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-rw-r--r--fs/btrfs/ctree.c30
-rw-r--r--fs/btrfs/disk-io.c14
-rw-r--r--fs/btrfs/extent-tree.c84
-rw-r--r--fs/btrfs/extent_io.c33
-rw-r--r--fs/btrfs/extent_io.h2
-rw-r--r--fs/btrfs/file-item.c6
-rw-r--r--fs/btrfs/file.c9
-rw-r--r--fs/btrfs/inode.c22
-rw-r--r--fs/btrfs/ordered-data.c2
-rw-r--r--fs/btrfs/qgroup.c3
-rw-r--r--fs/btrfs/scrub.c3
-rw-r--r--fs/btrfs/send.c10
-rw-r--r--fs/btrfs/volumes.c13
13 files changed, 188 insertions, 43 deletions
diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index ecd25a1b4e51..ca9d8f1a3bb6 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -651,6 +651,8 @@ tree_mod_log_insert_root(struct btrfs_fs_info *fs_info,
if (tree_mod_dont_log(fs_info, NULL))
return 0;
+ __tree_mod_log_free_eb(fs_info, old_root);
+
ret = tree_mod_alloc(fs_info, flags, &tm);
if (ret < 0)
goto out;
@@ -736,7 +738,7 @@ tree_mod_log_search(struct btrfs_fs_info *fs_info, u64 start, u64 min_seq)
static noinline void
tree_mod_log_eb_copy(struct btrfs_fs_info *fs_info, struct extent_buffer *dst,
struct extent_buffer *src, unsigned long dst_offset,
- unsigned long src_offset, int nr_items)
+ unsigned long src_offset, int nr_items, int log_removal)
{
int ret;
int i;
@@ -750,10 +752,12 @@ tree_mod_log_eb_copy(struct btrfs_fs_info *fs_info, struct extent_buffer *dst,
}
for (i = 0; i < nr_items; i++) {
- ret = tree_mod_log_insert_key_locked(fs_info, src,
- i + src_offset,
- MOD_LOG_KEY_REMOVE);
- BUG_ON(ret < 0);
+ if (log_removal) {
+ ret = tree_mod_log_insert_key_locked(fs_info, src,
+ i + src_offset,
+ MOD_LOG_KEY_REMOVE);
+ BUG_ON(ret < 0);
+ }
ret = tree_mod_log_insert_key_locked(fs_info, dst,
i + dst_offset,
MOD_LOG_KEY_ADD);
@@ -927,7 +931,6 @@ static noinline int update_ref_for_cow(struct btrfs_trans_handle *trans,
ret = btrfs_dec_ref(trans, root, buf, 1, 1);
BUG_ON(ret); /* -ENOMEM */
}
- tree_mod_log_free_eb(root->fs_info, buf);
clean_tree_block(trans, root, buf);
*last_ref = 1;
}
@@ -1046,6 +1049,7 @@ static noinline int __btrfs_cow_block(struct btrfs_trans_handle *trans,
btrfs_set_node_ptr_generation(parent, parent_slot,
trans->transid);
btrfs_mark_buffer_dirty(parent);
+ tree_mod_log_free_eb(root->fs_info, buf);
btrfs_free_tree_block(trans, root, buf, parent_start,
last_ref);
}
@@ -1750,7 +1754,6 @@ static noinline int balance_level(struct btrfs_trans_handle *trans,
goto enospc;
}
- tree_mod_log_free_eb(root->fs_info, root->node);
tree_mod_log_set_root_pointer(root, child);
rcu_assign_pointer(root->node, child);
@@ -2995,7 +2998,7 @@ static int push_node_left(struct btrfs_trans_handle *trans,
push_items = min(src_nritems - 8, push_items);
tree_mod_log_eb_copy(root->fs_info, dst, src, dst_nritems, 0,
- push_items);
+ push_items, 1);
copy_extent_buffer(dst, src,
btrfs_node_key_ptr_offset(dst_nritems),
btrfs_node_key_ptr_offset(0),
@@ -3066,7 +3069,7 @@ static int balance_node_right(struct btrfs_trans_handle *trans,
sizeof(struct btrfs_key_ptr));
tree_mod_log_eb_copy(root->fs_info, dst, src, 0,
- src_nritems - push_items, push_items);
+ src_nritems - push_items, push_items, 1);
copy_extent_buffer(dst, src,
btrfs_node_key_ptr_offset(0),
btrfs_node_key_ptr_offset(src_nritems - push_items),
@@ -3218,12 +3221,18 @@ static noinline int split_node(struct btrfs_trans_handle *trans,
int mid;
int ret;
u32 c_nritems;
+ int tree_mod_log_removal = 1;
c = path->nodes[level];
WARN_ON(btrfs_header_generation(c) != trans->transid);
if (c == root->node) {
/* trying to split the root, lets make a new one */
ret = insert_new_root(trans, root, path, level + 1);
+ /*
+ * removal of root nodes has been logged by
+ * tree_mod_log_set_root_pointer due to locking
+ */
+ tree_mod_log_removal = 0;
if (ret)
return ret;
} else {
@@ -3261,7 +3270,8 @@ static noinline int split_node(struct btrfs_trans_handle *trans,
(unsigned long)btrfs_header_chunk_tree_uuid(split),
BTRFS_UUID_SIZE);
- tree_mod_log_eb_copy(root->fs_info, split, c, 0, mid, c_nritems - mid);
+ tree_mod_log_eb_copy(root->fs_info, split, c, 0, mid, c_nritems - mid,
+ tree_mod_log_removal);
copy_extent_buffer(split, c,
btrfs_node_key_ptr_offset(0),
btrfs_node_key_ptr_offset(mid),
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 7d84651e850b..6d19a0a554aa 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -1291,6 +1291,7 @@ struct btrfs_root *btrfs_create_tree(struct btrfs_trans_handle *trans,
0, objectid, NULL, 0, 0, 0);
if (IS_ERR(leaf)) {
ret = PTR_ERR(leaf);
+ leaf = NULL;
goto fail;
}
@@ -1334,11 +1335,16 @@ struct btrfs_root *btrfs_create_tree(struct btrfs_trans_handle *trans,
btrfs_tree_unlock(leaf);
+ return root;
+
fail:
- if (ret)
- return ERR_PTR(ret);
+ if (leaf) {
+ btrfs_tree_unlock(leaf);
+ free_extent_buffer(leaf);
+ }
+ kfree(root);
- return root;
+ return ERR_PTR(ret);
}
static struct btrfs_root *alloc_log_tree(struct btrfs_trans_handle *trans,
@@ -3253,7 +3259,7 @@ void btrfs_free_fs_root(struct btrfs_fs_info *fs_info, struct btrfs_root *root)
if (btrfs_root_refs(&root->root_item) == 0)
synchronize_srcu(&fs_info->subvol_srcu);
- if (fs_info->fs_state & BTRFS_SUPER_FLAG_ERROR) {
+ if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state)) {
btrfs_free_log(NULL, root);
btrfs_free_log_root_tree(NULL, fs_info);
}
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 9ac2eca681eb..3d551231caba 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -257,7 +257,8 @@ static int exclude_super_stripes(struct btrfs_root *root,
cache->bytes_super += stripe_len;
ret = add_excluded_extent(root, cache->key.objectid,
stripe_len);
- BUG_ON(ret); /* -ENOMEM */
+ if (ret)
+ return ret;
}
for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
@@ -265,13 +266,17 @@ static int exclude_super_stripes(struct btrfs_root *root,
ret = btrfs_rmap_block(&root->fs_info->mapping_tree,
cache->key.objectid, bytenr,
0, &logical, &nr, &stripe_len);
- BUG_ON(ret); /* -ENOMEM */
+ if (ret)
+ return ret;
while (nr--) {
cache->bytes_super += stripe_len;
ret = add_excluded_extent(root, logical[nr],
stripe_len);
- BUG_ON(ret); /* -ENOMEM */
+ if (ret) {
+ kfree(logical);
+ return ret;
+ }
}
kfree(logical);
@@ -4438,7 +4443,7 @@ static void update_global_block_rsv(struct btrfs_fs_info *fs_info)
spin_lock(&sinfo->lock);
spin_lock(&block_rsv->lock);
- block_rsv->size = num_bytes;
+ block_rsv->size = min_t(u64, num_bytes, 512 * 1024 * 1024);
num_bytes = sinfo->bytes_used + sinfo->bytes_pinned +
sinfo->bytes_reserved + sinfo->bytes_readonly +
@@ -4793,14 +4798,49 @@ out_fail:
* If the inodes csum_bytes is the same as the original
* csum_bytes then we know we haven't raced with any free()ers
* so we can just reduce our inodes csum bytes and carry on.
- * Otherwise we have to do the normal free thing to account for
- * the case that the free side didn't free up its reserve
- * because of this outstanding reservation.
*/
- if (BTRFS_I(inode)->csum_bytes == csum_bytes)
+ if (BTRFS_I(inode)->csum_bytes == csum_bytes) {
calc_csum_metadata_size(inode, num_bytes, 0);
- else
- to_free = calc_csum_metadata_size(inode, num_bytes, 0);
+ } else {
+ u64 orig_csum_bytes = BTRFS_I(inode)->csum_bytes;
+ u64 bytes;
+
+ /*
+ * This is tricky, but first we need to figure out how much we
+ * free'd from any free-ers that occured during this
+ * reservation, so we reset ->csum_bytes to the csum_bytes
+ * before we dropped our lock, and then call the free for the
+ * number of bytes that were freed while we were trying our
+ * reservation.
+ */
+ bytes = csum_bytes - BTRFS_I(inode)->csum_bytes;
+ BTRFS_I(inode)->csum_bytes = csum_bytes;
+ to_free = calc_csum_metadata_size(inode, bytes, 0);
+
+
+ /*
+ * Now we need to see how much we would have freed had we not
+ * been making this reservation and our ->csum_bytes were not
+ * artificially inflated.
+ */
+ BTRFS_I(inode)->csum_bytes = csum_bytes - num_bytes;
+ bytes = csum_bytes - orig_csum_bytes;
+ bytes = calc_csum_metadata_size(inode, bytes, 0);
+
+ /*
+ * Now reset ->csum_bytes to what it should be. If bytes is
+ * more than to_free then we would have free'd more space had we
+ * not had an artificially high ->csum_bytes, so we need to free
+ * the remainder. If bytes is the same or less then we don't
+ * need to do anything, the other free-ers did the correct
+ * thing.
+ */
+ BTRFS_I(inode)->csum_bytes = orig_csum_bytes - num_bytes;
+ if (bytes > to_free)
+ to_free = bytes - to_free;
+ else
+ to_free = 0;
+ }
spin_unlock(&BTRFS_I(inode)->lock);
if (dropped)
to_free += btrfs_calc_trans_metadata_size(root, dropped);
@@ -7947,7 +7987,17 @@ int btrfs_read_block_groups(struct btrfs_root *root)
* info has super bytes accounted for, otherwise we'll think
* we have more space than we actually do.
*/
- exclude_super_stripes(root, cache);
+ ret = exclude_super_stripes(root, cache);
+ if (ret) {
+ /*
+ * We may have excluded something, so call this just in
+ * case.
+ */
+ free_excluded_extents(root, cache);
+ kfree(cache->free_space_ctl);
+ kfree(cache);
+ goto error;
+ }
/*
* check for two cases, either we are full, and therefore
@@ -8089,7 +8139,17 @@ int btrfs_make_block_group(struct btrfs_trans_handle *trans,
cache->last_byte_to_unpin = (u64)-1;
cache->cached = BTRFS_CACHE_FINISHED;
- exclude_super_stripes(root, cache);
+ ret = exclude_super_stripes(root, cache);
+ if (ret) {
+ /*
+ * We may have excluded something, so call this just in
+ * case.
+ */
+ free_excluded_extents(root, cache);
+ kfree(cache->free_space_ctl);
+ kfree(cache);
+ return ret;
+ }
add_new_free_space(cache, root->fs_info, chunk_offset,
chunk_offset + size);
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index f173c5af6461..cdee391fc7bf 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -1257,6 +1257,39 @@ int unlock_extent(struct extent_io_tree *tree, u64 start, u64 end)
GFP_NOFS);
}
+int extent_range_clear_dirty_for_io(struct inode *inode, u64 start, u64 end)
+{
+ unsigned long index = start >> PAGE_CACHE_SHIFT;
+ unsigned long end_index = end >> PAGE_CACHE_SHIFT;
+ struct page *page;
+
+ while (index <= end_index) {
+ page = find_get_page(inode->i_mapping, index);
+ BUG_ON(!page); /* Pages should be in the extent_io_tree */
+ clear_page_dirty_for_io(page);
+ page_cache_release(page);
+ index++;
+ }
+ return 0;
+}
+
+int extent_range_redirty_for_io(struct inode *inode, u64 start, u64 end)
+{
+ unsigned long index = start >> PAGE_CACHE_SHIFT;
+ unsigned long end_index = end >> PAGE_CACHE_SHIFT;
+ struct page *page;
+
+ while (index <= end_index) {
+ page = find_get_page(inode->i_mapping, index);
+ BUG_ON(!page); /* Pages should be in the extent_io_tree */
+ account_page_redirty(page);
+ __set_page_dirty_nobuffers(page);
+ page_cache_release(page);
+ index++;
+ }
+ return 0;
+}
+
/*
* helper function to set both pages and extents in the tree writeback
*/
diff --git a/fs/btrfs/extent_io.h b/fs/btrfs/extent_io.h
index 6068a1985560..258c92156857 100644
--- a/fs/btrfs/extent_io.h
+++ b/fs/btrfs/extent_io.h
@@ -325,6 +325,8 @@ int map_private_extent_buffer(struct extent_buffer *eb, unsigned long offset,
unsigned long *map_len);
int extent_range_uptodate(struct extent_io_tree *tree,
u64 start, u64 end);
+int extent_range_clear_dirty_for_io(struct inode *inode, u64 start, u64 end);
+int extent_range_redirty_for_io(struct inode *inode, u64 start, u64 end);
int extent_clear_unlock_delalloc(struct inode *inode,
struct extent_io_tree *tree,
u64 start, u64 end, struct page *locked_page,
diff --git a/fs/btrfs/file-item.c b/fs/btrfs/file-item.c
index ec160202be3e..c4628a201cb3 100644
--- a/fs/btrfs/file-item.c
+++ b/fs/btrfs/file-item.c
@@ -118,9 +118,11 @@ struct btrfs_csum_item *btrfs_lookup_csum(struct btrfs_trans_handle *trans,
csums_in_item = btrfs_item_size_nr(leaf, path->slots[0]);
csums_in_item /= csum_size;
- if (csum_offset >= csums_in_item) {
+ if (csum_offset == csums_in_item) {
ret = -EFBIG;
goto fail;
+ } else if (csum_offset > csums_in_item) {
+ goto fail;
}
}
item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_csum_item);
@@ -728,7 +730,6 @@ int btrfs_csum_file_blocks(struct btrfs_trans_handle *trans,
return -ENOMEM;
sector_sum = sums->sums;
- trans->adding_csums = 1;
again:
next_offset = (u64)-1;
found_next = 0;
@@ -899,7 +900,6 @@ next_sector:
goto again;
}
out:
- trans->adding_csums = 0;
btrfs_free_path(path);
return ret;
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index 5b4ea5f55b8f..ade03e6f7bd2 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -2142,6 +2142,7 @@ static long btrfs_fallocate(struct file *file, int mode,
{
struct inode *inode = file_inode(file);
struct extent_state *cached_state = NULL;
+ struct btrfs_root *root = BTRFS_I(inode)->root;
u64 cur_offset;
u64 last_byte;
u64 alloc_start;
@@ -2169,6 +2170,11 @@ static long btrfs_fallocate(struct file *file, int mode,
ret = btrfs_check_data_free_space(inode, alloc_end - alloc_start);
if (ret)
return ret;
+ if (root->fs_info->quota_enabled) {
+ ret = btrfs_qgroup_reserve(root, alloc_end - alloc_start);
+ if (ret)
+ goto out_reserve_fail;
+ }
/*
* wait for ordered IO before we have any locks. We'll loop again
@@ -2272,6 +2278,9 @@ static long btrfs_fallocate(struct file *file, int mode,
&cached_state, GFP_NOFS);
out:
mutex_unlock(&inode->i_mutex);
+ if (root->fs_info->quota_enabled)
+ btrfs_qgroup_free(root, alloc_end - alloc_start);
+out_reserve_fail:
/* Let go of our reservation. */
btrfs_free_reserved_data_space(inode, alloc_end - alloc_start);
return ret;
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index ca1b767d51f7..09c58a35b429 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -353,6 +353,7 @@ static noinline int compress_file_range(struct inode *inode,
int i;
int will_compress;
int compress_type = root->fs_info->compress_type;
+ int redirty = 0;
/* if this is a small write inside eof, kick off a defrag */
if ((end - start + 1) < 16 * 1024 &&
@@ -415,6 +416,17 @@ again:
if (BTRFS_I(inode)->force_compress)
compress_type = BTRFS_I(inode)->force_compress;
+ /*
+ * we need to call clear_page_dirty_for_io on each
+ * page in the range. Otherwise applications with the file
+ * mmap'd can wander in and change the page contents while
+ * we are compressing them.
+ *
+ * If the compression fails for any reason, we set the pages
+ * dirty again later on.
+ */
+ extent_range_clear_dirty_for_io(inode, start, end);
+ redirty = 1;
ret = btrfs_compress_pages(compress_type,
inode->i_mapping, start,
total_compressed, pages,
@@ -554,6 +566,8 @@ cleanup_and_bail_uncompressed:
__set_page_dirty_nobuffers(locked_page);
/* unlocked later on in the async handlers */
}
+ if (redirty)
+ extent_range_redirty_for_io(inode, start, end);
add_async_extent(async_cow, start, end - start + 1,
0, NULL, 0, BTRFS_COMPRESS_NONE);
*num_added += 1;
@@ -1743,8 +1757,10 @@ static noinline int add_pending_csums(struct btrfs_trans_handle *trans,
struct btrfs_ordered_sum *sum;
list_for_each_entry(sum, list, list) {
+ trans->adding_csums = 1;
btrfs_csum_file_blocks(trans,
BTRFS_I(inode)->root->fs_info->csum_root, sum);
+ trans->adding_csums = 0;
}
return 0;
}
@@ -3679,11 +3695,9 @@ static struct btrfs_trans_handle *__unlink_start_trans(struct inode *dir,
* 1 for the dir item
* 1 for the dir index
* 1 for the inode ref
- * 1 for the inode ref in the tree log
- * 2 for the dir entries in the log
* 1 for the inode
*/
- trans = btrfs_start_transaction(root, 8);
+ trans = btrfs_start_transaction(root, 5);
if (!IS_ERR(trans) || PTR_ERR(trans) != -ENOSPC)
return trans;
@@ -8127,7 +8141,7 @@ static int btrfs_rename(struct inode *old_dir, struct dentry *old_dentry,
* inodes. So 5 * 2 is 10, plus 1 for the new link, so 11 total items
* should cover the worst case number of items we'll modify.
*/
- trans = btrfs_start_transaction(root, 20);
+ trans = btrfs_start_transaction(root, 11);
if (IS_ERR(trans)) {
ret = PTR_ERR(trans);
goto out_notrans;
diff --git a/fs/btrfs/ordered-data.c b/fs/btrfs/ordered-data.c
index dc08d77b717e..005c45db699e 100644
--- a/fs/btrfs/ordered-data.c
+++ b/fs/btrfs/ordered-data.c
@@ -557,6 +557,7 @@ void btrfs_wait_ordered_extents(struct btrfs_root *root, int delay_iput)
INIT_LIST_HEAD(&splice);
INIT_LIST_HEAD(&works);
+ mutex_lock(&root->fs_info->ordered_operations_mutex);
spin_lock(&root->fs_info->ordered_extent_lock);
list_splice_init(&root->fs_info->ordered_extents, &splice);
while (!list_empty(&splice)) {
@@ -600,6 +601,7 @@ void btrfs_wait_ordered_extents(struct btrfs_root *root, int delay_iput)
cond_resched();
}
+ mutex_unlock(&root->fs_info->ordered_operations_mutex);
}
/*
diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c
index 5471e47d6559..b44124dd2370 100644
--- a/fs/btrfs/qgroup.c
+++ b/fs/btrfs/qgroup.c
@@ -1153,7 +1153,7 @@ int btrfs_qgroup_account_ref(struct btrfs_trans_handle *trans,
ret = btrfs_find_all_roots(trans, fs_info, node->bytenr,
sgn > 0 ? node->seq - 1 : node->seq, &roots);
if (ret < 0)
- goto out;
+ return ret;
spin_lock(&fs_info->qgroup_lock);
quota_root = fs_info->quota_root;
@@ -1275,7 +1275,6 @@ int btrfs_qgroup_account_ref(struct btrfs_trans_handle *trans,
ret = 0;
unlock:
spin_unlock(&fs_info->qgroup_lock);
-out:
ulist_free(roots);
ulist_free(tmp);
diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c
index 53c3501fa4ca..85e072b956d5 100644
--- a/fs/btrfs/scrub.c
+++ b/fs/btrfs/scrub.c
@@ -542,7 +542,6 @@ static void scrub_print_warning(const char *errstr, struct scrub_block *sblock)
eb = path->nodes[0];
ei = btrfs_item_ptr(eb, path->slots[0], struct btrfs_extent_item);
item_size = btrfs_item_size_nr(eb, path->slots[0]);
- btrfs_release_path(path);
if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
do {
@@ -558,7 +557,9 @@ static void scrub_print_warning(const char *errstr, struct scrub_block *sblock)
ret < 0 ? -1 : ref_level,
ret < 0 ? -1 : ref_root);
} while (ret != 1);
+ btrfs_release_path(path);
} else {
+ btrfs_release_path(path);
swarn.path = path;
swarn.dev = dev;
iterate_extent_inodes(fs_info, found_key.objectid,
diff --git a/fs/btrfs/send.c b/fs/btrfs/send.c
index f7a8b861058b..c85e7c6b4598 100644
--- a/fs/btrfs/send.c
+++ b/fs/btrfs/send.c
@@ -3945,12 +3945,10 @@ static int is_extent_unchanged(struct send_ctx *sctx,
found_key.type != key.type) {
key.offset += right_len;
break;
- } else {
- if (found_key.offset != key.offset + right_len) {
- /* Should really not happen */
- ret = -EIO;
- goto out;
- }
+ }
+ if (found_key.offset != key.offset + right_len) {
+ ret = 0;
+ goto out;
}
key = found_key;
}
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 5989a92236f7..2854c824ab64 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -4935,7 +4935,18 @@ int btrfs_rmap_block(struct btrfs_mapping_tree *map_tree,
em = lookup_extent_mapping(em_tree, chunk_start, 1);
read_unlock(&em_tree->lock);
- BUG_ON(!em || em->start != chunk_start);
+ if (!em) {
+ printk(KERN_ERR "btrfs: couldn't find em for chunk %Lu\n",
+ chunk_start);
+ return -EIO;
+ }
+
+ if (em->start != chunk_start) {
+ printk(KERN_ERR "btrfs: bad chunk start, em=%Lu, wanted=%Lu\n",
+ em->start, chunk_start);
+ free_extent_map(em);
+ return -EIO;
+ }
map = (struct map_lookup *)em->bdev;
length = em->len;