From mboxrd@z Thu Jan 1 00:00:00 1970 From: Arne Jansen Subject: Re: [PATCH 1/2] Btrfs: fix OOPS of empty filesystem after balance Date: Wed, 30 Mar 2011 13:58:50 +0200 Message-ID: <4D931AFA.1050004@gmx.net> References: <4D743F3A.6030105@cn.fujitsu.com> <4D7890D3.6080309@cn.fujitsu.com> <1299760026-sup-300@think> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Cc: liubo , Linux Btrfs , slyich@gmail.com To: Chris Mason Return-path: In-Reply-To: <1299760026-sup-300@think> List-ID: Am 10.03.2011 13:28, schrieb Chris Mason: > Excerpts from liubo's message of 2011-03-10 03:50:27 -0500: >> On 03/07/2011 10:13 AM, liubo wrote: >>> btrfs will remove unused block groups after balance. >>> When a empty filesystem is balanced, the block group with tag "DATA" may be >>> dropped, and after umount and mount again, it will not find "DATA" space_info >>> and lead to OOPS. >>> So we initial the necessary space_infos(DATA, SYSTEM, METADATA) to avoid OOPS. >>> this patch breaks mixed block groups. If the space_infos get added upfront, later on all mixed block groups will be added to the data space_info, leaving the metadata space_info completely empty. No mixed space_info will ever get created. As a fix it might be enough to call btrfs_init_space_info after btrfs_read_block_groups, not before, but I haven't tested it. This was the cause of the BUG reported by Sergei Trofimovich in the thread "v2.6.38-6555-ga44f99c: null pointer dereference on -ENOSPC". -Arne >> >> Hi, Chirs, >> >> These two fixes are for critical problems(one OOPS and one memory leak), so would >> you please take some time to review them and check if they are ready for the next >> git pull? >> >> Seems that you have been a lot busy these days. ;) > > Hi Liubo, > > I'm looking at both of these. There are no more rc's for 2.6.38, only > the final release, so the bar is very high for a commit that goes in. > > -chris > >> >> thanks, >> liubo >> >>> Reported-by: Daniel J Blueman >>> Signed-off-by: Liu Bo >>> --- >>> fs/btrfs/ctree.h | 1 + >>> fs/btrfs/disk-io.c | 6 ++++++ >>> fs/btrfs/extent-tree.c | 23 +++++++++++++++++++++++ >>> 3 files changed, 30 insertions(+), 0 deletions(-) >>> >>> diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h >>> index 28188a7..49c50e5 100644 >>> --- a/fs/btrfs/ctree.h >>> +++ b/fs/btrfs/ctree.h >>> @@ -2221,6 +2221,7 @@ int btrfs_error_discard_extent(struct btrfs_root *root, u64 bytenr, >>> u64 num_bytes); >>> int btrfs_force_chunk_alloc(struct btrfs_trans_handle *trans, >>> struct btrfs_root *root, u64 type); >>> +int btrfs_init_space_info(struct btrfs_fs_info *fs_info); >>> >>> /* ctree.c */ >>> int btrfs_bin_search(struct extent_buffer *eb, struct btrfs_key *key, >>> diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c >>> index 3e1ea3e..8bcdc62 100644 >>> --- a/fs/btrfs/disk-io.c >>> +++ b/fs/btrfs/disk-io.c >>> @@ -1967,6 +1967,12 @@ struct btrfs_root *open_ctree(struct super_block *sb, >>> fs_info->metadata_alloc_profile = (u64)-1; >>> fs_info->system_alloc_profile = fs_info->metadata_alloc_profile; >>> >>> + ret = btrfs_init_space_info(fs_info); >>> + if (ret) { >>> + printk(KERN_ERR "Failed to initial space info: %d\n", ret); >>> + goto fail_block_groups; >>> + } >>> + >>> ret = btrfs_read_block_groups(extent_root); >>> if (ret) { >>> printk(KERN_ERR "Failed to read block groups: %d\n", ret); >>> diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c >>> index 100e409..08525ee 100644 >>> --- a/fs/btrfs/extent-tree.c >>> +++ b/fs/btrfs/extent-tree.c >>> @@ -8714,6 +8714,29 @@ out: >>> return ret; >>> } >>> >>> +int btrfs_init_space_info(struct btrfs_fs_info *fs_info) >>> +{ >>> + struct btrfs_space_info *space_info; >>> + int ret; >>> + >>> + ret = update_space_info(fs_info, BTRFS_BLOCK_GROUP_SYSTEM, 0, 0, >>> + &space_info); >>> + if (ret) >>> + return ret; >>> + >>> + ret = update_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA, 0, 0, >>> + &space_info); >>> + if (ret) >>> + return ret; >>> + >>> + ret = update_space_info(fs_info, BTRFS_BLOCK_GROUP_DATA, 0, 0, >>> + &space_info); >>> + if (ret) >>> + return ret; >>> + >>> + return ret; >>> +} >>> + >>> int btrfs_error_unpin_extent_range(struct btrfs_root *root, u64 start, u64 end) >>> { >>> return unpin_extent_range(root, start, end); >>