libmount: support loopdevs in mnt_table_is_fs_mounted()

Signed-off-by: Karel Zak <kzak@redhat.com>

diff --git a/libmount/src/tab.c b/libmount/src/tab.c
index 5b286538e2d3ac64f6ac8884ba8a1c8c422b50f4..e5eb1063eaa1ff48c42f394f02a19abc4d124ea0 100644 (file)
--- a/libmount/src/tab.c
+++ b/libmount/src/tab.c
@@ -45,6 +45,7 @@
 
 #include "mountP.h"
 #include "strutils.h"
+#include "loopdev.h"
 
 /**
  * mnt_new_table:
@@ -948,8 +949,31 @@ int mnt_table_is_fs_mounted(struct libmnt_table *tb, struct libmnt_fs *fstab_fs)
 
        while (mnt_table_next_fs(tb, &itr, &fs) == 0) {
 
-               if (!mnt_fs_streq_srcpath(fs, src))
-                       continue;
+               if (!mnt_fs_streq_srcpath(fs, src)) {
+                       /* The source does not match. Maybe the source is a loop
+                        * device backing file.
+                        */
+                       uint64_t offset = 0;
+                       char *val;
+                       size_t len;
+                       int flags;
+
+                       if (!mnt_fs_is_kernel(fs) ||
+                           !mnt_fs_get_srcpath(fs) ||
+                           !startswith(mnt_fs_get_srcpath(fs), "/dev/loop"))
+                               continue;       /* does not look like loopdev */
+
+                       if (mnt_fs_get_option(fstab_fs, "offset", &val, &len) == 0 &&
+                           mnt_parse_offset(val, len, &offset)) {
+                               DBG(FS, mnt_debug_h(fstab_fs, "failed to parse offset="));
+                               continue;
+                       } else
+                               flags = LOOPDEV_FL_OFFSET;
+
+                       if (loopdev_is_used(mnt_fs_get_srcpath(fs), src, offset, flags))
+                               break;
+               }
+
                if (root) {
                        const char *r = mnt_fs_get_root(fs);
                        if (!r || strcmp(r, root) != 0)
@@ -975,6 +999,8 @@ int mnt_table_is_fs_mounted(struct libmnt_table *tb, struct libmnt_fs *fstab_fs)
                rc = 1;         /* success */
 done:
        free(root);
+
+       DBG(TAB, mnt_debug_h(tb, "mnt_table_is_fs_mounted: %s [rc=%d]", src, rc));
        return rc;
 }