[Libguestfs] [PATCH v2] New API: resize2fs_P

Maxim Perevedentsev mperevedentsev at virtuozzo.com
Wed Oct 14 15:13:29 UTC 2015


Added support for getting ext2/3/4 filesystem minimum size.
This is needed primarily for shrinking images.

Difference to v1: added test, style fixes.

---
 daemon/ext2.c        | 35 +++++++++++++++++++++++++++++++++++
 generator/actions.ml | 14 ++++++++++++++
 src/MAX_PROC_NR      |  2 +-
 3 files changed, 50 insertions(+), 1 deletion(-)

diff --git a/daemon/ext2.c b/daemon/ext2.c
index ebaf0f0..0cd6a66 100644
--- a/daemon/ext2.c
+++ b/daemon/ext2.c
@@ -279,6 +279,41 @@ do_resize2fs_M (const char *device)
   return 0;
 }

+int64_t
+do_resize2fs_P (const char *device)
+{
+  CLEANUP_FREE char *err = NULL, *out = NULL;
+  CLEANUP_FREE_STRING_LIST char **lines = NULL;
+  int r;
+  size_t i;
+  char *p;
+  int64_t ret;
+  const char *pattern = "Estimated minimum size of the filesystem: ";
+
+  r = command (&out, &err, str_resize2fs, "-P", device, NULL);
+  if (r == -1) {
+    reply_with_error ("%s", err);
+    return -1;
+  }
+
+  lines = split_lines (out);
+  if (lines == NULL)
+    return -1;
+
+  for (i = 0; lines[i] != NULL; ++i) {
+    if (verbose)
+      fprintf (stderr, "resize2fs_P: lines[%zu] = \"%s\"\n", i, lines[i]);
+
+    if ((p = strstr (lines[i], pattern))) {
+      if (sscanf (p + strlen(pattern), "%" SCNd64, &ret) != 1)
+        return -1;
+      return ret;
+    }
+  }
+
+  return -1;
+}
+
 /* Takes optional arguments, consult optargs_bitmask. */
 int
 do_e2fsck (const char *device,
diff --git a/generator/actions.ml b/generator/actions.ml
index a76b466..78de100 100644
--- a/generator/actions.ml
+++ b/generator/actions.ml
@@ -12751,6 +12751,20 @@ Only some filesystem types support setting UUIDs.

 To read the UUID on a filesystem, call C<guestfs_vfs_uuid>." };

+  { defaults with
+    name = "resize2fs_P"; added = (1, 31, 17);
+    style = RInt64 "sizeinblocks", [Device "device"], [];
+    proc_nr = Some 457;
+    tests = [
+      InitBasicFS, Always, TestRun (
+        [["resize2fs_P"; "/dev/sda1"]]), [];
+    ];
+    shortdesc = "get minimum filesystem size in blocks";
+    longdesc = "\
+Get the minimum filesystem size in blocks.
+
+See also L<resize2fs(8)>." };
+
 ]

 (* Non-API meta-commands available only in guestfish.
diff --git a/src/MAX_PROC_NR b/src/MAX_PROC_NR
index 8d38505..de2a00c 100644
--- a/src/MAX_PROC_NR
+++ b/src/MAX_PROC_NR
@@ -1 +1 @@
-456
+457
--
1.8.3.1




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