diff mbox

[v12,6/6] qcow2: Add falloc and full preallocation option

Message ID aaecb3fcf30e6b54515270dda05f7271d6896e72.1405058453.git.hutao@cn.fujitsu.com
State New
Headers show

Commit Message

Hu Tao July 11, 2014, 6:10 a.m. UTC 
This adds preallocation=falloc and preallocation=full mode to qcow2
image creation.

preallocation=full allocates disk space by writing zeros to disk to
ensure disk space in any cases.

preallocation=falloc likes preallocation=full, but allocates disk space
by posix_fallocate().

Signed-off-by: Hu Tao <hutao@cn.fujitsu.com>
---
 block/qcow2.c              | 31 ++++++++++++++++++++++++--
 tests/qemu-iotests/082.out | 54 +++++++++++++++++++++++-----------------------
 2 files changed, 56 insertions(+), 29 deletions(-)

Comments

Max Reitz July 11, 2014, 9:07 p.m. UTC | #1 
On 11.07.2014 08:10, Hu Tao wrote:
> This adds preallocation=falloc and preallocation=full mode to qcow2
> image creation.
>
> preallocation=full allocates disk space by writing zeros to disk to
> ensure disk space in any cases.
>
> preallocation=falloc likes preallocation=full, but allocates disk space
> by posix_fallocate().
>
> Signed-off-by: Hu Tao <hutao@cn.fujitsu.com>
> ---
>   block/qcow2.c              | 31 ++++++++++++++++++++++++--
>   tests/qemu-iotests/082.out | 54 +++++++++++++++++++++++-----------------------
>   2 files changed, 56 insertions(+), 29 deletions(-)

Reviewed-by: Max Reitz <mreitz@redhat.com>
Kevin Wolf Aug. 22, 2014, 11 a.m. UTC | #2 
Am 11.07.2014 um 08:10 hat Hu Tao geschrieben:
> This adds preallocation=falloc and preallocation=full mode to qcow2
> image creation.
> 
> preallocation=full allocates disk space by writing zeros to disk to
> ensure disk space in any cases.
> 
> preallocation=falloc likes preallocation=full, but allocates disk space
> by posix_fallocate().
> 
> Signed-off-by: Hu Tao <hutao@cn.fujitsu.com>
> ---
>  block/qcow2.c              | 31 ++++++++++++++++++++++++--
>  tests/qemu-iotests/082.out | 54 +++++++++++++++++++++++-----------------------
>  2 files changed, 56 insertions(+), 29 deletions(-)
> 
> diff --git a/block/qcow2.c b/block/qcow2.c
> index cfba93b..f48e915 100644
> --- a/block/qcow2.c
> +++ b/block/qcow2.c
> @@ -1593,6 +1593,9 @@ static int preallocate(BlockDriverState *bs)
>      return 0;
>  }
>  
> +static uint64_t minimal_blob_size(uint64_t ts, int cb, int spcb,
> +                                  uint64_t overhead);
> +
>  static int qcow2_create2(const char *filename, int64_t total_size,
>                           const char *backing_file, const char *backing_format,
>                           int flags, size_t cluster_size, PreallocMode prealloc,
> @@ -1628,6 +1631,29 @@ static int qcow2_create2(const char *filename, int64_t total_size,
>      Error *local_err = NULL;
>      int ret;
>  
> +    if (prealloc == PREALLOC_MODE_FULL || prealloc == PREALLOC_MODE_FALLOC) {
> +        int64_t meta_size = 0;
> +        uint64_t nl2e;
> +
> +        total_size = align_offset(total_size, cluster_size);

I don't think it's a good idea to let the virtual disk size depend on
whether preallocation is enabled or not. You should always get the same
rounding (which is rounding up to the next sector boundary).

Do you need full clusters for your calculations below or what is this
good for? If so, please use a local variable and leave the value used
for the bdrv_truncate() call unmodified.

> +        /* total size of L2 tables */
> +        nl2e = total_size >> cluster_bits;
> +        nl2e = align_offset(nl2e, cluster_size / sizeof(uint64_t));
> +        uint64_t l2_clusters = nl2e * sizeof(uint64_t) >> cluster_bits;
> +
> +        meta_size =
> +            (1 +
> +             minimal_blob_size(total_size >> BDRV_SECTOR_BITS,
> +                               cluster_bits, cluster_bits - BDRV_SECTOR_BITS,
> +                               1 + l2_clusters +
> +                               (total_size >> cluster_bits)) +
> +             l2_clusters) << cluster_bits;
> +
> +        qemu_opt_set_number(opts, BLOCK_OPT_SIZE, total_size + meta_size);
> +        qemu_opt_set(opts, BLOCK_OPT_PREALLOC, PreallocMode_lookup[prealloc]);
> +    }
> +
>      ret = bdrv_create_file(filename, opts, &local_err);
>      if (ret < 0) {
>          error_propagate(errp, local_err);

Kevin
Hu Tao Aug. 25, 2014, 1:36 a.m. UTC | #3 
On Fri, Aug 22, 2014 at 01:00:53PM +0200, Kevin Wolf wrote:
> Am 11.07.2014 um 08:10 hat Hu Tao geschrieben:
> > This adds preallocation=falloc and preallocation=full mode to qcow2
> > image creation.
> > 
> > preallocation=full allocates disk space by writing zeros to disk to
> > ensure disk space in any cases.
> > 
> > preallocation=falloc likes preallocation=full, but allocates disk space
> > by posix_fallocate().
> > 
> > Signed-off-by: Hu Tao <hutao@cn.fujitsu.com>
> > ---
> >  block/qcow2.c              | 31 ++++++++++++++++++++++++--
> >  tests/qemu-iotests/082.out | 54 +++++++++++++++++++++++-----------------------
> >  2 files changed, 56 insertions(+), 29 deletions(-)
> > 
> > diff --git a/block/qcow2.c b/block/qcow2.c
> > index cfba93b..f48e915 100644
> > --- a/block/qcow2.c
> > +++ b/block/qcow2.c
> > @@ -1593,6 +1593,9 @@ static int preallocate(BlockDriverState *bs)
> >      return 0;
> >  }
> >  
> > +static uint64_t minimal_blob_size(uint64_t ts, int cb, int spcb,
> > +                                  uint64_t overhead);
> > +
> >  static int qcow2_create2(const char *filename, int64_t total_size,
> >                           const char *backing_file, const char *backing_format,
> >                           int flags, size_t cluster_size, PreallocMode prealloc,
> > @@ -1628,6 +1631,29 @@ static int qcow2_create2(const char *filename, int64_t total_size,
> >      Error *local_err = NULL;
> >      int ret;
> >  
> > +    if (prealloc == PREALLOC_MODE_FULL || prealloc == PREALLOC_MODE_FALLOC) {
> > +        int64_t meta_size = 0;
> > +        uint64_t nl2e;
> > +
> > +        total_size = align_offset(total_size, cluster_size);
> 
> I don't think it's a good idea to let the virtual disk size depend on
> whether preallocation is enabled or not. You should always get the same
> rounding (which is rounding up to the next sector boundary).
> 
> Do you need full clusters for your calculations below or what is this
> good for? If so, please use a local variable and leave the value used
> for the bdrv_truncate() call unmodified.

Yes, it is for the calculation. I'll use a local variable for it.

Regards,
Hu
diff mbox

Patch

diff --git a/block/qcow2.c b/block/qcow2.c
index cfba93b..f48e915 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -1593,6 +1593,9 @@  static int preallocate(BlockDriverState *bs)
     return 0;
 }
 
+static uint64_t minimal_blob_size(uint64_t ts, int cb, int spcb,
+                                  uint64_t overhead);
+
 static int qcow2_create2(const char *filename, int64_t total_size,
                          const char *backing_file, const char *backing_format,
                          int flags, size_t cluster_size, PreallocMode prealloc,
@@ -1628,6 +1631,29 @@  static int qcow2_create2(const char *filename, int64_t total_size,
     Error *local_err = NULL;
     int ret;
 
+    if (prealloc == PREALLOC_MODE_FULL || prealloc == PREALLOC_MODE_FALLOC) {
+        int64_t meta_size = 0;
+        uint64_t nl2e;
+
+        total_size = align_offset(total_size, cluster_size);
+
+        /* total size of L2 tables */
+        nl2e = total_size >> cluster_bits;
+        nl2e = align_offset(nl2e, cluster_size / sizeof(uint64_t));
+        uint64_t l2_clusters = nl2e * sizeof(uint64_t) >> cluster_bits;
+
+        meta_size =
+            (1 +
+             minimal_blob_size(total_size >> BDRV_SECTOR_BITS,
+                               cluster_bits, cluster_bits - BDRV_SECTOR_BITS,
+                               1 + l2_clusters +
+                               (total_size >> cluster_bits)) +
+             l2_clusters) << cluster_bits;
+
+        qemu_opt_set_number(opts, BLOCK_OPT_SIZE, total_size + meta_size);
+        qemu_opt_set(opts, BLOCK_OPT_PREALLOC, PreallocMode_lookup[prealloc]);
+    }
+
     ret = bdrv_create_file(filename, opts, &local_err);
     if (ret < 0) {
         error_propagate(errp, local_err);
@@ -1733,7 +1759,7 @@  static int qcow2_create2(const char *filename, int64_t total_size,
     }
 
     /* And if we're supposed to preallocate metadata, do that now */
-    if (prealloc) {
+    if (prealloc != PREALLOC_MODE_OFF) {
         BDRVQcowState *s = bs->opaque;
         qemu_co_mutex_lock(&s->lock);
         ret = preallocate(bs);
@@ -2760,7 +2786,8 @@  static QemuOptsList qcow2_create_opts = {
         {
             .name = BLOCK_OPT_PREALLOC,
             .type = QEMU_OPT_STRING,
-            .help = "Preallocation mode (allowed values: off, metadata)"
+            .help = "Preallocation mode (allowed values: off, metadata, "
+                    "falloc, full)"
         },
         {
             .name = BLOCK_OPT_LAZY_REFCOUNTS,
diff --git a/tests/qemu-iotests/082.out b/tests/qemu-iotests/082.out
index 413e7ef..90c21c8 100644
--- a/tests/qemu-iotests/082.out
+++ b/tests/qemu-iotests/082.out
@@ -64,7 +64,7 @@  backing_file     File name of a base image
 backing_fmt      Image format of the base image
 encryption       Encrypt the image
 cluster_size     qcow2 cluster size
-preallocation    Preallocation mode (allowed values: off, metadata)
+preallocation    Preallocation mode (allowed values: off, metadata, falloc, full)
 lazy_refcounts   Postpone refcount updates
 nocow            Turn off copy-on-write (valid only on btrfs)
 
@@ -76,7 +76,7 @@  backing_file     File name of a base image
 backing_fmt      Image format of the base image
 encryption       Encrypt the image
 cluster_size     qcow2 cluster size
-preallocation    Preallocation mode (allowed values: off, metadata)
+preallocation    Preallocation mode (allowed values: off, metadata, falloc, full)
 lazy_refcounts   Postpone refcount updates
 nocow            Turn off copy-on-write (valid only on btrfs)
 
@@ -88,7 +88,7 @@  backing_file     File name of a base image
 backing_fmt      Image format of the base image
 encryption       Encrypt the image
 cluster_size     qcow2 cluster size
-preallocation    Preallocation mode (allowed values: off, metadata)
+preallocation    Preallocation mode (allowed values: off, metadata, falloc, full)
 lazy_refcounts   Postpone refcount updates
 nocow            Turn off copy-on-write (valid only on btrfs)
 
@@ -100,7 +100,7 @@  backing_file     File name of a base image
 backing_fmt      Image format of the base image
 encryption       Encrypt the image
 cluster_size     qcow2 cluster size
-preallocation    Preallocation mode (allowed values: off, metadata)
+preallocation    Preallocation mode (allowed values: off, metadata, falloc, full)
 lazy_refcounts   Postpone refcount updates
 nocow            Turn off copy-on-write (valid only on btrfs)
 
@@ -112,7 +112,7 @@  backing_file     File name of a base image
 backing_fmt      Image format of the base image
 encryption       Encrypt the image
 cluster_size     qcow2 cluster size
-preallocation    Preallocation mode (allowed values: off, metadata)
+preallocation    Preallocation mode (allowed values: off, metadata, falloc, full)
 lazy_refcounts   Postpone refcount updates
 nocow            Turn off copy-on-write (valid only on btrfs)
 
@@ -124,7 +124,7 @@  backing_file     File name of a base image
 backing_fmt      Image format of the base image
 encryption       Encrypt the image
 cluster_size     qcow2 cluster size
-preallocation    Preallocation mode (allowed values: off, metadata)
+preallocation    Preallocation mode (allowed values: off, metadata, falloc, full)
 lazy_refcounts   Postpone refcount updates
 nocow            Turn off copy-on-write (valid only on btrfs)
 
@@ -136,7 +136,7 @@  backing_file     File name of a base image
 backing_fmt      Image format of the base image
 encryption       Encrypt the image
 cluster_size     qcow2 cluster size
-preallocation    Preallocation mode (allowed values: off, metadata)
+preallocation    Preallocation mode (allowed values: off, metadata, falloc, full)
 lazy_refcounts   Postpone refcount updates
 nocow            Turn off copy-on-write (valid only on btrfs)
 
@@ -148,7 +148,7 @@  backing_file     File name of a base image
 backing_fmt      Image format of the base image
 encryption       Encrypt the image
 cluster_size     qcow2 cluster size
-preallocation    Preallocation mode (allowed values: off, metadata)
+preallocation    Preallocation mode (allowed values: off, metadata, falloc, full)
 lazy_refcounts   Postpone refcount updates
 nocow            Turn off copy-on-write (valid only on btrfs)
 
@@ -175,7 +175,7 @@  backing_file     File name of a base image
 backing_fmt      Image format of the base image
 encryption       Encrypt the image
 cluster_size     qcow2 cluster size
-preallocation    Preallocation mode (allowed values: off, metadata)
+preallocation    Preallocation mode (allowed values: off, metadata, falloc, full)
 lazy_refcounts   Postpone refcount updates
 
 Testing: create -o help
@@ -253,7 +253,7 @@  backing_file     File name of a base image
 backing_fmt      Image format of the base image
 encryption       Encrypt the image
 cluster_size     qcow2 cluster size
-preallocation    Preallocation mode (allowed values: off, metadata)
+preallocation    Preallocation mode (allowed values: off, metadata, falloc, full)
 lazy_refcounts   Postpone refcount updates
 nocow            Turn off copy-on-write (valid only on btrfs)
 
@@ -265,7 +265,7 @@  backing_file     File name of a base image
 backing_fmt      Image format of the base image
 encryption       Encrypt the image
 cluster_size     qcow2 cluster size
-preallocation    Preallocation mode (allowed values: off, metadata)
+preallocation    Preallocation mode (allowed values: off, metadata, falloc, full)
 lazy_refcounts   Postpone refcount updates
 nocow            Turn off copy-on-write (valid only on btrfs)
 
@@ -277,7 +277,7 @@  backing_file     File name of a base image
 backing_fmt      Image format of the base image
 encryption       Encrypt the image
 cluster_size     qcow2 cluster size
-preallocation    Preallocation mode (allowed values: off, metadata)
+preallocation    Preallocation mode (allowed values: off, metadata, falloc, full)
 lazy_refcounts   Postpone refcount updates
 nocow            Turn off copy-on-write (valid only on btrfs)
 
@@ -289,7 +289,7 @@  backing_file     File name of a base image
 backing_fmt      Image format of the base image
 encryption       Encrypt the image
 cluster_size     qcow2 cluster size
-preallocation    Preallocation mode (allowed values: off, metadata)
+preallocation    Preallocation mode (allowed values: off, metadata, falloc, full)
 lazy_refcounts   Postpone refcount updates
 nocow            Turn off copy-on-write (valid only on btrfs)
 
@@ -301,7 +301,7 @@  backing_file     File name of a base image
 backing_fmt      Image format of the base image
 encryption       Encrypt the image
 cluster_size     qcow2 cluster size
-preallocation    Preallocation mode (allowed values: off, metadata)
+preallocation    Preallocation mode (allowed values: off, metadata, falloc, full)
 lazy_refcounts   Postpone refcount updates
 nocow            Turn off copy-on-write (valid only on btrfs)
 
@@ -313,7 +313,7 @@  backing_file     File name of a base image
 backing_fmt      Image format of the base image
 encryption       Encrypt the image
 cluster_size     qcow2 cluster size
-preallocation    Preallocation mode (allowed values: off, metadata)
+preallocation    Preallocation mode (allowed values: off, metadata, falloc, full)
 lazy_refcounts   Postpone refcount updates
 nocow            Turn off copy-on-write (valid only on btrfs)
 
@@ -325,7 +325,7 @@  backing_file     File name of a base image
 backing_fmt      Image format of the base image
 encryption       Encrypt the image
 cluster_size     qcow2 cluster size
-preallocation    Preallocation mode (allowed values: off, metadata)
+preallocation    Preallocation mode (allowed values: off, metadata, falloc, full)
 lazy_refcounts   Postpone refcount updates
 nocow            Turn off copy-on-write (valid only on btrfs)
 
@@ -337,7 +337,7 @@  backing_file     File name of a base image
 backing_fmt      Image format of the base image
 encryption       Encrypt the image
 cluster_size     qcow2 cluster size
-preallocation    Preallocation mode (allowed values: off, metadata)
+preallocation    Preallocation mode (allowed values: off, metadata, falloc, full)
 lazy_refcounts   Postpone refcount updates
 nocow            Turn off copy-on-write (valid only on btrfs)
 
@@ -364,7 +364,7 @@  backing_file     File name of a base image
 backing_fmt      Image format of the base image
 encryption       Encrypt the image
 cluster_size     qcow2 cluster size
-preallocation    Preallocation mode (allowed values: off, metadata)
+preallocation    Preallocation mode (allowed values: off, metadata, falloc, full)
 lazy_refcounts   Postpone refcount updates
 
 Testing: convert -o help
@@ -431,7 +431,7 @@  backing_file     File name of a base image
 backing_fmt      Image format of the base image
 encryption       Encrypt the image
 cluster_size     qcow2 cluster size
-preallocation    Preallocation mode (allowed values: off, metadata)
+preallocation    Preallocation mode (allowed values: off, metadata, falloc, full)
 lazy_refcounts   Postpone refcount updates
 nocow            Turn off copy-on-write (valid only on btrfs)
 
@@ -443,7 +443,7 @@  backing_file     File name of a base image
 backing_fmt      Image format of the base image
 encryption       Encrypt the image
 cluster_size     qcow2 cluster size
-preallocation    Preallocation mode (allowed values: off, metadata)
+preallocation    Preallocation mode (allowed values: off, metadata, falloc, full)
 lazy_refcounts   Postpone refcount updates
 nocow            Turn off copy-on-write (valid only on btrfs)
 
@@ -455,7 +455,7 @@  backing_file     File name of a base image
 backing_fmt      Image format of the base image
 encryption       Encrypt the image
 cluster_size     qcow2 cluster size
-preallocation    Preallocation mode (allowed values: off, metadata)
+preallocation    Preallocation mode (allowed values: off, metadata, falloc, full)
 lazy_refcounts   Postpone refcount updates
 nocow            Turn off copy-on-write (valid only on btrfs)
 
@@ -467,7 +467,7 @@  backing_file     File name of a base image
 backing_fmt      Image format of the base image
 encryption       Encrypt the image
 cluster_size     qcow2 cluster size
-preallocation    Preallocation mode (allowed values: off, metadata)
+preallocation    Preallocation mode (allowed values: off, metadata, falloc, full)
 lazy_refcounts   Postpone refcount updates
 nocow            Turn off copy-on-write (valid only on btrfs)
 
@@ -479,7 +479,7 @@  backing_file     File name of a base image
 backing_fmt      Image format of the base image
 encryption       Encrypt the image
 cluster_size     qcow2 cluster size
-preallocation    Preallocation mode (allowed values: off, metadata)
+preallocation    Preallocation mode (allowed values: off, metadata, falloc, full)
 lazy_refcounts   Postpone refcount updates
 nocow            Turn off copy-on-write (valid only on btrfs)
 
@@ -491,7 +491,7 @@  backing_file     File name of a base image
 backing_fmt      Image format of the base image
 encryption       Encrypt the image
 cluster_size     qcow2 cluster size
-preallocation    Preallocation mode (allowed values: off, metadata)
+preallocation    Preallocation mode (allowed values: off, metadata, falloc, full)
 lazy_refcounts   Postpone refcount updates
 nocow            Turn off copy-on-write (valid only on btrfs)
 
@@ -503,7 +503,7 @@  backing_file     File name of a base image
 backing_fmt      Image format of the base image
 encryption       Encrypt the image
 cluster_size     qcow2 cluster size
-preallocation    Preallocation mode (allowed values: off, metadata)
+preallocation    Preallocation mode (allowed values: off, metadata, falloc, full)
 lazy_refcounts   Postpone refcount updates
 nocow            Turn off copy-on-write (valid only on btrfs)
 
@@ -515,7 +515,7 @@  backing_file     File name of a base image
 backing_fmt      Image format of the base image
 encryption       Encrypt the image
 cluster_size     qcow2 cluster size
-preallocation    Preallocation mode (allowed values: off, metadata)
+preallocation    Preallocation mode (allowed values: off, metadata, falloc, full)
 lazy_refcounts   Postpone refcount updates
 nocow            Turn off copy-on-write (valid only on btrfs)
 
@@ -544,7 +544,7 @@  backing_file     File name of a base image
 backing_fmt      Image format of the base image
 encryption       Encrypt the image
 cluster_size     qcow2 cluster size
-preallocation    Preallocation mode (allowed values: off, metadata)
+preallocation    Preallocation mode (allowed values: off, metadata, falloc, full)
 lazy_refcounts   Postpone refcount updates
 
 Testing: convert -o help