kern/106255: [msdosfs] : correct setting of archive flag

[Rene Ladan]

The following reply was made to PR kern/106255; it has been noted by GNATS.

From: Rene Ladan <r.c.ladan at gmail.com>
To: Bruce Evans <bde at zeta.org.au>
Cc: freebsd-gnats-submit at FreeBSD.org,  freebsd-bugs at FreeBSD.org
Subject: Re: kern/106255: [msdosfs] : correct setting of archive flag
Date: Mon, 04 Dec 2006 13:26:53 +0100

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 Bruce Evans schreef:
 > On Sun, 3 Dec 2006, Rene Ladan wrote:
 > 
 >>> Description:
 >> The MSDOS file system has an archive bit in the flags field.  This bit
 >> roughly corresponds to the archive flag on the UFS file system. 
 >> However, it is set the wrong way around: the flag should be set when
 >> the bit is present, and cleared when the bit is absent.
 > 
 > The comment in msdosfs/direntry.h says that ATTR_ARCHIVE means that
 > the file is new or modified (in other words, not archived), while the
 > comment in sys/stat.h says that SF_ARCHIVED means that the file is
 > archived, but I think both mean that it is archived.
 > 
 [patch 1]
 
 > This only fixes the reporting of the flag.  msdosfs still maintains
 > the flag perfectly backwards (except DETIMES() is missing setting of
 > it for for all changes -- I think all changes to metadata except
 > possibly to atimes should set it to be perfectly backwards and clear
 > it to be correct).
 >
 I've attached a new patch which
   * fixes reporting of the flag (as in the previous patch)
   * sets the archive flag in DETIMES() when the file is created
   * cleans up the logic of not supporting setting the archive flag on
 directories (chunk 3)
   * does not set the flag when (vap->va_atime.tv_sec != VNOVAL) or
 (vap->va_mode != VNOVAL) in msdosfs_setattr()
 
 I think that only userland tools should send a 'clear request', as the
 flag only needs to be cleared when the file is backed up.  The kernel
 cannot know when a file has been backed up.
 
 Any comments are welcome.
 
 > Bruce
 > 
 
 Regards,
 Rene
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 --- msdosfs_vnops.c.orig	Sun Dec  3 20:45:24 2006
 +++ msdosfs_vnops.c	Mon Dec  4 12:43:37 2006
 @@ -354,7 +354,7 @@
  		vap->va_birthtime.tv_nsec = 0;
  	}
  	vap->va_flags = 0;
 -	if ((dep->de_Attributes & ATTR_ARCHIVE) == 0)
 +	if (dep->de_Attributes & ATTR_ARCHIVE)
  		vap->va_flags |= SF_ARCHIVED;
  	vap->va_gen = 0;
  	vap->va_blocksize = pmp->pm_bpcluster;
 @@ -431,12 +431,13 @@
  			if (error)
  				return (error);
  		}
 -		if (vap->va_flags & ~SF_ARCHIVED)
 -			return EOPNOTSUPP;
  		if (vap->va_flags & SF_ARCHIVED)
  			dep->de_Attributes &= ~ATTR_ARCHIVE;
 -		else if (!(dep->de_Attributes & ATTR_DIRECTORY))
 -			dep->de_Attributes |= ATTR_ARCHIVE;
 +		else
 +			if (dep->de_Attributes & ATTR_DIRECTORY)
 +				return EOPNOTSUPP;
 +			else 
 +				dep->de_Attributes |= ATTR_ARCHIVE;
  		dep->de_flag |= DE_MODIFIED;
  	}
  
 @@ -506,8 +507,9 @@
  				dep->de_flag &= ~DE_UPDATE;
  				timespec2fattime(&vap->va_mtime, 0,
  				    &dep->de_MDate, &dep->de_MTime, NULL);
 +				dep->de_Attributes |= ATTR_ARCHIVE;
 +				/* only set archive flag when file has changed */
  			}
 -			dep->de_Attributes |= ATTR_ARCHIVE;
  			dep->de_flag |= DE_MODIFIED;
  		}
  	}
 @@ -531,7 +533,6 @@
  				dep->de_Attributes &= ~ATTR_READONLY;
  			else
  				dep->de_Attributes |= ATTR_READONLY;
 -			dep->de_Attributes |= ATTR_ARCHIVE;
  			dep->de_flag |= DE_MODIFIED;
  		}
  	}
 --- denode.h.orig	Thu Oct 26 11:21:07 2006
 +++ denode.h	Mon Dec  4 12:35:00 2006
 @@ -239,6 +239,7 @@
  		timespec2fattime((cre), 0, &(dep)->de_CDate,		\
  		    &(dep)->de_CTime, &(dep)->de_CHun);			\
  		    (dep)->de_flag |= DE_MODIFIED;			\
 +		    (dep)->de_Attributes |= ATTR_ARCHIVE;		\
  	}								\
  	(dep)->de_flag &= ~(DE_UPDATE | DE_CREATE | DE_ACCESS);		\
  } while (0)
 
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