Merge branch 'for-linus-4.1' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs
Pull btrfs fixes from Chris Mason:
"I fixed up a regression from 4.0 where conversion between different
raid levels would sometimes bail out without converting.
Filipe tracked down a race where it was possible to double allocate
chunks on the drive.
Mark has a fix for fiemap. All three will get bundled off for stable
as well"
* 'for-linus-4.1' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs:
Btrfs: fix regression in raid level conversion
Btrfs: fix racy system chunk allocation when setting block group ro
btrfs: clear 'ret' in btrfs_check_shared() loop
diff --git a/fs/btrfs/backref.c b/fs/btrfs/backref.c
index 9de772e..614aaa1 100644
--- a/fs/btrfs/backref.c
+++ b/fs/btrfs/backref.c
@@ -880,6 +880,8 @@
* indirect refs to their parent bytenr.
* When roots are found, they're added to the roots list
*
+ * NOTE: This can return values > 0
+ *
* FIXME some caching might speed things up
*/
static int find_parent_nodes(struct btrfs_trans_handle *trans,
@@ -1198,6 +1200,19 @@
return ret;
}
+/**
+ * btrfs_check_shared - tell us whether an extent is shared
+ *
+ * @trans: optional trans handle
+ *
+ * btrfs_check_shared uses the backref walking code but will short
+ * circuit as soon as it finds a root or inode that doesn't match the
+ * one passed in. This provides a significant performance benefit for
+ * callers (such as fiemap) which want to know whether the extent is
+ * shared but do not need a ref count.
+ *
+ * Return: 0 if extent is not shared, 1 if it is shared, < 0 on error.
+ */
int btrfs_check_shared(struct btrfs_trans_handle *trans,
struct btrfs_fs_info *fs_info, u64 root_objectid,
u64 inum, u64 bytenr)
@@ -1226,11 +1241,13 @@
ret = find_parent_nodes(trans, fs_info, bytenr, elem.seq, tmp,
roots, NULL, root_objectid, inum);
if (ret == BACKREF_FOUND_SHARED) {
+ /* this is the only condition under which we return 1 */
ret = 1;
break;
}
if (ret < 0 && ret != -ENOENT)
break;
+ ret = 0;
node = ulist_next(tmp, &uiter);
if (!node)
break;
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 7effed6..0ec3acd 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -8829,6 +8829,24 @@
goto again;
}
+ /*
+ * if we are changing raid levels, try to allocate a corresponding
+ * block group with the new raid level.
+ */
+ alloc_flags = update_block_group_flags(root, cache->flags);
+ if (alloc_flags != cache->flags) {
+ ret = do_chunk_alloc(trans, root, alloc_flags,
+ CHUNK_ALLOC_FORCE);
+ /*
+ * ENOSPC is allowed here, we may have enough space
+ * already allocated at the new raid level to
+ * carry on
+ */
+ if (ret == -ENOSPC)
+ ret = 0;
+ if (ret < 0)
+ goto out;
+ }
ret = set_block_group_ro(cache, 0);
if (!ret)
@@ -8842,7 +8860,9 @@
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 96aebf3..174f5e1 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -4625,6 +4625,7 @@
{
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);
}