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Commit ce91acb3 authored by Jeff Layton's avatar Jeff Layton Committed by Steve French
Browse files

cifs: lower default wsize when unix extensions are not used 



We've had some reports of servers (namely, the Solaris in-kernel CIFS
server) that don't deal properly with writes that are "too large" even
though they set CAP_LARGE_WRITE_ANDX. Change the default to better
mirror what windows clients do.

Cc: stable@vger.kernel.org
Cc: Pavel Shilovsky <piastry@etersoft.ru>
Reported-by: default avatarNick Davis <phireph0x@yahoo.com>
Signed-off-by: default avatarJeff Layton <jlayton@redhat.com>
Signed-off-by: default avatarSteve French <smfrench@gmail.com>
parent f5fffcee

fs/cifs/connect.c

+19 −4
Original line number Diff line number Diff line
@@ -2930,18 +2930,33 @@ void cifs_setup_cifs_sb(struct smb_vol *pvolume_info, 
#define CIFS_DEFAULT_IOSIZE (1024 * 1024)



/*

 * Windows only supports a max of 60k reads. Default to that when posix

 * extensions aren't in force.

 * Windows only supports a max of 60kb reads and 65535 byte writes. Default to

 * those values when posix extensions aren't in force. In actuality here, we

 * use 65536 to allow for a write that is a multiple of 4k. Most servers seem

 * to be ok with the extra byte even though Windows doesn't send writes that

 * are that large.

 *

 * Citation:

 *

 * http://blogs.msdn.com/b/openspecification/archive/2009/04/10/smb-maximum-transmit-buffer-size-and-performance-tuning.aspx

 */

#define CIFS_DEFAULT_NON_POSIX_RSIZE (60 * 1024)

#define CIFS_DEFAULT_NON_POSIX_WSIZE (65536)



static unsigned int

cifs_negotiate_wsize(struct cifs_tcon *tcon, struct smb_vol *pvolume_info)

{

	__u64 unix_cap = le64_to_cpu(tcon->fsUnixInfo.Capability);

	struct TCP_Server_Info *server = tcon->ses->server;

	unsigned int wsize = pvolume_info->wsize ? pvolume_info->wsize :

				CIFS_DEFAULT_IOSIZE;

	unsigned int wsize;



	/* start with specified wsize, or default */

	if (pvolume_info->wsize)

		wsize = pvolume_info->wsize;

	else if (tcon->unix_ext && (unix_cap & CIFS_UNIX_LARGE_WRITE_CAP))

		wsize = CIFS_DEFAULT_IOSIZE;

	else

		wsize = CIFS_DEFAULT_NON_POSIX_WSIZE;



	/* can server support 24-bit write sizes? (via UNIX extensions) */

	if (!tcon->unix_ext || !(unix_cap & CIFS_UNIX_LARGE_WRITE_CAP))