libmount: fix target resolving for btrfs stuff

and make the code more verbose.

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

diff --git a/libmount/src/tab.c b/libmount/src/tab.c
index 845ec6c724ae06361b2acaf57e52edfce63b7988..b2a8d7fd47ead9ca413cd03be2c09f0c21943b51 100644 (file)
--- a/libmount/src/tab.c
+++ b/libmount/src/tab.c
@@ -1267,7 +1267,6 @@ struct libmnt_fs *mnt_table_get_fs_root(struct libmnt_table *tb,
                        if (f)
                                mnt = mnt_fs_get_target(f);
                }
-
                if (mnt)
                        root = remove_mountpoint_from_path(src, mnt);
 
@@ -1323,10 +1322,10 @@ struct libmnt_fs *mnt_table_get_fs_root(struct libmnt_table *tb,
                char *vol = NULL, *p;
                size_t sz, volsz = 0;
 
-               DBG(BTRFS, ul_debug("lookup for FS root"));
+               DBG(BTRFS, ul_debug("lookup for btrfs FS root"));
 
-               if (mnt_fs_get_option(fs, "subvolid", &vol, &volsz)) {
-                       if (mnt_fs_get_option(fs, "subvol", &vol, &volsz)) {
+               if (mnt_fs_get_option(fs, "subvolid", &vol, &volsz) != 0) {
+                       if (mnt_fs_get_option(fs, "subvol", &vol, &volsz) != 0) {
                                /* If fstab entry does not contain "subvol", we
                                 * have to check, whether btrfs has default
                                 * subvolume defined.
@@ -1336,6 +1335,8 @@ struct libmnt_fs *mnt_table_get_fs_root(struct libmnt_table *tb,
                                struct libmnt_fs *f;
                                char default_id_str[sizeof(stringify_value(UINT64_MAX))];
 
+                               DBG(BTRFS, ul_debug(" subvolid/subvol not set, checking default"));
+
                                default_id = btrfs_get_default_subvol_id(mnt_fs_get_target(fs));
                                if (default_id == UINT64_MAX)
                                        goto dflt;
@@ -1347,14 +1348,14 @@ struct libmnt_fs *mnt_table_get_fs_root(struct libmnt_table *tb,
                                 * kernels, there is no reasonable way to detect
                                 * which subvolume was mounted.
                                 */
-                               target = mnt_resolve_spec(mnt_fs_get_target(fs), tb->cache);
+                               target = mnt_resolve_target(mnt_fs_get_target(fs), tb->cache);
                                if (!target)
                                        goto err;
 
                                snprintf(default_id_str, sizeof(default_id_str), "%llu",
                                                (unsigned long long int) default_id);
 
-                               DBG(BTRFS, ul_debug("target=%s default subvolid=%s", target, default_id_str));
+                               DBG(BTRFS, ul_debug(" tring target=%s default subvolid=%s", target, default_id_str));
                                f = mnt_table_find_target_with_option(tb, target,
                                                        "subvolid", default_id_str,
                                                        MNT_ITER_BACKWARD);
@@ -1370,21 +1371,23 @@ struct libmnt_fs *mnt_table_get_fs_root(struct libmnt_table *tb,
                                if (mnt_fs_get_option(f, "subvol", &vol, &volsz))
                                        goto dflt;
                        } else
-                               DBG(BTRFS, ul_debug("setting FS root: btrfs subvol"));
+                               DBG(BTRFS, ul_debug(" found subvol=%s", vol));
                } else {
                        char *target;
                        struct libmnt_fs *f;
                        char subvolidstr[sizeof(stringify_value(UINT64_MAX))];
 
+                       DBG(BTRFS, ul_debug(" found subvolid=%s, checking", vol));
+
                        assert (volsz + 1 < sizeof(stringify_value(UINT64_MAX)));
                        memcpy(subvolidstr, vol, volsz);
                        subvolidstr[volsz] = '\0';
 
-                       target = mnt_resolve_spec(mnt_fs_get_target(fs), tb->cache);
+                       target = mnt_resolve_target(mnt_fs_get_target(fs), tb->cache);
                        if (!target)
                                goto err;
 
-                       DBG(BTRFS, ul_debug("target=%s subvolid=%s", target, subvolidstr));
+                       DBG(BTRFS, ul_debug(" tring target=%s subvolid=%s", target, subvolidstr));
                        f = mnt_table_find_target_with_option(tb, target,
                                                "subvolid", subvolidstr,
                                                MNT_ITER_BACKWARD);
@@ -1401,6 +1404,8 @@ struct libmnt_fs *mnt_table_get_fs_root(struct libmnt_table *tb,
                         */
                        if (mnt_fs_get_option(f, "subvol", &vol, &volsz))
                                goto dflt;
+
+                       DBG(BTRFS, ul_debug(" found subvol=%s", vol));
                }
 
                sz = volsz;