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| author | Omar Sandoval <osandov@fb.com> | 2018-05-22 02:07:19 +0200 |
|---|---|---|
| committer | David Sterba <dsterba@suse.com> | 2018-05-28 18:24:13 +0200 |
| commit | 37becec95ac31b209eb1c8e096f1093a7db00f32 (patch) | |
| tree | 87dc9ed68fd8336c81d16e5edc2e3e19bcb39f28 /fs/btrfs/super.c | |
| parent | btrfs: fix describe_relocation when printing unknown flags (diff) | |
| download | linux-37becec95ac31b209eb1c8e096f1093a7db00f32.tar.xz linux-37becec95ac31b209eb1c8e096f1093a7db00f32.zip | |
Btrfs: allow empty subvol= again
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@vger.kernel.org # 4.16+
Signed-off-by: Omar Sandoval <osandov@fb.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'fs/btrfs/super.c')
| -rw-r--r-- | fs/btrfs/super.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c index c67fafaa2fe7..81107ad49f3a 100644 --- a/fs/btrfs/super.c +++ b/fs/btrfs/super.c @@ -323,6 +323,7 @@ enum { Opt_ssd, Opt_nossd, Opt_ssd_spread, Opt_nossd_spread, Opt_subvol, + Opt_subvol_empty, Opt_subvolid, Opt_thread_pool, Opt_treelog, Opt_notreelog, @@ -388,6 +389,7 @@ static const match_table_t tokens = { {Opt_ssd_spread, "ssd_spread"}, {Opt_nossd_spread, "nossd_spread"}, {Opt_subvol, "subvol=%s"}, + {Opt_subvol_empty, "subvol="}, {Opt_subvolid, "subvolid=%s"}, {Opt_thread_pool, "thread_pool=%u"}, {Opt_treelog, "treelog"}, @@ -461,6 +463,7 @@ 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: |