On 03/15/2018 09:15 AM, Misono, Tomohiro wrote:
> Allow normal user to call "subvolume list/show" by using 3 new
> unprivileged ioctls (BTRFS_IOC_GET_SUBVOL_INFO,
> BTRFS_IOC_GET_SUBVOL_ROOTREF and BTRFS_IOC_INO_LOOKUP_USER).
>
> Note that for root, "subvolume list" returns all the subvolume in the
> filesystem by default, but for normal user, it returns subvolumes
> which exist under the specified path (including the path itself).
I found the original "btrfs sub list" behavior quite confusing. I think that
the problem is that the output is too technical. And the '-a' switch increase
this confusion. May be that I am no smart enough :(
The "normal user behavior" seems to me more coherent. However I am not sure
that this differences should be acceptable. In any case it should be tracked in
the man page.
Time to add another command (something like "btrfs sub ls") with a more "human
friendly" output ?
> The specified path itself is not needed to be a subvolume.
> If the subvolume cannot be opened but the parent directory can be,
> the information other than name or id would be zeroed out.
>
> Also, for normal user, snapshot filed of "subvolume show" just lists
> the snapshots under the specified subvolume.
>
> Signed-off-by: Tomohiro Misono <misono.tomoh...@jp.fujitsu.com>
> ---
> btrfs-list.c | 326
> +++++++++++++++++++++++++++++++++++++++++++++++++++++--
> cmds-subvolume.c | 13 +++
> 2 files changed, 332 insertions(+), 7 deletions(-)
>
[....]
> static void print_subvolume_column(struct root_info *subv,
> enum btrfs_list_column_enum column)
> {
> @@ -1527,17 +1826,28 @@ static int btrfs_list_subvols(int fd, struct
> root_lookup *root_lookup,
> {
> int ret;
>
> - ret = list_subvol_search(fd, root_lookup);
> - if (ret) {
> - error("can't perform the search: %m");
> - return ret;
> + ret = check_perm_for_tree_search(fd);
> + if (ret < 0) {
> + error("can't check the permission for tree search: %s",
> + strerror(-ret));
> + return -1;
> }
>
> /*
> * now we have an rbtree full of root_info objects, but we need to fill
> * in their path names within the subvol that is referencing each one.
> */
> - ret = list_subvol_fill_paths(fd, root_lookup);
> + if (ret) {
> + ret = list_subvol_search(fd, root_lookup);
> + if (ret) {
> + error("can't perform the search: %s", strerror(-ret));
> + return ret;
> + }
> + ret = list_subvol_fill_paths(fd, root_lookup);
> + } else {
> + ret = list_subvol_user(fd, root_lookup, path);
> + }
> +
> return ret;
I think that the check above should be refined: if I run "btrfs sub list"
patched in a kernel without patch I don't get any error and/or warning:
ghigo@venice:~/btrfs/btrfs-progs$ # kernel w/o patch; btrfs-progs w/patch
ghigo@venice:~/btrfs/btrfs-progs$ ./btrfs sub list /
ghigo@venice:~/btrfs/btrfs-progs$ # kernel w/o patch; btrfs-progs w/o patch
ghigo@venice:~/btrfs/btrfs-progs$ btrfs sub list /
ERROR: can't perform the search: Operation not permitted
I think that in both case an error should be raised
> }
>
> @@ -1631,12 +1941,14 @@ int btrfs_get_subvol(int fd, struct root_info
> *the_ri, const char *path)
> return ret;
> }
>
> + ret = -ENOENT;
> rbn = rb_first(&rl.root);
> while(rbn) {
> ri = rb_entry(rbn, struct root_info, rb_node);
> rr = resolve_root(&rl, ri, root_id);
> - if (rr == -ENOENT) {
> - ret = -ENOENT;
> + if (rr == -ENOENT ||
> + ri->root_id == BTRFS_FS_TREE_OBJECTID ||
> + uuid_is_null(ri->uuid)) {
> rbn = rb_next(rbn);
> continue;
> }
> diff --git a/cmds-subvolume.c b/cmds-subvolume.c
> index faa10c5a..7a7c6f3b 100644
> --- a/cmds-subvolume.c
> +++ b/cmds-subvolume.c
> @@ -596,6 +596,19 @@ static int cmd_subvol_list(int argc, char **argv)
> goto out;
> }
>
> + ret = check_perm_for_tree_search(fd);
> + if (ret < 0) {
> + ret = -1;
> + error("can't check the permission for tree search: %s",
> + strerror(-ret));
> + goto out;
> + }
> + if (!ret && is_list_all) {
> + ret = -1;
> + error("only root can use -a option");
> + goto out;
> + }
> +
> if (flags)
> btrfs_list_setup_filter(&filter_set, BTRFS_LIST_FILTER_FLAGS,
> flags);
>
--
gpg @keyserver.linux.it: Goffredo Baroncelli <kreijackATinwind.it>
Key fingerprint BBF5 1610 0B64 DAC6 5F7D 17B2 0EDA 9B37 8B82 E0B5
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