From 945cc03b42ec947876cda10dff1bf76a446abbf1 Mon Sep 17 00:00:00 2001
Message-Id: <945cc03b42ec947876cda10dff1bf76a446abbf1@dist-git>
From: Michal Privoznik <mprivozn@redhat.com>
Date: Wed, 3 Oct 2018 17:04:13 +0200
Subject: [PATCH] virFileIsSharedFSType: Check for fuse.glusterfs too

RHEL-7.7: https://bugzilla.redhat.com/show_bug.cgi?id=1632711
RHEL-8.0: https://bugzilla.redhat.com/show_bug.cgi?id=1634782
RHEL-7.6.z: https://bugzilla.redhat.com/show_bug.cgi?id=1635705

GlusterFS is typically safe when it comes to migration. It's a
network FS after all. However, it can be mounted via FUSE driver
they provide. If that is the case we fail to identify it and
think migration is not safe and require VIR_MIGRATE_UNSAFE flag.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Jiri Denemark <jdenemar@redhat.com>
(cherry picked from commit 478da65fb46c866973886848ae17f1e16199a77d)
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
---
 src/util/virfile.c | 77 ++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 75 insertions(+), 2 deletions(-)

diff --git a/src/util/virfile.c b/src/util/virfile.c
index 378d03ecf0..c87e26bf5b 100644
--- a/src/util/virfile.c
+++ b/src/util/virfile.c
@@ -3534,6 +3534,76 @@ int virFilePrintf(FILE *fp, const char *msg, ...)
 # ifndef HUGETLBFS_MAGIC
 #  define HUGETLBFS_MAGIC 0x958458f6
 # endif
+# ifndef FUSE_SUPER_MAGIC
+#  define FUSE_SUPER_MAGIC 0x65735546
+# endif
+
+# define PROC_MOUNTS "/proc/mounts"
+
+static int
+virFileIsSharedFixFUSE(const char *path,
+                       long *f_type)
+{
+    char *dirpath = NULL;
+    const char **mounts = NULL;
+    size_t nmounts = 0;
+    char *p;
+    FILE *f = NULL;
+    struct mntent mb;
+    char mntbuf[1024];
+    int ret = -1;
+
+    if (VIR_STRDUP(dirpath, path) < 0)
+        return -1;
+
+    if (!(f = setmntent(PROC_MOUNTS, "r"))) {
+        virReportSystemError(errno,
+                             _("Unable to open %s"),
+                             PROC_MOUNTS);
+        goto cleanup;
+    }
+
+    while (getmntent_r(f, &mb, mntbuf, sizeof(mntbuf))) {
+        if (STRNEQ("fuse.glusterfs", mb.mnt_type))
+            continue;
+
+        if (VIR_APPEND_ELEMENT_COPY(mounts, nmounts, mb.mnt_dir) < 0)
+            goto cleanup;
+    }
+
+    /* Add NULL sentinel so that this is a virStringList */
+    if (VIR_REALLOC_N(mounts, nmounts + 1) < 0)
+        goto cleanup;
+    mounts[nmounts] = NULL;
+
+    do {
+        if ((p = strrchr(dirpath, '/')) == NULL) {
+            virReportSystemError(EINVAL,
+                                 _("Invalid relative path '%s'"), path);
+            goto cleanup;
+        }
+
+        if (p == dirpath)
+            *(p+1) = '\0';
+        else
+            *p = '\0';
+
+        if (virStringListHasString(mounts, dirpath)) {
+            VIR_DEBUG("Found gluster FUSE mountpoint=%s for path=%s. "
+                      "Fixing shared FS type", dirpath, path);
+            *f_type = GFS2_MAGIC;
+            break;
+        }
+    } while (p != dirpath);
+
+    ret = 0;
+ cleanup:
+    endmntent(f);
+    VIR_FREE(mounts);
+    VIR_FREE(dirpath);
+    return ret;
+}
+
 
 int
 virFileIsSharedFSType(const char *path,
@@ -3581,6 +3651,11 @@ virFileIsSharedFSType(const char *path,
         return -1;
     }
 
+    if (sb.f_type == FUSE_SUPER_MAGIC) {
+        VIR_DEBUG("Found FUSE mount for path=%s. Trying to fix it", path);
+        virFileIsSharedFixFUSE(path, (long *) &sb.f_type);
+    }
+
     VIR_DEBUG("Check if path %s with FS magic %lld is shared",
               path, (long long int)sb.f_type);
 
@@ -3673,8 +3748,6 @@ virFileGetDefaultHugepageSize(unsigned long long *size)
     return ret;
 }
 
-# define PROC_MOUNTS "/proc/mounts"
-
 int
 virFileFindHugeTLBFS(virHugeTLBFSPtr *ret_fs,
                      size_t *ret_nfs)
-- 
2.21.0