| Message ID | a2ff95d73e0ccec4703c1f4d0b9af4c1a19fe4e2.1443889301.git.zhaolei@cn.fujitsu.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
Hi, On Sun, Oct 04, 2015 at 12:28:39AM +0800, Zhao Lei wrote: > diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c > index 79a5bd9..c05b975 100644 > --- a/fs/btrfs/extent-tree.c > +++ b/fs/btrfs/extent-tree.c > @@ -10010,8 +10010,18 @@ void btrfs_delete_unused_bgs(struct btrfs_fs_info *fs_info) > block_group = list_first_entry(&fs_info->unused_bgs, > struct btrfs_block_group_cache, > bg_list); > - space_info = block_group->space_info; > list_del_init(&block_group->bg_list); > + > + space_info = block_group->space_info; > + > + down_read(&space_info->groups_sem); Thanks for reworking this, are there other patches that I'm missing that are meant to go in before this one? The down_read() this patch adds is inside a spinlock(). -chris -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c index 79a5bd9..c05b975 100644 --- a/fs/btrfs/extent-tree.c +++ b/fs/btrfs/extent-tree.c @@ -10010,8 +10010,18 @@ void btrfs_delete_unused_bgs(struct btrfs_fs_info *fs_info) block_group = list_first_entry(&fs_info->unused_bgs, struct btrfs_block_group_cache, bg_list); - space_info = block_group->space_info; list_del_init(&block_group->bg_list); + + space_info = block_group->space_info; + + down_read(&space_info->groups_sem); + if (list_is_singular(&block_group->list)) { + up_read(&space_info->groups_sem); + btrfs_put_block_group(block_group); + continue; + } + up_read(&space_info->groups_sem); + if (ret || btrfs_mixed_space_info(space_info)) { btrfs_put_block_group(block_group); continue;
Reproduce: (In integration-4.3 branch) TEST_DEV=(/dev/vdg /dev/vdh) TEST_DIR=/mnt/tmp umount "$TEST_DEV" >/dev/null mkfs.btrfs -f -d raid1 "${TEST_DEV[@]}" mount -o nospace_cache "$TEST_DEV" "$TEST_DIR" umount "$TEST_DEV" mount -o nospace_cache "$TEST_DEV" "$TEST_DIR" btrfs filesystem usage $TEST_DIR We can see the data chunk changed from raid1 to single: # btrfs filesystem usage $TEST_DIR Data,single: Size:8.00MiB, Used:0.00B /dev/vdg 8.00MiB # Reason: When a empty filesystem mount with -o nospace_cache, the last data blockgroup will be auto-removed in umount. Then if we mount it again, there is no data chunk in the filesystem, so the only available data profile is 0x0, result is all new chunks are created as single type. Fix: Don't auto-delete last blockgroup for a raid type. Test: Test by above script, and confirmed the logic by debug output. Changelog v2->v3: 1: Use list_is_singular() instead of block_group->list.next == block_group->list.prev Suggested-by: Jeff Mahoney <jeffm@suse.com> Changelog v1->v2: 1: Put code of checking block_group->list into semaphore of space_info->groups_sem. Noticed-by: Filipe Manana <fdmanana@gmail.com> Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com> --- fs/btrfs/extent-tree.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-)