| Message ID | 20180830174225.2200-23-josef@toxicpanda.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | My current patch queue | expand |
On 30.08.2018 20:42, Josef Bacik wrote: > We can actually allocate new chunks while we're creating our bg's, so > instead of doing list_for_each_safe, just do while (!list_empty()) so we > make sure to catch any new bg's that get added to the list. HOw can this occur, please elaborate and put an example callstack in the commit log. > > Signed-off-by: Josef Bacik <josef@toxicpanda.com> > --- > fs/btrfs/extent-tree.c | 7 +++++-- > 1 file changed, 5 insertions(+), 2 deletions(-) > > diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c > index ca98c39308f6..fc30ff96f0d6 100644 > --- a/fs/btrfs/extent-tree.c > +++ b/fs/btrfs/extent-tree.c > @@ -10331,7 +10331,7 @@ int btrfs_read_block_groups(struct btrfs_fs_info *info) > void btrfs_create_pending_block_groups(struct btrfs_trans_handle *trans) > { > struct btrfs_fs_info *fs_info = trans->fs_info; > - struct btrfs_block_group_cache *block_group, *tmp; > + struct btrfs_block_group_cache *block_group; > struct btrfs_root *extent_root = fs_info->extent_root; > struct btrfs_block_group_item item; > struct btrfs_key key; > @@ -10339,7 +10339,10 @@ void btrfs_create_pending_block_groups(struct btrfs_trans_handle *trans) > bool can_flush_pending_bgs = trans->can_flush_pending_bgs; > > trans->can_flush_pending_bgs = false; > - list_for_each_entry_safe(block_group, tmp, &trans->new_bgs, bg_list) { > + while (!list_empty(&trans->new_bgs)) { > + block_group = list_first_entry(&trans->new_bgs, > + struct btrfs_block_group_cache, > + bg_list); > if (ret) > goto next; > >
On Fri, Aug 31, 2018 at 10:31:49AM +0300, Nikolay Borisov wrote: > > > On 30.08.2018 20:42, Josef Bacik wrote: > > We can actually allocate new chunks while we're creating our bg's, so > > instead of doing list_for_each_safe, just do while (!list_empty()) so we > > make sure to catch any new bg's that get added to the list. > > HOw can this occur, please elaborate and put an example callstack in the > commit log. > Eh? We're modifying the extent tree and chunk tree, which can cause bg's to be allocated, it's just common sense. Josef
On Thu, Aug 30, 2018 at 01:42:12PM -0400, Josef Bacik wrote: > We can actually allocate new chunks while we're creating our bg's, so > instead of doing list_for_each_safe, just do while (!list_empty()) so we > make sure to catch any new bg's that get added to the list. Reviewed-by: Omar Sandoval <osandov@fb.com> Since Nikolay pointed it out, might as well mention in the commit message that this can happen because we modify the chunk and extent trees. > Signed-off-by: Josef Bacik <josef@toxicpanda.com> > --- > fs/btrfs/extent-tree.c | 7 +++++-- > 1 file changed, 5 insertions(+), 2 deletions(-) > > diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c > index ca98c39308f6..fc30ff96f0d6 100644 > --- a/fs/btrfs/extent-tree.c > +++ b/fs/btrfs/extent-tree.c > @@ -10331,7 +10331,7 @@ int btrfs_read_block_groups(struct btrfs_fs_info *info) > void btrfs_create_pending_block_groups(struct btrfs_trans_handle *trans) > { > struct btrfs_fs_info *fs_info = trans->fs_info; > - struct btrfs_block_group_cache *block_group, *tmp; > + struct btrfs_block_group_cache *block_group; > struct btrfs_root *extent_root = fs_info->extent_root; > struct btrfs_block_group_item item; > struct btrfs_key key; > @@ -10339,7 +10339,10 @@ void btrfs_create_pending_block_groups(struct btrfs_trans_handle *trans) > bool can_flush_pending_bgs = trans->can_flush_pending_bgs; > > trans->can_flush_pending_bgs = false; > - list_for_each_entry_safe(block_group, tmp, &trans->new_bgs, bg_list) { > + while (!list_empty(&trans->new_bgs)) { > + block_group = list_first_entry(&trans->new_bgs, > + struct btrfs_block_group_cache, > + bg_list); > if (ret) > goto next; > > -- > 2.14.3 >
On Fri, Aug 31, 2018 at 7:03 AM, Josef Bacik <josef@toxicpanda.com> wrote: > On Fri, Aug 31, 2018 at 10:31:49AM +0300, Nikolay Borisov wrote: >> >> >> On 30.08.2018 20:42, Josef Bacik wrote: >> > We can actually allocate new chunks while we're creating our bg's, so >> > instead of doing list_for_each_safe, just do while (!list_empty()) so we >> > make sure to catch any new bg's that get added to the list. >> >> HOw can this occur, please elaborate and put an example callstack in the >> commit log. >> > > Eh? We're modifying the extent tree and chunk tree, which can cause bg's to be > allocated, it's just common sense. > This explains a bit. => btrfs_make_block_group => __btrfs_alloc_chunk => do_chunk_alloc => find_free_extent => btrfs_reserve_extent => btrfs_alloc_tree_block => __btrfs_cow_block => btrfs_cow_block => btrfs_search_slot => btrfs_update_device => btrfs_finish_chunk_alloc => btrfs_create_pending_block_groups ... Reviewed-by: Liu Bo <bo.liu@linux.alibaba.com> thanks, liubo
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c index ca98c39308f6..fc30ff96f0d6 100644 --- a/fs/btrfs/extent-tree.c +++ b/fs/btrfs/extent-tree.c @@ -10331,7 +10331,7 @@ int btrfs_read_block_groups(struct btrfs_fs_info *info) void btrfs_create_pending_block_groups(struct btrfs_trans_handle *trans) { struct btrfs_fs_info *fs_info = trans->fs_info; - struct btrfs_block_group_cache *block_group, *tmp; + struct btrfs_block_group_cache *block_group; struct btrfs_root *extent_root = fs_info->extent_root; struct btrfs_block_group_item item; struct btrfs_key key; @@ -10339,7 +10339,10 @@ void btrfs_create_pending_block_groups(struct btrfs_trans_handle *trans) bool can_flush_pending_bgs = trans->can_flush_pending_bgs; trans->can_flush_pending_bgs = false; - list_for_each_entry_safe(block_group, tmp, &trans->new_bgs, bg_list) { + while (!list_empty(&trans->new_bgs)) { + block_group = list_first_entry(&trans->new_bgs, + struct btrfs_block_group_cache, + bg_list); if (ret) goto next;
We can actually allocate new chunks while we're creating our bg's, so instead of doing list_for_each_safe, just do while (!list_empty()) so we make sure to catch any new bg's that get added to the list. Signed-off-by: Josef Bacik <josef@toxicpanda.com> --- fs/btrfs/extent-tree.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-)