From patchwork Sat Nov 5 17:26:34 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jeff Mahoney X-Patchwork-Id: 9413775 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id E68A260573 for ; Sat, 5 Nov 2016 17:26:50 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id D26F5293BF for ; Sat, 5 Nov 2016 17:26:50 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id C51A329410; Sat, 5 Nov 2016 17:26:50 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 3542B293BF for ; Sat, 5 Nov 2016 17:26:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754700AbcKER0m (ORCPT ); Sat, 5 Nov 2016 13:26:42 -0400 Received: from mx2.suse.de ([195.135.220.15]:59003 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751438AbcKER0m (ORCPT ); Sat, 5 Nov 2016 13:26:42 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (charybdis-ext.suse.de [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id 698DFACE6 for ; Sat, 5 Nov 2016 17:26:40 +0000 (UTC) Received: by starscream.home.jeffm.io (Postfix, from userid 1000) id 2C70085549; Sat, 5 Nov 2016 13:26:37 -0400 (EDT) From: jeffm@suse.com To: linux-btrfs@vger.kernel.org Cc: Jeff Mahoney Subject: [PATCH 1/2] btrfs: remove old tree_root dirent processing in btrfs_real_readdir() Date: Sat, 5 Nov 2016 13:26:34 -0400 Message-Id: <1478366795-27009-1-git-send-email-jeffm@suse.com> X-Mailer: git-send-email 2.7.1 Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Jeff Mahoney Commit 3de4586c527 (Btrfs: Allow subvolumes and snapshots anywhere in the directory tree) introduced the current system of placing snapshots in the directory tree. It also introduced the behavior of creating the snapshot and then creating the directory entries for it. We've kept this code around for compatibility reasons, but it turns out that no file systems with the old tree_root based snapshots can be mounted on newer (>= 2009) kernels anyway. About a month after the above commit, commit 2a7108ad89e (Btrfs: rev the disk format for the inode compat and csum selection changes) landed, changing the superblock magic number. As a result, we know that we'll never encounter tree_root-based dirents or have to deal with skipping our own snapshot dirents. Since that also means that we're now only iterating over DIR_INDEX items, which only contain one directory entry per leaf item, we don't need to loop over the leaf item contents anymore either. Signed-off-by: Jeff Mahoney Reviewed-by: David Sterba --- fs/btrfs/inode.c | 118 +++++++++++++++++-------------------------------------- 1 file changed, 37 insertions(+), 81 deletions(-) diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index 2b790bd..c52239d 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -5805,20 +5805,13 @@ static int btrfs_real_readdir(struct file *file, struct dir_context *ctx) int slot; unsigned char d_type; int over = 0; - u32 di_cur; - u32 di_total; - u32 di_len; - int key_type = BTRFS_DIR_INDEX_KEY; char tmp_name[32]; char *name_ptr; int name_len; int is_curr = 0; /* ctx->pos points to the current index? */ bool emitted; bool put = false; - - /* FIXME, use a real flag for deciding about the key type */ - if (root->fs_info->tree_root == root) - key_type = BTRFS_DIR_ITEM_KEY; + struct btrfs_key location; if (!dir_emit_dots(file, ctx)) return 0; @@ -5829,14 +5822,11 @@ static int btrfs_real_readdir(struct file *file, struct dir_context *ctx) path->reada = READA_FORWARD; - if (key_type == BTRFS_DIR_INDEX_KEY) { - INIT_LIST_HEAD(&ins_list); - INIT_LIST_HEAD(&del_list); - put = btrfs_readdir_get_delayed_items(inode, &ins_list, - &del_list); - } + INIT_LIST_HEAD(&ins_list); + INIT_LIST_HEAD(&del_list); + put = btrfs_readdir_get_delayed_items(inode, &ins_list, &del_list); - key.type = key_type; + key.type = BTRFS_DIR_INDEX_KEY; key.offset = ctx->pos; key.objectid = btrfs_ino(inode); @@ -5862,85 +5852,53 @@ static int btrfs_real_readdir(struct file *file, struct dir_context *ctx) if (found_key.objectid != key.objectid) break; - if (found_key.type != key_type) + if (found_key.type != BTRFS_DIR_INDEX_KEY) break; if (found_key.offset < ctx->pos) goto next; - if (key_type == BTRFS_DIR_INDEX_KEY && - btrfs_should_delete_dir_index(&del_list, - found_key.offset)) + if (btrfs_should_delete_dir_index(&del_list, found_key.offset)) goto next; ctx->pos = found_key.offset; is_curr = 1; di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item); - di_cur = 0; - di_total = btrfs_item_size(leaf, item); - - while (di_cur < di_total) { - struct btrfs_key location; - - if (verify_dir_item(root, leaf, di)) - break; + if (verify_dir_item(root, leaf, di)) + goto next; - name_len = btrfs_dir_name_len(leaf, di); - if (name_len <= sizeof(tmp_name)) { - name_ptr = tmp_name; - } else { - name_ptr = kmalloc(name_len, GFP_KERNEL); - if (!name_ptr) { - ret = -ENOMEM; - goto err; - } + name_len = btrfs_dir_name_len(leaf, di); + if (name_len <= sizeof(tmp_name)) { + name_ptr = tmp_name; + } else { + name_ptr = kmalloc(name_len, GFP_KERNEL); + if (!name_ptr) { + ret = -ENOMEM; + goto err; } - read_extent_buffer(leaf, name_ptr, - (unsigned long)(di + 1), name_len); - - d_type = btrfs_filetype_table[btrfs_dir_type(leaf, di)]; - btrfs_dir_item_key_to_cpu(leaf, di, &location); + } + read_extent_buffer(leaf, name_ptr, (unsigned long)(di + 1), + name_len); + d_type = btrfs_filetype_table[btrfs_dir_type(leaf, di)]; + btrfs_dir_item_key_to_cpu(leaf, di, &location); - /* is this a reference to our own snapshot? If so - * skip it. - * - * In contrast to old kernels, we insert the snapshot's - * dir item and dir index after it has been created, so - * we won't find a reference to our own snapshot. We - * still keep the following code for backward - * compatibility. - */ - if (location.type == BTRFS_ROOT_ITEM_KEY && - location.objectid == root->root_key.objectid) { - over = 0; - goto skip; - } - over = !dir_emit(ctx, name_ptr, name_len, - location.objectid, d_type); + over = !dir_emit(ctx, name_ptr, name_len, location.objectid, + d_type); -skip: - if (name_ptr != tmp_name) - kfree(name_ptr); + if (name_ptr != tmp_name) + kfree(name_ptr); - if (over) - goto nopos; - emitted = true; - di_len = btrfs_dir_name_len(leaf, di) + - btrfs_dir_data_len(leaf, di) + sizeof(*di); - di_cur += di_len; - di = (struct btrfs_dir_item *)((char *)di + di_len); - } + if (over) + goto nopos; next: path->slots[0]++; } - if (key_type == BTRFS_DIR_INDEX_KEY) { - if (is_curr) - ctx->pos++; - ret = btrfs_readdir_delayed_dir_index(ctx, &ins_list, &emitted); - if (ret) - goto nopos; - } + if (is_curr) + ctx->pos++; + ret = btrfs_readdir_delayed_dir_index(ctx, &ins_list, &emitted); + if (ret) + goto nopos; /* * If we haven't emitted any dir entry, we must not touch ctx->pos as @@ -5971,12 +5929,10 @@ static int btrfs_real_readdir(struct file *file, struct dir_context *ctx) * last entry requires it because doing so has broken 32bit apps * in the past. */ - if (key_type == BTRFS_DIR_INDEX_KEY) { - if (ctx->pos >= INT_MAX) - ctx->pos = LLONG_MAX; - else - ctx->pos = INT_MAX; - } + if (ctx->pos >= INT_MAX) + ctx->pos = LLONG_MAX; + else + ctx->pos = INT_MAX; nopos: ret = 0; err: