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Diffstat (limited to 'fs/btrfs/reada.c')
-rw-r--r--fs/btrfs/reada.c47
1 files changed, 47 insertions, 0 deletions
diff --git a/fs/btrfs/reada.c b/fs/btrfs/reada.c
index 9d4f5316a7e8..d9a166eb344e 100644
--- a/fs/btrfs/reada.c
+++ b/fs/btrfs/reada.c
@@ -421,6 +421,9 @@ static struct reada_extent *reada_find_extent(struct btrfs_fs_info *fs_info,
if (!dev->bdev)
continue;
+ if (test_bit(BTRFS_DEV_STATE_NO_READA, &dev->dev_state))
+ continue;
+
if (dev_replace_is_ongoing &&
dev == fs_info->dev_replace.tgtdev) {
/*
@@ -445,6 +448,8 @@ static struct reada_extent *reada_find_extent(struct btrfs_fs_info *fs_info,
}
have_zone = 1;
}
+ if (!have_zone)
+ radix_tree_delete(&fs_info->reada_tree, index);
spin_unlock(&fs_info->reada_lock);
up_read(&fs_info->dev_replace.rwsem);
@@ -1020,3 +1025,45 @@ void btrfs_reada_detach(void *handle)
kref_put(&rc->refcnt, reada_control_release);
}
+
+/*
+ * Before removing a device (device replace or device remove ioctls), call this
+ * function to wait for all existing readahead requests on the device and to
+ * make sure no one queues more readahead requests for the device.
+ *
+ * Must be called without holding neither the device list mutex nor the device
+ * replace semaphore, otherwise it will deadlock.
+ */
+void btrfs_reada_remove_dev(struct btrfs_device *dev)
+{
+ struct btrfs_fs_info *fs_info = dev->fs_info;
+
+ /* Serialize with readahead extent creation at reada_find_extent(). */
+ spin_lock(&fs_info->reada_lock);
+ set_bit(BTRFS_DEV_STATE_NO_READA, &dev->dev_state);
+ spin_unlock(&fs_info->reada_lock);
+
+ /*
+ * There might be readahead requests added to the radix trees which
+ * were not yet added to the readahead work queue. We need to start
+ * them and wait for their completion, otherwise we can end up with
+ * use-after-free problems when dropping the last reference on the
+ * readahead extents and their zones, as they need to access the
+ * device structure.
+ */
+ reada_start_machine(fs_info);
+ btrfs_flush_workqueue(fs_info->readahead_workers);
+}
+
+/*
+ * If when removing a device (device replace or device remove ioctls) an error
+ * happens after calling btrfs_reada_remove_dev(), call this to undo what that
+ * function did. This is safe to call even if btrfs_reada_remove_dev() was not
+ * called before.
+ */
+void btrfs_reada_undo_remove_dev(struct btrfs_device *dev)
+{
+ spin_lock(&dev->fs_info->reada_lock);
+ clear_bit(BTRFS_DEV_STATE_NO_READA, &dev->dev_state);
+ spin_unlock(&dev->fs_info->reada_lock);
+}