btrfs: Refactor btrfs_get_extent_fiemap (f3714ef4) · Commits · 戴 / test

fs/btrfs/inode.c

+48 −44

Original line number	Diff line number	Diff line
		@@ -6949,10 +6949,10 @@ struct extent_map btrfs_get_extent_fiemap(struct btrfs_inode inode,
		{
		struct extent_map *em;
		struct extent_map *hole_em = NULL;
		u64 range_start = start;
		u64 delalloc_start = start;
		u64 end;
		u64 found;
		u64 found_end;
		u64 delalloc_len;
		u64 delalloc_end;
		int err = 0;

		em = btrfs_get_extent(inode, NULL, 0, start, len, 0);
		@@ -6980,80 +6980,84 @@ struct extent_map btrfs_get_extent_fiemap(struct btrfs_inode inode,
		em = NULL;

		/* ok, we didn't find anything, lets look for delalloc */
		found = count_range_bits(&inode->io_tree, &range_start,
		delalloc_len = count_range_bits(&inode->io_tree, &delalloc_start,
		end, len, EXTENT_DELALLOC, 1);
		found_end = range_start + found;
		if (found_end < range_start)
		found_end = (u64)-1;
		delalloc_end = delalloc_start + delalloc_len;
		if (delalloc_end < delalloc_start)
		delalloc_end = (u64)-1;

		/*
		* we didn't find anything useful, return
		* the original results from get_extent()
		* We didn't find anything useful, return the original results from
		* get_extent()
		*/
		if (range_start > end \|\| found_end <= start) {
		if (delalloc_start > end \|\| delalloc_end <= start) {
		em = hole_em;
		hole_em = NULL;
		goto out;
		}

		/* adjust the range_start to make sure it doesn't
		* go backwards from the start they passed in
		/*
		* Adjust the delalloc_start to make sure it doesn't go backwards from
		* the start they passed in
		*/
		range_start = max(start, range_start);
		found = found_end - range_start;
		delalloc_start = max(start, delalloc_start);
		delalloc_len = delalloc_end - delalloc_start;

		if (found > 0) {
		u64 hole_start = start;
		if (delalloc_len > 0) {
		u64 hole_start;
		u64 hole_len = len;
		const u64 hole_end = extent_map_end(hole_em);

		em = alloc_extent_map();
		if (!em) {
		err = -ENOMEM;
		goto out;
		}
		em->bdev = NULL;

		ASSERT(hole_em);
		/*
		* when btrfs_get_extent can't find anything it
		* returns one huge hole
		* When btrfs_get_extent can't find anything it returns one
		* huge hole
		*
		* make sure what it found really fits our range, and
		* adjust to make sure it is based on the start from
		* the caller
		* Make sure what it found really fits our range, and adjust to
		* make sure it is based on the start from the caller
		*/
		if (hole_em) {
		u64 calc_end = extent_map_end(hole_em);

		if (calc_end <= start \|\| (hole_em->start > end)) {
		if (hole_end <= start \|\| hole_em->start > end) {
		free_extent_map(hole_em);
		hole_em = NULL;
		} else {
		hole_start = max(hole_em->start, start);
		hole_len = calc_end - hole_start;
		}
		hole_len = hole_end - hole_start;
		}
		em->bdev = NULL;
		if (hole_em && range_start > hole_start) {
		/* our hole starts before our delalloc, so we
		* have to return just the parts of the hole
		* that go until the delalloc starts

		if (hole_em && delalloc_start > hole_start) {
		/*
		* Our hole starts before our delalloc, so we have to
		* return just the parts of the hole that go until the
		* delalloc starts
		*/
		em->len = min(hole_len,
		range_start - hole_start);
		em->len = min(hole_len, delalloc_start - hole_start);
		em->start = hole_start;
		em->orig_start = hole_start;
		/*
		* don't adjust block start at all,
		* it is fixed at EXTENT_MAP_HOLE
		* Don't adjust block start at all, it is fixed at
		* EXTENT_MAP_HOLE
		*/
		em->block_start = hole_em->block_start;
		em->block_len = hole_len;
		if (test_bit(EXTENT_FLAG_PREALLOC, &hole_em->flags))
		set_bit(EXTENT_FLAG_PREALLOC, &em->flags);
		} else {
		em->start = range_start;
		em->len = found;
		em->orig_start = range_start;
		/*
		* Hole is out of passed range or it starts after
		* delalloc range
		*/
		em->start = delalloc_start;
		em->len = delalloc_len;
		em->orig_start = delalloc_start;
		em->block_start = EXTENT_MAP_DELALLOC;
		em->block_len = found;
		em->block_len = delalloc_len;
		}
		} else {
		return hole_em;

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