There were a number of handwaving complaints that one could "possibly"
use inode numbers and extent maps to fingerprint a filesystem hosting
multiple containers and somehow use the information to guess at the
contents of other containers and attack them. Despite the total lack of
any demonstration that this is actually possible, it's easier to
restrict access now and broaden it later, so use the rmapbt fsmap
backends only if the caller has CAP_SYS_ADMIN. Unprivileged users will
just have to make do with only getting the free space and static
metadata placement information.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>
Found by sparse.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Use the realtime bitmap to return free space information via getfsmap.
Eventually this will be superseded by the realtime rmapbt code.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
If the reverse-mapping btree isn't available, fall back to the
free space btrees to provide partial reverse mapping information.
The online scrub tool can make use of even partial information to
speed up the data block scan.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Introduce a new ioctl that uses the reverse mapping btree to return
information about the physical layout of the filesystem.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Darrick J. Wong