On Wed, 13 Apr 2011 07:43:14 -0400
Jeff Layton <jlayton@xxxxxxxxxx> wrote:
> Now that we can handle larger wsizes in writepages, fix up the
> negotiation of the wsize to allow for that. Make the code default to a
> wsize of (128k - PAGE_CACHE_SIZE). That gives us a size that goes up to
> the max frame size specified in RFC1001.
>
> If CAP_LARGE_WRITE_AND_X isn't set, then set that down to a the largest
> size allowed by the protocol (2^16 - 1), or the specified wsize,
> whichever is smaller.
>
> If a larger wsize is specified, then check to make sure the server
> supports the POSIX extension that allows it to ignore the 128k limit. If
> it doesn't then set it to the default value.
>
> Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx>
> ---
> fs/cifs/connect.c | 62 +++++++++++++++++++++++++++++++++++-----------------
> 1 files changed, 42 insertions(+), 20 deletions(-)
>
> diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
> index 8f737d2..dc4de86 100644
> --- a/fs/cifs/connect.c
> +++ b/fs/cifs/connect.c
> @@ -2600,23 +2600,6 @@ static void setup_cifs_sb(struct smb_vol *pvolume_info,
> else /* default */
> cifs_sb->rsize = CIFSMaxBufSize;
>
> - if (pvolume_info->wsize > PAGEVEC_SIZE * PAGE_CACHE_SIZE) {
> - cERROR(1, "wsize %d too large, using 4096 instead",
> - pvolume_info->wsize);
> - cifs_sb->wsize = 4096;
> - } else if (pvolume_info->wsize)
> - cifs_sb->wsize = pvolume_info->wsize;
> - else
> - cifs_sb->wsize = min_t(const int,
> - PAGEVEC_SIZE * PAGE_CACHE_SIZE,
> - 127*1024);
> - /* old default of CIFSMaxBufSize was too small now
> - that SMB Write2 can send multiple pages in kvec.
> - RFC1001 does not describe what happens when frame
> - bigger than 128K is sent so use that as max in
> - conjunction with 52K kvec constraint on arch with 4K
> - page size */
> -
> if (cifs_sb->rsize < 2048) {
> cifs_sb->rsize = 2048;
> /* Windows ME may prefer this */
> @@ -2694,6 +2677,46 @@ static void setup_cifs_sb(struct smb_vol *pvolume_info,
> "mount option supported");
> }
>
> +/*
> + * default to a wsize of 128k - PAGE_CACHE_SIZE -- one page less than the
> + * largest frame size described in RFC1001. This allows space for the header
> + * without going over that by default.
> + */
> +#define CIFS_MAX_RFC1001_WSIZE (128 * 1024 - PAGE_CACHE_SIZE)
> +
> +/*
> + * It's possible to increase the wsize by setting the wsize parm directly
> + * up to a hard limit of 2^24 - PAGE_CACHE_SIZE. That might make for
> + * "interesting" allocation* problems during write however (as we have to
> + * allocate an array of pointers for the pages).
> + */
> +#define CIFS_MAX_WSIZE ((1<<24) - PAGE_CACHE_SIZE)
> +
> +/* If CAP_LARGE_WRITE_AND_X isn't set, then limit the wsize to 16 bits */
> +#define CIFS_MAX_SMALL_WRITEX_WSIZE (0xffff)
> +
> +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_MAX_RFC1001_WSIZE;
> +
> + /* no CAP_LARGE_WRITE_X? Limit it to 16 bits */
> + if (!(server->capabilities & CAP_LARGE_WRITE_X))
> + wsize = min_t(unsigned int, wsize, CIFS_MAX_SMALL_WRITEX_WSIZE);
> +
> + /* can server support 24-bit write sizes? (via UNIX extensions) */
> + if (tcon->unix_ext && !(unix_cap & CIFS_UNIX_LARGE_WRITE_CAP))
oops, logic bug here -- this should be:
if (!tcon->unix_ext || !(unix_cap & CIFS_UNIX_LARGE_WRITE_CAP))
...I'll fix it in next version...
> + wsize = min_t(unsigned int, wsize, CIFS_MAX_RFC1001_WSIZE);
> +
> + /* hard limit of CIFS_MAX_WSIZE */
> + wsize = min_t(unsigned int, wsize, CIFS_MAX_WSIZE);
> +
> + return wsize;
> +}
> +
> static int
> is_path_accessible(int xid, struct cifs_tcon *tcon,
> struct cifs_sb_info *cifs_sb, const char *full_path)
> @@ -2884,13 +2907,12 @@ try_mount_again:
> cifs_sb->rsize = 1024 * 127;
> cFYI(DBG2, "no very large read support, rsize now 127K");
> }
> - if (!(tcon->ses->capabilities & CAP_LARGE_WRITE_X))
> - cifs_sb->wsize = min(cifs_sb->wsize,
> - (tcon->ses->server->maxBuf - MAX_CIFS_HDR_SIZE));
> if (!(tcon->ses->capabilities & CAP_LARGE_READ_X))
> cifs_sb->rsize = min(cifs_sb->rsize,
> (tcon->ses->server->maxBuf - MAX_CIFS_HDR_SIZE));
>
> + cifs_sb->wsize = cifs_negotiate_wsize(tcon, volume_info);
> +
> remote_path_check:
> /* check if a whole path (including prepath) is not remote */
> if (!rc && tcon) {
--
Jeff Layton <jlayton@xxxxxxxxxx>
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