[PATCH AUTOSEL 5.15 17/20] btrfs: move lockdep class helpers to locking.c

[PATCH AUTOSEL 5.15 17/20] btrfs: move lockdep class helpers to locking.c

[Sasha Levin]

From: Josef Bacik <josef@toxicpanda.com>

[ Upstream commit 0a27a0474d146eb79e09ec88bf0d4229f4cfc1b8 ]

These definitions exist in disk-io.c, which is not related to the
locking.  Move this over to locking.h/c where it makes more sense.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/btrfs/disk-io.c | 82 ----------------------------------------------
 fs/btrfs/disk-io.h | 10 ------
 fs/btrfs/locking.c | 80 ++++++++++++++++++++++++++++++++++++++++++++
 fs/btrfs/locking.h |  9 +++++
 4 files changed, 89 insertions(+), 92 deletions(-)

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index e65c3039caf1..c9edc668b3d9 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -121,88 +121,6 @@ struct async_submit_bio {
 	blk_status_t status;
 };
 
-/*
- * Lockdep class keys for extent_buffer->lock's in this root.  For a given
- * eb, the lockdep key is determined by the btrfs_root it belongs to and
- * the level the eb occupies in the tree.
- *
- * Different roots are used for different purposes and may nest inside each
- * other and they require separate keysets.  As lockdep keys should be
- * static, assign keysets according to the purpose of the root as indicated
- * by btrfs_root->root_key.objectid.  This ensures that all special purpose
- * roots have separate keysets.
- *
- * Lock-nesting across peer nodes is always done with the immediate parent
- * node locked thus preventing deadlock.  As lockdep doesn't know this, use
- * subclass to avoid triggering lockdep warning in such cases.
- *
- * The key is set by the readpage_end_io_hook after the buffer has passed
- * csum validation but before the pages are unlocked.  It is also set by
- * btrfs_init_new_buffer on freshly allocated blocks.
- *
- * We also add a check to make sure the highest level of the tree is the
- * same as our lockdep setup here.  If BTRFS_MAX_LEVEL changes, this code
- * needs update as well.
- */
-#ifdef CONFIG_DEBUG_LOCK_ALLOC
-# if BTRFS_MAX_LEVEL != 8
-#  error
-# endif
-
-#define DEFINE_LEVEL(stem, level)					\
-	.names[level] = "btrfs-" stem "-0" #level,
-
-#define DEFINE_NAME(stem)						\
-	DEFINE_LEVEL(stem, 0)						\
-	DEFINE_LEVEL(stem, 1)						\
-	DEFINE_LEVEL(stem, 2)						\
-	DEFINE_LEVEL(stem, 3)						\
-	DEFINE_LEVEL(stem, 4)						\
-	DEFINE_LEVEL(stem, 5)						\
-	DEFINE_LEVEL(stem, 6)						\
-	DEFINE_LEVEL(stem, 7)
-
-static struct btrfs_lockdep_keyset {
-	u64			id;		/* root objectid */
-	/* Longest entry: btrfs-free-space-00 */
-	char			names[BTRFS_MAX_LEVEL][20];
-	struct lock_class_key	keys[BTRFS_MAX_LEVEL];
-} btrfs_lockdep_keysets[] = {
-	{ .id = BTRFS_ROOT_TREE_OBJECTID,	DEFINE_NAME("root")	},
-	{ .id = BTRFS_EXTENT_TREE_OBJECTID,	DEFINE_NAME("extent")	},
-	{ .id = BTRFS_CHUNK_TREE_OBJECTID,	DEFINE_NAME("chunk")	},
-	{ .id = BTRFS_DEV_TREE_OBJECTID,	DEFINE_NAME("dev")	},
-	{ .id = BTRFS_CSUM_TREE_OBJECTID,	DEFINE_NAME("csum")	},
-	{ .id = BTRFS_QUOTA_TREE_OBJECTID,	DEFINE_NAME("quota")	},
-	{ .id = BTRFS_TREE_LOG_OBJECTID,	DEFINE_NAME("log")	},
-	{ .id = BTRFS_TREE_RELOC_OBJECTID,	DEFINE_NAME("treloc")	},
-	{ .id = BTRFS_DATA_RELOC_TREE_OBJECTID,	DEFINE_NAME("dreloc")	},
-	{ .id = BTRFS_UUID_TREE_OBJECTID,	DEFINE_NAME("uuid")	},
-	{ .id = BTRFS_FREE_SPACE_TREE_OBJECTID,	DEFINE_NAME("free-space") },
-	{ .id = 0,				DEFINE_NAME("tree")	},
-};
-
-#undef DEFINE_LEVEL
-#undef DEFINE_NAME
-
-void btrfs_set_buffer_lockdep_class(u64 objectid, struct extent_buffer *eb,
-				    int level)
-{
-	struct btrfs_lockdep_keyset *ks;
-
-	BUG_ON(level >= ARRAY_SIZE(ks->keys));
-
-	/* find the matching keyset, id 0 is the default entry */
-	for (ks = btrfs_lockdep_keysets; ks->id; ks++)
-		if (ks->id == objectid)
-			break;
-
-	lockdep_set_class_and_name(&eb->lock,
-				   &ks->keys[level], ks->names[level]);
-}
-
-#endif
-
 /*
  * Compute the csum of a btree block and store the result to provided buffer.
  */
diff --git a/fs/btrfs/disk-io.h b/fs/btrfs/disk-io.h
index 0e7e9526b6a8..1b8fd3deafc9 100644
--- a/fs/btrfs/disk-io.h
+++ b/fs/btrfs/disk-io.h
@@ -140,14 +140,4 @@ int btrfs_init_root_free_objectid(struct btrfs_root *root);
 int __init btrfs_end_io_wq_init(void);
 void __cold btrfs_end_io_wq_exit(void);
 
-#ifdef CONFIG_DEBUG_LOCK_ALLOC
-void btrfs_set_buffer_lockdep_class(u64 objectid,
-			            struct extent_buffer *eb, int level);
-#else
-static inline void btrfs_set_buffer_lockdep_class(u64 objectid,
-					struct extent_buffer *eb, int level)
-{
-}
-#endif
-
 #endif
diff --git a/fs/btrfs/locking.c b/fs/btrfs/locking.c
index 33461b4f9c8b..5747c63929df 100644
--- a/fs/btrfs/locking.c
+++ b/fs/btrfs/locking.c
@@ -13,6 +13,86 @@
 #include "extent_io.h"
 #include "locking.h"
 
+/*
+ * Lockdep class keys for extent_buffer->lock's in this root.  For a given
+ * eb, the lockdep key is determined by the btrfs_root it belongs to and
+ * the level the eb occupies in the tree.
+ *
+ * Different roots are used for different purposes and may nest inside each
+ * other and they require separate keysets.  As lockdep keys should be
+ * static, assign keysets according to the purpose of the root as indicated
+ * by btrfs_root->root_key.objectid.  This ensures that all special purpose
+ * roots have separate keysets.
+ *
+ * Lock-nesting across peer nodes is always done with the immediate parent
+ * node locked thus preventing deadlock.  As lockdep doesn't know this, use
+ * subclass to avoid triggering lockdep warning in such cases.
+ *
+ * The key is set by the readpage_end_io_hook after the buffer has passed
+ * csum validation but before the pages are unlocked.  It is also set by
+ * btrfs_init_new_buffer on freshly allocated blocks.
+ *
+ * We also add a check to make sure the highest level of the tree is the
+ * same as our lockdep setup here.  If BTRFS_MAX_LEVEL changes, this code
+ * needs update as well.
+ */
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+#if BTRFS_MAX_LEVEL != 8
+#error
+#endif
+
+#define DEFINE_LEVEL(stem, level)					\
+	.names[level] = "btrfs-" stem "-0" #level,
+
+#define DEFINE_NAME(stem)						\
+	DEFINE_LEVEL(stem, 0)						\
+	DEFINE_LEVEL(stem, 1)						\
+	DEFINE_LEVEL(stem, 2)						\
+	DEFINE_LEVEL(stem, 3)						\
+	DEFINE_LEVEL(stem, 4)						\
+	DEFINE_LEVEL(stem, 5)						\
+	DEFINE_LEVEL(stem, 6)						\
+	DEFINE_LEVEL(stem, 7)
+
+static struct btrfs_lockdep_keyset {
+	u64			id;		/* root objectid */
+	/* Longest entry: btrfs-free-space-00 */
+	char			names[BTRFS_MAX_LEVEL][20];
+	struct lock_class_key	keys[BTRFS_MAX_LEVEL];
+} btrfs_lockdep_keysets[] = {
+	{ .id = BTRFS_ROOT_TREE_OBJECTID,	DEFINE_NAME("root")	},
+	{ .id = BTRFS_EXTENT_TREE_OBJECTID,	DEFINE_NAME("extent")	},
+	{ .id = BTRFS_CHUNK_TREE_OBJECTID,	DEFINE_NAME("chunk")	},
+	{ .id = BTRFS_DEV_TREE_OBJECTID,	DEFINE_NAME("dev")	},
+	{ .id = BTRFS_CSUM_TREE_OBJECTID,	DEFINE_NAME("csum")	},
+	{ .id = BTRFS_QUOTA_TREE_OBJECTID,	DEFINE_NAME("quota")	},
+	{ .id = BTRFS_TREE_LOG_OBJECTID,	DEFINE_NAME("log")	},
+	{ .id = BTRFS_TREE_RELOC_OBJECTID,	DEFINE_NAME("treloc")	},
+	{ .id = BTRFS_DATA_RELOC_TREE_OBJECTID,	DEFINE_NAME("dreloc")	},
+	{ .id = BTRFS_UUID_TREE_OBJECTID,	DEFINE_NAME("uuid")	},
+	{ .id = BTRFS_FREE_SPACE_TREE_OBJECTID,	DEFINE_NAME("free-space") },
+	{ .id = 0,				DEFINE_NAME("tree")	},
+};
+
+#undef DEFINE_LEVEL
+#undef DEFINE_NAME
+
+void btrfs_set_buffer_lockdep_class(u64 objectid, struct extent_buffer *eb, int level)
+{
+	struct btrfs_lockdep_keyset *ks;
+
+	BUG_ON(level >= ARRAY_SIZE(ks->keys));
+
+	/* Find the matching keyset, id 0 is the default entry */
+	for (ks = btrfs_lockdep_keysets; ks->id; ks++)
+		if (ks->id == objectid)
+			break;
+
+	lockdep_set_class_and_name(&eb->lock, &ks->keys[level], ks->names[level]);
+}
+
+#endif
+
 /*
  * Extent buffer locking
  * =====================
diff --git a/fs/btrfs/locking.h b/fs/btrfs/locking.h
index a2e1f1f5c6e3..97370ec0cd29 100644
--- a/fs/btrfs/locking.h
+++ b/fs/btrfs/locking.h
@@ -130,4 +130,13 @@ void btrfs_drew_write_unlock(struct btrfs_drew_lock *lock);
 void btrfs_drew_read_lock(struct btrfs_drew_lock *lock);
 void btrfs_drew_read_unlock(struct btrfs_drew_lock *lock);
 
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+void btrfs_set_buffer_lockdep_class(u64 objectid, struct extent_buffer *eb, int level);
+#else
+static inline void btrfs_set_buffer_lockdep_class(u64 objectid,
+					struct extent_buffer *eb, int level)
+{
+}
+#endif
+
 #endif
-- 
2.35.1

[PATCH AUTOSEL 5.15 18/20] btrfs: fix lockdep splat with reloc root extent buffers

[Sasha Levin]

From: Josef Bacik <josef@toxicpanda.com>

[ Upstream commit b40130b23ca4a08c5785d5a3559805916bddba3c ]

We have been hitting the following lockdep splat with btrfs/187 recently

  WARNING: possible circular locking dependency detected
  5.19.0-rc8+ #775 Not tainted
  ------------------------------------------------------
  btrfs/752500 is trying to acquire lock:
  ffff97e1875a97b8 (btrfs-treloc-02#2){+.+.}-{3:3}, at: __btrfs_tree_lock+0x24/0x110

  but task is already holding lock:
  ffff97e1875a9278 (btrfs-tree-01/1){+.+.}-{3:3}, at: __btrfs_tree_lock+0x24/0x110

  which lock already depends on the new lock.

  the existing dependency chain (in reverse order) is:

  -> #2 (btrfs-tree-01/1){+.+.}-{3:3}:
	 down_write_nested+0x41/0x80
	 __btrfs_tree_lock+0x24/0x110
	 btrfs_init_new_buffer+0x7d/0x2c0
	 btrfs_alloc_tree_block+0x120/0x3b0
	 __btrfs_cow_block+0x136/0x600
	 btrfs_cow_block+0x10b/0x230
	 btrfs_search_slot+0x53b/0xb70
	 btrfs_lookup_inode+0x2a/0xa0
	 __btrfs_update_delayed_inode+0x5f/0x280
	 btrfs_async_run_delayed_root+0x24c/0x290
	 btrfs_work_helper+0xf2/0x3e0
	 process_one_work+0x271/0x590
	 worker_thread+0x52/0x3b0
	 kthread+0xf0/0x120
	 ret_from_fork+0x1f/0x30

  -> #1 (btrfs-tree-01){++++}-{3:3}:
	 down_write_nested+0x41/0x80
	 __btrfs_tree_lock+0x24/0x110
	 btrfs_search_slot+0x3c3/0xb70
	 do_relocation+0x10c/0x6b0
	 relocate_tree_blocks+0x317/0x6d0
	 relocate_block_group+0x1f1/0x560
	 btrfs_relocate_block_group+0x23e/0x400
	 btrfs_relocate_chunk+0x4c/0x140
	 btrfs_balance+0x755/0xe40
	 btrfs_ioctl+0x1ea2/0x2c90
	 __x64_sys_ioctl+0x88/0xc0
	 do_syscall_64+0x38/0x90
	 entry_SYSCALL_64_after_hwframe+0x63/0xcd

  -> #0 (btrfs-treloc-02#2){+.+.}-{3:3}:
	 __lock_acquire+0x1122/0x1e10
	 lock_acquire+0xc2/0x2d0
	 down_write_nested+0x41/0x80
	 __btrfs_tree_lock+0x24/0x110
	 btrfs_lock_root_node+0x31/0x50
	 btrfs_search_slot+0x1cb/0xb70
	 replace_path+0x541/0x9f0
	 merge_reloc_root+0x1d6/0x610
	 merge_reloc_roots+0xe2/0x260
	 relocate_block_group+0x2c8/0x560
	 btrfs_relocate_block_group+0x23e/0x400
	 btrfs_relocate_chunk+0x4c/0x140
	 btrfs_balance+0x755/0xe40
	 btrfs_ioctl+0x1ea2/0x2c90
	 __x64_sys_ioctl+0x88/0xc0
	 do_syscall_64+0x38/0x90
	 entry_SYSCALL_64_after_hwframe+0x63/0xcd

  other info that might help us debug this:

  Chain exists of:
    btrfs-treloc-02#2 --> btrfs-tree-01 --> btrfs-tree-01/1

   Possible unsafe locking scenario:

	 CPU0                    CPU1
	 ----                    ----
    lock(btrfs-tree-01/1);
				 lock(btrfs-tree-01);
				 lock(btrfs-tree-01/1);
    lock(btrfs-treloc-02#2);

   *** DEADLOCK ***

  7 locks held by btrfs/752500:
   #0: ffff97e292fdf460 (sb_writers#12){.+.+}-{0:0}, at: btrfs_ioctl+0x208/0x2c90
   #1: ffff97e284c02050 (&fs_info->reclaim_bgs_lock){+.+.}-{3:3}, at: btrfs_balance+0x55f/0xe40
   #2: ffff97e284c00878 (&fs_info->cleaner_mutex){+.+.}-{3:3}, at: btrfs_relocate_block_group+0x236/0x400
   #3: ffff97e292fdf650 (sb_internal#2){.+.+}-{0:0}, at: merge_reloc_root+0xef/0x610
   #4: ffff97e284c02378 (btrfs_trans_num_writers){++++}-{0:0}, at: join_transaction+0x1a8/0x5a0
   #5: ffff97e284c023a0 (btrfs_trans_num_extwriters){++++}-{0:0}, at: join_transaction+0x1a8/0x5a0
   #6: ffff97e1875a9278 (btrfs-tree-01/1){+.+.}-{3:3}, at: __btrfs_tree_lock+0x24/0x110

  stack backtrace:
  CPU: 1 PID: 752500 Comm: btrfs Not tainted 5.19.0-rc8+ #775
  Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.13.0-2.fc32 04/01/2014
  Call Trace:

   dump_stack_lvl+0x56/0x73
   check_noncircular+0xd6/0x100
   ? lock_is_held_type+0xe2/0x140
   __lock_acquire+0x1122/0x1e10
   lock_acquire+0xc2/0x2d0
   ? __btrfs_tree_lock+0x24/0x110
   down_write_nested+0x41/0x80
   ? __btrfs_tree_lock+0x24/0x110
   __btrfs_tree_lock+0x24/0x110
   btrfs_lock_root_node+0x31/0x50
   btrfs_search_slot+0x1cb/0xb70
   ? lock_release+0x137/0x2d0
   ? _raw_spin_unlock+0x29/0x50
   ? release_extent_buffer+0x128/0x180
   replace_path+0x541/0x9f0
   merge_reloc_root+0x1d6/0x610
   merge_reloc_roots+0xe2/0x260
   relocate_block_group+0x2c8/0x560
   btrfs_relocate_block_group+0x23e/0x400
   btrfs_relocate_chunk+0x4c/0x140
   btrfs_balance+0x755/0xe40
   btrfs_ioctl+0x1ea2/0x2c90
   ? lock_is_held_type+0xe2/0x140
   ? lock_is_held_type+0xe2/0x140
   ? __x64_sys_ioctl+0x88/0xc0
   __x64_sys_ioctl+0x88/0xc0
   do_syscall_64+0x38/0x90
   entry_SYSCALL_64_after_hwframe+0x63/0xcd

This isn't necessarily new, it's just tricky to hit in practice.  There
are two competing things going on here.  With relocation we create a
snapshot of every fs tree with a reloc tree.  Any extent buffers that
get initialized here are initialized with the reloc root lockdep key.
However since it is a snapshot, any blocks that are currently in cache
that originally belonged to the fs tree will have the normal tree
lockdep key set.  This creates the lock dependency of

  reloc tree -> normal tree

for the extent buffer locking during the first phase of the relocation
as we walk down the reloc root to relocate blocks.

However this is problematic because the final phase of the relocation is
merging the reloc root into the original fs root.  This involves
searching down to any keys that exist in the original fs root and then
swapping the relocated block and the original fs root block.  We have to
search down to the fs root first, and then go search the reloc root for
the block we need to replace.  This creates the dependency of

  normal tree -> reloc tree

which is why lockdep complains.

Additionally even if we were to fix this particular mismatch with a
different nesting for the merge case, we're still slotting in a block
that has a owner of the reloc root objectid into a normal tree, so that
block will have its lockdep key set to the tree reloc root, and create a
lockdep splat later on when we wander into that block from the fs root.

Unfortunately the only solution here is to make sure we do not set the
lockdep key to the reloc tree lockdep key normally, and then reset any
blocks we wander into from the reloc root when we're doing the merged.

This solves the problem of having mixed tree reloc keys intermixed with
normal tree keys, and then allows us to make sure in the merge case we
maintain the lock order of

  normal tree -> reloc tree

We handle this by setting a bit on the reloc root when we do the search
for the block we want to relocate, and any block we search into or COW
at that point gets set to the reloc tree key.  This works correctly
because we only ever COW down to the parent node, so we aren't resetting
the key for the block we're linking into the fs root.

With this patch we no longer have the lockdep splat in btrfs/187.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/btrfs/ctree.c       |  3 +++
 fs/btrfs/ctree.h       |  2 ++
 fs/btrfs/extent-tree.c | 18 +++++++++++++++++-
 fs/btrfs/extent_io.c   | 11 ++++++++++-
 fs/btrfs/locking.c     | 11 +++++++++++
 fs/btrfs/locking.h     |  5 +++++
 fs/btrfs/relocation.c  |  2 ++
 7 files changed, 50 insertions(+), 2 deletions(-)

diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index 341ce90d24b1..fb7e331b6975 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -1938,6 +1938,9 @@ int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root *root,
 
 		if (!p->skip_locking) {
 			level = btrfs_header_level(b);
+
+			btrfs_maybe_reset_lockdep_class(root, b);
+
 			if (level <= write_lock_level) {
 				btrfs_tree_lock(b);
 				p->locks[level] = BTRFS_WRITE_LOCK;
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index d1838de0b39c..ba402f60c87f 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -1105,6 +1105,8 @@ enum {
 	BTRFS_ROOT_QGROUP_FLUSHING,
 	/* This root has a drop operation that was started previously. */
 	BTRFS_ROOT_UNFINISHED_DROP,
+	/* This reloc root needs to have its buffers lockdep class reset. */
+	BTRFS_ROOT_RESET_LOCKDEP_CLASS,
 };
 
 static inline void btrfs_wake_unfinished_drop(struct btrfs_fs_info *fs_info)
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 248ea15c9734..c71f6480d4d4 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -4781,6 +4781,7 @@ btrfs_init_new_buffer(struct btrfs_trans_handle *trans, struct btrfs_root *root,
 {
 	struct btrfs_fs_info *fs_info = root->fs_info;
 	struct extent_buffer *buf;
+	u64 lockdep_owner = owner;
 
 	buf = btrfs_find_create_tree_block(fs_info, bytenr, owner, level);
 	if (IS_ERR(buf))
@@ -4799,12 +4800,27 @@ btrfs_init_new_buffer(struct btrfs_trans_handle *trans, struct btrfs_root *root,
 		return ERR_PTR(-EUCLEAN);
 	}
 
+	/*
+	 * The reloc trees are just snapshots, so we need them to appear to be
+	 * just like any other fs tree WRT lockdep.
+	 *
+	 * The exception however is in replace_path() in relocation, where we
+	 * hold the lock on the original fs root and then search for the reloc
+	 * root.  At that point we need to make sure any reloc root buffers are
+	 * set to the BTRFS_TREE_RELOC_OBJECTID lockdep class in order to make
+	 * lockdep happy.
+	 */
+	if (lockdep_owner == BTRFS_TREE_RELOC_OBJECTID &&
+	    !test_bit(BTRFS_ROOT_RESET_LOCKDEP_CLASS, &root->state))
+		lockdep_owner = BTRFS_FS_TREE_OBJECTID;
+
 	/*
 	 * This needs to stay, because we could allocate a freed block from an
 	 * old tree into a new tree, so we need to make sure this new block is
 	 * set to the appropriate level and owner.
 	 */
-	btrfs_set_buffer_lockdep_class(owner, buf, level);
+	btrfs_set_buffer_lockdep_class(lockdep_owner, buf, level);
+
 	__btrfs_tree_lock(buf, nest);
 	btrfs_clean_tree_block(buf);
 	clear_bit(EXTENT_BUFFER_STALE, &buf->bflags);
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index a90546b3107c..0346a0d95729 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -6107,6 +6107,7 @@ struct extent_buffer *alloc_extent_buffer(struct btrfs_fs_info *fs_info,
 	struct extent_buffer *exists = NULL;
 	struct page *p;
 	struct address_space *mapping = fs_info->btree_inode->i_mapping;
+	u64 lockdep_owner = owner_root;
 	int uptodate = 1;
 	int ret;
 
@@ -6141,7 +6142,15 @@ struct extent_buffer *alloc_extent_buffer(struct btrfs_fs_info *fs_info,
 	eb = __alloc_extent_buffer(fs_info, start, len);
 	if (!eb)
 		return ERR_PTR(-ENOMEM);
-	btrfs_set_buffer_lockdep_class(owner_root, eb, level);
+
+	/*
+	 * The reloc trees are just snapshots, so we need them to appear to be
+	 * just like any other fs tree WRT lockdep.
+	 */
+	if (lockdep_owner == BTRFS_TREE_RELOC_OBJECTID)
+		lockdep_owner = BTRFS_FS_TREE_OBJECTID;
+
+	btrfs_set_buffer_lockdep_class(lockdep_owner, eb, level);
 
 	num_pages = num_extent_pages(eb);
 	for (i = 0; i < num_pages; i++, index++) {
diff --git a/fs/btrfs/locking.c b/fs/btrfs/locking.c
index 5747c63929df..9063072b399b 100644
--- a/fs/btrfs/locking.c
+++ b/fs/btrfs/locking.c
@@ -91,6 +91,13 @@ void btrfs_set_buffer_lockdep_class(u64 objectid, struct extent_buffer *eb, int
 	lockdep_set_class_and_name(&eb->lock, &ks->keys[level], ks->names[level]);
 }
 
+void btrfs_maybe_reset_lockdep_class(struct btrfs_root *root, struct extent_buffer *eb)
+{
+	if (test_bit(BTRFS_ROOT_RESET_LOCKDEP_CLASS, &root->state))
+		btrfs_set_buffer_lockdep_class(root->root_key.objectid,
+					       eb, btrfs_header_level(eb));
+}
+
 #endif
 
 /*
@@ -244,6 +251,8 @@ struct extent_buffer *btrfs_lock_root_node(struct btrfs_root *root)
 
 	while (1) {
 		eb = btrfs_root_node(root);
+
+		btrfs_maybe_reset_lockdep_class(root, eb);
 		btrfs_tree_lock(eb);
 		if (eb == root->node)
 			break;
@@ -265,6 +274,8 @@ struct extent_buffer *btrfs_read_lock_root_node(struct btrfs_root *root)
 
 	while (1) {
 		eb = btrfs_root_node(root);
+
+		btrfs_maybe_reset_lockdep_class(root, eb);
 		btrfs_tree_read_lock(eb);
 		if (eb == root->node)
 			break;
diff --git a/fs/btrfs/locking.h b/fs/btrfs/locking.h
index 97370ec0cd29..26a2f962c268 100644
--- a/fs/btrfs/locking.h
+++ b/fs/btrfs/locking.h
@@ -132,11 +132,16 @@ void btrfs_drew_read_unlock(struct btrfs_drew_lock *lock);
 
 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 void btrfs_set_buffer_lockdep_class(u64 objectid, struct extent_buffer *eb, int level);
+void btrfs_maybe_reset_lockdep_class(struct btrfs_root *root, struct extent_buffer *eb);
 #else
 static inline void btrfs_set_buffer_lockdep_class(u64 objectid,
 					struct extent_buffer *eb, int level)
 {
 }
+static inline void btrfs_maybe_reset_lockdep_class(struct btrfs_root *root,
+						   struct extent_buffer *eb)
+{
+}
 #endif
 
 #endif
diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
index 429a198f8937..689176c5f748 100644
--- a/fs/btrfs/relocation.c
+++ b/fs/btrfs/relocation.c
@@ -1326,7 +1326,9 @@ int replace_path(struct btrfs_trans_handle *trans, struct reloc_control *rc,
 		btrfs_release_path(path);
 
 		path->lowest_level = level;
+		set_bit(BTRFS_ROOT_RESET_LOCKDEP_CLASS, &src->state);
 		ret = btrfs_search_slot(trans, src, &key, path, 0, 1);
+		clear_bit(BTRFS_ROOT_RESET_LOCKDEP_CLASS, &src->state);
 		path->lowest_level = 0;
 		if (ret) {
 			if (ret > 0)
-- 
2.35.1

[PATCH AUTOSEL 5.15 19/20] btrfs: tree-checker: check for overlapping extent items

[Sasha Levin]

From: Josef Bacik <josef@toxicpanda.com>

[ Upstream commit 899b7f69f244e539ea5df1b4d756046337de44a5 ]

We're seeing a weird problem in production where we have overlapping
extent items in the extent tree.  It's unclear where these are coming
from, and in debugging we realized there's no check in the tree checker
for this sort of problem.  Add a check to the tree-checker to make sure
that the extents do not overlap each other.

Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/btrfs/tree-checker.c | 25 +++++++++++++++++++++++--
 1 file changed, 23 insertions(+), 2 deletions(-)

diff --git a/fs/btrfs/tree-checker.c b/fs/btrfs/tree-checker.c
index 51382d2be3d4..a84d2d489510 100644
--- a/fs/btrfs/tree-checker.c
+++ b/fs/btrfs/tree-checker.c
@@ -1216,7 +1216,8 @@ static void extent_err(const struct extent_buffer *eb, int slot,
 }
 
 static int check_extent_item(struct extent_buffer *leaf,
-			     struct btrfs_key *key, int slot)
+			     struct btrfs_key *key, int slot,
+			     struct btrfs_key *prev_key)
 {
 	struct btrfs_fs_info *fs_info = leaf->fs_info;
 	struct btrfs_extent_item *ei;
@@ -1436,6 +1437,26 @@ static int check_extent_item(struct extent_buffer *leaf,
 			   total_refs, inline_refs);
 		return -EUCLEAN;
 	}
+
+	if ((prev_key->type == BTRFS_EXTENT_ITEM_KEY) ||
+	    (prev_key->type == BTRFS_METADATA_ITEM_KEY)) {
+		u64 prev_end = prev_key->objectid;
+
+		if (prev_key->type == BTRFS_METADATA_ITEM_KEY)
+			prev_end += fs_info->nodesize;
+		else
+			prev_end += prev_key->offset;
+
+		if (unlikely(prev_end > key->objectid)) {
+			extent_err(leaf, slot,
+	"previous extent [%llu %u %llu] overlaps current extent [%llu %u %llu]",
+				   prev_key->objectid, prev_key->type,
+				   prev_key->offset, key->objectid, key->type,
+				   key->offset);
+			return -EUCLEAN;
+		}
+	}
+
 	return 0;
 }
 
@@ -1604,7 +1625,7 @@ static int check_leaf_item(struct extent_buffer *leaf,
 		break;
 	case BTRFS_EXTENT_ITEM_KEY:
 	case BTRFS_METADATA_ITEM_KEY:
-		ret = check_extent_item(leaf, key, slot);
+		ret = check_extent_item(leaf, key, slot, prev_key);
 		break;
 	case BTRFS_TREE_BLOCK_REF_KEY:
 	case BTRFS_SHARED_DATA_REF_KEY:
-- 
2.35.1