Hi Greg,
On Fri, Jun 22, 2018 at 06:16:35AM +0900, gregkh@xxxxxxxxxxxxxxxxxxx wrote:
>
> The patch below does not apply to the 4.16-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 4.16-stable tree.
The list of enum was later sorted by:
416a72022e43 ("btrfs: sort and group mount option definitions") and
so this commit was failing to apply. Backported by putting this new enum
at its proper place.
--
Regards
Sudip
>From cef7464ef76058ffcd1608a995ff46ac3d7db2af Mon Sep 17 00:00:00 2001
From: Omar Sandoval <osandov@xxxxxx>
Date: Mon, 21 May 2018 17:07:19 -0700
Subject: [PATCH] Btrfs: allow empty subvol= again
commit 37becec95ac31b209eb1c8e096f1093a7db00f32 upstream
I got a report that after upgrading to 4.16, someone's filesystems
weren't mounting:
[ 23.845852] BTRFS info (device loop0): unrecognized mount option 'subvol='
Before 4.16, this mounted the default subvolume. It turns out that this
empty "subvol=" is actually an application bug, but it was causing the
application to fail, so it's an ABI break if you squint.
The generic parsing code we use for mount options (match_token())
doesn't match an empty string as "%s". Previously, setup_root_args()
removed the "subvol=" string, but the mount path was cleaned up to not
need that. Add a dummy Opt_subvol_empty to fix this.
The simple workaround is to use / or . for the value of 'subvol=' .
Fixes: 312c89fbca06 ("btrfs: cleanup btrfs_mount() using btrfs_mount_root()")
CC: stable@xxxxxxxxxxxxxxx # 4.16+
Signed-off-by: Omar Sandoval <osandov@xxxxxx>
Reviewed-by: David Sterba <dsterba@xxxxxxxx>
Signed-off-by: David Sterba <dsterba@xxxxxxxx>
Signed-off-by: Sudip Mukherjee <sudipm.mukherjee@xxxxxxxxx>
---
fs/btrfs/super.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 4b817947e00f..8f1e67d0c8c5 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -308,8 +308,9 @@ static void btrfs_put_super(struct super_block *sb)
}
enum {
- Opt_degraded, Opt_subvol, Opt_subvolid, Opt_device, Opt_nodatasum,
- Opt_nodatacow, Opt_max_inline, Opt_alloc_start, Opt_nobarrier, Opt_ssd,
+ Opt_degraded, Opt_subvol, Opt_subvol_empty, Opt_subvolid,
+ Opt_device, Opt_nodatasum, Opt_nodatacow, Opt_max_inline,
+ Opt_alloc_start, Opt_nobarrier, Opt_ssd,
Opt_nossd, Opt_ssd_spread, Opt_thread_pool, Opt_noacl, Opt_compress,
Opt_compress_type, Opt_compress_force, Opt_compress_force_type,
Opt_notreelog, Opt_ratio, Opt_flushoncommit, Opt_discard,
@@ -335,6 +336,7 @@ enum {
static const match_table_t tokens = {
{Opt_degraded, "degraded"},
{Opt_subvol, "subvol=%s"},
+ {Opt_subvol_empty, "subvol="},
{Opt_subvolid, "subvolid=%s"},
{Opt_device, "device=%s"},
{Opt_nodatasum, "nodatasum"},
@@ -440,6 +442,7 @@ int btrfs_parse_options(struct btrfs_fs_info *info, char *options,
btrfs_set_opt(info->mount_opt, DEGRADED);
break;
case Opt_subvol:
+ case Opt_subvol_empty:
case Opt_subvolid:
case Opt_subvolrootid:
case Opt_device:
--
2.11.0
