Merge branch 'for-chris-4.10' of git://git.kernel.org/pub/scm/linux/kernel/git/fdmanana/linux into for-linus-4.10

Patches queued up by Filipe:

The most important change is still the fix for the extent tree
corruption that happens due to balance when qgroups are enabled (a
regression introduced in 4.7 by a fix for a regression from the last
qgroups rework). This has been hitting SLE and openSUSE users and QA
very badly, where transactions keep getting aborted when running
delayed references leaving the root filesystem in RO mode and nearly
unusable.  There are fixes here that allow us to run xfstests again
with the integrity checker enabled, which has been impossible since 4.8
(apparently I'm the only one running xfstests with the integrity
checker enabled, which is useful to validate dirtied leafs, like
checking if there are keys out of order, etc).  The rest are just some
trivial fixes, most of them tagged for stable, and two cleanups.

Signed-off-by: Chris Mason <clm@fb.com>

1 files changed, 12 insertions, 22 deletions

diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
index 5d222c8d2213..379711048fb0 100644
--- a/fs/btrfs/relocation.c
+++ b/fs/btrfs/relocation.c
@@ -1388,7 +1388,6 @@ static struct btrfs_root *create_reloc_root(struct btrfs_trans_handle *trans,
 	struct extent_buffer *eb;
 	struct btrfs_root_item *root_item;
 	struct btrfs_key root_key;
-	u64 last_snap = 0;
 	int ret;
 
 	root_item = kmalloc(sizeof(*root_item), GFP_NOFS);
@@ -1399,14 +1398,22 @@ static struct btrfs_root *create_reloc_root(struct btrfs_trans_handle *trans,
 	root_key.offset = objectid;
 
 	if (root->root_key.objectid == objectid) {
+		u64 commit_root_gen;
+
 		/* called by btrfs_init_reloc_root */
 		ret = btrfs_copy_root(trans, root, root->commit_root, &eb,
 				      BTRFS_TREE_RELOC_OBJECTID);
 		BUG_ON(ret);
-
-		last_snap = btrfs_root_last_snapshot(&root->root_item);
-		btrfs_set_root_last_snapshot(&root->root_item,
-					     trans->transid - 1);
+		/*
+		 * Set the last_snapshot field to the generation of the commit
+		 * root - like this ctree.c:btrfs_block_can_be_shared() behaves
+		 * correctly (returns true) when the relocation root is created
+		 * either inside the critical section of a transaction commit
+		 * (through transaction.c:qgroup_account_snapshot()) and when
+		 * it's created before the transaction commit is started.
+		 */
+		commit_root_gen = btrfs_header_generation(root->commit_root);
+		btrfs_set_root_last_snapshot(&root->root_item, commit_root_gen);
 	} else {
 		/*
 		 * called by btrfs_reloc_post_snapshot_hook.
@@ -1430,12 +1437,6 @@ static struct btrfs_root *create_reloc_root(struct btrfs_trans_handle *trans,
 		memset(&root_item->drop_progress, 0,
 		       sizeof(struct btrfs_disk_key));
 		root_item->drop_level = 0;
-		/*
-		 * abuse rtransid, it is safe because it is impossible to
-		 * receive data into a relocation tree.
-		 */
-		btrfs_set_root_rtransid(root_item, last_snap);
-		btrfs_set_root_otransid(root_item, trans->transid);
 	}
 
 	btrfs_tree_unlock(eb);
@@ -2406,9 +2407,6 @@ void merge_reloc_roots(struct reloc_control *rc)
 	struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
 	struct btrfs_root *root;
 	struct btrfs_root *reloc_root;
-	u64 last_snap;
-	u64 otransid;
-	u64 objectid;
 	LIST_HEAD(reloc_roots);
 	int found = 0;
 	int ret = 0;
@@ -2447,14 +2445,6 @@ again:
 			list_del_init(&reloc_root->root_list);
 		}
 
-		/*
-		 * we keep the old last snapshot transid in rtranid when we
-		 * created the relocation tree.
-		 */
-		last_snap = btrfs_root_rtransid(&reloc_root->root_item);
-		otransid = btrfs_root_otransid(&reloc_root->root_item);
-		objectid = reloc_root->root_key.offset;
-
 		ret = btrfs_drop_snapshot(reloc_root, rc->block_rsv, 0, 1);
 		if (ret < 0) {
 			if (list_empty(&reloc_root->root_list))