ext4: add self-testing infrastructure to do a sanity check

This commit adds a self-testing infrastructure like extent tree does to
do a sanity check for extent status tree.  After status tree is as a
extent cache, we'd better to make sure that it caches right result.

After applied this commit, we will get a lot of messages when we run
xfstests as below.

...
kernel: ES len assertation failed for inode: 230 retval 1 != map->m_len
3 in ext4_map_blocks (allocation)
...
kernel: ES cache assertation failed for inode: 230 es_cached ex
[974/2/4781/20] != found ex [974/1/4781/1000]
...
kernel: ES insert assertation failed for inode: 635 ex_status
[0/45/21388/w] != es_status [44/1/21432/u]
...

Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: Zheng Liu <wenqing.lz@taobao.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

1 files changed, 175 insertions, 0 deletions

diff --git a/fs/ext4/extents_status.c b/fs/ext4/extents_status.c
index 37f9a2d8fd04..d2a8cb74676b 100644
--- a/fs/ext4/extents_status.c
+++ b/fs/ext4/extents_status.c
@@ -399,6 +399,179 @@ ext4_es_try_to_merge_right(struct inode *inode, struct extent_status *es)
         return es;
 }
 
+#ifdef ES_AGGRESSIVE_TEST
+static void ext4_es_insert_extent_ext_check(struct inode *inode,
+                                            struct extent_status *es)
+{
+        struct ext4_ext_path *path = NULL;
+        struct ext4_extent *ex;
+        ext4_lblk_t ee_block;
+        ext4_fsblk_t ee_start;
+        unsigned short ee_len;
+        int depth, ee_status, es_status;
+
+        path = ext4_ext_find_extent(inode, es->es_lblk, NULL);
+        if (IS_ERR(path))
+                return;
+
+        depth = ext_depth(inode);
+        ex = path[depth].p_ext;
+
+        if (ex) {
+
+                ee_block = le32_to_cpu(ex->ee_block);
+                ee_start = ext4_ext_pblock(ex);
+                ee_len = ext4_ext_get_actual_len(ex);
+
+                ee_status = ext4_ext_is_uninitialized(ex) ? 1 : 0;
+                es_status = ext4_es_is_unwritten(es) ? 1 : 0;
+
+                /*
+                 * Make sure ex and es are not overlap when we try to insert
+                 * a delayed/hole extent.
+                 */
+                if (!ext4_es_is_written(es) && !ext4_es_is_unwritten(es)) {
+                        if (in_range(es->es_lblk, ee_block, ee_len)) {
+                                pr_warn("ES insert assertation failed for "
+                                        "inode: %lu we can find an extent "
+                                        "at block [%d/%d/%llu/%c], but we "
+                                        "want to add an delayed/hole extent "
+                                        "[%d/%d/%llu/%llx]\n",
+                                        inode->i_ino, ee_block, ee_len,
+                                        ee_start, ee_status ? 'u' : 'w',
+                                        es->es_lblk, es->es_len,
+                                        ext4_es_pblock(es), ext4_es_status(es));
+                        }
+                        goto out;
+                }
+
+                /*
+                 * We don't check ee_block == es->es_lblk, etc. because es
+                 * might be a part of whole extent, vice versa.
+                 */
+                if (es->es_lblk < ee_block ||
+                    ext4_es_pblock(es) != ee_start + es->es_lblk - ee_block) {
+                        pr_warn("ES insert assertation failed for inode: %lu "
+                                "ex_status [%d/%d/%llu/%c] != "
+                                "es_status [%d/%d/%llu/%c]\n", inode->i_ino,
+                                ee_block, ee_len, ee_start,
+                                ee_status ? 'u' : 'w', es->es_lblk, es->es_len,
+                                ext4_es_pblock(es), es_status ? 'u' : 'w');
+                        goto out;
+                }
+
+                if (ee_status ^ es_status) {
+                        pr_warn("ES insert assertation failed for inode: %lu "
+                                "ex_status [%d/%d/%llu/%c] != "
+                                "es_status [%d/%d/%llu/%c]\n", inode->i_ino,
+                                ee_block, ee_len, ee_start,
+                                ee_status ? 'u' : 'w', es->es_lblk, es->es_len,
+                                ext4_es_pblock(es), es_status ? 'u' : 'w');
+                }
+        } else {
+                /*
+                 * We can't find an extent on disk.  So we need to make sure
+                 * that we don't want to add an written/unwritten extent.
+                 */
+                if (!ext4_es_is_delayed(es) && !ext4_es_is_hole(es)) {
+                        pr_warn("ES insert assertation failed for inode: %lu "
+                                "can't find an extent at block %d but we want "
+                                "to add an written/unwritten extent "
+                                "[%d/%d/%llu/%llx]\n", inode->i_ino,
+                                es->es_lblk, es->es_lblk, es->es_len,
+                                ext4_es_pblock(es), ext4_es_status(es));
+                }
+        }
+out:
+        if (path) {
+                ext4_ext_drop_refs(path);
+                kfree(path);
+        }
+}
+
+static void ext4_es_insert_extent_ind_check(struct inode *inode,
+                                            struct extent_status *es)
+{
+        struct ext4_map_blocks map;
+        int retval;
+
+        /*
+         * Here we call ext4_ind_map_blocks to lookup a block mapping because
+         * 'Indirect' structure is defined in indirect.c.  So we couldn't
+         * access direct/indirect tree from outside.  It is too dirty to define
+         * this function in indirect.c file.
+         */
+
+        map.m_lblk = es->es_lblk;
+        map.m_len = es->es_len;
+
+        retval = ext4_ind_map_blocks(NULL, inode, &map, 0);
+        if (retval > 0) {
+                if (ext4_es_is_delayed(es) || ext4_es_is_hole(es)) {
+                        /*
+                         * We want to add a delayed/hole extent but this
+                         * block has been allocated.
+                         */
+                        pr_warn("ES insert assertation failed for inode: %lu "
+                                "We can find blocks but we want to add a "
+                                "delayed/hole extent [%d/%d/%llu/%llx]\n",
+                                inode->i_ino, es->es_lblk, es->es_len,
+                                ext4_es_pblock(es), ext4_es_status(es));
+                        return;
+                } else if (ext4_es_is_written(es)) {
+                        if (retval != es->es_len) {
+                                pr_warn("ES insert assertation failed for "
+                                        "inode: %lu retval %d != es_len %d\n",
+                                        inode->i_ino, retval, es->es_len);
+                                return;
+                        }
+                        if (map.m_pblk != ext4_es_pblock(es)) {
+                                pr_warn("ES insert assertation failed for "
+                                        "inode: %lu m_pblk %llu != "
+                                        "es_pblk %llu\n",
+                                        inode->i_ino, map.m_pblk,
+                                        ext4_es_pblock(es));
+                                return;
+                        }
+                } else {
+                        /*
+                         * We don't need to check unwritten extent because
+                         * indirect-based file doesn't have it.
+                         */
+                        BUG_ON(1);
+                }
+        } else if (retval == 0) {
+                if (ext4_es_is_written(es)) {
+                        pr_warn("ES insert assertation failed for inode: %lu "
+                                "We can't find the block but we want to add "
+                                "an written extent [%d/%d/%llu/%llx]\n",
+                                inode->i_ino, es->es_lblk, es->es_len,
+                                ext4_es_pblock(es), ext4_es_status(es));
+                        return;
+                }
+        }
+}
+
+static inline void ext4_es_insert_extent_check(struct inode *inode,
+                                               struct extent_status *es)
+{
+        /*
+         * We don't need to worry about the race condition because
+         * caller takes i_data_sem locking.
+         */
+        BUG_ON(!rwsem_is_locked(&EXT4_I(inode)->i_data_sem));
+        if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
+                ext4_es_insert_extent_ext_check(inode, es);
+        else
+                ext4_es_insert_extent_ind_check(inode, es);
+}
+#else
+static inline void ext4_es_insert_extent_check(struct inode *inode,
+                                               struct extent_status *es)
+{
+}
+#endif
+
 static int __es_insert_extent(struct inode *inode, struct extent_status *newes)
 {
         struct ext4_es_tree *tree = &EXT4_I(inode)->i_es_tree;
@@ -481,6 +654,8 @@ int ext4_es_insert_extent(struct inode *inode, ext4_lblk_t lblk,
         ext4_es_store_status(&newes, status);
         trace_ext4_es_insert_extent(inode, &newes);
 
+        ext4_es_insert_extent_check(inode, &newes);
+
         write_lock(&EXT4_I(inode)->i_es_lock);
         err = __es_remove_extent(inode, lblk, end);
         if (err != 0)