| From: David Sterba <dsterba@suse.com> |
| Date: Wed, 10 Jan 2018 15:13:07 +0100 |
| Subject: btrfs: tree-check: reduce stack consumption in check_dir_item |
| |
| commit e2683fc9d219430f5b78889b50cde7f40efeba7b upstream. |
| |
| I've noticed that the updated item checker stack consumption increased |
| dramatically in 542f5385e20cf97447 ("btrfs: tree-checker: Add checker |
| for dir item") |
| |
| tree-checker.c:check_leaf +552 (176 -> 728) |
| |
| The array is 255 bytes long, dynamic allocation would slow down the |
| sanity checks so it's more reasonable to keep it on-stack. Moving the |
| variable to the scope of use reduces the stack usage again |
| |
| tree-checker.c:check_leaf -264 (728 -> 464) |
| |
| Reviewed-by: Josef Bacik <jbacik@fb.com> |
| Reviewed-by: Qu Wenruo <wqu@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> |
| Signed-off-by: Ben Hutchings <ben@decadent.org.uk> |
| --- |
| fs/btrfs/tree-checker.c | 3 ++- |
| 1 file changed, 2 insertions(+), 1 deletion(-) |
| |
| --- a/fs/btrfs/tree-checker.c |
| +++ b/fs/btrfs/tree-checker.c |
| @@ -212,7 +212,6 @@ static int check_dir_item(struct btrfs_r |
| |
| di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item); |
| while (cur < item_size) { |
| - char namebuf[max(BTRFS_NAME_LEN, XATTR_NAME_MAX)]; |
| u32 name_len; |
| u32 data_len; |
| u32 max_name_len; |
| @@ -295,6 +294,8 @@ static int check_dir_item(struct btrfs_r |
| */ |
| if (key->type == BTRFS_DIR_ITEM_KEY || |
| key->type == BTRFS_XATTR_ITEM_KEY) { |
| + char namebuf[max(BTRFS_NAME_LEN, XATTR_NAME_MAX)]; |
| + |
| read_extent_buffer(leaf, namebuf, |
| (unsigned long)(di + 1), name_len); |
| name_hash = btrfs_name_hash(namebuf, name_len); |
