libmount: support loopdevs in mnt_table_is_fs_mounted()

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

1 files changed, 28 insertions, 2 deletions

diff --git a/libmount/src/tab.c b/libmount/src/tab.c
index 5b286538e..e5eb1063e 100644
--- 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;
 }