diff options
Diffstat (limited to 'fs/btrfs/qgroup.c')
| -rw-r--r-- | fs/btrfs/qgroup.c | 38 |
1 files changed, 30 insertions, 8 deletions
diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c index 07ec06d4e972..0fa121171ca1 100644 --- a/fs/btrfs/qgroup.c +++ b/fs/btrfs/qgroup.c @@ -1704,17 +1704,39 @@ int btrfs_qgroup_trace_extent_nolock(struct btrfs_fs_info *fs_info, return 0; } -int btrfs_qgroup_trace_extent_post(struct btrfs_fs_info *fs_info, +int btrfs_qgroup_trace_extent_post(struct btrfs_trans_handle *trans, struct btrfs_qgroup_extent_record *qrecord) { struct ulist *old_root; u64 bytenr = qrecord->bytenr; int ret; - ret = btrfs_find_all_roots(NULL, fs_info, bytenr, 0, &old_root, false); + /* + * We are always called in a context where we are already holding a + * transaction handle. Often we are called when adding a data delayed + * reference from btrfs_truncate_inode_items() (truncating or unlinking), + * in which case we will be holding a write lock on extent buffer from a + * subvolume tree. In this case we can't allow btrfs_find_all_roots() to + * acquire fs_info->commit_root_sem, because that is a higher level lock + * that must be acquired before locking any extent buffers. + * + * So we want btrfs_find_all_roots() to not acquire the commit_root_sem + * but we can't pass it a non-NULL transaction handle, because otherwise + * it would not use commit roots and would lock extent buffers, causing + * a deadlock if it ends up trying to read lock the same extent buffer + * that was previously write locked at btrfs_truncate_inode_items(). + * + * So pass a NULL transaction handle to btrfs_find_all_roots() and + * explicitly tell it to not acquire the commit_root_sem - if we are + * holding a transaction handle we don't need its protection. + */ + ASSERT(trans != NULL); + + ret = btrfs_find_all_roots(NULL, trans->fs_info, bytenr, 0, &old_root, + false, true); if (ret < 0) { - fs_info->qgroup_flags |= BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT; - btrfs_warn(fs_info, + trans->fs_info->qgroup_flags |= BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT; + btrfs_warn(trans->fs_info, "error accounting new delayed refs extent (err code: %d), quota inconsistent", ret); return 0; @@ -1758,7 +1780,7 @@ int btrfs_qgroup_trace_extent(struct btrfs_trans_handle *trans, u64 bytenr, kfree(record); return 0; } - return btrfs_qgroup_trace_extent_post(fs_info, record); + return btrfs_qgroup_trace_extent_post(trans, record); } int btrfs_qgroup_trace_leaf_items(struct btrfs_trans_handle *trans, @@ -2629,7 +2651,7 @@ int btrfs_qgroup_account_extents(struct btrfs_trans_handle *trans) /* Search commit root to find old_roots */ ret = btrfs_find_all_roots(NULL, fs_info, record->bytenr, 0, - &record->old_roots, false); + &record->old_roots, false, false); if (ret < 0) goto cleanup; } @@ -2645,7 +2667,7 @@ int btrfs_qgroup_account_extents(struct btrfs_trans_handle *trans) * current root. It's safe inside commit_transaction(). */ ret = btrfs_find_all_roots(trans, fs_info, - record->bytenr, BTRFS_SEQ_LAST, &new_roots, false); + record->bytenr, BTRFS_SEQ_LAST, &new_roots, false, false); if (ret < 0) goto cleanup; if (qgroup_to_skip) { @@ -3179,7 +3201,7 @@ static int qgroup_rescan_leaf(struct btrfs_trans_handle *trans, num_bytes = found.offset; ret = btrfs_find_all_roots(NULL, fs_info, found.objectid, 0, - &roots, false); + &roots, false, false); if (ret < 0) goto out; /* For rescan, just pass old_roots as NULL */ |