(CCing in the original reporter) On Thu, 2012-07-05 at 18:38 +1000, Andrew Bartlett wrote: > When we do a readdir() in CIFS, we are potentially efficiently > collecting a great deal of current, catchable stat information. > > It is important that we always keep the dentry cache current for two > reasons: > - the information may have changed (within the actime timeout). > - if we still have a dentry cache value after that timeout, it is quite > expensive (1xRTT per entry) to find out if it was still correct. > > This hits folks who are using CIFS over a WAN very badly. For example > on an emulated 50ms delay I would have ls --color complete in .1 > seconds, and a second run take 4.5 seconds, as each stat() (for the > colouring) would create a trans2 query_path_info query for each file, > right after getting the same information in the trans2 find_first2. > > This patch implements the simplest approach, I would welcome a > correction on if there is a better approach than d_drop() and dput(). > > Tested on 3.4.4-3.cifsrevalidate.fc17.i686 with a 50ms WANem emulated > WAN against Samba 4.0 beta3. > > Thanks, > > Andrew Bartlett -- Andrew Bartlett http://samba.org/~abartlet/ Authentication Developer, Samba Team http://samba.org -- To unsubscribe from this list: send the line "unsubscribe linux-cifs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
