Corinna Vinschen wrote:
[...]
Also, coreutils currently only sorts large directories, but cygwin reports
directory st_size as 0 regardless of directory size, so there is no way to
identify large directories up front.
Not quite. Did you call `ls -s' on cygwin's / directory lately? A snippet
from mine on one of my machines look like this:
160 drwxrwx---+ 1 corinna vinschen 163840 Dec 16 10:13 bin
0 drwxrwx---+ 1 corinna vinschen 0 Apr 15 2008 cygdrive
0 drwxrwx---+ 1 corinna vinschen 0 Apr 30 2008 dev
12 drwxrwx---+ 1 corinna vinschen 12288 Dec 15 11:15 etc
4 drwxr-xr-x+ 1 corinna vinschen 4096 Jul 4 10:41 home
40 drwxrwx---+ 1 corinna vinschen 40960 Dec 8 11:58 lib
0 dr-xr-xr-x 8 corinna vinschen 0 Dec 1 2006 proc
0 drwxrwx---+ 1 corinna vinschen 0 Apr 15 2008 sbin
4 drwxrwxrwt+ 1 corinna vinschen 4096 Dec 15 16:35 tmp
4 drwxrwx---+ 1 corinna vinschen 4096 Dec 8 11:54 usr
0 drwxr-xr-x+ 1 SYSTEM Administrators 0 May 21 2008 var
The size of a directory which you just created is 0. But big
directories (like /bin), or directories which once were big (like /tmp)
have a size which is a multiple of 4K. This size is what's returned by
the NT function NtQueryInformationFile. I assume that a directory is
created with one block in a pre-allocated area in the MFT or so, which
explains size 0. When the dir grows, then normal FS blocks are added,
so the size grows beyond 0. But actualyy I have no idea, so it could be
entirely different. :)
On my XP SP2, st_size is always 0, even for large and fragmented
directories.
Are there any file systems accessed by cygwin where sorting readdir()
results into inode order, rather than visiting contents in directory
listing or name order, provides a speedup by allowing less disk seek time
(or put another way, do the inode numbers presented by Cygwin for local
NTFS disks match disk seek order)? Conversely, are there any file systems
where taking the time to sort readdir() results is provably a waste (for
example, a ramdisk, where seek time is instant regardless of inode, or FAT
and NFS where inode numbers are synthesized with no correlation to disk
layout,
Interesting question. NTFS and FAT filesystems are name-sorted by
default. AFAIK directory changes on FAT are done in-memory, resorted,
and then written back as a whole block to disk.
XP does not sort a FAT directory.
Does this probably depend on Windows version?
Christian
--
Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple
Problem reports: http://cygwin.com/problems.html
Documentation: http://cygwin.com/docs.html
FAQ: http://cygwin.com/faq/
