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Commit b89203f7 authored by Liu Bo's avatar Liu Bo Committed by Chris Mason
Browse files

Btrfs: fix eof while discarding extents



We miscalculate the length of extents we're discarding, and it leads to
an eof of device.

Reported-by: default avatarDaniel Blueman <daniel@quora.org>
Signed-off-by: default avatarLiu Bo <liubo2009@cn.fujitsu.com>
Signed-off-by: default avatarChris Mason <chris.mason@oracle.com>
parent d95603b2
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+18 −2
Original line number Diff line number Diff line
@@ -3833,6 +3833,7 @@ static int __btrfs_map_block(struct btrfs_mapping_tree *map_tree, int rw,
		int sub_stripes = 0;
		u64 stripes_per_dev = 0;
		u32 remaining_stripes = 0;
		u32 last_stripe = 0;

		if (map->type &
		    (BTRFS_BLOCK_GROUP_RAID0 | BTRFS_BLOCK_GROUP_RAID10)) {
@@ -3846,6 +3847,8 @@ static int __btrfs_map_block(struct btrfs_mapping_tree *map_tree, int rw,
						      stripe_nr_orig,
						      factor,
						      &remaining_stripes);
			div_u64_rem(stripe_nr_end - 1, factor, &last_stripe);
			last_stripe *= sub_stripes;
		}

		for (i = 0; i < num_stripes; i++) {
@@ -3858,16 +3861,29 @@ static int __btrfs_map_block(struct btrfs_mapping_tree *map_tree, int rw,
					 BTRFS_BLOCK_GROUP_RAID10)) {
				bbio->stripes[i].length = stripes_per_dev *
							  map->stripe_len;

				if (i / sub_stripes < remaining_stripes)
					bbio->stripes[i].length +=
						map->stripe_len;

				/*
				 * Special for the first stripe and
				 * the last stripe:
				 *
				 * |-------|...|-------|
				 *     |----------|
				 *    off     end_off
				 */
				if (i < sub_stripes)
					bbio->stripes[i].length -=
						stripe_offset;
				if ((i / sub_stripes + 1) %
				    sub_stripes == remaining_stripes)

				if (stripe_index >= last_stripe &&
				    stripe_index <= (last_stripe +
						     sub_stripes - 1))
					bbio->stripes[i].length -=
						stripe_end_offset;

				if (i == sub_stripes - 1)
					stripe_offset = 0;
			} else