On 10/26/2018 07:43 PM, Nikolay Borisov wrote:
btrfs_can_relocate returns 0 when it concludes the given chunk can be relocated and -1 otherwise. Since this function is used as a predicated and it return a binary value it makes no sense to have it's return value as an int so change it to bool. Furthermore, remove a stale leftover comment from e6ec716f0ddb ("Btrfs: make raid attr array more readable"). Finally make the logic in the list_for_each_entry loop a bit more obvious. Up until now the fact that we are returning success (0) was a bit masked by the fact that the 0 is re-used from the return value of find_free_dev_extent. Instead, now just increment dev_nr if we find a suitable extent and explicitly set can_reloc to true if enough devices with unallocated space are present. No functional changes. Signed-off-by: Nikolay Borisov <nbori...@suse.com> --- fs/btrfs/ctree.h | 2 +- fs/btrfs/extent-tree.c | 39 ++++++++++++++------------------------- fs/btrfs/volumes.c | 3 +-- 3 files changed, 16 insertions(+), 28 deletions(-) diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h index 68ca41dbbef3..06edc4f9ceb2 100644 --- a/fs/btrfs/ctree.h +++ b/fs/btrfs/ctree.h @@ -2680,7 +2680,7 @@ int btrfs_setup_space_cache(struct btrfs_trans_handle *trans, int btrfs_extent_readonly(struct btrfs_fs_info *fs_info, u64 bytenr); int btrfs_free_block_groups(struct btrfs_fs_info *info); int btrfs_read_block_groups(struct btrfs_fs_info *info); -int btrfs_can_relocate(struct btrfs_fs_info *fs_info, u64 bytenr); +bool btrfs_can_relocate(struct btrfs_fs_info *fs_info, u64 bytenr); int btrfs_make_block_group(struct btrfs_trans_handle *trans, u64 bytes_used, u64 type, u64 chunk_offset, u64 size); diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c index a1febf155747..816bca482358 100644 --- a/fs/btrfs/extent-tree.c +++ b/fs/btrfs/extent-tree.c @@ -9423,10 +9423,10 @@ void btrfs_dec_block_group_ro(struct btrfs_block_group_cache *cache) /* * checks to see if its even possible to relocate this block group. * - * @return - -1 if it's not a good idea to relocate this block group, 0 if its - * ok to go ahead and try. + * @return - false if not enough space can be found for relocation, true + * otherwise */ -int btrfs_can_relocate(struct btrfs_fs_info *fs_info, u64 bytenr) +bool btrfs_can_relocate(struct btrfs_fs_info *fs_info, u64 bytenr) { struct btrfs_root *root = fs_info->extent_root; struct btrfs_block_group_cache *block_group; @@ -9441,7 +9441,7 @@ int btrfs_can_relocate(struct btrfs_fs_info *fs_info, u64 bytenr) int debug; int index; int full = 0; - int ret = 0; + bool can_reloc = true;debug = btrfs_test_opt(fs_info, ENOSPC_DEBUG); @@ -9453,7 +9453,7 @@ int btrfs_can_relocate(struct btrfs_fs_info *fs_info, u64 bytenr)btrfs_warn(fs_info, "can't find block group for bytenr %llu", bytenr); - return -1; + return false; }min_free = btrfs_block_group_used(&block_group->item);@@ -9489,16 +9489,8 @@ int btrfs_can_relocate(struct btrfs_fs_info *fs_info, u64 bytenr) * group is going to be restriped, run checks against the target * profile instead of the current one. */ - ret = -1; + can_reloc = false;- /*- * index: - * 0: raid10 - * 1: raid1 - * 2: dup - * 3: raid0 - * 4: single - */ target = get_restripe_target(fs_info, block_group->flags); if (target) { index = btrfs_bg_flags_to_raid_index(extended_to_chunk(target)); @@ -9534,10 +9526,8 @@ int btrfs_can_relocate(struct btrfs_fs_info *fs_info, u64 bytenr)/* We need to do this so that we can look at pending chunks */trans = btrfs_join_transaction(root); - if (IS_ERR(trans)) { - ret = PTR_ERR(trans); + if (IS_ERR(trans)) goto out; - }mutex_lock(&fs_info->chunk_mutex);list_for_each_entry(device, &fs_devices->alloc_list, dev_alloc_list) { @@ -9549,18 +9539,17 @@ int btrfs_can_relocate(struct btrfs_fs_info *fs_info, u64 bytenr) */ if (device->total_bytes > device->bytes_used + min_free && !test_bit(BTRFS_DEV_STATE_REPLACE_TGT, &device->dev_state)) { - ret = find_free_dev_extent(trans, device, min_free, - &dev_offset, NULL); - if (!ret) + if (!find_free_dev_extent(trans, device, min_free, + &dev_offset, NULL))
This can return -ENOMEM;
dev_nr++;- if (dev_nr >= dev_min)+ if (dev_nr >= dev_min) { + can_reloc = true; break; - - ret = -1; + } } } - if (debug && ret == -1) + if (debug && !can_reloc) btrfs_warn(fs_info, "no space to allocate a new chunk for block group %llu", block_group->key.objectid); @@ -9568,7 +9557,7 @@ int btrfs_can_relocate(struct btrfs_fs_info *fs_info, u64 bytenr) btrfs_end_transaction(trans); out: btrfs_put_block_group(block_group); - return ret; + return can_reloc; }static int find_first_block_group(struct btrfs_fs_info *fs_info,diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index 8b0fd7bf3447..dc53d94a62aa 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -2856,8 +2856,7 @@ static int btrfs_relocate_chunk(struct btrfs_fs_info *fs_info, u64 chunk_offset) */ lockdep_assert_held(&fs_info->delete_unused_bgs_mutex);- ret = btrfs_can_relocate(fs_info, chunk_offset);- if (ret) + if (!btrfs_can_relocate(fs_info, chunk_offset)) return -ENOSPC;
And ends up converting -ENOMEM to -ENOSPC. Its better to propagate the accurate error. Thanks, Anand
/* step one, relocate all the extents inside this chunk */
