[Libguestfs] [PATCH 1/2] New API: lvm-canonical-lv-name: make LV name canonical.
Richard W.M. Jones
rjones at redhat.com
Mon Oct 25 12:04:49 UTC 2010
--
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
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>From 6ea93c0fd208a60d14306e76f2ca7ebc2a73f49f Mon Sep 17 00:00:00 2001
From: Richard W.M. Jones <rjones at redhat.com>
Date: Mon, 25 Oct 2010 12:52:49 +0100
Subject: [PATCH 1/2] New API: lvm-canonical-lv-name: make LV name canonical.
When logical volume names appear in places like /etc/fstab
files they can have the form "/dev/mapper/foo-bar". This
function takes such names and makes them canonical.
Note that this operation cannot be performed using the current
API, because 'guestfs_stat' does not work on device names, and
we don't really want to make a 'stat-device' call since that
exposes too much non-useful detail about the appliance.
With this patch you can do this:
><fs> debug ll /dev/mapper
total 8
drwxrwxr-x 2 root root 4096 Oct 25 12:51 .
drwxr-xr-x 16 root root 4096 Oct 25 12:51 ..
crw------- 1 root root 10, 62 Oct 25 12:51 control
lrwxrwxrwx 1 root root 7 Oct 25 12:51 vg_f13x64-lv_root -> ../dm-0
lrwxrwxrwx 1 root root 7 Oct 25 12:51 vg_f13x64-lv_swap -> ../dm-1
><fs> lvm-canonical-lv-name /dev/mapper/vg_f13x64-lv_root
/dev/vg_f13x64/lv_root
><fs> lvm-canonical-lv-name /dev/mapper/vg_f13x64-lv_swap
/dev/vg_f13x64/lv_swap
><fs> lvm-canonical-lv-name /dev/mapper/foo
libguestfs: error: lvm_canonical_lv_name: lvm_canonical_lv_name_stub: /dev/mapper/foo: No such file or directory
><fs> lvm-canonical-lv-name /dev/mapper/control
libguestfs: error: lvm_canonical_lv_name: /dev/mapper/control: not a logical volume
><fs> lvm-canonical-lv-name /dev/vg_f13x64/lv_root
/dev/vg_f13x64/lv_root
---
daemon/lvm.c | 42 ++++++++++++++++++++++++++++++++++++++++
generator/generator_actions.ml | 16 +++++++++++++++
src/MAX_PROC_NR | 2 +-
3 files changed, 59 insertions(+), 1 deletions(-)
diff --git a/daemon/lvm.c b/daemon/lvm.c
index 0df27e2..2691daa 100644
--- a/daemon/lvm.c
+++ b/daemon/lvm.c
@@ -709,3 +709,45 @@ do_is_lv (const char *device)
free_strings (lvs);
return 0;
}
+
+/* Similar to is_lv above (RHBZ#638899). */
+char *
+do_lvm_canonical_lv_name (const char *device)
+{
+ struct stat stat1, stat2;
+
+ int r = stat (device, &stat1);
+ if (r == -1) {
+ reply_with_perror ("stat: %s", device);
+ return NULL;
+ }
+
+ char **lvs = do_lvs ();
+ if (lvs == NULL)
+ return NULL;
+
+ size_t i;
+ for (i = 0; lvs[i] != NULL; ++i) {
+ r = stat (lvs[i], &stat2);
+ if (r == -1) {
+ reply_with_perror ("stat: %s", lvs[i]);
+ free_strings (lvs);
+ return NULL;
+ }
+ if (stat1.st_rdev == stat2.st_rdev) { /* found it */
+ char *r = strdup (lvs[i]);
+ if (r == NULL) {
+ reply_with_perror ("strdup");
+ free_strings (lvs);
+ }
+ free_strings (lvs);
+ return r;
+ }
+ }
+
+ free_strings (lvs);
+
+ /* not found */
+ reply_with_error ("%s: not a logical volume", device);
+ return NULL;
+}
diff --git a/generator/generator_actions.ml b/generator/generator_actions.ml
index 695a73d..38f1db3 100644
--- a/generator/generator_actions.ml
+++ b/generator/generator_actions.ml
@@ -5208,6 +5208,22 @@ see the L<pread(2)> system call.
See also C<guestfs_pread>.");
+ ("lvm_canonical_lv_name", (RString "lv", [Device "lvname"], []), 277, [],
+ [InitBasicFSonLVM, IfAvailable "lvm2", TestOutput (
+ [["lvm_canonical_lv_name"; "/dev/mapper/VG-LV"]], "/dev/VG/LV");
+ InitBasicFSonLVM, IfAvailable "lvm2", TestOutput (
+ [["lvm_canonical_lv_name"; "/dev/VG/LV"]], "/dev/VG/LV")],
+ "get canonical name of an LV",
+ "\
+This converts alternative naming schemes for LVs that you
+might find to the canonical name. For example, C</dev/mapper/VG-LV>
+is converted to C</dev/VG/LV>.
+
+This command returns an error if the C<lvname> parameter does
+not refer to a logical volume.
+
+See also C<guestfs_is_lv>.");
+
]
let all_functions = non_daemon_functions @ daemon_functions
diff --git a/src/MAX_PROC_NR b/src/MAX_PROC_NR
index 15007f1..2681747 100644
--- a/src/MAX_PROC_NR
+++ b/src/MAX_PROC_NR
@@ -1 +1 @@
-276
+277
--
1.7.3.1
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