| Message ID | 20250118-vfs-mount-bc855e2c7463@brauner (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | [GIT,PULL] vfs mount | expand |
On Sat, Jan 18, 2025 at 02:06:58PM +0100, Christian Brauner wrote:
> samples: add a mountinfo program to demonstrate statmount()/listmount()
Hi Jeff, Christian,
LKFT has caught a build error with the above commit:
/builds/linux/samples/vfs/mountinfo.c:235:18: error: 'SYS_pidfd_open' undeclared (first use in this function); did you mean 'SYS_mq_open'?
pidfd = syscall(SYS_pidfd_open, pid, 0);
^~~~~~~~~~~~~~
SYS_mq_open
The full log is here: https://qa-reports.linaro.org/lkft/sashal-linus-next/build/v6.13-rc7-511-g109a8e0fa9d6/testrun/26809210/suite/build/test/gcc-8-allyesconfig/log
On Sun, Jan 19, 2025 at 07:10:57PM -0500, Sasha Levin wrote: > On Sat, Jan 18, 2025 at 02:06:58PM +0100, Christian Brauner wrote: > > samples: add a mountinfo program to demonstrate statmount()/listmount() > > Hi Jeff, Christian, > > LKFT has caught a build error with the above commit: > > /builds/linux/samples/vfs/mountinfo.c:235:18: error: 'SYS_pidfd_open' undeclared (first use in this function); did you mean 'SYS_mq_open'? > pidfd = syscall(SYS_pidfd_open, pid, 0); > ^~~~~~~~~~~~~~ > SYS_mq_open > > The full log is here: https://qa-reports.linaro.org/lkft/sashal-linus-next/build/v6.13-rc7-511-g109a8e0fa9d6/testrun/26809210/suite/build/test/gcc-8-allyesconfig/log Thanks for the report. This is a build failure in userspace sample code. I have pushed a fix and generated a new tag which I will send out shortly. Christian
The pull request you sent on Sat, 18 Jan 2025 14:06:58 +0100:
> git@gitolite.kernel.org:pub/scm/linux/kernel/git/vfs/vfs tags/vfs-6.14-rc1.mount
has been merged into torvalds/linux.git:
https://git.kernel.org/torvalds/c/f9d94f78a8749e15de8aeb2e281898aa980e62d9
Thank you!
diff --cc fs/namespace.c index 64deda6f5b2c,371c860f49de..000000000000 --- a/fs/namespace.c
Hey Linus, /* Summary */ This contains mount update for this cycle: - Add a mountinfo program to demonstrate statmount()/listmount() Add a new "mountinfo" sample userland program that demonstrates how to use statmount() and listmount() to get at the same info that /proc/pid/mountinfo provides. - Remove pointless nospec.h include. - Prepend statmount.mnt_opts string with security_sb_mnt_opts() Currently these mount options aren't accessible via statmount(). - Add new mount namespaces to mount namespace rbtree outside of the namespace semaphore. - Lockless mount namespace lookup Currently we take the read lock when looking for a mount namespace to list mounts in. We can make this lockless. The simple search case can just use a sequence counter to detect concurrent changes to the rbtree. For walking the list of mount namespaces sequentially via nsfs we keep a separate rcu list as rb_prev() and rb_next() aren't usable safely with rcu. Currently there is no primitive for retrieving the previous list member. To do this we need a new deletion primitive that doesn't poison the prev pointer and a corresponding retrieval helper. Since creating mount namespaces is a relatively rare event compared with querying mounts in a foreign mount namespace this is worth it. Once libmount and systemd pick up this mechanism to list mounts in foreign mount namespaces this will be used very frequently. - Add extended selftests for lockless mount namespace iteration. - Add a sample program to list all mounts on the system, i.e., in all mount namespaces. - Improve mount namespace iteration performance Make finding the last or first mount to start iterating the mount namespace from an O(1) operation and add selftests for iterating the mount table starting from the first and last mount. - Use an xarray for the old mount id While the ida does use the xarray internally we can use it explicitly which allows us to increment the unique mount id under the xa lock. This allows us to remove the atomic as we're now allocating both ids in one go. /* Testing */ gcc version 14.2.0 (Debian 14.2.0-6) Debian clang version 16.0.6 (27+b1) No build failures or warnings were observed. /* Conflicts */ Merge conflicts with mainline ============================= No known conflicts. Merge conflicts with other trees ================================ This will have a merge conflict with vfs-6.14.mount pull request sent in https://lore.kernel.org/r/20250118-vfs-pidfs-5921bfa5632a@brauner and it can be resolved as follows: +++ b/fs/namespace.c @@@ -32,8 -32,6 +32,7 @@@ #include <linux/fs_context.h> #include <linux/shmem_fs.h> #include <linux/mnt_idmapping.h> +#include <linux/pidfs.h> - #include <linux/nospec.h> #include "pnode.h" #include "internal.h" The following changes since commit 344bac8f0d73fe970cd9f5b2f132906317d29e8b: fs: kill MNT_ONRB (2025-01-09 16:58:50 +0100) are available in the Git repository at: git@gitolite.kernel.org:pub/scm/linux/kernel/git/vfs/vfs tags/vfs-6.14-rc1.mount for you to fetch changes up to f79e6eb84d4d2bff99e3ca6c1f140b2af827e904: samples/vfs/mountinfo: Use __u64 instead of uint64_t (2025-01-10 12:08:27 +0100) Please consider pulling these changes from the signed vfs-6.14-rc1.mount tag. Thanks! Christian ---------------------------------------------------------------- vfs-6.14-rc1.mount ---------------------------------------------------------------- Christian Brauner (17): mount: remove inlude/nospec.h include fs: add mount namespace to rbtree late Merge patch series "fs: listmount()/statmount() fix and sample program" fs: lockless mntns rbtree lookup rculist: add list_bidir_{del,prev}_rcu() fs: lockless mntns lookup for nsfs fs: simplify rwlock to spinlock seltests: move nsfs into filesystems subfolder selftests: add tests for mntns iteration selftests: remove unneeded include samples: add test-list-all-mounts Merge patch series "fs: lockless mntns lookup" fs: cache first and last mount selftests: add listmount() iteration tests Merge patch series "fs: tweak mntns iteration" fs: use xarray for old mount id fs: remove useless lockdep assertion Geert Uytterhoeven (1): samples/vfs/mountinfo: Use __u64 instead of uint64_t Jeff Layton (2): samples: add a mountinfo program to demonstrate statmount()/listmount() fs: prepend statmount.mnt_opts string with security_sb_mnt_opts() fs/mount.h | 31 ++- fs/namespace.c | 200 +++++++++------ fs/nsfs.c | 5 +- include/linux/rculist.h | 44 ++++ samples/vfs/.gitignore | 2 + samples/vfs/Makefile | 2 +- samples/vfs/mountinfo.c | 273 +++++++++++++++++++++ samples/vfs/test-list-all-mounts.c | 235 ++++++++++++++++++ .../selftests/{ => filesystems}/nsfs/.gitignore | 1 + .../selftests/{ => filesystems}/nsfs/Makefile | 4 +- .../selftests/{ => filesystems}/nsfs/config | 0 .../selftests/filesystems/nsfs/iterate_mntns.c | 149 +++++++++++ .../selftests/{ => filesystems}/nsfs/owner.c | 0 .../selftests/{ => filesystems}/nsfs/pidns.c | 0 .../selftests/filesystems/statmount/Makefile | 2 +- .../filesystems/statmount/listmount_test.c | 66 +++++ tools/testing/selftests/pidfd/pidfd.h | 1 - 17 files changed, 918 insertions(+), 97 deletions(-) create mode 100644 samples/vfs/mountinfo.c create mode 100644 samples/vfs/test-list-all-mounts.c rename tools/testing/selftests/{ => filesystems}/nsfs/.gitignore (78%) rename tools/testing/selftests/{ => filesystems}/nsfs/Makefile (50%) rename tools/testing/selftests/{ => filesystems}/nsfs/config (100%) create mode 100644 tools/testing/selftests/filesystems/nsfs/iterate_mntns.c rename tools/testing/selftests/{ => filesystems}/nsfs/owner.c (100%) rename tools/testing/selftests/{ => filesystems}/nsfs/pidns.c (100%) create mode 100644 tools/testing/selftests/filesystems/statmount/listmount_test.c