From: Josef Bacik josef@toxicpanda.com
[ Upstream commit 4f4317c13a40194940acf4a71670179c4faca2b5 ]
While doing error injection I would sometimes get a corrupt file system. This is because I was injecting errors at btrfs_search_slot, but would only do it one time per stack. This uncovered a problem in commit_fs_roots, where if we get an error we would just break. However we're in a nested loop, the first loop being a loop to find all the dirty fs roots, and then subsequent root updates would succeed clearing the error value.
This isn't likely to happen in real scenarios, however we could potentially get a random ENOMEM once and then not again, and we'd end up with a corrupted file system. Fix this by moving the error checking around a bit to the main loop, as this is the only place where something will fail, and return the error as soon as it occurs.
With this patch my reproducer no longer corrupts the file system.
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/transaction.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-)
diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c index c346ee7ec18d..aca6c467d776 100644 --- a/fs/btrfs/transaction.c +++ b/fs/btrfs/transaction.c @@ -1212,7 +1212,6 @@ static noinline int commit_fs_roots(struct btrfs_trans_handle *trans) struct btrfs_root *gang[8]; int i; int ret; - int err = 0;
spin_lock(&fs_info->fs_roots_radix_lock); while (1) { @@ -1224,6 +1223,8 @@ static noinline int commit_fs_roots(struct btrfs_trans_handle *trans) break; for (i = 0; i < ret; i++) { struct btrfs_root *root = gang[i]; + int ret2; + radix_tree_tag_clear(&fs_info->fs_roots_radix, (unsigned long)root->root_key.objectid, BTRFS_ROOT_TRANS_TAG); @@ -1245,17 +1246,17 @@ static noinline int commit_fs_roots(struct btrfs_trans_handle *trans) root->node); }
- err = btrfs_update_root(trans, fs_info->tree_root, + ret2 = btrfs_update_root(trans, fs_info->tree_root, &root->root_key, &root->root_item); + if (ret2) + return ret2; spin_lock(&fs_info->fs_roots_radix_lock); - if (err) - break; btrfs_qgroup_free_meta_all_pertrans(root); } } spin_unlock(&fs_info->fs_roots_radix_lock); - return err; + return 0; }
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