smb: client: handle lack of FSCTL_GET_REPARSE_POINT support

As per MS-FSA 2.1.5.10.14, support for FSCTL_GET_REPARSE_POINT is
optional and if the server doesn't support it,
STATUS_INVALID_DEVICE_REQUEST must be returned for the operation.

If we find files with reparse points and we can't read them due to
lack of client or server support, just ignore it and then treat them
as regular files or junctions.

Fixes: 5f71ebc41294 ("smb: client: parse reparse point flag in create response")
Reported-by: Sebastian Steinbeisser <Sebastian.Steinbeisser@lrz.de>
Tested-by: Sebastian Steinbeisser <Sebastian.Steinbeisser@lrz.de>
Acked-by: Tom Talpey <tom@talpey.com>
Signed-off-by: Paulo Alcantara (Red Hat) <pc@manguebit.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

diff --git a/fs/smb/client/inode.c b/fs/smb/client/inode.c
index 4a8aa1de95223dfc487e577e476be18d677b6477..dd0afa23734c8d7d1aa14a0a6fee7ba2cf9c10c5 100644 (file)
--- a/fs/smb/client/inode.c
+++ b/fs/smb/client/inode.c
@@ -1042,13 +1042,26 @@ static int reparse_info_to_fattr(struct cifs_open_info_data *data,
        }
 
        rc = -EOPNOTSUPP;
-       switch ((data->reparse.tag = tag)) {
-       case 0: /* SMB1 symlink */
+       data->reparse.tag = tag;
+       if (!data->reparse.tag) {
                if (server->ops->query_symlink) {
                        rc = server->ops->query_symlink(xid, tcon,
                                                        cifs_sb, full_path,
                                                        &data->symlink_target);
                }
+               if (rc == -EOPNOTSUPP)
+                       data->reparse.tag = IO_REPARSE_TAG_INTERNAL;
+       }
+
+       switch (data->reparse.tag) {
+       case 0: /* SMB1 symlink */
+               break;
+       case IO_REPARSE_TAG_INTERNAL:
+               rc = 0;
+               if (le32_to_cpu(data->fi.Attributes) & ATTR_DIRECTORY) {
+                       cifs_create_junction_fattr(fattr, sb);
+                       goto out;
+               }
                break;
        case IO_REPARSE_TAG_MOUNT_POINT:
                cifs_create_junction_fattr(fattr, sb);

diff --git a/fs/smb/client/reparse.c b/fs/smb/client/reparse.c
index a0ffbda90733170bf6c80267f29c90e9fb49d62f..689d8a506d4593caa5952c390c4b0efdbdab06cf 100644 (file)
--- a/fs/smb/client/reparse.c
+++ b/fs/smb/client/reparse.c
@@ -505,6 +505,10 @@ bool cifs_reparse_point_to_fattr(struct cifs_sb_info *cifs_sb,
        }
 
        switch (tag) {
+       case IO_REPARSE_TAG_INTERNAL:
+               if (!(fattr->cf_cifsattrs & ATTR_DIRECTORY))
+                       return false;
+               fallthrough;
        case IO_REPARSE_TAG_DFS:
        case IO_REPARSE_TAG_DFSR:
        case IO_REPARSE_TAG_MOUNT_POINT:

diff --git a/fs/smb/client/reparse.h b/fs/smb/client/reparse.h
index 6b55d1df9e2f844f04b8469823ca5d370589c871..2c0644bc4e65a7e1acaed6f5415f917d5b8a62d5 100644 (file)
--- a/fs/smb/client/reparse.h
+++ b/fs/smb/client/reparse.h
@@ -12,6 +12,12 @@
 #include "fs_context.h"
 #include "cifsglob.h"
 
+/*
+ * Used only by cifs.ko to ignore reparse points from files when client or
+ * server doesn't support FSCTL_GET_REPARSE_POINT.
+ */
+#define IO_REPARSE_TAG_INTERNAL ((__u32)~0U)
+
 static inline dev_t reparse_nfs_mkdev(struct reparse_posix_data *buf)
 {
        u64 v = le64_to_cpu(*(__le64 *)buf->DataBuffer);
@@ -78,10 +84,19 @@ static inline u32 reparse_mode_wsl_tag(mode_t mode)
 static inline bool reparse_inode_match(struct inode *inode,
                                       struct cifs_fattr *fattr)
 {
+       struct cifsInodeInfo *cinode = CIFS_I(inode);
        struct timespec64 ctime = inode_get_ctime(inode);
 
-       return (CIFS_I(inode)->cifsAttrs & ATTR_REPARSE) &&
-               CIFS_I(inode)->reparse_tag == fattr->cf_cifstag &&
+       /*
+        * Do not match reparse tags when client or server doesn't support
+        * FSCTL_GET_REPARSE_POINT.  @fattr->cf_cifstag should contain correct
+        * reparse tag from query dir response but the client won't be able to
+        * read the reparse point data anyway.  This spares us a revalidation.
+        */
+       if (cinode->reparse_tag != IO_REPARSE_TAG_INTERNAL &&
+           cinode->reparse_tag != fattr->cf_cifstag)
+               return false;
+       return (cinode->cifsAttrs & ATTR_REPARSE) &&
                timespec64_equal(&ctime, &fattr->cf_ctime);
 }
 

diff --git a/fs/smb/client/smb2inode.c b/fs/smb/client/smb2inode.c
index 5c02a12251c8486f55095777eedee868282d1a54..062b86a4936fd5a7aed4ef68bb4e6eb50ba8fcb7 100644 (file)
--- a/fs/smb/client/smb2inode.c
+++ b/fs/smb/client/smb2inode.c
@@ -930,6 +930,8 @@ int smb2_query_path_info(const unsigned int xid,
 
        switch (rc) {
        case 0:
+               rc = parse_create_response(data, cifs_sb, &out_iov[0]);
+               break;
        case -EOPNOTSUPP:
                /*
                 * BB TODO: When support for special files added to Samba