btrfs: fix return value check of btrfs_join_transaction()
The error check of btrfs_join_transaction()/btrfs_join_transaction_nolock()
is added, and the mistake of the error check in several places is
corrected.
For more stable Btrfs, I think that we should reduce BUG_ON().
But, I think that long time is necessary for this.
So, I propose this patch as a short-term solution.
With this patch:
- To more stable Btrfs, the part that should be corrected is clarified.
- The panic isn't done by the NULL pointer reference etc. (even if
BUG_ON() is increased temporarily)
- The error code is returned in the place where the error can be easily
returned.
As a long-term plan:
- BUG_ON() is reduced by using the forced-readonly framework, etc.
Signed-off-by: Tsutomu Itoh <t-itoh@jp.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
index 045c9c2..ea99654 100644
--- a/fs/btrfs/relocation.c
+++ b/fs/btrfs/relocation.c
@@ -2147,6 +2147,12 @@
}
trans = btrfs_join_transaction(rc->extent_root, 1);
+ if (IS_ERR(trans)) {
+ if (!err)
+ btrfs_block_rsv_release(rc->extent_root,
+ rc->block_rsv, num_bytes);
+ return PTR_ERR(trans);
+ }
if (!err) {
if (num_bytes != rc->merging_rsv_size) {
@@ -3222,6 +3228,7 @@
trans = btrfs_join_transaction(root, 0);
if (IS_ERR(trans)) {
btrfs_free_path(path);
+ ret = PTR_ERR(trans);
goto out;
}
@@ -3628,6 +3635,7 @@
set_reloc_control(rc);
trans = btrfs_join_transaction(rc->extent_root, 1);
+ BUG_ON(IS_ERR(trans));
btrfs_commit_transaction(trans, rc->extent_root);
return 0;
}
@@ -3804,7 +3812,10 @@
/* get rid of pinned extents */
trans = btrfs_join_transaction(rc->extent_root, 1);
- btrfs_commit_transaction(trans, rc->extent_root);
+ if (IS_ERR(trans))
+ err = PTR_ERR(trans);
+ else
+ btrfs_commit_transaction(trans, rc->extent_root);
out_free:
btrfs_free_block_rsv(rc->extent_root, rc->block_rsv);
btrfs_free_path(path);
@@ -4125,6 +4136,11 @@
set_reloc_control(rc);
trans = btrfs_join_transaction(rc->extent_root, 1);
+ if (IS_ERR(trans)) {
+ unset_reloc_control(rc);
+ err = PTR_ERR(trans);
+ goto out_free;
+ }
rc->merge_reloc_tree = 1;
@@ -4154,9 +4170,13 @@
unset_reloc_control(rc);
trans = btrfs_join_transaction(rc->extent_root, 1);
- btrfs_commit_transaction(trans, rc->extent_root);
-out:
+ if (IS_ERR(trans))
+ err = PTR_ERR(trans);
+ else
+ btrfs_commit_transaction(trans, rc->extent_root);
+out_free:
kfree(rc);
+out:
while (!list_empty(&reloc_roots)) {
reloc_root = list_entry(reloc_roots.next,
struct btrfs_root, root_list);