guestfs_mount adds -o sync implicitly. This causes a very large
performance problem for write-intensive programs (eg. virt-v2v).
Document this as a "gotcha".
Change the tests, guestfish, Sys::Guestfs::Lib, guestmount to use
mount-options instead.
(Note that this gotcha does not affect mount-ro).
The source of the performance problem was first identified by
Matthew Booth.
if (mp) {
mount_mps (mp->next);
if (mp) {
mount_mps (mp->next);
- if (!read_only)
- r = guestfs_mount (g, mp->device, mp->mountpoint);
- else
- r = guestfs_mount_ro (g, mp->device, mp->mountpoint);
+
+ /* Don't use guestfs_mount here because that will default to mount
+ * options -o sync,noatime. For more information, see guestfs(3)
+ * section "LIBGUESTFS GOTCHAS".
+ */
+ const char *options = read_only ? "ro" : "";
+ r = guestfs_mount_options (g, options, mp->device, mp->mountpoint);
if (r == -1)
exit (EXIT_FAILURE);
}
if (r == -1)
exit (EXIT_FAILURE);
}
if (mp) {
mount_mps (mp->next);
if (mp) {
mount_mps (mp->next);
- if (!read_only)
- r = guestfs_mount (g, mp->device, mp->mountpoint);
- else
- r = guestfs_mount_ro (g, mp->device, mp->mountpoint);
+
+ /* Don't use guestfs_mount here because that will default to mount
+ * options -o sync,noatime. For more information, see guestfs(3)
+ * section "LIBGUESTFS GOTCHAS".
+ */
+ const char *options = read_only ? "ro" : "";
+ r = guestfs_mount_options (g, options, mp->device, mp->mountpoint);
if (r == -1)
exit (EXIT_FAILURE);
}
if (r == -1)
exit (EXIT_FAILURE);
}
if($ro) {
$g->mount_ro ($mounts->{$_}, $_)
} else {
if($ro) {
$g->mount_ro ($mounts->{$_}, $_)
} else {
- $g->mount ($mounts->{$_}, $_)
+ $g->mount_options ("", $mounts->{$_}, $_)
ok (1);
$h->mkfs ("ext2", "/dev/sda1");
ok (1);
ok (1);
$h->mkfs ("ext2", "/dev/sda1");
ok (1);
-$h->mount ("/dev/sda1", "/");
+$h->mount_options ("", "/dev/sda1", "/");
ok (1);
$h->mkdir ("/p");
ok (1);
ok (1);
$h->mkdir ("/p");
ok (1);
launch
part-disk /dev/sda mbr
mkfs ext2 /dev/sda1
launch
part-disk /dev/sda mbr
mkfs ext2 /dev/sda1
+mount-options "" /dev/sda1 /
ll /../dev/console
ll /../dev/full
ll /../dev/mapper/
ll /../dev/console
ll /../dev/full
ll /../dev/mapper/
run
part-disk /dev/sda mbr
mkfs ext2 /dev/sda1
run
part-disk /dev/sda mbr
mkfs ext2 /dev/sda1
+mount-options "" /dev/sda1 /
mkdir /dev
-command /ignore-this-error
unmount-all
mkdir /dev
-command /ignore-this-error
unmount-all
part-disk /dev/sda mbr
mkfs ext2 /dev/sda1
part-disk /dev/sda mbr
mkfs ext2 /dev/sda1
+mount-options "" /dev/sda1 /
# Upload image, daemon should cancel because the image is too large
# to upload into itself.
# Upload image, daemon should cancel because the image is too large
# to upload into itself.
../fish/guestfish --remote run
../fish/guestfish --remote part-disk /dev/sda mbr
../fish/guestfish --remote mkfs ext2 /dev/sda1
../fish/guestfish --remote run
../fish/guestfish --remote part-disk /dev/sda mbr
../fish/guestfish --remote mkfs ext2 /dev/sda1
-../fish/guestfish --remote mount /dev/sda1 /
+../fish/guestfish --remote mount-options "" /dev/sda1 /
# Failure of the above commands will cause the guestfish listener to exit.
# Incorrect return from echo_daemon will not, so need to ensure the listener
# Failure of the above commands will cause the guestfish listener to exit.
# Incorrect return from echo_daemon will not, so need to ensure the listener
[InitEmpty, Always, TestOutput (
[["part_disk"; "/dev/sda"; "mbr"];
["mkfs"; "ext2"; "/dev/sda1"];
[InitEmpty, Always, TestOutput (
[["part_disk"; "/dev/sda"; "mbr"];
["mkfs"; "ext2"; "/dev/sda1"];
- ["mount"; "/dev/sda1"; "/"];
+ ["mount_options"; ""; "/dev/sda1"; "/"];
["write_file"; "/new"; "new file contents"; "0"];
["cat"; "/new"]], "new file contents")],
"make a filesystem",
["write_file"; "/new"; "new file contents"; "0"];
["cat"; "/new"]], "new file contents")],
"make a filesystem",
[InitEmpty, Always, TestOutputListOfDevices (
[["part_disk"; "/dev/sda"; "mbr"];
["mkfs"; "ext2"; "/dev/sda1"];
[InitEmpty, Always, TestOutputListOfDevices (
[["part_disk"; "/dev/sda"; "mbr"];
["mkfs"; "ext2"; "/dev/sda1"];
- ["mount"; "/dev/sda1"; "/"];
+ ["mount_options"; ""; "/dev/sda1"; "/"];
["mounts"]], ["/dev/sda1"]);
InitEmpty, Always, TestOutputList (
[["part_disk"; "/dev/sda"; "mbr"];
["mkfs"; "ext2"; "/dev/sda1"];
["mounts"]], ["/dev/sda1"]);
InitEmpty, Always, TestOutputList (
[["part_disk"; "/dev/sda"; "mbr"];
["mkfs"; "ext2"; "/dev/sda1"];
- ["mount"; "/dev/sda1"; "/"];
+ ["mount_options"; ""; "/dev/sda1"; "/"];
["umount"; "/"];
["mounts"]], [])],
"unmount a filesystem",
["umount"; "/"];
["mounts"]], [])],
"unmount a filesystem",
["mkfs"; "ext2"; "/dev/sda1"];
["mkfs"; "ext2"; "/dev/sda2"];
["mkfs"; "ext2"; "/dev/sda3"];
["mkfs"; "ext2"; "/dev/sda1"];
["mkfs"; "ext2"; "/dev/sda2"];
["mkfs"; "ext2"; "/dev/sda3"];
- ["mount"; "/dev/sda1"; "/"];
+ ["mount_options"; ""; "/dev/sda1"; "/"];
- ["mount"; "/dev/sda2"; "/mp1"];
+ ["mount_options"; ""; "/dev/sda2"; "/mp1"];
- ["mount"; "/dev/sda3"; "/mp1/mp2"];
+ ["mount_options"; ""; "/dev/sda3"; "/mp1/mp2"];
["mkdir"; "/mp1/mp2/mp3"];
["umount_all"];
["mounts"]], [])],
["mkdir"; "/mp1/mp2/mp3"];
["umount_all"];
["mounts"]], [])],
[InitNone, Always, TestOutput (
[["part_disk"; "/dev/sda"; "mbr"];
["mkfs"; "ext3"; "/dev/sda1"];
[InitNone, Always, TestOutput (
[["part_disk"; "/dev/sda"; "mbr"];
["mkfs"; "ext3"; "/dev/sda1"];
- ["mount"; "/dev/sda1"; "/"];
+ ["mount_options"; ""; "/dev/sda1"; "/"];
["write_file"; "/new"; "test file"; "0"];
["umount"; "/dev/sda1"];
["zerofree"; "/dev/sda1"];
["write_file"; "/new"; "test file"; "0"];
["umount"; "/dev/sda1"];
["zerofree"; "/dev/sda1"];
- ["mount"; "/dev/sda1"; "/"];
+ ["mount_options"; ""; "/dev/sda1"; "/"];
["cat"; "/new"]], "test file")],
"zero unused inodes and disk blocks on ext2/3 filesystem",
"\
["cat"; "/new"]], "test file")],
"zero unused inodes and disk blocks on ext2/3 filesystem",
"\
["vgcreate"; "VG"; "/dev/sda1"];
["lvcreate"; "LV"; "VG"; "10"];
["mkfs"; "ext2"; "/dev/VG/LV"];
["vgcreate"; "VG"; "/dev/sda1"];
["lvcreate"; "LV"; "VG"; "10"];
["mkfs"; "ext2"; "/dev/VG/LV"];
- ["mount"; "/dev/VG/LV"; "/"];
+ ["mount_options"; ""; "/dev/VG/LV"; "/"];
["write_file"; "/new"; "test content"; "0"];
["umount"; "/"];
["lvresize"; "/dev/VG/LV"; "20"];
["e2fsck_f"; "/dev/VG/LV"];
["resize2fs"; "/dev/VG/LV"];
["write_file"; "/new"; "test content"; "0"];
["umount"; "/"];
["lvresize"; "/dev/VG/LV"; "20"];
["e2fsck_f"; "/dev/VG/LV"];
["resize2fs"; "/dev/VG/LV"];
- ["mount"; "/dev/VG/LV"; "/"];
+ ["mount_options"; ""; "/dev/VG/LV"; "/"];
["cat"; "/new"]], "test content")],
"resize an LVM logical volume",
"\
["cat"; "/new"]], "test content")],
"resize an LVM logical volume",
"\
[InitEmpty, Always, TestOutput (
[["part_disk"; "/dev/sda"; "mbr"];
["mkfs_b"; "ext2"; "4096"; "/dev/sda1"];
[InitEmpty, Always, TestOutput (
[["part_disk"; "/dev/sda"; "mbr"];
["mkfs_b"; "ext2"; "4096"; "/dev/sda1"];
- ["mount"; "/dev/sda1"; "/"];
+ ["mount_options"; ""; "/dev/sda1"; "/"];
["write_file"; "/new"; "new file contents"; "0"];
["cat"; "/new"]], "new file contents")],
"make a filesystem with block size",
["write_file"; "/new"; "new file contents"; "0"];
["cat"; "/new"]], "new file contents")],
"make a filesystem with block size",
[["sfdiskM"; "/dev/sda"; ",100 ,"];
["mke2journal"; "4096"; "/dev/sda1"];
["mke2fs_J"; "ext2"; "4096"; "/dev/sda2"; "/dev/sda1"];
[["sfdiskM"; "/dev/sda"; ",100 ,"];
["mke2journal"; "4096"; "/dev/sda1"];
["mke2fs_J"; "ext2"; "4096"; "/dev/sda2"; "/dev/sda1"];
- ["mount"; "/dev/sda2"; "/"];
+ ["mount_options"; ""; "/dev/sda2"; "/"];
["write_file"; "/new"; "new file contents"; "0"];
["cat"; "/new"]], "new file contents")],
"make ext2/3/4 external journal",
["write_file"; "/new"; "new file contents"; "0"];
["cat"; "/new"]], "new file contents")],
"make ext2/3/4 external journal",
[["sfdiskM"; "/dev/sda"; ",100 ,"];
["mke2journal_L"; "4096"; "JOURNAL"; "/dev/sda1"];
["mke2fs_JL"; "ext2"; "4096"; "/dev/sda2"; "JOURNAL"];
[["sfdiskM"; "/dev/sda"; ",100 ,"];
["mke2journal_L"; "4096"; "JOURNAL"; "/dev/sda1"];
["mke2fs_JL"; "ext2"; "4096"; "/dev/sda2"; "JOURNAL"];
- ["mount"; "/dev/sda2"; "/"];
+ ["mount_options"; ""; "/dev/sda2"; "/"];
["write_file"; "/new"; "new file contents"; "0"];
["cat"; "/new"]], "new file contents")],
"make ext2/3/4 external journal with label",
["write_file"; "/new"; "new file contents"; "0"];
["cat"; "/new"]], "new file contents")],
"make ext2/3/4 external journal with label",
[["sfdiskM"; "/dev/sda"; ",100 ,"];
["mke2journal_U"; "4096"; uuid; "/dev/sda1"];
["mke2fs_JU"; "ext2"; "4096"; "/dev/sda2"; uuid];
[["sfdiskM"; "/dev/sda"; ",100 ,"];
["mke2journal_U"; "4096"; uuid; "/dev/sda1"];
["mke2fs_JU"; "ext2"; "4096"; "/dev/sda2"; uuid];
- ["mount"; "/dev/sda2"; "/"];
+ ["mount_options"; ""; "/dev/sda2"; "/"];
["write_file"; "/new"; "new file contents"; "0"];
["cat"; "/new"]], "new file contents")]),
"make ext2/3/4 external journal with UUID",
["write_file"; "/new"; "new file contents"; "0"];
["cat"; "/new"]], "new file contents")]),
"make ext2/3/4 external journal with UUID",
["vg_activate"; "false"; "VG"];
["vgrename"; "VG"; "VG2"];
["vg_activate"; "true"; "VG2"];
["vg_activate"; "false"; "VG"];
["vgrename"; "VG"; "VG2"];
["vg_activate"; "true"; "VG2"];
- ["mount"; "/dev/VG2/LV"; "/"];
+ ["mount_options"; ""; "/dev/VG2/LV"; "/"];
["vgs"]], ["VG2"])],
"rename an LVM volume group",
"\
["vgs"]], ["VG2"])],
"rename an LVM volume group",
"\
["lvm_remove_all"];
["part_disk"; "/dev/sda"; "mbr"];
["mkfs"; "ext2"; "/dev/sda1"];
["lvm_remove_all"];
["part_disk"; "/dev/sda"; "mbr"];
["mkfs"; "ext2"; "/dev/sda1"];
- ["mount"; "/dev/sda1"; "/"]]
+ ["mount_options"; ""; "/dev/sda1"; "/"]]
| InitBasicFSonLVM ->
pr " /* InitBasicFSonLVM for %s: create ext2 on /dev/VG/LV */\n"
test_name;
| InitBasicFSonLVM ->
pr " /* InitBasicFSonLVM for %s: create ext2 on /dev/VG/LV */\n"
test_name;
["vgcreate"; "VG"; "/dev/sda1"];
["lvcreate"; "LV"; "VG"; "8"];
["mkfs"; "ext2"; "/dev/VG/LV"];
["vgcreate"; "VG"; "/dev/sda1"];
["lvcreate"; "LV"; "VG"; "8"];
["mkfs"; "ext2"; "/dev/VG/LV"];
- ["mount"; "/dev/VG/LV"; "/"]]
+ ["mount_options"; ""; "/dev/VG/LV"; "/"]]
| InitISOFS ->
pr " /* InitISOFS for %s */\n" test_name;
List.iter (generate_test_command_call test_name)
| InitISOFS ->
pr " /* InitISOFS for %s */\n" test_name;
List.iter (generate_test_command_call test_name)
dirty guestfish scripts that forget to sync will work just fine, which
can make this extra-puzzling if you are trying to debug a problem.
dirty guestfish scripts that forget to sync will work just fine, which
can make this extra-puzzling if you are trying to debug a problem.
+=item Mount option C<-o sync> should not be the default.
+
+If you use C<guestfs_mount>, then C<-o sync,noatime> are added
+implicitly. However C<-o sync> does not add any reliability benefit,
+but does have a very large performance impact.
+
+The work around is to use C<guestfs_mount_options> and set the mount
+options that you actually want to use.
+
=item Read-only should be the default.
In L<guestfish(3)>, I<--ro> should be the default, and you should
=item Read-only should be the default.
In L<guestfish(3)>, I<--ro> should be the default, and you should
- if (guestfs_mount (g, "/dev/sda1", "/") == -1) {
+ if (guestfs_mount_options (g, "", "/dev/sda1", "/") == -1) {
fprintf (stderr,
_("libguestfs-test-tool: failed to mount /dev/sda1 on /\n"));
exit (EXIT_FAILURE);
fprintf (stderr,
_("libguestfs-test-tool: failed to mount /dev/sda1 on /\n"));
exit (EXIT_FAILURE);