From patchwork Wed Apr 6 07:13:57 2011 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Xin Zhong X-Patchwork-Id: 689311 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by demeter1.kernel.org (8.14.4/8.14.3) with ESMTP id p3689wGc008706 for ; Wed, 6 Apr 2011 08:09:58 GMT Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754565Ab1DFIJz (ORCPT ); Wed, 6 Apr 2011 04:09:55 -0400 Received: from mga09.intel.com ([134.134.136.24]:40564 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754125Ab1DFIJx (ORCPT ); Wed, 6 Apr 2011 04:09:53 -0400 Received: from orsmga001.jf.intel.com ([10.7.209.18]) by orsmga102.jf.intel.com with ESMTP; 06 Apr 2011 01:09:53 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.63,309,1299484800"; d="scan'208";a="729751015" Received: from zhongxin-desktop.bj.intel.com (HELO localhost.localdomain) ([10.238.154.195]) by orsmga001.jf.intel.com with ESMTP; 06 Apr 2011 01:09:52 -0700 From: "Zhong, Xin" To: linux-btrfs@vger.kernel.org Cc: xin.zhong@intel.com Subject: [PATCH V2] Btrfs: fix subvolume mount by name problem when default mount subvolume is set Date: Wed, 6 Apr 2011 15:13:57 +0800 Message-Id: <1302074037-7206-1-git-send-email-xin.zhong@intel.com> X-Mailer: git-send-email 1.7.0.4 Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org X-Greylist: IP, sender and recipient auto-whitelisted, not delayed by milter-greylist-4.2.6 (demeter1.kernel.org [140.211.167.41]); Wed, 06 Apr 2011 08:09:58 +0000 (UTC) We create two subvolumes (meego_root and meego_home) in btrfs root directory. And set meego_root as default mount subvolume. After we remount btrfs, meego_root is mounted to top directory by default. Then when we try to mount meego_home (subvol=meego_home) to a subdirectory, it failed. The problem is when default mount subvolume is set to meego_root, we search meego_home in meego_root but can not find it. So the solution is to add a new mount option (subvolrootid) to specify subvol id of root and search subvol name in it. For our case, now we can use "-o subvolrootid=0,subvol=meego_home) to mount meego_home. Detail information can be found in meego bugzilla: https://bugs.meego.com/show_bug.cgi?id=15055 Signed-off-by: Zhong, Xin --- fs/btrfs/super.c | 43 ++++++++++++++++++++++++++++++++++--------- 1 files changed, 34 insertions(+), 9 deletions(-) diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c index db0a827..5e7bc51 100644 --- a/fs/btrfs/super.c +++ b/fs/btrfs/super.c @@ -156,7 +156,7 @@ enum { Opt_compress_type, Opt_compress_force, Opt_compress_force_type, Opt_notreelog, Opt_ratio, Opt_flushoncommit, Opt_discard, Opt_space_cache, Opt_clear_cache, Opt_user_subvol_rm_allowed, - Opt_enospc_debug, Opt_err, + Opt_enospc_debug, Opt_subvolrootid, Opt_err, }; static match_table_t tokens = { @@ -186,6 +186,7 @@ static match_table_t tokens = { {Opt_clear_cache, "clear_cache"}, {Opt_user_subvol_rm_allowed, "user_subvol_rm_allowed"}, {Opt_enospc_debug, "enospc_debug"}, + {Opt_subvolrootid, "subvolrootid=%d"}, {Opt_err, NULL}, }; @@ -229,6 +230,7 @@ int btrfs_parse_options(struct btrfs_root *root, char *options) break; case Opt_subvol: case Opt_subvolid: + case Opt_subvolrootid: case Opt_device: /* * These are parsed by btrfs_parse_early_options @@ -385,7 +387,7 @@ out: */ static int btrfs_parse_early_options(const char *options, fmode_t flags, void *holder, char **subvol_name, u64 *subvol_objectid, - struct btrfs_fs_devices **fs_devices) + u64 *subvol_rootid, struct btrfs_fs_devices **fs_devices) { substring_t args[MAX_OPT_ARGS]; char *opts, *orig, *p; @@ -426,6 +428,18 @@ static int btrfs_parse_early_options(const char *options, fmode_t flags, *subvol_objectid = intarg; } break; + case Opt_subvolrootid: + intarg = 0; + error = match_int(&args[0], &intarg); + if (!error) { + /* we want the original fs_tree */ + if (!intarg) + *subvol_rootid = + BTRFS_FS_TREE_OBJECTID; + else + *subvol_rootid = intarg; + } + break; case Opt_device: error = btrfs_scan_one_device(match_strdup(&args[0]), flags, holder, fs_devices); @@ -715,6 +729,7 @@ static int btrfs_get_sb(struct file_system_type *fs_type, int flags, fmode_t mode = FMODE_READ; char *subvol_name = NULL; u64 subvol_objectid = 0; + u64 subvol_rootid = 0; int error = 0; if (!(flags & MS_RDONLY)) @@ -722,7 +737,7 @@ static int btrfs_get_sb(struct file_system_type *fs_type, int flags, error = btrfs_parse_early_options(data, mode, fs_type, &subvol_name, &subvol_objectid, - &fs_devices); + &subvol_rootid, &fs_devices); if (error) return error; @@ -786,15 +801,17 @@ static int btrfs_get_sb(struct file_system_type *fs_type, int flags, s->s_flags |= MS_ACTIVE; } - root = get_default_root(s, subvol_objectid); - if (IS_ERR(root)) { - error = PTR_ERR(root); - deactivate_locked_super(s); - goto error_free_subvol_name; - } /* if they gave us a subvolume name bind mount into that */ if (strcmp(subvol_name, ".")) { struct dentry *new_root; + + root = get_default_root(s, subvol_rootid); + if (IS_ERR(root)) { + error = PTR_ERR(root); + deactivate_locked_super(s); + goto error_free_subvol_name; + } + mutex_lock(&root->d_inode->i_mutex); new_root = lookup_one_len(subvol_name, root, strlen(subvol_name)); @@ -816,6 +833,14 @@ static int btrfs_get_sb(struct file_system_type *fs_type, int flags, dput(root); root = new_root; } + } else { + root = get_default_root(s, subvol_objectid); + if (IS_ERR(root)) { + error = PTR_ERR(root); + deactivate_locked_super(s); + goto error_free_subvol_name; + } + } mnt->mnt_sb = s; mnt->mnt_root = root;