The qed_bytes_to_clusters() function is normally used with size_t
lengths.  Consistency check used it with file size length and therefore
failed on 32-bit hosts when the image file is 4 GB or more.

Make qed_bytes_to_clusters() explicitly 64-bit and update consistency
check to keep 64-bit cluster counts.
Reported-by: NMichael Tokarev <mjt@tls.msk.ru>
Signed-off-by: NStefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

Zero clusters are similar to unallocated clusters except instead of reading
their value from a backing file when one is available, the cluster is always
read as zero.

This implements read support only.  At this stage, QED will never write a
zero cluster.
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>
Signed-off-by: NStefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

This patch adds support for the qemu-img check command.  It also
introduces a dirty bit in the qed header to mark modified images as
needing a check.  This bit is cleared when the image file is closed
cleanly.

If an image file is opened and it has the dirty bit set, a consistency
check will run and try to fix corrupted table offsets.  These
corruptions may occur if there is power loss while an allocating write
is performed.  Once the image is fixed it opens as normal again.
Signed-off-by: NStefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

This patch implements the read/write state machine.  Operations are
fully asynchronous and multiple operations may be active at any time.

Allocating writes lock tables to ensure metadata updates do not
interfere with each other.  If two allocating writes need to update the
same L2 table they will run sequentially.  If two allocating writes need
to update different L2 tables they will run in parallel.
Signed-off-by: NStefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

This patch adds code to look up data cluster offsets in the image via
the L1/L2 tables.  The L2 tables are writethrough cached in memory for
performance (each read/write requires a lookup so it is essential to
cache the tables).

With cluster lookup code in place it is possible to implement
bdrv_is_allocated() to query the number of contiguous
allocated/unallocated clusters.
Signed-off-by: NStefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

This patch introduces the qed on-disk layout and implements image
creation.  Later patches add read/write and other functionality.
Signed-off-by: NStefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>