[CIFS] Make cifs default wsize match what we actually want to send (52K

typically - header + 13 pages).

Forgetting to set wsize on the mount command costs more than 10% on large
write (can be much more) so this makes a saner default.  We still shrink
this default smaller if server can not support it.

Signed-off-by: Steve French <sfrench@us.ibm.com>

1 files changed, 9 insertions, 1 deletions

diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index 88f60aa52058..eae306fa24b2 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -1785,7 +1785,15 @@ cifs_mount(struct super_block *sb, struct cifs_sb_info *cifs_sb,
                 } else if(volume_info.wsize)
                         cifs_sb->wsize = volume_info.wsize;
                 else
-                        cifs_sb->wsize = CIFSMaxBufSize; /* default */
+                        cifs_sb->wsize = 
+                                min(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 < PAGE_CACHE_SIZE) {
                         cifs_sb->rsize = PAGE_CACHE_SIZE; 
                         /* Windows ME does this */