On Wed, 1 Aug 2007, Sergey Vlasov wrote: > On Tue, Jul 31, 2007 at 11:08:37PM +0100, Kostas Peletidis wrote: > > Branden Sletteland wrote: > > > I have also noticed this delay and have through instrumenting code > > > have found that every block in the device gets read in. I never > > > checked if it was something in the df, filesystem, SCSI, or USB > > > subsystems that was causing this. I am usually doing df on USB > > > storage devices formated as FAT 32 w/ and w/o LBA. > > > > > > Branden > > > > > > > > Thanks for your reply Branden. This explains why df would delay for a > > whole minute to terminate normally with a 500GB usb disk attached and > > only for a second or two with a 512MB usb stick attached. Btw both are vfat. > > > > This brings another question though: Why read every single block during > > the first run of df after the partition is mounted? Obviously buffering > > 500GB for fast access is currently out of the question so could it be > > the case that some sanity check was going on? > > Probably the commit 28ec039c21839914389975b896160a815ffd8b83 is the > culprit: > > fat: don't use free_clusters for fat32 > > It seems that the recent Windows changed specification, and it's > undocumented. Windows doesn't update ->free_clusters correctly. > > This patch doesn't use ->free_clusters by default. (instead, add > "usefree" > for forcing to use it) > > Signed-off-by: OGAWA Hirofumi <[EMAIL PROTECTED]> > Cc: Juergen Beisert <[EMAIL PROTECTED]> > Cc: Andreas Schwab <[EMAIL PROTECTED]> > Signed-off-by: Andrew Morton <[EMAIL PROTECTED]> > Signed-off-by: Linus Torvalds <[EMAIL PROTECTED]> > > You can add "usefree" to mount options - it will restore the old > behavior (which can apparently lead to wrong free space reports after > the disk has been used by some Windows versions). Without "usefree" > the vfat code in 2.6.22 will read the whole FAT to count free clusters > on the filesystem.
But reading the whole FAT is very different from reading the entire partition. Alan Stern ------------------------------------------------------------------------- This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now >> http://get.splunk.com/ _______________________________________________ linux-usb-devel@lists.sourceforge.net To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
