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authorFilipe Manana <fdmanana@suse.com>2015-05-18 19:11:40 +0100
committerChris Mason <clm@fb.com>2015-05-19 18:04:17 -0700
commita96295965b600f2dc6ad661c4803c86e87db3d7b (patch)
tree77d962c73ba063add20fcc8b47950be4c1ee75a2 /fs
parent2c2ed5aa0154c0be67f98c970de6b5587dbc045a (diff)
downloadkernel-a96295965b600f2dc6ad661c4803c86e87db3d7b.tar.gz
Btrfs: fix racy system chunk allocation when setting block group ro
If while setting a block group read-only we end up allocating a system chunk, through check_system_chunk(), we were not doing it while holding the chunk mutex which is a problem if a concurrent chunk allocation is happening, through do_chunk_alloc(), as it means both block groups can end up using the same logical addresses and physical regions in the device(s). So make sure we hold the chunk mutex. Cc: stable@vger.kernel.org # 4.0+ Fixes: 2f0810880f08 ("btrfs: delete chunk allocation attemp when setting block group ro") Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Chris Mason <clm@fb.com>
Diffstat (limited to 'fs')
-rw-r--r--fs/btrfs/extent-tree.c2
-rw-r--r--fs/btrfs/volumes.c1
2 files changed, 3 insertions, 0 deletions
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 7effed6f2fa6..45e3f086790b 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -8842,7 +8842,9 @@ again:
out:
if (cache->flags & BTRFS_BLOCK_GROUP_SYSTEM) {
alloc_flags = update_block_group_flags(root, cache->flags);
+ lock_chunks(root->fs_info->chunk_root);
check_system_chunk(trans, root, alloc_flags);
+ unlock_chunks(root->fs_info->chunk_root);
}
mutex_unlock(&root->fs_info->ro_block_group_mutex);
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 96aebf3bcd5b..174f5e1e00ab 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -4625,6 +4625,7 @@ int btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
{
u64 chunk_offset;
+ ASSERT(mutex_is_locked(&extent_root->fs_info->chunk_mutex));
chunk_offset = find_next_chunk(extent_root->fs_info);
return __btrfs_alloc_chunk(trans, extent_root, chunk_offset, type);
}