4.4-stable review patch. If anyone has any objections, please let me know.
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From: Liu Bo bo.li.liu@oracle.com
commit 851cd173f06045816528176001cf82948282029c upstream.
This is an additional patch to "Btrfs: memset to avoid stale content in btree node block".
This uses memset to initialize the unused space in a leaf to avoid potential stale content, which may be incurred by pushing items between sibling leaves.
Signed-off-by: Liu Bo bo.li.liu@oracle.com Reviewed-by: David Sterba dsterba@suse.com Signed-off-by: David Sterba dsterba@suse.com Signed-off-by: Ben Hutchings ben.hutchings@codethink.co.uk Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/btrfs/ctree.c | 14 -------------- fs/btrfs/ctree.h | 15 +++++++++++++++ fs/btrfs/extent_io.c | 18 +++++++++++++----- 3 files changed, 28 insertions(+), 19 deletions(-)
--- a/fs/btrfs/ctree.c +++ b/fs/btrfs/ctree.c @@ -1726,20 +1726,6 @@ int btrfs_realloc_node(struct btrfs_tran return err; }
-/* - * The leaf data grows from end-to-front in the node. - * this returns the address of the start of the last item, - * which is the stop of the leaf data stack - */ -static inline unsigned int leaf_data_end(struct btrfs_root *root, - struct extent_buffer *leaf) -{ - u32 nr = btrfs_header_nritems(leaf); - if (nr == 0) - return BTRFS_LEAF_DATA_SIZE(root); - return btrfs_item_offset_nr(leaf, nr - 1); -} -
/* * search for key in the extent_buffer. The items start at offset p, --- a/fs/btrfs/ctree.h +++ b/fs/btrfs/ctree.h @@ -3158,6 +3158,21 @@ static inline unsigned long btrfs_leaf_d return offsetof(struct btrfs_leaf, items); }
+/* + * The leaf data grows from end-to-front in the node. + * this returns the address of the start of the last item, + * which is the stop of the leaf data stack + */ +static inline unsigned int leaf_data_end(struct btrfs_root *root, + struct extent_buffer *leaf) +{ + u32 nr = btrfs_header_nritems(leaf); + + if (nr == 0) + return BTRFS_LEAF_DATA_SIZE(root); + return btrfs_item_offset_nr(leaf, nr - 1); +} + /* struct btrfs_file_extent_item */ BTRFS_SETGET_FUNCS(file_extent_type, struct btrfs_file_extent_item, type, 8); BTRFS_SETGET_STACK_FUNCS(stack_file_extent_disk_bytenr, --- a/fs/btrfs/extent_io.c +++ b/fs/btrfs/extent_io.c @@ -3847,8 +3847,10 @@ static noinline_for_stack int write_one_ struct block_device *bdev = fs_info->fs_devices->latest_bdev; struct extent_io_tree *tree = &BTRFS_I(fs_info->btree_inode)->io_tree; u64 offset = eb->start; + u32 nritems; unsigned long i, num_pages; unsigned long bio_flags = 0; + unsigned long start, end; int rw = (epd->sync_io ? WRITE_SYNC : WRITE) | REQ_META; int ret = 0;
@@ -3858,15 +3860,21 @@ static noinline_for_stack int write_one_ if (btrfs_header_owner(eb) == BTRFS_TREE_LOG_OBJECTID) bio_flags = EXTENT_BIO_TREE_LOG;
- /* set btree node beyond nritems with 0 to avoid stale content */ + /* set btree blocks beyond nritems with 0 to avoid stale content. */ + nritems = btrfs_header_nritems(eb); if (btrfs_header_level(eb) > 0) { - u32 nritems; - unsigned long end; - - nritems = btrfs_header_nritems(eb); end = btrfs_node_key_ptr_offset(nritems);
memset_extent_buffer(eb, 0, end, eb->len - end); + } else { + /* + * leaf: + * header 0 1 2 .. N ... data_N .. data_2 data_1 data_0 + */ + start = btrfs_item_nr_offset(nritems); + end = btrfs_leaf_data(eb) + + leaf_data_end(fs_info->tree_root, eb); + memset_extent_buffer(eb, 0, start, end - start); }
for (i = 0; i < num_pages; i++) {