From: Jeff Mahoney Date: Thu, 6 Sep 2018 19:52:17 +0000 (-0400) Subject: btrfs: fix error handling in btrfs_dev_replace_start X-Git-Tag: v4.18.19~31 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=449f9b8dcf15d02d64ccb111ed5191ae0d6f198d;p=thirdparty%2Fkernel%2Fstable.git 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: e93c89c1aaaaa (Btrfs: add new sources for device replace code) CC: stable@vger.kernel.org # 4.4+ Signed-off-by: Jeff Mahoney Reviewed-by: David Sterba Signed-off-by: David Sterba Signed-off-by: Greg Kroah-Hartman --- diff --git a/fs/btrfs/dev-replace.c b/fs/btrfs/dev-replace.c index d20b244623f2d..e129a595f811e 100644 --- a/fs/btrfs/dev-replace.c +++ b/fs/btrfs/dev-replace.c @@ -445,6 +445,7 @@ int btrfs_dev_replace_start(struct btrfs_fs_info *fs_info, break; case BTRFS_IOCTL_DEV_REPLACE_STATE_STARTED: case BTRFS_IOCTL_DEV_REPLACE_STATE_SUSPENDED: + ASSERT(0); ret = BTRFS_IOCTL_DEV_REPLACE_RESULT_ALREADY_STARTED; goto leave; } @@ -487,6 +488,10 @@ int btrfs_dev_replace_start(struct btrfs_fs_info *fs_info, if (IS_ERR(trans)) { ret = PTR_ERR(trans); btrfs_dev_replace_write_lock(dev_replace); + dev_replace->replace_state = + BTRFS_IOCTL_DEV_REPLACE_STATE_NEVER_STARTED; + dev_replace->srcdev = NULL; + dev_replace->tgtdev = NULL; goto leave; } @@ -508,8 +513,6 @@ int btrfs_dev_replace_start(struct btrfs_fs_info *fs_info, return ret; leave: - dev_replace->srcdev = NULL; - dev_replace->tgtdev = NULL; btrfs_dev_replace_write_unlock(dev_replace); btrfs_destroy_dev_replace_tgtdev(fs_info, tgt_device); return ret;