1. 20 2月, 2007 1 次提交
  2. 23 12月, 2006 1 次提交
    • M
      [PATCH] fsstack: Remove inode copy · ba3ff12f
      Michael Halcrow 提交于
      Trevor found a file size problem in eCryptfs in recent kernels, and he
      tracked it down to an fsstack change.
      
      This was the eCryptfs copy_attr_all:
      
      > -void ecryptfs_copy_attr_all(struct inode *dest, const struct inode *src)
      > -{
      > -       dest->i_mode = src->i_mode;
      > -       dest->i_nlink = src->i_nlink;
      > -       dest->i_uid = src->i_uid;
      > -       dest->i_gid = src->i_gid;
      > -       dest->i_rdev = src->i_rdev;
      > -       dest->i_atime = src->i_atime;
      > -       dest->i_mtime = src->i_mtime;
      > -       dest->i_ctime = src->i_ctime;
      > -       dest->i_blkbits = src->i_blkbits;
      > -       dest->i_flags = src->i_flags;
      > -}
      
      This is the fsstack copy_attr_all:
      
      > +void fsstack_copy_attr_all(struct inode *dest, const struct inode *src,
      > +                               int (*get_nlinks)(struct inode *))
      > +{
      > +       if (!get_nlinks)
      > +               dest->i_nlink = src->i_nlink;
      > +       else
      > +               dest->i_nlink = (*get_nlinks)(dest);
      > +
      > +       dest->i_mode = src->i_mode;
      > +       dest->i_uid = src->i_uid;
      > +       dest->i_gid = src->i_gid;
      > +       dest->i_rdev = src->i_rdev;
      > +       dest->i_atime = src->i_atime;
      > +       dest->i_mtime = src->i_mtime;
      > +       dest->i_ctime = src->i_ctime;
      > +       dest->i_blkbits = src->i_blkbits;
      > +       dest->i_flags = src->i_flags;
      > +
      > +       fsstack_copy_inode_size(dest, src);
      > +}
      
      The addition of copy_inode_size breaks eCryptfs, since eCryptfs needs to
      interpolate the file sizes (eCryptfs has extra space in the lower file for
      the header).  The setting of the upper inode size occurs elsewhere in
      eCryptfs, and the new copy_attr_all now undoes what eCryptfs was doing
      right beforehand.
      
      I see three ways of going forward from here.  (1) Something like this patch
      needs to go in (assuming it jives with Unionfs), (2) we need to make a
      change to the fsstack API for more fine-grained control over copying
      attributes (e.g., by also including a callback function for calculating the
      right file size, which will require some more work on both eCryptfs and
      Unionfs), or (3) the fsstack patch on eCryptfs (commit
      0cc72dc7 made on Fri Dec 8 02:36:31 2006
      -0800) needs to be yanked in 2.6.20.
      
      I think the simplest solution, from eCryptfs' perspective, is to just
      remove the inode size copy.
      
      Remove inode size copy in general fsstack attr copy code. Stacked
      filesystems may need to interpolate the inode size, since the file
      size in the lower file may be different than the file size in the
      stacked layer.
      Signed-off-by: NMichael Halcrow <mhalcrow@us.ibm.com>
      Acked-by: NJosef "Jeff" Sipek <jsipek@cs.sunysb.edu>
      Signed-off-by: NAndrew Morton <akpm@osdl.org>
      Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      ba3ff12f
  3. 09 12月, 2006 1 次提交
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