Libguestfs - Nov 2019 - Re: [v2v PATCH] v2v: require 100 availabe inodes on each filesystem (RHBZ#1764569)

Enough free space in a filesystem does not imply available inodes to
create/modify files on that filesystem.  Hence, require at least 100
available inodes on filesystems that can provide inode counts.
---
 v2v/v2v.ml | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/v2v/v2v.ml b/v2v/v2v.ml
index 03590c9e..b5b2da08 100644
--- a/v2v/v2v.ml
+++ b/v2v/v2v.ml
@@ -375,6 +375,8 @@ and print_mpstat chan { mp_dev = dev; mp_path = path;
 (* Conversion can fail if there is no space on the guest filesystems
  * (RHBZ#1139543).  To avoid this situation, check there is some
  * headroom.  Mainly we care about the root filesystem.
+ *
+ * Also make sure filesystems have available inodes. (RHBZ#1764569)
  *)
 and check_guest_free_space mpstats    message (f_"Checking for sufficient
free disk space in the guest");
@@ -399,14 +401,21 @@ and check_guest_free_space mpstats        10_000_000L
   in
 
+  (* Reasonable headroom for conversion operations. *)
+  let needed_inodes = 100L in
+
   List.iter (
-    fun { mp_path; mp_statvfs = { G.bfree; bsize } } ->
+    fun { mp_path; mp_statvfs = { G.bfree; bsize; files; ffree } } ->
       (* bfree = free blocks for root user *)
       let free_bytes = bfree *^ bsize in
       let needed_bytes = needed_bytes_for_mp mp_path in
       if free_bytes < needed_bytes then
         error (f_"not enough free space for conversion on filesystem ‘%s’.
%Ld bytes free < %Ld bytes needed")
-          mp_path free_bytes needed_bytes
+          mp_path free_bytes needed_bytes;
+      (* Not all the filesystems have inode counts. *)
+      if files > 0L && ffree < needed_inodes then
+        error (f_"not enough available inodes for conversion on filesystem
‘%s’.  %Ld inodes available < %Ld inodes needed")
+          mp_path ffree needed_inodes
   ) mpstats
 
 (* Perform the fstrim. *)
-- 
2.21.0

On Wed, Nov 27, 2019 at 06:00:21PM +0100, Pino Toscano
wrote:
> Enough free space in a filesystem does not imply available inodes to
> create/modify files on that filesystem.  Hence, require at least 100
> available inodes on filesystems that can provide inode counts.
> ---
>  v2v/v2v.ml | 13 +++++++++++--
>  1 file changed, 11 insertions(+), 2 deletions(-)
> 
> diff --git a/v2v/v2v.ml b/v2v/v2v.ml
> index 03590c9e..b5b2da08 100644
> --- a/v2v/v2v.ml
> +++ b/v2v/v2v.ml
> @@ -375,6 +375,8 @@ and print_mpstat chan { mp_dev = dev; mp_path = path;
>  (* Conversion can fail if there is no space on the guest filesystems
>   * (RHBZ#1139543).  To avoid this situation, check there is some
>   * headroom.  Mainly we care about the root filesystem.
> + *
> + * Also make sure filesystems have available inodes. (RHBZ#1764569)
>   *)
>  and check_guest_free_space mpstats >    message (f_"Checking for
sufficient free disk space in the guest");
> @@ -399,14 +401,21 @@ and check_guest_free_space mpstats >       
10_000_000L
>    in
>  
> +  (* Reasonable headroom for conversion operations. *)
> +  let needed_inodes = 100L in
> +
>    List.iter (
> -    fun { mp_path; mp_statvfs = { G.bfree; bsize } } ->
> +    fun { mp_path; mp_statvfs = { G.bfree; bsize; files; ffree } } ->
>        (* bfree = free blocks for root user *)
>        let free_bytes = bfree *^ bsize in
>        let needed_bytes = needed_bytes_for_mp mp_path in
>        if free_bytes < needed_bytes then
>          error (f_"not enough free space for conversion on filesystem
‘%s’.  %Ld bytes free < %Ld bytes needed")
> -          mp_path free_bytes needed_bytes
> +          mp_path free_bytes needed_bytes;
> +      (* Not all the filesystems have inode counts. *)
> +      if files > 0L && ffree < needed_inodes then
> +        error (f_"not enough available inodes for conversion on
filesystem ‘%s’.  %Ld inodes available < %Ld inodes needed")
> +          mp_path ffree needed_inodes
>    ) mpstats
Looks good to me, however it does need the documentation updated here:

https://github.com/libguestfs/virt-v2v/blob/master/docs/virt-v2v.pod#free-space-in-the-guest

ACK with docs updated.

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
Read my programming and virtualization blog: http://rwmj.wordpress.com
virt-p2v converts physical machines to virtual machines.  Boot with a
live CD or over the network (PXE) and turn machines into KVM guests.
http://libguestfs.org/virt-v2v

On 11/27/19 11:00 AM, Pino Toscano wrote:

In the subject: s/availabe/available/

also, is it necessary to stick RHBZ#... in the subject, or is that a 
better fit in the commit body?
> Enough free space in a filesystem does not imply available inodes to
> create/modify files on that filesystem.  Hence, require at least 100
> available inodes on filesystems that can provide inode counts.
> ---

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
Virtualization:  qemu.org | libvirt.org

On Wed, Nov 27, 2019 at 01:26:28PM -0600, Eric Blake
wrote:
> On 11/27/19 11:00 AM, Pino Toscano wrote:
> 
> In the subject: s/availabe/available/
> 
> also, is it necessary to stick RHBZ#... in the subject, or is that a
> better fit in the commit body?
I have a script I use for making the release notes that picks the
RHBZ# string from the subject, so this would have to be changed if we
changed this:

https://github.com/libguestfs/libguestfs/blob/master/bugs-in-changelog.sh

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
Read my programming and virtualization blog: http://rwmj.wordpress.com
virt-p2v converts physical machines to virtual machines.  Boot with a
live CD or over the network (PXE) and turn machines into KVM guests.
http://libguestfs.org/virt-v2v