Hello,
This is basically the resend of
"[PATCH v2 00/20] btrfs-progs: Rework of "subvolume list/show" and relax the
root privileges of them" [1]
which I submitted in June. The aim of this series is to allow non-privileged
user
to use basic subvolume functionality (create/list/snapshot/delete; this allows
"list")
They were once in devel branch with some whitespace/comment modification by
david.
I rebased them to current devel branch.
github: https://github.com/t-msn/btrfs-progs/tree/rework-sub-list
Basic logic/code is the same as before. Some differences are:
- Use latest libbtrfsutil from Omar [2] (thus drop first part of patches).
As a result, "sub list" cannot accept an ordinary directry to be
specified (which is allowed in previous version)
- Drop patches which add new options to "sub list"
- Use 'nobody' as non-privileged test user just like libbtrfsutil test
- Update comments
Importantly, in order to make output consistent for both root and non-privileged
user, this changes the behavior of "subvolume list":
- (default) Only list in subvolume under the specified path.
Path needs to be a subvolume.
- (-a) filter is dropped. i.e. its output is the same as the
default behavior of "sub list" in progs <= 4.19
Therefore, existent scripts may need to update to add -a option
(I believe nobody uses current -a option).
If anyone thinks this is not good, please let me know.
Behavior summary from cover letter in [1]
====
* Behavior summary of new "sub list"
- default (no option)
- lists subvolumes below the specified path (inc. path itself)
- If new ioctls exists non-privileged user can call it
(subvolumes to which the user cannot access will be skipped)
- -a
- updated to remove filter. i.e. the output is the same as current progs
without option (require root privileges)
[Example]
$ mkfs.btrfs -f $DEV
$ mkfs.btrfs -f $DEV2
$ mount $DEV $MNT
$ btrfs subvolume create $MNT/AAA
$ btrfs subvolume create $MNT/BBB
$ btrfs subvolume create $MNT/CCC
$ btrfs subvolume create $MNT/DDD
$ mkdir $MNT/AAA/bbb
$ mkdir $MNT/AAA/ccc
$ mkdir $MNT/AAA/other
$ umount $MNT
$ mount -o subvol=AAA $DEV $MNT
$ mount -o subvol=BBB $DEV $MNT/bbb
$ mount -o subvol=CCC $DEV $MNT/ccc
$ mount -o $DEV2 $MNT/other
$ btrfs subvolume list $MNT # print subvolumes below the path
ID 256 gen 10 top level 5 path .
$ btrfs subvolume list -a $MNT
# print all subvolumes in the fs. the same output as progs<=4.19 without
option
ID 256 gen 10 top level 5 path AAA
ID 258 gen 7 top level 5 path BBB
ID 259 gen 8 top level 5 path CCC
ID 260 gen 9 top level 5 path DDD
* Behavior summary of new "sub show"
- No change for root's output
- If new ioctls exists, non-privileged user can call it
- In that case, path to be shown is absolute path
(for root, it is relative to top-level subvolume)
Also, snapshots to be shown are to which the user can access from current
mount point.
(for root, all snapshots in the fs)
===
[1]
https://lore.kernel.org/linux-btrfs/cover.1529310485.git.misono.tomoh...@jp.fujitsu.com/
[2] https://lore.kernel.org/linux-btrfs/cover.1542181521.git.osan...@fb.com/
Thanks,
Misono
Misono Tomohiro (8):
btrfs-progs: sub list: Use libbtrfsuitl for subvolume list
btrfs-progs: sub list: factor out main part of btrfs_list_subvols
btrfs-progs: sub list: Change the default behavior of "subvolume list"
and allow non-privileged user to call it
btrfs-progs: sub list: Update -a option and remove meaningless filter
btrfs-progs: utils: Fallback to open without O_NOATIME flag in
find_mount_root():
btrfs-progs: sub show: Allow non-privileged user to call "subvolume
show"
btrfs-progs: test: Add helper function to check if test user exists
btrfs-porgs: test: Add cli-test/009 to check subvolume list for both
root and normal user
Documentation/btrfs-subvolume.asciidoc | 25 +-
cmds-subvolume.c | 1149 +++++++++++++++++++-
tests/cli-tests/009-subvolume-list/test.sh | 130 +++
tests/common | 10 +
utils.c | 3 +
5 files changed, 1266 insertions(+), 51 deletions(-)
create mode 100755 tests/cli-tests/009-subvolume-list/test.sh
--
2.19.1
