Commit 79ba8c98 (v2.7) changed the setting of request_alignment
to occur only during bdrv_refresh_limits(), rather than at at
bdrv_open() time; but at the time, NBD was unaffected, because
it still used sector-based callbacks, so the block layer
defaulted NBD to use 512 request_alignment.
Later, commit 70c4fb26 (also v2.7) changed NBD to use byte-based
callbacks, without setting request_alignment. This resulted in
NBD using request_alignment of 1, which works great when the
server supports it (as is the case for qemu-nbd), but falls apart
miserably if the server requires alignment (but only if qemu
actually sends a sub-sector request; qemu-io can do it, but
most qemu operations still perform on sectors or larger).
Even later, the NBD protocol was updated to document that clients
should learn the server's minimum alignment during NBD_OPT_GO;
and recommended that clients should assume a minimum size of 512
unless the server understands NBD_OPT_GO and replied with a smaller
size. Commit 081dd1fe (v2.10) attempted to do that, by assigning
request_alignment to whatever was learned from the server; but
it has two flaws: the assignment is done during bdrv_open() so
it gets unconditionally wiped out back to 1 during any later
bdrv_refresh_limits(); and the code is not using a default of 512
when the server did not report a minimum size.
Fix these issues by moving the assignment to request_alignment
to the right function, and by using a sane default when the
server does not advertise a minimum size.
CC: qemu-stable@nongnu.org
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20180215032905.27146-1-eblake@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy<vsementsov@virtuozzo.com>
1) string not null terminated in sysfs_find_group_file
2) NULL pointer dereference and dead local variable in nvme_init.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Fam Zheng <famz@redhat.com>
Message-Id: <20180213015240.9352-1-famz@redhat.com>
Signed-off-by: Fam Zheng <famz@redhat.com>
Now that the code is ready to handle L2 slices we can finally add an
option to allow configuring their size.
An L2 slice is the portion of an L2 table that is read by the qcow2
cache. Until now the cache was always reading full L2 tables, and
since the L2 table size is equal to the cluster size this was not very
efficient with large clusters. Here's a more detailed explanation of
why it makes sense to have smaller cache entries in order to load L2
data:
https://lists.gnu.org/archive/html/qemu-block/2017-09/msg00635.html
This patch introduces a new command-line option to the qcow2 driver
named l2-cache-entry-size (cf. l2-cache-size). The cache entry size
has the same restrictions as the cluster size: it must be a power of
two and it has the same range of allowed values, with the additional
requirement that it must not be larger than the cluster size.
The L2 cache entry size (L2 slice size) remains equal to the cluster
size for now by default, so this feature must be explicitly enabled.
Although my tests show that 4KB slices consistently improve
performance and give the best results, let's wait and make more tests
with different cluster sizes before deciding on an optimal default.
Now that the cache entry size is not necessarily equal to the cluster
size we need to reflect that in the MIN_L2_CACHE_SIZE documentation.
That minimum value is a requirement of the COW algorithm: we need to
read two L2 slices (and not two L2 tables) in order to do COW, see
l2_allocate() for the actual code.
Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: c73e5611ff4a9ec5d20de68a6c289553a13d2354.1517840877.git.berto@igalia.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
This function doesn't need any changes to support L2 slices, but since
it's now dealing with slices intead of full tables, the l2_table
variable is renamed for clarity.
Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: 6107001fc79e6739242f1de7d191375e4f130aac.1517840877.git.berto@igalia.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
This function doesn't need any changes to support L2 slices, but since
it's now dealing with slices instead of full tables, the l2_table
variable is renamed for clarity.
Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: 78bcc54bc632574dd0b900a77a00a1b6ffc359e6.1517840877.git.berto@igalia.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
This function doesn't need any changes to support L2 slices, but since
it's now dealing with slices intead of full tables, the l2_table
variable is renamed for clarity.
Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: 812b0c3505bb1687e51285dccf1a94f0cecb1f74.1517840877.git.berto@igalia.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
This function doesn't need any changes to support L2 slices, but since
it's now dealing with slices instead of full tables, the l2_table
variable is renamed for clarity.
Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: 0c5d4b9bf163aa3b49ec19cc512a50d83563f2ad.1517840877.git.berto@igalia.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
The qcow2_truncate() code is mostly independent from whether
we're using L2 slices or full L2 tables, but in full and
falloc preallocation modes new L2 tables are allocated using
qcow2_alloc_cluster_link_l2(). Therefore the code needs to be
modified to ensure that all nb_clusters that are processed in each
call can be allocated with just one L2 slice.
Signed-off-by: Alberto Garcia <berto@igalia.com>
Message-id: 1fd7d272b5e7b66254a090b74cf2bed1cc334c0e.1517840877.git.berto@igalia.com
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
expand_zero_clusters_in_l1() expands zero clusters as a necessary step
to downgrade qcow2 images to a version that doesn't support metadata
zero clusters. This function takes an L1 table (which may or may not
be active) and iterates over all its L2 tables looking for zero
clusters.
Since we'll be loading L2 slices instead of full tables we need to add
an extra loop that iterates over all slices of each L2 table, and we
should also use the slice size when allocating the buffer used when
the L1 table is not active.
This function doesn't need any additional changes so apart from that
this patch simply updates the variable name from l2_table to l2_slice.
Finally, and since we have to touch the bdrv_read() / bdrv_write()
calls anyway, this patch takes the opportunity to replace them with
the byte-based bdrv_pread() / bdrv_pwrite().
Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: 43590976f730501688096cff103f2923b72b0f32.1517840877.git.berto@igalia.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
Adding support for L2 slices to expand_zero_clusters_in_l1() needs
(among other things) an extra loop that iterates over all slices of
each L2 table.
Putting all changes in one patch would make it hard to read because
all semantic changes would be mixed with pure indentation changes.
To make things easier this patch simply creates a new block and
changes the indentation of all lines of code inside it. Thus, all
modifications in this patch are cosmetic. There are no semantic
changes and no variables are renamed yet. The next patch will take
care of that.
Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: c2ae9f31ed5b6e591477ad4654448badd1c89d73.1517840877.git.berto@igalia.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
At the moment it doesn't really make a difference whether we call
qcow2_get_refcount() before of after reading the L2 table, but if we
want to support L2 slices we'll need to read the refcount first.
This patch simply changes the order of those two operations to prepare
for that. The patch with the actual semantic changes will be easier to
read because of this.
Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: 947a91d934053a2dbfef979aeb9568f57ef57c5d.1517840877.git.berto@igalia.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
qcow2_update_snapshot_refcount() increases the refcount of all
clusters of a given snapshot. In order to do that it needs to load all
its L2 tables and iterate over their entries. Since we'll be loading
L2 slices instead of full tables we need to add an extra loop that
iterates over all slices of each L2 table.
This function doesn't need any additional changes so apart from that
this patch simply updates the variable name from l2_table to l2_slice.
Signed-off-by: Alberto Garcia <berto@igalia.com>
Message-id: 5f4db199b9637f4833b58487135124d70add8cf0.1517840877.git.berto@igalia.com
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
Adding support for L2 slices to qcow2_update_snapshot_refcount() needs
(among other things) an extra loop that iterates over all slices of
each L2 table.
Putting all changes in one patch would make it hard to read because
all semantic changes would be mixed with pure indentation changes.
To make things easier this patch simply creates a new block and
changes the indentation of all lines of code inside it. Thus, all
modifications in this patch are cosmetic. There are no semantic
changes and no variables are renamed yet. The next patch will take
care of that.
Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: 8ffaa5e55bd51121f80e498f4045b64902a94293.1517840877.git.berto@igalia.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
zero_single_l2() limits the number of clusters to be zeroed to the
amount that fits inside an L2 table. Since we'll be loading L2 slices
instead of full tables we need to update that limit. The function is
renamed to zero_in_l2_slice() for clarity.
Apart from that, this function doesn't need any additional changes, so
this patch simply updates the variable name from l2_table to l2_slice.
Signed-off-by: Alberto Garcia <berto@igalia.com>
Message-id: ebc16e7e79fa6969d8975ef487d679794de4fbcc.1517840877.git.berto@igalia.com
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
discard_single_l2() limits the number of clusters to be discarded
to the amount that fits inside an L2 table. Since we'll be loading
L2 slices instead of full tables we need to update that limit. The
function is renamed to discard_in_l2_slice() for clarity.
Apart from that, this function doesn't need any additional changes, so
this patch simply updates the variable name from l2_table to l2_slice.
Signed-off-by: Alberto Garcia <berto@igalia.com>
Message-id: 1cb44a5b68be5334cb01b97a3db3a3c5a43396e5.1517840877.git.berto@igalia.com
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
handle_alloc() loads an L2 table and limits the number of checked
clusters to the amount that fits inside that table. Since we'll be
loading L2 slices instead of full tables we need to update that limit.
Apart from that, this function doesn't need any additional changes, so
this patch simply updates the variable name from l2_table to l2_slice.
Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: b243299c7136f7014c5af51665431ddbf5e99afd.1517840877.git.berto@igalia.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
handle_copied() loads an L2 table and limits the number of checked
clusters to the amount that fits inside that table. Since we'll be
loading L2 slices instead of full tables we need to update that limit.
Apart from that, this function doesn't need any additional changes, so
this patch simply updates the variable name from l2_table to l2_slice.
Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: 541ac001a7d6b86bab2392554bee53c2b312148c.1517840877.git.berto@igalia.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
There's a loop in this function that iterates over the L2 entries in a
table, so now we need to assert that it remains within the limits of
an L2 slice.
Apart from that, this function doesn't need any additional changes, so
this patch simply updates the variable name from l2_table to l2_slice.
Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: f9846a1c2efc51938e877e2a25852d9ab14797ff.1517840877.git.berto@igalia.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
qcow2_get_cluster_offset() checks how many contiguous bytes are
available at a given offset. The returned number of bytes is limited
by the amount that can be addressed without having to load more than
one L2 table.
Since we'll be loading L2 slices instead of full tables this patch
changes the limit accordingly using the size of the L2 slice for the
calculations instead of the full table size.
One consequence of this is that with small L2 slices operations such
as 'qemu-img map' will need to iterate in more steps because each
qcow2_get_cluster_offset() call will potentially return a smaller
number. However the code is already prepared for that so this doesn't
break semantics.
The l2_table variable is also renamed to l2_slice to reflect this, and
offset_to_l2_index() is replaced with offset_to_l2_slice_index().
Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: 6b602260acb33da56ed6af9611731cb7acd110eb.1517840877.git.berto@igalia.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
This patch updates get_cluster_table() to return L2 slices instead of
full L2 tables.
The code itself needs almost no changes, it only needs to call
offset_to_l2_slice_index() instead of offset_to_l2_index(). This patch
also renames all the relevant variables and the documentation.
Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: 64cf064c0021ba315d3f3032da0f95db1b615f33.1517840877.git.berto@igalia.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
After the previous patch we're now always using l2_load() in
get_cluster_table() regardless of whether a new L2 table has to be
allocated or not.
This patch refactors that part of the code to use one single l2_load()
call.
Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: ce31758c4a1fadccea7a6ccb93951eb01d95fd4c.1517840877.git.berto@igalia.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
This patch updates l2_allocate() to support the qcow2 cache returning
L2 slices instead of full L2 tables.
The old code simply gets an L2 table from the cache and initializes it
with zeroes or with the contents of an existing table. With a cache
that returns slices instead of tables the idea remains the same, but
the code must now iterate over all the slices that are contained in an
L2 table.
Since now we're operating with slices the function can no longer
return the newly-allocated table, so it's up to the caller to retrieve
the appropriate L2 slice after calling l2_allocate() (note that with
this patch the caller is still loading full L2 tables, but we'll deal
with that in a separate patch).
Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-id: 20fc0415bf0e011e29f6487ec86eb06a11f37445.1517840877.git.berto@igalia.com
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
Adding support for L2 slices to l2_allocate() needs (among other
things) an extra loop that iterates over all slices of a new L2 table.
Putting all changes in one patch would make it hard to read because
all semantic changes would be mixed with pure indentation changes.
To make things easier this patch simply creates a new block and
changes the indentation of all lines of code inside it. Thus, all
modifications in this patch are cosmetic. There are no semantic
changes and no variables are renamed yet. The next patch will take
care of that.
Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: d0d7dca8520db304524f52f49d8157595a707a35.1517840877.git.berto@igalia.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
Each entry in the qcow2 L2 cache stores a full L2 table (which uses a
complete cluster in the qcow2 image). A cluster is usually too large
to be used efficiently as the size for a cache entry, so we want to
decouple both values by allowing smaller cache entries. Therefore the
qcow2 L2 cache will no longer return full L2 tables but slices
instead.
This patch updates l2_load() so it can handle L2 slices correctly.
Apart from the offset of the L2 table (which we already had) we also
need the guest offset in order to calculate which one of the slices
we need.
An L2 slice has currently the same size as an L2 table (one cluster),
so for now this function will load exactly the same data as before.
This patch also removes a stale comment about the return value being
a pointer to the L2 table. This function returns an error code since
55c17e9821.
Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: b830aa1fc5b6f8e3cb331d006853fe22facca847.1517840877.git.berto@igalia.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
Similar to offset_to_l2_index(), this function takes a guest offset
and returns the index in the L2 slice that contains its L2 entry.
An L2 slice has currently the same size as an L2 table (one cluster),
so both functions return the same value for now.
Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: a1c45c5c5a76146dd1712d8d1e7b409ad539c718.1517840877.git.berto@igalia.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
The BDRVQcow2State structure contains an l2_size field, which stores
the number of 64-bit entries in an L2 table.
For efficiency reasons we want to be able to load slices instead of
full L2 tables, so we need to know how many entries an L2 slice can
hold.
An L2 slice is the portion of an L2 table that is loaded by the qcow2
cache. At the moment that cache can only load complete tables,
therefore an L2 slice has the same size as an L2 table (one cluster)
and l2_size == l2_slice_size.
Later we'll allow smaller slices, but until then we have to use this
new l2_slice_size field to make the rest of the code ready for that.
Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: adb048595f9fb5dfb110c802a8b3c3be3b937f37.1517840877.git.berto@igalia.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
Similar to offset_to_l2_index(), this function returns the index in
the L1 table for a given guest offset. This is only used in a couple
of places and it's not a particularly complex calculation, but it
makes the code a bit more readable.
Although in the qcow2_get_cluster_offset() case the old code was
taking advantage of the l1_bits variable, we're going to get rid of
the other uses of l1_bits in a later patch anyway, so it doesn't make
sense to keep it just for this.
Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: a5f626fed526b7459a0425fad06d823d18df8522.1517840877.git.berto@igalia.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
This function was only using the BlockDriverState parameter to pass it
to qcow2_cache_get_table_addr(). This is no longer necessary so this
parameter can be removed.
Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: eb0ed90affcf302e5a954bafb5931b5215483d3a.1517840877.git.berto@igalia.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
This function was only using the BlockDriverState parameter to pass it
to qcow2_cache_get_table_idx() and qcow2_cache_table_release(). This
is no longer necessary so this parameter can be removed.
Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: 9724f7e38e763ad3be32627c6b7fe8df9edb1476.1517840877.git.berto@igalia.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
This function was only using the BlockDriverState parameter to pass it
to qcow2_cache_table_release(). This is no longer necessary so this
parameter can be removed.
Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: b74f17591af52f201de0ea3a3b2dd0a81932334d.1517840876.git.berto@igalia.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
This function was never using the BlockDriverState parameter so it can
be safely removed.
Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: 49c74fe8b3aead9056e61a85b145ce787d06262b.1517840876.git.berto@igalia.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
This function was only using the BlockDriverState parameter to pass it
to qcow2_cache_get_table_idx(). This is no longer necessary so this
parameter can be removed.
Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: 6f98155489054a457563da77cdad1a66ebb3e896.1517840876.git.berto@igalia.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
This function was only using the BlockDriverState parameter to pass it
to qcow2_cache_get_table_idx(). This is no longer necessary so this
parameter can be removed.
Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: 5c40516a91782b083c1428b7b6a41bb9e2679bfb.1517840876.git.berto@igalia.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
This function was only using the BlockDriverState parameter to get the
cache table size (since it was equal to the cluster size). This is no
longer necessary so this parameter can be removed.
Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: 7c1b262344375d52544525f85bbbf0548d5ba575.1517840876.git.berto@igalia.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
This function was only using the BlockDriverState parameter to get the
cache table size (since it was equal to the cluster size). This is no
longer necessary so this parameter can be removed.
Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: da3575d47c9a181a2cfd4715e53dd84a2c651017.1517840876.git.berto@igalia.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
This function was only using the BlockDriverState parameter to get the
cache table size (since it was equal to the cluster size). This is no
longer necessary so this parameter can be removed.
Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: e1f943a9e89e1deb876f45de1bb22419ccdb6ad3.1517840876.git.berto@igalia.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
The table size in the qcow2 cache is currently equal to the cluster
size. This doesn't allow us to use the cache memory efficiently,
particularly with large cluster sizes, so we need to be able to have
smaller cache tables that are independent from the cluster size. This
patch adds a new field to Qcow2Cache that we can use instead of the
cluster size.
The current table size is still being initialized to the cluster size,
so there are no semantic changes yet, but this patch will allow us to
prepare the rest of the code and simplify a few function calls.
Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: 67a1bf9e55f417005c567bead95a018dc34bc687.1517840876.git.berto@igalia.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
This function has not been returning the offset of the L2 table since
commit 3948d1d487
Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: b498733b6706a859a03678d74ecbd26aeba129aa.1517840876.git.berto@igalia.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
To maintain load/store disabled bitmap there is new approach:
- deprecate @autoload flag of block-dirty-bitmap-add, make it ignored
- store enabled bitmaps as "auto" to qcow2
- store disabled bitmaps without "auto" flag to qcow2
- on qcow2 open load "auto" bitmaps as enabled and others
as disabled (except in_use bitmaps)
Also, adjust iotests 165 and 176 appropriately.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-id: 20180202160752.143796-1-vsementsov@virtuozzo.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
sd_prealloc() will now preallocate the area [old_size, new_size). As
before, it rounds to buf_size and may thus overshoot and preallocate
areas that were not requested to be preallocated. For image creation,
this is no change in behavior. For truncation, this is in accordance
with the documentation for preallocated truncation.
Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
We want to use this function in sd_truncate() later on, so taking a
filename is not exactly ideal.
Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
By using qemu_do_cluster_truncate() in qemu_cluster_truncate(), we now
automatically have preallocated truncation.
Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Instead of expecting the current size to be 0, query it and allocate
only the area [current_size, offset) if preallocation is requested.
Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Pull out the truncation code from the qemu_cluster_create() function so
we can later reuse it in qemu_gluster_truncate().
Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
glfs_close() is a classical clean-up operation, as can be seen by the
fact that it is executed even if the truncation before it failed.
Also, moving it to clean-up makes it more clear that if it fails, we do
not want it to overwrite the current ret value if that signifies an
error already.
Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
g_realloc() aborts the program if it fails to allocate the required
amount of memory. We want to detect that scenario and return an error
instead, so let's use g_try_realloc().
Signed-off-by: Alberto Garcia <berto@igalia.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
We don't need the can_write_zeroes_with_unmap field in
BlockDriverInfo, because it is redundant information with
supported_zero_flags & BDRV_REQ_MAY_UNMAP. Note that
BlockDriverInfo and supported_zero_flags are both per-device
settings, rather than global state about the driver as a
whole, which means one or both of these bits of information
can already be conditional. Let's audit how they were set:
crypto: always setting can_write_ to false is pointless (the
struct starts life zero-initialized), no use of supported_
nbd: just recently fixed to set can_write_ if supported_
includes MAY_UNMAP (thus this commit effectively reverts
bca80059e and solves the problem mentioned there in a more
global way)
file-posix, iscsi, qcow2: can_write_ is conditional, while
supported_ was unconditional; but passing MAY_UNMAP would
fail with ENOTSUP if the condition wasn't met
qed: can_write_ is unconditional, but pwrite_zeroes lacks
support for MAY_UNMAP and supported_ is not set. Perhaps
support can be added later (since it would be similar to
qcow2), but for now claiming false is no real loss
all other drivers: can_write_ is not set, and supported_ is
either unset or a passthrough
Simplify the code by moving the conditional into
supported_zero_flags for all drivers, then dropping the
now-unused BDI field. For callers that relied on
bdrv_can_write_zeroes_with_unmap(), we return the same
per-device settings for drivers that had conditions (no
observable change in behavior there); and can now return
true (instead of false) for drivers that support passthrough
(for example, the commit driver) which gives those drivers
the same fix as nbd just got in bca80059e. For callers that
relied on supported_zero_flags, we now have a few more places
that can avoid a wasted call to pwrite_zeroes() that will
just fail with ENOTSUP.
Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20180126193439.20219-1-eblake@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
qemu-common.h includes qemu/option.h, but most places that include the
former don't actually need the latter. Drop the include, and add it
to the places that actually need it.
While there, drop superfluous includes of both headers, and
separate #include from file comment with a blank line.
This cleanup makes the number of objects depending on qemu/option.h
drop from 4545 (out of 4743) to 284 in my "build everything" tree.
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20180201111846.21846-20-armbru@redhat.com>
[Semantic conflict with commit bdd6a90a9e in block/nvme.c resolved]
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20180201111846.21846-19-armbru@redhat.com>
