Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs

Pull more btrfs updates from Chris Mason:
 "This has a few fixes since our last pull and a new ioctl for doing
  btree searches from userland.  It's very similar to the existing
  ioctl, but lets us return larger items back down to the app"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs:
  btrfs: fix error handling in create_pending_snapshot
  btrfs: fix use of uninit "ret" in end_extent_writepage()
  btrfs: free ulist in qgroup_shared_accounting() error path
  Btrfs: fix qgroups sanity test crash or hang
  btrfs: prevent RCU warning when dereferencing radix tree slot
  Btrfs: fix unfinished readahead thread for raid5/6 degraded mounting
  btrfs: new ioctl TREE_SEARCH_V2
  btrfs: tree_search, search_ioctl: direct copy to userspace
  btrfs: new function read_extent_buffer_to_user
  btrfs: tree_search, copy_to_sk: return needed size on EOVERFLOW
  btrfs: tree_search, copy_to_sk: return EOVERFLOW for too small buffer
  btrfs: tree_search, search_ioctl: accept varying buffer
  btrfs: tree_search: eliminate redundant nr_items check

1 files changed, 38 insertions, 1 deletions

diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index f25a909..a389820 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -2354,7 +2354,7 @@ int end_extent_writepage(struct page *page, int err, u64 start, u64 end)
 {
 	int uptodate = (err == 0);
 	struct extent_io_tree *tree;
-	int ret;
+	int ret = 0;
 
 	tree = &BTRFS_I(page->mapping->host)->io_tree;
 
@@ -5068,6 +5068,43 @@ void read_extent_buffer(struct extent_buffer *eb, void *dstv,
 	}
 }
 
+int read_extent_buffer_to_user(struct extent_buffer *eb, void __user *dstv,
+			unsigned long start,
+			unsigned long len)
+{
+	size_t cur;
+	size_t offset;
+	struct page *page;
+	char *kaddr;
+	char __user *dst = (char __user *)dstv;
+	size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1);
+	unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT;
+	int ret = 0;
+
+	WARN_ON(start > eb->len);
+	WARN_ON(start + len > eb->start + eb->len);
+
+	offset = (start_offset + start) & (PAGE_CACHE_SIZE - 1);
+
+	while (len > 0) {
+		page = extent_buffer_page(eb, i);
+
+		cur = min(len, (PAGE_CACHE_SIZE - offset));
+		kaddr = page_address(page);
+		if (copy_to_user(dst, kaddr + offset, cur)) {
+			ret = -EFAULT;
+			break;
+		}
+
+		dst += cur;
+		len -= cur;
+		offset = 0;
+		i++;
+	}
+
+	return ret;
+}
+
 int map_private_extent_buffer(struct extent_buffer *eb, unsigned long start,
 			       unsigned long min_len, char **map,
 			       unsigned long *map_start,