This is a note to let you know that I've just added the patch titled
fs/remap: constrain dedupe of EOF blocks
to the 5.18-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
fs-remap-constrain-dedupe-of-eof-blocks.patch
and it can be found in the queue-5.18 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 5750676b64a561f7ec920d7c6ba130fc9c7378f3 Mon Sep 17 00:00:00 2001
From: Dave Chinner <dchinner@xxxxxxxxxx>
Date: Wed, 13 Jul 2022 17:49:15 +1000
Subject: fs/remap: constrain dedupe of EOF blocks
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From: Dave Chinner <dchinner@xxxxxxxxxx>
commit 5750676b64a561f7ec920d7c6ba130fc9c7378f3 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@xxxxxxxxxxxxxxx>
Fixes: 1383a7ed6749 ("vfs: check file ranges before cloning files")
Link: https://lore.kernel.org/linux-fsdevel/a7c93559-4ba1-df2f-7a85-55a143696405@xxxxxxxxxxxxxxx/
Signed-off-by: Dave Chinner <dchinner@xxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/remap_range.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
--- a/fs/remap_range.c
+++ b/fs/remap_range.c
@@ -71,7 +71,8 @@ static int generic_remap_checks(struct f
* Otherwise, make sure the count is also block-aligned, having
* already confirmed the starting offsets' block alignment.
*/
- if (pos_in + count == size_in) {
+ if (pos_in + count == size_in &&
+ (!(remap_flags & REMAP_FILE_DEDUP) || pos_out + count == size_out)) {
bcount = ALIGN(size_in, bs) - pos_in;
} else {
if (!IS_ALIGNED(count, bs))
Patches currently in stable-queue which might be from dchinner@xxxxxxxxxx are
queue-5.18/fs-remap-constrain-dedupe-of-eof-blocks.patch
