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/tree-log.c b/fs/btrfs/tree-log.c
index 37b52b8..d017283 100644
--- a/fs/btrfs/tree-log.c
+++ b/fs/btrfs/tree-log.c
@@ -1761,7 +1761,7 @@
BTRFS_TREE_LOG_OBJECTID);
ret = btrfs_free_and_pin_reserved_extent(root,
bytenr, blocksize);
- BUG_ON(ret);
+ BUG_ON(ret); /* -ENOMEM or logic errors */
}
free_extent_buffer(next);
continue;
@@ -1869,20 +1869,26 @@
wret = walk_down_log_tree(trans, log, path, &level, wc);
if (wret > 0)
break;
- if (wret < 0)
+ if (wret < 0) {
ret = wret;
+ goto out;
+ }
wret = walk_up_log_tree(trans, log, path, &level, wc);
if (wret > 0)
break;
- if (wret < 0)
+ if (wret < 0) {
ret = wret;
+ goto out;
+ }
}
/* was the root node processed? if not, catch it here */
if (path->nodes[orig_level]) {
- wc->process_func(log, path->nodes[orig_level], wc,
+ ret = wc->process_func(log, path->nodes[orig_level], wc,
btrfs_header_generation(path->nodes[orig_level]));
+ if (ret)
+ goto out;
if (wc->free) {
struct extent_buffer *next;
@@ -1898,10 +1904,11 @@
BTRFS_TREE_LOG_OBJECTID);
ret = btrfs_free_and_pin_reserved_extent(log, next->start,
next->len);
- BUG_ON(ret);
+ BUG_ON(ret); /* -ENOMEM or logic errors */
}
}
+out:
for (i = 0; i <= orig_level; i++) {
if (path->nodes[i]) {
free_extent_buffer(path->nodes[i]);
@@ -2043,7 +2050,11 @@
* wait for them until later.
*/
ret = btrfs_write_marked_extents(log, &log->dirty_log_pages, mark);
- BUG_ON(ret);
+ if (ret) {
+ btrfs_abort_transaction(trans, root, ret);
+ mutex_unlock(&root->log_mutex);
+ goto out;
+ }
btrfs_set_root_node(&log->root_item, log->node);
@@ -2074,7 +2085,11 @@
}
if (ret) {
- BUG_ON(ret != -ENOSPC);
+ if (ret != -ENOSPC) {
+ btrfs_abort_transaction(trans, root, ret);
+ mutex_unlock(&log_root_tree->log_mutex);
+ goto out;
+ }
root->fs_info->last_trans_log_full_commit = trans->transid;
btrfs_wait_marked_extents(log, &log->dirty_log_pages, mark);
mutex_unlock(&log_root_tree->log_mutex);
@@ -2114,7 +2129,11 @@
ret = btrfs_write_and_wait_marked_extents(log_root_tree,
&log_root_tree->dirty_log_pages,
EXTENT_DIRTY | EXTENT_NEW);
- BUG_ON(ret);
+ if (ret) {
+ btrfs_abort_transaction(trans, root, ret);
+ mutex_unlock(&log_root_tree->log_mutex);
+ goto out_wake_log_root;
+ }
btrfs_wait_marked_extents(log, &log->dirty_log_pages, mark);
btrfs_set_super_log_root(root->fs_info->super_for_commit,
@@ -2323,7 +2342,9 @@
if (ret == -ENOSPC) {
root->fs_info->last_trans_log_full_commit = trans->transid;
ret = 0;
- }
+ } else if (ret < 0)
+ btrfs_abort_transaction(trans, root, ret);
+
btrfs_end_log_trans(root);
return err;
@@ -2354,7 +2375,8 @@
if (ret == -ENOSPC) {
root->fs_info->last_trans_log_full_commit = trans->transid;
ret = 0;
- }
+ } else if (ret < 0 && ret != -ENOENT)
+ btrfs_abort_transaction(trans, root, ret);
btrfs_end_log_trans(root);
return ret;
@@ -3166,13 +3188,20 @@
fs_info->log_root_recovering = 1;
trans = btrfs_start_transaction(fs_info->tree_root, 0);
- BUG_ON(IS_ERR(trans));
+ if (IS_ERR(trans)) {
+ ret = PTR_ERR(trans);
+ goto error;
+ }
wc.trans = trans;
wc.pin = 1;
ret = walk_log_tree(trans, log_root_tree, &wc);
- BUG_ON(ret);
+ if (ret) {
+ btrfs_error(fs_info, ret, "Failed to pin buffers while "
+ "recovering log root tree.");
+ goto error;
+ }
again:
key.objectid = BTRFS_TREE_LOG_OBJECTID;
@@ -3181,8 +3210,12 @@
while (1) {
ret = btrfs_search_slot(NULL, log_root_tree, &key, path, 0, 0);
- if (ret < 0)
- break;
+
+ if (ret < 0) {
+ btrfs_error(fs_info, ret,
+ "Couldn't find tree log root.");
+ goto error;
+ }
if (ret > 0) {
if (path->slots[0] == 0)
break;
@@ -3196,14 +3229,24 @@
log = btrfs_read_fs_root_no_radix(log_root_tree,
&found_key);
- BUG_ON(IS_ERR(log));
+ if (IS_ERR(log)) {
+ ret = PTR_ERR(log);
+ btrfs_error(fs_info, ret,
+ "Couldn't read tree log root.");
+ goto error;
+ }
tmp_key.objectid = found_key.offset;
tmp_key.type = BTRFS_ROOT_ITEM_KEY;
tmp_key.offset = (u64)-1;
wc.replay_dest = btrfs_read_fs_root_no_name(fs_info, &tmp_key);
- BUG_ON(IS_ERR_OR_NULL(wc.replay_dest));
+ if (IS_ERR(wc.replay_dest)) {
+ ret = PTR_ERR(wc.replay_dest);
+ btrfs_error(fs_info, ret, "Couldn't read target root "
+ "for tree log recovery.");
+ goto error;
+ }
wc.replay_dest->log_root = log;
btrfs_record_root_in_trans(trans, wc.replay_dest);
@@ -3251,6 +3294,10 @@
kfree(log_root_tree);
return 0;
+
+error:
+ btrfs_free_path(path);
+ return ret;
}
/*