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/inode.c b/fs/btrfs/inode.c
index 2b7d251..40fee13 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -416,7 +416,7 @@
}
if (start == 0) {
trans = btrfs_join_transaction(root, 1);
- BUG_ON(!trans);
+ BUG_ON(IS_ERR(trans));
btrfs_set_trans_block_group(trans, inode);
trans->block_rsv = &root->fs_info->delalloc_block_rsv;
@@ -612,6 +612,7 @@
GFP_NOFS);
trans = btrfs_join_transaction(root, 1);
+ BUG_ON(IS_ERR(trans));
ret = btrfs_reserve_extent(trans, root,
async_extent->compressed_size,
async_extent->compressed_size,
@@ -771,7 +772,7 @@
BUG_ON(root == root->fs_info->tree_root);
trans = btrfs_join_transaction(root, 1);
- BUG_ON(!trans);
+ BUG_ON(IS_ERR(trans));
btrfs_set_trans_block_group(trans, inode);
trans->block_rsv = &root->fs_info->delalloc_block_rsv;
@@ -1049,7 +1050,7 @@
} else {
trans = btrfs_join_transaction(root, 1);
}
- BUG_ON(!trans);
+ BUG_ON(IS_ERR(trans));
cow_start = (u64)-1;
cur_offset = start;
@@ -1704,7 +1705,7 @@
trans = btrfs_join_transaction_nolock(root, 1);
else
trans = btrfs_join_transaction(root, 1);
- BUG_ON(!trans);
+ BUG_ON(IS_ERR(trans));
btrfs_set_trans_block_group(trans, inode);
trans->block_rsv = &root->fs_info->delalloc_block_rsv;
ret = btrfs_update_inode(trans, root, inode);
@@ -1721,6 +1722,7 @@
trans = btrfs_join_transaction_nolock(root, 1);
else
trans = btrfs_join_transaction(root, 1);
+ BUG_ON(IS_ERR(trans));
btrfs_set_trans_block_group(trans, inode);
trans->block_rsv = &root->fs_info->delalloc_block_rsv;
@@ -2382,6 +2384,7 @@
if (root->orphan_block_rsv || root->orphan_item_inserted) {
trans = btrfs_join_transaction(root, 1);
+ BUG_ON(IS_ERR(trans));
btrfs_end_transaction(trans, root);
}
@@ -4350,6 +4353,8 @@
trans = btrfs_join_transaction_nolock(root, 1);
else
trans = btrfs_join_transaction(root, 1);
+ if (IS_ERR(trans))
+ return PTR_ERR(trans);
btrfs_set_trans_block_group(trans, inode);
if (nolock)
ret = btrfs_end_transaction_nolock(trans, root);
@@ -4375,6 +4380,7 @@
return;
trans = btrfs_join_transaction(root, 1);
+ BUG_ON(IS_ERR(trans));
btrfs_set_trans_block_group(trans, inode);
ret = btrfs_update_inode(trans, root, inode);
@@ -5179,6 +5185,8 @@
em = NULL;
btrfs_release_path(root, path);
trans = btrfs_join_transaction(root, 1);
+ if (IS_ERR(trans))
+ return ERR_CAST(trans);
goto again;
}
map = kmap(page);
@@ -5283,8 +5291,8 @@
btrfs_drop_extent_cache(inode, start, start + len - 1, 0);
trans = btrfs_join_transaction(root, 0);
- if (!trans)
- return ERR_PTR(-ENOMEM);
+ if (IS_ERR(trans))
+ return ERR_CAST(trans);
trans->block_rsv = &root->fs_info->delalloc_block_rsv;
@@ -5508,7 +5516,7 @@
* while we look for nocow cross refs
*/
trans = btrfs_join_transaction(root, 0);
- if (!trans)
+ if (IS_ERR(trans))
goto must_cow;
if (can_nocow_odirect(trans, inode, start, len) == 1) {
@@ -5643,7 +5651,7 @@
BUG_ON(!ordered);
trans = btrfs_join_transaction(root, 1);
- if (!trans) {
+ if (IS_ERR(trans)) {
err = -ENOMEM;
goto out;
}