Commit Graph

62 Commits

Author SHA1 Message Date
Markus Armbruster 6528499fa4 g_malloc(0) and g_malloc0(0) return NULL; simplify
Once upon a time, it was decided that qemu_malloc(0) should abort.
Switching to glib retired that bright idea.  Some code that was added
to cope with it (e.g. in commits 702ef63, b76b6e9) is still around.
Bury it.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-01-30 11:14:46 +01:00
Paolo Bonzini 737e150e89 block: move include files to include/block/
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2012-12-19 08:31:31 +01:00
Kevin Wolf a354807706 qcow2: Fix refcount table size calculation
A missing factor for the refcount table entry size in the calculation
could mean that too little memory was allocated for the in-memory
representation of the table, resulting in a buffer overflow.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Michael Tokarev <mjt@tls.msk.ru>
Tested-by: Michael Tokarev <mjt@tls.msk.ru>
2012-11-14 18:19:21 +01:00
Stefan Hajnoczi 206e6d8551 qcow2: preserve free_byte_offset when qcow2_alloc_bytes() fails
When qcow2_alloc_clusters() error handling code was introduced in commit
5d757b563d, the value of free_byte_offset
was clobbered in the error case.  This patch keeps free_byte_offset at 0
so we will try to allocate clusters again next time this function is
called.

Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2012-07-09 15:53:01 +02:00
Paolo Bonzini 6af4e9ead4 qcow2: always operate caches in writeback mode
Writethrough does not need special-casing anymore in the qcow2 caches.
The block layer adds flushes after every guest-initiated data write,
and these will also flush the qcow2 caches to the OS.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2012-06-15 14:03:43 +02:00
Kevin Wolf 166acf546f qcow2: Support for fixing refcount inconsistencies
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2012-06-15 14:03:42 +02:00
Zhi Yong Wu 87267753a3 qcow2: fix endianness conversion
Signed-off-by: Zhi Yong Wu <wuzhy@linux.vnet.ibm.com>
Reviewed-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2012-06-15 14:03:42 +02:00
Kevin Wolf 6377af48b0 qcow2: Support reading zero clusters
This adds support for reading zero clusters in version 3 images.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2012-04-20 15:57:29 +02:00
Kevin Wolf afdf0abe77 qcow2: Ignore reserved bits in check_refcounts
Also don't infer the cluster type directly from the L2 entries, but use
qcow2_get_cluster_type() to keep everything in a single place.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2012-04-20 15:57:29 +02:00
Kevin Wolf 76dc9e0c8f qcow2: Ignore reserved bits in refcount table entries
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2012-04-20 15:57:29 +02:00
Kevin Wolf c7a4c37a0f qcow2: Refactor qcow2_free_any_clusters
Zero clusters will add another cluster type. Refactor the open-coded
cluster type detection into a switch of QCOW2_CLUSTER_* options so that
the detection is in a single place. This makes it easier to add new
cluster types.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2012-04-20 15:57:28 +02:00
Kevin Wolf 8e37f681d5 qcow2: Ignore reserved bits in L1/L2 entries
This changes the still existing places that assume that the only flags
are QCOW_OFLAG_COPIED and QCOW_OFLAG_COMPRESSED to properly mask out
reserved bits.

It does not convert bdrv_check yet.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2012-04-20 15:57:28 +02:00
Kevin Wolf f24423bd90 qcow2: Fix refcount block allocation during qcow2_alloc_cluster_at()
Refcount block allocation and refcount table growth rely on
s->free_cluster_index pointing to somewhere after the current
allocation. Change qcow2_alloc_cluster_at() to fulfill this
assumption.

Without this change it could happen that a newly allocated refcount
block and the allocated data block point to the same area in the image
file, causing data corruption in the long run.

This fixes a bug that became first visible after commit 250196f1.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2012-04-20 15:56:19 +02:00
Kevin Wolf 2795ecf681 qcow2: Fix return value of alloc_refcount_block
Someone forgot something in commit 29c1a730... Documenting the right
return value is not enough, you also need to actually return it in the
code.

This bug sometimes causes error return values even when everything has
succeeded: The new offset of the refcount block is truncated to 32 bits
and interpreted as signed. At least with small cluster sizes it's easy
to get a negative return value this way.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
2012-04-19 16:03:27 +02:00
Kevin Wolf 256900b16b qcow2: Add qcow2_alloc_clusters_at()
This function allows to allocate clusters at a given offset in the image
file. This is useful if you want to allocate the second part of an area
that must be contiguous.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
2012-03-12 15:14:07 +01:00
Kevin Wolf 43a0cac465 qcow2: Fix order of refcount updates in qcow2_snapshot_goto
The refcount updates must be moved so that in the worst case we can get
cluster leaks, but refcounts may never be too low.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
2011-12-05 14:51:36 +01:00
Frediano Ziglio 2f4b759367 qcow2: remove unused qcow2_create_refcount_update function
Signed-off-by: Frediano Ziglio <freddy77@gmail.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-08-25 15:23:10 +02:00
Frediano Ziglio 35ee5e39c5 qcow2: use always stderr for debugging
let all DEBUG_ALLOC2 printf goes to stderr

Signed-off-by: Frediano Ziglio <freddy77@gmail.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-08-25 15:22:25 +02:00
Anthony Liguori 7267c0947d Use glib memory allocation and free functions
qemu_malloc/qemu_free no longer exist after this commit.

Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2011-08-20 23:01:08 -05:00
Kevin Wolf 93913dfd8a qcow2: Use Qcow2Cache in writeback mode during loadvm/savevm
In snapshotting there is no guest involved, so we can safely use a writeback
mode and do the flushes in the right place (i.e. at the very end). This
improves the time that creating/restoring an internal snapshot takes with an
image in writethrough mode.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-07-19 15:39:22 +02:00
Kevin Wolf 80fa3341a7 qcow2: Fix memory leaks in error cases
This fixes memory leaks that may be caused by I/O errors during L1 table growth
(can happen during save_vm) and in qemu-img check.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-06-08 11:56:40 +02:00
Stefan Weil a1c7273b82 Fix typos in comments and code (occured -> occurred and related)
The code changed here is an unused data type name (evt_flush_occurred).

Signed-off-by: Stefan Weil <weil@mail.berlios.de>
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
2011-05-08 10:02:18 +01:00
Blue Swirl 1869a65385 qcow2-refcount: remove write-only variables
Variables l2_modified and l2_size are not really used, remove them.
Spotted by GCC 4.6.0:
  CC    block/qcow2-refcount.o
/src/qemu/block/qcow2-refcount.c: In function 'qcow2_update_snapshot_refcount':
/src/qemu/block/qcow2-refcount.c:708:37: error: variable 'l2_modified' set but not used [-Werror=unused-but-set-variable]
/src/qemu/block/qcow2-refcount.c:708:9: error: variable 'l2_size' set but not used [-Werror=unused-but-set-variable]

CC: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-01-31 10:05:34 +01:00
Kevin Wolf 29c1a7301a qcow2: Use QcowCache
Use the new functions of qcow2-cache.c for everything that works on refcount
block and L2 tables.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-01-24 16:41:49 +01:00
Kevin Wolf 1c02e2a171 qcow2: Invalidate cache after failed read
The cache content may be destroyed after a failed read, better not use it any
more.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
2010-11-04 13:54:37 +01:00
Blue Swirl 83e3f76c25 block: avoid a write only variable
Compiling with GCC 4.6.0 20100925 produced a warning:
/src/qemu/block/qcow2-refcount.c: In function 'update_refcount':
/src/qemu/block/qcow2-refcount.c:552:13: error: variable 'dummy' set but not used [-Werror=unused-but-set-variable]

Fix by adding a dummy cast so that the result is not unused.

Acked-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
2010-10-13 18:38:07 +00:00
Kevin Wolf 29216ed14f qcow2: Move sync out of qcow2_alloc_clusters
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2010-09-21 15:39:42 +02:00
Kevin Wolf 1c4c28149f qcow2: Move sync out of update_refcount
Note that the flush is omitted intentionally in qcow2_free_clusters. If
anything, we can leak clusters here if we lose the writes.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2010-09-21 15:39:42 +02:00
Kevin Wolf c01828fb51 qcow2: Move sync out of write_refcount_block_entries
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2010-09-21 15:39:42 +02:00
Kevin Wolf 9ac228e02c qcow2/vdi: Change check to distinguish error cases
This distinguishes between harmless leaks and real corruption. Hopefully users
better understand what qemu-img check wants to tell them.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2010-07-06 17:05:49 +02:00
Kevin Wolf f74550fd53 qcow2: Don't try to check tables that couldn't be loaded
Trying to check them leads to a second error message which is more confusing
than helpful:

    Can't get refcount for cluster 0: Invalid argument
    ERROR cluster 0 refcount=-22 reference=1

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2010-06-22 14:38:02 +02:00
Kevin Wolf 6882c8fa78 qcow2: Fix qemu-img check segfault on corrupted images
With corrupted images, we can easily get an cluster index that exceeds the
array size of the temporary refcount table.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2010-06-22 14:38:02 +02:00
Kevin Wolf 8b3b720620 qcow2: Use bdrv_(p)write_sync for metadata writes
Use bdrv_(p)write_sync to ensure metadata integrity in case of a crash.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2010-06-22 14:38:02 +02:00
Kevin Wolf e14e8ba5d0 qcow2: Return real error code in load_refcount_block
This fixes load_refcount_block which completely ignored the return value of
write_refcount_block and always returned -EIO for bdrv_pwrite failure.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2010-06-15 09:41:58 +02:00
Kevin Wolf 2eaa8f6338 qcow2: Allow alloc_clusters_noref to return errors
Currently it would consider blocks for which get_refcount fails used. However,
it's unlikely that get_refcount would succeed for the next cluster, so it's not
really helpful. Return an error instead.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2010-06-15 09:41:58 +02:00
Kevin Wolf 018faafdbd qcow2: Allow get_refcount to return errors
get_refcount might need to load a refcount block from disk, so errors may
happen. Return the error code instead of assuming a refcount of 1 and change
the callers to respect error return values.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2010-06-15 09:41:58 +02:00
Kevin Wolf 86fa8da837 qcow2: Fix corruption after error in update_refcount
After it is done with updating refcounts in the cache, update_refcount writes
all changed entries to disk. If a refcount block allocation fails, however,
there was no change yet and therefore first_index = last_index = -1. Don't
treat -1 as a normal sector index (resulting in a 512 byte write!) but return
without updating anything in this case.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2010-05-28 13:29:16 +02:00
Kevin Wolf 25408c0950 qcow2: Fix corruption after refblock allocation
Refblock allocation code needs to take into consideration that update_refcount
will load a different refcount block into the cache, so it must initialize the
cache for a new refcount block only afterwards. Not doing this means that not
only the refcount in the wrong block is updated, but also that the caller will
work on the wrong block.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2010-05-28 13:29:15 +02:00
Kevin Wolf ed0df867d9 qcow2: Return right error code in write_refcount_block_entries
write_refcount_block_entries used to return -EIO for any errors. Change this to
return the real error code.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2010-05-28 13:29:13 +02:00
Kevin Wolf 003fad6e2c qcow2: Remove abort on free_clusters failure
While it's true that during regular operation free_clusters failure would be a
bug, an I/O error can always happen. There's no need to kill the VM, the worst
thing that can happen (and it will) is that we leak some clusters.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2010-05-03 10:07:32 +02:00
Stefan Hajnoczi 508e089368 qcow2: Avoid shadowing variable in alloc_clusters_noref()
The i loop iterator is shadowed by the next free cluster index.  Both
using the variable name 'i' makes the code harder to read.

Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2010-05-03 10:07:31 +02:00
Kevin Wolf 66f82ceed6 block: Open the underlying image file in generic code
Format drivers shouldn't need to bother with things like file names, but rather
just get an open BlockDriverState for the underlying protocol. This patch
introduces this behaviour for bdrv_open implementation. For protocols which
need to access the filename to open their file/device/connection/... a new
callback bdrv_file_open is introduced which doesn't get an underlying file
opened.

For now, also some of the more obscure formats use bdrv_file_open because they
open() the file themselves instead of using the block.c functions. They need to
be fixed in later patches.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2010-05-03 10:07:30 +02:00
Kevin Wolf 8252278afb qcow2: Trigger blkdebug events
This adds blkdebug events to qcow2 to allow injecting I/O errors in specific
places.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2010-04-23 16:08:46 +02:00
Kevin Wolf 746c3cb5d5 qcow2: More checks for qemu-img check
Implement some more refcount block related checks

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2010-02-23 13:23:29 -06:00
Kevin Wolf 92dcb59fd4 qcow2: Rewrite alloc_refcount_block/grow_refcount_table
The current implementation of alloc_refcount_block and grow_refcount_table has
fundamental problems regarding error handling. There are some places where an
I/O error means that the image is going to be corrupted. I have found that the
only way to fix this is to completely rewrite the thing.

In detail, the problem is that the refcount blocks itself are allocated using
alloc_refcount_noref (to avoid endless recursion when updating the refcount of
the new refcount block, which migh access just the same refcount block but its
allocation is not yet completed...). Only at the end of the refcount allocation
the refcount of the refcount block is increased. If an error happens in
between, the refcount block is in use, but has a refcount of zero and will
likely be overwritten later.

The new approach is explained in comments in the code. The trick is basically
to let new refcount blocks describe their own refcount, so their refcount will
be automatically changed when they are hooked up in the refcount table.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2010-02-23 13:23:29 -06:00
Kevin Wolf 05121aedc4 qcow2: Factor next_refcount_table_size out
When the refcount table grows, it doesn't only grow by one entry but reserves
some space for future refcount blocks. The algorithm to calculate the number of
entries stays the same with the fixes, so factor it out before replacing the
rest.

As Juan suggested take the opportunity to simplify the code a bit.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2010-02-23 13:23:29 -06:00
Kevin Wolf 5d757b563d qcow2: Don't ignore qcow2_alloc_clusters return value
Now that qcow2_alloc_clusters can return error codes, we must handle them in
the callers of qcow2_alloc_clusters.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2010-01-26 14:59:19 -06:00
Kevin Wolf db3a964fb6 qcow2: Don't ignore update_refcount return value
update_refcount can return errors that need to be handled by the callers.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2010-01-26 14:59:19 -06:00
Kevin Wolf 7322afe7ea qcow2: Allow updating no refcounts
There's absolutely no problem with updating the refcounts of 0 clusters.
At least snapshot code is doing this and would fail once the result of
update_refcount isn't ignored any more.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2010-01-26 14:59:19 -06:00
Kevin Wolf 09508d13f3 qcow2: Improve error handling in update_refcount
If update_refcount fails, try to undo any changes made so far to avoid
inconsistencies in the image file.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2010-01-26 14:59:19 -06:00