btrfs: waiting on qgroup rescan should not always be interruptible

commit d06f23d6a947c9abae41dc46be69a56baf36f436 upstream.

We wait on qgroup rescan completion in three places: file system
shutdown, the quota disable ioctl, and the rescan wait ioctl.  If the
user sends a signal while we're waiting, we continue happily along.  This
is expected behavior for the rescan wait ioctl.  It's racy in the shutdown
path but mostly works due to other unrelated synchronization points.
In the quota disable path, it Oopses the kernel pretty much immediately.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 41fb43183406c944086ca6eefaf10c7f5a35880e..10bc556ddb3de3a07e86e02e32f316fb252075a6 100644 (file)
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -3811,7 +3811,7 @@ void close_ctree(struct btrfs_root *root)
        smp_mb();
 
        /* wait for the qgroup rescan worker to stop */
-       btrfs_qgroup_wait_for_completion(fs_info);
+       btrfs_qgroup_wait_for_completion(fs_info, false);
 
        /* wait for the uuid_scan task to finish */
        down(&fs_info->uuid_tree_rescan_sem);

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index bfcd87ee8ff543ad6da1d2c8a9da903ef0ad3758..65f30b3b04f91d54fc1bd9def4440d72fa077189 100644 (file)
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -5121,7 +5121,7 @@ static long btrfs_ioctl_quota_rescan_wait(struct file *file, void __user *arg)
        if (!capable(CAP_SYS_ADMIN))
                return -EPERM;
 
-       return btrfs_qgroup_wait_for_completion(root->fs_info);
+       return btrfs_qgroup_wait_for_completion(root->fs_info, true);
 }
 
 static long _btrfs_ioctl_set_received_subvol(struct file *file,

diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c
index 5279fdae7142fbe3177a556a020ed1af3a7aa8f1..d7829f5ebaf57dca099ed05e74bb959694ac9a21 100644 (file)
--- a/fs/btrfs/qgroup.c
+++ b/fs/btrfs/qgroup.c
@@ -995,7 +995,7 @@ int btrfs_quota_disable(struct btrfs_trans_handle *trans,
                goto out;
        fs_info->quota_enabled = 0;
        fs_info->pending_quota_state = 0;
-       btrfs_qgroup_wait_for_completion(fs_info);
+       btrfs_qgroup_wait_for_completion(fs_info, false);
        spin_lock(&fs_info->qgroup_lock);
        quota_root = fs_info->quota_root;
        fs_info->quota_root = NULL;
@@ -2467,7 +2467,8 @@ btrfs_qgroup_rescan(struct btrfs_fs_info *fs_info)
        return 0;
 }
 
-int btrfs_qgroup_wait_for_completion(struct btrfs_fs_info *fs_info)
+int btrfs_qgroup_wait_for_completion(struct btrfs_fs_info *fs_info,
+                                    bool interruptible)
 {
        int running;
        int ret = 0;
@@ -2478,9 +2479,14 @@ int btrfs_qgroup_wait_for_completion(struct btrfs_fs_info *fs_info)
        spin_unlock(&fs_info->qgroup_lock);
        mutex_unlock(&fs_info->qgroup_rescan_lock);
 
-       if (running)
+       if (!running)
+               return 0;
+
+       if (interruptible)
                ret = wait_for_completion_interruptible(
                                        &fs_info->qgroup_rescan_completion);
+       else
+               wait_for_completion(&fs_info->qgroup_rescan_completion);
 
        return ret;
 }

diff --git a/fs/btrfs/qgroup.h b/fs/btrfs/qgroup.h
index ecb2c143ef756bd0356e3968b3f9f13fe5ac21cd..3d73e4c9c7df3e6afb65c67f3837635202163ee5 100644 (file)
--- a/fs/btrfs/qgroup.h
+++ b/fs/btrfs/qgroup.h
@@ -46,7 +46,8 @@ int btrfs_quota_disable(struct btrfs_trans_handle *trans,
                        struct btrfs_fs_info *fs_info);
 int btrfs_qgroup_rescan(struct btrfs_fs_info *fs_info);
 void btrfs_qgroup_rescan_resume(struct btrfs_fs_info *fs_info);
-int btrfs_qgroup_wait_for_completion(struct btrfs_fs_info *fs_info);
+int btrfs_qgroup_wait_for_completion(struct btrfs_fs_info *fs_info,
+                                    bool interruptible);
 int btrfs_add_qgroup_relation(struct btrfs_trans_handle *trans,
                              struct btrfs_fs_info *fs_info, u64 src, u64 dst);
 int btrfs_del_qgroup_relation(struct btrfs_trans_handle *trans,