ext4: handle add_system_zone() failure in ext4_setup_system_zone()

There's one place that fails to handle error from add_system_zone() call
and thus we can fail to protect superblock and group-descriptor blocks
properly in case of ENOMEM. Fix it.

Reported-by: Lukas Czerner <lczerner@redhat.com>
Reviewed-by: Lukas Czerner <lczerner@redhat.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20200728130437.7804-6-jack@suse.cz
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

diff --git a/fs/ext4/block_validity.c b/fs/ext4/block_validity.c
index 9c40214..2d008c1 100644 (file)
--- a/fs/ext4/block_validity.c
+++ b/fs/ext4/block_validity.c
@@ -235,10 +235,13 @@ int ext4_setup_system_zone(struct super_block *sb)
        for (i=0; i < ngroups; i++) {
                cond_resched();
                if (ext4_bg_has_super(sb, i) &&
-                   ((i < 5) || ((i % flex_size) == 0)))
-                       add_system_zone(system_blks,
+                   ((i < 5) || ((i % flex_size) == 0))) {
+                       ret = add_system_zone(system_blks,
                                        ext4_group_first_block_no(sb, i),
                                        ext4_bg_num_gdb(sb, i) + 1, 0);
+                       if (ret)
+                               goto err;
+               }
                gdp = ext4_get_group_desc(sb, i, NULL);
                ret = add_system_zone(system_blks,
                                ext4_block_bitmap(sb, gdp), 1, 0);