Remap reserved posix characters by default (part 3/3)

This is a bigger patch, but its size is mostly due to
a single change for how we check for remapping illegal characters
in file names - a lot of repeated, small changes to
the way callers request converting file names.

The final patch in the series does the following:

1) changes default behavior for cifs to be more intuitive.
Currently we do not map by default to seven reserved characters,
ie those valid in POSIX but not in NTFS/CIFS/SMB3/Windows,
unless a mount option (mapchars) is specified.  Change this
to by default always map and map using the SFM maping
(like the Mac uses) unless the server negotiates the CIFS Unix
Extensions (like Samba does when mounting with the cifs protocol)
when the remapping of the characters is unnecessary.  This should
help SMB3 mounts in particular since Samba will likely be
able to implement this mapping with its new "vfs_fruit" module
as it will be doing for the Mac.
2) if the user specifies the existing "mapchars" mount option then
use the "SFU" (Microsoft Services for Unix, SUA) style mapping of
the seven characters instead.
3) if the user specifies "nomapposix" then disable SFM/MAC style mapping
(so no character remapping would be used unless the user specifies
"mapchars" on mount as well, as above).
4) change all the places in the code that check for the superblock
flag on the mount which is set by mapchars and passed in on all
path based operation and change it to use a small function call
instead to set the mapping type properly (and check for the
mapping type in the cifs unicode functions)

Signed-off-by: Steve French <smfrench@gmail.com>

1 files changed, 9 insertions, 16 deletions

diff --git a/fs/cifs/smb1ops.c b/fs/cifs/smb1ops.c
index 2aca620193c..d2979036a4c 100644
--- a/fs/cifs/smb1ops.c
+++ b/fs/cifs/smb1ops.c
@@ -23,6 +23,7 @@
 #include "cifsproto.h"
 #include "cifs_debug.h"
 #include "cifspdu.h"
+#include "cifs_unicode.h"
 
 /*
  * An NT cancel request header looks just like the original request except:
@@ -530,13 +531,11 @@ cifs_is_path_accessible(const unsigned int xid, struct cifs_tcon *tcon,
 
 	rc = CIFSSMBQPathInfo(xid, tcon, full_path, file_info,
 			      0 /* not legacy */, cifs_sb->local_nls,
-			      cifs_sb->mnt_cifs_flags &
-				CIFS_MOUNT_MAP_SPECIAL_CHR);
+			      cifs_remap(cifs_sb));
 
 	if (rc == -EOPNOTSUPP || rc == -EINVAL)
 		rc = SMBQueryInformation(xid, tcon, full_path, file_info,
-				cifs_sb->local_nls, cifs_sb->mnt_cifs_flags &
-				  CIFS_MOUNT_MAP_SPECIAL_CHR);
+				cifs_sb->local_nls, cifs_remap(cifs_sb));
 	kfree(file_info);
 	return rc;
 }
@@ -552,8 +551,7 @@ cifs_query_path_info(const unsigned int xid, struct cifs_tcon *tcon,
 
 	/* could do find first instead but this returns more info */
 	rc = CIFSSMBQPathInfo(xid, tcon, full_path, data, 0 /* not legacy */,
-			      cifs_sb->local_nls, cifs_sb->mnt_cifs_flags &
-						CIFS_MOUNT_MAP_SPECIAL_CHR);
+			      cifs_sb->local_nls, cifs_remap(cifs_sb));
 	/*
 	 * BB optimize code so we do not make the above call when server claims
 	 * no NT SMB support and the above call failed at least once - set flag
@@ -562,8 +560,7 @@ cifs_query_path_info(const unsigned int xid, struct cifs_tcon *tcon,
 	if ((rc == -EOPNOTSUPP) || (rc == -EINVAL)) {
 		rc = SMBQueryInformation(xid, tcon, full_path, data,
 					 cifs_sb->local_nls,
-					 cifs_sb->mnt_cifs_flags &
-						CIFS_MOUNT_MAP_SPECIAL_CHR);
+					 cifs_remap(cifs_sb));
 		*adjustTZ = true;
 	}
 
@@ -611,8 +608,7 @@ cifs_get_srv_inum(const unsigned int xid, struct cifs_tcon *tcon,
 	 */
 	return CIFSGetSrvInodeNumber(xid, tcon, full_path, uniqueid,
 				     cifs_sb->local_nls,
-				     cifs_sb->mnt_cifs_flags &
-						CIFS_MOUNT_MAP_SPECIAL_CHR);
+				     cifs_remap(cifs_sb));
 }
 
 static int
@@ -703,8 +699,7 @@ cifs_mkdir_setinfo(struct inode *inode, const char *full_path,
 	dosattrs = cifsInode->cifsAttrs|ATTR_READONLY;
 	info.Attributes = cpu_to_le32(dosattrs);
 	rc = CIFSSMBSetPathInfo(xid, tcon, full_path, &info, cifs_sb->local_nls,
-				cifs_sb->mnt_cifs_flags &
-						CIFS_MOUNT_MAP_SPECIAL_CHR);
+				cifs_remap(cifs_sb));
 	if (rc == 0)
 		cifsInode->cifsAttrs = dosattrs;
 }
@@ -720,8 +715,7 @@ cifs_open_file(const unsigned int xid, struct cifs_open_parms *oparms,
 				     oparms->create_options,
 				     &oparms->fid->netfid, oplock, buf,
 				     oparms->cifs_sb->local_nls,
-				     oparms->cifs_sb->mnt_cifs_flags
-						& CIFS_MOUNT_MAP_SPECIAL_CHR);
+				     cifs_remap(oparms->cifs_sb));
 	return CIFS_open(xid, oparms, oplock, buf);
 }
 
@@ -800,8 +794,7 @@ smb_set_file_info(struct inode *inode, const char *full_path,
 	tcon = tlink_tcon(tlink);
 
 	rc = CIFSSMBSetPathInfo(xid, tcon, full_path, buf, cifs_sb->local_nls,
-					cifs_sb->mnt_cifs_flags &
-						CIFS_MOUNT_MAP_SPECIAL_CHR);
+				cifs_remap(cifs_sb));
 	if (rc == 0) {
 		cinode->cifsAttrs = le32_to_cpu(buf->Attributes);
 		goto out;