linux-kernel - [PATCH 4.8 29/85] Btrfs: bail out if block group has different mixed flag

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Date:   Wed,  4 Jan 2017 21:47:14 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Vegard Nossum <vegard.nossum@...cle.com>,
        Liu Bo <bo.li.liu@...cle.com>, David Sterba <dsterba@...e.com>
Subject: [PATCH 4.8 29/85] Btrfs: bail out if block group has different mixed flag

4.8-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Liu Bo <bo.li.liu@...cle.com>

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.

Reported-by: Vegard Nossum <vegard.nossum@...cle.com>
Signed-off-by: Liu Bo <bo.li.liu@...cle.com>
[ updated message ]
Reviewed-by: David Sterba <dsterba@...e.com>
Signed-off-by: David Sterba <dsterba@...e.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

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

--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -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);