New API: btrfs_balance_status

Signed-off-by: Hu Tao <hutao@cn.fujitsu.com>
Signed-off-by: Chen Hanxiao <chenhanxiao@cn.fujitsu.com>

daemon/btrfs.c

@@ -1659,3 +1659,129 @@ do_btrfs_rescue_super_recover (const char *device)
 
   return 0;
 }
+
+guestfs_int_btrfsbalance *
+do_btrfs_balance_status (const char *path)
+{
+  const size_t MAX_ARGS = 64;
+  const char *argv[MAX_ARGS];
+  size_t i = 0;
+  CLEANUP_FREE char *path_buf = NULL;
+  CLEANUP_FREE char *err = NULL;
+  char *out;
+  int r;
+  guestfs_int_btrfsbalance *ret;
+  char **lines;
+  size_t nlines;
+  const char *errptr;
+  int erroffset;
+#define N_MATCH 2
+  int ovector[N_MATCH * 3];
+  pcre *re = NULL;
+
+  path_buf = sysroot_path (path);
+  if (path_buf == NULL) {
+    reply_with_perror ("malloc");
+    return NULL;
+  }
+
+  ADD_ARG (argv, i, str_btrfs);
+  ADD_ARG (argv, i, "balance");
+  ADD_ARG (argv, i, "status");
+  ADD_ARG (argv, i, path_buf);
+  ADD_ARG (argv, i, NULL);
+
+  r = commandv (&out, &err, argv);
+  if (r == -1) {
+    reply_with_error ("%s: %s", path, err);
+    return NULL;
+  }
+
+  lines = split_lines (out);
+  if (!lines)
+    return NULL;
+
+  nlines = count_strings (lines);
+
+  ret = malloc(sizeof *ret);
+  if (ret == NULL) {
+    reply_with_perror ("malloc");
+    goto error;
+  }
+  memset (ret, 0, sizeof(*ret));
+
+  /* Output of `btrfs balance status' is like:
+   *
+   * running:
+   *
+   *   Balance on '/' is running
+   *   3 out of about 8 chunks balanced (3 considered), 62% left
+   *
+   * paused:
+   *
+   *   Balance on '/' is paused
+   *   3 out of about 8 chunks balanced (3 considered), 62% left
+   *
+   * no balance running:
+   *
+   *   No Balance found on '/'
+   *
+   */
+  if (nlines < 1) {
+    reply_with_perror ("No balance status output");
+    return NULL;
+  }
+
+  if (strstr (lines[0], "No balance found on")) {
+    ret->btrfsbalance_status = strdup("none");
+    if (ret->btrfsbalance_status == NULL) {
+      reply_with_perror ("strdup");
+      return NULL;
+    }
+    return ret;
+  }
+
+  re = pcre_compile ("Balance on '.*' is (.*)", 0, &errptr, &erroffset, NULL);
+  if (re == NULL) {
+    reply_with_error ("pcre_compile (%i): %s", erroffset, errptr);
+    goto error;
+  }
+  if (pcre_exec (re, NULL, lines[0], strlen (lines[0]), 0, 0,
+                 ovector, N_MATCH * 3) < 0) {
+    reply_with_error ("unexpected output from 'btrfs balance status' command: %s", lines[0]);
+    goto error;
+  }
+#undef N_MATCH
+
+  if (STREQ (lines[0] + ovector[2], "running"))
+    ret->btrfsbalance_status = strdup("running");
+  else if (STREQ (lines[0] + ovector[2], "paused"))
+    ret->btrfsbalance_status = strdup("paused");
+  else {
+    reply_with_error ("unexpected output from 'btrfs balance status' command: %s", lines[0]);
+    goto error;
+  }
+
+  if (nlines < 2) {
+    reply_with_error ("truncated output from 'btrfs balance status' command");
+    goto error;
+  }
+
+  if (sscanf (lines[1], "%" SCNu64 " out of about %" SCNu64
+              " chunks balanced (%" SCNu64 " considered), %" SCNu64 "%% left",
+              &ret->btrfsbalance_balanced, &ret->btrfsbalance_total,
+              &ret->btrfsbalance_considered, &ret->btrfsbalance_left) != 4) {
+    reply_with_perror ("sscanf");
+    goto error;
+  }
+
+  pcre_free (re);
+  return ret;
+
+error:
+  free (ret->btrfsbalance_status);
+  free (ret);
+  pcre_free (re);
+
+  return NULL;
+}

generator/actions.ml

@@ -12449,6 +12449,16 @@ valid GUID." };
     longdesc = "\
 Return the GUID of numbered GPT partition C<partnum>." };
 
+{ defaults with
+    name = "btrfs_balance_status";
+    style = RStruct ("status", "btrfsbalance"), [Pathname "path"], [];
+    proc_nr = Some 448;
+    optional = Some "btrfs"; camel_name = "BTRFSBalanceStatus";
+    test_excuse = "test disk isn't large enough that btrfs_balance completes before we can get its status";
+    shortdesc = "show the status of a running or paused balance";
+    longdesc = "\
+Show the status of a running or paused balance on a btrfs filesystem." };
+
 ]
 
 (* Non-API meta-commands available only in guestfish.

generator/structs.ml

@@ -340,6 +340,18 @@ let structs = [
     ];
     s_camel_name = "BTRFSQgroup" };
 
+  (* btrfs balance status output *)
+  { defaults with
+    s_name = "btrfsbalance";
+    s_cols = [
+      "btrfsbalance_status", FString;
+      "btrfsbalance_total", FUInt64;
+      "btrfsbalance_balanced", FUInt64;
+      "btrfsbalance_considered", FUInt64;
+      "btrfsbalance_left", FUInt64;
+    ];
+    s_camel_name = "BTRFSBalance" };
+
   (* XFS info descriptor. *)
   { defaults with
     s_name = "xfsinfo";

gobject/Makefile.inc

@@ -25,6 +25,7 @@ guestfs_gobject_headers= \
   include/guestfs-gobject/tristate.h \
   include/guestfs-gobject/struct-application.h \
   include/guestfs-gobject/struct-application2.h \
+  include/guestfs-gobject/struct-btrfsbalance.h \
   include/guestfs-gobject/struct-btrfsqgroup.h \
   include/guestfs-gobject/struct-btrfssubvolume.h \
   include/guestfs-gobject/struct-dirent.h \
@@ -108,6 +109,7 @@ guestfs_gobject_sources= \
   src/tristate.c \
   src/struct-application.c \
   src/struct-application2.c \
+  src/struct-btrfsbalance.c \
   src/struct-btrfsqgroup.c \
   src/struct-btrfssubvolume.c \
   src/struct-dirent.c \

java/Makefile.inc

@@ -22,6 +22,7 @@
 java_built_sources = \
 	com/redhat/et/libguestfs/Application.java \
 	com/redhat/et/libguestfs/Application2.java \
+	com/redhat/et/libguestfs/BTRFSBalance.java \
 	com/redhat/et/libguestfs/BTRFSQgroup.java \
 	com/redhat/et/libguestfs/BTRFSSubvolume.java \
 	com/redhat/et/libguestfs/Dirent.java \

java/com/redhat/et/libguestfs/.gitignore

@@ -1,5 +1,6 @@
 Application.java
 Application2.java
+BTRFSBalance.java
 BTRFSQgroup.java
 BTRFSSubvolume.java
 Dirent.java

po/POTFILES

@@ -230,6 +230,7 @@ gobject/src/optargs-xfs_repair.c
 gobject/src/session.c
 gobject/src/struct-application.c
 gobject/src/struct-application2.c
+gobject/src/struct-btrfsbalance.c
 gobject/src/struct-btrfsqgroup.c
 gobject/src/struct-btrfssubvolume.c
 gobject/src/struct-dirent.c

src/MAX_PROC_NR

@@ -1 +1 @@
-447
+448