On Fri, Aug 02, 2019 at 05:00:40PM -0500, Goldwyn Rodrigues wrote:
> From: Goldwyn Rodrigues <rgoldwyn@xxxxxxxx>
>
> Set iomap->type to IOMAP_COW and fill up the source map in case
> the I/O is not page aligned.
.....
> static void btrfs_buffered_page_done(struct inode *inode, loff_t pos,
> unsigned copied, struct page *page,
> struct iomap *iomap)
> @@ -188,6 +217,7 @@ static int btrfs_buffered_iomap_begin(struct inode *inode, loff_t pos,
> int ret;
> size_t write_bytes = length;
> struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
> + size_t end;
> size_t sector_offset = pos & (fs_info->sectorsize - 1);
> struct btrfs_iomap *bi;
>
> @@ -255,6 +285,17 @@ static int btrfs_buffered_iomap_begin(struct inode *inode, loff_t pos,
> iomap->private = bi;
> iomap->length = round_up(write_bytes, fs_info->sectorsize);
> iomap->offset = round_down(pos, fs_info->sectorsize);
> + end = pos + write_bytes;
> + /* Set IOMAP_COW if start/end is not page aligned */
> + if (((pos & (PAGE_SIZE - 1)) || (end & (PAGE_SIZE - 1)))) {
> + iomap->type = IOMAP_COW;
> + ret = get_iomap(inode, pos, length, srcmap);
> + if (ret < 0)
> + goto release;
I suspect you didn't test this case, because....
> + } else {
> + iomap->type = IOMAP_DELALLOC;
> + }
> +
> iomap->addr = IOMAP_NULL_ADDR;
> iomap->type = IOMAP_DELALLOC;
The iomap->type is overwritten here and so IOMAP_COW will never be
seen by the iomap infrastructure...
Cheers,
Dave.
--
Dave Chinner
david@xxxxxxxxxxxxx
