Re: Possible coding issue in udf??

From: Andreas Schwab
Date: Sun May 15 2011 - 13:14:23 EST


Alex Davis <alex14641@xxxxxxxxx> writes:

> In fs/udf/inode.c, line 1455, linux 2.6.35, there is the following code:
>
> udfperms = ((inode->i_mode & S_IRWXO)) |
> ((inode->i_mode & S_IRWXG) << 2) |
> ((inode->i_mode & S_IRWXU) << 4);
>
> Shouldn't we be shifting by 3 bits? i.e:
> udfperms = ((inode->i_mode & S_IRWXO)) |
> ((inode->i_mode & S_IRWXG) << 3) |
> ((inode->i_mode & S_IRWXU) << 6);

udfperms contains three bit fields of 5 bits each, of which 3 bits are
each filled from one of the three RWX parts of i_mode, and 2 bits
(DELETE and CHATTR) are added later. Thus each of the three bit fields
are expanded from 3 to 5 bits, so that the second one needs to be
shifted by 2 and the third one by 4.

Andreas.

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