The inode btrees track 64 inodes per record regardless of inode size.
Thus, inode chunks on disk vary in size depending on the size of the
inodes. This creates a contiguous allocation requirement for new inode
chunks that can be difficult to satisfy on an aged and fragmented (free
space) filesystems.
The inode record freecount currently uses 4 bytes on disk to track the
free inode count. With a maximum freecount value of 64, only one byte is
required. Convert the freecount field to a single byte and use two of
the remaining 3 higher order bytes left for the hole mask field. Use the
final leftover byte for the total count field.
The hole mask field tracks holes in the chunks of physical space that
the inode record refers to. This facilitates the sparse allocation of
inode chunks when contiguous chunks are not available and allows the
inode btrees to identify what portions of the chunk contain valid
inodes. The total count field contains the total number of valid inodes
referred to by the record. This can also be deduced from the hole mask.
The count field provides clarity and redundancy for internal record
verification.
Note that neither of the new fields can be written to disk on fs'
without sparse inode support. Doing so writes to the high-order bytes of
freecount and causes corruption from the perspective of older kernels.
The on-disk inobt record data structure is updated with a union to
distinguish between the original, "full" format and the new, "sparse"
format. The conversion routines to get, insert and update records are
updated to translate to and from the on-disk record accordingly such
that freecount remains a 4-byte value on non-supported fs, yet the new
fields of the in-core record are always valid with respect to the
record. This means that higher level code can refer to the current
in-core record format unconditionally and lower level code ensures that
records are translated to/from disk according to the capabilities of the
fs.
Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
The sparse inode chunks feature uses the helper function to enable the
allocation of sparse inode chunks. The incompatible feature bit is set
on disk at mkfs time to prevent mount from unsupported kernels.
Also, enforce the inode alignment requirements required for sparse inode
chunks at mount time. When enabled, full inode chunks (and all inode
record) alignment is increased from cluster size to inode chunk size.
Sparse inode alignment must match the cluster size of the fs. Both
superblock alignment fields are set as such by mkfs when sparse inode
support is enabled.
Finally, warn that sparse inode chunks is an experimental feature until
further notice.
Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Add sb_spino_align to the superblock to specify sparse inode chunk
alignment. This also currently represents the minimum allowable sparse
chunk allocation size.
Signed-off-by: Brian Foster <bfoster@redhat.com>
Now that there are no users of the bitfield based incore superblock
modification API, just remove the whole damn lot of it, including
all the bitfield definitions. This finally removes a lot of cruft
that has been around for a long time.
Credit goes to Christoph Hellwig for providing a great patch
connecting all the dots to enale us to do this. This patch is
derived from that work.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
We currently have to ensure that every time we update sb_features2
that we update sb_bad_features2. Now that we log and format the
superblock in it's entirety we actually don't have to care because
we can simply update the sb_bad_features2 when we format it into the
buffer. This removes the need for anything but the mount and
superblock formatting code to care about sb_bad_features2, and
hence removes the possibility that we forget to update bad_features2
when necessary in the future.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Currently when we modify sb_features2, we store the same value also in
sb_bad_features2. However in most places we forget to mark field
sb_bad_features2 for logging and thus it can happen that a change to it
is lost. This results in an inconsistent sb_features2 and
sb_bad_features2 fields e.g. after xfstests test xfs/187.
Fix the problem by changing XFS_SB_FEATURES2 to actually mean both
sb_features2 and sb_bad_features2 fields since this is always what we
want to log. This isn't ideal because the fact that XFS_SB_FEATURES2
means two fields could cause some problem in future however the code is
hopefully less error prone that it is now.
Signed-off-by: Jan Kara <jack@suse.cz>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
More on-disk format consolidation.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
More on-disk format consolidation. A few declarations that weren't on-disk
format related move into better suitable spots.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Move the on-disk ACL format to xfs_format.h, so that repair can
use the common defintion.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
More consolidatation for the on-disk format defintions. Note that the
XFS_IS_REALTIME_INODE moves to xfs_linux.h instead as it is not related
to the on disk format, but depends on a CONFIG_ option.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Trying to support tiny disks only and saving a bit memory might have
made sense on an SGI O2 15 years ago, but is pretty pointless today.
Remove the rarely tested codepath that uses various smaller in-memory
types to reduce our test matrix and make the codebase a little bit
smaller and less complicated.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Ben Myers <bpm@sgi.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Move all the header files that are shared with userspace into
libxfs. This is done as one big chunk simpy to get it done quickly.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
