From: zhongjubin <zhongjubin@xxxxxxxxxx> Syscall truncate() never updates m/ctime even if the file size is changed. However, this is incorrect according to man file: truncate (2): If the size changed, then the st_ctime and st_mtime fields (respectively, time of last status change and time of last modification; see stat(2)) for the file are updated, and the set-user-ID and set-group-ID mode bits may be cleared. Check file size before do_truncate() to fix this. Signed-off-by: zhongjubin <zhongjubin@xxxxxxxxxx> --- fs/open.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/fs/open.c b/fs/open.c index f732fb94600c..02404b759c2e 100644 --- a/fs/open.c +++ b/fs/open.c @@ -106,8 +106,11 @@ long vfs_truncate(const struct path *path, loff_t length) goto put_write_and_out; error = security_path_truncate(path); - if (!error) - error = do_truncate(mnt_userns, path->dentry, length, 0, NULL); + if (error) + goto put_write_and_out; + + if (i_size_read(inode) != length) + error = do_truncate(mnt_userns, path->dentry, length, ATTR_MTIME | ATTR_CTIME, NULL); put_write_and_out: put_write_access(inode); -- 2.12.3
