On Tue, Dec 17, 2019 at 04:32:04PM -0500, Josef Bacik wrote:
On 12/12/19 11:09 PM, Naohiro Aota wrote:To serialize allocation and submit_bio, we introduced mutex around them. As a result, preallocation must be completely disabled to avoid a deadlock. Since current relocation process relies on preallocation to move file data extents, it must be handled in another way. In HMZONED mode, we just truncate the inode to the size that we wanted to pre-allocate. Then, we flush dirty pages on the file before finishing relocation process. run_delalloc_hmzoned() will handle all the allocation and submit IOs to the underlying layers. Signed-off-by: Naohiro Aota <naohiro.aota@xxxxxxx> --- fs/btrfs/relocation.c | 39 +++++++++++++++++++++++++++++++++++++-- 1 file changed, 37 insertions(+), 2 deletions(-) diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c index d897a8e5e430..2d17b7566df4 100644 --- a/fs/btrfs/relocation.c +++ b/fs/btrfs/relocation.c @@ -3159,6 +3159,34 @@ int prealloc_file_extent_cluster(struct inode *inode, if (ret) goto out; + /* + * In HMZONED, we cannot preallocate the file region. Instead, + * we dirty and fiemap_write the region. + */ + + if (btrfs_fs_incompat(btrfs_sb(inode->i_sb), HMZONED)) { + struct btrfs_root *root = BTRFS_I(inode)->root; + struct btrfs_trans_handle *trans; + + end = cluster->end - offset + 1; + trans = btrfs_start_transaction(root, 1); + if (IS_ERR(trans)) + return PTR_ERR(trans); + + inode->i_ctime = current_time(inode); + i_size_write(inode, end); + btrfs_ordered_update_i_size(inode, end, NULL); + ret = btrfs_update_inode(trans, root, inode); + if (ret) { + btrfs_abort_transaction(trans, ret); + btrfs_end_transaction(trans); + return ret; + } + ret = btrfs_end_transaction(trans); + + goto out; + } +Why are we arbitrarily extending the i_size here? If we don't need prealloc we don't need to jack up the i_size either.
We need to extend i_size to read data from the relocating block group. If not, btrfs_readpage() in relocate_file_extent_cluster() always reads zero filled page because the read position is beyond the file size.
cur_offset = prealloc_start; while (nr < cluster->nr) { start = cluster->boundary[nr] - offset; @@ -3346,6 +3374,10 @@ static int relocate_file_extent_cluster(struct inode *inode, btrfs_throttle(fs_info); } WARN_ON(nr != cluster->nr); + if (btrfs_fs_incompat(fs_info, HMZONED) && !ret) { + ret = btrfs_wait_ordered_range(inode, 0, (u64)-1); + WARN_ON(ret);Do not WAR_ON() when this could happen due to IO errors. Thanks, Josef
Sure. We can just drop it.
