New API: Replace btrfs-fsck with btrfs-scrub-full

The old btrfs-fsck API used "btrfs check" which appears to be broken
or deprecated.  The real tool you should use is "btrfs scrub".  We
have already implemented that API, but it is very awkward to use from
libguestfs.  In particular there's no existing way to run the scrub
and wait for it to finish.

Fix this by deprecating btrfs-fsck.  Implement a new API
btrfs-scrub-full which runs btrfs scrub in the foreground, waits for
it to finish, and handles errors.  It's much more like fsck tools in
other filesystems.

Thanks: Eric Sandeen
Fixes: https://issues.redhat.com/browse/RHEL-91936

daemon/btrfs.c

@@ -1450,6 +1450,47 @@ do_btrfs_scrub_resume (const char *path)
   return 0;
 }
 
+/* Takes optional arguments, consult optargs_bitmask. */
+int
+do_btrfs_scrub_full (const char *path, int readonly)
+{
+  const size_t MAX_ARGS = 64;
+  const char *argv[MAX_ARGS];
+  size_t i = 0;
+  CLEANUP_FREE char *path_buf = NULL;
+  CLEANUP_FREE char *out = NULL, *err = NULL;
+  int r;
+
+  path_buf = sysroot_path (path);
+  if (path_buf == NULL) {
+    reply_with_perror ("malloc");
+    return -1;
+  }
+
+  ADD_ARG (argv, i, "btrfs");
+  ADD_ARG (argv, i, "scrub");
+  ADD_ARG (argv, i, "start");
+  ADD_ARG (argv, i, "-B");      /* foreground */
+
+  /* Optional arguments. */
+  if ((optargs_bitmask & GUESTFS_BTRFS_SCRUB_FULL_READONLY_BITMASK) &&
+      readonly)
+    ADD_ARG (argv, i, "-r");
+
+  ADD_ARG (argv, i, path_buf);
+  ADD_ARG (argv, i, NULL);
+
+  r = commandvf (&out, &err,
+                 COMMAND_FLAG_FOLD_STDOUT_ON_STDERR,
+                 argv);
+  if (r == -1) {
+    reply_with_error ("%s: %s", path, err);
+    return -1;
+  }
+
+  return 0;
+}
+
 int
 do_btrfs_balance_pause (const char *path)
 {

docs/guestfs-release-notes-1.56.pod

@@ -26,6 +26,9 @@ New C<command_out> and C<sh_out> APIs which allow you to capture
 output from guest commands that generate more output than the protocol
 limit allows.
 
+New C<btrfs_scrub_full> API which runs a full Btrfs scrub,
+synchronously.  It works more like fsck for other filesystems.
+
 The C<fstrim> API has been modified to work around several issues in
 upstream and RHEL 9 kernels related to XFS support (Eric Sandeen, Dave
 Chinner).

generator/actions_core.ml

@@ -7344,20 +7344,6 @@ If C<devices> is an empty list, this does nothing." };
 Enable or disable the seeding feature of a device that contains
 a btrfs filesystem." };
 
-  { defaults with
-    name = "btrfs_fsck"; added = (1, 17, 43);
-    style = RErr, [String (Device, "device")], [OInt64 "superblock"; OBool "repair"];
-    optional = Some "btrfs";
-    tests = [
-      InitPartition, Always, TestRun (
-        [["mkfs_btrfs"; "/dev/sda1"; ""; ""; "NOARG"; ""; "NOARG"; "NOARG"; ""; ""];
-         ["btrfs_fsck"; "/dev/sda1"; ""; ""]]), []
-    ];
-    shortdesc = "check a btrfs filesystem";
-    longdesc = "\
-Used to check a btrfs filesystem, C<device> is the device file where the
-filesystem is stored." };
-
   { defaults with
     name = "filesystem_available"; added = (1, 19, 5);
     style = RBool "fsavail", [String (PlainString, "filesystem")], [];
@@ -9082,6 +9068,21 @@ Show the status of a running or paused balance on a btrfs filesystem." };
     longdesc = "\
 Show status of running or finished scrub on a btrfs filesystem." };
 
+  { defaults with
+    name = "btrfs_scrub_full"; added = (1, 55, 12);
+    style = RErr, [String (Pathname, "path")], [OBool "readonly"];
+    optional = Some "btrfs"; camel_name = "BTRFSScrubFull";
+    tests = [
+      InitPartition, Always, TestRun (
+        [["mkfs_btrfs"; "/dev/sda1"; ""; ""; "NOARG"; ""; "NOARG"; "NOARG"; ""; ""];
+         ["mount"; "/dev/sda1"; "/"];
+         ["btrfs_scrub_full"; "/"; "false"]]), [];
+    ];
+    shortdesc = "run a full scrub on a btrfs filesystem";
+    longdesc = "\
+Run a full scrub on a btrfs filesystem and wait for it to finish.
+If the filesystem has errors this will return an error." };
+
   { defaults with
     name = "btrfstune_seeding"; added = (1, 29, 29);
     style = RErr, [String (Device, "device"); Bool "seeding"], [];

generator/actions_core_deprecated.ml

@@ -927,4 +927,19 @@ This call does nothing and returns an error." };
     longdesc = "\
 This call does nothing and returns an error." };
 
+  { defaults with
+    name = "btrfs_fsck"; added = (1, 17, 43);
+    style = RErr, [String (Device, "device")], [OInt64 "superblock"; OBool "repair"];
+    optional = Some "btrfs";
+    deprecated_by = Replaced_by "btrfs_scrub_full";
+    tests = [
+      InitPartition, Always, TestRun (
+        [["mkfs_btrfs"; "/dev/sda1"; ""; ""; "NOARG"; ""; "NOARG"; "NOARG"; ""; ""];
+         ["btrfs_fsck"; "/dev/sda1"; ""; ""]]), []
+    ];
+    shortdesc = "check a btrfs filesystem";
+    longdesc = "\
+Used to check a btrfs filesystem, C<device> is the device file where the
+filesystem is stored." };
+
 ]

generator/proc_nr.ml

@@ -520,6 +520,7 @@ let proc_nr = [
 515, "findfs_partlabel";
 516, "command_out";
 517, "sh_out";
+518, "btrfs_scrub_full";
 ]
 
 (* End of list.  If adding a new entry, add it at the end of the list

gobject/Makefile.inc

@@ -59,6 +59,7 @@ guestfs_gobject_headers= \
   include/guestfs-gobject/optargs-btrfs_filesystem_resize.h \
   include/guestfs-gobject/optargs-btrfs_fsck.h \
   include/guestfs-gobject/optargs-btrfs_image.h \
+  include/guestfs-gobject/optargs-btrfs_scrub_full.h \
   include/guestfs-gobject/optargs-btrfs_subvolume_create.h \
   include/guestfs-gobject/optargs-btrfs_subvolume_snapshot.h \
   include/guestfs-gobject/optargs-compress_device_out.h \
@@ -153,6 +154,7 @@ guestfs_gobject_sources= \
   src/optargs-btrfs_filesystem_resize.c \
   src/optargs-btrfs_fsck.c \
   src/optargs-btrfs_image.c \
+  src/optargs-btrfs_scrub_full.c \
   src/optargs-btrfs_subvolume_create.c \
   src/optargs-btrfs_subvolume_snapshot.c \
   src/optargs-compress_device_out.c \

lib/MAX_PROC_NR

@@ -1 +1 @@
-517
+518