Btrfs: fix possible ENOSPC problems with truncate
There's a problem where we don't do any space reservation for truncates, which
can cause you to OOPs because you will be allowed to go off in the weeds a bit
since we don't account for the delalloc bytes that are created as a result of
the truncate.
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 5b9567c..78139ef 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -3032,12 +3032,22 @@
if ((offset & (blocksize - 1)) == 0)
goto out;
+ ret = btrfs_check_data_free_space(root, inode, PAGE_CACHE_SIZE);
+ if (ret)
+ goto out;
+
+ ret = btrfs_reserve_metadata_for_delalloc(root, inode, 1);
+ if (ret)
+ goto out;
ret = -ENOMEM;
again:
page = grab_cache_page(mapping, index);
- if (!page)
+ if (!page) {
+ btrfs_free_reserved_data_space(root, inode, PAGE_CACHE_SIZE);
+ btrfs_unreserve_metadata_for_delalloc(root, inode, 1);
goto out;
+ }
page_start = page_offset(page);
page_end = page_start + PAGE_CACHE_SIZE - 1;
@@ -3070,6 +3080,10 @@
goto again;
}
+ clear_extent_bits(&BTRFS_I(inode)->io_tree, page_start, page_end,
+ EXTENT_DIRTY | EXTENT_DELALLOC | EXTENT_DO_ACCOUNTING,
+ GFP_NOFS);
+
ret = btrfs_set_extent_delalloc(inode, page_start, page_end);
if (ret) {
unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
@@ -3088,6 +3102,9 @@
unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
out_unlock:
+ if (ret)
+ btrfs_free_reserved_data_space(root, inode, PAGE_CACHE_SIZE);
+ btrfs_unreserve_metadata_for_delalloc(root, inode, 1);
unlock_page(page);
page_cache_release(page);
out:
@@ -3111,7 +3128,9 @@
if (size <= hole_start)
return 0;
- btrfs_truncate_page(inode->i_mapping, inode->i_size);
+ err = btrfs_truncate_page(inode->i_mapping, inode->i_size);
+ if (err)
+ return err;
while (1) {
struct btrfs_ordered_extent *ordered;
@@ -5008,7 +5027,9 @@
if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
return;
- btrfs_truncate_page(inode->i_mapping, inode->i_size);
+ ret = btrfs_truncate_page(inode->i_mapping, inode->i_size);
+ if (ret)
+ return;
btrfs_wait_ordered_range(inode, inode->i_size & (~mask), (u64)-1);
trans = btrfs_start_transaction(root, 1);