[PATCH 3/6] Btrfs: tree mod log's old roots could still be part of the tree
From: Jan Schmidt <hidden>
Date: 2012-10-23 13:55:29
Subsystem:
btrfs file system, filesystems (vfs and infrastructure), the rest · Maintainers:
Chris Mason, David Sterba, Alexander Viro, Christian Brauner, Linus Torvalds
Tree mod log treated old root buffers as always empty buffers when starting the rewind operations. However, the old root may still be part of the current tree at a lower level, with still some valid entries. Signed-off-by: Jan Schmidt <redacted> --- fs/btrfs/ctree.c | 16 ++++++++++++++-- 1 files changed, 14 insertions(+), 2 deletions(-)
diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index e6b75cc..1b60c56 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c@@ -1239,6 +1239,7 @@ get_old_root(struct btrfs_root *root, u64 time_seq) struct tree_mod_root *old_root = NULL; u64 old_generation = 0; u64 logical; + u32 blocksize; eb = btrfs_read_lock_root_node(root); tm = __tree_mod_log_oldest_root(root->fs_info, root, time_seq);
@@ -1254,10 +1255,21 @@ get_old_root(struct btrfs_root *root, u64 time_seq) } tm = tree_mod_log_search(root->fs_info, logical, time_seq); - if (old_root) + if (old_root && tm && tm->op != MOD_LOG_KEY_REMOVE_WHILE_FREEING) { + blocksize = btrfs_level_size(root, old_root->level); + eb = read_tree_block(root, logical, blocksize, 0); + if (!eb) { + pr_warn("btrfs: failed to read tree block %llu from get_old_root\n", + logical); + WARN_ON(1); + } else { + eb = btrfs_clone_extent_buffer(eb); + } + } else if (old_root) { eb = alloc_dummy_extent_buffer(logical, root->nodesize); - else + } else { eb = btrfs_clone_extent_buffer(root->node); + } btrfs_tree_read_unlock(root->node); free_extent_buffer(root->node); if (!eb)
--
1.7.1