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/disk-io.c b/fs/btrfs/disk-io.c
index 6297a03..16a0cad 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -98,6 +98,7 @@
*/
u64 bio_offset;
struct btrfs_work work;
+ int error;
};
/*
@@ -405,7 +406,7 @@
u64 found_start;
unsigned long len;
struct extent_buffer *eb;
- int ret;
+ int ret = -EIO;
tree = &BTRFS_I(page->mapping->host)->io_tree;
@@ -423,13 +424,20 @@
eb = alloc_extent_buffer(tree, start, len, page);
if (eb == NULL) {
WARN_ON(1);
+ ret = -ENOMEM;
goto out;
}
ret = btree_read_extent_buffer_pages(root, eb, start + PAGE_CACHE_SIZE,
btrfs_header_generation(eb));
- BUG_ON(ret);
+ if (ret) {
+ btrfs_printk(root->fs_info, KERN_WARNING
+ "Failed to checksum dirty buffer @ %llu[%lu]\n",
+ start, len);
+ goto err;
+ }
WARN_ON(!btrfs_header_flag(eb, BTRFS_HEADER_FLAG_WRITTEN));
+ ret = -EIO;
found_start = btrfs_header_bytenr(eb);
if (found_start != start) {
WARN_ON(1);
@@ -444,10 +452,11 @@
goto err;
}
csum_tree_block(root, eb, 0);
+ ret = 0;
err:
free_extent_buffer(eb);
out:
- return 0;
+ return ret;
}
static int check_tree_block_fsid(struct btrfs_root *root,
@@ -718,11 +727,14 @@
static void run_one_async_start(struct btrfs_work *work)
{
struct async_submit_bio *async;
+ int ret;
async = container_of(work, struct async_submit_bio, work);
- async->submit_bio_start(async->inode, async->rw, async->bio,
- async->mirror_num, async->bio_flags,
- async->bio_offset);
+ ret = async->submit_bio_start(async->inode, async->rw, async->bio,
+ async->mirror_num, async->bio_flags,
+ async->bio_offset);
+ if (ret)
+ async->error = ret;
}
static void run_one_async_done(struct btrfs_work *work)
@@ -743,6 +755,12 @@
waitqueue_active(&fs_info->async_submit_wait))
wake_up(&fs_info->async_submit_wait);
+ /* If an error occured we just want to clean up the bio and move on */
+ if (async->error) {
+ bio_endio(async->bio, async->error);
+ return;
+ }
+
async->submit_bio_done(async->inode, async->rw, async->bio,
async->mirror_num, async->bio_flags,
async->bio_offset);
@@ -784,6 +802,8 @@
async->bio_flags = bio_flags;
async->bio_offset = bio_offset;
+ async->error = 0;
+
atomic_inc(&fs_info->nr_async_submits);
if (rw & REQ_SYNC)
@@ -805,15 +825,18 @@
struct bio_vec *bvec = bio->bi_io_vec;
int bio_index = 0;
struct btrfs_root *root;
+ int ret = 0;
WARN_ON(bio->bi_vcnt <= 0);
while (bio_index < bio->bi_vcnt) {
root = BTRFS_I(bvec->bv_page->mapping->host)->root;
- csum_dirty_buffer(root, bvec->bv_page);
+ ret = csum_dirty_buffer(root, bvec->bv_page);
+ if (ret)
+ break;
bio_index++;
bvec++;
}
- return 0;
+ return ret;
}
static int __btree_submit_bio_start(struct inode *inode, int rw,
@@ -825,8 +848,7 @@
* when we're called for a write, we're already in the async
* submission context. Just jump into btrfs_map_bio
*/
- btree_csum_one_bio(bio);
- return 0;
+ return btree_csum_one_bio(bio);
}
static int __btree_submit_bio_done(struct inode *inode, int rw, struct bio *bio,
@@ -1381,7 +1403,7 @@
root->node = read_tree_block(root, btrfs_root_bytenr(&root->root_item),
blocksize, generation);
root->commit_root = btrfs_root_node(root);
- BUG_ON(!root->node);
+ BUG_ON(!root->node); /* -ENOMEM */
out:
if (location->objectid != BTRFS_TREE_LOG_OBJECTID) {
root->ref_cows = 1;
@@ -1618,7 +1640,6 @@
u64 transid;
unsigned long now;
unsigned long delay;
- int ret;
do {
delay = HZ * 30;
@@ -1642,11 +1663,12 @@
transid = cur->transid;
spin_unlock(&root->fs_info->trans_lock);
+ /* If the file system is aborted, this will always fail. */
trans = btrfs_join_transaction(root);
- BUG_ON(IS_ERR(trans));
+ if (IS_ERR(trans))
+ goto sleep;
if (transid == trans->transid) {
- ret = btrfs_commit_transaction(trans, root);
- BUG_ON(ret);
+ btrfs_commit_transaction(trans, root);
} else {
btrfs_end_transaction(trans, root);
}
@@ -2289,7 +2311,7 @@
chunk_root->node = read_tree_block(chunk_root,
btrfs_super_chunk_root(disk_super),
blocksize, generation);
- BUG_ON(!chunk_root->node);
+ BUG_ON(!chunk_root->node); /* -ENOMEM */
if (!test_bit(EXTENT_BUFFER_UPTODATE, &chunk_root->node->bflags)) {
printk(KERN_WARNING "btrfs: failed to read chunk root on %s\n",
sb->s_id);
@@ -2429,21 +2451,31 @@
log_tree_root->node = read_tree_block(tree_root, bytenr,
blocksize,
generation + 1);
+ /* returns with log_tree_root freed on success */
ret = btrfs_recover_log_trees(log_tree_root);
- BUG_ON(ret);
+ if (ret) {
+ btrfs_error(tree_root->fs_info, ret,
+ "Failed to recover log tree");
+ free_extent_buffer(log_tree_root->node);
+ kfree(log_tree_root);
+ goto fail_trans_kthread;
+ }
if (sb->s_flags & MS_RDONLY) {
- ret = btrfs_commit_super(tree_root);
- BUG_ON(ret);
+ ret = btrfs_commit_super(tree_root);
+ if (ret)
+ goto fail_trans_kthread;
}
}
ret = btrfs_find_orphan_roots(tree_root);
- BUG_ON(ret);
+ if (ret)
+ goto fail_trans_kthread;
if (!(sb->s_flags & MS_RDONLY)) {
ret = btrfs_cleanup_fs_roots(fs_info);
- BUG_ON(ret);
+ if (ret) {
+ }
ret = btrfs_recover_relocation(tree_root);
if (ret < 0) {
@@ -2863,6 +2895,8 @@
if (total_errors > max_errors) {
printk(KERN_ERR "btrfs: %d errors while writing supers\n",
total_errors);
+
+ /* This shouldn't happen. FUA is masked off if unsupported */
BUG();
}
@@ -2879,9 +2913,9 @@
}
mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
if (total_errors > max_errors) {
- printk(KERN_ERR "btrfs: %d errors while writing supers\n",
- total_errors);
- BUG();
+ btrfs_error(root->fs_info, -EIO,
+ "%d errors while writing supers", total_errors);
+ return -EIO;
}
return 0;
}
@@ -3014,14 +3048,21 @@
if (IS_ERR(trans))
return PTR_ERR(trans);
ret = btrfs_commit_transaction(trans, root);
- BUG_ON(ret);
+ if (ret)
+ return ret;
/* run commit again to drop the original snapshot */
trans = btrfs_join_transaction(root);
if (IS_ERR(trans))
return PTR_ERR(trans);
- btrfs_commit_transaction(trans, root);
+ ret = btrfs_commit_transaction(trans, root);
+ if (ret)
+ return ret;
ret = btrfs_write_and_wait_transaction(NULL, root);
- BUG_ON(ret);
+ if (ret) {
+ btrfs_error(root->fs_info, ret,
+ "Failed to sync btree inode to disk.");
+ return ret;
+ }
ret = write_ctree_super(NULL, root, 0);
return ret;
@@ -3366,8 +3407,8 @@
spin_unlock(&root->fs_info->ordered_extent_lock);
}
-static int btrfs_destroy_delayed_refs(struct btrfs_transaction *trans,
- struct btrfs_root *root)
+int btrfs_destroy_delayed_refs(struct btrfs_transaction *trans,
+ struct btrfs_root *root)
{
struct rb_node *node;
struct btrfs_delayed_ref_root *delayed_refs;
@@ -3376,6 +3417,7 @@
delayed_refs = &trans->delayed_refs;
+again:
spin_lock(&delayed_refs->lock);
if (delayed_refs->num_entries == 0) {
spin_unlock(&delayed_refs->lock);
@@ -3397,6 +3439,7 @@
struct btrfs_delayed_ref_head *head;
head = btrfs_delayed_node_to_head(ref);
+ spin_unlock(&delayed_refs->lock);
mutex_lock(&head->mutex);
kfree(head->extent_op);
delayed_refs->num_heads--;
@@ -3404,8 +3447,9 @@
delayed_refs->num_heads_ready--;
list_del_init(&head->cluster);
mutex_unlock(&head->mutex);
+ btrfs_put_delayed_ref(ref);
+ goto again;
}
-
spin_unlock(&delayed_refs->lock);
btrfs_put_delayed_ref(ref);
@@ -3649,6 +3693,17 @@
return 0;
}
+static int btree_writepage_io_failed_hook(struct bio *bio, struct page *page,
+ u64 start, u64 end,
+ struct extent_state *state)
+{
+ struct super_block *sb = page->mapping->host->i_sb;
+ struct btrfs_fs_info *fs_info = btrfs_sb(sb);
+ btrfs_error(fs_info, -EIO,
+ "Error occured while writing out btree at %llu", start);
+ return -EIO;
+}
+
static struct extent_io_ops btree_extent_io_ops = {
.write_cache_pages_lock_hook = btree_lock_page_hook,
.readpage_end_io_hook = btree_readpage_end_io_hook,
@@ -3656,4 +3711,5 @@
.submit_bio_hook = btree_submit_bio_hook,
/* note we're sharing with inode.c for the merge bio hook */
.merge_bio_hook = btrfs_merge_bio_hook,
+ .writepage_io_failed_hook = btree_writepage_io_failed_hook,
};