MAINTAINERS: add aio to block layer

AioContext falls under the block layer, mark it as such.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
MAINTAINERS: qemu-iotests belongs to the block layer

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
MAINTAINERS: add the image fuzzer to the block layer

More work for the block device maintainers!

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
block/vdi: Use {DIV_,}ROUND_UP

There are macros for these operations, so make use of them.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
block/vdi: Do not use bdrv_pwrite_sync() for bmap

The bmap can be rather large (maximum blocks per image count:
0x3fffffff; the bmap has a size of block_count * sizeof(uint32_t) bytes,
which makes 0xfffffffc bytes) and exceed INT_MAX. Using block layer
functions which take a byte count as an int is therefore not a good
idea. Use bdrv_write()+bdrv_flush() instead of bdrv_pwrite_sync().

See: https://bugzilla.redhat.com/show_bug.cgi?id=1154940

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
block: qemu-iotests change _supported_proto to file once more.

In preparation to possible automatic regression and performance
testing for the block layer I found that the iotests don't work
for all protocols anymore.

In commit 1f7bf7d0 I started to change supported protocols from
generic to file for various tests. Unfortunately, some tests
added in the meantime again carry generic protocol altough they
can only work with file because they require local file access.

The other way around for some tests that only support file I added
NFS protocol after confirming they work.

Signed-off-by: Peter Lieven <pl@kamp.de>
Reviewed-by: Benoît Canet <benoit.canet@nodalink.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
block: Add qemu_{,try_}blockalign0()

These functions call their non-0-counterparts and then fill the
allocated buffer with 0 (if the allocation has been successful).

Signed-off-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
qcow2: Calculate refcount block entry count

The size of a refblock entry is (in theory) variable; calculate
therefore the number of entries per refblock and the according bit shift
(1 << x == entry count) when opening an image.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
qcow2: Fix leaks in dirty images

When opening dirty images, qcow2's repair function should not only
repair errors but leaks as well.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Benoît Canet <benoit.canet@nodalink.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
qcow2: Split qcow2_check_refcounts()

Put the code for calculating the reference counts and comparing them
during qemu-img check into own functions.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Benoît Canet <benoit.canet@nodalink.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
qcow2: Use sizeof(**refcount_table)

When implementing variable refcounts, we want to be able to easily find
all the places in qemu which are tied to a certain refcount order.
Replace sizeof(uint16_t) in the check code by sizeof(**refcount_table)
so we can later find it more easily.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
qcow2: Pull check_refblocks() up

Pull check_refblocks() before calculate_refcounts() so we can drop its
static declaration.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Benoît Canet <benoit.canet@nodalink.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
qcow2: Use int64_t for in-memory reftable size

Use int64_t for the entry count of the in-memory refcount table
throughout the check functions.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
qcow2: Split fail code in L1 and L2 checks

Instead of printing out an error message, incrementing check_errors and
returning a fixed -errno, just do cleanups and return -ret, with ret set
by the code which threw the exception (jumped to the fail label).

Also, increment check_errors on error in check_refcounts_l2().

Signed-off-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
qcow2: Let inc_refcounts() return -errno

As of a future patch, inc_refcounts() will have to throw errors which
are generally signaled by returning -errno. Therefore, let it return an
integer which is either 0 for success or -errno and handle the -errno
case in all callers.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
qcow2: Let inc_refcounts() resize the reftable

Now that the refcount table can be passed around by reference, do that
for inc_refcounts() (and subsequently check_refcounts_l1() and
check_refcounts_l2()) and use it for resizing it when a cluster after
the image end is encountered.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
qcow2: Reuse refcount table in calculate_refcounts()

We will later call calculate_refcounts multiple times, so reuse the
refcount table if possible.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Benoît Canet <benoit.canet@nodalink.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
qcow2: Fix refcount blocks beyond image end

If the qcow2 check function detects a refcount block located beyond the
image end, grow the image appropriately. This cannot break anything and
is the logical fix for such a case.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
qcow2: Do not perform potentially damaging repairs

If a referenced cluster has a refcount of 0, increasing its refcount may
result in clusters being allocated for the refcount structures. This may
overwrite the referenced cluster, therefore we cannot simply increase
the refcount then.

In such cases, we can either try to replicate all the refcount
operations solely for the check operation, basing the allocations on the
in-memory refcount table; or we can simply rebuild the whole refcount
structure based on the in-memory refcount table. Since the latter will
be much easier, do that.

To prepare for this, introduce a "rebuild" boolean which should be set
to true whenever a fix is rather dangerous or too complicated using the
current refcount structures. Another example for this is refcount blocks
being referenced more than once.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
qcow2: Rebuild refcount structure during check

The previous commit introduced the "rebuild" variable to qcow2's
implementation of the image consistency check. Now make use of this by
adding a function which creates a completely new refcount structure
based solely on the in-memory information gathered before.

The old refcount structure will be leaked, however. This leak will be
dealt with in a follow-up commit.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>