Btrfs: add pinned extents to on-disk free space cache correctly
I got this while running xfstests:
[24256.836098] block group 317849600 has an wrong amount of free space
[24256.836100] btrfs: failed to load free space cache for block group 317849600
We should clamp the extent returned by find_first_extent_bit(),
so the start of the extent won't smaller than the start of the
block group.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c
index ec23d43..01840ef 100644
--- a/fs/btrfs/free-space-cache.c
+++ b/fs/btrfs/free-space-cache.c
@@ -838,7 +838,7 @@
struct io_ctl io_ctl;
struct list_head bitmap_list;
struct btrfs_key key;
- u64 start, end, len;
+ u64 start, extent_start, extent_end, len;
int entries = 0;
int bitmaps = 0;
int ret;
@@ -857,25 +857,12 @@
struct btrfs_free_cluster,
block_group_list);
- /*
- * We shouldn't have switched the pinned extents yet so this is the
- * right one
- */
- unpin = root->fs_info->pinned_extents;
-
/* Lock all pages first so we can lock the extent safely. */
io_ctl_prepare_pages(&io_ctl, inode, 0);
lock_extent_bits(&BTRFS_I(inode)->io_tree, 0, i_size_read(inode) - 1,
0, &cached_state, GFP_NOFS);
- /*
- * When searching for pinned extents, we need to start at our start
- * offset.
- */
- if (block_group)
- start = block_group->key.objectid;
-
node = rb_first(&ctl->free_space_offset);
if (!node && cluster) {
node = rb_first(&cluster->root);
@@ -918,9 +905,20 @@
* We want to add any pinned extents to our free space cache
* so we don't leak the space
*/
+
+ /*
+ * We shouldn't have switched the pinned extents yet so this is the
+ * right one
+ */
+ unpin = root->fs_info->pinned_extents;
+
+ if (block_group)
+ start = block_group->key.objectid;
+
while (block_group && (start < block_group->key.objectid +
block_group->key.offset)) {
- ret = find_first_extent_bit(unpin, start, &start, &end,
+ ret = find_first_extent_bit(unpin, start,
+ &extent_start, &extent_end,
EXTENT_DIRTY);
if (ret) {
ret = 0;
@@ -928,20 +926,21 @@
}
/* This pinned extent is out of our range */
- if (start >= block_group->key.objectid +
+ if (extent_start >= block_group->key.objectid +
block_group->key.offset)
break;
- len = block_group->key.objectid +
- block_group->key.offset - start;
- len = min(len, end + 1 - start);
+ extent_start = max(extent_start, start);
+ extent_end = min(block_group->key.objectid +
+ block_group->key.offset, extent_end + 1);
+ len = extent_end - extent_start;
entries++;
- ret = io_ctl_add_entry(&io_ctl, start, len, NULL);
+ ret = io_ctl_add_entry(&io_ctl, extent_start, len, NULL);
if (ret)
goto out_nospc;
- start = end + 1;
+ start = extent_end;
}
/* Write out the bitmaps */