@@ -5644,9 +5644,7 @@ long btrfs_ioctl_send(struct file *mnt_file, void __user *arg_)
ret = PTR_ERR(clone_root);
goto out;
}
- clone_sources_to_rollback = i + 1;
spin_lock(&clone_root->root_item_lock);
- clone_root->send_in_progress++;
if (!btrfs_root_readonly(clone_root) ||
btrfs_root_dead(clone_root)) {
spin_unlock(&clone_root->root_item_lock);
@@ -5654,10 +5652,12 @@ long btrfs_ioctl_send(struct file *mnt_file, void __user *arg_)
ret = -EPERM;
goto out;
}
+ clone_root->send_in_progress++;
spin_unlock(&clone_root->root_item_lock);
srcu_read_unlock(&fs_info->subvol_srcu, index);
sctx->clone_roots[i].root = clone_root;
+ clone_sources_to_rollback = i + 1;
}
vfree(clone_sources_tmp);
clone_sources_tmp = NULL;
This is a note to let you know that I have just added a patch titled Btrfs: send, don't leave without decrementing clone root's send_progress to the linux-3.16.y-queue branch of the 3.16.y-ckt extended stable tree which can be found at: http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.16.y-queue This patch is scheduled to be released in version 3.16.7-ckt14. If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 3.16.y-ckt tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Luis ------ From e8f6216d4782f57a9a85c59ef53fb033936cc1a8 Mon Sep 17 00:00:00 2001 From: Filipe Manana <fdmanana@suse.com> Date: Mon, 2 Mar 2015 20:53:53 +0000 Subject: Btrfs: send, don't leave without decrementing clone root's send_progress commit 2f1f465ae6da244099af55c066e5355abd8ff620 upstream. If the clone root was not readonly or the dead flag was set on it, we were leaving without decrementing the root's send_progress counter (and before we just incremented it). If a concurrent snapshot deletion was in progress and ended up being aborted, it would be impossible to later attempt to delete again the snapshot, since the root's send_in_progress counter could never go back to 0. We were also setting clone_sources_to_rollback to i + 1 too early - if we bailed out because the clone root we got is not readonly or flagged as dead we ended up later derreferencing a null pointer because we didn't assign the clone root to sctx->clone_roots[i].root: for (i = 0; sctx && i < clone_sources_to_rollback; i++) btrfs_root_dec_send_in_progress( sctx->clone_roots[i].root); So just don't increment the send_in_progress counter if the root is readonly or flagged as dead. Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.cz> Signed-off-by: Chris Mason <clm@fb.com> Signed-off-by: Luis Henriques <luis.henriques@canonical.com> --- fs/btrfs/send.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)