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authorFilipe Manana <fdmanana@suse.com>2016-05-14 16:32:35 +0100
committerFilipe Manana <fdmanana@suse.com>2016-05-30 12:58:23 +0100
commit81e87a736c5581e83f52dc054b368993ec7f16d7 (patch)
tree35fdb32b543fa5e2d3a50d51875e9c2ade2a99a4 /fs
parentBtrfs: fix race setting block group readonly during device replace (diff)
downloadlinux-dev-81e87a736c5581e83f52dc054b368993ec7f16d7.tar.xz
linux-dev-81e87a736c5581e83f52dc054b368993ec7f16d7.zip
Btrfs: fix unprotected assignment of the left cursor for device replace
We were assigning new values to fields of the device replace object without holding the respective lock after processing each device extent. This is important for the left cursor field which can be accessed by a concurrent task running __btrfs_map_block (which, correctly, takes the device replace lock). So change these fields while holding the device replace lock. Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: Josef Bacik <jbacik@fb.com>
Diffstat (limited to 'fs')
-rw-r--r--fs/btrfs/scrub.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c
index 1611572d47bd..19a1eda70361 100644
--- a/fs/btrfs/scrub.c
+++ b/fs/btrfs/scrub.c
@@ -3642,9 +3642,11 @@ int scrub_enumerate_chunks(struct scrub_ctx *sctx,
break;
}
+ btrfs_dev_replace_lock(&fs_info->dev_replace, 1);
dev_replace->cursor_right = found_key.offset + length;
dev_replace->cursor_left = found_key.offset;
dev_replace->item_needs_writeback = 1;
+ btrfs_dev_replace_unlock(&fs_info->dev_replace, 1);
ret = scrub_chunk(sctx, scrub_dev, chunk_offset, length,
found_key.offset, cache, is_dev_replace);
@@ -3718,8 +3720,10 @@ int scrub_enumerate_chunks(struct scrub_ctx *sctx,
break;
}
+ btrfs_dev_replace_lock(&fs_info->dev_replace, 1);
dev_replace->cursor_left = dev_replace->cursor_right;
dev_replace->item_needs_writeback = 1;
+ btrfs_dev_replace_unlock(&fs_info->dev_replace, 1);
skip:
key.offset = found_key.offset + length;
btrfs_release_path(path);