| Message ID | cb4fecfa-9b40-d42c-8218-f0e7f7ac7fbb@suse.com (mailing list archive) |
|---|---|
| State | Accepted |
| Headers | show |
At 08/16/2016 12:10 AM, Jeff Mahoney wrote: > The qgroup_flags field is overloaded such that it reflects the on-disk > status of qgroups and the runtime state. The BTRFS_QGROUP_STATUS_FLAG_RESCAN > flag is used to indicate that a rescan operation is in progress, but if > the file system is unmounted while a rescan is running, the rescan > operation is paused. If the file system is then mounted read-only, > the flag will still be present but the rescan operation will not have > been resumed. When we go to umount, btrfs_qgroup_wait_for_completion > will see the flag and interpret it to mean that the rescan worker is > still running and will wait for a completion that will never come. > > This patch uses a separate flag to indicate when the worker is > running. The locking and state surrounding the qgroup rescan worker > needs a lot of attention beyond this patch but this is enough to > avoid a hung umount. > > Cc: <stable@vger.kernel.org> # v4.4+ > Signed-off-by; Jeff Mahoney <jeffm@suse.com> Reviewed-by: Qu Wenruo <quwenruo@cn.fujitsu.com> Looks good to me. Would you mind to submit a test case for it? Thanks, Qu > --- > fs/btrfs/ctree.h | 1 + > fs/btrfs/disk-io.c | 1 + > fs/btrfs/qgroup.c | 9 ++++++++- > 3 files changed, 10 insertions(+), 1 deletion(-) > > --- a/fs/btrfs/ctree.h > +++ b/fs/btrfs/ctree.h > @@ -1771,6 +1771,7 @@ struct btrfs_fs_info { > struct btrfs_workqueue *qgroup_rescan_workers; > struct completion qgroup_rescan_completion; > struct btrfs_work qgroup_rescan_work; > + bool qgroup_rescan_running; /* protected by qgroup_rescan_lock */ > > /* filesystem state */ > unsigned long fs_state; > --- a/fs/btrfs/disk-io.c > +++ b/fs/btrfs/disk-io.c > @@ -2275,6 +2275,7 @@ static void btrfs_init_qgroup(struct btr > fs_info->quota_enabled = 0; > fs_info->pending_quota_state = 0; > fs_info->qgroup_ulist = NULL; > + fs_info->qgroup_rescan_running = false; > mutex_init(&fs_info->qgroup_rescan_lock); > } > > --- a/fs/btrfs/qgroup.c > +++ b/fs/btrfs/qgroup.c > @@ -2302,6 +2302,10 @@ static void btrfs_qgroup_rescan_worker(s > int err = -ENOMEM; > int ret = 0; > > + mutex_lock(&fs_info->qgroup_rescan_lock); > + fs_info->qgroup_rescan_running = true; > + mutex_unlock(&fs_info->qgroup_rescan_lock); > + > path = btrfs_alloc_path(); > if (!path) > goto out; > @@ -2368,6 +2372,9 @@ out: > } > > done: > + mutex_lock(&fs_info->qgroup_rescan_lock); > + fs_info->qgroup_rescan_running = false; > + mutex_unlock(&fs_info->qgroup_rescan_lock); > complete_all(&fs_info->qgroup_rescan_completion); > } > > @@ -2494,7 +2501,7 @@ int btrfs_qgroup_wait_for_completion(str > > mutex_lock(&fs_info->qgroup_rescan_lock); > spin_lock(&fs_info->qgroup_lock); > - running = fs_info->qgroup_flags & BTRFS_QGROUP_STATUS_FLAG_RESCAN; > + running = fs_info->qgroup_rescan_running; > spin_unlock(&fs_info->qgroup_lock); > mutex_unlock(&fs_info->qgroup_rescan_lock); > > -- 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
--- a/fs/btrfs/ctree.h +++ b/fs/btrfs/ctree.h @@ -1771,6 +1771,7 @@ struct btrfs_fs_info { struct btrfs_workqueue *qgroup_rescan_workers; struct completion qgroup_rescan_completion; struct btrfs_work qgroup_rescan_work; + bool qgroup_rescan_running; /* protected by qgroup_rescan_lock */ /* filesystem state */ unsigned long fs_state; --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -2275,6 +2275,7 @@ static void btrfs_init_qgroup(struct btr fs_info->quota_enabled = 0; fs_info->pending_quota_state = 0; fs_info->qgroup_ulist = NULL; + fs_info->qgroup_rescan_running = false; mutex_init(&fs_info->qgroup_rescan_lock); } --- a/fs/btrfs/qgroup.c +++ b/fs/btrfs/qgroup.c @@ -2302,6 +2302,10 @@ static void btrfs_qgroup_rescan_worker(s int err = -ENOMEM; int ret = 0; + mutex_lock(&fs_info->qgroup_rescan_lock); + fs_info->qgroup_rescan_running = true; + mutex_unlock(&fs_info->qgroup_rescan_lock); + path = btrfs_alloc_path(); if (!path) goto out; @@ -2368,6 +2372,9 @@ out: } done: + mutex_lock(&fs_info->qgroup_rescan_lock); + fs_info->qgroup_rescan_running = false; + mutex_unlock(&fs_info->qgroup_rescan_lock); complete_all(&fs_info->qgroup_rescan_completion); } @@ -2494,7 +2501,7 @@ int btrfs_qgroup_wait_for_completion(str mutex_lock(&fs_info->qgroup_rescan_lock); spin_lock(&fs_info->qgroup_lock); - running = fs_info->qgroup_flags & BTRFS_QGROUP_STATUS_FLAG_RESCAN; + running = fs_info->qgroup_rescan_running; spin_unlock(&fs_info->qgroup_lock); mutex_unlock(&fs_info->qgroup_rescan_lock);