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[v8,35/39] btrfs: do not panic in __add_reloc_root

Message ID a337ff56171781425fcadc9ac17c8c14203e6589.1615580595.git.josef@toxicpanda.com (mailing list archive)
State New, archived
Headers show
Series Cleanup error handling in relocation | expand

Commit Message

Josef Bacik March 12, 2021, 8:25 p.m. UTC
If we have a duplicate entry for a reloc root then we could have fs
corruption that resulted in a double allocation.  Since this shouldn't
happen unless there is corruption, add an ASSERT(ret != -EEXIST) to all
of the callers of __add_reloc_root() to catch any logic mistakes for
developers, otherwise normal error handling will happen for normal
users.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
---
 fs/btrfs/relocation.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)
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Patch

diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
index 2fc04f96294e..857da684d415 100644
--- a/fs/btrfs/relocation.c
+++ b/fs/btrfs/relocation.c
@@ -638,9 +638,10 @@  static int __must_check __add_reloc_root(struct btrfs_root *root)
 				   node->bytenr, &node->rb_node);
 	spin_unlock(&rc->reloc_root_tree.lock);
 	if (rb_node) {
-		btrfs_panic(fs_info, -EEXIST,
+		btrfs_err(fs_info,
 			    "Duplicate root found for start=%llu while inserting into relocation tree",
 			    node->bytenr);
+		return -EEXIST;
 	}
 
 	list_add_tail(&root->root_list, &rc->reloc_roots);
@@ -882,6 +883,7 @@  int btrfs_init_reloc_root(struct btrfs_trans_handle *trans,
 		return PTR_ERR(reloc_root);
 
 	ret = __add_reloc_root(reloc_root);
+	ASSERT(ret != -EEXIST);
 	if (ret) {
 		btrfs_put_root(reloc_root);
 		return ret;
@@ -4054,6 +4056,7 @@  int btrfs_recover_relocation(struct btrfs_root *root)
 		}
 
 		err = __add_reloc_root(reloc_root);
+		ASSERT(err != -EEXIST);
 		if (err) {
 			list_add_tail(&reloc_root->root_list, &reloc_roots);
 			btrfs_put_root(fs_root);
@@ -4274,6 +4277,7 @@  int btrfs_reloc_post_snapshot(struct btrfs_trans_handle *trans,
 		return PTR_ERR(reloc_root);
 
 	ret = __add_reloc_root(reloc_root);
+	ASSERT(ret != -EEXIST);
 	if (ret) {
 		btrfs_put_root(reloc_root);
 		return ret;