diff options
| author | Liu Bo <bo.li.liu@oracle.com> | 2016-09-23 13:44:44 -0700 |
|---|---|---|
| committer | David Sterba <dsterba@suse.com> | 2016-09-26 19:37:06 +0200 |
| commit | 851cd173f06045816528176001cf82948282029c (patch) | |
| tree | 280bf393ed2e9f10130fd8eea3bc08e3c601d083 /fs/btrfs/extent_io.c | |
| parent | 0f5053eb90f58c619885eac2757ccdc5eccd9046 (diff) | |
| download | lwn-851cd173f06045816528176001cf82948282029c.tar.gz lwn-851cd173f06045816528176001cf82948282029c.zip | |
Btrfs: memset to avoid stale content in btree leaf
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>
Diffstat (limited to 'fs/btrfs/extent_io.c')
| -rw-r--r-- | fs/btrfs/extent_io.c | 18 |
1 files changed, 13 insertions, 5 deletions
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c index 0d1876c76732..ee40384c394d 100644 --- a/fs/btrfs/extent_io.c +++ b/fs/btrfs/extent_io.c @@ -3725,8 +3725,10 @@ static noinline_for_stack int write_one_eb(struct extent_buffer *eb, 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 write_flags = (epd->sync_io ? WRITE_SYNC : 0) | REQ_META; int ret = 0; @@ -3736,15 +3738,21 @@ static noinline_for_stack int write_one_eb(struct extent_buffer *eb, 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++) { |