> When VFAT_FS_DUALNAMES is disabled we avoid the creation of 8.3 short > filenames for files on VFAT filesystems that require a long name. The > patch uses a pattern of 11 bytes in the directory entry which contains > invalid characters such that it cannot be considered to be a valid short > filename. > > Signed-off-by: Andrew Tridgell <tridge@xxxxxxxxx> > Acked-by: Dave Kleikamp <shaggy@xxxxxxxxxxxxxxxxxx> > Acked-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx> > --- > fs/fat/Kconfig | 20 +++++++++++++++++ > fs/fat/dir.c | 15 ++++++------- > fs/fat/namei_vfat.c | 59 +++++++++++++++++++++++++++++++++++++++++++++++++++ > 3 files changed, 86 insertions(+), 8 deletions(-) > > diff --git a/fs/fat/Kconfig b/fs/fat/Kconfig > index 182f9ff..907a5de 100644 > --- a/fs/fat/Kconfig > +++ b/fs/fat/Kconfig > @@ -74,6 +74,26 @@ config VFAT_FS > To compile this as a module, choose M here: the module will be called > vfat. > > +config VFAT_FS_DUALNAMES > + bool "VFAT dual names support" > + depends on VFAT_FS Defaults should be back-compatible. > + > + Users considering enabling this option should consider the implications > + of any patents that may exist on dual filenames in VFAT. > + > + If unsure, say N Say Y. Users considering disabling this should understand that filesystem they write to will not be valid vfat filesystems, and may trigger bugs in some devices. > +#ifndef CONFIG_VFAT_FS_DUALNAMES > +/* > + * build a 11 byte 8.3 buffer which is not a short filename. We want 11 > + * bytes which: > + * - will be seen as a constant string to all APIs on Linux and Windows > + * - cannot be matched with wildcard patterns > + * - cannot be used to access the file > + * - has a low probability of collision within a directory > + * - has an invalid 3 byte extension > + * - contains at least one non-space and non-nul byte > + */ What happens on collision? With 60000 entries in directory, there will be 50% chance of collision. BAD. Why not use something like position in directory instead of random number? Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
