2015-07-24 06:58:00

by Eryu Guan

Subject: [PATCH] ext4: update c/mtime on truncate up

Commit 3da40c7b0898 ("ext4: only call ext4_truncate when size <= isize")
introduced a bug that c/mtime is not updated on truncate up.

Fix the issue by setting c/mtime explicitly in the truncate up case.

Note that ftruncate(2) is not affected, so you won't see this bug using
truncate(1) and xfs_io(1).

Signed-off-by: Zirong Lang <[email protected]>
Signed-off-by: Eryu Guan <[email protected]>
---
fs/ext4/inode.c | 8 ++++++++
1 file changed, 8 insertions(+)

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index cecf9aa..2442eb0 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -4725,6 +4725,14 @@ int ext4_setattr(struct dentry *dentry, struct iattr *attr)
error = ext4_orphan_add(handle, inode);
orphan = 1;
}
+ /*
+ * Update c/mtime on truncate up, ext4_truncate() will
+ * update c/mtime in shrink case below
+ */
+ if (!shrink) {
+ inode->i_mtime = ext4_current_time(inode);
+ inode->i_ctime = inode->i_mtime;
+ }
down_write(&EXT4_I(inode)->i_data_sem);
EXT4_I(inode)->i_disksize = attr->ia_size;
rc = ext4_mark_inode_dirty(handle, inode);
--
1.8.3.1

2015-07-28 19:09:45

by Theodore Ts'o

Subject: Re: [PATCH] ext4: update c/mtime on truncate up

On Fri, Jul 24, 2015 at 02:56:38PM +0800, Eryu Guan wrote:
> Commit 3da40c7b0898 ("ext4: only call ext4_truncate when size <= isize")
> introduced a bug that c/mtime is not updated on truncate up.
>
> Fix the issue by setting c/mtime explicitly in the truncate up case.
>
> Note that ftruncate(2) is not affected, so you won't see this bug using
> truncate(1) and xfs_io(1).
>
> Signed-off-by: Zirong Lang <[email protected]>
> Signed-off-by: Eryu Guan <[email protected]>

Applied, thanks.

- Ted