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/volumes.c b/fs/btrfs/volumes.c
index 394bf15..57305e8 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -549,10 +549,10 @@
fs_devices->num_can_discard--;
new_device = kmalloc(sizeof(*new_device), GFP_NOFS);
- BUG_ON(!new_device);
+ BUG_ON(!new_device); /* -ENOMEM */
memcpy(new_device, device, sizeof(*new_device));
new_device->name = kstrdup(device->name, GFP_NOFS);
- BUG_ON(device->name && !new_device->name);
+ BUG_ON(device->name && !new_device->name); /* -ENOMEM */
new_device->bdev = NULL;
new_device->writeable = 0;
new_device->in_fs_metadata = 0;
@@ -1036,8 +1036,10 @@
leaf = path->nodes[0];
extent = btrfs_item_ptr(leaf, path->slots[0],
struct btrfs_dev_extent);
+ } else {
+ btrfs_error(root->fs_info, ret, "Slot search failed");
+ goto out;
}
- BUG_ON(ret);
if (device->bytes_used > 0) {
u64 len = btrfs_dev_extent_length(leaf, extent);
@@ -1047,7 +1049,10 @@
spin_unlock(&root->fs_info->free_chunk_lock);
}
ret = btrfs_del_item(trans, root, path);
-
+ if (ret) {
+ btrfs_error(root->fs_info, ret,
+ "Failed to remove dev extent item");
+ }
out:
btrfs_free_path(path);
return ret;
@@ -1117,7 +1122,7 @@
if (ret < 0)
goto error;
- BUG_ON(ret == 0);
+ BUG_ON(ret == 0); /* Corruption */
ret = btrfs_previous_item(root, path, 0, BTRFS_CHUNK_ITEM_KEY);
if (ret) {
@@ -1161,7 +1166,7 @@
if (ret < 0)
goto error;
- BUG_ON(ret == 0);
+ BUG_ON(ret == 0); /* Corruption */
ret = btrfs_previous_item(root, path, BTRFS_DEV_ITEMS_OBJECTID,
BTRFS_DEV_ITEM_KEY);
@@ -1595,7 +1600,7 @@
(unsigned long)btrfs_device_fsid(dev_item),
BTRFS_UUID_SIZE);
device = btrfs_find_device(root, devid, dev_uuid, fs_uuid);
- BUG_ON(!device);
+ BUG_ON(!device); /* Logic error */
if (device->fs_devices->seeding) {
btrfs_set_device_generation(leaf, dev_item,
@@ -1705,7 +1710,7 @@
if (seeding_dev) {
sb->s_flags &= ~MS_RDONLY;
ret = btrfs_prepare_sprout(root);
- BUG_ON(ret);
+ BUG_ON(ret); /* -ENOMEM */
}
device->fs_devices = root->fs_info->fs_devices;
@@ -1743,11 +1748,15 @@
if (seeding_dev) {
ret = init_first_rw_device(trans, root, device);
- BUG_ON(ret);
+ if (ret)
+ goto error_trans;
ret = btrfs_finish_sprout(trans, root);
- BUG_ON(ret);
+ if (ret)
+ goto error_trans;
} else {
ret = btrfs_add_device(trans, root, device);
+ if (ret)
+ goto error_trans;
}
/*
@@ -1757,17 +1766,31 @@
btrfs_clear_space_info_full(root->fs_info);
unlock_chunks(root);
- btrfs_commit_transaction(trans, root);
+ ret = btrfs_commit_transaction(trans, root);
if (seeding_dev) {
mutex_unlock(&uuid_mutex);
up_write(&sb->s_umount);
+ if (ret) /* transaction commit */
+ return ret;
+
ret = btrfs_relocate_sys_chunks(root);
- BUG_ON(ret);
+ if (ret < 0)
+ btrfs_error(root->fs_info, ret,
+ "Failed to relocate sys chunks after "
+ "device initialization. This can be fixed "
+ "using the \"btrfs balance\" command.");
}
return ret;
+
+error_trans:
+ unlock_chunks(root);
+ btrfs_abort_transaction(trans, root, ret);
+ btrfs_end_transaction(trans, root);
+ kfree(device->name);
+ kfree(device);
error:
blkdev_put(bdev, FMODE_EXCL);
if (seeding_dev) {
@@ -1875,10 +1898,20 @@
key.type = BTRFS_CHUNK_ITEM_KEY;
ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
- BUG_ON(ret);
+ if (ret < 0)
+ goto out;
+ else if (ret > 0) { /* Logic error or corruption */
+ btrfs_error(root->fs_info, -ENOENT,
+ "Failed lookup while freeing chunk.");
+ ret = -ENOENT;
+ goto out;
+ }
ret = btrfs_del_item(trans, root, path);
-
+ if (ret < 0)
+ btrfs_error(root->fs_info, ret,
+ "Failed to delete chunk item.");
+out:
btrfs_free_path(path);
return ret;
}
@@ -2040,7 +2073,7 @@
ret = btrfs_search_slot(NULL, chunk_root, &key, path, 0, 0);
if (ret < 0)
goto error;
- BUG_ON(ret == 0);
+ BUG_ON(ret == 0); /* Corruption */
ret = btrfs_previous_item(chunk_root, path, key.objectid,
key.type);
@@ -3334,7 +3367,8 @@
ret = btrfs_make_block_group(trans, extent_root, 0, type,
BTRFS_FIRST_CHUNK_TREE_OBJECTID,
start, num_bytes);
- BUG_ON(ret);
+ if (ret)
+ goto error;
for (i = 0; i < map->num_stripes; ++i) {
struct btrfs_device *device;
@@ -3347,7 +3381,10 @@
info->chunk_root->root_key.objectid,
BTRFS_FIRST_CHUNK_TREE_OBJECTID,
start, dev_offset, stripe_size);
- BUG_ON(ret);
+ if (ret) {
+ btrfs_abort_transaction(trans, extent_root, ret);
+ goto error;
+ }
}
kfree(devices_info);
@@ -3465,7 +3502,8 @@
ret = __finish_chunk_alloc(trans, extent_root, map, chunk_offset,
chunk_size, stripe_size);
- BUG_ON(ret);
+ if (ret)
+ return ret;
return 0;
}
@@ -3497,7 +3535,8 @@
ret = __btrfs_alloc_chunk(trans, extent_root, &map, &chunk_size,
&stripe_size, chunk_offset, alloc_profile);
- BUG_ON(ret);
+ if (ret)
+ return ret;
sys_chunk_offset = chunk_offset + chunk_size;
@@ -3508,10 +3547,12 @@
ret = __btrfs_alloc_chunk(trans, extent_root, &sys_map,
&sys_chunk_size, &sys_stripe_size,
sys_chunk_offset, alloc_profile);
- BUG_ON(ret);
+ if (ret)
+ goto abort;
ret = btrfs_add_device(trans, fs_info->chunk_root, device);
- BUG_ON(ret);
+ if (ret)
+ goto abort;
/*
* Modifying chunk tree needs allocating new blocks from both
@@ -3521,13 +3562,20 @@
*/
ret = __finish_chunk_alloc(trans, extent_root, map, chunk_offset,
chunk_size, stripe_size);
- BUG_ON(ret);
+ if (ret)
+ goto abort;
ret = __finish_chunk_alloc(trans, extent_root, sys_map,
sys_chunk_offset, sys_chunk_size,
sys_stripe_size);
- BUG_ON(ret);
+ if (ret)
+ goto abort;
+
return 0;
+
+abort:
+ btrfs_abort_transaction(trans, root, ret);
+ return ret;
}
int btrfs_chunk_readonly(struct btrfs_root *root, u64 chunk_offset)
@@ -3878,7 +3926,7 @@
do_div(length, map->num_stripes);
buf = kzalloc(sizeof(u64) * map->num_stripes, GFP_NOFS);
- BUG_ON(!buf);
+ BUG_ON(!buf); /* -ENOMEM */
for (i = 0; i < map->num_stripes; i++) {
if (devid && map->stripes[i].dev->devid != devid)
@@ -4039,7 +4087,8 @@
ret = btrfs_map_block(map_tree, rw, logical, &map_length, &bbio,
mirror_num);
- BUG_ON(ret);
+ if (ret) /* -ENOMEM */
+ return ret;
total_devs = bbio->num_stripes;
if (map_length < length) {
@@ -4058,7 +4107,7 @@
while (dev_nr < total_devs) {
if (dev_nr < total_devs - 1) {
bio = bio_clone(first_bio, GFP_NOFS);
- BUG_ON(!bio);
+ BUG_ON(!bio); /* -ENOMEM */
} else {
bio = first_bio;
}
@@ -4212,7 +4261,7 @@
write_lock(&map_tree->map_tree.lock);
ret = add_extent_mapping(&map_tree->map_tree, em);
write_unlock(&map_tree->map_tree.lock);
- BUG_ON(ret);
+ BUG_ON(ret); /* Tree corruption */
free_extent_map(em);
return 0;