For punching holes via fallocate. This will be useful for the external
backup provider API to discard parts of the source. The 'file-handle'
mechanism there uses a fuse mount, which does not implement the
BLKDISCARD ioctl, but does implement fallocate.
Signed-off-by: Fiona Ebner <f.eb...@proxmox.com>
---
src/PVE/Storage/Common.pm | 30 ++++++++++++++++++++++++++++++
1 file changed, 30 insertions(+)
diff --git a/src/PVE/Storage/Common.pm b/src/PVE/Storage/Common.pm
index 3ae20dd..32ed26a 100644
--- a/src/PVE/Storage/Common.pm
+++ b/src/PVE/Storage/Common.pm
@@ -3,6 +3,13 @@ package PVE::Storage::Common;
use strict;
use warnings;
+use PVE::Syscall;
+
+use constant {
+ FALLOC_FL_KEEP_SIZE => 0x01, # see linux/falloc.h
+ FALLOC_FL_PUNCH_HOLE => 0x02, # see linux/falloc.h
+};
+
=pod
=head1 NAME
@@ -51,4 +58,27 @@ sub align_size_up : prototype($$) {
return $aligned_size;
}
+=pod
+
+=head3 deallocate
+
+ deallocate($file_handle, $offset, $length)
+
+Deallocates the range with C<$length> many bytes starting from offset
C<$offset>
+for the file associated to the file handle C<$file_handle>. Dies on failure.
+
+=cut
+
+sub deallocate : prototype($$$) {
+ my ($file_handle, $offset, $length) = @_;
+
+ my $mode = FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE;
+ $offset = int($offset);
+ $length = int($length);
+
+ if (syscall(PVE::Syscall::fallocate, fileno($file_handle), $mode, $offset,
$length) != 0) {
+ die "fallocate: punch hole failed (offset: $offset, length: $length) -
$!\n";
+ }
+}
+
1;
--
2.39.5
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