This is a note to let you know that I've just added the patch titled
fsdax: dedupe should compare the min of two iters' length
to the 6.2-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:
fsdax-dedupe-should-compare-the-min-of-two-iters-length.patch
and it can be found in the queue-6.2 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From e900ba10d15041a6236cc75778cc6e06c3590a58 Mon Sep 17 00:00:00 2001
From: Shiyang Ruan <ruansy.fnst@xxxxxxxxxxx>
Date: Wed, 22 Mar 2023 07:25:58 +0000
Subject: fsdax: dedupe should compare the min of two iters' length
From: Shiyang Ruan <ruansy.fnst@xxxxxxxxxxx>
commit e900ba10d15041a6236cc75778cc6e06c3590a58 upstream.
In an dedupe comparison iter loop, the length of iomap_iter decreases
because it implies the remaining length after each iteration.
The dedupe command will fail with -EIO if the range is larger than one
page size and not aligned to the page size. Also report warning in dmesg:
[ 4338.498374] ------------[ cut here ]------------
[ 4338.498689] WARNING: CPU: 3 PID: 1415645 at fs/iomap/iter.c:16
...
The compare function should use the min length of the current iters,
not the total length.
Link: https://lkml.kernel.org/r/1679469958-2-1-git-send-email-ruansy.fnst@xxxxxxxxxxx
Fixes: 0e79e3736d54 ("fsdax: dedupe: iter two files at the same time")
Signed-off-by: Shiyang Ruan <ruansy.fnst@xxxxxxxxxxx>
Reviewed-by: Darrick J. Wong <djwong@xxxxxxxxxx>
Cc: Dan Williams <dan.j.williams@xxxxxxxxx>
Cc: Jan Kara <jack@xxxxxxx>
Cc: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/dax.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -2022,8 +2022,8 @@ int dax_dedupe_file_range_compare(struct
while ((ret = iomap_iter(&src_iter, ops)) > 0 &&
(ret = iomap_iter(&dst_iter, ops)) > 0) {
- compared = dax_range_compare_iter(&src_iter, &dst_iter, len,
- same);
+ compared = dax_range_compare_iter(&src_iter, &dst_iter,
+ min(src_iter.len, dst_iter.len), same);
if (compared < 0)
return ret;
src_iter.processed = dst_iter.processed = compared;
Patches currently in stable-queue which might be from ruansy.fnst@xxxxxxxxxxx are
queue-6.2/fsdax-unshare-zero-destination-if-srcmap-is-hole-or-unwritten.patch
queue-6.2/fsdax-force-clear-dirty-mark-if-cow.patch
queue-6.2/fsdax-dedupe-should-compare-the-min-of-two-iters-length.patch
