Hi Greg,
On Sun, Nov 11, 2018 at 12:10:46PM -0800, gregkh@xxxxxxxxxxxxxxxxxxx wrote:
>
> The patch below does not apply to the 4.14-stable tree.
> If someone wants it applied there, or to any other stable or longterm
> tree, then please email the backport, including the original git commit
> id to <stable@xxxxxxxxxxxxxxx>.
The attached backported patch should apply to 4.14-stable tree.
--
Regards
Sudip
>From 96e512087f6515984931ec3c7c3e80b9fbc0cfbb Mon Sep 17 00:00:00 2001
From: Jeff Mahoney <jeffm@xxxxxxxx>
Date: Thu, 6 Sep 2018 15:52:17 -0400
Subject: [PATCH] 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@xxxxxxxxxxxxxxx # 4.4+
Signed-off-by: Jeff Mahoney <jeffm@xxxxxxxx>
Reviewed-by: David Sterba <dsterba@xxxxxxxx>
Signed-off-by: David Sterba <dsterba@xxxxxxxx>
Signed-off-by: Sudip Mukherjee <sudipm.mukherjee@xxxxxxxxx>
---
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 dd80a1bdf9e2..68362eddaea2 100644
--- a/fs/btrfs/dev-replace.c
+++ b/fs/btrfs/dev-replace.c
@@ -351,6 +351,7 @@ 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;
}
@@ -395,6 +396,10 @@ int btrfs_dev_replace_start(struct btrfs_fs_info *fs_info,
if (IS_ERR(trans)) {
ret = PTR_ERR(trans);
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;
}
@@ -416,8 +421,6 @@ 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_unlock(dev_replace, 1);
btrfs_destroy_dev_replace_tgtdev(fs_info, tgt_device);
return ret;
--
2.11.0
