Btrfs: abort the transaction if we fail to update the free space cache inode (0c0ef4bc) · Commits · 戴 / test

Our gluster boxes were hitting a problem where they'd run out of space when updating the block group cache and therefore wouldn't be able to update the free space inode. This is a problem because this is how we invalidate the cache and protect ourselves from errors further down the stack, so if this fails we have to abort the transaction so we make sure we don't end up with stale free space cache. Thanks, Signed-off-by:

Josef Bacik <jbacik@fb.com> Signed-off-by:

Chris Mason <clm@fb.com>

fs/btrfs/extent-tree.c

+16 −0

Original line number	Diff line number	Diff line
		@@ -3208,6 +3208,8 @@ static int cache_save_setup(struct btrfs_block_group_cache *block_group,
		return 0;
		}

		if (trans->aborted)
		return 0;
		again:
		inode = lookup_free_space_inode(root, block_group, path);
		if (IS_ERR(inode) && PTR_ERR(inode) != -ENOENT) {
		@@ -3243,6 +3245,20 @@ again:
		*/
		BTRFS_I(inode)->generation = 0;
		ret = btrfs_update_inode(trans, root, inode);
		if (ret) {
		/*
		* So theoretically we could recover from this, simply set the
		* super cache generation to 0 so we know to invalidate the
		* cache, but then we'd have to keep track of the block groups
		* that fail this way so we know we _have_ to reset this cache
		* before the next commit or risk reading stale cache. So to
		* limit our exposure to horrible edge cases lets just abort the
		* transaction, this only happens in really bad situations
		* anyway.
		*/
		btrfs_abort_transaction(trans, root, ret);
		goto out_put;
		}
		WARN_ON(ret);

		if (i_size_read(inode) > 0) {

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