linux-kernel - [PATCH 1/3] ext4: treat end of range as exclusive in ext4_zero

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Message-Id: <9ae3bf53e81554cec3e609de8e8939b90966f7ab.1695987265.git.ojaswin@linux.ibm.com>
Date:   Fri, 29 Sep 2023 19:40:43 +0530
From:   Ojaswin Mujoo <ojaswin@...ux.ibm.com>
To:     linux-ext4@...r.kernel.org, "Theodore Ts'o" <tytso@....edu>
Cc:     Ritesh Harjani <ritesh.list@...il.com>,
        linux-kernel@...r.kernel.org, Jan Kara <jack@...e.cz>
Subject: [PATCH 1/3] ext4: treat end of range as exclusive in ext4_zero_range()

The call to filemap_write_and_wait_range() assumes the range passed to be
inclusive, so fix the call to make sure we follow that.

Signed-off-by: Ojaswin Mujoo <ojaswin@...ux.ibm.com>
---
 fs/ext4/extents.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index e4115d338f10..c79b4c25afc4 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -4522,7 +4522,8 @@ static long ext4_zero_range(struct file *file, loff_t offset,
 	 * Round up offset. This is not fallocate, we need to zero out
 	 * blocks, so convert interior block aligned part of the range to
 	 * unwritten and possibly manually zero out unaligned parts of the
-	 * range.
+	 * range. Here, start and partial_begin are inclusive, end and
+	 * partial_end are exclusive.
 	 */
 	start = round_up(offset, 1 << blkbits);
 	end = round_down((offset + len), 1 << blkbits);
@@ -4608,7 +4609,7 @@ static long ext4_zero_range(struct file *file, loff_t offset,
 		 * disk in case of crash before zeroing trans is committed.
 		 */
 		if (ext4_should_journal_data(inode)) {
-			ret = filemap_write_and_wait_range(mapping, start, end);
+			ret = filemap_write_and_wait_range(mapping, start, end - 1);
 			if (ret) {
 				filemap_invalidate_unlock(mapping);
 				goto out_mutex;
-- 
2.39.3