fuse_dentry_revalidate() may be called with a dentry that didn't had
->d_time initialised. The issue was found with KMSAN, where lookup_open()
calls __d_alloc(), followed by d_revalidate(), as shown below:
=====================================================
BUG: KMSAN: uninit-value in fuse_dentry_revalidate+0x150/0x13d0 fs/fuse/dir.c:394
fuse_dentry_revalidate+0x150/0x13d0 fs/fuse/dir.c:394
d_revalidate fs/namei.c:1030 [inline]
lookup_open fs/namei.c:4405 [inline]
open_last_lookups fs/namei.c:4583 [inline]
path_openat+0x1614/0x64c0 fs/namei.c:4827
do_file_open+0x2aa/0x680 fs/namei.c:4859
[...]
Uninit was created at:
slab_post_alloc_hook mm/slub.c:4466 [inline]
slab_alloc_node mm/slub.c:4788 [inline]
kmem_cache_alloc_lru_noprof+0x382/0x1280 mm/slub.c:4807
__d_alloc+0x55/0xa00 fs/dcache.c:1740
d_alloc_parallel+0x99/0x2740 fs/dcache.c:2604
lookup_open fs/namei.c:4398 [inline]
open_last_lookups fs/namei.c:4583 [inline]
path_openat+0x135f/0x64c0 fs/namei.c:4827
do_file_open+0x2aa/0x680 fs/namei.c:4859
[...]
=====================================================
Reported-by: syzbot+fdebb2dc960aa56c600a@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/all/69917e0d.050a0220.340abe.02e2.GAE@google.com
Fixes: 2396356a94 ("fuse: add more control over cache invalidation behaviour")
Signed-off-by: Luis Henriques <luis@igalia.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Remove the fuse_conn argument from function fuse_lookup_init() as it isn't
used since commit 21f621741a ("fuse: fix LOOKUP vs INIT compat
handling").
Signed-off-by: Luis Henriques <luis@igalia.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
This is the result of running the Coccinelle script from
scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to
avoid scalar types (which need careful case-by-case checking), and
instead replace kmalloc-family calls that allocate struct or union
object instances:
Single allocations: kmalloc(sizeof(TYPE), ...)
are replaced with: kmalloc_obj(TYPE, ...)
Array allocations: kmalloc_array(COUNT, sizeof(TYPE), ...)
are replaced with: kmalloc_objs(TYPE, COUNT, ...)
Flex array allocations: kmalloc(struct_size(PTR, FAM, COUNT), ...)
are replaced with: kmalloc_flex(*PTR, FAM, COUNT, ...)
(where TYPE may also be *VAR)
The resulting allocations no longer return "void *", instead returning
"TYPE *".
Signed-off-by: Kees Cook <kees@kernel.org>
Pull vfs lease updates from Christian Brauner:
"This contains updates for lease support to require filesystems to
explicitly opt-in to lease support
Currently kernel_setlease() falls through to generic_setlease() when a
a filesystem does not define ->setlease(), silently granting lease
support to every filesystem regardless of whether it is prepared for
it.
This is a poor default: most filesystems never intended to support
leases, and the silent fallthrough makes it impossible to distinguish
"supports leases" from "never thought about it".
This inverts the default. It adds explicit
.setlease = generic_setlease;
assignments to every in-tree filesystem that should retain lease
support, then changes kernel_setlease() to return -EINVAL when
->setlease is NULL.
With the new default in place, simple_nosetlease() is redundant and
is removed along with all references to it"
* tag 'vfs-7.0-rc1.leases' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (25 commits)
fuse: add setlease file operation
fs: remove simple_nosetlease()
filelock: default to returning -EINVAL when ->setlease operation is NULL
xfs: add setlease file operation
ufs: add setlease file operation
udf: add setlease file operation
tmpfs: add setlease file operation
squashfs: add setlease file operation
overlayfs: add setlease file operation
orangefs: add setlease file operation
ocfs2: add setlease file operation
ntfs3: add setlease file operation
nilfs2: add setlease file operation
jfs: add setlease file operation
jffs2: add setlease file operation
gfs2: add a setlease file operation
fat: add setlease file operation
f2fs: add setlease file operation
exfat: add setlease file operation
ext4: add setlease file operation
...
d_dispose_if_unused() may find the dentry with a positive refcount, in
which case it won't be put on the dispose list even though it has already
timed out.
"Reinstall" the d_delete() callback, which was optimized out in
fuse_dentry_settime(). This will result in the dentry being evicted as
soon as the refcount hits zero.
Fixes: ab84ad5973 ("fuse: new work queue to periodically invalidate expired dentries")
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Link: https://patch.msgid.link/20260114145344.468856-3-mszeredi@redhat.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
With a mix of include dependencies, the compiler warns that:
fs/fuse/dir.c:35:9: warning: ?HASH_BITS? redefined
35 | #define HASH_BITS 5
| ^~~~~~~~~
In file included from ./include/linux/io_uring_types.h:5,
from ./include/linux/bpf.h:34,
from ./include/linux/security.h:35,
from ./include/linux/fs_context.h:14,
from fs/fuse/dir.c:13:
./include/linux/hashtable.h:28:9: note: this is the location of the previous definition
28 | #define HASH_BITS(name) ilog2(HASH_SIZE(name))
| ^~~~~~~~~
fs/fuse/dir.c:36:9: warning: ?HASH_SIZE? redefined
36 | #define HASH_SIZE (1 << HASH_BITS)
| ^~~~~~~~~
./include/linux/hashtable.h:27:9: note: this is the location of the previous definition
27 | #define HASH_SIZE(name) (ARRAY_SIZE(name))
| ^~~~~~~~~
Hence rename the HASH_SIZE/HASH_BITS in fuse, by prefixing them with
FUSE_ instead.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Link: https://patch.msgid.link/195c9525-281c-4302-9549-f3d9259416c6@kernel.dk
Acked-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
The recent conversion of fuse_reverse_inval_entry() to use
start_removing() was wrong.
As Val Packett points out the original code did not call ->lookup
while the new code does. This can lead to a deadlock.
Rather than using full_name_hash() and d_lookup() as the old code
did, we can use try_lookup_noperm() which combines these. Then
the result can be given to start_removing_dentry() to get the required
locks for removal. We then double check that the name hasn't
changed.
As 'dir' needs to be used several times now, we load the dput() until
the end, and initialise to NULL so dput() is always safe.
Reported-by: Val Packett <val@packett.cool>
Closes: https://lore.kernel.org/all/6713ea38-b583-4c86-b74a-bea55652851d@packett.cool
Fixes: c9ba789dad ("VFS: introduce start_creating_noperm() and start_removing_noperm()")
Signed-off-by: NeilBrown <neil@brown.name>
Link: https://patch.msgid.link/176454037897.634289.3566631742434963788@noble.neil.brown.name
Signed-off-by: Christian Brauner <brauner@kernel.org>
Pull fuse updates from Miklos Szeredi:
- Add mechanism for cleaning out unused, stale dentries; controlled via
a module option (Luis Henriques)
- Fix various bugs
- Cleanups
* tag 'fuse-update-6.19' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse:
fuse: Uninitialized variable in fuse_epoch_work()
fuse: fix io-uring list corruption for terminated non-committed requests
fuse: signal that a fuse inode should exhibit local fs behaviors
fuse: Always flush the page cache before FOPEN_DIRECT_IO write
fuse: Invalidate the page cache after FOPEN_DIRECT_IO write
fuse: rename 'namelen' to 'namesize'
fuse: use strscpy instead of strcpy
fuse: refactor fuse_conn_put() to remove negative logic.
fuse: new work queue to invalidate dentries from old epochs
fuse: new work queue to periodically invalidate expired dentries
dcache: export shrink_dentry_list() and add new helper d_dispose_if_unused()
fuse: add WARN_ON and comment for RCU revalidate
fuse: Fix whitespace for fuse_uring_args_to_ring() comment
fuse: missing copy_finish in fuse-over-io-uring argument copies
fuse: fix readahead reclaim deadlock
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()
Pull directory delegations update from Christian Brauner:
"This contains the work for recall-only directory delegations for
knfsd.
Add support for simple, recallable-only directory delegations. This
was decided at the fall NFS Bakeathon where the NFS client and server
maintainers discussed how to merge directory delegation support.
The approach starts with recallable-only delegations for several reasons:
1. RFC8881 has gaps that are being addressed in RFC8881bis. In
particular, it requires directory position information for
CB_NOTIFY callbacks, which is difficult to implement properly
under Linux. The spec is being extended to allow that information
to be omitted.
2. Client-side support for CB_NOTIFY still lags. The client side
involves heuristics about when to request a delegation.
3. Early indication shows simple, recallable-only delegations can
help performance. Anna Schumaker mentioned seeing a multi-minute
speedup in xfstests runs with them enabled.
With these changes, userspace can also request a read lease on a
directory that will be recalled on conflicting accesses. This may be
useful for applications like Samba. Users can disable leases
altogether via the fs.leases-enable sysctl if needed.
VFS changes:
- Dedicated Type for Delegations
Introduce struct delegated_inode to track inodes that may have
delegations that need to be broken. This replaces the previous
approach of passing raw inode pointers through the delegation
breaking code paths, providing better type safety and clearer
semantics for the delegation machinery.
- Break parent directory delegations in open(..., O_CREAT) codepath
- Allow mkdir to wait for delegation break on parent
- Allow rmdir to wait for delegation break on parent
- Add try_break_deleg calls for parents to vfs_link(), vfs_rename(),
and vfs_unlink()
- Make vfs_create(), vfs_mknod(), and vfs_symlink() break delegations
on parent directory
- Clean up argument list for vfs_create()
- Expose delegation support to userland
Filelock changes:
- Make lease_alloc() take a flags argument
- Rework the __break_lease API to use flags
- Add struct delegated_inode
- Push the S_ISREG check down to ->setlease handlers
- Lift the ban on directory leases in generic_setlease
NFSD changes:
- Allow filecache to hold S_IFDIR files
- Allow DELEGRETURN on directories
- Wire up GET_DIR_DELEGATION handling
Fixes:
- Fix kernel-doc warnings in __fcntl_getlease
- Add needed headers for new struct delegation definition"
* tag 'vfs-6.19-rc1.directory.delegations' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
vfs: add needed headers for new struct delegation definition
filelock: __fcntl_getlease: fix kernel-doc warnings
vfs: expose delegation support to userland
nfsd: wire up GET_DIR_DELEGATION handling
nfsd: allow DELEGRETURN on directories
nfsd: allow filecache to hold S_IFDIR files
filelock: lift the ban on directory leases in generic_setlease
vfs: make vfs_symlink break delegations on parent dir
vfs: make vfs_mknod break delegations on parent directory
vfs: make vfs_create break delegations on parent directory
vfs: clean up argument list for vfs_create()
vfs: break parent dir delegations in open(..., O_CREAT) codepath
vfs: allow rmdir to wait for delegation break on parent
vfs: allow mkdir to wait for delegation break on parent
vfs: add try_break_deleg calls for parents to vfs_{link,rename,unlink}
filelock: push the S_ISREG check down to ->setlease handlers
filelock: add struct delegated_inode
filelock: rework the __break_lease API to use flags
filelock: make lease_alloc() take a flags argument
The fuse_ilookup() function only sets *fm on the success path so this
"if (fm) {" NULL check doesn't work. The "fm" pointer is either
uninitialized or valid. Check the "inode" pointer instead.
Also, while it's not necessary, it is cleaner to move the iput(inode)
under the NULL check as well.
Fixes: 64becd224f ("fuse: new work queue to invalidate dentries from old epochs")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Reviewed-by: Luis Henriques <luis@igalia.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
xfs, fuse, ipc/mqueue need variants of start_creating or start_removing
which do not check permissions.
This patch adds _noperm versions of these functions.
Note that do_mq_open() was only calling mntget() so it could call
path_put() - it didn't really need an extra reference on the mnt.
Now it doesn't call mntget() and uses end_creating() which does
the dput() half of path_put().
Also mq_unlink() previously passed
d_inode(dentry->d_parent)
as the dir inode to vfs_unlink(). This is after locking
d_inode(mnt->mnt_root)
These two inodes are the same, but normally calls use the textual
parent.
So I've changes the vfs_unlink() call to be given d_inode(mnt->mnt_root).
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: NeilBrown <neil@brown.name>
--
changes since v2:
- dir arg passed to vfs_unlink() in mq_unlink() changed to match
the dir passed to lookup_noperm()
- restore assignment to path->mnt even though the mntget() is removed.
Link: https://patch.msgid.link/20251113002050.676694-7-neilb@ownmail.net
Tested-by: syzbot@syzkaller.appspotmail.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
By "length of a string" usually the number of non-null chars is
meant (i.e. strlen(str)). So the variable 'namelen' was confusingly
named, whereas 'namesize' refers more to what's being done in
'get_security_context'.
Suggested-by: Miklos Szeredi <miklos@szeredi.hu>
Signed-off-by: Miquel Sabaté Solà <mssola@mssola.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
As pointed out in [1], strcpy() is deprecated in favor of strscpy().
Furthermore, the size of the buffer for the name to be copied is well known
at this point since we are going to move the pointer by that much on the
next line. Hence, it's safe to assume 'namelen' for the size of the string
to be copied.
[1] https://github.com/KSPP/linux/issues/88
Signed-off-by: Miquel Sabaté Solà <mssola@mssola.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
With the infrastructure introduced to periodically invalidate expired
dentries, it is now possible to add an extra work queue to invalidate
dentries when an epoch is incremented. This work queue will only be
triggered when the 'inval_wq' parameter is set.
Signed-off-by: Luis Henriques <luis@igalia.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
This patch adds the necessary infrastructure to keep track of all dentries
created for FUSE file systems. A set of rbtrees, protected by hashed
locks, will be used to keep all these dentries sorted by expiry time.
A new module parameter 'inval_wq' is also added. When set, it will start
a work queue which will periodically invalidate expired dentries. The
value of this new parameter is the period, in seconds, for this work
queue. Once this parameter is set, every new dentry will be added to one
of the rbtrees.
When the work queue is executed, it will check all the rbtrees and will
invalidate those dentries that have timed-out.
The work queue period can not be smaller than 5 seconds, but can be
disabled by setting 'inval_wq' to zero (which is the default).
Signed-off-by: Luis Henriques <luis@igalia.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
When nfsd starts requesting directory delegations, setlease handlers may
see requests for leases on directories. Push the !S_ISREG check down
into the non-trivial setlease handlers, so we can selectively enable
them where they're supported.
FUSE is special: It's the only filesystem that supports atomic_open and
allows kernel-internal leases. atomic_open is issued when the VFS
doesn't know the state of the dentry being opened. If the file doesn't
exist, it may be created, in which case the dir lease should be broken.
The existing kernel-internal lease implementation has no provision for
this. Ensure that we don't allow directory leases by default going
forward by explicitly disabling them there.
Reviewed-by: NeilBrown <neil@brown.name>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Link: https://patch.msgid.link/20251111-dir-deleg-ro-v6-4-52f3feebb2f2@kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
Now that fuse is integrated with iomap for read/readahead, we can remove
the workaround that was added in commit bd24d2108e ("fuse: fix fuseblk
i_blkbits for iomap partial writes"), which was previously needed to
avoid a race condition where an iomap partial write may be overwritten
by a read if blocksize < PAGE_SIZE. Now that fuse does iomap
read/readahead, this is protected against since there is granular
uptodate tracking of blocks, which means this workaround can be removed.
Signed-off-by: Joanne Koong <joannelkoong@gmail.com>
Tested-by: syzbot@syzkaller.appspotmail.com
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
