[PATCH] Btrfs: fix sync subvol/snapshot creation

[PATCH] Btrfs: fix sync subvol/snapshot creation

[Sage Weil]

We were incorrectly taking the async path even for the sync ioctls by
passing in &transid unconditionally.

There's ample room for further cleanup here, but this keeps the fix simple.

Signed-off-by: Sage Weil <sage@newdream.net>
---
 fs/btrfs/ioctl.c |   20 +++++++++++---------
 1 files changed, 11 insertions(+), 9 deletions(-)

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 41614c3..4c2d7c4 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -970,6 +970,15 @@ static noinline int btrfs_ioctl_snap_create(struct file *file,
 		name = async_vol_args->name;
 		fd = async_vol_args->fd;
 		async_vol_args->name[BTRFS_SNAPSHOT_NAME_MAX] = '\0';
+
+		ret = btrfs_ioctl_snap_create_transid(file, name, fd,
+						      subvol, &transid);
+
+		if (ret == 0 &&
+		    copy_to_user(arg +
+				 offsetof(struct btrfs_ioctl_async_vol_args,
+					  transid), &transid, sizeof(transid)))
+			ret = -EFAULT;
 	} else {
 		vol_args = memdup_user(arg, sizeof(*vol_args));
 		if (IS_ERR(vol_args))
@@ -977,16 +986,9 @@ static noinline int btrfs_ioctl_snap_create(struct file *file,
 		name = vol_args->name;
 		fd = vol_args->fd;
 		vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
-	}
-
-	ret = btrfs_ioctl_snap_create_transid(file, name, fd,
-					      subvol, &transid);
 
-	if (!ret && async) {
-		if (copy_to_user(arg +
-				offsetof(struct btrfs_ioctl_async_vol_args,
-				transid), &transid, sizeof(transid)))
-			return -EFAULT;
+		ret = btrfs_ioctl_snap_create_transid(file, name, fd,
+						      subvol, NULL);
 	}
 
 	kfree(vol_args);
-- 
1.6.6.1

Re: [PATCH] Btrfs: fix sync subvol/snapshot creation

[Li Zefan]

Sage Weil wrote:
> We were incorrectly taking the async path even for the sync ioctls by
> passing in &transid unconditionally.
> 

Ha, I fixed this accidentally in my patchset. :)

> There's ample room for further cleanup here, but this keeps the fix simple.
> 
> Signed-off-by: Sage Weil <sage@newdream.net>

Reviewed-by: Li Zefan <lizf@cn.fujitsu.com>

Re: [PATCH] Btrfs: fix sync subvol/snapshot creation

[Chris Mason]

Excerpts from Li Zefan's message of 2010-12-09 21:11:25 -0500:
> Sage Weil wrote:
> > We were incorrectly taking the async path even for the sync ioctls by
> > passing in &transid unconditionally.
> > 
> 
> Ha, I fixed this accidentally in my patchset. :)

Thanks guys,

Unless either of you object, I'll take this and the snapshot ABI change
for the next rc.

-chris

Re: [PATCH] Btrfs: fix sync subvol/snapshot creation

[Sage Weil]

On Thu, 9 Dec 2010, Chris Mason wrote:
> Excerpts from Li Zefan's message of 2010-12-09 21:11:25 -0500:
> > Sage Weil wrote:
> > > We were incorrectly taking the async path even for the sync ioctls by
> > > passing in &transid unconditionally.
> > > 
> > 
> > Ha, I fixed this accidentally in my patchset. :)
>
> Thanks guys,
> 
> Unless either of you object, I'll take this and the snapshot ABI change
> for the next rc.

Sounds good to me.

Just FYI, I'm still seeing some weird corruption and crashes on my 
machines and haven't narrowed it down yet.  Should have more info soon.

sage