From: Shiyang Ruan <ruansy.fnst@fujitsu.com>
Date: Wed, 22 Mar 2023 07:25:58 +0000
Subject: [PATCH] fsdax: dedupe should compare the min of two iters' length
References: bsc#1012628
Patch-mainline: 6.2.11
Git-commit: e900ba10d15041a6236cc75778cc6e06c3590a58
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@fujitsu.com
Fixes: 0e79e3736d54 ("fsdax: dedupe: iter two files at the same time")
Signed-off-by: Shiyang Ruan <ruansy.fnst@fujitsu.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
fs/dax.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/fs/dax.c b/fs/dax.c
index 3e457a16..9800b93e 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -2022,8 +2022,8 @@ int dax_dedupe_file_range_compare(struct inode *src, loff_t srcoff,
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;
--
2.35.3