libmount: fix superblock rw/ro reconfiguration

The classic mount(2) defaults to 'rw', but the new API does not reset
superblock to 'rw' if the flag is not explicitly used for
FSCONFIG_CMD_RECONFIGURE.

Addresses: https://bugzilla.redhat.com/show_bug.cgi?id=2180593
Signed-off-by: Karel Zak <kzak@redhat.com>

diff --git a/libmount/src/hook_mount.c b/libmount/src/hook_mount.c
index 071dad783dde8bbd881bea6daa3d883960b8552c..117150dec284c525be2aafe2d43f2627114f4247 100644 (file)
--- a/libmount/src/hook_mount.c
+++ b/libmount/src/hook_mount.c
@@ -111,14 +111,33 @@ static int hookset_deinit(struct libmnt_context *cxt, const struct libmnt_hookse
        return 0;
 }
 
+static inline int fsconfig_set_value(
+                       struct libmnt_context *cxt,
+                       const struct libmnt_hookset *hs,
+                       int fd,
+                       const char *name, const char *value)
+{
+       int rc;
+
+       DBG(HOOK, ul_debugobj(hs, "  fsconfig(name=%s,value=%s)", name,
+                               value ? : ""));
+       if (value)
+               rc = fsconfig(fd, FSCONFIG_SET_STRING, name, value, 0);
+       else
+               rc = fsconfig(fd, FSCONFIG_SET_FLAG, name, NULL, 0);
+
+       set_syscall_status(cxt, "fsconfig", rc == 0);
+       return rc;
+}
 
 static int configure_superblock(struct libmnt_context *cxt,
-                               const struct libmnt_hookset *hs, int fd)
+                               const struct libmnt_hookset *hs,
+                               int fd, int force_rwro)
 {
        struct libmnt_optlist *ol;
        struct libmnt_iter itr;
        struct libmnt_opt *opt;
-       int rc;
+       int rc = 0, has_rwro = 0;
 
        DBG(HOOK, ul_debugobj(hs, " config FS"));
 
@@ -136,22 +155,21 @@ static int configure_superblock(struct libmnt_context *cxt,
                if (ent && mnt_opt_get_map(opt) == cxt->map_linux &&
                    ent->id == MS_RDONLY) {
                        value = NULL;
+                       has_rwro = 1;
                } else if (!name || mnt_opt_get_map(opt) || mnt_opt_is_external(opt))
                        continue;
 
-               DBG(HOOK, ul_debugobj(hs, "  fsconfig(name=%s,value=%s)", name, value));
-               if (value)
-                       rc = fsconfig(fd, FSCONFIG_SET_STRING, name, value, 0);
-               else
-                       rc = fsconfig(fd, FSCONFIG_SET_FLAG, name, NULL, 0);
-
-               set_syscall_status(cxt, "fsconfig", rc == 0);
+               rc = fsconfig_set_value(cxt, hs, fd, name, value);
                if (rc != 0)
-                       return -errno;
+                       goto done;
        }
 
-       DBG(HOOK, ul_debugobj(hs, " config done [rc=0]"));
-       return 0;
+       if (force_rwro && !has_rwro)
+               rc = fsconfig_set_value(cxt, hs, fd, "rw", NULL);
+
+done:
+       DBG(HOOK, ul_debugobj(hs, " config done [rc=%d]", rc));
+       return rc != 0 && errno ? -errno : rc;
 }
 
 static int open_fs_configuration_context(struct libmnt_context *cxt,
@@ -244,7 +262,7 @@ static int hook_create_mount(struct libmnt_context *cxt,
        set_syscall_status(cxt, "fsconfig", rc == 0);
 
        if (!rc)
-               rc = configure_superblock(cxt, hs, api->fd_fs);
+               rc = configure_superblock(cxt, hs, api->fd_fs, 0);
        if (!rc) {
                DBG(HOOK, ul_debugobj(hs, "create FS"));
                rc = fsconfig(api->fd_fs, FSCONFIG_CMD_CREATE, NULL, NULL, 0);
@@ -301,8 +319,9 @@ static int hook_reconfigure_mount(struct libmnt_context *cxt,
                        return -errno;
        }
 
-       rc = configure_superblock(cxt, hs, api->fd_fs);
+       rc = configure_superblock(cxt, hs, api->fd_fs, 1);
        if (!rc) {
+               DBG(HOOK, ul_debugobj(hs, "re-configurate FS"));
                rc = fsconfig(api->fd_fs, FSCONFIG_CMD_RECONFIGURE, NULL, NULL, 0);
                set_syscall_status(cxt, "fsconfig", rc == 0);
        }