Pull vfs superblock updates from Christian Brauner: - Make it possible to share a block device between multiple filesystems. erofs can mount read-only blob devices shared between many superblocks, but because we only tracked a single superblock a freeze, thaw, removal or sync on such a device was never propagated to all the superblocks using it, and there was no way to find them. Add an efficient table to lookup all superblocks using a given block device. - A bunch of pre-existing fixes fell out of this work: A block-device freeze racing a btrfs device change could leave the whole filesystem stuck frozen. A bdev_freeze() issued by "dmsetup suspend" or an LVM snapshot resolves that holder to freeze the filesystem. and bdev_thaw() resolves it again to thaw. A freeze landing while btrfs is adding, removing or replacing a device freezes the filesystem. The membership change then drops that link. So the matching thaw could no longer find the superblock. Forbid freezing a device for the duration of a membership change, modelled on deny_write_access()/allow_write_access(). * tag 'vfs-7.3-rc1.super' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (24 commits) super: fix dying superblock warning messages block: reject block device inodes with i_rdev == 0 in lookup_bdev() selftests/filesystems: add ustat() coverage fs: look up the superblock via the device table in user_get_super() super: make fs_holder_ops private f2fs: open via dedicated fs bdev helpers erofs: open via dedicated fs bdev helpers fs: tolerate per-superblock freeze errors on shared devices fs: look up superblocks via the device table in fs_holder_ops ext4: open via dedicated fs bdev helpers btrfs: open via dedicated fs bdev helpers xfs: port to fs_bdev_file_open_by_path() fs: add dedicated block device open helpers for filesystems fs: maintain a global device-to-superblock table ocfs2: don't reset s_dev on dismount ext4: use anonymous devices for KUnit test superblocks fs, block: move blk_mode_t and fop_flags_t into <linux/types.h> super: take lock after last reference count super: convert s_count to refcount_t s_passive btrfs: deny freezing devices undergoing a replace ...
Add a regression test for the fsuidgid_has_mapping() check in
vfs_tmpfile(). It idmaps a detached tmpfs mount so that the
caller-visible id range [0, 10000) maps onto the on-disk range
[10000, 20000) and checks that:
- a caller whose fsuid/fsgid fall outside that range cannot create an
O_TMPFILE through the mount and gets -EOVERFLOW instead of an inode
owned by (uid_t)-1;
- a mapped caller can create an O_TMPFILE, link it into the namespace,
and the ownership round-trips through the mount idmap: it is reported
as 0 through the mount and stored as 10000 on the underlying tmpfs.
The test runs entirely as root and uses setfsuid()/setfsgid() to become
the unmapped caller, so it needs no helper user. The layer directory is
world-writable so that an unmapped caller still clears the directory
permission check and reaches the fsuidgid_has_mapping() test.
Link: https://patch.msgid.link/20260615-work-idmapped-tmpfile-v1-2-754a94d81f83@kernel.org
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
user_get_super() is now backed by the global device-to-superblock table instead of a walk of the super_blocks list. ustat(2) is its most direct user-visible consumer but nothing in the tree exercises it. Add a small regression test: the device number of a mounted tmpfs (an anonymous device, registered in the table by sget_fc()) must resolve, it must stop resolving after the unmount (the entry is dropped again in kill_super_notify()), and bogus device numbers keep reporting EINVAL. The test passes on kernels before the conversion: it pins down the semantics the table-backed lookup must preserve. Link: https://patch.msgid.link/20260616-work-super-bdev_holder_global-v2-18-7df6b864028e@kernel.org Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
Signed-off-by: Aleksa Sarai <cyphar@cyphar.com> Link: https://lore.kernel.org/20250807-fscontext-log-cleanups-v3-2-8d91d6242dc3@cyphar.com Signed-off-by: Christian Brauner <brauner@kernel.org>
Make sure that listxattr() returns zero and that getxattr() returns ENODATA when no extended attributs are set. Use /sys/kernel/warn_count as that always exists and is a read-only file. Link: https://lore.kernel.org/20250702-hochmoderne-abklatsch-af9c605b57b2@brauner Signed-off-by: Christian Brauner <brauner@kernel.org>
Test that anonymous inodes cannot be chown()ed. Link: https://lore.kernel.org/20250407-work-anon_inode-v1-6-53a44c20d44e@kernel.org Reviewed-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Christian Brauner <brauner@kernel.org>
Add a simple file stressor that lives directly in-tree. This will create
a bunch of processes that each open 500 file descriptors and then use
close_range() to close them all.
Concurrently, other processes read /proc/<pid>/fd/ which rougly does
f = fget_task_next(p, &fd);
if (!f)
break;
data.mode = f->f_mode;
fput(f);
Which means that it'll try to get a reference to a file in another
task's file descriptor table.
Under heavy file load it is increasingly likely that the other task will
manage to close @file and @file will be recycled due to
SLAB_TYPEAFE_BY_RCU concurrently. This will trigger various warnings in
the file reference counting code.
Link: https://lore.kernel.org/r/20241021-vergab-streuen-924df15dceb9@brauner
Signed-off-by: Christian Brauner <brauner@kernel.org>
Use $(KHDR_INCLUDES) as lookup path for kernel headers. This prevents building against kernel headers from the build environment in scenarios where kernel headers are installed into a specific output directory (O=...). Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Shuah Khan <shuah@kernel.org> Cc: linux-kselftest@vger.kernel.org Cc: Ingo Molnar <mingo@redhat.com> Cc: <stable@vger.kernel.org> # 5.18+ Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
We were picking up the wrong header should use asm/ioctls.h form the kernel
and not the header from the system (sys/ioctl.h). In the current code we
added the correct include and we added the kernel headers path to the CFLAGS.
Fixes: ce290a19609d ("selftests: add devpts selftests")
Signed-off-by: Anders Roxell <anders.roxell@linaro.org>
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
Signed-off-by: Shuah Khan (Samsung OSG) <shuah@kernel.org>
In commit ce290a19609d ("selftests: add devpts selftests"), the
filesystems directory was added to the top-level selftests Makefile.
That had the effect of causing the existing dnotify_test in the
filesystems directory to now be run as part of the default selftests
test-run. Unfortunately dnotify_test is actually an infinite loop.
Fix it by moving dnotify_test to TEST_GEN_PROGS_EXTENDED, which says
that it's a generated file (ie. built) but should not be run as part
of the default test suite run (it's an "extended" test).
While we're here cleanup a few other things, devpts_pts should be in
TEST_GEN_PROGS to indicate that it's built, and with the above two
changes we no longer need a custom all or clean rule.
Fixes: ce290a19609d ("selftests: add devpts selftests")
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Acked-by: Christian brauner <christian.brauner@ubuntu.com>
Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>