Allow mknod and mkfifo on SMB2/SMB3 mounts
The "sfu" mount option did not work on SMB2/SMB3 mounts.
With these changes when the "sfu" mount option is passed in
on an smb2/smb2.1/smb3 mount the client can emulate (and
recognize) fifo and device (character and device files).
In addition the "sfu" mount option should not conflict
with "mfsymlinks" (symlink emulation) as we will never
create "sfu" style symlinks, but using "sfu" mount option
will allow us to recognize existing symlinks, created with
Microsoft "Services for Unix" (SFU and SUA).
To enable the "sfu" mount option for SMB2/SMB3 the calling
syntax of the generic cifs/smb2/smb3 sync_read and sync_write
protocol dependent function needed to be changed (we
don't have a file struct in all cases), but this actually
ended up simplifying the code a little.
Signed-off-by: Steve French <smfrench@gmail.com>
diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index 239e1fb..d8eb6a74 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -3239,10 +3239,20 @@
}
if (pvolume_info->mfsymlinks) {
if (pvolume_info->sfu_emul) {
- cifs_dbg(VFS, "mount option mfsymlinks ignored if sfu mount option is used\n");
- } else {
- cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_MF_SYMLINKS;
+ /*
+ * Our SFU ("Services for Unix" emulation does not allow
+ * creating symlinks but does allow reading existing SFU
+ * symlinks (it does allow both creating and reading SFU
+ * style mknod and FIFOs though). When "mfsymlinks" and
+ * "sfu" are both enabled at the same time, it allows
+ * reading both types of symlinks, but will only create
+ * them with mfsymlinks format. This allows better
+ * Apple compatibility (probably better for Samba too)
+ * while still recognizing old Windows style symlinks.
+ */
+ cifs_dbg(VFS, "mount options mfsymlinks and sfu both enabled\n");
}
+ cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_MF_SYMLINKS;
}
if ((pvolume_info->cifs_acl) && (pvolume_info->dynperm))