Btrfs: add support for compat flags to btrfs
This adds the necessary disk format for handling compatibility flags
in the future to handle disk format changes. We have a compat_flags,
compat_ro_flags and incompat_flags set for the super block. Compat
flags will be to hold the features that are compatible with older
versions of btrfs, compat_ro flags have features that are compatible
with older versions of btrfs if the fs is mounted read only, and
incompat_flags has features that are incompatible with older versions
of btrfs. This also axes the compat_flags field for the inode and
just makes the flags field a 64bit field, and changes the root item
flags field to 64bit.
Signed-off-by: Josef Bacik <jbacik@redhat.com>
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 2464c09..6ae9bdf 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -1434,6 +1434,7 @@
u32 blocksize;
u32 stripesize;
u64 generation;
+ u64 features;
struct btrfs_key location;
struct buffer_head *bh;
struct btrfs_root *extent_root = kzalloc(sizeof(struct btrfs_root),
@@ -1586,6 +1587,26 @@
goto fail_sb_buffer;
}
+ features = btrfs_super_incompat_flags(disk_super) &
+ ~BTRFS_FEATURE_INCOMPAT_SUPP;
+ if (features) {
+ printk(KERN_ERR "BTRFS: couldn't mount because of "
+ "unsupported optional features (%Lx).\n",
+ features);
+ err = -EINVAL;
+ goto fail_sb_buffer;
+ }
+
+ features = btrfs_super_compat_ro_flags(disk_super) &
+ ~BTRFS_FEATURE_COMPAT_RO_SUPP;
+ if (!(sb->s_flags & MS_RDONLY) && features) {
+ printk(KERN_ERR "BTRFS: couldn't mount RDWR because of "
+ "unsupported option features (%Lx).\n",
+ features);
+ err = -EINVAL;
+ goto fail_sb_buffer;
+ }
+
/*
* we need to start all the end_io workers up front because the
* queue work function gets called at interrupt time, and so it