| Age | Commit message (Collapse) | Author | Files | Lines |
|---|
|
maple_tree insertions can fail if we are seriously short on memory;
simple_offset_rename() does not recover well if it runs into that.
The same goes for simple_offset_rename_exchange().
Moreover, shmem_whiteout() expects that if it succeeds, the caller will
progress to d_move(), i.e. that shmem_rename2() won't fail past the
successful call of shmem_whiteout().
Not hard to fix, fortunately - mtree_store() can't fail if the index we
are trying to store into is already present in the tree as a singleton.
For simple_offset_rename_exchange() that's enough - we just need to be
careful about the order of operations.
For simple_offset_rename() solution is to preinsert the target into the
tree for new_dir; the rest can be done without any potentially failing
operations.
That preinsertion has to be done in shmem_rename2() rather than in
simple_offset_rename() itself - otherwise we'd need to deal with the
possibility of failure after successful shmem_whiteout().
Fixes: a2e459555c5f ("shmem: stable directory offsets")
Reviewed-by: Christian Brauner <brauner@kernel.org>
Reviewed-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull persistent dentry infrastructure and conversion from Al Viro:
"Some filesystems use a kinda-sorta controlled dentry refcount leak to
pin dentries of created objects in dcache (and undo it when removing
those). A reference is grabbed and not released, but it's not actually
_stored_ anywhere.
That works, but it's hard to follow and verify; among other things, we
have no way to tell _which_ of the increments is intended to be an
unpaired one. Worse, on removal we need to decide whether the
reference had already been dropped, which can be non-trivial if that
removal is on umount and we need to figure out if this dentry is
pinned due to e.g. unlink() not done. Usually that is handled by using
kill_litter_super() as ->kill_sb(), but there are open-coded special
cases of the same (consider e.g. /proc/self).
Things get simpler if we introduce a new dentry flag
(DCACHE_PERSISTENT) marking those "leaked" dentries. Having it set
claims responsibility for +1 in refcount.
The end result this series is aiming for:
- get these unbalanced dget() and dput() replaced with new primitives
that would, in addition to adjusting refcount, set and clear
persistency flag.
- instead of having kill_litter_super() mess with removing the
remaining "leaked" references (e.g. for all tmpfs files that hadn't
been removed prior to umount), have the regular
shrink_dcache_for_umount() strip DCACHE_PERSISTENT of all dentries,
dropping the corresponding reference if it had been set. After that
kill_litter_super() becomes an equivalent of kill_anon_super().
Doing that in a single step is not feasible - it would affect too many
places in too many filesystems. It has to be split into a series.
This work has really started early in 2024; quite a few preliminary
pieces have already gone into mainline. This chunk is finally getting
to the meat of that stuff - infrastructure and most of the conversions
to it.
Some pieces are still sitting in the local branches, but the bulk of
that stuff is here"
* tag 'pull-persistency' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (54 commits)
d_make_discardable(): warn if given a non-persistent dentry
kill securityfs_recursive_remove()
convert securityfs
get rid of kill_litter_super()
convert rust_binderfs
convert nfsctl
convert rpc_pipefs
convert hypfs
hypfs: swich hypfs_create_u64() to returning int
hypfs: switch hypfs_create_str() to returning int
hypfs: don't pin dentries twice
convert gadgetfs
gadgetfs: switch to simple_remove_by_name()
convert functionfs
functionfs: switch to simple_remove_by_name()
functionfs: fix the open/removal races
functionfs: need to cancel ->reset_work in ->kill_sb()
functionfs: don't bother with ffs->ref in ffs_data_{opened,closed}()
functionfs: don't abuse ffs_data_closed() on fs shutdown
convert selinuxfs
...
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs
Pull directory locking updates from Christian Brauner:
"This contains the work to add centralized APIs for directory locking
operations.
This series is part of a larger effort to change directory operation
locking to allow multiple concurrent operations in a directory. The
ultimate goal is to lock the target dentry(s) rather than the whole
parent directory.
To help with changing the locking protocol, this series centralizes
locking and lookup in new helper functions. The helpers establish a
pattern where it is the dentry that is being locked and unlocked
(currently the lock is held on dentry->d_parent->d_inode, but that can
change in the future).
This also changes vfs_mkdir() to unlock the parent on failure, as well
as dput()ing the dentry. This allows end_creating() to only require
the target dentry (which may be IS_ERR() after vfs_mkdir()), not the
parent"
* tag 'vfs-6.19-rc1.directory.locking' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
nfsd: fix end_creating() conversion
VFS: introduce end_creating_keep()
VFS: change vfs_mkdir() to unlock on failure.
ecryptfs: use new start_creating/start_removing APIs
Add start_renaming_two_dentries()
VFS/ovl/smb: introduce start_renaming_dentry()
VFS/nfsd/ovl: introduce start_renaming() and end_renaming()
VFS: add start_creating_killable() and start_removing_killable()
VFS: introduce start_removing_dentry()
smb/server: use end_removing_noperm for for target of smb2_create_link()
VFS: introduce start_creating_noperm() and start_removing_noperm()
VFS/nfsd/cachefiles/ovl: introduce start_removing() and end_removing()
VFS/nfsd/cachefiles/ovl: add start_creating() and end_creating()
VFS: tidy up do_unlinkat()
VFS: introduce start_dirop() and end_dirop()
debugfs: rename end_creating() to debugfs_end_creating()
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs
Pull namespace updates from Christian Brauner:
"This contains substantial namespace infrastructure changes including a new
system call, active reference counting, and extensive header cleanups.
The branch depends on the shared kbuild branch for -fms-extensions support.
Features:
- listns() system call
Add a new listns() system call that allows userspace to iterate
through namespaces in the system. This provides a programmatic
interface to discover and inspect namespaces, addressing
longstanding limitations:
Currently, there is no direct way for userspace to enumerate
namespaces. Applications must resort to scanning /proc/*/ns/ across
all processes, which is:
- Inefficient - requires iterating over all processes
- Incomplete - misses namespaces not attached to any running
process but kept alive by file descriptors, bind mounts, or
parent references
- Permission-heavy - requires access to /proc for many processes
- No ordering or ownership information
- No filtering per namespace type
The listns() system call solves these problems:
ssize_t listns(const struct ns_id_req *req, u64 *ns_ids,
size_t nr_ns_ids, unsigned int flags);
struct ns_id_req {
__u32 size;
__u32 spare;
__u64 ns_id;
struct /* listns */ {
__u32 ns_type;
__u32 spare2;
__u64 user_ns_id;
};
};
Features include:
- Pagination support for large namespace sets
- Filtering by namespace type (MNT_NS, NET_NS, USER_NS, etc.)
- Filtering by owning user namespace
- Permission checks respecting namespace isolation
- Active Reference Counting
Introduce an active reference count that tracks namespace
visibility to userspace. A namespace is visible in the following
cases:
- The namespace is in use by a task
- The namespace is persisted through a VFS object (namespace file
descriptor or bind-mount)
- The namespace is a hierarchical type and is the parent of child
namespaces
The active reference count does not regulate lifetime (that's still
done by the normal reference count) - it only regulates visibility
to namespace file handles and listns().
This prevents resurrection of namespaces that are pinned only for
internal kernel reasons (e.g., user namespaces held by
file->f_cred, lazy TLB references on idle CPUs, etc.) which should
not be accessible via (1)-(3).
- Unified Namespace Tree
Introduce a unified tree structure for all namespaces with:
- Fixed IDs assigned to initial namespaces
- Lookup based solely on inode number
- Maintained list of owned namespaces per user namespace
- Simplified rbtree comparison helpers
Cleanups
- Header Reorganization:
- Move namespace types into separate header (ns_common_types.h)
- Decouple nstree from ns_common header
- Move nstree types into separate header
- Switch to new ns_tree_{node,root} structures with helper functions
- Use guards for ns_tree_lock
- Initial Namespace Reference Count Optimization
- Make all reference counts on initial namespaces a nop to avoid
pointless cacheline ping-pong for namespaces that can never go
away
- Drop custom reference count initialization for initial namespaces
- Add NS_COMMON_INIT() macro and use it for all namespaces
- pid: rely on common reference count behavior
- Miscellaneous Cleanups
- Rename exit_task_namespaces() to exit_nsproxy_namespaces()
- Rename is_initial_namespace() and make argument const
- Use boolean to indicate anonymous mount namespace
- Simplify owner list iteration in nstree
- nsfs: raise SB_I_NODEV, SB_I_NOEXEC, and DCACHE_DONTCACHE explicitly
- nsfs: use inode_just_drop()
- pidfs: raise DCACHE_DONTCACHE explicitly
- pidfs: simplify PIDFD_GET__NAMESPACE ioctls
- libfs: allow to specify s_d_flags
- cgroup: add cgroup namespace to tree after owner is set
- nsproxy: fix free_nsproxy() and simplify create_new_namespaces()
Fixes:
- setns(pidfd, ...) race condition
Fix a subtle race when using pidfds with setns(). When the target
task exits after prepare_nsset() but before commit_nsset(), the
namespace's active reference count might have been dropped. If
setns() then installs the namespaces, it would bump the active
reference count from zero without taking the required reference on
the owner namespace, leading to underflow when later decremented.
The fix resurrects the ownership chain if necessary - if the caller
succeeded in grabbing passive references, the setns() should
succeed even if the target task exits or gets reaped.
- Return EFAULT on put_user() error instead of success
- Make sure references are dropped outside of RCU lock (some
namespaces like mount namespace sleep when putting the last
reference)
- Don't skip active reference count initialization for network
namespace
- Add asserts for active refcount underflow
- Add asserts for initial namespace reference counts (both passive
and active)
- ipc: enable is_ns_init_id() assertions
- Fix kernel-doc comments for internal nstree functions
- Selftests
- 15 active reference count tests
- 9 listns() functionality tests
- 7 listns() permission tests
- 12 inactive namespace resurrection tests
- 3 threaded active reference count tests
- commit_creds() active reference tests
- Pagination and stress tests
- EFAULT handling test
- nsid tests fixes"
* tag 'namespace-6.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (103 commits)
pidfs: simplify PIDFD_GET_<type>_NAMESPACE ioctls
nstree: fix kernel-doc comments for internal functions
nsproxy: fix free_nsproxy() and simplify create_new_namespaces()
selftests/namespaces: fix nsid tests
ns: drop custom reference count initialization for initial namespaces
pid: rely on common reference count behavior
ns: add asserts for initial namespace active reference counts
ns: add asserts for initial namespace reference counts
ns: make all reference counts on initial namespace a nop
ipc: enable is_ns_init_id() assertions
fs: use boolean to indicate anonymous mount namespace
ns: rename is_initial_namespace()
ns: make is_initial_namespace() argument const
nstree: use guards for ns_tree_lock
nstree: simplify owner list iteration
nstree: switch to new structures
nstree: add helper to operate on struct ns_tree_{node,root}
nstree: move nstree types into separate header
nstree: decouple from ns_common header
ns: move namespace types into separate header
...
|
|
At this point there are very few call chains that might lead to
d_make_discardable() on a dentry that hadn't been made persistent:
calls of simple_unlink() and simple_rmdir() in configfs and
apparmorfs.
Both filesystems do pin (part of) their contents in dcache, but
they are currently playing very unusual games with that. Converting
them to more usual patterns might be possible, but it's definitely
going to be a long series of changes in both cases.
For now the easiest solution is to have both stop using simple_unlink()
and simple_rmdir() - that allows to make d_make_discardable() warn
when given a non-persistent dentry.
Rather than giving them full-blown private copies (with calls of
d_make_discardable() replaced with dput()), let's pull the parts of
simple_unlink() and simple_rmdir() that deal with timestamps and link
counts into separate helpers (__simple_unlink() and __simple_rmdir()
resp.) and have those used by configfs and apparmorfs.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
|
|
Note that simple_unlink() et.al. are used by many filesystems; for now
they can not assume that persistency mark will have been set back
when the object got created. Once all conversions are done we'll
have them complain if called for something that had not been marked
persistent.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
|
|
should be paired with simple_start_creating() - unlocks parent and
drops dentry reference.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
|
|
simple_recursive_removal(), but instead of victim dentry it takes
parent + name.
Used to be open-coded in fs/fuse/control.c, but there's no need to expose
the guts of that thing there and there are other potential users, so
let's lift it into libfs...
Acked-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
|
|
The fact that directory operations (create,remove,rename) are protected
by a lock on the parent is known widely throughout the kernel.
In order to change this - to instead lock the target dentry - it is
best to centralise this knowledge so it can be changed in one place.
This patch introduces start_dirop() which is local to VFS code.
It performs the required locking for create and remove. Rename
will be handled separately.
Various functions with names like start_creating() or start_removing_path(),
some of which already exist, will export this functionality beyond the VFS.
end_dirop() is the partner of start_dirop(). It drops the lock and
releases the reference on the dentry.
It *is* exported so that various end_creating etc functions can be inline.
As vfs_mkdir() drops the dentry on error we cannot use end_dirop() as
that won't unlock when the dentry IS_ERR(). For now we need an explicit
unlock when dentry IS_ERR(). I hope to change vfs_mkdir() to unlock
when it drops a dentry so that explicit unlock can go away.
end_dirop() can always be called on the result of start_dirop(), but not
after vfs_mkdir(). After a vfs_mkdir() we still may need the explicit
unlock as seen in end_creating_path().
As well as adding start_dirop() and end_dirop()
this patch uses them in:
- simple_start_creating (which requires sharing lookup_noperm_common()
with libfs.c)
- start_removing_path / start_removing_user_path_at
- filename_create / end_creating_path()
- do_rmdir(), do_unlinkat()
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: NeilBrown <neil@brown.name>
Link: https://patch.msgid.link/20251113002050.676694-3-neilb@ownmail.net
Tested-by: syzbot@syzkaller.appspotmail.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
|
|
Make it possible for pseudo filesystems to specify default dentry flags.
Link: https://patch.msgid.link/20251029-work-namespace-nstree-listns-v4-1-2e6f823ebdc0@kernel.org
Tested-by: syzbot@syzkaller.appspotmail.com
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
|
|
All places were patched by coccinelle with the default expecting that
->i_lock is held, afterwards entries got fixed up by hand to use
unlocked variants as needed.
The script:
@@
expression inode, flags;
@@
- inode->i_state & flags
+ inode_state_read(inode) & flags
@@
expression inode, flags;
@@
- inode->i_state &= ~flags
+ inode_state_clear(inode, flags)
@@
expression inode, flag1, flag2;
@@
- inode->i_state &= ~flag1 & ~flag2
+ inode_state_clear(inode, flag1 | flag2)
@@
expression inode, flags;
@@
- inode->i_state |= flags
+ inode_state_set(inode, flags)
@@
expression inode, flags;
@@
- inode->i_state = flags
+ inode_state_assign(inode, flags)
@@
expression inode, flags;
@@
- flags = inode->i_state
+ flags = inode_state_read(inode)
@@
expression inode, flags;
@@
- READ_ONCE(inode->i_state) & flags
+ inode_state_read(inode) & flags
Signed-off-by: Mateusz Guzik <mjguzik@gmail.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs
Pull pidfs updates from Christian Brauner:
- persistent info
Persist exit and coredump information independent of whether anyone
currently holds a pidfd for the struct pid.
The current scheme allocated pidfs dentries on-demand repeatedly.
This scheme is reaching it's limits as it makes it impossible to pin
information that needs to be available after the task has exited or
coredumped and that should not be lost simply because the pidfd got
closed temporarily. The next opener should still see the stashed
information.
This is also a prerequisite for supporting extended attributes on
pidfds to allow attaching meta information to them.
If someone opens a pidfd for a struct pid a pidfs dentry is allocated
and stashed in pid->stashed. Once the last pidfd for the struct pid
is closed the pidfs dentry is released and removed from pid->stashed.
So if 10 callers create a pidfs dentry for the same struct pid
sequentially, i.e., each closing the pidfd before the other creates a
new one then a new pidfs dentry is allocated every time.
Because multiple tasks acquiring and releasing a pidfd for the same
struct pid can race with each another a task may still find a valid
pidfs entry from the previous task in pid->stashed and reuse it. Or
it might find a dead dentry in there and fail to reuse it and so
stashes a new pidfs dentry. Multiple tasks may race to stash a new
pidfs dentry but only one will succeed, the other ones will put their
dentry.
The current scheme aims to ensure that a pidfs dentry for a struct
pid can only be created if the task is still alive or if a pidfs
dentry already existed before the task was reaped and so exit
information has been was stashed in the pidfs inode.
That's great except that it's buggy. If a pidfs dentry is stashed in
pid->stashed after pidfs_exit() but before __unhash_process() is
called we will return a pidfd for a reaped task without exit
information being available.
The pidfds_pid_valid() check does not guard against this race as it
doens't sync at all with pidfs_exit(). The pid_has_task() check might
be successful simply because we're before __unhash_process() but
after pidfs_exit().
Introduce a new scheme where the lifetime of information associated
with a pidfs entry (coredump and exit information) isn't bound to the
lifetime of the pidfs inode but the struct pid itself.
The first time a pidfs dentry is allocated for a struct pid a struct
pidfs_attr will be allocated which will be used to store exit and
coredump information.
If all pidfs for the pidfs dentry are closed the dentry and inode can
be cleaned up but the struct pidfs_attr will stick until the struct
pid itself is freed. This will ensure minimal memory usage while
persisting relevant information.
The new scheme has various advantages. First, it allows to close the
race where we end up handing out a pidfd for a reaped task for which
no exit information is available. Second, it minimizes memory usage.
Third, it allows to remove complex lifetime tracking via dentries
when registering a struct pid with pidfs. There's no need to get or
put a reference. Instead, the lifetime of exit and coredump
information associated with a struct pid is bound to the lifetime of
struct pid itself.
- extended attributes
Now that we have a way to persist information for pidfs dentries we
can start supporting extended attributes on pidfds. This will allow
userspace to attach meta information to tasks.
One natural extension would be to introduce a custom pidfs.* extended
attribute space and allow for the inheritance of extended attributes
across fork() and exec().
The first simple scheme will allow privileged userspace to set
trusted extended attributes on pidfs inodes.
- Allow autonomous pidfs file handles
Various filesystems such as pidfs and drm support opening file
handles without having to require a file descriptor to identify the
filesystem. The filesystem are global single instances and can be
trivially identified solely on the information encoded in the file
handle.
This makes it possible to not have to keep or acquire a sentinal file
descriptor just to pass it to open_by_handle_at() to identify the
filesystem. That's especially useful when such sentinel file
descriptor cannot or should not be acquired.
For pidfs this means a file handle can function as full replacement
for storing a pid in a file. Instead a file handle can be stored and
reopened purely based on the file handle.
Such autonomous file handles can be opened with or without specifying
a a file descriptor. If no proper file descriptor is used the
FD_PIDFS_ROOT sentinel must be passed. This allows us to define
further special negative fd sentinels in the future.
Userspace can trivially test for support by trying to open the file
handle with an invalid file descriptor.
- Allow pidfds for reaped tasks with SCM_PIDFD messages
This is a logical continuation of the earlier work to create pidfds
for reaped tasks through the SO_PEERPIDFD socket option merged in
923ea4d4482b ("Merge patch series "net, pidfs: enable handing out
pidfds for reaped sk->sk_peer_pid"").
- Two minor fixes:
* Fold fs_struct->{lock,seq} into a seqlock
* Don't bother with path_{get,put}() in unix_open_file()
* tag 'vfs-6.17-rc1.pidfs' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (37 commits)
don't bother with path_get()/path_put() in unix_open_file()
fold fs_struct->{lock,seq} into a seqlock
selftests: net: extend SCM_PIDFD test to cover stale pidfds
af_unix: enable handing out pidfds for reaped tasks in SCM_PIDFD
af_unix: stash pidfs dentry when needed
af_unix/scm: fix whitespace errors
af_unix: introduce and use scm_replace_pid() helper
af_unix: introduce unix_skb_to_scm helper
af_unix: rework unix_maybe_add_creds() to allow sleep
selftests/pidfd: decode pidfd file handles withou having to specify an fd
fhandle, pidfs: support open_by_handle_at() purely based on file handle
uapi/fcntl: add FD_PIDFS_ROOT
uapi/fcntl: add FD_INVALID
fcntl/pidfd: redefine PIDFD_SELF_THREAD_GROUP
uapi/fcntl: mark range as reserved
fhandle: reflow get_path_anchor()
pidfs: add pidfs_root_path() helper
fhandle: rename to get_path_anchor()
fhandle: hoist copy_from_user() above get_path_from_fd()
fhandle: raise FILEID_IS_DIR in handle_type
...
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs
Pull misc VFS updates from Christian Brauner:
"This contains the usual selections of misc updates for this cycle.
Features:
- Add ext4 IOCB_DONTCACHE support
This refactors the address_space_operations write_begin() and
write_end() callbacks to take const struct kiocb * as their first
argument, allowing IOCB flags such as IOCB_DONTCACHE to propagate
to the filesystem's buffered I/O path.
Ext4 is updated to implement handling of the IOCB_DONTCACHE flag
and advertises support via the FOP_DONTCACHE file operation flag.
Additionally, the i915 driver's shmem write paths are updated to
bypass the legacy write_begin/write_end interface in favor of
directly calling write_iter() with a constructed synchronous kiocb.
Another i915 change replaces a manual write loop with
kernel_write() during GEM shmem object creation.
Cleanups:
- don't duplicate vfs_open() in kernel_file_open()
- proc_fd_getattr(): don't bother with S_ISDIR() check
- fs/ecryptfs: replace snprintf with sysfs_emit in show function
- vfs: Remove unnecessary list_for_each_entry_safe() from
evict_inodes()
- filelock: add new locks_wake_up_waiter() helper
- fs: Remove three arguments from block_write_end()
- VFS: change old_dir and new_dir in struct renamedata to dentrys
- netfs: Remove unused declaration netfs_queue_write_request()
Fixes:
- eventpoll: Fix semi-unbounded recursion
- eventpoll: fix sphinx documentation build warning
- fs/read_write: Fix spelling typo
- fs: annotate data race between poll_schedule_timeout() and
pollwake()
- fs/pipe: set FMODE_NOWAIT in create_pipe_files()
- docs/vfs: update references to i_mutex to i_rwsem
- fs/buffer: remove comment about hard sectorsize
- fs/buffer: remove the min and max limit checks in __getblk_slow()
- fs/libfs: don't assume blocksize <= PAGE_SIZE in
generic_check_addressable
- fs_context: fix parameter name in infofc() macro
- fs: Prevent file descriptor table allocations exceeding INT_MAX"
* tag 'vfs-6.17-rc1.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (24 commits)
netfs: Remove unused declaration netfs_queue_write_request()
eventpoll: fix sphinx documentation build warning
ext4: support uncached buffered I/O
mm/pagemap: add write_begin_get_folio() helper function
fs: change write_begin/write_end interface to take struct kiocb *
drm/i915: Refactor shmem_pwrite() to use kiocb and write_iter
drm/i915: Use kernel_write() in shmem object create
eventpoll: Fix semi-unbounded recursion
vfs: Remove unnecessary list_for_each_entry_safe() from evict_inodes()
fs/libfs: don't assume blocksize <= PAGE_SIZE in generic_check_addressable
fs/buffer: remove the min and max limit checks in __getblk_slow()
fs: Prevent file descriptor table allocations exceeding INT_MAX
fs: Remove three arguments from block_write_end()
fs/ecryptfs: replace snprintf with sysfs_emit in show function
fs: annotate suspected data race between poll_schedule_timeout() and pollwake()
docs/vfs: update references to i_mutex to i_rwsem
fs/buffer: remove comment about hard sectorsize
fs_context: fix parameter name in infofc() macro
VFS: change old_dir and new_dir in struct renamedata to dentrys
proc_fd_getattr(): don't bother with S_ISDIR() check
...
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull rpc_pipefs updates from Al Viro:
"Massage rpc_pipefs to use saner primitives and clean up the APIs
provided to the rest of the kernel"
* tag 'pull-rpc_pipefs' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
rpc_create_client_dir(): return 0 or -E...
rpc_create_client_dir(): don't bother with rpc_populate()
rpc_new_dir(): the last argument is always NULL
rpc_pipe: expand the calls of rpc_mkdir_populate()
rpc_gssd_dummy_populate(): don't bother with rpc_populate()
rpc_mkpipe_dentry(): switch to simple_start_creating()
rpc_pipe: saner primitive for creating regular files
rpc_pipe: saner primitive for creating subdirectories
rpc_pipe: don't overdo directory locking
rpc_mkpipe_dentry(): saner calling conventions
rpc_unlink(): saner calling conventions
rpc_populate(): lift cleanup into callers
rpc_unlink(): use simple_recursive_removal()
rpc_{rmdir_,}depopulate(): use simple_recursive_removal() instead
rpc_pipe: clean failure exits in fill_super
new helper: simple_start_creating()
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull simple_recursive_removal() update from Al Viro:
"Removing subtrees of kernel filesystems is done in quite a few places;
unfortunately, it's easy to get wrong. A number of open-coded attempts
are out there, with varying amount of bogosities.
simple_recursive_removal() had been introduced for doing that with all
precautions needed; it does an equivalent of rm -rf, with sufficient
locking, eviction of anything mounted on top of the subtree, etc.
This series converts a bunch of open-coded instances to using that"
* tag 'pull-simple_recursive_removal' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
functionfs, gadgetfs: use simple_recursive_removal()
kill binderfs_remove_file()
fuse_ctl: use simple_recursive_removal()
pstore: switch to locked_recursive_removal()
binfmt_misc: switch to locked_recursive_removal()
spufs: switch to locked_recursive_removal()
add locked_recursive_removal()
better lockdep annotations for simple_recursive_removal()
simple_recursive_removal(): saner interaction with fsnotify
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull dentry d_flags updates from Al Viro:
"The current exclusion rules for dentry->d_flags stores are rather
unpleasant. The basic rules are simple:
- stores to dentry->d_flags are OK under dentry->d_lock
- stores to dentry->d_flags are OK in the dentry constructor, before
becomes potentially visible to other threads
Unfortunately, there's a couple of exceptions to that, and that's
where the headache comes from.
The main PITA comes from d_set_d_op(); that primitive sets ->d_op of
dentry and adjusts the flags that correspond to presence of individual
methods. It's very easy to misuse; existing uses _are_ safe, but proof
of correctness is brittle.
Use in __d_alloc() is safe (we are within a constructor), but we might
as well precalculate the initial value of 'd_flags' when we set the
default ->d_op for given superblock and set 'd_flags' directly instead
of messing with that helper.
The reasons why other uses are safe are bloody convoluted; I'm not
going to reproduce it here. See [1] for gory details, if you care. The
critical part is using d_set_d_op() only just prior to
d_splice_alias(), which makes a combination of d_splice_alias() with
setting ->d_op, etc a natural replacement primitive.
Better yet, if we go that way, it's easy to take setting ->d_op and
modifying 'd_flags' under ->d_lock, which eliminates the headache as
far as 'd_flags' exclusion rules are concerned. Other exceptions are
minor and easy to deal with.
What this series does:
- d_set_d_op() is no longer available; instead a new primitive
(d_splice_alias_ops()) is provided, equivalent to combination of
d_set_d_op() and d_splice_alias().
- new field of struct super_block - 's_d_flags'. This sets the
default value of 'd_flags' to be used when allocating dentries on
this filesystem.
- new primitive for setting 's_d_op': set_default_d_op(). This
replaces stores to 's_d_op' at mount time.
All in-tree filesystems converted; out-of-tree ones will get caught
by the compiler ('s_d_op' is renamed, so stores to it will be
caught). 's_d_flags' is set by the same primitive to match the
's_d_op'.
- a lot of filesystems had sb->s_d_op->d_delete equal to
always_delete_dentry; that is equivalent to setting
DCACHE_DONTCACHE in 'd_flags', so such filesystems can bloody well
set that bit in 's_d_flags' and drop 'd_delete()' from
dentry_operations.
In quite a few cases that results in empty dentry_operations, which
means that we can get rid of those.
- kill simple_dentry_operations - not needed anymore
- massage d_alloc_parallel() to get rid of the other exception wrt
'd_flags' stores - we can set DCACHE_PAR_LOOKUP as soon as we
allocate the new dentry; no need to delay that until we commit to
using the sucker.
As the result, 'd_flags' stores are all either under ->d_lock or done
before the dentry becomes visible in any shared data structures"
Link: https://lore.kernel.org/all/20250224010624.GT1977892@ZenIV/ [1]
* tag 'pull-dcache' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (21 commits)
configfs: use DCACHE_DONTCACHE
debugfs: use DCACHE_DONTCACHE
efivarfs: use DCACHE_DONTCACHE instead of always_delete_dentry()
9p: don't bother with always_delete_dentry
ramfs, hugetlbfs, mqueue: set DCACHE_DONTCACHE
kill simple_dentry_operations
devpts, sunrpc, hostfs: don't bother with ->d_op
shmem: no dentry retention past the refcount reaching zero
d_alloc_parallel(): set DCACHE_PAR_LOOKUP earlier
make d_set_d_op() static
simple_lookup(): just set DCACHE_DONTCACHE
tracefs: Add d_delete to remove negative dentries
set_default_d_op(): calculate the matching value for ->d_flags
correct the set of flags forbidden at d_set_d_op() time
split d_flags calculation out of d_set_d_op()
new helper: set_default_d_op()
fuse: no need for special dentry_operations for root dentry
switch procfs from d_set_d_op() to d_splice_alias_ops()
new helper: d_splice_alias_ops()
procfs: kill ->proc_dops
...
|
|
Change the address_space_operations callbacks write_begin() and
write_end() to take struct kiocb * as the first argument instead of
struct file *.
Update all affected function prototypes, implementations, call sites,
and related documentation across VFS, filesystems, and block layer.
Part of a series refactoring address_space_operations write_begin and
write_end callbacks to use struct kiocb for passing write context and
flags.
Signed-off-by: Taotao Chen <chentaotao@didiglobal.com>
Link: https://lore.kernel.org/20250716093559.217344-4-chentaotao@didiglobal.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
|
|
Since [1], it is possible for filesystems to have blocksize > PAGE_SIZE
of the system.
Remove the assumption and make the check generic for all blocksizes in
generic_check_addressable().
[1] https://lore.kernel.org/linux-xfs/20240822135018.1931258-1-kernel@pankajraghav.com/
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Pankaj Raghav <p.raghav@samsung.com>
Link: https://lore.kernel.org/20250630104018.213985-1-p.raghav@samsung.com
Reviewed-by: Zhang Yi <yi.zhang@huawei.com>
Reviewed-by: Baokun Li <libaokun1@huawei.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
|
|
Set the things up for kernel-initiated creation of object in
a tree-in-dcache filesystem. With respect to locking it's
an equivalent of filename_create() - we either get a negative
dentry with locked parent, or ERR_PTR() and no locks taken.
tracefs and debugfs had that open-coded as part of their
object creation machinery; switched to calling new helper.
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
|
|
simple_recursive_removal() assumes that parent is not locked and
locks it when it finally gets to removing the victim itself.
Usually that's what we want, but there are places where the
parent is *already* locked and we need it to stay that way.
In those cases simple_recursive_removal() would, of course,
deadlock, so we have to play racy games with unlocking/relocking
the parent around the call or open-code the entire thing.
A better solution is to provide a variant that expects to
be called with the parent already locked by the caller.
Parent should be locked with I_MUTEX_PARENT, to avoid false
positives from lockdep.
Reviewed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
|
|
We want a class that nests outside of I_MUTEX_NORMAL (for the sake of
callbacks that might want to lock the victim) and inside I_MUTEX_PARENT
(so that a variant of that could be used with parent of the victim
held locked by the caller).
In reality, simple_recursive_removal()
* never holds two locks at once
* holds the lock on parent of dentry passed to callback
* is used only on the trees with fixed topology, so the depths
are not changing.
So the locking order is actually fine.
AFAICS, the best solution is to assign I_MUTEX_CHILD to the locks
grabbed by that thing.
Reported-by: syzbot+169de184e9defe7fe709@syzkaller.appspotmail.com
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
|
|
Making anonymous inodes regular files comes with a lot of risk and
regression potential as evidenced by a recent hickup in io_uring. We're
better of continuing to not have them be regular files. Since we have
S_ANON_INODE we can port all of our assertions easily.
Link: https://lore.kernel.org/20250702-work-fixes-v1-1-ff76ea589e33@kernel.org
Fixes: cfd86ef7e8e7 ("anon_inode: use a proper mode internally")
Acked-by: Jens Axboe <axboe@kernel.dk>
Cc: stable@kernel.org
Reported-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Christian Brauner <brauner@kernel.org>
|
|
VFS has switched to i_rwsem for ten years now (9902af79c01a: parallel
lookups actual switch to rwsem), but the VFS documentation and comments
still has references to i_mutex.
Signed-off-by: Junxuan Liao <ljx@cs.wisc.edu>
Link: https://lore.kernel.org/72223729-5471-474a-af3c-f366691fba82@cs.wisc.edu
Signed-off-by: Christian Brauner <brauner@kernel.org>
|
|
Allow for S_IMMUTABLE to be stripped so that we can support xattrs.
Link: https://lore.kernel.org/20250618-work-pidfs-persistent-v2-10-98f3456fd552@kernel.org
Reviewed-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@canonical.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
|
|
Make it a littler easier to follow.
Link: https://lore.kernel.org/20250618-work-pidfs-persistent-v2-3-98f3456fd552@kernel.org
Reviewed-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@canonical.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
|
|
* Add a callback to struct stashed_operations so it's possible to
implement custom behavior for pidfs and allow for it to return errors.
* Teach stashed_dentry_get() to handle error pointers.
Link: https://lore.kernel.org/20250618-work-pidfs-persistent-v2-2-98f3456fd552@kernel.org
Reviewed-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@canonical.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
|
|
Make it match the real unlink(2)/rmdir(2) - notify *after* the
operation. And use fsnotify_delete() instead of messing with
fsnotify_unlink()/fsnotify_rmdir().
Currently the only caller that cares is the one in debugfs, and
there the order matching the normal syscalls makes more sense;
it'll get more serious for users introduced later in the series.
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Reviewed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
|
|
No users left and anything that wants it would be better off just
setting DCACHE_DONTCACHE in their ->s_d_flags.
Reviewed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
|
|
No need to mess with ->d_op at all. Note that ->d_delete that always
returns 1 is equivalent to having DCACHE_DONTCACHE in ->d_flags.
Later the same thing will be placed into ->s_d_flags of the filesystems
where we want that behaviour for all dentries; then the check in
simple_lookup() will at least get unlikely() slapped on it.
NOTE: there are only two filesystems where
* simple_lookup() might be called
* default ->d_op is non-NULL
* its ->d_delete() doesn't always return 1
If not for those, we could have simple_lookup() just set DCACHE_DONTCACHE
without even looking at ->d_op. Filesystems in question are btrfs
and tracefs; both have ->d_delete() returning 1 on anything fed to
simple_lookup(), so both would be fine with simple_lookup() setting
DCACHE_DONTCACHE regardless of ->d_op.
IOW, we might want to drop the check for ->d_op in simple_lookup();
it's definitely a separate story, though.
Reviewed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
|
|
... to be used instead of manually assigning to ->s_d_op.
All in-tree filesystem converted (and field itself is renamed,
so any out-of-tree ones in need of conversion will be caught
by compiler).
Reviewed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs
Pull vfs freezing updates from Christian Brauner:
"This contains various filesystem freezing related work for this cycle:
- Allow the power subsystem to support filesystem freeze for suspend
and hibernate.
Now all the pieces are in place to actually allow the power
subsystem to freeze/thaw filesystems during suspend/resume.
Filesystems are only frozen and thawed if the power subsystem does
actually own the freeze.
If the filesystem is already frozen by the time we've frozen all
userspace processes we don't care to freeze it again. That's
userspace's job once the process resumes. We only actually freeze
filesystems if we absolutely have to and we ignore other failures
to freeze.
We could bubble up errors and fail suspend/resume if the error
isn't EBUSY (aka it's already frozen) but I don't think that this
is worth it. Filesystem freezing during suspend/resume is
best-effort. If the user has 500 ext4 filesystems mounted and 4
fail to freeze for whatever reason then we simply skip them.
What we have now is already a big improvement and let's see how we
fare with it before making our lives even harder (and uglier) than
we have to.
- Allow efivars to support freeze and thaw
Allow efivarfs to partake to resync variable state during system
hibernation and suspend. Add freeze/thaw support.
This is a pretty straightforward implementation. We simply add
regular freeze/thaw support for both userspace and the kernel.
efivars is the first pseudofilesystem that adds support for
filesystem freezing and thawing.
The simplicity comes from the fact that we simply always resync
variable state after efivarfs has been frozen. It doesn't matter
whether that's because of suspend, userspace initiated freeze or
hibernation. Efivars is simple enough that it doesn't matter that
we walk all dentries. There are no directories and there aren't
insane amounts of entries and both freeze/thaw are already
heavy-handed operations. If userspace initiated a freeze/thaw cycle
they would need CAP_SYS_ADMIN in the initial user namespace (as
that's where efivarfs is mounted) so it can't be triggered by
random userspace. IOW, we really really don't care"
* tag 'vfs-6.16-rc1.super' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
f2fs: fix freezing filesystem during resize
kernfs: add warning about implementing freeze/thaw
efivarfs: support freeze/thaw
power: freeze filesystems during suspend/resume
libfs: export find_next_child()
super: add filesystem freezing helpers for suspend and hibernate
gfs2: pass through holder from the VFS for freeze/thaw
super: use common iterator (Part 2)
super: use a common iterator (Part 1)
super: skip dying superblocks early
super: simplify user_get_super()
super: remove pointless s_root checks
fs: allow all writers to be frozen
locking/percpu-rwsem: add freezable alternative to down_read
|
|
Export find_next_child() so it can be used by efivarfs.
Keep it internal for now. There's no reason to advertise this
kernel-wide.
Link: https://lore.kernel.org/r/20250331-work-freeze-v1-1-6dfbe8253b9f@kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
|
|
This makes it easy to detect proper anonymous inodes and to ensure that
we can detect them in codepaths such as readahead().
Readahead on anonymous inodes didn't work because they didn't have a
proper mode. Now that they have we need to retain EINVAL being returned
otherwise LTP will fail.
We also need to ensure that ioctls aren't simply fired like they are for
regular files so things like inotify inodes continue to correctly call
their own ioctl handlers as in [1].
Reported-by: Xilin Wu <sophon@radxa.com>
Link: https://lore.kernel.org/3A9139D5CD543962+89831381-31b9-4392-87ec-a84a5b3507d8@radxa.com [1]
Link: https://lore.kernel.org/7a1a7076-ff6b-4cb0-94e7-7218a0a44028@sirena.org.uk
Signed-off-by: Christian Brauner <brauner@kernel.org>
|
|
This allows the VFS to not trip over anonymous inodes and we can add
asserts based on the mode into the vfs. When we report it to userspace
we can simply hide the mode to avoid regressions. I've audited all
direct callers of alloc_anon_inode() and only secretmen overrides i_mode
and i_op inode operations but it already uses a regular file.
Link: https://lore.kernel.org/20250407-work-anon_inode-v1-1-53a44c20d |
