[pve-devel] [PATCH pve-storage v1 3/3] plugin: improve error handling when creating a content subdir fails

[Max R. Carrara]

Wrap the call to `mkpath` in an `eval` and add some additional context
to the error message, namely that creating the content directory for a
given vtype failed.

Handle "Permission denied" and "Read-only file system" errors
separately and tell the user to ensure that the storage has read and
write access when such errors occurs.

Do all this with the help of an anonymous subroutine, because the body
inside the loop would otherwise get a little convoluted / hard to
parse. Also, use the `/x` flag for the regexes to make them a tiny bit
easier to read.

Spotted in the community forum:
https://forum.proxmox.com/threads/bug-creating-nfs-volume-storage.177354/

Signed-off-by: Max R. Carrara <m.carrara at proxmox.com>
---

Notes:
    I ran into the second branch (the one for "Read-only file system")
    when testing things using my local NFS share—I figured I might as
    well handle that one too, since it's similar in nature.

 src/PVE/Storage/Plugin.pm | 25 +++++++++++++++++++++++--
 1 file changed, 23 insertions(+), 2 deletions(-)

diff --git a/src/PVE/Storage/Plugin.pm b/src/PVE/Storage/Plugin.pm
index 617b0f8..975641b 100644
--- a/src/PVE/Storage/Plugin.pm
+++ b/src/PVE/Storage/Plugin.pm
@@ -1903,6 +1903,28 @@ sub activate_storage {
         return;
     }
 
+    my $try_create_subdir = sub {
+        my ($vtype) = @_;
+
+        my $subdir = $class->get_subdir($scfg, $vtype);
+
+        eval { mkpath $subdir; };
+        if ($@) {
+            my $msg = "failed to create content directory '$subdir' for content '$vtype'";
+            my $msg_prompt = "ensure that the storage has read and write access!";
+
+            if ($@ =~ m/permission \s denied/ix) {
+                die "$msg - permission denied - $msg_prompt\n";
+            }
+
+            if ($@ =~ m/read -? only \s file \s? system/ix) {
+                die "$msg - read-only file system - $msg_prompt\n";
+            }
+
+            die "$msg - $@\n";
+        }
+    };
+
     # TODO: mkdir is basically deprecated since 8.0, but we don't warn here until 8.4 or 9.0, as we
     # only got the replacement in 8.0, so no real replacement window, and its really noisy.
 
@@ -1918,8 +1940,7 @@ sub activate_storage {
                 defined($scfg->{content}->{$vtype})
                 || ($vtype eq 'backup' && defined($scfg->{content}->{'rootdir'}))
             ) {
-                my $subdir = $class->get_subdir($scfg, $vtype);
-                mkpath $subdir;
+                $try_create_subdir->($vtype);
             }
         }
     }
-- 
2.47.3