Commit 13a6e42a authored by Steve French's avatar Steve French
Browse files

[CIFS] add mount option to send mandatory rather than advisory locks 



Some applications/subsystems require mandatory byte range locks
(as is used for Windows/DOS/OS2 etc). Sending advisory (posix style)
byte range lock requests (instead of mandatory byte range locks) can
lead to problems for these applications (which expect that other
clients be prevented from writing to portions of the file which
they have locked and are updating).  This mount option allows
mounting cifs with the new mount option "forcemand" (or
"forcemandatorylock") in order to have the cifs client use mandatory
byte range locks (ie SMB/CIFS/Windows/NTFS style locks) rather than
posix byte range lock requests, even if the server would support
posix byte range lock requests.  This has no effect if the server
does not support the CIFS Unix Extensions (since posix style locks
require support for the CIFS Unix Extensions), but for mounts
to Samba servers this can be helpful for Wine and applications
that require mandatory byte range locks.

Acked-by: default avatarJeff Layton <jlayton@redhat.com>
CC: Alexander Bokovoy <ab@samba.org>
Signed-off-by: default avatarSteve French <sfrench@us.ibm.com>
parent d5c5605c

fs/cifs/CHANGES

+6 −0
Original line number Diff line number Diff line 
Version 1.56

------------

Add "forcemandatorylock" mount option to allow user to use mandatory

rather than posix (advisory) byte range locks, even though server would

support posix byte range locks.



Version 1.55

------------

Various fixes to make delete of open files behavior more predictable

fs/cifs/README

+11 −1
Original line number Diff line number Diff line
@@ -463,9 +463,19 @@ A partial list of the supported mount options follows: 
		with cifs style mandatory byte range locks (and most

		cifs servers do not yet support requesting advisory

		byte range locks).

 forcemandatorylock Even if the server supports posix (advisory) byte range

		locking, send only mandatory lock requests.  For some

		(presumably rare) applications, originally coded for

		DOS/Windows, which require Windows style mandatory byte range

		locking, they may be able to take advantage of this option,

		forcing the cifs client to only send mandatory locks

		even if the cifs server would support posix advisory locks.

		"forcemand" is accepted as a shorter form of this mount

		option.

 nodfs          Disable DFS (global name space support) even if the

		server claims to support it.  This can help work around

		a problem with parsing of DFS paths with Samba 3.0.24 server.

		a problem with parsing of DFS paths with Samba server

		versions 3.0.24 and 3.0.25.

 remount        remount the share (often used to change from ro to rw mounts

	        or vice versa)

 cifsacl        Report mode bits (e.g. on stat) based on the Windows ACL for

fs/cifs/cifs_fs_sb.h

+3 −2
Original line number Diff line number Diff line
@@ -31,6 +31,7 @@ 
#define CIFS_MOUNT_OVERR_UID    0x400 /* override uid returned from server    */

#define CIFS_MOUNT_OVERR_GID    0x800 /* override gid returned from server    */

#define CIFS_MOUNT_DYNPERM      0x1000 /* allow in-memory only mode setting   */

#define CIFS_MOUNT_NOPOSIXBRL   0x2000 /* mandatory not posix byte range lock */



struct cifs_sb_info {

	struct cifsTconInfo *tcon;	/* primary mount */

fs/cifs/cifsfs.h

+1 −1
Original line number Diff line number Diff line
@@ -101,5 +101,5 @@ extern long cifs_ioctl(struct file *filep, unsigned int cmd, unsigned long arg); 
extern const struct export_operations cifs_export_ops;

#endif /* EXPERIMENTAL */



#define CIFS_VERSION   "1.55"

#define CIFS_VERSION   "1.5666666"

#endif				/* _CIFSFS_H */

fs/cifs/connect.c

+14 −0
Original line number Diff line number Diff line
@@ -89,6 +89,7 @@ struct smb_vol { 
	bool nullauth:1;   /* attempt to authenticate with null user */

	bool nocase:1;     /* request case insensitive filenames */

	bool nobrl:1;      /* disable sending byte range locks to srv */

	bool mand_lock:1;  /* send mandatory not posix byte range lock reqs */

	bool seal:1;       /* request transport encryption on share */

	bool nodfs:1;      /* Do not request DFS, even if available */

	bool local_lease:1; /* check leases only on local system, not remote */
@@ -1246,6 +1247,17 @@ cifs_parse_mount_options(char *options, const char *devname, 
			if (vol->file_mode ==

				(S_IALLUGO & ~(S_ISUID | S_IXGRP)))

				vol->file_mode = S_IALLUGO;

		} else if (strnicmp(data, "forcemandatorylock", 9) == 0) {

			/* will take the shorter form "forcemand" as well */

			/* This mount option will force use of mandatory

			  (DOS/Windows style) byte range locks, instead of

			  using posix advisory byte range locks, even if the

			  Unix extensions are available and posix locks would

			  be supported otherwise. If Unix extensions are not

			  negotiated this has no effect since mandatory locks

			  would be used (mandatory locks is all that those

			  those servers support) */

			vol->mand_lock = 1;

		} else if (strnicmp(data, "setuids", 7) == 0) {

			vol->setuids = 1;

		} else if (strnicmp(data, "nosetuids", 9) == 0) {
@@ -2150,6 +2162,8 @@ static void setup_cifs_sb(struct smb_vol *pvolume_info, 
		cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_UNX_EMUL;

	if (pvolume_info->nobrl)

		cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_NO_BRL;

	if (pvolume_info->mand_lock)

		cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_NOPOSIXBRL;

	if (pvolume_info->cifs_acl)

		cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_CIFS_ACL;

	if (pvolume_info->override_uid)

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