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Commit a8c450b2 authored by Chris Mason's avatar Chris Mason Committed by David Woodhouse
Browse files

Btrfs: Reorder tests in set_extent_bit to properly find holes 



Yan Zheng noticed that set_extent_bit was exiting too early when there
was a hole in the map.  The fix is to reorder the tests to check for the
hole first.

Signed-off-by: default avatarChris Mason <chris.mason@oracle.com>
parent 011410bd

fs/btrfs/extent_map.c

+22 −22
Original line number Diff line number Diff line
@@ -712,28 +712,6 @@ int set_extent_bit(struct extent_map_tree *tree, u64 start, u64 end, int bits, 
		}

		goto search_again;

	}

	/*

	 * | ---- desired range ---- |

	 *                        | state |

	 * We need to split the extent, and set the bit

	 * on the first half

	 */

	if (state->start <= end && state->end > end) {

		set = state->state & bits;

		if (exclusive && set) {

			*failed_start = start;

			err = -EEXIST;

			goto out;

		}

		err = split_state(tree, state, prealloc, end + 1);

		BUG_ON(err == -EEXIST);



		prealloc->state |= bits;

		merge_state(tree, prealloc);

		prealloc = NULL;

		goto out;

	}



	/*

	 * | ---- desired range ---- |

	 *     | state | or               | state |
@@ -756,6 +734,28 @@ int set_extent_bit(struct extent_map_tree *tree, u64 start, u64 end, int bits, 
		start = this_end + 1;

		goto search_again;

	}

	/*

	 * | ---- desired range ---- |

	 *                        | state |

	 * We need to split the extent, and set the bit

	 * on the first half

	 */

	if (state->start <= end && state->end > end) {

		set = state->state & bits;

		if (exclusive && set) {

			*failed_start = start;

			err = -EEXIST;

			goto out;

		}

		err = split_state(tree, state, prealloc, end + 1);

		BUG_ON(err == -EEXIST);



		prealloc->state |= bits;

		merge_state(tree, prealloc);

		prealloc = NULL;

		goto out;

	}



	goto search_again;



out: