to not
leave trailing separators when parsing thew in
dfs_cache_get_tgt_share().  The separators of prefix paths are already
handled by build_path_from_dentry_optional_prefix().

Consider the following DFS link:

  //dom/dfs/link: [\srv1\share\dir1, \srv2\share\dir1]

Before commit:

  mount.cifs //dom/dfs/link
  tree connect to \\srv1\share; prefix_path=dir1
  disconnect srv1; failover to srv2
  tree connect to \\srv2\share; prefix_path=dir1\
  mv foo bar

  ...
  SMB2 430 Create Request File: dir1\\foo;GetInfo Request FILE_INFO/SMB2_FILE_ALL_INFO;Close Request
  SMB2 582 Create Response File: dir1\\foo;GetInfo Response;Close Response
  SMB2 430 Create Request File: dir1\\bar;GetInfo Request FILE_INFO/SMB2_FILE_ALL_INFO;Close Request
  SMB2 286 Create Response, Error: STATUS_OBJECT_NAME_NOT_FOUND;GetInfo Response, Error: STATUS_OBJECT_NAME_NOT_FOUND;Close Response, Error: STATUS_OBJECT_NAME_NOT_FOUND
  SMB2 462 Create Request File: dir1\\foo;SetInfo Request FILE_INFO/SMB2_FILE_RENAME_INFO NewName:dir1\\bar;Close Request
  SMB2 478 Create Response File: dir1\\foo;SetInfo Response, Error: STATUS_OBJECT_NAME_INVALID;Close Response

After commit:

  mount.cifs //dom/dfs/link
  tree connect to \\srv1\share; prefix_path=dir1
  disconnect srv1; failover to srv2
  tree connect to \\srv2\share; prefix_path=dir1
  mv foo bar

  ...
  SMB2 430 Create Request File: dir1\foo;GetInfo Request FILE_INFO/SMB2_FILE_ALL_INFO;Close Request
  SMB2 582 Create Response File: dir1\foo;GetInfo Response;Close Response
  SMB2 430 Create Request File: dir1\bar;GetInfo Request FILE_INFO/SMB2_FILE_ALL_INFO;Close Request
  SMB2 286 Create Response, Error: STATUS_OBJECT_NAME_NOT_FOUND;GetInfo Response, Error: STATUS_OBJECT_NAME_NOT_FOUND;Close Response, Error: STATUS_OBJECT_NAME_NOT_FOUND
  SMB2 462 Create Request File: dir1\foo;SetInfo Request FILE_INFO/SMB2_FILE_RENAME_INFO NewName:dir1\bar;Close Request
  SMB2 478 Create Response File: dir1\foo;SetInfo Response;Close Response

Signed-off-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Signed-off-by: Steve French <stfrench@microsoft.com>
This commit is contained in:
Paulo Alcantara 2022-06-03 16:13:02 -03:00 committed by Steve French
parent 096c956b0d
commit ef605e8682
1 changed files with 49 additions and 36 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

85
fs/cifs/dfs_cache.c
View File

@ -1229,6 +1229,30 @@ void dfs_cache_put_refsrv_sessions(const uuid_t *mount_id)
kref_put(&mg->refcount, mount_group_release);
}
/* 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
*
@ -1242,56 +1266,45 @@ void dfs_cache_put_refsrv_sessions(const uuid_t *mount_id)
int dfs_cache_get_tgt_share(char *path, const struct dfs_cache_tgt_iterator *it, char **share,
char **prefix)
{
char *s, sep, *p;
size_t len;
size_t plen1, plen2;
char sep;
char *target_share, *ppath;
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;
*share = NULL;
*prefix = NULL;
sep = it->it_name[0];
if (sep != '\\' && sep != '/')
return -EINVAL;
s = strchr(it->it_name + 1, sep);
if (!s)
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 target node */
s = strchrnul(s + 1, sep);
/* point to prefix in DFS referral path */
dfsref_ppath = path + it->it_path_consumed;
dfsref_ppath += strspn(dfsref_ppath, "/\\");
/* extract target share */
*share = kstrndup(it->it_name, s - it->it_name, GFP_KERNEL);
if (!*share)
return -ENOMEM;
target_pplen = strlen(target_ppath);
dfsref_pplen = strlen(dfsref_ppath);
/* skip separator */
if (*s)
s++;
/* point to prefix in DFS path */
p = path + it->it_path_consumed;
if (*p == sep)
p++;
/* merge prefix paths from DFS path and target node */
plen1 = it->it_name + strlen(it->it_name) - s;
plen2 = path + strlen(path) - p;
if (plen1 || plen2) {
len = plen1 + plen2 + 2;
*prefix = kmalloc(len, GFP_KERNEL);
if (!*prefix) {
kfree(*share);
*share = NULL;
/* 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;
}
if (plen1)
scnprintf(*prefix, len, "%.*s%c%.*s", (int)plen1, s, sep, (int)plen2, p);
else
strscpy(*prefix, p, len);
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;
}