On Wed, Mar 21, 2018 at 08:44:58AM +0200, Nikolay Borisov wrote:
>
>
> On 20.03.2018 21:25, jeffm@xxxxxxxx wrote:
> > From: Jeff Mahoney <jeffm@xxxxxxxx>
> >
> > Any time the first block group of a new type is created, we add a new
> > kobject to sysfs to hold the attributes for that type. Kobject-internal
> > allocations always use GFP_KERNEL, making them prone to fs-reclaim races.
> > While it appears as if this can occur any time a block group is created,
> > the only times the first block group of a new type can be created in
> > memory is at mount and when we create the first new block group during
> > raid conversion.
> >
> > This patch adds a new list to track pending kobject additions and then
> > handles them after we do chunk relocation. Between relocating the
> > target chunk (or forcing allocation of a new chunk in the case of data)
> > and removing the old chunk, we're in a safe place for fs-reclaim to
> > occur. We're holding the volume mutex, which is already held across
> > page faults, and the delete_unused_bgs_mutex, which will only stall
> > the cleaner thread.
> >
> > Signed-off-by: Jeff Mahoney <jeffm@xxxxxxxx>
> > ---
> > fs/btrfs/ctree.h | 6 ++++-
> > fs/btrfs/disk-io.c | 2 ++
> > fs/btrfs/extent-tree.c | 59 +++++++++++++++++++++++++++++++++++---------------
> > fs/btrfs/sysfs.c | 2 +-
> > fs/btrfs/volumes.c | 12 ++++++++++
> > 5 files changed, 61 insertions(+), 20 deletions(-)
> >
> > diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
> > index ffbb05aa66fa..75dbdf1bbead 100644
> > --- a/fs/btrfs/ctree.h
> > +++ b/fs/btrfs/ctree.h
> > @@ -381,8 +381,9 @@ struct btrfs_dev_replace {
> >
> > /* For raid type sysfs entries */
> > struct raid_kobject {
> > - int raid_type;
> > + u64 flags;
> > struct kobject kobj;
> > + struct list_head list;
> > };
> >
> > struct btrfs_space_info {
> > @@ -938,6 +939,8 @@ struct btrfs_fs_info {
> > int thread_pool_size;
> >
> > struct kobject *space_info_kobj;
> > + struct list_head pending_raid_kobjs;
> > + spinlock_t pending_raid_kobjs_lock; /* uncontended */
> >
> > u64 total_pinned;
> >
> > @@ -2688,6 +2691,7 @@ int btrfs_can_relocate(struct btrfs_fs_info *fs_info, u64 bytenr);
> > int btrfs_make_block_group(struct btrfs_trans_handle *trans,
> > struct btrfs_fs_info *fs_info, u64 bytes_used,
> > u64 type, u64 chunk_offset, u64 size);
> > +void btrfs_add_raid_kobjects(struct btrfs_fs_info *fs_info);
> > struct btrfs_trans_handle *btrfs_start_trans_remove_block_group(
> > struct btrfs_fs_info *fs_info,
> > const u64 chunk_offset);
> > diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
> > index eb6bb3169a9e..d5e1c2ff71ff 100644
> > --- a/fs/btrfs/disk-io.c
> > +++ b/fs/btrfs/disk-io.c
> > @@ -2447,6 +2447,8 @@ int open_ctree(struct super_block *sb,
> > INIT_LIST_HEAD(&fs_info->delayed_iputs);
> > INIT_LIST_HEAD(&fs_info->delalloc_roots);
> > INIT_LIST_HEAD(&fs_info->caching_block_groups);
> > + INIT_LIST_HEAD(&fs_info->pending_raid_kobjs);
> > + spin_lock_init(&fs_info->pending_raid_kobjs_lock);
> > spin_lock_init(&fs_info->delalloc_root_lock);
> > spin_lock_init(&fs_info->trans_lock);
> > spin_lock_init(&fs_info->fs_roots_radix_lock);
> > diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
> > index 0e9a21230217..bb5368faa937 100644
> > --- a/fs/btrfs/extent-tree.c
> > +++ b/fs/btrfs/extent-tree.c
> > @@ -9908,9 +9908,39 @@ int btrfs_free_block_groups(struct btrfs_fs_info *info)
> > return 0;
> > }
> >
> > +/* link_block_group will queue up kobjects to add when we're reclaim-safe */
> > +void btrfs_add_raid_kobjects(struct btrfs_fs_info *fs_info)
> > +{
> > + struct btrfs_space_info *space_info;
> > + struct raid_kobject *rkobj;
> > + LIST_HEAD(list);
> > + int index;
> > + int ret = 0;
> > +
> > + spin_lock(&fs_info->pending_raid_kobjs_lock);
> > + list_splice_init(&fs_info->pending_raid_kobjs, &list);
> > + spin_unlock(&fs_info->pending_raid_kobjs_lock);
> > +
> > + list_for_each_entry(rkobj, &list, list) {
> > + space_info = __find_space_info(fs_info, rkobj->flags);
> > + index = __get_raid_index(rkobj->flags);
>
> This function is no more. It was refactored in 24bc2843edd5 ("btrfs:
> Refactor __get_raid_index() to btrfs_bg_flags_to_raid_index()")
>
>
> So I guess you should use btrfs_bg_flags_to_raid_index instead.
Fixed and patches added to next, thanks.
--
To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
