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Commit 692826b2 authored by Jeff Mahoney's avatar Jeff Mahoney Committed by David Sterba
Browse files

btrfs: handle errors while updating refcounts in update_ref_for_cow 



Since commit fb235dc0 (btrfs: qgroup: Move half of the qgroup
accounting time out of commit trans) the assumption that
btrfs_add_delayed_{data,tree}_ref can only return 0 or -ENOMEM has
been false.  The qgroup operations call into btrfs_search_slot
and friends and can now return the full spectrum of error codes.

Fortunately, the fix here is easy since update_ref_for_cow failing
is already handled so we just need to bail early with the error
code.

Fixes: fb235dc0 (btrfs: qgroup: Move half of the qgroup accounting ...)
Cc: <stable@vger.kernel.org> # v4.11+
Signed-off-by: default avatarJeff Mahoney <jeffm@suse.com>
Reviewed-by: default avatarEdmund Nadolski <enadolski@suse.com>
Reviewed-by: default avatarQu Wenruo <wqu@suse.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent b430b775

fs/btrfs/ctree.c

+12 −6
Original line number Diff line number Diff line
@@ -1032,14 +1032,17 @@ static noinline int update_ref_for_cow(struct btrfs_trans_handle *trans, 
		     root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) &&

		    !(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF)) {

			ret = btrfs_inc_ref(trans, root, buf, 1);

			BUG_ON(ret); /* -ENOMEM */

			if (ret)

				return ret;



			if (root->root_key.objectid ==

			    BTRFS_TREE_RELOC_OBJECTID) {

				ret = btrfs_dec_ref(trans, root, buf, 0);

				BUG_ON(ret); /* -ENOMEM */

				if (ret)

					return ret;

				ret = btrfs_inc_ref(trans, root, cow, 1);

				BUG_ON(ret); /* -ENOMEM */

				if (ret)

					return ret;

			}

			new_flags |= BTRFS_BLOCK_FLAG_FULL_BACKREF;

		} else {
@@ -1049,7 +1052,8 @@ static noinline int update_ref_for_cow(struct btrfs_trans_handle *trans, 
				ret = btrfs_inc_ref(trans, root, cow, 1);

			else

				ret = btrfs_inc_ref(trans, root, cow, 0);

			BUG_ON(ret); /* -ENOMEM */

			if (ret)

				return ret;

		}

		if (new_flags != 0) {

			int level = btrfs_header_level(buf);
@@ -1068,9 +1072,11 @@ static noinline int update_ref_for_cow(struct btrfs_trans_handle *trans, 
				ret = btrfs_inc_ref(trans, root, cow, 1);

			else

				ret = btrfs_inc_ref(trans, root, cow, 0);

			BUG_ON(ret); /* -ENOMEM */

			if (ret)

				return ret;

			ret = btrfs_dec_ref(trans, root, buf, 1);

			BUG_ON(ret); /* -ENOMEM */

			if (ret)

				return ret;

		}

		clean_tree_block(fs_info, buf);

		*last_ref = 1;