btrfs: use verbose assertions in backref.c

While debugging a relocation issue I hit an assertion in backref.c but it
was not super useful, since it could not tell what was the unexpected
value that triggered the assertion. The stack trace was this:

  [583246.338097] assertion failed: !cache->nr_nodes, in fs/btrfs/backref.c:3158
  [583246.339588] ------------[ cut here ]------------
  [583246.340573] kernel BUG at fs/btrfs/backref.c:3158!
  [583246.342075] Oops: invalid opcode: 0000 [#1] SMP PTI
  [583246.343294] CPU: 5 UID: 0 PID: 677957 Comm: btrfs Not tainted 7.1.0-rc4-btrfs-next-234+ #1 PREEMPT(full)
  [583246.345715] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.2-0-gea1b7a073390-prebuilt.qemu.org 04/01/2014
  [583246.348694] RIP: 0010:btrfs_backref_release_cache.cold+0x61/0x84 [btrfs]
  [583246.350759] Code: 90 d5 7c (...)
  [583246.354923] RSP: 0018:ffffd4fc88c93ad8 EFLAGS: 00010246
  [583246.355982] RAX: 000000000000003e RBX: ffff8dec90d97020 RCX: 0000000000000000
  [583246.357459] RDX: 0000000000000000 RSI: 0000000000000001 RDI: 00000000ffffffff
  [583246.359517] RBP: ffff8dec8eeb78c0 R08: 0000000000000000 R09: 3fffffffffefffff
  [583246.361180] R10: ffffd4fc88c93970 R11: 0000000000000003 R12: ffff8decd21f3470
  [583246.363184] R13: 00000000fffffffe R14: ffff8decd21f3000 R15: ffff8decd21f3000
  [583246.364666] FS:  00007f9a51751400(0000) GS:ffff8df3f4255000(0000) knlGS:0000000000000000
  [583246.366287] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  [583246.367443] CR2: 00007f9a518ed8f5 CR3: 00000004467c8002 CR4: 0000000000370ef0
  [583246.368969] Call Trace:
  [583246.369541]  <TASK>
  [583246.370040]  relocate_block_group+0xf2/0x520 [btrfs]
  [583246.371243]  btrfs_relocate_block_group+0x9a9/0x22e0 [btrfs]
  [583246.372443]  ? preempt_count_add+0x47/0xa0
  [583247.532978]  ? btrfs_tree_read_lock_nested+0x19/0x90 [btrfs]
  [583247.534520]  ? mutex_lock+0x1a/0x40
  [583247.602233]  ? btrfs_scrub_pause+0x2e/0x120 [btrfs]
  [583247.603543]  btrfs_relocate_chunk+0x3b/0x1a0 [btrfs]
  [583247.604893]  btrfs_balance+0x9d5/0x1920 [btrfs]
  [583247.606189]  ? preempt_count_add+0x69/0xa0
  [583247.607030]  btrfs_ioctl+0x260c/0x2a20 [btrfs]
  [583247.608015]  ? __memcg_slab_free_hook+0x156/0x1a0
  [583247.636971]  __x64_sys_ioctl+0x92/0xe0
  [583247.679247]  do_syscall_64+0x60/0xf20
  [583247.753297]  ? clear_bhb_loop+0x60/0xb0
  [583247.756321]  entry_SYSCALL_64_after_hwframe+0x76/0x7e
  [583247.787018] RIP: 0033:0x7f9a5186a8db
  [583247.787787] Code: 00 48 89 (...)
  [583247.791410] RSP: 002b:00007fff2ffa6ac0 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
  [583247.792897] RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f9a5186a8db
  [583247.794319] RDX: 00007fff2ffa6bb0 RSI: 00000000c4009420 RDI: 0000000000000003
  [583247.795714] RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
  [583247.797149] R10: 0000000000000000 R11: 0000000000000246 R12: 00007fff2ffa903f
  [583247.798685] R13: 00007fff2ffa6bb0 R14: 0000000000000002 R15: 0000000000000002
  [583247.800136]  </TASK>

So update all simple assertions in backref.c to print out the values when
they aren't testing simple boolean conditions.

Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/backref.c b/fs/btrfs/backref.c
index 0abcec0ceead0c02d39935623ee6de9770023669..23c3eeb58dc1d4ee6a9bb0d203c3108e5a911a52 100644 (file)
--- a/fs/btrfs/backref.c
+++ b/fs/btrfs/backref.c
@@ -1256,7 +1256,7 @@ static bool lookup_backref_shared_cache(struct btrfs_backref_share_check_ctx *ct
         * realizing. We cache results only for extent buffers that lead from
         * the root node down to the leaf with the file extent item.
         */
-       ASSERT(level >= 0);
+       ASSERT(level >= 0, "level=%d", level);
 
        entry = &ctx->path_cache_entries[level];
 
@@ -1327,7 +1327,7 @@ static void store_backref_shared_cache(struct btrfs_backref_share_check_ctx *ctx
         * realizing. We cache results only for extent buffers that lead from
         * the root node down to the leaf with the file extent item.
         */
-       ASSERT(level >= 0);
+       ASSERT(level >= 0, "level=%d", level);
 
        if (is_shared)
                gen = btrfs_get_last_root_drop_gen(fs_info);
@@ -2964,7 +2964,9 @@ int btrfs_backref_iter_next(struct btrfs_fs_info *fs_info, struct btrfs_backref_
 
        if (btrfs_backref_iter_is_inline_ref(iter)) {
                /* We're still inside the inline refs */
-               ASSERT(iter->cur_ptr < iter->end_ptr);
+               ASSERT(iter->cur_ptr < iter->end_ptr,
+                      "iter->cur_ptr=%u iter->end_ptr=%u",
+                      iter->cur_ptr, iter->end_ptr);
 
                if (btrfs_backref_has_tree_block_info(iter)) {
                        /* First tree block info */
@@ -3030,7 +3032,7 @@ struct btrfs_backref_node *btrfs_backref_alloc_node(
 {
        struct btrfs_backref_node *node;
 
-       ASSERT(level >= 0 && level < BTRFS_MAX_LEVEL);
+       ASSERT(level >= 0 && level < BTRFS_MAX_LEVEL, "level=%d", level);
        node = kzalloc_obj(*node, GFP_NOFS);
        if (!node)
                return node;
@@ -3052,7 +3054,7 @@ void btrfs_backref_free_node(struct btrfs_backref_cache *cache,
        if (node) {
                ASSERT(list_empty(&node->list));
                ASSERT(list_empty(&node->lower));
-               ASSERT(node->eb == NULL);
+               ASSERT(node->eb == NULL, "node->eb->start=%llu", node->eb->start);
                cache->nr_nodes--;
                btrfs_put_root(node->root);
                kfree(node);
@@ -3155,15 +3157,18 @@ void btrfs_backref_release_cache(struct btrfs_backref_cache *cache)
 
        ASSERT(list_empty(&cache->pending_edge));
        ASSERT(list_empty(&cache->useless_node));
-       ASSERT(!cache->nr_nodes);
-       ASSERT(!cache->nr_edges);
+       ASSERT(!cache->nr_nodes, "cache->nr_nodes=%d", cache->nr_nodes);
+       ASSERT(!cache->nr_edges, "cache->nr_edges=%d", cache->nr_edges);
 }
 
 static void btrfs_backref_link_edge(struct btrfs_backref_edge *edge,
                                    struct btrfs_backref_node *lower,
                                    struct btrfs_backref_node *upper)
 {
-       ASSERT(upper && lower && upper->level == lower->level + 1);
+       ASSERT(upper != NULL);
+       ASSERT(lower != NULL);
+       ASSERT(upper->level == lower->level + 1, "upper->level=%d lower->level=%d",
+              upper->level, lower->level);
        edge->node[LOWER] = lower;
        edge->node[UPPER] = upper;
        list_add_tail(&edge->list[LOWER], &lower->upper);
@@ -3283,7 +3288,9 @@ static int handle_indirect_tree_backref(struct btrfs_trans_handle *trans,
 
        if (btrfs_root_level(&root->root_item) == cur->level) {
                /* Tree root */
-               ASSERT(btrfs_root_bytenr(&root->root_item) == cur->bytenr);
+               ASSERT(btrfs_root_bytenr(&root->root_item) == cur->bytenr,
+                      "root_bytenr=%llu cur->bytenr=%llu",
+                      btrfs_root_bytenr(&root->root_item), cur->bytenr);
                /*
                 * For reloc backref cache, we may ignore reloc root.  But for
                 * general purpose backref cache, we can't rely on
@@ -3333,8 +3340,9 @@ static int handle_indirect_tree_backref(struct btrfs_trans_handle *trans,
        /* Add all nodes and edges in the path */
        for (; level < BTRFS_MAX_LEVEL; level++) {
                if (!path->nodes[level]) {
-                       ASSERT(btrfs_root_bytenr(&root->root_item) ==
-                              lower->bytenr);
+                       ASSERT(btrfs_root_bytenr(&root->root_item) == lower->bytenr,
+                              "root_bytenr=%llu lower->bytenr=%llu",
+                              btrfs_root_bytenr(&root->root_item), lower->bytenr);
                        /* Same as previous should_ignore_reloc_root() call */
                        if (btrfs_should_ignore_reloc_root(root) &&
                            cache->is_reloc) {