Commit Graph

248 Commits

Author SHA1 Message Date
Christian Brauner
4e32c25b58 libfs: fix get_stashed_dentry()
get_stashed_dentry() tries to optimistically retrieve a stashed dentry
from a provided location.  It needs to ensure to hold rcu lock before it
dereference the stashed location to prevent UAF issues.  Use
rcu_dereference() instead of READ_ONCE() it's effectively equivalent
with some lockdep bells and whistles and it communicates clearly that
this expects rcu protection.

Link: https://lore.kernel.org/r/20240906-vfs-hotfix-5959800ffa68@brauner
Fixes: 07fd7c3298 ("libfs: add path_from_stashed()")
Reported-by: syzbot+f82b36bffae7ef78b6a7@syzkaller.appspotmail.com
Fixes: syzbot+f82b36bffae7ef78b6a7@syzkaller.appspotmail.com
Reported-by: syzbot+cbe4b96e1194b0e34db6@syzkaller.appspotmail.com
Fixes: syzbot+cbe4b96e1194b0e34db6@syzkaller.appspotmail.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2024-09-06 11:08:58 -07:00
yangerkun
64a7ce76fb
libfs: fix infinite directory reads for offset dir
After we switch tmpfs dir operations from simple_dir_operations to
simple_offset_dir_operations, every rename happened will fill new dentry
to dest dir's maple tree(&SHMEM_I(inode)->dir_offsets->mt) with a free
key starting with octx->newx_offset, and then set newx_offset equals to
free key + 1. This will lead to infinite readdir combine with rename
happened at the same time, which fail generic/736 in xfstests(detail show
as below).

1. create 5000 files(1 2 3...) under one dir
2. call readdir(man 3 readdir) once, and get one entry
3. rename(entry, "TEMPFILE"), then rename("TEMPFILE", entry)
4. loop 2~3, until readdir return nothing or we loop too many
   times(tmpfs break test with the second condition)

We choose the same logic what commit 9b378f6ad4 ("btrfs: fix infinite
directory reads") to fix it, record the last_index when we open dir, and
do not emit the entry which index >= last_index. The file->private_data
now used in offset dir can use directly to do this, and we also update
the last_index when we llseek the dir file.

Fixes: a2e459555c ("shmem: stable directory offsets")
Signed-off-by: yangerkun <yangerkun@huawei.com>
Link: https://lore.kernel.org/r/20240731043835.1828697-1-yangerkun@huawei.com
Reviewed-by: Chuck Lever <chuck.lever@oracle.com>
[brauner: only update last_index after seek when offset is zero like Jan suggested]
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-08-12 22:03:26 +02:00
Gabriel Krisman Bertazi
6a79a4e187
libfs: Introduce case-insensitive string comparison helper
generic_ci_match can be used by case-insensitive filesystems to compare
strings under lookup with dirents in a case-insensitive way.  This
function is currently reimplemented by each filesystem supporting
casefolding, so this reduces code duplication in filesystem-specific
code.

[eugen.hristev@collabora.com: rework to first test the exact match, cleanup
and add error message]

Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com>
Signed-off-by: Eugen Hristev <eugen.hristev@collabora.com>
Link: https://lore.kernel.org/r/20240606073353.47130-4-eugen.hristev@collabora.com
Reviewed-by: Gabriel Krisman Bertazi <krisman@suse.de>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-06-07 17:00:44 +02:00
Chuck Lever
ad191eb6d6
shmem: Fix shmem_rename2()
When renaming onto an existing directory entry, user space expects
the replacement entry to have the same directory offset as the
original one.

Link: https://gitlab.alpinelinux.org/alpine/aports/-/issues/15966
Fixes: a2e459555c ("shmem: stable directory offsets")
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Link: https://lore.kernel.org/r/20240415152057.4605-4-cel@kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-04-17 13:49:44 +02:00
Chuck Lever
5a1a25be99
libfs: Add simple_offset_rename() API
I'm about to fix a tmpfs rename bug that requires the use of
internal simple_offset helpers that are not available in mm/shmem.c

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Link: https://lore.kernel.org/r/20240415152057.4605-3-cel@kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-04-17 13:49:43 +02:00
Chuck Lever
23cdd0eed3
libfs: Fix simple_offset_rename_exchange()
User space expects the replacement (old) directory entry to have
the same directory offset after the rename.

Suggested-by: Christian Brauner <brauner@kernel.org>
Fixes: a2e459555c ("shmem: stable directory offsets")
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Link: https://lore.kernel.org/r/20240415152057.4605-2-cel@kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-04-17 13:49:43 +02:00
Christian Brauner
9d9539db86 pidfs: remove config option
As Linus suggested this enables pidfs unconditionally. A key property to
retain is the ability to compare pidfds by inode number (cf. [1]).
That's extremely helpful just as comparing namespace file descriptors by
inode number is. They are used in a variety of scenarios where they need
to be compared, e.g., when receiving a pidfd via SO_PEERPIDFD from a
socket to trivially authenticate a the sender and various other
use-cases.

For 64bit systems this is pretty trivial to do. For 32bit it's slightly
more annoying as we discussed but we simply add a dumb ida based
allocator that gets used on 32bit. This gives the same guarantees about
inode numbers on 64bit without any overflow risk. Practically, we'll
never run into overflow issues because we're constrained by the number
of processes that can exist on 32bit and by the number of open files
that can exist on a 32bit system. On 64bit none of this matters and
things are very simple.

If 32bit also needs the uniqueness guarantee they can simply parse the
contents of /proc/<pid>/fd/<nr>. The uniqueness guarantees have a
variety of use-cases. One of the most obvious ones is that they will
make pidfiles (or "pidfdfiles", I guess) reliable as the unique
identifier can be placed into there that won't be reycled. Also a
frequent request.

Note, I took the chance and simplified path_from_stashed() even further.
Instead of passing the inode number explicitly to path_from_stashed() we
let the filesystem handle that internally. So path_from_stashed() ends
up even simpler than it is now. This is also a good solution allowing
the cleanup code to be clean and consistent between 32bit and 64bit. The
cleanup path in prepare_anon_dentry() is also switched around so we put
the inode before the dentry allocation. This means we only have to call
the cleanup handler for the filesystem's inode data once and can rely
->evict_inode() otherwise.

Aside from having to have a bit of extra code for 32bit it actually ends
up a nice cleanup for path_from_stashed() imho.

Tested on both 32 and 64bit including error injection.

Link: https://github.com/systemd/systemd/pull/31713 [1]
Link: https://lore.kernel.org/r/20240312-dingo-sehnlich-b3ecc35c6de7@brauner
Signed-off-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2024-03-13 12:53:53 -07:00
Linus Torvalds
0c750012e8 vfs-6.9.file
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Merge tag 'vfs-6.9.file' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

Pull file locking updates from Christian Brauner:
 "A few years ago struct file_lock_context was added to allow for
  separate lists to track different types of file locks instead of using
  a singly-linked list for all of them.

  Now leases no longer need to be tracked using struct file_lock.
  However, a lot of the infrastructure is identical for leases and locks
  so separating them isn't trivial.

  This splits a group of fields used by both file locks and leases into
  a new struct file_lock_core. The new core struct is embedded in struct
  file_lock. Coccinelle was used to convert a lot of the callers to deal
  with the move, with the remaining 25% or so converted by hand.

  Afterwards several internal functions in fs/locks.c are made to work
  with struct file_lock_core. Ultimately this allows to split struct
  file_lock into struct file_lock and struct file_lease. The file lease
  APIs are then converted to take struct file_lease"

* tag 'vfs-6.9.file' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (51 commits)
  filelock: fix deadlock detection in POSIX locking
  filelock: always define for_each_file_lock()
  smb: remove redundant check
  filelock: don't do security checks on nfsd setlease calls
  filelock: split leases out of struct file_lock
  filelock: remove temporary compatibility macros
  smb/server: adapt to breakup of struct file_lock
  smb/client: adapt to breakup of struct file_lock
  ocfs2: adapt to breakup of struct file_lock
  nfsd: adapt to breakup of struct file_lock
  nfs: adapt to breakup of struct file_lock
  lockd: adapt to breakup of struct file_lock
  fuse: adapt to breakup of struct file_lock
  gfs2: adapt to breakup of struct file_lock
  dlm: adapt to breakup of struct file_lock
  ceph: adapt to breakup of struct file_lock
  afs: adapt to breakup of struct file_lock
  9p: adapt to breakup of struct file_lock
  filelock: convert seqfile handling to use file_lock_core
  filelock: convert locks_translate_pid to take file_lock_core
  ...
2024-03-11 10:37:45 -07:00
Linus Torvalds
b5683a37c8 vfs-6.9.pidfd
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Merge tag 'vfs-6.9.pidfd' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

Pull pdfd updates from Christian Brauner:

 - Until now pidfds could only be created for thread-group leaders but
   not for threads. There was no technical reason for this. We simply
   had no users that needed support for this. Now we do have users that
   need support for this.

   This introduces a new PIDFD_THREAD flag for pidfd_open(). If that
   flag is set pidfd_open() creates a pidfd that refers to a specific
   thread.

   In addition, we now allow clone() and clone3() to be called with
   CLONE_PIDFD | CLONE_THREAD which wasn't possible before.

   A pidfd that refers to an individual thread differs from a pidfd that
   refers to a thread-group leader:

    (1) Pidfds are pollable. A task may poll a pidfd and get notified
        when the task has exited.

        For thread-group leader pidfds the polling task is woken if the
        thread-group is empty. In other words, if the thread-group
        leader task exits when there are still threads alive in its
        thread-group the polling task will not be woken when the
        thread-group leader exits but rather when the last thread in the
        thread-group exits.

        For thread-specific pidfds the polling task is woken if the
        thread exits.

    (2) Passing a thread-group leader pidfd to pidfd_send_signal() will
        generate thread-group directed signals like kill(2) does.

        Passing a thread-specific pidfd to pidfd_send_signal() will
        generate thread-specific signals like tgkill(2) does.

        The default scope of the signal is thus determined by the type
        of the pidfd.

        Since use-cases exist where the default scope of the provided
        pidfd needs to be overriden the following flags are added to
        pidfd_send_signal():

         - PIDFD_SIGNAL_THREAD
           Send a thread-specific signal.

         - PIDFD_SIGNAL_THREAD_GROUP
           Send a thread-group directed signal.

         - PIDFD_SIGNAL_PROCESS_GROUP
           Send a process-group directed signal.

        The scope change will only work if the struct pid is actually
        used for this scope.

        For example, in order to send a thread-group directed signal the
        provided pidfd must be used as a thread-group leader and
        similarly for PIDFD_SIGNAL_PROCESS_GROUP the struct pid must be
        used as a process group leader.

 - Move pidfds from the anonymous inode infrastructure to a tiny pseudo
   filesystem. This will unblock further work that we weren't able to do
   simply because of the very justified limitations of anonymous inodes.
   Moving pidfds to a tiny pseudo filesystem allows for statx on pidfds
   to become useful for the first time. They can now be compared by
   inode number which are unique for the system lifetime.

   Instead of stashing struct pid in file->private_data we can now stash
   it in inode->i_private. This makes it possible to introduce concepts
   that operate on a process once all file descriptors have been closed.
   A concrete example is kill-on-last-close. Another side-effect is that
   file->private_data is now freed up for per-file options for pidfds.

   Now, each struct pid will refer to a different inode but the same
   struct pid will refer to the same inode if it's opened multiple
   times. In contrast to now where each struct pid refers to the same
   inode.

   The tiny pseudo filesystem is not visible anywhere in userspace
   exactly like e.g., pipefs and sockfs. There's no lookup, there's no
   complex inode operations, nothing. Dentries and inodes are always
   deleted when the last pidfd is closed.

   We allocate a new inode and dentry for each struct pid and we reuse
   that inode and dentry for all pidfds that refer to the same struct
   pid. The code is entirely optional and fairly small. If it's not
   selected we fallback to anonymous inodes. Heavily inspired by nsfs.

   The dentry and inode allocation mechanism is moved into generic
   infrastructure that is now shared between nsfs and pidfs. The
   path_from_stashed() helper must be provided with a stashing location,
   an inode number, a mount, and the private data that is supposed to be
   used and it will provide a path that can be passed to dentry_open().

   The helper will try retrieve an existing dentry from the provided
   stashing location. If a valid dentry is found it is reused. If not a
   new one is allocated and we try to stash it in the provided location.
   If this fails we retry until we either find an existing dentry or the
   newly allocated dentry could be stashed. Subsequent openers of the
   same namespace or task are then able to reuse it.

 - Currently it is only possible to get notified when a task has exited,
   i.e., become a zombie and userspace gets notified with EPOLLIN. We
   now also support waiting until the task has been reaped, notifying
   userspace with EPOLLHUP.

 - Ensure that ESRCH is reported for getfd if a task is exiting instead
   of the confusing EBADF.

 - Various smaller cleanups to pidfd functions.

* tag 'vfs-6.9.pidfd' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (23 commits)
  libfs: improve path_from_stashed()
  libfs: add stashed_dentry_prune()
  libfs: improve path_from_stashed() helper
  pidfs: convert to path_from_stashed() helper
  nsfs: convert to path_from_stashed() helper
  libfs: add path_from_stashed()
  pidfd: add pidfs
  pidfd: move struct pidfd_fops
  pidfd: allow to override signal scope in pidfd_send_signal()
  pidfd: change pidfd_send_signal() to respect PIDFD_THREAD
  signal: fill in si_code in prepare_kill_siginfo()
  selftests: add ESRCH tests for pidfd_getfd()
  pidfd: getfd should always report ESRCH if a task is exiting
  pidfd: clone: allow CLONE_THREAD | CLONE_PIDFD together
  pidfd: exit: kill the no longer used thread_group_exited()
  pidfd: change do_notify_pidfd() to use __wake_up(poll_to_key(EPOLLIN))
  pid: kill the obsolete PIDTYPE_PID code in transfer_pid()
  pidfd: kill the no longer needed do_notify_pidfd() in de_thread()
  pidfd_poll: report POLLHUP when pid_task() == NULL
  pidfd: implement PIDFD_THREAD flag for pidfd_open()
  ...
2024-03-11 10:21:06 -07:00
Christian Brauner
09406ad8e5 case-insensitive updates for 6.9
- Patch case-insensitive lookup by trying the case-exact comparison
 first, before falling back to costly utf8 casefolded comparison.
 
 - Fix to forbid using a case-insensitive directory as part of an
 overlayfs mount.
 
 - Patchset to ensure d_op are set at d_alloc time for fscrypt and
 casefold volumes, ensuring filesystem dentries will all have the correct
 ops, whether they come from a lookup or not.
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Merge tag 'for-next-6.9' of ssh://gitolite.kernel.org/pub/scm/linux/kernel/git/krisman/unicode into vfs.misc

Merge case-insensitive updates from Gabriel Krisman Bertazi:

- Patch case-insensitive lookup by trying the case-exact comparison
  first, before falling back to costly utf8 casefolded comparison.

- Fix to forbid using a case-insensitive directory as part of an
  overlayfs mount.

- Patchset to ensure d_op are set at d_alloc time for fscrypt and
  casefold volumes, ensuring filesystem dentries will all have the
  correct ops, whether they come from a lookup or not.

* tag 'for-next-6.9' of ssh://gitolite.kernel.org/pub/scm/linux/kernel/git/krisman/unicode:
  libfs: Drop generic_set_encrypted_ci_d_ops
  ubifs: Configure dentry operations at dentry-creation time
  f2fs: Configure dentry operations at dentry-creation time
  ext4: Configure dentry operations at dentry-creation time
  libfs: Add helper to choose dentry operations at mount-time
  libfs: Merge encrypted_ci_dentry_ops and ci_dentry_ops
  fscrypt: Drop d_revalidate once the key is added
  fscrypt: Drop d_revalidate for valid dentries during lookup
  fscrypt: Factor out a helper to configure the lookup dentry
  ovl: Always reject mounting over case-insensitive directories
  libfs: Attempt exact-match comparison first during casefolded lookup

Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-03-07 11:55:41 +01:00
Christian Brauner
e9c5263ce1
libfs: improve path_from_stashed()
Right now we pass a bunch of info that is fs specific which doesn't make
a lot of sense and it bleeds fs sepcific details into the generic
helper. nsfs and pidfs have slightly different needs when initializing
inodes. Add simple operations that are stashed in sb->s_fs_info that
both can implement. This also allows us to get rid of cleaning up
references in the caller. All in all path_from_stashed() becomes way
simpler.

Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-03-01 22:31:40 +01:00
Christian Brauner
2558e3b231
libfs: add stashed_dentry_prune()
Both pidfs and nsfs use a memory location to stash a dentry for reuse by
concurrent openers. Right now two custom
dentry->d_prune::{ns,pidfs}_prune_dentry() methods are needed that do
the same thing. The only thing that differs is that they need to get to
the memory location to store or retrieve the dentry from differently.
Fix that by remember the stashing location for the dentry in
dentry->d_fsdata which allows us to retrieve it in dentry->d_prune. That
in turn makes it possible to add a common helper that pidfs and nsfs can
both use.

Link: https://lore.kernel.org/r/CAHk-=wg8cHY=i3m6RnXQ2Y2W8psicKWQEZq1=94ivUiviM-0OA@mail.gmail.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-03-01 12:26:29 +01:00
Christian Brauner
159a0d9fd5
libfs: improve path_from_stashed() helper
In earlier patches we moved both nsfs and pidfs to path_from_stashed().
The helper currently tries to add and stash a new dentry if a reusable
dentry couldn't be found and returns EAGAIN if it lost the race to stash
the dentry. The caller can use EAGAIN to retry.

The helper and the two filesystems be written in a way that makes
returning EAGAIN unnecessary. To do this we need to change the
dentry->d_prune() implementation of nsfs and pidfs to not simply replace
the stashed dentry with NULL but to use a cmpxchg() and only replace
their own dentry.

Then path_from_stashed() can then be changed to not just stash a new
dentry when no dentry is currently stashed but also when an already dead
dentry is stashed. If another task managed to install a dentry in the
meantime it can simply be reused. Pack that into a loop and call it a
day.

Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/CAHk-=wgtLF5Z5=15-LKAczWm=-tUjHO+Bpf7WjBG+UU3s=fEQw@mail.gmail.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-03-01 12:26:23 +01:00
Christian Brauner
b28ddcc32d
pidfs: convert to path_from_stashed() helper
Moving pidfds from the anonymous inode infrastructure to a separate tiny
in-kernel filesystem similar to sockfs, pipefs, and anon_inodefs causes
selinux denials and thus various userspace components that make heavy
use of pidfds to fail as pidfds used anon_inode_getfile() which aren't
subject to any LSM hooks. But dentry_open() is and that would cause
regressions.

The failures that are seen are selinux denials. But the core failure is
dbus-broker. That cascades into other services failing that depend on
dbus-broker. For example, when dbus-broker fails to start polkit and all
the others won't be able to work because they depend on dbus-broker.

The reason for dbus-broker failing is because it doesn't handle failures
for SO_PEERPIDFD correctly. Last kernel release we introduced
SO_PEERPIDFD (and SCM_PIDFD). SO_PEERPIDFD allows dbus-broker and polkit
and others to receive a pidfd for the peer of an AF_UNIX socket. This is
the first time in the history of Linux that we can safely authenticate
clients in a race-free manner.

dbus-broker immediately made use of this but messed up the error
checking. It only allowed EINVAL as a valid failure for SO_PEERPIDFD.
That's obviously problematic not just because of LSM denials but because
of seccomp denials that would prevent SO_PEERPIDFD from working; or any
other new error code from there.

So this is catching a flawed implementation in dbus-broker as well. It
has to fallback to the old pid-based authentication when SO_PEERPIDFD
doesn't work no matter the reasons otherwise it'll always risk such
failures. So overall that LSM denial should not have caused dbus-broker
to fail. It can never assume that a feature released one kernel ago like
SO_PEERPIDFD can be assumed to be available.

So, the next fix separate from the selinux policy update is to try and
fix dbus-broker at [3]. That should make it into Fedora as well. In
addition the selinux reference policy should also be updated. See [4]
for that. If Selinux is in enforcing mode in userspace and it encounters
anything that it doesn't know about it will deny it by default. And the
policy is entirely in userspace including declaring new types for stuff
like nsfs or pidfs to allow it.

For now we continue to raise S_PRIVATE on the inode if it's a pidfs
inode which means things behave exactly like before.

Link: https://bugzilla.redhat.com/show_bug.cgi?id=2265630
Link: https://github.com/fedora-selinux/selinux-policy/pull/2050
Link: https://github.com/bus1/dbus-broker/pull/343 [3]
Link: https://github.com/SELinuxProject/refpolicy/pull/762 [4]
Reported-by: Nathan Chancellor <nathan@kernel.org>
Link: https://lore.kernel.org/r/20240222190334.GA412503@dev-arch.thelio-3990X
Link: https://lore.kernel.org/r/20240218-neufahrzeuge-brauhaus-fb0eb6459771@brauner
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-03-01 12:24:53 +01:00
Christian Brauner
07fd7c3298
libfs: add path_from_stashed()
Add a helper for both nsfs and pidfs to reuse an already stashed dentry
or to add and stash a new dentry.

Link: https://lore.kernel.org/r/20240218-neufahrzeuge-brauhaus-fb0eb6459771@brauner
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-03-01 12:23:44 +01:00
Gabriel Krisman Bertazi
101c3fad29 libfs: Drop generic_set_encrypted_ci_d_ops
No filesystems depend on it anymore, and it is generally a bad idea.
Since all dentries should have the same set of dentry operations in
case-insensitive capable filesystems, it should be propagated through
->s_d_op.

Reviewed-by: Eric Biggers <ebiggers@google.com>
Link: https://lore.kernel.org/r/20240221171412.10710-11-krisman@suse.de
Signed-off-by: Gabriel Krisman Bertazi <krisman@suse.de>
2024-02-27 16:55:35 -05:00
Gabriel Krisman Bertazi
70dfe3f0d2 libfs: Add helper to choose dentry operations at mount-time
In preparation to drop the similar helper that sets d_op at lookup time,
add a version to set the right d_op filesystem-wide, through sb->s_d_op.
The operations structures are shared across filesystems supporting
fscrypt and/or casefolding, therefore we can keep it in common libfs
code.

Reviewed-by: Eric Biggers <ebiggers@google.com>
Link: https://lore.kernel.org/r/20240221171412.10710-7-krisman@suse.de
Signed-off-by: Gabriel Krisman Bertazi <krisman@suse.de>
2024-02-27 16:55:34 -05:00
Gabriel Krisman Bertazi
e6ca2883d9 libfs: Merge encrypted_ci_dentry_ops and ci_dentry_ops
In preparation to get case-insensitive dentry operations from sb->s_d_op
again, use the same structure with and without fscrypt.

Reviewed-by: Eric Biggers <ebiggers@google.com>
Link: https://lore.kernel.org/r/20240221171412.10710-6-krisman@suse.de
Signed-off-by: Gabriel Krisman Bertazi <krisman@suse.de>
2024-02-27 16:55:34 -05:00
Gabriel Krisman Bertazi
0906fbb2f7 libfs: Attempt exact-match comparison first during casefolded lookup
Casefolded comparisons are (obviously) way more costly than a simple
memcmp.  Try the case-sensitive comparison first, falling-back to the
case-insensitive lookup only when needed.  This allows any exact-match
lookup to complete without having to walk the utf8 trie.

Note that, for strict mode, generic_ci_d_compare used to reject an
invalid UTF-8 string, which would now be considered valid if it
exact-matches the disk-name.  But, if that is the case, the filesystem
is corrupt.  More than that, it really doesn't matter in practice,
because the name-under-lookup will have already been rejected by
generic_ci_d_hash and we won't even get here.

The memcmp is safe under RCU because we are operating on str/len instead
of dentry->d_name directly, and the caller guarantees their consistency
between each other in __d_lookup_rcu_op_compare.

Link: https://lore.kernel.org/r/87ttn2sip7.fsf_-_@mailhost.krisman.be
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Gabriel Krisman Bertazi <krisman@suse.de>
2024-02-27 16:55:25 -05:00
Christian Brauner
4af6ccb469
Merge series 'Use Maple Trees for simple_offset utilities' of https://lore.kernel.org/r/170820083431.6328.16233178852085891453.stgit@91.116.238.104.host.secureserver.net
Pull simple offset series from Chuck Lever

In an effort to address slab fragmentation issues reported a few
months ago, I've replaced the use of xarrays for the directory
offset map in "simple" file systems (including tmpfs).

Thanks to Liam Howlett for helping me get this working with Maple
Trees.

* series 'Use Maple Trees for simple_offset utilities' of https://lore.kernel.org/r/170820083431.6328.16233178852085891453.stgit@91.116.238.104.host.secureserver.net: (6 commits)
  libfs: Convert simple directory offsets to use a Maple Tree
  test_maple_tree: testing the cyclic allocation
  maple_tree: Add mtree_alloc_cyclic()
  libfs: Add simple_offset_empty()
  libfs: Define a minimum directory offset
  libfs: Re-arrange locking in offset_iterate_dir()

Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-02-22 10:03:26 +01:00
Chuck Lever
0e4a862174 libfs: Convert simple directory offsets to use a Maple Tree
Test robot reports:
> kernel test robot noticed a -19.0% regression of aim9.disk_src.ops_per_sec on:
>
> commit: a2e459555c ("shmem: stable directory offsets")
> https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git master

Feng Tang further clarifies that:
> ... the new simple_offset_add()
> called by shmem_mknod() brings extra cost related with slab,
> specifically the 'radix_tree_node', which cause the regression.

Willy's analysis is that, over time, the test workload causes
xa_alloc_cyclic() to fragment the underlying SLAB cache.

This patch replaces the offset_ctx's xarray with a Maple Tree in the
hope that Maple Tree's dense node mode will handle this scenario
more scalably.

In addition, we can widen the simple directory offset maximum to
signed long (as loff_t is also signed).

Suggested-by: Matthew Wilcox <willy@infradead.org>
Reported-by: kernel test robot <oliver.sang@intel.com>
Closes: https://lore.kernel.org/oe-lkp/202309081306.3ecb3734-oliver.sang@intel.com
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Link: https://lore.kernel.org/r/170820145616.6328.12620992971699079156.stgit@91.116.238.104.host.secureserver.net
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-02-21 09:34:26 +01:00
Chuck Lever
ecba88a3b3 libfs: Add simple_offset_empty()
For simple filesystems that use directory offset mapping, rely
strictly on the directory offset map to tell when a directory has
no children.

After this patch is applied, the emptiness test holds only the RCU
read lock when the directory being tested has no children.

In addition, this adds another layer of confirmation that
simple_offset_add/remove() are working as expected.

Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Link: https://lore.kernel.org/r/170820143463.6328.7872919188371286951.stgit@91.116.238.104.host.secureserver.net
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-02-21 09:34:25 +01:00
Chuck Lever
7beea725a8 libfs: Define a minimum directory offset
This value is used in several places, so make it a symbolic
constant.

Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Link: https://lore.kernel.org/r/170820142741.6328.12428356024575347885.stgit@91.116.238.104.host.secureserver.net
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-02-21 09:34:25 +01:00
Chuck Lever
3f6d810665 libfs: Re-arrange locking in offset_iterate_dir()
Liam and Matthew say that once the RCU read lock is released,
xa_state is not safe to re-use for the next xas_find() call. But the
RCU read lock must be released on each loop iteration so that
dput(), which might_sleep(), can be called safely.

Thus we are forced to walk the offset tree with fresh state for each
directory entry. xa_find() can do this for us, though it might be a
little less efficient than maintaining xa_state locally.

We believe that in the current code base, inode->i_rwsem provides
protection for the xa_state maintained in
offset_iterate_dir(). However, there is no guarantee that will
continue to be the case in the future.

Since offset_iterate_dir() doesn't build xa_state locally any more,
there's no longer a strong need for offset_find_next(). Clean up by
rolling these two helpers together.

Suggested-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Message-ID: <170785993027.11135.8830043889278631735.stgit@91.116.238.104.host.secureserver.net>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Link: https://lore.kernel.org/r/170820142021.6328.15047865406275957018.stgit@91.116.238.104.host.secureserver.net
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-02-21 09:34:25 +01:00
Li zeming
bae8bc4698 libfs: Remove unnecessary ‘0’ values from ret
ret is assigned first, so it does not need to initialize the assignment.

Signed-off-by: Li zeming <zeming@nfschina.com>
Link: https://lore.kernel.org/r/20240220062030.114203-1-zeming@nfschina.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-02-20 10:24:48 +01:00
Jeff Layton
c69ff40719
filelock: split leases out of struct file_lock
Add a new struct file_lease and move the lease-specific fields from
struct file_lock to it. Convert the appropriate API calls to take
struct file_lease instead, and convert the callers to use them.

There is zero overlap between the lock manager operations for file
locks and the ones for file leases, so split the lease-related
operations off into a new lease_manager_operations struct.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
Link: https://lore.kernel.org/r/20240131-flsplit-v3-47-c6129007ee8d@kernel.org
Reviewed-by: NeilBrown <neilb@suse.de>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-02-05 13:11:44 +01:00
Linus Torvalds
499aa1ca4e dcache stuff for this cycle
change of locking rules for __dentry_kill(), regularized refcounting
 rules in that area, assorted cleanups and removal of weird corner
 cases (e.g. now ->d_iput() on child is always called before the parent
 might hit __dentry_kill(), etc.)
 
 Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Merge tag 'pull-dcache' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull dcache updates from Al Viro:
 "Change of locking rules for __dentry_kill(), regularized refcounting
  rules in that area, assorted cleanups and removal of weird corner
  cases (e.g. now ->d_iput() on child is always called before the parent
  might hit __dentry_kill(), etc)"

* tag 'pull-dcache' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (40 commits)
  dcache: remove unnecessary NULL check in dget_dlock()
  kill DCACHE_MAY_FREE
  __d_unalias() doesn't use inode argument
  d_alloc_parallel(): in-lookup hash insertion doesn't need an RCU variant
  get rid of DCACHE_GENOCIDE
  d_genocide(): move the extern into fs/internal.h
  simple_fill_super(): don't bother with d_genocide() on failure
  nsfs: use d_make_root()
  d_alloc_pseudo(): move setting ->d_op there from the (sole) caller
  kill d_instantate_anon(), fold __d_instantiate_anon() into remaining caller
  retain_dentry(): introduce a trimmed-down lockless variant
  __dentry_kill(): new locking scheme
  d_prune_aliases(): use a shrink list
  switch select_collect{,2}() to use of to_shrink_list()
  to_shrink_list(): call only if refcount is 0
  fold dentry_kill() into dput()
  don't try to cut corners in shrink_lock_dentry()
  fold the call of retain_dentry() into fast_dput()
  Call retain_dentry() with refcount 0
  dentry_kill(): don't bother with retain_dentry() on slow path
  ...
2024-01-11 20:11:35 -08:00
Al Viro
119dcc73a9 Merge branches 'work.dcache-misc' and 'work.dcache2' into work.dcache 2023-11-25 02:51:35 -05:00
Al Viro
715cd66aab simple_fill_super(): don't bother with d_genocide() on failure
Failing ->fill_super() will be followed by ->kill_sb(), which should
include kill_litter_super() if the call of simple_fill_super() had
been asked to create anything besides the root dentry.  So there's
no need to empty the partially populated tree - it will be trimmed
by inevitable kill_litter_super().

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2023-11-25 02:50:11 -05:00
Al Viro
da549bdd15 dentry: switch the lists of children to hlist
Saves a pointer per struct dentry and actually makes the things less
clumsy.  Cleaned the d_walk() and dcache_readdir() a bit by use
of hlist_for_... iterators.

A couple of new helpers - d_first_child() and d_next_sibling(),
to make the expressions less awful.

Reviewed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2023-11-25 02:32:13 -05:00
Chuck Lever
796432efab
libfs: getdents() should return 0 after reaching EOD
The new directory offset helpers don't conform with the convention
of getdents() returning no more entries once a directory file
descriptor has reached the current end-of-directory.

To address this, copy the logic from dcache_readdir() to mark the
open directory file descriptor once EOD has been reached. Seeking
resets the mark.

Reported-by: Tavian Barnes <tavianator@tavianator.com>
Closes: https://lore.kernel.org/linux-fsdevel/20231113180616.2831430-1-tavianator@tavianator.com/
Fixes: 6faddda69f ("libfs: Add directory operations for stable offsets")
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Link: https://lore.kernel.org/r/170043792492.4628.15646203084646716134.stgit@bazille.1015granger.net
Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-11-20 15:34:22 +01:00
Linus Torvalds
13d88ac54d vfs-6.7.fsid
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Merge tag 'vfs-6.7.fsid' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

Pull vfs fanotify fsid updates from Christian Brauner:
 "This work is part of the plan to enable fanotify to serve as a drop-in
  replacement for inotify. While inotify is availabe on all filesystems,
  fanotify currently isn't.

  In order to support fanotify on all filesystems two things are needed:

   (1) all filesystems need to support AT_HANDLE_FID

   (2) all filesystems need to report a non-zero f_fsid

  This contains (1) and allows filesystems to encode non-decodable file
  handlers for fanotify without implementing any exportfs operations by
  encoding a file id of type FILEID_INO64_GEN from i_ino and
  i_generation.

  Filesystems that want to opt out of encoding non-decodable file ids
  for fanotify that don't support NFS export can do so by providing an
  empty export_operations struct.

  This also partially addresses (2) by generating f_fsid for simple
  filesystems as well as freevxfs. Remaining filesystems will be dealt
  with by separate patches.

  Finally, this contains the patch from the current exportfs maintainers
  which moves exportfs under vfs with Chuck, Jeff, and Amir as
  maintainers and vfs.git as tree"

* tag 'vfs-6.7.fsid' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
  MAINTAINERS: create an entry for exportfs
  fs: fix build error with CONFIG_EXPORTFS=m or not defined
  freevxfs: derive f_fsid from bdev->bd_dev
  fs: report f_fsid from s_dev for "simple" filesystems
  exportfs: support encoding non-decodeable file handles by default
  exportfs: define FILEID_INO64_GEN* file handle types
  exportfs: make ->encode_fh() a mandatory method for NFS export
  exportfs: add helpers to check if filesystem can encode/decode file handles
2023-11-07 12:11:26 -08:00
Amir Goldstein
d9e5d9221d
fs: fix build error with CONFIG_EXPORTFS=m or not defined
Many of the filesystems that call the generic exportfs helpers do not
select the EXPORTFS config.

Move generic_encode_ino32_fh() to libfs.c, same as generic_fh_to_*()
to avoid having to fix all those config dependencies.

Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202310262151.renqMvme-lkp@intel.com/
Fixes: dfaf653dc415 ("exportfs: make ->encode_fh() a mandatory method for NFS export")
Suggested-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Link: https://lore.kernel.org/r/20231026204540.143217-1-amir73il@gmail.com
Tested-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-10-28 16:16:19 +02:00
Amir Goldstein
ae62bcb5e7
fs: report f_fsid from s_dev for "simple" filesystems
There are many "simple" filesystems (*) that report null f_fsid in
statfs(2).  Those "simple" filesystems report sb->s_dev as the st_dev
field of the stat syscalls for all inodes of the filesystem (**).

In order to enable fanotify reporting of events with fsid on those
"simple" filesystems, report the sb->s_dev number in f_fsid field of
statfs(2).

(*) For most of the "simple" filesystem refered to in this commit, the
->statfs() operation is simple_statfs(). Some of those fs assign the
simple_statfs() method directly in their ->s_op struct and some assign it
indirectly via a call to simple_fill_super() or to pseudo_fs_fill_super()
with either custom or "simple" s_op.
We also make the same change to efivarfs and hugetlbfs, although they do
not use simple_statfs(), because they use the simple_* inode opreations
(e.g. simple_lookup()).

(**) For most of the "simple" filesystems, the ->getattr() method is not
assigned, so stat() is implemented by generic_fillattr().  A few "simple"
filesystem use the simple_getattr() method which also calls
generic_fillattr() to fill most of the stat struct.

The two exceptions are procfs and 9p. procfs implements several different
->getattr() methods, but they all end up calling generic_fillattr() to
fill the st_dev field from sb->s_dev.

9p has more complicated ->getattr() methods, but they too, end up calling
generic_fillattr() to fill the st_dev field from sb->s_dev.

Note that 9p and kernfs also call simple_statfs() from custom ->statfs()
methods which already fill the f_fsid field, but v9fs_statfs() calls
simple_statfs() only in case f_fsid was not filled and kenrfs_statfs()
overwrites f_fsid after calling simple_statfs().

Link: https://lore.kernel.org/r/20230919094820.g5bwharbmy2dq46w@quack3/
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Link: https://lore.kernel.org/r/20231023143049.2944970-1-amir73il@gmail.com
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-10-28 16:16:18 +02:00
Jeff Layton
077c212f03
fs: new accessor methods for atime and mtime
Recently, we converted the ctime accesses in the kernel to use new
accessor functions. Linus recently pointed out though that if we add
accessors for the atime and mtime, then that would allow us to
seamlessly change how these timestamps are stored in the inode.

Add new accessor functions for the atime and mtime that mirror the
accessors for the ctime.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
Link: https://lore.kernel.org/r/20231004185239.80830-1-jlayton@kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-10-18 13:26:14 +02:00
Al Viro
8287474aa5
direct_write_fallback(): on error revert the ->ki_pos update from buffered write
If we fail filemap_write_and_wait_range() on the range the buffered write went
into, we only report the "number of bytes which we direct-written", to quote
the comment in there.  Which is fine, but buffered write has already advanced
iocb->ki_pos, so we need to roll that back.  Otherwise we end up with e.g.
write(2) advancing position by more than the amount it reports having written.

Fixes: 182c25e9c1 "filemap: update ki_pos in generic_perform_write"
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Message-Id: <20230827214518.GU3390869@ZenIV>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-09-20 14:22:01 +02:00
Linus Torvalds
3ef96fcfd5 Many ext4 and jbd2 cleanups and bug fixes for v6.6-rc1.
* Cleanups in the ext4 remount code when going to and from read-only
   * Cleanups in ext4's multiblock allocator
   * Cleanups in the jbd2 setup/mounting code paths
   * Performance improvements when appending to a delayed allocation file
   * Miscenallenous syzbot and other bug fixes
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Merge tag 'ext4_for_linus-6.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4

Pull ext4 updates from Ted Ts'o:
 "Many ext4 and jbd2 cleanups and bug fixes:

   - Cleanups in the ext4 remount code when going to and from read-only

   - Cleanups in ext4's multiblock allocator

   - Cleanups in the jbd2 setup/mounting code paths

   - Performance improvements when appending to a delayed allocation file

   - Miscellaneous syzbot and other bug fixes"

* tag 'ext4_for_linus-6.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: (60 commits)
  ext4: fix slab-use-after-free in ext4_es_insert_extent()
  libfs: remove redundant checks of s_encoding
  ext4: remove redundant checks of s_encoding
  ext4: reject casefold inode flag without casefold feature
  ext4: use LIST_HEAD() to initialize the list_head in mballoc.c
  ext4: do not mark inode dirty every time when appending using delalloc
  ext4: rename s_error_work to s_sb_upd_work
  ext4: add periodic superblock update check
  ext4: drop dio overwrite only flag and associated warning
  ext4: add correct group descriptors and reserved GDT blocks to system zone
  ext4: remove unused function declaration
  ext4: mballoc: avoid garbage value from err
  ext4: use sbi instead of EXT4_SB(sb) in ext4_mb_new_blocks_simple()
  ext4: change the type of blocksize in ext4_mb_init_cache()
  ext4: fix unttached inode after power cut with orphan file feature enabled
  jbd2: correct the end of the journal recovery scan range
  ext4: ext4_get_{dev}_journal return proper error value
  ext4: cleanup ext4_get_dev_journal() and ext4_get_journal()
  jbd2: jbd2_journal_init_{dev,inode} return proper error return value
  jbd2: drop useless error tag in jbd2_journal_wipe()
  ...
2023-08-31 15:18:15 -07:00
Linus Torvalds
de16588a77 v6.6-vfs.misc
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Merge tag 'v6.6-vfs.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

Pull misc vfs updates from Christian Brauner:
 "This contains the usual miscellaneous features, cleanups, and fixes
  for vfs and individual filesystems.

  Features:

   - Block mode changes on symlinks and rectify our broken semantics

   - Report file modifications via fsnotify() for splice

   - Allow specifying an explicit timeout for the "rootwait" kernel
     command line option. This allows to timeout and reboot instead of
     always waiting indefinitely for the root device to show up

   - Use synchronous fput for the close system call

  Cleanups:

   - Get rid of open-coded lockdep workarounds for async io submitters
     and replace it all with a single consolidated helper

   - Simplify epoll allocation helper

   - Convert simple_write_begin and simple_write_end to use a folio

   - Convert page_cache_pipe_buf_confirm() to use a folio

   - Simplify __range_close to avoid pointless locking

   - Disable per-cpu buffer head cache for isolated cpus

   - Port ecryptfs to kmap_local_page() api

   - Remove redundant initialization of pointer buf in pipe code

   - Unexport the d_genocide() function which is only used within core
     vfs

   - Replace printk(KERN_ERR) and WARN_ON() with WARN()

  Fixes:

   - Fix various kernel-doc issues

   - Fix refcount underflow for eventfds when used as EFD_SEMAPHORE

   - Fix a mainly theoretical issue in devpts

   - Check the return value of __getblk() in reiserfs

   - Fix a racy assert in i_readcount_dec

   - Fix integer conversion issues in various functions

   - Fix LSM security context handling during automounts that prevented
     NFS superblock sharing"

* tag 'v6.6-vfs.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (39 commits)
  cachefiles: use kiocb_{start,end}_write() helpers
  ovl: use kiocb_{start,end}_write() helpers
  aio: use kiocb_{start,end}_write() helpers
  io_uring: use kiocb_{start,end}_write() helpers
  fs: create kiocb_{start,end}_write() helpers
  fs: add kerneldoc to file_{start,end}_write() helpers
  io_uring: rename kiocb_end_write() local helper
  splice: Convert page_cache_pipe_buf_confirm() to use a folio
  libfs: Convert simple_write_begin and simple_write_end to use a folio
  fs/dcache: Replace printk and WARN_ON by WARN
  fs/pipe: remove redundant initialization of pointer buf
  fs: Fix kernel-doc warnings
  devpts: Fix kernel-doc warnings
  doc: idmappings: fix an error and rephrase a paragraph
  init: Add support for rootwait timeout parameter
  vfs: fix up the assert in i_readcount_dec
  fs: Fix one kernel-doc comment
  docs: filesystems: idmappings: clarify from where idmappings are taken
  fs/buffer.c: disable per-CPU buffer_head cache for isolated CPUs
  vfs, security: Fix automount superblock LSM init problem, preventing NFS sb sharing
  ...
2023-08-28 10:17:14 -07:00
Linus Torvalds
ecd7db2047 v6.6-vfs.tmpfs
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Merge tag 'v6.6-vfs.tmpfs' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

Pull libfs and tmpfs updates from Christian Brauner:
 "This cycle saw a lot of work for tmpfs that required changes to the
  vfs layer. Andrew, Hugh, and I decided to take tmpfs through vfs this
  cycle. Things will go back to mm next cycle.

  Features
  ========

   - By far the biggest work is the quota support for tmpfs. New tmpfs
     quota infrastructure is added to support it and a new QFMT_SHMEM
     uapi option is exposed.

     This offers user and group quotas to tmpfs (project quotas will be
     added later). Similar to other filesystems tmpfs quota are not
     supported within user namespaces yet.

   - Add support for user xattrs. While tmpfs already supports security
     xattrs (security.*) and POSIX ACLs for a long time it lacked
     support for user xattrs (user.*). With this pull request tmpfs will
     be able to support a limited number of user xattrs.

     This is accompanied by a fix (see below) to limit persistent simple
     xattr allocations.

   - Add support for stable directory offsets. Currently tmpfs relies on
     the libfs provided cursor-based mechanism for readdir. This causes
     issues when a tmpfs filesystem is exported via NFS.

     NFS clients do not open directories. Instead, each server-side
     readdir operation opens the directory, reads it, and then closes
     it. Since the cursor state for that directory is associated with
     the opened file it is discarded after each readdir operation. Such
     directory offsets are not just cached by NFS clients but also
     various userspace libraries based on these clients.

     As it stands there is no way to invalidate the caches when
     directory offsets have changed and the whole application depends on
     unchanging directory offsets.

     At LSFMM we discussed how to solve this problem and decided to
     support stable directory offsets. libfs now allows filesystems like
     tmpfs to use an xarrary to map a directory offset to a dentry. This
     mechanism is currently only used by tmpfs but can be supported by
     others as well.

  Fixes
  =====

   - Change persistent simple xattrs allocations in libfs from
     GFP_KERNEL to GPF_KERNEL_ACCOUNT so they're subject to memory
     cgroup limits. Since this is a change to libfs it affects both
     tmpfs and kernfs.

   - Correctly verify {g,u}id mount options.

     A new filesystem context is created via fsopen() which records the
     namespace that becomes the owning namespace of the superblock when
     fsconfig(FSCONFIG_CMD_CREATE) is called for filesystems that are
     mountable in namespaces. However, fsconfig() calls can occur in a
     namespace different from the namespace where fsopen() has been
     called.

     Currently, when fsconfig() is called to set {g,u}id mount options
     the requested {g,u}id is mapped into a k{g,u}id according to the
     namespace where fsconfig() was called from. The resulting k{g,u}id
     is not guaranteed to be resolvable in the namespace of the
     filesystem (the one that fsopen() was called in).

     This means it's possible for an unprivileged user to create files
     owned by any group in a tmpfs mount since it's possible to set the
     setid bits on the tmpfs directory.

     The contract for {g,u}id mount options and {g,u}id values in
     general set from userspace has always been that they are translated
     according to the caller's idmapping. In so far, tmpfs has been
     doing the correct thing. But since tmpfs is mountable in
     unprivileged contexts it is also necessary to verify that the
     resulting {k,g}uid is representable in the namespace of the
     superblock to avoid such bugs.

     The new mount api's cross-namespace delegation abilities are
     already widely used. Having talked to a bunch of userspace this is
     the most faithful solution with minimal regression risks"

* tag 'v6.6-vfs.tmpfs' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
  tmpfs,xattr: GFP_KERNEL_ACCOUNT for simple xattrs
  mm: invalidation check mapping before folio_contains
  tmpfs: trivial support for direct IO
  tmpfs,xattr: enable limited user extended attributes
  tmpfs: track free_ispace instead of free_inodes
  xattr: simple_xattr_set() return old_xattr to be freed
  tmpfs: verify {g,u}id mount options correctly
  shmem: move spinlock into shmem_recalc_inode() to fix quota support
  libfs: Remove parent dentry locking in offset_iterate_dir()
  libfs: Add a lock class for the offset map's xa_lock
  shmem: stable directory offsets
  shmem: Refactor shmem_symlink()
  libfs: Add directory operations for stable offsets
  shmem: fix quota lock nesting in huge hole handling
  shmem: Add default quota limit mount options
  shmem: quota support
  shmem: prepare shmem quota infrastructure
  quota: Check presence of quota operation structures instead of ->quota_read and ->quota_write callbacks
  shmem: make shmem_get_inode() return ERR_PTR instead of NULL
  shmem: make shmem_inode_acct_block() return error
2023-08-28 09:55:25 -07:00
Eric Biggers
af494af385 libfs: remove redundant checks of s_encoding
Now that neither ext4 nor f2fs allows inodes with the casefold flag to
be instantiated when unsupported, it's unnecessary to repeatedly check
for support later on during random filesystem operations.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Link: https://lore.kernel.org/r/20230814182903.37267-4-ebiggers@kernel.org
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2023-08-27 11:27:13 -04:00
Matthew Wilcox (Oracle)
5522d9f7b2 libfs: Convert simple_write_begin and simple_write_end to use a folio
Remove a number of implicit calls to compound_head() and various calls
to compatibility functions.  This is not sufficient to enable support
for large folios; generic_perform_write() must be converted first.

Signed-off-by: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Message-Id: <20230821141322.2535459-1-willy@infradead.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-08-21 17:23:57 +02:00
Chuck Lever
2be4f05af7 libfs: Remove parent dentry locking in offset_iterate_dir()
Since offset_iterate_dir() does not walk the parent's d_subdir list
nor does it manipulate the parent's d_child, there doesn't seem to
be a reason to hold the parent's d_lock. The offset_ctx's xarray can
be sufficiently protected with just the RCU read lock.

Flame graph data captured during the git regression run shows a
20% reduction in CPU cycles consumed in offset_find_next().

Reported-by: kernel test robot <oliver.sang@intel.com>
Closes: https://lore.kernel.org/oe-lkp/202307171640.e299f8d5-oliver.sang@intel.com
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Message-Id: <169030957098.157536.9938425508695693348.stgit@manet.1015granger.net>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-08-09 09:15:41 +02:00
Chuck Lever
bbaef7973d libfs: Add a lock class for the offset map's xa_lock
Tie the dynamically-allocated xarray locks into a single class so
contention on the directory offset xarrays can be observed.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Message-Id: <169020933088.160441.9405180953116076087.stgit@manet.1015granger.net>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-08-09 09:15:41 +02:00
Chuck Lever
6faddda69f libfs: Add directory operations for stable offsets
Create a vector of directory operations in fs/libfs.c that handles
directory seeks and readdir via stable offsets instead of the
current cursor-based mechanism.

For the moment these are unused.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Message-Id: <168814732984.530310.11190772066786107220.stgit@manet.1015granger.net>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-08-09 09:15:40 +02:00
Jeff Layton
0d72b92883 fs: pass the request_mask to generic_fillattr
generic_fillattr just fills in the entire stat struct indiscriminately
today, copying data from the inode. There is at least one attribute
(STATX_CHANGE_COOKIE) that can have side effects when it is reported,
and we're looking at adding more with the addition of multigrain
timestamps.

Add a request_mask argument to generic_fillattr and have most callers
just pass in the value that is passed to getattr. Have other callers
(e.g. ksmbd) just pass in STATX_BASIC_STATS. Also move the setting of
STATX_CHANGE_COOKIE into generic_fillattr.

Acked-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Reviewed-by: Xiubo Li <xiubli@redhat.com>
Reviewed-by: "Paulo Alcantara (SUSE)" <pc@manguebit.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Message-Id: <20230807-mgctime-v7-2-d1dec143a704@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-08-09 08:56:36 +02:00
Jeff Layton
f7f438589f kernfs: convert to ctime accessor functions
In later patches, we're going to change how the inode's ctime field is
used. Switch to using accessor functions instead of raw accesses of
inode->i_ctime.

Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Message-Id: <20230705190309.579783-54-jlayton@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-07-24 10:30:01 +02:00
Luca Vizzarro
ed5f17f66e fs: Pass argument to fcntl_setlease as int
The interface for fcntl expects the argument passed for the command
F_SETLEASE to be of type int. The current code wrongly treats it as
a long. In order to avoid access to undefined bits, we should explicitly
cast the argument to int.

Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Jeff Layton <jlayton@kernel.org>
Cc: Chuck Lever <chuck.lever@oracle.com>
Cc: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: Anna Schumaker <anna@kernel.org>
Cc: Kevin Brodsky <Kevin.Brodsky@arm.com>
Cc: Vincenzo Frascino <Vincenzo.Frascino@arm.com>
Cc: Szabolcs Nagy <Szabolcs.Nagy@arm.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: David Laight <David.Laight@ACULAB.com>
Cc: Mark Rutland <Mark.Rutland@arm.com>
Cc: linux-fsdevel@vger.kernel.org
Cc: linux-cifs@vger.kernel.org
Cc: linux-nfs@vger.kernel.org
Cc: linux-morello@op-lists.linaro.org
Signed-off-by: Luca Vizzarro <Luca.Vizzarro@arm.com>
Message-Id: <20230414152459.816046-3-Luca.Vizzarro@arm.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-07-10 14:36:11 +02:00
Jeff Layton
0c4767923e fs: new helper: simple_rename_timestamp
A rename potentially involves updating 4 different inode timestamps. Add
a function that handles the details sanely, and convert the libfs.c
callers to use it.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Message-Id: <20230705185812.579118-3-jlayton@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-07-10 10:08:09 +02:00
Christoph Hellwig
44fff0fa08 fs: factor out a direct_write_fallback helper
Add a helper dealing with handling the syncing of a buffered write
fallback for direct I/O.

Link: https://lkml.kernel.org/r/20230601145904.1385409-10-hch@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Miklos Szeredi <mszeredi@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andreas Gruenbacher <agruenba@redhat.com>
Cc: Anna Schumaker <anna@kernel.org>
Cc: Chao Yu <chao@kernel.org>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Ilya Dryomov <idryomov@gmail.com>
Cc: Jaegeuk Kim <jaegeuk@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Miklos Szeredi <miklos@szeredi.hu>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: Xiubo Li <xiubli@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-06-09 16:25:53 -07:00
Jeff Layton
364595a685
fs: consolidate duplicate dt_type helpers
There are three copies of the same dt_type helper sprinkled around the
tree. Convert them to use the common fs_umode_to_dtype function instead,
which has the added advantage of properly returning DT_UNKNOWN when
given a mode that contains an unrecognized type.

Cc: Chuck Lever <chuck.lever@oracle.com>
Cc: Phillip Potter <phil@philpotter.co.uk>
Suggested-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Christian Brauner <brauner@kernel.org>
Message-Id: <20230330104144.75547-1-jlayton@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-04-03 09:23:54 +02:00