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    Subject[122/129] cifs: lower default wsize when unix extensions are not used
    3.2-stable review patch.  If anyone has any objections, please let me know.

    ------------------
    Content-Length: 2260
    Lines: 60

    From: Jeff Layton <jlayton@redhat.com>

    commit ce91acb3acae26f4163c5a6f1f695d1a1e8d9009 upstream.

    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: 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>
    Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

    ---
    fs/cifs/connect.c | 23 +++++++++++++++++++----
    1 file changed, 19 insertions(+), 4 deletions(-)

    --- a/fs/cifs/connect.c
    +++ b/fs/cifs/connect.c
    @@ -2914,18 +2914,33 @@ void cifs_setup_cifs_sb(struct smb_vol *
    #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))



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