Patch "Btrfs: bail out if block group has different mixed flag" has been added to the 4.8-stable tree

This is a note to let you know that I've just added the patch titled

Btrfs: bail out if block group has different mixed flag

to the 4.8-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
btrfs-bail-out-if-block-group-has-different-mixed-flag.patch
and it can be found in the queue-4.8 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Liu Bo <[email protected]>
Date: Thu, 25 Aug 2016 18:08:27 -0700
Subject: Btrfs: bail out if block group has different mixed flag

From: Liu Bo <[email protected]>

commit 49303381f19ab16a371a061b67e783d3f570d56e upstream.

Currently we allow inconsistence about mixed flag
(BTRFS_BLOCK_GROUP_METADATA | BTRFS_BLOCK_GROUP_DATA).

We'd get ENOSPC if block group has mixed flag and btrfs doesn't. If that happens, we have one space_info with mixed flag and another space_info only with BTRFS_BLOCK_GROUP_METADATA, and global_block_rsv.space_info points to the latter one, but all bytes from block_group contributes to the mixed space_info, thus all the allocation will fail with ENOSPC.

This adds a check for the above case.

---
 fs/btrfs/extent-tree.c |   14 ++++++++++++++
 1 file changed, 14 insertions(+)

@@ -10127,6 +10127,11 @@ int btrfs_read_block_groups(struct btrfs
 	struct extent_buffer *leaf;
 	int need_clear = 0;
 	u64 cache_gen;
+	u64 feature;
+	int mixed;
+
+	feature = btrfs_super_incompat_flags(info->super_copy);
+	mixed = !!(feature & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS);
 
 	root = info->extent_root;
 	key.objectid = 0;

@@ -10180,6 +10185,15 @@ int btrfs_read_block_groups(struct btrfs
 				   btrfs_item_ptr_offset(leaf, path->slots[0]),
 				   sizeof(cache->item));
 		cache->flags = btrfs_block_group_flags(&cache->item);
+		if (!mixed &&
+		    ((cache->flags & BTRFS_BLOCK_GROUP_METADATA) &&
+		    (cache->flags & BTRFS_BLOCK_GROUP_DATA))) {
+			btrfs_err(info,
+"bg %llu is a mixed block group but filesystem hasn't enabled mixed block groups",
+				  cache->key.objectid);
+			ret = -EINVAL;
+			goto error;
+		}
 
 		key.objectid = found_key.objectid + found_key.offset;
 		btrfs_release_path(path);

Patches currently in stable-queue which might be from [email protected] are

queue-4.8/btrfs-fix-memory-leak-in-reading-btree-blocks.patch queue-4.8/btrfs-fix-emptiness-check-for-dirtied-extent-buffers-at-check_leaf.patch queue-4.8/btrfs-bail-out-if-block-group-has-different-mixed-flag.patch queue-4.8/btrfs-return-gracefully-from-balance-if-fs-tree-is-corrupted.patch queue-4.8/btrfs-don-t-bug-during-drop-snapshot.patch queue-4.8/btrfs-fix-bug_on-in-btrfs_mark_buffer_dirty.patch queue-4.8/btrfs-fix-memory-leak-in-do_walk_down.patch