diff options
author | Stefan Agner <stefan.agner@toradex.com> | 2019-06-18 14:29:35 +0200 |
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committer | Stefan Agner <stefan.agner@toradex.com> | 2019-06-18 14:29:35 +0200 |
commit | d15d0b7a9f89cf5a905ad6802eb23100c8063939 (patch) | |
tree | 84caa660dc73842efa29e116dcb3e32aa81a5cf0 /fs/btrfs/ctree.c | |
parent | e9dcc568b2e968af848bbdb4267ba6cde5457b9e (diff) | |
parent | 858848641fbecd42437e36adc9291b0ce5db379e (diff) |
Merge tag 'v4.19.50-rt22' into toradex_4.19.y-rt
Linux 4.19.50-rt22
Diffstat (limited to 'fs/btrfs/ctree.c')
-rw-r--r-- | fs/btrfs/ctree.c | 115 |
1 files changed, 83 insertions, 32 deletions
diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c index 089b46c4d97f..79ac1ebabaf7 100644 --- a/fs/btrfs/ctree.c +++ b/fs/btrfs/ctree.c @@ -1003,6 +1003,48 @@ static noinline int update_ref_for_cow(struct btrfs_trans_handle *trans, return 0; } +static struct extent_buffer *alloc_tree_block_no_bg_flush( + struct btrfs_trans_handle *trans, + struct btrfs_root *root, + u64 parent_start, + const struct btrfs_disk_key *disk_key, + int level, + u64 hint, + u64 empty_size) +{ + struct btrfs_fs_info *fs_info = root->fs_info; + struct extent_buffer *ret; + + /* + * If we are COWing a node/leaf from the extent, chunk, device or free + * space trees, make sure that we do not finish block group creation of + * pending block groups. We do this to avoid a deadlock. + * COWing can result in allocation of a new chunk, and flushing pending + * block groups (btrfs_create_pending_block_groups()) can be triggered + * when finishing allocation of a new chunk. Creation of a pending block + * group modifies the extent, chunk, device and free space trees, + * therefore we could deadlock with ourselves since we are holding a + * lock on an extent buffer that btrfs_create_pending_block_groups() may + * try to COW later. + * For similar reasons, we also need to delay flushing pending block + * groups when splitting a leaf or node, from one of those trees, since + * we are holding a write lock on it and its parent or when inserting a + * new root node for one of those trees. + */ + if (root == fs_info->extent_root || + root == fs_info->chunk_root || + root == fs_info->dev_root || + root == fs_info->free_space_root) + trans->can_flush_pending_bgs = false; + + ret = btrfs_alloc_tree_block(trans, root, parent_start, + root->root_key.objectid, disk_key, level, + hint, empty_size); + trans->can_flush_pending_bgs = true; + + return ret; +} + /* * does the dirty work in cow of a single block. The parent block (if * supplied) is updated to point to the new cow copy. The new buffer is marked @@ -1050,26 +1092,8 @@ static noinline int __btrfs_cow_block(struct btrfs_trans_handle *trans, if ((root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) && parent) parent_start = parent->start; - /* - * If we are COWing a node/leaf from the extent, chunk or device trees, - * make sure that we do not finish block group creation of pending block - * groups. We do this to avoid a deadlock. - * COWing can result in allocation of a new chunk, and flushing pending - * block groups (btrfs_create_pending_block_groups()) can be triggered - * when finishing allocation of a new chunk. Creation of a pending block - * group modifies the extent, chunk and device trees, therefore we could - * deadlock with ourselves since we are holding a lock on an extent - * buffer that btrfs_create_pending_block_groups() may try to COW later. - */ - if (root == fs_info->extent_root || - root == fs_info->chunk_root || - root == fs_info->dev_root) - trans->can_flush_pending_bgs = false; - - cow = btrfs_alloc_tree_block(trans, root, parent_start, - root->root_key.objectid, &disk_key, level, - search_start, empty_size); - trans->can_flush_pending_bgs = true; + cow = alloc_tree_block_no_bg_flush(trans, root, parent_start, &disk_key, + level, search_start, empty_size); if (IS_ERR(cow)) return PTR_ERR(cow); @@ -2412,6 +2436,16 @@ read_block_for_search(struct btrfs_root *root, struct btrfs_path *p, if (tmp) { /* first we do an atomic uptodate check */ if (btrfs_buffer_uptodate(tmp, gen, 1) > 0) { + /* + * Do extra check for first_key, eb can be stale due to + * being cached, read from scrub, or have multiple + * parents (shared tree blocks). + */ + if (btrfs_verify_level_key(fs_info, tmp, + parent_level - 1, &first_key, gen)) { + free_extent_buffer(tmp); + return -EUCLEAN; + } *eb_ret = tmp; return 0; } @@ -2624,14 +2658,27 @@ static struct extent_buffer *btrfs_search_slot_get_root(struct btrfs_root *root, root_lock = BTRFS_READ_LOCK; if (p->search_commit_root) { - /* The commit roots are read only so we always do read locks */ - if (p->need_commit_sem) + /* + * The commit roots are read only so we always do read locks, + * and we always must hold the commit_root_sem when doing + * searches on them, the only exception is send where we don't + * want to block transaction commits for a long time, so + * we need to clone the commit root in order to avoid races + * with transaction commits that create a snapshot of one of + * the roots used by a send operation. + */ + if (p->need_commit_sem) { down_read(&fs_info->commit_root_sem); - b = root->commit_root; - extent_buffer_get(b); - level = btrfs_header_level(b); - if (p->need_commit_sem) + b = btrfs_clone_extent_buffer(root->commit_root); up_read(&fs_info->commit_root_sem); + if (!b) + return ERR_PTR(-ENOMEM); + + } else { + b = root->commit_root; + extent_buffer_get(b); + } + level = btrfs_header_level(b); /* * Ensure that all callers have set skip_locking when * p->search_commit_root = 1. @@ -2757,6 +2804,10 @@ int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root *root, again: prev_cmp = -1; b = btrfs_search_slot_get_root(root, p, write_lock_level); + if (IS_ERR(b)) { + ret = PTR_ERR(b); + goto done; + } while (b) { level = btrfs_header_level(b); @@ -3364,8 +3415,8 @@ static noinline int insert_new_root(struct btrfs_trans_handle *trans, else btrfs_node_key(lower, &lower_key, 0); - c = btrfs_alloc_tree_block(trans, root, 0, root->root_key.objectid, - &lower_key, level, root->node->start, 0); + c = alloc_tree_block_no_bg_flush(trans, root, 0, &lower_key, level, + root->node->start, 0); if (IS_ERR(c)) return PTR_ERR(c); @@ -3494,8 +3545,8 @@ static noinline int split_node(struct btrfs_trans_handle *trans, mid = (c_nritems + 1) / 2; btrfs_node_key(c, &disk_key, mid); - split = btrfs_alloc_tree_block(trans, root, 0, root->root_key.objectid, - &disk_key, level, c->start, 0); + split = alloc_tree_block_no_bg_flush(trans, root, 0, &disk_key, level, + c->start, 0); if (IS_ERR(split)) return PTR_ERR(split); @@ -4279,8 +4330,8 @@ again: else btrfs_item_key(l, &disk_key, mid); - right = btrfs_alloc_tree_block(trans, root, 0, root->root_key.objectid, - &disk_key, 0, l->start, 0); + right = alloc_tree_block_no_bg_flush(trans, root, 0, &disk_key, 0, + l->start, 0); if (IS_ERR(right)) return PTR_ERR(right); |