Jan Schmidt
2013-Mar-20 13:49 UTC
[PATCH v2] Btrfs: fix locking on ROOT_REPLACE operations in tree mod log
To resolve backrefs, ROOT_REPLACE operations in the tree mod log are
required to be tied to at least one KEY_REMOVE_WHILE_FREEING operation.
Therefore, those operations must be enclosed by tree_mod_log_write_lock()
and tree_mod_log_write_unlock() calls.
Those calls are private to the tree_mod_log_* functions, which means that
removal of the elements of an old root node must be logged from
tree_mod_log_insert_root. This partly reverts and corrects commit ba1bfbd5
(Btrfs: fix a tree mod logging issue for root replacement operations).
This fixes the brand-new version of xfstest 276 as of commit cfe73f71.
Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net>
---
Has probably been Reported-by: Alex Lyakas <alex.btrfs@zadarastorage.com>
(unconfirmed).
Chages for v2:
- use the correct base (current cmason/for-linus)
fs/btrfs/ctree.c | 30 ++++++++++++++++++++----------
1 files changed, 20 insertions(+), 10 deletions(-)
diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index ecd25a1..ca9d8f1 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -651,6 +651,8 @@ tree_mod_log_insert_root(struct btrfs_fs_info *fs_info,
if (tree_mod_dont_log(fs_info, NULL))
return 0;
+ __tree_mod_log_free_eb(fs_info, old_root);
+
ret = tree_mod_alloc(fs_info, flags, &tm);
if (ret < 0)
goto out;
@@ -736,7 +738,7 @@ tree_mod_log_search(struct btrfs_fs_info *fs_info, u64
start, u64 min_seq)
static noinline void
tree_mod_log_eb_copy(struct btrfs_fs_info *fs_info, struct extent_buffer *dst,
struct extent_buffer *src, unsigned long dst_offset,
- unsigned long src_offset, int nr_items)
+ unsigned long src_offset, int nr_items, int log_removal)
{
int ret;
int i;
@@ -750,10 +752,12 @@ tree_mod_log_eb_copy(struct btrfs_fs_info *fs_info, struct
extent_buffer *dst,
}
for (i = 0; i < nr_items; i++) {
- ret = tree_mod_log_insert_key_locked(fs_info, src,
- i + src_offset,
- MOD_LOG_KEY_REMOVE);
- BUG_ON(ret < 0);
+ if (log_removal) {
+ ret = tree_mod_log_insert_key_locked(fs_info, src,
+ i + src_offset,
+ MOD_LOG_KEY_REMOVE);
+ BUG_ON(ret < 0);
+ }
ret = tree_mod_log_insert_key_locked(fs_info, dst,
i + dst_offset,
MOD_LOG_KEY_ADD);
@@ -927,7 +931,6 @@ static noinline int update_ref_for_cow(struct
btrfs_trans_handle *trans,
ret = btrfs_dec_ref(trans, root, buf, 1, 1);
BUG_ON(ret); /* -ENOMEM */
}
- tree_mod_log_free_eb(root->fs_info, buf);
clean_tree_block(trans, root, buf);
*last_ref = 1;
}
@@ -1046,6 +1049,7 @@ static noinline int __btrfs_cow_block(struct
btrfs_trans_handle *trans,
btrfs_set_node_ptr_generation(parent, parent_slot,
trans->transid);
btrfs_mark_buffer_dirty(parent);
+ tree_mod_log_free_eb(root->fs_info, buf);
btrfs_free_tree_block(trans, root, buf, parent_start,
last_ref);
}
@@ -1750,7 +1754,6 @@ static noinline int balance_level(struct
btrfs_trans_handle *trans,
goto enospc;
}
- tree_mod_log_free_eb(root->fs_info, root->node);
tree_mod_log_set_root_pointer(root, child);
rcu_assign_pointer(root->node, child);
@@ -2995,7 +2998,7 @@ static int push_node_left(struct btrfs_trans_handle
*trans,
push_items = min(src_nritems - 8, push_items);
tree_mod_log_eb_copy(root->fs_info, dst, src, dst_nritems, 0,
- push_items);
+ push_items, 1);
copy_extent_buffer(dst, src,
btrfs_node_key_ptr_offset(dst_nritems),
btrfs_node_key_ptr_offset(0),
@@ -3066,7 +3069,7 @@ static int balance_node_right(struct btrfs_trans_handle
*trans,
sizeof(struct btrfs_key_ptr));
tree_mod_log_eb_copy(root->fs_info, dst, src, 0,
- src_nritems - push_items, push_items);
+ src_nritems - push_items, push_items, 1);
copy_extent_buffer(dst, src,
btrfs_node_key_ptr_offset(0),
btrfs_node_key_ptr_offset(src_nritems - push_items),
@@ -3218,12 +3221,18 @@ static noinline int split_node(struct btrfs_trans_handle
*trans,
int mid;
int ret;
u32 c_nritems;
+ int tree_mod_log_removal = 1;
c = path->nodes[level];
WARN_ON(btrfs_header_generation(c) != trans->transid);
if (c == root->node) {
/* trying to split the root, lets make a new one */
ret = insert_new_root(trans, root, path, level + 1);
+ /*
+ * removal of root nodes has been logged by
+ * tree_mod_log_set_root_pointer due to locking
+ */
+ tree_mod_log_removal = 0;
if (ret)
return ret;
} else {
@@ -3261,7 +3270,8 @@ static noinline int split_node(struct btrfs_trans_handle
*trans,
(unsigned long)btrfs_header_chunk_tree_uuid(split),
BTRFS_UUID_SIZE);
- tree_mod_log_eb_copy(root->fs_info, split, c, 0, mid, c_nritems - mid);
+ tree_mod_log_eb_copy(root->fs_info, split, c, 0, mid, c_nritems - mid,
+ tree_mod_log_removal);
copy_extent_buffer(split, c,
btrfs_node_key_ptr_offset(0),
btrfs_node_key_ptr_offset(mid),
--
1.7.1
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Alex Lyakas
2013-Apr-02 19:13 UTC
Re: [PATCH v2] Btrfs: fix locking on ROOT_REPLACE operations in tree mod log
Hi Jan, I have manually applied this patch and also your previous patch onto kernel 3.8.2, but, unfortunately, I am still hitting the issue:( I will check further whether I can be more helpful in debugging this issue, than just reporting it:( Thank for your help, Alex. On Wed, Mar 20, 2013 at 3:49 PM, Jan Schmidt <list.btrfs@jan-o-sch.net> wrote:> To resolve backrefs, ROOT_REPLACE operations in the tree mod log are > required to be tied to at least one KEY_REMOVE_WHILE_FREEING operation. > Therefore, those operations must be enclosed by tree_mod_log_write_lock() > and tree_mod_log_write_unlock() calls. > > Those calls are private to the tree_mod_log_* functions, which means that > removal of the elements of an old root node must be logged from > tree_mod_log_insert_root. This partly reverts and corrects commit ba1bfbd5 > (Btrfs: fix a tree mod logging issue for root replacement operations). > > This fixes the brand-new version of xfstest 276 as of commit cfe73f71. > > Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net> > --- > Has probably been Reported-by: Alex Lyakas <alex.btrfs@zadarastorage.com> > (unconfirmed). > > Chages for v2: > - use the correct base (current cmason/for-linus) > > fs/btrfs/ctree.c | 30 ++++++++++++++++++++---------- > 1 files changed, 20 insertions(+), 10 deletions(-) > > diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c > index ecd25a1..ca9d8f1 100644 > --- a/fs/btrfs/ctree.c > +++ b/fs/btrfs/ctree.c > @@ -651,6 +651,8 @@ tree_mod_log_insert_root(struct btrfs_fs_info *fs_info, > if (tree_mod_dont_log(fs_info, NULL)) > return 0; > > + __tree_mod_log_free_eb(fs_info, old_root); > + > ret = tree_mod_alloc(fs_info, flags, &tm); > if (ret < 0) > goto out; > @@ -736,7 +738,7 @@ tree_mod_log_search(struct btrfs_fs_info *fs_info, u64 start, u64 min_seq) > static noinline void > tree_mod_log_eb_copy(struct btrfs_fs_info *fs_info, struct extent_buffer *dst, > struct extent_buffer *src, unsigned long dst_offset, > - unsigned long src_offset, int nr_items) > + unsigned long src_offset, int nr_items, int log_removal) > { > int ret; > int i; > @@ -750,10 +752,12 @@ tree_mod_log_eb_copy(struct btrfs_fs_info *fs_info, struct extent_buffer *dst, > } > > for (i = 0; i < nr_items; i++) { > - ret = tree_mod_log_insert_key_locked(fs_info, src, > - i + src_offset, > - MOD_LOG_KEY_REMOVE); > - BUG_ON(ret < 0); > + if (log_removal) { > + ret = tree_mod_log_insert_key_locked(fs_info, src, > + i + src_offset, > + MOD_LOG_KEY_REMOVE); > + BUG_ON(ret < 0); > + } > ret = tree_mod_log_insert_key_locked(fs_info, dst, > i + dst_offset, > MOD_LOG_KEY_ADD); > @@ -927,7 +931,6 @@ static noinline int update_ref_for_cow(struct btrfs_trans_handle *trans, > ret = btrfs_dec_ref(trans, root, buf, 1, 1); > BUG_ON(ret); /* -ENOMEM */ > } > - tree_mod_log_free_eb(root->fs_info, buf); > clean_tree_block(trans, root, buf); > *last_ref = 1; > } > @@ -1046,6 +1049,7 @@ static noinline int __btrfs_cow_block(struct btrfs_trans_handle *trans, > btrfs_set_node_ptr_generation(parent, parent_slot, > trans->transid); > btrfs_mark_buffer_dirty(parent); > + tree_mod_log_free_eb(root->fs_info, buf); > btrfs_free_tree_block(trans, root, buf, parent_start, > last_ref); > } > @@ -1750,7 +1754,6 @@ static noinline int balance_level(struct btrfs_trans_handle *trans, > goto enospc; > } > > - tree_mod_log_free_eb(root->fs_info, root->node); > tree_mod_log_set_root_pointer(root, child); > rcu_assign_pointer(root->node, child); > > @@ -2995,7 +2998,7 @@ static int push_node_left(struct btrfs_trans_handle *trans, > push_items = min(src_nritems - 8, push_items); > > tree_mod_log_eb_copy(root->fs_info, dst, src, dst_nritems, 0, > - push_items); > + push_items, 1); > copy_extent_buffer(dst, src, > btrfs_node_key_ptr_offset(dst_nritems), > btrfs_node_key_ptr_offset(0), > @@ -3066,7 +3069,7 @@ static int balance_node_right(struct btrfs_trans_handle *trans, > sizeof(struct btrfs_key_ptr)); > > tree_mod_log_eb_copy(root->fs_info, dst, src, 0, > - src_nritems - push_items, push_items); > + src_nritems - push_items, push_items, 1); > copy_extent_buffer(dst, src, > btrfs_node_key_ptr_offset(0), > btrfs_node_key_ptr_offset(src_nritems - push_items), > @@ -3218,12 +3221,18 @@ static noinline int split_node(struct btrfs_trans_handle *trans, > int mid; > int ret; > u32 c_nritems; > + int tree_mod_log_removal = 1; > > c = path->nodes[level]; > WARN_ON(btrfs_header_generation(c) != trans->transid); > if (c == root->node) { > /* trying to split the root, lets make a new one */ > ret = insert_new_root(trans, root, path, level + 1); > + /* > + * removal of root nodes has been logged by > + * tree_mod_log_set_root_pointer due to locking > + */ > + tree_mod_log_removal = 0; > if (ret) > return ret; > } else { > @@ -3261,7 +3270,8 @@ static noinline int split_node(struct btrfs_trans_handle *trans, > (unsigned long)btrfs_header_chunk_tree_uuid(split), > BTRFS_UUID_SIZE); > > - tree_mod_log_eb_copy(root->fs_info, split, c, 0, mid, c_nritems - mid); > + tree_mod_log_eb_copy(root->fs_info, split, c, 0, mid, c_nritems - mid, > + tree_mod_log_removal); > copy_extent_buffer(split, c, > btrfs_node_key_ptr_offset(0), > btrfs_node_key_ptr_offset(mid), > -- > 1.7.1 >-- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html