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Commit c3412080 authored by Jeff Mahoney's avatar Jeff Mahoney Committed by Greg Kroah-Hartman
Browse files

btrfs: fix error handling in btrfs_dev_replace_start 



commit 5c06147128fbbdf7a84232c5f0d808f53153defe upstream.

When we fail to start a transaction in btrfs_dev_replace_start, we leave
dev_replace->replace_start set to STARTED but clear ->srcdev and
->tgtdev.  Later, that can result in an Oops in
btrfs_dev_replace_progress when having state set to STARTED or SUSPENDED
implies that ->srcdev is valid.

Also fix error handling when the state is already STARTED or SUSPENDED
while starting.  That, too, will clear ->srcdev and ->tgtdev even though
it doesn't own them.  This should be an impossible case to hit since we
should be protected by the BTRFS_FS_EXCL_OP bit being set.  Let's add an
ASSERT there while we're at it.

Fixes: e93c89c1 (Btrfs: add new sources for device replace code)
CC: stable@vger.kernel.org # 4.4+
Signed-off-by: default avatarJeff Mahoney <jeffm@suse.com>
Reviewed-by: default avatarDavid Sterba <dsterba@suse.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
Signed-off-by: default avatarSudip Mukherjee <sudipm.mukherjee@gmail.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent dff93bb9

fs/btrfs/dev-replace.c

+5 −2
Original line number Original line Diff line number Diff line
@@ -350,6 +350,7 @@ int btrfs_dev_replace_start(struct btrfs_root *root, char *tgtdev_name, 
		break;

		break;

	case BTRFS_IOCTL_DEV_REPLACE_STATE_STARTED:

	case BTRFS_IOCTL_DEV_REPLACE_STATE_STARTED:

	case BTRFS_IOCTL_DEV_REPLACE_STATE_SUSPENDED:

	case BTRFS_IOCTL_DEV_REPLACE_STATE_SUSPENDED:

		ASSERT(0);

		ret = BTRFS_IOCTL_DEV_REPLACE_RESULT_ALREADY_STARTED;

		ret = BTRFS_IOCTL_DEV_REPLACE_RESULT_ALREADY_STARTED;

		goto leave;

		goto leave;

	}

	}
@@ -394,6 +395,10 @@ int btrfs_dev_replace_start(struct btrfs_root *root, char *tgtdev_name, 
	if (IS_ERR(trans)) {

	if (IS_ERR(trans)) {

		ret = PTR_ERR(trans);

		ret = PTR_ERR(trans);

		btrfs_dev_replace_lock(dev_replace, 1);

		btrfs_dev_replace_lock(dev_replace, 1);

		dev_replace->replace_state =

			BTRFS_IOCTL_DEV_REPLACE_STATE_NEVER_STARTED;

		dev_replace->srcdev = NULL;

		dev_replace->tgtdev = NULL;

		goto leave;

		goto leave;

	}

	}
@@ -415,8 +420,6 @@ int btrfs_dev_replace_start(struct btrfs_root *root, char *tgtdev_name, 
	return ret;

	return ret;





leave:

leave:

	dev_replace->srcdev = NULL;

	dev_replace->tgtdev = NULL;

	btrfs_dev_replace_unlock(dev_replace, 1);

	btrfs_dev_replace_unlock(dev_replace, 1);

	btrfs_destroy_dev_replace_tgtdev(fs_info, tgt_device);

	btrfs_destroy_dev_replace_tgtdev(fs_info, tgt_device);

	return ret;

	return ret;