On Tue, Aug 23, 2016 at 6:22 PM, Josef Bacik <jba...@fb.com> wrote:
> Suppose you have the following tree in snap1 on a file system mounted with -o
> inode_cache so that inode numbers are recycled
>
> └── [ 258] a
> └── [ 257] b
>
> and then you remove b, rename a to c, and then re-create b in c so you have
> the
> following tree
>
> └── [ 258] c
> └── [ 257] b
>
> and then you try to do an incremental send you will hit
>
> ASSERT(pending_move == 0);
Hi Josef,
Would you care submitting a regression test for xfstests?
The change looks good to me.
thanks
>
> in process_all_refs(). This is because we assume that any recycling of inodes
> will not have a pending change in our path, which isn't the case. This is the
> case for the DELETE side, since we want to remove the old file using the old
> path, but on the create side we could have a pending move and need to do the
> normal pending rename dance. So remove this ASSERT() and put it after the
> DELETE phase as it makes sense there, and change the CREATE stage to bail if
> we
> have pending_move set. This fixes the ASSERT() and results in the proper send
> stream.
>
> Signed-off-by: Josef Bacik <jba...@fb.com>
> ---
> fs/btrfs/send.c | 36 +++++++++++++++++++++++++++---------
> 1 file changed, 27 insertions(+), 9 deletions(-)
>
> diff --git a/fs/btrfs/send.c b/fs/btrfs/send.c
> index b71dd29..2992ff1 100644
> --- a/fs/btrfs/send.c
> +++ b/fs/btrfs/send.c
> @@ -4063,7 +4063,8 @@ out:
> * generation number, which means that it was deleted and recreated.
> */
> static int process_all_refs(struct send_ctx *sctx,
> - enum btrfs_compare_tree_result cmd)
> + enum btrfs_compare_tree_result cmd,
> + int *pending_move)
> {
> int ret;
> struct btrfs_root *root;
> @@ -4073,7 +4074,6 @@ static int process_all_refs(struct send_ctx *sctx,
> struct extent_buffer *eb;
> int slot;
> iterate_inode_ref_t cb;
> - int pending_move = 0;
>
> path = alloc_path_for_send();
> if (!path)
> @@ -4126,10 +4126,7 @@ static int process_all_refs(struct send_ctx *sctx,
> }
> btrfs_release_path(path);
>
> - ret = process_recorded_refs(sctx, &pending_move);
> - /* Only applicable to an incremental send. */
> - ASSERT(pending_move == 0);
> -
> + ret = process_recorded_refs(sctx, pending_move);
> out:
> btrfs_free_path(path);
> return ret;
> @@ -5521,6 +5518,8 @@ static int changed_inode(struct send_ctx *sctx,
> * deleted and the new one as new.
> */
> if (sctx->cur_inode_new_gen) {
> + int pending_move = 0;
> +
> /*
> * First, process the inode as if it was deleted.
> */
> @@ -5532,11 +5531,19 @@ static int changed_inode(struct send_ctx *sctx,
> sctx->cur_inode_mode = btrfs_inode_mode(
> sctx->right_path->nodes[0], right_ii);
> ret = process_all_refs(sctx,
> - BTRFS_COMPARE_TREE_DELETED);
> + BTRFS_COMPARE_TREE_DELETED,
> &pending_move);
> if (ret < 0)
> goto out;
>
> /*
> + * We are deleting the old inode, which shouldn't have
> + * pending moves affecting it for the delete phase, as
> + * the pending stuff doesn't matter until we are
> talking
> + * about adding the new inode.
> + */
> + ASSERT(pending_move == 0);
> +
> + /*
> * Now process the inode as if it was new.
> */
> sctx->cur_inode_gen = left_gen;
> @@ -5551,10 +5558,21 @@ static int changed_inode(struct send_ctx *sctx,
> ret = send_create_inode_if_needed(sctx);
> if (ret < 0)
> goto out;
> -
> - ret = process_all_refs(sctx, BTRFS_COMPARE_TREE_NEW);
> + ret = process_all_refs(sctx, BTRFS_COMPARE_TREE_NEW,
> &pending_move);
> if (ret < 0)
> goto out;
> +
> + /*
> + * This can happen if we have deleted the old inode
> from
> + * it's parent directory, moved that parent directory
> + * somewhere else, and re-created the inode in that
> same
> + * parent directory. If this occurs we need to treat
> + * this like any other new inode that needs pending
> + * renames processed before we process this inode.
> + */
> + if (pending_move)
> + goto out;
> +
> /*
> * Advance send_progress now as we did not get into
> * process_recorded_refs_if_needed in the new_gen
> case.
> --
> 1.8.3.1
>
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