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>

3 files changed, 277 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)
diff --git a/fs/ext4/extents_status.h b/fs/ext4/extents_status.h
index f190dfe969da..56140ad4150b 100644
--- a/fs/ext4/extents_status.h
+++ b/fs/ext4/extents_status.h
@@ -21,6 +21,12 @@
 #endif
 
 /*
+ * With ES_AGGRESSIVE_TEST defined, the result of es caching will be
+ * checked with old map_block's result.
+ */
+#define ES_AGGRESSIVE_TEST__
+
+/*
  * These flags live in the high bits of extent_status.es_pblk
  */
 #define EXTENT_STATUS_WRITTEN   (1ULL << 63)
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 95a0c62c5683..3186a43fa4b0 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -482,6 +482,58 @@ static pgoff_t ext4_num_dirty_pages(struct inode *inode, pgoff_t idx,
         return num;
 }
 
+#ifdef ES_AGGRESSIVE_TEST
+static void ext4_map_blocks_es_recheck(handle_t *handle,
+                                       struct inode *inode,
+                                       struct ext4_map_blocks *es_map,
+                                       struct ext4_map_blocks *map,
+                                       int flags)
+{
+        int retval;
+
+        map->m_flags = 0;
+        /*
+         * There is a race window that the result is not the same.
+         * e.g. xfstests #223 when dioread_nolock enables.  The reason
+         * is that we lookup a block mapping in extent status tree with
+         * out taking i_data_sem.  So at the time the unwritten extent
+         * could be converted.
+         */
+        if (!(flags & EXT4_GET_BLOCKS_NO_LOCK))
+                down_read((&EXT4_I(inode)->i_data_sem));
+        if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
+                retval = ext4_ext_map_blocks(handle, inode, map, flags &
+                                             EXT4_GET_BLOCKS_KEEP_SIZE);
+        } else {
+                retval = ext4_ind_map_blocks(handle, inode, map, flags &
+                                             EXT4_GET_BLOCKS_KEEP_SIZE);
+        }
+        if (!(flags & EXT4_GET_BLOCKS_NO_LOCK))
+                up_read((&EXT4_I(inode)->i_data_sem));
+        /*
+         * Clear EXT4_MAP_FROM_CLUSTER and EXT4_MAP_BOUNDARY flag
+         * because it shouldn't be marked in es_map->m_flags.
+         */
+        map->m_flags &= ~(EXT4_MAP_FROM_CLUSTER | EXT4_MAP_BOUNDARY);
+
+        /*
+         * We don't check m_len because extent will be collpased in status
+         * tree.  So the m_len might not equal.
+         */
+        if (es_map->m_lblk != map->m_lblk ||
+            es_map->m_flags != map->m_flags ||
+            es_map->m_pblk != map->m_pblk) {
+                printk("ES cache assertation failed for inode: %lu "
+                       "es_cached ex [%d/%d/%llu/%x] != "
+                       "found ex [%d/%d/%llu/%x] retval %d flags %x\n",
+                       inode->i_ino, es_map->m_lblk, es_map->m_len,
+                       es_map->m_pblk, es_map->m_flags, map->m_lblk,
+                       map->m_len, map->m_pblk, map->m_flags,
+                       retval, flags);
+        }
+}
+#endif /* ES_AGGRESSIVE_TEST */
+
 /*
  * The ext4_map_blocks() function tries to look up the requested blocks,
  * and returns if the blocks are already mapped.
@@ -509,6 +561,11 @@ int ext4_map_blocks(handle_t *handle, struct inode *inode,
 {
         struct extent_status es;
         int retval;
+#ifdef ES_AGGRESSIVE_TEST
+        struct ext4_map_blocks orig_map;
+
+        memcpy(&orig_map, map, sizeof(*map));
+#endif
 
         map->m_flags = 0;
         ext_debug("ext4_map_blocks(): inode %lu, flag %d, max_blocks %u,"
@@ -531,6 +588,10 @@ int ext4_map_blocks(handle_t *handle, struct inode *inode,
                 } else {
                         BUG_ON(1);
                 }
+#ifdef ES_AGGRESSIVE_TEST
+                ext4_map_blocks_es_recheck(handle, inode, map,
+                                           &orig_map, flags);
+#endif
                 goto found;
         }
 
@@ -551,6 +612,15 @@ int ext4_map_blocks(handle_t *handle, struct inode *inode,
                 int ret;
                 unsigned long long status;
 
+#ifdef ES_AGGRESSIVE_TEST
+                if (retval != map->m_len) {
+                        printk("ES len assertation failed for inode: %lu "
+                               "retval %d != map->m_len %d "
+                               "in %s (lookup)\n", inode->i_ino, retval,
+                               map->m_len, __func__);
+                }
+#endif
+
                 status = map->m_flags & EXT4_MAP_UNWRITTEN ?
                                 EXTENT_STATUS_UNWRITTEN : EXTENT_STATUS_WRITTEN;
                 if (!(flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) &&
@@ -643,6 +713,15 @@ found:
                 int ret;
                 unsigned long long status;
 
+#ifdef ES_AGGRESSIVE_TEST
+                if (retval != map->m_len) {
+                        printk("ES len assertation failed for inode: %lu "
+                               "retval %d != map->m_len %d "
+                               "in %s (allocation)\n", inode->i_ino, retval,
+                               map->m_len, __func__);
+                }
+#endif
+
                 status = map->m_flags & EXT4_MAP_UNWRITTEN ?
                                 EXTENT_STATUS_UNWRITTEN : EXTENT_STATUS_WRITTEN;
                 if (!(flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) &&
@@ -1768,6 +1847,11 @@ static int ext4_da_map_blocks(struct inode *inode, sector_t iblock,
         struct extent_status es;
         int retval;
         sector_t invalid_block = ~((sector_t) 0xffff);
+#ifdef ES_AGGRESSIVE_TEST
+        struct ext4_map_blocks orig_map;
+
+        memcpy(&orig_map, map, sizeof(*map));
+#endif
 
         if (invalid_block < ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es))
                 invalid_block = ~0;
@@ -1809,6 +1893,9 @@ static int ext4_da_map_blocks(struct inode *inode, sector_t iblock,
                 else
                         BUG_ON(1);
 
+#ifdef ES_AGGRESSIVE_TEST
+                ext4_map_blocks_es_recheck(NULL, inode, map, &orig_map, 0);
+#endif
                 return retval;
         }
 
@@ -1873,6 +1960,15 @@ add_delayed:
                 int ret;
                 unsigned long long status;
 
+#ifdef ES_AGGRESSIVE_TEST
+                if (retval != map->m_len) {
+                        printk("ES len assertation failed for inode: %lu "
+                               "retval %d != map->m_len %d "
+                               "in %s (lookup)\n", inode->i_ino, retval,
+                               map->m_len, __func__);
+                }
+#endif
+
                 status = map->m_flags & EXT4_MAP_UNWRITTEN ?
                                 EXTENT_STATUS_UNWRITTEN : EXTENT_STATUS_WRITTEN;
                 ret = ext4_es_insert_extent(inode, map->m_lblk, map->m_len,