commit 5750676b64 upstream.
If dedupe of an EOF block is not constrainted to match against only
other EOF blocks with the same EOF offset into the block, it can
match against any other block that has the same matching initial
bytes in it, even if the bytes beyond EOF in the source file do
not match.
Fix this by constraining the EOF block matching to only match
against other EOF blocks that have identical EOF offsets and data.
This allows "whole file dedupe" to continue to work without allowing
eof blocks to randomly match against partial full blocks with the
same data.
Reported-by: Ansgar Lößer <ansgar.loesser@tu-darmstadt.de>
Fixes: 1383a7ed67 ("vfs: check file ranges before cloning files")
Link: https://lore.kernel.org/linux-fsdevel/a7c93559-4ba1-df2f-7a85-55a143696405@tu-darmstadt.de/
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Complete the migration by moving the file remapping helper functions out
of read_write.c and into remap_range.c. This reduces the clutter in the
first file and (eventually) will make it so that we can compile out the
second file if it isn't needed.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
I would like to move all the generic helpers for the vfs remap range
functionality (aka clonerange and dedupe) into a separate file so that
they won't be scattered across the vfs and the mm subsystems. The
eventual goal is to be able to deselect remap_range.c if none of the
filesystems need that code, but the tricky part here is picking a
stable(ish) part of the merge window to rearrange code.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
