Prevent ext[234] filesystems corruption

Some underlying device driver, e.g. the UML UBD driver, may manage holes incorrectly which will prevent to retrieve all usefull zero ranges in filesystem, e.g. when using 'bmaptool create' Assigning UNIX_IO_NOZEROOUT environment variable prevent mkfs.ext[234] utilities to create zero range spaces using fallocate with FALLOC_FL_ZERO_RANGE or FALLOC_FL_PUNCH_HOLE Signed-off-by: Frédéric Danis <[email protected]>
kgoger · Apr 19, 2022 · b324040 · b324040
1 parent aac4596
commit b324040
Showing 1 changed file with 13 additions and 0 deletions.
diff --git a/actions/image_partition_action.go b/actions/image_partition_action.go
@@ -350,6 +350,19 @@ func (i ImagePartitionAction) formatPartition(p *Partition, context debos.DebosC
 		cmdline = append(cmdline, path)
 
 		cmd := debos.Command{}
+
+		/* Some underlying device driver, e.g. the UML UBD driver, may manage holes
+		 * incorrectly which will prevent to retrieve all usefull zero ranges in
+		 * filesystem, e.g. when using 'bmaptool create', see patch
+		 * http://lists.infradead.org/pipermail/linux-um/2022-January/002074.html
+		 *
+		 * Adding UNIX_IO_NOZEROOUT environment variable prevent mkfs.ext[234]
+		 * utilities to create zero range spaces using fallocate with
+		 * FALLOC_FL_ZERO_RANGE or FALLOC_FL_PUNCH_HOLE */
+		if p.FS == "ext2" || p.FS == "ext3" || p.FS == "ext4" {
+			cmd.AddEnv("UNIX_IO_NOZEROOUT=1")
+		}
+
 		if err := cmd.Run(label, cmdline...); err != nil {
 			return err
 		}