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author | Max Reitz <mreitz@redhat.com> | 2017-06-13 22:21:00 +0200 |
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committer | Max Reitz <mreitz@redhat.com> | 2017-07-11 17:45:02 +0200 |
commit | 7bc45dc17265772abe5dd1d4649c7bb42e1c6df1 (patch) | |
tree | 20eb5257447445a6fa7cc1f445f1ff83619a12b1 /block | |
parent | 35d72602ec5709b5078ff0e6361eee57fb652f98 (diff) | |
download | qemu-7bc45dc17265772abe5dd1d4649c7bb42e1c6df1.zip qemu-7bc45dc17265772abe5dd1d4649c7bb42e1c6df1.tar.gz qemu-7bc45dc17265772abe5dd1d4649c7bb42e1c6df1.tar.bz2 |
block/qcow2: Generalize preallocate()
This patch adds two new parameters to the preallocate() function so we
will be able to use it not just for preallocating a new image but also
for preallocated image growth.
The offset parameter allows the caller to specify a virtual offset from
which to start preallocating. For newly created images this is always 0,
but for preallocating growth this will be the old image length.
The new_length parameter specifies the supposed new length of the image
(basically the "end offset" for preallocation). During image truncation,
bdrv_getlength() will return the old image length so we cannot rely on
its return value then.
Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 20170613202107.10125-10-mreitz@redhat.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
Diffstat (limited to 'block')
-rw-r--r-- | block/qcow2.c | 17 |
1 files changed, 12 insertions, 5 deletions
diff --git a/block/qcow2.c b/block/qcow2.c index 0f44780..1ee8452 100644 --- a/block/qcow2.c +++ b/block/qcow2.c @@ -2476,17 +2476,24 @@ static int qcow2_set_up_encryption(BlockDriverState *bs, const char *encryptfmt, } -static int preallocate(BlockDriverState *bs) +/** + * Preallocates metadata structures for data clusters between @offset (in the + * guest disk) and @new_length (which is thus generally the new guest disk + * size). + * + * Returns: 0 on success, -errno on failure. + */ +static int preallocate(BlockDriverState *bs, + uint64_t offset, uint64_t new_length) { uint64_t bytes; - uint64_t offset; uint64_t host_offset = 0; unsigned int cur_bytes; int ret; QCowL2Meta *meta; - bytes = bdrv_getlength(bs); - offset = 0; + assert(offset <= new_length); + bytes = new_length - offset; while (bytes) { cur_bytes = MIN(bytes, INT_MAX); @@ -2830,7 +2837,7 @@ static int qcow2_create2(const char *filename, int64_t total_size, if (prealloc != PREALLOC_MODE_OFF) { BDRVQcow2State *s = blk_bs(blk)->opaque; qemu_co_mutex_lock(&s->lock); - ret = preallocate(blk_bs(blk)); + ret = preallocate(blk_bs(blk), 0, total_size); qemu_co_mutex_unlock(&s->lock); if (ret < 0) { error_setg_errno(errp, -ret, "Could not preallocate metadata"); |