Patchwork [1/2] qemu-img: Fix division by zero for zero size images

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Submitter Kevin Wolf
Date Oct. 12, 2012, 12:31 p.m.
Message ID <1350045069-8500-2-git-send-email-kwolf@redhat.com>
Download mbox | patch
Permalink /patch/191108/
State New
Headers show

Comments

Kevin Wolf - Oct. 12, 2012, 12:31 p.m.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 qemu-img.c |   23 +++++++++++++++--------
 1 files changed, 15 insertions(+), 8 deletions(-)
Paolo Bonzini - Oct. 12, 2012, 4:56 p.m.
Il 12/10/2012 14:31, Kevin Wolf ha scritto:
> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
> ---
>  qemu-img.c |   23 +++++++++++++++--------
>  1 files changed, 15 insertions(+), 8 deletions(-)
> 
> diff --git a/qemu-img.c b/qemu-img.c
> index f17f187..849eb41 100644
> --- a/qemu-img.c
> +++ b/qemu-img.c
> @@ -674,7 +674,7 @@ static int img_convert(int argc, char **argv)
>      QEMUOptionParameter *out_baseimg_param;
>      char *options = NULL;
>      const char *snapshot_name = NULL;
> -    float local_progress;
> +    float local_progress = 0;
>      int min_sparse = 8; /* Need at least 4k of zeros for sparse detection */
>  
>      fmt = NULL;
> @@ -914,8 +914,10 @@ static int img_convert(int argc, char **argv)
>          sector_num = 0;
>  
>          nb_sectors = total_sectors;
> -        local_progress = (float)100 /
> -            (nb_sectors / MIN(nb_sectors, cluster_sectors));
> +        if (nb_sectors != 0) {
> +            local_progress = (float)100 /
> +                (nb_sectors / MIN(nb_sectors, cluster_sectors));
> +        }
>  
>          for(;;) {
>              int64_t bs_num;
> @@ -986,8 +988,10 @@ static int img_convert(int argc, char **argv)
>  
>          sector_num = 0; // total number of sectors converted so far
>          nb_sectors = total_sectors - sector_num;
> -        local_progress = (float)100 /
> -            (nb_sectors / MIN(nb_sectors, IO_BUF_SIZE / 512));
> +        if (nb_sectors != 0) {
> +            local_progress = (float)100 /
> +                (nb_sectors / MIN(nb_sectors, IO_BUF_SIZE / 512));
> +        }
>  
>          for(;;) {
>              nb_sectors = total_sectors - sector_num;
> @@ -1585,7 +1589,7 @@ static int img_rebase(int argc, char **argv)
>          int n;
>          uint8_t * buf_old;
>          uint8_t * buf_new;
> -        float local_progress;
> +        float local_progress = 0;
>  
>          buf_old = qemu_blockalign(bs, IO_BUF_SIZE);
>          buf_new = qemu_blockalign(bs, IO_BUF_SIZE);
> @@ -1594,8 +1598,11 @@ static int img_rebase(int argc, char **argv)
>          bdrv_get_geometry(bs_old_backing, &old_backing_num_sectors);
>          bdrv_get_geometry(bs_new_backing, &new_backing_num_sectors);
>  
> -        local_progress = (float)100 /
> -            (num_sectors / MIN(num_sectors, IO_BUF_SIZE / 512));
> +        if (num_sectors != 0) {
> +            local_progress = (float)100 /
> +                (num_sectors / MIN(num_sectors, IO_BUF_SIZE / 512));
> +        }
> +
>          for (sector = 0; sector < num_sectors; sector += n) {
>  
>              /* How many sectors can we handle with the next read? */
> 

Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>

/me keeps this in mind for reviewing Mirek's qemu-img compare series

Patch

diff --git a/qemu-img.c b/qemu-img.c
index f17f187..849eb41 100644
--- a/qemu-img.c
+++ b/qemu-img.c
@@ -674,7 +674,7 @@  static int img_convert(int argc, char **argv)
     QEMUOptionParameter *out_baseimg_param;
     char *options = NULL;
     const char *snapshot_name = NULL;
-    float local_progress;
+    float local_progress = 0;
     int min_sparse = 8; /* Need at least 4k of zeros for sparse detection */
 
     fmt = NULL;
@@ -914,8 +914,10 @@  static int img_convert(int argc, char **argv)
         sector_num = 0;
 
         nb_sectors = total_sectors;
-        local_progress = (float)100 /
-            (nb_sectors / MIN(nb_sectors, cluster_sectors));
+        if (nb_sectors != 0) {
+            local_progress = (float)100 /
+                (nb_sectors / MIN(nb_sectors, cluster_sectors));
+        }
 
         for(;;) {
             int64_t bs_num;
@@ -986,8 +988,10 @@  static int img_convert(int argc, char **argv)
 
         sector_num = 0; // total number of sectors converted so far
         nb_sectors = total_sectors - sector_num;
-        local_progress = (float)100 /
-            (nb_sectors / MIN(nb_sectors, IO_BUF_SIZE / 512));
+        if (nb_sectors != 0) {
+            local_progress = (float)100 /
+                (nb_sectors / MIN(nb_sectors, IO_BUF_SIZE / 512));
+        }
 
         for(;;) {
             nb_sectors = total_sectors - sector_num;
@@ -1585,7 +1589,7 @@  static int img_rebase(int argc, char **argv)
         int n;
         uint8_t * buf_old;
         uint8_t * buf_new;
-        float local_progress;
+        float local_progress = 0;
 
         buf_old = qemu_blockalign(bs, IO_BUF_SIZE);
         buf_new = qemu_blockalign(bs, IO_BUF_SIZE);
@@ -1594,8 +1598,11 @@  static int img_rebase(int argc, char **argv)
         bdrv_get_geometry(bs_old_backing, &old_backing_num_sectors);
         bdrv_get_geometry(bs_new_backing, &new_backing_num_sectors);
 
-        local_progress = (float)100 /
-            (num_sectors / MIN(num_sectors, IO_BUF_SIZE / 512));
+        if (num_sectors != 0) {
+            local_progress = (float)100 /
+                (num_sectors / MIN(num_sectors, IO_BUF_SIZE / 512));
+        }
+
         for (sector = 0; sector < num_sectors; sector += n) {
 
             /* How many sectors can we handle with the next read? */