From 480cde1b22831febacc2a8ab91dfe99d2e5be8e9 Mon Sep 17 00:00:00 2001 From: Juergen Borleis Date: Tue, 15 Aug 2017 15:46:31 +0200 Subject: state: keep backward compatibility Previous 'state' variable set variants do not know and use metadata. The 'direct' storage backend's read function honors this, but not its counterpart the write function. This makes an update of the 'state' variable set impossible. This change makes backward compatibility explicit, else it complains in the read function as well. With some more debug output it helps the developer to do things right. Signed-off-by: Juergen Borleis Signed-off-by: Sascha Hauer --- common/state/backend_bucket_direct.c | 28 +++++++++++++++++++--------- 1 file changed, 19 insertions(+), 9 deletions(-) (limited to 'common/state') diff --git a/common/state/backend_bucket_direct.c b/common/state/backend_bucket_direct.c index 4465ed0e41..958696ed94 100644 --- a/common/state/backend_bucket_direct.c +++ b/common/state/backend_bucket_direct.c @@ -69,6 +69,11 @@ static int state_backend_bucket_direct_read(struct state_backend_storage_bucket if (meta.magic == direct_magic) { read_len = meta.written_length; } else { + if (!IS_ENABLED(CONFIG_STATE_BACKWARD_COMPATIBLE)) { + dev_err(direct->dev, "No meta data header found\n"); + dev_dbg(direct->dev, "Enable backward compatibility or increase stride size\n"); + return -EINVAL; + } read_len = direct->max_size; ret = lseek(direct->fd, direct->offset, SEEK_SET); if (ret < 0) { @@ -103,21 +108,26 @@ static int state_backend_bucket_direct_write(struct state_backend_storage_bucket int ret; struct state_backend_storage_bucket_direct_meta meta; - if (len > direct->max_size - sizeof(meta)) - return -E2BIG; - ret = lseek(direct->fd, direct->offset, SEEK_SET); if (ret < 0) { dev_err(direct->dev, "Failed to seek file, %d\n", ret); return ret; } - meta.magic = direct_magic; - meta.written_length = len; - ret = write_full(direct->fd, &meta, sizeof(meta)); - if (ret < 0) { - dev_err(direct->dev, "Failed to write metadata to file, %d\n", ret); - return ret; + /* write the meta data only if there is head room */ + if (len <= direct->max_size - sizeof(meta)) { + meta.magic = direct_magic; + meta.written_length = len; + ret = write_full(direct->fd, &meta, sizeof(meta)); + if (ret < 0) { + dev_err(direct->dev, "Failed to write metadata to file, %d\n", ret); + return ret; + } + } else { + if (!IS_ENABLED(CONFIG_STATE_BACKWARD_COMPATIBLE)) { + dev_dbg(direct->dev, "Too small stride size: must skip metadata! Increase stride size\n"); + return -EINVAL; + } } ret = write_full(direct->fd, buf, len); -- cgit v1.2.3