btrfs: replace many BUG_ONs with proper error handling
btrfs currently handles most errors with BUG_ON. This patch is a work-in-
progress but aims to handle most errors other than internal logic
errors and ENOMEM more gracefully.
This iteration prevents most crashes but can run into lockups with
the page lock on occasion when the timing "works out."
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index 0eb80cc..d83260d 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -452,7 +452,7 @@
split = alloc_extent_map();
if (!split2)
split2 = alloc_extent_map();
- BUG_ON(!split || !split2);
+ BUG_ON(!split || !split2); /* -ENOMEM */
write_lock(&em_tree->lock);
em = lookup_extent_mapping(em_tree, start, len);
@@ -494,7 +494,7 @@
split->flags = flags;
split->compress_type = em->compress_type;
ret = add_extent_mapping(em_tree, split);
- BUG_ON(ret);
+ BUG_ON(ret); /* Logic error */
free_extent_map(split);
split = split2;
split2 = NULL;
@@ -520,7 +520,7 @@
}
ret = add_extent_mapping(em_tree, split);
- BUG_ON(ret);
+ BUG_ON(ret); /* Logic error */
free_extent_map(split);
split = NULL;
}
@@ -679,7 +679,7 @@
root->root_key.objectid,
new_key.objectid,
start - extent_offset, 0);
- BUG_ON(ret);
+ BUG_ON(ret); /* -ENOMEM */
*hint_byte = disk_bytenr;
}
key.offset = start;
@@ -754,7 +754,7 @@
root->root_key.objectid,
key.objectid, key.offset -
extent_offset, 0);
- BUG_ON(ret);
+ BUG_ON(ret); /* -ENOMEM */
inode_sub_bytes(inode,
extent_end - key.offset);
*hint_byte = disk_bytenr;
@@ -770,7 +770,10 @@
ret = btrfs_del_items(trans, root, path, del_slot,
del_nr);
- BUG_ON(ret);
+ if (ret) {
+ btrfs_abort_transaction(trans, root, ret);
+ goto out;
+ }
del_nr = 0;
del_slot = 0;
@@ -782,11 +785,13 @@
BUG_ON(1);
}
- if (del_nr > 0) {
+ if (!ret && del_nr > 0) {
ret = btrfs_del_items(trans, root, path, del_slot, del_nr);
- BUG_ON(ret);
+ if (ret)
+ btrfs_abort_transaction(trans, root, ret);
}
+out:
btrfs_free_path(path);
return ret;
}
@@ -944,7 +949,10 @@
btrfs_release_path(path);
goto again;
}
- BUG_ON(ret < 0);
+ if (ret < 0) {
+ btrfs_abort_transaction(trans, root, ret);
+ goto out;
+ }
leaf = path->nodes[0];
fi = btrfs_item_ptr(leaf, path->slots[0] - 1,
@@ -963,7 +971,7 @@
ret = btrfs_inc_extent_ref(trans, root, bytenr, num_bytes, 0,
root->root_key.objectid,
ino, orig_offset, 0);
- BUG_ON(ret);
+ BUG_ON(ret); /* -ENOMEM */
if (split == start) {
key.offset = start;
@@ -990,7 +998,7 @@
ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
0, root->root_key.objectid,
ino, orig_offset, 0);
- BUG_ON(ret);
+ BUG_ON(ret); /* -ENOMEM */
}
other_start = 0;
other_end = start;
@@ -1007,7 +1015,7 @@
ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
0, root->root_key.objectid,
ino, orig_offset, 0);
- BUG_ON(ret);
+ BUG_ON(ret); /* -ENOMEM */
}
if (del_nr == 0) {
fi = btrfs_item_ptr(leaf, path->slots[0],
@@ -1025,7 +1033,10 @@
btrfs_mark_buffer_dirty(leaf);
ret = btrfs_del_items(trans, root, path, del_slot, del_nr);
- BUG_ON(ret);
+ if (ret < 0) {
+ btrfs_abort_transaction(trans, root, ret);
+ goto out;
+ }
}
out:
btrfs_free_path(path);
@@ -1666,7 +1677,13 @@
em = btrfs_get_extent(inode, NULL, 0, cur_offset,
alloc_end - cur_offset, 0);
- BUG_ON(IS_ERR_OR_NULL(em));
+ if (IS_ERR_OR_NULL(em)) {
+ if (!em)
+ ret = -ENOMEM;
+ else
+ ret = PTR_ERR(em);
+ break;
+ }
last_byte = min(extent_map_end(em), alloc_end);
actual_end = min_t(u64, extent_map_end(em), offset + len);
last_byte = (last_byte + mask) & ~mask;