Hi Ted,
The following patch fixes the reported issue.
From f4e156cef119f3ffcc56874da4fb9299cc14f68e Mon Sep 17 00:00:00 2001
From: Theodore Ts'o <tytso@xxxxxxx>
Date: Tue, 7 Mar 2023 23:06:59 -0500
Subject: [PATCH] ext4: swap i_disksize when swaping the boot loader inode
Normally well-behaved of EXT4_IOC_SWAP_BOOT won't actually try to
write to the either inode after using the ioctl, but if they do, the
fact that we're not swapping ei->i_disksize as well as inode->i_size
can trigger warnings.
Link: https://bugzilla.kernel.org/show_bug.cgi?id=217159
Signed-off-by: Theodore Ts'o <tytso@xxxxxxx>
---
fs/ext4/ioctl.c | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)
diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c
index 2e8c34036313..e552c5db0c95 100644
--- a/fs/ext4/ioctl.c
+++ b/fs/ext4/ioctl.c
@@ -329,9 +329,13 @@ static void swap_inode_data(struct inode *inode1, struct inode *inode2)
Shall we drop the redundant assignments 'swap(ei1->i_disksize,
ei2->i_disksize);' ?
ext4_es_remove_extent(inode1, 0, EXT_MAX_BLOCKS);
ext4_es_remove_extent(inode2, 0, EXT_MAX_BLOCKS);
- isize = i_size_read(inode1);
- i_size_write(inode1, i_size_read(inode2));
- i_size_write(inode2, isize);
+ /*
+ * Both inodes are locked, so we don't need to fool around
+ * with i_size_read() and i_size_write().
+ */
+ isize = inode1->i_size;
+ inode1->i_size = ei1->i_disksize = inode2->i_size;
+ inode2->i_size = ei2->i_disksize = isize;
}
void ext4_reset_inode_seed(struct inode *inode)
