From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp206.alice.it ([82.57.200.102]:37269 "EHLO smtp206.alice.it" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759495Ab2HXN7H (ORCPT ); Fri, 24 Aug 2012 09:59:07 -0400 Received: from venice.bhome (151.24.44.165) by smtp206.alice.it (8.6.023.02) (authenticated as kreijack@alice.it) id 500F3F95054669C2 for linux-btrfs@vger.kernel.org; Fri, 24 Aug 2012 15:59:06 +0200 Subject: [PATCH v1 4/4] Btrfs sysfs support documentation. To: linux-btrfs@vger.kernel.org From: Goffredo Baroncelli Date: Fri, 24 Aug 2012 15:59:50 +0200 Message-ID: <20120824135935.20478.6629.stgit@venice.bhome> In-Reply-To: <20120824135322.20478.88578.stgit@venice.bhome> References: <20120824135322.20478.88578.stgit@venice.bhome> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Sender: linux-btrfs-owner@vger.kernel.org List-ID: Update of the Documentation/filesystes/btrfs.txt file. Signed-off-by: Goffredo Baroncelli --- 0 files changed diff --git a/Documentation/filesystems/btrfs.txt b/Documentation/filesystems/btrfs.txt index 7671352..35840ab 100644 --- a/Documentation/filesystems/btrfs.txt +++ b/Documentation/filesystems/btrfs.txt @@ -89,3 +89,78 @@ btrfsck: do a limited check of the FS extent trees. btrfs-debug-tree: print all of the FS metadata in text form. Example: btrfs-debug-tree /dev/sda2 >& big_output_file + + + + SYSFS SUPPORT + ============= + +If the option CONFIG_BTRFS_FS_SYSFS is enabled, BTRFS exports some +information via the sysfs filesystem. +Todate these information are read-only. + +The information exported are related to both the devices and the filesystems. +When a devices is registred (for example via the btrfs filesystem scan +command), BTRFS creates the following entries under /sys/fs/btrfs: + +/sys/fs/btrfs: + + - devices -> information per device basis + - filesystem -> information per filesystem basis + +/sys/fs/btrfs/devices/: + + - bytes_used + - devid + - disk_total_bytes + - fsid -> fielsystem UUID + - generation + - major [*] + - minor [*] + - missing + - name -> device name (eg: /dev/sda) + - total_bytes + - write_errors -> error info + - corruption_errors -> error info + - read_errors -> error info + - generation_errors -> error info + - flush_errors -> error info + - writeable + +[*] These information are available only after the mounting of the +filesystem. + +/sys/fs/btrfs/filesystem//fs_info: + + - balance_cancel_req -> balance status information + - balance_pause_req -> balance status information + - balance_running -> balance status information + - fs_state + - generation + - label -> label of the filesystem + - last_trans_committed + - scrub_cancel_req -> scrub status information + - scrub_pause_req -> scrub status information + - scrubs_paused -> scrub status information + - scrubs_running -> scrub status information + +/sys/fs/btrfs/filesystem//fs_devices: + + - latest_devid + - latest_trans + - missing_devices + - num_can_discard + - open_devices + - opened + - rw_devices + - seeding + - total_rw_bytes + +The filesystems information are split in two section (fs_info and fs_devices) +because the fs_devices entries are available after the scan of the device(s), +but the fs_info entries are available only after the mount of the +filesystem. + +The link between the filesystem and the device(s) is the fsid == +filesystem-UUID. +