File util-linux-libmount-btrfs-subvolid-3.patch of Package util-linux.2662
From 9aa3173bab816dfa88972dc12d4b54b9dfce7177 Mon Sep 17 00:00:00 2001
From: Karel Zak <kzak@redhat.com>
Date: Mon, 1 Feb 2016 13:10:33 +0100
Subject: [PATCH] libmount: move btrfs subvol code refactoring
Signed-off-by: Karel Zak <kzak@redhat.com>
---
libmount/src/tab.c | 214 ++++++++++++++++++++++++++++-------------------------
1 file changed, 115 insertions(+), 99 deletions(-)
Index: util-linux-2.25/libmount/src/tab.c
===================================================================
--- util-linux-2.25.orig/libmount/src/tab.c
+++ util-linux-2.25/libmount/src/tab.c
@@ -1278,6 +1278,120 @@ static char *remove_mountpoint_from_path
return res;
}
+#ifdef HAVE_BTRFS_SUPPORT
+static int get_btrfs_fs_root(struct libmnt_table *tb, struct libmnt_fs *fs, char **root)
+{
+ char *vol = NULL, *p;
+ size_t sz, volsz = 0;
+
+ DBG(BTRFS, ul_debug("lookup for btrfs FS root"));
+ *root = NULL;
+
+ if (mnt_fs_get_option(fs, "subvolid", &vol, &volsz) == 0) {
+ 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_target(mnt_fs_get_target(fs), tb->cache);
+ if (!target)
+ goto err;
+
+ 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);
+ if (!tb->cache)
+ free(target);
+ if (!f)
+ goto not_found;
+
+ /* Instead of set of BACKREF queries constructing subvol path
+ * corresponding to a particular subvolid, use the one in
+ * mountinfo. Kernel keeps subvol path up to date.
+ */
+ if (mnt_fs_get_option(f, "subvol", &vol, &volsz) != 0)
+ goto not_found;
+
+ } else 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.
+ */
+ uint64_t default_id;
+ char *target;
+ struct libmnt_fs *f;
+ char default_id_str[sizeof(stringify_value(UINT64_MAX))];
+
+ DBG(BTRFS, ul_debug(" subvolid/subvol not found, checking default"));
+
+ default_id = btrfs_get_default_subvol_id(mnt_fs_get_target(fs));
+ if (default_id == UINT64_MAX)
+ goto not_found;
+
+ /* Volume has default subvolume. Check if it matches to
+ * the one in mountinfo.
+ *
+ * Only kernel >= 4.2 reports subvolid. On older
+ * kernels, there is no reasonable way to detect which
+ * subvolume was mounted.
+ */
+ 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(" 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);
+ if (!tb->cache)
+ free(target);
+ if (!f)
+ goto not_found;
+
+ /* Instead of set of BACKREF queries constructing
+ * subvol path, use the one in mountinfo. Kernel does
+ * the evaluation for us.
+ */
+ DBG(BTRFS, ul_debug("setting FS root: btrfs default subvolid = %s",
+ default_id_str));
+
+ if (mnt_fs_get_option(f, "subvol", &vol, &volsz) != 0)
+ goto not_found;
+ }
+
+ DBG(BTRFS, ul_debug(" using subvol=%s", vol));
+ sz = volsz;
+ if (*vol != '/')
+ sz++;
+ *root = malloc(sz + 1);
+ if (!*root)
+ goto err;
+ p = *root;
+ if (*vol != '/')
+ *p++ = '/';
+ memcpy(p, vol, volsz);
+ *(*root + sz) = '\0';
+ return 0;
+
+not_found:
+ DBG(BTRFS, ul_debug(" not found btrfs volume setting"));
+ return 1;
+err:
+ DBG(BTRFS, ul_debug(" error on btrfs volume setting evaluation"));
+ return errno ? -errno : -1;
+}
+#endif /* HAVE_BTRFS_SUPPORT */
+
/*
* tb: /proc/self/mountinfo
* fs: filesystem
@@ -1374,106 +1488,8 @@ struct libmnt_fs *mnt_table_get_fs_root(
* btrfs-subvolume mount -- get subvolume name and use it as a root-fs path
*/
else if (fstype && (!strcmp(fstype, "btrfs") || !strcmp(fstype, "auto"))) {
- char *vol = NULL, *p;
- size_t sz, volsz = 0;
-
- DBG(BTRFS, ul_debug("lookup for btrfs FS root"));
-
- 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.
- */
- uint64_t default_id;
- char *target;
- 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;
-
- /* Volume has default subvolume. Check if it
- * matches to the one in mountinfo.
- *
- * Only kernel >= 4.2 reports subvolid. On older
- * kernels, there is no reasonable way to detect
- * which subvolume was mounted.
- */
- 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(" 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);
- if (!tb->cache)
- free(target);
- if (!f)
- goto dflt;
-
- /* Instead of set of BACKREF queries constructing
- * subvol path, use the one in mountinfo. Kernel
- * does the evaluation for us. */
- DBG(BTRFS, ul_debug("setting FS root: btrfs default subvolid = %s", default_id_str));
- if (mnt_fs_get_option(f, "subvol", &vol, &volsz))
- goto dflt;
- } else
- 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_target(mnt_fs_get_target(fs), tb->cache);
- if (!target)
- goto err;
-
- 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);
- if (!tb->cache)
- free(target);
-
- if (!f)
- goto dflt;
-
- /* Instead of set of BACKREF queries constructing
- * subvol path corresponding to a particular subvolid,
- * use the one in mountinfo. Kernel keeps subvol path
- * up to date.
- */
- if (mnt_fs_get_option(f, "subvol", &vol, &volsz))
- goto dflt;
-
- DBG(BTRFS, ul_debug(" found subvol=%s", vol));
- }
-
- sz = volsz;
- if (*vol != '/')
- sz++;
- root = malloc(sz + 1);
- if (!root)
+ if (get_btrfs_fs_root(tb, fs, &root) < 0)
goto err;
- p = root;
- if (*vol != '/')
- *p++ = '/';
- memcpy(p, vol, volsz);
- *(root + sz) = '\0';
}
#endif /* HAVE_BTRFS_SUPPORT */
