btrfs-progs: Fix false ENOSPC alert by tracking used space correctly
[BUG] There is a bug report of unexpected ENOSPC from btrfs-convert, issue #123. After some debugging, even when we have enough unallocated space, we still hit ENOSPC at btrfs_reserve_extent(). [CAUSE] Btrfs-progs relies on chunk preallocator to make enough space for data/metadata. However after the introduction of delayed-ref, it's no longer reliable to rely on btrfs_space_info::bytes_used and btrfs_space_info::bytes_pinned to calculate used metadata space. For a running transaction with a lot of allocated tree blocks, btrfs_space_info::bytes_used stays its original value, and will only be updated when running delayed ref. This makes btrfs-progs chunk preallocator completely useless. And for btrfs-convert/mkfs.btrfs --rootdir, if we're going to have enough metadata to fill a metadata block group in one transaction, we will hit ENOSPC no matter whether we have enough unallocated space. [FIX] This patch will introduce btrfs_space_info::bytes_reserved to track how many space we have reserved but not yet committed to extent tree. To support this change, this commit also introduces the following modification: - More comment on btrfs_space_info::bytes_* To make code a little easier to read - Export update_space_info() to preallocate empty data/metadata space info for mkfs. For mkfs, we only have a temporary fs image with SYSTEM chunk only. Export update_space_info() so that we can preallocate empty data/metadata space info before we start a transaction. - Proper btrfs_space_info::bytes_reserved update The timing is the as kernel (except we don't need to update bytes_reserved for data extents) * Increase bytes_reserved when call alloc_reserved_tree_block() * Decrease bytes_reserved when running delayed refs With the help of head->must_insert_reserved to determine whether we need to decrease. Issue: #123 Signed-off-by: Qu Wenruo <wqu@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
Qu Wenruo
David Sterba
parent
ab5079c19a
commit
c31edf610c
24
ctree.h
24
ctree.h
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@ -1058,8 +1058,29 @@ struct btrfs_qgroup_limit_item {
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struct btrfs_space_info {
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u64 flags;
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u64 total_bytes;
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/*
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* Space already used.
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* Only accounting space in current extent tree, thus delayed ref
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* won't be accounted here.
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*/
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u64 bytes_used;
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/*
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* Space being pinned down.
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* So extent allocator will not try to allocate space from them.
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*
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* For cases like extents being freed in current transaction, or
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* manually pinned bytes for re-initializing certain trees.
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*/
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u64 bytes_pinned;
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/*
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* Space being reserved.
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* Space has already being reserved but not yet reach extent tree.
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*
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* New tree blocks allocated in current transaction goes here.
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*/
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u64 bytes_reserved;
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int full;
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struct list_head list;
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};
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@ -2513,6 +2534,9 @@ int btrfs_update_extent_ref(struct btrfs_trans_handle *trans,
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u64 root_objectid, u64 ref_generation,
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u64 owner_objectid);
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int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans);
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int update_space_info(struct btrfs_fs_info *info, u64 flags,
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u64 total_bytes, u64 bytes_used,
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struct btrfs_space_info **space_info);
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int btrfs_free_block_groups(struct btrfs_fs_info *info);
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int btrfs_read_block_groups(struct btrfs_root *root);
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struct btrfs_block_group_cache *
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@ -1630,9 +1630,9 @@ static int free_space_info(struct btrfs_fs_info *fs_info, u64 flags,
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return 0;
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}
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static int update_space_info(struct btrfs_fs_info *info, u64 flags,
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u64 total_bytes, u64 bytes_used,
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struct btrfs_space_info **space_info)
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int update_space_info(struct btrfs_fs_info *info, u64 flags,
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u64 total_bytes, u64 bytes_used,
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struct btrfs_space_info **space_info)
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{
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struct btrfs_space_info *found;
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@ -1658,6 +1658,7 @@ static int update_space_info(struct btrfs_fs_info *info, u64 flags,
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found->total_bytes = total_bytes;
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found->bytes_used = bytes_used;
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found->bytes_pinned = 0;
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found->bytes_reserved = 0;
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found->full = 0;
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*space_info = found;
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return 0;
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@ -1703,8 +1704,8 @@ static int do_chunk_alloc(struct btrfs_trans_handle *trans,
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return 0;
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thresh = div_factor(space_info->total_bytes, 7);
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if ((space_info->bytes_used + space_info->bytes_pinned + alloc_bytes) <
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thresh)
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if ((space_info->bytes_used + space_info->bytes_pinned +
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space_info->bytes_reserved + alloc_bytes) < thresh)
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return 0;
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/*
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@ -2375,6 +2376,7 @@ static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
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struct btrfs_fs_info *fs_info = trans->fs_info;
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struct btrfs_extent_item *extent_item;
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struct btrfs_extent_inline_ref *iref;
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struct btrfs_space_info *sinfo;
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struct extent_buffer *leaf;
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struct btrfs_path *path;
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struct btrfs_key ins;
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@ -2382,6 +2384,9 @@ static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
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u64 start, end;
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int ret;
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sinfo = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
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ASSERT(sinfo);
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ins.objectid = node->bytenr;
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if (skinny_metadata) {
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ins.offset = ref->level;
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@ -2442,6 +2447,14 @@ static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
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ret = update_block_group(fs_info, ins.objectid, fs_info->nodesize, 1,
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0);
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if (sinfo) {
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if (fs_info->nodesize > sinfo->bytes_reserved) {
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WARN_ON(1);
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sinfo->bytes_reserved = 0;
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} else {
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sinfo->bytes_reserved -= fs_info->nodesize;
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}
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}
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if (ref->root == BTRFS_EXTENT_TREE_OBJECTID) {
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clear_extent_bits(&trans->fs_info->extent_ins, start, end,
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@ -2461,6 +2474,8 @@ static int alloc_tree_block(struct btrfs_trans_handle *trans,
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int ret;
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u64 extent_size;
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struct btrfs_delayed_extent_op *extent_op;
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struct btrfs_space_info *sinfo;
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struct btrfs_fs_info *fs_info = root->fs_info;
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bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
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SKINNY_METADATA);
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@ -2468,6 +2483,11 @@ static int alloc_tree_block(struct btrfs_trans_handle *trans,
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if (!extent_op)
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return -ENOMEM;
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sinfo = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
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if (!sinfo) {
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error("Corrupted fs, no valid METADATA block group found");
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return -EUCLEAN;
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}
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ret = btrfs_reserve_extent(trans, root, num_bytes, empty_size,
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hint_byte, search_end, ins, 0);
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if (ret < 0)
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@ -2500,6 +2520,7 @@ static int alloc_tree_block(struct btrfs_trans_handle *trans,
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BUG_ON(ret);
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}
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sinfo->bytes_reserved += extent_size;
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ret = btrfs_add_delayed_tree_ref(root->fs_info, trans, ins->objectid,
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extent_size, 0, root_objectid,
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level, BTRFS_ADD_DELAYED_EXTENT,
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@ -2837,6 +2858,10 @@ int btrfs_free_block_groups(struct btrfs_fs_info *info)
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sinfo = list_entry(info->space_info.next,
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struct btrfs_space_info, list);
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list_del_init(&sinfo->list);
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if (sinfo->bytes_reserved)
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warning(
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"reserved space leaked, flag=0x%llx bytes_reserved=%llu",
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sinfo->flags, sinfo->bytes_reserved);
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kfree(sinfo);
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}
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return 0;
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@ -3943,8 +3968,17 @@ int cleanup_ref_head(struct btrfs_trans_handle *trans,
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rb_erase(&head->href_node, &delayed_refs->href_root);
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RB_CLEAR_NODE(&head->href_node);
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if (head->must_insert_reserved)
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if (head->must_insert_reserved) {
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btrfs_pin_extent(fs_info, head->bytenr, head->num_bytes);
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if (!head->is_data) {
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struct btrfs_space_info *sinfo;
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sinfo = __find_space_info(trans->fs_info,
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BTRFS_BLOCK_GROUP_METADATA);
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ASSERT(sinfo);
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sinfo->bytes_reserved -= head->num_bytes;
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}
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}
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btrfs_put_delayed_ref_head(head);
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return 0;
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11
mkfs/main.c
11
mkfs/main.c
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@ -59,11 +59,22 @@ static int create_metadata_block_groups(struct btrfs_root *root, int mixed,
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{
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struct btrfs_fs_info *fs_info = root->fs_info;
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struct btrfs_trans_handle *trans;
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struct btrfs_space_info *sinfo;
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u64 bytes_used;
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u64 chunk_start = 0;
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u64 chunk_size = 0;
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int ret;
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/* Create needed space info to trace extents reservation */
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ret = update_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA,
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0, 0, &sinfo);
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if (ret < 0)
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return ret;
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ret = update_space_info(fs_info, BTRFS_BLOCK_GROUP_DATA,
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0, 0, &sinfo);
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if (ret < 0)
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return ret;
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trans = btrfs_start_transaction(root, 1);
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BUG_ON(IS_ERR(trans));
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bytes_used = btrfs_super_bytes_used(fs_info->super_copy);
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@ -159,6 +159,7 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
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u64 transid = trans->transid;
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int ret = 0;
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struct btrfs_fs_info *fs_info = root->fs_info;
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struct btrfs_space_info *sinfo;
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if (trans->fs_info->transaction_aborted)
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return -EROFS;
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@ -210,6 +211,13 @@ commit_tree:
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root->commit_root = NULL;
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fs_info->running_transaction = NULL;
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fs_info->last_trans_committed = transid;
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list_for_each_entry(sinfo, &fs_info->space_info, list) {
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if (sinfo->bytes_reserved) {
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warning(
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"reserved space leaked, transid=%llu flag=0x%llx bytes_reserved=%llu",
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transid, sinfo->flags, sinfo->bytes_reserved);
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}
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}
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return ret;
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error:
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btrfs_destroy_delayed_refs(trans);
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