From: Jeff Mahoney <jeffm@xxxxxxxx>
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)
Signed-off-by: Jeff Mahoney <jeffm@xxxxxxxx>
---
fs/btrfs/dev-replace.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/fs/btrfs/dev-replace.c b/fs/btrfs/dev-replace.c
index e2ba0419297a..0581c8570a05 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;
--
2.12.3
