| Message ID | e19ba3fe887ce6ace42c8d57cf0db54e38ab5eb3.1604591048.git.josef@toxicpanda.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Set the lockdep class on eb's at allocation time | expand |
On Thu, Nov 5, 2020 at 3:47 PM Josef Bacik <josef@toxicpanda.com> wrote: > > We have this weird problem where our lockdep class is set after we > read a tree block, which can race with concurrent readers and result in > erroneous lockdep errors. We want to set the lockdep class at > allocation time if possible, but in certain cases we may not have the > actual root owner, such as with relocation or any backref lookups. This > is only really a problem for reference counted tree's, because all other > tree's have their root reference set in their extent reference. Remove > the fs tree specific lock class. We need to still keep the reloc tree > one, it's still reference counted, because replace_path will lock the > reloc tree and the destination tree, and if they're both set to > tree-<level> we'll have issues. > > Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: Filipe Manana <fdmanana@suse.com> I couldn't get anymore the lockdep splat I reported before, it used to happen very often with btrfs/033. Looks good, thanks. > --- > fs/btrfs/disk-io.c | 1 - > 1 file changed, 1 deletion(-) > > diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c > index 212806d59012..35b16fe3b05f 100644 > --- a/fs/btrfs/disk-io.c > +++ b/fs/btrfs/disk-io.c > @@ -173,7 +173,6 @@ static struct btrfs_lockdep_keyset { > { .id = BTRFS_EXTENT_TREE_OBJECTID, DEFINE_NAME("extent") }, > { .id = BTRFS_CHUNK_TREE_OBJECTID, DEFINE_NAME("chunk") }, > { .id = BTRFS_DEV_TREE_OBJECTID, DEFINE_NAME("dev") }, > - { .id = BTRFS_FS_TREE_OBJECTID, DEFINE_NAME("fs") }, > { .id = BTRFS_CSUM_TREE_OBJECTID, DEFINE_NAME("csum") }, > { .id = BTRFS_QUOTA_TREE_OBJECTID, DEFINE_NAME("quota") }, > { .id = BTRFS_TREE_LOG_OBJECTID, DEFINE_NAME("log") }, > -- > 2.26.2 >
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c index 212806d59012..35b16fe3b05f 100644 --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -173,7 +173,6 @@ static struct btrfs_lockdep_keyset { { .id = BTRFS_EXTENT_TREE_OBJECTID, DEFINE_NAME("extent") }, { .id = BTRFS_CHUNK_TREE_OBJECTID, DEFINE_NAME("chunk") }, { .id = BTRFS_DEV_TREE_OBJECTID, DEFINE_NAME("dev") }, - { .id = BTRFS_FS_TREE_OBJECTID, DEFINE_NAME("fs") }, { .id = BTRFS_CSUM_TREE_OBJECTID, DEFINE_NAME("csum") }, { .id = BTRFS_QUOTA_TREE_OBJECTID, DEFINE_NAME("quota") }, { .id = BTRFS_TREE_LOG_OBJECTID, DEFINE_NAME("log") },
We have this weird problem where our lockdep class is set after we read a tree block, which can race with concurrent readers and result in erroneous lockdep errors. We want to set the lockdep class at allocation time if possible, but in certain cases we may not have the actual root owner, such as with relocation or any backref lookups. This is only really a problem for reference counted tree's, because all other tree's have their root reference set in their extent reference. Remove the fs tree specific lock class. We need to still keep the reloc tree one, it's still reference counted, because replace_path will lock the reloc tree and the destination tree, and if they're both set to tree-<level> we'll have issues. Signed-off-by: Josef Bacik <josef@toxicpanda.com> --- fs/btrfs/disk-io.c | 1 - 1 file changed, 1 deletion(-)