libmount: support {offset,sizelimit}= foor loopdevs

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

diff --git a/libmount/src/context_loopdev.c b/libmount/src/context_loopdev.c
index 992472e3d867d24d4ce22ef55b1a9c0c1aa5756e..084f08fa44ec2f689c25cd6b82caf3a724780cd1 100644 (file)
--- a/libmount/src/context_loopdev.c
+++ b/libmount/src/context_loopdev.c
@@ -65,11 +65,12 @@ int mnt_context_is_loopdev(struct libmnt_context *cxt)
 
 int mnt_context_setup_loopdev(struct libmnt_context *cxt)
 {
-       const char *backing_file;
-       char *loopdev = NULL;
+       const char *backing_file, *optstr;
+       char *loopdev = NULL, *val = NULL;
        size_t len;
        struct loopdev_cxt lc;
-       int rc, lo_flags = 0;
+       int rc = 0, lo_flags = 0;
+       uint64_t offset = 0, sizelimit = 0;
 
        assert(cxt);
        assert(cxt->fs);
@@ -87,19 +88,42 @@ int mnt_context_setup_loopdev(struct libmnt_context *cxt)
        }
        loopcxt_init(&lc, 0);
 
-       
-       if ((cxt->user_mountflags & MNT_MS_LOOP) &&
-           mnt_fs_get_option(cxt->fs, "loop", &loopdev, &len) == 0 && loopdev) {
+       optstr = mnt_fs_get_user_options(cxt->fs);
 
-               char *tmp = strndup(loopdev, len);
-               if (!tmp)
-                       rc = -ENOMEM;
-               else {
-                       rc = loopcxt_set_device(&lc, tmp);
-                       free(tmp);
-               }
+       /*
+        * loop=
+        */
+       if (rc == 0 && (cxt->user_mountflags & MNT_MS_LOOP) &&
+           mnt_optstr_get_option(optstr, "loop", &val, &len) == 0 && val) {
+
+               val = strndup(val, len);
+               rc = val ? loopcxt_set_device(&lc, val) : -ENOMEM;
+               free(val);
+       }
+
+       /*
+        * offset=
+        */
+       if (rc == 0 && (cxt->user_mountflags & MNT_MS_OFFSET) &&
+           mnt_optstr_get_option(optstr, "offset", &val, &len) == 0) {
+               rc = mnt_parse_offset(val, len, &offset);
+               if (rc)
+                       DBG(CXT, mnt_debug_h(cxt, "failed to parse offset="));
        }
 
+       /*
+        * sizelimit=
+        */
+       if (rc == 0 && (cxt->user_mountflags & MNT_MS_SIZELIMIT) &&
+           mnt_optstr_get_option(optstr, "sizelimit", &val, &len) == 0) {
+               rc = mnt_parse_offset(val, len, &sizelimit);
+               if (rc)
+                       DBG(CXT, mnt_debug_h(cxt, "failed to parse sizelimit="));
+       }
+
+       if (rc)
+               goto done;
+
        /* since 2.6.37 we don't have to store backing filename to mtab
         * because kernel provides the name in /sys.
         */
@@ -119,12 +143,21 @@ int mnt_context_setup_loopdev(struct libmnt_context *cxt)
                                                loopcxt_get_device(&lc)));
                }
 
-               /* set device attributes */
+               /* set device attributes
+                * -- note that loopcxt_find_unused() resets "lc"
+                */
                rc = loopcxt_set_backing_file(&lc, backing_file);
-               if (rc)
-                       goto done;
 
-               loopcxt_set_flags(&lc, lo_flags);
+               if (!rc && offset)
+                       rc = loopcxt_set_offset(&lc, offset);
+               if (!rc && sizelimit)
+                       rc = loopcxt_set_sizelimit(&lc, sizelimit);
+               if (!rc)
+                       loopcxt_set_flags(&lc, lo_flags);
+               if (rc) {
+                       DBG(CXT, mnt_debug_h(cxt, "failed to set loopdev attributes"));
+                       goto done;
+               }
 
                /* setup the device */
                rc = loopcxt_setup_device(&lc);
@@ -133,7 +166,7 @@ int mnt_context_setup_loopdev(struct libmnt_context *cxt)
 
                if (loopdev || rc != -EBUSY) {
                        DBG(CXT, mnt_debug_h(cxt, "failed to setup device"));
-                       break;
+                       goto done;
                }
                DBG(CXT, mnt_debug_h(cxt, "loopdev stolen...trying again"));
        } while (1);