Date: Fri, 19 Aug 2011 18:58:55 -0400 (EDT) From: Rick Macklem <rmacklem@uoguelph.ca> To: vadim nuclight <vadim_nuclight@mail.ru> Cc: freebsd-fs@freebsd.org Subject: Re: touch(1) not working on directories in an msdosfs(5) envirement Message-ID: <1303085986.99226.1313794735324.JavaMail.root@erie.cs.uoguelph.ca> In-Reply-To: <slrnj4tnr9.2di5.vadim_nuclight@kernblitz.nuclight.avtf.net>
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Vadim Goncharov wrote: > Hi Rick Macklem! > > On Fri, 19 Aug 2011 15:40:31 -0400 (EDT); Rick Macklem wrote about > 'Re: touch(1) not working on directories in an msdosfs(5) envirement': > > > Yes, FAT file systems do not maintain a directory modify > > time. (The original FAT12,16 structure didn't even have a > > modify time for the root dir.) > > > Just like Windows. > > > This causes issues when a FAT fs is exported via NFS and > > someone was going to experiment with an "in memory only" > > modify time for dirs, to minimize caching issues, but I > > haven't heard back from them lately. > > > Apparently Mac OS X chooses to update the modify time that > > exists on FAT32 file systems, but that isn't Windows compatible. > > What? I've just now created a test directory and changed it's modify > time > in Far Manager on Windows 2000, in a FAT32 partition. In fact it > allows to > change all three directory times, creation and access, too. So, I > conclude, > the FAT supports it. > Well, FAT32 (not the root dir of FAT12 or FAT16) does have a modify time stored on disk for the directory entry for a directory. The case I was thinking of (because that was what affected NFS client caching) was the case where an entry is added to a directory. I just checked that and it does not change the directory's modify time when an entry is added to a directory (at least for Windows7 personal...). I'm not enough of a Windows guy to even know what "Far Manager" is, but I'm not surprised that there is a tool that can change it. msdosfs_setattr() in sys/fs/msdosfs/msdosfs_vnops.c definitely only does it for non-directories: if (vp->v_type != VDIR) { if ((pmp->pm_flags & MSDOSFSMNT_NOWIN95) == 0 && vap->va_atime.tv_sec != VNOVAL) { dep->de_flag &= ~DE_ACCESS; timespec2fattime(&vap->va_atime, 0, &dep->de_ADate, NULL, NULL); } if (vap->va_mtime.tv_sec != VNOVAL) { dep->de_flag &= ~DE_UPDATE; timespec2fattime(&vap->va_mtime, 0, &dep->de_MDate, &dep->de_MTime, NULL); } dep->de_Attributes |= ATTR_ARCHIVE; dep->de_flag |= DE_MODIFIED; } I'm not the author of the above, but I had assumed that it was because Windows doesn't normally update it. Obviously, the above code could easily be changed (although I haven't tested that), if that is now considered correct behaviour. (It might have been because the msdosfs is meant to work for all FAT variants.) rick > -- > WBR, Vadim Goncharov. ICQ#166852181 mailto:vadim_nuclight@mail.ru > [Anti-Greenpeace][Sober FreeBSD > zealot][http://nuclight.livejournal.com] > > _______________________________________________ > freebsd-fs@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-fs > To unsubscribe, send any mail to "freebsd-fs-unsubscribe@freebsd.org"
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