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cifs: lower default wsize when unix extensions are not used

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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: Nick Davis <phireph0x@yahoo.com>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <smfrench@gmail.com>
This commit is contained in:
Jeff Layton 2012-01-17 16:08:51 -05:00 committed by Steve French
parent f5fffcee27
commit ce91acb3ac
1 changed files with 19 additions and 4 deletions
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23
fs/cifs/connect.c
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@ -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))