| Message ID | 1540554201-11305-3-git-send-email-nborisov@suse.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Misc cleanups in balance code | expand |
On 2018/10/26 下午7:43, 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 <nborisov@suse.com> Reviewed-by: Qu Wenruo <wqu@suse.com> Thanks, Qu > --- > 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)) > 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; > > /* step one, relocate all the extents inside this chunk */ >
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 <nborisov@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 */ >
On Sat, Nov 17, 2018 at 09:29:27AM +0800, Anand Jain wrote: > > - 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; > > > @@ -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. Right, converting to bool is obscuring the reason why the functions fail. Making the code simpler at this cost does not look like a good idea to me. I'll remove the patch from misc-next for now.
On 3.12.18 г. 19:25 ч., David Sterba wrote: > On Sat, Nov 17, 2018 at 09:29:27AM +0800, Anand Jain wrote: >>> - 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; >> >>> @@ -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. > > Right, converting to bool is obscuring the reason why the functions > fail. Making the code simpler at this cost does not look like a good > idea to me. I'll remove the patch from misc-next for now. The patch itself does not make the code more obscure than currently is, because even if ENOMEM is returned it's still converted to ENOSPC in btrfs_relocate_chunk. >
On Tue, Dec 04, 2018 at 08:34:15AM +0200, Nikolay Borisov wrote: > > > On 3.12.18 г. 19:25 ч., David Sterba wrote: > > On Sat, Nov 17, 2018 at 09:29:27AM +0800, Anand Jain wrote: > >>> - 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; > >> > >>> @@ -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. > > > > Right, converting to bool is obscuring the reason why the functions > > fail. Making the code simpler at this cost does not look like a good > > idea to me. I'll remove the patch from misc-next for now. > > The patch itself does not make the code more obscure than currently is, > because even if ENOMEM is returned it's still converted to ENOSPC in > btrfs_relocate_chunk. Sorry, but this can be hardly used as an excuse to keep the code obscure. btrfs_can_relocate & co are not very often changed so there's cruft accumulated. The error value propagation was probably not a hot topic in 2009, btrfs_can_relocate needs the cleanups but please let's do that properly.
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)) 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; /* step one, relocate all the extents inside this chunk */
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 <nborisov@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(-)