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

fs/btrfs/volumes.c

+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