On Mon 31-12-18 14:48:35, Theodore Ts'o wrote:
> In no-journal mode, we previously used __generic_file_fsync() in
> no-journal mode. This triggers a lockdep warning, and in addition,
> it's not safe to depend on the inode writeback mechanism in the case
> ext4. We can solve both problems by calling ext4_write_inode()
> directly.
>
> Signed-off-by: Theodore Ts'o <tytso@xxxxxxx>
> Cc: stable@xxxxxxxxxx
> ---
> fs/ext4/fsync.c | 13 +++++++++----
> 1 file changed, 9 insertions(+), 4 deletions(-)
>
> diff --git a/fs/ext4/fsync.c b/fs/ext4/fsync.c
> index 26a7fe5c4fd3..87a7ff00ef62 100644
> --- a/fs/ext4/fsync.c
> +++ b/fs/ext4/fsync.c
> @@ -116,8 +116,16 @@ int ext4_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
> goto out;
> }
>
> + ret = file_write_and_wait_range(file, start, end);
> + if (ret)
> + return ret;
> +
> if (!journal) {
> - ret = __generic_file_fsync(file, start, end, datasync);
> + struct writeback_control wbc = {
> + .sync_mode = WB_SYNC_ALL
> + };
> +
> + ret = ext4_write_inode(inode, &wbc);
Going through some older email... How come this is safe Ted?
ext4_write_inode() will not write out metadata buffers associated with the
inode (unlike __generic_file_fsync() which calls sync_mapping_buffers()).
So you probably need to call sync_mapping_buffers() before calling
ext4_write_inode() here?
Honza
> @@ -125,9 +133,6 @@ int ext4_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
> goto out;
> }
>
> - ret = file_write_and_wait_range(file, start, end);
> - if (ret)
> - return ret;
> /*
> * data=writeback,ordered:
> * The caller's filemap_fdatawrite()/wait will sync the data.
> --
> 2.19.1
>
--
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR
