From 610cb4fb8c6e8c354d3796e98932e79d45d057a4 Mon Sep 17 00:00:00 2001 From: Matthew Ahrens Date: Thu, 6 May 2021 11:24:56 -0700 Subject: undocumented libzfs API changes broke "zfs list" While OpenZFS does permit breaking changes to the libzfs API, we should avoid these changes when reasonably possible, and take steps to mitigate the impact to consumers when changes are necessary. Commit e4288a8397bb1f made a libzfs API change that is especially difficult for consumers because there is no change to the function signatures, only to their behavior. Therefore, consumers can't notice that there was a change at compile time. Also, the API change was incompletely and incorrectly documented. The commit message mentions `zfs_get_prop()` [sic], but all callers of `get_numeric_property()` are impacted: `zfs_prop_get()`, `zfs_prop_get_numeric()`, and `zfs_prop_get_int()`. `zfs_prop_get_int()` always calls `get_numeric_property(src=NULL)`, so it assumes that the filesystem is not mounted. This means that e.g. `zfs_prop_get_int(ZFS_PROP_MOUNTED)` always returns 0. The documentation says that to preserve the previous behavior, callers should initialize `*src=ZPROP_SRC_NONE`, and some callers were changed to do that. However, the existing behavior is actually preserved by initializing `*src=ZPROP_SRC_ALL`, not `NONE`. The code comment above `zfs_prop_get()` says, "src: ... NULL will be treated as ZPROP_SRC_ALL.". However, the code actually treats NULL as ZPROP_SRC_NONE. i.e. `zfs_prop_get(src=NULL)` assumes that the filesystem is not mounted. There are several existing calls which use `src=NULL` which are impacted by the API change, most noticeably those used by `zfs list`, which now assumes that filesystems are not mounted. For example, `zfs list -o name,mounted` previously indicated whether a filesystem was mounted or not, but now it always (incorrectly) indicates that the filesystem is not mounted (`MOUNTED: no`). Similarly, properties that are set at mount time are ignored. E.g. `zfs list -o name,atime` may display an incorrect value if it was set at mount time. To address these problems, this commit reverts commit e4288a8397bb1f: "zfs get: don't lookup mount options when using "-s local"" Reviewed-by: Brian Behlendorf Signed-off-by: Matthew Ahrens Closes #11999 --- cmd/zfs/zfs_main.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'cmd/zfs') diff --git a/cmd/zfs/zfs_main.c b/cmd/zfs/zfs_main.c index 9859a866f..24ff074c4 100644 --- a/cmd/zfs/zfs_main.c +++ b/cmd/zfs/zfs_main.c @@ -1882,6 +1882,7 @@ get_callback(zfs_handle_t *zhp, void *data) { char buf[ZFS_MAXPROPLEN]; char rbuf[ZFS_MAXPROPLEN]; + zprop_source_t sourcetype; char source[ZFS_MAX_DATASET_NAME_LEN]; zprop_get_cbdata_t *cbp = data; nvlist_t *user_props = zfs_get_user_props(zhp); @@ -1892,7 +1893,6 @@ get_callback(zfs_handle_t *zhp, void *data) boolean_t received = is_recvd_column(cbp); for (; pl != NULL; pl = pl->pl_next) { - zprop_source_t sourcetype = cbp->cb_sources; char *recvdval = NULL; /* * Skip the special fake placeholder. This will also skip over @@ -4660,7 +4660,7 @@ zfs_do_send(int argc, char **argv) */ if (fromname && (cp = strchr(fromname, '@')) != NULL) { char origin[ZFS_MAX_DATASET_NAME_LEN]; - zprop_source_t src = ZPROP_SRC_NONE; + zprop_source_t src; (void) zfs_prop_get(zhp, ZFS_PROP_ORIGIN, origin, sizeof (origin), &src, NULL, 0, B_FALSE); -- cgit v1.2.3