On Thu 15-07-21 09:54:49, Zhang Yi wrote:
> After commit 3da40c7b0898 ("ext4: only call ext4_truncate when size <=
> isize"), i_disksize could always be updated to i_size in ext4_setattr(),
> and we could sure that i_disksize <= i_size since holding inode lock and
> if i_disksize < i_size there are delalloc writes pending in the range
> upto i_size. If the end of the current write is <= i_size, there's no
> need to touch i_disksize since writeback will push i_disksize upto
> i_size eventually. So we can switch to check i_size instead of
> i_disksize in ext4_da_write_end() when write to the end of the file.
> we also could remove ext4_mark_inode_dirty() together because we defer
> inode dirtying to generic_write_end() or ext4_da_write_inline_data_end().
>
> Signed-off-by: Zhang Yi <yi.zhang@xxxxxxxxxx>
Looks good. Feel free to add:
Reviewed-by: Jan Kara <jack@xxxxxxx>
Honza
> ---
> fs/ext4/inode.c | 34 ++++++++++++++++++----------------
> 1 file changed, 18 insertions(+), 16 deletions(-)
>
> diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
> index d8de607849df..dca8e3810443 100644
> --- a/fs/ext4/inode.c
> +++ b/fs/ext4/inode.c
> @@ -3084,35 +3084,37 @@ static int ext4_da_write_end(struct file *file,
> end = start + copied - 1;
>
> /*
> - * generic_write_end() will run mark_inode_dirty() if i_size
> - * changes. So let's piggyback the i_disksize mark_inode_dirty
> - * into that.
> + * Since we are holding inode lock, we are sure i_disksize <=
> + * i_size. We also know that if i_disksize < i_size, there are
> + * delalloc writes pending in the range upto i_size. If the end of
> + * the current write is <= i_size, there's no need to touch
> + * i_disksize since writeback will push i_disksize upto i_size
> + * eventually. If the end of the current write is > i_size and
> + * inside an allocated block (ext4_da_should_update_i_disksize()
> + * check), we need to update i_disksize here as neither
> + * ext4_writepage() nor certain ext4_writepages() paths not
> + * allocating blocks update i_disksize.
> + *
> + * Note that we defer inode dirtying to generic_write_end() /
> + * ext4_da_write_inline_data_end().
> */
> new_i_size = pos + copied;
> - if (copied && new_i_size > EXT4_I(inode)->i_disksize) {
> + if (copied && new_i_size > inode->i_size) {
> if (ext4_has_inline_data(inode) ||
> - ext4_da_should_update_i_disksize(page, end)) {
> + ext4_da_should_update_i_disksize(page, end))
> ext4_update_i_disksize(inode, new_i_size);
> - /* We need to mark inode dirty even if
> - * new_i_size is less that inode->i_size
> - * bu greater than i_disksize.(hint delalloc)
> - */
> - ret = ext4_mark_inode_dirty(handle, inode);
> - }
> }
>
> if (write_mode != CONVERT_INLINE_DATA &&
> ext4_test_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA) &&
> ext4_has_inline_data(inode))
> - ret2 = ext4_da_write_inline_data_end(inode, pos, len, copied,
> + ret = ext4_da_write_inline_data_end(inode, pos, len, copied,
> page);
> else
> - ret2 = generic_write_end(file, mapping, pos, len, copied,
> + ret = generic_write_end(file, mapping, pos, len, copied,
> page, fsdata);
>
> - copied = ret2;
> - if (ret2 < 0)
> - ret = ret2;
> + copied = ret;
> ret2 = ext4_journal_stop(handle);
> if (unlikely(ret2 && !ret))
> ret = ret2;
> --
> 2.31.1
>
--
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR
