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btrfs: do not panic in __add_reloc_root 

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>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
Josef Bacik 2021-03-12 15:25:30 -05:00 committed by David Sterba
parent 3c9258632c
commit 57a304cfd4
1 changed files with 5 additions and 1 deletions
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6
fs/btrfs/relocation.c
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@ -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) {
/* Pairs with create_reloc_root */
btrfs_put_root(reloc_root);
@ -4059,6 +4061,7 @@ 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);
@ -4279,6 +4282,7 @@ 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) {
/* Pairs with create_reloc_root */
btrfs_put_root(reloc_root);