From: Aleksa Sarai Date: Tue, 4 Jul 2017 11:49:06 +0000 (+1000) Subject: btrfs: resume qgroup rescan on rw remount X-Git-Tag: v4.9.50~11 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=0f7dbc4d5bc88432ab1c8639c66628d4f5903ae9;p=platform%2Fkernel%2Flinux-amlogic.git btrfs: resume qgroup rescan on rw remount commit 6c6b5a39c4bf3dbd8cf629c9f5450e983c19dbb9 upstream. Several distributions mount the "proper root" as ro during initrd and then remount it as rw before pivot_root(2). Thus, if a rescan had been aborted by a previous shutdown, the rescan would never be resumed. This issue would manifest itself as several btrfs ioctl(2)s causing the entire machine to hang when btrfs_qgroup_wait_for_completion was hit (due to the fs_info->qgroup_rescan_running flag being set but the rescan itself not being resumed). Notably, Docker's btrfs storage driver makes regular use of BTRFS_QUOTA_CTL_DISABLE and BTRFS_IOC_QUOTA_RESCAN_WAIT (causing this problem to be manifested on boot for some machines). Cc: Jeff Mahoney Fixes: b382a324b60f ("Btrfs: fix qgroup rescan resume on mount") Signed-off-by: Aleksa Sarai Reviewed-by: Nikolay Borisov Tested-by: Nikolay Borisov Signed-off-by: David Sterba Signed-off-by: Greg Kroah-Hartman --- diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c index 74ed5aae6cea..f6e111984ce2 100644 --- a/fs/btrfs/super.c +++ b/fs/btrfs/super.c @@ -1834,6 +1834,8 @@ static int btrfs_remount(struct super_block *sb, int *flags, char *data) goto restore; } + btrfs_qgroup_rescan_resume(fs_info); + if (!fs_info->uuid_root) { btrfs_info(fs_info, "creating UUID tree"); ret = btrfs_create_uuid_tree(fs_info);